U.S. patent application number 10/861935 was filed with the patent office on 2004-11-25 for protective thin film for fpds, method for producing said thin film and fpds using said thin film.
Invention is credited to Kuromitsu, Yoshirou, Sakurai, Hideaki, Yamashita, Yukiya.
Application Number | 20040234751 10/861935 |
Document ID | / |
Family ID | 27472009 |
Filed Date | 2004-11-25 |
United States Patent
Application |
20040234751 |
Kind Code |
A1 |
Sakurai, Hideaki ; et
al. |
November 25, 2004 |
Protective thin film for FPDs, method for producing said thin film
and FPDs using said thin film
Abstract
The present invention provides a protecting film capable of
preventing deterioration in adhesion and matching to a substrate
(dielectric layer), and deterioration in electric insulation. The
protecting film includes a film body composed of MgO or the like
which is inhibited from reacting with CO.sub.2 gas and H.sub.2O gas
in air to prevent degeneration of MgO or the like into MgCO.sub.3
and Mg(OH).sub.2, etc. harmful to FPD. The film body is formed on
the surface of the substrate, and the fluoride layer is formed on
the surface of the film body. The fluoride layer is represented by
MO.sub.XF.sub.Y (M is Mg, Ca, Sr, Ba, an alkali earth complex
metal, a rare earth metal, or a complex metal of an alkali earth
metal and a rare earth metal, 0.ltoreq.X<2, and
0<Y.ltoreq.4), and is obtained by reaction of a gaseous
fluorinating agent with MgO or the like. As the gaseous
fluorinating agent, a fluorine gas, a hydrogen fluoride gas,
BF.sub.3, SbF.sub.5 or SF.sub.4 is preferably used.
Inventors: |
Sakurai, Hideaki;
(Saitama-ken, JP) ; Yamashita, Yukiya;
(Saitama-ken, JP) ; Kuromitsu, Yoshirou;
(Saitama-ken, JP) |
Correspondence
Address: |
OBLON, SPIVAK, MCCLELLAND, MAIER & NEUSTADT, P.C.
1940 DUKE STREET
ALEXANDRIA
VA
22314
US
|
Family ID: |
27472009 |
Appl. No.: |
10/861935 |
Filed: |
June 7, 2004 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
10861935 |
Jun 7, 2004 |
|
|
|
09457743 |
Dec 10, 1999 |
|
|
|
Current U.S.
Class: |
428/332 ;
428/688 |
Current CPC
Class: |
Y10T 428/265 20150115;
C03C 2218/355 20130101; Y10T 428/26 20150115; C03C 2218/32
20130101; C03C 17/3452 20130101 |
Class at
Publication: |
428/332 ;
428/688 |
International
Class: |
B32B 001/00 |
Foreign Application Data
Date |
Code |
Application Number |
Dec 10, 1998 |
JP |
10-351167 |
May 18, 1999 |
JP |
11-136599 |
May 20, 1999 |
JP |
11-139766 |
Jun 28, 1999 |
JP |
11-182814 |
Claims
1. (Canceled)
2. A FPD protecting film comprising a film body comprising of any
one of MgO, CaO, SrO, BaO, an alkali earth compound oxide, a rare
earth oxide, and a compound oxide of alkali earth oxides and rare
earth oxides, wherein the film body is present on the surface of a
substrate and is formed from a fluoride layer-coated powder of any
one of MgO, CaO, SrO, BaO, alkali earth compound oxides, rare earth
oxides, and compound oxides of alkali earth oxides and rare earth
oxides.
3-6. (Canceled).
7. A method of producing a FPD protecting film comprising: forming
a film body comprising any one of MgO, CaO, SrO, BaO, an alkali
earth compound oxide, a rare earth oxide, and a compound oxide of
alkali earth oxides and rare earth oxides on the surface of a
substrate; and treating the surface of the film body with a gaseous
fluorinating agent to form a fluoride layer on the surface of the
film body.
8. The method of producing a FPD protecting film according to claim
7, comprising: forming the film body on the surface of the
substrate in a vacuum; and treating the surface of the film body
with a gaseous fluorinating agent in a vacuum or an inert gas
atmosphere without exposing the film body to air.
9. The method of producing a FPD protecting film according to claim
7, comprising: forming the film body on the surface of the
substrate in a vacuum; burning the film body in air to activate the
film body after exposing it to air; and treating the surface of the
film body with a gaseous fluorinating agent to form a fluoride
layer on the surface of the film body.
10. The method of producing a FPD protecting film according to
claim 8, further comprising burning the film body in air before,
during and after assembly of a panel using the substrate on the
surface of which the film body and the fluoride layer are
formed.
11. A method of producing a FPD protecting film comprising:
treating the surfaces of a powder of any one of MgO, CaO, SrO, BaO,
an alkali earth compound oxide, a rare earth oxide, and a compound
oxide of alkali earth oxides and rare earth oxides, with a gaseous
fluorinating agent to coat the powder with a fluoride layer to form
a fluoride layer-coated powder; mixing the fluoride layer-coated
powder, a binder, and a solvent to prepare paste or a dispersion
for a film; and forming a film body on the surface of a substrate
with the paste or dispersion for a film.
12. The method of producing a FPD protecting film according to
claim 7, wherein the surface of the film body, or the surface of
the powder is treated with the gaseous fluorinating agent at a
pressure of 1 to 760 Torr.
13. The method of producing a FPD protecting film according to
claim 7, wherein the gaseous fluorinating agent comprises at least
one of a fluorine gas, a hydrogen fluoride gas, BF.sub.3, SbF.sub.5
or SF.sub.4.
14. The powder for producing a FPD protecting film according to
claim 2, which is coated with a fluoride layer.
15. The powder according to claim 14, wherein the thickness of the
fluoride layer is 0.1 to 1000 nm.
16. A paste for a film prepared by mixing a powder of any one of
MgO, CaO, SrO, BaO, an alkali earth compound oxide, a rare earth
oxide, and a compound oxide of alkali earth oxides and rare earth
oxides, which is coated with a fluoride layer, according to claim
14, a binder and a solvent.
17: A dispersion for a film prepared by mixing a powder of any one
of MgO, CaO, SrO, BaO, an alkali earth compound oxide, a rare earth
oxide, and a compound oxide of alkali earth oxides and rare earth
oxides, which is coated with a fluoride layer, according to claim
14, a binder and a solvent.
18. (Canceled).
19. A method of producing a FPD protecting film comprising: forming
a protecting film comprising a powder of any one of MgO, CaO, SrO,
BaO, an alkali earth compound oxide, a rare earth oxide, and a
compound oxide of alkali earth oxides and rare earth oxides on a
substrate; treating the surface of the protecting film with a
gaseous fluorinating agent to form a fluoride layer on the surface
of the protecting film; and removing the fluoride layer after a FPD
is assembled with the substrate.
20. The method of producing a FPD protecting film according to
claim 19, wherein the fluoride layer is represented by
MO.sub.XF.sub.Y wherein M is Mg, Ca, Sr, Ba, an alkali earth
complex metal, a rare earth metal, or a complex metal of an alkali
earth metal and rare earth metal, 0.ltoreq.X<2, and
0<Y.ltoreq.4.
21. The method of producing a FPD protecting film according to
claim 19, wherein the fluoride layer is obtained by reaction of a
gaseous fluorinating agent with an alkali earth metal oxide, an
alkali earth metal compound oxide, a rare earth metal oxide, or a
compound oxide of an alkali earth metal and a rare earth metal.
22. The method of producing a FPD protecting film according to
claim 21, wherein the gaseous fluorinating agent comprises any one
of a fluorine gas a hydrogen fluoride gas, BF.sub.3, SbF.sub.5 and
SF.sub.4.
23. The method of producing a FPD protecting film according to
claim 19, wherein the thickness of the fluoride layer is 0.1 to
1000 nm.
24. A FPD protecting film produced by a method according to claim
19.
25. A FPD comprising a protecting film according to claim 24.
26. The method of producing a FPD protecting film according to
claim 11, wherein the surface of the film body, or the surface of
the powder is treated with the gaseous fluorinating agent at a
pressure of 1 to 760 Torr.
27. The method of producing a FPD protecting film according to
claim 11, wherein the gaseous fluorinating agent comprises a
fluorine gas, a hydrogen fluoride gas, BF.sub.3, SbF.sub.5 or
SF.sub.4.
Description
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The present invention relates to a protecting film for FPD
(Flat Panel Display) such as PDP (Plasma Display Panel), PALC
(Plasma Addressed Liquid Crystal Display), and the like, a method
of producing the same, and FPD using the same.
[0003] 2. Description of the Related Art
[0004] As a method of forming a protecting film at low cost with
excellent productivity as compared with a method of forming a FPD
protecting film using a vacuum process such as an electron beam
deposition process, a sputtering process, an ion plating process,
or the like, various methods have been proposed. These proposed
methods use a wet process such as a screen printing process, a spin
coating process, a spray coating process, or the like using paste
or a coating solution containing a MgO powder, a Mg(OH).sub.2
powder, a mixture of MgO powder and Mg(OH).sub.2 powder, or a rare
earth oxide powder (for example, Japanese Unexamined Patent
Publication Nos. 3-67437, 7-220640, 7-147136, 7-335134, 8-111177,
8-111178, 8-212917, 6-325696, 8-167381, 8-264125, 9-12940, 9-12976,
8-96718, etc.).
[0005] As this type of protecting film, a secondary electron
emitting material for a plasma display panel is disclosed, which
comprises a pair of discharge maintaining electrodes, a dielectric
layer and a protecting layer, which are laminated on a back glass
substrate, a fluorescent layer formed on the rear side of a front
glass substrate, and an inert gas sealed between both substrates
and emitting ultraviolet rays by discharge, the protecting layer
being composed of a secondary electron emitting material such as
fluorinated MgO (Japanese Unexamined Patent Publication No.
7-201280). In this secondary electron emitting material, oxygen of
MgO which constitutes the protecting layer is partially replaced by
fluorine. Namely, the oxygen atoms of a lattice which forms a MgO
ion crystal are partially replaced by fluorine atoms to form
fluorinated MgO represented by the formula MgO.sub.1-X-YF.sub.Y
(wherein 0<X<1 and 0<Y<1).
[0006] This secondary electron emitting material for a plasma
display panel uses fluorinated MgO represented by
MgO.sub.1-X-YF.sub.Y as the protecting layer, and thus forms
localized levels by valence control, thereby decreasing the
break-down voltage. As a result, it is possible to form a
high-definition panel, and obtain a protecting film stable with the
passage of time.
[0007] On the other hand, as a PDP protecting film which is
directly exposed to a discharge space and is thus a key material
playing the most important role in discharge characteristics, a MgO
film having the high secondary electron emitting ability, and
excellent sputtering performance, light transmission, and
insulating property is conventionally used.
[0008] However, the MgO film is easily degenerated due to reaction
with CO.sub.2 and H.sub.2O when exposed to air during the process.
Therefore, it is known that in order to obtain the original
characteristics of MgO, degassing evacuation must be carried out
under vacuum and heating for a long time after panel sealing (for
example, Latest Plasma Display Manufacturing Technology, edited by
Sato, Press Journal, p. 118-123 and p. 291-295 (1997)). This is
because impurity gases of H.sub.2O, H.sub.2, O.sub.2, CO, CO.sub.2,
N.sub.2, and the like adversely affect discharge characteristics of
PDP and a constituent material of a panel, and particularly,
contamination with CO.sub.2 deteriorates panel characteristics to
an unrecoverable level.
[0009] Therefore, in order to prevent degeneration of MgO, it has
been proposed to coat the surface of MgO with another material
having low moisture permeability (Japanese Unexamined Patent
Publication No. 10-149767, and W, T, Lee et al; "LaF.sub.3 coated
MgO protecting layer in AC-Plasma Display Panels", IDW'99, P.
72-75).
[0010] The above Japanese Unexamined Patent Publication No.
10-149767 discloses a method of manufacturing PDP comprising
forming a protecting film, forming a temporary protecting film with
low moisture permeability on the protecting film, and then removing
the temporary protecting film. In this method, the surface of the
protecting film is protected by the temporary protecting film
during manufacture of PDP, preventing the formation of a
degenerated layer on the surface of the protecting film. As a
result, a protecting film having good discharge characteristics can
be obtained, and pyrolysis of the degenerated layer of the
protecting film is made unnecessary.
[0011] The above document of W. T. Lee et al proposes that
LaF.sub.3 coating having low moisture permeability on a MgO
protecting film can suppress degeneration of the MgO protecting
film, and realize a higher degree of secondary-electron emitting
property and a lower degree of discharge property.
[0012] However, in the conventional method of forming a protecting
film disclosed in each of the above publications, a MgO powder, a
Mg(OH).sub.2 powder, a MgO powder obtained by burning a mixture of
MgO powder and Mg(OH).sub.2 powder, or a rare earth oxide powder
comprises fine particles and thus has a large surface area, thereby
causing the probability that the surfaces relatively readily react
with carbon dioxide and moisture in air to form a carbonate and
hydroxide. There is thus a problem in that carbon dioxide and
moisture are released to the discharge space during discharge of
PDP to deteriorate discharge characteristics.
[0013] In addition, the secondary-electron emitting material for a
plasma display panel disclosed in Japanese Unexamined Patent
Publication No. 7-201280 comprises a protecting layer composed of
fluorinated MgO represented by MgO.sub.1-X-YF.sub.Y, and thus has a
problem in that since a difference between the thermal expansion
coefficients of the protecting layer and a substrate (dielectric
layer) is relatively large, the protecting layer and the substrate
(dielectric layer) have low adhesion and matching therebetween, and
poor electric insulation as compared with the use of a MgO film as
a protecting layer.
[0014] Furthermore, the PDP manufacturing method disclosed in
Japanese Unexamined Patent Publication No. 10-149767 and the
document of W. T. Lee et al is difficult to match the temporary
protecting film and the protecting film in formation of the
temporary protecting film, and thus causes cracks in the temporary
protecting film or peeling of the temporary protecting film,
thereby causing the insufficient effect of preventing degeneration
of the protecting film by the temporary protecting film. A possible
method of improving this is to coat a thick temporary protecting
film on a protecting film. However, this method has the problem of
producing large amounts of impurities (decomposition products of
the temporary protecting film) in removal of the temporary
protecting film.
[0015] Furthermore, the document of W. T. Lee et al discloses that
LaF.sub.3 is coated to 5 to 90 nm on MgO. However, such a two-layer
structure has a problem in that the break-down voltage is rapidly
changed when the LaF.sub.3 upper layer film is removed by
sputtering, thereby failing to obtain a sufficient life time.
SUMMARY OF THE INVENTION
[0016] Accordingly, a first object of the present invention is to
provide a FPD protecting film and a method of producing the same
which is capable of preventing deterioration in adhesion and
matching with a substrate (dielectric layer), and preventing
deterioration in electric insulation.
[0017] A second object of the present invention is to provide a FPD
protecting film and a method of producing the same which is capable
of inhibiting or suppressing reaction of MgO or the like in a film
body, a film or the protecting film with CO.sub.2 gas and H.sub.2O
gas in air to prevent or suppress degeneration of MgO to
MgCO.sub.3, Mg(OH).sub.2, etc. harmful to FPD, i.e., capable of
improving the environment resistance of the film body, the film or
the protecting film.
[0018] A third object of the present invention is to provide a FPD
protecting film and a method of producing the same which is capable
of preventing or suppressing the formation of a carbonate
(MgCO.sub.3 or the like), a hydroxide (Mg(OH).sub.2) etc. of MgO
before the formation of a fluoride layer on the surface of a film
body to shorten the time of the vacuum evacuation heating step or
omit the vacuum evacuation heating step during manufacture of
FPD.
[0019] A fourth object of the present invention is to provide a FPD
protecting film and a method of producing the same which permits
the relatively easy formation of a fluoride layer with a high
secondary-electron emitting ability on the surface of a film body
or the surfaces of MgO powder which constitutes the film.
[0020] A fifth object of the present invention is to provide FPD
using a protecting film which is capable of significantly
decreasing the number of production steps.
[0021] A sixth object of the present invention is to provide a
method of producing a FPD protecting film, which is capable of
improving matching between a fluoride layer and a protecting film
to prevent the occurrence of cracks in the fluoride layer and
peeling of the fluoride layer in the FPD manufacturing process, and
improve the effect of preventing degeneration of the protecting
film by the fluoride layer.
[0022] A seventh object of the present invention is to provide a
FPD protecting film and a method of producing the same which
permits the removal of a fluoride layer after assembly of FPD to
improve the discharge characteristics.
[0023] In accordance with claim 1 of the present invention, as
shown in FIGS. 1 and 2, a FPD protecting film comprises a film body
14a formed on a substrate 13 and made of any one of MgO, CaO, SrO,
BaO, alkali earth compound oxides, rare earth oxides, and compound
oxides of alkali earth oxides and rare earth oxides; and a fluoride
layer 14b formed on the surface of the film body 14a.
[0024] In the FPD protecting film in accordance with claim 1, the
surface of the film body 14a is coated with the fluoride layer 14b,
and thus MgO or the like in the film body 14a little reacts with
CO.sub.2 gas and H.sub.2O gas in air even when the protecting 14 is
exposed to air for a long time in the process for manufacturing FPD
10 (refer to FIG. 2). As a result, MgO or the like in the film body
14a is little degenerated to MgCO.sub.3 and Mg(OH).sub.2 which
possibly deteriorate the function of the FPD 10.
[0025] Since the film body 14a having substantially the same
thermal expansion coefficient as the substrate 13 is bonded to the
substrate 13, the protecting 14 is not separated from the substrate
13 due to a heat cycle, thereby causing high adhesion and matching
between the protecting 14 and the substrate 13.
[0026] In accordance with claim 2 of the present invention, as
shown in FIGS. 3 and 4, a FPD protecting film comprises a film body
34a formed on a substrate 13 and made of any one of MgO, CaO, SrO,
BaO, alkali earth compound oxides, rare earth oxides, and compound
oxides of alkali earth oxides and rare earth oxides, wherein the
film body 34a is formed by using a fluoride layer-coated powder of
any one of MgO, CaO, SrO, BaO, alkali earth compound oxides, rare
earth oxides, and compound oxides of alkali earth oxides and rare
earth oxides.
[0027] In the FPD protecting film in accordance with claim 2, the
surfaces of MgO powder particles or the like are coated with
fluoride layers, and thus MgO or the like in the film body 34a
little reacts with CO.sub.2 gas and H.sub.2O gas in air even when
the protecting film 34 is exposed to air in the manufacturing
process (refer to FIG. 4). As a result, MgO or the like in the film
body 34a is little degenerated to MgCO.sub.3, Mg(OH).sub.2, etc.
having the probability of deteriorating the function of FPD 10.
Since the fluoride layers coated on the surfaces of MgO powder or
the like are very thin, the mechanical characteristics of the MgO
powder or the like are substantially the same as a MgO powder or
the like with no fluoride layer coated on the surfaces thereof.
[0028] The fluoride layer 14b is preferably represented by
MO.sub.XF.sub.Y (M is Mg, Ca, Sr, Ba, an alkali earth complex
metal, a rare earth metal, or a complex metal of an alkali earth
metal and a rare earth metal, 0.ltoreq.X<2, and
0<Y.ltoreq.4).
[0029] The fluoride layer 14b is preferably obtained by reaction of
a gaseous fluorinating agent with any one of MgO, CaO, SrO, BaO,
alkali earth compound oxides, rare earth oxides, and compound
oxides of alkali earth oxides and rare earth oxides.
[0030] Furthermore, as the gaseous fluorinating agent, any one of
fluorine gas, hydrogen fluoride gas, BF.sub.3, SbF.sub.5 and
SF.sub.4, particularly, fluorine gas or hydrogen fluoride gas, is
preferably used. The thickness of the fluoride layer is preferably
set in the range of 0.1 to 1000 nm.
[0031] In accordance with claim 7 of the present invention, a
method of producing a FPD protecting film comprises forming a film
body 14a on a substrate 13 by using any one of MgO, CaO, SrO, BaO,
alkali earth compound oxides, rare earth oxides, and compound
oxides of alkali earth oxides and rare earth oxides; and treating
the surface of the film body with a gaseous fluorinating agent to
form a fluoride layer 14b on the surface of the film body 14a, as
shown in FIGS. 1 and 2.
[0032] In the method of producing a FPD protecting film in
accordance with claim 7, MgO or the like in the film body 14a is
little degenerated to MgCO.sub.3 and Mg(OH).sub.2 which are harmful
to the function of the FDP 10 (refer to FIG. 2), thereby shortening
the time of the subsequent degassing step for removing MgCO.sub.3
and Mg(OH).sub.2 or omitting the subsequent degassing step.
[0033] In accordance with claim 8 of the present invention, the
method according to claim 7 comprises forming a film body 14a on a
substrate 13 in a vacuum, and treating the surface of the film body
14a with a gaseous fluorinating agent in a vacuum or an inert gas
atmosphere without exposing the film body 14a to air to form a
fluoride layer 14b on the surface of the film body 14a, as shown in
FIGS. 1 and 2.
[0034] In the method of producing a FPD protecting film in
accordance with claim 8, after the film body 14a is formed on the
surface of the substrate 13, the film body 14a is not exposed to
air before the fluoride layer 14b is formed on the surface of the
film body 14a, thereby preventing or suppressing the production of
carbonate (MgCO.sub.3, or the like.) and hydroxide (Mg(OH).sub.2,
or the like) of MgO, which are harmful to the FPD, on the surface
of the film body 14a.
[0035] In accordance with claim 9 of the present invention, the
method according to claim 7 comprises forming a film body 14a on a
substrate 13 in a vacuum, burning the film body 14a in air after
exposing the film body 14a to air to activate the film body 14a,
and treating the surface of the film body 14a with a gaseous
fluorinating agent to form a fluoride layer 14b on the surface of
the film body 14a, as shown in FIGS. 1 and 2.
[0036] In the method of producing a FPD protecting film in
accordance with claim 9, after the film body 14a is formed on the
surface of the substrate 13, the film body 14a is exposed to air
and burned in air to be activated. Therefore, even when carbonate
(MgCO.sub.3, or the like) and hydroxide (Mg(OH).sub.2, or the like)
of MgO, which are harmful to the FPD, are formed on the surface of
the film body 14a, the carbonate (MgCO.sub.3, or the like) and
hydroxide (Mg(OH).sub.2, or the like) of MgO are removed as
CO.sub.2 and H.sub.2O by burning in air. In this sate, the fluoride
layer 14b is formed on the surface of the film body 14a to protect
the surface of the film body 14a by the fluoride layer 14b, thereby
preventing and suppressing the formation of carbonate (MgCO.sub.3,
or the like) and hydroxide (Mg(OH).sub.2, or the like) of MgO.
[0037] In accordance with claim 10 of the present invention, the
method according to claim 8 or 9 further comprises activating the
film body 14a before, during or after the substrate 13 on which the
film body 14a and the fluoride layer 14b are formed is assembled
into a panel.
[0038] In the method of producing a FPD protecting film according
to claim 10, since the film body 14a is activated by burning after
the fluoride layer 14b is formed on the surface of the film body
14a, even when hydroxide (Mg(OH).sub.2, or the like) of MgO or the
like is formed a little on the film body 14a, the hydroxide can be
removed as H.sub.2O, thereby decreasing the rate of recontamination
of the film body 14a with atmospheric moisture.
[0039] In accordance with claim 11 of the present invention, a
method of producing a FPD protecting film comprises treating, with
a gaseous fluorinating agent, the surfaces of a powder of any one
of MgO, CaO, SrO, BaO, alkali earth compound oxides, rare earth
oxides, and compound oxides of alkali earth oxides and rare earth
oxides to coat fluoride layers on the powder surfaces of any one of
MgO, CaO, SrO, BaO, alkali earth compound oxides, rare earth
oxides, and compound oxides of alkali earth oxides and rare earth
oxides; mixing a binder, a solvent and the fluoride layer-coated
powder of any one of MgO, CaO, SrO, BaO, alkali earth compound
oxides, rare earth oxides, and compound oxides of alkali earth
oxides and rare earth oxides to prepare paste or a dispersion for a
film; and forming a film body 34a on the surface of a substrate 13
by using the paste or dispersion for a film, as shown in FIGS. 3
and 4.
[0040] In the method of producing a FPD protecting film according
to claim 11, since MgO or the like in the film body 34a is little
degenerated to MgCO.sub.3, Mg(OH).sub.2, etc. harmful to the
function of the FDP 10 (refer to FIG. 4), it is possible to shorten
the time of the subsequent degassing step for removing the
MgCO.sub.3, Mg(OH).sub.2, etc., or omitting the subsequent
degassing step, thereby decreasing the manufacturing cost of the
FPD 10.
[0041] In the method according to any one of claims 7 to 11 of the
present invention, the film body 14a made of any one of MgO, CaO,
SrO, BaO, alkali earth compound oxides, rare earth oxides, and
compound oxides of alkali earth oxides and rare earth oxides, or
the power of any one of MgO, CaO, SrO, BaO, alkali earth compound
oxides, rare earth oxides, and compound oxides of alkali earth
oxides and rare earth oxides is preferably surface-treated with the
gaseous fluorinating agent under pressure of 1 to 760 Torr.
[0042] In the method according to any one of claims 7 to 11, as the
gaseous fluorinating agent, any one of fluorine gas, hydrogen
fluoride gas, BF.sub.3, SbF.sub.5 and SF.sub.4, particularly
fluorine gas or hydrogen fluoride gas, is preferably used.
[0043] In accordance with claim 14, a powder of any one of MgO,
CaO, SrO, BaO, alkali earth compound oxides, rare earth oxides, and
compound oxides of alkali earth oxides and rare earth oxides is
coated with a fluoride layer in order to form a FPD protecting film
34 according to claim 2.
[0044] In accordance with claim 15, the thickness of the fluoride
layer coated on the powder according to claim 14 is preferably 0.1
to 1000 nm.
[0045] In accordance with claim 16, the paste for a film is
prepared by mixing a binder, a solvent, and the fluoride
layer-coated powder of any one of MgO, CaO, SrO, BaO, alkali earth
compound oxides, rare earth oxides, and compound oxides of alkali
earth oxides and rare earth oxides according to claim 14 or 15.
[0046] In accordance with claim 17, the dispersion for a film is
prepared by mixing a binder, a solvent, and the fluoride
layer-coated powder of any one of MgO, CaO, SrO, BaO, alkali earth
compound oxides, rare earth oxides, and compound oxides of alkali
earth oxides and rare earth oxides according to claim 14 or 15.
[0047] The use of the paste or dispersion for a film containing the
fluoride layer-coated powder permits easy formation of a film body
according to claim 2.
[0048] In accordance with claim 18 of the present invention, FPD
uses a protecting film according to any one of claims 1 to 6.
[0049] The FPD according to claim 18 of the present invention
permits a significant decrease in number of steps for manufacturing
FPD, and manufacture at low cost.
[0050] In accordance with claim 19 of the present invention, a
method of producing a FPD protecting film comprises forming, on the
surface of a substrate 13, a protecting film 54 made of any one of
alkali earth metal oxides, alkali earth metal compound oxides, rare
earth metal oxides, and compound oxides of alkali earth metals and
rare earth metals; treating the surface of the protecting film 54
with a gaseous fluorinating agent to form a fluoride layer 55 on
the surface of the protecting film 54; and then removing the
fluoride layer 55 after FDP 10 is assembled by using the substrate
13, as shown in FIG. 5.
[0051] In the method of producing a FPD protecting film according
to claim 19, the protecting film 54 is reacted directly with the
gaseous fluorinating agent to form the fluoride layer 55 on the
surface of the protecting film 54, thereby coating the surface of
the protecting film 54 with the fluoride layer 55. Therefore, even
when the protecting film 54 is exposed to air for a long time
during the process for manufacturing the FPD 10, the protecting
film 54 little reacts with CO.sub.2 gas and water vapor in air. As
a result, the protecting film 54 is little degenerated to a
carbonate, a hydroxide, etc., of an alkali earth metal oxide or the
like, which have the probability of deteriorating the function of
the FPD 10. On the other hand, it is possible to prevent the
occurrence of cracking in the fluoride layer 55 and separation
thereof because of good matching between the fluoride layer 55 and
the protecting film 54, thereby improving the degeneration
protecting effect of the protecting film 54.
[0052] The fluoride layer is preferably represented by
MO.sub.XF.sub.Y (wherein M is Mg, Ca, Sr, Ba, an alkali earth
complex metal, a rare earth metal, or a complex metal of an alkali
earth metal and a rare earth metal, 0.ltoreq.X<2, and
0<Y.ltoreq.4). The fluoride layer is preferably obtained by
reaction of the gaseous fluorinating agent with any one of alkali
earth metal oxides, alkali earth metal compound oxides, rare earth
metal oxides, and compound oxides of alkali earth metals and rare
earth metals.
[0053] Furthermore, as the gaseous fluorinating agent, any one of
fluorine gas, hydrogen fluoride gas, BF.sub.3, SbF.sub.5 and
SF.sub.4, particularly fluorine gas or hydrogen fluoride gas, is
preferably used. The thickness of the fluoride layer is preferably
set in the range of 0.1 to 1000 nm.
[0054] In accordance with claim 24 of the present invention, the
FPD protecting film 54 is produced by this production method
according to any one of claims 19 to 23, as shown in FIG. 5.
[0055] In accordance with claim 25 of the present invention, FDP 10
uses the protecting film 54 according to claim 24, as shown in FIG.
5(d).
[0056] In the FPD protecting film 54 according to claim 24 or 25,
the fluoride layer 55 is removed after assembly of the FPD 10,
thereby improving discharge characteristics of the FPD 10.
BRIEF DESCRIPTION OF THE DRAWINGS
[0057] FIG. 1 is a sectional view showing a front substrate on
which a protecting film in accordance with a first embodiment of
the present invention is formed;
[0058] FIG. 2 is a sectional view showing a principal portion of
PDP in which the front substrate shown in FIG. 1 is
incorporated;
[0059] FIG. 3 is a sectional view showing a front substrate on
which a protecting film in accordance with a second embodiment of
the present invention is formed;
[0060] FIG. 4 is a sectional view showing a principal portion of
PDP in which the front substrate shown in FIG. 3 is
incorporated;
[0061] FIG. 5 is a drawing showing the steps of a process for
manufacturing PDP using a protecting film in accordance with a
third embodiment of the present invention;
[0062] FIG. 6 is a graph showing changes in the amount of
contamination of a film body against the time with changes in the
heat treatment temperature in Examples 301 to 303 and Comparative
Example 301;
[0063] FIG. 7 is a graph showing changes in the amount of
contamination of a film body with changes in the heat treatment
time in Examples 302, 304 and 305; and
[0064] FIG. 8 is a graph showing changes in the amount of
contamination of a film body against the time with fluorination in
Examples 306 and 307.
DESCRIPTION OF THE PREFERRED EMBODIMENT
[0065] A first embodiment of the present invention will be
described with reference to the drawings.
[0066] Examples of FPD of the present invention include PDP, PALC,
and the like. This embodiment relates to PDP.
[0067] As shown in FIGS. 1 and 2, AC-type PDP 10 comprises a back
glass substrate 11, and a front glass substrate 13 which are
combined with partition walls 12 formed at predetermined intervals
therebetween. A film body 14a is formed on the side of the front
glass substrate 13 having display electrodes 16 and a transparent
dielectric layer 17, a fluoride layer 14b being formed on the
surface of the film body 14a, which faces the back glass substrate
11. In the PDP 10, many discharge cells 18 are compartmented by the
back glass substrate 11, the front substrate 13, and the partition
walls 12, and an address electrode 19 is formed on the back glass
substrate 11 in each of the discharge cells 18 so as to be opposed
to the display electrodes 16. In each of the discharge cells 18, a
fluorescent layer 21 is formed in a region ranging from the sides
of the partition walls 12 to the upper surface of the back glass
substrate 11. Furthermore, a discharge gas (not shown) is injected
into each of the discharge cells 18.
[0068] The above fluoride layer 14b is represented by
MO.sub.XF.sub.Y (wherein M is Mg, Ca, Sr, Ba, an alkali earth
complex metal, a rare earth metal, or a complex metal of an alkali
earth metal and a rare earth metal, 0.ltoreq.X<2, and
0<Y.ltoreq.4). For example, the fluoride layer 14b comprises a
MF.sub.2 layer, a MO.sub.0.5F layer, a MO.sub.0.25F.sub.1.5 layer,
a MF.sub.4 layer, a MOF.sub.2 layer, a MF.sub.3 layer, a MOF layer,
a MF.sub.2.66 layer or a MOF.sub.0.66 layer, or the like. The
fluoride layer 14b can be obtained by reaction of a gaseous
fluorinating agent and any one of MgO, CaO, SrO, BaO, alkali earth
compound oxides, rare earth oxides, and compound oxides of alkali
earth oxides and rare earth oxides, which forms the film body 14a.
As the gaseous fluorinating agent, any one of fluorine gas,
hydrogen fluoride gas, BF.sub.3, SbF.sub.5 and SF.sub.4,
particularly, fluorine gas or hydrogen fluoride gas, is preferably
used. The thickness of the fluoride layer 14b is determined by a
balance between improvement in inhibition of reaction of MgO or the
like and CO.sub.2 gas and H.sub.2O gas, and the time of reaction of
MgO or the like and the gaseous fluorinating agent. The thickness
of the fluoride layer 14b is preferably in the range of 0.1 to 1000
nm, more preferably 0.1 to 100 nm. The reason for limiting the
thickness of the fluoride layer 14b in the range of 0.1 to 1000 nm
is that with a thickness of over 1000 nm, the time of reaction of
MgO or the like and the gaseous fluorinating agent is increased to
deteriorate workability.
[0069] The method of producing the PDP protecting film constructed
as described above will be described.
[0070] [1] Formation of Film Body by Evaporation
[0071] First, as shown in FIG. 1, electrode paste for the display
electrodes 16 composed of Ag or Au is coated on the surface of the
front glass substrate 13 at predetermined intervals by screen
printing, dried, and then burned. Then, transparent glass paste for
the transparent dielectric layer 17 is coated over the entire
surface of the front glass substrate 13 by screen printing,
followed by drying. The front glass substrate 13 is dried by
maintaining in air at 100 to 200.degree. C. for 10 to 60 minutes,
and then burned by maintaining in air at 500 to 600.degree. C. for
10 to 60 minutes.
[0072] Next, sintered pellets of any one of MgO, CaO, SrO, BaO,
alkali earth compound oxides, rare earth oxides, and compound
oxides of alkali earth oxides and rare earth oxides, which have a
purity of 99.5% or more, are deposited by evaporation such as
electron beam evaporation or the like to cover the surface of the
transparent dielectric layer 17 of the glass substrate 13, to form
the film body 14a. Deposition conditions of the film body 14a
preferably include an acceleration voltage of 5 to 30 kV, a
deposition pressure of 0.1.times.10.sup.-2 to 10.times.10.sup.-2
Pa, and a deposition distance of 100 to 1000 nm. The front glass
substrate 13 is further maintained in an atmosphere of a gaseous
fluorinating agent (temperature 10 to 100.degree. C.) for 0.1 to
120 minutes to modify the surface of the film body 14a, to form the
fluoride layer 14b on the surface of the film body 14a. As the
gaseous fluorinating agent, any one of fluorine gas, hydrogen
fluoride gas, BF.sub.3, SbF.sub.5 and SF.sub.4, particularly,
fluorine gas or hydrogen fluoride gas, is preferably used. The
pressure of the gaseous fluorinating agent is preferably set in the
range of 1 to 760 Torr, more preferably in the range of 10 to 300
Torr. The reason for limiting the pressure of the gaseous
fluorinating agent in the range of 1 to 760 Torr is that control of
the extent of reaction, i.e., control of the thickness of the
fluoride layer, is facilitated.
[0073] [2] Formation of Film Body by Sputtering
[0074] First, a glass substrate with electrodes is produced by the
same method as described above in [1], and then a film body is
formed on the glass substrate by sputtering using a target composed
of any one of MgO, CaO, SrO, BaO, alkali earth compound oxides,
rare earth oxides, and compound oxides of alkali earth oxides and
rare earth oxides, which have a purity of 99.5% or more, to cover
the surface of the transparent dielectric layer. The deposition
conditions of the film body preferably include a redio-frequency
output of 1 kW, a sputtering pressure of 0.50 to 3.0 Pa, an oxygen
concentration of 5 to 50% based on argon gas, and a substrate
temperature of 20 to 300.degree. C.
[0075] Then, the film body is maintained in an atmosphere of a
gaseous fluorinating agent to modify the surface thereof by the
same method as described above in [1], to form a fluoride layer on
the surface of the film body.
[0076] [3] Formation of Film Body by Screen Printing
[0077] A powder of any one of MgO, CaO, SrO, BaO, alkali earth
compound oxides, rare earth oxide, and compound oxides of alkali
earth oxides and rare earth oxides, which has an average particle
size of 50 to 2000 .ANG., is previously prepared. First, electrode
paste for display electrodes composed of Ag or Au is coated on the
surface of a front glass substrate at predetermined intervals by
screen printing, dried, and then burned. Then, transparent glass
paste for a transparent dielectric layer is coated over the entire
surface of the front glass substrate by screen printing, followed
by drying. Then, the powder of any one of MgO, CaO, SrO, BaO,
alkali earth compound oxides, rare earth oxides, and compound
oxides of alkali earth oxides and rare earth oxides, which
constitutes a film body, a binder, and a solvent are mixed at
predetermined ratios to prepare paste for a film. The thus-prepared
paste is coated over the entire surface of the transparent
dielectric layer by screen printing, and dried.
[0078] As the binder, alkoxide of an alkali earth metal or rare
earth metal, an organic acid compound, acetylacetonate (for
example, organic acid magnesium, magnesium alkoxide, or magnesium
acetylacetonate), ethyl cellulose, or ethyl silicate can be used.
As the solvent, .alpha.-terpineol, butyl carbitol, butyl carbitol
acetate, turpentine oil, or the like can be used. The mixing ratios
of the powder of any one of MgO, CaO, SrO, BaO, alkali earth
compound oxides, rare earth oxides, and compound oxides of alkali
earth oxides and rare earth oxides, the binder, and the solvent are
preferably set to 0 to 10% by weight, 10 to 100% by weight, and 0
to 30% by weight, respectively.
[0079] The front glass substrate is dried by maintaining in air at
100 to 200.degree. C. for 10 to 60 minutes, and then burned by
maintaining in air at 500 to 600.degree. C. for 10 to 60 minutes.
The front glass substrate is further maintained in an atmosphere of
a gaseous fluorinating agent in the same manner as described above
in [1] to modify the surface of the film body, to form a fluoride
layer on the surface of the film body.
[0080] [4] Formation of Film Body by Spin Coating
[0081] Electrode paste and dielectric layer paste are coated o the
surface of a front glass, dried and then burned by the same method
as described above in [3]. Then, a powder of any one of MgO, CaO,
SrO, BaO, alkali earth compound oxides, rare earth oxides, and
compound oxides of alkali earth oxides and rare earth oxides, which
constitutes the film body, a binder, and a solvent are mixed at
predetermined ratios to prepare a dispersion for a film. The
thus-prepared dispersion is deposited over the entire surface of
the transparent dielectric layer by spin coating, and dried. As the
binder, alkoxide of an alkali earth metal or rare earth metal, an
organic acid compound, acetylacetonate (for example, magnesium
alkoxide, organic acid magnesium, or magnesium acetylacetonate),
ethyl silicate, or the like can be used. As the solvent, an
alcohol, cellosolve, or the like can be used. The mixing ratios of
the powder of any one of MgO, CaO, SrO, BaO, alkali earth compound
oxides, rare earth oxides, and compound oxides of alkali earth
oxides and rare earth oxides, the binder, and the solvent are
preferably set to 0 to 40% by weight, 0.1 to 10% by weight, and 55
to 99.9% by weight, respectively. The front glass substrate is
dried by maintaining in air at 40 to 100.degree. C. for 5 to 60
minutes, and then burned by maintaining in air at 500 to
600.degree. C. for 10 to 60 minutes. The front glass substrate is
further maintained in an atmosphere of a gaseous fluorinating agent
in the same manner as described above in [1] to modify the surface
of the film body, to form a fluoride layer on the surface of the
film body.
[0082] Since the PDP protecting film produced by the
above-described method comprises the film body 14a having the
surface coated with the fluoride layer 14b, MgO or the like in the
film body 14a little reacts with CO.sub.2 gas and H.sub.2O gas in
air even when the protecting 14 is exposed to air for a long time
during the process for manufacturing the PDP 10. As a result, MgO
or the like in the film body 14a is little degenerated to
MgCO.sub.3, Mg(OH).sub.2, etc. which have the probability of
deteriorating the function of the PDP 10, thereby improving the
environment resistance of the film body 14a.
[0083] Furthermore, MgO or the like in the film body 14a is little
degenerated to MgCO.sub.3 and Mg(OH).sub.2, thereby shortening the
time of the subsequent degassing step for removing MgCO.sub.3 and
Mg(OH).sub.2 or omitting the subsequent degassing step to decrease
the manufacturing cost of the PDP 10.
[0084] Since the film body 14a having substantially the same
thermal expansion coefficient as the dielectric layer 17 of the
protecting 14 is bonded to the transparent dielectric layer 17, the
protecting 14 is not separated from the transparent dielectric
layer 17 due to a thermal cycle, thereby significantly improving
adhesion and matching to the dielectric layer 17 of the protecting
film 14.
[0085] In the process for forming the protecting 14 described above
in [1] and [2], the following processing [a] or [b] is preferably
carried out.
[0086] [a] The film body 14a is formed on the surface of the glass
substrate 13 in a vacuum, and the surface of the film body 14a is
treated with the gaseous fluorinating agent in a vacuum or an inert
gas atmosphere without exposure to air to form the fluoride layer
14b on the surface of the film body 14a. The inert gas atmosphere
is preferably an atmosphere of argon gas or N.sub.2 gas, and
preferably has a purity of 4N (99.99%), and a dew point of
-65.degree. C. or less, and CO.sub.2 and CO concentrations of 5.0
ppm by volume or less.
[0087] Such treatment can prevent or suppress the formation of
carbonate (MgCO.sub.3 or the like) and hydroxide (Mg(OH).sub.2 or
the like) of MgO or the like, which are harmful to FPD, on the
surface of the film body 14a because the film body 14a is not
exposed to air before the fluoride layer 14b is formed on the
surface of the film body 14a formed on the surface of the substrate
13.
[0088] [b] The film body 14a is formed on the surface of the
substrate 13 in a vacuum, and burned in air to be activated after
it is exposed to air, and the surface thereof is further treated
with the gaseous fluorinating agent to form the fluoride layer 14b
on the surface of the film body 14a. The burning temperature of the
film body 14a in air is 250 to 550.degree. C., preferably 350 to
450.degree. C., and the burning time is 0.1 to 24 hours, preferably
0.2 to 1 hour. The film body 14a is activated by burning at a
temperature for a time in the above ranges. The air has an
atmospheric pressure P.sub.t of 0.1 atm.ltoreq.P.sub.t.ltoreq.- 5.0
atm (preferably 1.0 atm), and the following N.sub.2, O.sub.2,
H.sub.2O and CO.sub.z contents V.sub.N2, V.sub.O2, V.sub.H2O, and
V.sub.COz,
[0089] 65% by volume.ltoreq.V.sub.N2.ltoreq.5.0% by volume
(preferably 78.1% by volume)
[0090] 10% by volume.ltoreq.V.sub.O2.ltoreq.30% by volume
(preferably 21.0% by volume)
[0091] 0% by volume.ltoreq.V.sub.H2O.ltoreq.5% by volume
(preferably 2.5% by volume)
[0092] 0% by volume.ltoreq.V.sub.COz.ltoreq.0.1% by volume
(preferably 0.03% by volume)
[0093] However, z is 1 or 2, and air sometimes contains 0.1% by
volume or less of other impurity gases (hydrocarbon and the
like).
[0094] In such treatment, the film body 14a is burned in air to be
activated, and even when carbonate (MgCO.sub.3 or the like) and
hydroxide (Mg(OH).sub.2 or the like) of MgO or the like, which are
harmful to FPD, are formed on the surface of the film body 14a, the
carbonate (MgCO.sub.3 or the like) and hydroxide (Mg(OH).sub.2 or
the like) of MgO or the like on the surface of the film body 14a
are removed as CO.sub.2 and H.sub.2O. In this state, the fluoride
layer 14b is formed on the surface of the film body 14a to protect
the surface of the film body 14a by the fluoride layer 14b, thereby
preventing or suppressing the formation of the carbonate
(MgCO.sub.3 or the like) and hydroxide (Mg(OH).sub.2 or the like)
of MgO or the like.
[0095] In the above processing [a] and [b], burning is preferably
carried out in air to activate the film body 14a before, during or
after assembly of a panel using the substrate 13 on the surface of
which the film body 14a and the fluoride layer 14b are formed. The
burning temperature and air for burning in air are the same as
described above in [b].
[0096] Since the film body 14a is activated by this burning, even
when hydroxide (Mg(OH).sub.2 or the like) of MgO or the like are
formed a little on the film body 14a, the hydroxide (Mg(OH).sub.2
or the like) is removed as H.sub.2O, decreasing the rate of
recontamination of the film body 14a with atmospheric moisture.
[0097] FIGS. 3 and 4 show a second embodiment of the present
invention. In FIGS. 3 and 4, the same reference numerals as in
FIGS. 1 and 2 denote the same components.
[0098] In this embodiment, a film body 34a constituting a
protecting film 34 is formed on the surface of the front glass
substrate 13 with the display electrodes 16 and the transparent
dielectric layer 17 formed therebetween. The film body 34a is
formed by using a fluoride layer-coated powder of any one of MgO,
CaO, SrO, BaO, alkali earth compound oxides, rare earth oxides, and
compound oxides of alkali earth oxides and rare earth oxides. Like
in the first embodiment, the fluoride layer is represented by
MO.sub.XF.sub.Y (M is Mg, Ca, Sr, Ba, an alkali earth complex
metal, a rare earth metal, or a complex metal of an alkali earth
metal and a rare earth metal, 0.ltoreq.X<2, and
0<Y.ltoreq.4.) For example, the fluoride layer comprises a
MF.sub.2 layer, a MO.sub.0.5F layer, a MO.sub.0.25F.sub.1.5 layer,
a MF.sub.4 layer, a MOF.sub.2 layer, a MF.sub.3 layer, a MOF layer,
a MF.sub.2.66 layer or a MOF.sub.0.66 layer, or the like. The
fluoride layer 14b can be obtained by reaction of a gaseous
fluorinating agent with MgO, or the like. As the gaseous
fluorinating agent, any one of fluorine gas, hydrogen fluoride gas,
BF.sub.3, SbF.sub.5 and SF.sub.4, particularly, fluorine gas or
hydrogen fluoride gas, is preferably used. The thickness of the
fluoride layer is determined by a balance between improvement in
inhibition of reaction of MgO or the like and CO.sub.2 gas and
H.sub.2O gas, and the time of reaction of MgO or the like and the
gaseous fluorinating agent. The thickness of the fluoride layer 14b
is preferably in the range of 0.1 to 1000 nm, more preferably 0.1
to 100 nm. The reason for limiting the thickness of the fluoride
layer in the range of 0.1 to 1000 nm is that with a thickness of
over 1000 nm, the time of reaction of MgO or the like and the
gaseous fluorinating agent is increased to deteriorate workability.
The other construction is the same as the first embodiment.
[0099] The method of producing the PDP protecting film having the
above construction will be described.
[0100] [1] Formation of Film Body by Screen Printing
[0101] First, a powder of Any one of MgO, CaO, SrO, BaO, alkali
earth compound oxides, rare earth oxides, and compound oxides of
alkali earth oxides and rare earth oxides, which has an average
particle size of 50 to 2000 .ANG., is prepared. Next, the MgO
powder or the like is maintained in an atmosphere of a gaseous
fluorinating agent (temperature 10 to 100.degree. C.) for 0.1 to
120 minutes to modify the surfaces of the MgO powder or the like,
to form fluoride layers on the surfaces of the MgO powder or the
like. As the gaseous fluorinating agent, any one of fluorine gas,
hydrogen fluoride gas, BF.sub.3, SbF.sub.5 and SF.sub.4,
particularly, fluorine gas or hydrogen fluoride gas, is preferably
used. The pressure of the gaseous fluorinating agent is preferably
set in the range of 1 to 760 Torr, more preferably 10 to 300 Torr.
The reason for limiting the pressure of the gaseous fluorinating
agent in the range of 1 to 760 Torr is that control of the extent
of reaction, i.e., the thickness of the fluoride layer, is
facilitated.
[0102] Next, as shown in FIG. 3, electrode paste for the display
electrodes 16 composed of Ag or Au is coated on the surface of the
front glass substrate 13 at predetermined intervals by screen
printing, dried, and then burned. Then, transparent glass paste for
the transparent dielectric layer 17 is coated over the entire
surface of the front glass substrate 13 by screen printing,
followed by drying. Then, the MgO powder or the like (having the
surfaces coated with the fluoride layers), which constitutes the
film body 34a, a binder, and a solvent are mixed at predetermined
ratios to prepare paste for a film. The thus-prepared paste is
coated over the entire surface of the transparent dielectric layer
17 by screen printing, and dried. As the binder, alkoxide of an
alkali earth metal or rare earth metal, an organic acid compound,
acetylacetonate (for example, organic acid magnesium, magnesium
alkoxide, or magnesium acetylacetonate), ethyl cellulose, or ethyl
silicate can be used. As the solvent, .alpha.-terpineol, butyl
carbitol, butyl carbitol acetate, turpentine oil, or the like can
be used. The mixing ratios of the MgO powder or the like, the
binder, and the solvent are preferably set to 0.1 to 10% by weight,
10 to 99.9% by weight, and 0 to 30% by weight, respectively.
Furthermore, the front glass substrate 13 is dried by maintaining
in air at 100 to 200.degree. C. for 10 to 60 minutes, and then
burned by maintaining in air at 500 to 600.degree. C. for 10 to 60
minutes in air.
[0103] [2] Formation of Film Body by Spin Coating
[0104] First, the surfaces of a powder of any one of MgO, CaO, SrO,
BaO, alkali earth compound oxides, rare earth oxides, and compound
oxides of alkali earth oxides and rare earth oxides are coated with
fluoride layers in the same manner as described above in [1]. Next,
electrode paste and dielectric layer paste are coated on the
surface of the front glass substrate, dried and burned. Then, the
MgO powder or the like (having the surfaces coated with the
fluoride layers), which constitutes the film body, a binder, and a
solvent are mixed at predetermined ratios to prepare a dispersion
for a film. The thus-prepared dispersion is coated over the entire
surface of the transparent dielectric layer by spin coating, and
dried. As the binder, alkoxide of an alkali earth metal or rare
earth metal, an organic acid compound, acetylacetonate (for
example, magnesium alkoxide, organic acid magnesium, magnesium
acetylacetonate, magnesium trifluoroacetate, magnesium
trifluoroacetylacetonate, or magnesium hexafluoroacetylacetonate),
ethyl silicate, or the like can be used. As the solvent, an
alcohol, cellosolve, or the like can be used. The mixing ratios of
the MgO powder or the like, the binder, and the solvent are
preferably set to 1 to 40% by weight, 0.1 to 10% by weight, and 55
to 98.9% by weight, respectively. Furthermore, the front glass
substrate is dried by maintaining in air at 40 to 100.degree. C.
for 5 to 60 minutes, and then burned by maintaining in air at 500
to 600.degree. C. for 10 to 60 minutes.
[0105] Since the PDP protecting film produced by the
above-described method comprises the film body 34a composed of the
MgO powder or the like, the surfaces of which are coated with the
fluoride layers, MgO or the like in the film body 34a little reacts
with CO.sub.2 gas and H.sub.2O gas in air even when the film body
34a is exposed to air for a long time during the process for
manufacturing the PDP 10. As a result, the MgO powder or the like
in the film body 34a is little degenerated to MgCO.sub.3,
Mg(OH).sub.2, etc. which have the probability of deteriorating the
function of the PDP 10, thereby improving the environment
resistance of the film body 34a.
[0106] Furthermore, the MgO powder or the like in the film body 34a
is little degenerated to MgCO.sub.3 and Mg(OH).sub.2, thereby
shortening the time of the subsequent degassing step for removing
MgCO.sub.3 and Mg(OH).sub.2 or omitting the subsequent degassing
step to decrease the manufacturing cost of the PDP 10.
[0107] Furthermore, the fluoride layers coated on the surfaces of
the MgO powder or the like are very thin, and thus the MgO powder
or the like has substantially the same mechanical properties as a
MgO powder or the like without the fluoride layer.
[0108] FIG. 5 shows a third embodiment of the present invention. In
FIG. 5, the same reference numerals as FIGS. 1 and 2 denote the
same components.
[0109] In this embodiment, a protecting film 54 is composed of an
alkali earth metal oxide, an alkali earth metal compound oxide, a
rare earth metal oxide, or a compound oxide of an alkali earth
metal and rare earth metal. Examples of alkali earth metal oxides
include MgO, CaO, SrO, and BaO; and examples of alkali earth metal
compound oxides include (Ca, Sr)O, (Mg, Sr)O, and (Sr, Ba)O.
Examples of rare earth metal oxides include Y.sub.2O.sub.3,
Gd.sub.2O.sub.3, Dy.sub.2O.sub.3, Yb.sub.2O.sub.3, Nd.sub.2O.sub.3,
Ho.sub.2O.sub.3, Er.sub.2O.sub.3, La.sub.2O.sub.3, Sc.sub.2O.sub.3,
CeO.sub.2, Pr.sub.6O.sub.11, Sm.sub.2O.sub.3, Eu.sub.2O.sub.3,
Tb.sub.4O.sub.7, Tm.sub.2O.sub.3, and Lu.sub.2O.sub.3. Examples of
compound oxides of alkali earth metals and rare earth metals
include MRe.sub.2O.sub.4 (M is an alkali earth metal such as Mg,
Ca, Sr or Ba, and Re is a rare earth metal such as Gd, Y or La),
alkali earth metal oxide mixtures containing several molar % of
rare earth metal compound [MO:Re.sub.2O.sub.3 (for example,
MgO:La.sub.2O.sub.3, MgO:Sc.sub.2O.sub.3, MgO:Y.sub.2O.sub.3, and
the like)], and the like.
[0110] A fluoride layer 55 is formed on the surface of the
protecting film 54. The fluoride layer 55 is removed after PDP is
assembled by using the protecting film 54 on which the fluoride
layer 55 is formed. The fluoride layer 55 is represented by
MO.sub.XF.sub.Y (wherein M is an alkali earth metal, an alkali
earth complex metal, a rare earth metal, or a complex metal of an
alkali earth metal and a rare earth metal, 0.ltoreq.X<2, and
0<Y.ltoreq.4). Examples of alkali earth metals include Mg, Ca,
Sr, and Ba; and examples of alkali earth complex metals include
(Ca, Sr), (Mg, Sr), and (Sr, Ba). Examples of rare earth metals
include Y, Gd, Dy, Yb, Nd, Ho, Er, La, Sc, Ce, Pr, Sm, Eu, Tb, Tm,
and Lu. Examples of compounds of alkali earth metals and rare earth
metals include MRe (M is an alkali earth metal such as Mg, Ca, Sr
or Ba, and Re is a rare earth metal such as Gd, Y or La), alkali
earth metal mixtures containing several molar % of rare earth metal
[MO:Re (for example, Mg:La, Mg:Sc, Mg:Y, and the like)], and the
like.
[0111] Examples of the fluoride layer include a MF.sub.2 layer, a
MO.sub.0.5F layer, a MO.sub.0.25F.sub.1.5 layer, a MF.sub.4 layer,
a MOF.sub.2 layer, a MF.sub.3 layer, a MOF layer, a MF.sub.2.66
layer and a MOF.sub.0.66 layer. The fluoride layer 55 can be
obtained by reaction of a gaseous fluorinating agent and MgO which
forms the protecting film 34. As the gaseous fluorinating agent,
any one of fluorine gas, hydrogen fluoride gas, BF.sub.3, SbF.sub.5
and SF.sub.4, particularly, fluorine gas or hydrogen fluoride gas,
is preferably used from the viewpoint of the degree of reactivity
and versatility of the gaseous fluorinating agent. The thickness of
the fluoride layer 55 is determined by a balance between
improvement in inhibition of reaction of a alkali earth metal oxide
or the like and CO.sub.2 gas and water vapor, and the time of
reaction of an alkali earth metal oxide or the like and the gaseous
fluorinating agent. The thickness of the fluoride layer 55 is
preferably in the range of 0.1 to 1000 nm, more preferably 0.1 to
100 nm. The reason for limiting the thickness of the fluoride layer
55 in the range of 0.1 to 1000 nm is that with a thickness of over
1000 nm, the time of reaction of a alkali earth metal oxide or the
like and the gaseous fluorinating agent is increased to deteriorate
workability.
[0112] The method of producing the PDP protecting film constructed
as described above will be described.
[0113] [1] Formation of Protecting Film by Evaporation
[0114] First, as shown in FIG. 5(a), electrode paste for the
display electrodes 16 composed of Ag or Au is coated on the surface
of the front glass substrate 13 at predetermined intervals by
screen printing, dried, and then burned. Then, transparent glass
paste for the transparent dielectric layer 17 is coated over the
entire surface of the front glass substrate 13 by screen printing,
followed by drying. The front glass substrate 13 is dried by
maintaining in air at 100 to 200.degree. C. for 10 to 60 minutes,
and then burned by maintaining in air at 500 to 600.degree. C. for
10 to 60 minutes.
[0115] Next, sintered pellets of an alkali earth metal oxide or the
like (for example, MgO), which has a purity of 99.5% or more, are
deposited by vaporization such as electron beam evaporation or the
like to cover the surface of the transparent dielectric layer 17 of
the glass substrate 13, to form the protecting film 54 (FIG. 5(a)).
Deposition conditions of the protecting film 54 preferably include
an acceleration voltage of 5 to 30 kV, a deposition pressure of
0.1.times.10.sup.-2 to 10.times.10.sup.-2 Pa, and a deposition
distance of 100 to 1000 nm. The front glass substrate 13 is further
maintained in an atmosphere of a gaseous fluorinating agent
(temperature 10 to 100.degree. C.) for 0.1 to 120 minutes to modify
the surface of the protecting film 54, to form the fluoride layer
55 on the surface of the protecting film 54 (FIG. 5(b). The
pressure of the gaseous fluorinating agent is preferably set in the
range of 1 to 760 Torr, more preferably in the range of 10 to 300
Torr. The reason for limiting the pressure of the gaseous
fluorinating agent in the range of 1 to 760 Torr is that control of
the extent of reaction, i.e., control of the thickness of the
fluoride layer, is facilitated.
[0116] After the glass substrate 13 is incorporated in the PDP 10
(FIG. 5(c)), and a removal discharge gas is injected in each of the
cells 18 of the PDP 10, a predetermined voltage is applied between
the display electrodes 16 to start surface discharge so that the
fluoride layer 55 is removed by etching due to the discharge (FIG.
5(d)). Furthermore, the removal discharge gas is exhausted from
each of the cells 18, and then a display discharge gas is sealed in
each of the cells 18. The fluoride layer 55 is preferably removed
by plasma etching using a fluorine-containing gas such as CF.sub.6,
SF.sub.6, or the like as the removal discharge gas. After removal
processing of the fluoride layer 55, in some cases, the fluoride
layer 55 having substantially the same area as the upper sides of
the partition walls partially remains between the partition walls
and the protecting film (FIG. 5(d)).
[0117] [2] Formation of Protecting Film by Sputtering
[0118] First, a glass substrate with electrodes is produced by the
same method as described above in [1], and then a protecting film
is formed on the glass substrate by sputtering using a MgO target
having a 5-inch size and a purity of 99.5% or more to cover the
surface of the transparent dielectric layer. The deposition
conditions of the protecting film preferably include a
radio-frequency output of 1 kW, a sputtering pressure of 0.50 to
3.0 Pa, an oxygen concentration of 5 to 50% based on argon gas, and
a substrate temperature of 20 to 300.degree. C.
[0119] Then, the protecting film is maintained in an atmosphere of
the gaseous fluorinating agent to modify the surface thereof by the
same method as described above in [1], to form a fluoride layer on
the surface of the protecting film. Furthermore, after the glass
substrate is incorporated in PDP, the fluoride layer is
removed.
[0120] [3] Formation of Protecting Film by Screen Printing
[0121] A powder of an alkali earth metal oxide or the like (for
example, MgO), which has an average particle size of 50 to 2000
.ANG., is previously prepared by a vapor phase or liquid synthetic
method. First, electrode paste for the display electrodes composed
of Ag or Au is coated on the surface of the front glass substrate
at predetermined intervals by screen printing, dried, and then
burned. Then, transparent glass paste for the transparent
dielectric layer is coated over the entire surface of the front
glass substrate by screen printing, followed by drying. Then, the
powder which. constitutes the protecting film, a binder, and a
solvent are mixed at predetermined ratios to prepare paste. The
thus-prepared paste is coated over the entire surface of the
transparent dielectric layer by screen printing, and dried.
[0122] As the binder, organic acid magnesium, magnesium alkoxide,
or magnesium acetylacetonate, ethyl cellulose, or ethyl silicate
can be used. As the solvent, .alpha.-terpineol, butyl carbitol,
butyl carbitol acetate, turpentine oil, or the like can be used.
The mixing ratios of the powder, the binder, and the solvent are
preferably set to 0 to 10% by weight, 10 to 100% by weight, and 0
to 30% by weight, respectively.
[0123] The front glass substrate is dried by maintaining in air at
100 to 200.degree. C. for 10 to 60 minutes, and then burned by
maintaining in air at 500 to 600.degree. C. for 10 to 60 minutes.
The front glass substrate is further maintained in an atmosphere of
a gaseous fluorinating agent in the same manner as described above
in [1] to modify the surface of the protecting film, to form a
fluoride layer on the surface of the protecting film. After the
glass substrate is incorporated in PDP, the fluoride layer is
removed.
[0124] [4] Formation of Protecting Film by Spin Coating
[0125] Electrode paste and dielectric layer are coated on the
surface of the front glass, dried and then burned by the same
method as described above in [3]. Then, a powder of an alkali earth
metal oxide or the like (for example, MgO), which constitutes the
protecting film, a binder, and a solvent are mixed at predetermined
ratios to prepare a dispersion. The thus-prepared dispersion is
deposited over the entire surface of the transparent dielectric
layer by spin coating, and dried. As the binder, magnesium
alkoxide, an organic acid compound, acetylacetonate, ethyl
silicate, or the like can be used. As the solvent, an alcohol,
cellosolve, or the like can be used. The mixing ratios of the MgO
powder, the binder, and the solvent are preferably set to 0 to 40%
by weight, 0.1 to 10% by weight, and 55 to 99.9% by weight,
respectively. The front glass substrate is dried by maintaining in
air at 40 to 100.degree. C. for 5 to 60 minutes, and then burned by
maintaining in air at 500 to 600.degree. C. for 10 to 60 minutes.
The front glass substrate is further maintained in an atmosphere of
a gaseous fluorinating agent in the same manner as described above
in [1] to modify the surface of the protecting film, to form a
fluoride layer on the surface of the protecting film. After the
glass substrate is incorporated in PDP, the fluoride layer is
removed.
[0126] Since the PDP protecting film produced by the
above-described method has the surface coated with the fluoride
layer 55, the protecting film 54 little reacts with CO.sub.2 gas
and H.sub.2O gas in air even when the protecting film 54 is exposed
to air for a long time during the process for manufacturing the PDP
10. As a result, the protecting film 54 is little degenerated to
MgCO.sub.3, Mg(OH).sub.2, etc. which have the probability of
deteriorating the function of the PDP 10, thereby improving the
environment resistance of the protecting film 54.
[0127] In addition, since the fluoride layer 55 is formed by direct
reaction between the protecting film 54 and the gaseous
fluorinating agent, the fluoride layer 55 and the protecting film
54 have good matching therebetween. Therefore, it is possible to
prevent the occurrence of cracking in the fluoride layer 55, and
separation of the fluoride layer 55, and improve the degeneration
protecting effect of the protecting film 54.
[0128] Furthermore, since the fluoride layer 55 is removed after
the glass substrate 13 produced by the above-described method is
incorporated in the PDP 10, discharge characteristics of the PDP 10
can be improved.
[0129] Although the first to third embodiments relate to PDP as
FPD, PALC or the like may be used as long as a protecting film is
formed on the surface of a front glass substrate.
[0130] Examples and comparative examples of the present invention
will be described in detail below.
EXAMPLE 1
[0131] First, display electrodes (thickness of 5 .mu.m) made of Ag
were formed on a front glass substrate having a thickness of 3 mm
by screen printing, and then a transparent dielectric layer
(thickness of 20 .mu.m) made of glass was formed thereon by screen
printing, as shown in FIG. 1. Next, the glass substrate was dried
by maintaining in air at 150.degree. C. for 30 minutes, and then
burned by maintaining in air at 550.degree. C. for 30 minutes.
[0132] Next, using MgO sintered pellets having a purity of 99.8%,
MgO films were deposited by electron beam evaporation to cover the
surface of the transparent dielectric layer of the glass substrate
to form a film body. The deposition conditions for the film body
included an acceleration voltage of 15 kV, a deposition pressure of
1.times.10.sup.-2 Pa, a deposition distance of 600 mm. The glass
substrate was further maintained in a F.sub.2 gas atmosphere
(temperature 25.degree. C.) at pressure of 152 Torr for 10 minutes
to modify the surface of the film body, to form the fluoride layer
on the surface of the film body. The thus-formed glass substrate
was referred to as "Example 1".
EXAMPLE 2
[0133] A film body was formed on the surface of a glass substrate
by electron beam evaporation in the same manner as Example 1, and
then the glass substrate was maintained in a F.sub.2 gas atmosphere
(temperature 25.degree. C.) at pressure of 72 Torr for 10 minutes
to modify the surface of the film body, to form a fluoride layer on
the surface of the film body. The thus-formed glass substrate was
referred to as "Example 2".
EXAMPLE 3
[0134] A film body was formed on the surface of a glass substrate
by electron beam evaporation in the same manner as Example 1, and
then the glass substrate was maintained in a F.sub.2 gas atmosphere
(temperature 25.degree. C.) at pressure of 38 Torr for 1 minute to
modify the surface of the film body, to form a fluoride layer on
the surface of the film body. The thus-formed glass substrate was
referred to as "Example 3".
EXAMPLE 4
[0135] A film body was formed on the surface of a glass substrate
by electron beam evaporation in the same manner as Example 1, and
then the glass substrate was maintained in a F.sub.2 gas atmosphere
(temperature 25.degree. C.) at pressure of 38 Torr for 10 minutes
to modify the surface of the film body, to form a fluoride layer on
the surface of the film body. The thus-formed glass substrate was
referred to as "Example 4".
EXAMPLE 5
[0136] A film body was formed on the surface of a glass substrate
by electron beam evaporation in the same manner as Example 1, and
then the glass substrate was maintained in a F.sub.2 gas atmosphere
(temperature 25.degree. C.) at pressure of 38 Torr for 60 minutes
to modify the surface of the film body, to form a fluoride layer on
the surface of the film body. The thus-formed glass substrate was
referred to as "Example 5".
EXAMPLE 6
[0137] A film body was formed on the surface of a glass substrate
by electron beam evaporation in the same manner as Example 1, and
then the glass substrate was maintained in a F.sub.2 gas atmosphere
(temperature 25.degree. C.) at pressure of 7.6 Torr for 10 minutes
to modify the surface of the film body, to form a fluoride layer on
the surface of the film body. The thus-formed glass substrate was
referred to as "Example 6".
EXAMPLE 7
[0138] A film body was formed on the surface of a glass substrate
by electron beam evaporation by the same manner as Example 1, and
then the glass substrate was maintained in an atmosphere
(temperature 25.degree. C.) a gas mixture containing F.sub.2 gas at
partial pressure of 7.6 Torr and N.sub.2 gas at partial pressure of
752 Torr for 10 minutes to modify the surface of the film body, to
form a fluoride layer on the surface of the film body. The
thus-formed glass substrate was referred to as "Example 7".
EXAMPLE 8
[0139] A film body was formed on the surface of a glass substrate
by electron beam evaporation in the same manner as Example 1, and
then the glass substrate was maintained in a F.sub.2 gas atmosphere
(temperature 100.degree. C.) at pressure of 7.6 Torr for 10 minutes
to modify the surface of the film body, to form a fluoride layer on
the surface of the film body. The thus-formed glass substrate was
referred to as "Example 8".
EXAMPLE 9
[0140] A film body was formed on the surface of a glass substrate
by electron beam evaporation in the same manner as Example 1, and
then the glass substrate was maintained in a HF gas atmosphere
(temperature 25.degree. C.) at pressure of 38 Torr for 1 minute to
modify the surface of the film body, to form a fluoride layer on
the surface of the film body. The thus-formed glass substrate was
referred to as "Example 9".
EXAMPLE 10
[0141] A film body was formed on the surface of a glass substrate
by electron beam evaporation in the same manner as Example 1, and
then the glass substrate was maintained in an atmosphere
(temperature 25.degree. C.) of a gas mixture containing HF gas at
partial pressure of 7.6 Torr and N.sub.2 gas at partial pressure of
752 Torr for 10 minutes to modify the surface of the film body, to
form a fluoride layer on the surface of the film body. The
thus-formed glass substrate was referred to as "Example 10".
EXAMPLE 11
[0142] A film body was formed on the surface of a glass substrate
by electron beam evaporation in the same manner as Example 1, and
then the glass substrate was maintained in a BF.sub.3 gas
atmosphere (temperature 25.degree. C.) at pressure of 7.6 Torr for
10 minutes to modify the surface of the film body, to form a
fluoride layer on the surface of the film body. The thus-formed
glass substrate was referred to as "Example 11".
EXAMPLE 12
[0143] A film body was formed on the surface of a glass substrate
by electron beam evaporation in the same manner as Example 1, and
then the glass substrate was maintained in a SbF.sub.5 gas
atmosphere (temperature 25.degree. C.) at pressure of 7.6 Torr for
10 minutes to modify the surface of the film body, to form a
fluoride layer on the surface of the film body. The thus-formed
glass substrate was referred to as "Example 12".
EXAMPLE 13
[0144] A film body was formed on the surface of a glass substrate
by electron beam evaporation in the same manner as Example 1, and
then the glass substrate was maintained in a SF.sub.4 gas
atmosphere (temperature 25.degree. C.) at pressure of 7.6 Torr for
10 minutes to modify the surface of the film body, to form a
fluoride layer on the surface of the film body. The thus-formed
glass substrate was referred to as "Example 13".
EXAMPLE 14
[0145] A glass substrate with electrodes was formed by the same
method as Example 1, and then a transparent dielectric film was
coated on the glass substrate by sputtering using a 5-inch size MgO
target having a purity of 99.99% (4N) to form a film body. The
deposition conditions for the film body preferably included a
radio-frequency output of 1 kW, a sputtering pressure of 1.33 Pa,
an oxygen concentration of 10% relative to argon gas, and a
substrate temperature of 150.degree. C.
[0146] The glass substrate was maintained in a F.sub.2 gas
atmosphere by the same method as Example 1 to modify the surface of
the film body, to form a fluoride layer on the surface of the film
body. The thus-formed glass substrate was referred to as "Example
14".
EXAMPLE 15
[0147] A film body was formed on the surface of a glass substrate
by sputtering in the same manner as Example 14, and then the glass
substrate was maintained in a F.sub.2 gas atmosphere (temperature
25.degree. C.) at pressure of 72 Torr for 10 minutes to modify the
surface of the film body, to form a fluoride layer on the surface
of the film body. The thus-formed glass substrate was referred to
as "Example 15".
EXAMPLE 16
[0148] A film body was formed on the surface of a glass substrate
by sputtering in the same manner as Example 14, and then the glass
substrate was maintained in a F.sub.2 gas atmosphere (temperature
25.degree. C.) at pressure of 38 Torr for 1 minute to modify the
surface of the film body, to form a fluoride layer on the surface
of the film body. The thus-formed glass substrate was referred to
as "Example 16".
EXAMPLE 17
[0149] A film body was formed on the surface of a glass substrate
by sputtering in the same manner as Example 14, and then the glass
substrate was maintained in a F.sub.2 gas atmosphere (temperature
25.degree. C.) at pressure of 38 Torr for 10 minutes to modify the
surface of the film body, to form a fluoride layer on the surface
of the film body. The thus-formed glass substrate was referred to
as "Example 17".
EXAMPLE 18
[0150] A film body was formed on the surface of a glass substrate
by sputtering in the same manner as Example 14, and then the glass
substrate was maintained in a F.sub.2 gas atmosphere (temperature
25.degree. C.) at pressure of 38 Torr for 60 minutes to modify the
surface of the film body, to form a fluoride layer on the surface
of the film body. The thus-formed glass substrate was referred to
as "Example 18".
EXAMPLE 19
[0151] A film body was formed on the surface of a glass substrate
by sputtering in the same manner as Example 14, and then the glass
substrate was maintained in a F.sub.2 gas atmosphere (temperature
25.degree. C.) at pressure of 7.6 Torr for 10 minutes to modify the
surface of the film body, to form a fluoride layer on the surface
of the film body. The thus-formed glass substrate was referred to
as "Example 19".
EXAMPLE 20
[0152] A film body was formed on the surface of a glass substrate
by sputtering in the same manner as Example 14, and then the glass
substrate was maintained in an atmosphere (temperature 25.degree.
C.) a gas mixture containing F.sub.2 gas at pressure of 7.6 Torr
and N2 gas at pressure of 752 Torr for 10 minutes to modify the
surface of the film body, to form a fluoride layer on the surface
of the film body. The thus-formed glass substrate was referred to
as "Example 20".
EXAMPLE 21
[0153] A film body was formed on the surface of a glass substrate
by sputtering in the same manner as Example 14, and then the glass
substrate was maintained in a F.sub.2 gas atmosphere (temperature
100.degree. C.) at pressure of 7.6 Torr for 10 minutes to modify
the surface of the film body, to form a fluoride layer on the
surface of the film body. The thus-formed glass substrate was
referred to as "Example 21".
EXAMPLE 22
[0154] A film body was formed on the surface of a glass substrate
by sputtering in the same manner as Example 14, and then the glass
substrate was maintained in a HF gas atmosphere (temperature
25.degree. C.) at pressure of 38 Torr for 1 minute to modify the
surface of the film body, to form a fluoride layer on the surface
of the film body. The thus-formed glass substrate was referred to
as "Example 22".
EXAMPLE 23
[0155] A film body was formed on the surface of a glass substrate
by sputtering in the same manner as Example 14, and then the glass
substrate was maintained in an atmosphere (temperature 25.degree.
C.) of a gas mixture containing HF gas at pressure of 7.6 Torr and
N.sub.2 gas at pressure of 752 Torr for 10 minutes to modify the
surface of the film body, to form a fluoride layer on the surface
of the film body. The thus-formed glass substrate was referred to
as "Example 23".
EXAMPLE 24
[0156] First, display electrodes (thickness of 5 .mu.m) made of Ag
were formed on a front glass substrate having a thickness of 3 mm
by screen printing, and then a transparent dielectric layer
(thickness of 20 .mu.m) made of glass was formed thereon by screen
printing. Next, 79% by weight of organic acid magnesium (Magnesium
Naphthenate, produced by Nihon Kagaku Sangyo Co., Ltd.) as a binder
containing a MgO component, 2% by weight of ethyl cellulose as a
binder containing no MgO component, and 19% by weight of
.alpha.-terpineol as a solvent were mixed to prepare paste for a
film. The thus-prepared paste was coated on the glass substrate by
screen printing to form a film body.
[0157] Next, the glass substrate was dried by maintaining at
150.degree. C. in air for 30 minutes, and then burned by
maintaining at 550.degree. C. in air for 30 minutes. Furthermore,
the glass substrate was maintained in a F.sub.2 gas atmosphere
(temperature 25.degree. C.) at pressure of 152 Torr for 10 minutes
to modify the surface of the film body, to form a fluoride layer on
the surface of the film body. The thus-formed glass substrate was
referred to as "Example 24".
EXAMPLE 25
[0158] A film body was formed on the surface of a glass substrate
by screen printing in the same manner as Example 24, dried and then
burned. Then the glass substrate was maintained in a F.sub.2 gas
atmosphere (temperature 25.degree. C.) at pressure of 72 Torr for
10 minutes to modify the surface of the film body, to form a
fluoride layer on the surface of the film body. The thus-formed
glass substrate was referred to as "Example 25".
EXAMPLE 26
[0159] A film body was formed on the surface of a glass substrate
by screen printing in the same manner as Example 24, dried and then
burned. Then the glass substrate was maintained in a F.sub.2 gas
atmosphere (temperature 25.degree. C.) at pressure of 38 Torr for 1
minute to modify the surface of the film body, to form a fluoride
layer on the surface of the film body. The thus-formed glass
substrate was referred to as "Example 26".
EXAMPLE 27
[0160] A film body was formed on the surface of a glass substrate
by screen printing in the same manner as Example 24, dried and then
burned. Then the glass substrate was maintained in a F.sub.2 gas
atmosphere (temperature 25.degree. C.) at pressure of 38 Torr for
10 minutes to modify the surface of the film body, to form a
fluoride layer on the surface of the film body. The thus-formed
glass substrate was referred to as "Example 27".
EXAMPLE 28
[0161] A film body was formed on the surface of a glass substrate
by screen printing in the same manner as Example 24, dried and then
burned. Then the glass substrate was maintained in a F.sub.2 gas
atmosphere (temperature 25.degree. C.) at pressure of 38 Torr for
60 minutes to modify the surface of the film body, to form a
fluoride layer on the surface of the film body. The thus-formed
glass substrate was referred to as "Example 28".
EXAMPLE 29
[0162] A film body was formed on the surface of a glass substrate
by screen printing in the same manner as Example 24, dried and then
burned. Then the glass substrate was maintained in a F.sub.2 gas
atmosphere (temperature 25.degree. C.) at pressure of 7.6 Torr for
10 minutes to modify the surface of the film body, to form a
fluoride layer on the surface of the film body. The thus-formed
glass substrate was referred to as "Example 29".
EXAMPLE 30
[0163] A film body was formed on the surface of a glass substrate
by screen printing in the same manner as Example 24, dried and then
burned. Then the glass substrate was maintained in an atmosphere
(temperature 25.degree. C.) of a gas mixture containing F.sub.2 gas
at pressure of 7.6 Torr and N.sub.2 gas at pressure of 752 Torr for
10 minutes to modify the surface of the film body, to form a
fluoride layer on the surface of the film body. The thus-formed
glass substrate was referred to as "Example 30".
EXAMPLE 31
[0164] A film body was formed on the surface of a glass substrate
by screen printing in the same manner as Example 24, dried and then
burned. Then the glass substrate was maintained in a F.sub.2 gas
atmosphere (temperature 100.degree. C.) at pressure of 7.6 Torr for
10 minutes to modify the surface of the film body, to form a
fluoride layer on the surface of the film body. The thus-formed
glass substrate was referred to as "Example 31".
EXAMPLE 32
[0165] A film body was formed on the surface of a glass substrate
by screen printing in the same manner as Example 24, dried and then
burned. Then the glass substrate was maintained in a HF gas
atmosphere (temperature 25.degree. C.) at pressure of 38 Torr for 1
minute to modify the surface of the film body, to form a fluoride
layer on the surface of the film body. The thus-formed glass
substrate was referred to as "Example 32".
EXAMPLE 33
[0166] A film body was formed on the surface of a glass substrate
by screen printing in the same manner as Example 24, dried and then
burned. Then the glass substrate was maintained in an atmosphere
(temperature 25.degree. C.) of a gas mixture containing HF gas at
pressure of 7.6 Torr and N.sub.2 gas at pressure of 752 Torr for 10
minutes to modify the surface of the film body, to form a fluoride
layer on the surface of the film body. The thus-formed glass
substrate was referred to as "Example 33".
EXAMPLE 34
[0167] 5% by weight of MgO powder (produced by Ube Materials)
produced by a vapor phase method and having an average particle
size of 100 .ANG., 79% by weight of organic acid magnesium
(Magnesium Naphthenate, produced by Nihon Kagaku Sangyo Co., Ltd.)
as a binder for a MgO component, 2% by weight of ethyl cellulose,
and 18% by weight of .alpha.-terpineol as a solvent were mixed to
prepare powder-containing paste for a film. The thus-prepared paste
for a film containing a MgO powder was used for forming a film body
on the glass substrate by the same method as Example 24. Next, the
surface of the film body was modified to form a fluoride layer on
the surface thereof. The thus-formed glass substrate was referred
to as "Example 34".
EXAMPLE 35
[0168] First, the display electrodes 16 (thickness of 5 .mu.m) made
of Ag were formed on the front glass substrate 13 having a
thickness of 3 mm by screen printing, and then the transparent
dielectric layer 17 (thickness of 20 .mu.m) made of glass was
formed thereon by screen printing. Next, 1.25% by weight of
magnesium ethoxide as a binder containing a MgO component, and
98.75% by weight of methyl cellosolve as a solvent were mixed to
prepare a uniform coating solution for a film. The thus-prepared
coating solution was coated on the glass substrate by spin coating
to form a film body.
[0169] Next, the glass substrate 13 was dried by maintaining at
60.degree. C. in air for 30 minutes, and then burned by maintaining
at 580.degree. C. in air for 10 minutes. Furthermore, the glass
substrate was maintained in a F.sub.2 gas atmosphere (temperature
25.degree. C.) at pressure of 152 Torr for 10 minutes to modify the
surface of the film body, to form a fluoride layer on the surface
of the film body. The thus-formed glass substrate was referred to
as "Example 35".
EXAMPLE 36
[0170] A film body was formed on the surface of a glass substrate
by spin coating in the same manner as Example 35, dried and then
burned. Then the glass substrate was maintained in a F.sub.2 gas
atmosphere (temperature 25.degree. C.) at pressure of 72 Torr for
10 minutes to modify the surface of the film body, to form a
fluoride layer on the surface of the film body. The thus-formed
glass substrate was referred to as "Example 36".
EXAMPLE 37
[0171] A film body was formed on the surface of a glass substrate
by spin coating in the same manner as Example 35, dried and then
burned. Then the glass substrate was maintained in a F.sub.2 gas
atmosphere (temperature 25.degree. C.) at pressure of 38 Torr for 1
minute to modify the surface of the film body, to form a fluoride
layer on the surface of the film body. The thus-formed glass
substrate was referred to as "Example 37".
EXAMPLE 38
[0172] A film body was formed on the surface of a glass substrate
by spin coating in the same manner as Example 35, dried and then
burned. Then the glass substrate was maintained in a F.sub.2 gas
atmosphere (temperature 25.degree. C.) at pressure of 38 Torr for
10 minutes to modify the surface of the film body, to form a
fluoride layer on the surface of the film body. The thus-formed
glass substrate was referred to as "Example 38".
EXAMPLE 39
[0173] A film body was formed on the surface of a glass substrate
by spin coating in the same manner as Example 35, dried and then
burned. Then the glass substrate was maintained in a F.sub.2 gas
atmosphere (temperature 25.degree. C.) at pressure of 38 Torr for
60 minutes to modify the surface of the film body, to form a
fluoride layer on the surface of the film body. The thus-formed
glass substrate was referred to as "Example 39".
EXAMPLE 40
[0174] A film body was formed on the surface of a glass substrate
by spin coating in the same manner as Example 35, dried and then
burned. Then the glass substrate was maintained in a F.sub.2 gas
atmosphere (temperature 25.degree. C.) at pressure of 7.6 Torr for
10 minutes to modify the surface of the film body, to form a
fluoride layer on the surface of the film body. The thus-formed
glass substrate was referred to as "Example 40".
EXAMPLE 41
[0175] A film body was formed on the surface of a glass substrate
by spin coating in the same manner as Example 35, dried and then
burned. Then the glass substrate was maintained in an atmosphere
(temperature 25.degree. C.) of a gas mixture containing F.sub.2 gas
at partial pressure of 7.6 Torr and N.sub.2 gas at partial pressure
of 752 Torr for 10 minutes to modify the surface of the film body,
to form a fluoride layer on the surface of the film body. The
thus-formed glass substrate was referred to as "Example 41".
EXAMPLE 42
[0176] A film body was formed on the surface of a glass substrate
by spin coating in the same manner as Example 35, dried and then
burned. Then the glass substrate was maintained in a F.sub.2 gas
atmosphere (temperature 100.degree. C.) at pressure of 7.6 Torr for
10 minutes to modify the surface of the film body, to form a
fluoride layer on the surface of the film body. The thus-formed
glass substrate was referred to as "Example 42".
EXAMPLE 43
[0177] A film body was formed on the surface of a glass substrate
by spin coating in the same manner as Example 35, dried and then
burned. Then the glass substrate was maintained in a HF gas
atmosphere (temperature 25.degree. C.) at pressure of 38 Torr for 1
minute to modify the surface of the film body, to form a fluoride
layer on the surface of the film body. The thus-formed glass
substrate was referred to as "Example 43".
EXAMPLE 44
[0178] A film body was formed on the surface of a glass substrate
by spin coating in the same manner as Example 35, dried and then
burned. Then the glass substrate was maintained in an atmosphere
(temperature 25.degree. C.) of a gas mixture containing HF gas at
partial pressure of 7.6 Torr and N.sub.2 gas at partial pressure of
752 Torr for 10 minutes to modify the surface of the film body, to
form a fluoride layer on the surface of the film body. The
thus-formed glass substrate was referred to as "Example 44".
EXAMPLE 45
[0179] 5% by weight of MgO powder (produced by Ube Materials)
produced by a vapor phase method and having an average particle
size of 100 .ANG., 1.25% by weight of magnesium diethoxide as a
binder for a MgO component, 2% by weight of ethyl cellulose, and
92.75% by weight of methyl cellosolve as a solvent were mixed to
prepare a uniform coating solution for a film containing MgO
powder. The thus-prepared coating solution was used for forming a
film body on a glass substrate by the same method as Example 35.
Next, the surface of the film body was modified to form a fluoride
layer on the surface thereof. The thus-formed glass substrate was
referred to as "Example 45".
EXAMPLE 46
[0180] 5 g of MgO powder (produced by Ube Materials) produced by a
vapor phase method and having an average particle size of 100 .ANG.
was maintained in a F.sub.2 gas atmosphere (temperature 25.degree.
C.) at pressure of 152 Torr for 10 minutes to modify the surface of
the MgO powder, to coat the surface of the MgO powder with a
fluoride layer. The MgO powder was referred to as MgO powder of
Example 46.
[0181] On the other hand, display electrodes (thickness of 5 .mu.m)
made of Ag were formed on a front glass substrate having a
thickness of 3 mm by screen printing, and then a transparent
dielectric layer (thickness of 20 .mu.m) made of glass was formed
thereon by screen printing. Next, 5% by weight of MgO powder with
the surface coated with a fluoride layer, 75% by weight of organic
acid magnesium (Magnesium Naphthenate, produced by Nihon Kagaku
Sangyo Co., Ltd.) and 2% by weight of ethyl cellulose as a binder,
and 18% by weight of .alpha.-terpineol as a solvent were mixed to
prepare paste for a film. The thus-prepared paste for a film was
coated on the glass substrate by screen printing to form a film
body. Furthermore, the glass substrate was dried by maintaining at
150.degree. C. in air for 30 minutes, and then burned by
maintaining at 580.degree. C. in air for 10 minutes. The
thus-formed glass substrate was referred to as "Example 46".
EXAMPLE 47
[0182] The same MgO powder as Example 46 was maintained in a
F.sub.2 gas atmosphere (temperature 25.degree. C.) at pressure of
72 Torr for 10 minutes to form a fluoride layer on the surface of
the MgO powder. The MgO powder was used for forming a film body on
a glass substrate by the same method as Example 46. The MgO powder
having the surface coated with the fluoride layer, and the glass
substrate were referred to as "Example 47".
EXAMPLE 48
[0183] The same MgO powder as Example 46 was maintained in a
F.sub.2 gas atmosphere (temperature 25.degree. C.) at pressure of
38 Torr for 1 minute to form a fluoride layer on the surface of the
MgO powder. The MgO powder was used for forming a film body on a
glass substrate by the same method as Example 46. The MgO powder
having the surface coated with the fluoride layer, and the glass
substrate were referred to as "Example 48".
EXAMPLE 49
[0184] The same MgO powder as Example 46 was maintained in a
F.sub.2 gas atmosphere (temperature 25.degree. C.) at pressure of
38 Torr for 10 minutes to form a fluoride layer on the surface of
the MgO powder. The MgO powder was used for forming a film body on
a glass substrate by the same method as Example 46. The MgO powder
having the surface coated with the fluoride layer, and the glass
substrate were referred to as "Example 49".
EXAMPLE 50
[0185] The same MgO powder as Example 46 was maintained in a
F.sub.2 gas atmosphere (temperature 25.degree. C.) at pressure of
38 Torr for 60 minutes to form a fluoride layer on the surface of
the MgO powder. The MgO powder was used for forming a film body on
a glass substrate by the same method as Example 46. The MgO powder
having the surface coated with the fluoride layer, and the glass
substrate were referred to as "Example 50".
EXAMPLE 51
[0186] The same MgO powder as Example 46 was maintained in a
F.sub.2 gas atmosphere (temperature 25.degree. C.) at pressure of
7.6 Torr for 10 minutes to form a fluoride layer on the surface of
the MgO powder. The MgO powder was used for forming a film body on
a glass substrate by the same method as Example 46. The MgO powder
having the surface coated with the fluoride layer, and the glass
substrate were referred to as "Example 51".
EXAMPLE 52
[0187] The same MgO powder as Example 46 was maintained in an
atmosphere (temperature 25.degree. C.) of a gas mixture containing
F.sub.2 gas at partial pressure of 7.6 Torr and N.sub.2 gas at
partial pressure of 752 Torr for 10 minutes to form a fluoride
layer on the surface of the MgO powder. The MgO powder was used for
forming a film body on a glass substrate by the same method as
Example 46. The MgO powder having the surface coated with the
fluoride layer, and the glass substrate were referred to as
"Example 52".
EXAMPLE 53
[0188] The same MgO powder as Example 46 was maintained in a
F.sub.2 gas atmosphere (temperature 100.degree. C.) at pressure of
7.6 Torr for 10 minutes to form a fluoride layer on the surface of
the MgO powder. The MgO powder was used for forming a film body on
a glass substrate by the same method as Example 46. The MgO powder
having the surface coated with the fluoride layer, and the glass
substrate were referred to as "Example 53".
EXAMPLE 54
[0189] The same MgO powder as Example 46 was maintained in a HF gas
atmosphere (temperature 25.degree. C.) at pressure of 38 Torr for 1
minute to form a fluoride layer on the surface of the MgO powder.
The MgO powder was used for forming a film body on a glass
substrate by the same method as Example 46. The MgO powder having
the surface coated with the fluoride layer, and the glass substrate
were referred to as "Example 54".
EXAMPLE 55
[0190] The same MgO powder as Example 46 was maintained in an
atmosphere (temperature 25.degree. C.) of a gas mixture containing
HF gas at partial pressure of 7.6 Torr and N.sub.2 gas at partial
pressure of 752 Torr for 10 minutes to form a fluoride layer on the
surface of the MgO powder. The MgO powder was used for forming a
film body on a glass substrate by the same method as Example 46.
The MgO powder having the surface coated with the fluoride layer,
and the glass substrate were referred to as "Example 55".
EXAMPLE 56
[0191] The same MgO powder as Example 46 was maintained in a
BF.sub.3 gas atmosphere (temperature 25.degree. C.) at pressure of
7.6 Torr for 10 minutes to form a fluoride layer on the surface of
the MgO powder. The MgO powder was used for forming a film body on
a glass substrate by the same method as Example 46. The MgO powder
having the surface coated with the fluoride layer, and the glass
substrate were referred to as "Example 56".
EXAMPLE 57
[0192] The same MgO powder as Example 46 was maintained in a
SbF.sub.5 gas atmosphere (temperature 25.degree. C.) at pressure of
7.6 Torr for 10 minutes to form a fluoride layer on the surface of
the MgO powder. The MgO powder was used for forming a film body on
a glass substrate by the same method as Example 46. The MgO powder
having the surface coated with the fluoride layer, and the glass
substrate were referred to as "Example 57".
EXAMPLE 58
[0193] The same MgO powder as Example 46 was maintained in a
SF.sub.4 gas atmosphere (temperature 25.degree. C.) at pressure of
7.6 Torr for 10 minutes to form a fluoride layer on the surface of
the MgO powder. The MgO powder was used for forming a film body on
a glass substrate by the same method as Example 46. The MgO powder
having the surface coated with the fluoride layer, and the glass
substrate were referred to as "Example 58".
EXAMPLE 59
[0194] A fluoride layer was formed on the surface of a MgO powder
under the same conditions as Example 46. The MgO powder was
referred to as MgO powder of Example 59.
[0195] On the other hand, display electrodes and a transparent
dielectric layer were formed on the surface of a glass substrate
thereon by the same method as Example 46. Next, 5% by weight of MgO
powder with the surface coated with a fluoride layer, 1.25% by
weight of magnesium diethoxide as a binder, and 93.75% by weight of
ethyl cellosolve as a solvent were mixed to prepare a dispersion
for a film. The thus-prepared dispersion for a film was coated on
the glass substrate by spin coating to form a film body.
Furthermore, the glass substrate was dried by maintaining at
60.degree. C. in air for 30 minutes, and then burned by maintaining
at 580.degree. C. in air for 10 minutes. The thus-formed glass
substrate was referred to as "Example 59".
EXAMPLE 60
[0196] The same MgO powder as Example 59 was maintained in a
F.sub.2 gas atmosphere (temperature 25.degree. C.) at pressure of
72 Torr for 10 minutes to form a fluoride layer on the surface of
the MgO powder. The MgO powder was used for forming a film body on
a glass substrate by the same method as Example 59. The MgO powder
having the surface coated with the fluoride layer, and the glass
substrate were referred to as "Example 60".
EXAMPLE 61
[0197] The same MgO powder as Example 59 was maintained in a
F.sub.2 gas atmosphere (temperature 25.degree. C.) at pressure of
38 Torr for 1 minute to form a fluoride layer on the surface of the
MgO powder. The MgO powder was used for forming a film body on a
glass substrate by the same method as Example 59. The MgO powder
having the surface coated with the fluoride layer, and the glass
substrate were referred to as "Example 61".
EXAMPLE 62
[0198] The same MgO powder as Example 59 was maintained in a
F.sub.2 gas atmosphere (temperature 25.degree. C.) at pressure of
38 Torr for 10 minutes to form a fluoride layer on the surface of
the MgO powder. The MgO powder was used for forming a film body on
a glass substrate by the same method as Example 59. The MgO powder
having the surface coated with the fluoride layer, and the glass
substrate were referred to as "Example 62".
EXAMPLE 63
[0199] The same MgO powder as Example 59 was maintained in a
F.sub.2 gas atmosphere (temperature 25.degree. C.) at pressure of
38 Torr for 60 minutes to form a fluoride layer on the surface of
the MgO powder. The MgO powder was used for forming a film body on
a glass substrate by the same method as Example 59. The MgO powder
having the surface coated with the fluoride layer, and the glass
substrate were referred to as "Example 63".
EXAMPLE 64
[0200] The same MgO powder as Example 59 was maintained in a
F.sub.2 gas atmosphere (temperature 25.degree. C.) at pressure of
7.6 Torr for 10 minutes to form a fluoride layer on the surface of
the MgO powder. The MgO powder was used for forming a film body on
a glass substrate by the same method as Example 59. The MgO powder
having the surface coated with the fluoride layer, and the glass
substrate were referred to as "Example 64".
EXAMPLE 65
[0201] The same MgO powder as Example 59 was maintained in an
atmosphere (temperature 25.degree. C.) of a gas mixture containing
F.sub.2 gas at partial pressure of 7.6 Torr and N.sub.2 gas at
partial pressure of 752 Torr for 10 minutes to form a fluoride
layer on the surface of the MgO powder. The MgO powder was used for
forming a film body on a glass substrate by the same method as
Example 59. The MgO powder having the surface coated with the
fluoride layer, and the glass substrate were referred to as
"Example 65".
EXAMPLE 66
[0202] The same MgO powder as Example 59 was maintained in a
F.sub.2 gas atmosphere (temperature 100.degree. C.) at pressure of
7.6 Torr for 10 minutes to form a fluoride layer on the surface of
the MgO powder. The MgO powder was used for forming a film body on
a glass substrate by the same method as Example 59. The MgO powder
having the surface coated with the fluoride layer, and the glass
substrate were referred to as "Example 66".
EXAMPLE 67
[0203] The same MgO powder as Example 59 was maintained in a HF gas
atmosphere (temperature 25.degree. C.) at pressure of 38 Torr for 1
minute to form a fluoride layer on the surface of the MgO powder.
The MgO powder was used for forming a film body on a glass
substrate by the same method as Example 59. The MgO powder having
the surface coated with the fluoride layer, and the glass substrate
were referred to as "Example 67".
EXAMPLE 68
[0204] The same MgO powder as Example 59 was maintained in an
atmosphere (temperature 25.degree. C.) of a gas mixture containing
HF gas at partial pressure of 7.6 Torr and N.sub.2 gas at partial
pressure of 752 Torr for 10 minutes to form a fluoride layer on the
surface of the MgO powder. The MgO powder was used for forming a
film body on a glass substrate by the same method as Example 59.
The MgO powder having the surface coated with the fluoride layer,
and the glass substrate were referred to as "Example 68".
EXAMPLE 69
[0205] A film body was formed on a glass substrate by the same
method as Example 59 except that magnesium trifluoroacetate was
used as a binder, and the burning temperature was 500.degree. C.
The MgO powder having the surface coated with the fluoride layer,
and the glass substrate were referred to as "Example 69".
EXAMPLE 70
[0206] A film body was formed on a glass substrate by the same
method as Example 69 except that magnesium trifluoroacetylacetonate
was used as a binder, and the burning temperature was 500.degree.
C. The MgO powder having the surface coated with the fluoride
layer, and the glass substrate were referred to as "Example
70".
EXAMPLE 71
[0207] A film body was formed on a glass substrate by the same
method as Example 69 except that magnesium
hexafluoroacetylacetonate was used as a binder, and the burning
temperature was 500.degree.0 C. The MgO powder having the surface
coated with the fluoride layer, and the glass substrate were
referred to as "Example 71".
COMPARATIVE EXAMPLE 1
[0208] A film body was formed on a glass substrate by electron beam
evaporation in the same manner as Example 1 except that the surface
of the film body was not modified. The thus-obtained glass
substrate was referred to as "Comparative Example 1".
COMPARATIVE EXAMPLE 2
[0209] A film body was formed on a glass substrate by sputtering in
the same manner as Example 14 except that the surface of the film
body was not modified. The thus-obtained glass substrate was
referred to as "Comparative Example 2".
COMPARATIVE EXAMPLE 3
[0210] A film body was formed on a glass substrate by screen
printing, dried and then burned in the same manner as Example 24
except that the surface of the film body was not modified. The
thus-obtained glass substrate was referred to as "Comparative
Example 3".
COMPARATIVE EXAMPLE 4
[0211] A film body was formed on a glass substrate by screen
printing, dried and then burned in the same manner as Example 34
except that the surface of the film body was not modified. The
thus-obtained glass substrate was referred to as "Comparative
Example 4".
COMPARATIVE EXAMPLE 5
[0212] A film body was formed on a glass substrate by spin coating,
dried and then burned in the same manner as Example 35 except that
the surface of the film body was not modified. The thus-obtained
glass substrate was referred to as "Comparative Example 5".
COMPARATIVE EXAMPLE 6
[0213] A film body was formed on a glass substrate by spin coating,
dried and then burned in the same manner as Example 45 except that
the surface of the film body was not modified. The thus-obtained
glass substrate was referred to as "Comparative Example 6".
COMPARATIVE EXAMPLE 7
[0214] A film body was formed on a glass substrate by screen
printing in the same manner as Example 46 except that a MgO powder
having an unmodified surface was used. The MgO powder and glass
substrate were referred to as "Comparative Example 7".
COMPARATIVE EXAMPLE 8
[0215] A film body was formed on a glass substrate by spin coating
in the same manner as Example 59 except that a MgO powder having an
unmodified surface was used. The MgO powder and glass substrate
were referred to as "Comparative Example 8".
COMPARISON TEST 1 AND EVALUATION
[0216] In each of Examples 1 to 45 and Comparative Examples 1 to 6,
the thickness of the fluoride layer formed on the surface of the
film body on the glass substrate was measured by elemental analysis
in the depth direction by X-ray photoelectron spectroscopy.
[0217] The environment resistance of each of the film bodies was
evaluated by difficulty in changing from MgO to carbonate
(MgCO.sub.3). Specifically, each film body was allowed to stand in
air at 40.degree. C. and humidity of 90% for 2 weeks, and then the
MgO film was subjected to elemental analysis in the depth direction
by X-ray photoelectron spectroscopy so that a carbonate layer was
evaluated by a depth where carbon derived from magnesium carbonate
(MgCO.sub.3) was observed. Namely, the smaller the depth, i.e., the
thinner the carbonate layer, the more the environment resistance of
a protecting film improves.
[0218] Furthermore, in each of Examples 1 to 45 and Comparative
Examples 1 to 6, the breakdown voltage of the film body was
measured by a method in which the glass substrate was set in a
chamber, the chamber was evacuated and then filled with a gas
mixture of He and 2% Xe gas at 400 Torr, and then a voltage of 10
kHZ was applied.
[0219] The results of measurement are shown in Table 1 to 4.
1 TABLE 1 Environment Modification condition of film body (MgO)
Thickness resistance surface of Thickness Break- Type and partial
pressure of gas fluoride of down Example Temperature Time Partial
Partial layer carbonate voltage No. (.degree. C.) (min) Gas
pressure Gas pressure (nm) (nm) Vf (V) 1 25 10 F.sub.2 152 -- -- 24
1 160 2 25 10 F.sub.2 72 -- -- 16 1 163 3 25 1 F.sub.2 38 -- -- 10
3 166 4 25 10 F.sub.2 38 -- -- 15 1 160 5 25 60 F.sub.2 38 -- -- 30
1 156 6 25 10 F.sub.2 7.6 -- -- 5 7 167 7 25 10 F.sub.2 7.6 N.sub.2
752 6 10 163 8 100 10 F.sub.2 7.6 -- -- 22 1 157 9 25 1 HF 38 -- --
5 12 169 10 25 10 HF 7.6 N.sub.2 752 2 15 166 11 25 10 BF.sub.3 7.6
-- -- 4 10 165 12 25 10 SbF.sub.5 7.6 -- -- 5 7 165 13 25 10
SF.sub.4 7.6 -- -- 2 11 168 Comp. -- -- -- -- -- -- Untreated 17
172 Example 1
[0220]
2 TABLE 2 Environment Modification condition of film body (MgO)
Thickness resistance surface of Thickness Break- Type and partial
pressure of gas fluoride of down Example Temperature Time Partial
Partial layer carbonate voltage No. (.degree. C.) (min) Gas
pressure Gas pressure (nm) (nm) Vf (V) 14 25 10 F.sub.2 152 -- --
10 1 155 15 25 10 F.sub.2 72 -- -- 9 1 158 16 25 1 F.sub.2 38 -- --
5 1 162 17 25 10 F.sub.2 38 -- -- 9 1 158 18 25 60 F.sub.2 38 -- --
17 1 157 19 25 10 F.sub.2 7.6 -- -- 4 3 162 20 25 10 F.sub.2 7.6
N.sub.2 752 4 6 163 21 100 10 F.sub.2 7.6 -- -- 10 1 156 22 25 1 HF
38 -- -- 2 7 160 23 25 10 HF 7.6 N.sub.2 752 1 7 160 Comp. -- -- --
-- -- -- Untreated 10 165 Example 2
[0221]
3 TABLE 3 Environment Modification condition of film body (MgO)
Thickness resistance surface of Thickness Break- Type and partial
pressure of gas fluoride of down Example Temperature Time Partial
Partial layer carbonate voltage No. (.degree. C.) (min) Gas
pressure Gas pressure (nm) (nm) Vf (V) 24 25 10 F.sub.2 152 -- --
36 2 182 25 25 10 F.sub.2 72 -- -- 24 2 184 26 25 1 F.sub.2 38 --
-- 12 5 189 27 25 10 F.sub.2 38 -- -- 20 3 185 28 25 60 F.sub.2 38
-- -- 44 1 179 29 25 10 F.sub.2 7.6 -- -- 8 10 190 30 25 10 F.sub.2
7.6 N.sub.2 752 8 12 184 31 100 10 F.sub.2 7.6 -- -- 30 1 180 32 25
1 HF 38 -- -- 6 15 190 33 25 10 HF 7.6 N.sub.2 752 4 20 189 34 25
10 F.sub.2 152 -- -- 420 5 188 Comp. -- -- -- -- -- -- Untreated 22
196 Example 3 Comp. -- -- -- -- -- -- Untreated 510 201 Example
4
[0222]
4 TABLE 4 Environment Modification condition of film body (MgO)
Thickness resistance surface of Thickness Break- Type and partial
pressure of gas fluoride of down Example Temperature Time Partial
Partial layer carbonate voltage No. (.degree. C.) (min) Gas
pressure Gas pressure (nm) (nm) Vf (V) 35 25 10 F.sub.2 152 -- --
42 2 180 36 25 10 F.sub.2 72 -- -- 20 4 185 37 25 1 F.sub.2 38 --
-- 8 7 190 38 25 10 F.sub.2 38 -- -- 26 4 185 39 25 60 F.sub.2 38
-- -- 35 2 183 40 25 10 F.sub.2 7.6 -- -- 12 8 190 41 25 10 F.sub.2
7.6 N.sub.2 752 14 10 184 42 100 10 F.sub.2 7.6 -- -- 30 3 183 43
25 1 HF 38 -- -- 6 18 190 44 25 10 HF 7.6 N.sub.2 752 6 18 191 45
25 10 F.sub.2 152 -- -- 510 7 189 Comp. -- -- -- -- -- -- Untreated
30 195 Example 5 Comp. -- -- -- -- -- -- Untreated 560 200 Example
6
[0223] Tables 1 to 4 indicate that in Comparative Examples 1 to a 3
and 5, the thicknesses of the carbonate layers (MgCO.sub.3) formed
on the film bodies are as large as 17 nm, 10 nm, 22 m, and 30 nm,
respectively, and in Comparative Examples 4 and 6 containing a MgO
powder, carbonate (MgCO.sub.3) is formed substantially over the
entire film body. On the other hand, in each of Examples 1 to 45,
the thickness of the carbonate layer is 1 to 20 nm which is smaller
than the corresponding comparative example. It is also found that
as the thickness of the fluoride layer formed on the surface of the
film body increases, the thickness of the carbonate layer
decreases.
[0224] In Comparative Examples 1 and 2, the breakdown voltages are
172 and 165 V, respectively, while in Examples 1 to 23
corresponding to Comparative Examples 1 and 2, the breakdown
voltages are a slightly lower value of 155 to 169 V. In Comparative
Examples 3 to 6, the breakdown voltage are 195 to 201 V, while in
Examples 24 to 45 corresponding to Comparative Examples 3 to 6, the
breakdown voltages are a lower value of 179 to 191 V. It is thus
found that in Examples of the present invention, the secondary
electron emitting ability is high, and thus the performance of PDP
is improved.
COMPARISON TEST 2 AND EVALUATION
[0225] In Examples 46 to 71 and Comparative Examples 7 and 8, it
was difficult to measure the thickness of the fluoride layers
formed on the surfaces of the MgO powder because the MgO powder was
fine. Therefore, as a reference, the thickness of a fluoride layer
formed on the surface a MgO sputtered film under the same
conditions as Examples and Comparative Examples was measured by
elemental analysis in the depth direction by X-ray photoelectron
spectroscopy.
[0226] The environment resistance of MgO powder was evaluated by
difficulty in changing from MgO to carbonate (MgCO.sub.3) in the
same manner as Comparison Test 1. Specifically, the MgO powder was
allowed to stand in air at 40.degree. C. and humidity of 90% for 2
weeks, the carbonate layer on the surface of the MgO powder was
evaluated by a relative value (a. u.: arbitrary unit) of absorbance
at a peak near 1450 cm.sup.-1 derived from the carbonate in diffuse
reflectance infrared spectroscopy (FT-IR). The smaller the relative
value of the absorbance, i.e., the thinner the carbonate layer, the
more the environment resistance of the MgO powder improves.
Furthermore, the breakdown voltage (Vf) of the MgO film was
measured by the same method as Comparison Test 1. The results of
measurement are shown in Tables 5 and 6.
5 TABLE 5 Modification condition of power (MgO) Thickness surface
of Environment Break- Type and partial pressure of gas fluoride
resistance down Example Temperature Time Partial Partial layer
Carbonate voltage No. (.degree. C.) (min) Gas pressure Gas pressure
(nm) (a. u.) Vf (V) 46 25 10 F.sub.2 152 -- -- 10 10 179 47 25 10
F.sub.2 72 -- -- 9 9 180 48 25 1 F.sub.2 38 -- -- 5 25 187 49 25 10
F.sub.2 38 -- -- 9 10 185 50 25 60 F.sub.2 38 -- -- 17 7 180 51 25
10 F.sub.2 7.6 -- -- 4 48 186 52 25 10 F.sub.2 7.6 N.sub.2 752 4 48
181 53 100 10 F.sub.2 7.6 -- -- 10 3 181 54 25 1 HF 38 -- -- 2 65
187 55 25 10 HF 7.6 N.sub.2 752 1 58 186 56 25 10 BF.sub.3 7.6 --
-- 3 49 186 57 25 10 SbF.sub.5 7.6 -- -- 3 47 185 58 25 10 SF.sub.4
7.6 -- -- 1 53 187 Comp. -- -- -- -- -- -- Untreated 78 195 Example
7
[0227]
6 TABLE 6 Modification condition of power (MgO) Thickness surface
of Environment Break- Type and partial pressure of gas fluoride
resistance down Example Temperature Time Partial Partial layer
Carbonate voltage No. (.degree. C.) (min) Gas pressure Gas pressure
(nm) (a. u.) Vf (V) 59 25 10 F.sub.2 152 -- -- 10 10 177 60 25 10
F.sub.2 72 -- -- 9 9 179 61 25 1 F.sub.2 38 -- -- 5 25 185 62 25 10
F.sub.2 38 -- -- 9 10 180 63 25 60 F.sub.2 38 -- -- 17 7 177 64 25
10 F.sub.2 7.6 -- -- 4 48 188 65 25 10 F.sub.2 7.6 N.sub.2 752 4 48
180 66 100 10 F.sub.2 7.6 -- -- 10 3 179 67 25 1 HF 38 -- -- 2 65
185 68 25 10 HF 7.6 N.sub.2 752 1 58 183 69 25 10 F.sub.2 152 -- --
10 10 170 70 25 10 F.sub.2 152 -- -- 10 10 172 71 25 10 F.sub.2 152
-- -- 10 10 171 Comp. -- -- -- -- -- -- Untreated 78 196 Example
8
[0228] Tables 5 and 6 indicate that in Comparative Examples 7 and
8, the amounts of carbonate (MgCO.sub.3) formed on the MgO powder
surfaces are as large as 78, while in Examples 46 to 71, the
amounts of carbonate are as small as 3 to 65. It is also found that
the thicker the fluoride layer formed on the MgO powder (MgO
sputtered film) surface, the smaller the amount of carbonate.
[0229] In Comparative Examples 7 and 8, the breakdown voltages are
195 and 196 V, respectively, while in Examples 46 to 71, the
breakdown voltages are as low as 170 to 188 V. It is thus found
that in Examples of the present invention, the secondary electron
emitting ability is high, and thus the performance of PDP is
improved.
EXAMPLES 101 TO 128
[0230] A film body was formed on a glass substrate, and a fluoride
layer was formed on the surface of the film body by the same method
as each of Examples 1 to 14, 16, 18, 21, 23, 24, 26, 28, 31, 33,
34, 37, 39, 42 and 44 except that a CaO power was used in place of
the MgO powder. The thus-obtained glass substrates are respectively
referred to as "Examples 101 to 128".
EXAMPLES 129 TO 153
[0231] A CaO powder was coated with a fluoride layer, and then used
for forming a film body on the surface of a glass substrate by the
same method as each of examples 46 to 63 and 65 to 71 except that a
CaO powder (average particle size: 500 .ANG.) produced by
precipitation in water was used in place of the MgO powder (average
particle size: 100 .ANG.) produced by a vapor phase method. The
thus-obtained CaO powder coated with the fluoride layer and glass
substrates are respectively referred to as "Examples 129 to
153".
COMPARATIVE EXAMPLES 101 TO 104
[0232] A film body was formed on a glass substrate without
modification of the surface of the film body by the same method as
each of Comparative Examples 1 to 3 and 5 except that a CaO power
was used in place of the MgO powder. The thus-obtained glass
substrates are respectively referred to as "Comparative Examples
101 to 104".
COMPARATIVE EXAMPLES 105 AND 106
[0233] A CaO powder having the unmodified surface was used for
forming a film body on the surface of a glass substrate by the same
method as each of Comparative examples 7 and 8 except that a CaO
powder (average particle size: 500 .ANG.) produced by an underwater
synthetic method was used in place of the MgO powder (average
particle size: 100 .ANG.) produced by a vapor phase method. The
thus-obtained CaO powder and glass substrates are respectively
referred to as "Examples 105 and 106".
COMPARISON TEST 3 AND EVALUATION
[0234] In each of Examples 101 to 128 and Comparative Examples 101
to 104, the thickness of the fluoride layer formed on the surface
of the film body on the glass substrate was measured by elemental
analysis in the depth direction by X-ray photoelectron
spectroscopy.
[0235] The environment resistance of each of the film bodies was
evaluated by difficulty in changing from CaO to carbonate
(CaCO.sub.3). Specifically, each film body was allowed to stand in
air (CO.sub.2 concentration: about 300 ppm) at 40.degree. C. and
humidity of 90% for 2 weeks, and then subjected to elemental
analysis in the depth direction by X-ray photoelectron spectroscopy
so that a carbonate layer was evaluated by a depth where carbon
derived from calcium carbonate (CaCO.sub.3) was observed. Namely,
the smaller the depth, i.e., the thinner the carbonate layer, the
more the environment resistance of a protecting film improves.
[0236] Furthermore, in each of Examples 101 to 128 and Comparative
Examples 101 to 104, the breakdown voltage of the film body was
measured by a method in which the glass substrate was set in a
chamber, the chamber was evacuated and then filled with a gas
mixture of He and 2% Xe gas at 400 Torr, and then a voltage of 10
kHZ was applied.
[0237] The results of measurement are shown in Table 7 and 8.
7 TABLE 7 Environment Modification condition of film body (CaO)
Thickness resistance surface of Thickness Break- Type and partial
pressure of gas fluoride of down Example Temperature Time Partial
Partial layer carbonate voltage No. (.degree. C.) (min) Gas
pressure Gas pressure (nm) (nm) Vf (V) 101 25 10 F.sub.2 152 -- --
30 1 165 102 25 10 F.sub.2 72 -- -- 18 1 162 103 25 1 F.sub.2 38 --
-- 15 1 160 104 25 10 F.sub.2 38 -- -- 12 2 162 105 25 60 F.sub.2
38 -- -- 26 1 158 106 25 10 F.sub.2 7.6 -- -- 5 10 172 107 25 10
F.sub.2 7.6 N.sub.2 752 10 7 170 108 100 10 F.sub.2 7.6 -- -- 25 2
163 109 25 1 HF 38 -- -- 10 8 174 110 25 10 HF 7.6 N.sub.2 752 3 10
172 111 25 10 BF.sub.3 7.6 -- -- 4 12 170 112 25 10 SbF.sub.5 7.6
-- -- 8 5 166 113 25 10 SF.sub.4 7.6 -- -- 8 6 167 Comp. -- -- --
-- -- -- Untreated 20 180 Example 101
[0238]
8 TABLE 8 Environment Modification condition of film body (CaO)
Thickness resistance surface of Thickness Break- Type and partial
pressure of gas fluoride of down Example Temperature Time Partial
Partial layer carbonate voltage No. (.degree. C.) (min) Gas
pressure Gas pressure (nm) (nm) Vf (V) 114 25 10 F.sub.2 152 -- --
15 1 160 115 25 1 F.sub.2 38 -- -- 6 3 162 116 25 60 F.sub.2 38 --
-- 17 1 158 117 100 10 F.sub.2 7.6 -- -- 13 1 160 118 25 10 HF 7.6
N.sub.2 752 4 3 163 119 25 10 F.sub.2 152 -- -- 43 2 185 120 25 1
F.sub.2 38 -- -- 19 5 191 121 25 60 F.sub.2 38 -- -- 37 3 180 122
100 10 F.sub.2 7.6 -- -- 33 4 188 123 25 10 HF 7.6 N.sub.2 752 10 8
194 124 25 10 F.sub.2 152 -- -- 37 3 180 125 25 1 F.sub.2 38 -- --
20 3 182 126 25 60 F.sub.2 38 -- -- 40 2 176 127 100 10 F.sub.2 7.6
35 2 179 128 25 10 HF 7.6 N.sub.2 752 8 10 191 Comp. -- -- -- -- --
-- Untreated 20 200 Example 102 Comp. -- -- -- -- -- -- Untreated
25 205 Example 103 Comp. -- -- -- -- -- -- Untreated 23 206 Example
104
[0239] Tables 7 and 8 indicate that in each of Comparative Examples
101 to 104, the thickness of the carbonate layer (CaCO.sub.3)
formed on the film body is as large as 20 to 25 nm, while in each
of Examples 101 to 128, the thickness of the carbonate layer is as
small as 1 to 12 nm. It is also found that as the thickness of the
fluoride layer formed on the surface of the film body increases,
the thickness of the carbonate layer decreases.
[0240] In Comparative Example 101, the breakdown voltage is 180 V,
while in Examples 101 to 113 corresponding to Comparative Example
101, the breakdown voltages are a slightly lower value of 158 to
174 V. In Comparative Examples 102 to 104, the breakdown voltages
are 200 to 206 V, while in Examples 114 to 128 corresponding to
Comparative Examples 102 to 104, the breakdown voltages are a lower
value of 158 to 194 V. It is thus found that in Examples of the
present invention, the secondary electron emitting ability is high,
and thus the performance of PDP is improved.
COMPARISON TEST 4 AND EVALUATION
[0241] In Examples 129 to 153 and Comparative Examples 105 and 106,
it was difficult to measure the thickness of the fluoride layers
formed on the surfaces of the CaO powder because the CaO powder was
fine. Therefore, as a reference, the thickness of a fluoride layer
formed on the surface a CaO sputtered film under the same
conditions as each of Examples and Comparative Examples was
measured by elemental analysis in the depth direction by X-ray
photoelectron spectroscopy.
[0242] The environment resistance of the CaO powder was evaluated
by difficulty in changing from CaO to carbonate (CaCO.sub.3) in the
same manner as Comparison Test 3. Specifically, the CaO powder was
allowed to stand in air (CO.sub.2 concentration: about 300 ppm) at
40.degree. C. and humidity or 90% for 2 weeks, the carbonate layers
on the surfaces of the CaO powder were evaluated by a relative
value (a. u.: arbitrary unit) of absorbance at a peak near 1450
cm.sup.-1 derived from the carbonate in diffuse reflectance
infrared spectroscopy (FT-IR). The smaller the relative value of
the absorbance, i.e., the thinner the carbonate layer, the more the
environment resistance of the CaO powder improves. Furthermore, the
breakdown voltage (Vf) of each film body was measured by the same
method as Comparison Test 3. The results of measurement are shown
in Tables 9 and 10.
9 TABLE 9 Modification condition of powder (CaO) Thickness surface
of Environment Break- Type and partial pressure of gas fluoride
resistance down Example Temperature Time Partial Partial layer
Carbonate voltage No. (.degree. C.) (min) Gas pressure Gas pressure
(nm) (a. u.) Vf (V) 129 25 10 F.sub.2 152 -- -- 15 9 183 129 25 10
F.sub.2 152 -- -- 15 9 183 130 25 10 F.sub.2 72 -- -- 11 21 181 131
25 1 F.sub.2 38 -- -- 6 20 190 132 25 10 F.sub.2 38 -- -- 15 12 183
133 25 60 F.sub.2 38 -- -- 17 8 180 134 25 10 F.sub.2 7.6 -- -- 10
25 185 135 25 10 F.sub.2 7.6 N.sub.2 752 9 24 196 136 100 10
F.sub.2 7.6 -- -- 13 15 195 137 25 1 HF 38 -- -- 4 40 195 138 25 10
HF 7.6 N.sub.2 752 4 52 196 139 25 10 BF.sub.3 7.6 -- -- 8 33 188
140 25 10 SbF.sub.5 7.6 -- -- 6 40 190 141 25 10 SF.sub.4 7.6 -- --
5 38 191 Comp. -- -- -- -- -- -- Untreated 92 206 Example 105
[0243]
10 TABLE 10 Modification condition of powder (CaO) Thickness
surface of Environment Break- Type and partial pressure of gas
fluoride resistance down Example Temperature Time Partial Partial
layer Carbonate voltage No. (.degree. C.) (min) Gas pressure Gas
pressure (nm) (a. u.) Vf (V) 142 25 10 F.sub.2 152 -- -- 15 9 180
143 25 10 F.sub.2 72 -- -- 11 21 185 144 25 1 F.sub.2 38 -- -- 6 20
186 145 25 10 F.sub.2 38 -- -- 15 12 180 146 25 60 F.sub.2 38 -- --
17 8 176 147 25 10 F.sub.2 7.6 N.sub.2 752 9 24 188 148 100 10
F.sub.2 7.6 -- -- 13 15 180 149 25 1 HF 38 -- -- 4 40 189 150 25 10
HF 7.6 N.sub.2 752 4 52 192 151 25 10 F.sub.2 152 -- -- 15 9 176
152 25 10 F.sub.2 152 -- -- 15 9 179 153 25 10 F.sub.2 152 -- -- 15
9 183 Comp. -- -- -- -- -- -- Untreated 92 199 Example 106
[0244] Tables 9 and 10 indicate that in Comparative Examples 105
and 106, the amounts of carbonate formed on the CaO powder surfaces
are as large as 92, while in Examples 129 to 153, the amounts of
carbonate are as small as 8 to 52. It is also found that the
thicker the fluoride layer formed on the CaO powder (CaO sputtered
film) surface, the smaller the amount of carbonate.
[0245] In Comparative Examples 105 and 106, the breakdown voltages
are 206 and 199 V, respectively, while in Examples 129 to 153, the
breakdown voltages are as low as 176 to 196 V. It is thus found
that in Examples of the present invention, the secondary electron
emitting ability is high, and thus the performance of PDP is
improved.
EXAMPLES 201 TO 227
[0246] First, display electrodes (thickness 5 .mu.m) composed of Ag
were formed on the surface of a glass substrate having a thickness
of 3 mm by screen printing, and then a transparent dielectric layer
(thickness 20 .mu.m) composed of glass was formed thereon by screen
printing, as shown in FIG. 1. Next, the glass substrate was dried
by maintaining in air at 150.degree. C. for 30 minutes, and then
burned in air at 550.degree. C. for 30 minutes.
[0247] A film body (deposited film) was formed on the surface of
the glass substrate by electron beam evaporation using each of the
various evaporated materials shown in Table 11 by the same
operation as Example 101. Then, the surface of the film body of the
glass substrate was modified under the conditions shown in Table 11
to form a fluoride layer on the surface of the film body. The
thus-obtained glass substrates are respectively referred to as
"Examples 201 to 227". In Examples 224 to 227, a film was deposited
by using an evaporated material comprising MgO and 2 mol % of each
of LaB.sub.6, La.sub.2O.sub.3, Sc.sub.2O.sub.3, and Y.sub.2O.sub.3,
and then modified with fluorine.
EXAMPLES 228 TO 250
[0248] 5 g of oxide powder (average particle size: about 500 .ANG.)
produced by precipitation in water was fluorinated under the
conditions shown in Table 12 to modify the surfaces of the oxide
powder. Namely, the surfaces of the oxide powder were coated with
fluoride layers. The thus-obtained oxide powders were respectively
referred to as "the oxide powders of Examples 228 to 250".
[0249] On the other hand, display electrodes (thickness of 5 .mu.m)
made of Ag were formed on a front glass substrate having a
thickness of 3 mm by screen printing, and then a transparent
dielectric layer (thickness of 20 .mu.m) made of glass was formed
thereon by screen printing, as shown in FIG. 3. Next, 5% by weight
oxide powder having the surface coated with the fluoride layer,
1.25% by weight of organic acid compound (which decomposes to each
of the oxides shown in Table 12 after burning) as a binder, and
93.75% by weight of ethyl cellosolve as a solvent were mixed to
prepare a dispersion for a film. The thus-prepared dispersion was
coated on the glass substrate by spin coating to form a film body
(spin-coated film). Furthermore, the glass substrate was dried by
maintaining at 60.degree. C. in air for 30 minutes, and then burned
by maintaining at 580.degree. C. in air for 10 minutes. The
thus-formed glass substrates were respectively referred to as "the
glass substrates of Examples 228 to 250".
COMPARATIVE EXAMPLES 201 TO 227
[0250] A film body (deposited film) was formed on a glass substrate
by electron beam evaporation in the same manner as each of Examples
201 to 227 except that the surface of the film body was not
modified. The thus-obtained glass substrates were respectively
referred to as "Comparative Examples 201 to 227".
COMPARATIVE EXAMPLES 228 TO 250
[0251] A film body (oxide film) was formed on a glass substrate by
spin coating in the same manner as each of Examples 228 to 250
except that an oxide powder having the unmodified surface was used.
The thus-obtained oxide compound powders and glass substrates were
respectively referred to as "Comparative Examples 228 to 250".
COMPARISON TEST 5 AND EVALUATION
[0252] In each of Examples 201 to 227 and Comparative Examples 201
to 227, the thickness of the fluoride layer formed on the surface
of the film body on the glass substrate was measured by elemental
analysis in the depth direction by X-ray photoelectron
spectroscopy.
[0253] The environment resistance of each of the film bodies was
evaluated by difficulty in changing to carbonate. Specifically, a
film body was allowed to stand in air (CO.sub.2 concentration:
about 300 ppm) at 40.degree. C. and humidity of 90% for 2 weeks,
and then subjected to elemental analysis in the depth direction by
X-ray photoelectron spectroscopy so that a carbonate layer was
evaluated by a depth where carbon derived from the carbonate was
observed. Namely, the smaller the depth, i.e., the thinner the
carbonate layer, the more the environment resistance of a
protecting film improves.
[0254] Furthermore, in each of Examples 201 to 227 and Comparative
Examples 201 to 227, the breakdown voltage of the film body was
measured by a method in which the glass substrate was set in a
chamber, the chamber was evacuated and then filled with a gas
mixture of He and 2% Xe gas at 400 Torr, and then a voltage of 10
kHZ was applied. The results of measurement are shown in Table 11
and 12.
11 TABLE 11 Environment Modification condition of film Thickness
resistance body surface of Thickness Type Partial fluoride of
Breakdown Example Evaporated Temperature Time of pressure layer
carbonate voltage No. material (.degree. C.) (min) gas of gas (nm)
(nm) Vf (V) 201 SrO 25 1 HF 38 16 1 160 202 BaO " " " " 15 1 165
203 (Ca.Sr)O " " " " 12 2 155 204 (Mg.Sr)O " " " " 10 2 156 205
(Sr.Ba)O " " " " 16 1 160 206 Y.sub.2O.sub.3 " " " " 8 2 192 207
Gd.sub.2O.sub.3 " " " " 6 1 188 208 Dy.sub.2O.sub.3 " " " " 5 2 182
209 CeO.sub.2 " " " " 10 2 190 210 La.sub.2O.sub.3 " " " " 7 4 176
211 Yb.sub.2O.sub.3 " " " " 7 3 178 212 MgGd.sub.2O.sub.4 " " " " 7
3 182 213 MgY.sub.2O.sub.4 " " " " 8 3 176 214 MgLa.sub.2O.sub.4 "
" " " 6 2 172 215 CaGd.sub.2O.sub.4 " " " " 5 1 185 216
CaY.sub.2O.sub.4 " " " " 7 1 181 217 CaLa.sub.2O.sub.4 " " " " 9 2
180 218 SrGd.sub.2O.sub.4 " " " " 10 4 171 219 SrY.sub.2O.sub.4 " "
" " 10 4 168 220 SrLa.sub.2O.sub.4 " " " " 12 3 174 221
BaGd.sub.2O.sub.4 " " " " 15 3 177 222 BaY.sub.2O.sub.4 " " " " 18
1 182 223 BaLa.sub.2O.sub.4 " " " " 16 1 180 224 MaO:LaB.sub.6 " "
" " 10 2 162 225 MgO:La.sub.2O.sub.3 " " " " 8 4 158 226
MgO:Sc.sub.2O.sub.3 " " " " 12 5 157 227 MgO:Y.sub.2O.sub.3 " " " "
12 2 158
[0255]
12TABLE 12 Environment Modification condition of film Thickness
resistance Compara- body surface of Thickness tive Type Partial
fluoride of Breakdown Example Evaporated Temperature Time of
pressure layer carbonate voltage No. material (.degree. C.) (min)
gas of gas (nm) (nm) Vf (V) 201 SrO -- -- -- -- -- 22 185 202 BaO
-- -- -- -- -- 28 186 203 (Ca.Sr)O -- -- -- -- -- 25 179 204
(Mg.Sr)O -- -- -- -- -- 22 176 205 (Sr.Ba)O -- -- -- -- -- 25 191
206 Y.sub.2O.sub.3 -- -- -- -- -- 18 213 207 Gd.sub.2O.sub.3 -- --
-- -- -- 20 206 208 Dy.sub.2O.sub.3 -- -- -- -- -- 25 200 209
CeO.sub.2 -- -- -- -- -- 16 198 210 La.sub.2O.sub.3 -- -- -- -- --
19 190 211 Yb.sub.2O.sub.3 -- -- -- -- -- 26 208 212
MgGd.sub.2O.sub.4 -- -- -- -- -- 16 212 213 MgY.sub.2O.sub.4 -- --
-- -- -- 18 190 214 MgLa.sub.2O.sub.4 -- -- -- -- -- 26 185 215
CaGd.sub.2O.sub.4 -- -- -- -- -- 14 187 216 CaY.sub.2O.sub.4 -- --
-- -- -- 16 189 217 CaLa.sub.2O.sub.4 -- -- -- -- -- 20 192 218
SrGd.sub.2O.sub.4 -- -- -- -- -- 22 192 219 SrY.sub.2O.sub.4 -- --
-- -- -- 27 185 220 SrLa.sub.2O.sub.4 -- -- -- -- -- 18 195 221
BaGd.sub.2O.sub.4 -- -- -- -- -- 16 202 222 BaY.sub.2O.sub.4 -- --
-- -- -- 14 201 223 BaLa.sub.2O.sub.4 -- -- -- -- -- 24 206 224
MaO:LaB.sub.6 -- -- -- -- -- 18 188 225 MgO:La.sub.2O.sub.3 -- --
-- -- -- 14 180 226 MgO:Sc.sub.2O.sub.3 -- -- -- -- -- 16 182 227
MgO:Y.sub.2O.sub.3 -- -- -- -- -- 16 186
[0256] Tables 11 and 12 indicate that in each of Comparative
Examples 201 to 227, the thickness of the carbonate layer formed on
the film body is as large as 14 to 28 nm, while in each of Examples
201 to 227, the thickness of the carbonate layer is as small as 1
to 5 nm. In Examples 201 to 227, as the thickness of the fluoride
layer formed on the surface of the film body increases, the
thickness of the carbonate layer decreases.
[0257] In Comparative Examples 201 to 227, the breakdown. voltages
are 176 to 213 V, respectively, while in Examples 201 to 227
corresponding to Comparative Examples 201 to 227, the breakdown
voltages are slightly lower values of 155 to 192 V. It is thus
found that in Examples of the present invention, the secondary
electron emitting ability is high, and thus the performance of PDP
is improved.
COMPARISON TEST 6 AND EVALUATION
[0258] In Examples 228 to 250 and Comparative Examples 228 to 250,
it was difficult to measure the thickness of the fluoride layers
formed on the surfaces of the oxide powder because the oxide powder
was fine. Therefore, as a reference, the thickness of a fluoride
layer formed on the surface a sputtered film under the same
conditions as each of Examples and Comparative Examples was
measured by elemental analysis in the depth direction by X-ray
photoelectron spectroscopy.
[0259] The environment resistance of oxide powder was evaluated by
difficulty in changing to the carbonate in the same manner as
Comparison Test 5. Specifically, the oxide powder was allowed to
stand in air (CO.sub.2 concentration: about 300 ppm) at 40.degree.
C. and humidity or 90% for 2 weeks, the carbonate layer on the
surface of the oxide powder was evaluated by a relative value (a.
u.: arbitrary unit) of absorbance at a peak near 1450 cm.sup.-1
derived from the carbonate in diffuse reflectance infrared
spectroscopy (FT-IR). The smaller the relative value of the
absorbance, i.e., the thinner the carbonate layer, the more the
environment resistance of the oxide powder improves. Furthermore,
the breakdown voltage (Vf) of each film body was measured by the
same method as Comparison Test 5. The results of measurement are
shown in Tables 13 and 14.
13 TABLE 13 Modification condition of oxide Thickness Dispersion
for powder surface of Environment film Type Partial fluoride
resistance Breakdown Example Oxide Temperature Time of pressure
layer Carbonate voltage No. powder Binder (.degree. C.) (min) gas
of gas (nm) (a.u.) Vf (V) 228 SrO SrO 25 10 HF/N.sub.2 8/752 6 18
183 229 BaO BaO " " " " 7 16 198 230 (Ca.Sr)0 (Ca.Sr)0 " " " " 8 25
180 231 (Mg.Sr)0 (Mg.Sr)0 " " " " 5 17 185 232 (Sr.Ba)0 (Sr.Ba)0 "
" " " 6 18 184 233 Y.sub.2O.sub.3 Y.sub.2O.sub.3 " " " " 4 16 216
234 Gd.sub.2O.sub.3 Gd.sub.2O.sub.3 " " " " 5 20 201 235
Dy.sub.2O.sub.3 Dy.sub.2O.sub.3 " " " " 6 20 206 236
Dy.sub.2O.sub.3 Dy.sub.2O.sub.3 " " " " 8 31 210 237 CeO.sub.2
CeO.sub.2 " " " " 7 32 221 238 La.sub.2O.sub.3 La.sub.2O.sub.3 " "
" " 5 25 209 239 MgGd.sub.2O.sub.4 MgGd.sub.2O.sub.4 " " " " 4 20
209 240 MgY.sub.2O.sub.4 MgY.sub.2O.sub.4 " " " " 3 18 196 241
MgLa.sub.2O.sub.4 MgLa.sub.2O.sub.4 " " " " 4 25 198 242
CaGd.sub.2O.sub.4 CaGd.sub.2O.sub.4 " " " " 5 22 195 243
CaY.sub.2O.sub.4 CaY.sub.2O.sub.4 " " " " 6 16 193 244
CaLa.sub.2O.sub.4 CaLa.sub.2O.sub.4 " " " " 8 14 190 245
SrGd.sub.2O.sub.4 SrGd.sub.2O.sub.4 " " " " 8 26 186 246
SrY.sub.2O.sub.4 SrY.sub.2O.sub.4 " " " " 9 20 189 247
SrLa.sub.2O.sub.4 SrLa.sub.2O.sub.4 " " " " 10 21 194 248
BaGd.sub.2O.sub.4 BaGd.sub.2O.sub.4 " " " " 11 23 197 249
BaY.sub.2O.sub.4 BaY.sub.2O.sub.4 " " " " 7 27 203 250
BaLa.sub.2O.sub.4 BaLa.sub.2O.sub.4 " " " " 11 19 200
[0260]
14 TABLE 14 Modification condition of oxide Thickness Dispersion
for powder surface of Environment Comp. film Type Partial fluoride
resistance Breakdown Example Oxide Temperature Time of pressure
layer Carbonate voltage No. powder Binder (.degree. C.) (min) gas
of gas (nm) (a.u.) Vf (V) 228 SrO SrO -- -- -- -- -- 101 201 229
BaO BaO -- -- -- -- -- 103 213 230 (Ca.Sr)0 (Ca.Sr)0 -- -- -- -- --
92 196 231 (Mg.Sr)0 (Mg.Sr)0 -- -- -- -- -- 90 190 232 (Sr.Ba)0
(Sr.Ba)0 -- -- -- -- -- 106 198 233 Y.sub.2O.sub.3 Y.sub.2O.sub.3
-- -- -- -- -- 100 232 234 Gd.sub.2O.sub.3 Gd.sub.2O.sub.3 -- -- --
-- -- 115 216 235 Dy.sub.2O.sub.3 Dy.sub.2O.sub.3 -- -- -- -- --
121 218 236 Dy.sub.2O.sub.3 Dy.sub.2O.sub.3 -- -- -- -- -- 130 230
237 CeO.sub.2 CeO.sub.2 -- -- -- -- -- 140 232 238 La.sub.2O.sub.3
La.sub.2O.sub.3 -- -- -- -- -- 121 240 239 MgGd.sub.2O.sub.4
MgGd.sub.2O.sub.4 -- -- -- -- -- 120 216 240 MgY.sub.2O.sub.4
MgY.sub.2O.sub.4 -- -- -- -- -- 109 200 241 MgLa.sub.2O.sub.4
MgLa.sub.2O.sub.4 -- -- -- -- -- 98 209 242 CaGd.sub.2O.sub.4
CaGd.sub.2O.sub.4 -- -- -- -- -- 95 212 243 CaY.sub.2O.sub.4
CaY.sub.2O.sub.4 -- -- -- -- -- 107 210 244 CaLa.sub.2O.sub.4
CaLa.sub.2O.sub.4 -- -- -- -- -- 112 199 245 SrGd.sub.2O.sub.4
SrGd.sub.2O.sub.4 -- -- -- -- -- 96 196 246 SrY.sub.2O.sub.4
SrY.sub.2O.sub.4 -- -- -- -- -- 89 196 247 SrLa.sub.2O.sub.4
SrLa.sub.2O.sub.4 -- -- -- -- -- 80 200 248 BaGd.sub.2O.sub.4
BaGd.sub.2O.sub.4 -- -- -- -- -- 92 212 249 BaY.sub.2O.sub.4
BaY.sub.2O.sub.4 -- -- -- -- -- 96 210 250 BaLa.sub.2O.sub.4
BaLa.sub.2O.sub.4 -- -- -- -- -- 108 211
[0261] Tables 13 and 14 indicate that in Comparative Examples
[0262] 228 to 250, the amounts of carbonate formed on the oxide
powder surfaces are as large as 80 to 140, while in Examples 228 to
250, the amounts of carbonate are as small as 14 to 32.
[0263] In Comparative Examples 228 to 250, the breakdown voltages
are 190 to 240 V, while in Examples 228 to 250 corresponding to
Comparative Examples 228 to 250, the breakdown voltages are as low
as 180 to 221 V. It is thus found that in Examples of the present
invention, the secondary electron emitting ability is high, and
thus the performance of PDP is improved.
EXAMPLE 301
[0264] First, as shown in FIG. 1, display electrodes (thickness of
5 .mu.m) made of Ag were formed on a front glass substrate having a
thickness of 3 mm by screen printing, and then a transparent
dielectric layer (thickness of 20 .mu.m) made of glass was formed
thereon by screen printing. Next, the glass substrate was dried by
maintaining in air at 150.degree. C. for 30 minutes, and then
burned by maintaining in air at 550.degree. C. for 30 minutes.
[0265] Then, using MgO sintered pellets having a purity of 99.8%,
MgO films were deposited in a vacuum by electron beam evaporation
to cover the surface of the transparent dielectric layer of the
glass substrate, to form the film body. The deposition conditions
for the film body included an acceleration voltage of 15 kV, a
deposition pressure of 1.times.10.sup.-2 Pa, and a deposition
distance of 600 nm. After the glass substrate was exposed to air,
the film body was burned in air at 350.degree. C. for 1 hour
together with the glass substrate to activate the film body. The
thus-obtained glass substrate was referred to as "Example 301".
EXAMPLE 302
[0266] A glass substrate was formed by the same method as Example
301 except that the burning temperature of the film body was
400.degree. C. The thus-obtained glass substrate was referred to as
"Example 302".
EXAMPLE 303
[0267] A glass substrate was formed by the same method as Example
301 except that the burning temperature of the film body was
450.degree. C. The thus-obtained glass substrate was referred to as
"Example 303".
EXAMPLE 304
[0268] A glass substrate was formed by the same method as Example
301 except that the burning temperature of the film body was
400.degree. C., and the burning time was 10 minutes. The
thus-obtained glass substrate was referred to as "Example 304".
EXAMPLE 305
[0269] A glass substrate was formed by the same method as Example
301 except that the burning temperature of the film body was
400.degree. C., and the burning time was 5 hours. The thus-obtained
glass substrate was referred to as "Example 305".
EXAMPLE 306
[0270] A glass substrate obtained by the same method as Example 304
was maintained in a HF gas atmosphere (temperature 25.degree. C.)
at pressure of 38 Torr for 10 minutes to modify the surface of the
film body, to form a fluoride layer on the surface of the film
body. The thus-obtained glass substrate was referred to as "Example
306".
EXAMPLE 307
[0271] A glass substrate was formed by the same method as Example
306 except that the glass substrate was not exposed to air after
evaporation, and not activated by heating. The thus-obtained glass
substrate was referred to as "Example 307".
COMPARATIVE EXAMPLE 301
[0272] A glass substrate was formed by the same method as Example
301 except that the film body was not burned (unburned). The
thus-obtained glass substrate was referred to as "Comparative
Example 301".
COMPARISON TEST 7 AND EVALUATION
[0273] The glass substrate of each of Examples 301 to 307 and
Comparative Example 301 was allowed to stand in air so that an
amount of contamination of the film body (mainly, contamination
with H.sub.2O and CO.sub.2 in air) was measured at predetermined
time intervals. The amount of contamination was determined by an
approximate total amount of the gases exhausted from room
temperature to 1000.degree. C., which was measured by monitoring
changes in pressure in a vacuum chamber in which each of the glass
substrates was heated from room temperature to 1000.degree. C. The
results are shown in FIGS. 6 to 8.
[0274] FIG. 6 reveals that in Comparative Example 301, the amount
of contamination is rapidly increased by allowing the glass
substrate to stand in air, while in Examples 301 to 303, the amount
of contamination increases a little. It is also found that the
amount of contamination in Example 303 having the higher burning
temperature less increases than in Example 301 having the lower
burning temperature.
[0275] FIG. 7 reveals that the amount of contamination in Example
306 having the longer burning time less increases than in Example
304 having the shorter burning time.
[0276] FIG. 8 reveals that fluorination significantly decreases the
amount of contamination, and fluorination without exposure to air
has the higher effect of decreasing contamination.
EXAMPLE 401
[0277] First, as shown in FIG. 5, display electrodes (thickness of
5 .mu.m) made of Ag were formed on a front glass substrate having a
thickness of 3 mm by screen printing, and then a transparent
dielectric layer (thickness of 20 .mu.m) made of glass was formed
thereon by screen printing. Next, the glass substrate was dried by
maintaining in air at 150.degree. C. for 30 minutes, and then
burned by maintaining in air at 550.degree. C. for 30 minutes.
[0278] Then, MgO sintered pellets having a purity of 99.8% were
deposited in a vacuum by electron beam evaporation to cover the
surface of the transparent dielectric layer 17 of the glass
substrate, to form a protecting film composed of MgO. The
deposition conditions for the protecting film body included an
acceleration voltage of 15 kV, a deposition pressure of
1.times.10.sup.-2 Pa, and a deposition distance of 600 nm. The
glass substrate was maintained in a F.sub.2 gas atmosphere
(temperature 25.degree. C.) at pressure of 152 Torr for 10 minutes
to modify the surface of the protecting film, to form a fluoride
layer 55 of the protecting film. The thus-obtained glass substrate
was referred to as "Example 401".
EXAMPLE 402
[0279] A protecting film was formed on the surface of a glass
substrate by electron beam evaporation in the same manner as
Example 401, and the glass substrate was then maintained in a
F.sub.2 gas atmosphere (temperature 25.degree. C.) at pressure of
76 Torr for 10 minutes to modify the surface of the protecting
film, to form a fluoride layer on the surface of the protecting
film. The thus-obtained glass substrate was referred to as "Example
402".
EXAMPLE 403
[0280] A protecting film was formed on the surface of a glass
substrate by electron beam evaporation in the same manner as
Example 401, and the glass substrate was then maintained in a
F.sub.2 gas atmosphere (temperature 25.degree. C.) at pressure of
38 Torr for 1 minute to modify the surface of the protecting film,
to form a fluoride layer on the surface of the protecting film. The
thus-obtained glass substrate was referred to as "Example 403".
EXAMPLE 404
[0281] A protecting film was formed on the surface of a glass
substrate by electron beam evaporation in the same manner as
Example 401, and the glass substrate was then maintained in a
F.sub.2 gas atmosphere (temperature 25.degree. C.) at pressure of
38 Torr for 10 minutes to modify the surface of the protecting
film, to form a fluoride layer on the surface of the protecting
film. The thus-obtained glass substrate was referred to as "Example
404".
EXAMPLE 405
[0282] A protecting film was formed on the surface of a glass
substrate by electron beam evaporation in the same manner as
Example 401, and the glass substrate was then maintained in a
F.sub.2 gas atmosphere (temperature 25.degree. C.) at pressure of
38 Torr for 60 minutes to modify the surface of the protecting
film, to form a fluoride layer on the surface of the protecting
film. The thus-obtained glass substrate was referred to as "Example
405".
EXAMPLE 406
[0283] A protecting film was formed on the surface of a glass
substrate by electron beam evaporation in the same manner as
Example 401, and the glass substrate was then maintained in a
F.sub.2 gas atmosphere (temperature 25.degree. C.) at pressure of
7.6 Torr for 10 minutes to modify the surface of the protecting
film, to form a fluoride layer on the surface of the protecting
film. The thus-obtained glass substrate was referred to as "Example
406".
EXAMPLE 407
[0284] A protecting film was formed on the surface of a glass
substrate by electron beam evaporation in the same manner as
Example 401, and the glass substrate was then maintained in an
atmosphere (temperature 25.degree. C.) of a gas mixture containing
F.sub.2 gas at partial pressure of 7.6 Torr and N.sub.2 gas at
partial pressure of 752 Torr for 10 minutes to modify the surface
of the protecting film, to form a fluoride layer on the surface of
the protecting film. The thus-obtained glass substrate was referred
to as "Example 407".
EXAMPLE 408
[0285] A protecting film was formed on the surface of a glass
substrate by electron beam evaporation in the same manner as
Example 401, and the glass substrate was then maintained in a
F.sub.2 gas atmosphere (temperature 100.degree. C.) at pressure 7.6
Torr for 10 minutes to modify the surface of the protecting film,
to form a fluoride layer on the surface of the protecting film. The
thus-obtained glass substrate was referred to as "Example 408".
EXAMPLE 409
[0286] A protecting film was formed on the surface of a glass
substrate by electron beam evaporation in the same manner as
Example 401, and the glass substrate was then maintained in a HF
gas atmosphere (temperature 25.degree. C.) at pressure of 38 Torr
for 1 minute to modify the surface of the protecting film, to form
a fluoride layer on the surface of the protecting film. The
thus-obtained glass substrate was referred to as "Example 409".
EXAMPLE 410
[0287] A protecting film was formed on the surface of a glass
substrate by electron beam evaporation in the same manner as
Example 401, and the glass substrate was then maintained in an
atmosphere (temperature 25.degree. C.) of a gas mixture containing
HF gas at partial pressure of 7.6 Torr and N.sub.2 gas at partial
pressure of 752 Torr for 10 minutes to modify the surface of the
protecting film, to form a fluoride layer on the surface of the
protecting film. The thus-obtained glass substrate was referred to
as "Example 410".
EXAMPLE 411
[0288] A protecting film was formed on the surface of a glass
substrate by electron beam evaporation in the same manner as
Example 401, and the glass substrate was then maintained in a
BF.sub.3 gas atmosphere (temperature 25.degree. C.) at pressure of
7.6 Torr for 10 minutes to modify the surface of the protecting
film, to form a fluoride layer on the surface of the protecting
film. The thus-obtained glass substrate was referred to as "Example
411".
EXAMPLE 412
[0289] A protecting film was formed on the surface of a glass
substrate by electron beam evaporation in the same manner as
Example 401, and the glass substrate was then maintained in a
SbF.sub.5 gas atmosphere (temperature 25.degree. C.) at pressure of
7.6 Torr for 10 minutes to modify the surface of the protecting
film, to form a fluoride layer on the surface of the protecting
film. The thus-obtained glass substrate was referred to as "Example
412".
EXAMPLE 413
[0290] A protecting film was formed on the surface of a glass
substrate by electron beam evaporation in the same manner as
Example 401, and the glass substrate was then maintained in a
SF.sub.6 gas atmosphere (temperature 25.degree. C.) at pressure of
7.6 Torr for 10 minutes to modify the surface of the protecting
film, to form a fluoride layer on the surface of the protecting
film. The thus-obtained glass substrate was referred to as "Example
413".
EXAMPLE 414
[0291] After a glass substrate with electrodes was formed by the
same method as Example 401, a protecting film was formed on the
surface of the glass substrate by sputtering using a 5-inch size
MgO target having a purity of 99.99% (4N) to cover the surface of
the transparent dielectric layer of the glass substrate. The
deposition conditions for the protecting film includes a
high-frequency output of 1 kW, a sputtering pressure of 1.33 Pa, an
oxygen concentration of 10% relatively argon gas, and a substrate
temperature of 150.degree. C.
[0292] Next, the glass substrate was maintained in a F.sub.2 gas
atmosphere by the same method as Example 401 to modify the surface
of the protecting film, to form a fluoride layer on the surface of
the protecting film. The thus-obtained glass substrate was referred
to as "Example 414".
EXAMPLE 415
[0293] A protecting film was formed on the surface of a glass
substrate by sputtering in the same manner as Example 414, and the
glass substrate was then maintained in a HF gas atmosphere
(temperature 25.degree. C.) at pressure of 38 Torr for 1 minute to
modify the surface of the protecting film, to form a fluoride layer
on the surface of the protecting film. The thus-obtained glass
substrate was referred to as "Example 415".
EXAMPLE 416
[0294] First, display electrodes (thickness of 5 .mu.m) made of Ag
were formed on a front glass substrate having a thickness of 3 mm
by screen printing, and then the transparent dielectric layer
(thickness of 20 .mu.m) made of glass was formed thereon by screen
printing. Next, 79% by weight of organic acid magnesium (Magnesium
Naphthenate, produced by Nihon Kagaku Sangyo Co., ltd.) as a binder
containing a MgO component, 2% by weight of ethyl cellulose as a
binder containing no MgO component, and 19% by weight of
.alpha.-terpineol as a solvent were mixed to prepare MgO paste. The
thus-prepared MgO paste was coated on the glass substrate by screen
printing to form a protecting film.
[0295] Next, the glass substrate was dried by maintaining at
150.degree. C. in air for 30 minutes, and then burned by
maintaining at 550.degree. C. in air for 30 minutes. Furthermore,
the glass substrate was maintained in a F.sub.2 gas atmosphere
(temperature 25.degree. C.) at pressure of 152 Torr for 10 minutes
to modify the surface of the protecting film, to form a fluoride
layer on the surface of the protecting film. The thus-formed glass
substrate was referred to as "Example 416".
EXAMPLE 417
[0296] A protecting film was formed on the surface of a glass
substrate by screen printing in the same manner as Example 416,
dried and then burned. Then the glass substrate was maintained in a
HF gas atmosphere (temperature 25.degree. C.) at pressure of 38
Torr for 1 minute to modify the surface of the protecting, to form
a fluoride layer on the surface of the protecting film. The
thus-formed glass substrate was referred to as "Example 417".
EXAMPLE 418
[0297] 5% by weight of MgO powder (produced by Ube Materials)
produced by a vapor phase method and having an average particle
size of 100 .ANG., 75% by weight of organic acid magnesium
(Magnesium Naphthenate, produced by Nihon Kagaku Sangyo Co., ltd.)
and 2% by weight of ethyl cellulose as a binder for a MgO
component, and 18% by weight of .alpha.-terpineol as a solvent were
mixed to prepare MgO paste containing powder. The thus-prepared MgO
paste containing powder was used for forming a protecting film on
the glass substrate by the same method as Example 416. Furthermore,
the surface of the protecting film was modified to form a fluoride
layer on the surface thereof. The thus-formed glass substrate was
referred to as "Example 418".
EXAMPLE 419
[0298] First, display electrodes (thickness of 5 .mu.m) made of Ag
were formed on a front glass substrate having a thickness of 3 mm
by screen printing, and then a transparent dielectric layer
(thickness of 20 .mu.m) made of glass was formed thereon by screen
printing. Next, 1.25% by weight of magnesium diethoxide as a binder
containing a MgO component and 98.75% by weight of methyl
cellosolve as a solvent were mixed to prepare a uniform MgO coating
solution. The thus-prepared coating solution was coated on the
glass substrate by spin coating to form a protecting film.
[0299] Next, the glass substrate was dried by maintaining at
60.degree. C. in air for 30 minutes, and then burned by maintaining
at 580.degree. C. in air for 10 minutes. Furthermore, the glass
substrate was maintained in a F.sub.2 gas atmosphere (temperature
25.degree. C.) at pressure of 152 Torr for 10 minutes to modify the
surface of the protecting film, to form a fluoride layer on the
surface of the protecting film. The thus-formed glass substrate was
referred to as "Example 419".
EXAMPLE 420
[0300] A protecting film was formed on the surface of a glass
substrate by spin coating in the same manner as Example 419, dried
and then burned. Then the glass substrate was maintained in a HF
gas atmosphere (temperature 25.degree. C.) at pressure of 38 Torr
for 1 minute to modify the surface of the protecting, to form a
fluoride layer on the surface of the protecting film. The
thus-formed glass substrate was referred to as "Example 420".
EXAMPLE 421
[0301] 5% by weight of MgO powder (produced by Ube Materials)
produced by a vapor phase method and having an average particle
size of 100 .ANG., 1.25% by weight of magnesium diethoxide as a
binder for a MgO component, and 93.75% by weight of methyl
cellosolve as a solvent were mixed to prepare a uniform MgO coating
solution containing powder. The thus-prepared coating solution was
used for forming a protecting film on the glass substrate by the
same method as Example 419. Furthermore, the surface of the
protecting film was modified to form a fluoride layer on the
surface thereof. The thus-formed glass substrate was referred to as
"Example 421".
EXAMPLE 422
[0302] Using CaO sintered pellets having a purity of not less than
99.5%, CaO films were deposited by electron beam evaporation to
cover the surface of a transparent dielectric layer 17 of a glass
substrate to form a protecting film by the same method as Example
401. The glass substrate was further maintained in a HF gas
atmosphere (temperature 25.degree. C.) at pressure of 38 Torr for 1
minute to modify the surface of the protecting film by the same
method as Example 409, to form a fluoride layer on the surface of
the protecting film. The thus-formed glass substrate was referred
to as "Example 422".
EXAMPLE 423
[0303] A protecting film composed of SrO was formed by the same
method as Example 422 except that SrO sintered pellets having a
purity of not less than 99.5% were used, and the surface of the
protecting film was modified by the same method as Example 422 to
form a fluoride layer on the. surface of the protecting film. The
thus-formed glass substrate was referred to as "Example 423".
EXAMPLE 424
[0304] A protecting film composed of BaO was formed by the same
method as Example 422 except that BaO sintered pellets having a
purity of not less than 99.5% were used, and the surface of the
protecting film was modified by the same method as Example 422 to
form a fluoride layer on the surface of the protecting film. The
thus-formed glass substrate was referred to as "Example 424".
EXAMPLE 425
[0305] A protecting film composed of (Ca.Sr)O was formed by the
same method as Example 422 except that (Ca.Sr)O sintered pellets
having a purity of not less than 99.5% were used, and the surface
of the protecting film was modified by the same method as Example
422 to form a fluoride layer on the surface of the protecting film.
The thus-formed glass substrate was referred to as "Example
425".
EXAMPLE 426
[0306] A protecting film composed of (Mg.Sr)O was formed by the
same method as Example 422 except that (Mg.Sr)O sintered pellets
having a purity of not less than 99.5% were used, and the surface
of the protecting film was modified by the same method as Example
422 to form a fluoride layer on the surface of the protecting film.
The thus-formed glass substrate was referred to as "Example
426".
EXAMPLE 427
[0307] A protecting film composed of (Sr.Ba)O was formed by the
same method as Example 422 except that (Sr.Ba)O sintered pellets
having a purity of not less than 99.5% were used, and the surface
of the protecting film was modified by the same method as Example
422 to form a fluoride layer on the surface of the protecting film.
The thus-formed glass substrate was referred to as "Example
427".
EXAMPLE 428
[0308] A protecting film composed of Y.sub.2O.sub.3 was formed by
the same method as Example 422 except that Y.sub.2O.sub.3 sintered
pellets having a purity of not less than 99.5% were used, and the
surface of the protecting film was modified by the same method as
Example 422 to form a fluoride layer on the surface of the
protecting film. The thus-formed glass substrate was referred to as
"Example 428".
EXAMPLE 429
[0309] A protecting film composed of Gd.sub.2O.sub.3 was formed by
the same method as Example 422 except that Gd.sub.2O.sub.3 sintered
pellets having a purity of not less than 99.5% were used, and the
surface of the protecting film was modified by the same method as
Example 422 to form a fluoride layer on the surface of the
protecting film. The thus-formed glass substrate was referred to as
"Example 429".
EXAMPLE 430
[0310] A protecting film composed of Dy.sub.2O.sub.3 was formed by
the same method as Example 422 except that Dy.sub.2O.sub.3 sintered
pellets having a purity of not less than 99.5% were used, and the
surface of the protecting film was modified by the same method as
Example 422 to form a fluoride layer on the surface of the
protecting film. The thus-formed glass substrate was referred to as
"Example 430".
EXAMPLE 431
[0311] A protecting film composed of CeO.sub.2 was formed by the
same method as Example 422 except that CeO.sub.2 sintered pellets
having a purity of not less than 99.5% were used, and the surface
of the protecting film was modified by the same method as Example
422 to form a fluoride layer on the surface of the protecting film.
The thus-formed glass substrate was referred to as "Example
431".
EXAMPLE 432
[0312] A protecting film composed of La.sub.2O.sub.3 was formed by
the same method as Example 422 except that La.sub.2O.sub.3 sintered
pellets having a purity of not less than 99.5% were used, and the
surface of the protecting film was modified by the same method as
Example 422 to form a fluoride layer on the surface of the
protecting film. The thus-formed glass substrate was referred to as
"Example 432".
EXAMPLE 433
[0313] A protecting film composed of Yb.sub.2O.sub.3 was formed by
the same method as Example 422 except that Yb.sub.2O.sub.3 sintered
pellets having a purity of not less than 99.5% were used, and the
surface of the protecting film was modified by the same method as
Example 422 to form a fluoride layer on the surface of the
protecting film. The thus-formed glass substrate was referred to as
"Example 433".
EXAMPLE 434
[0314] A protecting film composed of MgGd.sub.2O.sub.4 was formed
by the same method as Example 422 except that MgGd.sub.2O.sub.4
sintered pellets having a purity of not less than 99.5% were used,
and the surface of the protecting film was modified by the same
method as Example 422 to form a fluoride layer on the surface of
the protecting film. The thus-formed glass substrate was referred
to as "Example 434".
EXAMPLE 435
[0315] A protecting film composed of MgY.sub.2O.sub.4 was formed by
the same method as Example 422 except that MgY.sub.2O.sub.4
sintered pellets having a purity of not less than 99.5% were used,
and the surface of the protecting film was modified by the same
method as Example 422 to form a fluoride layer on the surface of
the protecting film. The thus-formed glass substrate was referred
to as "Example 435".
EXAMPLE 436
[0316] A protecting film composed of MgLa.sub.2O.sub.4 was formed
by the same method as Example 422 except that MgLa.sub.2O.sub.4
sintered pellets having a purity of not less than 99.5% were used,
and the surface of the protecting film was modified by the same
method as Example 422 to form a fluoride layer on the surface of
the protecting film. The thus-formed glass substrate was referred
to as "Example 436".
EXAMPLE 437
[0317] A protecting film composed of CaGd.sub.2O.sub.4 was formed
by the same method as Example 422 except that CaGd.sub.2O.sub.4
sintered pellets having a purity of not less than 99.5% were used,
and the surface of the protecting film was modified by the same
method as Example 422 to form a fluoride layer on the surface of
the protecting film. The thus-formed glass substrate was referred
to as "Example 437".
EXAMPLE 438
[0318] A protecting film composed of CaY.sub.2O.sub.4 was formed by
the same method as Example 422 except that CaY.sub.2O.sub.4
sintered pellets having a purity of not less than 99.5% were used,
and the surface of the protecting film was modified by the same
method as Example 422 to form a fluoride layer on the surface of
the protecting film. The thus-formed glass substrate was referred
to as "Example 438".
EXAMPLE 439
[0319] A protecting film composed of CaLa.sub.2O.sub.4 was formed
by the same method as Example 422 except that CaLa.sub.2O.sub.4
sintered pellets having a purity of not less than 99.5% were used,
and the surface of the protecting film was modified by the same
method as Example 422 to form a fluoride layer on the surface of
the protecting film. The thus-formed glass substrate was referred
to as "Example 439".
EXAMPLE 440
[0320] A protecting film composed of SrGd.sub.2O.sub.4 was formed
by the same method as Example 422 except that SrGd.sub.2O.sub.4
sintered pellets having a purity of not less than 99.5% were used,
and the surface of the protecting film was modified by the same
method as Example 422 to form a fluoride layer on the surface of
the protecting film. The thus-formed glass substrate was referred
to as "Example 440".
EXAMPLE 441
[0321] A protecting film composed of SrY.sub.2O.sub.4 was formed by
the same method as Example 422 except that SrY.sub.2O.sub.4
sintered pellets having a purity of not less than 99.5% were used,
and the surface of the protecting film was modified by the same
method as Example 422 to form a fluoride layer on the surface of
the protecting film. The thus-formed glass substrate was referred
to as "Example 441".
EXAMPLE 442
[0322] A protecting film composed of SrLa.sub.2O.sub.4 was formed
by the same method as Example 422 except that SrLa.sub.2O.sub.4
sintered pellets having a purity of not less than 99.5% were used,
and the surface of the protecting film was modified by the same
method as Example 422 to form a fluoride layer on the surface of
the protecting film. The thus-formed glass substrate was referred
to as "Example 442".
EXAMPLE 443
[0323] A protecting film composed of BaGd.sub.2O.sub.4 was formed
by the same method as Example 422 except that BaGd.sub.2O.sub.4
sintered pellets having a purity of not less than 99.5% were used,
and the surface of the protecting film was modified by the same
method as Example 422 to form a fluoride layer on the surface of
the protecting film. The thus-formed glass substrate was referred
to as "Example 443".
EXAMPLE 444
[0324] A protecting film composed of BaY.sub.2O.sub.4 was formed by
the same method as Example 422 except that BaY.sub.2O.sub.4
sintered pellets having a purity of not less than 99.5% were used,
and the surface of the protecting film was modified by the same
method as Example 422 to form a fluoride layer on the surface of
the protecting film. The thus-formed glass substrate was referred
to as "Example 444".
EXAMPLE 445
[0325] A protecting film composed of BaLa.sub.2O.sub.4 was formed
by the same method as Example 422 except that BaLa.sub.2O.sub.4
sintered pellets having a purity of not less than 99.5% were used,
and the surface of the protecting film was modified by the same
method as Example 422 to form a fluoride layer on the surface of
the protecting film. The thus-formed glass substrate was referred
to as "Example 445".
EXAMPLE 446
[0326] A protecting film composed of MaO:LaB.sub.6 was formed by
the same method as Example 422 except that MaO:LaB.sub.6 sintered
pellets having a purity of not less than 99.5% were used, and the
surface of the protecting film was modified by the same method as
Example 422 to form a fluoride layer on the surface of the
protecting film. The thus-formed glass substrate was referred to as
"Example 446".
EXAMPLE 447
[0327] A protecting film composed of MaO:La.sub.2O.sub.3 was formed
by the same method as Example 422 except that MgO:La.sub.2O.sub.3
sintered pellets having a purity of not less than 99.5% were used,
and the surface of the protecting film was modified by the same
method as Example 422 to form a fluoride layer on the surface of
the protecting film. The thus-formed glass substrate was referred
to as "Example 447".
EXAMPLE 448
[0328] A protecting film composed of MaO:Sc.sub.2O.sub.3 was formed
by the same method as Example 422 except that MgO:Sc.sub.2O.sub.3
sintered pellets having a purity of not less than 99.5% were used,
and the surface of the protecting film was modified by the same
method as Example 422 to form a fluoride layer on the surface of
the protecting film. The thus-formed glass substrate was referred
to as "Example 448".
EXAMPLE 449
[0329] A protecting film composed of MaO:Y.sub.2O.sub.3 was formed
by the same method as Example 422 except that MgO:Y.sub.2O.sub.3
sintered pellets having a purity of not less than 99.5% were used,
and the surface of the protecting film was modified by the same
method as Example 422 to form a fluoride layer on the surface of
the protecting film. The thus-formed glass substrate was referred
to as "Example 449".
COMPARATIVE EXAMPLE 401
[0330] A protecting film was formed on the surface of a glass
substrate by electron beam evaporation in same manner as Example
401 except that the surface of the protecting film was not
modified. The thus-formed glass substrate was referred to as
"Comparative Example 401".
COMPARATIVE EXAMPLE 402
[0331] A protecting film was formed on the surface of a glass
substrate by sputtering in same manner as Example 414 except that
the surface of the protecting film was not modified. The
thus-formed glass substrate was referred to as "Comparative Example
402".
COMPARATIVE EXAMPLE 403
[0332] A protecting film was formed on the surface of a glass
substrate by screen printing, dried and then burned in same manner
as Example 416 except that the surface of the protecting film was
not modified. The thus-formed glass substrate was referred to as
"Comparative Example 403".
COMPARATIVE EXAMPLE 404
[0333] A protecting film was formed on the surface of a glass
substrate by screen printing, dried and then burned in same manner
as Example 418 except that the surface of the protecting film was
not modified. The thus-formed glass substrate was referred to as
"Comparative Example 404".
COMPARATIVE EXAMPLE 405
[0334] A protecting film was formed on the surface of a glass
substrate by spin coating, dried and then burned in same manner as
Example 419 except that the surface of the protecting film was not
modified. The thus-formed glass substrate was referred to as
"Comparative Example 405".
COMPARATIVE EXAMPLE 406
[0335] A protecting film was formed on the surface of a glass
substrate by spin coating, dried and then burned in same manner as
Example 421 except that the surface of the protecting film was not
modified. The thus-formed glass substrate was referred to as
"Comparative Example 406".
COMPARATIVE EXAMPLE 407
[0336] CaO sintered pellets having a purity of not less than 99.5%
were deposited by electron beam evaporation to cover the surface of
a transparent dielectric layer of a glass substrate to form a
protecting film composed of CaO by the same method as Example 401
except that the surface of the protecting film was not modified.
The thus-formed glass substrate was referred to as "Comparative
Example 407".
COMPARATIVE EXAMPLE 408
[0337] A protecting film composed of SrO was formed by the same
method as Comparative Example 407 except that SrO sintered pellets
having a purity of not less than 99.5% were used, to form a glass
substrate. The thus-formed glass substrate was referred to as
"Comparative Example 408".
COMPARATIVE EXAMPLE 409
[0338] A protecting film composed of BaO was formed by the same
method as Comparative Example 407 except that BaO sintered pellets
having a purity of not less than 99.5% were used, to form a glass
substrate. The thus-formed glass substrate was referred to as
"Comparative Example 409".
COMPARATIVE EXAMPLE 410
[0339] A protecting film composed of (Ca.Sr)O was formed by the
same method as Comparative Example 407 except that (Ca.Sr)O
sintered pellets having a purity of not less than 99.5% were used,
to form a glass substrate. The thus-formed glass substrate was
referred to as "Comparative Example 410".
COMPARATIVE EXAMPLE 411
[0340] A protecting film composed of (Mg.Sr)O was formed by the
same method as Comparative Example 407 except that (Mg.Sr)O
sintered pellets having a purity of not less than 99.5% were used,
to form a glass substrate. The thus-formed glass substrate was
referred to as "Comparative Example 411".
COMPARATIVE EXAMPLE 412
[0341] A protecting film composed of (Sr.Ba)O was formed by the
same method as Comparative Example 407 except that (Sr.Ba)O
sintered pellets having a purity of not less than 99.5% were used,
to form a glass substrate. The thus-formed glass substrate was
referred to as "Comparative Example 412".
COMPARATIVE EXAMPLE 413
[0342] A protecting film composed of Y.sub.2O.sub.3 was formed by
the same method as Comparative Example 407 except that
Y.sub.2O.sub.3 sintered pellets having a purity of not less than
99.5% were used, to form a glass substrate. The thus-formed glass
substrate was referred to as "Comparative Example 413".
COMPARATIVE EXAMPLE 414
[0343] A protecting film composed of Gd.sub.2O.sub.3 was formed by
the same method as Comparative Example 407 except that
Gd.sub.2O.sub.3 sintered pellets having a purity of not less than
99.5% were used, to form a glass substrate. The thus-formed glass
substrate was referred to as "Comparative Example 414".
COMPARATIVE EXAMPLE 415
[0344] A protecting film composed of Dy.sub.2O.sub.3 was formed by
the same method as Comparative Example 407 except that
Dy.sub.2O.sub.3 sintered pellets having a purity of not less than
99.5% were used, to form a glass substrate. The thus-formed glass
substrate was referred to as "Comparative Example 415".
COMPARATIVE EXAMPLE 416
[0345] A protecting film composed of CeO.sub.2 was formed by the
same method as Comparative Example 407 except that CeO.sub.2
sintered pellets having a purity of not less than 99.5% were used,
to form a glass substrate. The thus-formed glass substrate was
referred to as "Comparative Example 416".
COMPARATIVE EXAMPLE 417
[0346] A protecting film composed of La.sub.2O.sub.3 was formed by
the same method as Comparative Example 407 except that
La.sub.2O.sub.3 sintered pellets having a purity of not less than
99.5% were used, to form a glass substrate. The thus-formed glass
substrate was referred to as "Comparative Example 417".
COMPARATIVE EXAMPLE 418
[0347] A protecting film composed of Yb.sub.2O.sub.3 was formed by
the same method as Comparative Example 407 except that
Yb.sub.2O.sub.3 sintered pellets having a purity of not less than
99.5% were used, to form a glass substrate. The thus-formed glass
substrate was referred to as "Comparative Example 418".
COMPARATIVE EXAMPLE 419
[0348] A protecting film composed of MgGd.sub.2O.sub.4 was formed
by the same method as Comparative Example 407 except that
MgGd.sub.2O.sub.4 sintered pellets having a purity of not less than
99.5% were used, to form a glass substrate. The thus-formed glass
substrate was referred to as "Comparative Example 419".
COMPARATIVE EXAMPLE 420
[0349] A protecting film composed of MgY.sub.2O.sub.4 was formed by
the same method as Comparative Example 407 except that
MgY.sub.2O.sub.4 sintered pellets having a purity of not less than
99.5% were used, to form a glass substrate. The thus-formed glass
substrate was referred to as "Comparative Example 420".
COMPARATIVE EXAMPLE 421
[0350] A protecting film composed of MgLa.sub.2O.sub.4 was formed
by the same method as Comparative Example 407 except that
MgLa.sub.2O.sub.4 sintered pellets having a purity of not less than
99.5% were used, to form a glass substrate. The thus-formed glass
substrate was referred to as "Comparative Example 421".
COMPARATIVE EXAMPLE 422
[0351] A protecting film composed of CaGd.sub.2O.sub.4 was formed
by the same method as Comparative Example 407 except that
CaGd.sub.2O.sub.4 sintered pellets having a purity of not less than
99.5% were used, to form a glass substrate. The thus-formed glass
substrate was referred to as "Comparative Example 422".
COMPARATIVE EXAMPLE 423
[0352] A protecting film composed of CaY.sub.2O.sub.4 was formed by
the same method as Comparative Example 407 except that
CaY.sub.2O.sub.4 sintered pellets having a purity of not less than
99.5% were used, to form a glass substrate. The thus-formed glass
substrate was referred to as "Comparative Example 423".
COMPARATIVE EXAMPLE 424
[0353] A protecting film composed of CaLa.sub.2O.sub.4 was formed
by the same method as Comparative Example 407 except that
Cala.sub.2O.sub.4 sintered pellets having a purity of not less than
99.5% were used, to form a glass substrate. The thus-formed glass
substrate was referred to as "Comparative Example 424".
COMPARATIVE EXAMPLE 425
[0354] A protecting film composed of SrGd.sub.2O.sub.4 was formed
by the same method as Comparative Example 407 except that
SrGd.sub.2O.sub.4 sintered pellets having a purity of not less than
99.5% were used, to form a glass substrate. The thus-formed glass
substrate was referred to as "Comparative Example 425".
COMPARATIVE EXAMPLE 426
[0355] A protecting film composed of SrY.sub.2O.sub.4 was formed by
the same method as Comparative Example 407 except that
SrY.sub.2O.sub.4 sintered pellets having a purity of not less than
99.5% were used, to form a glass substrate. The thus-formed glass
substrate was referred to as "Comparative Example 426".
COMPARATIVE EXAMPLE 427
[0356] A protecting film composed of SrLa.sub.2O.sub.4 was formed
by the same method as Comparative Example 407 except that
SrLa.sub.2O.sub.4 sintered pellets having a purity of not less than
99.5% were used, to form a glass substrate. The thus-formed glass
substrate was referred to as "Comparative Example 427".
COMPARATIVE EXAMPLE 428
[0357] A protecting film composed of BaGd.sub.2O.sub.4 was formed
by the same method as Comparative Example 407 except that
BaGd.sub.2O.sub.4 sintered pellets having a purity of not less than
99.5% were used, to form a glass substrate. The thus-formed glass
substrate was referred to as "Comparative Example 428".
COMPARATIVE EXAMPLE 429
[0358] A protecting film composed of BaY.sub.2O.sub.4 was formed by
the same method as Comparative Example 407 except that
BaY.sub.2O.sub.4 sintered pellets having a purity of not less than
99.5% were used, to form a glass substrate. The thus-formed glass
substrate was referred to as "Comparative Example 429".
COMPARATIVE EXAMPLE 430
[0359] A protecting film composed of BaLa.sub.2O.sub.4 was formed
by the same method as Comparative Example 407 except that
BaLa.sub.2O.sub.4 sintered pellets having a purity of not less than
99.5% were used, to form a glass substrate. The thus-formed glass
substrate was referred to as "Comparative Example 430".
COMPARATIVE EXAMPLE 431
[0360] A protecting film composed of MgO:LaB.sub.6 was formed by
the same method as Comparative Example 407 except that
MgO:LaB.sub.6 sintered pellets having a purity of not less than
99.5% were used, to form a glass substrate. The thus-formed glass
substrate was referred to as "Comparative Example 431".
COMPARATIVE EXAMPLE 432
[0361] A protecting film composed of MgO:La.sub.2O.sub.3 was formed
by the same method as Comparative Example 407 except that
MgO:La.sub.2O.sub.3 sintered pellets having a purity of not less
than 99.5% were used, to form a glass substrate. The thus-formed
glass substrate was referred to as "Comparative Example 432".
COMPARATIVE EXAMPLE 433
[0362] A protecting film composed of MgO:Sc.sub.2O.sub.3 was formed
by the same method as Comparative Example 407 except that
MgO:Sc.sub.2O.sub.3 sintered pellets having a purity of not less
than 99.5% were used, to form a glass substrate. The thus-formed
glass substrate was referred to as "Comparative Example 433".
COMPARATIVE EXAMPLE 434
[0363] A protecting film composed of MgO:Y.sub.2O.sub.3 was formed
by the same method as Comparative Example 407 except that
MgO:Y.sub.2O.sub.3 sintered pellets having a purity of not less
than 99.5% were used, to form a glass substrate. The thus-formed
glass substrate was referred to as "Comparative Example 434".
COMPARISON TEST 8 AND EVALUATION
[0364] In each of Examples 401 to 449, the thickness of the
fluoride layer formed on the surface of the protecting film on the
front glass substrate was measured by elemental analysis in the
depth direction by X-ray photoelectron spectroscopy.
[0365] In each of Examples 401 to 449 and Comparative Examples 401
to 434, the environment resistance of the protecting films was
measured by the same method as Comparison Test 1.
[0366] In each of Examples 401 to 449 and Comparative Examples 401
to 434, the breakdown voltage (Vf) of the protecting film was
measured as follows:
[0367] In Examples 401 to 449, the glass substrate was first
incorporated in PDP, a removal discharge gas (gas containing
CF.sub.4) was injected in each of the discharge cells of the PDP,
and then plane discharge was started between the display electrodes
to remove the fluoride layer by etching due to the discharge. After
the removal discharge gas was exhausted, the panel was filled with
a gas mixture of He and 2% Xe at 400 Torr as a display discharge
gas. In this state, an AC voltage of 10 kHz was applied between the
display electrodes to measure the breakdown voltage.
[0368] In Comparative Examples 401 to 434, the glass substrate was
first incorporated in PDP, and each of the discharge cells of the
PDP was filled with a gas mixture of He and 2% Xe at 400 Torr as a
display discharge gas. In this state, an AC voltage of 10 kHz was
applied between the display electrodes to measure the breakdown
voltage.
[0369] The results of measurement are shown in Tables 15 to 19.
15 TABLE 15 Environment Modification condition of film body (MgO)
Thickness resistance surface of Thickness Break- Type and partial
pressure of gas fluoride of down Example Temperature Time Partial
Partial layer carbonate voltage No. (.degree. C.) (min) Gas
pressure Gas pressure (nm) (nm) Vf (V) 401 25 10 F.sub.2 152 -- --
24 1 156 401 25 10 F.sub.2 152 -- -- 24 1 156 402 25 10 F.sub.2 76
-- -- 16 1 154 403 25 1 F.sub.2 38 -- -- 10 3 160 404 25 10 F.sub.2
38 -- -- 15 1 152 405 25 60 F.sub.2 38 -- -- 30 1 156 406 25 10
F.sub.2 7.6 -- -- 5 7 166 407 25 10 F.sub.2 7.6 N.sub.2 752 6 10
165 408 100 10 F.sub.2 7.6 -- -- 22 1 152 409 25 1 HF 38 -- -- 5 12
166 410 25 10 HF 7.6 N.sub.2 752 2 15 168 411 25 10 BF.sub.3 7.6 --
-- 4 10 163 412 25 10 SbF.sub.5 7.6 -- -- 5 7 159 413 25 10
SF.sub.4 7.6 -- -- 2 11 165 414 25 10 F.sub.2 152 -- -- 10 1 151
415 25 1 HF 38 -- -- 2 7 156 416 25 10 F.sub.2 152 -- -- 36 2 170
417 25 1 HF 38 -- -- 6 15 178 418 25 10 F.sub.2 152 -- -- 420 5 171
419 25 10 F.sub.2 152 -- -- 42 2 173 420 25 1 HF 38 -- -- 6 18 180
421 25 10 F.sub.2 152 -- -- 510 7 178
[0370]
16 TABLE 16 Environ- Thick- ment Modification condition of ness
resistance protecting film surface of Thickness Break- Type of Type
Partial fluoride of down Example sintered Temperature Time of
pressure layer carbonate voltage No. pellets (.degree. C.) (min)
gas of gas (nm) (nm) Vf (V) 422 CaO 25 1 HF 38 10 8 170 423 SrO 16
1 156 424 BaO 15 1 161 425 (Ca.Sr)O 12 2 151 426 (Mg.Sr)O 10 2 150
427 (Sr.Ba)O 16 1 154 428 Y.sub.2O.sub.3 8 2 190 429
Gd.sub.2O.sub.3 6 1 183 430 Dy.sub.2O.sub.3 5 2 180 431 CeO.sub.2
10 2 183 432 La.sub.2O.sub.3 7 4 171 433 Yb.sub.2O.sub.3 7 3 173
434 MgGd.sub.2O.sub.4 7 3 180 435 MgY.sub.2O.sub.4 8 3 173
[0371]
17 TABLE 17 Environ- Thick- ment Modification condition of ness
resistance protecting film surface of Thickness Break- Type of Type
Partial fluoride of down Example sintered Temperature Time of
pressure layer carbonate voltage No. pellets (.degree. C.) (min)
gas of gas (nm) (nm) Vf (V) 446 MgLa.sub.2O.sub.4 25 1 HF 38 6 2
170 437 CaGd.sub.2O.sub.4 5 1 183 438 CaY.sub.2O.sub.4 7 1 177 439
CaLa.sub.2O.sub.4 9 2 177 440 SrGd.sub.2O.sub.4 10 4 164 441
SrY.sub.2O.sub.4 10 4 163 442 SrLa.sub.2O.sub.4 12 3 170 443
BaGd.sub.2O.sub.4 15 3 171 444 BaY.sub.2O.sub.4 18 1 175 445
BaLa.sub.2O.sub.4 16 1 171 446 MaO: 10 2 155 LaB.sub.6 447 MgO: 8 4
156 La.sub.2O.sub.3 448 MgO: 12 5 153 Sc.sub.2O.sub.3 449 MgO: 12 2
153 Y.sub.2O.sub.3
[0372]
18TABLE 18 Environ- Thick- ment Modification condition of ness
resistance Compara- protecting film surface of Thickness Break-
tive Type of Type Partial fluoride of down Example sintered
Temperature Time of pressure layer carbonate voltage No. pellets
(.degree. C.) (min) gas of gas (nm) (nm) Vf (V) 401 MgO -- -- -- --
Un- 17 172 402 MgO treated 10 165 403 MgO 22 196 404 MgO 510 201
405 MgO 30 195 406 MgO 560 200 407 CaO 20 180 408 SrO 22 185 409
BaO 28 186 410 (Ca.Sr)O 25 179 411 (Mg.Sr)O 22 176 412 (Sr.Ba)O 25
191 413 Y.sub.2O.sub.3 18 213 414 Gd.sub.2O.sub.3 20 206 415
Dy.sub.2O.sub.3 25 200 416 CeO.sub.2 16 198 417 La.sub.2O.sub.3 19
190
[0373]
19TABLE 19 Environ- Thick- ment Modification condition of ness
resistance Compara- protecting film surface of Thickness Break-
tive Type of Type Partial fluoride of down Example sintered
Temperature Time of pressure layer carbonate voltage No. pellets
(.degree. C.) (min) gas of gas (nm) (nm) Vf (V) 418 Yb.sub.2O.sub.3
-- -- -- -- Un- 26 208 419 MgGd.sub.2O.sub.4 treated 16 212 420
MgY.sub.2O.sub.4 18 190 421 MgLa.sub.2O.sub.4 26 185 422
CaGd.sub.2O.sub.4 14 187 423 CaY.sub.2O.sub.4 16 189 424
CaLa.sub.2O.sub.4 20 192 425 SrGd.sub.2O.sub.4 22 192 426
SrY.sub.2O.sub.4 27 185 427 SrLa.sub.2O.sub.4 18 195 428
BaGd.sub.2O.sub.4 16 202 429 BaY.sub.2O.sub.4 14 201 430
BaLa.sub.2O.sub.4 24 206 431 MaO: 18 188 LaB.sub.6 432 MgO: 14 180
La.sub.2O.sub.3 433 MgO: 16 182 Sc.sub.2O.sub.3 434 MgO: 16 186
Y.sub.2O.sub.3
[0374] Tables 15 to 19 indicate that in each of Comparative
Examples 401 to 403, 405, and 407 to 434, the thickness of the
carbonate (MgCO.sub.3) formed on the film body is as large as 10 to
30 nm, and in each of Comparative Examples 404 and 406, the
carbonate (MgCO.sub.3) is formed over substantially the entire
protecting film. On the other hand, in each of Examples 401 to 449,
the thickness of the carbonate is as small as 1 to 18 nm. It is
also found that as the thickness of the fluoride layer formed on
the surface of the protecting film increases, the thickness of the
carbonate layer decreases.
[0375] In Comparative Examples 401 and 402, the breakdown voltages
are 172 and 165 V, respectively, while in Examples 401 to 415
corresponding to Comparative Examples 401 and 402, the breakdown
voltages are slightly lower values of 151 to 168 V. In Comparative
Examples 403 to 406, the breakdown voltages are 195 to 201 V, while
in Examples 416 to 421 corresponding to Comparative Examples 403 to
406, the breakdown voltages are as low as 170 to 180 V. In
Comparative Examples 407 to 434, the breakdown voltages are 176 to
213 V, while in Examples 422 to 449 corresponding to Comparative
Examples 407 to 434, the breakdown voltages are as low as 150 to
190 V. It is thus found that in Examples of the present invention,
the secondary electron emitting ability is high, and thus the
performance of PDP is improved.
[0376] As described above, in the present invention, a film body is
formed on the surface of a substrate, and a fluoride layer is
further formed on the surface of the film body. Therefore, even
when a protecting film is exposed to air for a long time during the
process for manufacturing FPD, MgO or the like in the film body
little reacts with CO.sub.2 gas and H.sub.2O gas in air. As a
result, MgO or the like is little degenerated to MgCO.sub.3 and
Mg(OH).sub.2, etc. which have the probability of deteriorating the
function of FPD, thereby improving the environment resistance of
the film body.
[0377] Since the film body of the protecting film, which has
substantially the same thermal expansion coefficient as the
substrate, is bonded to the substrate, the protecting film is not
separated from the substrate due to a thermal cycle, and adhesion
and matching between the protecting film and the substrate are
significantly improved.
[0378] In the protecting film comprising the film body formed on
the surface of the substrate by using a MgO powder or the like
coated with a fluoride layer, even when the protecting film is
exposed to air for a long time during the process for manufacturing
FPD, MgO or the like in the film body little reacts with CO.sub.2
gas and H.sub.2O gas in air. As a result, MgO or the like is little
degenerated to MgCO.sub.3 and Mg(OH).sub.2, etc. which have the
probability of deteriorating the function of FPD, thereby improving
the environment resistance of the film body. In addition, since the
fluoride layers coated on the surfaces of the MgO powder or the
like are very thin, the MgO powder or the like has substantially
the same mechanical properties as a MgO powder or the like with no
fluoride layer coated on the surfaces thereof.
[0379] Furthermore, where the fluoride layer is represented by
MO.sub.XF.sub.Y (M is Mg, or the like, 0.ltoreq.X<2, and
0<Y.ltoreq.4); the fluoride layer is obtained by reaction of a
gaseous fluorinating agent with MgO or the like; fluorine gas,
hydrogen fluoride gas, BF.sub.3, SbF.sub.5 or SF.sub.4 is used as
the gaseous fluorinating agent; or the thickness of the fluoride
layer is set in the range of 0.1 to 1000 nm; the above effect can
be significantly exhibited.
[0380] The film body may be formed on the surface of the substrate
and then surface-treated with a gaseous fluorinating agent to form
a fluoride layer on the surface of the film body. In this case, MgO
or the like in the film body is little degenerated to MgCO.sub.3
and Mg(OH).sub.2, etc. which are harmful to the function of FPD,
thereby shortening the time of the subsequent degassing step for
removing MgCO.sub.3 and Mg(OH).sub.2, etc. or omitting the
degassing step, decreasing the manufacturing cost of FPD.
[0381] The film body may be formed on the surface of the substrate
in a vacuum, and then surface-treated with a gaseous fluorinating
agent in a vacuum or an inert gas atmosphere without exposure to
air to form a fluoride layer on the surface of the film body. This
can prevent or suppress the production of carbonate (MgCO.sub.3 or
the like) and hydroxide (Mg(OH).sub.2 or the like) of MgO or the
like, which are harmful to FPD, on the surface of the film
body.
[0382] The film body may be formed on the substrate of the
substrate in a vacuum, exposed to air and then activated by burning
in air, and further surface-treated with a gaseous fluorinating
agent to form a fluoride layer on the surface of the film body. In
this case, even when carbonate (MgCO.sub.3 or the like) and
hydroxide (Mg(OH).sub.2 or the like) of MgO or the like, which are
harmful to FPD, are formed on the surface of the film body, the
film body is activated by burning to remove carbonate (MgCO.sub.3
or the like) and hydroxide (Mg(OH).sub.2 or the like) of MgO or the
like, which are formed on the surface of the film body, as CO.sub.2
and H.sub.2O. In this state, the fluoride layer is formed on the
surface of the film body to protect the surface of the film body by
the fluoride layer, thereby preventing or suppressing the formation
of carbonate (MgCO.sub.3 or the like) and hydroxide (Mg(OH).sub.2
or the like) of MgO or the like. The formation of carbonate and
hydroxide of MgO or the like can be significantly prevented or
suppressed by fluorination without exposure to air after MgO or the
like is deposited in a vacuum.
[0383] The substrate surface on which the film body and the
fluoride layer are formed may be burned in air before, during or
after assembly to activate the film body. In this case, when
hydroxide (Mg(OH).sub.2 or the like) of MgO or the like is slightly
formed on the film body, the hydroxide can be removed as H.sub.2O,
thereby decreasing the rate of recontamination of the film body
with atmospheric moisture.
[0384] The film body may be formed on the surface of the substrate
by using paste or dispersion for a film which is prepared by mixing
a binder and a MgO powder or the like coated with a fluoride layer
by surface-treating the MgO powder or the like with a gaseous
fluorinating agent. In this case, since the MgO powder or the like
in the film body is little degenerated to MgCO.sub.3 and
Mg(OH).sub.2, etc. which are harmful to the function of FPD,
thereby shortening the time of the subsequent degassing step for
removing MgCO.sub.3 and Mg(OH).sub.2, etc. or omitting the
degassing step, decreasing the manufacturing cost of FPD, as
described above.
[0385] Where the film body or MgO powder or the like is
surface-treated with a gaseous fluorinating agent at pressure of 1
to 760 Torr; or fluorine gas, hydrogen fluoride gas, BF.sub.3,
SbF.sub.5 or SF.sub.4 is used as the gaseous fluorinating agent; it
is possible to relatively easily form the fluoride layer having the
high secondary-electron emitting ability on the surface of the film
body or the MgO powder or the like.
[0386] In manufacturing FPD by using the above-mentioned protecting
film, the number of steps for manufacturing FPD can be
significantly decreased, and thus FPD can be manufactured at low
cost.
[0387] The protecting film composed of an alkali earth metal oxide
or the like may be formed on the surface of the substrate, and then
surface-treated with a gaseous fluorinating agent to form a
fluoride layer on the surface of the protecting film, followed by
removal of the fluoride layer after assembly of FPD using the
substrate. In this case, even when the protecting film is exposed
to air for a long time in the process for manufacturing FPD, the
protecting film little reacts with CO.sub.2 gas and H.sub.2O gas in
air. As a result, the alkali earth metal oxide or the like of the
protecting film is little degenerated to carbonate and hydroxide,
etc. which have the probability of deteriorating the function of
FPD, thereby improving the environment resistance of the protecting
film. On the other hand, the occurrence of cracks in the fluoride
layer and separation of the fluoride layer can be prevented due to
good matching between the fluoride layer and the protecting layer,
thereby improving the degeneration protecting effect of the
protecting film.
[0388] Furthermore, where the fluoride layer is represented by
MO.sub.XF.sub.Y (M is an alkali earth metal, or the like,
0.ltoreq.X<2, and 0<Y.ltoreq.4); the fluoride layer is
obtained by reaction of a gaseous fluorinating agent with an alkali
earth metal or the like; fluorine gas, hydrogen fluoride gas,
BF.sub.3, SbF.sub.5 or SF.sub.4 is used as the gaseous fluorinating
agent; or the thickness of the fluoride layer is set in the range
of 0.1 to 1000 nm; the above effect can be significantly
exhibited.
[0389] In the protecting film and FPD produced by the
above-mentioned method, the fluoride layer is removed after
assembly of FPD, improving the discharge characteristics of
FPD.
* * * * *