U.S. patent application number 13/554289 was filed with the patent office on 2013-01-24 for low reflection glass and protective plate for display.
This patent application is currently assigned to ASAHI GLASS COMPANY LIMITED. The applicant listed for this patent is Makoto FUKAWA, Shinsuke KAGA, Kenichi TANAKA. Invention is credited to Makoto FUKAWA, Shinsuke KAGA, Kenichi TANAKA.
Application Number | 20130022798 13/554289 |
Document ID | / |
Family ID | 41216932 |
Filed Date | 2013-01-24 |
United States Patent
Application |
20130022798 |
Kind Code |
A1 |
FUKAWA; Makoto ; et
al. |
January 24, 2013 |
LOW REFLECTION GLASS AND PROTECTIVE PLATE FOR DISPLAY
Abstract
Provided is a low reflection glass excellent in the abrasion
resistance, the weather resistance, and the productivity. A low
reflection glass includes a glass substrate and an antireflection
film formed on the surface of the glass substrate. The
antireflection film includes an interlayer and an outermost layer.
The outermost layer contains Si atoms, C atoms and O atoms, and the
content of C atoms is from 0.5 to 3 mol. % based on 100 mol. % of
the total amount of Si, C and O atoms. The interlayer is a high
refractive index layer or a light absorbing layer. Also provides is
a protective plate for a display including a support substrate
including the low reflection glass and a conductive film provided
on a side where no antireflection film is formed of the support
substrate.
Inventors: |
FUKAWA; Makoto; (Tokyo,
JP) ; TANAKA; Kenichi; (Tokyo, JP) ; KAGA;
Shinsuke; (Tokyo, JP) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
FUKAWA; Makoto
TANAKA; Kenichi
KAGA; Shinsuke |
Tokyo
Tokyo
Tokyo |
|
JP
JP
JP |
|
|
Assignee: |
ASAHI GLASS COMPANY LIMITED
Tokyo
JP
|
Family ID: |
41216932 |
Appl. No.: |
13/554289 |
Filed: |
July 20, 2012 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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12907071 |
Oct 19, 2010 |
8287994 |
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13554289 |
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PCT/JP09/58134 |
Apr 24, 2009 |
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12907071 |
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Current U.S.
Class: |
428/212 ;
428/426; 428/433 |
Current CPC
Class: |
C03C 2217/734 20130101;
C03C 17/3441 20130101; C03C 27/048 20130101; Y10T 428/24942
20150115; G02B 1/11 20130101; Y10T 428/31786 20150401; C03C 2217/78
20130101 |
Class at
Publication: |
428/212 ;
428/426; 428/433 |
International
Class: |
B32B 17/00 20060101
B32B017/00; B32B 17/06 20060101 B32B017/06; B32B 7/02 20060101
B32B007/02 |
Foreign Application Data
Date |
Code |
Application Number |
Apr 24, 2008 |
JP |
2008-113857 |
Claims
1. A low reflection glass comprising a glass substrate and an
antireflection film formed on the surface of the glass substrate,
wherein the antireflection film comprises an interlayer and an
outermost layer disposed in this order from the glass substrate
side; and the outermost layer is a layer containing Si atoms, C
atoms and O atoms, the content of C atoms being from 0.5 to 3 mol %
based on 100 mol % of the total amount of Si atoms, C atoms and O
atoms, and the interlayer is the following layer (a) or layer (b):
layer (a): a layer having an extinction coefficient K.sub.1 at a
wavelength of from 380 to 780 nm of 0.ltoreq.K.sub.1<0.1 and a
refractive index n.sub.1 at a wavelength of 550 nm of
2.0.ltoreq.n.sub.1.ltoreq.2.5; layer (b): a layer having an
extinction coefficient K.sub.2 at a wavelength of from 380 to 780
nm of 0.1.ltoreq.K.sub.2.ltoreq.2.4 and a refractive index n.sub.2
at a wavelength of from 380 to 780 nm of
0.5.ltoreq.n.sub.2.ltoreq.2.5, and K.sub.2p<K.sub.2q and
n.sub.2p>n.sub.2q being satisfied, where the extinction
coefficients K.sub.2 at wavelengths of p and q which satisfy 380
nm.ltoreq.p<q.ltoreq.780 nm are K.sub.2p and K.sub.2q,
respectively, and the refractive indices n.sub.2 at wavelengths of
p and q are n.sub.2p and n.sub.2q, respectively.
2. The low reflection glass according to claim 1, wherein the
outermost layer is a layer containing SiO.sub.2 as the main
component.
3. The low reflection glass according to claim 1, wherein the
outermost layer has a refractive index of at least 1.45 and less
than 1.5 at a wavelength of 550 nm.
4. The low reflection glass according to claim 1, wherein the
antireflection film is a film having the layer (b) and the
outermost layer disposed in this order from the glass substrate
side.
5. The low reflection glass according to claim 2, wherein the
antireflection film is a film having the layer (b) and the
outermost layer disposed in this order from the glass substrate
side.
6. The low reflection glass according to claim 3, wherein the
antireflection film is a film having the layer (b) and the
outermost layer disposed in this order from the glass substrate
side.
7. The low reflection glass according to claim 4, wherein the layer
(b) contains Ti atoms and N atoms as the main components, the
proportion of Ti atoms and N atoms being TiN.sub.x (x=0.5 to
1.0).
8. The low reflection glass according to claim 5, wherein the layer
(b) contains Ti atoms and N atoms as the main components, the
proportion of Ti atoms and N atoms being TiN.sub.x (x=0.5 to
1.0).
9. The low reflection glass according to claim 6, wherein the layer
(b) contains Ti atoms and N atoms as the main components, the
proportion of Ti atoms and N atoms being TiN.sub.x (x=0.5 to
1.0).
10. A protective plate for a display, comprising the low reflection
glass as defined in claim 1.
11. A protective plate for a display, comprising the low reflection
glass as defined in claim 4.
12. A protective plate for a plasma display, comprising a support
substrate comprising the low reflection glass as defined in claim
1, and a conductive film provided on a side on which no
antireflection film is formed of the support substrate.
13. A protective plate for a plasma display, comprising a support
substrate comprising the low reflection glass as defined in claim
4, and a conductive film provided on a side on which no
antireflection film is formed of the support substrate.
14. The low reflection glass according to claim 1, wherein the
antireflection film further comprises at least one middle
reflective layer disposed between the glass substrate side and the
interlayer.
15. A low reflection glass comprising a glass substrate and an
antireflection film formed on the surface of the glass substrate,
wherein the antireflection film comprises at least two interlayers
and an outermost layer disposed in this order from the glass
substrate side; and the outermost layer is a layer containing Si
atoms, C atoms and O atoms, the content of C atoms being from 0.5
to 3 mol % based on 100 mol % of the total amount of Si atoms, C
atoms and O atoms, and the at least two interlayers can be the same
or different and are selected form the group consisting of the
following layer (a) and layer (b): layer (a): a layer having an
extinction coefficient K.sub.1 at a wavelength of from 380 to 780
nm of 0.ltoreq.K.sub.1<0.1 and a refractive index n.sub.1 at a
wavelength of 550 nm of 2.0.ltoreq.n.sub.1.ltoreq.2.5; layer (b): a
layer having an extinction coefficient K.sub.2 at a wavelength of
from 380 to 780 nm of 0.1.ltoreq.K.sub.2.ltoreq.2.4 and a
refractive index n.sub.2 at a wavelength of from 380 to 780 nm of
0.5.ltoreq.n.sub.2.ltoreq.2.5, and K.sub.2p<K.sub.2q and
n.sub.2p>n.sub.2q being satisfied, where the extinction
coefficients K.sub.2 at wavelengths of p and q which satisfy 380
nm.ltoreq.p<q.ltoreq.780 nm are K.sub.2p and K.sub.2q,
respectively, and the refractive indices n.sub.2 at wavelengths of
p and q are n.sub.2p and n.sub.2q, respectively.
16. The low reflection glass according to claim 15, wherein the
antireflection film further comprises at least one middle
reflective layer disposed between the glass substrate side and the
at least two interlayers.
17. The low reflection glass according to claim 15, wherein the
antireflection film further comprises at least one middle
reflective layer disposed between the at least two interlayers.
18. The low reflection glass according to claim 15, wherein the
antireflection film comprises at least two different
interlayers.
19. The low reflection glass according to claim 15, wherein the
antireflection film comprises at least two layers (b).
20. A protective plate for a display, comprising the low reflection
glass as defined in claim 15.
21. A protective plate for a plasma display, comprising a support
substrate comprising the low reflection glass as defined in claim
15, and a conductive film provided on a side on which no
antireflection film is formed of the support substrate.
Description
TECHNICAL FIELD
[0001] The present invention relates to a low reflection glass and
a protective plate for a display.
BACKGROUND ART
[0002] A low reflection glass on the surface of which reflection of
light is suppressed, is used as a protective plate for a display, a
cover glass for a solar battery, glass for an automobile, glass for
a railway vehicle, glass for shipping, glass for a building
material, etc.
[0003] As such a low reflection glass, for example, the following
has been proposed.
[0004] (1) A low reflection glass having a resin antireflection
film bonded to the surface of a glass substrate (Patent Document
1).
[0005] (2) A low reflection glass having an antireflection film
formed by a sputtering method on the surface of a glass substrate
(Patent Documents 2 to 5).
[0006] However, the low reflection glass (1) has the following
problems.
[0007] (i) As the antireflection film is a resin film, the surface
abrasion resistance is low.
[0008] (ii) As the antireflection film is a resin film, the weather
resistance is low.
[0009] (iii) As the antireflection film should be bonded, the
productivity is low.
[0010] (iv) As the bonded antireflection film is made of a resin,
flatness of the resin surface is limited, thus leading to poor
outer appearance.
[0011] With respect to the low reflection glass (2), the problems
(i) to (iv) of the low reflection glass (1) are solved to a certain
extent, but the surface abrasion resistance and the productivity
are still insufficient.
[0012] Further, Patent Document 5 discloses application of
SiC.sub.xO.sub.y (wherein x is from 0.1 to 3 and y is from 0.1 to
3) as a material of a low refractive index film. However, it failed
to disclose use of the low refractive index film as an outermost
layer. If the low refractive index film is not the outermost layer,
the antireflection performance tends to be decreased. [0013] Patent
Document 1: JP-A-09-314757 [0014] Patent Document 2: JP-A-09-156964
[0015] Patent Document 3: JP-A-10-087348 [0016] Patent Document 4:
JP-A-2003-215304 [0017] Patent Document 5: JP-A-2003-121605
DISCLOSURE OF THE INVENTION
Object to be Accomplished by the Invention
[0018] The present invention provides a low reflection glass
excellent in the abrasion resistance, the weather resistance, the
productivity and the outer appearance and a protective plate for a
display.
Means to Accomplish the Object
[0019] The low reflection glass of the present invention is a low
reflection glass comprising a glass substrate and an antireflection
film formed on the surface of the glass substrate,
[0020] wherein the antireflection film comprises an interlayer and
an outermost layer disposed in this order from the glass substrate
side; and
[0021] the outermost layer is a layer containing Si atoms, C atoms
and O atoms, the content of C atoms being from 0.5 to 3 mol % based
on 100 mol % of the total amount of Si atoms, C atoms and O atoms,
and the interlayer is the following layer (a) or layer (b):
[0022] layer (a): a layer having an extinction coefficient K.sub.1
at a wavelength of from 380 to 780 nm of 0.ltoreq.K.sub.1<0.1
and a refractive index n.sub.1 at a wavelength of 550 nm of
2.0.ltoreq.n.sub.1.ltoreq.2.5;
[0023] layer (b): a layer having an extinction coefficient K.sub.2
at a wavelength of from 380 to 780 nm of
0.1.ltoreq.K.sub.2.ltoreq.2.4 and a refractive index n.sub.2 at a
wavelength of from 380 to 780 nm of 0.5.ltoreq.n.sub.2.ltoreq.2.5,
and K.sub.2p<K.sub.2q and n.sub.2p>n.sub.2q being satisfied,
where the extinction coefficients K.sub.2 at wavelengths of p and q
which satisfy 380 nm.ltoreq.p<q<780 nm are K.sub.2p and
K.sub.2q, respectively, and the refractive indices n.sub.2 at
wavelengths of p and q are n.sub.2p and n.sub.2q, respectively.
[0024] The protective plate for a display of the present invention
comprises the low reflection glass of the present invention.
[0025] The protective plate for a plasma display of the present
invention comprises a support substrate comprising the low
reflection glass of the present invention, and a conductive film
provided on a side on which no antireflection film is formed of the
support substrate.
Effects of the Invention
[0026] According to the present invention, a low reflection glass
excellent in the abrasion resistance, the weather resistance, the
productivity and the outer appearance is obtained, which can be
utilized for a protective plate for a display, etc.
BRIEF DESCRIPTION OF THE DRAWINGS
[0027] FIG. 1 is a cross-sectional view illustrating one example of
a low reflection glass of the present invention.
[0028] FIG. 2 is a cross-sectional view illustrating a preferred
embodiment of a low reflection glass of the present invention.
[0029] FIG. 3 is a cross-sectional view illustrating another
preferred embodiment of a low reflection glass of the present
invention.
[0030] FIG. 4 is a cross-sectional view illustrating another
preferred embodiment of a low reflection glass of the present
invention.
[0031] FIG. 5 is a cross-sectional view illustrating another
preferred embodiment of a low reflection glass of the present
invention.
[0032] FIG. 6 is a cross-sectional view illustrating a first
embodiment of a protective plate for a plasma display of the
present invention.
[0033] FIG. 7 is a cross-sectional view illustrating a second
embodiment of a protective plate for a plasma display of the
present invention.
[0034] FIG. 8 is a cross-sectional view illustrating a third
embodiment of a protective plate for a plasma display of the
present invention.
[0035] FIG. 9 is a cross-sectional view illustrating a fourth
embodiment of a protective plate for a plasma display of the
present invention.
[0036] FIG. 10 is a cross-sectional view illustrating a fifth
embodiment of a protective plate for a plasma display of the
present invention.
[0037] FIG. 11 is a cross-sectional view illustrating a sixth
embodiment of a protective plate for a plasma display of the
present invention.
[0038] FIG. 12 illustrates spectral curves of one side reflectances
on a side on which an antireflection film is formed of low
reflection glasses in Example 1 and Comparative Examples 1 and
2.
[0039] FIG. 13 illustrates spectral curves of one side reflectances
on a side on which an antireflection film is formed of low
reflection glasses in Example 2 and Comparative Examples 3 and
4.
[0040] FIG. 14 illustrates spectral curves of one side reflectances
on a side on which an antireflection film is formed of low
reflection glasses in Examples 3 and 4 and Comparative Examples 5
and 6.
[0041] FIG. 15 is a powder X-ray diffraction pattern of a
sputtering target obtained in Example 15.
BEST MODE FOR CARRYING OUT THE INVENTION
<Low Reflection Glass>
[0042] FIG. 1 is a cross-sectional view illustrating one example of
a low reflection glass of the present invention. A low reflection
glass 10 comprises a glass substrate 12 and an antireflection film
14 formed on the surface of the glass substrate 12.
(Glass Substrate)
[0043] As a material of the glass substrate 12, soda lime silica
glass, borosilicate glass, aluminosilicate glass may, for example,
be mentioned. Further, the glass substrate 12 may be a tempered
glass substrate such as an air-cooled tempered glass or chemically
tempered glass or may be a raw glass substrate not tempered.
[0044] The thickness of the glass substrate 12 is preferably from
0.1 to 15 mm, more preferably from 1.0 to 5.0 mm, particularly
preferably from 2.5 to 3.5 mm. The thickness of the glass substrate
is preferably at least 0.1 mm, more preferably at least 1.0 mm,
whereby the glass substrate has practical rigidity. Further, it is
preferably at most 15 mm, more preferably at most 5.0 mm, whereby
the glass substrate has practical lightness.
(Antireflection Film)
[0045] The antireflection film 14 comprises an interlayer 16 and an
outermost layer 18 in this order from the glass substrate 12
side.
[0046] The outermost layer 18 is a layer located farthest from the
glass substrate and is a layer located on the outermost side.
Further, the outermost layer 18 is a layer containing Si atoms, C
atoms and O atoms. Specifically, it is preferably a layer
containing SiO.sub.2 as the main component and containing C atoms.
The outermost layer 18 may contain other elements other than Si
atoms, C atoms and O atoms within a range not to impair the optical
properties.
[0047] The content of C atoms is from 0.5 to 3.0 mol %, preferably
from 0.5 to 2.0 mol %, more preferably from 1.0 to 1.8 mol % based
on 100 mol % of the total amount of Si atoms, C atoms and O atoms.
When the concentration of C atoms is at least 0.5 mol %, a low
reflection glass excellent in the abrasion resistance and excellent
in the outer appearance with few defects can be obtained. Further,
an excellent productivity is also achieved since the film
deposition rate can be made high. When the content of C atoms is at
most 3 mol %, the refractive index will be less than 1.5, whereby
excellent antireflection effect and excellent abrasion resistance
will be obtained. It is not clearly understood how the C atoms are
contained in the outermost layer 18, however, it is considered that
the C atoms are contained in a state where they are chemically
bonded to Si atoms or O atoms or in a state where the C atoms are
present by themselves in gaps between SiO.sub.2 lattices.
[0048] The outermost layer 18 of the antireflection film 14
preferably contains SiO.sub.2 as the main component. Further,
SiO.sub.2 in the outermost layer 18 in the present invention may
contain a structure deficient in some of O atoms in SiO.sub.2. The
content of Si atoms and O atoms in the outermost layer 18 in the
present invention is preferably from 97.0 to 99.5 mol %, more
preferably from 98.0 to 99.5 mol %, furthermore preferably from
98.2 to 99.0 mol % as calculated as SiO.sub.2 without deficiency of
O atoms. When the SiO.sub.2 content is at least 97.0 mol %, the
refractive index will be less than 1.5, whereby excellent
antireflection effect will be obtained. When the SiO.sub.2 content
is at most 99.5 mol %, the abrasion resistance and the productivity
will be improved.
[0049] The C atom content in the outermost layer 18 is measured by
the following method.
[0050] First, measurement is carried out by using a quadrupole type
secondary ion mass spectrometer (SIMS). Specifically, the SIMS
depth profile of the concentration of each of Si atoms, C atoms and
O atoms relative to the depth of the outermost layer 18, components
of the layer adjacent to the outermost layer and components of the
substrate is prepared, and the average (I.sub.i) of the ion
intensity of C atoms from a depth of 4 nm to the depth at which the
profile of the components of the layer adjacent to the outermost
layer appears in the SIMS depth profile, is calculated. As the
primary ion species, Cs.sup.+ (cesium cation) is employed.
[0051] Further, the content of C atoms is calculated from the
following formula (1):
C atom content=(I.sub.i/I.sub.ref).times.RSF (1)
[0052] In the above formula (1), the intensity of O atoms in a
glass substrate of which the O atom content is known, is regarded
as the reference (I.sub.ref) (normalized by the O atom
intensity).
[0053] Further, with respect to a sample of which the C atom
content is known (content: Z mol %), RSF is calculated by the
following formula (2) from the ion intensity (I.sub.iZ) of C atoms
obtained by SIMS and the intensity (I.sub.ref) of O atoms in the
glass substrate:
RFS=(Z/I.sub.iZ).times.I.sub.ref (2)
[0054] First, a sample is subjected to measurement by usual
negative detection, and with respect to a sample of which the
obtained C atom content is at most 1 mol %, the content is regarded
as the C atom content.
[0055] In the above negative detection, in a case where the C atom
content exceeds 1%, reliability of the obtained data is low.
Accordingly, with respect to a sample of which the content exceeds
1 mol % and is at most 5 mol %, the ion intensity of C atoms is
measured by the same method as the above measurement employing SIMS
except that positive detection is employed, to calculate the C atom
content.
[0056] In the measurement by the above positive detection employing
SIMS, in a case where the C atom content exceeds 5 mol %, the
reliability of the obtained data is low, and accordingly with
respect to a sample of which the content exceeds 5 mol %, the C
atom content is measured by X-ray photoelectron spectroscopy
(XPS).
[0057] The outermost layer 18 preferably has a refractive index at
a wavelength of 550 nm of at least 1.45 and less than 1.5. When the
refractive index of the outermost layer 18 is at least 1.45, in a
case where SiO.sub.2 is contained as the main component, a dense
SiO.sub.2 film not having a porous structure can be obtained,
whereby sufficient strength will be obtained. When the refractive
index of the outermost layer 18 is less than 1.5, an excellent
antireflection effect will be obtained.
[0058] The refractive index of the outermost layer 18 in the
present invention is measured by using a spectral ellipsometer
(manufactured by J.A. Woollam Co., Inc., apparatus name: VASE) at
an incident angle of 70.degree..
[0059] The physical film thickness (hereinafter referred to simply
as the film thickness) of the outermost layer 18 in the present
invention is preferably from 70 to 140 nm, more preferably from 80
to 135 nm. When the film thickness of the outermost layer 18 is
within this range, it is possible to weaken the reflected light by
interference at a wavelength of from 380 nm to 780 nm in the
visible region.
[0060] Further, since the reflected light is weakened by
interference as described above by the antireflection film in the
present invention, the preferred film thickness of the outermost
layer 18 varies depending on the material of the interlayer 16. In
a case where the interlayer 16 is the layer (a), the outermost
layer 18 is preferably from 100 to 135 nm, more preferably from 110
to 130 nm. Further, in a case where the interlayer 16 is the layer
(b), the outermost layer 18 is preferably from 70 to 100 nm, more
preferably from 75 to 95 nm.
[0061] The film thickness of the outermost layer 18 is measured by
using a spectral ellipsometer (manufactured by J.A. Woollam Co.,
Inc., apparatus name: VASE) at an incident angle of 70.degree..
[0062] In the low reflection glass 10 of the present invention, the
antireflection effect will be obtained by combining the outermost
layer 18 and the interlayer 16.
[0063] The interlayer 16 in the present invention is the following
layer (a) or layer (b). The interlayer 16 is formed so as to be
located between the glass substrate and the outermost layer.
[0064] layer (a): a layer having an extinction coefficient K.sub.1
at a wavelength of from 380 to 780 nm of 0.ltoreq.K.sub.1<0.1
and a refractive index n.sub.1 at a wavelength of 550 nm of
2.0.ltoreq.n.sub.1.ltoreq.2.5;
[0065] layer (b): a layer having an extinction coefficient K.sub.2
at a wavelength of from 380 to 780 nm of
0.1.ltoreq.K.sub.2.ltoreq.2.4 and a refractive index n.sub.2 at a
wavelength of from 380 to 780 nm of 0.5.ltoreq.n.ltoreq.2.5, and
K.sub.2p<K.sub.2q and n.sub.2p>n.sub.2q being satisfied,
where the extinction coefficients K.sub.2 at wavelengths of p and q
which satisfy 380 nm.ltoreq.p<q.ltoreq.780 nm are K.sub.2p and
K.sub.2q, respectively, and the refractive indices n.sub.2 at
wavelengths of p and q are n.sub.2p and n.sub.2q, respectively.
[0066] The refractive index of the layer (a) at a wavelength of 550
nm is more preferably from 2.2 to 2.5, furthermore preferably from
2.3 to 2.5. That is, the layer (a) is a high refractive index layer
having a high refractive index material.
[0067] Further, the extinction coefficient K.sub.1 of the layer (a)
at a wavelength of from 380 to 780 nm is more preferably from 0 to
0.05.
[0068] The refractive index and the extinction coefficient of the
interlayer 16 in the present invention are measured by using a
spectral ellipsometer (manufactured by J.A. Woollam Co., Inc.,
apparatus name: VASE) at an incident angle of 70.degree..
[0069] In a case where the interlayer 16 in the present invention
is the layer (a), by the extinction coefficient K.sub.1 being
within the above range, there is substantially no absorption of the
visible light in the layer (a), whereby the transmittance of the
low reflection glass of the present invention can be made high.
Further, by the refractive index n.sub.1 being at least 2.0, the
reflectance of the low reflection glass of the present invention
can be made low. As the reason, since the outermost layer 18 in the
low reflection glass in the present invention is a layer containing
Si atoms and O atoms, it is a low refractive index layer. Further,
by applying, as the interlayer disposed on the substrate side from
the outermost layer 18, the layer (a) having a refractive index of
at least 2.0, reflected light can be weakened by the interference
of light, whereby the reflectance of the low reflective glass of
the present invention can be made low. Further, the reflectance of
the low reflection glass in the present invention means the
luminous reflectance on one side on which the antireflection film
14 is formed against light at a wavelength of from 480 to 780 nm.
Further, the upper limit of the refractive index of the layer (a)
is regarded as 2.5 since there is no practical material having a
refractive index exceeding 2.5 at present.
[0070] The luminous reflectance in the present invention is a
reflectance obtained by measuring the spectral reflectance in
accordance with JIS R3106 1999 and calculating the weighted average
by the weighting coefficient in appendix 1, and is preferably from
0.1 to 3%, more preferably from 0.1 to 1%.
[0071] A material to be used for the layer (a) may, for example, be
a material (hereinafter referred to as TiO.sub.y) containing Ti
atoms and O atoms as the main components, the proportion of Ti
atoms and O atoms being TiO.sub.y (y=1.9 to 2.0) (extinction
coefficient: at least 0 and less than 0.1, refractive index: 2.2 to
2.5);
[0072] a material (hereinafter referred to as NbO.sub.z) containing
Nb atoms and O atoms as the main components, the proportion of Nb
atoms and O atoms being NbO.sub.Z (z=1 to 3) (extinction
coefficient: at least 0 and less than 0.1, refractive index:
2.25);
[0073] a material (hereinafter referred to as SiN.sub.t) containing
Si atoms and N atoms as the main components, the proportion of Si
atoms and N atoms being SiN.sub.t (t=1.2 to 1.4) (extinction
coefficient: at least 0 and less than 0.1, refractive index: 2.0 to
2.2);
[0074] a material (hereinafter referred to as TaO.sub.u) containing
Ta atoms and O atoms as the main components, the proportion of Ta
atoms and O atoms being TaO.sub.u (U=1 to 3) (extinction
coefficient: at least 0 and less than 0.1, refractive index: 2 to
2.3); or
[0075] a material (hereinafter referred to as ZrO.sub.v) containing
Zr atoms and O atoms as the main components, the proportion of Zr
atoms and O atoms being ZrO.sub.v (v=1.9 to 2.0) (extinction
coefficient: at least 0 and less than 0.1, refractive index: 2 to
2.3).
[0076] Further, the main component means that the amount of the
corresponding element (for example, in the case of TiO.sub.y, the
total number of moles of Ti atoms and O atoms) based on the number
of moles of all the atoms in the layer (a) is at least 90 mol %,
more preferably at least 95 mol %, furthermore preferably at least
98 mol %, most preferably at least 99 mol %.
[0077] The material of the layer (a) in the present invention is
preferably TiO.sub.y or NbO.sub.z, more preferably TiO.sub.y, in
view of high refractive index, thus making the reflectance of the
low reflection glass of the present invention sufficiently low.
[0078] The layer (b) in the present invention is a layer having an
extinction coefficient K.sub.2 at a wavelength of from 380 to 780
nm of 0.1.ltoreq.K.sub.2.ltoreq.2.4 and a refractive index n.sub.2
at a wavelength of from 380 to 780 nm of
0.5.ltoreq.n.sub.2.ltoreq.2.5, and K.sub.2p<K.sub.2q and
n.sub.2p>n.sub.2q being satisfied, where the extinction
coefficients K.sub.2 at wavelengths of p and q which satisfy 380
nm.ltoreq.p<q.ltoreq.780 nm are K.sub.2p and K.sub.2q,
respectively, and the refractive indices n.sub.2 at wavelengths of
p and q are n.sub.2p and n.sub.2q, respectively. That is, the layer
(b) is a light absorbing layer having a light absorbing
material.
[0079] In a case where the interlayer 16 in the present invention
is the layer (b), by the extinction coefficient K.sub.2 and the
refractive index n.sub.2 being within the above ranges and
satisfying the above relations, the reflectance of the low
reflection glass of the present invention can be made low. This is
because by combining the outermost layer 18 containing Si atoms and
O atoms and the layer (b) having the above extinction coefficient
and refractive index, the reflected light can be weakened by
interference of light, whereby the reflectance of the low
reflection glass of the present invention can be made low. Further,
since the layer (b) has properties to absorb visible light, it can
absorb a larger quantity of reflected light, and as a result, the
reflectance against the external light can be made lower.
Accordingly, when the low reflection glass of the present invention
is used as a protective plate for a display, high visibility for an
image can be obtained.
[0080] A material which satisfies the above extension coefficient
K.sub.2 and refractive index n.sub.2 to be used for the layer (b)
in the present invention is preferably a material containing Ti
atoms and N atoms as the main components, the proportion of Ti
atoms and N atoms being TiN.sub.x (X=0.5 to 1.0) (extinction
coefficient: 0.9 to 2.2, refractive index: 1.5 to 2.5). TiN.sub.x
is preferred as the material of the layer (b) since the extinction
coefficient and the refractive index of TiN.sub.x are optimum in a
case of forming a film having antireflection performance in
combination with SiO.sub.2 of the outermost layer 18.
[0081] Further, the main component means that the amount of the
corresponding element (for example, in the case of TiN.sub.x, the
number of moles of Ti atoms and N atoms) based on the number of
moles of all the atoms in the layer (b) is at least 90 mol %, more
preferably at least 95 mol %, furthermore preferably at least 98
mol %, most preferably at least 99 mol %. The layer (b) may further
contain O atoms in addition to Ti atoms and N atoms.
[0082] The film thickness of the interlayer 16 varies depending on
the material of the interlayer 16 and the entire structure of the
antireflection film.
[0083] For example, the film thickness of the layer (a) is
preferably from 10 to 65 nm, more preferably from 10 to 30 nm,
furthermore preferably from 10 to 20 nm. When the film thickness of
the layer (a) is within this range, the low reflection glass of the
present invention can weaken reflected light by interference at a
wavelength of from 380 nm to 780 nm in the visible region. Within
the more preferred range, or within the furthermore preferred
range, the layer of a high refractive index material which usually
has a low film deposition rate can be made thin, whereby the time
required for film deposition of the entire antireflection film of
the present invention can be shortened and as a result, the low
reflection glass of the present invention can be produced with high
productivity.
[0084] Further, the film thickness of the layer (b) is preferably
from 5 to 25 nm, more preferably from 5 to 12 nm, furthermore
preferably from 7 to 12 nm. When the film thickness of the layer
(b) is within this range, the low reflection glass of the present
invention can weaken the reflected light by interference at a
wavelength of from 380 to 780 nm in the visible region.
[0085] The low reflection glass of the present invention has an
excellent antireflection effect by applying the layer (a) as a high
refractive index layer or the layer (b) as a light absorbing layer
as the interlayer 16 in combination with the outermost layer 18
having a low refractive index. Further, by using, as the material
of the outermost layer 18, a material containing Si atoms, O atoms
and C atoms and containing the C atoms in a specific ratio, the
outermost layer 18 can be a layer having a low refractive index and
being hard. As a result, the low reflection glass of the present
invention can achieve both two effects of excellent antireflection
performance and excellent abrasion resistance.
[0086] The low reflection glass of the present invention may
contain other layer as the case requires. Such other layer may, for
example, be a middle refractive index layer: a layer having a
refractive index at a wavelength of 550 nm of at least 1.5 and less
than 2.0, or a low refractive index layer: a layer having a
refractive index at a wavelength of 550 nm of at least 1.45 and
less than 1.5.
[0087] A material having a refractive index of at least 1.5 and
less than 2.0 to be used for the middle refractive index layer may,
for example, be SiO (extinction coefficient: 0 to 0.5, refractive
index: 1.7 to 1.97), AlO.sub.s (s=1 to 2) (extinction coefficient:
0 to 0.1, refractive index: 1.5 to 1.7), Y.sub.2O.sub.3 (extinction
coefficient: 0 to 0.1, refractive index: 1.87 or La.sub.2O.sub.3
(extinction coefficient: 0 to 0.1, refractive index: 1.85).
[0088] A material having a refractive index of at least 1.45 and
less than 1.5 to be used for the low refractive index layer may,
for example, be SiO.sub.2 (refractive index: 1.46) or MgF.sub.2
(refractive index: 1.38).
[0089] The low reflection glass of the present invention may
contain only one interlayer or two or more interlayers. In a case
where it contains two or more interlayers, the respective
interlayers may be layers made of different materials, or all the
layers may be layers made of the same material. Further, the
thicknesses of the respective interlayers may be all the same or
may be different.
[0090] With respect to other layers, the low reflective glass may
contain only one layer or two or more layers.
[0091] Further, the antireflection film of the present invention
may contain e.g. a barrier layer having substantially no optical
function. The barrier layer is a layer to be provided on the
surface of the layer (a) or the layer (b) for the purpose of
preventing the layer (a) or the layer (b) from being damaged even
after a high temperature process such as a tempering step or a
bending step after film deposition. In order that the barrier layer
may have substantially no optical function, the film thickness of
the barrier layer is preferably from 0.1 to 10 nm. A material of
the barrier layer may, for example, be SiN, Ti or Cr.
[0092] FIG. 2 is a cross-sectional view illustrating a preferred
embodiment of a low reflection glass of the present invention. A
low reflection glass 10a comprises a glass substrate 12 and an
antireflection film 14a formed on the surface of the glass
substrate 12, wherein the antireflection film 14a is a film having
a layer (a) 16a and an outermost layer 18 laminated in this order
from the glass substrate 12 side. That is, it is a low reflection
glass 10a having a structure of glass substrate 12/layer (a)
16a/outermost layer 18.
[0093] FIG. 3 is a cross-sectional view illustrating another
preferred embodiment of a low reflection glass of the present
invention. A low reflection glass 10b comprises a glass substrate
12 and an antireflection film 14b formed on the surface of the
glass substrate 12, wherein the antireflection film 14b is a film
having a layer (b) 16b and an outermost layer 18 laminated in this
order from the glass substrate 12 side. That is, it is a low
reflection glass 10b having a structure of glass substrate 12/layer
(b) 16b/outermost layer 18.
[0094] FIG. 4 is a cross-sectional view illustrating another
preferred embodiment of a low reflection glass of the present
invention. A low reflection glass 10c comprises a glass substrate
12 and an antireflection film 14c formed on the surface of the
glass substrate 12, wherein the antireflection film 14c is a film
having a middle refractive index layer 17, a layer (a) 16a and an
outermost layer 18 laminated in this order from the glass substrate
12 side. That is, it is a low reflection glass 10c having a
structure of glass substrate 12/middle refractive index layer
17/layer (a) 16a/outermost layer 18.
[0095] FIG. 5 is a cross-sectional view illustrating another
preferred embodiment of a low reflection glass of the present
invention. The low reflection glass 10d comprises a glass substrate
12 and an antireflection film 14d formed on the surface of the
glass substrate 12, wherein the antireflection film 14d is a film
having layers (a) 16a and low refractive index layers 19
alternately laminated (2m+1) times (wherein m is an integer of at
least 1) in this order from the glass substrate 12 side and having
an outermost layer 18 on the surface of the layer (a) 16a farthest
from the glass substrate 12. That is, it is a low reflection glass
10d having a structure of glass substrate 12/[layer (a) 16a/low
refractive index layer 19].sub.m/layer (a) 16a/outermost layer
18.
[0096] In this case, the value of m is preferably 1 or 2 from the
viewpoint of productivity and economical efficiency, in a case
where the low reflection glass of the present invention is used for
a protective plate for a display.
[0097] The combination of the material, the film thickness, etc. of
the antireflection film 14 is not particularly limited so long as
the luminous reflectance on one side on which the antireflection
film 14 is formed of the low reflection glass 10 of the present
invention is lower than the reflectance on the surface of the glass
substrate 12. The luminous reflectance on one side on which the
antireflection film 14 is formed of the low refractive index glass
10 of the present invention is preferably from 0 to 2.0%, more
preferably from 0.1 to 1.5%, furthermore preferably from 0.5 to
0.9% on average against light at a wavelength of from 480 to 780
nm.
(Process for Producing Low Reflection Glass)
[0098] The low reflection glass 10 is produced by forming the
interlayer 16 on the glass substrate 12 and then forming the
outermost layer 18. As the case requires, other layer or the
barrier layer is formed before or after the interlayer 16 is
formed.
[0099] As a method of forming the interlayer 16 and the outermost
layer 18, a-sputtering method, a vacuum deposition method, an ion
plating method, a chemical vapor deposition method may, for
example, be mentioned, and a sputtering method is preferred in view
of favorable stability in quality and properties, and in view of
uniform formation of the interlayer 16 and the outermost layer 18
on a large area glass substrate surface with good productivity.
[0100] As the sputtering method, a DC sputtering method, a pulse
sputtering method or an AC sputtering method may, for example, be
mentioned.
[0101] In a case where the interlayer 16 is the layer (a)
(TiO.sub.y), formation of the interlayer 16 by the sputtering
method is carried out, for example, as follows.
[0102] While a mixed gas of Ar and O.sub.2 is introduced into a
chamber of a sputtering apparatus, DC magnetron sputtering is
carried out by using a Ti metal target to form the layer (a) on the
glass substrate 12.
[0103] In a case where the interlayer 16 is the layer (b)
(TiN.sub.x), formation of the interlayer 16 by the sputtering
method is carried out, for example, as follows.
[0104] While a mixed gas of Ar and N.sub.2 is introduced into a
chamber of a sputtering apparatus, DC magnetron sputtering is
carried out by using a Ti metal target to form the layer (b) on the
glass substrate 12.
[0105] Formation of the outermost layer 18 by the sputtering method
is carried out, for example, as follows.
[0106] While a gas containing CO.sub.2 is introduced into a chamber
of a sputtering apparatus, AC magnetron sputtering is carried out
by using a target containing Si as the main component to form the
outermost layer 18 on the interlayer 16. As the gas containing
CO.sub.2, a gas of CO.sub.2 alone or a mixed gas of Ar and CO.sub.2
may, for example, be mentioned.
[0107] It is preferred to carry out formation of the outermost
layer 18 in the present invention by the sputtering method by using
a gas containing CO.sub.2, whereby the film deposition rate is
high, thus leading to an excellent productivity.
[0108] The optimum flow ratio (Ar/CO.sub.2) of the Ar gas to the
CO.sub.2 gas in the mixed gas varies depending on the power density
at the time of sputtering. At a practical power density, the flow
ratio (volume ratio) (Ar/CO.sub.2) is preferably
(0/10)<(Ar/CO.sub.2).ltoreq.(3/7), more preferably
(1/9).ltoreq.(Ar/CO.sub.2).ltoreq.(3/7), furthermore preferably
(2/8).ltoreq.(Ar/CO.sub.2).ltoreq.(3/7). When the value of
(Ar/CO.sub.2) is within this range, the content of C atoms in the
film will be proper.
[0109] Further, in the mixed gas of Ar and CO.sub.2, the lower the
ratio of CO.sub.2, the higher the content of C atoms in the film
tends to be.
[0110] Further, formation of the outermost layer 18 by the
sputtering method may also be carried out as follows.
[0111] While an Ar gas is introduced into a chamber of a sputtering
apparatus, AC magnetron sputtering is carried out by using a SiC
target to form the outermost layer 18 on the interlayer 16.
[0112] In a case where the outermost layer 18 in the present
invention is formed by the sputtering method, in a state where the
outermost layer 18 after film deposition is exposed to the air, the
abrasion resistance of the outermost layer 18 tends to increase
with time. The reason is not necessarily clear, but is considered
that a very small amount of impurities in the air are attached to
the surface of the outermost layer 18, whereby the sliding
properties are improved, thus improving the abrasion resistance.
However, this has substantially no influence over the transmittance
or reflection properties of visible light which are optical
properties. That is, the above optical properties are substantially
not changed with time after film deposition.
[0113] In a case where the low reflection glass 10 of the present
invention is applied to a protective plate for a display for
example, immediately after the outermost layer 18 is formed by the
sputtering method, the outermost layer 18 is kept in a state where
it is substantially shut out from the air in some cases. The state
where it is shut out from the air may, for example, be a state
where a plurality of low reflection glasses 10 are overlaid by
means of microfine beads. In a state where it is substantially shut
out from the air, the abrasion resistance of the outermost layer 18
will not substantially be improved with time after film deposition.
When the low reflection glass 10 as shut out from the air is
treated in the next step, the outermost layer 18 in substantially
the same state as immediately after the film deposition is
subjected to the next step. Accordingly, in order to prevent the
outermost layer 18 from being damaged by treatment in the next
step, an excellent abrasion resistance immediately after film
deposition is important. Further, in a case where the low
reflection glass 10 of the present invention is used as a
protective plate for a display, after the low reflection glass 10
is assembled into a display, it is always exposed to the air, and
accordingly a high abrasion resistance after time passes after the
film deposition is also important.
[0114] In the above-described low reflection glass 10, the
outermost layer 18 is a layer containing Si atoms, C atoms and O
atoms, and the content of C atoms is from 0.5 to 3 mol % based on
100 mol % of the total amount of Si atoms, C atoms and O atoms, and
accordingly the low reflection glass 10 is excellent in the
antireflection effect, excellent in the surface abrasion resistance
and excellent in the productivity.
[0115] Further, the above-described low reflection glass 10 of the
present invention is excellent in the weather resistance, the
productivity and the outer appearance as compared with a
conventional low reflection glass having an antireflection film
bonded.
<Protective Plate for Display>
[0116] The protective plate for a display of the present invention
comprises a low reflection glass of the present invention. Further,
depending on the type of the display to which the protective plate
is attached, the display may further have a film having other
function required therefor.
<Protective Plate for Plasma Display>
[0117] The protective plate for a plasma display (hereinafter
referred to as a protective plate) of the present invention
comprises a support substrate comprising the low reflection glass
of the present invention and a conductive film provided on a side
on which no antireflection film is formed of the support substrate.
The conductive film may be directly formed on the surface of the
support substrate, or an electroconductive film having the
conductive film laminated on the surface of a resin film may be
bonded on the surface of the support substrate. The protective
plate of the present invention may further have a film having near
infrared shielding function, a film having a color tone correcting
function, or the like.
First Embodiment
[0118] In FIG. 6 is shown a protective plate according to a first
embodiment. A protective plate 20 comprises a low reflection glass
10 (support substrate), an electroconductive film 24 bonded to the
surface of the glass substrate 12 of the low reflection glass 10 by
means of a colored adhesive layer 22, and a protective resin layer
26 formed on the surface of the electroconductive film 24.
[0119] The colored adhesive layer 22 is a layer comprising an
adhesive having all of near infrared shielding function, color tone
correcting function and ultraviolet shielding function.
[0120] The adhesive may be a commercially available adhesive. It
may, for example, be an adhesive of an acrylate copolymer,
polyvinyl chloride, epoxy resin, polyurethane, vinyl acetate
copolymer, styrene/acrylic copolymer, polyester, polyamide,
polyolefin, styrene/butadiene copolymer rubber, butyl rubber or
silicone resin. In the adhesive, a near infrared absorber, a
coloring agent and an ultraviolet absorber are incorporated.
[0121] The electroconductive film 24 comprises a resin film 28 and
an electroconductive mesh layer 30 made of copper formed on the
resin film (electroconductive film), and has electromagnetic wave
shielding function. Usually, it is produced by bonding a copper oil
on the resin film 28, followed by processing into a mesh. The resin
film 28 may, for example, be a polyethylene terephthalate
(hereinafter referred to as PET) film.
[0122] The protective resin layer 26 is formed by coating the
surface on the electroconductive mesh layer 30 side of the
electroconductive film 24 with a photocuring resin or a
thermosetting resin in a predetermined thickness, followed by
curing. The resin may, for example, be an acrylic resin, an epoxy
resin, a urethane resin or a polyester resin.
Second Embodiment
[0123] In FIG. 7 is shown a protective plate according to a second
embodiment. A protective plate 32 comprises a low reflection glass
10 (support substrate), an electroconductive film 24 bonded to the
surface of the glass substrate 12 of the low reflection glass 10 by
means of a transparent adhesive layer 34, and a resin film 38
bonded to the surface of the electroconductive film 24 by means of
a colored adhesive layer 36.
[0124] Here, in the second embodiment, the same structure as in the
first embodiment is provided with the same symbol as in FIG. 6 and
its description is omitted.
[0125] The transparent adhesive layer 34 may have an ultraviolet
shielding function. The adhesive may be a commercially available
adhesive, and is preferably an acrylic adhesive, a silicone
adhesive, a butadiene adhesive, a urethane adhesive or the like. In
the adhesive, an ultraviolet absorber may be incorporated.
[0126] The colored adhesive layer 36 is a layer comprising an
adhesive having both near infrared shielding function and color
tone correcting function. In a case where the transparent adhesive
layer 34 has no ultraviolet shielding function, the colored
adhesive layer 36 further has an ultraviolet shielding function.
The adhesive may be a commercially available adhesive, and is
preferably an acrylic adhesive, a silicone adhesive, a butadiene
adhesive, a urethane adhesive or the like. In the adhesive, a near
infrared absorber and a coloring agent are incorporated, and an
ultraviolet absorber may further be incorporated.
[0127] The resin film 38 may, for example, be a PET film.
Third Embodiment
[0128] In FIG. 8 is shown a protective plate according to a third
embodiment.
[0129] A protective plate 40 comprises a low reflection glass 10
(support substrate), an electroconductive film 24 bonded to the
surface of the glass substrate 12 of the low reflection glass 10 by
means of a transparent adhesive layer 34, and a near infrared
shielding film 44 bonded to the surface of the electroconductive
film 24 by means of a colored adhesive layer 42.
[0130] In the third embodiment, the same structure as in the first
or second embodiment is provided with the same symbol as in FIG. 6
or 7, and its description is omitted.
[0131] The colored adhesive layer 42 is a layer comprising an
adhesive having a color tone correcting function. In a case where
the transparent adhesive layer 34 has no ultraviolet shielding
function, the colored adhesive layer 42 further has an ultraviolet
shielding function. The adhesive may, for example, be a
commercially available adhesive, and is preferably an acrylic
adhesive, a silicone adhesive, a butadiene adhesive, a urethane
adhesive or the like. In the adhesive, a coloring agent is
incorporated, and an ultraviolet absorber may further be
incorporated.
[0132] The near infrared shielding film 44 comprises a resin film
48 and a near infrared shielding coating layer 46 formed on the
resin film. The near infrared shielding coating layer 46 is formed
by coating the resin film 48 with a coating agent containing a
resin and a near infrared absorber, followed by drying. The resin
film 48 may, for example, be a PET film.
Fourth Embodiment
[0133] In FIG. 9 is shown a protective plate according to a fourth
embodiment. A protective plate 50 comprises a low reflection glass
10 (support substrate), and an electroconductive film 24 bonded on
the surface of the glass substrate 12 of the low reflection glass
10 by means of a colored adhesive layer 22.
[0134] In the fourth embodiment, the same structure as in the first
embodiment is provided with the same symbol as in FIG. 6, and its
description is omitted.
Fifth Embodiment
[0135] In FIG. 10 is shown a protective plate according to a fifth
embodiment. A protective plate 52 comprises a low reflection glass
10 (support substrate), an electroconductive film 54 bonded to the
surface of the glass substrate 12 of the low reflection glass 10 by
means of a transparent adhesive layer 34, an electrode 60 formed
around the periphery of the electroconductive film 54, and a resin
film 38 bonded to the surface of the electroconductive film 54 by
means of a colored adhesive layer 36.
[0136] In the fifth embodiment, the same structure as in the second
embodiment is provided with the same symbol as in FIG. 7, and its
description is omitted.
[0137] The electroconductive film 54 comprises a resin film 56 and
a conductive film 58 formed on the resin film by the sputtering
method, and has both electromagnetic wave shielding function and
near infrared shielding function. The electroconductive layer 58 is
usually a laminated film alternately having metal oxide layers (an
oxide of In and Sn, an oxide of Ti and Zn, an oxide of Al and Zn,
niobium oxide, or the like) and metal layers (Ag, a Ag alloy, or
the like) with a number of the metal layers of n and a number of
the metal oxide layers of n+1 (wherein n is an integer of at least
1). The resin film 56 may, for example, be a PET film.
[0138] The electrode 60 is formed by applying a silver paste
containing silver, glass frit and a resin or a copper paste
containing copper, glass frit and a resin, followed by firing.
Otherwise, it may be formed by bonding an aluminum tape provided
with an electroconductive adhesive.
Sixth Embodiment
[0139] In FIG. 11 is shown a protective plate according to a sixth
embodiment. A protective plate 62 comprises a low reflection glass
10 (support substrate), an electroconductive film 54 bonded to the
surface of the glass substrate 12 of the low reflection glass 10 by
means of a colored adhesive layer 64, and an electrode 60 bonded
around the periphery of the electroconductive film 54.
[0140] In the sixth embodiment, the same structure as in the fifth
embodiment is provided with the same symbol as in FIG. 10, and its
description is omitted.
[0141] The colored adhesive layer 64 is a layer comprising an
adhesive having both color tone correcting function and ultraviolet
shielding function. The adhesive may be a commercially available
adhesive, and is preferably an acrylic adhesive, a silicone
adhesive, a butadiene adhesive, a urethane adhesive or the like. In
the adhesive, a coloring agent and an ultraviolet absorber are
incorporated.
[0142] The above-described protective plates 20, 32, 40, 50, 52 and
62, are excellent in the abrasion resistance, the weather
resistance, the productivity and the outer appearance, since the
low reflection glass 10 excellent in the abrasion resistance, the
weather resistance, the productivity and the outer appearance is
used as the support substrate.
EXAMPLES
[0143] Now, the present invention will be described in further
detail with reference to Examples, but the present invention is by
no means restricted to such specific Examples.
(Measurement of Content of C Atoms)
[0144] The C atom content in the outermost layer 18 was measured by
the following method.
[0145] Measurement was carried out by using a quadrupole type
secondary ion mass spectrometer (SIMS). Specifically, the SIMS
depth profile of the concentration of each of Si atoms, C atoms and
O atoms relative to the depth of the outermost layer 18, components
of the layer adjacent to the outermost layer and components of the
substrate was prepared. Then, the average (I.sub.i) of the ion
intensity of C atoms from a depth of 4 nm to the depth at which the
profile of the components of the layer adjacent to the outermost
layer appeared in the SIMS depth profile, was calculated. As the
primary ion species, Cs.sup.+ (cesium cation) was employed.
Further, the content of C atoms was calculated from the following
formula (1):
C atom content=(I.sub.i/I.sub.ref).times.RSF (1)
[0146] In the above formula (1), the intensity of O atoms (content:
known) in a glass substrate was regarded as the reference
(I.sub.ref) (normalized by the intensity of O atoms).
[0147] Further, with respect to a sample of which the C atom
content was known (content: Z mol %), RSF was calculated by the
following formula (2) from the ion intensity (I.sub.iZ) of C atoms
obtained by SIMS and the intensity (I.sub.ref) of O atoms in the
glass substrate:
RFS=(Z/I.sub.iZ).times.I.sub.ref (2)
[0148] First a sample was subjected to measurement by negative
detection, and with respect to a sample of which the obtained C
atom content was at most 1 mol %, the content was regarded as the C
atom content. In the measurement by the negative detection, as the
sample of which the C atom content was known, a standard sample
having C atoms ion-implanted in a SiO.sub.2 film was used to
calculate the RSF value.
[0149] In the negative detection employing SIMS, in a case where
the C atom content exceeds 1%, reliability of the obtained data is
low. Accordingly, with respect to a sample of which the content
exceeded 1%, the ion intensity of C atoms was measured by the same
method as the above measurement employing SIMS except that positive
detection was employed, to calculate the C atom content. In the
positive detection, as the sample of which the content of C atoms
was known, a sample having a C atom content of 13.2% as a result of
X-ray photoelectron spectroscopy (XPS) was used to calculate the
RSF value. With respect to a sample of which the C atom content
obtained by the positive detection employing SIMS exceeded 1% and
was at most 5%, the content was regarded as the C atom content.
[0150] In the measurement by the positive detection employing SIMS,
in a case where the C atom content exceeds 5%, the reliability of
the obtained data is low, and accordingly with respect to a sample
of which the content exceeded 5%, the C atom content was measured
by X-ray photoelectron spectroscopy (XPS).
(Evaluation of Abrasion Resistance)
[0151] Using a continuous loading scratching intensity tester
(manufactured by Shinto Scientific Co., Ltd., HEIDON TRIBOGEAR TYPE
18, needle: 0.1 mm), the scratch start load on the surface of the
antireflection film was measured.
[0152] In the evaluation of the abrasion resistance in the present
invention, the scratch start load varies depending on the state of
the needle attached to the continuous loading scratching intensity
tester. Accordingly, evaluation was carried out by using the same
needle and relatively comparing the values of the scratch start
load of samples measured substantially at the same time. In these
Examples, in Examples 1 and 2 and Comparative Examples 1 to 4, the
same needle was used, and the measurement was carried out
substantially at the same time. Further, in Examples 3 and 4 and
Comparative Examples 5 to 7, the same needle was used, and the
measurement was carried out substantially at the same time.
(Measurement of Spectral Curve of Reflectance)
[0153] Using a spectrophotometer (manufactured by Hitachi
High-Technologies Corporation, U4100), the one side reflectance on
a surface on which an antireflection film was formed of the
obtained low reflection glass against light having a wavelength of
from 380 to 780 nm was measured.
Example 1
[0154] An in-line sputtering apparatus comprising two or more
chambers was evacuated of air to 1.times.10.sup.-5 Torr or below, a
mixed gas of Ar and N.sub.2 (Ar/N.sub.2=93/7 flow ratio (volume
ratio, the same applied hereinafter)) was introduced to a first
chamber, a mixed gas of Ar and CO.sub.2 (Ar/CO.sub.2=3/7 flow
ratio) was introduced to a second chamber, and the flow rates of
the respective mixed gases were adjusted so that the pressure in
the respective chambers was 3.times.10.sup.-3 Torr.
[0155] A soda lime silica glass of 1 m.times.0.7 m.times.3.2 mm in
thickness was washed with water, dried and placed in the first
chamber of the sputtering apparatus, and DC magnetron sputtering
was carried out by using a Ti metal target disposed in the first
chamber to form an interlayer comprising TiN.sub.x on the soda lime
silica glass. With respect to the extinction coefficient K.sub.2
and the refractive index n.sub.2 of the formed interlayer
comprising TiN.sub.x, 0.1.ltoreq.K.sub.2.ltoreq.2.4 and
0.5.ltoreq.n.sub.2.ltoreq.2.5 at a wavelength of from 380 to 780
nm, and K.sub.2p<K.sub.2q and n.sub.2p>n.sub.2q were
satisfied, where the extinction coefficients K.sub.2 at wavelengths
of p and q which satisfy 380 nm.ltoreq.p<q.ltoreq.780 nm are
K.sub.2p and K.sub.2q, respectively, and the refractive indices
n.sub.2 at wavelengths of p and q are n.sub.2p and n.sub.2q,
respectively. That is, the interlayer in Example 1 was the layer
(b). Then, the soda lime silica glass was moved to the second
chamber, and AC magnetron sputtering was carried out by using a Si
target disposed in the second chamber to form an outermost layer
which is a layer (hereinafter referred to as a SiCO layer)
containing Si atoms, C atoms and O atoms on the interlayer. This
outermost layer was a layer containing SiO.sub.2 as the main
component.
[0156] The film thicknesses of the respective layers of the
antireflection film, the refractive index of the outermost layer,
the content of C atoms in the outermost layer, and abrasion
resistances 3 to 4 hours, and 4 to 5 days after film deposition of
the antireflection film, are shown in Table 1. Further, the
spectral curve of the one side reflectance on the side on which the
antireflection film was formed of the low reflection glass is shown
in FIG. 12. Further, the luminous reflectance is shown in Table
1.
Example 2
[0157] The same sputtering apparatus as in Example 1 was evacuated
of air to 1.times.10.sup.-5 Torr or below, a mixed gas of Ar and
O.sub.2 (Ar/O.sub.2=2/8: flow ratio) was introduced to the first
chamber, a mixed gas of Ar and CO.sub.2 (Ar/CO.sub.2=3/7: flow
ratio) was introduced to the second chamber, and the flow rates of
the respective mixed gases were adjusted so that the pressure in
the respective chambers was 3.times.10.sup.-3 Torr.
[0158] A soda lime silica glass of 1 m.times.0.7 m.times.3.2 mm in
thickness was washed with water, dried and placed in the first
chamber of the sputtering apparatus, and DC magnetron sputtering
was carried out by using a Ti metal target disposed in the first
chamber to form an interlayer comprising TiO.sub.y on the soda lime
silica glass. Of the formed interlayer (TiO.sub.y), the extinction
coefficient K.sub.1 was 0, and the refractive index n.sub.1 was
2.45. That is, the interlayer in Example 2 was the layer (a). Then,
the soda lime silica glass was moved to the second chamber, and AC
magnetron sputtering was carried out by using a Si target disposed
in the second chamber to form an outermost layer which is a SiCO
layer on the interlayer. The outermost layer was a layer containing
SiO.sub.2 as the main component.
[0159] The film thicknesses of the respective layers in the
antireflection film, the refractive index of the outermost layer,
the content of C atoms in the outermost layer, and the abrasion
resistances 3 to 4 hours and 4 to 5 days after film deposition of
the antireflection film are shown in Table 1. Further, the spectral
curve of the one side reflectance on the side on which the
antireflection film was formed of the low reflection glass is shown
in FIG. 13. Further, the luminous reflectance is shown in Table
1.
Comparative Examples 1 and 2
[0160] An interlayer comprising TiN.sub.x and an outermost layer
comprising SiO.sub.2 containing no C were formed in the same manner
as in Example 1 except that the mixed gas introduced to the second
chamber was changed to a mixed gas of Ar and O.sub.2.
[0161] The film thicknesses of the respective layers in the
antireflection film, the refractive index of the outermost layer,
the content of C atoms in the outermost layer, and the abrasion
resistances 3 to 4 hours and 4 to 5 days after film deposition of
the antireflection film are shown in Table 1. Further, the spectral
curve of the one side reflectance on the side on which the
antireflection film was formed of the low reflection glass is shown
in FIG. 12. Further, the luminous reflectance is shown in Table
1.
Comparative Examples 3 and 4
[0162] An interlayer comprising TiO.sub.y and an outermost layer
comprising SiO.sub.2 containing no C were formed in the same manner
as in Example 2 except that the mixed gas introduced to the second
chamber was changed to a mixed gas of Ar and O.sub.2.
[0163] The film thicknesses of the respective layers in the
antireflection film, the refractive index of the outermost layer,
the content of C atoms in the outermost layer, and the abrasion
resistances 3 to 4 hours and 4 to 5 days after film deposition of
the antireflection film are shown in Table 1. Further, the spectral
curve of the one side reflectance on the side on which the
antireflection film was formed of the low reflection glass is shown
in FIG. 13. Further, the luminous reflectance is shown in Table
1.
Example 3
[0164] An interlayer comprising TiN.sub.x and an outermost layer
which is a SiCO layer were formed in the same manner as in Example
1 except that a mixed gas of Ar and CO.sub.2 (Ar/CO.sub.2=0/10:
flow ratio) was used as the mixed gas introduced to the second
chamber.
[0165] The film thicknesses of the respective layers in the
antireflection film, the refractive index of the outermost layer,
the content of C atoms in the outermost layer, and the abrasion
resistance 4 to 5 days after film deposition of the antireflection
film are shown in Table 1. Further, the spectral curve of the one
side reflectance on the side on which the antireflection film was
formed of the low reflection glass is shown in FIG. 14. Further,
the luminous reflectance is shown in Table 1.
Example 4
[0166] An interlayer comprising TiN.sub.x and an outermost layer
which is a SiCO layer were formed in the same manner as in Example
1 except that a mixed gas of Ar and CO.sub.2 (Ar/CO.sub.2=2/8: flow
ratio) was used as the mixed gas introduced to the second
chamber.
[0167] The film thicknesses of the respective layers in the
antireflection film, the refractive index of the outermost layer,
the content of C atoms in the outermost layer, and the abrasion
resistance 4 to 5 days after film deposition of the antireflection
film are shown in Table 1. Further, the spectral curve of the one
side reflectance on the side on which the antireflection film was
formed of the low reflection glass is shown in FIG. 14. Further,
the luminous reflectance is shown in Table 1.
Comparative Example 5
[0168] An interlayer comprising TiN.sub.x and an outermost layer
which is a SiCO layer were formed in the same manner as in Example
1 except that a mixed gas of Ar and CO.sub.2 (Ar/CO.sub.2=35/65:
flow ratio) was used as the mixed gas introduced to the second
chamber.
[0169] The film thicknesses of the respective layers in the
antireflection film, the refractive index of the outermost layer,
the content of C atoms in the outermost layer, and the abrasion
resistance 4 to 5 days after film deposition of the antireflection
film are shown in Table 1. Further, the spectral curve of the one
side reflectance on the side on which the antireflection film was
formed of the low reflection glass is shown in FIG. 14. Further,
the luminous reflectance is shown in Table 1.
Comparative Example 6
[0170] An interlayer comprising TiN.sub.x and an outermost layer
which is a SiCO layer were to formed in the same manner as in
Example 1 except that a mixed gas of Ar and CO.sub.2
(Ar/CO.sub.2=40/60: flow ratio) was used as the mixed gas
introduced to the second chamber.
[0171] The film thicknesses of the respective layers in the
antireflection film, the refractive index of the outermost layer,
the content of C atoms in the outermost layer, and the abrasion
resistance 4 to 5 days after film deposition of the antireflection
film are shown in Table 1. Further, the spectral curve of the one
side reflectance on the side on which the antireflection film was
formed of the low reflection glass is shown in FIG. 14. Further,
the luminous reflectance is shown in Table 1.
Comparative Example 7
[0172] An interlayer comprising TiN.sub.x and an outermost layer
comprising SiO.sub.2 containing no C were formed in the same manner
as in Example 1 except that the gas introduced to the second
chamber was changed to O.sub.2 gas.
[0173] The film thicknesses of the respective layers in the
antireflection film, the refractive index of the outermost layer,
the content of C atoms in the outermost layer, and the abrasion
resistance 4 to 5 days after film deposition of the antireflection
film are shown in Table 1. Further, the luminous reflectance is
shown in Table 1.
Example 5
Example for Preparation of Protective Plate for Plasma Display
[0174] A protective plate for a plasma display as shown in FIG. 10
was prepared by using the low reflection glass prepared in Example
1.
<Preparation of Sputtering Target>
[0175] Starting materials ZnO powder and TiO.sub.2 powder were
weighed in a molar ratio of ZnO:TiO.sub.2=90/10 and wet mixed in a
ball mill mixer for 24 hours, the mixture was dried by an
evaporator, the dried product was pulverized by a juicer mixer and
filtered through a sieve of 200 mesh to prepare a starting material
powder the particle size of which was adjusted. A graphite mold was
filled with the obtained starting material powder, which was
sintered under pressure by using a resistant heat type hot pressing
apparatus employing an argon gas as an atmospheric gas at a
temperature-raising rate of 350.degree. C./hr at a maximum
temperature of 1,150.degree. C. for a maximum temperature-retention
time of 2 hours under a pressure of 99 MPa (gauge pressure) to
obtain a sputtering target containing ZnO and Zn.sub.2TiO.sub.4 as
the main components. The contents (molar ratio) of ZnO and
Zn.sub.2TiO.sub.4 were calculated from the charge ratio of starting
materials ZnO and TiO.sub.2, whereupon
ZnO:Zn.sub.2TiO.sub.4=88:12.
[0176] The powder X-ray diffraction of the sputtering target was
measured. As the measuring method, first, the sputtering target was
formed into a powder by a pestle and a motar, the powder was put in
a container for X-ray diffraction measurement of 15 mm.times.15
mm.times.1 mm t (thickness), and measurement was carried out within
a range of 20.degree.<2.theta.<80.degree. by using an X-ray
diffraction apparatus manufactured by Mac Science. The obtained
data of the powder X-ray diffraction of the sputtering target are
shown in FIG. 15. As shown in FIG. 15, only a peak derived from ZnO
and a peak derived from Zn.sub.2TiO.sub.4 appeared, and no peak
derived from TiO.sub.2 appeared. This indicates that the
composition of the target comprises ZnO and Zn.sub.2TiO.sub.4. As a
result of the powder X-ray diffraction measurement, the integrated
intensity of ZnO [100] in the vicinity of 2.theta.=31.7.degree. was
116,966 [cps], the integrated intensity of Zn.sub.2TiO.sub.4 [311]
in the vicinity of 2.theta.=35.2.degree. was 76,676 [cps], and the
ratio was 60%.
<Preparation of Electroconductive Film>
[0177] On one surface of a polyethylene terephthalate film (PET
film) having a thickness of 100 .mu.m as a substrate, four layers
of laminated films each having a metal oxide layer A and a metal
layer laminated in this order were formed, and a metal oxide layer
A was formed as the outermost layer to form a conductive film on
the surface of the PET film thereby to obtain an electrically
conductive film.
[0178] That is, the structure of the conductive film was such that
in order from the substrate, a metal oxide layer A1 (film
thickness: 40 nm), a metal layer 1 (film thickness: 10 nm), a metal
oxide layer A2 (film thickness: 80 nm), a metal layer 2 (film
thickness: 10 nm), a metal oxide layer A3 (film thickness: 80 nm),
a metal layer 3 (film thickness: 10 nm), a metal oxide layer A4
(film thickness: 80 nm), a metal layer 4 (film thickness: 10 nm)
and a metal oxide layer A5 (film thickness: 40 nm). The total film
thickness of the laminated film was 360 nm.
[0179] The metal oxide layers A were formed by DC sputtering using
the above sputtering target. The film deposition conditions were
such that while a mixed gas comprising 95 vol % of an argon gas and
5 vol % of an oxygen gas was introduced to the DC sputtering
apparatus, the pressure and the charged electric power were
constant under 0.42 Pa (gauge pressure) at 3.75 W/cm.sup.2,
respectively. The film deposition time was such that the film
thickness of the layers A1 and A5 was 40 nm, and the film thickness
of the layers A2, A3 and A4 was 80 nm.
[0180] The metal layers are a film comprising 99 at % of silver and
1 at % of gold. The metal layers were formed by DC sputtering using
sputtering targets of silver and gold to achieve a desired
composition. The film deposition conditions were such that while an
argon gas was introduced to the DC sputtering apparatus, the
pressure and the charged electric power were constant under 0.42 Pa
(gauge pressure) at 2.5 W/cm.sup.2, respectively. The film
deposition time was such that the film thickness was 10 nm.
<Preparation of Protective Plate for Plasma Display>
[0181] On the surface of the PET film (resin film 56) side of the
obtained electroconductive film 54, a transparent adhesive layer 34
(acrylic adhesive, thickness: 25 .mu.m) was formed.
[0182] The low reflection glass 10 prepared in Example 1 was cut
into a predetermined size, chamfered and cleaned, and then heated
to 660.degree. C., and then air-cooled to conduct glass tempering
treatment.
[0183] On the side on which no antireflection film 14 was formed of
the low reflection glass 10, the electroconductive film 54 was
bonded by means of the above transparent adhesive layer 34. Then,
for the purpose of protecting the electroconductive film 58, a
resin film 38 (manufactured by TOYOBO CO., LTD, tradename: A4100)
was bonded on the surface of the electroconductive film 58 by means
of a colored adhesive layer 36 (acrylic adhesive, thickness: 25
.mu.m). Further, for the purpose of forming electrodes, portions
(electrode forming portions) on which no resin film was bonded were
left around the periphery of the electroconductive film.
[0184] Then, on the electrode forming portions, a silver paste
(manufactured by TAIYO INK MFG. CO., LTD., tradename: AF4810) was
screed printed by a nylon mesh #180 with an emulsifiable
concentrate thickness of 20 .mu.m and dried in a circulating hot
air oven at 85.degree. C. for 35 minutes to form electrodes 60.
TABLE-US-00001 TABLE 1 Interlayer TiO.sub.y TiN.sub.x Outermost
layer Film Film Film Scratch start load (g) Luminous thickness
thickness thickness Refractive C content 3 to 4 hours 4 to 5 days
reflectance (nm) (nm) (nm) index (mol %) later later (%) Ex. 1 -- 7
87.2 1.474 1.1 57.6 348.2 0.862 Comp. Ex. 1 -- 7 80.6 1.472 0.055
5.6 127.6 1.01 Comp. Ex. 2 -- 7 86.1 1.472 0.055 4.8 106.6 0.748
Ex. 2 14 -- 125.3 1.470 1.1 15.4 225.2 1.44 Comp. Ex. 3 14 -- 113.9
1.472 0.055 6.2 95.2 0.991 Comp. Ex. 4 14 -- 125.6 1.473 0.055 4.6
101.8 1.64 Ex. 3 -- 7 84.7 1.478 0.6 -- 109.3 1.13 Ex. 4 -- 7 84.8
1.485 1.6 -- 138.6 1.10 Comp. Ex. 5 -- 7 85.2 1.562 9.2 -- 115.7
3.03 Comp. Ex. 6 -- 7 84.8 1.618 12.2 -- 53.4 4.46 Comp. Ex. 7 -- 7
82.5 1.477 0.055 -- 48.3 2.66
INDUSTRIAL APPLICABILITY
[0185] The low reflection glass of the present invention is useful
as a protective plate for a plasma display, a low reflection glass
for a liquid crystal display, a low reflection glass for an organic
EL display, a cover glass for a solar battery, a glass for an
automobile, a glass for a railway vehicle, a glass for shipping, a
glass for a building material, etc.
[0186] The entire disclosure of Japanese Patent Application No.
2008-113857 filed on Apr. 24, 2008 including specification, claims,
drawings and summary is incorporated herein by reference in its
entirety.
MEANINGS OF SYMBOLS
[0187] 10: low reflection glass [0188] 10a: low reflection glass
[0189] 10b: low reflection glass [0190] 10c: low reflection glass
[0191] 10d: low reflection glass [0192] 12: glass substrate [0193]
14: antireflection film [0194] 14a: antireflection film [0195] 14b:
antireflection film [0196] 14c: antireflection film [0197] 14d:
antireflection film [0198] 16: interlayer [0199] 16a: layer (a)
[0200] 16b: layer (b) [0201] 18: outermost layer [0202] 20:
protective plate [0203] 30: electroconductive mesh layer
(conductive film) [0204] 32: protective plate [0205] 40: protective
plate [0206] 50: protective plate [0207] 52: protective plate
[0208] 58: conductive film [0209] 62: protective plate
* * * * *