U.S. patent application number 14/809074 was filed with the patent office on 2015-11-19 for display panel, method of manufacturing the same, and frit composition used in the display panel.
The applicant listed for this patent is Samsung Display Co., Ltd.. Invention is credited to Jin-Hwan JEON, Sun-Young JUNG, Ji-Young MOON, Seung-Yong SONG.
Application Number | 20150329412 14/809074 |
Document ID | / |
Family ID | 47353496 |
Filed Date | 2015-11-19 |
United States Patent
Application |
20150329412 |
Kind Code |
A1 |
JUNG; Sun-Young ; et
al. |
November 19, 2015 |
DISPLAY PANEL, METHOD OF MANUFACTURING THE SAME, AND FRIT
COMPOSITION USED IN THE DISPLAY PANEL
Abstract
Provided are display panel, method of manufacturing the same,
and frit composition used in the display panel. A display panel
comprising: a first substrate, a second substrate facing the first
substrate and a frit bonding the first substrate and the second
substrate together, wherein the frit has an optical density of more
than about 0.0683 .mu.m for laser light of any one wavelength in a
wavelength range of about 760 to about 860 nm.
Inventors: |
JUNG; Sun-Young;
(Yongin-city, KR) ; JEON; Jin-Hwan; (Yongin-city,
KR) ; SONG; Seung-Yong; (Yongin-city, KR) ;
MOON; Ji-Young; (Yongin-city, KR) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Samsung Display Co., Ltd. |
Yongin-city |
|
KR |
|
|
Family ID: |
47353496 |
Appl. No.: |
14/809074 |
Filed: |
July 24, 2015 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
13341791 |
Dec 30, 2011 |
9130191 |
|
|
14809074 |
|
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Current U.S.
Class: |
156/89.11 |
Current CPC
Class: |
H01L 51/5246 20130101;
H01L 2251/55 20130101; C03C 8/14 20130101; C03C 8/24 20130101 |
International
Class: |
C03C 8/24 20060101
C03C008/24 |
Foreign Application Data
Date |
Code |
Application Number |
Jun 17, 2011 |
KR |
10-2011-0059177 |
Claims
1. A method of manufacturing a display panel, the method
comprising: preparing a first substrate and a second substrate;
coating a frit composition, which has an optical density of more
than about 0.0683/.mu.m for laser light of a wavelength of about
810 nm, on the second substrate; stacking the first substrate on
the frit composition; and sintering the frit composition by
irradiating the laser light of the wavelength of about 810 nm to
the frit composition.
2. The method of claim 1, wherein the irradiating of the laser
light is performed with a power of about 12.5 to about 13.0 W.
3. The method of claim 1, wherein the frit composition comprises
vanadium-based mother glass and further comprising plasticizing the
frit composition at a temperature of about 300 to about 500.degree.
C. and in a workspace in an atmosphere which contains about 30 to
about 40% by volume of N.sub.2, after the coating of the frit
composition.
4. The method of claim 1, wherein the frit composition comprises
bismuth-based mother glass, and, in the coating of the frit
composition, a frit composition, which has an optical density of
about 0.1567/.mu.m or greater for the laser light of the wavelength
of about 810 nm, is coated on the second substrate.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application is a divisional application which claims
priority under 35 U.S.C .sctn.120 from U.S. patent application Ser.
No. 13/341,791, filed Dec. 30, 2011, which claims priority to and
the benefit of Korean Patent Application No. 10-2011-0059177 filed
on Jun. 17, 2011 in the Korean Intellectual Property Office, the
disclosure of each of which is incorporated herein by
reference.
BACKGROUND
[0002] 1. Field
[0003] The present embodiments relate to a display panel including
a glass package sealed with a frit, a method of manufacturing the
display panel, and a frit composition used in the display
panel.
[0004] 2. Description of the Related Technology
[0005] An organic light-emitting diode (OLED) display is a
self-luminous display and includes an organic material between two
electrodes. The OLED display emits light when injected electrons
and holes recombine in the organic material.
[0006] Electrodes and an organic layer within an OLED display are
readily damaged by interaction with oxygen and moisture that get
into the OLED display. Thus, a frit is interposed between glass
substrates to seal them and protect internal devices against oxygen
and moisture.
[0007] To improve the sealing capability of a frit, an effective
seal width of the frit should be increased. The effective seal
width of the frit depends on how effectively the frit is heated and
melted when upper and lower substrates are bonded together.
SUMMARY
[0008] Aspects of the present embodiments provide a display panel
with a superior sealing capability.
[0009] Aspects of the present embodiments also provide a method of
manufacturing a display panel with a superior sealing
capability.
[0010] Aspects of the present embodiments also provide a frit
composition with a superior sealing capability.
[0011] However, aspects of the present embodiments are not
restricted to the one set forth herein. The above and other aspects
of the present embodiments will become more apparent to one of
ordinary skill in the art to which the present embodiments pertain
by referencing the detailed description of the present embodiments
given below.
[0012] According to an aspect of the present embodiments, there is
provided
[0013] A display panel comprising:
[0014] a first substrate, a second substrate facing the first
substrate and a frit bonding the first substrate and the second
substrate together, wherein the frit has an optical density of more
than about 0.0683 .mu.m for laser light of any one wavelength in a
wavelength range of about 760 to about 860 nm.
[0015] According to another aspect of the present embodiments,
there is provided
[0016] A method of manufacturing a display panel, the method
comprising:
[0017] preparing a first substrate and a second substrate, coating
a frit composition, which has an optical density of more than about
0.0683 .mu.m for laser light of a wavelength of 810 nm, on the
second substrate, stacking the first substrate on the frit
composition and sintering the frit composition by irradiating the
laser light of the wavelength of 810 nm to the frit
composition.
BRIEF DESCRIPTION OF THE DRAWINGS
[0018] The above and other aspects and features of the present
embodiments will become more apparent by describing in detail
example embodiments thereof with reference to the attached
drawings, in which:
[0019] FIG. 1 is a schematic layout view of a display panel
according to an example embodiment;
[0020] FIG. 2 is a cross-sectional view of the display panel shown
in FIG. 1;
[0021] FIG. 3A is a scanning electron microscope (SEM) photograph
of a frit;
[0022] FIG. 3B is a schematic diagram illustrating a seal width of
the frit of FIG. 3A;
[0023] FIG. 4 is a flowchart illustrating a method of manufacturing
a display panel according to an example embodiment;
[0024] FIG. 5 is a graph illustrating the relationship between the
content of a vanadium compound in a vanadium-based frit and the
optical density of the vanadium-based frit;
[0025] FIG. 6 is a diagram illustrating a seal width of each sample
of FIG. 5;
[0026] FIG. 7 is a graph illustrating the relationship between the
type of a pigment contained in a bismuth-based frit and the optical
density of the bismuth-based frit;
[0027] FIG. 8 is a diagram illustrating a seal width of each sample
of FIG. 7;
[0028] FIG. 9 is a graph illustrating the relationship between the
content of Mn in a frit having a Mn-containing pigment and the
optical density of the frit;
[0029] FIG. 10 is a diagram illustrating an effective seal width of
each sample of FIG. 9; and
[0030] FIG. 11 is a graph illustrating an optical density range of
a bismuth-based frit which is required for laser sealing.
DETAILED DESCRIPTION
[0031] The present embodiments will now be described more fully
hereinafter with reference to the accompanying drawings, in which
preferred embodiments are shown. The present embodiments may,
however, be embodied in different forms and should not be construed
as limited to the embodiments set forth herein. Rather, these
embodiments are provided so that this disclosure will be thorough
and complete, and will fully convey the scope of the embodiments to
those skilled in the art. The same reference numbers indicate the
same components throughout the specification. In the attached
figures, the thickness of layers and regions is exaggerated for
clarity.
[0032] Unless defined otherwise, all technical and scientific terms
used herein have the same meaning as commonly understood by one of
ordinary skill in the art to which these embodiments belong. It is
noted that the use of any and all examples, or example terms
provided herein is intended merely to better illuminate the
embodiments and is not a limitation on the scope of the embodiments
unless otherwise specified. Further, unless defined otherwise, all
terms defined in generally used dictionaries may not be overly
interpreted.
[0033] FIG. 1 is a schematic layout view of a display panel 100
according to an example embodiment. FIG. 2 is a cross-sectional
view of the display panel 100 shown in FIG. 1.
[0034] Referring to FIGS. 1 and 2, the display panel 100 includes a
first substrate 400, a second substrate 300, and a frit 200
interposed between the first substrate 400 and the second substrate
300.
[0035] The first substrate 400 may be made of a glass material such
as borosilicate glass, soda-lime glass, or a mixture of the same.
However, the present embodiments are not limited thereto.
[0036] The first substrate 400 may receive thermal stress from a
heating member (such as a laser) used in the process of attaching
the frit 200 to the first substrate 400. Thus, the first substrate
400 may be made of a material that hardly absorbs a wavelength
range corresponding to thermal energy generated from the heating
member.
[0037] A plurality of micro devices for light emission may be
formed on the first substrate 400. For example, a plurality of
light-emitting units may be formed on the first substrate 400.
Here, the light-emitting units may be organic light-emitting diodes
(OLEDs), and each of the OLEDs may have a stacked structure of a
cathode electrode which provides electrons, an electron injecting
layer which transports the electrons provided by the cathode
electrode, an organic emitting layer which emits light when
transported electrons and holes react with each other to excite
organic molecules, a hole injecting layer which transports holes
provided by an anode electrode, and the anode electrode which
provides the holes.
[0038] A plurality of thin-film transistors (TFTs) may further be
formed on the first substrate 400. When a light-emitting unit
includes an OLED, a TFT may be connected to at least one of the
cathode electrode and the anode electrode of the OLED to control
the provision of current to the connected one or ones of the
cathode electrode and the anode electrode.
[0039] The second substrate 300 faces the first substrate 400 and
covers the light-emitting units located on the first substrate 400.
Like the first substrate 400, the second substrate 300 may be made
of a glass material such as borosilicate glass, soda-lime glass, or
a mixture of the same. In addition, like the first substrate 400,
the second substrate 300 may be made of a material that hardly
absorbs the wavelength range corresponding to the thermal energy
generated from the heating member.
[0040] The frit 200 is interposed between the first substrate 400
and the second substrate 300 and provides a sealed space between
the first substrate 400 and the second substrate 300. To provide a
sufficiently large sealed space in a central region of the first
and second substrates 400 and 300, the frit 200 may be formed in
peripheral regions thereof. The frit 200 may be formed by sintering
a frit composition.
[0041] To fully seal a display region from the outside environment
with the frit 200, a seal width of the frit 200 should be large
enough to become an effective seal width. Here, the seal width may
denote a width which enables the frit 200 to connect the frit
substrate 400 and the second substrate 300 after being melted by
thermal energy it absorbs and then sintered and which enables the
frit 200 to block outside air and moisture. The seal width will now
be described in greater detail with reference to FIGS. 3A and
3B.
[0042] FIG. 3A is a scanning electron microscope (SEM) photograph
of the frit 200. FIG. 3B is a schematic diagram illustrating the
seal width of the frit 200 of FIG. 3A. Referring to FIGS. 3A and
3B, a width of the frit 200 attached onto the first and second
substrates 400 and 300 is not always equal to a width D of the
entire frit 200. As shown in FIG. 3B, a width of the frit 200 in a
region in which the frit 200 is attached onto the second substrate
300 to contact the second substrate 300 is equal to the maximum
width D of the frit 200. However, a width d of the frit 200 in a
region in which the frit 200 is attached onto the first substrate
400 to contact the first substrate 400 may be smaller than the
maximum width D of the frit 200 due to empty spaces 500 and 550 at
edges of the frit 200. In this case, a width that contributes to
sealing the display panel 100 from outside air and moisture is the
width d of the frit 200 attached onto the first substrate 400.
Accordingly, the seal width is determined to be the width d of the
frit 200 actually attached onto the first substrate 400, excluding
the edges of the frit 200 (e.g., the empty spaces 500 and 550)
which are not connected to the first substrate 400.
[0043] Unlike in the example illustrated in FIGS. 3A and 3B, the
width of the frit 200 attached onto the first substrate 400 may
also be smaller than the width D of the entire frit 200. In this
case, a smaller one of the width of the frit 200 attached onto the
first substrate 400 and the width of the frit 200 attached onto the
second substrate 300 is determined to the seal width.
[0044] The effective seal width may denote a seal width large
enough to enable the frit 200 to connect the first substrate 400
and the second substrate 300 and block outside air and moisture.
For example, when a ratio of a seal width to the maximum width D of
the frit 200 is about 0.7 or higher, it can be determined that the
effective seal width has been formed. Specifically, when the
maximum width D of the frit 200 is 600 .mu.m, if a seal width that
enables the frit 200 to block outside air and moisture is 420 .mu.m
or more, it can be determined that the effective seal width has
been formed. Likewise, when the maximum width D of the frit 200 is
1200 .mu.m, a seal width of 840 .mu.m or more may be determined to
be the effective seal width.
[0045] The seal width of the frit 200 may be symmetrical with
respect to a center line of the frit 200. However, the seal width
may also be in various forms.
[0046] After materials that form the frit 200 are heated using the
heating member, some of the materials that form the frit 200 may
not be properly sintered into the frit 200. The materials that are
not properly sintered do not contribute to the sealing of the
display panel 100. A seal width formed large enough to exceed the
effective seal width through a smooth sintering process is closely
related to the degree of sealing of the display panel 100.
[0047] To increase the effective seal width of the frit 200, it is
desirable for the frit 200 to fully absorb thermal energy from the
heating member. For example, the use of a frit having a high
optical density, which indicates the degree of absorption of
radiant energy, is advantageous to the sealing of the display panel
100. The heating member may be laser light of any one wavelength in
a wavelength range of 760 to 860 nm.
[0048] The optical density may also be referred to as an extinction
coefficient and may be measured in [/.mu.m]. Absorbance and
extinction coefficient may satisfy the following equations.
Absorbance=A=log(1/t)=log(1/(It/Io))=-log(It/100)=.epsilon.CL,
Extinction coefficient=A/L=.epsilon.C,
where t=It/Io represents the intensity of transmitted light/the
intensity of incident light (the incident light: 100%, the
transmitted light: measured transmittance (%)), .epsilon.
represents a proportional constant, C represents the concentration
of a sample (it is assumed that the concentration of the sample is
constant), and L represents the length (thickness) of the
sample.
[0049] When the transmittance of a sample for laser light of any
one wavelength in a wavelength range of about 760 to about 860 nm,
for example, laser light of 810 nm is 20%, if the sample has a
thickness of 5 .mu.m, A (absorbance)=-log(20/100)=0.69897, and
A/L=.epsilon.C (extinction coefficient)=0.69897/5
.mu.m=0.139794/.mu.m.
[0050] Hereinafter, an optical density range that ensures superior
sealing performance of the frit 200 and methods of achieving
optical densities in this optical density range will be
described.
[0051] In a frit-sintering process using a laser, an optical
density of a frit determines a seal width of the frit. If a minimum
optical density for forming an effective seal width can be
identified, the time required to select materials that form the
frit can be reduced based on the identification result, which, in
turn, reduces the entire frit process. An optical density that
allows a frit to have an effective seal width after being
irradiated with laser light of 810 nm varies according to
characteristics of mother glass or other components of the frit.
Components of a frit and a minimum optical density of the frit will
hereinafter be described in detail.
[0052] A frit may include mother glass and ceramic filler. In some
embodiments, the mother glass may be vanadium-based mother glass
including a plurality of compounds. For example, the vanadium-based
mother glass may include about 40 to about 50% by mole of
V.sub.2O.sub.5, which is a vanadium-based compound, based on the
total content of the frit and may further include TeO.sub.2, BaO,
and ZnO.
[0053] The ceramic filler is distributed within the mother glass to
maintain the shape of the sintered frit. In addition, the ceramic
filler controls a coefficient of thermal expansion (CTE) of the
frit to maintain the mechanical strength of the frit. More
specifically, the ceramic filler may be made of a material having a
relatively lower CTE than the mother glass. Therefore, even when
the mother glass has a relatively high CTE, since the CTE of the
mother glass is offset by the CTE of the ceramic filler, the CTE of
the frit can be maintained low. A lower CTE increases mechanical
strength against heat. Therefore, the ceramic filler contributes to
an increase in the mechanical strength of the frit. When the
vanadium-based mother glass is used as the mother glass, the
ceramic filler mixed with the vanadium-based mother glass may be,
e.g., Zr.sub.2(WO.sub.4)(PO.sub.4).sub.2.
[0054] As verified through experimental examples which will be
described later, a vanadium-based frit should have an optical
density of more than about 0.0683/.mu.m in order to have an
effective seal width after being irradiated with laser light of any
one wavelength in a wavelength range of about 760 to about 860 nm,
for example, laser light of 810 nm. An upper limit of the optical
density of the frit may be 0.2/.mu.m. An optical density of
0.2/.mu.m or less can prevent sintering defects at each frit height
due to a reduction in the transmittance of laser light.
[0055] The content of a vanadium-based component in the
vanadium-based frit may change the optical density of the frit.
Specifically, the vanadium-based component may be, e.g.,
V.sub.2O.sub.5. When the content of V.sub.2O.sub.5 in the
vanadium-based frit is about 40 to about 50% by mole, a high
optical density can be obtained. In some other embodiments, the
vanadium-based frit may further include V.sub.2O.sub.4. In this
case, the sum of the content of V.sub.2O.sub.4 and the content of
V.sub.2O.sub.5 may be about 40 to about 50% by mole. Since
V.sub.2O.sub.4 is more brownish in color than V.sub.2O.sub.5, a
greater content of V.sub.2O.sub.4 may lead to a higher absorption
rate of thermal energy, thereby increasing the optical density of
the vanadium-based frit.
[0056] In order to increase the content of V.sub.2O.sub.4 in the
frit, a frit composition may be plasticized in a N.sub.2
atmosphere. Specifically, the vanadium-based mother glass that
contains V.sub.2O.sub.5 is yellowish due to a vanadium component of
a pentavalent ion. If a vanadium-based compound has a chemical
reaction in a N.sub.2 environment, VO.sub.2 is contained in the
resultant compound. The chemical reaction formula of the
vanadium-based mother glass in the N.sub.2 environment is as
follows.
V.sub.2O.sub.5+C.fwdarw.2VO.sub.2+CO.sub.2.uparw.
[0057] Therefore, the resultant compound includes a vanadium
component of a tetravalent ion, and vanadium of the tetravalent ion
is brownish in color. This corresponds to a condition that
increases the frit's absorption rate of thermal energy, thus
increasing the optical density of the frit.
[0058] During the process of plasticizing the frit, a flow rate of
oxygen in a workspace should be maintained at a predetermined rate
or higher in order to induce a desired chemical reaction.
Therefore, the flow rate of N.sub.2 in the workspace for the
plasticizing process needs to be adjusted in view of the flow rate
of oxygen in the workspace. For example, the flow rate of N.sub.2
in the workspace for the plasticizing process may be 30 to 40% by
volume.
[0059] In some other embodiments, the mother glass of the frit may
be bismuth-based mother glass including a plurality of compounds.
The bismuth-based glass may include 30 to 45% by mole of
Bi.sub.2O.sub.3 based on the total content of the frit and may
further include ZnO, B.sub.2O.sub.3, BaO, Al.sub.2O.sub.3,
SiO.sub.2, and MgO. Here, the ceramic filler that can be mixed with
the bismuth-based mother glass may be, e.g.,
Mg.sub.2(Al.sub.4O.sub.3(SiO.sub.3).sub.5)).
[0060] As verified through the experimental examples which will be
described later, a bismuth-based frit should have an optical
density of more than about 0.1567 .mu.m or more in order to have an
effective seal width after being irradiated with laser light of any
one wavelength in a wavelength range of about 760 to about 860 nm,
for example, laser light of 810 nm. The reason why the
bismuth-based frit requires a higher optical density than the
vanadium-based frit is that its material characteristics such as
the color of its mother glass are different from those of the
vanadium-based frit and, accordingly, it requires a different
amount of thermal energy.
[0061] The bismuth-based frit may further include a pigment in
order to increase its optical density. The pigment added to the
frit can change the color of the entire frit. Since the
bismuth-based glass is whitish due to properties of bismuth, it is
not efficient in absorbing energy provided by the heating member.
For this reason, a pigment may be added to the bismuth-based mother
glass to change the color of the frit, so that the frit can better
absorb radiant energy. When a Mn-containing pigment is added to the
frit, the optical density of the frit is increased compared with
when not added. Accordingly, the increased optical density of the
frit may increase the effective seal width of the frit. Here, the
Mn-containing pigment may be one or more materials selected from
the group consisting of MnO, MnO.sub.2 and Mn.sub.3O.sub.4. For
example, Mn.sub.3O.sub.4 added to the frit significantly increases
the optical density of the frit, which, in turn, ensures a
sufficiently large effective seal width.
[0062] An increase in the content of the Mn-containing pigment in
the bismuth-based frit leads to an increase in the optical density
of the frit, resulting in an increase in the effective seal width
of the frit. From this perspective, the content of the
Mn-containing pigment in the entire frit should be 9.9% by mole or
more. To prevent sintering defects at each frit height due to a
reduction in the transmittance of laser light, the content of the
Mn-containing pigment in the entire frit should be 11.01% by
mole.
[0063] In some embodiments, the addition of a pigment to the frit
may induce melanization of the frit. The melanized frit can better
absorb thermal energy. Therefore, the pigment added to the frit
increases the absorption rate of energy generated from a laser. The
increased absorption rate of energy increases the optical density
of the frit, thus increasing the effective seal width of the frit.
A pigment can be added directly to the mother glass or can be added
to the frit as an additional component, in addition to the mother
glass and the filler.
[0064] The Mn-containing pigment can be added directly to the
mother glass or can be added as an additional component, in
addition to the mother glass and the filler. An excessive increase
in Mn content in the mother glass may degrade unique
characteristics of the mother glass. Specifically, the mother
glass, which is a glass component, has a certain flow when melted
at an appropriate temperature. However, if the content of Mn in the
mother glass exceeds a predetermined value, the flow of the mother
glass changes, making it difficult to sinter the frit. Therefore,
the amount of the Mn-containing pigment added directly to the
mother glass may be limited to a predetermined amount. From this
perspective, one or more materials selected from the group
consisting of MnO, MnO.sub.2 and Mn.sub.3O.sub.4 may be added to
the mother glass in an amount of 0.1 to 2% by mole based on the
total content of the frit, and other components may be added to the
mother glass as pigments separate from the mother glass.
[0065] A pigment containing one or more materials selected from the
group consisting of MnO, MnO.sub.2 and Mn.sub.3O.sub.4 may be added
not only to the frit based on the bismuth-based mother glass but
also to the frit based on the vanadium-based mother glass.
[0066] Hereinafter, a method of manufacturing a display panel
according to an example embodiment will be described. FIG. 4 is a
flowchart illustrating a method of manufacturing a display panel
according to an example embodiment.
[0067] Referring to FIGS. 1, 2 and 4, a frit composition is coated
on a second substrate 300 (operation S100). The frit composition
may be coated not on a first substrate 400 on which light-emitting
units are disposed but on the second substrate 300 which covers the
light-emitting units. In some cases, the frit composition may be
coated on the first substrate 400. The frit composition may be
coated on the second substrate 300 using, but not limited to, a
screen printing method. The frit composition coated on the second
substrate 300 may be gel-state paste formed by adding oxide powder
and an organic material to glass powder.
[0068] The coated frit composition is plasticized (operation S200).
To attach the gel-state frit paste onto the second substrate 300 as
a solid-state frit 200, the frit composition is plasticized in a
workspace such as a chamber. If the frit composition is a
vanadium-based frit composition, the workspace may be put in a
N.sub.2 environment. Here, a flow rate of N.sub.2 in the workspace
may be 30 to 40% by volume or less.
[0069] The plasticizing temperature may be in a range of from about
300 to about 500.degree. C., preferably, about 400.degree. C. In
this plasticizing process, the organic material dissipates into the
air, and the gel-state paste hardens to be attached onto the second
substrate 300 as the solid-state frit 200.
[0070] The first substrate 400 is placed on the plasticized frit
200 (operation S300). The first substrate 400 having the
light-emitting units on a surface thereof is placed to face the
second substrate 300 having the frit 200 attached thereto.
[0071] Finally, thermal energy is provided to the frit 200 using a
heating member (operation S400). The heating member may be laser
light of any one wavelength in a wavelength range of about 760 to
about 860 nm, for example, laser light of 810 nm. Laser irradiation
may be performed with a power of about 12.5 to about 13.0 W. After
the first substrate 400 is placed on the frit 200, laser light of
810 nm may be irradiated to a display panel 100. Accordingly, the
frit 200 is melted and attached to the first substrate 400, thereby
bonding the first substrate 400 and the second substrate 300
together. Here, if the frit 200 has an optical density of
0.0683/.mu.m or greater, a sufficient large effective seal width
can be formed as described above. Therefore, when the first
substrate 400 and the second substrate 300 are attached to each
other by this frit 200, oxygen and moisture can be prevented from
getting into a pixel region.
[0072] The present embodiments will now be described in further
detail with reference to the following experimental examples.
Information not provided below can be readily inferred by those of
ordinary skill in the art, and thus a description thereof will be
omitted.
Experimental Example 1
Relationship Between the Optical Density and Seal Width of a
Vanadium-Based Frit
[0073] Four frit samples R1 through R4 having different optical
densities were prepared by adjusting the content of vanadium in a
frit. Vanadium content in the frit samples R1 through R4 satisfied
R1<R2<R3<R4. As shown in FIG. 5, the vanadium content in
each of the first samples R1 through R4 was adjusted such that R1
had an optical density of 0.0683/.mu.m, R2 had an optical density
of 0.0795/.mu.m, R3 had an optical density of 0.0892/.mu.m and R4
had an optical density of 0.1483/.mu.m for laser light of 810
nm.
[0074] Each of the frit samples R1 through R4 was coated to a width
of 600 .mu.m, and laser light of 810 nm and with an energy of 12.5
W was irradiated. However, since a seal width was not formed at all
in the case of R1, the energy of the laser light was increased to
15.5 W, and then the experiment was conducted again. The results
are shown in Table 1 and FIGS. 5 and 6. In Table 1, it is
determined that an effective seal width has been formed when a
ratio of a seal width to a frit width is 0.7 or higher.
TABLE-US-00001 TABLE 1 Formation of Optical density Seal width of
Seal width/ effective seal Sample (/.mu.m) frit (.mu.m) frit width
width R1 0.0683 369 0.615 X R2 0.0795 476 0.793 .largecircle. R3
0.0892 491 0.818 .largecircle. R4 0.1483 505 0.842
.largecircle.
[0075] Referring to Table 1 and FIGS. 5 and 6, the effective seal
width was not formed in the case of R1 although the energy of the
laser light was significantly increased. On the other hand, a
sufficiently large effective seal width was formed in the case of
R2 and R4, even with an energy of 12.5 W, and R4 had a largest seal
width. A higher optical density led to a greater seal width.
[0076] It can be understood from the above results that a
vanadium-based frit can have an effective seal width only when its
optical density exceeds 0.0683/.mu.m.
Experimental Example 2
Relationship Between the Optical Density and Seal Width of a
Bismuth-Based Frit with or without a Mn-Containing Pigment
[0077] A frit sample P1 was prepared without adding a
Mn.sub.3O.sub.4-containing pigment to a bismuth-based frit, and
another frit sample P2 was prepared by adding the
Mn.sub.3O.sub.4-containing pigment to the bismuth-based frit. Then,
optical densities of the frit samples P1 and P2 were measured for
laser light of 810 nm. The frit samples P1 and P2 were coated to a
width of 600 .mu.m, and laser light of 810 nm and with an energy of
12.5 W was irradiated. Then, seal widths of the frit samples P1 and
P2 were measured, and the results are shown in Table 2 and FIGS. 7
and 8.
TABLE-US-00002 TABLE 2 Formation of Optical density Seal width of
Seal width/ effective seal Sample (/.mu.m) frit (.mu.m) frit width
width P1 0.0615 0 0 X P2 0.1732 467 0.778 .largecircle.
[0078] Referring to Table 2 and FIGS. 7 and 8, the measured optical
density of the frit sample P1 without the
Mn.sub.3O.sub.4-containing pigment was only 0.0615/.mu.m, while the
measured optical density of the frit sample P2 with the
Mn.sub.3O.sub.4-containing pigment was 0.1732/.mu.m. The frit
sample P2 had a far higher optical density than the frit sample P1.
Referring to Table 2 and FIG. 7, a seal width was not formed at all
in the case of P1. On the other hand, the seal width of the frit
sample P2 having the Mn.sub.3O.sub.4-containing pigment was 467
.mu.m, thus securing a sufficiently large seal width.
[0079] It can be understood from the above results that the
addition of a Mn.sub.3O.sub.4-containing pigment to a frit
increases the optical density of a frit, thus ensuring a
sufficiently large effective seal width.
Experimental Example 3
Seal Width of a Bismuth-Based Frit According to Mn Content in the
Bismuth-Based Frit
[0080] Three frit samples D1 through D3 having different optical
densities were prepared by adjusting the content of a
Mn.sub.3O.sub.4-containing pigment in a bismuth-based frit. As
shown in Table 3, the content of Mn.sub.3O.sub.4 in mother glass
was 0.5% by mole in the case of D1, 1.0% by mole in the case of D2,
and 2.0% by mole in the case of D3. In addition to the mother
glass, 8 to 9% by mole of the Mn.sub.3O.sub.4-containing pigment
was added to each of the frit samples D1 through D3.
[0081] Each of the frit samples D1 through D3 was coated to a width
of 600 .mu.m, and laser light of 810 nm and with an energy of 12.5
W was irradiated. Then, seal widths of the frit samples D1 through
D3 were measured. The results are shown in Table 3 and FIGS. 9 and
10.
TABLE-US-00003 TABLE 3 Mn content in Formation of mother glass Seal
width of Seal width/ effective seal Sample (mol %) frit (.mu.m)
frit width width D1 0.5 450 0.750 .largecircle. D2 1.0 478 0.797
.largecircle. D3 2.0 498 0.830 .largecircle.
[0082] Referring to Table 3 and FIGS. 9 and 10, a greater content
of Mn.sub.3O.sub.4 in a frit led to a greater seal width of the
frit. In addition, an effective seal width was formed in all of the
frit samples D1 through D3.
[0083] It can be understood from the above results that it is
desirable to increase the content of Mn.sub.3O.sub.4 in order to
increase the effective seal width of a frit.
Experimental Example 4
Optical Density Range of a Bismuth-Based Frit for Laser Sealing
[0084] To find out an optical density range for laser sealing,
experiments were conducted by varying a method of adding a
Mn.sub.3O.sub.4-containing pigment to a bismuth-based frit.
[0085] A `Bi mother glass` sample was prepared without adding the
Mn.sub.3O.sub.4-containing pigment to a frit, and a `Bi Black
mother glass` sample was prepared by adding the
Mn.sub.3O.sub.4-containing pigment only to mother glass. In
addition, a `Bi Black mother glass+pigment` sample was prepared by
adding the Mn.sub.3O.sub.4-containing pigment not only to the
mother glass but also to the frit.
[0086] Each frit sample was irradiated with laser light of 810 nm
and with an energy of 12.5 W to see if it had an effective seal
width. The results are shown in Table 4 and FIG. 11.
TABLE-US-00004 TABLE 4 Optical density Formation of effective
Sample (/.mu.m) seal width Bi mother glass 0.0162 Not formed Bi
Black mother glass 0.0284 Not formed Bi mother glass + pigment
0.1004 Not formed although a seal width for connecting both
substrates was formed Bi Black mother glass + 0.1567 Formed
pigment
[0087] Referring to Table 2 and FIG. 11, the optical density of the
`Bi mother glass` sample was close to zero. Although the `Bi Black
mother glass` sample showed a higher optical density than the `Bi
mother glass` sample, it did not have an effective seal width.
[0088] The `Bi mother glass+pigment` sample had an optical density
of 0.1004/.mu.m. At this value, the `Bi mother glass+pigment`
sample had a seal width for connecting both substrates, but not an
effective seal width.
[0089] The `Bi Black mother glass+pigment` sample had an optical
density of 0.1567/.mu.m and thus an effective seal width.
[0090] As apparent from the above results, when the `Bi Black
mother glass+pigment` sample is used as a frit for a display panel,
a minimum optical density of 0.1567 .mu.m is required to form an
effective seal width for connecting and sealing both substrates of
the display panel.
[0091] In concluding the detailed description, those skilled in the
art will appreciate that many variations and modifications can be
made to the preferred embodiments without substantially departing
from the principles of the present embodiments. Therefore, the
disclosed preferred embodiments are used in a generic and
descriptive sense only and not for purposes of limitation.
* * * * *