JP2003192376A - Low-melting glass, glass ceramic composition and plasma display panel back substrate - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a low-melting glass and a glass ceramic composition capable of suppressing or preventing the formation of a silver colloid in barrier ribs of a plasma display panel back substrate. <P>SOLUTION: The low-melting glass comprises SiO<SB>2</SB>; 10-40%, B<SB>2</SB>O<SB>3</SB>; 20-45%, PbO; 1-60%, Al<SB>2</SB>O<SB>3</SB>+TiO<SB>2</SB>+ZrO<SB>2</SB>; 1-25%, MgO+CaO+SrO+BaO+ZnO; 4-20% and CeO<SB>2</SB>+CuO; 0.1-1% by mol. The glass ceramic composition comprises a ceramic filler and powder of the low-melting glass. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a plasma display panel (PDP) rear substrate and a low melting point glass suitable for forming a dielectric layer of the substrate.

[0002]

2. Description of the Related Art PD, which is a thin flat panel color display device
P is manufactured by combining a back substrate having partition walls and a front substrate used as a display surface so as to face each other, and an image is generated by generating plasma discharge in the cells partitioned by the partition walls. It is formed.

The back substrate is manufactured, for example, as follows. First, a silver electrode is formed as an address electrode on a glass substrate. The address electrode width (line width) and electrode spacing (pitch) are typically 80 μm and 30 respectively.
It is 0 μm. Next, the silver electrode is coated with a dielectric layer having a thickness of about 10 μm for protection thereof, and then a partition wall is formed on the dielectric layer. Finally, the phosphor is applied on the partition.

The silver electrode is coated with the dielectric layer in the following manner, for example. That is, powder of a low melting point glass such as lead borosilicate glass is mixed with a ceramics filler as necessary to form a paste. The obtained glass paste is applied onto a glass substrate on which a silver electrode is formed, dried and then baked at 500 to 620 ° C. to form a silver electrode-covered dielectric layer.

[0005]

In recent years, there has been a demand for reduction in power consumption of PDPs, and as a solution to this, a low dielectric constant partition wall, for example, a partition wall having a relative dielectric constant ε of 12 or less at 20 ° C. and 1 MHz. Is proposed. However, the low dielectric constant partition wall has a problem that silver diffuses from the silver electrode and silver colloid is formed in the partition wall, and the partition wall turns yellow. It is an object of the present invention to provide a low melting point glass, a glass ceramic composition and a plasma display panel rear substrate which can suppress or prevent the formation of silver colloid in the partition walls.

[0006]

Means for Solving the Problems The present invention essentially comprises SiO ₂ : 10 to 40% in terms of mol% based on the following oxides:
_{B 2 O 3: 20~45%,} PbO: 1~60%, Al 2
_{O 3 + TiO 2 + ZrO 2} : 1~25%, MgO + Ca
O + SrO + BaO + ZnO: 4 to 20%, CeO ₂ +
A low melting point glass comprising CuO: 0.1 to 1% is provided.

Further, there is provided a glass-ceramic composition consisting essentially of a ceramic filler and the powder of the low melting point glass. Further, an address electrode is formed on a glass substrate, the address electrode is covered with a dielectric layer containing at least one of CeO ₂ and CuO, and partition walls are formed on the dielectric layer. A plasma display panel rear substrate is provided.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION The low melting point glass of the present invention (hereinafter referred to as the glass of the present invention) is usually used in the form of powder. This powdered glass is mixed with a ceramics filler or the like, if necessary, and then kneaded with a vehicle to form a paste. This glass paste is applied to a predetermined portion of the base and baked.

The vehicle is usually ethyl cellulose,
A resin such as nitrocellulose is dissolved in a solvent such as α-terpineol, butyl carbitol acetate, and isopentyl acetate. Further, the glass of the present invention is P
Dielectric layer of DP back substrate (hereinafter referred to as back dielectric)
When used for formation, the base is a glass substrate on which address electrodes are formed, and the address electrodes are typically silver electrodes.

The temperature at which the calcination is carried out is usually 500 to
620 ° C. If the temperature is lower than 500 ° C., a part of the resin remains on the back dielectric, and there is a possibility that the residual resin becomes a gas and is released into the cell when sealing the back substrate and the front substrate or during plasma discharge. If it exceeds 620 ° C, the glass substrate may be deformed.

The softening point T _S of the glass of the present invention is 450-6.
It is preferably 50 ° C. If the temperature is lower than 450 ° C., the glass may flow excessively during the above-mentioned firing, and coarse bubbles may be formed. More preferably, it is 500 ° C. or higher. If it exceeds 650 ° C, the fluidity of the glass at the time of firing is lowered, and a dense back surface dielectric may not be obtained. More preferably 620 ° C
The temperature is particularly preferably below 600 ° C.

The average linear expansion coefficient α of the glass of the present invention at 50 to 350 ° C. is 65 × 10 ^{−7 to} 85 × 10 ⁻⁷ /.
C. is preferred. Outside this range, expansion matching with the underlying glass substrate becomes difficult. It is more preferably 70 × 10 ⁻⁷ to 80 × 10 ⁻⁷ / ° C. The average linear expansion coefficient α of the glass substrate at 50 to 350 ° C. is typically 65 × 10 ^{−7 to} 90 × 10 ⁻⁷ / ° C.
Is. It is more preferable that the glass of the present invention has T _S of 450 to 650 ° C. and α of 65 × 10 ^{−7 to} 85 × 10 ⁻⁷ / ° C.

Next, the composition of the glass of the present invention will be described with mol% simply referred to as%. SiO ₂ is a glass network former and is essential. If it is less than 10%, the chemical durability is lowered. It is preferably at least 15%. If it exceeds 40%, T _S becomes high. It is preferably 35% or less.

B ₂ O ₃ is a glass network former and a component for suppressing silver diffusion, and is essential. If it is less than 20%, silver tends to diffuse, and when the glass of the present invention is used for the back surface dielectric, the amount of silver that diffuses through the back surface dielectric from the silver electrode and reaches the partition wall increases, and silver colloid is formed in the partition wall. It is easy to generate, that is, the partition walls are easily yellowed. If it exceeds 45%, the chemical durability is lowered. It is preferably 43% or less.

PbO is a component that lowers T _S or a component that stabilizes glass and is essential. If it is less than 1%, T _S becomes high. It is preferably 10% or more, more preferably 20% or more. If it exceeds 60%, T _S tends to be too low. Preferably 50% or less, more preferably 40%
The ratio is particularly preferably 35% or less.

Al ₂ O ₃ , TiO ₂ and ZrO ₂ are components for increasing chemical durability, and at least one of them is used.
Must contain seeds. If the total content of these three components, Al ₂ O ₃ + TiO ₂ + ZrO _2, is less than 1%, the chemical durability decreases. It is preferably at least 2%. 25
If it exceeds%, T _S becomes high. It is preferably 20% or less, more preferably 10% or less. The content of Al ₂ O ₃ is 2
It is preferably from 10%.

MgO, CaO, SrO, BaO and Z
nO is a component that enhances chemical durability or a component that stabilizes glass, and must contain at least one of them. The total content of these 5 components MgO
If + CaO + SrO + BaO + ZnO is less than 4%, the chemical durability is lowered or the glass becomes unstable. It is preferably at least 4.5%, particularly preferably at least 5%.
If it exceeds 20%, the glass becomes rather unstable. It is preferably 15% or less. The content of BaO is preferably 4 to 15%. It is more preferably 4.5% or more, and particularly preferably 5% or more.

CeO ₂ and CuO are components that suppress the formation of silver colloid, and thus the yellowing, and are essential. The total content of CeO ₂ and CuO _CeO 2 +
If the content of CuO is less than 0.1%, yellowing occurs. Preferably 0.2%
The above is more preferably 0.25% or more, and particularly preferably 0.35% or more. If it exceeds 1%, the glass is deeply colored. Preferably 0.8% or less, more preferably 0.75
% Or less. It is preferable to contain CeO ₂ .

The glass of the present invention consists essentially of the above components, but may contain other components within the range not impairing the object of the present invention. The total content of the other components is 5
% Or less is preferable. As the other components, rare earth oxides such as La ₂ O ₃ , P ₂ O ₅ , MnO,
Fe ₂ O ₃ , CoO, NiO, GeO ₂ , Y ₂ O ₃ , M
oO ₃ , Rh ₂ O ₃ , Ag ₂ O, In ₂ O ₃ , Te
O ₂ , WO ₃ , ReO ₂ , Bi ₂ O ₃ , V ₂ O ₅ , Pd
O and CuO are exemplified.

The glass of the present invention has a SiO ₂ content of 15 to 35.
_Mol%, B 2 _{O 3} is 20 to 43 mol%, PbO is 20
35 mol%, Al ₂ O ₃ + TiO ₂ + ZrO ₂ is 2% or more, Al ₂ O ₃ is 2 to 10 mol%, BaO is 4 to 15 mol%, CeO ₂ + CuO is 0.25 to 0.75 mol%. Preferably there is.

The glass-ceramic composition of the present invention is suitable for producing a back surface dielectric when it is particularly desired to suppress or prevent erroneous discharge of plasma discharge in a cell. Next, the components and composition of the glass-ceramic composition of the present invention will be described using mass percentage notation. The glass powder of the present invention is a fixing material. The content is preferably 50% or more. If it is less than 50%, the sinterability is lowered. It is more preferably 70% or more, and particularly preferably 80% or more.

The ceramics filler is a component that suppresses or prevents charging of the back surface dielectric which causes erroneous discharge in the cell. The content is preferably 10% or more. If it is less than 10%, the effect of suppressing or preventing the charging is small. It is more preferably at least 15%.

The ceramic filler is alumina, mullite, zircon, zirconia, cordierite, aluminum titanate, β-spodumene, α-quartz, quartz glass, β from the viewpoint of easy handling or availability.
It is preferably powder of one or more ceramics selected from the group consisting of quartz solid solution, β-eucryptite and titanium oxide. The glass-ceramic composition of the present invention consists essentially of the above components, but may contain other components as long as the object of the present invention is not impaired. The total content of the other components is preferably 10% or less, more preferably 5% or less.

Next, the plasma display panel rear substrate of the present invention (hereinafter simply referred to as the substrate of the present invention) will be described with reference to FIG. FIG. 1 is a diagram for explaining the substrate of the present invention, and shows a schematic outline of a part of the cross section of the substrate of the present invention. Reference numeral 10 is a substrate of the present invention, 1 is a glass substrate, 2 is an address electrode, 3 is a back dielectric, and 4 is a partition. The phosphor layer formed on the partition wall is not shown.

The glass substrate 1 is usually SiO ₂ --Al ₂ O.
₃ consists -CaO-SrO-Na ₂ O-based glass or soda lime silica glass, the α is 65 × ^{10 -7} ~
90 × 10 ⁻⁷ / ° C., and its T _S is 700 to 850 ° C. The thickness of the glass substrate 1 is 2.5 to 3.0 mm.

The address electrode 2 is usually a silver electrode. Typically, the thickness is 7 μm, the line width is 80 μm, and the pitch is 300 μm. The address electrode 2 is, for example,
The silver paste is printed on the glass substrate 1 by a screen printing method and baking.

The back surface dielectric 3 covers the address electrodes 2 to protect the address electrodes 2.
Formed on. In addition, the rear surface dielectric 3 is usually formed on the portion of the glass substrate 1 where the address electrodes 2 are not formed.
Is formed. The thickness of the back dielectric 3 is typically 10
Is about 15 μm. If the thickness is less than 10 μm, the address electrode 2 may not be protected.

The backside dielectric 3 is usually made of glass such as lead borosilicate glass. When it is desired to particularly suppress or prevent charging of the back surface dielectric 3 or to increase the reflectance of the back surface dielectric 3, the back surface dielectric 3 may contain an appropriate ceramic filler in addition to the glass. . The back surface dielectric 3 is preferably produced by firing the glass of the present invention or the glass ceramic composition of the present invention.

The back surface dielectric 3 contains at least one of CeO ₂ and CuO. If neither of these is included, when the address electrode 2 is a silver electrode, colloidal generation of silver diffused from the silver electrode to the back surface dielectric 3 becomes remarkable, and the back surface dielectric 3 remarkably turns yellow.

The total content of CeO ₂ and CuO in the back surface dielectric 3 is preferably 0.25 mol% or more. If it is less than 0.25 mol%, the back surface dielectric 3 may be significantly yellowed. It is more preferably 0.35 mol% or more, and particularly preferably 0.4 mol% or more. Moreover, it is preferable that the said total is 0.75 mol% or less.
If it exceeds 0.75 mol%, the glass itself may be strongly colored. It is more preferably 0.7 mol% or less.

It is particularly preferred that the backside dielectric 3 contains CeO ₂ . The CeO ₂ content in the back surface dielectric 3 is more preferably 0.1 mol% or more, and particularly preferably 0.2.
It is at least mol%. Also, the CeO ₂ content is 0.7.
It is preferably 5 mol% or less. It is more preferably 0.7 mol% or less.

The partition wall 4 is formed on the back surface dielectric 3 as a wall of the cell for generating the plasma discharge. Typically, the width (wall thickness) of the partition wall 4 is 5
The height is 0 μm, the height is 100 μm, and the pitch is 300 μm.

The partition wall 4 is usually manufactured as follows. That is, a glass ceramics composition for partition walls containing a low-melting glass powder such as lead borosilicate glass powder and a ceramics filler is applied on the rear surface dielectric 3 and then dried, and a dry film is laminated thereon to expose a desired pattern. To do. After that, development is performed, sand blasting is performed, the dry film photosensitive portion is peeled and removed, and then baking is performed.

A phosphor layer (not shown) is formed on the partition wall 4 by applying a phosphor for emitting light by the plasma discharge.

[0035]

[Examples] In the column of SiO ₂ to CuO in Table 1, mol%
Mix and mix the raw materials so that the composition shown in
It melted for 1 hour using a platinum crucible in an electric furnace at 0 to 1350 ° C. to obtain molten glass. The obtained molten glass was poured out to obtain flake-shaped glass, and the flake-shaped glass was crushed with a ball mill to obtain glass powder having an average particle diameter of 2 μm.

The glass transition points T _G (unit: ° C.), softening point T _S (unit: ° C.) and α of the obtained glass powders A to _G
(Unit: 10 ⁻⁷ / ° C.) is shown in Table 1. Note that α was measured as follows. That is, a glass powder was pressure-molded and fired at 600 ° C. for 10 minutes to obtain a fired body, and the fired body was processed into a cylindrical shape having a diameter of 5 mm and a length of 20 mm by using a differential thermal expansion meter. It was measured.

Next, these glass powders and titania powders were prepared and mixed in the glass and filler columns of Table 2 in the proportions shown in the mass percentages, respectively, to prepare back dielectric powder mixtures (Examples 1 to 8). ). The glass powder used is shown in the column of glass type. In addition, the titania powder was not used in Examples 2, 3, and 8.

On the other hand, a solvent was prepared by mixing terpineol, butyl carbitol acetate, and 2,2,4-trimethyl 1,3-pentanediol monoisobutyrate in a mass ratio of 1: 1: 1. The solvent and ethyl cellulose were mixed at a mass ratio of 88:12 to prepare a vehicle. The back dielectric powder mixture and the vehicle were kneaded so that the mass ratio was 80:20 to prepare a back dielectric paste.

Further, glass powder E, fused silica powder, α-
A mass ratio of quartz powder and alumina powder is 86.3: 4.7:
2.9: 6.1 were mixed and mixed to prepare a partition wall powder mixture. The partition wall powder mixture and the vehicle were kneaded in a mass ratio of 82:18 to prepare a partition wall paste. The fired body obtained by firing the partition wall paste had a relative dielectric constant of 9.

Next, using the back dielectric paste and the partition paste, a simulated PDP back substrate was prepared as described below. This simulated product differs from the PDP back substrate in that the portion corresponding to the partition wall is solid.

SiO of 75 mm × 50 mm × 3 mm_Two−
Al_TwoO_Three-CaO-SrO-Na _TwoO-type glass (Asahi Glass
Line width 50μ on the glass substrate made by PD200)
m, pitch 250 μm, silver electrode is formed, and electrode forming substrate
And Paste the back dielectric paste on this electrode-formed substrate.
Screen-print in a solid state, dry, and then at 580 ℃ for 15 minutes
Then, the back dielectric was formed on the electrode forming substrate. Na
The back dielectric paste has a back dielectric thickness of 10μ.
Screen-printing was performed so as to obtain m.

Next, a paste for barrier ribs is blade-coated on half of the upper surface of the back dielectric, dried and baked at 580 ° C. for 15 minutes to form a layer corresponding to the barrier on the back dielectric. Formed on. The partition paste is
Blade coating was performed so that the thickness of the layer corresponding to the partition wall was 100 μm.

With respect to the simulated PDP back substrate thus obtained, the degree of yellowing of the back dielectric without the layer corresponding to the partition and the layer corresponding to the partition was evaluated as follows. .

A spectrophotometer (U-3500: manufactured by Hitachi, Ltd.) was used to measure the reflection spectra of the layers corresponding to the back surface dielectric and the partition wall using an integrating sphere. b was calculated. b = 200 × [(Y /
99.998) ¹ / 3- (Z / 118.22)
5) ^1/3 ] Here, as Y and Z, JIS Z8
722-1994, “Appendix 1.1.6 Tristimulus value X,
Weighting coefficient for calculating Y and Z (380- (5) -7
80, C) "and Y and Z described in".

It is preferable that both b (hereinafter referred to as b ₁ ) in the back surface dielectric and b (hereinafter referred to as b ₂ ) in the layer corresponding to the partition wall are 4.0 or less.
If it exceeds 4.0, yellowing may be strong, that is, yellowing may be remarkable. It is more preferably 3.0 or less.

Further, it is preferable that both b ₁ and b ₂ are -10 or more. If it is less than −10, the blue tint may be strong.

[0047]

[Table 1]

[0048]

[Table 2]

[0049]

According to the present invention, it is possible to obtain a plasma display panel rear substrate with less yellowing of the rear dielectric and partition walls.

[Brief description of drawings]

FIG. 1 is a cross-sectional (partial) schematic view of a plasma display panel rear substrate of the present invention.

[Explanation of symbols]

1: Glass substrate 2: Address electrode 3: Backside dielectric 4: Partition wall 10: Plasma display panel rear substrate

Continued front page    F-term (reference) 4G062 AA01 AA15 BB01 BB04 DA04                       DA05 DB01 DB02 DB03 DB04                       DC04 DC05 DD01 DE01 DE02                       DE03 DE04 DF03 DF04 DF05                       DF06 EA01 EA10 EB01 EC01                       ED01 ED02 ED03 ED04 EE01                       EE02 EE03 EE04 EF01 EF02                       EF03 EF04 EG01 EG02 EG03                       EG04 FA01 FA10 FB01 FB02                       FB03 FB04 FC01 FC02 FC03                       FC04 FD01 FE01 FF01 FG01                       FH01 FJ01 FK01 FL01 FL02                       GA01 GA10 GB01 GC01 GD01                       GE01 HH01 HH03 HH04 HH05                       HH07 HH09 HH11 HH13 HH15                       HH17 HH20 JJ01 JJ03 JJ05                       JJ07 JJ10 KK01 KK03 KK05                       KK07 KK10 MM25 NN32 NN40                       PP00                 5C040 FA01 FA04 GB14 GD07 KA08                       KA10 MA12

Claims (8)

[Claims] 1. A essentially by mole% based on the following _{oxides, SiO 2 10~40%, B 2} O 3 20~45%, PbO 1~60%, Al 2 O 3 + TiO 2 + ZrO 2 1~ 25%, MgO + CaO + SrO + BaO + ZnO 4-20%, CeO ₂ + CuO 0.1-1%, a low melting point glass. 2. SiO ₂ is 15 to 35% in terms of mol%,
B ₂ O ₃ is 20 to 43%, PbO is 20 to 35%, Al
The low content according to claim 1, wherein ₂ O ₃ + TiO ₂ + ZrO ₂ is 2% or more, Al ₂ O ₃ is 2 to 10%, BaO is 4 to 15%, and CeO ₂ + CuO is 0.25 to 0.75%. Melting point glass. 3. A softening point of 450 to 650 ° C., 50 to
Average linear expansion coefficient at 350 ° C. is 65 × 10 ⁻⁷ to 8
The low melting point glass according to claim 1, which has a temperature of 5 × 10 ⁻⁷ / ° C. 4. 4. A ceramics filler and claims 1 and 2.
Alternatively, a glass-ceramic composition consisting essentially of the powder of the low-melting glass described in 3 above. 5. An address electrode is formed on a glass substrate,
A rear substrate of a plasma display panel, wherein the address electrode is covered with a dielectric layer containing at least one of CeO ₂ and CuO, and partition walls are formed on the dielectric layer. 6. The rear panel of the plasma display panel according to claim 5, wherein the total content of CeO ₂ and CuO in the dielectric layer is 0.25 to 0.75 mol%. 7. The plasma display according to claim 5, wherein the dielectric layer is obtained by firing the powder of the low melting point glass according to claim 1, 2 or 3. Panel back substrate. 8. The rear substrate of the plasma display panel according to claim 5, wherein the dielectric layer is obtained by firing the glass ceramic composition according to claim 4.