JP2005336048A - Glass composition, paste composition, and plasma display panel - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a glass composition that is lead-free, and that, when used as a dielectric layer or the like of a PDP, suppresses coloration of a dielectric layer, a transparent conductive film and a glass substrate, and suppresses reduction in transmittance of the dielectric layer. <P>SOLUTION: The glass composition used for forming the dielectric layer 6 includes, by weight, 0.1-20% GeO<SB>2</SB>, 3-35% B<SB>2</SB>O<SB>3</SB>, 4-45% ZnO, 10-80% Bi<SB>2</SB>O<SB>3</SB>, and ≤0.5% SiO<SB>2</SB>and is free of PbO. It is preferable to further incorporate ≤8 wt% Al<SB>2</SB>O<SB>3</SB>and ≤20 wt% of at least one species selected from the group consisting of MgO, CaO, SrO, and BaO into the glass composition. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a glass composition, and more particularly, to a glass composition used for forming a dielectric layer of a plasma display panel.

As a flat display, a plasma display panel (hereinafter referred to as PDP) has been attracting attention.
The PDP has a front plate in which a display electrode, a dielectric layer, and a dielectric protective layer are formed on a front glass substrate, and an address electrode, a dielectric layer, a dielectric layer, a partition, and a phosphor layer are formed on a rear glass substrate. The rear plate thus formed is bonded together.

In this PDP, the dielectric layer is desired to have various properties such as having a sufficient withstand voltage, having high transparency, and having a firing temperature as low as possible (specifically, capable of firing at 600 ° C. or lower). It is made of melting point glass.
As this low-melting glass, a lead glass containing PbO as a main component including a glass composition based on SiO ₂ —B ₂ O ₃ —PbO is widely used (see Patent Document 1).
Japanese Patent Laid-Open No. 3-170346 JP 2002-53342 A JP-A-9-278482

However, it has been pointed out that lead is toxic to humans and harmful to the environment, and the influence of lead on the environment is regarded as a problem when PDP is manufactured or disposed of. Therefore, it is required to use a glass composition that does not contain lead in the dielectric layer.
Based on this background, as a dielectric glass composition containing no lead, bismuth glass (see Patent Document 2) containing Bi ₂ O ₃ and does not include any PbO and Bi ₂ O ₃ B ₂ O ₃ —ZnO-based glass (see Patent Document 3) has been proposed.

However, when B ₂ O ₃ —ZnO-based glass is used for the dielectric layer, the dielectric layer, the transparent conductive film, or the glass substrate may be colored, or the display characteristics of the PDP may deteriorate. This is because the conventional B ₂ O ₃ —ZnO-based glass contains an alkali metal oxide in order to lower the softening point, and the alkali metal is in contact with the metal contained in the electrode at the contact interface with the electrode. This is because the coloration or the withstand voltage is reduced by reacting between them.

In addition, when bismuth-based glass containing Bi ₂ O ₃ is used for the dielectric layer, the transmittance of the dielectric layer is lowered, so that the brightness of the PDP may be lowered or the display characteristics may be adversely affected. The cause is that bismuth-based glass often contains SiO _{2 in} order to obtain a stable amorphous glass at the time of glass production. In the manufacturing process of PDP, firing is performed when a dielectric layer is formed. Since a plurality of heat treatments are repeated, Bi—Si—O-based microcrystals such as bismuth silicate are precipitated in the glass of the dielectric layer, and the light transmitted through the dielectric layer is scattered by the microcrystals. It is to be done.

  In order to solve the problem, the present invention does not contain lead in a glass composition, and when used for a dielectric layer of a PDP or the like, the dielectric layer, the transparent conductive film or the glass substrate is hardly colored, An object of the present invention is to provide a dielectric layer in which the transmittance of the dielectric layer is not easily lowered, thereby realizing a PDP having excellent display characteristics.

In order to achieve the above object, the glass composition according to the present invention comprises GeO _{2 in an amount} of 0.1 to 20% by weight, B ₂ O ₃ in an amount of ₃ to 35% by weight, ZnO in an amount of 4 to 45% by weight, Bi _2. It was decided to contain 10 to 80% by weight of O ₃ .
Alternatively, GeO ₂ is contained in an amount of 0.1 to 20% by weight, B ₂ O _{3 in an amount} of ₃ to 20% by weight, ZnO in an amount of 4 to 30% by weight, and Bi ₂ O _{3 in an amount} of 40 to 80% by weight.

Alternatively, GeO ₂ is contained in an amount of 0.1 to 20% by weight, B ₂ O ₃ in an amount of 12 to 35% by weight, ZnO in an amount of 15 to 45% by weight, and Bi ₂ O _{3 in an amount} of 10 to 40% by weight.
The glass composition may further contain Al ₂ O ₃ . However, the content is 8% by weight or less.
The glass composition may further contain 20% by weight or less of at least one selected from MgO, CaO, SrO and BaO.

In the paste composition according to the present invention, the glass composition having the above composition, the binder resin and the solvent were included.
In the present invention, in a PDP in which an electrode and a dielectric layer covering the electrode are disposed on a surface facing the discharge space, the dielectric layer is formed of the glass composition.
According to the present invention, in the PDP in which the electrode, the first dielectric layer covering the electrode, and the second dielectric layer covering the first dielectric layer are disposed on the surface facing the discharge space, Of the dielectric layer and the second dielectric layer, at least the first dielectric is formed of the glass composition. Here, the second dielectric layer may be formed of a SiO ₂ —B ₂ O ₃ —ZnO-based glass composition.

  The softening point of the glass composition contained in the first dielectric layer is preferably higher than the softening point of the glass composition contained in the second dielectric layer.

According to the present invention, Bi ₂ O ₃ is contained in an amount of 10 to 80% by weight, alternatively 40 to 80% by weight, or alternatively 10 to 40% by weight, and this Bi ₂ O ₃ serves to lower the softening point. Therefore, the softening point can be lowered even if PbO is not included.
In addition, as described above, bismuth-based glass generally contains SiO _{2 in} order to obtain a stable amorphous glass during glass production, but the glass composition of the present invention contains GeO _2. This GeO ₂ has a function of forming a glass-structured network and maintaining the amorphous state stably.

Accordingly, even if the SiO ₂ content in the glass composition is 0.5% by weight or less or no SiO ₂ is contained, an amorphous glass that is stable during glass production can be obtained.
Therefore, according to the present invention, a glass composition having a low softening point can be obtained without containing lead, and when used in a dielectric layer, the dielectric layer, the transparent conductive film and the glass substrate are hardly colored, and the dielectric A layer in which the transmittance of the layer is hardly lowered is obtained.

[Composition of glass composition]
The glass composition according to the present invention is a bismuth-based glass composition, basically containing no PbO, 0.1 to 20% by weight of GeO ₂ , ₃ to 35% by weight of B ₂ O ₃ , ZnO. In an amount of 4 to 45% by weight and Bi ₂ O _{3 in an amount} of 10 to 80% by weight.
The phrase “basically does not contain PbO” means that “a very small amount of lead that does not affect the characteristics may be included because it is difficult to completely remove Pb industrially”.

Here, the range of the content of Bi ₂ O ₃ , GeO ₂ , B ₂ O ₃ , and ZnO is set to the range shown in the following embodiment 1 in the above range, or shown in the following embodiment 2. It is preferable to set the range.
[Embodiment 1]
The glass composition according to Embodiment 1 does not contain PbO, contains GeO _{2 in an amount} of 0.1 to 20% by weight, B ₂ O _{3 in an amount} of ₃ to 20% by weight, ZnO in an amount of 4 to 30% by weight, and Bi ₂ O _3. 40 to 80% by weight.

The function of each component contained in the glass composition is as follows.
GeO ₂ is a component having a function of forming a network having a glass structure, and has a function of maintaining the amorphous state more stably. In order to obtain this effect, the GeO ₂ content needs to be 0.1% by weight or more. On the other hand, since the content of GeO ₂ exceeds 20 wt% GeO ₂ begins to precipitate in the glass be 20 wt% or less preferred.

B ₂ O ₃ has a function of forming a glass-structured network like GeO ₂ . The content of B ₂ O ₃ is preferably 3% by weight or more in order to obtain amorphous glass, but if it exceeds 20% by weight, the glass tends to be devitrified, so that the content is 20% by weight or less. Is preferred.
ZnO has a function of improving chemical durability in a bismuth-based glass while suppressing an increase in the softening point of the glass.

The ZnO content is preferably 4% by weight or more in order to obtain the effect. However, when the ZnO content is increased, the glass is devitrified, so it is preferably 30% by weight or less.
Bi ₂ O ₃ is a main component for realizing a low softening point.
In general, the glass composition used for the dielectric layer of the PDP is required to have a softening point of 600 ° C. or lower. For this purpose, the Bi ₂ O ₃ content is preferably 40% by weight or more. . However, if the content of Bi ₂ O ₃ exceeds 80% by weight, the glass becomes unstable and devitrifies, so that it is preferably 80% by weight or less.

[Embodiment 2]
The glass composition according to Embodiment 2 does not contain PbO, contains GeO _{2 in an amount} of 0.1 to 20% by weight, B ₂ O ₃ in an amount of 12 to 35% by weight, ZnO in an amount of 15 to 45% by weight, and Bi ₂ O _3. 10 to 40% by weight.
Although the function of each component contained in the glass composition is as described in the first embodiment, the present embodiment has the following features and effects as compared with the first embodiment.

In the first embodiment, the content of Bi ₂ O ₃ is 40% by weight or more, whereas in the second embodiment, the content of Bi ₂ O ₃ is set as low as 40% by weight or less. The effect of reducing the softening point by Bi ₂ O ₃ is smaller than 1, but the B ₂ O ₃ content is set to 12% by weight or more and the ZnO content is set to 15% by weight or more. Many effects of reducing the softening point due to ₂ O ₃ and ZnO can be obtained. Therefore, also in this embodiment, it is possible to suppress the softening point of the glass composition to 600 ° C. or less.

However, if the content of Bi ₂ O ₃ is less than 10% by weight, the softening point cannot be suppressed to 600 ° C. or less, so that it is preferably 10% by weight or more.
Further, if the content of B ₂ O ₃ exceeds 35% by weight, the coefficient of thermal expansion becomes smaller than the preferred range (65 × 10 ^{−7 to} 85 × 10 ⁻⁷ / ° C.). Is preferred. Further, if the ZnO content exceeds 45% by weight, it becomes difficult to obtain an amorphous glass. Therefore, the content is preferably 45% by weight or less.

In the bismuth-based glass, the component that greatly contributes to the relative dielectric constant is Bi ₂ O _{3. When} the Bi ₂ O ₃ content is lowered, the relative dielectric constant is lowered. In the present embodiment, the Bi ₂ O ₃ content is 40% by weight or less, which is lower than that of the first embodiment. Therefore, the relative dielectric constant of the glass is lowered, and the relative dielectric constant can be 11.5 or less.
Therefore, if the glass of this embodiment is used for the dielectric layer of PDP, the effect of reducing power consumption is great.

(Effects of the glass composition of the present invention)
According to the glass composition of the above embodiments 1, 2, Bi ₂ O ₃ are contained in the range of 10 to 80 wt%, the Bi ₂ O ₃ is serves to lower the softening point of the glass composition Therefore, even if PbO is not contained, a low softening point can be obtained.
In addition, in the B ₂ O ₃ —ZnO-based glass, an alkali metal oxide was included in order to obtain a low softening point. In that case, at the interface where the alkali metal is in contact with the electrode, between the metal contained in the electrode. The reaction may cause coloration or decrease in withstand voltage. On the other hand, according to the glass composition of Embodiment 1, 2, it can be set as a low softening point even if it does not contain an alkali metal oxide. Therefore, in the glass composition of the present embodiment, the content of the alkali metal oxide can be kept low, whereby the alkali metal oxide does not react with the electrode even when used for the dielectric layer in contact with the electrode. Less likely to occur.

In general, bismuth-based glass is less stable as amorphous compared to lead glass, and it is difficult to obtain amorphous during glass production. SiO ₂ is contained in the glass, but in this case, the crystal tends to precipitate in the glass by the subsequent heat treatment. In particular, Bi ₂ O ₃ and SiO ₂ are present in the glass, so that bismuth silicate and the like are present. Microcrystals may precipitate out. In the PDP dielectric layer, if a large number of crystals having a size of several μm or more are deposited, the transmitted light is scattered, so that sufficient display characteristics cannot be obtained.

On the other hand, in the glass composition of the present embodiment, GeO ₂ that functions to form a glass structure network is included instead of SiO ₂ , so the content of SiO ₂ in the glass composition is reduced to 0. Even if it is set to 5% by weight or less, a network having a glass structure is formed. Further, GeO ₂ is less likely to precipitate microcrystals than SiO ₂ . Accordingly, a stable amorphous glass can be obtained with very little crystal precipitation during glass production and heat treatment.

As will be described in detail later, when the glass composition of the present embodiment is used for the dielectric layer of the PDP, a PDP having excellent display characteristics can be obtained without containing lead in the dielectric layer.
In the said glass composition, it is preferable to make it further as follows.
The glass composition according to this embodiment preferably further contains Al ₂ O ₃ . This Al ₂ O ₃ is not an essential component, but the stability of the amorphous glass can be improved by adding a small amount.

However, when the content of Al ₂ O ₃ exceeds 8% by weight, the glass is devitrified. Therefore, the content is preferably 8% by weight or less.
In the glass composition according to this embodiment, one or more oxides selected from MgO, CaO, SrO, and BaO may be included.
Oxides such as MgO, CaO, SrO, and BaO have a function of helping the formation of a network having a glass structure, and the amorphous state can be stably maintained by appropriately adding the oxide. However, if the content of these oxides exceeds 20% by weight, the glass becomes unstable and tends to crystallize, so it is preferably 20% by weight or less.

In addition to the above, in order to modify the glass, various components can be appropriately added as long as the effects of the present invention are not impaired.
For example, a small amount of alkali metal oxide may be contained as long as it does not impair the dielectric strength of the dielectric layer and does not cause side effects such as discoloration.
In general, when manufacturing a PDP, a dielectric layer is formed on a substrate glass by applying a dielectric glass composition on the substrate glass and softening it by a thermal process. However, since the thermal expansion coefficient of the high strain point glass widely used as the substrate glass is 80 × 10 ⁻⁷ / ° C. to 90 × 10 ⁻⁷ / ° C., the residual between the substrate glass and the dielectric layer. In order to reduce the stress, it is preferable that the glass composition used for the dielectric layer has a thermal expansion coefficient in the range of 65 × 10 ⁻⁷ / ° C. to 85 × 10 ⁻⁷ / ° C.

[Paste composition]
The paste composition according to the present invention includes the glass composition of Embodiments 1 and 2 described above, a binder resin, and a solvent.
The content is preferably 30 to 90% by weight of the glass composition, 1 to 10% by weight of the binder resin, and 10 to 80% by weight of the solvent. Further, the glass composition is preferably used as a powder having an average particle diameter D50 of 0.1 μm to 3 μm as measured by a laser diffraction method.

Preferable binder resins include cellulose resins such as nitrocellulose, ethyl cellulose, and hydroxyethyl cellulose, acrylic resins and copolymers such as polybutyl acrylate and polymethacrylate, polyvinyl alcohol, and polyvinyl butyral.
Preferred solvents include terpenes such as α-, β-, and γ-terpineol, ethylene glycol monoalkyl ethers, ethylene glycol dialkyl ethers, diethylene glycol monoalkyl ethers, diethylene glycol dialkyl ethers, ethylene glycol monoalkyl ether acetates. , Ethylene glycol dialkyl ether acetates, diethylene glycol monoalkyl ether acetates, diethylene glycol dialkyl ether acetates, propylene glycol monoalkyl ethers, propylene glycol dialkyl ethers, propylene glycol monoalkyl ether acetates, propylene glycol dialkyl ether acetates, methanol , Ethanol, isop Propanol, it may be mentioned alcohols such as 1-butanol.

In addition, you may mix suitably the additives, such as an inorganic material powder, a plasticizer, and a dispersing agent, with the paste composition of this embodiment.
[Application of PDP to dielectric layer]
FIG. 3 is a partial cross-sectional perspective view showing the main configuration of the PDP according to the present embodiment. FIG. 1 is a cross-sectional view of this PDP.

This PDP is an AC surface discharge type, and has the same configuration as the conventional PDP except that the dielectric layer is formed of the glass composition described above.
This PDP is configured by bonding a front plate 1 and a back plate 8 together. The front plate 1 includes a front glass substrate 2, a display electrode 5 composed of a transparent conductive film 3 and a bus electrode 4 formed on an inner side surface (a surface facing the discharge space 14), and a dielectric layer 6 that covers the display electrode 5. And a dielectric protective layer 7 made of magnesium oxide. A material made of the glass composition described above is used for the dielectric layer 6.

  The back plate 8 includes a back glass substrate 9, an address electrode 10 formed on one side thereof, a dielectric layer 11 covering the address electrode 10, a partition wall 12 provided on the top surface of the dielectric layer 11, and a partition wall 12. And a phosphor layer formed between them. The phosphor layer is formed by sequentially arranging a red phosphor layer 13 (R), a green phosphor layer 13 (G), and a blue phosphor layer 13 (B).

The front plate 1 and the back plate 8 are arranged so that the longitudinal directions of the display electrodes 5 and the address electrodes 10 are orthogonal to each other, and are bonded using a sealing member (not shown). The display electrode 5 is formed by laminating a bus electrode 4 made of Ag, Al or Cr / Cu / Cr on a transparent conductive film 3 made of ITO or tin oxide in order to ensure good conductivity.
The display electrode 5 and the address electrode 10 are each connected to an external drive circuit (not shown), and a discharge is generated in the discharge space 14 by a voltage applied from the drive circuit, and a short wavelength (wavelength generated by the discharge). The phosphor layer 13 is excited by ultraviolet rays of 147 nm and emits visible light.

According to such a PDP, since the dielectric layer 6 does not contain lead and the content of alkali metal is small, the metal (for example, Ag, Al, Cu) in which the alkali metal is contained in the bus electrode 4, By reacting with Sn contained in the transparent conductive film 3, the front plate 1 is not colored, and the withstand voltage of the dielectric layer 6 is not lowered.
The dielectric layer 6 can be formed by applying and baking the glass paste.

More specifically, the paste composition is typically applied by a screen method, a bar coater, a roll coater, a die coater, a doctor blade or the like, and baked. However, without being limited thereto, for example, it can be formed by a method of attaching and baking a sheet containing the glass composition.
The film thickness of the dielectric layer 6 is preferably 50 μm or less in order to ensure light transmission.

Next, an example in which the glass composition of the present invention is used for a PDP having a dielectric layer having a two-layer structure as shown in FIG. 2 will be described.
The PDP shown in FIG. 2 is the same as the PDP in FIG. 1 except that the PDP shown in FIG. 2 has a two-layer structure of a first dielectric layer 15 and a second dielectric layer 16 instead of the dielectric layer 6.
As shown in FIG. 2, the first dielectric layer 15 covers the transparent conductive film 3 and the bus electrode 4, and the second dielectric layer 16 is disposed so as to cover the first dielectric layer 15. Yes.

When the dielectric layer has a two-layer structure as described above, the glass composition of the present invention is used for the first dielectric layer 15. Thereby, at least the first dielectric layer 15 does not have a decrease in transmittance due to crystal precipitation and does not contain lead.
Even if glass having a high alkali metal content is used for the second dielectric layer 16, the content of the alkali metal in the first dielectric layer 15 in direct contact with the electrodes 3 and 4 is small. Is prevented from being colored or the dielectric strength of the dielectric layer from being lowered.

Therefore, the glass composition of the present invention may be used for the second dielectric layer 16, and another glass composition may be used for the second dielectric layer 16.
However, if the glass composition of the present invention is used for both the first dielectric layer 15 and the second dielectric layer 16, the transmittance of the entire dielectric layer is not reduced due to crystal precipitation, and the reliability of the PDP is also improved. Get higher.

On the other hand, in the case of using a SiO ₂ -B ₂ O ₃ -ZnO based glass composition on the second dielectric layer 16, the SiO ₂ -B ₂ O ₃ -ZnO based glass, from lead glass and bismuth glass The relative dielectric constant is low (the relative dielectric constants at room temperature and 1 MHz are generally lead glass: 10-15, bismuth glass: 8-13, SiO ₂ —B ₂ O ₃ —ZnO glass: 5-9. ). Therefore, the power consumption of the PDP can be reduced by using the SiO ₂ —B ₂ O ₃ —ZnO-based glass composition for the second dielectric layer 16.

When SiO ₂ —B ₂ O ₃ —ZnO-based glass is used, the softening point is set to 600 ° C. or less, and in order to obtain a stable amorphous material that does not crystallize, 5 to 25 wt% SiO ₂ and B ₂ At least one selected from Li ₂ O, Na ₂ O, K ₂ O, and Cs ₂ O, containing 25 to 50 wt% O ₃ , 25 to 60 wt% ZnO, and 6 wt% or less Al ₂ O ₃ Is preferably contained in an amount of 20% by weight or less, and further preferably contains 10% by weight or less of at least one selected from MnO ₂ , CuO and TiO ₂ .

The reason why it is preferable to define the content of each component within the above range is as follows.
SiO ₂ is a component that forms a glass network, and is preferably contained in an amount of 5% by weight or more in order to obtain an effect of stabilizing the glass. However, if it exceeds 25% by weight, the softening point tends to be higher than 600 ° C., which is not preferable.
B ₂ O ₃ has the effect of lowering the softening point while forming a glass network, and is preferably 25% by weight or more. However, if it exceeds 50% by weight, the thermal expansion coefficient becomes small, which is not preferable.

ZnO is preferably contained in an amount of 25% by weight or more in order to stabilize the glass and maintain a low softening point. However, if it exceeds 60% by weight, the glass tends to be devitrified, which is not preferable.
Al ₂ O ₃ is not an essential component, but devitrification of the glass can be prevented by containing a small amount. However, if the content exceeds 6% by weight, the softening point tends to be higher than 600 ° C., which is not preferable.

Li ₂ O, Na ₂ O, K ₂ O, and Cs ₂ O have an effect of lowering the softening point, so it is preferable to contain one or more, but if it exceeds 20% by weight, the thermal expansion coefficient becomes large. It is not preferable.
Since MnO ₂ and CuO have an action of suppressing discoloration due to the reaction between the dielectric layer and the electrode, it is preferable to contain them when discoloration may occur. Moreover, since the relative permittivity can be changed greatly by adding a small amount of TiO ₂ , it is preferable to include it when the relative permittivity needs to be adjusted in the design of the PDP. However, if the content exceeds 10% by weight, devitrification occurs, which is not preferable.

In addition to the above components, in order to adjust the softening point, at least one selected from P ₂ O ₅ , V ₂ O ₅ and TeO ₂ may be further contained. In order to stabilize the amorphous state, at least one selected from MgO, CaO, SrO, and BaO may be included.
Thus, the dielectric layer having a two-layer structure can be formed by forming the first dielectric layer 15 and then applying and baking the glass composition for the second dielectric layer. In this case, it is preferable that the glass composition used for the first dielectric layer 15 has a softening point higher than the softening point of the glass composition contained in the second dielectric layer.

Further, in order to ensure insulation between the electrodes 3 and 4 and the second dielectric layer 16 and prevention of interface reaction, the film thickness of the first dielectric layer 16 is preferably 1 μm or more.
In order to suppress the loss of transmitted light, the total thickness of the first dielectric layer and the second dielectric layer is preferably 50 μm or less.
As described above, by applying the glass composition of the present invention to the dielectric layer of the PDP, the dielectric layer does not contain lead, and the display characteristics are reduced due to discoloration of the dielectric layer and reduction of transmittance. Can be suppressed.

The PDP to which the glass composition according to the present invention is applied is typically a surface discharge type as described above, but is not limited to this and can also be applied to a counter discharge type.
Further, the present invention is not limited to the AC type, and can be applied to a DC type PDP having a dielectric layer.

Examples of the glass composition, glass paste, and PDP of the present invention will be described below, but the present invention is not limited to these examples.
[Example 1] Glass composition and glass paste

表１、表２に示す各組成で、実施例及び比較例にかかるガラス組成物を作製し、これらのガラス組成物を用いてペーストを作製した。
表１に示すＮｏ．１〜４は、実施形態１に相当する実施例であって、ＧｅＯ₂を０．１〜２０重量％、Ｂ₂Ｏ₃を３〜２０重量％、ＺｎＯを４〜３０重量％、Ｂｉ₂Ｏ₃を４０〜８０重量％含有し、ＳｉＯ₂は含有していない。一方、Ｎｏ．５，６は比較例に関するものであって、Ｂ₂Ｏ₃、Ｂｉ₂Ｏ₃、ＳｉＯ₂を含有し、ＧｅＯ₂は含有していない。

With each composition shown in Table 1 and Table 2, glass compositions according to Examples and Comparative Examples were prepared, and pastes were prepared using these glass compositions.
No. shown in Table 1. 1-4 are examples corresponding to Embodiment 1, in which GeO ₂ is 0.1 to 20% by weight, B ₂ O ₃ is ₃ to 20% by weight, ZnO is 4 to 30% by weight, Bi ₂ O. ₃ is contained in an amount of 40 to 80% by weight, and SiO ₂ is not contained. On the other hand, no. Reference numerals 5 and 6 relate to comparative examples, which contain B ₂ O ₃ , Bi ₂ O ₃ and SiO ₂ and do not contain GeO ₂ .

No. shown in Table 2. 11 to 15 are examples corresponding to the second embodiment, in which GeO ₂ is 0.1 to 20% by weight, B ₂ O ₃ is 12 to 35% by weight, ZnO is 15 to 45% by weight, Bi ₂ O. ₃ is contained in an amount of 10 to 40% by weight, and SiO ₂ is not contained or is 0.5% by weight or less.
The specific manufacturing method is demonstrated below.
After weighing and mixing the raw materials of each glass composition, the obtained mixture was put in a platinum crucible and melted at 1100 to 1350 ° C. for 1 hour in an electric furnace. Next, the obtained molten glass was rapidly cooled with a roller to prepare a glass composition, and further pulverized with a ball mill to obtain glass powder having an average particle diameter D50 of 1.5 to 2.2 μm.

  The softening point, thermal expansion coefficient, and dielectric constant of each glass composition obtained were measured. The softening point was obtained from a chart obtained by macro TG-DTA with a glass powder at a heating rate of 10 ° C./min. The thermal expansion coefficient was measured using a thermomechanical analyzer after remelting the glass to form a 4 mm × 4 mm × 20 mm rod. The relative dielectric constant was measured by remelting the glass to form a 50 mm × 50 mm × 3 mm thick plate, depositing an electrode on the surface, and using an LCR meter at a frequency of 1 MHz.

Next, each glass powder obtained was mixed with a vehicle in which ethylcellulose was dissolved in α-terpineol, and paste-formed using three rolls. The paste composition was such that glass powder: 60% by weight, ethyl cellulose: 5% by weight, and α-terpineol: 35% by weight.
For each glass paste, the stability of the glass was measured.

The stability of the glass is obtained by applying a glass paste to a glass substrate by screen printing and heat-treating each softening point for 30 minutes with an optical microscope. The case where the above crystals were precipitated was marked with x.
Tables 1 and 2 show the softening point, the thermal expansion coefficient, the relative dielectric constant, and the glass stability evaluation results.

Regarding the softening point, the glass compositions according to Examples and Comparative Examples all show 600 ° C. or less, and the thermal expansion coefficient is also in the range of 65 × 10 ⁻⁷ / ° C. to 85 × 10 ⁻⁷ / ° C. It was.
Regarding the relative dielectric constant, No. of Example. 1 to 4 and the comparative example are the same level, but No. of the example. As compared with Nos. 1 to 4, the amount of Bi ₂ O ₃ is less. 11 to 15 indicate low values.

Regarding the stability of the glass, all of the examples were o, and all of the comparative examples were x. As a result, since the glass according to the example does not contain SiO ₂ , the glass according to the comparative example is a stable amorphous glass in which crystals are not precipitated by heat treatment, whereas the glass according to the comparative example contains SiO _2. Therefore, crystals are precipitated by heat treatment, indicating that they are unstable.
In Examples 2 to 3 below, examples in which the glass composition of Example 1 is used for a dielectric layer of a PDP will be described.
[Example 2]
First, a paste for forming a transparent conductive film made of ITO is applied on a front glass substrate made of high strain point glass by a screen printing method, and an Ag paste for forming a bus electrode for supplementing conductivity is screened on the top. The display electrodes were formed by applying them by printing and firing them.

  Next, the above No. 3 and no. A dielectric layer was formed by applying a paste composition prepared using the No. 14 glass composition on the upper portion of the display electrode by screen printing and baking. No. No. 3 has a firing temperature of 560 ° C. No. 14 was fired at a firing temperature of 590 ° C. The film thickness of the dielectric layer was 30 μm. A dielectric protective layer made of magnesium oxide was formed on the surface of the dielectric layer by vapor deposition to produce a front plate.

Next, an Ag paste for an electrode was applied in a stripe shape on a back glass substrate made of high strain point glass by screen printing, and baked to form an address electrode. A dielectric layer was formed by applying a paste containing dielectric glass on the address electrodes by screen printing and baking.
Next, the barrier ribs that form the partition of the discharge space are formed in a stripe shape by a photoetching method, and phosphors of three colors of red (R), green (G), and blue (B) are included between the barrier ribs that become the discharge space. Pastes were sequentially applied by a screen printing method, and these were fired to form phosphor layers of each color, thereby producing a back plate.

By applying a paste made of a sealing frit to the peripheral portion of the back plate thus produced by a dispenser, by superimposing the front plate and the back plate so that the display electrodes and the address electrodes are orthogonal, and by firing, The front plate and the back plate were joined.
Next, the end of the glass tube for exhaust was joined to the vent hole provided in the back plate. This joining was performed by applying a paste containing a sealing frit to the opening edge portion of the air hole by an injection method and baking it.

Then, while heating the whole, the internal gas is exhausted through the glass tube, and then the discharge gas is sealed in the discharge space through the glass tube at a predetermined pressure, and then sealed by heating the glass tube. did. Finally, the display electrode and the address electrode were connected to a drive circuit provided outside to complete the PDP.
When the display characteristics of the PDP produced as described above were evaluated by the following method while being lit, it was confirmed that the panel had no discoloration or coloring and had no problems such as a decrease in transmittance.

Panel evaluation method:
The degree of coloration of the panel was measured with a chromaticity meter to evaluate the presence or absence of discoloration. When the dielectric layer changes color due to the reaction with the electrode, or when the dielectric layer itself is colored, the measured value changes.
Further, the PDP was turned on and displayed on the entire surface, and the light emission luminance was measured using a display color analyzer to evaluate the display characteristics. When the transmittance of the dielectric layer is low, the luminance is also low.

Example 3
In this embodiment, the dielectric layer covering the display electrode has a two-layer structure including a first dielectric layer and a second dielectric layer, and the glass composition of the embodiment is formed on the first dielectric layer and the second dielectric layer. Use things.
The manufacturing method will be described below.
A PDP was produced in the same manner as in Example 2 except for the step of forming the dielectric layer of the front plate.

In the step of forming the dielectric layer, no. The paste composition produced using the glass composition of No. 3 was applied and baked at 560 ° C. to form the first dielectric layer. Next, No. 1 is formed on the first dielectric layer. A second dielectric layer was formed by applying a paste composition prepared using the glass composition No. 1 and firing at 545 ° C.
The film thickness of the first dielectric layer was 5 μm, and the film thickness of the second dielectric layer was 25 μm.

When the display characteristics of the completed PDP were evaluated by the method described above, the light emission luminance was good. From this result, it was confirmed that there was no discoloration or coloring in the panel, and there was no problem such as a decrease in transmittance.
Example 4
Also in this example, the dielectric layer covering the display electrode has a two-layer structure composed of the first dielectric layer and the second dielectric layer. The glass composition produced in Example 1 on the first dielectric layer. And a SiO ₂ —B ₂ O ₃ —ZnO-based glass composition is used for the second dielectric layer.

The manufacturing method will be described below.
A PDP was produced in the same manner as in Example 2 except for the step of forming the dielectric layer of the front plate.
In the step of forming the dielectric layer of the front plate, the first dielectric layer was formed in the same manner as in Example 3 above.

Next, a paste composition prepared by using a glass composition (softening point: 545 ° C., relative dielectric constant 6.8) made of SiO ₂ , B ₂ O ₃ , ZnO, Al ₂ O ₃ , K ₂ O is applied. And firing at 550 ° C. to form a second dielectric layer.
The film thickness was 5 μm for the first dielectric layer and 15 μm for the second dielectric layer.
When the display characteristics were evaluated by measuring the light emission luminance while the completed PDP was turned on, the light emission luminance was good. From this result, it was confirmed that there was no discoloration or coloring in the panel, and there was no problem such as a decrease in transmittance.

Luminance measurement and power consumption measurement were performed on the PDPs of Examples 2 to 4 and the PDP according to the comparative example.
The PDP of the comparative example has the above-mentioned No. The dielectric layer was fired at a temperature of 545 ° C. using the glass composition of No. 5, and was produced based on the production method described in Example 2.
The power consumption was measured by displaying each PDP on the entire surface, measuring the voltage applied to the electrode and the discharge current flowing at that time, and calculating the product.

  The results are as shown in Table 3.

なお、表３に示される輝度および消費電力の値は、比較例に関する値を１００とした相対値である。
表３の結果から、実施例２〜４のＰＤＰはいずれも比較例のＰＤＰより輝度が高いことがわかる。

Note that the values of luminance and power consumption shown in Table 3 are relative values with the value relating to the comparative example as 100.
From the results of Table 3, it can be seen that the PDPs of Examples 2 to 4 have higher luminance than the PDP of the comparative example.

  In addition, the glass composition No. 14 and the PDP of Example 4 consume less power than the PDP of the comparative example, and the glass composition No. It can be seen that the power consumption is less than that of the PDP using 3 and the PDP of the third embodiment. This is thought to be because power consumption was reduced because the dielectric constant of the dielectric layer was low (in Example 4, the dielectric constant of the entire dielectric layer was low because the dielectric constant of the second dielectric layer of Example 3 was low). Is also lower.)

As described above, the glass composition according to the present invention can be used as a dielectric layer of PDP as a low-melting glass not containing lead, but besides PDP, adhesion of ceramics, glass and metal, It can also be used for applications such as sealing and coating.
Moreover, it can also be used for paste compositions having various functions. For example, it can be used in place of low-melting glass materials conventionally used in various applications including various parts for electronic devices. Specifically, it can be used for display devices such as various LCR components, semiconductor packages, other electronic components, CRTs, liquid crystal display panels, fluorescent display tubes, and FEDs. Further, it can also be used in tube products for lighting, enamel products, ceramic products and the like.

It is sectional drawing of PDP concerning embodiment. FIG. 2 is a cross-sectional view of the PDP according to the embodiment. It is a fragmentary sectional perspective view of PDP concerning an embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Front plate 2 Front glass substrate 3 Transparent conductive film 4 Bus electrode 5 Display electrode 6 Dielectric layer 7 Dielectric protective layer 8 Back plate 9 Back glass substrate 10 Address electrode 11 Dielectric layer 12 Partition 15 15 1st dielectric layer 16 1st 2 dielectric layers

Claims (20)

GeO ₂ is 0.1 wt% or more and 20 wt% or less,
B ₂ O _{3 in an amount} of 3% by weight to 35% by weight,
ZnO 4 wt% or more, 45 wt% or less,
A glass composition comprising Bi ₂ O _{3 in an amount} of 10 wt% to 80 wt%.   2. The glass composition according to claim 1, further comprising 20% by weight or less of at least one selected from MgO, CaO, SrO and BaO. _2. The glass composition according to claim 1, further comprising Al ₂ O _{3 and} having a content of 8% by weight or less.   The glass composition according to claim 3, further comprising 20% by weight or less of at least one selected from MgO, CaO, SrO and BaO. _2. The glass composition according to claim 1, wherein the content of SiO ₂ is 0.5% by weight or less. GeO ₂ is 0.1 wt% or more and 20 wt% or less,
3 wt% or more and 20 wt% or less of B ₂ O ₃
ZnO 4 wt% or more, 30 wt% or less,
A glass composition comprising Bi ₂ O _{3 in an amount} of 40% by weight to 80% by weight.   The glass composition according to claim 6, further comprising at least one selected from MgO, CaO, SrO and BaO, and the content thereof is 20% by weight or less. Further, Al ₂ include O _3, the glass composition according to claim 6, wherein the content thereof is less than 8 wt%.   The glass composition according to claim 8, further comprising 20% by weight or less of at least one selected from MgO, CaO, SrO and BaO. The glass composition according to claim 6, wherein the content of SiO ₂ is 0.5% by weight or less. GeO ₂ is 0.1 wt% or more and 20 wt% or less,
12 wt% or more and 35 wt% or less of B ₂ O ₃
ZnO 15 wt% or more, 45 wt% or less,
A glass composition comprising Bi ₂ O _{3 in an amount} of 10% by weight to 40% by weight.   The glass composition according to claim 11, further comprising 20% by weight or less of at least one selected from MgO, CaO, SrO, and BaO. The glass composition according to claim 11, further comprising Al ₂ O _{3 and} having a content of 8% by weight or less.   The glass composition according to claim 13, further comprising 20% by weight or less of at least one selected from MgO, CaO, SrO and BaO. The glass composition according to claim 11, wherein the content of SiO ₂ is 0.5% by weight or less. A glass composition according to claim 1;
A paste composition comprising a binder resin and a solvent. A plasma display panel in which an electrode and a dielectric layer covering the electrode are disposed on a surface facing the discharge space,
A plasma display panel, wherein the dielectric layer is made of the glass composition according to claim 1. A plasma display panel in which an electrode, a first dielectric layer covering the electrode, and a second dielectric layer covering the first dielectric layer are disposed on a surface facing the discharge space,
The plasma display panel, wherein at least a first dielectric layer of the first dielectric layer and the second dielectric layer is made of the glass composition according to claim 1. The plasma display panel of claim 18, wherein the second dielectric layer, characterized in that it consists of SiO ₂ -B ₂ O ₃ -ZnO based glass composition. The plasma display panel according to claim 18, wherein the softening point of the glass composition contained in the first dielectric layer is higher than the softening point of the glass composition contained in the second dielectric layer.

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