JP2002145638A - Glass composition and glass forming material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a glass composition of a softening point burning type for suitably producing a glass molded body requiring high transparency such as a glass dielectric layer formed on a glass substrate of a plasma display panel. SOLUTION: This glass composition contains plural kinds of oxides as the main components. The content of the main oxide components using PbO, B2O3 and SiO2 as essential components is >=95 wt.% of the whole in the composition. The main oxide components consist of 40 to 60% PbO, 25 to 40% B2O3, 1 to 10% SiO2, 0 to 15% BaO and at least one kind of oxide selected from the groups consisting of CaO, MgO and SrO by 0 to 10%.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to a glass composition (refers to a vitreous composition; the same applies hereinafter). In particular,
A glass composition suitably used for manufacturing a display panel (particularly a plasma display panel), a paste or other glass-forming material containing the glass composition as a main component related to glass formation, and a glass composition formed from the glass composition It relates to a glass molding.

[0002]

2. Description of the Related Art Conventionally, a glass composition of a so-called softening point firing type has been used for producing a dielectric or the like in a plasma display panel (PDP). For example,
A predetermined paste is prepared from this type of glass composition, and the paste is formed into a general PDP front glass substrate (P on which an image is projected) so as to have a predetermined shape and size.
It refers to the glass substrate on the front side of the DP. ) On one side. Next, a baking treatment is performed under a temperature condition near the glass softening point of the glass composition. As a result, the softening point firing type glass composition is formed under a relatively low temperature condition that does not adversely affect the physical properties of the glass substrate and the internal display electrodes (transparent electrodes) formed inside the glass substrate. A dielectric layer can be stably and efficiently formed on the PDP glass substrate. Regarding this, for example, JP-A-2000-226229 and JP-A-2
Japanese Patent Application Publication No. 000-228152 discloses a softening point firing type glass composition suitably used for forming a dielectric layer on a front glass substrate of the PDP.

[0003]

[Problems to be Solved by the Invention] By the way, the PD
P and other dielectric layers formed on display panels are required to have high transparency so that light can be transmitted efficiently. However, the above-mentioned conventional softening point firing type glass composition tends to contain a relatively large amount of internal bubbles during the firing process, and as a result, the glass molded article (such as the dielectric layer) formed from the glass composition is transparent. Sex is
It was not enough.

Accordingly, the present invention has been created to solve the problems associated with the conventional softening point firing type glass composition used for forming a dielectric layer in the above PDP and other uses. However, there is provided a glass composition which can be handled in the same manner as a conventional softening point firing type glass composition, and which can impart high transparency to a glass molded article (for example, the dielectric layer) produced therefrom. It is to be. Further, another object of the present invention is to provide a glass forming material containing the glass composition and a highly transparent glass molded body formed from the glass composition.

[0005]

Means for Solving the Problems The glass composition provided by the present invention is a glass composition containing a plurality of oxides as main components, and includes PbO, B ₂ O ₃ and SiO _2.
Is a main oxide component. Thus,
The content of the main oxide component is 95% by weight of the whole composition.
%, And the main oxide component has the following weight ratio: P
bO 40 to 60%, B ₂ O ₃ 25 to 40%, SiO ₂ 1
10%, BaO0-15%, CaO, MgO and SrO
At least one oxide selected from the group consisting of
Consist of 10% of each oxide.

[0006] The glass composition of the present invention having such a constitution forms a glass molded body with few internal bubbles even when fired at a temperature near the glass softening point of the glass composition. Therefore, according to the glass composition of the present invention, a PDP dielectric layer and other glass moldings having more excellent transparency are manufactured based on the same manufacturing process (firing conditions and the like) as the conventional softening point firing type glass composition. can do. In this specification, “transparency” refers to a property of a glass substance that indicates a degree to which light can pass without being absorbed or scattered. Further, “transmittance (%)” refers to a ratio of light transmitted in the thickness direction of light incident on a glass material (molded article) having a predetermined thickness.

The preferred glass composition of the present invention is characterized in that the total weight ratio of B ₂ O ₃ and BaO is 30 to 50% of the total main oxide component. According to the glass composition of the present invention having such a configuration, it is possible to impart higher transparency to a glass molded body formed from the glass composition. Particularly preferred as the glass composition of the present invention is that the weight ratio of at least one oxide selected from the group consisting of CaO, MgO and SrO is 2 to 10% of the entire main oxide component. Features. By including these oxides in such a ratio, the water resistance of the glass composition itself can be further improved.

A particularly preferred glass composition of the present invention is characterized in that the glass composition is formed into a powder having an average particle size of 1.5 to 3 μm (more preferably, 2 to 3 μm). According to the powdery glass composition having such a relatively large particle size range, a paste and other glass-forming materials having good dispersibility can be prepared, and a relatively high density and a predetermined shape (for example, the dielectric material of the PDP) can be prepared. Layer). At this time, as a result of the glass composition having the present configuration being formed into a powder having a relatively large particle diameter, the number of voids between particles that can be a factor of internal bubble generation can be reduced per unit volume. it can. For this reason, according to the glass composition of this structure, it is possible to suitably manufacture the above-described PDP dielectric layer and other glass molded bodies formed with high transparency and high density.

According to the present invention, there are provided pastes and other glass-forming materials containing the glass composition of the present invention having the above constitution as a main component involved in glass formation.
According to the glass forming material of the present invention, the same handling and processing as the glass forming material containing the conventional softening point firing type glass composition can be performed to form a more transparent glass molded body. Further, according to the present invention, there is provided a glass molded article (typically, a fired article) formed from the glass composition of the present invention. In the glass molded body of the present invention, high transparency is realized.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, a preferred embodiment according to the present invention will be described. The percentages (%) below are all percentages by weight.

First, the components of the glass composition of the present invention
I will explain about it. Main constituents of the glass composition of the present invention
The main oxide component is PbO, B₂O₃And S
iO ₂Is a required component. Other than these, optional configuration
BaO, CaO, MgO and SrO as elements
It may contain at least one oxide. Therefore, the present invention
The main oxide component contained in the glass composition of
Elementary PbO, B₂O₃And SiO₂Three types of oxidation
It may be composed of only objects.

PbO is a component that lowers the softening point of glass. If the content of PbO is less than 40% of the entire main oxide component of the glass composition of the present invention, the softening point will increase, and the conventional softening point firing type glass composition (especially for forming the dielectric layer of the PDP) Can not be handled in the same way as Further, the coefficient of thermal expansion is reduced and the difference in thermal expansion between the PDP and the glass substrate (typically made of soda lime silica glass) is increased, which makes the PDP unsuitable for use in forming a dielectric on such a glass substrate. . On the other hand, if the content of PbO is more than 60% of the entire main oxide component, the softening point is excessively lowered, so that it cannot be handled similarly to the conventional softening point firing type glass composition for forming a PDP dielectric layer. Further, since the coefficient of thermal expansion increases and the difference in thermal expansion from the PDP glass substrate increases, it becomes unsuitable for forming a dielectric on the glass substrate. Therefore, it is appropriate that the weight ratio of PbO is 40 to 60% of the total main oxide component of the glass composition, and the weight ratio of 50 to 60% is on the soda lime silica glass PDP glass substrate. It is particularly preferable for the purpose of forming a transparent dielectric layer.

B ₂ O ₃ is a component that lowers the softening point of glass, similarly to the above-mentioned PbO, and is an oxide that can improve the transmittance of a glass molded article formed from the glass composition of the present invention. . Therefore, one of the features of the present invention is that the content ratio of B ₂ O ₃ is large. If the content of B ₂ O ₃ is less than 25% of the total main oxide component, it becomes difficult to improve the transmittance as compared with the conventional softening point firing type glass composition. On the other hand, if the content of B ₂ O ₃ is more than 40% of the entire main oxide component, the water resistance is lowered, which is not preferable in handling. Further, since the coefficient of thermal expansion is reduced and the difference in thermal expansion between the PDP and the glass substrate is increased, the PDP is not suitable for forming a dielectric on the glass substrate. Therefore, B
The weight ratio of ₂ O ₃ is ₂ % of the entire main oxide component of the glass composition.
5 to 40% is appropriate, and the weight ratio is 30 to 40%.
% (Especially 35 to 40%) is preferable for forming a glass molded body having higher transparency.

[0014] SiO ₂ is an oxide that contributes to glass stability. If the content of SiO ₂ is less than 1% of the entire main oxide component of the glass composition, the glass state during firing will not be stable. On the other hand, SiO ₂ is 10% of the total main oxide component.
%, The softening point increases, and the conventional PD
It cannot be handled in the same way as the softening point firing type glass composition for forming the P dielectric layer. Further, the coefficient of thermal expansion rises and the above P
Since the difference in thermal expansion between the DP and the glass substrate becomes large, the DP becomes unsuitable for forming a dielectric on the glass substrate. Therefore, the weight ratio of SiO ₂ is 1% of the entire glass composition component.
% Is suitable, and such a weight ratio of 1% to 3% is particularly preferable for the purpose of forming a transparent dielectric layer on the PDP glass substrate.

BaO is an oxide capable of improving the transmittance of a glass molded body, similar to B ₂ O ₃ . Therefore, the transmittance can be further improved by adding BaO to 15% of the entire main oxide component. On the other hand, if the content of BaO is more than 15% of the entire main oxide component, the coefficient of thermal expansion increases, and the difference in thermal expansion from the PDP glass substrate of the above-described material increases, so that a dielectric is formed on the glass substrate. It is not suitable for use. Therefore, the weight ratio of BaO is 0 to 15 of the total main oxide component of the glass composition.
% Is appropriate, and such a weight ratio is 3 to 15% (particularly 5%).
-10%) is preferable for forming a glass molded body having higher transparency. In particular, it should also be noted a synergistic effect between the B ₂ O _3, a weight ratio of the combined B ₂ O ₃ and BaO is 30 to 50% of the entire main oxide component has a high transparency It is particularly preferred for forming glass moldings. In addition, from the viewpoint of achieving a high level of both the water resistance of the glass composition and the transparency of the glass molded body, the weight ratio of B ₂ O ₃ and BaO is 35 to 45% of the total main oxide component. Is particularly preferred.

[0016] CaO, MgO and SrO are all optional components that can be included in the main oxide component of the glass composition of the present invention. By mixing one or more of these oxides in an appropriate amount, the water resistance of the glass composition of the present invention can be improved. The content of these oxides is suitably not more than 10% of the entire main oxide component. If the content is more than 10%, the transparency of the fired glass molded body can be reduced, which is not preferable. As described above, in the glass composition of the present invention, B ₂ O ₃ and BaO are included in order to increase the transparency of the fired glass molded body. When the content is 30 to 50%, the content of the above three oxides is preferably set to 2 to 10% of the entire main oxide component. Thus, it is possible to achieve both a high level of transparency and a high level of water resistance of the glass composition itself after firing. Particularly, the mixing of CaO is effective.

The glass composition of the present invention has a main oxidation composition as described above.
May consist solely of a substance component, or the object of the present invention.
As long as it is possible to achieve a small amount of minor components (5% of the entire glass composition)
% Or less) and acids other than oxides contained in the main oxide component
Or a compound containing a halide or a halide. example
If necessary, adjust the glass softening point, transparency, glass stability, etc.
Al_TwoO_Three, Bi_TwoO_Three, ZnO, La_TwoO_Three, T
iO_Two, SnO_Two, ZrO _TwoEtc. to 5% or less of the whole composition
May be included as appropriate.

The glass composition of the present invention has the same glass softening point (typically 500 ° C. to 600 ° C.) and average thermal expansion coefficient (average linear expansion coefficient) as the above-mentioned conventional softening point firing type glass composition. : Typically 60 × 10 ⁻⁷ / ° C. to 8
0 × 10 ⁻⁷ / ° C.). For this reason, for example, the PD
When a transparent dielectric layer is formed on a P glass substrate (typically made of soda lime silica glass), it can be handled or treated in the same manner as a conventional softening point firing type glass composition. . In addition, the glass composition of the present invention can be fired at a relatively low temperature and can realize high transparency in the formed glass molded body. Therefore, the glass composition of the present invention is not limited to the use for forming the dielectric layer of the PDP, but may be applied to, for example, various silica glass products for surface decoration.

The method for producing the glass composition of the present invention is not particularly limited, and the same method as used for producing a conventional glass composition is used. Typically, a raw material prepared by mixing an appropriate amount of a compound for obtaining each oxide constituting the above-mentioned glass composition and, if necessary, other additives is mixed at a suitable high temperature (typically 900 ° C.). ~ 1300
(° C.) is used. Next, the melt is cooled (preferably quenched) to obtain a glassy state. The vitreous composition thus obtained can be formed into a desired form by various methods. For example, by pulverizing with a ball mill or appropriately sieving, the desired average particle size (typically 0.5
μm to 10 μm). When the powdery glass composition of the present invention is prepared by milling or the like, the average particle size is 1 to 5 μm, preferably 1.5 μm.
It is suitable for forming the dielectric layer of the PDP and other glass molded bodies with high transparency and high density (high strength) to 3 to 3 μm, more preferably 2 to 3 μm. Such a powdered glass composition having a relatively large particle size range is suitable for preparing pastes and other glass-forming materials having good dispersibility. Further, it can be applied or integrated at a relatively high density in a predetermined shape (for example, the shape of the dielectric layer of the PDP). Further, the number of voids per particle per unit volume can be reduced. Such a reduction in voids contributes to a reduction in the number of internal bubbles in the glass when the glass composition is fired. That is, it contributes to improving the transmittance of the glass molded body to be manufactured.

Next, a glass forming material containing the glass composition of the present invention will be described. A typical example of such a glass-forming material is a paste obtained by mixing the glass composition with water, a thermoplastic resin, a plasticizer, an organic solvent, and the like. For example, the paste for forming a dielectric layer comprising the glass composition of the present invention on the front glass substrate of the PDP is a glass composition of the present invention (typically, a powdery glass composition having the above average particle size). ), An organic vehicle (such as a thermoplastic resin), and a solvent. The organic vehicle used here may be of various types conventionally used for the preparation of this type of paste. Cellulose resins such as ethyl cellulose and hydroxyethyl cellulose, acrylic resins such as polybutyl methacrylate, polymethyl methacrylate, and polyethyl methacrylate, and polyvinyl butyral are preferable. The solvent is not particularly limited as long as it can disperse the glass composition and the vehicle of the present invention. Ester solvents such as butyl cellosolve acetate and butyl carbitol acetate, and ether solvents such as butyl carbitol are preferred. Terpineol, butyl carbitol acetate and the like are particularly preferred. Thus, typically, the content of the glass composition of the present invention is 30 to 90%, and the content of the organic vehicle and the solvent is 10 to 70%.
These are kneaded based on a usual method so that Thereby, the paste as the glass forming material of the present invention can be prepared.

Next, a preferred example in the case of forming a dielectric layer on the glass substrate of the above PDP using the paste according to the present invention will be described. The paste containing the glass composition of the present invention prepared as described above is applied on the PDP front glass substrate by means such as a doctor blade method, a roll coating method, and a screen printing method. Then
In a heating furnace, a temperature near the softening point (typically 500-6
(00 ° C.) for a predetermined time. This allows PD
A thin, dense and transparent dielectric layer can be formed on the front glass substrate of P.

Another typical example of a glass-forming material containing the glass composition of the present invention is a green sheet obtained by mixing the glass composition with a thermoplastic resin or the like. For example, a green sheet used to form a dielectric comprising the glass composition of the present invention on a substrate (typically, a silica glass substrate) of a display panel such as a PDP includes the glass composition of the present invention (typically a silica glass substrate). Is prepared by mixing a powdery glass composition having the above average particle size) with a thermoplastic resin. The thermoplastic resin used here may be of various types conventionally used to impart strength, flexibility and / or adhesiveness to the green sheet. Ethyl cellulose, polyvinyl butyral, polymethyl methacrylate and the like are preferred. In addition to these resins, a small amount of a plasticizer (for example, butylbenzyl phthalate, dibutyl phthalate) or the like may be added. Thus, typically, 70 to 85% of the glass composition of the present invention and 15 to 30% of the above-mentioned thermoplastic resin (including a plasticizer or the like as necessary) are mixed based on an ordinary method, Next, a slurry is prepared by adding toluene or an alcohol-based solvent. Then, the obtained slurry is formed into a sheet on a resin film made of PET or the like by a doctor blade method or the like. Thereafter, by drying the molded product, a green sheet from which the contained solvent and the like have been removed can be obtained.

Next, a preferred example in which a dielectric layer is formed on a glass substrate of a PDP using the green sheet according to the present invention will be described. The green sheet (including the glass composition of the present invention) prepared as described above is typically subjected to a temperature of 100 to 200 ° C. for 100 to 500 ° C.
Adhesion is performed by applying thermocompression bonding of kPa. Then
In a heating furnace, a temperature near the softening point (typically 500 to 6)
(00 ° C.) for a predetermined time. This allows PD
A dielectric layer of desired properties can be formed on the P glass substrate.

As described above, the glass composition of the present invention contains a large amount of B ₂ O ₃ or BaO which contributes to the improvement of transparency. As a result, the glass composition (ie, a glass-forming material containing the same) is produced. High transparency can be realized in the dielectric layer and other glass molded bodies obtained by firing. Therefore, the glass molded body according to the present invention is made of a conventional softening point firing type glass composition (PbO—B ₂ O ₃ —SiO ₂ system, Pb
A visible light region (typically, a wavelength of 400) is more than a glass molded body formed from OB ₂ O ₃ —SiO ₂ —Al ₂ O ₃ system or the like.
(At 750 nm). Although not particularly limited, a preferable glass molded article of the present invention has a wavelength of 6 μm when the thickness of the glass molded article (for example, a dielectric formed on a glass substrate of PDP) is 38 μm.
The spectral transmittance (linear transmittance) at 50 nm is 77% or more. 80% of such spectral transmittance
Those described above are particularly preferable as the glass molded article of the present invention (such as the above dielectric). On the other hand, another preferable glass molded article of the present invention has a spectral transmittance (linear transmittance) at a wavelength of 450 nm of 75% or more when the thickness of the glass molded article (such as the dielectric) is 38 μm. It is characterized by. Those having a spectral transmittance of 85% or more are particularly preferred as the glass molded article (such as the above dielectric) of the present invention.

[0025]

EXAMPLES The present invention will be described in more detail with reference to the following examples. The present invention is not limited to these examples.

Glass compositions according to the present invention having three compositions shown in Table 1 (Examples 1 to 3) and a conventional softening point firing type glass composition (Comparative Example 1) were prepared as comparative examples.
That is, in order to obtain the compositions having the compositions (% by weight) shown in Table 1, first, PbO, H ₃ BO ₃ , BaCO ₃ ,
SiO ₂ , CaCO ₃ , Mg carbonate hydroxide, SrCO ₃ , A
Raw materials appropriately selected from l ₂ O ₃ and the like were weighed so as to have a predetermined oxide content, and mixed with a mixer. The obtained mixture is placed in a platinum crucible and placed in an electric furnace under appropriate high temperature conditions (900 to 1200 ° C. is a preferable range: 1200 in this case).
° C). Next, the molten material taken out of the furnace is quenched by bringing it into contact with a low-temperature member (here, it is poured onto a stainless steel plate) to have a predetermined shape (here, a plate shape).
Glass. Thereafter, the obtained sheet glass was pulverized by a ball mill or the like to prepare a powdery glass composition of the present invention and a conventional glass composition having an average particle diameter of about 1.5 μm, respectively (Examples 1 to 3, Comparative example 1).

[0027]

[Table 1]

Next, using each of the four types of glass compositions obtained above (Examples 1 to 3 and Comparative Example 1), a total of 4
Various pastes (glass forming materials) were prepared. That is, 70 parts by weight of the obtained glass composition and 30 parts by weight of a terpineol solvent containing 5% of ethyl cellulose as an organic vehicle are thoroughly mixed (kneaded) using a stirrer (preferably a three-roll mill or the like). A paste was prepared. Hereinafter, pastes prepared from the glass compositions of Examples 1, 2, 3 and Comparative Example 1 are referred to as Examples 4, 5, 6 and Comparative Example 2, respectively.

Next, the paste obtained as described above was applied on a transparent silica glass plate having a thickness of about 1 mm. Thereafter, the glass substrate was placed in an electric furnace and fired at a temperature near the softening point (here, 550 ° C.) to form a glass film (glass molded body). Thus, Examples 4, 5,
6 and the paste according to Comparative Example 2, the thickness was 10, 2
Glass films of 0, 30, and 40 μm were formed on the glass plates, respectively.

Next, the light transmittance (linear transmittance and integrating sphere transmittance) of each of the obtained glass films was measured. In addition,
Here, the linear transmittance refers to a direction in which light is incident on one surface (front surface) of each glass molded body from a vertical direction, and the light is transmitted from the other surface (rear surface) of the glass molded body parallel to the one surface. Is a transmittance calculated by measuring the light amount of only the light emitted to the light source. On the other hand, the integrating sphere transmittance is a transmittance calculated by using an integrating sphere to measure not only the above light amount but also light whose refraction and / or scattering on the glass molded body and its surface has changed the emission direction. It is the rate. In this example, the linear transmittance (%) was measured using a measuring device (model: U3000) manufactured by Hitachi, Ltd. In addition, the integrating sphere transmittance (%) was measured using a measuring device (model: UV-3100) manufactured by Shimadzu Corporation. Table 2 shows the transmittance (%) at a wavelength of 550 nm calculated from the data measured by these measurement systems.

[0031]

[Table 2]

As shown in Table 2, the glass films manufactured from the pastes of Examples 4 to 6 had higher transmittance than the glass films manufactured from the conventional (Comparative Example 1) paste.
The glass film (thickness: 38 μm) manufactured from the paste of Example 4 has a wavelength in the visible light range (350 to 7).
The relationship between the linear transmittance (%) and the linear transmittance (%) (ie, the wavelength dependence of the transmittance) was measured. The result is shown in FIG. In this figure, the horizontal axis is the wavelength (nm), and the vertical axis is the linear transmittance (%). As is clear from FIG. 1, in the present glass film (thickness: 38 μm), for example, the linear transmittance at a wavelength of 650 nm is 75% or more (77% or more in this embodiment), and the linear transmittance at a wavelength of 450 nm and 550 nm. Were 75% or more, respectively. At other wavelengths, the transmittance is generally high, that is, 70% in the entire visible light range.
% (72% in the entire visible light range in this example)
Above). From the above results, the glass molded article formed from the glass composition according to the present example has higher transparency than the glass molded article formed from the conventional softening point firing type glass composition. Was supported. From observation of the glass surface with a microscope, it was found that Example 4
In the glass films manufactured from the pastes Nos. 6 to 6, the number of bubbles remaining inside the glass and the size of the bubbles are relatively small as compared with the glass film manufactured from the paste of the related art (Comparative Example 1). confirmed.

Next, the relationship between the average particle size of the powdery glass composition to be used and the transmittance of the obtained glass molded body (here, a glass film formed on a silica glass plate) was clarified. That is, when preparing the glass composition having the composition of Example 3 above, the average particle size was 1.3 μm by varying the degree of milling and further adding appropriate sieving.
m, 1.5 μm, 1.8 μm, 2.0 μm and 2.5
Each μm glass composition was prepared.

Next, a paste was prepared by adding and kneading an organic vehicle having the same weight ratio and components as described above to each of the obtained glass compositions. Hereinafter, pastes prepared from the respective glass compositions having average particle diameters of 1.3 μm, 1.5 μm, 1.8 μm, 2.0 μm and 2.5 μm were prepared in Examples 7, 8, 9, 10 and 11, respectively. I do. Next, each of the obtained pastes was applied on a transparent silica glass plate having a thickness of about 1 mm. Thereafter, the glass substrate is placed in an electric furnace, and is heated to a temperature near the softening point (here, 550).
C.) to form a glass film (glass molded body) having a thickness of about 50 μm. Thus, the transmittance (linear transmittance) at a wavelength of 550 nm of each of the obtained glass films was determined using the above-described measurement system. Table 3 shows the results.

[0035]

[Table 3]

As shown in Table 3, the larger the average particle size of the glass composition used here, the higher the transmittance at the above wavelength of the glass molded body (glass film) formed therefrom. Although detailed data is not shown, compared with the case where a glass composition having an average particle size of 0.5 to 1.0 μm is used, such an increase in transmittance is caused by an increase in the average particle size of the glass composition used. This was particularly noticeable in the case of 1.5 to 3.0 μm. In addition, observation of the glass surface with a microscope confirmed that the number of bubbles remaining inside the glass was smaller as the glass film was manufactured from a paste having a larger particle size.

[0037]

According to the glass composition of the present invention and a paste or other glass-forming material containing the glass composition,
Based on the same manufacturing process (firing conditions and the like) as when a conventional softening point firing type glass composition is used, a glass molded body (for example, on the above-mentioned PDP glass substrate) that realizes higher transparency than the conventional glass composition Dielectric layer).

[Brief description of the drawings]

FIG. 1 is a graph showing a linear transmittance of a glass film according to one example for each wavelength in a visible light region.

Continued on the front page F-term (reference) 4G062 AA08 AA09 AA15 BB04 DA03 DB01 DC04 DC05 DD01 DE01 DF05 DF06 EA01 EA10 EB01 EC01 ED01 ED02 ED03 EE01 EE02 EE03 EF01 EF02 EF03 EG01 EG01 F01 FG01 F01 EF01 EF01 EF01 FG01 FL01 GA01 GA10 GB01 GC01 GD01 GE01 HH01 HH03 HH05 HH07 HH09 HH11 HH13 HH15 HH17 HH20 JJ01 JJ03 JJ05 JJ07 JJ10 KK01 KK03 KK05 KK07 KK10 MM07 MM12 NN26 NN32 PP13 PP07 PP05 A07 KB07 A07KB07 A07

Claims (5)

[Claims] 1. A glass composition comprising a plurality of oxides as main constituents, wherein the content of a main oxide component comprising PbO, B ₂ O ₃ and SiO ₂ as essential constituents is the total composition. and the weight of 95% or more, the principal oxide component following weight _{proportions: PbO 40~60%; B 2 O} 3 25~40%; SiO 2 1~10%; BaO 0~15%; CaO, MgO And at least one oxide selected from the group consisting of SrO and 0-10%. 2. The glass composition according to claim 1, wherein the total weight ratio of B ₂ O ₃ and BaO is 30 to 50% of the entire main oxide component. 3. The glass composition according to claim 1, wherein the weight ratio of at least one oxide selected from the group consisting of CaO, MgO and SrO is 2 to 10% of the entire main oxide component. object. 4. The glass composition according to claim 1, which is formed into a powder having an average particle size of 1.5 to 3 μm. 5. A glass-forming material comprising the glass composition according to claim 1 as a main component involved in glass formation.