JP2008105893A - Glass composition and display panel using the same - Google Patents

Abstract

Disclosed is a glass composition suitable for a display panel, having a low dielectric constant, a low softening point, and a high water resistance.
SOLUTION: At least B ₂ O ₃ , R ₂ O (R is one or more of Li, Na and K) and Ln ₂ O ₃ (Ln is one or more selected from rare earth metals and Al) are included. The content of B ₂ O ₃ is 50 wt% or more and 95 wt% or less, the content of Ln ₂ O ₃ is 0.2 wt% or more and 10 wt% or less, and is substantially free of lead. A low softening point glass composition characterized by the above.
[Selection] Figure 1

Description

  The present invention relates to a glass composition suitable for applications such as electrode coating, and a display panel using the same, particularly a plasma display panel.

  In display devices and integrated circuits such as plasma display panels (hereinafter abbreviated as PDP), field emission displays, liquid crystal display devices, fluorescent display devices, ceramic laminated devices, and hybrid integrated circuits, electrodes made of Ag, Cu, etc. are provided on the surface thereof. And a substrate having wiring is used. In order to protect these electrodes and wirings, they may be covered with an insulating glass material. Here, a PDP which is a representative display device will be described as an example.

  Generally, a PDP has a structure in which a pair of electrodes regularly arranged on two opposing glass substrates are provided, and a gas mainly composed of an inert gas such as Ne or Xe is enclosed between the electrodes. A voltage is applied to the electrodes to generate a discharge in minute cells around the electrodes, thereby causing each cell to emit light and display. These electrodes are covered and protected with an insulating glass material called a dielectric layer.

  For example, a transparent electrode is formed on a glass substrate that serves as a front plate of an AC type PDP, and a metal electrode such as Ag, Cu, or Al having a lower resistivity is further formed thereon. A dielectric layer is formed to cover the composite electrode, and a protective layer (MgO layer) is further formed thereon.

  For the dielectric layer formed so as to cover the electrodes, glass having a low softening point is usually used. The dielectric layer is formed by applying a paste containing glass powder so as to cover the electrodes by a screen printing method, a die coating method, or the like, and then baking the paste.

Properties required for the glass composition forming the dielectric layer include:
(1) Since it is formed on the electrode, it is insulative.

  (2) In a large-area panel, in order to prevent warping of the glass substrate, peeling of the dielectric layer and cracking, the thermal expansion coefficient of the glass composition is a value that is not much different from that of the substrate material (in practice, a slightly smaller value). Value is desirable).

  (3) If it is for front plates, it is an amorphous glass having a high visible light transmittance in order to efficiently use light generated from the phosphor as display light.

(4) The softening point is low so as to match the heat resistance of the substrate glass.
Etc.

As a glass substrate used for PDP, there are soda lime glass which is a window glass which is produced by a float process and is generally easily available, and high strain point glass developed for PDP. Heat resistance up to 75 × 10 ^{−7 to} 85 × 10 ⁻⁷ / ° C.

For this reason, about (2) mentioned above, the thermal expansion coefficient is desirably about 70 × 10 ⁻⁷ to 80 × 10 ⁻⁷ / ° C. Regarding (4), since the baking of the glass paste needs to be performed at 600 ° C. or lower, which is the strain point of the glass substrate, the softening point is at least so that the glass paste is sufficiently softened even when baking at a temperature of 600 ° C. or lower. It needs to be 595 ° C. or lower, more desirably about 590 ° C. or lower.

  In addition, after forming a dielectric layer of glass, it may be reheated to around 500 ° C. in a sealing process or the like. In this case, if the glass transition temperature is low, defects such as glass breakage are generated. In some cases, the glass transition temperature is 465 ° C. or higher, more preferably 475 ° C. or higher, for the dielectric layer.

At present, PbO—SiO ₂ glass mainly composed of PbO is mainly used as a glass material that satisfies the above demands.

  However, in consideration of recent environmental problems, glass materials for dielectric layers that do not contain Pb have been demanded. In addition, the dielectric constant of the glass material is preferably low in order to reduce the power consumption of the PDP. However, PbO-based glass has a high relative dielectric constant of 10 or more, and is required to be lower than the current level.

As a glass not containing Pb, a Bi ₂ O ₃ —B ₂ O ₃ —ZnO—SiO ₂ glass material containing zinc borate as a main component and having a low softening point by containing Bi instead of Pb (for example, patents) Literature 1) and the like have been developed, but these Bi-based materials also have a problem that the relative dielectric constant is as high as about 9 to 13 like the Pb-based materials. For this reason, a material having a lower dielectric constant is demanded.

Therefore, in order to achieve both a low dielectric constant and a low softening point, materials that have achieved a relative dielectric constant of about 7 using a borate glass containing an alkali metal instead of Pb have also been proposed (for example, Patent Documents 2 to 4). However, a material having a lower relative dielectric constant of about 6 or less has not been known.
JP 2001-139345 A JP-A-9-278482 JP 2000-313635 A Japanese Patent Laid-Open No. 2002-274883

  According to the inventor's study, in the alkali borate glass, in order to make the relative dielectric constant about 6 or less, it is necessary to increase the amount of boron. There was a problem that water resistance was low.

  The final use form of the dielectric layer is sealed in the panel, and there is no moisture in the surroundings, so this is not a problem, but it is stored as glass powder or its paste before reaching the final use form. In this state, if the water resistance is low, it reacts with moisture in the atmosphere, resulting in deterioration of characteristics and poor storage stability. In addition, after forming an electrode on a glass substrate and forming a dielectric layer thereon, the glass substrate may be cut with a diamond grindstone. If it is low, film thickness fluctuations and insulation defects may occur.

  In addition, when boron is increased in an alkali borate glass, the softening point becomes extremely low and it can be used as a sealing glass, but in this case, the water resistance is extremely lowered, and as a sealing material There was a problem of not playing the role.

  That is, the alkali borate glass containing a large amount of boron has low water resistance, and no practically usable glass has been obtained.

  An object of the present invention is to provide a glass composition having a low softening point, a low dielectric constant, excellent water resistance, and capable of producing a display with excellent display performance.

The present invention includes at least B ₂ O ₃ , R ₂ O (R is one or more of Li, Na and K), and Ln ₂ O ₃ (Ln is one or more selected from rare earth metals and Al), The content of B ₂ O ₃ is 50 wt% or more and 95 wt% or less, the content of Ln ₂ O ₃ is 0.2 wt% or more and 10 wt% or less, and is substantially free of lead. And a low softening point glass composition.

  The present invention also provides a display panel using the glass composition according to the present invention. The 1st display panel by this invention is a display panel by which the electrode is coat | covered with the dielectric material layer containing a glass composition, Comprising: This glass composition is the said glass composition by this invention. The second display panel according to the present invention has a dielectric layer containing a glass composition between a glass substrate and an electrode, and the glass composition contained in the dielectric layer is the glass composition according to the present invention. .

  The present invention also provides a PDP using the glass composition of the present invention. PDP electrode coating glass, partition wall forming glass, or sealing glass is the glass composition according to the present invention.

  According to the present invention, it is possible to provide a glass composition having a low softening point, a low dielectric constant, high water resistance, and capable of producing a display with excellent display performance.

(Embodiment 1)
As a result of detailed studies, the inventors have found that, in alkali borate glasses, the reduction in the water resistance of the glass that occurs when the boron content is increased in order to lower the dielectric constant and softening point, rare earth metals or Al It was found that this can be prevented by adding the oxide.

  The essential main components of the glass of the present invention are an alkali metal oxide and boron oxide, and the essential subcomponent is a rare earth metal or Al oxide.

The reason why the amount of the rare earth or Al oxide Ln ₂ O ₃ is limited to 0.2 wt% or more and 10 wt% or less is that the effect of addition becomes unclear below this, and if it exceeds this, the relative dielectric constant due to addition This is because the increase in the temperature, the increase in the softening point, and the decrease in the thermal expansion coefficient become large.

  As for Ln, whichever rare earth metal or Al is selected, a certain degree of effect can be obtained by using any element except Pm. However, La has the greatest effect of improving water resistance, and Nd has a relatively large effect.

  Al was less effective in improving water resistance than rare earth metals. However, the effects of increasing the dielectric constant, increasing the softening point, and increasing the thermal expansion coefficient are relatively weak, and the addition of a small amount has a characteristic that the softening point is rather lowered.

  On the other hand, there is a case where it is not desirable to color the glass yellow by addition, such as Ce, or red, such as Er, and conversely, the glass is colored blue by addition, such as Nd. Things may be desirable.

  In view of industrial use, an inexpensive one is desirable. In this respect, Al is most desirable, but among rare earths, La is most desirable, and Ce, Y, Nd, Gd, and Sm follow this. Considering the above characteristic and price aspects comprehensively, La is the most desirable as a single component, Nd is desirable next, Al, Y, Gd is followed by Ce, Sm, An unseparated mixture of rare earth metal oxides before purification may be used. Moreover, the combined use of rare earth metals such as Al and La and Nd can secure the effect of improving water resistance while reducing the amount of relatively expensive rare earths used, increasing the softening point, decreasing the thermal expansion coefficient, and reducing the dielectric constant. This is desirable because the increase can be suppressed relatively.

  There are 17 types of rare earth metals, Sc, Y, La, Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, and Lu. Experiments are not possible for Pm that is only present, and is outside the scope of the present invention.

The amount of B ₂ O ₃ is preferably 50% by weight or more and 95% by weight or less because if it is less than this, the dielectric constant and softening point of the obtained glass will not be so low, and the water resistance of the glass will not decrease so much. This is because the necessity of adding Ln _x O _y is reduced, and if it is more than this, the glass becomes too unstable, and even when Ln _x O _y is added, the water resistance becomes insufficient.

If the glass of the present invention is composed of an alkali metal oxide, boron oxide and rare earth metal or an oxide of Al as described above, it is possible to obtain a glass having a low dielectric constant, a low softening point and high water resistance. However, when it is actually used for various glasses of displays such as PDP, in order to optimize the characteristics such as glass transition temperature, softening point, thermal expansion coefficient, etc. according to each application, other components than these It is desirable to include. Desirable components that can be included include ZnO, alkaline earth metal oxides (MgO, CaO, SrO, BaO), SiO _{2 and the} like. As a desirable composition range including these,
50% by weight ≦ B ₂ O ₃ ≦ 95% by weight
3 wt% ≦ R ₂ O ≦ 25 wt% (R is one or more of Li, Na, K)
0.2 wt% ≦ Ln ₂ O ₃ ≦ 10 wt% (Ln is one or more of rare earth or Al)
0 wt% ≤ MO ≤ 50 wt%
(M is one or more of Mg, Ca, Sr, Ba, Zn)
0% by weight ≦ SiO ₂ ≦ 26% by weight
Especially for the low dielectric constant PDP dielectric layer,
60% by weight <B ₂ O ₃ ≦ 90% by weight
5 wt% ≦ R ₂ O ≦ 20 wt% (R is one or more of Li, Na, K)
0.2 wt% ≦ Ln ₂ O ₃ <5 wt% (Ln is one or more of rare earth or Al)
5 wt% ≤ MO ≤ 25 wt%
(M is one or more of Mg, Ca, Sr, Ba, Zn)
A range of 0 wt% ≦ SiO ₂ ≦ 10 wt is desirable.

The role of each component within the above composition range is described. B ₂ O ₃ is an essential component of the glass of the present invention as described above, lowering the dielectric constant of the glass, lowering the glass transition temperature and softening point. Widens the difference between the softening point and the glass transition temperature, increases the coefficient of thermal expansion, and lowers the chemical durability such as water resistance.

As described above, R ₂ O is an essential component of the glass of the present invention, stabilizes the glass, increases the dielectric constant, decreases the softening point and the glass transition temperature, and narrows the difference between the softening point and the glass transition temperature. Increase the coefficient of thermal expansion. In particular, when used as a coating material for an Ag electrode, if there is a large amount of R ₂ O, Ag is once oxidized, diffused in the glass, and then reduced and deposited as a yellow colloid, so-called yellowing is likely to occur. . Since this yellowing phenomenon deteriorates the display performance of the display, it is better that the amount of R ₂ O is not so much for the dielectric layer, but if it is too little, the thermal expansion coefficient of the glass becomes too small. When Li, Na, and K are compared, K tends to increase the thermal expansion coefficient, and yellowing is relatively difficult to occur. Therefore, K ₂ O is most preferable among these three types.

As described above, Ln ₂ O ₃ is an essential subcomponent of the present invention and a component that characterizes the present invention. Ln ₂ O ₃ is used to improve the water resistance of the glass, but when added, increases the dielectric constant, increases the glass transition temperature and softening point, and decreases the thermal expansion coefficient.

  Although MO is not an essential component of the glass of the present invention, it increases the dielectric constant of the glass, increases the glass transition temperature and the softening point, reduces the difference between the glass transition temperature and the softening point, decreases the thermal expansion coefficient, Has the effect of increasing the stability of the machine. In particular, for a PDP dielectric layer, the glass transition temperature is high to some extent and the softening point must be low, that is, the difference between the two needs to be small. It may be said that it is an essential component for the body layer.

  However, when the addition amount increases, the softening point and the dielectric constant become too high, and the thermal expansion coefficient becomes too small.

Although SiO ₂ is not an essential component of the glass of the present invention, it increases the stability of the glass, lowers the dielectric constant, increases the glass transition temperature and the softening point, widens the difference between the softening point and the glass transition temperature, and the thermal expansion coefficient. Is effective in increasing the chemical durability. Therefore, a small amount may be added, but if it is used in a large amount, the softening point becomes too high.

  As described above, each component has a different contribution to glass stability, dielectric constant, glass transition temperature, softening point, thermal expansion coefficient, water resistance, and the like. The required properties differ depending on the application of the glass. Even in the case of PDP, for example, the softening point, glass transition temperature, thermal expansion coefficient, etc. required for the dielectric layer are different from those required for the sealing material (generally, the dielectric layer has a softening point or glass Since the transition point is high and the thermal expansion coefficient is small), it is desirable to optimize the content according to the application.

Since the main purpose of the present application is to eliminate the decrease in water resistance caused by alkali borate glass, particularly when the content of B ₂ O ₃ is large, by using Ln ₂ O ₃ , elements other than the above, for example, Ti, Zr It is also possible to add oxides such as Mn, Nb, Ta, Te, Bi, Sb, P, Ag, and Cu as long as the original characteristics of the target glass are not lost. However, it is known that Mn, Bi, etc. are colored by addition of glass itself, and it is desirable that the addition amount be small. The desirable content is 5% by weight or less, more desirably 1% by weight or less.

  It is preferable that the glass composition of the present invention does not substantially contain lead (Pb). In the present specification, “substantially free” means that it is industrially difficult to remove and allows a very small amount of the component that does not affect the properties. Specifically, the content is 1% by weight. % Or less, preferably 0.1% by weight or less.

In the present specification, the composition of the oxide glass is represented by the weight ratio of each component element as an oxide, as is generally done. However, this notation does not limit the valence of each cation in the glass. The rare earth metal oxide is also expressed as Ln ₂ O ₃ , but the valence of the rare earth metal is not limited to trivalent. Ce, Pr, and Tb oxide raw materials are usually commercially available as CeO ₂ , Pr ₆ O ₁₁ , and Tb ₄ O _7. These are 0.1 weight in terms of Ln ₂ O _3. % To 10% by weight may be included.

  Next, a PDP will be described as a specific example of the display panel of the present invention. FIG. 1 is a partially cutaway perspective view showing the main configuration of the PDP according to the present embodiment. FIG. 2 is a cross-sectional view of this PDP. This PDP is an AC surface discharge type and has the same configuration as the PDP according to the conventional example 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 is formed so as to cover the front glass substrate 2, the display electrode 5 composed of the transparent conductive film 3 and the bus electrode 4 formed on the inner side surface (the surface facing the discharge space 14), and the display electrode 5. The dielectric layer 6 and the dielectric protective layer 7 made of magnesium oxide formed on the dielectric layer 6 are provided. The display electrode 5 is formed by laminating a bus electrode 4 made of Ag or the like on a transparent conductive film 3 made of ITO or tin oxide in order to ensure good conductivity.

  The back plate 8 includes a back glass substrate 9, an address electrode 10 formed on one side thereof, a dielectric layer 11 formed so as to cover the address electrode 10, and a partition wall 12 provided on the top surface of the dielectric layer 11. And a phosphor layer formed between the barrier ribs 12. The phosphor layer is formed so that the red phosphor layer 13 (R), the green phosphor layer 13 (G), and the blue phosphor layer 13 (B) are arranged in this order.

For the dielectric layer 6 and / or the dielectric layer 11, preferably the dielectric layer 6, the glass composition according to the present invention described above is used. Moreover, you may use the glass composition of this invention as the partition 12. FIG. The dielectric layer 6 needs to be transparent, but the dielectric layer 11 and the partition wall 12 do not need to be transparent. Therefore, SiO ₂ having a lower dielectric constant is dispersed in the glass of the present invention as a filler. You may use what was contained. Further, although not shown here, if a layer containing the glass of the present invention is formed between the glass substrate and the display electrode 5 or between the glass substrate and the address electrode, the influence of the dielectric constant of the substrate glass can be reduced. Moreover, the glass of this invention can also be used as a glass material for sealing a front plate and a back plate. In the following, the case where the glass of the present invention is used for the dielectric layer 6 will be described as an example. However, the glass of the present invention is applied to the dielectric layer 11, the partition 12, the dielectric layer between the substrate / electrode, or the sealing layer. Even when the composition is used, the glass composition of the present invention can be used favorably in a PDP because of the low dielectric constant, low softening point, high water resistance, appropriate thermal expansion coefficient, and the like.

As the phosphor constituting the phosphor layer, for example, BaMgAl ₁₀ O ₁₇ : Eu is used as a blue phosphor, Zn ₂ SiO ₄ : Mn is used as a green phosphor, and Y ₂ O ₃ : Eu is used as a red phosphor. it can.

  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 face each other, and are joined using a sealing member (not shown).

  In the discharge space 14, a discharge gas (filled gas) made of a rare gas component such as He, Xe, or Ne is sealed at a pressure of about 66.5 to 79.8 kPa (500 to 600 Torr).

  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.

  The dielectric layer 6 is usually made into a glass paste by adding a binder or a solvent for imparting printability to a glass powder, and this glass paste is applied onto an electrode formed on a glass substrate. It is formed by firing.

  The glass paste contains glass powder, a solvent, and a resin (binder), but other components such as a surfactant, a development accelerator, an adhesion assistant, an antihalation agent, a storage stabilizer, and an antifoaming agent. Additives according to various purposes such as an agent, an antioxidant, an ultraviolet absorber, a pigment, and a dye may be included.

  The resin (binder) contained in the glass paste is not particularly limited as long as it is generally used. For example, from the viewpoint of cost, safety, etc., cellulose derivatives such as nitrocellulose, methylcellulose, ethylcellulose, carboxymethylcellulose, polyvinyl Alcohol, polyvinyl butyral, polyethylene glycol, carbonate resin, urethane resin, acrylic resin, melamine resin, or the like may be used.

  The solvent in the glass paste is not particularly limited as long as it is generally used. From the viewpoint of cost, safety, etc., and from the viewpoint of compatibility with the binder resin, an appropriate organic solvent may be selected. These solvents may be used alone or in combination of two or more. Specifically, ethylene glycol monoalkyl ethers; ethylene glycol monoalkyl ether acetates; diethylene glycol dialkyl ethers; propylene glycol monoalkyl ethers; propylene glycol dialkyl ethers; propylene glycol alkyl ether acetates; Organic solvents such as esters; alcohols such as terpineol and benzyl alcohol; and the like can be used.

  Typically, the glass paste is 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 thickness of the dielectric layer 6 is preferably about 10 μm to 50 μm in order to achieve both insulation and light transmittance.

  Next, a method for manufacturing the above PDP will be described with an example. First, a front plate is produced. A plurality of line-shaped transparent electrodes are formed on one main surface of the flat front glass substrate. Subsequently, after the silver paste is applied on the transparent electrode, the entire front glass substrate is heated, thereby baking the silver paste and forming the display electrode.

  A glass paste containing the dielectric layer glass in the PDP of the present invention is applied to the main surface of the front glass substrate by a blade coater method so as to cover the display electrodes. Thereafter, the entire front glass substrate is held at 90 ° C. for 30 minutes to dry the glass paste, and then baked at a temperature of about 580 ° C. for 10 minutes.

  Magnesium oxide (MgO) is deposited on the dielectric layer by an electron beam evaporation method and baked to form a protective layer. The firing temperature at this time is around 500 ° C.

  Next, a back plate is produced. After applying a plurality of silver pastes in a line on one main surface of a flat back glass substrate, the entire back glass substrate is heated and the silver paste is baked to form address electrodes.

  A partition wall is formed by applying a glass paste between adjacent address electrodes and firing the glass paste by heating the entire back glass substrate.

  By applying phosphor inks of R, G, and B colors between adjacent barrier ribs, and heating the back glass substrate to about 500 ° C. and baking the phosphor ink, a resin component in the phosphor ink (Binder) and the like are removed to form a phosphor layer.

  The front plate and the back plate thus obtained are bonded using a sealing glass. The temperature at this time is around 500 ° C. Thereafter, after the sealed interior is evacuated to high vacuum, a rare gas is sealed. A PDP is obtained as described above.

  The above-mentioned PDP and its manufacturing method are examples, and the present invention is not limited to this. As the PDP to which the present invention is applied, the surface discharge type as described above is typical, but the present invention is not limited to this and can 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.

  The glass composition of the present invention is not limited to PDP, but can be effectively used for a display panel that needs to be mixed with a resin to form a paste, and to perform a coating and baking process.

  Hereinafter, the present invention will be described in more detail with reference to examples. In the following examples, PDP dielectric layer glass is mainly used, but the present invention is not limited to this.

(Example 1)
As starting materials, oxides or carbonates of various kinds of metals of reagent grade or better were used. These raw materials were weighed so that the weight ratio in terms of each oxide was as shown in (Table 1), mixed well, then placed in a platinum crucible and placed in an electric furnace at 900 to 1100 ° C. for 2 hours. Melted. The obtained melt was quenched by pressing it with a brass plate to produce a glass cullet. The glass cullet was pulverized to an average particle size of about 2 to 3 μm, and the glass transition temperature and the softening point Ts were measured using a TG8110 macro differential thermal analyzer manufactured by Rigaku.

  Next, the glass cullet was remelted, poured into a mold, annealed at a temperature of glass transition temperature + 40 ° C. for 30 minutes, and then gradually cooled to prepare a glass block. From this glass block, a 4 mm × 4 mm × 20 mm rod was prepared by cutting, and a thermal expansion coefficient α between 30 ° C. and 300 ° C. was measured using a RGAKU TMA8310 type thermomechanical analyzer. In addition, a plate of 20 mm × 20 mm × thickness of about 1 mm was made from a glass block by cutting, and both surfaces were mirror-polished, and then a gold electrode was vapor-deposited on the surface. Using an impedance analyzer 4294A made by Agilent, the frequency was set to 1 kHz The capacitance was measured, and the relative dielectric constant ε was calculated from the area and thickness of the sample.

  Next, in order to evaluate the water resistance due to the glass composition, a 10 × 10 × 30 mm block was cut out from the glass block, heat-treated at a temperature 10 ° C. lower than the softening point to form a transparent block, and then the size and weight were measured. . The block was immersed in hot water at 80 ° C. for 24 hours, and then dried well. The weight was measured again, and the dissolved thickness was determined from the reduced weight and the surface area of the block, and this was divided by 24. The dissolution rate s (μm / h) was determined.

The results of each evaluation are shown in (Table 1). In the table, the unit of the softening point Ts is ° C., and the unit of the thermal expansion coefficient α is × 10 ⁻⁷ / ° C.

No. of (Table 1). 1 to 9, while increasing the amount of B ₂ O ₃ , the softening point is 590 ° C. or less and the thermal expansion coefficient is 70 to 80 × 10 ⁻⁷ / ° C. for the dielectric layer for PDP. It is a sample in which the component amount is adjusted. No. 10 and 11 are obtained by further increasing the amount of B ₂ O _{3. In} this composition range, it is difficult to obtain characteristics suitable for the dielectric layer even if other component amounts are adjusted, but the softening point is lower. Since it is expected to be, it was produced considering the use as a sealing material. However, no. No. 11 does not show glass characteristics because the synthesized glass has high hygroscopicity and the reliability of the measured characteristic value is low.

In these samples, No. _{2 with} a small amount of B ₂ O ₃ was used. No composition dependency of the dissolution rate was observed in Nos. 1 and 2, but the amount of B ₂ O ₃ was 50% by weight and the relative dielectric constant was 6.3. The dissolution rate starts to increase from No. 3, and when it exceeds 60% by weight, the dissolution rate suddenly increases. In 10 and 11, the original block shape could not be retained by the hot water treatment at 80 ° C., and the dissolution rate could not be measured.

These No. No. 1 to 11 with 2% by weight of La ₂ O ₃ added. 12-22. However, the original No. Simply adding _La 2 _{O 3} with respect to the composition of 1 to 11, increase of softening point, a decrease in thermal expansion coefficient, an increase in the dielectric constant increases, contribution to these characteristics, _La 2 _{O 3} added If was reduced mainly CaO and ZnO with a relatively similar effect, B ₂ O ₃ is not reduced too much, the softening point and thermal expansion coefficient, dielectric constant, the addition of La ₂ O ₃ so as not to only change possible ing. As a result, No. containing La ₂ O ₃ . Nos. 12 to 21 showed high water resistance even when the amount of B ₂ O ₃ exceeded 50 to 60%, and high water resistance even at a low dielectric constant or a low softening point.

However, in the composition range where the water resistance is not so low and the amount of B ₂ O ₃ is relatively small, the improvement of the water resistance due to the addition is not clear, and there is a demerit that the softening point and the dielectric constant rise to some extent. Therefore, it is desirable to use in a composition range in which the amount of B ₂ O ₃ exceeds 50% by weight, further exceeds 60% by weight, and the water resistance when La ₂ O _{3 is} not added is clearly reduced. Further, in the region where the amount of B ₂ O ₃ exceeds 90% by weight, it is difficult to maintain the characteristics for the dielectric layer. In No. 22, satisfactory water resistance could not be obtained even when La ₂ O ₃ was added. Therefore, the amount of B ₂ O ₃ is desirably 95% by weight or less, and more desirably 90% by weight or less.

Next, no. 18 and No. In Nos. 23 to 28, the amount of B ₂ O ₃ was made constant at 70% by weight, and the amount of La ₂ O ₃ was changed from 0.1% by weight to 12% by weight. This is no. The amount of La ₂ O ₃ was gradually increased with respect to the composition of No. 7, but in this case as well, the amount was reduced mainly in CaO and ZnO so that appropriate characteristics for the dielectric layer would not change much. The amount of La ₂ O ₃ was increased. As a result, although the effect of addition was not significant at the addition amount of 0.1% by weight, an obvious effect was observed at 0.2% by weight or more. However, no. No. 12, even if other components were adjusted, an increase in softening point and a decrease in thermal expansion coefficient could not be ignored. Therefore, the addition amount must be 10% by weight or less.

The inventor examined combinations of various compositions other than the above. Moreover, although MgO, SrO, BaO was used instead of CaO, or Li ₂ O or Na ₂ O was used instead of K ₂ O, the amount of B ₂ O _{3 was} 50 to 95 in any case. by adding the Ln ₂ O ₃ 0.2 to 10.0% by weight% by weight of the glass, a low dielectric constant, low softening point, it was possible to obtain excellent glass water resistance.

(Example 2)
In the same manner as in Example 1, B ₂ O ₃ : SiO ₂ : ZnO: CaO: K ₂ O: Ln ₂ O ₃ = 70.0: 1.5: 15.5: 1.5: 9.5: Various raw material powders were weighed so as to have a weight ratio of 2.0. Here, oxides of Sc, Y, La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, and Al were used as Ln. From this raw material powder, glass was produced in the same manner as in Example 1 and evaluated in the same manner as in Example 1. For comparison, a sample to which Ln ₂ O ₃ was not added and a sample to which 2.0% by weight of CuO, TiO ₂ , and Ta ₂ O ₅ were added were also prepared and evaluated. The results are shown in (Table 2). In the table, the unit of glass transition temperature Tg and softening point Ts is ° C., and the unit of thermal expansion coefficient α is × 10 ⁻⁷ / ° C.

  As is clear from (Table 2), even when rare earth other than La or Al is added, although there is a difference in degree, the dissolution rate is clearly reduced and water resistance is improved as compared with the case where no addition is made. The other characteristics of the glass were slightly different, but not so great. La had the highest water resistance, followed by Nd, followed by Al, which was clearly higher in water resistance than no addition, but the effect of improving water resistance was lower than that in rare earth. Compared to these, the addition of Cu, Ti, Ta almost did not improve the water resistance at all.

(Example 3)
In the same manner as in Example 1, B ₂ O ₃ : ZnO: CaO: K ₂ O: La ₂ O ₃ : Al ₂ O ₃ = 70.0: 1.5: 15.5: 1.5: 9. Various raw material powders were mixed for a weight ratio of 5: 1.0: 1.0, put in a platinum crucible, melted at 1100 ° C. for 2 hours in an electric furnace, and then a glass cullet was produced by a twin roller method. The glass cullet was pulverized by a dry ball mill to produce a powder. The average particle size of the obtained glass powder was about 3 μm. When the characteristics of this glass were evaluated in the same manner as in Example 1, the relative dielectric constant was 5.6, the glass transition temperature was 482 ° C., the softening point was 580 ° C., the thermal expansion coefficient was 72 × 10 ⁻⁷ / ° C., The dissolution rate was 1.4 μm / h.

  To this powder, ethyl cellulose as a binder and α-terpineol as a solvent were added and mixed with three rolls to obtain a glass paste.

  Next, an ITO (transparent electrode) material was applied in a predetermined pattern on the surface of a front glass substrate made of flat soda-lime glass having a thickness of about 2.8 mm and dried. Next, a plurality of silver pastes, which are a mixture of silver powder and an organic vehicle, were applied in a line shape, and then the front glass substrate was heated, whereby the silver paste was baked to form display electrodes.

  The glass paste mentioned above was apply | coated to the front panel which produced the display electrode using the blade coater method. Thereafter, the front glass substrate was held at 90 ° C. for 30 minutes, the glass paste was dried, and baked at a temperature of 590 ° C. for 10 minutes to form a dielectric layer having a thickness of about 35 μm.

  Magnesium oxide (MgO) was deposited on the dielectric layer by an electron beam deposition method, and then baked at 500 ° C. to form a protective layer.

  On the other hand, a back plate was produced by the following method. First, address electrodes mainly composed of silver were formed in a stripe shape on a rear glass substrate made of soda lime glass by screen printing, and then a dielectric layer having a thickness of about 40 μm was formed in the same manner as the front plate. .

  Next, partition walls were formed on the dielectric layer using glass paste between adjacent address electrodes. The partition was formed by repeating screen printing and baking.

  Subsequently, the phosphor layer of red (R), green (G), and blue (B) is applied to the surface of the dielectric layer exposed between the wall surfaces of the barrier ribs and the barrier ribs, and then dried and fired to phosphor layer Was made. The materials described above were used as the phosphor.

The produced front plate and back plate were bonded at 500 ° C. using a Bi—Zn—B—Si—O-based sealing glass. Then, after the inside of the discharge space was evacuated to a high vacuum (1 × 10 ⁻⁴ Pa), Ne—Xe-based discharge gas was sealed so as to have a predetermined pressure. In this way, a PDP was produced.

  It was confirmed that the produced panel operated without any problem without causing coloring or defects in the dielectric layer.

  The present invention can be suitably applied to the formation of a dielectric layer for covering insulating coating glass for electrodes, particularly display electrodes and address electrodes of PDPs.

The partial cutaway perspective view which shows an example of the structure of PDP by this invention Cross-sectional view of the PDP shown in FIG.

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 13 Phosphor layer 14 Discharge space

Claims (10)

At least B ₂ O ₃ , R ₂ O (R is one or more of Li, Na, and K) and Ln ₂ O ₃ (Ln is one or more selected from rare earth metals and Al), and B ₂ O _The glass composition is characterized in that the content of ₃ is 50 wt% or more and 95 wt% or less, and the content of Ln ₂ O ₃ is 0.2 wt% or more and 10 wt% or less. The glass composition according to claim 1, wherein Ln ₂ O ₃ is La ₂ O ₃ or Nd ₂ O ₃ . The glass composition according to claim 1, wherein Ln ₂ O ₃ contains Al ₂ O ₃ and a rare earth metal oxide at the same time. The glass composition according to claim 1, wherein R ₂ O is K ₂ O. The glass composition according to any one of claims 1 to 4, wherein a relative dielectric constant is 6.3 or less. A display panel in which an electrode is covered with a dielectric layer containing a glass composition, wherein the glass composition is the glass composition according to claim 1. A display panel comprising a first dielectric layer formed on a substrate, an electrode layer formed thereon, and a second dielectric layer formed thereon, wherein the first dielectric layer comprises: The display panel which is the glass composition of any one of Claims 1-5. A front substrate on which a first electrode and a dielectric glass layer are formed; a second substrate on which a dielectric glass layer and a phosphor layer are formed; and the first electrode and the second electrode. The front substrate and the rear substrate are disposed so as to face each other with a predetermined distance apart, and a partition is installed between the front substrate and the rear substrate, and the front substrate, the rear substrate, and A plasma display panel in which a dischargeable gas medium is sealed in a space formed by the partition walls, wherein at least a part of the dielectric glass layer on the first and second electrodes is formed according to claim 1. A plasma display panel, which is the glass composition according to any one of the above items. A front substrate on which a first electrode and a dielectric glass layer are formed; a second substrate on which a dielectric glass layer and a phosphor layer are formed; and the first electrode and the second electrode. The front substrate and the rear substrate are disposed so as to face each other with a predetermined distance apart, and a partition is installed between the front substrate and the rear substrate, and the front substrate, the rear substrate, and A plasma display panel in which a dischargeable gas medium is sealed in a space formed by the partition walls, wherein the partition walls include oxide glass, and at least a part of the oxide glass is defined in claim 1. A plasma display panel, which is the glass composition according to any one of the above items. A front substrate on which a first electrode and a dielectric glass layer are formed; a second substrate on which a dielectric glass layer and a phosphor layer are formed; and the first electrode and the second electrode. The front substrate and the rear substrate are disposed so as to face each other with a predetermined distance apart, and a partition is installed between the front substrate and the rear substrate, and the front substrate, the rear substrate, and A plasma display panel in which a dischargeable gas medium is sealed in a space formed by the barrier ribs, and the front substrate and the rear substrate are bonded with a sealing material, the sealing material including oxide glass A plasma display panel, wherein at least a part of the oxide glass is the glass composition according to claim 1.

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