JPH10302648A - Glass substrate for plasma display - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enhance the luminance or contrast of image display and minimize the yellowing of a substrate glass which is a problem on display by forming an insulating metal oxide film capable of preventing the dispersion of Ag ion to the substrate glass surface on the substrate glass. SOLUTION: Two parallel display electrodes of an X-electrode 5 and a Yn electrode 6 are formed on a glass substrate 10 for plasma display in a number of pairs, each of the display electrodes 5, 6 is formed of a transparent electrode 8 and a bus electrode (metal electrode) 9, and an ac voltage is applied between these parallel electrodes to perform a surface discharge. A dielectric layer 3 and a protecting layer 4 (MgO) are provided on the display electrodes 5, 6. The glass substrate 10 is formed of a front glass substrate 1 and an insulating metal oxide film 2, and the metal oxide film 2 is formed of at least one selected from the group consisting of SiO2 , ZrO2 , Al2 O3 and TiO2 . The yellowing of the substrate glass 1 by Ag ions generated according to surface discharge can be minimized.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to a glass substrate for a plasma display.

[0002]

2. Description of the Related Art Conventionally, as a glass substrate for a plasma display, soda lime silicate glass formed into a plate having a thickness of 1.5 to 3.5 mm or glass having a higher strain point has been used. I have. Usually, the substrate glass is formed by a float method excellent in smoothness and suitable for mass production.

[0003]

In the float method, since the glass surface is exposed to a hydrogen atmosphere during the molding process, a reduced layer of several microns is formed on the glass surface. Therefore, in the plasma display manufacturing process, when silver is applied as an electrode to the surface of the substrate glass via a transparent electrode and baked, silver ions pass through the transparent electrode by diffusion, reach the glass surface, are reduced by the reduction layer, and are reduced by metallic silver. The present inventors have found that a colloid is produced. The silver colloid causes the substrate glass to be colored yellow, which is an obstacle to improving brightness and contrast of image display. In addition, it has been found that there is a problem in that the entire panel appears to be colored yellow, which reduces the commercial value.

As described in Japanese Utility Model Publication No. 6-34341, the problem of silver paste as an electrode coloring the substrate glass is that a silver electrode for a deflow star provided on a rear window glass of an automobile is made of glass. It is known for the phenomenon of coloring the substrate. As a countermeasure, a reducing agent, which is a metal powder, is placed in a colored ceramic layer applied between the silver electrode and the substrate to prevent silver in the silver paste from being ionized. There is known a method of preventing silver from diffusing in a colored ceramic layer to prevent coloring of a glass substrate.

[0005] Such a method is not suitable for use in a glass substrate for a plasma display, which requires high precision smoothness.

[0006]

Means for Solving the Problems The present inventors have studied the above-mentioned problems, and have found that by using a substrate in which a certain kind of metal oxide is formed as a protective film on the glass surface, a yellow color due to silver colloid is obtained. Have been found to be able to be significantly reduced, leading to the present invention.

That is, according to the present invention, Ag
Provided is a glass substrate for a plasma display having an insulating metal oxide film capable of preventing ⁺ ions from diffusing into a substrate glass surface.

The present invention provides a glass substrate for a plasma display having a silver layer formed by firing silver via an insulating metal oxide film on a substrate glass and having a yellowness b ^* of 15 or less on the substrate surface. .

Provided is a glass substrate for a plasma display having an insulating metal oxide film that can have a yellowness b ^* of 15 or less on the surface of a substrate when silver is applied and baked on the glass substrate.

[0010] the composition of wherein said substrate glass, SiO ₂ 50-72 wt% Al ₂ O ₃ 0 to 15 wt% R ₂ O 6 to 24 wt% R'O 6 to 24 wt% (wherein R is R ′ represents at least one selected from the group consisting of Li, Na and K, and R ′ is Mg, Ca, S
represents at least one selected from the group consisting of r, Ba and Zn. )) Is preferred.

The insulating metal oxide film is made of SiO ₂ , Z
A glass substrate for a plasma display which is at least one selected from the group consisting of rO ₂ , Al ₂ O ₃ and TiO ₂ is preferred.

[0012]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to preferred embodiments shown in the drawings, but the present invention is not limited to these embodiments.

The panel of the color plasma display is
There is a glass substrate 10 on the display surface side shown in FIG. 1 and a glass substrate on the back side (not shown) opposed to this. An X electrode 5 is provided on the glass substrate on the display surface side shown in the drawing.
Many pairs of two parallel display electrodes of the Yn electrode 6 are formed. Each display electrode includes a transparent electrode 8 and a bus electrode (metal electrode) 9. An AC voltage is applied between the parallel electrodes to perform surface discharge. Dielectric layer 3 on display electrode
And a protective layer (MgO) 4. On the other hand, although not shown, address electrodes are formed on the glass substrate on the rear side opposite thereto, in the direction orthogonal to the display electrodes, and red (R) green (G) blue (B) provided near the electrodes Is colored as one pixel. As the electrodes used in these plasma displays, electrodes mainly composed of silver such as silver paste are used. The glass substrate 10 of the present invention shown in FIG.
It comprises a front glass substrate 1 and an insulating metal oxide film 2.

The glass substrate for a plasma display of the present invention is not limited to the panel structure described in the above configuration, but may be any as long as a silver paste is fired on its surface. The silver paste may be formed on the substrate via a transparent electrode as shown in FIG. 1, or may be formed directly on the substrate. Further, not only the glass substrate on the display surface side having the transparent electrode shown in FIG. 1 but also a glass substrate for a back plate (not shown) may be used.

With respect to the base composition of the substrate glass, SiO ₂ 50 to 72, Al ₂ O _{3
0~15, R 2 O 6~24, R'O} 6
To 24, wherein R represents at least one selected from the group consisting of Li, Na and K, and R ′ is Mg, C
represents at least one selected from the group consisting of a, Sr, Ba and Zn. ) Is preferable.

In this composition range, the strain point is 550 ° C. or higher, and the coefficient of thermal expansion at 0 to 300 ° C. is 70 × 10 ^{-7 to} 90.
A substrate glass having a ^{density of 10-7} / C is obtained. A glass substrate having a strain point of 550 ° C. or higher is preferable because irregular thermal deformation and large thermal shrinkage hardly occur in a firing step in manufacturing a plasma display substrate. Also, 0-30
The coefficient of thermal expansion at 0 ° C. is 70 × 10 ^{−7 to} 90 × 10 ⁻⁷ / ° C.
Such a substrate glass is preferable because it has a coefficient of thermal expansion that matches that of a glass frit that is generally used as a member of a plasma display panel, and thus does not easily cause problems such as deformation when manufacturing the plasma display panel.

The front glass substrate 1 is usually formed by a float method in a reducing atmosphere. The insulating metal oxide film 2 provided on the front glass substrate 1 is for preventing Ag ⁺ ions from diffusing to the surface of the front glass substrate 1 in the glass substrate 10 for a plasma display of the present invention. When a silver paste is applied as a silver electrode and baked at 580 ° C., the diffusion of Ag ⁺ ions into the front glass substrate is restricted because the insulating metal oxide film 2 is present between the silver paste and the front glass substrate 1. In addition, it is possible to prevent metallic silver AgO from being formed on the glass surface and becoming a colloid, whereby the glass substrate is colored yellow.

The extent to which the diffusion of Ag ⁺ ions into the surface of the front glass substrate 1 can be prevented, for example, by changing the color tone when silver is applied to the surface of the insulating metal oxide film 2 and baked at 580 ° C. for 1 hour. Is less than or equal to 15 in yellowness b ^* .

As the metal oxide film, SiO ₂ , Zr
O ₂ , Al ₂ O ₃ , TiO _{2 and the} like are exemplified, and these may be used alone or as a mixture. Although the film thickness is not particularly limited, the effect of preventing silver ions from diffusing into the substrate increases as the film thickness increases. Glass substrate 1 on the display surface side for plasma display
Since 0 is required to have transparency, it is preferably about 10 to 100 μm, and more preferably about 100 to 2000 °.

The method of manufacturing the glass substrate 10 for a plasma display according to the present invention is performed on the front glass substrate 1 manufactured by a float method or the like by, for example, a known method such as a sputtering method, a CVD method, a dip method, or a vapor deposition method. An insulating metal oxide film 2 is formed. The insulating metal oxide film 2 may be formed directly on the surface of the front glass substrate 1, or may be formed via another film or layer if necessary. Silver present as the plasma display glass substrate 10 directly on the insulating metal oxide film 2 or through another film or layer such as a dielectric layer is diffused as Ag ⁺ ions to the surface of the front glass substrate 1. May be present between the silver layer and the front glass substrate 1 so as to prevent the occurrence of blemishes.

For example, the front glass substrate 1 is immersed in a solution obtained by diluting silicon hydroxide, silicon hydroxide and aluminum hydroxide or titanium chloride in a solvent mainly composed of alcohol, pulled up, and fired to form a silicon oxide film, A mixed film of silicon and aluminum oxide or a titanium oxide film is formed. Alternatively, a silicon oxide film is formed by performing electron beam evaporation using silicon dioxide as an evaporation source at a pressure of 1 × 10 ⁻⁵ torr or less.

The formation of the silver layer serving as the bus electrode 9 is not particularly limited, but may be, for example, 70 to 80 wt% of silver powder, 3 to 5 wt% of frit (low melting point lead glass), or 27 to 15 wt% of a vehicle in which oil and resin are mixed. A silver paste having a composition is applied in a predetermined shape, dried, and then dried at a predetermined temperature, for example, 50 ° C.
By baking at 0 to 600 ° C., the bus electrode 9 is formed on the transparent electrode 8. The transparent electrode 8 is usually formed of ITO or SnO ₂ to a thickness of 400 to 5000 ° by a sputtering method, a CVD method, a vacuum evaporation method, a pyrosol method, a sol-gel method, or the like.

[0023]

EXAMPLES The present invention will be described below with reference to examples, but the present invention is not limited to these examples. An SiO ₂ film was formed on the surface of the soda lime silicate glass and the glass substrate for PDP formed by the float method by the CVD method, the sputtering method, and the dipping method. afterwards,
2000Å formed by sputtering on the film on the glass surface
A silver paste (NP4002, manufactured by Noritake Co., Ltd.) was printed through a transparent electrode made of thick ITO, and baked at 580 ° C. for 1 hour. The color tone of the glass surface observed from the opposite side of the printing surface was measured by a commercially available colorimeter. The SiO ₂ film formed by the dipping method was formed by immersing the substrate glass in an aqueous solution of silicon alkoxide, pulling it up at a constant speed, and baking it at 400 ° C. The results are shown in Table 1.

Examples 1 to 5 in Table 1 show the composition of the glass substrate, the method of forming the protective film, the thickness of the protective film, and the color tone of the substrate surface due to the colloid. The mother glass composition in Table 1 is
It is as shown in Table 2. The color tone of the substrate surface is represented by an L ^* a ^* b ^* color system using a C light source. Examples 6 and 7 in Table 1 are comparative examples, and show the results of performing similar measurements without attaching any film to the glass substrate. Thus, it can be seen that in Examples 1 to 5 of the present invention, silver colloid color development was suppressed, and b ^* representing the degree of yellowness was smaller than in Comparative Examples 6 and 7.

[0025]

[Table 1]

[0026]

[0027]

According to the present invention, it is possible to obtain a glass substrate for a plasma display which has high brightness and contrast of pixel display and has a small yellow color which causes a problem in display.

[Brief description of the drawings]

FIG. 1 is a sectional view of a glass substrate for a plasma display of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Front glass substrate 2 Insulating metal oxide film 3 Dielectric layer 4 Protective layer 5 X electrode 6 Yn electrode 8 Transparent electrode 9 Bus electrode (metal electrode) 10 Glass substrate for plasma display

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁶ Identification code FI H01J 17/16 H01J 17/16

Claims (3)

[Claims] 1. A glass substrate for a plasma display having an insulating metal oxide film on a substrate glass capable of preventing diffusion of Ag ⁺ ions to the surface of the substrate glass. Wherein the composition of the substrate glass, SiO ₂ 50-72 wt% Al ₂ O ₃ 0 to 15 wt% R ₂ O 6 to 24 wt% R'O 6 to 24 wt% (wherein R is R ′ represents at least one selected from the group consisting of Li, Na and K, and R ′ is Mg, Ca, S
represents at least one selected from the group consisting of r, Ba and Zn. The glass substrate for a plasma display according to claim 1, wherein 3. The insulating metal oxide film is made of SiO ₂ , Z
The glass substrate for a plasma display according to claim 1, wherein the glass substrate is at least one selected from the group consisting of rO ₂ , Al ₂ O _3, and TiO ₂ .