JPH0447639A - Color discharge display panel - Google Patents

Abstract

PURPOSE:To improve reflecting efficiency under a phosphor and lower the manufacturing cost and heighten the display brightness by forming a reflecting layer of a white pigment powder on at least a back side substrate of the inner walls of a discharge cell and forming a phosphor layer on the reflecting layer. CONSTITUTION:A writing electrode 7 is formed on a glass back side substrate 1 first. After that, a paste consisting of titanium oxide fine powder with average grain size 0.3mum, a binder, and a solvent is printed by screen printing into prescribed dots to form a white pigment layer 9. After it is dried at 120 deg.C, a paste consisting of a blue-emitting phosphor powder, a binder, and a solvent is printed on one third of the dots of the titanium oxide by screen-printing and dried to form a phosphor layer 10a. Further, a paste containing green- emitting phosphor powder and a paste containing red-emitting phosphor powder are printed on one third of the dots, respectively, in different position to form phosphor, layers 10b and 10c.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a color discharge display panel used for information display and television image display, and particularly to a color discharge display panel with improved luminance.

[Prior Art] Discharge display panels use gas discharge to display luminescent light, and have excellent features such as large nonlinear discharge phenomena, high-speed response, and a unique memory effect. Widely used in information display devices, etc. At present, the main ones that have been put into practical use are single-color red-orange displays based on Ne discharge luminescence, but fluorescent materials coated on the inner walls of discharge cells using a discharge gas that generates ultraviolet light such as XE. By converting the light into visible light such as red, green, and blue, full-color display can be realized.

Such color discharge display panels have various structures, and can be classified into transmissive type and reflective type based on the coating position of the phosphor powder. The transmissive type is a panel in which a phosphor is coated on the front substrate side that serves as the display surface, and the luminescent display is viewed through the phosphor layer. On the other hand, in the reflective type, a phosphor is coated on the back substrate on the back side of the display and on the inner wall of the barrier rib portion for separating the discharge cells. The reflective type allows you to see the light emitted by the phosphor directly through the transparent front substrate.
The dot brightness is higher than that of the transmissive type, and if some idea is taken to increase the aperture ratio, it is more advantageous than the transmissive type.

However, even in such a reflective type, the light generated from the phosphor is radiated in all directions, so the light that is extracted to the display side and contributes to the display is considerably reduced. In order to improve this problem, a method of using a white glaze layer is being used.

FIG. 3 is a partial sectional view of a panel showing an example of a reflective type. A white glaze layer 36 and a phosphor layer 35 are formed on the rear substrate 31. Discharge cells 33 defined by front substrate 32 and barrier ribs 34 are formed.

The discharge cell 33 is filled with a discharge gas containing xe.

The electrode structure may be a DC type or an AC type using an electrode covered with a dielectric layer. In addition, there are various types such as a surface discharge configuration and a 1-pixel 3-electrode structure.
FIG. 3 shows an example in which the electrodes are omitted for the sake of simplification because they are not directly related to the structure.

The phosphor layer 35 generates visible light due to the ultraviolet rays generated by the discharge. The light radiated upward from the phosphor layer 35 is effectively taken out as display light, but if the phosphor layer 35 does not have the white glaze layer 36, the light radiated downward is almost directly emitted to the back surface and does not contribute to display. . When there is a white glaze layer 36 as shown in FIG. 3, part of the light is diffused and returned to the display side, resulting in improved brightness. Such a white glaze layer is mainly composed of lead glass with a low softening point, in which fine powder such as alumina or titanium oxide, which has a different refractive index from the glass component, is dispersed, and is formed by screen printing. Note that this white glaze layer is A
A C-type dielectric layer or a glaze layer formed as an interlayer insulating layer of a multilayer electrode structure is often whitened to provide a diffuse reflection function.

[Problems to be Solved by the Invention] As described above, display brightness can be improved by disposing a white glaze layer under the phosphor layer.
There is still a lot of wasted light emitted to the rear side, and the improvement effect is not sufficient. This is due to the fact that the white glaze layer has poor anti-fouling properties.

Factors that determine the performance of such diffusion fouling include the difference in refractive index between the dispersed powder and the glass medium, the particle size of the dispersed powder, and the packing density. In the white glaze layer, the refractive index of lead glass is 1.
Since it is quite large, about 7, it is difficult to obtain a large difference in refractive index from the dispersed powder. Furthermore, if the amount of dispersed powder is increased, reflow will not occur even at the firing temperature and a good layer cannot be formed, so the amount of powder mixed cannot be increased.

For these reasons, the reflectance of the white glaze layer is necessarily unobtrusive, and the brightness improvement is not sufficient. Furthermore, regardless of whether the white glaze layer is used as a dielectric layer or the like of an AC type panel, if it is newly formed as a nonconforming layer, there is a problem in that the manufacturing process is greatly increased.

The present invention was made in response to the above-mentioned conventional circumstances, and an object of the present invention is to provide a color discharge display panel with improved reflectance below the phosphor, low manufacturing cost, and high display brightness. do.

[Means for Solving the Problems] The present invention provides a color discharge display panel including discharge cells defined by partition walls between a rear substrate and a front substrate serving as a display side. The color discharge display panel is characterized in that a reflective layer made of white pigment powder is formed on the panel, and a phosphor layer is formed on the reflective layer.

[Function] The diffuse reflection layer formed under the phosphor layer of the present invention is made of white pigment fine powder. As this white pigment, various oxides such as titanium oxide, barium oxide, lead oxide, magnesium oxide, and aluminum oxide, sulfides such as zinc sulfide, and white fine powders of nitrides and fluorides can be used. . Among these, titanium oxide is the most practical because it has a high refractive index, is inexpensive, and can be produced manually. Unlike the white glass layer, this white pigment layer is simply a powder layer, so it has a large refractive index difference with the refractive index of the discharge gas (approximately 1), and it cannot be made into a densely packed fine powder layer. Because of this, it has high reflective performance. Further, such a structure can be easily realized by applying white pigment powder in a similar manner before applying the phosphor powder.

[Example] Next, embodiments of the present invention will be described in detail.

FIG. 1 is a partial cross-sectional view of an example of a color discharge display panel according to the present invention. In this method of manufacturing a discharge display panel, first, a write electrode 7 is formed on a back substrate 1 made of glass. Thereafter, a white pigment layer 9 was formed by screen printing a paste 1 consisting of fine titanium oxide powder having an average particle size of 0.3 IIn, a binder, a solvent, etc. in a predetermined dot shape. This is 12
After drying at 0°C, blue phosphor powder (BaMqAf!14
A paste consisting of O23'Eu), a binder, a solvent, etc. was screen printed on the 1/3 titanium oxide drum 1 and dried to form a phosphor layer 10a.

Furthermore, green phosphor powder (Zr)2S+04:Mn)
pace i~ and red phosphor powder ((Y,Gd)BO
3: Fu) paste] was printed on each of the titanium oxide 1 to 1/3 by shifting the position in the same manner as the blue phosphor powder to form phosphor layers 10b and 10c. This substrate is fired at 500°O to remove the binder component and form a white pigment layer 9 of titanium oxide and blue and green.

A rear substrate portion on which red phosphor layers 10a to IOC were formed was completed. The thickness of each phosphor layer is approximately 107/g!
child.

On the other hand, a surface discharge electrode 6 designed to have a sufficient opening is formed on the front substrate 2, and a glass layer formed by thick film technology and a magnesium oxide surface protection film formed by vacuum evaporation are formed on the surface discharge electrode 6. A dielectric layer 8 consisting of layers is formed. A center sheet glass plate with many minute holes was sandwiched between the front substrate part and the rear substrate part as a partition wall 4, and discharge cells 3 were formed and the panels were stacked against each other to complete the panel. A He-Xe mixed gas containing 1% of Xe was sealed as a discharge gas. When this panel was turned on, the white surface brightness was 11.
A brightness of 0 Cd/= was obtained.

On the other hand, when a panel without the white pigment layer 9 was prepared and the brightness was measured under the same driving conditions as above, it was found to be 75 Cd/m
The effect of the white @paddy layer was confirmed. If the white pigment layer of titanium oxide is thin, the reflection effect will be small, and if it is thick, the reflection performance will be saturated, which will cause manufacturing problems, so it is preferable to keep it in the range of 1 to 30 layers.

FIG. 2 is a partial sectional view of a panel showing a second embodiment in which a white pigment layer and a phosphor layer are also formed on the partition walls. This panel is structurally almost the same as that shown in FIG. 1, but in this embodiment, barrier ribs 24 are directly formed on the rear substrate 21 to form discharge cells 23. The partition wall 24 is a black insulator made by mixing low melting point glass with fine powder such as aluminum oxide or iron oxide, and is formed by thick film technology. On top of this, pastes 1 to 1 consisting of fine titanium oxide powder, a water-insoluble binder, etc. were applied uniformly over the entire surface and dried. After this,
Photosensitive pastes 1 to 1 consisting of phosphor powder, PVA, etc. were applied, and drying, exposure, and development were repeated for blue, green, and red phosphors, and then baking was performed at 500'C.

The discharge cell 23 thus obtained has a white pigment layer 29 and a phosphor layer 25a also on the partition wall portion of the rear substrate portion.

Since 25b and 25c are formed, even higher brightness can be obtained.

Although titanium oxide powder was used as the white pigment layer in the above embodiments, other materials may be used as long as they are white powders with a high refractive index. Furthermore, in order to improve the adhesion strength of the white pigment layer, a small amount of a glass component may be mixed in to bridge the particles.

[Advantageous Effects of the Invention 1] As explained above, according to the present invention, a color discharge display panel with improved emission brightness of a color plasma display is provided. In addition, since the discharge display panel of the present invention can form the fouling layer in the same process as applying the phosphor powder layer, no new installation is required, and the process is simple, so there is no impact on cost. There are few. Further, according to the configuration of the present invention, it is possible to make the phosphor layer thinner, and there is also an advantage that the amount of expensive phosphor material used can be reduced.

[Brief explanation of the drawing]

1 and 2 are partial sectional views of an embodiment of the present invention, and FIG. 3 is a partial sectional view of an example of a color discharge display panel according to the prior art. 1, 21.31... Rear substrate 2, 22.32... Front substrate 3. 23.33... Discharge cell 4, 24.34... Partition wall 6. 26... Surface discharge electrode 7. 27...Writing electrode 8.28...Dielectric layer 9.29...White pigment layer 10a, 10b, 10c, 25a, 2
5b, 25c, 35...phosphor layer 36...white blaze layer

Claims (1)

[Claims] (1) In a color discharge display panel equipped with a discharge cell defined by a partition between a rear substrate and a front substrate serving as a display side, a reflective layer made of white pigment powder is provided on at least the rear substrate on the inner wall of the discharge cell. 1. A color discharge display panel comprising: a phosphor layer formed on the reflective layer; and a phosphor layer formed on the reflective layer.