JPS58142735A - Gas discharge display panel - Google Patents

Abstract

PURPOSE:To display clearly with a full contrast even under strong outdoor daylight by unifying the color of the whole surface of a display panel in a dark tone. CONSTITUTION:A transparent column electrode 4 independent every display column is provided inside of a frontal glass substrate 1, whereon a transparent dielectric layer 5 is formed. The transparent column electrode 4 is patterned in the shape of a tin oxide film or the so-called ITO film consisting of tin oxide and indium oxide, while the transparent dielectric layer 5 is given as the printed film of low melting point lead glass. Further, the blackened insulating layer 7 is provided on the dielectric layer 5 in the shape of demarcating a discharge cell 6 corresponding to a segment pattern of Japanese letter form ''?'' as a luminous part, whereby a dark color tone is given to the part excepting the luminous part of the display screen.

Description

Detailed Description of the Invention (α) Field of the Invention This invention relates to the improvement of display panels that utilize gas discharge, and particularly relates to a new indirect discharge type panel structure that can provide clear display with high contrast. It is.

(b) Background of the Invention There are display devices with a flat structure that utilize gas discharge, and among these, indirect discharge type display panels, which have a structure in which the discharge electrode is insulated from the gas discharge space, have a long life and high performance. Recently, there has been a tendency for it to be widely applied to outdoor applications because of its ability to provide brightness.

(C) Problems with the prior art However, in conventional gas discharge display panels of this type, one or both of the light-emitting and non-light-emitting parts are generally white, or the electrode material is metallic, which causes strong external light. When used under such conditions, the reflection is strong, and although the discharge brightness of the selected light-emitting portion is high, the contrast is reduced and the display becomes difficult to see. For this purpose, it is possible to apply a relatively dark filter to the display surface of the panel, but
Since the transmittance is low, it is difficult to avoid a decrease in overall brightness. Also, for example, column 4 43 of the Public Relations Publication No. 55-11262
As described in column 5, line 12, it is also known to improve the contrast by blackening the insulating layer (cell layer) formed in a predetermined pattern to fix the light emitting part in the gas discharge space. However, since the color tone of the light-emitting part remains the white color of the MgO protective film, there is a drawback that the contrast difference between the selective light-emitting part and the non-selective light-emitting part cannot be improved.

(d) Purpose of the Invention In view of the above-mentioned conventional situation, the object of the present invention is to provide a gas discharge display panel that can provide a clear display with sufficient contrast even under strong external light. be.

(b) Structure of the Invention Briefly stated, this invention is based on unifying the entire surface of the display panel in a dark color tone in order to achieve the above-mentioned purpose, and more specifically, , the dielectric layer for electrode coating on the rear glass substrate was darkened, and a dark insulating layer (cell layer) for defining the light emitting part of approximately the same color tone was provided on the dielectric layer for electrode coating on the entire glass substrate side. It is characterized by its configuration.

(f) Embodiment of the Invention FIG. 1 is a plan view showing the form of a display surface when the present invention is applied to a two-digit number display panel, and FIG. 2 is a sectional view of a main part thereof. In relation to both figures, a panel-shaped airtight container is constructed by airtightly sealing the periphery of a full-face glass substrate 1 and a rear glass substrate 2, which are arranged facing each other, with a sealing layer 3 made of low-melting glass, and the inside is heated to a predetermined pressure. The structure of filling the discharge gas to form a discharge panel is basically the same as the conventional one.

On the inner surface of the front glass substrate 1, independent transparent digit electrodes 4 are provided for each display digit, and a transparent dielectric layer 5 is formed thereon. The transparent spar electrode 4 is patterned in the form of a tin oxide film or a so-called ITO film made of tin oxide and indium oxide, and the transparent dielectric 5 is provided as a printed film of low melting point lead glass. Further, on the dielectric layer 5, an insulating layer 7 is provided which is blackened in the form of measuring discharge cells 6 corresponding to the "Japanese"-shaped segment pattern as light emitting parts. A black tone is given to the part.

The black insulator 7 has a segment pattern of discharge cells 6.
Since it defines the cell layer, it is usually called the cell layer. In order to make the cell layer 7 black, a coloring material such as cobalt oxide (Co2O3) may be mixed into the printing paste for forming the cell layer. As an example, Al2O
50g of powder from No. 3 and 44g of crystalline low melting point ship glass powder
A printing paste made by mixing 6 g of Co2O3 powder was printed on the transparent dielectric layer 5 to a thickness of about 50 μm and baked at 420° C. for 60 minutes, resulting in a dense black cell layer 7 with a good pattern. It was possible to form with precision.

On the other hand, on the inner surface of the rear glass substrate 2, rear segment electrodes 8 are provided in an arrangement corresponding to the segment pattern of the discharge cells 6, and a black dielectric layer 9 is coated thereon. The back segment electrode 8 is made of gold (Au), for example.
) or conductive paste such as iron (Ag) or nickel (Ni) in a predetermined segment pattern along with its lead parts. For example, it is made by printing and firing a paste to which Co2O3 is added. In this way, the inner surface of the rear glass substrate structure is given a black tone by the blackened dielectric layer 9, and when this is combined with the above-mentioned front glass substrate structure, the light emitting part (discharge cell part)
The color tone of the rear dielectric layer 9 appears in the area 6, and the color tone of the insulating layer (cell layer) 7 appears in the non-light emitting area, so that the color tone of the entire display surface is unified to black.

By the way, as in the above embodiment, the dielectric layer 5 for covering the electrode
When 9 and 9 are made of low-melting Kurofune glass, oxidation is applied to protect the surface of the dielectric layer from ion bombardment caused by discharge, and to increase the secondary electron emission coefficient of the discharge surface and reduce the operating voltage. It is common to provide a surface protection film 10 made of magnesium (MgO). However, this Mg
When the O protective film 10 is conventionally formed by a spray method, which is generally adopted from the viewpoint of workability, the color tone of the film is as white as the MgO powder, so the rear dielectric layer 9 is blackened. However, the effect of contrast improvement will be weak. Therefore, in order to improve not only the contrast between the light emitting part and the non-light end part, but also the contrast between the selective discharge segment and the non-selective segment between the light emitting segments, it is necessary to make the color tone uniformity effect of the rear black dielectric layer 9 appear.
It is necessary to increase the coating density of the gO protective film 10 or form it into a transparent film. In this point, if MgO is deposited on the dielectric layers 5 and 9 by electron beam evaporation, transparent MgO can be easily formed.
It is possible to obtain a film, and it is possible to achieve a protection function for the surface of the dielectric layer and a further improved function of lowering the voltage without impairing the effect of unifying the color tone of the panel display surface.

Furthermore, when the cell layer 7 and the rear dielectric layer 9 are blackened as described above, it becomes difficult to visually align the image glass substrate values. Therefore, when adopting this invention, when forming electrodes on both substrates, an alignment pattern is printed at a predetermined position on each substrate using a conductive paste for electrodes, and then the alignment pattern described above is formed without the alignment pattern portion. A black cell layer 7 and a back dielectric layer 9 are formed. In FIG. 1, phase number 11 indicates this alignment pattern, and although neither the black cell layer nor the black rear dielectric layer is applied to this part, the alignment pattern position is located between the girders and away from the light emitting part. Since it is located on the outer periphery of the panel and is small, even if the color tone differs in this area, it has almost no effect on the contrast of the display.

In the configuration shown in FIG. 2, a spacer layer 12 is provided on the black dielectric layer 9 on the rear glass substrate 2 side in order to define the discharge gap. This spacer layer 12 is
It is printed in a predetermined pattern so as to partially abut against the opposing black cell layer 7 and define the gap size of the discharge cells 6 in the light emitting segment arrangement, so as not to impede the flow of gas between the cells. It is preferable that the material of the spacer layer 12 is also black in order to unify the color tone of the panel, and for this purpose it is convenient to use the same material as the cell layer 7. Furthermore, in this invention, it is recommended to blacken the sealing layer 3 that seals the two glass substrates 1 and 2, and for this purpose, a small amount of low-point glass paste for sealing is added. It is sufficient to mix in a coloring additive, that is, several percent of Co2O3. In this way, the color tone of the panel surface is unified to black, and the reflection of external light can be significantly reduced.

In the above example, although it was described that the color tone of the panel was unified to black, the main objective was to reduce the reflection between the light-emitting part and the non-light-emitting part, and to eliminate the difference in reflectance between them. Therefore, the color tone is not limited to black, but any dark color is sufficient.

Further, the present invention is applicable not only to a gas discharge panel for displaying numbers as shown in the figure, but also to panels having other identification display patterns and panels having a matrix electrode structure.

(g) Effect of the invention As is clear from the above explanation, in short, this invention:
This feature is characterized in that the color tone of the light-emitting and non-light-emitting areas in the panel display image is unified to a dark color tone, which is extremely advantageous in preventing reflection of external light and improving contrast. Therefore, the gas discharge display panel according to the present invention can provide a clear display with sufficient contrast even when used outdoors under strong external light.

[Brief explanation of the drawing]

FIG. 1 and FIG. 2 are a plan view and a sectional view of a main part of the structure of an embodiment of a numerical display gas discharge panel to which the present invention is applied. 1: Front glass substrate, 2: Rear glass substrate, 3: Sealing layer, 4: Transparent digit electrode, 5: Transparent dielectric layer, 6: Discharge cell as light emitting part, 7: Black insulating layer, (cell layer) , 8: back segment electrode, 9: black dielectric layer, 10: MgO protective film, 11: alignment pattern, 12 = spacer layer.

Claims (2)

[Claims] (1) A front glass substrate having a transparent electrode covered with a transparent dielectric layer and a rear glass substrate having a back electrode covered with a dark dielectric layer are arranged facing each other with a discharge gas space interposed therebetween, and A gas discharge display panel characterized in that a dark-colored insulating layer exhibiting substantially the same color tone as the dielectric layer on the rear glass substrate side is formed on a transparent dielectric layer corresponding to a non-light-emitting portion of a front glass substrate. (2) The gas discharge display panel according to claim 1, wherein a transparent surface protection film is provided on the dark dielectric layer of the cross-sectional glass substrate.