JPH04298936A - Plasma display panel - Google Patents

Abstract

PURPOSE:To improve contrast by providing stereoscopic structures at portions corresponding to gaps between picture elements of a panel display face. CONSTITUTION:Eaves 9 are provided on the surface of a front substrate 7. The eaves 9 are stereoscopic structures with the width equal to about the gap of dots and the height of the picture element size formed by screen printing at portions of bulkheads 4. The light of a ceiling lamp among the indoor light 20 scattered by phosphors 8 to reduce contrast is shielded by the eaves 9 at the incidence angle 45 deg. or above against a plasma display panel face, thus most of the light is shielded. The luminescence of the phosphors 8 transmits the substrate 7 and no filter, the intensity is not reduced, and the contrast is increased. When the eaves 9 are formed only above and below picture elements, the right and left visual field angle is not affected at all. The contrast can be improved without reducing the intensity.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to plasma display panels used in information processing terminals, flat-panel televisions, and the like.

0002

[Prior Art] Color plasma display panels display colors by exciting phosphors to emit light using ultraviolet light generated by electric discharge, but since the phosphors are usually white powders, they scatter indoor light and cause the screen to blur. The image becomes whitish and the contrast decreases. To solve this problem, there is a way to attach a filter to the surface. Although this method improves contrast, it has the disadvantage that brightness is significantly reduced. Figure 3 shows this method. Here, an AC surface discharge type is taken as an example, but the same applies to other types. The electrode 5 formed on the rear substrate 1 is covered with an insulating layer 2 and further covered with a protective layer 3. Further, a phosphor 8 is formed on the front substrate 7, and the two substrates are pasted together and hermetically sealed via the partition wall 4, and the discharge space 6 is filled with a dischargeable gas, usually a mixed gas of He and Xe. A filter 11 is formed on the panel surface to improve contrast. A pulsed voltage is applied between adjacent electrodes 5 to generate a discharge between the electrodes. The ultraviolet light generated by the discharge excites the phosphor 8 and causes the phosphor to emit light 2.
Get 1.

Room light 20 incident on the panel surface passes through the filter 11, hits the phosphor 8, is scattered, and passes through the filter again to exit the panel. On the other hand, the emitted light 20 of the phosphor passes through the filter once and exits the panel. If the transmittance of the filter 11 is 50%, indoor light passes through the filter twice and is attenuated to 25%, but the light emitted from the phosphor passes through the filter only once, so the attenuation is 50%.
%, thus the contrast is improved by a factor of two. However, the brightness will be halved.

[0004]Also, there is a method of forming a color filter that transmits only the emitted color for each pixel, but the process is complicated and costly, and a certain degree of reduction in brightness is unavoidable.

[0005]

[Problem to be solved by the invention] In order to prevent indoor light from being scattered by phosphors and the contrast being lowered, it is possible to use a filter, but this results in a significant decrease in brightness, and color filters also reduce brightness to some extent and are costly. The problem is that there is a significant increase in

[0006]

[Means for Solving the Problems] The plasma display panel of the present invention is provided by providing a three-dimensional structure on the surface of the panel on the display surface side of the panel in a portion corresponding to the gap between each pixel, and on the display surface side of the panel. By making at least the part corresponding to each pixel of the board transparent and the remaining part black, indoor light from above the panel, especially light from ceiling lights, is prevented from entering the phosphor, thereby reducing the brightness. It is possible to significantly improve contrast without reducing it.

[0007]

[Operation] The plasma display panel of the present invention has a three-dimensional structure on the surface of the panel on the display surface side in a portion corresponding to the gap between each pixel, so that indoor light from above the panel, especially light from ceiling lights, can be absorbed. This prevents the light from entering the phosphor. Among the indoor lights that reduce the contrast of the panel, the most problematic light is the light from ceiling lights that enters from above the panel. By providing a three-dimensional structure between each pixel, this serves as an eaves and blocks the light from the ceiling light. Also, since no filter is used, there is no reduction in brightness.

In another plasma display panel of the present invention, at least a portion of each pixel of the substrate on the display surface side is made transparent, and the remaining portion is made black, so that the black portion serves the same role as the above-mentioned eaves. , it is possible to reduce the incidence of indoor light on the phosphor and improve contrast without reducing brightness.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS A first embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a sectional view of a plasma display panel according to an embodiment of the present invention. The principle of light emission is the same as that explained in the conventional example. An eaves 9 is provided on the surface of the front substrate 7. The eaves 9 are the gaps between the phosphor dots, that is, as shown in the figure.
A three-dimensional structure whose width is about the width of a dot gap and whose height is about the size of a pixel is formed on a certain part of the partition wall 4 by, for example, screen printing. Of the indoor light 20 that is scattered by the phosphor 8 and reduces the contrast, the most problematic light is the light from the ceiling light. If the eaves 9 have the same height as the pixel size, the eaves 9 will block indoor light entering the plasma display panel from an angle of incidence above 45°, and in particular most of the light from ceiling lights will be blocked. On the other hand, the light emitted from the phosphor 8 is transmitted through the front substrate 7, and since there is no filter, the brightness does not decrease. Therefore, the contrast is significantly improved. Furthermore, if the eaves 9 are formed only above and below the pixels, the left and right viewing angles are not affected at all.

FIG. 2 shows a second embodiment of the invention. The panel structure is the same as in the above embodiment, except that an eaves substrate 12 on which an eaves 9 is formed is provided on the front substrate. The width, height, and position of the eaves 9 are the same as in the above embodiment. As a result, the eaves 9 can be formed on the eaves substrate 12, so that it can be manufactured separately from the front substrate and can be bonded to the front substrate at the end. Therefore, the manufacturing process is also simplified. The eaves substrate 12 also serves as a protective film for the eaves 9.

As explained above, according to the present invention, contrast can be significantly improved with a very simple structure without reducing brightness.

Next, a third embodiment of the present invention will be described with reference to the drawings. FIG. 4 is a cross-sectional view of an embodiment of the invention. The panel structure is the same as the conventional example, but the front substrate 7 is different. If a portion of the front substrate 7 corresponding to each pixel is transparent and the remaining portion is a black portion 13, the indoor light 20 is reflected in the black portion 13.
This makes it difficult for the light to enter the phosphor 8. Therefore, the contrast is improved as in the previous embodiment. The thickness of the front substrate 7 is usually about 2 mm, so if the refractive index of the glass is 1.4, indoor light with an incident angle of 45° or more can be completely prevented from entering the phosphor when the pixel size is 1 mm or less. The front substrate 7 is manufactured by, for example, forming a black portion 13 on a glass substrate by screen printing, filling the gap with transparent glass powder, and firing the black portion 13 . Then, the glass substrate is polished and removed. This made it possible to improve contrast without reducing brightness. Here, the glass substrate may be left as is without being polished and removed. This case is shown in FIG. 5 as a fourth embodiment. The black part 13 in FIG. 4 of the third embodiment does not need to be continuous in the thickness direction of the front substrate 7, and the effect can be obtained even if it is only a part like the black part 13 in FIG. This simplified the manufacturing process.

[0013]Although all of the above explanations have been made using a color plasma display panel as an example, the present invention can be applied to all displays that emit light from phosphors. Therefore, similar effects can be obtained with fluorescent display tubes and CRTs. Moreover, it can be used not only for color plasma displays but also for monochrome plasma displays.

[0014]

[Effects of the Invention] According to the present invention, contrast can be improved with a simple structure without reducing brightness.

[Brief explanation of drawings]

FIG. 1 shows a sectional view of a first embodiment.

FIG. 2 shows a cross-sectional view of a second embodiment.

FIG. 3 shows a cross-sectional view of a conventional color plasma display panel.

FIG. 4 shows a cross-sectional view of a third embodiment.

FIG. 5 shows a cross-sectional view of a fourth embodiment.

[Explanation of symbols]

1 Rear board 2 Insulating layer 3 Protective layer 4 Bulkhead 5 Electrode 6 Discharge space 7 Front board 8. Phosphor 9 Eaves

Claims (2)

[Claims] 1. A plasma display panel in which a phosphor coated inside a panel formed by laminating two substrates together and hermetically sealed is excited to emit light by discharging a gas filled inside the panel, comprising: A plasma display panel characterized in that a three-dimensional structure is provided in at least a part of the panel surface on the display surface side corresponding to the gap between each pixel. 2. A plasma display panel in which a phosphor coated on the inside of a panel formed by laminating two substrates together and hermetically sealed is excited to emit light by discharging a gas filled inside the panel. A plasma display panel characterized in that at least a portion of the substrate on the display surface side corresponding to each pixel is transparent, and the remaining portion is black.