JPH11260269A - Plasma display device and substrate for plasma display - Google Patents

Abstract

(57) Abstract: In a plasma display device, the contrast when external light is reflected is improved without lowering the brightness of the screen. A light control plate is provided between a cavity and a surface glass substrate. The surface of the light control plate 4 facing the cavity 17 is a high-reflectance surface 5 that totally reflects light, and the opposite surface is a light-absorbing surface 6. The transmission hole 7 is opened.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a plasma display device and a plasma display substrate.

[0002]

2. Description of the Related Art (First Conventional Example) Generally, liquid crystal display devices and plasma display devices are known as image display devices. Among them, the plasma display device is
It has features such as thinness, light weight, and a wide viewing angle, and is a promising device for large wall-mounted TVs for home use along with liquid crystal display devices.

FIG. 1 shows the structure of a plasma display panel. The plasma display panel 10 is a self-luminous type. As shown in FIG. 1, a cavity (cell) corresponding to a pixel is provided between the inner surfaces of a front glass substrate 11 and a back glass substrate 12.
17 are formed, and each cavity 17 is partitioned by the partition wall 13. A region of the inner surface of the cavity 17 other than the inner surface of the surface glass substrate 11 is a phosphor-coated surface, and the entire surface of the phosphor-coated surface is coated with the fluorescent paint 15. A low-pressure gas is sealed in the cavity 17, and an anode electrode 20 and a cathode electrode 22 for applying a voltage to the low-pressure gas are provided on the inner surface of the back glass substrate 12 and the inner surface of the front glass substrate 11, respectively. Then, when a voltage is applied to the low-pressure gas by the anode electrode 20 and the cathode electrode 22, the fluorescent paint 15 emits light by ultraviolet rays generated by the gas discharge, and the light r emitted from the surface of the fluorescent paint 15 passes through the front glass substrate 11. And is emitted. In the drawing, reference numeral 18 denotes a low-pressure gas in a plasma state.

[0004]

The above-described plasma display panel has advantages that the viewing angle is wider than that of the liquid crystal display, which is advantageous in terms of increasing the screen size, and that the color reproducibility is good. On the other hand, improvement of image contrast and luminance have become important issues.

[0005] Since the contrast of a plasma display panel also depends on the ambient brightness, it is generally evaluated separately for dark room contrast and bright room contrast. In a conventional plasma display, the dark room contrast is
The ratio is about 50: 1 to 300: 1, and the bright room contrast is 40: 1 to 50: 1. Regarding the dark room contrast, it has reached a level that is almost unquestionable in practical use. The problem is a decrease in bright room contrast due to reflection of external light.

[0006] In order to solve the problem of the bright room contrast, a conventionally adopted method is to use an ND filter (Neutral Density Filte) on the front surface of a plasma display panel 10 like a plasma display device 1 shown in FIG.
r) 2 is arranged. External light passes through the ND filter 2 twice, once before and after being reflected by the plasma display panel 10, but light emitted from the plasma display panel 10 passes through the ND filter 2 only once. Therefore, assuming that the transmittance of the ND filter 2 is α (<1), the luminance of the light emitted from the plasma display panel 10 becomes α times and the external light becomes α ² times. Specifically, assuming that the transmittance of the ND filter 2 is, for example, α = １ ／, the light emitted from the plasma display panel 10 and the external light are α = １ ／ times the original, and α ² = 1/1, respectively. 4 times, and the contrast is 2: 1. Therefore, the brightness of the plasma display device is relatively improved, and the bright room contrast when external light is reflected is improved.

[0007]

However, in such a method, although the bright room contrast is improved,
Light emitted from the plasma display panel is once ND
Since the light passes through the filter, the amount of light is increased by α times (for example, 0.5 times).
Times). In this case, the brightness of the plasma display device, which is another problem, decreases,
This was not an ideal contrast improvement method.

The present invention has been made in view of the above-mentioned drawbacks of the conventional example, and has as its object to provide a plasma display device capable of improving the contrast without lowering the luminance of the screen. It is in.

[0009]

DISCLOSURE OF THE INVENTION (First Embodiment) A plasma display device according to a first aspect of the present invention includes a plasma display panel having a cavity in which a gas for emitting a phosphor by discharge is sealed, and a side of the plasma display panel. A light reflecting surface having an opening corresponding to each pixel of the plasma display panel, and a light reflecting surface having an opening corresponding to each pixel of the plasma display panel; And a light absorbing surface having an opening corresponding to each pixel of the plasma display panel.

[0010] In the plasma display device according to the first aspect, the incident external light can be absorbed by the light absorbing surface. Light generated in the cavity of the plasma display panel is emitted to the front from each opening of the light reflecting surface and the light absorbing surface while being repeatedly reflected on the light reflecting surface and the inside of the cavity. Therefore, the contrast at the time of external light reflection can be improved without lowering the light emission efficiency.

According to a second aspect of the present invention, in the plasma display device according to the first aspect, a lens array is provided on a front side of the light absorbing surface.

In this plasma display device, the light generated in the cavity is emitted through the openings of the light absorbing surface and the light reflecting surface, so that it has good coupling with the lens and can control the directivity of the light.

According to a third aspect of the present invention, there is provided a plasma display substrate, comprising: a glass substrate; a light reflecting surface having an opening corresponding to each pixel of the plasma display panel; and a light absorbing surface having an opening corresponding to each pixel of the plasma display panel. And a surface.

If this plasma display substrate is used as a glass substrate of a plasma display panel, the plasma display device of the present invention can be manufactured without changing the manufacturing process.

[0015]

FIG. 3 is a sectional view showing a plasma display device 3 according to an embodiment of the present invention. Since this is an improvement on the plasma display panel 10 shown in FIG. 1, the same components are denoted by the same reference numerals and description thereof will be omitted. In the plasma display device 3, the light control plate 4 is inserted between the dielectric layer 23 covering the cathode electrode 22 and the front glass substrate 11. In the light control plate 4, the surface on the cavity 17 side is a high reflectance surface 5 (for example, a total reflection layer) having a high light reflectance, and the opposite front surface is a light absorption surface 6. Further, as shown in FIG. 4, the light control plate 4 has a light transmission hole 7 at the center of each pixel of the plasma display panel 10. The shape of the light transmitting hole 7 is not particularly limited, such as a round hole and a square hole.

However, as shown in FIG. 5, external light incident on the surface glass substrate 11 of the plasma display device 3 is absorbed by the light absorbing surface 6 of the light control plate 4, and is hardly reflected to the front side. Specifically, assuming that the area of one pixel is S and the area of the light transmitting hole 7 is A, the external light incident on the plasma display device 3 is reflected only at a ratio of A / S at best, and By making 7 smaller, the ratio of external light reflected can be made very small.
On the other hand, the light r emitted by the fluorescent paint 15 in the cavity 17
Immediately passes through the light transmitting hole 7 of the light control plate 4 or passes through the light transmitting hole 7 of the light control plate 4 after being repeatedly reflected between the high reflectance surface 5 of the light control plate 4 and the inner surface of the cavity 17. Is emitted to the front of the plasma display panel 10,
Even if the light transmission hole 7 is made small, light can be efficiently emitted. Therefore, according to the plasma display device 3, the contrast when external light is incident can be improved without lowering the luminance of the pixel. In particular, this embodiment is preferable for a DC-type plasma display device in which pixels are separated in a grid pattern by partition walls 13.

FIG. 6 shows the relationship between the external light blocking ratio and the light output efficiency to the front surface when the ND filter is used, and the external light blocking ratio when the light control plate 4 of the present invention is used. The relationship with the light output efficiency to the front surface is shown. Here, the plasma display device 3 of the present invention used for the measurement is shown in FIG.
As shown in (b), the pixel pitch is Lp = 300 μm,
The thickness of the partition 13 is D = 50 μm, and the height of the partition 13 is H =
The light control plate 4 has a square light transmission hole 7, and the inner surface is a high reflectance surface 5 that totally reflects light and the outer surface is a light absorbing surface 6. The reflectivity in the cavity 17 is 0.9. Here, in the case of the plasma display device 3 of the present invention, if the area of the light transmitting hole 7 is A, and the area of the light absorbing surface 6 in one pixel is B (= SA), the light blocking ratio is B / S Was calculated. Referring to FIG. 6, when the transmittance of the ND filter is α = 0.5, the light shielding efficiency is 0.75, and the emission efficiency is 0.5. On the other hand, when the emission efficiency is also 0.5, in the plasma display device 3 of the present invention, the light blocking ratio is 0.87. Therefore, according to the present invention, it can be seen that the contrast can be increased without lowering the emission efficiency.

(Second Embodiment) FIG. 8 is a partially cutaway sectional view showing a plasma display device 31 according to another embodiment of the present invention. In this embodiment, a lens array 32 is provided on the front surface of the plasma display panel 10.
Is installed. In the lens array 32, each lens 33 is two-dimensionally arranged corresponding to a pixel. The individual lenses 33 provided in the lens array 32 are arranged so as to correspond to the respective pixels on a one-to-one basis. The center of the light transmission hole 7 of the light control plate 4 is
3 coincides with the optical axis.

In the plasma display device 31, since the light r emitted from each pixel is converted into a point light source by passing through the light transmission hole 7 of the light control plate 4, it is easily controlled by the lens 33. It is possible,
For example, the light r emitted from each pixel can be converted into collimated light after passing through the lens array 32.

(Third Embodiment) FIG. 9 is an exploded perspective view showing a plasma display device 34 according to still another embodiment of the present invention, partially broken away, and FIG. 10 is a rear view of a light control plate. This plasma display device is an AC-type plasma display device. The cavity 17 extends in one direction, and the partition wall 13 that partitions between the cavities 17 also extends in parallel with the cavity 17. In the case of such an AC type, the light control plate 4 having a light absorbing surface 6 on the front surface and a high reflectivity surface 5 on the back surface has a slit-like light transmission extending in a direction orthogonal to the cavity 17 and the partition 13. It is desirable to drill holes 7. The slit-shaped light transmitting holes 7 may be provided one by one for each pixel, or may be provided in plurals (FIG. 1).
0, two light transmission holes 7 are provided for one pixel). When a lens array is provided, the cavity 17
A rod lens array 35 in which rod lenses 36 extending in a direction parallel to the
It may be overlaid on the surface.

[Brief description of the drawings]

FIG. 1 is a sectional view showing a structure of a plasma display panel.

FIG. 2 is a schematic diagram showing a configuration of a conventional plasma display device in which contrast at the time of reflection of external light is improved using an ND filter.

FIG. 3 is a partially broken cross-sectional view illustrating a configuration of a plasma display device according to an embodiment of the present invention.

FIG. 4 is a partially broken plan view of a light control plate stacked above a cavity.

FIG. 5 is an operation explanatory view of the present invention.

FIG. 6 is a diagram showing the relationship between the light blocking ratio and the light emission efficiency of a conventional plasma display device including the plasma display device of the present invention and an ND filter.

7A and 7B are diagrams illustrating a sample of the present invention used in the measurement, in which FIG. 7A is a schematic cross-sectional view showing a structure for about one pixel, and FIG. FIG.

FIG. 8 is a partially broken sectional view showing a configuration of a plasma display device according to another embodiment of the present invention.

FIG. 9 is a partially broken perspective view showing a configuration of a plasma display device according to still another embodiment of the present invention.

FIG. 10 is a bottom view of the light control plate.

[Explanation of symbols]

 Reference Signs List 4 light control plate 5 high reflectivity surface 6 light absorption surface 7 light transmission hole 11 front glass substrate 12 back glass substrate 13 partition wall 15 fluorescent paint 17 cavity 32 lens array

Claims (3)

[Claims] 1. A plasma display panel having a cavity sealed with a gas for causing a phosphor to emit light by discharging, and a pixel disposed on the front side of the cavity toward the cavity, wherein each pixel of the plasma display panel is provided. A light-reflecting surface having an opening corresponding to, and a light-absorbing surface having an opening corresponding to each pixel of the plasma display panel, which is disposed on the front side of the surface having the reflection characteristics toward the side opposite to the cavity, Plasma display device provided with. 2. The plasma display device according to claim 1, wherein a lens array is provided on a front side of the light absorbing surface. 3. A plasma display substrate comprising a glass substrate, a light reflecting surface having an opening corresponding to each pixel of the plasma display panel, and a light absorbing surface having an opening corresponding to each pixel of the plasma display panel.