JPH0580332A - Liquid crystal display device - Google Patents

Abstract

PURPOSE:To provide the liquid crystal display device which attains a high contrast ratio by using a liquid crystal element which makes display by using scattering. CONSTITUTION:This liquid crystal display device consists of a polymer dispersion type liquid crystal panel 1, a display pattern 2, a light source 3, and a reflection plate 4. The light from the light source 3 is introduced by the reflection plate 4 to the polymer dispersion type liquid crystal panel 1. Then, the display pattern 2 is observed when the polymer dispersion type liquid crystal panel 1 is in a transparent state. On the other hand, the light from the light source 3 is scattered in the polymer dispersion type liquid crystal panel 1 and, therefore, the bright display is obtd. and the display pattern 2 is not observed when the polymer dispersion type liquid crystal 1 is in a scattering state. The liquid crystal display device having the high contrast ratio is obtd. by using this means.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid crystal display device, and more particularly, to a structure suitable for realizing a high contrast ratio in a liquid crystal display device using scattering.

[0002]

2. Description of the Related Art As a liquid crystal display device using scattering, for example, there is one in which a display pattern is attached to the back surface of a polymer dispersion type liquid crystal panel. When no voltage is applied to the polymer-dispersed liquid crystal, the panel becomes cloudy and the display pattern on the back surface is not observed. On the other hand, when a voltage is applied, it becomes a transmissive state, and the display pattern on the back surface is observed. However, in reality, the scattering property of the polymer dispersed liquid crystal is insufficient, so that the pattern on the back surface is observed even when no voltage is applied.

As a method for realizing a high contrast ratio in a liquid crystal display device using scattering, for example, Japanese Patent Application Laid-Open No. 59-59
The technology described in Japanese Laid-Open Patent Publication No. 178428 is known. This conventional technology uses a louvered light control film,
The incident light is directed outside the viewing angle on the observation side, and a bright display is displayed when scattered and a dark display is displayed when transmitted.

[0004]

The above-mentioned prior art is realized by directing the direction of light to the outside of the viewing angle when displaying black. However, this method has a problem that the viewing angle becomes narrow. is doing.

An object of the present invention is to solve the above-mentioned problems of the prior art and to realize a high contrast ratio in a wide viewing angle in a liquid crystal display device using scattering.

[0006]

According to the present invention, the above object is achieved by injecting light from an end face of a liquid crystal panel having scattering.

[0007]

The present invention comprises a liquid crystal panel having scattering, a light source for entering light from the end surface of the panel, and a display pattern provided on the back surface of the panel. When the display panel is in the scattering state, the light incident from the panel end surface is scattered in the display panel, resulting in a very bright display, and the pattern on the back surface is not observed. On the other hand, when the display panel is in the transmissive state, the pattern on the back surface is observed.

[0008]

1 is a sectional view showing the structure of a first embodiment of the present invention. Polymer dispersed liquid crystal panel 1, display pattern such as printed matter provided on the back surface of the polymer dispersed liquid crystal display panel 2, light source provided at the end of the polymer dispersed liquid crystal panel 3, light from the light source is guided to the polymer dispersed liquid crystal panel It consists of a reflector 4. FIG. 2 is a view of the configuration of the embodiment of the present invention viewed from above. The reference numerals in the figure are the same as those in FIG. FIG. 3 is a sectional view showing the structure of the polymer dispersion type liquid crystal panel 1. It is composed of a pair of glass substrates 5, a transparent electrode 6, and a polymer dispersed liquid crystal 7. When a voltage is applied to the polymer dispersed liquid crystal 7, the polymer dispersed liquid crystal 7 becomes transparent and the display pattern 2
Is observed. On the other hand, when no voltage is applied to the polymer dispersion type liquid crystal 7, the light emitted from the light source 3 is scattered in the polymer dispersion type liquid crystal panel 1 to be displayed in white,
Display pattern 2 is not observed. When the light source 3 is not provided, the display pattern 2 on the back side can be seen through because the scattering by the polymer dispersed liquid crystal 7 is small. However, when this configuration is used, the display pattern 2 on the back side is not observed because the polymer dispersed liquid crystal 7 seems to shine by the light from the light source 3 at the time of scattering.

In the above embodiment, a display device having a small parallax can be realized by using a member having a display pattern instead of the lower glass substrate 5.

In the above embodiment, the polymer dispersed liquid crystal panel is a panel in which pixels are arranged in a matrix and the display pattern is a black absorbing plate.
A black and white liquid crystal display device capable of displaying an arbitrary pattern can be realized. Also in this case, a display device with a small parallax can be realized by using a black absorbing plate instead of the lower glass substrate. Also, the same effect can be obtained by using an electrode having absorption instead of the lower electrode.

[0011]

As described above, according to the present invention,
By providing a pattern such as printed matter on the back side of the polymer dispersion type liquid crystal panel and a light source at the end, a pattern is displayed when the polymer dispersion type liquid crystal is in a transparent state, and a white display is displayed when the polymer dispersion type liquid crystal is in a scattering state. Display device can be realized.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing a configuration of an exemplary embodiment of the present invention.

FIG. 2 is a diagram of the configuration of the embodiment of the present invention viewed from above.

FIG. 3 is a cross-sectional view showing a configuration of a polymer dispersion type liquid crystal panel.

[Explanation of Codes] 1 ... Polymer dispersion type panel, 2 ... Display pattern, 3 ... Light source, 4 ... Reflector, 5 ... Glass substrate, 6 ... Transparent electrode, 7 ...
Polymer dispersed liquid crystal.

Claims (5)

[Claims] 1. A liquid crystal panel comprising a pair of transparent substrates and a liquid crystal layer which is disposed between the pair of substrates and which is in an optically transparent or scattering state in response to a voltage applied between the substrates. A liquid crystal display device comprising means for allowing light to enter from an end portion of the liquid crystal panel. 2. The liquid crystal display device according to claim 1, wherein a printed matter is provided on one of the liquid crystal layers. 3. The liquid crystal display device according to claim 1, wherein one of the liquid crystal layers has a member that absorbs light. 4. The liquid crystal display device according to claim 3, wherein the light absorbing member is one of electrodes for applying a voltage to the liquid crystal layer. 5. The liquid crystal display device according to claim 1, wherein the liquid crystal layer is a liquid crystal layer in which liquid crystal is dispersed in a polymer.