JPH0511233A - Polymer dispersion type liquid crystal display device - Google Patents

Abstract

PURPOSE:To make a colored display of a selective range by selectively feeding electricity to electrodes without mixing dichroic dye with liquid crystal. CONSTITUTION:A ultraviolet-ray lamp is arranged on the top surface side of a polymer dispersed type liquid crystal display element 1 and a back light source part (EL lamp) 4 for visible light is arranged on the back surface across a louver part 3; while the louver part 3 cuts off the back light (state (d)), the ultraviolet rays (a) are transmitted through an electric field applied part (liquid crystal array part) and absorbed by the liquid crystal at an electric field unapplied part (liquid crystal nonarray), so that the liquid crystal colors in royal purple. Further, when the back light is projected to the top surface side at the louver part 3, the back light is transmitted straightly at the liquid crystal array part (electric field applied part). Therefore, when the back light is cut off, a selective color display of royal purple (b) and black (dark color) is made, but when the back light is transmitted, a selective color display of royal purple (b) and white (light color) is made.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a display device using a polymer dispersion type liquid crystal display device in which liquid crystals are microcapsules (small spheres) in a polymer matrix and dispersed and held.

[0002]

2. Description of the Related Art In a polymer dispersion type liquid crystal display device in which liquid crystal is dispersed and held in a polymer matrix, the scattering and transmission of light incident on the liquid crystal display device can be controlled by an electric field effect, and the liquid crystal is sealed between substrates. Since it is easy to increase the area as compared with a liquid crystal cell type display element, its application range is wide not only for displays but also for light control such as lighting adjustment of windows, and it is currently attracting attention. .

The liquid crystal used in the above-mentioned liquid crystal display device is mainly a nematic liquid crystal (in addition to this, a liquid crystal such as a cholestic liquid crystal or a smectic liquid crystal is also possible), which has a structure in which this liquid crystal is dispersed and held in a polymer matrix. The specific structure thereof is determined by the materials of the matrix and the liquid crystal, the conditions for forming the element, etc., and various kinds are known at present. For example, as shown in Japanese Patent Publication No. 58-501631, etc., polyvinyl alcohol (PVA), which is a polymer having a hydroxyl group, is used as a matrix, and a nematic liquid crystal (Δε> 0) is emulsified with water as a dispersion medium. It is known that a liquid crystal is microencapsulated and held in PVA by forming an emulsion. Further, Japanese Patent Laid-Open No. 60-252687 discloses a means of using latex as a matrix and emulsifying the liquid crystal with the latex in water to form an emulsion, and as a result, obtaining latex-incorporated liquid crystal. Further, Japanese Patent Publication No. 61-502128 discloses a means for dispersing and retaining liquid crystal microdroplets by a phase separation method using an epoxy resin as a matrix.

A display device using this liquid crystal display element is often used in which a dichroic dye is mixed in a liquid crystal capsule, and the dichroic dye tends to be aligned in the same direction as the liquid crystal molecules. Therefore, when no electric field is applied, the light incident on the liquid crystal capsule is scattered and absorbed by the dye to darken the transmitted light, and when the electric field is applied, the liquid crystal molecules are aligned,
The principle of brightening transmitted light (however, it is slightly colored due to the dye pigment) is used (Actually, Shokai 60-252687).
issue).

[0005]

When color display is to be performed using a liquid crystal display device in which liquid crystal capsules are dispersed and held in the polymer matrix described above, a large amount of dye is added to the liquid crystal capsules to make the liquid crystal transparent when an electric field is applied. It is conceivable to increase the coloring of the transmitted light, or to strengthen the light of the backlight and display the color by the scattered transmitted light.
However, the former is limited by the manufacturing method depending on the type of dye (polymerization phase separation is difficult), which causes new problems such as driving voltage, voltage increase, current increase, and dye deterioration, while the latter causes display light to scatter. Since it is light, the display lacks clarity, and the transmitted light at the time of transparency becomes too strong, making it unsuitable for display.

Therefore, in the color display of the liquid crystal display element, a colored fluorescent paint is applied to the back surface of the liquid crystal display element in accordance with the display pattern. However, the colored display was set within a predetermined range, and selective colored display could not be performed by cutting off the current to the electrodes. Therefore, the present invention enables colored display within a selective range by selectively energizing the counter electrode of the liquid crystal display element.

[0007]

A polymer-dispersed liquid crystal display device according to the present invention is a liquid crystal display device having a liquid crystal sheet in which a liquid crystal material is microencapsulated and dispersed and held in a polymer matrix between counter electrode substrates. A surface light source unit that irradiates the liquid crystal display device with ultraviolet rays from the front side, a louver unit provided with an inclined light shielding plate arranged on the back face of the liquid crystal display device, and a back light source unit arranged on the back face of the louver unit,
And a tilting mechanism for tilting at least the louver portion.

More particularly, in the above-mentioned display device, an EL lamp is adopted in the back light source part, and a liquid crystal display element and a tilting mechanism for integrally tilting the louver part and the back light source part are provided. To do.

[0009]

When the liquid crystal display element is irradiated with ultraviolet light, the liquid crystal develops bluish violet when the liquid crystal absorbs the ultraviolet light as shown in FIG. Further, in the portion to which the electric field is applied in the liquid crystal display device, the liquid crystals in the capsules are aligned and the ultraviolet rays pass through without being absorbed by the liquid crystals.

Light from the back light source of visible light arranged on the back surface of the liquid crystal display element is blocked by the louver portion when energized, but enters the liquid crystal display element when tilted to the louver portion. At this time, the incident light on the part to which the electric field is applied in the liquid crystal display element is transmitted to the surface side of the liquid crystal display element because the liquid crystal is aligned, and becomes scattered light by the liquid crystal capsule in the part to which the electric field is not applied.

Therefore, when the visible light from the rear light source is blocked by the louver portion, the electric field applying portion of the liquid crystal display element emits a dark color (black) and the non-electric field applying portion emits a bluish purple light, and a predetermined amount is emitted. When the display is made and the louver portion is tilted, the dark portion is displayed brightly (the color is determined by the hue from the light source).

[0012]

EXAMPLES Next, examples of the present invention will be described. The liquid crystal display device according to the present invention comprises a liquid crystal display element 1, a surface light source section 2, a louver section 3, a back light source section 4 and a housing case 5 for these, and the liquid crystal display element 1 is a well-known polymer dispersion type liquid crystal. That is, a liquid crystal sheet 12 in which a liquid crystal material is microencapsulated and dispersed and held in a polymer matrix is interposed between electrode substrates 11a and 11b each having a transparent electrode formed on a transparent substrate. Surface light source unit 2
Is an ultraviolet lamp, the rear light source unit 3 is a white light emitting EL lamp, and the louver unit 3 is a sheet-like unit having a micro-sized blind-like inclined louver unit. The liquid crystal element 1, the front light source section 2, the louver section 3, and the rear light source section 4 are housed in the housing case 5, but the liquid crystal display element 1, the louver section 3, and the rear light source section 4 are the louver section 3. An appropriate tilting mechanism (not shown) attached to the case body 5 by arranging them in the middle and stacking them into a single sheet to be integrated.
It is stored in the case body 5 so that it can be tilted. The surface light source unit 2 is arranged on the surface side of the liquid crystal display element 1 in the case body 1 so as to irradiate the liquid crystal display element 1 with ultraviolet rays, and an ultraviolet ray filter 51 is arranged on the surface (display window) of the case body 5. I will do it.

However, when the louver portion 3 blocks the emission of white light from the rear light source portion 4 to the front surface side (the state of FIG. 2A), the display light source is only the front light source portion 2, and the surface light source When the ultraviolet light a of the portion 2 irradiates the liquid crystal display element 1, the display light varies depending on whether or not the electrodes of the liquid crystal display element 1 are energized, that is, the alignment and misalignment of the liquid crystal due to the application or non-application of the electric field. Specifically, in the liquid crystal alignment (voltage application) portion, the ultraviolet ray a is directly transmitted and absorbed by the louver portion 3, or even when reflected, it is absorbed by the ultraviolet filter 51.
Further, in the portion where the liquid crystal is not aligned (electric field is not applied), the ultraviolet light a is absorbed by the liquid crystal, and the liquid crystal exhibits a bluish purple color b.

Therefore, in the case of only displaying the surface light source unit 2,
A predetermined display is made by selectively energizing the electrodes, and the display is made of a black portion and a blue-violet colored portion. When the tilting mechanism is operated and the light from the rear light source unit 4 is emitted to the front side (state of FIG. 2B), the liquid crystal alignment portion (electric field application portion) has a white light source color c (bright color). Since the light is emitted, the display is made of a blue-violet portion and a white portion.

In the above-mentioned embodiment, since the rear light source section 4 is an EL lamp and the liquid crystal display element 1 and the louver section 3 are formed into a sheet shape, the tilting of the louver section 3 effectively blocks and passes light. However, the present invention is not limited to the above-mentioned embodiment, and at least only the louver portion may be tilted, and the back light source portion is not limited to the EL lamp, and the visible light can be used. Any illumination mechanism may be adopted if it exists.

[0016]

As described above, the present invention uses the polymer dispersion type liquid crystal display device, irradiates ultraviolet rays from the front surface side, and emits visible light from the rear surface to the front surface side through the louver portion. Two-color display of bluish purple and black (dark color) is performed by blocking the light of the louver, and two-color display of bluish purple and white (light color) is performed by transmitting the light of the louver, and is especially encapsulated. It enables color display without mixing dye in the liquid crystal.

[Brief description of drawings]

FIG. 1 is an exploded perspective view showing an embodiment of the present invention.

2A and 2B show the action of light, in which (A) shows a non-inclined state and (B) shows an inclined state.

FIG. 3 is a sectional view of the entire device of the present invention.

FIG. 4 is a graph showing an ultraviolet characteristic of liquid crystal.

[Explanation of symbols]

1 Liquid crystal display element 2 Surface light source (ultraviolet lamp) 3 Louver part 4 Rear light source (EL lamp) 5 Case part 51 UV Filter

Claims (2)

[Claims] 1. A liquid crystal display device having a liquid crystal sheet in which a liquid crystal material is microencapsulated and dispersed and held in a polymer matrix between opposed electrode substrates, and a surface light source for irradiating the liquid crystal display device with ultraviolet rays from the surface side. Section, a louver section provided with an inclined shading plate arranged on the back surface of the liquid crystal display element, a back light source section arranged on the back surface of the louver section, and a tilting mechanism for tilting at least the louver section. Polymer dispersion type liquid crystal display device. 2. The polymer dispersion type liquid crystal display device according to claim 1, wherein an EL lamp is adopted as a back light source part, and a liquid crystal display element, a louver part and a back light source part are laminated and integrated to form a whole. A polymer-dispersed liquid crystal display device comprising a tilting mechanism for tilting operation.