JP2000075270A - Liquid crystal display - Google Patents

Abstract

(57) [Summary] [PROBLEMS] To provide a liquid crystal display which has little dependence on external light, has high visibility, and can display many different colors. SOLUTION: When light from a light source 11 is incident on a light guide 8, a light guide plate 6 disposed between a polymer dispersed liquid crystal layer 5 and a reflection plate 7 emits light. High visibility is obtained irrespective of. The light incident on the light guide 8 may be white light or monochromatic light, and the color of the reflector 7 may be white or color. Since 5 may include a dye, many different color displays are possible. Further, the color of the light incident on the light guide 8 from the light source 11 changes with time, or the voltage is applied to the transparent electrodes 1 and 3 arranged so as to sandwich both surfaces of the polymer-dispersed liquid crystal layer 5 and the light is guided. Many different colors can be displayed even when light is incident on the body 8.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to a liquid crystal display.

[0002]

2. Description of the Related Art In a direct-view display device using a polymer-dispersed liquid crystal (hereinafter referred to as "PDLC"), in order to make use of its brightness and wide viewing angle, light is reflected on one surface of a transparent substrate sandwiching the PDLC. A simple structure with plates is used.

[0003]

However, the conventional structure in which a reflector is simply arranged on one surface of a transparent substrate sandwiching PDLC has the following problems.

(A) Visibility is extremely low where external light is weak, and it is completely invisible where there is no external light.

(B) To make the display multi-color, P
There is a method in which a pigment is mixed into the liquid crystal constituting the DLC, a color reflector is used as the reflector, or a pigment and a color reflector are used at the same time. In each case, general external light (natural light or fluorescent light) is used. Light from a light or white light bulb)
In the case of relying only on dark colors, dark colors such as purple and blue are inferior in visibility, so that only colors with high visibility such as yellow and green are used, and the number of usable colors is limited.

Accordingly, an object of the present invention is to solve the above-mentioned problems and to provide a liquid crystal display which has little dependence on external light, has high visibility, and can display many different colors. .

[0007]

In order to achieve the above object, a liquid crystal display of the present invention comprises a polymer dispersed liquid crystal layer, and a light transmitted through the polymer dispersed liquid crystal layer. In a direct-view type liquid crystal display having a reflecting plate,
A light guide plate for emitting light incident on the side surface from another surface is disposed between the polymer-dispersed liquid crystal layer and the reflection plate, and the rod-shaped light guide for emitting light incident on the end surface from the side surface is the light guide plate. It is arranged on the side of.

In the liquid crystal display of the present invention, the light incident on the light guide from the light source may be white light or monochromatic light.

In addition to the above configuration, the liquid crystal display of the present invention may be arranged such that the color of the light incident on the light guide from the light source changes with time.

In the liquid crystal display of the present invention, in addition to the above configuration, the reflector may be a white reflector or a color reflector.

In the liquid crystal display of the present invention, in addition to the above constitution, the polymer-dispersed liquid crystal layer may contain a dye.

In addition to the above structure, the liquid crystal display of the present invention is characterized by interlocking the application of a voltage to a transparent electrode arranged so as to sandwich both surfaces of a polymer dispersed liquid crystal layer and the incidence of light on a light guide. Is also good.

According to the present invention, when light from a light source enters the light guide, the light guide plate disposed between the polymer-dispersed liquid crystal layer and the reflector emits light. High visibility is obtained irrespective of. Further, the light incident on the light guide may be white light or monochromatic light, the color of the reflector may be white or color, and the polymer dispersed liquid crystal layer may be a dye. May be included, so that many different colors can be displayed. Further, the color of the light incident on the light guide from the light source changes with time, the voltage is applied to the transparent electrode disposed so as to sandwich both sides of the polymer dispersed liquid crystal layer, and the light is incident on the light guide. Can be displayed in many different colors.

[0014]

Embodiments of the present invention will be described below in detail with reference to the accompanying drawings.

FIG. 1 is an external perspective view showing an embodiment of the liquid crystal display of the present invention, and FIG. 2 is a sectional view taken along line AA of FIG.

As shown in FIG. 2, one surface (the lower surface in the figure)
A transparent substrate 2 having a transparent electrode 1 and a transparent substrate 4 having a transparent electrode 3 on one surface (the upper surface in the figure) have a pigment-free polymer-dispersed liquid crystal so that the transparent electrodes 1 and 3 face each other. The layer (hereinafter, referred to as “PDLC layer”) 5 is held in a sandwiched state. A light guide plate 6 made of transparent plastic is provided on the other surface (the lower surface in the figure) of the transparent substrate 4. The light guide plate 6 converts the light incident on the side surface 6a into another surface 6a.
b, 6c, and 6d (the plane perpendicular to the paper is omitted).

A green reflector 7 is provided outside the light guide plate 6. The reflection plate 7 has a function of reflecting light transmitted through the PDLC layer 5 to the PDLC layer 5.

A rod-shaped (or prismatic) light guide 8 made of transparent plastic is arranged on a side surface of the light guide plate 6. The light guide 8 has a function of emitting light incident on the end face 8a from the side face 8b.

The transparent electrodes 1, 3 and the transparent substrates 2, 4,
A liquid crystal display 9 is composed of the PDLC layer 5, the light guide plate 6, the reflection plate 7, and the light guide 8.

One end (the upper end in the figure) of the optical fiber 10 is connected to one end (the right end in the figure) of the light guide 8 of the liquid crystal display 9 shown in FIG. At the lower end), a light source (for example, a tungsten lamp) 11 is arranged.

When the external light (white light) has a sufficient intensity, when no voltage is applied between the transparent electrodes 1 and 3, the liquid crystal display 9 scatters the external light and causes the liquid crystal display 9 to move to the transparent substrate 2. When viewed from the side, it looks white, but when a voltage is applied between the transparent electrodes 1 and 3, the PDLC layer 5 becomes colorless and transparent, and thus looks green, which is the color of the reflector 7.

When the external light is weak and becomes difficult to see as it is, white light from the light source 11 is incident on the light guide plate 6 through the optical fiber 10 and the light guide 8 so that the light guide plate 6 emits light. The liquid crystal display 9 looks bright and clear green when viewed from the transparent substrate 2 side.

Next, the wavelength range of light incident on the light guide plate 6 is
By disposing the filter at the position indicated by the broken line 12 and changing the wavelength from the short wavelength side to the long wavelength side, the color viewed from the transparent substrate 2 side is not only green, but also blue green, green, yellow green,
Can be changed to yellow. Alternatively, the color of light incident on the light guide 8 may be gradually changed while a voltage is applied between the transparent electrodes 1 and 3. Further, the presence / absence of voltage application between the transparent electrodes 1 and 3 is interlocked with the change in the wavelength region of the light incident on the light guide 8 to discontinuously change the color viewed from the transparent substrate 2 side. Can be.

Although a green reflector is used as the reflector 7 in this embodiment, the present invention is not limited to this, and the reflector 7 may have any color. Further, when a voltage is applied between the transparent electrodes 1 and 3 to generate a character or graphic pattern, the color of the reflector 7 may be changed every time the pattern is displayed. Further, the light source 11 is not limited to a tungsten lamp, and may use a single LED or a plurality of LEDs having different emission wavelengths to emit a mixed color. The light may be transmitted through a filter or a spectroscope to emit light in a specific wavelength region. Further, the light guide plate 6 is not limited to a transparent plastic and may be a glass plate, and the light guide 8 may be a glass rod.

In the above, according to the present invention, the PDLC
In a liquid crystal display device using a light guide plate, a light guide plate is arranged between the PDLC layer and the reflector, and a light guide for making light incident on the light guide plate is arranged on a side surface of the light guide plate. In addition, by injecting light in various wavelength regions, it is possible to realize the provision of a direct-view type liquid crystal display which has little dependence on external light, has high visibility, and can display many different colors. .

[0026]

In summary, according to the present invention, the following excellent effects are exhibited.

The dependence on external light is small, the visibility is high,
In addition, it is possible to provide a liquid crystal display capable of displaying many different colors.

[Brief description of the drawings]

FIG. 1 is an external perspective view showing one embodiment of a liquid crystal display of the present invention.

FIG. 2 is a sectional view taken along line AA of FIG.

[Explanation of symbols]

 1, 3 transparent electrode 2, 4 transparent substrate 5 polymer dispersed liquid crystal layer (PDLC layer) 6 light guide plate 7 reflector 8 light guide 9 liquid crystal display

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 2H038 AA52 BA42 2H089 HA04 QA16 TA20 2H091 FA23Z FA41Z FB02 FD06 FD21 LA16 5G435 AA01 AA04 BB12 BB15 BB16 CC12 EE27 EE33 FF03 FF08 GG18 GG23 HH02

Claims (6)

[Claims] 1. A direct-view liquid crystal display comprising a polymer-dispersed liquid crystal layer and a reflector for reflecting light transmitted through the polymer-dispersed liquid crystal layer to the polymer-dispersed liquid crystal layer. A light guide plate for emitting light incident on the other surface from the other surface is disposed between the polymer dispersed liquid crystal layer and the reflector, and a rod-shaped light guide for emitting light incident on an end surface from the side surface is provided on the light guide plate. A liquid crystal display, wherein the liquid crystal display is disposed on a side surface of a light plate. 2. The liquid crystal display according to claim 1, wherein the light incident on the light guide from the light source is white light or monochromatic light. 3. The liquid crystal display according to claim 2, wherein the color of the light incident on the light guide from the light source changes with time. 4. The liquid crystal display according to claim 3, wherein said reflector is a white reflector or a color reflector. 5. The liquid crystal display according to claim 4, wherein the polymer dispersed liquid crystal layer contains a dye. 6. The liquid crystal display according to claim 5, wherein voltage application to a transparent electrode disposed so as to sandwich both sides of the polymer dispersed liquid crystal layer and light incidence on the light guide are linked. body.