JPH10111511A - Reflection liquid crystal display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To efficiently use external light and to enhance luminance by providing a light transmission plate arranged on the side surface of a device and having the light receiving surface of the external light on its side surface, leading the external light incident on its light receiving surface through the light transmission plate and irradiating it from its one end onto the panel surface of the device. SOLUTION: This device consists of a device main body 1 and the light transmission plate 2 arranged on the side surface integrally with the device main body 1 so that the end part 5 of the light transmission plate 2 is placed on a display surface side of its one end. Although the external light 6 is made incident directly on the display surface of the device main body 1 also, the external light 6 incident on the light receiving surface 3 of the light transmission plate 2 enters from a groove or a notched part 4 the inside of the light transmission plate 2, and a part of it is led to the end part 5 of the light transmission plate 2 by total reflection to go out to the outside from the end part 5. By obliquely tilting the surface of the end part 5 as shown in the figure, the majority of the light emitted from the end part 5 to the outside is made incident on the display surface side of the device main body 1. Thus, the component incident from the light receiving surface 3 and emitted from the end part 5 through the light emission plate 2 is added to the display surface of the device main body 1 in addition to the directly incident external light component.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a reflection type liquid crystal display, and more particularly to a reflection type liquid crystal display which can be used even in a dark environment by efficiently using external light.

[0002]

2. Description of the Related Art A reflection type liquid crystal display device is a device which performs display by reflecting external light incident on a panel surface, and therefore does not require a backlight and consumes less power than a transmission type. There is an advantage.

However, on the other hand, the brightness of the reflection type liquid crystal display device depends on the amount of light incident on the panel surface, so that when the brightness of external light is dark, a low reflection brightness is necessarily obtained. was there.

[0004]

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems of the prior art, and has as its object to improve the brightness by efficiently using external light and to use the device even in a dark environment. To provide a possible reflective liquid crystal display.

[0005]

A reflection type liquid crystal display device according to the present invention which achieves the above object comprises a reflection type liquid crystal display device and a light guide arranged such that one end is located on one side of the display surface. The light guide is configured such that a light receiving unit that refracts and introduces external light within a predetermined solid angle into the light guide, a light guide that guides the introduced light to the one end, An irradiating unit for irradiating a display surface of the reflection type liquid crystal display device.

In this case, it is desirable that the light guide is formed of a transparent plate, and the light receiving portion is formed of a notch or a protrusion provided on one side surface of the plate. Further, it is desirable that one side surface of the plate-like body constitutes an irradiation part, and a lens is attached to the surface.

In the present invention, the light guide is provided on a part of the device such as the side surface of the reflection type liquid crystal display device or the back side of the spread cover, so that the size of the device can be reduced without increasing the size of the device. External light can be used efficiently by increasing the light component, and the display brightness is improved. Therefore, the reflective liquid crystal display device can be used even in a dark environment.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS According to the present invention, a light guide plate having a light receiving surface for external light on a side surface is provided side by side on a reflection type liquid crystal display device, and external light incident on the light receiving surface is guided through the light guide plate. By irradiating the light to the panel surface of the reflection type liquid crystal display device, the reflection luminance is remarkably improved. That is, by adding a light guide plate having a light receiving section, a light guide section, and an irradiation section to the conventional reflection type liquid crystal display device, external light is efficiently used to improve the luminance.

Hereinafter, specific embodiments of the reflection type liquid crystal display device of the present invention will be described with reference to the drawings. FIG.
As shown in a plan view (a) and a cross-sectional view (b) in FIG.
And a light guide plate 2 arranged in parallel with the reflective liquid crystal display device main body 1 so that the end 5 is located on the display surface side at one end. The reflection type liquid crystal display device main body 1 is, for example, a TFT.
The pixel electrodes on the TFT substrate also function as reflection / scattering plates. Light guide plate 2
Is a transparent plate made of acrylic resin or the like, and, in this embodiment, external light 6 within a predetermined solid angle is provided on the side surface 3 on the same side as the display surface of the reflective liquid crystal display device main body 1 by a light guide plate. 2, a plurality of saw-tooth-shaped grooves or notches 4 having a sawtooth cross-section so that the introduced light is guided by total reflection to the end portion 5 of the light guide plate 2 on the side of the reflection type liquid crystal display device main body 1. It is provided.

With such a configuration, the external light 6 directly enters the display surface of the reflection type liquid crystal display device 1, but the external light 6 incident on the light receiving surface 3 of the light guide plate 2 forms the groove or cut 4. From the light guide plate 2, a part of the light guide plate 2 is guided to the end 5 of the light guide plate 2 by total reflection, and exits from the end 5. End 5
1B is inclined obliquely as shown in FIG. 1B, so that most of the light emitted from the end portion 5 to the outside enters the display surface side of the reflective liquid crystal display device main body 1. . Therefore, the external light component directly incident on the display surface of the reflection type liquid crystal display device 1 is added with the component incident from the light receiving surface 3 and irradiated from the end portion 5 through the light guide plate 2, and the external light is efficiently used. And the display brightness is improved. Therefore, the reflective liquid crystal display device can be used even in a dark environment.

In the case of FIG. 1, the irradiation end 5 of the light guide plate 2 is an obliquely inclined flat surface, but as shown in FIG. In addition, the light condensing property of the light radiated from the end 5 to the outside is further enhanced, and most of the components incident from the light receiving surface 3 and irradiated from the end 5 through the light guide plate 2 are reflected by the reflection type liquid crystal display device 1. By making the light incident on the display surface, the utilization efficiency can be further improved.

Various configurations for introducing light into the light receiving surface 3 of the light guide plate 2 may be considered in addition to the saw-toothed grooves or cuts 4 shown in FIG. As one of such modifications, as shown in FIG. 3A, a prism body 41 having a triangular cross section with a smaller refractive index than the light guide plate 2 is attached to the light receiving surface 3 side of the transparent plate-like light guide plate 2. Alternatively, the external light 6 within a predetermined solid angle through one surface of the prism body 41 may be refracted and introduced into the light guide plate 2. FIG.
As shown in (a), a saw-toothed groove or notch 42 having a saw-tooth cross section is provided, and one surface thereof is used as a reflection surface 43.
The external light 6 within a predetermined solid angle reflected by 3 may be introduced into the light guide plate 2 through another refracting surface. Alternatively, the toothed grooves or cuts 4 and 42 having a sawtooth cross section as described above, or a prism body 41 having a triangular cross section may be provided on the surface opposite to the light receiving surface 3. Further, the light receiving surface 3 is entirely or partially or entirely or partially opposite to the light receiving surface 3 so as to be scattered so that the position becomes a secondary light source, and the light emitted secondarily there is scattered. The light may be guided in the light guide plate 2.

Instead of the light guide plate, light incident on the light receiving surface can be guided to a hologram or a lens by an optical fiber and irradiated on the entire display surface.

Next, one specific example of the reflection type liquid crystal display device of the present invention will be described. After forming an acrylic insulating layer by spin coating on the glass substrate on which the TFT is formed, roughening the surface of the acrylic layer, forming a contact hole with the TFT, and sputtering aluminum,
A reflection scattering electrode was formed by photolithography.

This substrate and a substrate on which an ITO film is formed on the entire surface of a pigment-dispersed color filter are bonded through a normal cell assembling process, and a phase-transition guest-host liquid crystal is injected to form a reflective color liquid crystal panel. Produced.

On the other hand, as the light guide plate, as shown in FIG. 1, an acrylic resin plate having a sawtooth-shaped groove in cross section and having the same surface shape as the reflective color liquid crystal panel was prepared. The angle made by the saw teeth refracts the light vertically incident on the light guide plate and allows it to enter.
The light guide plate was designed to be totally reflected and condensed toward the end. Next, a convex cylindrical lens was attached to the end where light condenses. The bonding angle between the end face of the end and the lens and the focal length of the lens are such that the light guide plate is parallel to the liquid crystal panel,
The design was made so that light from the lens illuminated the entire display surface when the lens side was positioned above the upper side of the liquid crystal panel.

The reflective type color liquid crystal panel and the light guide plate serving also as the light receiving portion, the light guide portion and the irradiation portion are connected by a hinge-shaped jig, and the angle is adjusted so as to show the above positional relationship. Was driven to measure the reflection luminance. As a result, the brightness was about 1.5 times that of a normal panel.

Although the reflection type liquid crystal display device of the present invention has been described based on several embodiments, the present invention is not limited to these embodiments, and various modifications are possible.

[0019]

As is apparent from the above description, according to the reflection type liquid crystal display device of the present invention, the light guide is provided on a part of the device such as the side surface of the reflection type liquid crystal display device or the back side of the spread cover. Thus, the external light component incident on the display surface can be increased and the external light can be used efficiently without increasing the size of the device, and the display brightness can be improved. Therefore, the reflective liquid crystal display device can be used even in a dark environment.

[Brief description of the drawings]

FIG. 1 is a plan view and a sectional view of an embodiment of a reflection type liquid crystal display device of the present invention.

FIG. 2 is a sectional view showing a modified example of an irradiation end of the light guide plate of FIG.

FIG. 3 is a cross-sectional view showing a modification of the configuration of the light receiving surface of the light guide plate of FIG.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Reflection type liquid crystal display device main body 2 ... Light guide plate 3 ... Light receiving surface 4 ... Groove or notch 5 ... Irradiation end 6 ... External light 7 ... Convex cylindrical lens 41 ... Triangular cross section prism 42 ... Groove or cut 43 ... Reflective surface

Claims (3)

[Claims] 1. A reflection type liquid crystal display device comprising: a reflection type liquid crystal display device; and a light guide arranged such that one end thereof is positioned on one side of the display surface, and the light guide transmits external light within a predetermined solid angle. A light receiving unit that refracts and introduces the light into the light guide, a light guiding unit that guides the introduced light to the one end, and an irradiation unit that irradiates the display surface of the reflective liquid crystal display device from the one end. Characteristic reflection type liquid crystal display device. 2. The light guide according to claim 1, wherein the light guide comprises a transparent plate, and the light receiving portion comprises a notch or a protrusion provided on one side surface of the plate. Reflective liquid crystal display. 3. The reflection type liquid crystal display device according to claim 2, wherein a surface of one side of the plate-like body constitutes the irradiation unit, and a lens is attached to the surface.