JPH05165026A - Liquid crystal display device - Google Patents

Abstract

PURPOSE:To enable a single liquid crystal display panel to display a color image without use of any color filter or dichroic mirror. CONSTITUTION:On the back of a liquid crystal display panel, a photo reflex body 2 is installed which reflects white light from light sources 4A, 4B, 4C to the panel 1, and a plurality of diffractive lattice grooves 3 are formed at the concavely curved reflecting surface 2a of the photo-reflex body 2, wherein the light sources 4A, 4B, 4C are put on and off under control in the predetermined sequence and, at the same time, the driving of the panel 1 is controlled in synchronization with putting-on/off of the light sources.

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 for displaying a color image.

[0002]

2. Description of the Related Art Conventionally, in this type of liquid crystal display device, for example, a color filter is arranged on the back surface of a liquid crystal display panel, and illumination light (white light) from a light source is colored by the color filter into three primary colors of red, blue and green. Then, the color image is displayed. However, in such a liquid crystal display device, since the color filter may be decolorized by ultraviolet rays from the light source, it is vulnerable to heat, and moreover, one pixel is formed by three pixels. There was also a problem that the resolution became coarse. Therefore, recently, instead of using a color filter, a liquid crystal display device using a spectroscopic means such as a dichroic mirror has been developed.

[0003]

However, in such a liquid crystal display device, the illumination light from the light source is split into three primary color lights of red, blue, and green by a plurality of dichroic mirrors, and the split red, It is necessary to make three primary color lights of blue and green incident on three liquid crystal display panels corresponding to red, blue and green, and combine the red, blue and green image lights transmitted through these liquid crystal display panels into one image light. Therefore, there is a problem that the entire device becomes large and the cost becomes high.

The present invention has been made in view of the above points, and an object thereof is a liquid crystal display capable of displaying a color image on a single liquid crystal display panel without using a color filter or a dichroic mirror. It is intended to provide a device.

[0005]

In order to solve the above-mentioned problems, the present invention is directed to a light reflector having a reflecting surface curved in a concave shape, and a liquid crystal arranged with its back surface facing the reflecting surface of the light reflector. A display panel, first to third light sources for irradiating the reflection surface of the light reflector with white light at a predetermined incident angle, and a plurality of diffraction grating grooves formed on the reflection surface of the light reflector. And a control means for controlling lighting of the light sources in a predetermined order and driving control of the liquid crystal display panel in synchronization with the lighting operation of the light sources.

[0006]

According to the structure of the present invention, when the first to third light sources are sequentially turned on, the lights of the three primary colors of blue, green and red sequentially enter the liquid crystal display panel. By driving the liquid crystal display panel in synchronization with, it becomes possible to display a color image on one liquid crystal display panel without using a color filter, a dichroic mirror, or the like.

[0007]

FIG. 1 shows a schematic structure of a liquid crystal display device according to an embodiment of the present invention. In FIG. 1, reference numeral 1 denotes a liquid crystal display panel, and a light reflector 2 is arranged on the back side of the liquid crystal display panel 1 with a reflecting surface 2 a facing the liquid crystal display panel 1.

The light reflector 2 includes light sources 4A, 4B and 4C.
The illumination light (white light) from is reflected toward the liquid crystal display panel 1, and the concave reflecting spherical surface 2a of the light reflector 2 has a large number of diffractions as shown in FIG. The lattice grooves 3 are formed in parallel with each other at equal intervals. These diffractive grating grooves 3 are for forming a diffractive grating on the reflecting surface 2a of the light reflector 2, and each of the illuminations applied to the reflecting surface 2a of the light reflector 2 from the light sources 4A, 4B, 4C. The light is made to enter the liquid crystal display panel 1 by the diffraction grating groove 3 into three primary color lights of blue, green and red.

Here, assuming that the radius of the Rowland circle 5 which is the focus curve of the diffraction grating formed on the reflection surface 2a of the reflector 2 in the light source 4A is 100 cm, the reflection surface 2a which is the focus of the diffraction grating is assumed. It is arranged on the Roland circle 5 which is about 1.4 cm away from the center of curvature O. Further, the light source 4B is arranged on the Rowland circle 5 which is about 1.7 cm away from the center of curvature O of the reflecting surface 2a, and the light source 4C is arranged on the Rowland circle 5 which is about 2.3 cm away from the center of curvature O of the reflecting surface 2a. Has been done.

When the light sources 4A, 4B and 4C are arranged at predetermined positions on the Rowland circle 5 as described above, the reflecting surface 2
When the pitch of the grooves 3 formed in a is 0.5 μm, the diffraction angles of the illumination light emitted from the light sources 4A, 4B, and 4C to the reflecting surface 2a are 2.6 °, 3.0 °, and 4 °, respectively. Since it becomes 0.2 °, it is possible to make the three primary color lights of blue, green and red enter the liquid crystal display panel 1 depending on the difference in the incident angle.

Blue incident on the liquid crystal display panel 1,
The lights of the three primary colors of green and red are transmitted through the liquid crystal display panel 1 and are incident on the projection lens 6 arranged at the converging point of the light reflector 2 (center of curvature of the reflection surface 2a), and the screen 7 is passed through this projection lens 6. It is projected on.

The light sources 4A, 4B and 4C are light source drive signals LS1 and LS from the timing control circuit 9 shown in FIG.
2 and LS3 are lit in a predetermined order. This timing control circuit 9 is based on the horizontal and vertical sync signals from the sync separation circuit 8 and is the light source 4A,
4B and 4C are turned on in a predetermined order, and blue, green, and red images are displayed on the liquid crystal display panel 1 as light sources 4A, 4B, and
The display is displayed in synchronization with the lighting operation of 4C. The timing control circuit 9 outputs the light source drive signal LS described above.
1, LS2, LS3, a segment driver drive signal SS that drives the segment driver 22 of the liquid crystal display panel 1, a common driver drive signal CS that drives the common driver 23 of the liquid crystal display panel 1, and the chroma circuit 1
0 to blue, green, and red image signals B, G, and R are used as light sources 4A, 4
A timing control signal TS that is output in synchronization with the lighting operation of B and 4C is output.

The chroma circuit 10 outputs blue, green, and red image signals B, G, and R as image data for one screen, respectively, and the image signal output from the chroma circuit 10 is output. B, G, and R are input to the segment driver 22 of the liquid crystal display panel 1 via the A / D converter 11. The liquid crystal display panel 1 includes a panel body 21, a segment driver 22 that drives the segment electrodes of the panel body 21, and a panel body 2.
The common driver 23 drives one common electrode.

In the liquid crystal display device configured as described above, when the light sources 4A, 4B and 4C are sequentially turned on as shown in FIG. 4, the three primary color lights of blue, green and red are sequentially displayed on the liquid crystal display panel 1. It will be incident. Therefore, the light sources 4A, 4
In synchronization with the lighting operation of B and 4C, blue on the liquid crystal display panel 1,
By displaying images corresponding to green and red, a color image can be displayed on one liquid crystal display panel without using a color filter or a dichroic mirror.

The present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the gist of the present invention. For example, the first to third light sources 4A, 4B, and 4C have a single light source at the first position and the second light source at the second position.
The position may be sequentially moved to the third position.

[0016]

As described above, the present invention provides a light reflector having a reflecting surface curved in a concave shape, a liquid crystal display panel arranged with its back surface facing the reflecting surface of the light reflector, and First to third light sources that irradiate the reflecting surface of the reflector with white light at a predetermined incident angle, a plurality of diffraction grating grooves formed on the reflecting surface of the light reflector, and the light source are predetermined. The liquid crystal display panel is provided with means for displaying the red, blue and green images in synchronism with the lighting operation of the light source. Therefore, the first
When the third light source is sequentially turned on, the lights of the three primary colors of blue, green and red are sequentially incident on the liquid crystal display panel. Therefore, by driving the liquid crystal display panel in synchronization with the lighting operation of the light source. It is possible to provide a liquid crystal display device capable of displaying a color image on a single liquid crystal display panel without using a color filter or a dichroic mirror.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram of a liquid crystal display device according to an embodiment of the present invention.

FIG. 2 is a detailed view of a portion A shown in FIG.

FIG. 3 is a control block diagram of the liquid crystal display device according to the embodiment.

FIG. 4 is an operation explanatory view of the liquid crystal display device shown in FIG.

[Explanation of symbols]

1 ... Liquid crystal display panel, 2 ... Light reflector, 2a ... Reflective surface, 3
... Diffraction grating grooves, 4A, 4B, 4C ... Light source, 6 ... Projection lens, 8 ... Sync separation circuit, 9 ... Timing control circuit, 10
... chroma circuit, 11 ... A / D converter, 21 ... panel body, 22 ... segment driver, 23 ... common driver.

Claims (1)

[Claims] 1. A light reflector having a concavely curved reflecting surface, a liquid crystal display panel arranged with its back surface facing the reflecting surface of the light reflecting body, and a predetermined reflecting surface of the light reflecting body. First to third light sources that emit illumination light at an incident angle, a plurality of diffraction grating grooves formed on the reflecting surface of the light reflector, and the light sources are controlled to light in a predetermined order and A liquid crystal display device, comprising: a control unit that controls driving of the liquid crystal display panel in synchronization with a lighting operation of the light source.