JP3180498B2 - Liquid crystal rear projector device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rear projection type liquid crystal rear projector, and more particularly, to a rear projection type liquid crystal rear projector using a combination of a plurality of liquid crystal projectors.

[0002]

2. Description of the Related Art FIG. 3 illustrates a general concept of a liquid crystal projector. According to this, the liquid crystal projector P includes a light source 1, a liquid crystal panel 2, a projection lens 3, and a condenser lens 4 for condensing light from the light source 1 to the projection lens 3.

The light source 1 is generally a parabolic reflector 1
a and is located at its focal point. Thereby, the light source 1
From the liquid crystal panel 2. A video signal is supplied to the liquid crystal panel 2 via a liquid crystal driver circuit (not shown), and a predetermined video is displayed on the liquid crystal panel 2.

Therefore, when the light from the light source 1 passes through the liquid crystal panel 2, the image is enlarged and projected on the screen 5 via the projection lens 3. The light source 1
The condenser lenses 4 are arranged with their optical axes aligned so as to illuminate the liquid crystal panel 2 in a well-balanced manner.

FIG. 4 is a side view of a rear projection type liquid crystal rear projector device in which a reflection mirror 6 and a transmission type screen 5 are combined with the above liquid crystal projector P.

[0006]

Although this liquid crystal rear projector apparatus has been evaluated in that the apparatus itself can be reduced in size, it has a problem that the luminance tends to be insufficient. This problem of insufficient luminance becomes more pronounced as the screen becomes larger. In addition, as a problem of the liquid crystal panel, there is a problem of insufficient resolution due to a shortage of the number of pixels.

On the other hand, in order to enlarge the screen, as shown in FIG. 5, conventionally, for example, two independent liquid crystal rear projectors P1 and P2 are combined. The decrease in the brightness of the seam is a problem. Note that this decrease in luminance is caused by the illuminance distribution of the illumination system and the peripheral light amount ratio of the projection lens.

[0008]

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned conventional circumstances, and its structural features include a light source having a reflector, a liquid crystal panel on which a predetermined image is displayed, and light from the light source. A liquid crystal projector including a projection lens for enlarging and projecting an image on the liquid crystal panel, a transmission screen, and a reflection mirror for reflecting an image projected from the liquid crystal projector toward the transmission screen. In a liquid crystal rear projector device, when a plurality of the liquid crystal projectors are provided, one image is divided into the number of images, displayed on the liquid crystal panel of each liquid crystal projector, and reproduced as one image on the transmission screen. The object of the present invention is to make the effective image range of each projection lens half that of the same lens, and arrange each liquid crystal panel in the effective image range.

In this case, by covering the light reflecting surface of the reflector with a spherical mirror in half, the effective image range of each projection lens can be reduced to half that of the lens.

[0010]

According to the above arrangement, one image is divided and displayed on the liquid crystal panel of each projector, and reproduced on the screen as one original image. Here, if the screens have the same size, when a plurality of projectors are used, the brightness and the number of pixels are twice the number of projectors used.

In addition, since the display size per projector is small, the projection distance can be shortened.
The depth dimension of the device is reduced.

Further, by covering the light reflecting surface of the reflector by half with a spherical mirror and making the effective image area of each projection lens half of that of the lens, the light use efficiency is enhanced and a brighter image as a whole is obtained. Can be

[0013]

Embodiments of the present invention will be described below.
FIG. 1 shows an example in which a rear projection type liquid crystal rear projector device is formed by using two liquid crystal projectors P1 and P2. Each of the liquid crystal projectors P has basically the same configuration as the liquid crystal projector P of FIG. 3 described above, and therefore, the same reference numerals are used for the reference numerals.

According to this embodiment, the liquid crystal projector P
To each of the liquid crystal panels 2 and 1 of P2, a video signal obtained by dividing one video into two is supplied via a liquid crystal driver circuit (not shown). As a result, a half-divided image is displayed on each of the liquid crystal panels 2 and 2, and the divided image is transmitted from each of the liquid crystal projectors P1 and P2 to the reflection mirrors 6 and 6.
The image is projected onto a transmission type screen 5a via the display 6 and reproduced as one original image.

It can be seen from this figure that if the screen size is the same, the depth dimension is further shortened. The screen 5a is a lenticular lens + Fresnel lens, and the Fresnel lens is preferably a single Fresnel lens having two optical axes.

FIG. 2 is a conceptual diagram of the optical system of the liquid crystal rear projector device shown in FIG. 1. In the present invention, the effective image range of each of the projection lenses 3 and 3 of each of the liquid crystal projectors P1 and P2 is changed. The liquid crystal panels 2, 2 are arranged in the effective image area.

According to this embodiment, since the effective image area of the projection lens 3 is set to half of that of the lens, the front surface of the reflector 1a composed of the corresponding parabolic mirror, that is, almost half of the light emitting surface is formed by a spherical mirror. Cover 1b.

[0018] Therefore, according to this, since a decrease in the brightness of the joint is small and the light use efficiency is high, a brighter image can be obtained as a whole.

[0019]

As described above, according to the present invention, a liquid crystal rear projector device is provided with a plurality of liquid crystal projectors, and one image is divided into the number of images and displayed on the liquid crystal panel of each liquid crystal projector. By reproducing the image as a single image on the transmission screen, a high-definition and high-luminance image can be reproduced. In addition, it is possible to display a high-quality image with a small decrease in luminance at the joint.

[Brief description of the drawings]

FIG. 1 is a schematic diagram showing one embodiment of a liquid crystal rear projector device according to the present invention.

FIG. 2 is a conceptual diagram showing an optical system of the embodiment.

FIG. 3 is a schematic diagram schematically showing a general configuration of a liquid crystal projector.

FIG. 4 is a side view showing a conventional liquid crystal rear projector device.

FIG. 5 is a conceptual diagram showing an optical system when two conventional liquid crystal rear projectors are combined.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Light source 1a Reflector 1b Spherical mirror cover 2 Liquid crystal panel 3 Projection lens 4 Condenser lens 5a Screen 6 Reflection mirror P Liquid crystal projector

Claims (2)

(57) [Claims] A liquid crystal projector including a light source having a reflector, a liquid crystal panel on which a predetermined image is displayed, and a projection lens for enlarging and projecting the image on the liquid crystal panel with light from the light source; A liquid crystal rear projector device comprising: a reflection mirror that reflects an image projected from the liquid crystal projector toward the same transmission type screen; a plurality of the liquid crystal projectors; When the image is displayed on the liquid crystal panel of each liquid crystal projector and reproduced as one image on the transmissive screen, the effective image area of each projection lens is set to half of the same lens, and each liquid crystal panel is arranged in the effective image area. A liquid crystal rear projector device characterized in that: 2. An effective image area of each of said projection lenses is made half of said lens by covering substantially half of a light reflecting surface of said reflector with a spherical mirror.
3. The liquid crystal rear projector device according to item 1.