JPH06347743A - Liquid crystal projection type display device - Google Patents

Abstract

PURPOSE:To provide a liquid crystal projection type display device which is miniaturized, whose number of parts is reduced and whose cost is made low. CONSTITUTION:In this liquid crystal projection type display device (liquid crystal projector), 3 a light beam generated from a light source lamp 201 is separated into the components of three primary colors being green, blue and red, by dichroic mirrors for separation 211 and 212, and the respective components are allowed to pass through optical shutters (light valves) 231, 232 and 233 for changing the transmissivity of the liquid crystal based on the luminance information of a video signal, and further they are synthesized by the dichroic mirrors 2)42 and 243 for synthesizing and formed into a color image on a screen via a projection lens 244. The liquid crystal light valves 231, 232 and 233 are arranged on the same surface, and, desirably, they are integrally constituted through a substrate 234.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid crystal projection type display device called a liquid crystal projector or the like, and more particularly to a dichroic mirror for separating three colors and a liquid crystal light valve for controlling light transmittance. The present invention relates to a liquid crystal projection display device which forms a color image on a screen through a single projection lens by using a liquid crystal element called as.

[0002]

2. Description of the Related Art A conventional liquid crystal projection display device of this type is
Generally, the configuration is shown in FIG. In FIG. 1, 10
1 is a light source lamp, 102 is a reflector, 103 is UV, IR
It is a filter. Reference numerals 111 and 112 are separation dichroic mirrors having a pass band and a stop band according to the spectrum of light rays, 113 and 141 are total reflection mirrors, and 142 and 143 are combining dichroic mirrors for combining images of respective colors. Reference numerals 121, 122 and 123 denote condenser lenses for condensing light, and 131, 132 and 13
3 is R (red), G (green), B of three primary color components respectively
It is a liquid crystal light valve for (blue). 144 is a projection lens.

A light beam emitted from a light source lamp (usually using a metal halide lamp) 101 is converted into a parallel light beam by a reflecting plate 102, and a dichroic mirror 11 for separation is used.
By 1, the G component and the B component are reflected, and the R component is transmitted. The UV / IR filter 103 has a function of absorbing ultraviolet rays harmful to the human body. Further, the optical path is shown by a broken line.

The R component light beam is bent at a right angle by a total reflection mirror 141, and a condenser lens (condensing lens) 1
The light is focused by the projection lens 144 by 21 to be focused. A liquid crystal light valve (optical shutter) 131, which expresses brightness and darkness, by modulating the transmittance of the R component light according to the R video signal level, at a position very close to the condenser lens 121.
Are placed.

On the other hand, the G component and the B component reflected by the separating dichroic mirror 111 are reflected by the separating dichroic mirror 112 and the B component is transmitted. The G component and B component light rays separated in this way are condensed by the condenser lenses 122 and 123, respectively, as in the R component described above, and the liquid crystal light valves 132 and 133 convert the respective component light components into their respective video signal levels. The brightness is expressed by modulating the transmittance with. The G component light beam modulated by the liquid crystal light valve 132 is reflected by the synthesizing dichroic mirror 141 to the above R
Combined with component rays. This combining dichroic mirror is basically the same as the separating dichroic mirror, and controls transmission / reflection of light with a certain light spectrum as a boundary.

The light beam of the B component modulated by the liquid crystal light valve 133 is bent at a right angle by the total reflection mirror 113, and all the R, G, B components are combined by the combining dichroic mirror 143 and the projection lens. An image is formed on a screen (not shown) by 144, and a function as a display for displaying a full-color moving image or a still image is exhibited.

[0007]

As described above, since the optical system is conventionally designed easily (for example, only one type of imaging lens is required), as shown in FIG. In addition, a configuration system has been adopted in which the distance from the liquid crystal light valves 131, 132, 133 to the projection lens 144 is kept constant. However, at this time, the liquid crystal light valve 13
1, 132 and 133 are not on the same plane as is apparent from FIG.

This greatly hinders downsizing and cost reduction of the device. That is, the three sets of liquid crystal light valves 131, 132, 133 which are divided by all means
Is required.

Also, three liquid crystal light valves 131, 1
One or more of 32 and 133 are arranged horizontally to the ground. This suggests the possibility of image quality deterioration due to the adhesion of dust, and can be a fatal defect of the display device. Note that this can be solved by disposing the liquid crystal light valve and the projection lens (for example, not disposing the three liquid crystal light valves horizontally with the ground).
The physical shape of the optical device, and hence the entire device, is significantly restricted, which may be impractical.

The present invention has been made in order to solve the above-mentioned conventional drawbacks, and the purpose thereof is to arrange a plurality of liquid crystal light valves on the same plane and to treat them as one unit, and An object of the present invention is to provide a liquid crystal projection display device that can be downsized, the number of parts can be reduced, the cost can be reduced, and the dustproof property can be improved.

[0011]

In order to achieve the above object, the present invention uses a light beam generated from a light source to generate green, blue and red light.
A plurality of separation dichroic mirrors that are separated into primary color components, and the transmittance of the liquid crystal is changed according to the luminance information of the video signal for each of the three primary color components of green, blue, and red separated by each of the separation dichroic mirrors. A plurality of liquid crystal light valves, a plurality of combining dichroic mirrors that combine the light beams of the three primary color components that have passed through the liquid crystal light valves, and the light beams combined by the combining dichroic mirrors are imaged on the screen. The liquid crystal light valve is arranged on the same plane.

[0012]

In the present invention, since a plurality of liquid crystal light valves are arranged on the same plane, the device can be made smaller, especially thin, and the liquid crystal light valve mounting structure and mounting adjustment can be simplified. Further, by treating the liquid crystal light valves on the same surface as one body and treating them as one liquid crystal panel, it is possible to reduce the number of parts and hence the cost. For example, a high-definition direct-viewing type liquid crystal display panel can be applied to a projection type display, the range of use for one liquid crystal is expanded, and the cost can be reduced. Further, since it is not necessary to dispose the liquid crystal light valve on the horizontal plane, it is preferable from the viewpoint of dustproof, and the range of selection of the optical device shape is widened.

[0013]

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

FIG. 2 shows a schematic structure of a liquid crystal projection display device according to an embodiment of the present invention. In FIG. 2, 201 is a light source lamp, 202 is a reflector, and 203 is a UV / IR filter. Reference numerals 211 and 212 are separation dichroic mirrors, 213 and 241 are total reflection mirrors, and 242 and 243 are combining dichroic mirrors. 221,
222 and 223 are condenser lenses, and
1, 232 and 233 are liquid crystal light valves for R, G and B, respectively, and 244 is a projection lens.

In this embodiment, each liquid crystal light valve 23
1, 232, and 233 are arranged on the same surface on the same substrate 234, and the surfaces are arranged substantially perpendicular to the ground.
The substrate 234 is a mounting substrate and is a transparent plate or a frame having a plurality of mounting windows. Further, the liquid crystal light valves 231, 232, 233 may be of a type in which one liquid crystal panel is divided into screens for use.

These liquid crystal light valves 231, 232,
Condenser lenses 221 and 223 respectively
One of the light source side mirror groups 211, 212 and 213 and the projection lens side mirror groups 241 and 242, which are attached to the light source side, are arranged side by side in the same direction. , 243.

Incidentally, each condenser lens 221, 22
The focal lengths of 2 and 223 are determined corresponding to the difference in optical distance between the corresponding liquid crystal light valve and the projection lens 144, for example.

Now, the configuration of this embodiment shown in FIG. 2 and the above-mentioned FIG.
Comparing the configuration of the conventional example of No. 1, the liquid crystal light valve (231, 131) of R component and its condenser lens (22
1, 121), and a B component liquid crystal light valve (233, 133) and its condenser lens (223).
The other positions are the same except for the arrangement position for each total reflection mirror and the posture of the arrangement of the group 123). Therefore, in the explanation of the operation of the present embodiment, if the numeral in the hundreds of each constituent element in FIG.
Except for the points, it is the same as the conventional example.

The order of the condenser lens 221, the liquid crystal light valve 231, and the total reflection mirror 241 is reversed.

Similar to, but with the set of condenser lens 223 and liquid crystal light valve 233 and total reflection mirror 2
The order of 13 is reversed.

In other words, the most characteristic feature is that the functionally identical display can be constructed by changing the arrangement of the liquid crystal light valves without changing the components other than the liquid crystal light valve. .

[0022]

As described above, according to the present invention, the following effects can be obtained.

(1) Since three liquid crystal light valves can be formed on the same substrate, a wide variety of displays can be realized with one type of liquid crystal panel, and the size of the device can be reduced and the number of parts can be reduced. Cost reduction can be expected.

(2) Since the liquid crystal light valve does not have to be formed on the horizontal plane, the design margin of the optical device provided with the dustproof measure increases. In other words, the fact that the liquid crystal surface does not have to be arranged on a horizontal plane means that the dust affects the transmittance and reflectance of light rays and the chances of causing image quality deterioration are drastically reduced.

[Brief description of drawings]

FIG. 1 is a layout configuration diagram showing a schematic internal configuration of a conventional liquid crystal projection display device.

FIG. 2 is a layout configuration diagram showing a schematic internal configuration of a liquid crystal projection display device according to an embodiment of the present invention.

[Explanation of symbols]

101, 201 Light source lamp 102, 202 Reflector plate 103, 203 UV, IR filter 111, 112, 211, 212 Separation dichroic mirror 113, 141, 213, 241 Total reflection mirror 121, 122, 123, 221, 222, 223 Condenser Lens 131,132,133,231,232,233 Liquid crystal light valve 142,143,242,243 Synthetic dichroic mirror 144,244 Projection lens 234 Substrate

Claims (1)

[Claims] 1. Light rays emitted from a light source are classified into green, blue, and red rays.
A plurality of separation dichroic mirrors that are separated into primary color components, and the green separated by each of the separation dichroic mirrors,
A plurality of liquid crystal light valves that change the transmittance of the liquid crystal according to the luminance information of the video signal for each of the three primary color components of blue and red, and the respective light rays of the three primary color components that have passed through the respective liquid crystal light valves are synthesized. It has a plurality of dichroic mirrors for composition and a lens system for forming an image of the light beam combined by the dichroic mirrors for composition on a screen, and the liquid crystal light valves are arranged on the same plane. Liquid crystal projection display device.