JPH10228062A - Liquid crystal projector - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enlarge and project a bright color image having good quality at low cost by arranging a branching means for branching white illuminating luminous flux into three ones, a liquid crystal panel with a microlens array, and a color absorption filter for three primary colors RGB which projects spectroscopic output of three primary colors to a projection lens in order. SOLUTION: A light source 11, the branching means 12, the liquid crystal panel with a microlens array 13, the color absorption filter 14 and the projection lens 15 are arranged in order. By such constitution, a condenser lens emitting the white luminous flux excellent in parallelism is disused, so that cost is reduced. Furthermore, by making the area of the filter 14 functioning as a spectroscopic means three times as large as the area of the panel 13, the light resistance and the heat resistance of the filter 14 less expensive than a dichroic mirror are improved. Therefore, transmitted light quantity is increased while maintaining specified spectroscopic characteristics, and a bright color video is enlarged and projected to a screen 16.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid crystal projector for enlarging and projecting an image on a liquid crystal panel surface irradiated with illumination light from a light source onto a screen by a projection lens.

[0002]

2. Description of the Related Art As a prior art related to the present invention, there is a color liquid crystal display device disclosed in Japanese Patent Application Laid-Open No. Hei 4-60538. FIG. In FIG. 4, the color liquid crystal display device 50 includes:
White light source 51, spherical mirror 52, condenser lens 53, dichroic mirror 54 (R, G, B), micro lens array 55, liquid crystal display element 56, field lens 5
7, a projection lens 58 and a screen 59.

[0003] The spherical mirror 52 is disposed on the back of the white light source 51 in order to reflect white light emitted from the white light source 51 and increase the light use efficiency. Condenser lens 53
Converts the white light emitted from the white light source 51 into a parallel white light flux, and converts the parallel white light flux into a dichroic mirror 54 (R, G,
B).

[0004] Three types of dichroic mirrors 54 (R,
G, B) are arranged at different angles from each other by several degrees with respect to the incident optical axis, and R (red), G (green), and B (blue) from the parallel white light flux from the condenser lens 53, respectively. The light beams are selectively reflected at different angles from each other, and the reflected R, G, and B color light beams are emitted to the microlens array 55 in mutually different directions.

The microlens array 55 is provided integrally with the liquid crystal display element 56, and emits three kinds of R, G, and B color light beams incident from dichroic mirrors 54 (R, G, B) from mutually different directions. Are condensed on the pixel openings of the different liquid crystal display elements 56 respectively.

The liquid crystal display element 56 modulates the transmittance of each pixel opening based on an external color image signal (not shown), and projects a color light beam passing through each pixel opening via a field lens 57 through a projection lens 58. Out.

The projection lens 58 enlarges and projects the color image formed by the liquid crystal display element 56 on a screen 59.

As described above, the color liquid crystal display device 50
The light source includes three dichroic mirrors that selectively reflect the three primary colors of R, G, and B, and a liquid crystal display element that modulates a plurality of color light beams incident from different directions to form a color image. It says that light can be used without waste, so that it is possible to reduce the size and to enlarge and project a brighter color image on a screen.

[0009]

However, in the color liquid crystal display device disclosed in Japanese Patent Application Laid-Open No. Hei 4-60538, three dichroic mirrors are used as spectral means, and are slightly different from each other with respect to the optical axis. There is a problem that the cost increases because it is necessary to install the device at a predetermined angle with high accuracy.

Further, in the color liquid crystal display device disclosed in Japanese Patent Application Laid-Open No. Hei 4-60538, the hue is greatly affected by the parallelism of the white light entering the dichroic mirror from the condenser lens. There is a need for a condenser lens that converts the generated white light into a white light flux with good parallelism and emits the light to the dichroic mirror, which causes a problem of high cost.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems of the prior art, and an object of the present invention is to provide white illumination light from a light source between a light source and a liquid crystal panel with a microlens array in three optical paths. Branching means for irradiating a liquid crystal panel with a microlens array with white illumination light branched in three directions different from each other, and RG is provided on the emission side of the liquid crystal panel
It is an object of the present invention to provide a liquid crystal projector in which a B-spectral unit is arranged and which is inexpensive, has good image quality, and can enlarge and project a bright color image.

[0012]

In order to achieve the above object, a liquid crystal projector according to the present invention splits a parallel white illumination light beam from a light source into three light paths between a light source and a projection lens. The white illumination luminous flux branched into
A branching means for emitting light from a direction to a common liquid crystal panel with a microlens array, a liquid crystal panel having a group of pixel openings corresponding to three primary color pixels of a color image enlarged and projected on a screen, and a liquid crystal panel attached to the liquid crystal panel And a liquid crystal panel with a microlens array comprising a microlens array for emitting mutually different three directions of white illumination light beams from the branching means to different pixel opening groups of the liquid crystal panel, and a liquid crystal panel with a microlens array. A three-primary-color RGB color-absorbing filter for emitting a three-primary-color spectral output obtained by transmitting mutually different three-primary-color RGB luminous fluxes from three mutually different white luminous fluxes that have passed through the pixel opening to a projection lens; , Are arranged in order.

In the liquid crystal projector according to the present invention, a parallel white illumination light beam from the light source is branched into three light paths between the light source and the projection lens, and the white illumination light beams branched into the three light paths are divided from three different directions. A branching means for emitting light to a common liquid crystal panel with a microlens array, a liquid crystal panel having a group of pixel openings corresponding to three primary color pixel groups of a color image enlarged and projected on a screen, and provided on the liquid crystal panel A liquid crystal panel with a micro lens array comprising a micro lens array for emitting mutually different three directions of white illumination light beams from the branching means to different pixel opening groups of the liquid crystal panel, and each pixel opening of the liquid crystal panel with the micro lens array Of the three primary colors obtained by transmitting the RGB light beams of three different primary colors from the white light beams of three different directions passing through the unit. And a color absorption filter of three primary colors RGB for emitting the output to the projection lens are arranged in order, so that a condenser lens for emitting a white light beam with good parallelism is not required, and the area of the color absorption filter is provided with a micro lens array. The area of the liquid crystal panel can be tripled, and the light resistance and heat resistance of the color absorption filter can be improved as spectral means.

Further, a liquid crystal projector according to the present invention comprises:
Between the light source and the projection lens, parallel white illumination light from the light source is branched into three optical paths, and the white illumination light branched into the three optical paths is emitted from three different directions to a common liquid crystal panel with a microlens array. A branching means, a liquid crystal panel having a group of pixel openings corresponding to the three primary color pixel groups of the color image enlarged and projected on the screen, and a mutually different white color from the branching means provided in the liquid crystal panel from the branching means A liquid crystal panel with a microlens array comprising a microlens array that emits an illuminating light beam to a different group of pixel openings of the liquid crystal panel, and each of three different directions passing through each pixel opening of the liquid crystal panel with a microlens array Are arranged substantially perpendicular to the white light flux of the three primary colors RG
It is characterized in that three dichroic mirrors for sequentially outputting a spectral output obtained by transmitting the B light beam to a projection lens are arranged in order.

In the liquid crystal projector according to the present invention, three parallel white illumination lights from the light source are interposed between the light source and the projection lens.
A branching unit for branching the white illumination light into the optical path and emitting the white illumination light to the common liquid crystal panel with a microlens array from three different directions, and a three primary color pixel group of a color image enlarged and projected on a screen. A liquid crystal panel having a corresponding group of pixel openings; and a microlens array attached to the liquid crystal panel and emitting mutually different three-direction white illumination light beams from the branching unit to different groups of pixel openings of the liquid crystal panel. And a liquid crystal panel with a microlens array, and RGB light beams of three primary colors that are arranged substantially perpendicularly to white light beams in three different directions passing through respective pixel openings of the liquid crystal panel with a microlens array. The spectral output obtained by transmitting the light beam is emitted to the projection lens 3
Since the two dichroic mirrors are arranged in order, a condenser lens that emits a white light beam with good parallelism is not required, and the installation accuracy of the three dichroic mirrors as spectral means is high as in the conventional example. Accuracy is not required, and a bright white illumination light can be applied to the liquid crystal panel with the microlens array up to the limit of light resistance of the liquid crystal panel with the microlens array by using a high-output light source.

[0016]

Embodiments of the present invention will be described below with reference to the accompanying drawings. FIG. 1 is an explanatory diagram of a first embodiment of a liquid crystal projector according to the present invention. In FIG. 1, a liquid crystal projector 1 includes a light source 11 and a branching unit 12.
, A liquid crystal panel 13 with a microlens array, a color filter 14, and a projection lens 15 in this order.

The branching means 12 is constituted by a reflecting mirror, a reflecting prism, or the like, and divides the parallel white illumination light beam 11-1 emitted from the light source 11 into three optical paths, and splits the parallel white illumination light beam into three optical paths. The light beams (12-1, 12-2, 12-3) are emitted to the common liquid crystal panel with microlens array 13 from three different directions.

Liquid crystal panel 13 with micro lens array
Is composed of a micro lens array 13M and a liquid crystal panel 13L as shown in FIG.
3M is provided on the branching unit 12 side at a ratio of one to three pixel openings of the liquid crystal panel 13L.

The microlens array 13M enlarges and projects the white illumination light beams (12-1, 12-2, 12-3) incident on the microlens array 13M from the branching means 12 from three directions according to the incident directions. The light is emitted to the pixel openings of the liquid crystal panel 13L corresponding to the three primary color RGB pixel groups of the color image to be reproduced.

A group of pixel openings (R (1)) of the liquid crystal panel 13L
... R (n)) correspond to the primary color R pixel group of the color image enlarged and projected on the screen, and the pixel opening groups (G (1) to G (n)) of the liquid crystal panel 13L correspond to the color image on the screen. , And the pixel aperture groups (B (1) to B (n)) of the liquid crystal panel 13L correspond to the primary color B pixel groups of the color image on the screen.

According to FIG. 2, the micro lens array 13
M (i) indicates that the micro lens array 13
The white illumination light 12-1 (i) incident on M (i) is
The white illumination light 12-2 (i) is applied to the pixel opening G (i) of the liquid crystal panel 13L in the pixel opening R (i) of L, and the white illumination light 12-3 (i) is applied to the pixel opening G (i) of the liquid crystal panel 13L.
Is emitted to the pixel opening B (i) of the liquid crystal panel 13L.

3 instead of the microlens array 13M
Using a light-shielding plate (similar to a shadow mask of a cathode ray tube) or the like in which a hole is formed in each pixel, a white illumination light beam (12-1, 12-2, 12-3) incident from three directions is incident. May be emitted to the pixel opening group of the liquid crystal panel 13L corresponding to the three primary color RGB pixel groups of the color image enlarged and projected on the screen in accordance with the above.

The liquid crystal panel 13L receives a group of pixel openings (R (1), G (G)) based on a color video signal input to the liquid crystal panel 13L.
(1), B (1),..., R (n), G (n), B (n)) modulating the transmittance to form a white light flux (13-1, 13-2, 13)
-3) is emitted to the color absorption filter 14.

The liquid crystal panel 13L includes a white light flux 13 transmitted through a group of pixel openings (R (1) to R (n)) of the liquid crystal panel 13L.
-1, the white light flux 13-2 transmitted through the pixel aperture group (G (1) to G (n)), and the white light flux 13 transmitted through the pixel aperture group (B (1) to B (n)) And -3 are emitted in mutually different directions so as to be spatially separated at the position of the color absorption filter 14.

The color absorption filter 14 is formed by arranging R, G, and B transmission filters one by one in parallel. The white light flux 13-1 transmitted through the pixel aperture group (R (1) to R (n)) of the liquid crystal panel 13 with the microlens array enters the R transmission filter of the color absorption filter 14, and the G transmission filter receives the white light flux 13-1. White luminous flux 1 transmitted through a group of pixel openings (G (1) to G (n))
The white light flux 13-3 transmitted through the pixel aperture group (B (1) to B (n)) is incident on the B transmission filter.

The R transmission filter of the color absorption filter 14 is
The spectral output 14 -R, which has transmitted the primary color R image from the incident white light flux 13-1, is emitted to the projection lens 15. Similarly, the G transmission filter of the color absorption filter 14 receives the incident white light flux 1.
The spectral output 14-G transmitted through the primary color G image from 3-2, and the spectral output 14-B transmitted through the primary color B image from the incident white light flux 13-3 are emitted to the projection lens 15 from the B transmission filter.

The projection lens 15 is arranged so that the pixel opening on the liquid crystal panel 13 with the microlens array and the screen 16 are in an image forming relationship with each other, and the three spectral outputs (14) from the color absorption filter 14 are provided. -R, 14-G, 1
4-B) is enlarged and projected on the screen 16 to synthesize a color image.

As described above, the liquid crystal projector 1 is provided with the light source 11, the branching means 12, the liquid crystal panel 13 with the micro lens array, and the projection lens 15 arranged in this order.
A condenser lens that emits a white light beam with good parallelism is not required, the area of the color absorption filter can be three times the area of the liquid crystal panel with a microlens array, and the light resistance of a color absorption filter that is less expensive than a dichroic mirror as a spectral unit. Properties and heat resistance can be improved, and the amount of transmitted light can be increased while maintaining predetermined spectral characteristics.

FIG. 3 is an explanatory diagram of a second embodiment of the liquid crystal projector according to the present invention. In FIG. 3, the liquid crystal projector 3 includes a branching unit 22 and a liquid crystal panel with a micro lens array 23 between a light source 21 and a projection lens 25.
And dichroic mirrors (24R, 24G, 24B)
Are arranged in order.

In the liquid crystal projector 3, dichroic mirrors (24R, 24G, 24B) having better light resistance than the color absorption filter 14 are arranged in place of the color absorption filter 14 which is the spectral means of the liquid crystal projector 1 shown in FIG. Thus, it is possible to enlarge and project a brighter color image on the screen. The operations of the light source 21, the spectral unit 22, the liquid crystal panel with microlens array 23, and the projection lens 25 of the liquid crystal projector 3 are the same as those of the light source 11, the spectral unit 12, the liquid crystal panel with microlens array 13, and the projection lens of the liquid crystal projector 1. Fifteen
Since these are the same as those described above, their description will be omitted.

The dichroic mirror 24R is connected to a group of pixel openings (FIG. 2:
R (1) to R (n)) are arranged perpendicularly to the emission direction of the white light beam 23-1 that has transmitted therethrough, and project a spectral output 24-R that transmits only the primary color R light from the white light beam 23-1. Emitted to 25.

Similarly, the dichroic mirror 24G is arranged perpendicularly to the emission direction of the white light beam 23-2 transmitted through the pixel aperture group (FIG. 2: G (1) to G (n)).
The dichroic mirror 24B transmits the spectral output 24-G that has transmitted only the primary color G light from 3-2 to the pixel aperture group (FIG. 2: B
(1) to B (n)) are arranged perpendicular to the emission direction of the white light beam 23-3, and the projection lens 25 receives the spectral output 24-B that transmits only the primary color B light from the white light beam 23-3. Out.

The projection lens 25 is arranged so that the pixel opening on the liquid crystal panel 23 with the microlens array and the screen 26 are in an image-forming relationship with each other, and is projected from the dichroic mirror 24 (R, G, B). The three spectral outputs (24-R, 24-G, 24-B) are enlarged and projected on the screen 26 to synthesize a color image.

As described above, the liquid crystal projector 3 includes the light source 21, the branching means 22, the liquid crystal panel 23 with the micro lens array, and the dichroic mirror 24 having excellent light resistance.
(R, G, B) and the projection lens 25 are arranged in this order, so that a condenser lens for emitting a white light beam with good parallelism is not required, and the installation accuracy of the three dichroic mirrors as spectral means is improved. A high-precision unlike the conventional example is not required, and a bright white illumination light can be applied to the microlens array-equipped liquid crystal panel up to the limit of light resistance of the microlens array-equipped liquid crystal panel using a high-output light source.

The present invention is not limited to the above embodiment.

[0036]

According to the present invention, the following effects are exhibited by the above configuration. In the liquid crystal projector according to the present invention, a parallel white illumination light beam from the light source is branched into three light paths between the light source and the projection lens, and the white illumination light beams branched into the three light paths are shared from three different directions by a common micro-beam. A branching unit for emitting light to a liquid crystal panel with a lens array, a liquid crystal panel having a group of pixel openings corresponding to three primary color pixels of a color image enlarged and projected on a screen; The liquid crystal panel with a microlens array, which comprises a microlens array that emits white illumination light beams in three different directions to different pixel opening groups of the liquid crystal panel, and passes through each pixel opening of the liquid crystal panel with a microlens array The spectral outputs of the three primary colors obtained by transmitting the mutually different RGB light beams of the three primary colors from the white light beams of the three different directions are projected to the projection lens. And a color absorption filter of the three primary colors R, G, and B, which are sequentially arranged, and a condenser lens that emits a white light beam with good parallelism is not required. By increasing the filter area to three times the area of the liquid crystal panel with a microlens array, it is possible to improve the light resistance and heat resistance of a color absorption filter that is less expensive than a dichroic mirror, so that the amount of transmitted light can be increased while maintaining a predetermined spectral characteristic. In this way, a bright color image can be enlarged and projected on the screen.

Also, the liquid crystal projector according to the present invention
Between the light source and the projection lens, parallel white illumination light from the light source is branched into three optical paths, and the white illumination light branched into the three optical paths is emitted from three different directions to a common liquid crystal panel with a microlens array. A branching means, a liquid crystal panel having a group of pixel openings corresponding to the three primary color pixel groups of the color image enlarged and projected on the screen, and a mutually different white color from the branching means provided in the liquid crystal panel from the branching means A liquid crystal panel with a microlens array comprising a microlens array that emits an illuminating light beam to a different group of pixel openings of the liquid crystal panel, and each of three different directions passing through each pixel opening of the liquid crystal panel with a microlens array Are arranged substantially perpendicular to the white light flux of the three primary colors RG
Equipped with three light-resistant dichroic mirrors arranged in order to emit the spectral output obtained by transmitting the B light flux to the projection lens, and without the need for a condenser lens that emits a white light flux with good parallelism. Since the installation accuracy of the three dichroic mirrors as the spectroscopic means does not need to be as high as that of the conventional example, the cost can be reduced.
Using three dichroic mirrors with excellent light resistance as spectroscopy means, illuminate the liquid crystal panel with micro lens array with bright white illumination light up to the limit of light resistance of the liquid crystal panel with micro lens array using a large output light source. Therefore, a stable and brighter color image can be enlarged and projected on the screen.

Thus, the present invention can provide a liquid crystal projector which is economical and can project a bright color image with good image quality on a screen in an enlarged manner.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram of a first embodiment of a liquid crystal projector according to the present invention.

FIG. 2 is an explanatory view of a liquid crystal panel with a microlens array.

FIG. 3 is a diagram illustrating a liquid crystal projector according to a second embodiment of the invention.

FIG. 4 is a schematic configuration diagram of a conventional color liquid crystal display device.

[Explanation of symbols]

1,3 ... liquid crystal projector, 11,21,51 ... light source,
11-1, 12-1, 12-2, 12-3, 12-1 (i), 12-2
(i), 12-3 (i), 21-1, 22-1, 22-2, 22-3... white illumination light flux, 13-1, 13-2, 13-3, 13-1 (i), 1
3-2 (i), 13-3 (i), 23-1, 23-2, 23-3: white luminous flux, 13, 23, 56: liquid crystal with micro lens array, 13L: liquid crystal panel, 13M, 13M ( i), 55 ...
Micro lens array, 14 ... Color absorption filter, 14-
R, 14-G, 14-B, 24-R, 24-G, 24-B ... spectral output, 15, 25, 58 ... projection lens, 16, 26, 59
... Screens, 24R, 24G, 24B, 54R, 54
G, 54B: dichroic mirror, 50: color liquid crystal display device, 52: spherical mirror, 53: condenser lens, field lens 57, R (1) to R (n), G (1) to G (n), B
(1) to B (n): A group of pixel openings.

Claims (2)

[Claims] 1. A liquid crystal projector for enlarging and projecting an image on a liquid crystal panel with a microlens array, which is irradiated with illumination light from a light source, onto a screen by a projection lens, wherein between the light source and the projection lens, A branching unit that branches a parallel white illumination light beam from a light source into three light paths and emits a white illumination light beam from three different directions to a common liquid crystal panel with a microlens array; From the illumination light flux, three primary colors R,
A liquid crystal panel with a microlens array, which forms three white light images having luminance components of the respective G and B images, and emits white light fluxes of the images in three mutually different directions; And a color absorption filter that emits, to a projection lens, a spectral output obtained by spectrally separating the three primary colors R, G, and B from white light beams in three different directions from a panel. LCD projector. 2. A liquid crystal projector for projecting an image on a liquid crystal panel with a microlens array irradiated with illumination light from a light source onto a screen by a projection lens, wherein said projection lens is arranged between said light source and said projection lens. A branching unit that branches a parallel white illumination light beam from a light source into three light paths and emits a white illumination light beam from three different directions to a common liquid crystal panel with a microlens array; From the illumination light flux, three primary colors R,
A liquid crystal panel with a microlens array, which forms three white light images having luminance components of the respective G and B images, and emits white light fluxes of the images in three different directions; 3 is arranged perpendicularly to each of the three different directions of white light flux from the panel.
A liquid crystal projector comprising: three dichroic mirrors that sequentially emit, to a projection lens, spectral outputs obtained by splitting primary colors R, G, and B color light into a projection lens.