JP2532375B2 - Color LCD projector - Google Patents

Description

Description: TECHNICAL FIELD OF THE INVENTION The present invention relates to a color liquid crystal projector.

[Technical background of the invention and its problems]

The liquid crystal projector uses a transmissive dot matrix liquid crystal display panel, and illuminates the liquid crystal display panel from the rear side thereof to project a display image of the liquid crystal display panel (such as a television image) on a screen surface by a projection lens. Therefore, according to this liquid crystal projector, a display image on a small liquid crystal display panel can be greatly enlarged and viewed.

This liquid crystal projector includes one that projects a monochrome image and one that projects a color image. Conventionally, a color liquid crystal projector that projects a color image is one color liquid crystal that displays a full color image as a liquid crystal display panel. A display panel is known. This color liquid crystal display panel is one in which three color filters of red, green and blue are alternately arranged corresponding to each pixel display section, and the color filters are generally electrodes (scan electrodes or signal electrodes) of the liquid crystal display panel. Electrodes).

However, since this color liquid crystal display panel combines one color pixel with three pixels of red, green, and blue displayed adjacently, the resolution is 1/1 of that of a monochrome display type liquid crystal display panel. The color liquid crystal projector using this color liquid crystal display panel had a problem that the projected image on the screen was rough.

For this reason, recently, three transmissive dot matrix liquid crystal display panels are used to display a red image, a green image, and a blue image on each of the liquid crystal display panels, and display images of each color of the respective liquid crystal display panels are displayed. A so-called three-lens type color liquid crystal projector has been considered in which a projection lens is used to project an image on a screen surface so that a color image is combined on the screen surface. That is, in this trinocular color liquid crystal projector, only the red image is displayed on the first liquid crystal display panel, only the green image is displayed on the second liquid crystal display panel, and the third liquid crystal display panel is displayed. It is designed to display only a blue image. By doing so, the resolution of each liquid crystal display panel can be increased, so that the display image of each color of each liquid crystal display panel is superimposed on the screen surface to form one color. The resolution of the screen projection image combined with the image can be increased.

In this trinocular color liquid crystal projector, each liquid crystal display panel is provided with red, green, and blue color filters (the first liquid crystal display panel has a red color filter and the second liquid crystal display panel has a red color filter). Is a green color filter,
The third liquid crystal display panel is provided with a blue color filter), and the white light from the white light source is focused by the color filters to display red, green, and blue color images on each liquid crystal display panel. The white light from the white light source is colored into red, green and blue by the color filters respectively, and the light of each color is made incident on each liquid crystal display panel and a red, green and blue color image is formed on each liquid crystal display panel. It is considered that the display is made. The three-lens type color liquid crystal projector is provided with a light source for each liquid crystal display panel, and one light source is used and the light flux from this light source is divided into three and made incident on each liquid crystal display panel. However, it is generally costly to provide a light source for each liquid crystal display panel. Therefore, in general, one light source is used and the light flux from this light source is divided into three and made incident on each liquid crystal display panel. Is said to be advantageous.

However, the color liquid crystal projector described above colors the white light from the white light source by absorbing the specific wavelength light of the color filter, so that about 70% or more of the light energy is absorbed in the color filter. As a result, the screen projection image becomes considerably dark, so that in order to obtain a screen projection image with sufficient brightness, the light emission energy of the light source must be three times or more that of the liquid crystal projector that projects a black and white image. This is also true of the color liquid crystal projector using the above-mentioned one color liquid crystal display panel.

[Object of the Invention]

The present invention has been made in view of the above circumstances, and an object thereof is to reduce a loss of light energy and to display a color image of a sufficient brightness without increasing the light emission energy of a light source. An object is to provide a color liquid crystal projector capable of projecting on a plane.

[Outline of Invention]

That is, the color liquid crystal projector of the present invention includes a light source, a spectroscopic unit that separates light from the light source into red light, green light, and blue light, and red light, green light, and blue light that are separated by the spectroscopic unit. A reduction lens that reduces the width of each light flux, a mirror that draws each light flux whose width has been reduced, a magnifying lens that magnifies the width of each light flux that is drawn by this mirror, and a width that is magnified by this magnifying lens. Is provided with a liquid crystal on which each of the expanded light beams enters, and a projection lens for projecting the light passing through the liquid crystal.

According to this invention, since the light from the light source is incident on the spectroscopic means to obtain the red light, the green light, and the blue light, most of the effective light from the light source can be used as light.
It is possible to reduce a loss of light energy as compared with an apparatus using a color filter that absorbs light of a specific wavelength, and to project a color image with sufficient brightness without increasing the emission energy of the light source.

Example of Invention

An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 schematically shows the overall structure of the color liquid crystal projector. In the figure, 1a, 1b and 1c are three transmissive dot matrix liquid crystal display panels, and 2a, 2b and 2c are each liquid crystal display panel 1a, The three projection lenses are arranged in front of 1b and 1c, respectively, and the liquid crystal display panels 1a, 1b and 1c and the projection lenses 2a, 2b and 2c are arranged to face the screen 3 respectively.

On the other hand, in FIG. 1 and FIG. 2, 4 is one white light source commonly used as an illumination light source of each liquid crystal display panel 1a, 1b, 1c, and this white light source is a white tube straight fluorescent lamp. It is composed of a light source lamp 5 and a horizontally long reflector 6 that reflects and condenses the white light A from the light source lamp 5 to the front. Although one light source lamp 5 is shown in the drawing, a plurality of light source lamps 5 may be provided in the reflector 6 in parallel.

Reference numeral 7 denotes a laterally long light flux correction lens that corrects the narrow striped light flux a reflected and condensed by the reflector 6 into a parallel light flux. The striped light flux a converted into a parallel light flux by the light flux correction lens 7 is The light beam width is further reduced by the horizontally long light beam width reducing lens 8 and is incident on the horizontally long optical prism 9.

This prism 9 is for spectrally splitting transmitted light by a light dispersion effect, like a general optical prism.
The white light that has been made into a striped light beam a and is incident on this prism 9 is spectrally dispersed by this prism 9. The striped light flux a spectrally separated by the prism 9 is roughly divided into a light flux R in the red region, a light flux G in the green region, and a light flux B in the blue region.

Further, in FIG. 1, reference numeral 10 designates a spectrally dispersed striped luminous flux a which spreads through the prism 9 and spreads, and is divided into a red region light R, a green region light G and a blue region light B. It is a light beam splitting lens array.
This luminous flux splitting lens array 10 is an array in which three laterally long convex lenses 10a, 10b, 10c are arranged in parallel and continuously arranged corresponding to the red area, green area and blue area of the striped luminous flux a, respectively. The light R, G, B of each color region of the striped luminous flux a passes through each convex lens 10a, 10b, 10c of the luminous flux splitting lens array 10, and each convex lens 10a, 10b
The luminous flux width is reduced by b and 10c, and the luminous flux is divided into three stripe luminous fluxes of red region light R, green region light G, and blue region light B. The red region light R and the green region light G
Since the blue area light B and the blue area light B are obtained by spectrally dispersing white light, the three color area lights R, G, B become white light if they are mixed as they are.

Reference numeral 11 denotes a light flux correction lens array that corrects the red region light R, the green region light G, and the blue region light B, which are split into three striped light fluxes by the light flux splitting lens array 10, into parallel light fluxes. This light flux correction lens array
Reference numeral 11 denotes three horizontally long convex lenses 11a, 1 corresponding to the lights R, G, B of the respective color regions divided into the three striped light fluxes.
1b and 11c are arranged side by side in parallel, and the light R, G, of each of the color regions is divided into three striped luminous fluxes.
B is each concave lens 11 of the light flux correction lens array 11.
After passing through a, 11b, and 11c, the concave lenses 11a, 11b, and 11c correct the light beams into parallel light beams.

Then, of the lights R, G, B of the respective color regions, the red region light R is one of the three liquid crystal display panels 1a, 1b, 1c by the horizontally long reflection plate 12a arranged as shown in FIG. The green region light G is reflected toward the first liquid crystal display panel 1a, the green region light G is reflected toward the second liquid crystal display panel 1b by the horizontal reflection plates 12b, 12b, and the blue region light B is reflected by the horizontal reflection plates 12c, 12c. Third
Is reflected toward the liquid crystal display panel 1c.

Then, the lights R, G, B in the respective color regions reflected toward the respective liquid crystal display panels 1a, 1b, 1c are respectively reflected by the light flux width expanding lens 13
The light flux width is expanded by a, 13b, 13c, and when the light flux width is expanded to the width of the display area of the liquid crystal display panels 1a, 1b, 1c, the light flux correction lenses 14a, 14b, 14c convert the light fluxes into parallel light fluxes and each liquid crystal Light incident on the display panels 1a, 1b, 1c and transmitted through the respective liquid crystal display panels 1a, 1b, 1c, that is, image light in the red region displayed by the first liquid crystal display panel 1a and the second liquid crystal display panel 1b The image light in the green area displayed by and the image light in the blue area displayed by the third liquid crystal display panel 1c are magnified by the projection lenses 2a, 2b, 2c, respectively, and an image of three colors is displayed on the screen 3 surface. The lights are projected so as to overlap each other, and a color image formed by combining image lights of three colors of red, green, and blue is formed on the screen 3 of the screen.

That is, this color liquid crystal projector spectrally separates the white light A from the white light source 4 by the prism 9 and divides it into light R in the red region, light G in the green region, and light B in the blue region. Light R, G, B is incident on each of the three liquid crystal display panels 1a, 1b, 1c, and each liquid crystal display panel 1
A red image, a green image, and a blue image are displayed on a, 1b, and 1c, and the red image, the green image, and the blue image are projected onto the screen 3 to synthesize a color image. According to the liquid crystal projector, the white light source 4
From the light source 4 to each liquid crystal display panel 1a, 1b, 1c, since the white light A from is spectrally dispersed by the prism 9 to obtain the lights R, G, B in the red, green, and blue color regions. Attenuation of light energy generated in the optical path of is also extremely slight due to each lens, the reflection plate, and the prism 9. Therefore, most of the white light A from the light source 4 is converted into the light R, G, B of each color region. Since it can be made to enter each liquid crystal display panel 1a, 1b, 1c, there is no large loss of light energy due to absorption of light of a specific wavelength of the color filter as in the case of using a color filter. It is possible to project a color image with sufficient brightness on the screen surface without increasing the light emission energy of the light source by reducing the loss of light.

Furthermore, since the light flux of the white light A from the reflector 6 is reduced by the light flux correction lens 7 and the light flux compression lens 8, a large light source with a rich light quantity can be used, and the light flux from the light source is not wasted. , Light can be used effectively.

In the above embodiment, the striped luminous flux a spectrally dispersed by the prism 9 is constrained and divided into a lens array.
The light R, G, B of each color region of red, green, and blue is divided by 10 and the light R, G, B of each color region of this striped light flux a is divided.
Is divided into striped luminous flux a, its red region light R
The green area light G and the blue area light B in different directions 3
It may be performed by reflecting the light with a reflecting plate of a surface, or may be a three-sided horizontal concave mirror portion (even a normal concave mirror is parallel to the red area, the green area, and the blue area of the striped light beam a). A striped light beam a is reflected by a reflecting mirror in which a sawtooth concave mirror similar to a Fresnel lens is formed in parallel, and the striped light beam a is divided into red region light R, green region light G, and blue region light B. You may do it. Further, in the above embodiment, the white light A from the white light source 4 is converted into parallel narrow stripe light flux a by the light flux correction lens 7, and then the width of the striped light flux a is further reduced by the light flux width reduction lens 8. Although the light beam correcting lens 7 is not necessary, the lens system that makes the white light A from the light source 4 into a narrow striped light beam a and the striped light beam a is made incident. The divided luminous flux of each color area is divided into liquid crystal display panels 1a, 1
The means for making each of b and 1c incident is not limited to the above embodiment.

〔The invention's effect〕

A color liquid crystal projector of the present invention includes a light source, a spectroscopic unit that separates the light from the light source into red light, green light, and blue light, and red light, green light, and blue light that are separated by the spectroscopic unit. A reduction lens that reduces the width of the light flux, a mirror that guides each of the light fluxes whose width has been reduced, a magnifying lens that magnifies the width of each light flux that is routed by this mirror, and a width that is magnified by this magnifying lens. It is characterized in that it is provided with a liquid crystal into which the respective luminous fluxes respectively entered and a projection lens for projecting light passing through the liquid crystal.

According to this invention, since the light from the light source is incident on the spectroscopic means to obtain the red light, the green light, and the blue light, most of the effective light from the light source can be used as light.
It is possible to reduce a loss of light energy as compared with an apparatus using a color filter that absorbs light of a specific wavelength, and to project a color image with sufficient brightness without increasing the emission energy of the light source. Further, a light splitting lens array that further divides the red light, the green light, and the blue light separated by the spectroscopic means by further reducing the width of each light flux, a mirror that circulates each light flux whose width has been reduced, and a mirror The light magnifying lens that expands the width of each of the drawn light beams facilitates the distribution of each light beam, so that each light beam can be favorably incident on the liquid crystal and miniaturization can be realized.

[Brief description of drawings]

1 and 2 are a schematic configuration diagram of a color liquid crystal projector showing an embodiment of the present invention and an enlarged perspective view of a light source side portion thereof. 1a, 1b, 1c …… Transmissive dot matrix liquid crystal display panel, 2a, 2b, 2c …… Projection lens, 3 …… Screen, 4…
... White light source, 5 ... White light source lamp, 6 ... Reflector, 7 ... Light flux correction lens, 8 ... Light flux width reduction split lens, 9 ... Optical prism, 10 ... Light flux split lens array, 11 ... Light flux Compensation lens array, 12a, 12b, 12c …… Reflector, 13a, 13b, 13c …… Luminescent beam expansion lens, 14a, 14b, 14c
...... Light flux correction lens, A ... White light, a ... Striped light flux, R ... Red area light, G ... Green area light, B ...
Blue area light.

Claims (1)

(57) [Claims] 1. A light source, a spectroscopic unit that separates the light from the light source into red light, green light, and blue light, and each of the red, green, and blue light beams separated by the spectroscopic unit. A reduction lens that reduces the width, a mirror that guides each of the light fluxes whose width has been reduced, a magnifying lens that magnifies the width of each light flux that is routed by this mirror, and a width that is magnified by this magnifying lens. A color liquid crystal projector comprising: a liquid crystal into which each light flux is incident; and a projection lens which projects light through the liquid crystal.