JPS62150383A - Color liquid crystal projector - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a color liquid crystal projector.

[Technical background of the invention and its problems]

A liquid crystal projector uses a transmissive dot matrix liquid crystal display panel, illuminates the liquid crystal display panel from the back side, and enlarges and projects the image displayed on the liquid crystal display panel (for example, a television image) onto the screen surface using a projection lens. According to this liquid crystal projector, an image displayed on a small liquid crystal display panel can be greatly enlarged and viewed.

There are two types of liquid crystal projectors: those that project black-and-white images and those that project color images. Conventionally, color liquid crystal projectors that project color images have a single color liquid crystal display panel that displays full-color images. One that uses a display panel is known. This color liquid crystal display panel has red and red colors corresponding to each pixel display section.
Three color filters of green and blue are arranged alternately, and color filters are generally provided on electrodes (scanning electrodes or signal electrodes) of a liquid crystal display panel.

However, since this color liquid crystal display panel synthesizes one color pixel by three pixels of red, green, and blue that are displayed adjacently, the resolution is 1/1 of that of a black and white display type liquid crystal display panel. /3, and as a result, color liquid crystal projectors using this color liquid crystal display panel had the problem that the projected image on the screen became 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 liquid crystal display panel, and the displayed image of each color on each liquid crystal display panel is A so-called three-lens color liquid crystal projector is being considered, which uses projection lenses to project images one on top of the other on a screen surface to synthesize a color image on the screen surface. In other words, this three-lens color liquid crystal projector displays only a red image on the first liquid crystal display panel, only displays a green image on the second liquid crystal display panel, and displays only a green image on the third liquid crystal display panel. It is designed to display only the blue image, and if you do this like this,
Since the resolution of each liquid crystal display panel can be increased, it is possible to increase the resolution of a screen projected image in which the display images of each color of each liquid crystal display panel are superimposed on the screen surface and combined into one color image.

This three-lens color liquid crystal projector is equipped with red, green, and blue color filters for each liquid crystal display panel (the first liquid crystal display panel has a red color filter, the second liquid crystal display panel has a red color filter, and the second liquid crystal display panel has red, green, and blue color filters). (A green color filter is provided on the third LCD panel, and a blue color filter is provided on the third LCD panel.)
, the white light from the white light source is colored by color filters so that red, green, and blue color images are displayed on each liquid crystal display panel, and the white light from the white light source is colored by color filters to display red, green, and blue color images on each liquid crystal display panel. It is considered that the liquid crystal display panel is colored green and blue, and the light of each color is made incident on each liquid crystal display panel to display a red, green, and blue color image on each liquid crystal display panel. Note that this three-lens color LCD projector includes one that has a light source for each LCD panel, and one that combines a single light source and divides the luminous flux from this light source into three parts to enter each LCD panel. However, providing a light source for each liquid crystal display panel would be costly, so a method is generally used in which a single light source is used and the luminous flux from this light source is divided into three and incident on each liquid crystal display panel. Things are said to be advantageous.

However, since the color liquid crystal projector mentioned above colors the white light from the white light source by absorbing light of a specific wavelength in the color filter, approximately 70% or more of the light energy is absorbed by the color filter. As a result, the projected image on the screen becomes quite dark, so in order to obtain a projected image on the screen with sufficient brightness, the emission energy of the light source had to be more than three times that of a liquid crystal projector that projects a black and white image.

Note that this also applies to the aforementioned color liquid crystal display panel using one color liquid crystal display panel.

[Purpose of the invention]

This invention was made in view of the above-mentioned circumstances, and its purpose is to reduce the loss of light energy and to display a color image of sufficient brightness on a screen without increasing the light emitting energy of the light source. To provide a three-lens color liquid crystal projector capable of projecting onto a surface.

(Summary of the Invention) That is, the present invention includes one white light source as a light source, and transmits the white light from the white light source in a narrow width between this white light source and three transmissive dot matrix liquid crystal display panels. A lens system that produces a striped light beam, an optical prism that allows the striped light beam to pass through, and the striped light beam that is spectrally separated by the prism into red region light, green light light, and blue region light. A means for dividing the luminous flux of each color region and making it incident on each of the liquid crystal display panels is provided.

In other words, in this invention, white light from a white light source is spectrally divided by a prism into light in the red region, light in the green region, and light in the blue region, and the light in each color region is divided into three liquid crystal display panels. According to this invention, the white light from the white light source is spectrally separated by a prism to display red, green, and red images on each liquid crystal display panel. Since the system is designed to obtain light in the blue color range, most of the white light from the light source can be converted into light in each color range and then incident on each LCD panel, similar to when using color filters. Since there is no large loss of light energy due to absorption of light of a specific wavelength by the color filter, the loss of light energy is reduced and a color image of sufficient brightness is projected onto the screen surface without increasing the light emission energy of the light source. be able to.

[Embodiments of the invention]

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

Figure 1 schematically shows the overall configuration of a 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. ) I, r 1 a, 1 b.

Three projection lenses are respectively arranged in front of the LCD panel 1C, and each of the liquid crystal display panels 1a and 1b.

1C and projection lenses 2a, 2b, and 2c are arranged to face the screen 3, respectively.

On the other hand, in FIGS. 1 and 2, reference numeral 4 denotes one white light source that is shared as an illumination light source for each of the liquid crystal display panels 1a, 1b, and 1c, and this white light source 4 is composed of a straight tube fluorescent lamp. A white light source lamp 5 and a horizontally long glue deflector 6 that reflects and focuses the white light A from the light source lamp 5 forward.
It consists of Although the drawing shows one light source lamp 5, this light source lamp 5 has a plurality of reflectors 6.
It may be provided in parallel inside.

Further, 7 is a horizontally 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, and the striped light flux a converted into a parallel light flux by the light flux correction lens 7 is The light beam is roughly reduced by a horizontally long light beam reducing lens 8 and then enters a horizontally long optical prism 9 .

This prism 9, like a general optical prism, spectrally separates the transmitted light by the light dispersion effect, and the white light incident on this prism 9 as a striped light beam a is spectrally separated by this prism 9. Ru.

The striped light beam a that has been spectrally separated by the prism 9 can be roughly divided into a rainbow-like light beam in which light R in the red region, light G in the green region, and light B in the blue region are continuously arranged.

In FIG. 1, reference numeral 10 divides the spectrum-divided striped light beam a, which passes through the prism 9 and spreads, into three parts: red region light R, green region light G, and blue region light B. This is a beam splitting lens array.

This beam splitting lens array 10 is constructed by continuously arranging three horizontally long convex lenses 10a, 10b, and 10c in parallel in correspondence with the red region, green region, and blue region of the striped light beam a, respectively. The lights R, G, and B of each color region of the striped light flux a are transmitted through the respective convex lenses 10a, 10b, and 10c of the light flux splitting lens array 10, respectively.
Through these convex lenses 10a, 10b, and 10c, the light flux is reduced into red region light R, green region light G,
The blue region light B is divided into three striped light beams. Note that this red region light R, green region light G, and blue region light B are obtained by spectrally dispersing white light, so these three color region lights R, G, and B can be obtained as they are. When mixed together, white light is produced.

Reference numeral 11 denotes a beam correction lens array that corrects the red area light R, green area light G, and blue area light B, which have been divided into three striped beams by the beam splitting lens array 10, into parallel beams, respectively. This luminous flux correction lens array 11 divides the R and G lights of each color region into three striped luminous fluxes.

Three horizontally long convex lenses 11a, 1 corresponding to B, respectively.
1b and 11c are arranged in parallel, and the lights R, G, and B of each color region, which are divided into three striped light fluxes, are transmitted through the respective concave lenses 118° 11b and 11c of the light flux correction lens array 11, respectively. through each concave lens 11a.

11b and 11c correct the beam into a parallel beam.

Of the lights R, G, and B in each color region, the red region light R is transmitted to a horizontally long reflecting plate 12 arranged as shown in FIG.
a toward the first liquid crystal display panel 1a of the three liquid crystal display panels Ia, 1b, and 1G, and the green area light G is reflected by the horizontally long reflecting plates 12b and 12b toward the second liquid crystal display panel 1b. The blue region light B is reflected by the horizontally elongated reflecting plates 12G and 12C to the third liquid crystal display panel 1C.
reflected towards.

Then, the light R, G, and B of each color region reflected toward each liquid crystal display panel 1a, 1b, and 1c are enlarged in the light flux by magnifying lenses 13a, 13b, and 13c, respectively, and the light flux is displayed on the liquid crystal display panel. When the display area of panels 1a, 1b, and 1G has been expanded to the width, the luminous flux correction lens 148
．． 14b.

14C into a parallel light beam, each liquid crystal display panel 1a,
1b, 1c, each liquid crystal display panel 1a, 1b,
The light transmitted through the lc, that is, the image light in the red region displayed by the first liquid crystal display panel 1a, the image light in the green region displayed by the second liquid crystal display panel 1b, and the image light in the green region displayed by the third liquid crystal display panel 1C. The displayed image light in the blue region is magnified by the projection lenses 2a, 2b, and 2c, respectively, and projected onto three screens so that the three colors of image light overlap each other, and red, green, and blue image lights are projected onto the three screens. A color image is formed by combining three colors of image light.

That is, this color liquid crystal projector uses a white light source 4.
A prism 9 spectrally spectrally spectra white light A emitted from the screen, dividing it into light R in the red region, light G in the green region, and light B in the blue region. Display panels 1a and 1b.

1C and each liquid crystal display panel la.

This color liquid crystal projector displays a red image, a green image, and a blue image on 1b and 1c, and projects the red image, green image, and blue image onto three screens to synthesize a color image. According to the above, since the white light A from the white light source 4 is spectrally separated by the prism 9 to obtain lights R, G, and B in the red, green, and stomach color regions, each liquid crystal display from the light source 4 is Panels 1a, 1b, 1G
The attenuation of the light energy that occurs on the optical path up to the point is only a very small attenuation due to each lens, reflection plate, and prism 9, and therefore most of the white light A from the light source 4 is converted into light R, G, and B of each color region. Because it can be changed and made incident on each liquid crystal display panel ``LA, 1B, JC'',
Unlike when using a color filter, there is no large loss of light energy due to absorption of light of a specific wavelength by the color filter. Therefore, the loss of light energy is reduced and sufficient brightness is achieved without increasing the light emission energy of the light source. color images can be projected onto the screen surface.

In the above embodiment, the striped light beam a that has been spectrally separated by the prism 9 is transferred to the light beam splitting lens array 1.
The light R, G, and B of each color region of red, green, and blue are divided by o, and the light R of each color region of this striped light flux a is
. Alternatively, three horizontally elongated concave mirrors (ordinary concave mirrors or serrated concave mirrors similar to parallel Fresnel lenses may be used) may be arranged in parallel to correspond to the red region, green region, and blue region of the striped light beam a, respectively. The striped light beam a may be reflected by a reflecting mirror formed in the above-described configuration, and the striped light beam a may be divided into red region light R, green region light G, and blue region light B. Furthermore, in the above practical example, the white light A from the white light source 4 is transformed into a parallel narrow striped light flux a by the light flux correction lens 5, and the width of the striped light flux a is further reduced by the light flux medium reduction lens 7. However, the light flux medium reduction lens 7 may be omitted, and a lens system that converts the white light A from the light source 4 into a narrow striped light flux a, and a striped light flux may be used. The means for causing the luminous flux of each color region obtained by dividing a into each of the liquid crystal display panels 1a, 1t) and 1C is not limited to the above embodiment.

〔Effect of the invention〕

This invention provides a lens system that includes one white light source as a light source and that converts the white light from the white light source into a narrow striped light beam between the white light source and three transmissive dot matrix liquid crystal display panels. and an optical prism that transmits this striped light beam, and divides the striped light beam that has been spectrally separated by this prism into three parts: red light, green light, and blue light, and produces a light beam in each color range. Since the device is provided with means for causing the light to enter each of the liquid crystal display panels, it is possible to reduce the loss of light energy and project a color image with sufficient brightness onto the screen surface without increasing the light emission energy of the light source. I can do it.

[Brief explanation of drawings]

FIGS. 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 the light source side portion thereof. 1a, 1b, IC... 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... Luminous flux correction lens, 8... Luminous flux medium reduction division lens, 9... Optical prism, 10... Luminous flux splitting lens array, 11... Luminous flux correction lens a L/-1', 12a, 12b, 12C...
・Reflector plate, 13a, 13b, 13cm beam width expansion lens, 14a, 14b, 14c... Luminous flux correction lens, A・
... White light, a... Striped light flux, R... Red area light, G... Green area light, B... Blue area light.

Claims (1)

[Claims] Three transmissive dot-matrix liquid crystal display panels are used to display a red image, a green image, and a blue image on each liquid crystal display panel, and each color display image of each liquid crystal display panel is projected onto the screen surface using a projection lens. A three-lens color liquid crystal projector that synthesizes a color image on a screen by superimposing a color image on the screen is equipped with one white light source as a light source, and a light source from the white light source is provided between the white light source and the liquid crystal display panel. A lens system that converts white light into a narrow striped light beam, an optical prism that transmits this striped light beam, and the striped light beam that is spectrally divided by this prism into red region light, green light, and blue region light. 2. A color liquid crystal projector comprising means for dividing the light into three parts and making each of the light beams of each color region enter each of the liquid crystal display panels.