Projection-type display device

Abstract

A projection-type display device having a single light source which produces light. A first dichroic mirror group receives the light and separates it into colored light. A transmissive light valve system modulates the colored light and a second dichroic mirror group synthesizes the modulated colored light. A projection system projects the synthesized colored light onto a screen.

What is claimed is: 
     
       1. A projection-type display device comprising light source .[.mean.]. .Iadd.means .Iaddend.for producing at least two different colored lights,   at least two transmissive flat-type liquid crystal light valves each having first and second sides,   each .Iadd.of .Iaddend.said transmissive flat-type liquid crystal .[.panel.]. .Iadd.light valves .Iaddend.receiving one of said colored lights through a first side thereof and which modulates said colored lights respectively while said colored lights are passing through said respective transmissive flat-type liquid crystal light valves,   said transmissive flat-type liquid crystal light valves .Iadd.each .Iaddend.including a plurality of picture elements arranged in a matrix array in a predetermined pitch each of which is activated by an active element,   said transmissive flat-type liquid crystal light valves being oriented with respect to one another .Iadd.such that the transmitted modulated colored lights of respective picture elements of each light valve overlap with one another .Iaddend.within a distance substantially equal to or less than said predetermined pitch to superimpose the colored images which emerge from said light valves,   said transmissive .Iadd.flat-type liquid crystal .Iaddend.light valves developing picture images corresponding to said colors passing respectively therethrough,   a dichroic optical element group which directly receives said modulated colored lights emerging from said second sides of said transmissive flat-type liquid crystal .[.panels.]. .Iadd.light valves .Iaddend.and which synthesizes said modulated colored lights,   and projection optical means for directly receiving and then projecting said synthesized colored light.   
     
     
       2. The projection-type display device as claimed in claim 1, wherein said light source means includes a single source of white light. 
     
     
       3. The projection-type display device as claimed in claim 1, wherein said light source means includes a first dichroic optical element group having a first wavelength selecting characteristic, and said dichroic optical element group which directly receives said modulated color lights having a second wavelength selecting characteristic. 
     
     
       4. The projection-type display device as claimed in claim 3, wherein said first and second wavelength selecting characteristics are essentially equal. 
     
     
       5. The projection-type display device as claimed in claim 1, wherein said light source means includes a first dichroic optical element group, said first dichroic optical element group and said dichroic optical element group which directly receives said modulated color lights segregating the light from said light source and synthesizing red, green and blue lights.Iadd..[...]., respectively.Iaddend.. 
     
     
       6. The projection-type display device as claimed in claim 1, wherein said light source means includes a first dichroic optical element group which is arranged in a cross pattern with respect to said dichroic optical element group which directly receives said modulated color lights. 
     
     
       7. The projection-type display device as claimed in claim 1, wherein said transmissive flat-type liquid crystal light valves have a maximum extinction ratio with respect to the main wavelength of the colored light passing therethrough. 
     
     
       8. The projection-type display device as claimed in claim 1, wherein said dichroic optical element group is arranged in a cross .[.state.]. .Iadd.pattern .Iaddend.and at least one of said flat-type liquid crystal light valves is positioned proximate said dichroic optical element group. 
     
     
       9. The projection-type display device as claimed in claim 1, wherein each of said transmissive flat-type liquid crystal light valves has a thickness and a wavelength-light transmittance characteristic and each colored light has a main wavelength, the thickness of each said transmissive flat-type liquid crystal light valves being different from one another such that the main wavelength of each colored light coincides with the wavelengthlight transmittance characteristic of each respective liquid crystal light valve. 
     
     
       10. The projection-type display device as claimed in claim 1, wherein each of the transmissive flat-type liquid crystal light valves are positioned with respect to one another at a distance equal to about one half the pitch of the picture elements. 
     
     
       11. The projection-type display device as claimed in claim 1, wherein said transmissive flat-type liquid crystal light valves are at a focusing position defined as an optically equal distance from said projection optical means. 
     
     
       12. The projection-type display device as claimed in claim 1, wherein each said active element is a TFT element. .Iadd. 
     
     
       13.  The projection-type display device as claimed in claim 1, wherein said transmissive flat-type liquid crystal light valves are oriented such that corresponding picture elements of said transmissive flat-type liquid crystal light valves operatively cooperate with one another. .Iaddend..Iadd.14. The projection-type display device as claimed in claim 1, wherein said transmissive flat-type liquid crystal light valves are oriented such that said transmitted modulated colored lights overlap with one another within a distance substantially equal to or less than said predetermined pitch. .Iaddend..Iadd.15. The projection-type display device as claimed in claim 1, wherein said dichroic optical element group includes two dichroic planes, each dichroic plane having a wavelength selecting characteristic different from the other and said dichroic planes being arranged in a cross pattern. .Iaddend..Iadd.16. The projection-type display device as claimed in claim 1, wherein said dichroic optical element group comprises two dichroic planes, each said dichroic plane having a wavelength selecting characteristic different from the other and said dichroic planes being arranged substantially parallel to each other. .Iaddend..Iadd.17. A projection-type display device comprising: light source means for producing a plurality of different colored lights;   a plurality of transmissive flat-type liquid crystal light valves each having first and second sides,   each of said transmissive flat-type liquid crystal light valve receiving one of said colored lights through the first side thereof as incident light, modulating said incident colored light, and transmitting said modulated colored light,   said transmissive flat-type liquid crystal light valves each including a plurality of picture elements arranged in a matrix array in a predetermined pitch each of which is activated by an active element;   a dichroic optical element group which receives said transmitted modulated colored lights and which synthesizes said transmitted modulated colored lights;   said dichroic optical element group including a plurality of dichroic planes each having a wavelength selecting characteristic different from each other,   each of said plurality of dichroic planes being arranged substantially parallel to each other, a first one of said dichroic planes synthesizing two of said modulated colored lights emerging from two of said transmissive flat-type liquid crystal light valves and a second one of said dichroic planes synthesizing said synthesized transmitted modulated colored light from said first dichroic plane and another of said transmitted modulated colored lights from another of said transmissive flat-type liquid crystal light valves; and   projection means for receiving and then projecting said synthesized   
     
     
        transmitted modulated colored light. .Iaddend..Iadd.18.  The projection-type display device as claimed in claim 17, wherein said transmissive flat-type liquid crystal light valves are arranged so that said plurality of picture elements are oriented such that said transmitted modulated colored lights overlap with one another within a distance substantially equal to or less than said predetermined pitch. .Iaddend..Iadd.19. The projection-type display device as claimed in claim 17, wherein said light source means includes a single light source and a first dichroic optical element group which separates the light from said single light source into red, green and blue lights, and said dichroic optical element group receives said modulated colored lights and synthesizes red, green and blue lights. .Iaddend..Iadd.20. The projection-type display device as claimed in claim 18, wherein said transmissive flat-type liquid crystal light valves are oriented so that corresponding picture elements of said transmissive flat-type liquid crystal light valves operatively cooperate with one another. .Iaddend..Iadd.21. The projection-type display device as claimed in claim 18, wherein said transmissive flat-type liquid crystal light valves are oriented so that said plurality of picture elements cause said modulated color lights transmitted therefrom to overlap with one another within a distance less than said predetermined pitch. .Iaddend..Iadd.22. A projection-type display device comprising: a colored light source producing a plurality of different colored lights;   a plurality of transmissive light valves each modulating a respective one of said plurality of different colored lights;   a light synthesizer synthesizing the plurality of different colored lights modulated by said plurality of transmissive light valves and producing a synthesized light, said light synthesizer including a dichroic plane having a wavelength selecting characteristic; and   a projection lens projecting the synthesized light,   wherein said colored light source, said plurality of transmissive light valves, said light synthesizer and said projection lens are arranged so that optical axes of light fluxes produced by said colored light source and received by said projection lens through said plurality of transmissive light valves and said light synthesizer are positioned substantially coplanar with each other, and so that optical lengths of optical axes of the light fluxes between the respective transmissive light valves and the projection lens are substantially equal to each other.   
     
     
        .Iaddend..Iadd.23.  The projection-type display device as claimed in claim 22, wherein said colored light source comprises a light source emitting a light and a light separator separating the emitted light into said plurality of different colored lights, said light separator including a dichroic plane having a wavelength selection characteristic, and   said light source, said light separator, said plurality of transmissive light valves, said light synthesizer and said projection lens being arranged so that the optical axes of the light fluxes produced from said light source and received by said projection lens through said light separator, said plurality of transmissive light valves and said light synthesizer are positioned substantially coplanar with each other. .Iaddend..Iadd.24. The projection-type display device as claimed in claim 22, wherein said light synthesizer comprises two dichroic planes, each dichroic plane having a different wavelength selection characteristic than the other, said dichroic planes being arranged substantially parallel to each other. .Iaddend..Iadd.25. The projection-type display device as claimed in claim 22, wherein said light synthesizer comprises two dichroic planes, each dichroic plane having a different wavelength selection characteristic than the other and said dichroic planes being arranged in a cross pattern. .Iaddend..Iadd.26. The projection-type display device as claimed in claim 24, wherein said colored light source comprises a light source emitting a light and a light separator separating the emitted light into said plurality of different colored lights,   said light separator including two dichroic planes, each dichroic plane having a different wavelength selection characteristic than the other, and   said two dichroic planes of said light separator being arranged substantially parallel to each other and said two dichroic planes of said light synthesizer being arranged substantially parallel with each other.   
     
     
        .Iaddend..Iadd.27.  The projection-type display device as claimed in claim 25, wherein said colored light source comprises a light source emitting a light and a light separator separating the emitted light by the light source, said light separator comprising two dichroic planes, each dichroic plane of said light separator having a different wavelength selection characteristic than the other, and   said two dichroic planes of said light separator being arranged in a cross pattern and said two dichroic planes of said light synthesizer being arranged in a cross pattern. .Iaddend..Iadd.28. The projection-type display device as claimed in claim 22, wherein each of said transmissive light valves is a transmissive flat-type liquid crystal light valve. .Iaddend..Iadd.29. The projection-type display device as claimed in claim 28, wherein each said transmissive flat-type liquid crystal light valve is an active matrix type transmissive liquid crystal light valve having thin film transistors as active elements. .Iaddend..Iadd.30. The projection-type display device as claimed in claim 23, wherein said light separator includes at least two dichroic planes, and   a first one of said plurality of transmissive light valves modulates a first colored light reflected by a first dichroic plane of said light separator,   a second one of said plurality of transmissive light valves modulates a second colored light reflected by a second dichroic plane of said light separator, and   a third one of said plurality of transmissive light valves modulates a third colored light transmitted through said first and second dichroic   
     
     
        planes of said light separator. .Iaddend..Iadd.31.  The projection-type display device as claimed in claim 30, wherein said light synthesizer includes at least a second dichroic plane, and said modulated first colored light is reflected by a first dichroic plane of said light synthesizer,   said modulated second colored light is reflected by a second dichroic plane of said light synthesizer, and   said modulated third colored light is transmitted through said first and second dichroic planes of said light synthesizer. .Iaddend..Iadd.32. The projection-type display device as claimed in claim 31, wherein said first and second dichroic planes of said light separator and said first and second dichroic planes of said light synthesizer are arranged   
     
     
        substantially parallel with each other. .Iaddend..Iadd.33.  The projection-type display device as claimed in claim 31, wherein said first and second dichroic planes of said light separator are arranged in a cross pattern, and said first and second dichroic planes of said light synthesizer are arranged in a cross pattern. .Iaddend.