| 摘要 |
PROBLEM TO BE SOLVED: To project a distinct image to a screen by preventing irregular color and irregular luminance caused by the difference of the luminance distribution of transmitted light and reflected light due to the characteristic of a dichroic surface. SOLUTION: The projection type image display device 10 is constituted of an illumination optical system 11, a color separation prism 12, reflection type light valves 13R, 13G and 13B, ND filters 14R and 14B, a color composing prism 15 and a projection lens 16. It adopts the arrangement of an off-axis optical system where the optical axis 11a of the illumination optical system 11 is not aligned with a direction perpendicular to the dichroic surfaces 12a and 12b of the color separation prism. The prism 12 color-separates illuminating light from the illumination optical system 11 to R, G and B. The ND filters 14R and 14B correct the difference of the luminance distribution of R and B light beams to make the luminance uniform. The R, G and B light beams whose luminance distributions are made uniform and which are composed by the prism 15 are projected to a screen 17. COPYRIGHT: (C)2006,JPO&NCIPI
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