Patent ID: 6573950
Filing Date: 2003-06-03
Classification: G02B,G03B,H04N

Abstract:
A transmission type screen used for a projection type image display unit for expanding and projecting images on said screen with the use of an optical lighting system provided with means for separating white light flux from a white light source into three primary color light fluxes of red, green, and blue and irradiating each of those three primary color light fluxes on a display element at an angle different from the others and projection lens unit means for projecting said three primary color light fluxes of red, green, and blue modulated by said display element; whereinsaid optical lighting system and said projection lens unit are disposed between said white light source and said display element; said transmission type screen comprises: a first sheet of said transmission type screen in the form of a Fresnel lens sheet having at least one Fresnel lens surface; a second sheet in the form of a lenticular lens sheet consisting of a plurality of first lenticular lenses formed respectively so that the lens surface at the image display element side is shaped longer in the vertical direction of said screen and a plurality of second lenticular lenses disposed continuously in the horizontal direction of said screen so as to almost face said first lenticular lens and formed respectively so that the lens surface at its image viewing side is shaped longer in the vertical direction of said screen respectively; and a third sheet provided with filtering characteristics for absorbing a color light emitted with the strongest spectrum from said white light source.