Patent ID: 6621530
Filing Date: 2003-09-16
Classification: G02B,H04N

Abstract:
A projection television, comprising:a plurality of image projectors for respective images of different colors, wherein each image projector has an axis of projection, wherein any two adjacent image projectors define a pair of image projectors, and wherein each pair of image projectors have axes of projection defining an angle of incidence; a projection screen formed by at least one hologram disposed on a substrate superimposed on at least one light transmissive panel, said screen receiving images from said projectors on a first side and displaying said images on a second side with controlled light dispersion of said displayed images; at least one mirror along an optical path between the projectors and the projection screen, the at least one mirror being oriented to reflect images from the projectors onto said first side, defining an angle of projection for each image within a range of approximately Â±30Â° relative to an axis orthogonal with the screen; said projection screen redirecting the images reflected thereon such that the images displayed on said second side are directed at an angle of display within a range of display angles relative to the axis orthogonal with the screen; said screen forming an interference array with optical properties varying horizontally and vertically across a field of view, the screen having a color shift less than or equal to approximately five for all said angles of projection in said range, as determined by the maximum value obtained from at least one of the following expressions: C&af;(Î¸)=20&CenterDot;log10&af;(red&af;(Î¸)blue&af;(Î¸))C&af;(Î¸)=20&CenterDot;log10&af;(green&af;(Î¸)blue&af;(Î¸)),&thgr; is any angle within said range of horizontal viewing angles, C (&thgr;)is the color shift at angle &thgr;, red (&thgr;) is the red luminance level at angle &thgr;, blue (&thgr;) is the blue luminance level at angle &thgr; and green (&thgr;) is the green luminance level at angle &thgr;.