Rear projection apparatus

Claim 1

A rear projection apparatus for displaying a color image comprising: red, green and blue color image sources located horizontally to each other in this order for producing respective color images of different colors; projection lenses located respectively in front of said image sources for projecting light fluxes from said respective image sources along converging optical paths; and a screen located at convergent points of said projected light fluxes and including a light-transmitting lenticular sheet having an input surface and an exit surface for the projected light fluxes; said input surface of the lenticular sheet being constituted by diffusing lenticular profiles having a ratio of lenticulated depth X v to close-axis-curvature radius R 1 (X v /R 1 ) which is within a range of 0.5 to 1.8, said profiles being prolonged along the optical axis and constituting aspherical input lenticular lenses, said lenticular sheet having a thickness of approximately ##EQU31## times said radius R 1 where n is refractive index of a material of said sheet, said aspherical input lenticular lenses refracting projected input light flux of the red color and the blue color having a path extending at an angle to the normal of said screen in such a way as to provide coma aberration at said exit surface of the lenticular sheet, said exit surface of the lenticular sheet having output lenticular lenses extending in the same direction as said input lenticular lenses and having light-stopping black stripes incorporated thereon and extending in parallel with said input lenticular lenses, said output lenticular lenses refracting light flux of the red color and the blue color in accordance with said coma aberration formed thereon, whereby a center light flux of input light at an angle to the normal of said screen projected at center portions of said input lenticular lenses is refracted by a larger amount in view of the difference between the red color and the blue color than the amount of refraction of other light flux projected close to valley portions of said input lenticular lenses, thereby making an output light flux corresponding to said input center light flux not parallel to each other but shifted in opposite directions by an amount substantially proportional to said depth X v of said input lenticular profiles, said black stripes being located at an area where substantially no efficient light flux exits.