Back projection apparatus
AssigneeSony Corporation
InventorsNorio Itoh, Masayuki Omori
Life of this patent
Estimating the term…
Abstract
Three cathode ray tubes are provided for projecting and converging three different primary color images on a back projection screen. The back projection screen has a first cylindrically lenticulated face facing toward the cathode ray tubes for determining a viewing angle of the screen and a second cylindrically lenticulated face on the opposite side thereof for arranging in parallel the emergent light axes of three luminous fluxes respectively projected from the three cathode ray tubes. Color shading of the color image projected on the screen which would be caused by convergence of the three light axes extending from the cathode ray tubes is eliminated by the second cylindrically lenticulated face of the screen.
Claims7
A back projection apparatus for displaying a color image comprising
- a screen including a light-transmitting screen member having lenticulated front and rear faces;
- a plurality of spaced apart color image sources disposed in back of said screen and producing a plurality of respective color images of different colors;
- and
- projection lens means disposed between said color image sources and said screen for projecting said plurality of different color images from said spaced apart sources thereof along convergent optical paths to said rear face of the screen member;
- said rear face of the screen member being constituted by lenticular lenses with the thickness of said screen member between said front and rear faces thereof and the radial curvature of said lenticular lenses being dimensioned to focus said different color images substantially at said front surface of the screen member and to provide a predetermined viewing angle of the resulting composite color image on the screen, and said front face of the screen member being constituted by lenticular lenses having a radial curvature which causes said optical paths of the projected different color images, on emerging from said front face, to be in parallel relation to each other for preventing color shading of said composite color image.
Dependencies are inferred from the claim text.