| 摘要 |
PURPOSE:To improve the capacity of a back projection screen and to reduce its cost, by arranging many curved lenses on the light incidence side of a transparent plate and forming optical path correcting lenses on the other face and coating parts other than parts, where the light is converged, of this face with light absorbing material films. CONSTITUTION:Many curved lenses 14 for expanding the region of the visual field are arranged on the light incidence side of the transparent plate, and optical path correcting lenses 12 are formed near parts, where the light passing through curved lenses 14 is converged, on the other face, and parts other than these parts of this face are coated with films of light absorbing materials 13. Optical beams 17 diverged from a video source 15 through a main lens 16 are made incident to curved lenses 14 and are refracted and are converged near optical path correcting lenses 12. They are refracted again by optical path correcting lenses 12 and are transmitted to the spectator side after correction of the optical path. In case of the optical path of oblique projection in the use of the half of this screen 11, the light is hardly made incident to light absorbing materials 13 and corners 8 to be lost, and the effect similar to the projection from the front is obtained. |
