Patent ID: 8123364
Filing Date: 2012-02-28
Classification: G03B

Abstract:
1. A rear-projection type display apparatus, comprising: a fresnel screen; a projection unit which projects irradiating light from a light source unit onto the fresnel screen through a light valve; a light measurement unit located at a position where reflected light from the fresnel screen is condensed and configured to measure the reflected light; and a control unit adapted to control the light valve on the basis of a measurement result obtained by said light measurement unit, wherein a surface of the fresnel screen facing inward of the apparatus has a prism group and the prism group has a concentric arrangement configured to transmit a first part and to reflect a second part of the irradiating light projected onto the fresnel screen, and wherein only the reflected light from the surface of the prism group is condensed at the position of the light measurement unit and the transmitted light is transmitted via the surface of the prism group such that total internal reflection occurs in the a direction of a viewer.