LIQUID CRYSTAL PROJECTION TYPE IMAGE DISPLAY DEVICE

摘要

PURPOSE:To efficiently utilize illumination light by a projection optical system which has a small field angle and a small aperture ratio by diffracting the illumination light transmitted through a display plate almost at right angles to a liquid crystal display plate and also converging the light nearly on the entrance pupil of the projection optical system. CONSTITUTION:An image formed with the illumination light transmitted through the display plate 1 is formed nearby the entrance pupil of a projection lens 2, so the bright image having no scatter of the illumination light beam is obtained when the diameter of the lens 2 is larger than the image. The illumination light transmitted through the display plate 1 is refracted at right angles to the display plate 1 and the lens 2 is arranged on its prolongation, so the center of the display plate 1 is aligned with the optical axis of the lens 2. Consequently, the image cycle of the projection lens is sufficient only on condition that the image surface size of the display plate 1 is covered.