PROJECTION OPTICAL DEVICE

摘要

PURPOSE:To easily obtain a high-brightness display and to simplify a projection light source system by guiding light from the projection light source to a light valve by using an off-axis optical system, and diffracting spectrally and multiplexing light from the one projection light source through a dichroic mirror for light valves corresponding to colors. CONSTITUTION:The light emitted by the projection light source 5 is converted by a condenser lens 6 and a reflecting mirror 20 has a diameter larger than the diameter of the spot and reflects the projection light to rotate the direction of the light by 90 deg., obtaining light 100 incident on a lens 14. The projection light from the lens 14 is parallel light 101, which illuminates a dichroic mirror 21 of red. The dichroic mirror 21 reflects only its light component with red wavelength and transmits light components with green and blue wavelength and the light reflected by dichroic mirror 21 illuminates a light valve 4 through a reflecting mirror 24. This light valve 4 is stored with color information on red and reflected light from the light valve 4 travels through the same optical path with the light in the projection in the opposite direction and is reflected by the dichroic mirror 21 to return to the lens 14.