PROJECTION DISPLAY DEVICE

PROBLEM TO BE SOLVED: To provide a projection display device which eliminates the need for a lens driving mechanism and has a focusing mechanism performing a focus varying operation by a liquid crystal lens at low temperature without consuming any special electric power to heat the liquid crystal lens. SOLUTION: The projection display device 1 roughly includes a light source 10, a light guide 20 which makes the luminance of light from the light source 10 uniform, a polarization beam splitter 30 which performs polarization conversion on the light, a liquid crystal light valve 40 which modules the light to compose an image, a projection lens 50 which enlarges and projects the image composed by the liquid crystal light valve 40 on a screen, the liquid crystal lens 60 which adjusts the focus of the image, a heat conductive holder 70 which conducts heat generated by the light source 10 to the liquid crystal lens 60, a temperature sensor 90 which detects surface temperature of the liquid crystal lens 60, and a cooling fan 80 which adjusts the heat conducted to the heat conductive holder 70 according to a temperature value detected by the temperature sensor 90. COPYRIGHT: (C)2009,JPO&INPIT