ILLUMINATION UNIT AND A PROJECTION-TYPE IMAGE DISPLAY DEVICE HAVING THE SAME, PARTICULARLY CONCERNED WITH CONTROLLING ASPECT RATIOS OF LIGHT BY ADJUSTING ASPECT RATIOS OF VIDEO INFORMATION

摘要

PURPOSE: An illumination unit and a projection-type image display device having the same are provided to control aspect ratios of light radiated to an optical modulator by adjusting aspect ratios of video information in order to increase light use efficiency. CONSTITUTION: An integrator(30) converts light applied from light source(10) to light having uniform light strength. An aspect ratio conversion part feeds light emitted from the integrator which does not corresponds to the aspect ratio of video information back to the integrator, and then emits light with a proper aspect ratio of the video information. The aspect ratio conversion part includes a slit member(40) for controlling an aspect ratio of emission area of the integrator according to the aspect ratio of the video information. The aspect ratio conversion part further includes a recycling member(20) for reflecting light applied again from the slit member to the integrator.