LIGHT PIPE UNIT AND PROJECTION VIDEO DISPLAY DEVICE USING SAME

摘要

PROBLEM TO BE SOLVED: To provide a projection video display device for improving efficiency of reflection due to recycle of a light flux by improving the shape of a tapered light pipe. SOLUTION: Each of at least two mutually opposite sides of the light pipe has a first face S23a arranged in the incident side of the light pipe and a second face S23b arranged in the outgoing side of the light pipe. The first face S23a and the second face S23b are arranged mutually or by making an angle to an optical axis 100. An angle making the optical axis with the first face is smaller than another angle making the optical axis with the second face. COPYRIGHT: (C)2007,JPO&INPIT