| 摘要 |
<p><P>PROBLEM TO BE SOLVED: To provide a structure of an illumination optical system capable of attaining a function of an optical integrator with a small and simple structure and having high light utilization efficiency and high performance, and to provide a projection display apparatus. <P>SOLUTION: As for the illumination optical system, an optical cavity C2 is constituted of a first reflection mirror 4 for partly reflecting light traveling in a forward direction after being emitted from a lamp 1 and a second reflection mirror 3 for partly reflecting the light traveling in the backward direction after being reflected by the first reflection mirror. A columnar optical element 5 as a body to be illuminated is arranged in an aperture 4 formed in the central part of the first reflection mirror 4 in the optical cavity C2, and a window 13 for transmitting the light traveling in the forward direction is formed in the central part of the second reflection mirror. <P>COPYRIGHT: (C)2004,JPO&NCIPI</p> |
