| 摘要 |
PROBLEM TO BE SOLVED: To realize a polarization converting optical system with effectively high light usage efficiency, and for eliminating effects of return light with respect to a light source. SOLUTION: The polarization converting optical system 10 converting a polarization state of incoming beams into a linearly polarized beam in one direction includes an inorganic polarization separating element 15 formed with a fine periodic structure by inorganic material is formed on at least one face of a parallel flat transparent substrate, transmitting a P polarization component LP of the incoming beams LO, and reflecting an S polarization component LS, and a reflection optical element 17 comprised by combining a flat reflecting face 171A and a 1/4 wavelength layer 172, reflecting the polarization component LS, and converting it into a polarization state LP1 the same as the polarization component LP. An incidence angleθof a principal ray of the incoming beams LO into an incidence side face of the inorganic polarization separating element is set at an angle within a range of≥1°and≤12°, and a relative physical relationship of the inorganic polarization separating element 15 and the reflection optical element 17 is set such that the light beams LP and LP1 become mutually parallel light beams. COPYRIGHT: (C)2009,JPO&INPIT |
