POLARIZATION CONVERSION OPTICAL SYSTEM AND LIQUID CRYSTAL PROJECTION APPARATUS

PROBLEM TO BE SOLVED: To emit luminous flux with uniform polarization directions without expanding a luminous flux diameter even by a simple constitution in a polarization conversion optical system and a liquid crystal projection apparatus. SOLUTION: The polarization conversion optical system includes a light incident part making lighting luminous flux L enter from incident side prism faces 9a and 10a, a light emission part making the incident lighting luminous flux L pass through, a half wavelength plate 11 disposed to cover a first region area S1as a part of the light emission part, and polarization separation faces 10b and 9b separating the lighting luminous flux L incident on the incident side prism faces 9a and 10a into S-polarized luminous flux LS1, P-polarized luminous flux LP1, S-polarized luminous flux LS2, and P-polarized luminous flux LP2, deflecting the S-polarized luminous flux LS2and the P-polarized luminous flux LP1to the direction crossing the optical axis P diagonally, and making S-polarized luminous flux emerged from the first region area S1and P-polarized luminous flux emerged from a second region area S2. The first region area S1and the second region area S2serve as common transmission areas for the separated S-polarized luminous flux and for the separated P-polarized luminous flux. COPYRIGHT: (C)2010,JPO&INPIT