PROJECTION TYPE IMAGE PROJECTION DEVICE

摘要

PROBLEM TO BE SOLVED: To provide a projection type image projection device having a polarization separation means, in which light quantity loss in the polarization separation means can be reduced. SOLUTION: The projection type image projection device 100 spatially modulates linearly polarized illumination light in a reflection type image display element 5 and projects the modulated light as reflection light exhibiting an image. The image projection device 100 includes: a polarization separation element 2 which transmits or reflects illumination light and reflection light reflected by a display surface 5a of the reflection type image display element 5 depending on the polarization direction; and a polarization direction rotating means 4 which is positioned between the polarization separation element 2 and the reflection type image display element 5 and rotates the polarization direction of reciprocally transmitted light by 90°around the optical axis, wherein the direction of bisecting an angle formed between the axial principal ray of the illumination light which is transmitted by a polarization separation surface 2a of the polarization separation element 2 and is made incident on the display surface 5a and the axial principal ray of reflection light reflected by the display surface 5a is caused to substantially match the direction of the optical axis of the polarization direction rotating means 4. COPYRIGHT: (C)2008,JPO&INPIT