| 摘要 |
PROBLEM TO BE SOLVED: To improve the video output efficiency of an optical system which constitutes a reflection type liquid-crystal projector with a simple optical constitution. SOLUTION: A dichroic mirror 3 separates B illumination light from G illumination light and R illumination light in the illumination light composed of p- polarized light from a light source part, and the B illumination light is passed through a polarizing surface 4a of a 1st PBS4 and reflected to B-LCD7B to obtain s-polarized light. An optical retardation plate 5 rotates the plane of polarization of the G illumination light between the G illumination light and R illumination light reflected at the dichroic mirror 3 by 90 deg. and passes it as s-polarized light, and passes the R illumination light as p-polarized light as it is without rotating the plane of polarization of the R illumination light; and a 2nd PBS6 reflects the G illumination light, passes the R illumination light, and reflects them to G-LCD7G and R-LCD7R respectively. Consequently, B image light is s-polarized light, G image light is p-polarized light, and R image light is s-polarized light; and a dichroic prism 8 which puts those three colors together reflects the B image light and passes the G image light and R image light. |
