| 摘要 |
PROBLEM TO BE SOLVED: To obtain excellent contrast without changing a polarizing state with a simple arrangement of optical system by arranging a polarized light separation film and a dichronic mirror surface in parallel and arranging a 1/4 wavelength plate. SOLUTION: The polarized light separation part 40 of a polarizing beam splitter(PBS), the dichroic mirrors 41 and 42 and a reflection mirror 43 are arranged, and the 1/4 wavelength plate 44 is arranged in parallel with a ZY surface on an X-axis between the mirrors 42 and 43 so that its phase advance axis is arranged in parallel with Z-axis direction. Light from a light source is made incident nearly from a Y-axis direction and polarized and separated by the separation part 40 to become S polarized light, whose advancing direction is T1. Thereafter, it passes through the mirrors 41 and 42 and the plate 44, is reflected in the direction T2 by the mirror 43, and made incident on the separation part 40 via the plate 44 and the mirror 42 and 41 again to be reflected to the light source side. Since the polarized light component of the light source has only either P or S component, linearly polarized light is kept without using the dichronic film where special phase difference control is applied. |
