| 摘要 |
PROBLEM TO BE SOLVED: To provide an inexpensive polarizing separation and conversion element which can separate and convert polarized light with high accuracy. SOLUTION: The element satisfies the relation of t2/t1=4sin<2> x-1, wherein t1 is the distance (thickness of a transparent substrate 113a) between a polarizing separation film 111 and a reflecting film 112 in a polarizing separation part 110, t2 is the distance (thickness of a transparent substrate 113b) between the polarizing separation film 111 in the polarizing separation part 110 and the reflecting film 112 in the adjacent polarizing separation part or between the reflecting film 112 in the polarizing separation part 110 and the polarizing separation film 111 in the adjacent polarizing separation part, and x ( deg.) is the incident angle to the polarizing separation film (45 deg.<x<90 deg.). The element holds regions 110a and 110b where no film is formed on the transparent substrates so as to keep the optical path. The length w1 of the region where the film is formed in the polarizing separation part 110 and the length w2 of the region where the film is not formed are controlled to satisfy w2/w1=0.5-1/2tan<2> x.
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