| 摘要 |
PROBLEM TO BE SOLVED: To suppress reduction in optical characteristic of a diffraction optical element by reducing harmful light. SOLUTION: In the diffraction optical element 22, of a plurality of diffraction gratings 17', 18', etc., diffraction gratings 18', 19', etc. having groove apexes of a predetermined angle or less include chamfered surfaces 18c', 19c', etc. sloped to slopes 18a', 19a', etc. , which are formed on the lower end side of the inclined surfaces 18a', 19a', etc. COPYRIGHT: (C)2009,JPO&INPIT
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