| 摘要 |
PROBLEM TO BE SOLVED: To provide a color separation optical system that can more effectively reduce ghost occurring due to reflection at an air interface between two prisms than in the conventional manner. SOLUTION: The color separation optical system has such a configuration as to extract blue light, red light and green light respectively with a first prism 10, a second prism 20 and a third prism 30, wherein the surface 12 on which a blue light reflection dichroic film DB2 on the first prism 10 is formed and an incident surface 21 on the second prism 20 are arranged with an air interval 10AG so as to face each other. An antireflection film AR2 for interface antireflection for reducing reflection of light of specific wavelength region transmitted by the blue light reflection dichroic film DB2 is formed on the incident surface 21 of the second prism 20. The antireflection film AR2 for interface antireflection has such a characteristic as to reduce reflection of light in the wavelength region of at least 500 nm to 550 nm, as the light of specific wavelength region. COPYRIGHT: (C)2009,JPO&INPIT
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