| 摘要 |
PROBLEM TO BE SOLVED: To obtain good polarizing reflection characteristics in a wide wavelength range even when the incident angle of a beam is changed, by dividing the reflection surface into plural regions and forming each region to have different film characteristics from others. SOLUTION: The reflection surface 1 of a substrate 2 where silver is vapor deposited is divided into two regions, and two different protective films 1a, 1b are formed by vapor deposition. The protective film 1a is a MgF2 film having 70nm thickness, while the protective film 1b is a SiO2 film having 180nm thickness, and these films are formed on a respective half of a same silver vapor deposition film. A light beam from a body S enters the reflection surface 1 of the substrate 1 and each 50% of the beam is reflected by the respective protective film 1a, 1b having different polarizing reflection characteristics. The reflected beam enters an imaging lens 4 to form an image on the imaging plane 5 of an imaging element. Therefore, by the reflection on the protective films 1a, 1b having different characteristics from each other, the polarization reflection characteristics can be maintained good in a wide wavelength range including a short wavelength region even when the incident angle is changed. As a whole, high reflectance characteristics can be obtd.
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