| 摘要 |
PURPOSE:To elevate productivity, by laminating a polarized film on a wavelength plate, opposing a light source to the polarized film, providing an optical axis of the wavelength plate and an optical path at a specified angle, and forming the wavelength plate and a polarized beam splitter as one body. CONSTITUTION:Against an optical path of light emitted from a light source 1, a 1/4 wavelength plate 9 on which a polarized film 8 has been laminated is placed at an angle by which an optical axis C becomes theta(0<theta<90 deg.). Even when the light source 1 is a semiconductor and the oscillation wavelength is varied, adjustment can be made so that return light to the light source becomes minimum by only adjusting the angle theta. The polarized film 8 is obtained, for instance, by alternately laminating scores of layers of dielectrics whose refractive indexes are different, such as SiO2, TiO2, etc. When incident light is P polarized light, it becomes circular polarized light by the wavelength plate 9, and a reflected ray from a target 6 becomes circular polarized light of a reverse rotation, becomes S polarized light by the wavelength plate 9, and is reflected by the polarized film 8. In order to obstruct a little P component which travels straight, a 1/2 wavelength plate 10 can be laminated. |
