| 摘要 |
PURPOSE:To decrease windows of the optical system and to reduce the size and cost by interposing a mirror which reflects only light in a specific wavelength range (infrared wavelength range) and transmits light in the other wavelength range in front of a photodetection cell for photometry slantingly to the optical axis. CONSTITUTION:The mirror M which reflects only light in the specific wavelength range (infrared wavelength range) is used for an optical element used for spectral diffusion and interposed in front of the photodetection cell 11-2 for photometry for exposure setting slantingly (about 45 deg.) to the optical axis, and a photodetection cell 8-4 for range finding is arranged on the optical axis of infrared light reflected by the mirror M; and visible light is incident on the photodetection cell 11-2 for photometry and the infrared light is incident on the photodetection cell for range finding. Therefore, only the infrared light for range finding is guided out of the optical axis for photometry and made incident on the photodetection cell for range finding. Consequently, only one window for photodetection is required, and the number of components is decreased to make the outward appearance simple and reduce the size and price more. |
