| 摘要 |
PURPOSE:To perform high-precision focus detection and to attain size reduction by arranging optical splitters which have specific spectral characteristics respectively on an optical path and arranging an active type and a photodetection type focus detecting means behind the optical splitters respectively. CONSTITUTION:The reflecting surface 3 of the 1st optical splitter 2 has such spectral characteristics f1 that the reflection factor is low in the visible-light range and high in the infrared-ray rang, and the spectral characteristics f2 of the 2nd optical splitter 6 are reverse. When an object side is bright, luminous flux passed through a photography system 1 is passed through the optical splitters 2 and 6, and then the majority of light in the visible-light range is reflected to form an image on the 1st photodetection surface 8 through the 1st lens 7 for photodetection. This image-forming state is detected and the focus detection is performed. When the object side is dark, a light source 10 operates and its light passed through the splitters 6 and 2 to reflect the majority, which is projected on the object side through the photography system 1; and the reflected light is guided to the surface of the 2nd photodetection part 12 through the 2nd lens 11 for photodetection. The position of the reflected luminous flux is detected to perform focus detection. |
