| 摘要 |
PROBLEM TO BE SOLVED: To provide a focus detecting device for making enlargement of an arrangement region of a focus detecting area and lowering of the degree of manufacturing difficulty compatible. SOLUTION: The focus detecting device includes a main mirror for introducing to a finder optical system by reflecting a field light flux through a photographing lens and transmitting a partial light flux, a sub-mirror for reflecting a transmission light flux of the main mirror on a rear face side of the main mirror, and a focus detecting part for detecting a focus of the photographing lens on the basis of the reflection light flux of the sub-mirror. The sub-mirror is provided with a volume reflection hologram reflecting a paraxial light beam of the photographing lens at a larger reflection angle than an incident angle out of the light flux transmitting the main mirror. COPYRIGHT: (C)2006,JPO&NCIPI |
