| 摘要 |
PURPOSE:To improve the accuracy of focus detection by using prism arrays having a minute critical angle for the pupil splitting means of an imaging optical system and detecting the transverse deviation of the images on the intended imaging plane which arises with the deviation in the focus of the imaging optical system. CONSTITUTION:Two prism arrays 6A and 6B having a minute critical angle have the same construction but have the reflection surfaces of the critical angle which incline in opposite directions; therefore, the split pupil images of an imaging optical system are projected on the respective photodetector arrays 7A, 7B disposed on the intended imaging plane of said imaging optical system and the directions of the transverse deviation of said images are opposite in direction. Since the arrays 7A, 7B arranged on a substrate 11 permit the substantial reduction in the pitch between the photodetectors, the output distribution signals corresponding to the respective split pupil images of the imaging optical system obtained from the arrays 7A, 7B are obtained with high accuracy. |
