| 摘要 |
PURPOSE:To detect the focusing positions of optical images by detecting and comparing the sharpness of optical images which are formed by two-split pieces of luminous flux about a direction parallel to photodetector arrays through groups of the photodetector arrays. CONSTITUTION:Lenses 11 and 12 separate pieces 6AL and 6BL of luminous flux corresponding to the left half part of an optical image formed on their iris surfaces through an image-forming lens 1 and pieces 7AL and 7BL corresponding to the right half part from each other, and they are detected by photodetector arrays 6A and 6B, and 7A and 7B; those lenses have columnar curved surfaces at right angles to the paper surface and the photodetector arrats are provided at right angles to the paper surface. Further, a correcting means 20 consisting of a lens with asymmetry of rotation is provided between the image-forming lens 1 and lenses 11 and 12, and a phase plate 14 for giving photodetector array groups 6 (6A and 6B) and 7 (7A and 7B) some specific optical difference is arranged to obtain pieces of optical image information by both lenses 11 and 12 on the same plane. |
