| 摘要 |
PURPOSE:To provide the detector of a small size and good detection sensitivity by providing the focusing detecting lens having a rectangular opening and a plurality of photodetectors in series. CONSTITUTION:A focusing detecting lens 3 is provided in tandem with a photographing lens 2. This lens 3 is let to have an opening of nearly square form by parallel cutting out the central part of a circular lens. The object image is projected to a photodetector 5 by way of an optical pat adjusting member 4 by the lens 3. The photodetector 5 comprises arraying plural photodiodes or the like in array form. The focusing signal is obtained by this detector 5 through the utilization of the fact that the sharpness of the image becomes largest in the focusing position. Since the photodetectors constituting the photodetector 5 is so disposed that their configuration direction becomes parallel with the lengthwise direction of the lens 3, the signal obtained in the photodetector 5 is similar to that in the case of a circular lens and since the depth of focus of the lens 3 is shallower than that of the circular lens, the detection sensitivity of the focus detector may be enhanced. |
