JPS57158814A - Focusing detector - Google Patents

Abstract

PURPOSE:To prevent the generation of an erroneous focus signal, by referring to the movement direction signal of a focusing optical system to discriminate the magnitude of the appreciation function value for every photodetector array which is obtained on the basis of the output signal from the photodetector array. CONSTITUTION:A part of an object is projected through a half mirror 61 and a reflective mirror 62 simultaneously by a focusing optical system 3. Output of photoelectric transducers of photodetector arrays 6 and 6' are converted to digital signals by an A/D converter 63 and are stored temporarity in a memory 64 and are read out successively by the signal from a control circuit 65 with the distinction between photodetector arrays 6 and 6' and are applied to an operating circuit 66. In the operating circuit 66, output signals of photoelectric transducer are used to calculate an appreciation function value in accordance with a prescribed appreciation function. The operation result is led from the operating circuit 66 to a comparing circuit 69, and the comparison output is inputted to a discriminating circuit 71 to obtain a display signal corresponding to the focusing state, and this signal is led to the control circuit 65, and a control signal is supplied to a display element driving circuit 72, and one of display elements 73-76, which corresponds to the focusing state, such as an element for the front focus, the rear focus focusing, or the like is lit optionally.