초록 ▼

A focus detecting device which performs focus detection in such a manner that an image of an object formed through an image forming lens is received by an array of many electric charge storing type photo-sensors and, under such a condition, the image is electrically scanned by extracting, in a time

A focus detecting device which performs focus detection in such a manner that an image of an object formed through an image forming lens is received by an array of many electric charge storing type photo-sensors and, under such a condition, the image is electrically scanned by extracting, in a time serial manner, the output of each photo-sensor, and then the sharpness of the image is detected from a scanning output thus obtained; or that two images of the object which are formed through a range-finding optical system with an apparent parallax corresponding to distance to the object are received by different arrays of such photo-sensors respectively and, under such a condition, the two images are electrically scanned separately from each other by extracting, in a time serial manner, the output of each of the photo-sensors and scanning outputs thus obtained are compared with each other to detect the relative parallax of the two images. In this device, for making the scanning output of the photo-sensor array or arrays always correct irrespective of variation in the brightness of the object, the scanning recycle time duration of the photo-sensor array or arrays is automatically adjusted according to the brightness of the object; and, accordingly, the electric charge storing time of each photo-sensor in the photo-sensor array or arrays are automatically adjusted thereby.

대표청구항 ▼

A focus detecting device for detecting the focusing of an image forming optical system on an object, said optical system having an optical axis and being adjustable along the axis so as to form an image of the object on a predetermined focusing plane, said device comprising: (A) photo-sensor array m

A focus detecting device for detecting the focusing of an image forming optical system on an object, said optical system having an optical axis and being adjustable along the axis so as to form an image of the object on a predetermined focusing plane, said device comprising: (A) photo-sensor array means having a plurality of electric charge storing type photo-sensor elements, said array means being disposed at a position substantially corresponding to said focusing plane; (B) driver circuit means for electrically driving said photo-sensor array means, said driver circuit means being electrically coupled to the array means to provide the array means with intermittent start pulses at cyclical intervals and intermittent scanning pulses and for causing the array means to produce, one after another in time series, outputs of electric charge stored in each photo-sensor element during a period of time corresponding to the cyclical interval of said start pulses; the electric charge being stored in each photo-sensor element corresponding to the brightness of the portion of the image appearing at the photo-sensor element within said period of time; (C) signal processing circuit means for processing the output signal of said photo-sensor array means, said processing circuit means being electrically coupled to the array means to provide an electrical output representative of the focusing condition of the optical system relative to the object, on the basis of said output signals of the array means; (D) control circuit means for adjusting the scanning recycle time duration in correspondence to the brightness of the object, said control circuit being electrically coupled to said driver circuit means to accomplish the adjustment of the scanning recycle time duration by adjusting the cyclical interval of said start pulses to be applied to said array means in correspondence to the brightness of the object; and (E) said control circuit means including means for detecting the brightness of at least a portion of the image appearing at the photo-sensor array means within a period of time, means for establishing a range of reference values and control means for adjusting the scanning recycle time duration in response to said detecting means detecting that the instantaneous brightness of at least a portion of the image appearing at the photo-sensor array means deviates from the predetermined range of reference values.