Focusing arrangement

A detecting circuit for detecting the sharpness of an image formed by an image forming optical system, comprising:

• A. a plurality of micro-photo-conductive elements disposed in a coplanar arrangement forming in a mosaic pattern, said photo-conductive elements respectively emitting an electrical output in response to the intensity of illumination thereof;
• B. a plurality of resistors each having a constant resistance value and individually connected in series with one of said photoconductive elements;
• i. each photo-conductive element and each resistor connected thereto forming a series circuit, said series circuits being connected in parallel with each other;
• C. comparing means for comparing the output of each of said photo-conductive elements, said comparing means being electrically coupled with each juncture between said photo-conductive element and said resistor for comparing the output value of each of said photo-conductive elements so as to give out only the maximum valued output of the photo-conductive element, whereby the sharpness of the object image formed by means of the image forming optical system is detected by virtue of the output emitted from said comparing means.

A detecting circuit for detecting the sharpness of an object image formed by an image forming optical system, comprising:

• A. a plurality of micro photo-conductive elements disposed in a coplanar arrangement forming a mosaic pattern, said photoconductive elements respectively emitting electrical output in response to the intensity of illumination thereof;
• B. a plurality of resistors each having a constant resistance value and individually connected in series with one of said photo-conductive elements;
• i. each photo-conductive element and each resistor connected thereto forming a series circuit, said series circuits being respectively connected in parallel with each other;
• C. comparing means for comparing the output of each of said photo-conductive elements;
• said comparing means being electrically coupled with each juncture between said photo-conductive element and said resistor for comparing the output value of each of said photo-conductive elements so as to give out only the minimum valued output of the photo-conductive element;
• whereby the sharpness of the object image formed by means of the image forming optical system is detected by virtue of the output issued from said comparing means.

A circuit for detecting the sharpness of an object image forming optical system, comprising:

• A. a plurality of micro-sensitive elements having photo-conductive property disposed in a coplanar arrangement forming a mosaic pattern, each of said photosensitive elements being respectively adapted to change an electrically conducting state thereof in response to variations in the intensity of illumination thereof;
• B. means for supplying an electric potential to said photo-sensitive elements, said means being electrically coupled with each of said photo-sensitive elements respectively,
• C. or-gate means having a plurality of input terminal and at least one input terminal, each of said input terminals being individually coupled with each of said photo-sensitive elements;
• D. output means electrically coupled with the output terminal of said gate means for generating an electrical output corresponding to the image sharpness on the basis of the output from said gate means.

A circuit for detecting the sharpness of an object image formed by an image forming optical system, comprising:

• A. a plurality of micro photo-sensitive elements having photo-conductive property disposed in a coplanar arrangement forming a mosaic pattern, each of said photosensitive elements being respectively adapted to change an electrically conducting state thereof in response to variation in the intensity of illumination thereof;
• B. means for supplying an electric potential to said photo-sensitive elements;
• said means being electrically coupled with each of said photo-sensitive elements respectively;
• C. and gate means having a plurality of input terminals and at least one output terminals, said input terminals being coupled individually with each of said photo-sensitive elements;
• D. output means electrically coupled with said gate means at the output terminal, said output means being adapted to generate an electrical output corresponding to the image sharpness on the basis of the output from said gate means.