In-focus detecting device

An in-focus detecting device comprising:

• (A) a photo-electric converter element for converting an image of an object to be photographed formed on the photo-electric converting surface thereof to an electrical output signal;
• (B) detecting means for detecting the degree of focus in each of a plurality of detecting areas set in respective prescribed positions on the photo-electric converting surface of said photo-electric converter element;
• and
• (C) control means arrange to discriminate a relative position of an image forming lens and said photo-electric converter element, on the basis of the degree of focus in each of said detecting areas detected by said detecting means, thereby controlling a direction in which a relative distance between said image forming lens and said photo-electric converter element is to be changed.

An automatic focus detecting device comprising:

• (A) an image pickup element for converting an image of an object to be photographed formed on an image receiving surface thereof through an image forming lens to an electrical output signal;
• (B) driving means arranged to vary a relative position between said image forming lens and said image pick-up element, thereby controlling an image forming position of said image forming lens;
• (C) position detecting means arranged to compare degrees of focus of respective ones of a plurality of detecting areas including a focus detecting area set on said image receiving surface, thereby detecting the relative position between said image forming lens and said image pick-up element, relative to an in-focus position;
• and
• (D) control means arranged to control said driving means on the basis of a result of detection effected by said position detecting means, when the degree of focus at said focus detecting area is lower than a predetermined level, thereby changing the relative position between said image forming lens and said image pickup element in a direction to obtain an in-focus state of the image of the object in said focus detecting area.

A focus detecting device, comprising:

• (A) image pickup means for converting an image of an object to be photographed formed on an image receiving plane into an electrical signal, thereby outputting an image pickup signal;
• (B) detecting means for detecting a degree of focus on each of a plurality of areas set on said image receiving plane, including a central area and its surrounding areas on said image receiving plane, on the basis of said image pickup signal;
• and
• (C) control means for executing arithmetical operations on informations concerning the respective degrees of focus of said central area and its surrounding areas detected by said detecting means and for effecting the focus of control on the basis of the result of the arithmetical operations.

A focus detecting device, comprising:

• (A) image pickup means for converting an image of an object to be photographed formed on an image receiving surface into an electrical signal, thereby outputting an image pickup signal;
• (B) gate means for extracting signals corresponding to a plurality of areas, respectively, set on said image receiving plane, including a central area and its surrounding areas, from said image pickup signal;
• and
• (C) detecting means for detecting a degree of focus at each of said plurality of areas, on the basis of the image pickup signals corresponding to said plurality of areas, respectively, which were extracted by said gate means, said detecting means being arranged to evaluate the respective degrees of focus of said plurality of areas, to detect the de-focus state relative to the object.

A focus detecting device comprising:

• (A) an image pickup means for converting an image of an object to be photographed formed on a photo-electric converting plane to an image signal;
• (B) extracting means for extracting image signals corresponding to a plurality of detecting areas set on said photo-electric converting plane, including a central area and its surrounding areas, from said image signal;
• (C) detecting means for respectively detecting a degree of focus on each of said detecting areas on the basis of the signal extracted by said extracting means;
• and
• (D) deciding means arranged to decide respective degrees of focus os said object to be photographed on said photo-electric converting plane and a background of said object, on the basis of a result of detection effected by said detecting means.