Patent ID: 6640054
Filing Date: 2003-10-28
Classification: G02B,G03B

Abstract:
A focus detecting device for detecting the focus of an objective, comprising:a light receiving sensor having a plurality of photoelectric converters; an optical member movable between a position on a light path at which said optical member routes light, which comes through said objective, to said light receiving sensor, and a position at which said optical member recedes from the path of the light coming through said objective, said optical member having a member for forming a pattern projection in a predetermined field on said light receiving sensor; a focus detection circuit for detecting the focused state of said objective using a light reception signal produced by said light receiving sensor; and a calculation circuit for calculating a correction value, which is used for detecting the focused state of said objective by said focus detection circuit, using a plurality of light reception signals indicating the pattern projection produced by the photoelectric converters located in the predetermined field.