US 6,640,054 B2 · Focus detecting device

Abstract

Disclosed is a focus detecting device consisting mainly of a light receiving sensor, a reflecting mirror, a first detection circuit, and a focus detection circuit. The light receiving sensor has a plurality of photoelectric converters. The reflecting mirror is movable between a first position at which the reflecting mirror reflects light that comes from an objective, and routes the light to the light receiving sensor, and a second position at which the reflecting mirror recedes from the path of the light coming from the objective. The reflecting mirror has a member that helps form light distributions in a predetermined field on the light receiving sensor. Moreover, the reflecting mirror makes a return from the first position to the second position or vice versa. The first detection circuit detects a change in the light distributions formed in the predetermined field on the light receiving sensor which is observed between before and after the reflecting mirror makes a return. The focus detection circuit detects the focused state of the objective using a light reception signal produced in a field other than the predetermined field on the light receiving sensor and a detection value produced by the first detection circuit. Herein, the focus detecting device is incorporated in a camera.

Claims20

Dependent claims

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.

2 more elements

A focus detecting device for detecting the focus of an objective, comprising:

a light receiving sensor having a plurality of photoelectric converters;
a reflecting mirror movable between a first position at which said reflecting mirror reflects light that comes through said objective, and routes the light to said light receiving sensor, and a second position at which said reflecting mirror recedes from the path of the light coming through said objective, said reflecting mirror having a member for forming a pattern projection in a predetermined field on said light receiving sensor when lying at said first position, and said reflecting mirror making a return from said first position to said second position or vice versa;
a first detection circuit for detecting a change in the pattern projection formed in said predetermined field on said light receiving sensor which is observed between before and after said reflecting mirror makes a return;
a focus detection circuit for detecting the focused state of said objective by using a light reception signal produced in a field other than the predetermined field on said light receiving sensor and a detection value corresponding of the change detected by said first detection circuit.

1 more element

Dependencies are inferred from the claim text.

Focus detecting device

Life of this patent

Focus detecting device

Life of this patent

Abstract

Claims20