Focus detecting device having light distribution detection

Details Focus detecting device having light distribution detection Focus detecting device having light distribution detection

1995-06-07

1996-09-24

Allen, Stephone

Radiant energy

Photocells; circuits and apparatus

Photocell controls its own optical systems

354471, 354402, 354409, 250204, G01J 120

Patent

active

055593216

ABSTRACT:
There is disclosed a focus detecting device adapted for use in a camera or the like and provided with; a phototaking optical system for forming an image of the object on a reference plane; a focus detecting optical system for separating, from the light beam passing through the phototaking optical system, at least a pair of light beams passing through spatially different areas on a first predetermined plane axially spaced by a first distance from the reference plane, thereby forming images of the object; a photoelectric converting device composed of plural photosensor elements and adapted to generate object image signals corresponding to the intensity distribution of the object images formed by the focus detecting optical system; a phototaking optical system information device for generating information on the shape of exit pupil at fully-open diaphragm of the phototaking optical system and on a second distance from the reference plane to the exit pupil; a focus detecting optical system information device for generating information on the form of the areas on the first predetermined plane and on the first distance; a light amount distribution detecting device for determining the decrease in light amount on the plane of photosensor elements of the photoelectric converting device as light amount information relating to the position on the plane of photosensor elements, encountered when the phototaking optical system and the focus detecting optical system are combined, based on the information from the phototaking optical system information device and from the focus detecting optical system information device; and a focus detection calculation device for effecting a process on the object image signals based on the light amount distribution information, thereby determining the defocus amount of the current object image plane relative to the reference plane.

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patent: 5235380 (1993-08-01), Yamada et al.
Patent Abstracts of Japan, vol. 7, No. 78 (P-188), 31 Mar. 1983.
Patent Abstracts of Japan, vol. 8, No. 171 (P-293), 8 Aug. 1984.

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