The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Feb. 12, 1991
Filed:
May. 06, 1988
Toshihiko Karasaki, Osaka, JP;
Kazumi Sugitani, Osaka, JP;
Minolta Camera Kabushiki Kaisha, Osaka, JP;
Abstract
A focus detecting device which comprises an objective lens for forming an image of an object, a condenser lens, located behind a predetermined focal plane of the objective lens, for converging the light passed through the objective lens, a pair of image re-forming lenses, located behind the condenser lens, for re-forming a pair of secondary images of the image formed by the objective lens on an off-axial region of the objective lens located at a position far from the optical axis thereof, a light direction changing device, located nearby the condenser lens, for changing the direction along which light bundles forming the secondary images passes towards the optical axis, and a light receiving device for receiving the pair of the secondary images formed by the secondary image forming means to produce a light intensity distribution signal representing the light intensity distribution of the secondary images, a focus condition calculating device for calculating a focus condition of the objective lens by means of detecting the positions of the pair of the secondary images in accordance with the light intensity distribution signal.