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:
Mar. 13, 1990
Filed:
Jun. 19, 1989
Toshihiko Karasaki, Osaka, JP;
Kazumi Sugitani, Osaka, JP;
Minolta Camera Kabushiki Kaisha, Osaka, JP;
Abstract
A focus detecting optical system is disclosed which includes an objective lens for forming an image of an object, a plurality of focus detecting blocks, and a focus condition calculating device for calculating a focus condition of the objective lens in accordance with the light intensity distribution signals produced by the plurality of the focus detecting blocks. Each of the focus detecting blocks includes a condenser lens located nearby a predetermined focal plane of the objective lens, a pair of image re-forming lenses located behind the condenser lens for reforming a pair of secondary images of the image formed by the objective lens, a mask plate having a pair of apertures through which light fluxes forming the secondary images pass and a light receiving unit for receiving the pair of the secondary images formed by the pair of image re-forming lenses to produce a light intensity distribution signal representative of the light intensity distribution of the secondary images. The apertures in the mask plate of at least one specified focus detecting block has a configuration different from that of the other focus detecting blocks.