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:
Dec. 12, 1995
Filed:
Nov. 14, 1994
Shinichi Kodama, Tokyo, JP;
Olympus Optical Co., Ltd., Tokyo, JP;
Abstract
In an in-focus sensing device for a camera, an optical system directs the luminous flux from the subject. An optoelectric transducer section converts the optical distribution of the luminous fluxes with different optical path lengths passing through the optical system, into an electrical distribution. A frequency extracting section extracts specific frequency components from each output of the optoelectric transducer section. A frequency component ratio sensing section obtains the ratio of two frequency components with different optical path lengths based on the output of the frequency extracting section. A defocus amount computing section obtains the defocus amount for the optical system based on the frequency component ratio. A driving section drives the optical system based on the defocus amount obtained. A frequency switching section sets a first frequency as the specific frequency at the frequency extracting section, and based on the frequency ratio for the first frequency, sets a second frequency as the specific frequency.