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:
Oct. 02, 1990
Filed:
Sep. 08, 1989
Yoshimi Ohno, Kawasaki, JP;
Takayuki Hatase, Fukuoka, JP;
Ricoh Company, Ltd., Tokyo, JP;
Abstract
A focus detecting device gathers first image data by a couple of linear arrays of photo diodes in a CCD, which are disposed oppositely with respect to an optical axis of an objective, and second image data by a couple of photo diodes arrayed disposed close to one of the photo diode arrays. A CPU calculates a integer part and fractional part of a displacement of first and second images represented by the first image data, and checks if the calculation results are reliable for focus detection, by using the first and second image data. A counter contained in the CPU counts the number of decisions of unreliable. When a count of counter reaches a preset value and when the latest decision of unreliability is made for the integer part calculation result, a subsequent lens drive is prohibited, and the integration by the CCD, and the integer part calculation are repeated, while presenting a display of 'Unmeasurable'. Further, an additional reliability check is made of the result of the latest integer part calculation. If the additional reliability check shows a satisfactory reliability, the CPU goes out of the repetitive operation of the integration and the integer part calculation, and removes the prohibition of the lens drive.