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:
Nov. 25, 2003
Filed:
Jun. 11, 1996
Kunihiko Yamada, Tanashi, JP;
Canon Kabushiki Kaisha, Tokyo, JP;
Abstract
A focus adjusting apparatus of an optical image formation system performs focus adjustment by: splitting light coming from an object into at least two rays along light paths of different lengths and projecting an image of the object; sensing the split rays and converting them into an image signal; filtering a first signal component out of the image signal and outputting a first value corresponding to an amount of the first signal component; filtering a second signal component, having a frequency different from the first signal component, out of the image signal and outputting a second value corresponding to an amount of the second signal component; judging a focus condition of the projected image by comparing the first value with the second value; and controlling the optical system to adjust the focus condition in accordance with a signal derived from the judging step.