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. 24, 1996
Filed:
Feb. 27, 1996
Takashi Shibaguchi, Yokohama, JP;
Ricoh Company, Ltd., Tokyo, JP;
Abstract
In an optical beam scanning apparatus having an electrooptic lens, a focal point of a light beam is adjusted to be exactly positioned on a scanning surface by a feedback control at any positions scanned by the light beam during a single scanning period. A deviation of a focal position of the light beam relative to the scanning surface is detected, and a detection signal corresponding to the deviation of the focal position is output. A focusing signal is stored and supplied which corresponds to the detection signal obtained when a focal position of the light beam is exactly positioned on the scanning surface. A differential signal is obtained as a difference between the focusing signal and the detection signal. A level of a driving voltage to be supplied to the electrooptic lens is controlled by a driving voltage controlling signal which is a sum of the differential signal and the focusing signal.