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:
Aug. 17, 1993
Filed:
Mar. 20, 1991
Tokio Ishino, Hatsukaichi, JP;
Saburo Sasaki, Tokyo, JP;
Hiroshi Terui, Tokyo, JP;
Akira Ueno, Tokyo, JP;
Ricoh Company, Ltd., Tokyo, JP;
Abstract
A photographing optical system in a varifocal lens is constructed by only a main lens at a wide angle time and a sublens moved backward from the main lens at a telescopic time. A wide angle pattern for prescribing a focusing region at the wide angle time is proximately disposed backward from a focusing starting position at the wide angle time. A telescopic pattern for prescribing a focusing region at the telescopic time is proximately disposed forward from a focusing starting position at the telescopic time. A sliding brush 16 is disposed in a front group frame for holding the main lens and is slidably moved on the wide angle and telescopic patterns to detect the respective focusing regions of the main lens at focal lengths and the focusing starting positions. A focusing position of the lens system is detected by a digital signal generator composed of a rotary encoder rotated in association with the operation of a drive motor.