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:
Jan. 08, 1991
Filed:
Dec. 27, 1989
Keiji Himuro, Tokyo, JP;
Ricoh Company, Ltd., Tokyo, JP;
Abstract
A focal length display device of a camera that comprises a zoom lens unit having a lens group movable on an optical axis driven by a driver. An optical converter having a magnification can be attached to the zoom lens. A detector detects a position of the lens group and outputs a signal of lens position information data which is converted to a digital signal by an A/D converter. A detector circuit detects a state whether the optical converter is attached to the zoom lens unit or not. A focal length calculation circuit calculates the focal length in such a way than, when the detector circuit detects the state in which the optical converter is not attached, the focal length is calculated in response to the lens position, while when the detector circuit detects the state in which the optical converter is attached, the focal length is calculated in response to the lens position and the magnification of the optical converter. The calculated focal length is displayed on a display device.