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:
Sep. 15, 1998
Filed:
Jun. 11, 1997
Hamamatsu Photonics K.K., Shizuoka-ken, JP;
Abstract
A tapered FOB (20) obtained by forming optical absorbers on the outer surfaces of fibers and bundling these fibers is joined to a slant FOB (10) obtained by bundling fibers, and a CCD (60) is arranged at the output end face of the tapered FOB (20). The slant angle (.beta..sub.0) of a detection surface (11) of the slant FOB (10) on which a fingertip is to be placed is set to an angle at which background light incident from air on the slant FOB (10) is not reflected as total internal reflection at the interface between the core and cladding of the slant FOB (10). The slant angle (.beta..sub.1) of the tapered FOB (20) is set such that background light reaching the tapered FOB (20) becomes incident at the interface between the core and the cladding at an angle smaller than the critical angle at which total internal reflection occurs. Unwanted background light and illumination light are eliminated, and the S/N ratio of a fingerprint image to be detected can be increased.