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. 04, 2000
Filed:
Feb. 09, 1998
Ichiro Fujieda, Tokyo, JP;
Michihisa Suga, Tokyo, JP;
NEC Corporation, Tokyo, JP;
Abstract
An image input device has a optical guide plate exposed to a window of a photo-shield case, a pair of light emitting diodes attached to side surfaces of the optical guide plate for radiating light into it, an area image sensor provided under the optical guide plate, a gradient index lens unit provided between the optical guide plate and the area image sensor and a filter connected to the area image sensor for eliminating a low frequency component from an image carrying signal; when a person presses a finger on the optical guide plate, the fingerprint scatters the light toward the gradient index lens unit, and the area image sensor produces the image carrying signal from the incident light; the reflection on valley lines is gradually varied along the width of the finger, and the elimination of the low frequency component makes the contrast of the image clear.