Finger identification
US4322163A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Nov 17, 1980 |
| Grant date | Mar 30, 1982 |
| Priority date | — |
| Expiry date | Nov 17, 2000 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG06V40/1335
- WIPO fieldComputer technology
- WIPO sectorElectrical engineering
Abstract
A finger pressed against a platen provides a fingerprint object which is scanned by an interrogating beam of collimated light in the form of a slit and that is linearly displaced across the platen. As the slit-beam scans across the back surface of the platen, the reflected light beam is modulated. The modulated beam is imaged onto a linear array of photodiodes to provide a series of output signals indicative of modulation information. The outputs of the diodes are serially interrogated at each of successive scan positions to provide a set of signals containing fingerprint information. The platen has a transparent glass base. A layer of transparent, compressible, resilient epoxy is on the back of the glass base. The epoxy layer has a flat back surface. A thin silver reflecting layer on the back surface of the epoxy provides a flat mirrored surface to reflect the light beam. A further epoxy layer on top of the silver provides mechanical filtering. A lacquer layer at the back protects the platen from wear. When a finger is applied to the back surface, the ridges of the finger distort the underlying layers sufficiently so that the reflected light at the ridge zones is scattered while t…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.