Patent · US Expired

Circuit arrangement and method for operating a fingerprint sensor

US7239729B2 · kind B2 · utility

0Cited by

7References

4Claims

0Family size

Assignee

Siemens Aktiengesellschaft · DE

Inventors

Stephan Marksteiner · Putzbrunn, DE
Paul-Werner von Basse · Wolfratshausen, DE

Key dates

Filing date	Feb 7, 2001
Grant date	Jul 3, 2007
Priority date	—
Expiry date	Mar 3, 2023

Classification

Technology area (CPC G)Physics
CPC primaryG06V40/1306
WIPO fieldComputer technology
WIPO sectorElectrical engineering

Abstract

A circuit and method are provided for ensuring that a fingerprint sensor is started automatically when a finger is rested thereon such that a sufficiently contrasting image can be produced. A difference between a maximum and a minimum value of the sensor signals is generated wherein, if the difference is sufficiently large, indicating a sufficient contrast of an image to be produced, a normal scanning operation of the fingerprint sensor is initiated, thus ensuring that the complete fingerprint image is produced, a normal scanning operation of the fingerprint sensor is initiated, thus ensuring that the complete fingerprint images produced are of satisfactory quality.

Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.