Ambient light rejection filter
US8077929B2 · kind B2 · utility
12Cited by
29References
13Claims
0Family size
Assignee
Inventor
Key dates
| Filing date | Feb 21, 2007 |
| Grant date | Dec 13, 2011 |
| Priority date | — |
| Expiry date | Feb 4, 2030 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG06V40/1324
- WIPO fieldComputer technology
- WIPO sectorElectrical engineering
Abstract
A fingerprint reader is described. The fingerprint reader includes an illumination source that produces light and a camera. An optical window is also part of the reader. The window is positioned so that light from the illumination source passes through the optical window and then is reflected to the camera for imaging a person's fingerprint. A filter may be positioned on or proximate to the optical window. The filter prevents ambient light from reaching the camera. In some situations, the filter will be a dielectric mirror, a dielectric filter, a holographic mirror, a holographic filter, a dichroic mirror or a dichroic filter.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.