| US 7,576,843 B2 | ||
| Optical device for biometric capture by contact and system using said device | ||
| Matthieu Rouget, Maisons Laffitte (France); Laurent Lambert, Paris (France); and Jean-Christophe Fondeur, Levallois (France) | ||
| Assigned to Sagem Securite, Paris (France) | ||
| Appl. No. 11/571,095 PCT Filed Jun. 22, 2005, PCT No. PCT/FR2005/001578 § 371(c)(1), (2), (4) Date Dec. 21, 2006, PCT Pub. No. WO2006/008396, PCT Pub. Date Jan. 26, 2006. |
||
| Claims priority of application No. 04 06843 (FR), filed on Jun. 23, 2004. | ||
| Prior Publication US 2008/0062402 A1, Mar. 13, 2008 | ||
| Int. Cl. G06K 9/74 (2006.01) | ||
| U.S. Cl. 356—71 | 10 Claims |
| 1. An optical device for biometric sensing by contact, the device comprising:
an optical element having a face that constitutes at least in part a surface for apposition of a body part from which it is
desired to sense a biometric characteristic;
an electromagnetic radiation source associated with said optical element to illuminate said face through the optical element
with electromagnetic radiation substantially perpendicular to said face; and
sensor means suitable for picking up reflected radiation coming from said face of the optical element;
wherein said face of the optical element is coated with a thin layer defining a predetermined repeating pattern and made of
a material such that, in relation with the material constituting the optical element, said thin layer defining said predetermined
pattern is transparent to the electromagnetic radiation emitted by the radiation source when a body part is placed on said
face of the optical element and is significantly less transparent for an interfering external electromagnetic radiation that
is inclined relative to said face of the optical element and without any body part being apposed on said surface of the optical
element,
whereby the image received by the sensor means can be discriminated as to whether it constitutes a real image or a latent
image.
|