Transducer for fingerprints and apparatus for analyzing fingerprints
First Claim
1. In an apparatus for the identification of fingerprints having a fingerprint sensing member with a sensing surface and means for interrogating the sensing surface with a light beam, whereby the light beam is modulated in accordance with the structure of the fingerprint, the improvement comprisingthe sensing surface having a random surface roughness and being made of a material having a softening temperature greater than ambient temperature and close to human body temperature such that when a finger is placed onto the sensing surface, portions of the material will soften to disturb the random surface roughness in accordance with the geometrical structure of the print of the finger, the roughness of disturbed portions of the sensing surface serving to scatter light differently from the roughness of the undisturbed portions.
0 Assignments
0 Petitions
Accused Products
Abstract
The fingerprint transducer contains a sensing member having a sensing surface for receiving a fingerprint. The sensing member is made of a material which has a transition or softening temperature that is higher than ambient temperature and close to the temperature of the finger. Particularly, the softening temperature is chosen such that the material of the sensing member will start to melt on the surface when the finger is pressed against the sensing surface. The sensing surface has a surface relief of random roughness. In other words, the sensing surface has variations in elevation which do not show a specific pattern. The method for analyzing fingerprints comprises the steps of generating a surface relief of random space on a sensing surface of a sensing member, generating the fingerprint on the sensing surface by pressing a finger thereto, and optically reading the fingerprint from the sensing surface.
-
Citations
7 Claims
-
1. In an apparatus for the identification of fingerprints having a fingerprint sensing member with a sensing surface and means for interrogating the sensing surface with a light beam, whereby the light beam is modulated in accordance with the structure of the fingerprint, the improvement comprising
the sensing surface having a random surface roughness and being made of a material having a softening temperature greater than ambient temperature and close to human body temperature such that when a finger is placed onto the sensing surface, portions of the material will soften to disturb the random surface roughness in accordance with the geometrical structure of the print of the finger, the roughness of disturbed portions of the sensing surface serving to scatter light differently from the roughness of the undisturbed portions.
Specification