Abstract: In one embodiment, a fingerprint sensing system includes a sheet prism having a sensing surface and a number of prismlets positioned opposite to the sensing surface. Each prismlet has an entrance surface and an exit surface, and is adjacent to another prismlet. The width of the sheet is more than ten times the maximum thickness of any one of the prismlets. When a finger is positioned on the sensing surface, a portion of the radiation entering a number of the entrance surfaces and incident at the sensing surface is reflected through total internal reflection. The reflected radiation emits from a number of the exit surfaces to create an image of the fingerprint. In another embodiment, the system further includes a second sheet prism stacked together with the previously described sheet prism. The second sheet prism has a flat surface and a number of prismlets positioned opposite to the flat surface, which faces the prismlets of the previously described sheet prism.

Abstract: A portable, hand-held personal identification device for providing secure access to a host facility includes a biometric sensor system capable of sensing a biometric trait of a user that is unique to the user and providing a biometric signal indicative of the sensed biometric trait. A processing unit responsive to the biometric signal is adapted to compare the biometric signal with stored biometric data representative of the biometric trait of an enrolled person that is unique to the enrolled person, and to provide a verification signal only if the biometric signal corresponds sufficiently to the biometric data to verify that the user is the enrolled person. The verification signal includes information indicative of the enrolled person or the device. A communication unit, including a transmitting circuit, is adapted to transmit the verification signal to a host system.