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: An optical system of an endoscope for investigation and observation of spaces in medicine and engineering. The construction permits the panoramic observation of the internal surface of the space or channel. The endoscope contains a tube in which a lens is installed along the axis of symmetry and coaxial along the entire internal surface of the tube a longitudinal fiber illumination light guide is installed. A lateral observation nozzle is installed on the tube with the possibility of unlimited rotation around the tube. The nozzle is provided with a unit of two reflection prisms, one is meant for lateral observation and the other for lateral illumination. The lateral observation prism is incorporated into the body of the lateral illumination prism. A diaphragm overlapping the face of the lateral observation prism presented to the lens is arranged, on the nozzle.

Abstract: A thin, inexpensive, removable platen for a direct fingerprint reader without a permanently attached platen. A removable platen is formed as a transparent area on a credit card, passport or identification card or as a separate card. The portable platen on the card is inserted over an imaging area of the direct fingerprint reader. Light from the direct fingerprint reader passes through an optical surface formed on the underside of the portable platen, is reflected off the fingerprint and passes back through the optical surface to the imaging apparatus where the image is digitized and analyzed. The optical surface is formed such that the incident light is not refracted away from the fingerprint and the reflected light from the fingerprint is not refracted away from the imaging apparatus.

Abstract: A thin, inexpensive, removable platen for a direct fingerprint reader without a permanently attached platen. A removable platen is formed as a transparent area on a credit card, passport or identification card or as a separate card. The portable platen on the card is inserted over an imaging area of the direct fingerprint reader. Light from the direct fingerprint reader passes through an optical surface formed on the underside of the portable platen, is reflected off the fingerprint and passes back through the optical surface to the imaging apparatus where the image is digitized and analyzed. The optical surface is formed such that the incident light is not refracted away from the fingerprint and the reflected light from the fingerprint is not refracted away from the imaging apparatus.