| 摘要 |
An optical fingerprint reader wherein a volume of solid material with a plurality of surfaces defines an illumination path and an imaging path. Light from a source travels along the illumination path, and an image of an object is transmitted by the imaging path. The illumination path is defined by an optical subsystem that includes as one of the plurality of surfaces, a stop at which a focused image of the light source appears. The imaging path is a subset of the illumination path and is defined by a finite conjugate afocal optical subsystem that focuses an image of the object onto a detector. In addition, the stop simultaneously performs dual functions. For the illumination path, the stop becomes a field stop by controlling image illumination. For the imaging path, the stop becomes a field stop by limiting the angular field of illumination for the image of a print at an optical detector. |
