摘要 |
The fingerprint sensor device derives an electric output signal in accordance with the topographic relief of a finger under investigation. The sensor incorporates a radiation source, a fingerbed, a first radiation transmitting device, a scanning device, a second radiation transmitting device, and a measuring device responsive to the radiation. The fingerbed has an opening for passing a beam of radiation (light or ultrasound, for instance) from the source therethrough. The scanning device scans this beam of radiation across the finger. Thus, the finger relief is directly scanned by a beam of small impingement spot. The back scattered radiation is directed to the measuring device. Here, the intensity distribution is determined.
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