RU97118670A - Fingerprint Sensor - Google Patents

Claims (10)

1. A method of reading images from at least a partially heat-conducting surface, preferably a fingerprint reader, according to which a plurality of sensitive elements are brought into thermal contact with a substantial part of the test surface (10) and the temperature of each sensitive element is measured, characterized in that the sensitive the elements (15) are heated by a heat source, the temperature of each sensitive element is measured one or more times, or continuously, the measured temperature (s) or the temperature changes of each sensing element (15) are compared with the heat supplied to measure the heat loss transmitted from the sensing element (15) to the surface (10), and the heat loss in each single sensing element (15) is arranged so as to obtain a segmented image of the surface based on changes in heat loss transmitted from sensitive elements to the surface (10).  2. The method according to p. 1, characterized in that the measurement control and reading of the measurement results is carried out separately for each single sensitive element (15).  3. The method according to claim 1 or 2, characterized in that the heating of each single sensing element (15) is controlled separately, for example, by addressing a local temperature sensor in this element so that it behaves like a heat source.  4. The method according to any one of claims 1 to 3, characterized in that the sensitive element (15) is partially insulated using an insulating material (23) and the thermal conductivity of the insulating material (23) helps smooth out differences in temperature between the sensitive elements (15) so as to provide a filtering effect in a segmented image.  5. A method according to any one of claims 1 to 4, characterized in that the contrast in the segmented image is improved by increasing the amount of heat supplied to the sensor as a whole or to each of the sensitive elements (15) separately.  6. The method according to claim 5, characterized in that the sensitive elements are heated separately, and the heat supplied to each element is controlled in accordance with the temperature or temperature change of the element.  7. A device for reading images from at least a partially heat-conducting surface, preferably for reading fingerprints, comprising a plurality of sensing elements (15) configured to heat contact with a substantial part of said surface (10), and temperature sensors (15) for measuring the temperature of each of the sensors, characterized in that it contains one or more devices (21) for heating said sensing elements and means for generating a signal corresponding to ploprovodnosti for each of the sensitive elements, starting from the known supplied heat and the measured temperature (s) or change (s) temperature, for general segmented image surface on the basis of differences in thermal losses in the sensing elements.  8. The device according to claim 7, characterized in that between the sensitive elements it contains a partially heat-insulating material (23).  9. A device according to any one of claims 7 to 8, characterized in that each sensing element (15) is provided with a separate heat source (21).  10. A device according to any one of claims 7 to 9, characterized in that each sensing element is configured to at least partially control the heat supply.