Title:
SENSOR CIRCUIT FOR RECOGNIZING SURFACE SHAPE
Document Type and Number:
Japanese Patent JP3044660
Kind Code:
B2
Abstract:
PROBLEM TO BE SOLVED: To improve the detection accuracy of a sensor circuit for recognizing surface shape.
SOLUTION: A sensor circuit for recognizing surface shape is constituted of a capacitance sensor element 11 the capacitance of which changes in accordance with the surface shape, such as the irregularities, etc., of the fingerprint of a finger, a signal generating circuit 15 which generates the voltage signal corresponding to the capacitance of the element 11, and a detection circuit 20 which detects the voltage signal of a node N1 which is the junction between the element 11 and circuit 15. The signal generating circuit 15 is constituted of a capacitive element 14 having a capacitance value Cs. The first terminal of the element 14 is connected to the node N1 and the voltage at the second terminal of the capacitive element 14 is set at a first potential. After the node N1 is charged with charges, in addition, the charges in the node N1 are extracted by changing the voltage at the second terminal of the capacitive element 14 to a second potential.
More Like This:
| JPS58196403 | CONFIGURATION DETECTING DEVICE |
| JPS56104209 | SHAPE DETECTION |
| JPS5887713 | 【考案の名称】エレベ-タのベルト蛇行検出装置 |
Inventors:
Morimura, Hirotoshi
Shigematsu, Tomoshi
Machida, Katsuyuki
Shigematsu, Tomoshi
Machida, Katsuyuki
Application Number:
JP1999000157763
Publication Date:
March 17, 2000
Filing Date:
June 04, 1999
Export Citation:
Assignee:
NIPPON TELEGR & TELEPH CORP <NTT>
International Classes:
G01B7/28; G06T1/00; (IPC1-7): G01B7/28