Patent ID: 6556935
Filing Date: 2003-04-29
Classification: G06K

Abstract:
A small shape recognizing capacitive sensor device comprising:a number of detection elements arranged adjacent to each other; a number of sensor circuits connected to said detection elements, respectively; and a correction circuit for correcting an output signal level of said sensor circuit, said output signal level correction circuit comprising a calibration circuit connected to an output side of said sensor circuit, a calibration reference signal generation circuit for generating a calibration reference signal, and a comparison circuit for comparing an output from said sensor circuit with the calibration reference signal and supplying a difference output to said calibration circuit as a control signal, wherein said calibration circuit corrects a level of a sensor circuit output on the basis of the control signal such that the difference between the output from said sensor circuit and the calibration reference signal becomes zero, and wherein said sensor circuit comprises a sensor circuit with voltage-time conversion function for converting an output signal corresponding to an electric charge amount from said corresponding detection element into a signal which changes in a direction of time axis, and said comparison circuit compares a voltage-time conversion signal as the output from said sensor circuit with the calibration reference signal and outputs a difference signal to said calibration circuit as the control signal.