| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a capacity detection circuit which improves an S/N ratio by reducing the influence of a disturbance noise and sufficiently detects a very small capacity value Cs of a crossing part (a sensor element) where a column wired line and a row wired line cross, and a capacity change value ΔCs of the capacity value Cs, and also provide a detection method and a finger print sensor thereof. <P>SOLUTION: The capacity detection circuit, in which the column wired line crosses a plurality of the row wired lines, detects capacity changes at the crossing parts of the column wired line and row wired lines as a voltage value. The capacity detection circuit is provided with; a column wired line driving means which drives the column wired line; a code generation means which generates a code having orthogonality with a time series; a selection synthesis means which selects a plurality of the row wired lines in row wiring based on the code, synthesizes a measured voltage at a crossing part corresponding to the column wired line thus driven, and outputs it as a synthesized measured voltage; and a separation computing means which separates a measured voltage corresponding to the capacity of each crossing part by computing the product sum of the synthesized measured voltage outputted with time series and code. <P>COPYRIGHT: (C)2005,JPO&NCIPI |
