发明名称 |
Method of determining very small capacitances |
摘要 |
A grid of capacitor surfaces is connected to read lines and control lines. The read lines are connected alternately to the output of a feedback operational amplifier and to a collecting capacitor. The capacitances to be measured are charged repeatedly and the charges are collected on the collecting capacitors. Between the charging operations, the potential on the read lines is kept constant through the use of the low-resistance output of the operational amplifier. The use of this method in the case of a fingerprint sensor makes it possible to evaluate all the read lines together.
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申请公布号 |
US6583632(B2) |
申请公布日期 |
2003.06.24 |
申请号 |
US20010767392 |
申请日期 |
2001.01.23 |
申请人 |
MICRONAS GMBH |
发明人 |
VON BASSE PAUL-WERNER;WILLER JOSEF |
分类号 |
G01B7/28;A61B5/06;G01B7/34;G01R27/26;G06K9/00;G06T1/00;(IPC1-7):G01R27/26 |
主分类号 |
G01B7/28 |
代理机构 |
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代理人 |
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主权项 |
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地址 |
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