Touch sensor identifying a body part
US6545614B1 · kind B1 · utility
Assignee
Inventor
Key dates
| Filing date | Sep 28, 1999 |
| Grant date | Apr 8, 2003 |
| Priority date | — |
| Expiry date | Sep 28, 2019 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH03K17/94
- WIPO fieldBasic communication processes
- WIPO sectorElectrical engineering
Abstract
A touch sensor which is able to detect the touch of a finger with reasonable accuracy. In this touch sensor, the oscillator unit supplies a high-frequency signal to the electrode unit. If the item detected is a biological entity of a human body such as a finger, the impedance of the electrode unit will change. The impedance is initially matched to that on the input side of the electrode when the finger is in touch with the electrodes. The reflected wave will be smaller because of the matching of impedance when the finger is in touch with the electrode. By detecting this reflected wave and comparing it with a reference signal in the discriminator unit, it can be determined that the reflection level is lower and so a conclusion can be made that the electrode is touched by a person.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.