Proximity sensing device
US5063306A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | May 17, 1990 |
| Grant date | Nov 5, 1991 |
| Priority date | — |
| Expiry date | May 17, 2010 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH03K2217/960775
- WIPO fieldBasic communication processes
- WIPO sectorElectrical engineering
Abstract
A proximity sensing device comprising a sensor including a planar capacitor (1) having a central region (1a) and an outer region (1b) separated by a dielectric area, differentiator means (2,3) associated with said capacitor to form a spiked output pulse from a drive input pulse having at least one stepped edge and comparitor means (10) to repeatedly compare said spiked output pulses with a reference datum indicative of no proximity body being located adjacent to or touching said sensor to determine if such a proximity body is so located. The ration of the perimeters of the central region and dielectric area of the planar capacitor is approximately 2:1 and its capacitance is comparable to that of a human finger.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.