Capacitive keyboard switch
US4466046A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Apr 6, 1983 |
| Grant date | Aug 14, 1984 |
| Priority date | — |
| Expiry date | Apr 6, 2003 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH03K17/972
- WIPO fieldBasic communication processes
- WIPO sectorElectrical engineering
Abstract
A capacitive switch employs a conical conducting spring disposed within a switch housing in spaced relation to an underlying capacitive plate which is covered by a dielectric layer. The bottom coil of the spring engages slots of the housing so that the spring is held above the capacitive plate. A substantially zero capacitance is defined when the switch is in its rest state with the spring biasing a switch pushbutton upwardly. When the pushbutton is pressed, the spring is compressed against the underlying capacitive plate. The compressed coils of the spring define a predefined capacitance which indicates the depressed condition of the switch.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.