Parallel encoded piezoelectric keyboard switch and array
US4712092A · kind A · utility
Assignees
Inventors
Key dates
| Filing date | Dec 20, 1983 |
| Grant date | Dec 8, 1987 |
| Priority date | — |
| Expiry date | Dec 20, 2003 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH03K2217/96027
- WIPO fieldBasic communication processes
- WIPO sectorElectrical engineering
Abstract
A keyboard switch includes a plurality of spaced piezoelectric transducers secured to a common strike plate which is selectively impacted to actuate all of the transducers in response to switch actuation. The switch includes a snap action spring member carrying an impact member which impacts the strike plate as the spring member snaps to its actuated state when the switch is depressed . The spring member causes the impact member to maintain a compressive force against the strike plate, maintaining the transducers actuated while the key remains depressed and for a short interval after the key is released. An array of such switches on a keyboard is disposed over a plurality of parallel data lines which electrically contact one or more transducers at each switch in accordance with a switch indentification code. The parallel binary number appearing on the lines is received by processing circuitry which identifies each depressed key by its code. By maintaining compressive forces on the transducers, the system facilitates character processing and generation of certain specialized character functions.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.