Keyboard key discrimination based on time division multiplexing
US6621484B1 · kind B1 · utility
Assignee
Inventor
Key dates
| Filing date | Jun 27, 2000 |
| Grant date | Sep 16, 2003 |
| Priority date | — |
| Expiry date | Jan 17, 2021 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH03M11/20
- WIPO fieldBasic communication processes
- WIPO sectorElectrical engineering
Abstract
A keyboard switch matrix arrangement provides keyboard key discrimination utilizing simultaneous groupings of drive line combinations and sense line combinations (time division multiplexing) to discriminate between keyboard keys with substantially fewer total drive and sense lines than a conventional switch matrix, thereby substantially reducing the number of required IC pin connections. The invention permits given sense lines to sense more than one drive line for a valid key press duration (i.e., key actuation), and given drive lines to drive more than one sense line for a given valid key press duration. In this manner, and through utilization of time division multiplexing, the switch capacity of a matrix with a given number of drive lines and sense lines can be substantially increased.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.