System and method for detecting key actuation in a keyboard
US6563434B1 · kind B1 · utility
Assignee
Inventors
Key dates
| Filing date | Nov 12, 1998 |
| Grant date | May 13, 2003 |
| Priority date | — |
| Expiry date | Nov 12, 2018 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH01H2223/052
- WIPO fieldComputer technology
- WIPO sectorElectrical engineering
Abstract
A system and method for detecting key actuation in a keyboard assembly, which in one embodiment, is used as a conductor to electrically communicate with an information appliance. The rows in the keyboard assembly are electrically isolated from one another, and each row contains keys bridging a two-wire bus. Each key has a switch that is closed during key actuation, a diode to polarize the key, and a resistor to provide a resistive load when the switch is closed and the diode is biased with the current flow. Alternatively, each key has a switch that is closed during key actuation, a timer with an output that goes high after a predetermined time period, and a resistor that provides an identifying load when the switch is closed and the output of the timer is high. Other features of the invention include a linear matrix coupled to a row of keys to allow the row to be scanned by sections and individual keys, and a flexible circuit that provides the electrical pathways for the linear matrix.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.