Key rollover keyboard (patent 3918051)
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| Country | US |
|---|---|
| Patent number | 3918051 |
| Issued on | 10 June 1974 |
| Inventor | Victor M. Bernin |
| Reference | US3918051 |
Key rollover keyboard (patent 3918051) is an n-key rollover type keyboard that comprises a two dimensional switching matrix with a plurality of drive wires and sense wires pulsed and scanned by a drive and multiplexer circuits respectively with a hysteresis feedback loop. Each key switch has a location that depends on the assigned code to the particular key switch. The output of the shift register is compared with the output of the amplifier so that a strobe generated signal is only applied to the depressed key. [1]
Contents
Description
Key rollover keyboard
- Inventor: Victor M. Bernin
- Patent number: 3918051
- Filing date: 10 June 1974
- Issue date: 25 January 1975
Referenced by
- US patent 3978474, Keith Allen Engstrom, "Keyboard with n-key lockout and two key rollover protection", issued 31 August 1976, assigned to Illinois Tool Works Inc.
- US patent 4024534, Wilbur E. DuVall, "Keyboard encoding with repeat key pause", issued 17 May 1977, assigned to Xerox Corporation
- US patent 4037225, Wilbur E. DuVall, "Keyboard encoding system with electronic hysteresis", issued 19 July 1977, assigned to Xerox Corporation
- US patent 4110748, Francis C. Marino, "Keyswitch with hysteresis", issued 29 August 1978, assigned to Burroughs Corporation
- US patent 4300127, Victor M. Bernin, "Solid state noncontacting keyboard employing a differential transformer element", issued 10 November 1981
- US patent 4390866, Keith A. Engstrom, "Keyboard with electronic hysteresis", issued 28 June 1983, assigned to Illinois Tool Works Inc.
- US patent 4494109, Victor M. Bernin, "Noncontacting keyboard employing a transformer element", issued 15 January 1985
- US patent 4538146, Dennis E. Morris, "Integrated circuit output pins used for input signals", issued 27 August 1985, assigned to National Semiconductor Corporation
- US patent 4581603, William E. Ingold, "Switch matrix key closure validation device and method", issued 8 April 1986, assigned to The Maxi-Switch Company
- US patent 4794601, Keith A. Engstrom, "Keyboard data entry system with hysteresis", issued 3 November 1987, assigned to Illinois Tool Works, Inc.
- US patent 4706068, Martin F. Eberhard, "Four wire keyboard interface", issued 20 September 1988, assigned to Wyse Technology, Inc
- US patent 4772874, Hiroshi Hasegawa, "Keyboard apparatus", issued 20 September 1988, assigned to Topre Corporation
Images
References
- ↑ US patent 3918051, Victor M. Bernin, "Key rollover keyboard", issued 25 January 1975
