Capacitive keyboard (patent 3750113)
Jump to navigation
Jump to search
A capacitive keyboard is a variable conductive diode matrix with hysteresis capacitance device that was improved by J. Arthur Cencel. Its patent was filed on 1971 and granted on 1973.
Description
Capacitive keyboard
- Inventor: J. Arthur Cencel
- Patent number: 3750113
- Filing date: 12 November 1971
- Issue date: 3 July 1973
An n-bit key capacitive keyboard is coupled to an n-bit shift register. The actuation of the keys results in a variable impedance of the circuit, requiring less pulse on the inactive keys, since the output of the actuated keys also applies to the output of the shift register with the circuit. [1]
Abstract
A n key capacitive keyboard is coupled to an n bit shift register. Each key is sequentially interrogated and if actuated an output pulse appears which is applied to the input of the shift register. The output pulse is also compared to the output of the shift register corresponding to the state of the key in the prior cycle. An output pulse is generated on the first occurrence of signal representing actuation of the key. The output of the shift register is also applied to make the key more sensitive and therefore require less key travel to pass the interrogating pulse.
J. Arthur Cencel
Capacitive keyboard
Improvements
What is claimed as new is:
- (1) A data entry comprising in combination a pulse generating means.
- (b) an output terminal.
- (c) a plurality of keys adapted for individual actuation each key having a different significance in the entry of data.
- (d) a corresponding plurality of capacitive elements each connected to a respective key and adapted to have the capacitance modified in accordance with the actuation of the corresponding key for selectively transmitting pulses applied thereto and e addressing means commonly connected to said capacitance elements and to said pulse generating means and output terminal for sequentially applying pulses to said capacitance elements and for applying the selectively transmitted pulses therefrom to said output terminal in a predetermined order.
- (2) The data entry system of claim 1 above further including low impedance sense amplifier means commonly connected to said capacitance elements through said addressing means for providing an output signal representative of and corresponding to an actuated key.
- (3) The data entry system of claim 2 above wherein said low impedance sense amplifier means operates in the current amplifying mode.
- (4) A data entry system comprising in combination a pulse generating means
- (b) a plurality of keys adapted for individual actuation each key having a different significance in the entry of data
- (c) a corresponding plurality of capacitive elements each connected to a respective key and adapted to have the capacitance modified in accordance with the actuation of the corresponding key for selectively transmitting pulses applied thereto
- (d) Input addressing means commonly connected to said capacitance elements and to said pulse generating means for sequentially applying pulses to said capacitance elements in a predetermined order and storage means including a plurality of storage elements each respectively corresponding to a different key coupled to said capacitive elements said storage means operating in synchronism with said input addressing means for applying the output representative of each key to the storage element respectively corresponding thereto.
- (5) The data entry system of claim 4 above further including hysteresis means coupled to said storage means and responsive to output signals therefrom representing an actuated key for increasing the sensitivity of the capacitive element corresponding to the selected key thereby permitting the transmission of pulses over a wider range of key actuations.
J. Arthur Cencel
Capacitive keyboard
Referenced by
- US patent 3931610, Robert E. Marin & Roger K. Simonson, "Capacitive keyswitch sensor and method", issued 6 January 1976, assigned to Teletype Corporation
- US patent 4074262, Kosei Nomiya & Shinkichi Hotta, "Key input circuit", issued 14 February 1978, assigned to Hitachi, Ltd.
- US patent 4110748, Francis C. Marino, "Keyswitch with hysteresis", issued 29 August 1978, assigned to Burroughs Corporation
- US patent 4222038, Richard A. Magerl, "Microcomputer keyboard input", issued 9 September 1980, assigned to Motorola, Inc.
- US patent 4288786, Ferenc Ledniczki, "Touch sensing keyboard construction", issued 8 September 1981, assigned to Touch Activated Switch Arrays, Inc.
- US patent 4390866, Keith A. Engstrom, "Keyboard with electronic hysteresis", issued 28 June 1983, assigned to Illinois Tool Works, Inc.
- US patent 4405917, Thomas Y. Chai, "Matrix screening and grounding arrangement", issued 20 September 1983, assigned to Honeywell, Inc.
- US patent 4408252, Andrew Voge & Barry W. Mullins, "Low profile keyboard switch", issued 4 October 1983, assigned to Becton Dickinson and Company
- US patent 4412209, Norman J. Frame & Jan M. Janick, "RC Array", issued 25 October 1983, assigned to W. H. Brady Co.
- US patent 4412754, Daniel R. Sparks, "Space bar for low profile keyboards", issued 1 November 1983, assigned to Becton Dickinson and Company
- US patent 4415781, Norman J. Frame & Jan M. Janick, "Membrane switch", issued 15 November 1983, assigned to W. H. Brady Co.
- US patent 4431882, Norman J. Frame, "Transparent capacitance membrane switch", issued 14 February 1984, assigned to W. H. Brady Co.
- US patent 4475142, Daniel R. Sparks, "Low profile keyboard switch", issued 2 October 1984, assigned to Becton Dickinson and Company
- US patent 4494110, Antony J. Wakeling, "Keyboard modules for use in data terminals", issued 15 January 1985, assigned to Schlumberger Electronic (U.K) Ltd.
- US patent 4502039, Arturo Vercesi, "Keyboard coding apparatus", issued 26 February 1985, assigned to Honeywell Information Systems Italia
- US patent 4704601, Keith A. Engstrom, "Keyboard data entry system with hysteresis", issued 3 November 1987, assigned to Illinois Tool Works Inc.
- US patent 4728931, William J. Linder, "Charge redistribution capacitance detection apparatus", issued 1 March 1988, assigned to Honeywell Inc.
- US patent 4728932, James H. Atherton, "Detector for capacitive sensing devices", issued 1 March 1988, assigned to Honeywell Inc.
- US patent 7564247, Frank Born & Joerg Reinhardt, "Operationg element with a proximity sensor and shield", issued 21 July 2009, assigned to Siemens Aktiengesellschaft
- US patent 8040321, Tao Peng, "Touch-sensor with shared capacitive sensors", issued 18 October 2011, assigned to Cypress Semiconductor Corporation
- US patent 8058937, Zheng Qin, "Setting a discharge rate and a charge rate of a relaxation oscillator circuit", issued 15 November 2011, assigned to Cypress Semiconductor Corporation
- US patent 8059015, Liu Hua, "Capacitance sensing matrix for keyboards", issued 15 November 2011, assigned to Cypress Semiconductor Corporation
- US patent, Zheng Qin, "Apparatus and method for reducing average scan rate to detect a conductive object on a sensing device", issued 27 March 2012
Images
References
- ↑ US patent 3750113, J. Arthur Cencel, "Capacitive keyboard", issued July 3 1973, assigned to Becton Dickinson and Company
