Editing Capacitive keyboard (patent 3750113)

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. <ref> {{ cite patent | country = US | number = 3750113 | status = patent | title = Capacitive keyboard | pubdate =  | gdate = July 3 1973 | fdate = 12 November 1971 | pridate =  | inventor = J. Arthur Cencel | invent1 =  | invent2 =  | assign1 = Becton Dickinson and Company | assign2 =  | class = }} </ref>

==Abstract==

<blockquote>
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. <br/>
<br/>J. Arthur Cencel <br/> ''Capacitive keyboard''</blockquote>

==Improvements==

<blockquote>
What is claimed as new is:
<br/>
*(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.<br/>

*(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.<br/>

*(3) The data entry system of claim 2 above wherein said low impedance sense amplifier means operates in the current amplifying mode.<br/>

*(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.<br/>

*(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. <br/>

J. Arthur Cencel<br/>''Capacitive keyboard''</blockquote>

==Referenced by==

* {{ cite patent | country = US | number = 3931610 | status = patent | title = Capacitive keyswitch sensor and method | pubdate =  | gdate = 6 January 1976 | fdate = 29 November 1973 | pridate =  | inventor = Robert E. Marin | invent1 = Roger K. Simonson | invent2 = Roger K. Simonson | assign1 = Teletype Corporation | assign2 =  | class = }}
* {{ cite patent | country = US | number = 4074262 | status = patent | title = Key input circuit | pubdate =  | gdate = 14 February 1978 | fdate = 27 January 1973 | pridate =  | inventor = Kosei Nomiya | invent1 = Shinkichi Hotta | invent2 = Shinkichi Hotta | assign1 = Hitachi, Ltd. | assign2 =  | class = }}
* {{ cite patent | country = US | number = 4110748 | status = patent | title = Keyswitch with hysteresis | pubdate =  | gdate = 29 August 1978 | fdate = 6 April 1976 | pridate =  | inventor = Francis C. Marino | invent1 = | invent2 =  | assign1 = Burroughs Corporation | assign2 =  | class = }}
* {{ cite patent | country = US | number = 4222038 | status = patent | title = Microcomputer keyboard input | pubdate =  | gdate = 9 September 1980 | fdate = 24 February 1978 | pridate =  | inventor = Richard A. Magerl | invent1 =  | invent2 =  | assign1 = Motorola, Inc.  | assign2 =  | class = }}
* {{ cite patent | country = US | number = 4288786 | status = patent | title = Touch sensing keyboard construction | pubdate =  | gdate = 8 September 1981 | fdate = 15 January 1979 | pridate =  | inventor = Ferenc Ledniczki | invent1 = Richard J. Patak | invent2 =  | assign1 = Touch Activated Switch Arrays, Inc. | assign2 =  | class = }}
* {{ cite patent | country = US | number = 4390866 | status = patent | title = Keyboard with electronic hysteresis | pubdate =  | gdate = 28 June 1983 | fdate = 19 February 1981 | pridate =  | inventor = Keith A. Engstrom | invent1 =  | invent2 =  | assign1 = Illinois Tool Works, Inc. | assign2 =  | class = }}
* {{ cite patent | country = US | number = 4405917 | status = patent | title = Matrix screening and grounding arrangement | pubdate =  | gdate = 20 September 1983 | fdate = 28 April 1981 | pridate =  | inventor = Thomas Y. Chai | invent1 =  | invent2 =  | assign1 = Honeywell, Inc. | assign2 =  | class = }}
* {{ cite patent | country = US | number = 4408252 | status = patent | title = Low profile keyboard switch | pubdate =  | gdate = 4 October 1983 | fdate = 16 February 1982 | pridate =  | inventor = Andrew Voge | invent1 = Daniel R. Sparks | invent2 = Barry W. Mullins | assign1 = Becton Dickinson and Company | assign2 =  | class = }}
* {{ cite patent | country = US | number = 4412209 | status = patent | title = RC Array | pubdate =  | gdate = 25 October 1983 | fdate = 20 November 1981 | pridate =  | inventor = Norman J. Frame | invent1 = James P. Walber | invent2 = Jan M. Janick | assign1 = W. H. Brady Co. | assign2 =  | class = }}
* {{ cite patent | country = US | number = 4412754 | status = patent | title = Space bar for low profile keyboards | pubdate =  | gdate = 1 November 1983 | fdate = 23 September 1982 | pridate =  | inventor = Daniel R. Sparks | invent1 =  | invent2 =  | assign1 = Becton Dickinson and Company | assign2 =  | class = }}
* {{ cite patent | country = US | number = 4415781 | status = patent | title = Membrane switch | pubdate =  | gdate = 15 November 1983 | fdate = 20 November 1981 | pridate =  | inventor = Norman J. Frame | invent1 = James P. Walber | invent2 = Jan M. Janick | assign1 = W. H. Brady Co. | assign2 =  | class = }}
* {{ cite patent | country = US | number = 4431882 | status = patent | title = Transparent capacitance membrane switch | pubdate =  | gdate = 14 February 1984 | fdate = 12 August 1982 | pridate =  | inventor = Norman J. Frame | invent1 =  | invent2 =  | assign1 = W. H. Brady Co. | assign2 =  | class = }}
* {{ cite patent | country = US | number = 4475142 | status = patent | title = Low profile keyboard switch | pubdate =  | gdate = 2 October 1984 | fdate = 7 September 1983 | pridate =  | inventor = Daniel R. Sparks | invent1 =  | invent2 =  | assign1 = Becton Dickinson and Company | assign2 =  | class = }}
* {{ cite patent | country = US | number = 4494110 | status = patent | title = Keyboard modules for use in data terminals | pubdate =  | gdate = 15 January 1985 | fdate = 3 March 1982 | pridate =  | inventor = Antony J. Wakeling | invent1 = Alan D. Thompson | invent2 =  | assign1 = Schlumberger Electronic (U.K) Ltd. | assign2 =  | class = }}
* {{ cite patent | country = US | number = 4502039 | status = patent | title = Keyboard coding apparatus | pubdate =  | gdate = 26 February 1985 | fdate = 30 April 1982 | pridate =  | inventor = Arturo Vercesi | invent1 = Francesco Marzocca | invent2 =  | assign1 = Honeywell Information Systems Italia | assign2 =  | class = }}
* {{ cite patent | country = US | number = 4591702 | status = patent | title = Digit manipulative data input | pubdate =  | gdate = 27 May 1986 | fdate = 10 April 1981 | pridate =  | inventor = Naveed Alam | invent1 =  | invent2 =  | assign1 =  | assign2 =  | class = }}
* {{ cite patent | country = US | number = 4704601 | status = patent | title = Keyboard data entry system with hysteresis | pubdate =  | gdate = 3 November 1987 | fdate = 27 June 1985  | pridate =  | inventor = Keith A. Engstrom | invent1 =  | invent2 =  | assign1 = Illinois Tool Works Inc. | assign2 =  | class = }}
* {{ cite patent | country = US | number = 4728931 | status = patent | title = Charge redistribution capacitance detection apparatus | pubdate =  | gdate = 1 March 1988 | fdate = 25 July 1986 | pridate =  | inventor = William J. Linder | invent1 = James D. Reinke | invent2 =  | assign1 = Honeywell Inc. | assign2 =  | class = }}
* {{ cite patent | country = US  | number = 4728932 | status = patent | title = Detector for capacitive sensing devices | pubdate =   | gdate = 1 March 1988 | fdate = 25 July 1986 | pridate =  | inventor = James H. Atherton | invent1 =  | invent2 =  | assign1 = Honeywell Inc. | assign2 =  | class = }}
* {{ cite patent | country = US | number = 7564247 | status = patent | title = Operationg element with a proximity sensor and shield | pubdate =  | gdate = 21 July 2009 | fdate = 22 June 2006 | pridate =  | inventor = Frank Born | invent1 = Norbert Mankel | invent2 = Joerg Reinhardt | assign1 = Siemens Aktiengesellschaft | assign2 =  | class = }}
* {{ cite patent | country = US | number = 8040321 | status = patent | title = Touch-sensor with shared capacitive sensors | pubdate =  | gdate = 18 October 2011 | fdate = 10 July 2006 | pridate =  | inventor = Tao Peng | invent1 = Zheng Qin | invent2 =  | assign1 = Cypress Semiconductor Corporation | assign2 =  | class = }}
* {{ cite patent | country = US | number = 8058937 | status = patent | title = Setting a discharge rate and a charge rate of a relaxation oscillator circuit | pubdate =  | gdate = 15 November 2011 | fdate = 30 January 2007 | pridate =  | inventor = Zheng Qin | invent1 = Tao Peng | invent2 =  | assign1 = Cypress Semiconductor Corporation | assign2 =  | class = }}
* {{ cite patent | country = US | number = 8059015  | status = patent | title = Capacitance sensing matrix for keyboards | pubdate =  | gdate = 15 November 2011 | fdate = 25 May 2006 | pridate =  | inventor = Liu Hua | invent1 = Jiang XiaoPing | invent2 =  | assign1 = Cypress Semiconductor Corporation | assign2 =  | class = }}
* {{ cite patent | country = US | number =  | status = patent | title = Apparatus and method for reducing average scan rate to detect a conductive object on a sensing device | pubdate =  | gdate = 27 March 2012 | fdate = 30 March 2006 | pridate =  | inventor = Zheng Qin | invent1 = Tao Peng | invent2 =  | assign1 =  | assign2 =  | class = }}

==Images==

<gallery widths=150 heights=250>
File:capacitive-.png
File:capacitive-1.png
File:capacitive-2.png
</gallery>

==References==
<references/>

[[Category:Patents]]