EP0510057A1 - Detecteur a commande par effleurement - Google Patents

Detecteur a commande par effleurement

Info

Publication number
EP0510057A1
EP0510057A1 EP19910902266 EP91902266A EP0510057A1 EP 0510057 A1 EP0510057 A1 EP 0510057A1 EP 19910902266 EP19910902266 EP 19910902266 EP 91902266 A EP91902266 A EP 91902266A EP 0510057 A1 EP0510057 A1 EP 0510057A1
Authority
EP
European Patent Office
Prior art keywords
touch
detecting means
pad
sensing device
touch pad
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Ceased
Application number
EP19910902266
Other languages
German (de)
English (en)
Inventor
York Varitronix Limited 4/F. Liven House Liao
Michael Y. S. Varitronix Limited Chan
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
BOE Varitronix Ltd
Original Assignee
Varitronix Ltd
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Priority claimed from GB909000624A external-priority patent/GB9000624D0/en
Application filed by Varitronix Ltd filed Critical Varitronix Ltd
Publication of EP0510057A1 publication Critical patent/EP0510057A1/fr
Ceased legal-status Critical Current

Links

Classifications

    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03K—PULSE TECHNIQUE
    • H03K17/00—Electronic switching or gating, i.e. not by contact-making and –breaking
    • H03K17/94—Electronic switching or gating, i.e. not by contact-making and –breaking characterised by the way in which the control signals are generated
    • H03K17/96—Touch switches
    • H03K17/9645—Resistive touch switches

Definitions

  • Touch sensing devices are known in which a single switching arrangement or a multiple selective position sensing arrangement is achieved by touching the device itself or a chosen part of the device respectively. Such devices may make use of membrane switches, optical sensing or electrical capacitive changes.
  • capacitive touch sensing devices are provided with electrically insulating membranes or resin coatings on their operative or exposed surfaces and generally have the drawbacks of poor reliability and poor sensitivity.
  • a touch sensing device comprises an electrically conductive touch pad supported on a insulating substrate, and detecting means electrically connected to the touch pad via a capacitive blocking filter to prevent static electrical charges being applied to the detecting means, wherein' he detecting means detects a change in the impedance at the touch pad caused by a user directly touching the touch pad, in which the detecting means includes an oscillator whose output frequency varies with the change in input impedance.
  • the capacitive touch sensing device may include two or more touch pads each with a respective capacitive blocking filter, and a multiplexer to sequentially connect each capacitor, and hence each touch pad, to the detecting means.
  • the touch pads may each be arranged adjacent a grounded pad such that in use the touch pad can be effectively and selectively bridged to ground when the touch pad is touched by the user.
  • the touch pads may be arranged adjacently in electrically parallel pairs.
  • a touch sensitive pad consists of a number of electrically conductive pads ⁇ o and a surrounding conductive pad 11 supported by an insulating substrate 9.
  • Each pad 10 is electrically connected via a respective blocking capacitor 12 to an analogue multiplexer 13.
  • the surrounding pad 11 is connected to ground.
  • the output of the multiplexer 13 is connected to an oscillator 14.
  • a resistor 15, which may be adjustable, and/or a capacitor 16, which may also be adjustable, are connected to the RC ports of the oscillator 14.
  • the oscillator 14 responds to vary its output frequency from its quiescent frequency. This variation of frequency represents that the pad has been touched and by simultaneously sensing the sequencing of the multiplexer 13, which of the conductive pads 10 that has been touched by the finger is also determined. In this way, whenever the pad is touched, that touching and the position of the finger is determined.
  • the body provides an impedance between the pads 10 and 11 which is effective to change the effective input impedance to the oscillator 14.
  • the detector oscillator 14 responds to such changes in impedance in its input circuit.
  • a touch pad is formed with one or more exposed conductive pads 10 as above except that the surrounding pad 11 is omitted.
  • Each pad 10 is connected via a respective capacitor to the oscillator.
  • the multiplexer 13 is provided where required.
  • the blocking filters 12 prevent static electricity charges being applied to the input of the oscillator. Such charges may be considerable in use and would otherwise destroy the integrated circuit components of the oscillator 14.
  • the capacitors 12 have a preferred value of 100 to 1000 p F .
  • the oscillator frequency is preferably about 100 KH Z .
  • a suitable oscillator is a multivibrator Model CD 4047 supplied by Record Company of America (RCA) .
  • the filters 12 are also filter out direct current components and some electrical noise from a finger applied to the touch pad.
  • touch sensitive pads described have exposed conductive pads which are touched directly in use; this contrasts to the prior art capacitive touch pads.
  • the described pads are simpler to manufacture and have been found to lead to generally more reliable and sensitive operation.
  • the capacitive touch sensing device is used with a display such as a CRT display or, more preferably, a liquid crystal display.
  • the conductive pads are transparent and may be formed, for example, from a deposit of tin oxide laid on the front surface of the display.
  • the device responds in practice to the changes brought about by directly touching the pads which normally result from one or more of the following:-

Landscapes

  • Electronic Switches (AREA)
  • Geophysics And Detection Of Objects (AREA)
  • Push-Button Switches (AREA)
  • Measuring Pulse, Heart Rate, Blood Pressure Or Blood Flow (AREA)
  • Position Input By Displaying (AREA)

Abstract

Element sensible à l'effleurement consistant en un certain nombre d'éléments conducteurs électriques (10) entourés par un élément conducteur (11). Chaque élément (10) est connecté par l'intermédiaire d'un filtre de blocage de capacité respectif à un multiplexeur (13) et à un oscillateur (14). Lorsque l'élément sensible à l'effleurement est touché directement pour établir un pont effectif entre l'un des éléments (10) et l'élément périphérique (11), la modification de l'impédance effective est détectée par une variation résultante de la fréquence de l'oscillateur (14).
EP19910902266 1990-01-11 1991-01-10 Detecteur a commande par effleurement Ceased EP0510057A1 (fr)

Applications Claiming Priority (4)

Application Number Priority Date Filing Date Title
GB9000624 1990-01-11
GB909000624A GB9000624D0 (en) 1990-01-11 1990-01-11 Touch sensing device
GB9020766A GB2241064B (en) 1990-01-11 1990-09-24 Touch sensing device
GB9020766 1990-09-24

Publications (1)

Publication Number Publication Date
EP0510057A1 true EP0510057A1 (fr) 1992-10-28

Family

ID=26296483

Family Applications (1)

Application Number Title Priority Date Filing Date
EP19910902266 Ceased EP0510057A1 (fr) 1990-01-11 1991-01-10 Detecteur a commande par effleurement

Country Status (4)

Country Link
EP (1) EP0510057A1 (fr)
AU (1) AU636003B2 (fr)
CA (1) CA2073676A1 (fr)
WO (1) WO1991011054A1 (fr)

Families Citing this family (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5036321A (en) * 1989-08-31 1991-07-30 Otis Elevator Company Capacitive sensing, solid state touch button system
EP0629981B1 (fr) * 1993-06-21 1998-03-04 Nec Corporation Récepteur d'appel sélectif capable d'arrêter une opération d'avertissement en touchant une chaíne d'attache
US8424350B2 (en) 2009-06-19 2013-04-23 Projections Yoogo Inc. Personal security key holder

Family Cites Families (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE2727522A1 (de) * 1977-06-18 1979-01-04 Licentia Gmbh Sensorschaltfeld, insbesondere fuer einen fernsehempfaenger
CH657240A5 (de) * 1981-11-26 1986-08-15 Inventio Ag Durch beruehrung steuerbare kapazitive schalteinrichtung.
EP0203923B1 (fr) * 1984-02-16 1991-09-11 ANTIKIDIS, Jean-Pierre Procede pour scruter un clavier a touches capacitives et un clavier assorti de moyens pour scruter un clavier selon ce procede

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
See references of WO9111054A1 *

Also Published As

Publication number Publication date
CA2073676A1 (fr) 1991-07-12
WO1991011054A1 (fr) 1991-07-25
AU636003B2 (en) 1993-04-08
AU7064891A (en) 1991-08-05

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Legal Events

Date Code Title Description
PUAI Public reference made under article 153(3) epc to a published international application that has entered the european phase

Free format text: ORIGINAL CODE: 0009012

17P Request for examination filed

Effective date: 19920710

AK Designated contracting states

Kind code of ref document: A1

Designated state(s): DE FR GB

17Q First examination report despatched

Effective date: 19960123

STAA Information on the status of an ep patent application or granted ep patent

Free format text: STATUS: THE APPLICATION HAS BEEN REFUSED

18R Application refused

Effective date: 19970425