GB2234352A - Touch sensitive switches - Google Patents

Touch sensitive switches Download PDF

Info

Publication number
GB2234352A
GB2234352A GB8916980A GB8916980A GB2234352A GB 2234352 A GB2234352 A GB 2234352A GB 8916980 A GB8916980 A GB 8916980A GB 8916980 A GB8916980 A GB 8916980A GB 2234352 A GB2234352 A GB 2234352A
Authority
GB
United Kingdom
Prior art keywords
layer
plastics material
electrode
touch sensitive
electrodes
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.)
Granted
Application number
GB8916980A
Other versions
GB2234352B (en
GB8916980D0 (en
Inventor
Christopher James Cooper
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.)
Diamond H Controls Ltd
Original Assignee
Diamond H Controls 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
Application filed by Diamond H Controls Ltd filed Critical Diamond H Controls Ltd
Priority to GB8916980A priority Critical patent/GB2234352B/en
Publication of GB8916980D0 publication Critical patent/GB8916980D0/en
Publication of GB2234352A publication Critical patent/GB2234352A/en
Application granted granted Critical
Publication of GB2234352B publication Critical patent/GB2234352B/en
Anticipated expiration legal-status Critical
Expired - Fee Related 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
    • H03K17/962—Capacitive touch switches
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01H—ELECTRIC SWITCHES; RELAYS; SELECTORS; EMERGENCY PROTECTIVE DEVICES
    • H01H13/00—Switches having rectilinearly-movable operating part or parts adapted for pushing or pulling in one direction only, e.g. push-button switch
    • H01H13/70—Switches having rectilinearly-movable operating part or parts adapted for pushing or pulling in one direction only, e.g. push-button switch having a plurality of operating members associated with different sets of contacts, e.g. keyboard
    • H01H13/702—Switches having rectilinearly-movable operating part or parts adapted for pushing or pulling in one direction only, e.g. push-button switch having a plurality of operating members associated with different sets of contacts, e.g. keyboard with contacts carried by or formed from layers in a multilayer structure, e.g. membrane switches
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01H—ELECTRIC SWITCHES; RELAYS; SELECTORS; EMERGENCY PROTECTIVE DEVICES
    • H01H2209/00—Layers
    • H01H2209/016—Protection layer, e.g. for legend, anti-scratch
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01H—ELECTRIC SWITCHES; RELAYS; SELECTORS; EMERGENCY PROTECTIVE DEVICES
    • H01H2209/00—Layers
    • H01H2209/068—Properties of the membrane
    • H01H2209/082—Properties of the membrane transparent
    • H01H2209/084—Glass
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01H—ELECTRIC SWITCHES; RELAYS; SELECTORS; EMERGENCY PROTECTIVE DEVICES
    • H01H2239/00—Miscellaneous
    • H01H2239/006—Containing a capacitive switch or usable as such
    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03K—PULSE TECHNIQUE
    • H03K2217/00—Indexing scheme related to electronic switching or gating, i.e. not by contact-making or -breaking covered by H03K17/00
    • H03K2217/94—Indexing scheme related to electronic switching or gating, i.e. not by contact-making or -breaking covered by H03K17/00 characterised by the way in which the control signal is generated
    • H03K2217/96—Touch switches
    • H03K2217/9607—Capacitive touch switches
    • H03K2217/960755—Constructional details of capacitive touch and proximity switches
    • H03K2217/96077—Constructional details of capacitive touch and proximity switches comprising an electrode which is floating
    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03K—PULSE TECHNIQUE
    • H03K2217/00—Indexing scheme related to electronic switching or gating, i.e. not by contact-making or -breaking covered by H03K17/00
    • H03K2217/94—Indexing scheme related to electronic switching or gating, i.e. not by contact-making or -breaking covered by H03K17/00 characterised by the way in which the control signal is generated
    • H03K2217/96—Touch switches
    • H03K2217/9607—Capacitive touch switches
    • H03K2217/960755—Constructional details of capacitive touch and proximity switches
    • H03K2217/960775—Emitter-receiver or "fringe" type detection, i.e. one or more field emitting electrodes and corresponding one or more receiving electrodes

Landscapes

  • Switches That Are Operated By Magnetic Or Electric Fields (AREA)
  • Push-Button Switches (AREA)

Abstract

A touch sensitive capacitive switch comprising a layer 11 of plastics material acting as a dielectric, a first electrode 17 which is on one side of the layer 11 and second and third electrodes 18, 19 on the other side eg carried by further plastics layers 12, 13, the second and third electrodes 18, 19 being spaced and in register with respective parts of the first electrode 17. The layer 11 of plastics material is adhered to a glass layer 10 so that the first electrode 17 is between the layer 11 of plastics material and the glass layer 10. <IMAGE>

Description

TOUCH SENSITIVE SWITCHES This invention relates to a touch sensitive switch.
It is known to provide a touch sensitive switch as illustrated in Figure 1 which has a glass sheet 1 on a first surface of which (the lower surface in Figure 1) there are formed spaced electrodes 2 and 3. On the opposite surface (the upper surface in Figure 1) there is formed another electrode 4 facing the electrodes 2 and 3; electrodes 2 and 3 are connected, respectively, to a signal source 5 and a signal detector 6. The capacitance between electrodes 2 and 3 is affected by the presence of the electrode 4 on the top surface of the glass sheet 1. The signal source 5 is connected to the signal detector 6 via this capacitance. When a person touches the electrode 4, he or she provides a capacitance between that electrode and ground and thereby changes the capacitance between the electrodes 2 and 3.As a result, the level of the signal received by the signal detector 6 changes and this is used to control some device.
The touch sensitive switch illustrated in Figure 1 has been used successfully but is expensive to manufacture, firstly because it is necessary to deposit the electrodes 2, 3 and 4 on opposite sides of the glass.
Moreover in order to connect the electrodes 2 and 3 to the signal source and signal detector 5 and 6 respectively, it is necessary to deposit tracks on the lower surface of the glass sheet 1 and this is of course normally done at the same time as the deposition of the electrodes 2 and 3. These deposition steps are, in practice, expensive and supplies of the glass sheets of the required dielectric characteristics are not entirely satisfactory.
As has already been explained, it is necessary to provide tracks on the lower surface of the glass sheet to provide connections to the electrodes or pads 2 and 3. The very presence of the tracks provides inter-track capacitance which affects the operation of the switch.
It is, in fact, possible to avoid providing tracks on the lower surface of the glass sheet l by providing spring contacts to the electrodes 2 and 3 but this is also an expensive design.
The capacitance between the electrodes 2 and 3 is also changed when a person brings his finger sufficiently close to the electrode 4 (without actually touching the electrode 4) to provide capacitance for ground and to thereby operate the switch. The expression "touch" throughout the specification and claims is to be understood to include operation in this manner.
It is an object of this invention to provide an improved touch sensitive switch in which the problems associated with the known touch sensitive switch are at least alleviated.
According to this invention, there is provided a touch sensitive switch comprising a layer of plastics material acting as a dielectric, a first electrode which is on one side of the layer and second and third electrodes on the other side, the second and third electrodes being spaced and in register with the first electrode.
Preferably, the layer of plastics material is adhered to a layer of backing material so that the first electrode is between the layer of plastics material and the layer of backing material.
Preferably the layer of backing material is of glass.
In one arrangement in accordance with the invention, the second layer of plastics material is adhered to the first mentioned layer and a third layer of plastics material is adhered to the second layer of plastics material so that the first mentioned, the second and the third layers of plastics material are parallel, the first electrode being formed on the surface of the first mentioned plastics layer remote from the second and third layer of the plastics material, and the second and third electrodes being formed respectively on those surfaces of the second and third layers of plastics material remote from the first electrode, and the second and third electrodes being connected to metallic tracks formed on the respective surfaces of the second and third layers of plastics material respectively.
Preferably the third electrode is connected via its metallic track to a surface mounted component on the surface of the third layer remote from the first mentioned layer.
In another construction in accordance with this invention, a second layer of plastics material is adhered by an adhesive material to the first mentioned layer of plastics material so that the first mentioned and the second layer of the plastics material are parallel, the first and second electrodes being formed on opposite surfaces of the first layer of plastics material with the first electrode on the surface remote from the second layer of plastics material, the third electrode being formed on the surface of the second layer of plastics material remote from the first layer of plastics material, the second and third electrodes being connected to metallic tracks formed on the respective surfaces of the first and second layers.
The third electrode is connected by its metallic track to a component mounted on the surface of the second layer of the plastics material remote from the first layer of the plastics material.
Preferably the layer or layers is or are in the form of a film.
Preferably the plastics layers are of polyester.
An embodiment of this invention will now be described, by way of example only, with reference to the accompanying drawings of which: Figure 1 is a schematic view of a known touch sensitive switch which has already been described; Figure 2 is a sectional elevation of a first touch sensitive switch in accordance with this invention; and Figure 3 is a sectional elevation of a second touch sensitive switch in accordance with this invention.
Referring to Figure 2 a glass sheet 10 has adhered to it plastic layers ll, 12 and 13 in that order by respective adhesive layers 14, 15 and 16. A plurality of switches have a common glass sheet 10 and common plastic layers ll, 12 and 13 and only one switch will be described. A touch pad or electrode 17 is formed on the surface of the plastics layer 11 adhered to the glass layer 10.
The layer 12 has a source electrode 18 formed on it on the surface furthest from the glass sheet 10 and is connected, by a metallic track formed on the layer 12 to a signal source (not shown). The layer 13 has formed on it a detector electrode 19 and carries a surface mounted component 20 on the surface remote from the glass sheet 10; the electrodes 18 and 19 are in register with different parts of the touch electrode 17 on the layer 11. The electrode 19 is connected via a metallic track and the surface mounted component 20 to a signal detector (not shown).
The electrodes 18 and 19 cannot be formed on the same plastics layer because of the connecting track path which need to cross.
The surface mounted components can be buffer transistor circuits which permit multiplexing of the switch matrix reducing the number of connections required. The connections may be brought out in tails in the same way as with membrane switch panels.
The glass layer 10 does not act as the dielectric for the capacitance between the electrodes 17, 18 and 19, which is provided by layers 11, 12 and 13 which may be of polyester. The capacitance between the source and detector electrodes 18 and 19 is made up of the capacitance between the electrodes 18 and 19 and that between the electrodes 17 and 19 and is altered when a person touches the glass sheet 10 above electrode 17.
It will be observed that in the embodiment illustrated in Figure 2, no conductive layers or electrode are printed on to glass sheet 10 which remove an expensive processs and enables standard inexpensive glass sheet to t 'Noreover as all the plastic layers are behind the glass sheet 10 they can be protected from adverse conditions. This is particularly useful on hob controls where previously the top pad was external and had to be resistant to heat and abrasion. In this connection reference is made to pad 4 of Figure 1 which is external and had to be protected.
Film layers of plastic material such as layers 11, 12 and 13 can be relatively cheap to produce.
It will be appreciated that in use the user merely touches the glass layer 10 in line with the electrode on layer 11. Although the user does not actually touch the electrode 17 on the layer 11, he changes the capacitance between the electrodes 18 and 19 sufficiently to change the signal applied between the signal source and the signal detector.
The embodiment of Figure 3 differs from that of Figure 1 in that the plastics layer 12 and adhesive layer 15 are eliminated and, instead, touch electrode 18 (and its track) are formed on the surface of the layer 14 furthest from the glass sheet 10. The layer 13 is adhered to layer 11 by the adhesive layer 16.

Claims (10)

1. A touch sensitive switch comprising a layer of plastics material acting as a dielectric, a first electrode which is on one side of the layer and second and third electrodes on the other side, the second and third electrodes being spaced and in register with the first electrode.
2. A touch sensitive switch according to Claim 1, wherein the layer of plastics material is adhered to a layer of backing material so that the first electrode is between the layer of plastics material and the layer of backing material.
3. A touch sensitive switch according to Claim 2, wherein the layer of backing material is of glass.
4. A touch sensitive switch according to any of claims 1 to 3, wherein the second layer of plastics material is adhered to the first mentioned layer and a third layer of plastics material is adhered to the second layer of plastics material so that the first mentioned, the second and the third layers of plastics material are parallel, the first electrode being formed on the surface of the first mentioned plastics layer remote from the second and third layer of the plastics material, and the second and third electrodes being formed respectively on those surfaces of the second and third layers of plastics material remote from the first electrode, and the second and third electrodes being connected to metallic tracks formed on the respective surfaces of the second and third layers of plastics material respectively.
5. A touch sensitive switch according to Claim 4, wherein the third electrode is connected via its metallic track to a surface mounted component on the surface of the third layer remote from the first mentioned layer.
6. A touch sensitive switch according to any of claims 1 to 3, wherein a second layer of plastics material is adhered by an adhesive material to the first mentioned layer of plastics material so that the first mentioned and the second layer of the plastics material are parallel, the first and second electrodes being formed on opposite surfaces of the first layer of plastics material with the first electrode on the surface remote from the second layer of plastics material, the third electrode being formed on the surface of the second layer of plastics material remote from the first layer of plastics material, the second and third electrodes being connected to metallic tracks formed on the respective surfaces of the first and second layers.
7. A touch sensitive switch according to Claim 6, wherein the third electrode is connected by its metallic track to a component mounted on the surface of the second layer of the plastics material remote from the first layer of the plastics material.
8. A touch sensitive switch according to any of claims 1 to 7, wherein the layer or layers is or are in the form of a film.
9. A touch sensitive switch according to any of claims 1 to 8, wherein the plastics layers are of polyester.
10. A touch sensitive switch substantially as hereinbefore described with reference to Figures 2 and 3 of the accompanying drawings.
GB8916980A 1989-07-25 1989-07-25 Touch sensitive switches Expired - Fee Related GB2234352B (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
GB8916980A GB2234352B (en) 1989-07-25 1989-07-25 Touch sensitive switches

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
GB8916980A GB2234352B (en) 1989-07-25 1989-07-25 Touch sensitive switches

Publications (3)

Publication Number Publication Date
GB8916980D0 GB8916980D0 (en) 1989-09-13
GB2234352A true GB2234352A (en) 1991-01-30
GB2234352B GB2234352B (en) 1994-05-18

Family

ID=10660588

Family Applications (1)

Application Number Title Priority Date Filing Date
GB8916980A Expired - Fee Related GB2234352B (en) 1989-07-25 1989-07-25 Touch sensitive switches

Country Status (1)

Country Link
GB (1) GB2234352B (en)

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2245710A (en) * 1990-06-24 1992-01-08 Barkley & Dexter Lab Inc Search coil assembly with laminate frame members and method for making same
EP1583122A1 (en) * 2004-03-29 2005-10-05 Dickert Electronic GmbH Code lock
DE102005059067A1 (en) * 2005-12-08 2007-06-14 Fela Hilzinger Gmbh Leiterplattentechnik Capacitive panel device manufacturing method, involves forming parts of conductive path layer and/or structured conductive path layer with electronic components and/or electronic switching devices and/or pin-and socket connectors
EP1894712A1 (en) 2006-08-28 2008-03-05 Gorenje Gospodinjski aparati d.d. Touch sensitive foil and a switch made thereof
US7652220B2 (en) 2005-08-19 2010-01-26 E.G.O. Elektro-Geraetebau Gmbh Sensor device
DE102008052324A1 (en) * 2008-10-20 2010-04-22 Ident Technology Ag Contact-/proximity detection device for e.g. switch device, of glass-ceramic hobs in household appliance, has detector electrode coupled with device by modulator, where device detects capacitive couplings between structure and fingers

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2016704A (en) * 1978-03-16 1979-09-26 Texas Instruments Inc Capacitive Touch Switch Panel and Method of Fabricating Same
GB2060895A (en) * 1979-09-28 1981-05-07 Bfg Glassgroup Capacitive touch control switch panels and method of manufacturing them
GB2090979A (en) * 1981-01-14 1982-07-21 Glaverbel Proximity control switching panels

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2016704A (en) * 1978-03-16 1979-09-26 Texas Instruments Inc Capacitive Touch Switch Panel and Method of Fabricating Same
GB2060895A (en) * 1979-09-28 1981-05-07 Bfg Glassgroup Capacitive touch control switch panels and method of manufacturing them
GB2090979A (en) * 1981-01-14 1982-07-21 Glaverbel Proximity control switching panels

Cited By (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2245710A (en) * 1990-06-24 1992-01-08 Barkley & Dexter Lab Inc Search coil assembly with laminate frame members and method for making same
EP1583122A1 (en) * 2004-03-29 2005-10-05 Dickert Electronic GmbH Code lock
US7652220B2 (en) 2005-08-19 2010-01-26 E.G.O. Elektro-Geraetebau Gmbh Sensor device
DE102005059067A1 (en) * 2005-12-08 2007-06-14 Fela Hilzinger Gmbh Leiterplattentechnik Capacitive panel device manufacturing method, involves forming parts of conductive path layer and/or structured conductive path layer with electronic components and/or electronic switching devices and/or pin-and socket connectors
DE102005059067B4 (en) * 2005-12-08 2014-07-10 FELA GmbH Capacitive keyboard device
EP1894712A1 (en) 2006-08-28 2008-03-05 Gorenje Gospodinjski aparati d.d. Touch sensitive foil and a switch made thereof
DE102008052324A1 (en) * 2008-10-20 2010-04-22 Ident Technology Ag Contact-/proximity detection device for e.g. switch device, of glass-ceramic hobs in household appliance, has detector electrode coupled with device by modulator, where device detects capacitive couplings between structure and fingers
DE102008052324B4 (en) * 2008-10-20 2010-09-30 Ident Technology Ag Switch device for hob

Also Published As

Publication number Publication date
GB2234352B (en) 1994-05-18
GB8916980D0 (en) 1989-09-13

Similar Documents

Publication Publication Date Title
US5572205A (en) Touch control system
US4380007A (en) Proximity switch
US4743895A (en) Capacitive switches
KR100685954B1 (en) Touch Panel
US4123631A (en) Touch switch
US4290052A (en) Capacitive touch entry apparatus having high degree of personal safety
US4394643A (en) Capacitive touch panel control
US4975676A (en) Glass membrane touch-controlled circuit apparatus for voltage selection
EP2110834B1 (en) Touch switch structure
US5432671A (en) Device forming tactile screen of the capacitive type
US4090092A (en) Shielding arrangement for a capacitive touch switch device
EP2033081B1 (en) Multi-touch active display keyboard
US4302647A (en) Membrane touch switches
EP0624279A1 (en) A touch responsive control panel.
KR100469355B1 (en) touch panel for display device
US20040080486A1 (en) Transparent overlay input device
US20100053087A1 (en) Touch sensors with tactile feedback
WO2001052416A1 (en) Flexible touchpad sensor grid for conforming to arcuate surfaces
KR20130126228A (en) Matrix switching type touch screen panel having pressure sensor
US20220004268A1 (en) System for detecting a clicked state and an unclicked state of a button for capacitive touch device
US4307383A (en) Touch sensitive control panel utilizing pyroelectric material
GB2234352A (en) Touch sensitive switches
US6958459B2 (en) Contact switching arrangement
US20200233557A1 (en) Input device
JPS59119621A (en) Touch input device

Legal Events

Date Code Title Description
732E Amendments to the register in respect of changes of name or changes affecting rights (sect. 32/1977)
PCNP Patent ceased through non-payment of renewal fee

Effective date: 19950725