AU634295B2 - An electronic switch - Google Patents

An electronic switch Download PDF

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Publication number
AU634295B2
AU634295B2 AU64662/90A AU6466290A AU634295B2 AU 634295 B2 AU634295 B2 AU 634295B2 AU 64662/90 A AU64662/90 A AU 64662/90A AU 6466290 A AU6466290 A AU 6466290A AU 634295 B2 AU634295 B2 AU 634295B2
Authority
AU
Australia
Prior art keywords
electronic switch
switch arrangement
coupled
output voltage
light
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
AU64662/90A
Other versions
AU6466290A (en
Inventor
Roger Barker
Alan Bruce Robinson
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.)
Nokia Services Ltd
Original Assignee
Alcatel Australia 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 to NZ235645A priority Critical patent/NZ235645A/en
Application filed by Alcatel Australia Ltd filed Critical Alcatel Australia Ltd
Priority to AU64662/90A priority patent/AU634295B2/en
Publication of AU6466290A publication Critical patent/AU6466290A/en
Assigned to ALCATEL AUSTRALIA LIMITED reassignment ALCATEL AUSTRALIA LIMITED Amend patent request/document other than specification (104) Assignors: STANDARD TELEPHONES AND CABLES PTY. LIMITED
Application granted granted Critical
Publication of AU634295B2 publication Critical patent/AU634295B2/en
Anticipated expiration legal-status Critical
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
    • H03K17/30—Modifications for providing a predetermined threshold before switching
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
    • G01S17/00—Systems using the reflection or reradiation of electromagnetic waves other than radio waves, e.g. lidar systems
    • G01S17/02—Systems using the reflection of electromagnetic waves other than radio waves
    • G01S17/04—Systems determining the presence of a target
    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03K—PULSE TECHNIQUE
    • H03K17/00—Electronic switching or gating, i.e. not by contact-making and –breaking
    • H03K17/51—Electronic switching or gating, i.e. not by contact-making and –breaking characterised by the components used
    • H03K17/78—Electronic switching or gating, i.e. not by contact-making and –breaking characterised by the components used using opto-electronic devices, i.e. light-emitting and photoelectric devices electrically- or optically-coupled
    • 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
    • H03K17/941—Electronic switching or gating, i.e. not by contact-making and –breaking characterised by the way in which the control signals are generated using an optical detector
    • 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
    • H03K17/945—Proximity switches
    • 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
    • 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
    • H03K17/9627—Optical touch switches
    • 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
    • H03K17/9627—Optical touch switches
    • H03K17/9631—Optical touch switches using a light source as part of the switch
    • 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
    • H03K17/965—Switches controlled by moving an element forming part of the switch
    • H03K17/968—Switches controlled by moving an element forming part of the switch using opto-electronic devices
    • 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
    • H03K2217/941—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 using an optical detector
    • 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
    • H03K2217/941—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 using an optical detector
    • H03K2217/94102—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 using an optical detector characterised by the type of activation
    • H03K2217/94108—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 using an optical detector characterised by the type of activation making use of reflection

Landscapes

  • Physics & Mathematics (AREA)
  • Electromagnetism (AREA)
  • Engineering & Computer Science (AREA)
  • Computer Networks & Wireless Communication (AREA)
  • General Physics & Mathematics (AREA)
  • Radar, Positioning & Navigation (AREA)
  • Remote Sensing (AREA)
  • Electronic Switches (AREA)

Description

1 634295
ORIGINAL
o COMMOWEALTH OF AUSTRALIA 00 PATENTS ACT 1952-1969 iCMPLETE SPECIFICATION FOR THE INVENTION ENTTL o ED COMPLSTE SPECIFICATION FOR THE INVENTION ENTITLED 00 "AN ELECTRONIC SWITCH" 0 0 0 The following statement is a full description of this invention, including the best method of performing it known to us:- 2 This invention relates to electronic switches of the "touch-button" type that have no moving parts.
A known switch of the above-mentioned type is arranged to detect a change of capacitance to earth when an operator's finger is brought into contact with the switch's button zone. An AC signal generator and a means to detect a change of signal strength Is conventionally required for this type of switch, Such generators and detectors are bulky and expensive.
Another known switch of this general type comprises an infra-red transmitter and receiver so arranged that when an article, such as for example, a sheet of paper, or a magnetic tape is brought into proximity, radiation from the transmitter is reflected by the article onto the receiver which thereupon provides a switching signal, A significant disadvantage of this type of switch is that it cannot be used where there is ambient light, particularly varying anmblnt light, which may swamp the receiver and cause false signalling. It is an object of the present invention to provide a switching arrangement of the last-nientioned type which is immune to the effects of amb'ent light, Implementations of such a switching arrangement can provide cheap and robust switches impervious to water, dust and fire, and Is suitable for use in locations exposed to all weather conditions.
According to lie invention there Is provided an electronic switch arrangement comprising a pulsed light transmitter means and a lighl receiver means supported beneath a transparent button zone such that only when the button zone Is obscurred by an article placed on and above the button zone Is pulsed light from said transmitter means reflected by said article to irradiate said receiver means thereby producing a pulsed output voltage therefrom which Is coupled to input S, means of a differentiating circuit means whose output voltage level Is proportional to the rate of change of said pulsed voltage on Its Input means, a signal condition S being produced for switching a device coupled t! said output voltage of said dif- S ferentle! means when said output voltage reaches a predetermined level.
3 0 Preferably, in order to avoid false triggering of the switch by, for example, a shadow passing across the button zone, activation may be delayed until at least two successive pulses irradiate the infra-red receiver.
In order that the invention may be readily carried into effect, embodiments thereof will now be described in relation to the drawings, In which:.
3 Fig, 1 is a schematic diagram of a partial view of a touch-button arrangement of the present invention, Fig. 2 shows a first embodiment of a control means incorporated in Fig. 1, Fig. 3 shows a second embodiment of a control means incorporated in Fig.
1.
Fig, 4 is a time diagram showing the effects of occlusion of the window of the touch button in the operating and non-operating mode, Referring to Fig, 1, touch-button switch 1 comprises a housing 2 having a window 3 therein forming a button zone. Within housing 2 is supported a light emitting diode (LED) 4 and a photo transistor 5. The focal length of the diode and the transistor is optimised so that when a finger of an operator is placed on the exterior surface of window 3, light emitted from LED 4 reflected thereby onto transistor 5, LED 4 and transistor 5 are operatively coupled to control means 6 details of which are shown in Figs. 2 and 3, It will be understood that an integrated photo-reflective sensor can be substituted for the discrete LED and transistor shown in the embodiments, Referring to Fig. 2, the control circuit comprises a pulse generator 7 providing, via limiting resistor R1, a pulse of, for example ,2 m/s ON and ,8 m/s OFF to drive LED 4; a differentiating circuit coupled to the emitter ele-
I
I
4 4 t I i
S
4 4 4 4 4 444' ment of' photo-transistor 5, comprising a RC network of resistors R2, R3 and R'4 and capacitor Cl; and a level detector and output circuit comprisin'g PNF tr'ansistor Ti, resistors R3 and R4 in common with the RC network, and resistor RS; and an output terminal 0/P.
In operation, while the window is unobstructed pulses of infra-red r'adiation generated by LED 4I are beamed out through window 3 and do not irradiate photo -transistor 5. Photo transistor 5 may, however, be irradiated by varying levels of ambient light from outside the window such as, for example, natural light, sunlidit or artificial light. The resulting output from photo transistor 5 is relatively low, and, moreover, it is relatively uninterrupted with slow rise-time variations in voltage level. The RO network blocks "luch s'low rise-time voltages appearing at circuit point VI and therefore the voltage level at circuit point V2 is not sufficient to exceed the cut-off value of transistor Ti and as a result no switch signal condition occurs at the output 0/P.
On operation of the touch-button, the operator's finger' occludes window 3 whereupon most of the ambient light is blocked out and at the same time a substantial level of pulsed infra-red light is reflected by the fiLnger onto photo-transistor 5 causing an increase in the voltage at point VI and, moreover, this voltage is in the form of pulses having precise and steep rising 2and falling edges which are passed by the RC network. As a result the voltage at point V2 now exceeds the cut-off value of transistor Ti. Transistor TI is normally conducting and it now switches off which in turn causes the voltage at circuit point V3 to drop thereby generating a negative going pulse at output 0/P which can be utilized as a switching signal.
In the embodiment shown in Fig. 3, the output 0/P Is coupled to an input means of a processor 8. The processor 8 is programmed to provide pulses of a predetermined rate to LMD 4~ via a buffer means 9. Operation of touch-button will cause a switching signal as described above to be present at the input means of processor 8 which, In the present embodiment, will cause a display means 10 associated with an electronic electricity meter, of an energy management terminal to operate. Such an energy management terminal is described in Australian Patent No. 586,716.
The processor may be programned to delay the operation of a devce such as the aforementioned display until two or more cycles of pulses from LED 41 are received by photo-transistor Additionally, the processor may be programned such that the device, is operated only after the finger is removed from the button zone. This has the advantage of rendering the switch Imiune to the accumulation of dust on bhe window.
While the present invention has been described with regard to mny par- 0 ticulars, it is understood that equivalents may be readily substituted without departing from the scope of the invention.
o- 0 0 i 0 C

Claims (10)

1. An electronic switch arrangement comprising a pulsed light transmitter means and a light receiver means supported beneath a transparent button zone such that only when the button zone is obscurred by an article placed on and above the button zone is pulsed light from said transmitter means reflected by said article to irradiate said receiver means thereby producing a pulsed output voltage therefrom which is coupled to input means of a differentiating circuit means whose output voltage level is proportional to the rate of change of said pulsed voltage on its input means, a signal condition being produced for switching a device coupled to said output voltage of said differential means when said output voltage reaches a predetermined level, 2, An electronic switch arrangement as claimed in claim 1, wherein said dif- ferentiating circuit means comprises an R/C network,
3. An electronic switch arrangement as claimed in claim 1 or 2, wherein said light receiver means comprises a photo-transistor means, a conductive path of which is coupled to said Input means of said differentiating network,
4. An electronic switch arrangement as claimed In any one of the preceding claims, wherein said light transmitter means is a light emitting diode means driven by a pulse generator means, 20 5, An electronic switch as claimed in claim 3 or 4, wherein said photo- transistor means and said light emitting diode means are integrated in a package,
6. An electronic switch arrangement as claimed In any one of the preceding claims, wherein said signal condition provided by the output voltage of said dif- ferentiating circuit means is coupled to an input of a processor means which is programmed to provide a signal condition at an output thereof for switching a de- vice coupled thereto. 7, An electronic switch arrangement as claimed in claim 6, as appended to I claim 4 or 5, wherein said pulse generator means is provided by a further output of said processor means,
8. An electronic switch arrangement as claimed In claim 6 or 7, wherein said processor means Is programmed to provide a signal condition at said an output there only after at least two successive pulses of light Irradiate said receiver means.
9. An electronic switch arrangement as claimed In any one of the preceding claims, wherein the output voltage of the differentliaing means is coupled to a I r" 7 control element of a semiconductor switch means a conductive path of which is coupled to said device, An electronic switch arrangement as claimed In claim 9, wherein said semiconductor switch means is normally on and is rendered non-conducting by the output voltage of said differentiating circuit means,
11. An electronic switch arrangement as claimed In any one of the preceding claims, incorporated in a housing means, said button zone being located in a wall thereof,
12. An electronic switch arrangement as claimed in any one of the preceding claims, wherein said article is an operator's finger,
13. An electronic switch arrangement as claimed in any one of the preceding claims, wherein said light transmitter Is an infra-red light transmitter,
14. An electronic switch arrangement substantially as herein described with reference to Figs, 1 to 4 of the accompanying drawings, 15, An electronic switch arrangement as claimed In any one of the preceding claims Incorporated In the energy management terminal claimed In Australlan Patent No, 586716. DATED THIS SECOND DAY OF DECEMBER 1992. ALCATEL AUSTRALIA LIMITED St$ i 4 ao ial
AU64662/90A 1989-10-26 1990-10-15 An electronic switch Ceased AU634295B2 (en)

Priority Applications (2)

Application Number Priority Date Filing Date Title
NZ235645A NZ235645A (en) 1989-10-26 1990-10-11 Electronic touch switch uses light reflection
AU64662/90A AU634295B2 (en) 1989-10-26 1990-10-15 An electronic switch

Applications Claiming Priority (4)

Application Number Priority Date Filing Date Title
AUPJ7043 1989-10-26
AUPJ704389 1989-10-26
NZ235645A NZ235645A (en) 1989-10-26 1990-10-11 Electronic touch switch uses light reflection
AU64662/90A AU634295B2 (en) 1989-10-26 1990-10-15 An electronic switch

Publications (2)

Publication Number Publication Date
AU6466290A AU6466290A (en) 1991-05-02
AU634295B2 true AU634295B2 (en) 1993-02-18

Family

ID=27155551

Family Applications (1)

Application Number Title Priority Date Filing Date
AU64662/90A Ceased AU634295B2 (en) 1989-10-26 1990-10-15 An electronic switch

Country Status (2)

Country Link
AU (1) AU634295B2 (en)
NZ (1) NZ235645A (en)

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2002045095A2 (en) * 2000-11-28 2002-06-06 3M Espe Ag Medical device with a partially transparent housing
WO2003014903A2 (en) * 2001-08-09 2003-02-20 Novo Nordisk A/S An operating button with a transparent part for optical communication
AT509969B1 (en) * 2010-05-31 2015-06-15 Fronius Int Gmbh METHOD AND DEVICE FOR CARRYING OUT A SWITCHING PROCESS

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO1986001953A1 (en) * 1984-09-22 1986-03-27 Michael John Nobbs Switch
WO1987006077A1 (en) * 1986-04-04 1987-10-08 Robert Bosch Gmbh Opto-electronic display device with proximity detector

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO1986001953A1 (en) * 1984-09-22 1986-03-27 Michael John Nobbs Switch
WO1987006077A1 (en) * 1986-04-04 1987-10-08 Robert Bosch Gmbh Opto-electronic display device with proximity detector

Cited By (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2002045095A2 (en) * 2000-11-28 2002-06-06 3M Espe Ag Medical device with a partially transparent housing
WO2002045095A3 (en) * 2000-11-28 2002-08-15 3M Espe Ag Medical device with a partially transparent housing
EP1648211A2 (en) * 2000-11-28 2006-04-19 3M Espe AG Medical device with a partially transparent housing and use thereof
EP1648211A3 (en) * 2000-11-28 2008-11-26 3M Espe AG Medical device with a partially transparent housing and use thereof
WO2003014903A2 (en) * 2001-08-09 2003-02-20 Novo Nordisk A/S An operating button with a transparent part for optical communication
WO2003014903A3 (en) * 2001-08-09 2004-03-04 Novo Nordisk As An operating button with a transparent part for optical communication
AT509969B1 (en) * 2010-05-31 2015-06-15 Fronius Int Gmbh METHOD AND DEVICE FOR CARRYING OUT A SWITCHING PROCESS

Also Published As

Publication number Publication date
AU6466290A (en) 1991-05-02
NZ235645A (en) 1993-09-27

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