EP2057737A1 - Drucktastschalter - Google Patents
DrucktastschalterInfo
- Publication number
- EP2057737A1 EP2057737A1 EP07801923A EP07801923A EP2057737A1 EP 2057737 A1 EP2057737 A1 EP 2057737A1 EP 07801923 A EP07801923 A EP 07801923A EP 07801923 A EP07801923 A EP 07801923A EP 2057737 A1 EP2057737 A1 EP 2057737A1
- Authority
- EP
- European Patent Office
- Prior art keywords
- piezoelectric element
- push
- electrode
- voltage
- button switch
- 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.)
- Withdrawn
Links
- 238000005259 measurement Methods 0.000 claims description 21
- 238000010586 diagram Methods 0.000 description 8
- 238000010276 construction Methods 0.000 description 5
- 238000011156 evaluation Methods 0.000 description 5
- 238000012545 processing Methods 0.000 description 5
- 239000003990 capacitor Substances 0.000 description 2
- 230000003321 amplification Effects 0.000 description 1
- 230000000903 blocking effect Effects 0.000 description 1
- 230000001419 dependent effect Effects 0.000 description 1
- 238000013461 design Methods 0.000 description 1
- 239000002241 glass-ceramic Substances 0.000 description 1
- 238000009413 insulation Methods 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 238000003199 nucleic acid amplification method Methods 0.000 description 1
- 230000003071 parasitic effect Effects 0.000 description 1
- 238000005406 washing Methods 0.000 description 1
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
- H03K17/964—Piezoelectric touch switches
-
- D—TEXTILES; PAPER
- D06—TREATMENT OF TEXTILES OR THE LIKE; LAUNDERING; FLEXIBLE MATERIALS NOT OTHERWISE PROVIDED FOR
- D06F—LAUNDERING, DRYING, IRONING, PRESSING OR FOLDING TEXTILE ARTICLES
- D06F34/00—Details of control systems for washing machines, washer-dryers or laundry dryers
- D06F34/28—Arrangements for program selection, e.g. control panels therefor; Arrangements for indicating program parameters, e.g. the selected program or its progress
- D06F34/30—Arrangements for program selection, e.g. control panels therefor; Arrangements for indicating program parameters, e.g. the selected program or its progress characterised by mechanical features, e.g. buttons or rotary dials
-
- H—ELECTRICITY
- H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
- H10N—ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
- H10N30/00—Piezoelectric or electrostrictive devices
- H10N30/80—Constructional details
- H10N30/802—Circuitry or processes for operating piezoelectric or electrostrictive devices not otherwise provided for, e.g. drive circuits
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01H—ELECTRIC SWITCHES; RELAYS; SELECTORS; EMERGENCY PROTECTIVE DEVICES
- H01H2201/00—Contacts
- H01H2201/02—Piezo element
-
- 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
- H03K2217/96015—Constructional details for touch switches
-
- H—ELECTRICITY
- H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
- H10N—ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
- H10N30/00—Piezoelectric or electrostrictive devices
- H10N30/30—Piezoelectric or electrostrictive devices with mechanical input and electrical output, e.g. functioning as generators or sensors
- H10N30/302—Sensors
Definitions
- the present invention relates to a push-button switch with a piezoelectric element which can be used, for example, in an operating device for a household electronic appliance.
- Such a push-button switch is basically constructed, as shown in Fig. 1.
- the piezoelectric element 10 is arranged, for example, behind a control panel of an electronic household appliance and supported against a fixed base 14. Furthermore, the piezoelectric element 10 is arranged between a first electrode 16 and a second electrode 18, so that when a pressure or a force F is exerted by a finger 19 in the direction of actuation at the two electrodes 16, 18 indicated in FIG is released, which is proportional to the applied force F.
- a pressure or a force F is exerted by a finger 19 in the direction of actuation at the two electrodes 16, 18 indicated in FIG is released, which is proportional to the applied force F.
- pushbutton switches have several advantages over conventional pushbutton switches. Due to the minimal actuation paths no wear of mechanically moving parts; and it is a simple and mechanically robust design of the key switch possible. Furthermore, no breakthroughs or elevations or depressions are necessary in the control panels of the electronic household appliances, for which reason the push-button switch is arranged so that it is moistureproof and the control panel can be easily cleaned.
- a push-button switch of this type with a piezoelectric element is described, for example, in EP 0 553 881 B1.
- the invention has for its object to further develop a push-button switch of the type described above with a piezoelectric element so that a better processing of the generated measurement signal is possible.
- the pushbutton switch according to the invention comprises a piezoelectric element which is arranged between a first electrode and a second electrode such that when a pressure is exerted on the piezoelectric element, an electrical voltage is generated between the first and the second electrode, and an amplifier circuit whose first input is connected to the first electrode of the piezoelectric element and the second input is connected to the second electrode of the piezoelectric element, on.
- the amplifier circuit is operated with a voltage source, and at its output an amplified voltage between the first and the second electrode of the piezoelectric element is generated as a measurement signal.
- an additional voltage source is connected, whose operating voltage is greater than the maximum voltage between the first and the second electrode of the piezoelectric element.
- the voltage generated between the first and the second electrode of the piezoelectric element is output by means of the amplifier circuit as an amplified measuring signal, this measuring signal can in principle be processed more easily.
- the additional voltage source occur at both the inputs and at the output of the amplifier circuit at any time exclusively positive voltage, which also facilitates the further processing of the generated measurement signal.
- the operating voltage of the additional voltage source is about half as large as an operating voltage of the voltage source of the amplifier circuit selected. In this way is the
- the push button switch of the construction described above is used, for example, in an operating device, in particular an operating device for a household electronic appliance, which additionally has a controller with at least one A / D input terminal connected to the output of the amplifier circuit of the at least one push-button , is provided.
- the outputs of the amplifier circuits of a plurality of push-button switches may also be connected to an A / D input terminal of the controller via an analog-multiplexer circuit.
- Fig. 1 is a schematic representation of the mechanical construction of a push-button switch according to the present invention
- Fig. 2 is a schematic block diagram of the structure of a push-button switch according to a first embodiment of the present invention
- 3A to C are schematic timing diagrams of an applied force (F), a voltage generated by the electrodes (Uin) and a measuring signal (Uout) for explaining the operation of the push-button switch of Fig. 2.
- Fig. 4 is a schematic block diagram showing the structure of a push-button switch according to a second embodiment of the present invention.
- 5A and B are schematic timing diagrams of an applied force (F) and a measurement signal (Uout) for explaining the operation of the push-button switch of Fig. 4;
- FIG. 6 is a schematic block diagram of a controller with an analogue
- Multiplexer circuit for further processing of the measurement signals of multiple push-button switch of the invention.
- the push-button of the present invention described below with reference to the accompanying drawings is advantageously used in operating devices, in particular in operating devices of electronic household appliances (cookers, hobs, washing machines, dryers, dishwashers, etc.), without the invention being limited to these applications should be.
- the mechanical structure of the push-button switch substantially corresponds to that of a conventional push-button switch with piezoelectric element.
- a piezoelectric element 10 is arranged behind a control panel 12 of an operating device, for example a glass-ceramic cooktop, and supported against a fixed base 14.
- the piezoelectric element 10 is in this case between a first electrode 16 on the side of the control panel 12 and a second electrode 18 on the side of the fixed base 18 in FIG.
- a force F acts on the piezoelectric element 10 in the actuation direction indicated in FIG. 1 by a finger 19 a charge quantity Q proportional to the force F is released at the two electrodes 16, 18.
- a charge quantity Q proportional to the force F is released at the two electrodes 16, 18.
- About the parasitically or real existing and connected in parallel to the piezoelectric element 10 components of the capacitance (capacitance of the piezoelectric element, etc.) 28 and the resistor (input resistance of the downstream amplifier, insulation resistance of the piezoelectric element, etc.) 30 so creates a voltage Uin.
- This voltage Uin is amplified by an amplifier circuit 20 whose first input (+) is connected to the first electrode 16 and whose second input (-) is connected to the second electrode 18 and which is supplied by a voltage source 22 with an operating voltage Ua.
- the amplifier circuit 20 outputs a correspondingly amplified measurement signal at its output
- Uout for further processing and evaluation, for example to an A / D Input terminal of a control (microprocessor) 36.
- the evaluation of the measurement signal Uout is then carried out by an appropriate software.
- Representations in A each show the time course of a force F exerted on the piezoelectric element 10 of the push-button switch; and the illustrations in B each show the time profile of the voltage Uin generated between the two electrodes 16, 18 of the piezoelectric element 10.
- the case for a relatively long constant key pressure is shown on the left in each case, while the case on the right is illustrated for a relatively short constant keypress.
- an additional voltage source 26 between the second electrode 18 of the piezoelectric element 10 and the reference point 24 of the voltage source 22 of the amplifier circuit 20 is set. If the operating voltage Ub of this additional voltage source 26 is greater than the maximum voltage between the two electrodes 16, 18 of the piezoelectric see element 10, so occur both at the two inputs and on
- the quiescent level of the measurement signal Uout at the output of the amplifier circuit 20 is approximately in the middle of the modulation range, as illustrated in the diagrams of FIG. 3C.
- FIG. 4 shows the circuit construction of a push button switch of the invention for a charge amplifier having a relatively low input impedance.
- the charge amplifier is constructed in this case from the amplifier circuit 20 and one of these capacitors 32 connected in parallel.
- the amount of charge Q flowing out via the parasitically or really present components of the capacitance 28 and of the resistor 30 connected in parallel with the piezoelectric element can be neglected due to the virtual short circuit at the input of the amplifier circuit 20 (with low input impedance) and the very low voltage.
- the voltage at the output of the charge amplifier (20 and 32) returns to zero even if the force F is still applied because of the parasitic or real resistance 34 after a time constant determined by the capacitance 32 and the resistor 34. If the application of force F is then ended, analogously to the above statements in connection with the first exemplary embodiment, this leads to a voltage at the output of the amplifier circuit 20 with reversed polarity, so that positive and negative measuring signals Uout could also occur here.
- an additional voltage source 26 is set between the second electrode 18 of the piezoelectric element 10 and the reference point 24 of the voltage source 22 of the amplifier circuit 20.
- the operating voltage Ub of the additional voltage source 26 is also here preferably about half as large as the operating voltage Ua the voltage source 22 for the amplifier circuit 20, so that the quiescent level of the measurement signal Uout at the output of the charge amplifier 20, 32 is located approximately in the middle of the modulation range.
- Figs. 5A and B The operation of the push-button switch of the second embodiment is further illustrated in Figs. 5A and B.
- the course of a force F exerted on the piezoelectric element 10 is shown over the time t
- the case for a relatively long constant key pressure is also illustrated on the left-hand side
- the case for a relatively short, constant keypress is illustrated on the right-hand side.
- the measurement signal U out of the amplifier circuit 20 (FIG. 2) or of the charge amplifier (FIG. 4) formed by the amplifier circuit 20 and capacitor 32 is supplied, for example, to an A / D input terminal of a controller (eg microprocessor) 36 and to a corresponding one Software evaluated. If several pushbutton switches or piezoelectric elements 10 are to be evaluated by a controller 36, but the controller does not have a sufficient number of A / D input terminals, then several analog measuring signals must be used
- Uout various piezoelectric elements 10 are connected by means of a multiplexer circuit to an A / D input terminal of the controller. This case is schematically illustrated in the circuit diagram of FIG.
- the signal lines of the three analog measuring signals U1, U2, U3 are further connected to an open-drain output S1, S2 or S3 of the controller 36, which in turn are connected to ground. If, for example, the analog measurement signal U1 is to be supplied to the controller 36, then the open-drain outputs S2 and S3 of the controller 36 must be switched to ground. As a result, the anodes D2 and D3 are replaced by the open-drain outputs S2 and S3 via the resistors. R2 and R3 are shorted to ground. The diodes D2 and D3 thus go into the blocking state and prevent superimposition of the measurement signals U2 and U3 on the resistor R4 to the measurement signal U1, which is currently to be evaluated.
- the analog measuring signal U1AD which is lowered by the forward voltage UD1 of the diode D1 and by the voltage divider R1 / R4, is applied to the A / D input terminal of the controller 36:
- U1 AD (U1 -U 01 ) R4 / (R1 + R4)
- the output of the charge amplifier i. the amplifier circuit 20
- Uout the measurement signal
- Push-button switch of the invention use of the above-mentioned advantages of a push-button switch with a piezoelectric element, which is why it can be used in a particularly advantageous manner for an operating device of an electronic household appliance.
Landscapes
- Engineering & Computer Science (AREA)
- Textile Engineering (AREA)
- Electronic Switches (AREA)
- Push-Button Switches (AREA)
Abstract
Description
Claims
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
DE200610041226 DE102006041226B4 (de) | 2006-09-02 | 2006-09-02 | Drucktastschalter |
PCT/EP2007/007500 WO2008028577A1 (de) | 2006-09-02 | 2007-08-28 | Drucktastschalter |
Publications (1)
Publication Number | Publication Date |
---|---|
EP2057737A1 true EP2057737A1 (de) | 2009-05-13 |
Family
ID=38669821
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
EP07801923A Withdrawn EP2057737A1 (de) | 2006-09-02 | 2007-08-28 | Drucktastschalter |
Country Status (5)
Country | Link |
---|---|
US (1) | US7977851B2 (de) |
EP (1) | EP2057737A1 (de) |
CN (1) | CN101512903A (de) |
DE (1) | DE102006041226B4 (de) |
WO (1) | WO2008028577A1 (de) |
Families Citing this family (5)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
DE102009029500A1 (de) * | 2009-09-16 | 2011-03-24 | Huf Hülsbeck & Fürst Gmbh & Co. Kg | Betätigungseinrichtung für ein Kraftfahrzeug |
DE102009047510B3 (de) * | 2009-12-04 | 2011-05-19 | BSH Bosch und Siemens Hausgeräte GmbH | Haushaltsgerät mit einer Bedieneinrichtung und Verfahren zum Bedienen eines Haushaltsgeräts |
DE102010034588A1 (de) * | 2010-08-17 | 2012-02-23 | Johnson Matthey Catalysts (Germany) Gmbh | Schaltanordnung mit einem Piezotaster sowie Verfahren zum Steuern eines Schaltvorgangs mit Hilfe einer derartigen Schaltanordnung |
FR2968418B1 (fr) * | 2010-12-03 | 2013-08-16 | Schneider Electric Ind Sas | Dispositif d'actionnement a voyant et bouton poussoir comportant un tel dispositif |
KR20150024134A (ko) * | 2013-08-26 | 2015-03-06 | 삼성전자주식회사 | 버튼을 이용하는 제어 장치 및 그 제어 방법 |
Family Cites Families (8)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US4328441A (en) * | 1980-01-31 | 1982-05-04 | Minnesota Mining And Manufacturing Company | Output circuit for piezoelectric polymer pressure sensor |
DE3918407C2 (de) * | 1989-06-06 | 1993-12-23 | Deutsche Aerospace | Piezoelektrischer Beschleunigungssensor, insbesondere zur Auslösung von Insassenschutzvorrichtungen in Kraftfahrzeugen |
US5231326A (en) * | 1992-01-30 | 1993-07-27 | Essex Electronics, Inc. | Piezoelectric electronic switch |
US5612623A (en) * | 1994-05-27 | 1997-03-18 | Nippondenso Co., Ltd. | Failure diagnostic apparatus and method for a resistor element |
FR2739936B1 (fr) * | 1995-10-11 | 1997-11-14 | Snecma | Amplificateur de charge differentiel pour capteur piezoelectrique |
JP2002168719A (ja) * | 2000-12-01 | 2002-06-14 | Ngk Spark Plug Co Ltd | 圧電型圧力センサ用チャージアンプ |
EP1537609A2 (de) * | 2002-09-04 | 2005-06-08 | Triad Sensors Inc. | Interface-elektronik für piezoelektrische bauelemente |
DE102005006666A1 (de) * | 2005-02-14 | 2006-08-24 | Fraunhofer-Gesellschaft zur Förderung der angewandten Forschung e.V. | Piezoelektrischer Sensor und dessen Verwendung |
-
2006
- 2006-09-02 DE DE200610041226 patent/DE102006041226B4/de not_active Expired - Fee Related
-
2007
- 2007-08-28 WO PCT/EP2007/007500 patent/WO2008028577A1/de active Application Filing
- 2007-08-28 CN CNA2007800325389A patent/CN101512903A/zh active Pending
- 2007-08-28 EP EP07801923A patent/EP2057737A1/de not_active Withdrawn
- 2007-08-28 US US12/438,584 patent/US7977851B2/en active Active
Non-Patent Citations (1)
Title |
---|
See references of WO2008028577A1 * |
Also Published As
Publication number | Publication date |
---|---|
DE102006041226B4 (de) | 2015-05-13 |
US20100013355A1 (en) | 2010-01-21 |
WO2008028577A1 (de) | 2008-03-13 |
CN101512903A (zh) | 2009-08-19 |
DE102006041226A1 (de) | 2008-03-20 |
US7977851B2 (en) | 2011-07-12 |
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Legal Events
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PUAI | Public reference made under article 153(3) epc to a published international application that has entered the european phase |
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18D | Application deemed to be withdrawn |
Effective date: 20170307 |