WO2014101943A1 - Circuit d'attaque pour capteur capacitif d'entrefer - Google Patents

Circuit d'attaque pour capteur capacitif d'entrefer Download PDF

Info

Publication number
WO2014101943A1
WO2014101943A1 PCT/EP2012/076957 EP2012076957W WO2014101943A1 WO 2014101943 A1 WO2014101943 A1 WO 2014101943A1 EP 2012076957 W EP2012076957 W EP 2012076957W WO 2014101943 A1 WO2014101943 A1 WO 2014101943A1
Authority
WO
WIPO (PCT)
Prior art keywords
sensor
circuit
connector
sensor electrode
measurement device
Prior art date
Application number
PCT/EP2012/076957
Other languages
English (en)
Inventor
Michel Cochard
Julien Pasquier
Original Assignee
Mc-Monitoring S.A.
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 Mc-Monitoring S.A. filed Critical Mc-Monitoring S.A.
Priority to PCT/EP2012/076957 priority Critical patent/WO2014101943A1/fr
Publication of WO2014101943A1 publication Critical patent/WO2014101943A1/fr

Links

Classifications

    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01B—MEASURING LENGTH, THICKNESS OR SIMILAR LINEAR DIMENSIONS; MEASURING ANGLES; MEASURING AREAS; MEASURING IRREGULARITIES OF SURFACES OR CONTOURS
    • G01B7/00—Measuring arrangements characterised by the use of electric or magnetic techniques
    • G01B7/14—Measuring arrangements characterised by the use of electric or magnetic techniques for measuring distance or clearance between spaced objects or spaced apertures

Definitions

  • the present invention relates to the field of contactless distance measurement, and in particular to sensors for detecting variations in a small separation distance by measuring changes in a capacitance parameter.
  • the invention has application for example in the monitoring of vibrations in systems with large rotating elements, such as engines, motors, turbines or generators.
  • Contactless distance sensors are regularly used to monitor the position of elements, or the separation distance between elements in machinery such as motors, generators, turbines or machine tools. Such sensors may be required to monitor slowly or rapidly moving parts with a high resolution. For example, a rotor of a generator may exhibit high-frequency vibrations, and a sensor mounted in the stator of the generator may be required to monitor any deformations of the rotor by measuring the rapidly varying gap distance between the sensor surface and the rotor pole surfaces.
  • Such sensors may be placed deep inside machinery, in inaccessible locations where there is no room to include circuitry, or where local intense magnetic fields make it difficult to include circuitry for signal processing, filtering or amplification. For this reason, it is advantageous to connect the sensor to the processing circuitry via a cable which has its own capacitance, depending on its length, and its capacitance may vary significantly as a result of changes in temperature, humidity etc. It is desirable therefore to find ways of reducing or eliminating the effects of the sensor cable capacitance from the sensor signal.
  • Granted Swiss patent CH696895A5 filed by the same applicant as the present application, describes a sensor arrangement which measures a gap distance by measuring the varying capacitance between a sensor electrode and the target electrode (which may be the rotor surface in the example mentioned).
  • the capacitance thus formed by the sensor and target electrodes is incorporated in an RC resonant circuit, such that the resonance characteristics of the circuit at any one time are dependent on the size of the gap distance at that time.
  • the capacitance to be measured may typically be significantly smaller than capacitances inherent in the elements of the sensor circuitry (referred to hereinafter as parasitic capacitances), in particular the capacitance of the cable which connects the sensor to the external circuit elements.
  • the sensor might be required to measure variations in a capacitance of 1 pF or less, for example, while the capacitance of the cable might be as much as 500pF.
  • the effects of varying parasitic capacitance can be mitigated by enclosing or surrounding the sensor electrode in a grounded shielding envelope.
  • a further improvement is proposed using a double shielding arrangement, in which an intermediate sensor-shielding envelope, known as the guard electrode, is placed around the sensor electrode and within the grounded shielding envelope.
  • the sensor electrode and guard electrode are connected to a driver circuit which is designed to maintain both the sensor and guard electrodes at the same potential.
  • any capacitance between the sensor and guard electrodes and/or between their connecting wires should have little or no effect on the resonance parameters of the circuit.
  • the sensor electrode is excited by a high frequency alternating voltage, and the sensor electrode circuit behaves effectively as an RC passfilter circuit, whose transfer function depends on the capacitance between the sensor electrode and the target, the parasitic capacitance associated with the connection cable being more or less
  • the circuit of CH696895 must be tuned to the particular physical and electrical characteristics of the cable/sensor combination (value of R, length of cable, sensor dimensions etc), to ensure that the desired
  • the small variations in output voltage from the passfilter are then detected from the guard electrode connector and amplified for transmission via another cable to remote signal processing circuitry which converts the measured voltage into a measure of the distance between the sensor electrode and the target.
  • the voltage on the guard electrode (and hence the inner shield of the triaxial cable, is modulated by variations in the voltage on the sensor electrode.
  • the RC arrangement described in CH696895A5 has a resonant frequency which depends on the in-circuit resistor and the (varying)
  • the RC resonant circuit can be arranged such that the variations in the capacitance result in an output signal which lies in a part of the frequency/amplitude transfer function which has a steep gradient, thereby offering a large amplification of the signal, which can be further amplified for transmission along a cable. Further linearization of the output signal is then required, and is performed by additional processing circuitry.
  • US2002/0140440 describes a capacitive sensor arrangement in which a sensor-to-target capacitance is measured as a relaxation period or oscillation frequency of a relaxation oscillator, which varies depending on the value of the sensor-target capacitance. In order to ensure an easily-measurable time-period, the resistor is made as large as possible. US2002/01240440 does not relate to the problem of locating the driver circuitry remotely from the sensor electrode, and its oscillator components would need to be integrated with the sensor electrode. This presents difficulties in providing sufficient space at the measurement location. It also restricts the access to the oscillator components in the case where a component must be replaced or adjusted.
  • the invention described in this application seeks to overcome some of the above and other difficulties inherent in the prior art.
  • One problem which the invention aims to overcome is that of simplifying the construction of the driver circuit of CH696895, while keeping the sensor electrode separate from the driver circuitry, and while reducing the need for careful tuning of the driver components to the particular sensor environment.
  • the invention aims to provide a driver circuit for a capacitive small-distance measurement sensor, the driver circuit comprising an astable oscillator circuit, wherein the relaxation time-constant of the astable oscillator circuit is determined by a resistance, referred to hereafter as the time-constant resistance, and by a capacitance of the measurement sensor, wherein the astable oscillator circuit comprises a bistable switching element having an input and an output, wherein the driver circuit is configured to be connected to the measurement sensor via a shielded sensor connector cable comprising at least a first inner connector, a second inner connector and an outer shielding layer, the sensor connector cable comprising a sensor end and a driver end, and wherein the time-constant resistance and the bistable switching element are both arranged at the driver end of the sensor connector cable.
  • the driver circuit comprising an astable oscillator circuit, wherein the relaxation time-constant of the astable oscillator circuit is determined by a resistance, referred to hereafter as the time-constant resistance, and by a capac
  • the bistable switching element is a Schmitt trigger.
  • the measurement sensor is a capacitive sensor having a sensor electrode and a guard electrode
  • the driver circuit is configured to be connected to the sensor electrode via the first inner connector and to the guard electrode via the second inner connector.
  • the input of the bistable switching circuit is connected to the first inner connector and thereby to the sensor electrode.
  • the output of the bistable switching element is connected via the time-constant resistance to the second inner connector and thereby to the guard electrode.
  • a follower circuit is interposed between the time-constant resistance and the second inner connector.
  • the time- constant resistance is connected between the second inner connector and a common ground.
  • one of the first and second inner connectors is formed as an intermediate shielding layer, disposed between the outer shielding layer and the other one of the first and second inner connectors.
  • the second inner connector is formed as the intermediate shielding layer.
  • the driver circuit further comprises a demodulator circuit, and the demodulator circuit is arranged to demodulate an output of the astable oscillator circuit so as to generate a voltage which varies with the frequency of the output of the astable oscillator.
  • the demodulator circuit comprises a phase-locked loop.
  • the astable oscillator circuit and the demodulator circuit are galvanically isolated from one another.
  • the astable oscillator circuit and the demodulator circuit are connected to each other by a shielded cable.
  • Figure 1 shows an example of a sensor arrangement and driver circuit according to a first embodiment of the invention.
  • a capacitive sensor electrode 1 and its associated guard electrode 4 are shown isolated from each other by electrode dielectric 3.
  • the electrode assembly 1 , 3, 4 may for example be incorporated into the inner surface of the stator of a turbine or motor, which will normally be grounded. In this case a further dielectric (not shown) would insulate the guard electrode from the surrounding machinery (not shown).
  • the target 2, which is at a small distance (much exaggerated in the schematic illustration) away from the sensor electrode 1 may for example be a part of the rotor of the generator, turbine etc.
  • the separation distance may be of the order of 0.1 mm, for example, or in other cases as much as 50mm, and a variation in the separation distance (due to thermal expansion or contraction of the rotor and/or the stator, for example) will result in a change in the capacitance between the sensor electrode 1 and the (grounded) target 2.
  • the illustrated circuit comprises an astable oscillator (components 1 , 2, 5, 7, 9, 10), which in turn comprises a capacitance (between sensor electrode 1 and target 2) connected via a shielded connecting cable 5, 7 to remotely located oscillator/driver components 9, 10 which include a resistance 9 and a switching circuit 10 (an inverting Schmitt trigger is illustrated).
  • the driver circuit also includes a parasitic capacitance suppression circuit 3, 4, 6, 8, comprising high-precision voltage follower 8, intermediate cable shielding 6, guard electrode 4 and dielectric 3.
  • the voltage follower 8 having a very high input impedance but very low output impedance, serves to drive the
  • the free-running oscillation frequency of the astable oscillator circuit is determined by the value of the (constant) resistance 9 and the (possibly varying) capacitance between the sensor electrode 1 and the target 2.
  • All the components which make up the astable oscillator circuit are located at one end (the driver end) of the sensor connector cable 5, 6, 7 - all except the capacitive sensor electrode 1 , that is. Similarly, all the components which make up the parasitic capacitance suppression circuit - all except the guard electrode 4 and dielectric 3, that is - are located at the driver end of the sensor connector cable 5, 6, 7. This allows the sensor electrode assembly 1 , 3, 4 to be made small and/or thin, and remote from the driver electronics, so that it can be used in inaccessible areas of machinery etc.
  • the sensor connector cable 5, 6, 7 may in principle be any type of shielded cable, but it has been found advantageous to use a triaxial cable, for example with the sensor electrode 1 connected to the inner connector 7, the guard electrode 4 connected to the inner shielding layer 6, and the outer shielding layer 5 connected to ground (for example grounded to the surrounding machinery).
  • the target 2 may be a metallic surface which is substantially parallel to the electrode surface, and it may be grounded (as illustrated) with a ground plane common to the ground of the sensor driver circuit.
  • the capacitive sensor may also be used in conditions where the target is non-metallic, non-conducting or not grounded, or grounded to a different ground plane than the driver circuit. Under such conditions, local changes in the local dielectric, or the close presence of a conductor, can nevertheless result in a measurable change in capacitive parameters of the sensor 1 , 3, 4.
  • the astable oscillator is shown in the example of figure 1 as comprising a bistable switching element (inverting Schmitt trigger 10), a resistance 9 and the capacitive sensor electrode assembly 1 , 3, 4.
  • Other suitable components could be used for implementing the switching part of the oscillator, but the inverting Schmitt trigger has been chosen in this example because it is a simple and easily-available component with stable operating characteristics.
  • a high-precision voltage follower circuit 8 allows the voltage on the resistance 9 to be applied accurately to the guard electrode 4 via the inner shielding connector 6 of the triaxial cable, thereby compensating for any impedance change affecting the phase of the guard signal.
  • Galvanic separation may be achieved for example by means of an optical signal connection to processing circuit 12.
  • an inductive sensor could be used, arranged as part of an LR resonant circuit, with appropriate amendments to the remaining circuitry to take account of the different voltage/current phase relationship which pertain in an inductive sensor.

Landscapes

  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Measurement Of Length, Angles, Or The Like Using Electric Or Magnetic Means (AREA)

Abstract

La présente invention concerne un dispositif de mesure de petites distances pour la mesure sans contact d'entrefer. Le dispositif comporte un ensemble d'électrodes de capteur capacitif (1, 3, 4) pour détecter des variations dans la capacité entre une électrode de capteur (1) et une cible (2). Le dispositif comporte un oscillateur astable (1, 2, 5, 7, 9, 10) comprenant une bascule de Schmitt (10), la fréquence d'oscillation étant déterminée par une capacité au niveau de l'électrode de capteur (1) et une résistance constante de temps (9). Les composants de l'oscillateur astable (1, 2, 5, 7, 9, 10), à l'exception du capteur d'électrode, sont situés à distance de l'ensemble de capteur d'électrode (1, 3, 4) et connectés à l'ensemble d'électrodes de capteurs (1, 3, 4) par un câble triaxial (5, 6, 7). La sortie de l'oscillateur astable peut faire l'objet d'une séparation galvanique par rapport à des circuits de traitement ultérieurs, tel qu'un circuit démodulateur de fréquence (12). La séparation galvanique peut être réalisée au moyen d'un connecteur optique (11).
PCT/EP2012/076957 2012-12-27 2012-12-27 Circuit d'attaque pour capteur capacitif d'entrefer WO2014101943A1 (fr)

Priority Applications (1)

Application Number Priority Date Filing Date Title
PCT/EP2012/076957 WO2014101943A1 (fr) 2012-12-27 2012-12-27 Circuit d'attaque pour capteur capacitif d'entrefer

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
PCT/EP2012/076957 WO2014101943A1 (fr) 2012-12-27 2012-12-27 Circuit d'attaque pour capteur capacitif d'entrefer

Publications (1)

Publication Number Publication Date
WO2014101943A1 true WO2014101943A1 (fr) 2014-07-03

Family

ID=47563390

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/EP2012/076957 WO2014101943A1 (fr) 2012-12-27 2012-12-27 Circuit d'attaque pour capteur capacitif d'entrefer

Country Status (1)

Country Link
WO (1) WO2014101943A1 (fr)

Cited By (11)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2016043696A1 (fr) * 2014-09-15 2016-03-24 Church David C Système chirurgical comprenant un élément amovible et un circuit de détection d'état pour la détection d'état de fixation d'élément amovible
US9387050B2 (en) 2014-09-15 2016-07-12 Gyrus Acmi Inc. Surgical system having detachable component and state detection circuit for detection of state of attachment of detachable component
US20160259411A1 (en) * 2015-03-08 2016-09-08 Apple Inc. Gap Sensor for Haptic Feedback Assembly
US9726922B1 (en) 2013-12-20 2017-08-08 Apple Inc. Reducing display noise in an electronic device
WO2017202564A1 (fr) * 2016-05-25 2017-11-30 Fogale Nanotech Dispositif de detection capacitive a garde nulle
US9927905B2 (en) 2015-08-19 2018-03-27 Apple Inc. Force touch button emulation
EP3434426A1 (fr) * 2017-07-26 2019-01-30 Fogale Nanotech Robot muni de moyens de détection capacitifs et d'organe(s) référencé(s) à un potentiel de garde
EP3434427A1 (fr) * 2017-07-26 2019-01-30 Fogale Nanotech Robot muni de moyens de détection capacitifs et de parois référencées à un potentiel de garde
US10282014B2 (en) 2013-09-30 2019-05-07 Apple Inc. Operating multiple functions in a display of an electronic device
US10296123B2 (en) 2015-03-06 2019-05-21 Apple Inc. Reducing noise in a force signal in an electronic device
US10416811B2 (en) 2015-09-24 2019-09-17 Apple Inc. Automatic field calibration of force input sensors

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2071852A (en) * 1980-03-12 1981-09-23 Rolls Royce Capacitance frequency modulation probe for blade tip clearance measurement
US20020140440A1 (en) 2001-02-02 2002-10-03 Haase Wayne C. Digital measurement circuit and system using a grounded capacitive sensor
US6552667B1 (en) * 2000-11-16 2003-04-22 Hydro-Quebec Non-contact measuring method and apparatus for producing a signal representative of a distance between facing surfaces
CH696895A5 (fr) 2003-04-11 2008-01-15 Mc Monitoring S A Dispositif de mesure d'une capacité variable à circuit de mesure résonant.
FR2976724A1 (fr) * 2011-06-16 2012-12-21 Nanotec Solution Dispositif pour generer une difference de tension alternative entre des potentiels de reference de systemes electroniques.

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2071852A (en) * 1980-03-12 1981-09-23 Rolls Royce Capacitance frequency modulation probe for blade tip clearance measurement
US6552667B1 (en) * 2000-11-16 2003-04-22 Hydro-Quebec Non-contact measuring method and apparatus for producing a signal representative of a distance between facing surfaces
US20020140440A1 (en) 2001-02-02 2002-10-03 Haase Wayne C. Digital measurement circuit and system using a grounded capacitive sensor
CH696895A5 (fr) 2003-04-11 2008-01-15 Mc Monitoring S A Dispositif de mesure d'une capacité variable à circuit de mesure résonant.
FR2976724A1 (fr) * 2011-06-16 2012-12-21 Nanotec Solution Dispositif pour generer une difference de tension alternative entre des potentiels de reference de systemes electroniques.

Cited By (29)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US10282014B2 (en) 2013-09-30 2019-05-07 Apple Inc. Operating multiple functions in a display of an electronic device
US9726922B1 (en) 2013-12-20 2017-08-08 Apple Inc. Reducing display noise in an electronic device
US10394359B2 (en) 2013-12-20 2019-08-27 Apple Inc. Reducing display noise in an electronic device
EP3936067A1 (fr) * 2014-09-15 2022-01-12 Gyrus ACMI, Inc. (D.B.A. Olympus Surgical Technologies America) Système chirurgical comprenant un élément amovible
EP3193760A4 (fr) * 2014-09-15 2018-05-02 Gyrus ACMI, Inc. (d.b.a.Olympus Surgical Technologies America) Système chirurgical comprenant un élément amovible et un circuit de détection d'état pour la détection d'état de fixation d'élément amovible
US9681885B2 (en) 2014-09-15 2017-06-20 Gyrus Acmi Inc. Surgical system having detachable component and state detection circuit for detection of state of attachment of detachable component
CN106999230B (zh) * 2014-09-15 2019-08-16 吉拉斯Acmi股份有限公司（经营名称为奥林巴斯外科技术美国公司） 具有可拆卸组件和用于检测可拆卸组件的附连状态的状态检测电路的外科手术系统
WO2016043696A1 (fr) * 2014-09-15 2016-03-24 Church David C Système chirurgical comprenant un élément amovible et un circuit de détection d'état pour la détection d'état de fixation d'élément amovible
US9387050B2 (en) 2014-09-15 2016-07-12 Gyrus Acmi Inc. Surgical system having detachable component and state detection circuit for detection of state of attachment of detachable component
CN106999230A (zh) * 2014-09-15 2017-08-01 吉拉斯Acmi股份有限公司（经营名称为奥林巴斯外科技术美国公司） 具有可拆卸组件和用于检测可拆卸组件的附连状态的状态检测电路的外科手术系统
US10296123B2 (en) 2015-03-06 2019-05-21 Apple Inc. Reducing noise in a force signal in an electronic device
US10185397B2 (en) * 2015-03-08 2019-01-22 Apple Inc. Gap sensor for haptic feedback assembly
CN107209569B (zh) * 2015-03-08 2020-07-28 苹果公司 用于触觉反馈组件的间隙传感器
US20160259411A1 (en) * 2015-03-08 2016-09-08 Apple Inc. Gap Sensor for Haptic Feedback Assembly
CN107209569A (zh) * 2015-03-08 2017-09-26 苹果公司 用于触觉反馈组件的间隙传感器
US9927905B2 (en) 2015-08-19 2018-03-27 Apple Inc. Force touch button emulation
US10416811B2 (en) 2015-09-24 2019-09-17 Apple Inc. Automatic field calibration of force input sensors
WO2017202564A1 (fr) * 2016-05-25 2017-11-30 Fogale Nanotech Dispositif de detection capacitive a garde nulle
FR3051896A1 (fr) * 2016-05-25 2017-12-01 Fogale Nanotech Dispositif de detection capacitive a garde nulle
KR20190022437A (ko) * 2017-07-26 2019-03-06 포걀 나노떼끄 가드 전위를 기준으로 하는 항목(들) 및 용량성 감지 수단이 구비된 로봇
KR20190022438A (ko) * 2017-07-26 2019-03-06 포걀 나노떼끄 가드 전위를 기준으로 하는 벽들 및 용량성 감지 수단이 구비된 로봇
WO2019020874A1 (fr) * 2017-07-26 2019-01-31 Fogale Nanotech Robot muni de moyens de detection capacitifs et d'organe(s) reference(s) a un potentiel de garde
WO2019020873A1 (fr) * 2017-07-26 2019-01-31 Fogale Nanotech Robot muni de moyens de detection capacitifs et de parois referencees a un potentiel de garde
EP3434427A1 (fr) * 2017-07-26 2019-01-30 Fogale Nanotech Robot muni de moyens de détection capacitifs et de parois référencées à un potentiel de garde
KR102058809B1 (ko) 2017-07-26 2020-02-07 포걀 나노떼끄 가드 전위를 기준으로 하는 벽들 및 용량성 감지 수단이 구비된 로봇
KR102058808B1 (ko) 2017-07-26 2020-02-20 포걀 나노떼끄 가드 전위를 기준으로 하는 부품(들) 및 용량성 감지 수단이 구비된 로봇
US10710252B2 (en) 2017-07-26 2020-07-14 Fogale Nanotech Robot equipped with capacitive detection means and item(s) referenced to a guard potential
EP3434426A1 (fr) * 2017-07-26 2019-01-30 Fogale Nanotech Robot muni de moyens de détection capacitifs et d'organe(s) référencé(s) à un potentiel de garde
US11052546B2 (en) 2017-07-26 2021-07-06 Fogale Nanotech Robot equipped with capacitive detection means and walls referenced to a guard potential

Similar Documents

Publication Publication Date Title
WO2014101943A1 (fr) Circuit d'attaque pour capteur capacitif d'entrefer
KR0166981B1 (ko) 용량성 센서를 사용하여 변위 혹은 유전율의 동적 및 비접촉 측정을 하는 방법
US4067225A (en) Capacitance type non-contact displacement and vibration measuring device and method of maintaining calibration
CN102057250B (zh) 漂移补偿的惯性旋转传感器
RU2686522C2 (ru) Способ мониторинга в режиме реального времени рабочего состояния емкостного датчика
CN106415190B (zh) 用于感测轴的位置或运动的方法、传感器以及印刷电路板
KR101903914B1 (ko) 박막 기반 자력계
US9846024B1 (en) Solid-state electric-field sensor
KR20160109121A (ko) 주파수 변조를 이용한 인덕턴스 방식의 변위센서
CN107923767B (zh) 用于确定传感器线圈电感的方法和装置
US11828628B2 (en) Position sensing apparatus with remote electronics for harsh environments
WO2014141745A1 (fr) Dispositif de mesure et unité de montage
EP2592753A2 (fr) Ensemble de capteur de proximité et système d'inspection
US10856452B1 (en) Sensor apparatus
Wang et al. A universal high-sensitivity area-variation capacitive displacement transducer (CDT) based on fringe effect
SE1050526A1 (sv) Spole innefattande lindning bestående av en multi-axialkabel
US20150042343A1 (en) Object finder
CN108027292A (zh) 包括压力传感器的用于测量的设备以及用于测量压力的系统
Moore et al. Simultaneous actuation and sensing for electrostatic drives in MEMS using frequency modulated capacitive sensing
CN110849255B (zh) 一种位移传感器
US20230175869A1 (en) Position sensing apparatus having internal target rod with remote electronics for harsh environments
EP1334328B1 (fr) Procede de mesure sans contact et dispositif servant a produire un signal representatif d'une distance separant des surfaces opposees
US4874252A (en) Electronic thermometer
EP2592391A2 (fr) Élément de détection pour ensemble capteur
KR19990016272A (ko) 2축 동시 측정용 압전 회전 센서 및 그 측정 회로

Legal Events

Date Code Title Description
121 Ep: the epo has been informed by wipo that ep was designated in this application

Ref document number: 12816304

Country of ref document: EP

Kind code of ref document: A1

NENP Non-entry into the national phase

Ref country code: DE

122 Ep: pct application non-entry in european phase

Ref document number: 12816304

Country of ref document: EP

Kind code of ref document: A1