EP1521972A1 - Capteur thermique pour detecter une acceleration ou un choc, comportant une unite de chauffage, et procede associe - Google Patents

Capteur thermique pour detecter une acceleration ou un choc, comportant une unite de chauffage, et procede associe

Info

Publication number
EP1521972A1
EP1521972A1 EP03709632A EP03709632A EP1521972A1 EP 1521972 A1 EP1521972 A1 EP 1521972A1 EP 03709632 A EP03709632 A EP 03709632A EP 03709632 A EP03709632 A EP 03709632A EP 1521972 A1 EP1521972 A1 EP 1521972A1
Authority
EP
European Patent Office
Prior art keywords
heating device
sensor
temperature
fluid
heating
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Withdrawn
Application number
EP03709632A
Other languages
German (de)
English (en)
Inventor
Michael Arndt
Isolde Simon
Bernhard Jakoby
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.)
Robert Bosch GmbH
Original Assignee
Robert Bosch GmbH
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 Robert Bosch GmbH filed Critical Robert Bosch GmbH
Publication of EP1521972A1 publication Critical patent/EP1521972A1/fr
Withdrawn legal-status Critical Current

Links

Classifications

    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01P—MEASURING LINEAR OR ANGULAR SPEED, ACCELERATION, DECELERATION, OR SHOCK; INDICATING PRESENCE, ABSENCE, OR DIRECTION, OF MOVEMENT
    • G01P15/00—Measuring acceleration; Measuring deceleration; Measuring shock, i.e. sudden change of acceleration
    • G01P15/02—Measuring acceleration; Measuring deceleration; Measuring shock, i.e. sudden change of acceleration by making use of inertia forces using solid seismic masses
    • G01P15/08—Measuring acceleration; Measuring deceleration; Measuring shock, i.e. sudden change of acceleration by making use of inertia forces using solid seismic masses with conversion into electric or magnetic values
    • G01P15/12—Measuring acceleration; Measuring deceleration; Measuring shock, i.e. sudden change of acceleration by making use of inertia forces using solid seismic masses with conversion into electric or magnetic values by alteration of electrical resistance
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01P—MEASURING LINEAR OR ANGULAR SPEED, ACCELERATION, DECELERATION, OR SHOCK; INDICATING PRESENCE, ABSENCE, OR DIRECTION, OF MOVEMENT
    • G01P15/00—Measuring acceleration; Measuring deceleration; Measuring shock, i.e. sudden change of acceleration
    • G01P15/006—Measuring acceleration; Measuring deceleration; Measuring shock, i.e. sudden change of acceleration by making use of fluid seismic masses
    • G01P15/008—Measuring acceleration; Measuring deceleration; Measuring shock, i.e. sudden change of acceleration by making use of fluid seismic masses by using thermal pick-up
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01P—MEASURING LINEAR OR ANGULAR SPEED, ACCELERATION, DECELERATION, OR SHOCK; INDICATING PRESENCE, ABSENCE, OR DIRECTION, OF MOVEMENT
    • G01P15/00—Measuring acceleration; Measuring deceleration; Measuring shock, i.e. sudden change of acceleration
    • G01P15/18—Measuring acceleration; Measuring deceleration; Measuring shock, i.e. sudden change of acceleration in two or more dimensions
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B60—VEHICLES IN GENERAL
    • B60R—VEHICLES, VEHICLE FITTINGS, OR VEHICLE PARTS, NOT OTHERWISE PROVIDED FOR
    • B60R21/00—Arrangements or fittings on vehicles for protecting or preventing injuries to occupants or pedestrians in case of accidents or other traffic risks
    • B60R21/01—Electrical circuits for triggering passive safety arrangements, e.g. airbags, safety belt tighteners, in case of vehicle accidents or impending vehicle accidents
    • B60R21/013—Electrical circuits for triggering passive safety arrangements, e.g. airbags, safety belt tighteners, in case of vehicle accidents or impending vehicle accidents including means for detecting collisions, impending collisions or roll-over

Definitions

  • the invention is based on a sensor with a heating device and a method according to the type of the independent claims.
  • acceleration sensors mounted in particular in vehicles are used today. These mostly evaluate the movement of a seismic mass.
  • sensors based on thermal functional principles are also known.
  • such a known sensor has a trench, over which bridges are freely suspended in the transverse direction.
  • One of these bridges is used as a heating element, while two adjacent bridges act as temperature sensors. Starting with the heating element, the heating creates a temperature gradient in the direction of the temperature sensors. A sudden acceleration of the sensor changes the temperature gradient.
  • thermal acceleration sensors are relatively robust since, in contrast to sensors with a seismic mass, they do not comprise any moving parts.
  • the fine, freely suspended bridges severely limit this robustness. They are particularly vulnerable to the area around the free-hanging bridges, i.e. H. for example, particles in the air. Furthermore, they are expensive to manufacture because z. B. a conventional sawing process with these sensors is not or only very difficult to carry out.
  • the sensor according to the invention and the method according to the invention with the features of the independent claims have the advantage that a simpler, more robust sensor and. an evaluation method or a method for measurement are proposed. It is also advantageous that the heating device and the temperature measuring means are provided at the same location or in the immediate vicinity of one another. This increases the stability or the robustness of the sensor arrangement.
  • the output signal does not depend on the inclination of the sensor.
  • the output signal is independent of the direction in which the acceleration takes place.
  • the electrical resistance of the heating device and a sonication of the heating device are provided as the temperature measuring means. It is thus possible according to the invention to carry out both the heating function and the temperature measurement function by the heating device. As a result, the sensor arrangement according to the invention is simpler and cheaper to manufacture and is therefore more robust to provide at the same price.
  • the heating device is provided for operation with a constant current or a constant voltage or a constant power, the current or the voltage or the power being provided in particular as a function of a signal from an ambient temperature sensor, with the result that the sensor arrangement according to the invention can be designed such that it can be used to compensate for the sensitivity to measurement over a wide ambient temperature range.
  • thermocouple is provided at the location of the heating device or in its immediate vicinity. This makes it possible to provide a measurement of the temperature of the fluid that is independent of the electrical resistance of the heating device.
  • a plurality of heating devices and a plurality of temperature measuring means are provided. This makes it possible to use the Comparison of the temporal course of the temperatures measured with the temperature measuring means to conclude the direction of impact.
  • an arrangement of the plurality of heating devices and their sound system in the form of a Wheatstone bridge an increased output signal can also be achieved in a variant of the sensor arrangement according to the invention.
  • FIG. 1 shows a known sensor arrangement according to the prior art
  • FIG. 2 shows a first embodiment of the sensor arrangement according to the invention in a perspective illustration and in a sectional illustration
  • FIG. 3 shows the sensor arrangement according to the invention with a first variant of the
  • Figure 4 shows the sensor arrangement according to the invention with a second variant of the
  • FIG. 5 shows a second embodiment of the sensor arrangement according to the invention in
  • Figure 6 shows a third embodiment of the sensor arrangement according to the invention.
  • FIG. 7 shows a block diagram of evaluation electronics for the first embodiment of the sensor arrangement according to the invention
  • FIG. 8 shows a possible implementation of part of the evaluation circuit
  • FIG. 9 shows a block diagram of evaluation electronics for the second embodiment of the sensor arrangement according to the invention.
  • FIG. 10 shows a block diagram of an evaluation electronics for the third embodiment of the sensor arrangement according to the invention.
  • FIG. 11 shows a representation as a function of the time of the useful signal of the sensor arrangement according to the invention in the event of a lighter impact
  • Figure 12 is a representation in function of time of the useful signal of the present invention SensoranOrduun 'g bereinem heavier impact _ ⁇
  • FIG. 13 shows a further variant of the sensor arrangement according to the invention
  • FIG. 14 shows a fourth embodiment of the sensor arrangement according to the invention.
  • FIG. 15 shows a fifth embodiment of the sensor arrangement according to the invention
  • FIG. 17 shows a block diagram of evaluation electronics for the fifth embodiment of the sensor arrangement according to the invention.
  • FIG. 1 a known sensor for detecting a shock, for. B. upon impact of an object on a motor vehicle, according to the prior art.
  • the sensor according to the prior art is provided with the reference symbol 100.
  • the sensor 100 comprises a trench 120, over which extremely fine, freely suspended bridges are stretched in the transverse direction. These are designated by reference numerals 130 and 140 in FIG. 1.
  • One of these bridges is used as a heating element 130, while the adjacent bridges 140 act as temperature sensors. Starting from the heating element 130, the heating forms a temperature gradient in the direction of the temperature sensors in the surrounding fluid.
  • a sudden acceleration of the sensor for example due to a shock, causes a change in the temperature gradient. This change is detected via the temperature sensors 140 and converted into an output signal proportional to the acceleration by means of evaluation electronics.
  • a disadvantage of this arrangement is that the fine, freely suspended bridges 130, 140 are not very robust. These bridges are susceptible to particles in the air or in the medium surrounding the bridges. In addition, they are expensive to manufacture because z. B. a conventional sawing process cannot be carried out with these sensors.
  • a sensor 1 according to the invention or a sensor arrangement 1 according to the invention is shown in a perspective representation in the upper part of the figure and in a sectional representation in the lower part of the figure.
  • the sensor 1 is implemented in a substrate 10, which is provided in particular as a semiconductor substrate 10.
  • the substrate 10 is also referred to below as the silicon substrate 10.
  • another semiconductor material can also be used as a substrate or also serve as a substrate material that is not a semiconductor.
  • a cavern 20 is provided in the substrate 10 of the sensor " T " , " which can only be seen in the sectional view in the lower part of the figure in Figure 2.
  • the cavern 20 can be produced, for example, from the back of the substrate 10 using bull cr-mechanical technology.
  • a membrane 25 remains on the front side of the substrate 10.
  • the formation of the cavern 20 takes place according to the invention in particular by etching the cavern 20 into the silicon substrate 10.
  • the cavern 20 is on the front side of the substrate 10 Completed by the membrane 25, which has dielectric properties and has a thermally insulating effect, there is at least one temperature-dependent resistor 30, for example made of platinum, on the membrane 25.
  • the temperature-dependent resistor 30 in addition to the temperature-dependent resistor 30 further resistances or a Thermocouple are provided on the membrane 25.
  • the membrane 25 with the structures thereon has a low thermal mass and thus has a low thermal time constant. It is thus possible to provide sensor arrangements 1 which have a time constant in the range from 1 millisecond to 15 milliseconds.
  • the resistor 30 or, in the case of a plurality of resistors, at least one of these resistors is electrically heated. If the sensor 1 is at rest, ie no acceleration forces are acting on the sensor, a narrowly limited volume of heated gas, for example air, or a conventional flow of gas forms above and below the electrically heated resistor 30. The temperature of the resistor 30 and thus its resistance value is set to a constant value.
  • the inertia of the cold air in the vicinity of the mentioned air volume or, in general, the fluid volume causes the heated volume to move away from the sensor , ie in this case moved away from the location of the temperature measurement. Because of the low time constant of the membrane 25, the resistor 30 cools down accordingly. This leads to a change in the resistance value of the resistor 30, which can be detected with an evaluation device or evaluation electronics.
  • the evaluation electronics comprise means for heating the resistor 30 and means for measuring the resistance value of the resistor 30 and for converting the same into an electrical useful signal.
  • the sensor 1 and the evaluation electronics can be used for the detection of suddenly occurring impacts.
  • the signal amplitude of the useful signal depends on the strength of the Shock dependent. Therefore, the sensor 1 can also be used for an acceleration measurement. According to the invention, it is useful if the deflection amplitude of the impact is sufficiently large, for example a few millimeters, so that the resistor 30 can move below the gas volume mentioned and thus “see” a different temperature. However, it is also clear that the minimum amplitude of the shock with respect to the distance of the deflection will be smaller, the smaller the dimensions of the resistor 30 or the cavern 20 and the entire sensor arrangement 1.
  • the sensor arrangement 1 according to the invention has a robust structure and can be manufactured using standard methods. Since cores seismic masses are needed that • can beat in a strong shock to a stop, it is possible that with such an inventive sensor large impact intensity ranges can be measured without potential damage to sensitive moving parts in the sensor first
  • the sensor 1 is based on the principle that the resistor 30 is provided as a heating device 30.
  • the heating device 30 is in thermal contact with a fluid, in particular a gas, which is located in the cavern 20 or also on the top of the membrane 25. Without the influence of an accelerating force acting on the sensor 1, the heating effect of the heating device 30 forms a thermal equilibrium in the form of a constant heat flow from the heating device 30 into the fluid. If the sensor arrangement 1 together with its heating device 30 is subjected to an accelerating force, the inertia of the fluid causes the fluid to move relative to the heating device 30, as a result of which the thermal equilibrium is changed, which leads to a temperature change at the location of the heating device or in leads to their immediate proximity.
  • a temperature measuring means is provided at the location of the heating device 30 or in its immediate vicinity, which can detect the change in the thermal equilibrium by means of a temperature change. The movement of the fluid relative to the heating device 30 can thereby be measured.
  • the electrical resistance value of the heating device 30 serves as a temperature measuring means.
  • a temperature control means separate from the heating device 30 is provided.
  • the formation of the membrane 25 in silicon oxide and silicon nitride is particularly useful according to the invention when using silicon substrate as substrate 10.
  • FIG. 3 shows a first variant of the shape of the heating device 30 in a meandering shape
  • FIG. 4 shows a second variant of the shape of the heating device 30 in a helical shape.
  • the resistance device 30 or the heating device 30 can be electrically connected to connection areas and bond pads (reference number 36) and leads 35.
  • the bond pads 36 and the leads 35 are provided on the substrate 10.
  • the resistance device 30 is provided in particular made of platinum.
  • FIG. 5 shows a second embodiment of the sensor 1 according to the invention.
  • an ambient temperature sensor 50 is provided on the substrate 10, which can also be connected by means of bond pads and supply lines, which, however, are not identified by reference numerals.
  • the ambient temperature sensor 50 the invention provides in particular also ⁇ of platinum.
  • the ambient temperature sensor 50 is provided for the detection of the ambient temperature.
  • the resistance value of the ambient temperature sensor can be used for the compensation of the measuring sensitivity of the temperature measuring means according to the invention over a wide ambient temperature range.
  • FIG. 6 shows a third embodiment of the sensor arrangement 1 according to the invention.
  • a thermal element 31 separate from the heating device 30 is now provided, which measures the temperature of the fluid at the location of the heating device or in its immediate vicinity.
  • the ⁇ noelement 31 is designed as a temperature sensor and connected by means of special leads 311 on the substrate 10 with bond pads, not designated by reference numerals. According to the invention, it is provided in the third embodiment that the thermo element 31 is provided directly at the location of the heating device 30 or in its immediate vicinity.
  • the location of the heating device 30 is understood here - in the case of a meandering film of the heating device 30 on the membrane 25 - to mean the entire membrane area which is more or less covered by the meandering structure of the heating device 30. Even if the thermocouple 31 in addition to a resistance line of the heating element 30 but inside a loop of the meandering structure of the heating device 30 is provided, the thermo element 31 is nevertheless arranged at the location of the heating device 30, since no better one is used when the heating device 30 is used as the temperature means. Spatial resolution with regard to temperature detection would be possible.
  • the thermo element 31 comprises a hot connection at its tip (letter A in FIG. 6) and a cold connection at its connection to the supply lines 311 (letter B in FIG . 6).
  • a thermocouple usually consists of two connections between two electrically conductive or semiconducting materials. A supply line leads to each of these connections. An electrical voltage can be measured between the ends of these leads as soon as a temperature difference between the two connection points occurs. Usually the hot one is then. Connection at a higher temperature than the cold connection. In the sensor described here, the hot connection is therefore on the heated membrane and the cold connection on the surrounding substrate.
  • FIG. 7 shows a block diagram of the evaluation electronics for the first embodiment of the sensor 1 according to the invention.
  • the heating resistor provided as heating device 30 on membrane 25 is operated with a constant current or a constant voltage or a constant output. This is shown in FIG. 7 for the case of a constant current.
  • the heating current is designated by the reference symbol 300 in FIG.
  • the resistance value of the heating device 30 is designated in FIG. 7 with the reference symbol 310.
  • a constant current source 301 is provided to generate the constant heating current 300.
  • the heating resistor 310 is measured by means of a voltage drop across it and fed to an amplifier circuit 60.
  • an offset correction is carried out in an offset correlation device 65 by means of an offset correction voltage 650 and the signal is then filtered in a filter device 70.
  • the useful signal 700 can then be extracted from the filter device 70 in relation to the mass 698.
  • FIG. 8 shows a possible implementation of the evaluation circuit from FIG. 7, but the filter device 70 has been dispensed with.
  • a first one Operational amplifier 330 which is connected to supply voltage 699 and ground potential 698, serves to set the constant heating current 300 through heating resistor 310, which is connected between the output of first operational amplifier 330 and its inverting input.
  • the non-inverting input of the first operational amplifier is connected to the tap of a first controllable resistor 320, which is used to set the heating current 300.
  • a first resistor 305 is arranged between ground 698 and the inverting input of the first operational amplifier 330.
  • the output signal 315 of the first operational amplifier 330 is amplified by means of a second operational amplifier 651 and offset-compensated.
  • the output of the first operational amplifier 330 is connected to the inverting input of the second operational amplifier 651 via a second resistor 306.
  • the output of the second operational amplifier 651 is further connected to the inverting input of the second operational amplifier 651 by means of a third resistor 658.
  • the second operational amplifier 651 thus serves as an amplification device 60.
  • a second controllable resistor 655 lies between the supply voltage 699 and the ground potential 698, the tap of the second controllable resistor 655 being connected via a fourth resistor 656 to the non-inverting input of the second operational amplifier 651 , Furthermore, the non-inverting.
  • the input of the second operational amplifier 651 is connected to the ground potential 698 via a fifth resistor 657.
  • the described arrangement at the non-inverting input of the second operational amplifier 651 carries out an offset compensation.
  • the second operational amplifier 651 also partially corresponds to the offset compensation device 65 from FIG. 7.
  • the (unfiltered) useful signal 700 can be tapped at the output of the second operational amplifier 651.
  • FIGS. 11 and 12 show representations of the time profile of the useful signal 700 at the output of an evaluation circuit according to FIG. 8 in the event that an impact is exerted on the sensor arrangement 1 in the middle of the time profile shown.
  • the signal shown in FIG. 11 is the signal for a lighter impact and the signal shown in FIG. 12 is the signal for a heavier impact.
  • FIG. 9 shows a block diagram of evaluation electronics for the second embodiment of the sensor arrangement 1 according to the invention.
  • the Evaluation electronics for the second embodiment of the sensor arrangement according to the invention comprises an amplification device 60, an offset compensation device 65, although the offset compensation voltage 650 was not shown in FIG. 9 for the sake of simplicity, and a filter device 70, at the output of which the useful signal 700 is compared to the Mass 698 is present.
  • the heating current 300 is regulated by the heating device 30 as a function of the ambient temperature.
  • the ambient temperature sensor 50 is provided, which in FIG.
  • control signal 320 is fed to a heating current control device 32, which controls the heating current 300 through the heating device 30 as a function of the control signal 320.
  • the control signal 320 acts in particular on the controllable constant current source 301.
  • the control signal 320 is a signal generated by the transducer and the ambient temperature sensor, which adjusts the heating of the sensor element in such a way that the shock sensitivity remains the same over a wide range of ambient temperatures.
  • the heating current 300 is still constant with regard to the time scales relevant to the detection of the movement state of the sensor arrangement 1, even if it is regulated as a function of the ambient temperature.
  • the fact is that the time constants for changing the ambient temperature and thus also the time constants for setting or changing the heating current 300 are much longer or larger than the time constants for detecting a movement of the fluid relative to the heating element 30 according to the invention.
  • the heating current 300 can therefore also be regarded as constant in the second embodiment of the invention with regard to the measurement of the movement of the fluid.
  • FIG. 10 shows evaluation electronics for use with the third embodiment of the sensor arrangement according to the invention.
  • the heating current 300 in turn flows through the heating device 30 and the resistance value 310 of the heating device 30 is dependent on the temperature of the fluid. Due to the galvanic separation between the heating device 30 and the temperature means in the form of a thermo element 31, the evaluation electronics according to the third embodiment serve as the input sensor arrangement according to the invention, the temperature signal 315 which is amplified in an amplifier device 60, is offset in an offset compensation device 65 by means of an offset compensation voltage 650 offset and is filtered in a filter device 70 in order to generate the useful signal 700.
  • the transmitter so that the heating device 30, or alternatively a constant voltage or a constant power is operated with a constant heating current 300 respectively.
  • the ⁇ noelement 31 always provides a temperature dependent voltage '315 315 as a temperature signal for generating the output signal 700 and the desired signal 700, the temperature dependent voltage 315 is amplified, offset ko ⁇ i yaws and filtered.
  • FIG. 13 shows a further construction variant of the sensor arrangement 1 according to the invention in a perspective view.
  • a cavern 20 is provided in a substrate 10, a heating device 30 being in thermal contact with the fluid in particular located in the cavern 20.
  • a membrane between the heating device 30 and the cavern is not provided in the further construction variant of the sensor arrangement 1 according to the invention.
  • the sensor 1 can thus also consist of a substrate 10 or silicon substrate 10, into which the cavern 20 is etched in such a way that a temperature-dependent resistor remains suspended above the cavern 20 as a heating device 30 in a meandering or snail shape.
  • FIG. 13 shows a bond pad 36 and a feed line 35 for the heating device 30.
  • FIG. 14 shows a fourth embodiment of the sensor arrangement 1 according to the invention, a substrate 10 and a membrane 25 again being provided, a plurality of heating devices 30, 29, 28, 27 being provided on the membrane 25 in the fourth embodiment of the sensor arrangement 1 according to the invention are.
  • Each of the heating devices 27 to 30 each has two bond pads and corresponding leads for their electrical ⁇ ⁇ connection. This is illustrated for the first heating device 30 by way of example using the bond pad 36 and the connecting line 35 in FIG. 14.
  • it is possible to infer the direction of impact by comparing the time profile of the resistance values of the heating device 27 to 30.
  • each of the heating elements 27 to 30 are connected to evaluation electronics according to the first or second embodiment. Then the impact direction and the impact intensity can be measured on the basis of the temporal position of the signals of the different heating devices 27 to 30 and their amplitudes.
  • FIG. 16 shows, by way of example, four representations of the time profile of the useful signals of the evaluation electronics assigned to the heating devices 27 to 30 but not shown.
  • the useful signal 700 of the heating device 30 is shown in the first representation.
  • the useful signal 729 of the first further heating device 29 is shown.
  • the useful signal 728 of the second further heating device 28 is shown.
  • the useful signal 727 of the third further heating device 27 is shown.
  • the signals shown in FIG. 16 correspond in principle to the signals shown in FIGS. 11 and 12, but the sign has been changed.
  • the signals 700, 729, 728, 727 have a certain time interval in this order.
  • the signals 700 and 729 are of a larger amplitude than the signals 728 and 727. From the temporal position of the signals 700, 729, 728, 727 relative to one another and the pulse height or the signal amplitude, the direction of impact and the intensity of the impact can be concluded.
  • FIG. 15 shows a fifth embodiment of the sensor assembly 1 according to the invention.
  • the heating device 30 and the first further heating device 29 are provided on the membrane 25, each of which can be electrically connected by means of lines and bond pads, which is explicitly shown in FIG. 15 for the example of the heating device 30 and the associated connecting line 35 or the associated bonding pad 36 ,
  • the heating device 30 and the first further heating device 29 represent two thermally closely coupled heating resistors which are almost always at the same temperature. If these are arranged in the opposite branches of a Wlieatstone bridge, an increased measurement signal can be generated, which can be amplified with an amplifier.
  • FIG. 17 shows evaluation electronics for the fifth embodiment of the sensor arrangement according to the invention.
  • the resistance value of the heating device 30 is provided with the reference symbol 310 and the resistance value of the first further heating device 29 is provided with the reference symbol 290. Together with a seventh resistor 294 and a third controllable resistor 295, the two resistance values 310, 290 of the heating devices 30, 29 form a Wheatstone bridge, the tap lying between the third controllable resistor 295 and the resistance value 310 being fed to the inverting input of a third operational amplifier 602 and the tapping of the Wheatstone bridge located between the resistance value 290 of the first further heating device 29 and the seventh resistor 294 is led to the non-inverting input of the third operational amplifier 602.
  • the third operational amplifier 602 serves in FIG. 17 corresponding to the amplifier 60 from the evaluation electronics shown in FIGS.
  • a low-pass filter is shown in FIG. 17 with the reference numeral 71, which serves to band-limit the useful signal 700, which reduces the Noise component and an increase in the signal-to-noise ratio is used.
  • a filter 70 in FIG. Bandpass filter 72 are used for filtering 70, which results in the possibility of offset voltages and slow drifting of the signal, e.g. B. due to temperature changes - to el ⁇ ninieren.
  • the sensitivity of the sensor 1 can be influenced by the use as a fluid of filling gases other than air or by the use of different filling pressures of the gas surrounding the sensor. Both the density of the gas used and its heat capacity are important. The sensor can thus be set for different measuring ranges.

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  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Investigating Or Analyzing Materials Using Thermal Means (AREA)
  • Indicating Or Recording The Presence, Absence, Or Direction Of Movement (AREA)
  • Micromachines (AREA)

Abstract

L'invention concerne un capteur thermique (1) et un procédé associé. Ledit capteur servant à mesurer le déplacement d'un fluide par rapport à une unité de chauffage (30), en particulier dans le but de déterminer une accélération ou des chocs. Ledit capteur comprend des moyens de mesures de température (30, 31) qui mesurent la température du fluide en un point de mesure, en fonction du déplacement du fluide. Le point de mesure correspond à l'emplacement de l'unité de chauffage ou se trouve à proximité immédiate de cette dernière. La surveillance de la température de l'élément chauffant permet de simplifier la conception du capteur. Ce dernier permet d'effectuer des mesures multidimensionnelles. Il est possible de faire varier la puissance calorifique en fonction de la température ambiante.
EP03709632A 2002-07-05 2003-02-19 Capteur thermique pour detecter une acceleration ou un choc, comportant une unite de chauffage, et procede associe Withdrawn EP1521972A1 (fr)

Applications Claiming Priority (3)

Application Number Priority Date Filing Date Title
DE10230198A DE10230198A1 (de) 2002-07-05 2002-07-05 Sensor mit einer Heizeinrichtung und Verfahren
DE10230198 2002-07-05
PCT/DE2003/000502 WO2004005942A1 (fr) 2002-07-05 2003-02-19 Capteur thermique pour detecter une acceleration ou un choc, comportant une unite de chauffage, et procede associe

Publications (1)

Publication Number Publication Date
EP1521972A1 true EP1521972A1 (fr) 2005-04-13

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Application Number Title Priority Date Filing Date
EP03709632A Withdrawn EP1521972A1 (fr) 2002-07-05 2003-02-19 Capteur thermique pour detecter une acceleration ou un choc, comportant une unite de chauffage, et procede associe

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Country Link
US (1) US20050011260A1 (fr)
EP (1) EP1521972A1 (fr)
JP (1) JP2005532540A (fr)
DE (1) DE10230198A1 (fr)
WO (1) WO2004005942A1 (fr)

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DE102010042307B4 (de) * 2010-10-12 2018-04-12 Innovative Sensor Technology Ist Ag Strömungssensor
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US20050011260A1 (en) 2005-01-20
DE10230198A1 (de) 2004-01-22
WO2004005942A1 (fr) 2004-01-15

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