WO2021123644A1 - Electronic device comprising an inertial measurement unit - Google Patents

Electronic device comprising an inertial measurement unit Download PDF

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Publication number
WO2021123644A1
WO2021123644A1 PCT/FR2020/052506 FR2020052506W WO2021123644A1 WO 2021123644 A1 WO2021123644 A1 WO 2021123644A1 FR 2020052506 W FR2020052506 W FR 2020052506W WO 2021123644 A1 WO2021123644 A1 WO 2021123644A1
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WO
WIPO (PCT)
Prior art keywords
electronic device
inertial unit
polymer material
electronic card
electronic
Prior art date
Application number
PCT/FR2020/052506
Other languages
French (fr)
Inventor
Julien MAURAT
Original Assignee
Beyond Your Motion
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Filing date
Publication date
Application filed by Beyond Your Motion filed Critical Beyond Your Motion
Publication of WO2021123644A1 publication Critical patent/WO2021123644A1/en

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Classifications

    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01C—MEASURING DISTANCES, LEVELS OR BEARINGS; SURVEYING; NAVIGATION; GYROSCOPIC INSTRUMENTS; PHOTOGRAMMETRY OR VIDEOGRAMMETRY
    • G01C21/00—Navigation; Navigational instruments not provided for in groups G01C1/00 - G01C19/00
    • G01C21/10—Navigation; Navigational instruments not provided for in groups G01C1/00 - G01C19/00 by using measurements of speed or acceleration
    • G01C21/12—Navigation; Navigational instruments not provided for in groups G01C1/00 - G01C19/00 by using measurements of speed or acceleration executed aboard the object being navigated; Dead reckoning
    • G01C21/16—Navigation; Navigational instruments not provided for in groups G01C1/00 - G01C19/00 by using measurements of speed or acceleration executed aboard the object being navigated; Dead reckoning by integrating acceleration or speed, i.e. inertial navigation
    • G01C21/166—Mechanical, construction or arrangement details of inertial navigation systems
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01C—MEASURING DISTANCES, LEVELS OR BEARINGS; SURVEYING; NAVIGATION; GYROSCOPIC INSTRUMENTS; PHOTOGRAMMETRY OR VIDEOGRAMMETRY
    • G01C21/00—Navigation; Navigational instruments not provided for in groups G01C1/00 - G01C19/00
    • G01C21/10—Navigation; Navigational instruments not provided for in groups G01C1/00 - G01C19/00 by using measurements of speed or acceleration
    • G01C21/12—Navigation; Navigational instruments not provided for in groups G01C1/00 - G01C19/00 by using measurements of speed or acceleration executed aboard the object being navigated; Dead reckoning
    • G01C21/16—Navigation; Navigational instruments not provided for in groups G01C1/00 - G01C19/00 by using measurements of speed or acceleration executed aboard the object being navigated; Dead reckoning by integrating acceleration or speed, i.e. inertial navigation
    • G01C21/183—Compensation of inertial measurements, e.g. for temperature effects
    • H—ELECTRICITY
    • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05K—PRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS
    • H05K1/00—Printed circuits
    • H05K1/02—Details
    • H05K1/0271—Arrangements for reducing stress or warp in rigid printed circuit boards, e.g. caused by loads, vibrations or differences in thermal expansion
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01P—MEASURING LINEAR OR ANGULAR SPEED, ACCELERATION, DECELERATION, OR SHOCK; INDICATING PRESENCE, ABSENCE, OR DIRECTION, OF MOVEMENT
    • G01P21/00—Testing or calibrating of apparatus or devices covered by the preceding groups
    • H—ELECTRICITY
    • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05K—PRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS
    • H05K1/00—Printed circuits
    • H05K1/02—Details
    • H05K1/0201—Thermal arrangements, e.g. for cooling, heating or preventing overheating
    • H05K1/0203—Cooling of mounted components
    • H05K1/0204—Cooling of mounted components using means for thermal conduction connection in the thickness direction of the substrate
    • H—ELECTRICITY
    • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05K—PRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS
    • H05K1/00—Printed circuits
    • H05K1/02—Details
    • H05K1/0201—Thermal arrangements, e.g. for cooling, heating or preventing overheating
    • H05K1/0203—Cooling of mounted components
    • H05K1/0209—External configuration of printed circuit board adapted for heat dissipation, e.g. lay-out of conductors, coatings
    • H—ELECTRICITY
    • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05K—PRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS
    • H05K1/00—Printed circuits
    • H05K1/02—Details
    • H05K1/0277—Bendability or stretchability details
    • H05K1/0278—Rigid circuit boards or rigid supports of circuit boards locally made bendable, e.g. by removal or replacement of material
    • H—ELECTRICITY
    • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05K—PRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS
    • H05K2201/00—Indexing scheme relating to printed circuits covered by H05K1/00
    • H05K2201/06—Thermal details
    • H05K2201/068—Thermal details wherein the coefficient of thermal expansion is important
    • H—ELECTRICITY
    • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05K—PRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS
    • H05K2201/00—Indexing scheme relating to printed circuits covered by H05K1/00
    • H05K2201/09—Shape and layout
    • H05K2201/09009—Substrate related
    • H05K2201/09063—Holes or slots in insulating substrate not used for electrical connections
    • H—ELECTRICITY
    • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05K—PRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS
    • H05K2201/00—Indexing scheme relating to printed circuits covered by H05K1/00
    • H05K2201/10—Details of components or other objects attached to or integrated in a printed circuit board
    • H05K2201/10007—Types of components
    • H05K2201/10151—Sensor
    • H—ELECTRICITY
    • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05K—PRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS
    • H05K3/00—Apparatus or processes for manufacturing printed circuits
    • H05K3/22—Secondary treatment of printed circuits
    • H05K3/28—Applying non-metallic protective coatings
    • H05K3/284—Applying non-metallic protective coatings for encapsulating mounted components

Definitions

  • the present invention relates to an electronic device comprising an electronic card and an inertial unit mounted on the electronic card.
  • the electronic device is for example a movement sensor, without this being limiting in the context of the present invention.
  • Inertial units are electronic devices that measure forces, angular velocities and orientations by combining data from accelerometers, gyroscopes and sometimes magnetometers. These different sensors are known to drift in time, that is to say that they shift in time from their reference position and that the data that come out of them is less and less accurate over time and over time. movements.
  • inertial units consist of a microelectromechanical system, also called MEMS (standing for “MicroElectroMechanical Systems”).
  • MEMS microelectromechanical System
  • Such a MEMS microsystem comprises one or more electromechanical components.
  • the use of a magnetometer makes it possible to limit the drift of the data over time, by referring to the terrestrial magnetic field.
  • Such a magnetometer makes it possible to reliably know the orientation of the inertial unit and its measurement does not drift, unlike the gyroscope and the accelerometer.
  • this terrestrial magnetic field can be disturbed by the environment, depending on the environment where the inertial unit is used.
  • MEMS inertial units incorporating a magnetometer continue to drift as soon as the environment induces a fluctuating magnetic field, as is the case for example when the inertial unit is close to a metallic source. , or a magnet.
  • This drift makes it impossible in practice to take reliable measurements over time.
  • electronic devices are known incorporating an inertial unit in which a system for compensating the drift of the gyroscope and of the accelerometer as a function of temperature has been provided. Indeed, it has been observed that the temperature fluctuations of these sensors, even minimal, have a significant influence on the quality of the measurement.
  • Such a compensation system which makes it possible to dispense with a magnetometer (and therefore to overcome the complexity inherent in the treatment of fluctuations in the terrestrial magnetic field, which are essentially unpredictable), is for example described in patent document FR 3,037,672. B1.
  • the electronic device comprises, in addition to the inertial unit, an electronic card.
  • the compensation system comprises a thermal regulation component mounted on the electronic card near the inertial unit, and connected to the latter via a thermal guide.
  • the system also includes a temperature sensor configured to measure the temperature of the inertial unit.
  • the thermal regulation component is connected to the temperature sensor via a servo loop.
  • thermal guide generally in the form of a metal plate, increases the manufacturing costs as well as the size of the system, and makes its manufacture more complex.
  • the aim of the invention is therefore to provide an electronic device with an inertial unit overcoming the aforementioned drawbacks and making it possible in particular to standardize the temperature within and around the inertial unit, in order to improve the quality of the measurements without resorting to a magnetometer.
  • the invention relates to an electronic device comprising an electronic card and an inertial unit mounted on the electronic card, the inertial unit comprising at least one gyrometric sensor and / or at least one accelerometric sensor, the electronic device further comprising an polymeric material, said polymeric material being placed on the electronic card so as to form an envelope which covers at least the inertial unit.
  • a cutout is made in the electronic card, around the inertial unit, so as to form a support island by releasing material at the level of the electronic card, the inertial unit being mounted on the support island, the support and the rest of the electronic card being integrally connected by a bridge.
  • the polymer material which covers at least the inertial unit, the latter is isolated from external climatic conditions such as humidity and temperature. Due to its opacity, the polymer material also protects the inertial unit (and in particular the silicon chip contained in this unit) against external sources of intense light. Such intense light sources can indeed affect the quality of the measurement.
  • the polymer material also makes it possible to limit the losses by convection of the inertial unit, and thus makes it possible to obtain a standardization of the temperature within and around the latter and between the inertial unit and the electronic card. This thus makes it possible to avoid the mechanical deformations of the assembly, due to thermal expansion, thus offering an improvement in the quality of the measurements.
  • the combination between a polymer material forming an envelope which covers the inertial unit, and a support island as specified above makes it possible to limit the transmission to the inertial unit of the mechanical deformations that the electronic card undergoes.
  • the electronic card can undergo mechanical deformations which can be caused for example by its fastenings to the housing of the electronic device, by an external constraint such as the pressure by the user on the housing or by an expansion phenomenon. thermal.
  • such a configuration makes it possible to limit the heat exchanges between the inertial unit and the rest of the device (and therefore the disturbances of the inertial unit that may result therefrom), and vice versa.
  • the cutting made in the electronic card to form the support island is advantageously obtained via the same process as that used to form the card.
  • the island and the bridge can be advantageously dimensioned, and their shape calculated, so as to obtain a specific frequency response to external vibrations and to minimize heat losses by conduction in the bridge.
  • the polymer material forms a closed envelope extending on either side of the electronic card and encapsulating the inertial unit as well as the support island. This further improves the temperature uniformity within and around the inertial unit.
  • the inventors have observed that the fact of combining the protection offered by the polymer material, which encapsulates both the inertial unit and the support island, with the properties specific to this island, produces an unexpected stabilizing effect of temperature and reduction of thermomechanical deformations of the assembly. The structural homogenization of the electronic device is then greatly improved, thus producing a notable improvement in performance, in particular in measurement performance.
  • the electronic device further comprises a temperature probe configured to measure the temperature of the inertial unit, and at least one thermal regulation component mounted on the electronic card near the inertial unit, said at least one thermal regulation component. being connected to the temperature probe via a servo loop.
  • a temperature probe configured to measure the temperature of the inertial unit
  • at least one thermal regulation component mounted on the electronic card near the inertial unit, said at least one thermal regulation component. being connected to the temperature probe via a servo loop.
  • the polymer material further covers said at least one thermal regulation component.
  • the device further comprises a layer of waterproof material covering the polymer material.
  • a layer of waterproof material covering the polymer material.
  • the layer of waterproof material preferably consists of a heat-shrinkable sheath. The use of such a heat-shrinkable sheath makes it possible to facilitate adhesion with the polymer material located below the layer of waterproof material.
  • any other waterproof material or film can be used to form the waterproof material layer.
  • the polymer material is chosen from the group consisting of: an epoxy, a silicone, a polyurethane and a Bingham fluid.
  • the polymer material has a thermal conduction of between 0.2 W / m.K and 3 W / m.K.
  • a thermal conduction of between 0.2 W / m.K and 3 W / m.K.
  • the polymer material has a coefficient of thermal expansion of between 10 ppm / K and 100 ppm / K.
  • a coefficient of thermal expansion coefficient makes it possible to limit the mechanical stresses and forces with the electronic card by limiting the difference in coefficients between the electronic card and the polymer material.
  • the inertial unit consists of a MEMS microelectromechanical system comprising one or more electromechanical components.
  • the electronic device is a movement sensor.
  • FIG. 1 is a perspective view of an electronic device with an inertial unit according to one embodiment of the invention
  • FIG. 2 is a top view of the electronic device of FIG. 1;
  • FIG. 3 is a side view of the electronic device of FIG. 1; and
  • FIG. 4 is a sectional view of the electronic device of FIG. 3, taken along the section plane IV-IV.
  • FIGS. 1 to 4 represent an electronic device 1 comprising an electronic card 2, an inertial unit 4 mounted on the electronic card 2 (the latter being visible in FIG. 4), and a polymer material 6.
  • the electronic device 1 also comprises a temperature probe and at least one thermal regulation component, such elements not being shown in the figures for reasons of clarity.
  • the temperature probe is integrated within a single electromechanical MEMS component (standing for MicroElectroMechanical System).
  • the electronic device 1 also comprises a layer of waterproof material covering the polymer material 6 (such a layer of waterproof material not being shown in the figures for reasons of clarity).
  • the layer of waterproof material preferably consists of a heat-shrinkable sleeve.
  • any other waterproof material or film can be used to form the layer of waterproof material.
  • the electronic device 1 is for example a movement sensor, without this being limiting in the context of the present invention.
  • the electronic card 2 is typically a printed circuit card.
  • a cutout 8 is made in the electronic card 2, around the inertial unit 4.
  • This cutout 8 forms a support island 10 by releasing material at the level of the card. electronic 2.
  • the cutout 8 has a substantially rectangular shape. In a variant not shown, any other geometric shape can be envisaged for the cutout 8.
  • Such a cutout 8 in the electronic card 2 is advantageously obtained via the same process as that used to form the electronic card 2 itself. This makes it possible to obtain miniaturization as well as a reduction in manufacturing costs, since no additional component in addition to the card 2 itself is necessary to obtain this isolation of the inertial unit 4 from the rest. of card 2.
  • the support island 10 and the rest of the electronic card 2 are integral by being connected by a bridge 12.
  • the signals between the inertial unit 4 and the rest of the electronic card 2 pass through this bridge 12.
  • the inertial unit 4 is mounted on the support island 10, which makes it possible to limit the transmission to the inertial unit 4 of the mechanical deformations to which the electronic card 2 undergoes.
  • such a configuration makes it possible to limit the thermal exchanges between the inertial unit 4 and the rest of the device 1 (and therefore the disturbances of the inertial unit 4 that may result therefrom), and vice versa.
  • the presence of an electric power supply circuit on the electronic card 2 would be liable to disturb the inertial unit 4, which this configuration with support island 10 avoids.
  • the electronic device 1 comprises a temperature probe and at least one thermal regulation component
  • a configuration means that, in the thermal regulation of the inertial unit 4, much less energy is lost by conduction with the rest of the device 1 and that a more uniform variation of the temperature is obtained on the island 10.
  • the thermal regulation then acts much more quickly than if there were no support island 10, because it acts on a very reduced thermal mass compared to a monolithic electronic card 2.
  • the inertial unit 4 comprises at least one gyrometric sensor and / or at least one accelerometric sensor, the latter not being shown in the figures for reasons of clarity.
  • the inertial unit 4 consists of a MEMS microelectromechanical system (from the English MicroElectroMechanical System).
  • MEMS microelectromechanical system comprises one or more electromechanical components, some of which are for example gyrometric and / or accelerometric sensors in the present example.
  • the polymer material 6 is placed on the electronic card 2 so as to form an envelope which covers at least the inertial unit 4.
  • the polymer material 6 is placed on the island. of support 10 and forms an envelope which covers the inertial unit 4 as well as the thermal regulation component (not shown).
  • the presence of the polymer material 6 makes it possible to limit the losses by convection of the inertial unit 4, and thus makes it possible to obtain a standardization of the temperature within and around this last and between the inertial unit 4 and the electronic card 2.
  • the polymer material 6 also makes it possible to improve the thermal conduction between the inertial unit 4 and the part of the electronic card 2 located under the inertial unit 4, again participating in the temperature uniformity.
  • the polymer material 6 can form a closed envelope extending on either side of the electronic card 2 and encapsulating the inertial unit 4 as well as the support island 10. This makes it possible to further improve the '' standardization of the temperature within and around the inertial unit 4.
  • the polymer material 6 is for example an epoxy.
  • the polymeric material 6 can also be a silicone, or else a polyurethane, or else a Bingham fluid.
  • the polymer material 6 has a thermal conduction of between 0.2 W / m.K and 3 W / m.K. More preferably, the polymer material 6 has a coefficient of thermal expansion of between 10 ppm / K and 100 ppm / K.
  • the polymer material 6 is deposited on the inertial unit 4 after assembly of the latter on the electronic card 2.
  • the thermal regulation component is mounted on the electronic card 2, near the inertial unit 4, and is connected to the temperature sensor via a control loop.
  • the thermal regulation component is for example a heating resistor.
  • the temperature probe is configured to measure the temperature of the inertial unit 4, and to provide a measured temperature value to a temperature regulator present in the control loop.
  • the envelope formed by the polymer material 6 has a substantially hemispherical shape.
  • the invention is in no way limited to this type of particular shape for the polymer material 6, and in practice the envelope formed by this polymer material 6 can have any type of shape.

Abstract

The invention relates to an electronic device (1) comprising a circuit board (2) and an inertial measurement unit mounted on the circuit board (2), the inertial measurement unit comprising at least one gyroscopic sensor and/or at least one accelerometric sensor. According to the invention, the electronic device (1) further comprises a polymer material (6), said polymer material (6) being arranged on the circuit board (2) so as to form an envelope that covers at least the inertial measurement unit.

Description

DISPOSITIF ELECTRONIQUE COMPORTANT UNE CENTRALE INERTIELLE ELECTRONIC DEVICE INCLUDING AN INERTIAL PLANT
Domaine technique Technical area
La présente invention concerne un dispositif électronique comportant une carte électronique et une centrale inertielle montée sur la carte électronique. Le dispositif électronique est par exemple un capteur de mouvement, sans que cela ne soit limitatif dans le cadre de la présente invention. The present invention relates to an electronic device comprising an electronic card and an inertial unit mounted on the electronic card. The electronic device is for example a movement sensor, without this being limiting in the context of the present invention.
Etat de la technique State of the art
Les centrales inertielles sont des dispositifs électroniques qui permettent de mesurer des forces, des vitesses angulaires et des orientations en combinant des données issues d’accéléromètres, de gyroscopes et parfois de magnétomètres. Ces différents capteurs sont connus pour dériver dans le temps, c’est-à-dire qu’ils se décalent dans le temps de leur position de référence et que les données qui en sortent sont de moins en moins exactes au fil du temps et des mouvements. Inertial units are electronic devices that measure forces, angular velocities and orientations by combining data from accelerometers, gyroscopes and sometimes magnetometers. These different sensors are known to drift in time, that is to say that they shift in time from their reference position and that the data that come out of them is less and less accurate over time and over time. movements.
Dans le domaine des centrales inertielles, il est connu que certaines centrales inertielles soient constituées d’un microsystème électromécanique, aussi appelé MEMS (de l’anglais « MicroElectroMechanical Systems »). Un tel microsystème MEMS comprend un ou plusieurs composants électromécaniques. Dans de telles centrales inertielles sous forme de MEMS, l’usage d’un magnétomètre permet de limiter la dérive des données dans le temps, en se référant au champ magnétique terrestre. Un tel magnétomètre permet de connaître de manière fiable l’orientation de la centrale inertielle et sa mesure ne dérive pas, contrairement au gyroscope et à l’accéléromètre. Pour autant ce champ magnétique terrestre peut être perturbé par l’environnement, en fonction de l’environnement où est utilisée la centrale inertielle. Or, cette fluctuation étant très difficile à prévoir, les centrales inertielles MEMS intégrant un magnétomètre continuent de dériver dès que l’environnement induit un champ magnétique fluctuant, comme c’est le cas par exemple lorsque la centrale inertielle est proche d’une source métallique, ou encore d’un aimant. Cette dérive rend en pratique impossible la réalisation de mesures fiables dans le temps. Pour répondre à cette problématique, il est connu des dispositifs électroniques intégrant une centrale inertielle dans laquelle un système de compensation de la dérive du gyroscope et de l’accéléromètre en fonction de la température a été prévu. En effet, il a été constaté que les fluctuations de températures de ces capteurs, même minimes, ont une influence importante sur la qualité de la mesure. Un tel système de compensation, qui permet de se passer de magnétomètre (et donc de s’affranchir de la complexité inhérente au traitement des fluctuations de champ magnétique terrestre, par essence imprévisibles), est par exemple décrit dans le document brevet FR 3 037 672 B1 . In the field of inertial units, it is known that certain inertial units consist of a microelectromechanical system, also called MEMS (standing for “MicroElectroMechanical Systems”). Such a MEMS microsystem comprises one or more electromechanical components. In such inertial units in the form of MEMS, the use of a magnetometer makes it possible to limit the drift of the data over time, by referring to the terrestrial magnetic field. Such a magnetometer makes it possible to reliably know the orientation of the inertial unit and its measurement does not drift, unlike the gyroscope and the accelerometer. However, this terrestrial magnetic field can be disturbed by the environment, depending on the environment where the inertial unit is used. However, this fluctuation being very difficult to predict, MEMS inertial units incorporating a magnetometer continue to drift as soon as the environment induces a fluctuating magnetic field, as is the case for example when the inertial unit is close to a metallic source. , or a magnet. This drift makes it impossible in practice to take reliable measurements over time. To respond to this problem, electronic devices are known incorporating an inertial unit in which a system for compensating the drift of the gyroscope and of the accelerometer as a function of temperature has been provided. Indeed, it has been observed that the temperature fluctuations of these sensors, even minimal, have a significant influence on the quality of the measurement. Such a compensation system, which makes it possible to dispense with a magnetometer (and therefore to overcome the complexity inherent in the treatment of fluctuations in the terrestrial magnetic field, which are essentially unpredictable), is for example described in patent document FR 3,037,672. B1.
Dans ce document le dispositif électronique comporte, outre la centrale inertielle, une carte électronique. Le système de compensation comprend un composant de régulation thermique monté sur la carte électronique à proximité de la centrale inertielle, et relié à cette dernière via un guide thermique. Le système comprend également un capteur de température configuré pour mesurer la température de la centrale inertielle. Le composant de régulation thermique est relié au capteur de température via une boucle d’asservissement. Un tel système de compensation permet de stabiliser la température de la centrale inertielle par réchauffement de cette dernière via l’utilisation du composant de régulation thermique, ceci afin de garantir une température souhaitée pour la centrale. Toutefois, un inconvénient d’un tel système est que la centrale inertielle n’est pas isolée de l’influence de certaines conditions climatiques, dont l’humidité. Ceci peut créer des pertes par convexion, de telles pertes étant préjudiciables à l’uniformité de la température au sein et autour de la centrale inertielle. En outre la présence d’un guide thermique, sous forme généralement d’une plaque métallique, augmente les coûts de fabrication ainsi que l’encombrement du système, et complexifie sa fabrication. In this document, the electronic device comprises, in addition to the inertial unit, an electronic card. The compensation system comprises a thermal regulation component mounted on the electronic card near the inertial unit, and connected to the latter via a thermal guide. The system also includes a temperature sensor configured to measure the temperature of the inertial unit. The thermal regulation component is connected to the temperature sensor via a servo loop. Such a compensation system makes it possible to stabilize the temperature of the inertial unit by heating the latter through the use of the thermal regulation component, in order to guarantee a desired temperature for the unit. However, a drawback of such a system is that the inertial unit is not isolated from the influence of certain climatic conditions, including humidity. This can create convection losses, such losses being detrimental to temperature uniformity within and around the inertial unit. In addition, the presence of a thermal guide, generally in the form of a metal plate, increases the manufacturing costs as well as the size of the system, and makes its manufacture more complex.
Résumé de l’invention Summary of the invention
L’invention a donc pour but de fournir un dispositif électronique à centrale inertielle palliant les inconvénients susmentionnés et permettant notamment d’uniformiser la température au sein et autour de la centrale inertielle, afin d’améliorer la qualité des mesures et ce sans recourir à un magnétomètre. A cet effet, l’invention concerne un dispositif électronique comportant une carte électronique et une centrale inertielle montée sur la carte électronique, la centrale inertielle comprenant au moins un capteur gyrométrique et/ou au moins un capteur accélérométrique, le dispositif électronique comportant en outre un matériau polymère, ledit matériau polymère étant disposé sur la carte électronique de sorte à former une enveloppe qui recouvre au moins la centrale inertielle. Un découpage est pratiqué dans la carte électronique, autour de la centrale inertielle, de sorte à former un îlot de support par dégagement de matière au niveau de la carte électronique, la centrale inertielle étant montée sur l’îlot de support, l’îlot de support et le reste de la carte électronique étant venus de matière en étant reliés par un pont. The aim of the invention is therefore to provide an electronic device with an inertial unit overcoming the aforementioned drawbacks and making it possible in particular to standardize the temperature within and around the inertial unit, in order to improve the quality of the measurements without resorting to a magnetometer. To this end, the invention relates to an electronic device comprising an electronic card and an inertial unit mounted on the electronic card, the inertial unit comprising at least one gyrometric sensor and / or at least one accelerometric sensor, the electronic device further comprising an polymeric material, said polymeric material being placed on the electronic card so as to form an envelope which covers at least the inertial unit. A cutout is made in the electronic card, around the inertial unit, so as to form a support island by releasing material at the level of the electronic card, the inertial unit being mounted on the support island, the support and the rest of the electronic card being integrally connected by a bridge.
Grâce à la présence du matériau polymère, qui recouvre au moins la centrale inertielle, cette dernière est isolée des conditions climatiques extérieures telles que l’humidité et la température. Du fait de son opacité, le matériau polymère protège également la centrale inertielle (et notamment la puce silicium contenue dans cette centrale) contre des sources externes de lumière intense. De telles sources de lumière intense peuvent en effet affecter la qualité de la mesure. Le matériau polymère permet également de limiter les pertes par convexion de la centrale inertielle, et permet ainsi d’obtenir une uniformisation de la température au sein et autour de cette dernière et entre la centrale inertielle et la carte électronique. Ceci permet ainsi d’éviter les déformations mécaniques de l’ensemble, dues à la dilatation thermique, offrant ainsi une amélioration dans la qualité des mesures. En outre, la combinaison entre un matériau polymère formant une enveloppe qui recouvre la centrale inertielle, et un îlot de support tel que spécifié ci-dessus, permet de limiter la transmission à la centrale inertielle des déformations mécaniques que subit la carte électronique. En effet, la carte électronique peut subir des déformations mécaniques qui peuvent être causées par exemple par ses fixations au boîtier du dispositif électronique, par une contrainte externe telle que l’appui par l’utilisateur sur le boîtier ou encore par un phénomène d’expansion thermique. En outre, une telle configuration permet de limiter les échanges thermiques entre la centrale inertielle et le reste du dispositif (et donc les perturbations de la centrale inertielle pouvant en résulter), et inversement. Le découpage pratiqué dans la carte électronique pour former l’îlot de support est avantageusement obtenu via le même procédé que celui utilisé pour former la carte électronique. Ceci permet d’obtenir une miniaturisation ainsi qu’une réduction des coûts de fabrication. L’îlot et le pont peuvent être avantageusement dimensionnés, et leur forme calculée, de sorte à obtenir une réponse fréquentielle spécifique aux vibrations externes et à minimiser les pertes thermiques par conduction dans le pont. Thanks to the presence of the polymer material, which covers at least the inertial unit, the latter is isolated from external climatic conditions such as humidity and temperature. Due to its opacity, the polymer material also protects the inertial unit (and in particular the silicon chip contained in this unit) against external sources of intense light. Such intense light sources can indeed affect the quality of the measurement. The polymer material also makes it possible to limit the losses by convection of the inertial unit, and thus makes it possible to obtain a standardization of the temperature within and around the latter and between the inertial unit and the electronic card. This thus makes it possible to avoid the mechanical deformations of the assembly, due to thermal expansion, thus offering an improvement in the quality of the measurements. In addition, the combination between a polymer material forming an envelope which covers the inertial unit, and a support island as specified above, makes it possible to limit the transmission to the inertial unit of the mechanical deformations that the electronic card undergoes. Indeed, the electronic card can undergo mechanical deformations which can be caused for example by its fastenings to the housing of the electronic device, by an external constraint such as the pressure by the user on the housing or by an expansion phenomenon. thermal. In addition, such a configuration makes it possible to limit the heat exchanges between the inertial unit and the rest of the device (and therefore the disturbances of the inertial unit that may result therefrom), and vice versa. The cutting made in the electronic card to form the support island is advantageously obtained via the same process as that used to form the card. electronic. This makes it possible to obtain miniaturization as well as a reduction in manufacturing costs. The island and the bridge can be advantageously dimensioned, and their shape calculated, so as to obtain a specific frequency response to external vibrations and to minimize heat losses by conduction in the bridge.
Avantageusement, le matériau polymère forme une enveloppe fermée s’étendant de part et d’autre de la carte électronique et encapsulant la centrale inertielle ainsi que l’îlot de support. Ceci permet d’améliorer encore l’uniformisation de la température au sein et autour de la centrale inertielle. De plus, les inventeurs ont constaté que le fait de combiner la protection offerte par le matériau polymère, qui encapsule à la fois la centrale inertielle et l’îlot de support, avec les propriétés propres à cet îlot, produit un effet inattendu de stabilisation de la température et de réduction des déformations thermomécaniques de l’ensemble. L’homogénéisation structurelle du dispositif électronique est alors grandement améliorée, produisant ainsi une amélioration notable des performances, notamment des performances de mesure. Advantageously, the polymer material forms a closed envelope extending on either side of the electronic card and encapsulating the inertial unit as well as the support island. This further improves the temperature uniformity within and around the inertial unit. In addition, the inventors have observed that the fact of combining the protection offered by the polymer material, which encapsulates both the inertial unit and the support island, with the properties specific to this island, produces an unexpected stabilizing effect of temperature and reduction of thermomechanical deformations of the assembly. The structural homogenization of the electronic device is then greatly improved, thus producing a notable improvement in performance, in particular in measurement performance.
Avantageusement, le dispositif électronique comporte en outre une sonde de température configurée pour mesurer la température de la centrale inertielle, et au moins un composant de régulation thermique monté sur la carte électronique à proximité de la centrale inertielle, ledit au moins un composant de régulation thermique étant relié à la sonde de température via une boucle d’asservissement. Ceci permet de stabiliser la température au sein de la centrale inertielle en compensant les variations de température. En outre, la combinaison entre ces caractéristiques et la présence du matériau polymère permet avantageusement de se passer de guide thermique sous forme de plaque métallique. Enfin, la présence du matériau polymère crée un couplage thermique ce qui permet d’uniformiser le gradient en température et d’améliorer ainsi la conduction thermique entre la centrale inertielle et le composant de régulation thermique. Advantageously, the electronic device further comprises a temperature probe configured to measure the temperature of the inertial unit, and at least one thermal regulation component mounted on the electronic card near the inertial unit, said at least one thermal regulation component. being connected to the temperature probe via a servo loop. This makes it possible to stabilize the temperature within the inertial unit by compensating for temperature variations. In addition, the combination between these characteristics and the presence of the polymer material advantageously makes it possible to dispense with a thermal guide in the form of a metal plate. Finally, the presence of the polymer material creates a thermal coupling which makes it possible to standardize the temperature gradient and thus improve the thermal conduction between the inertial unit and the thermal regulation component.
Selon une caractéristique technique particulière de l’invention, le matériau polymère recouvre en outre ledit au moins un composant de régulation thermique. According to a particular technical characteristic of the invention, the polymer material further covers said at least one thermal regulation component.
Avantageusement, le dispositif comporte en outre une couche de matériau étanche recouvrant le matériau polymère. Ceci permet d’étanchéifier l'îlot de support afin de limiter l'intrusion d'humidité dans le matériau polymère ainsi que dans le reste de l'îlot. Le taux d'humidité affecte en effet la mesure et cela permet donc d'avoir une mesure stable dans le temps sur le long terme. La couche de matériau étanche est de préférence constituée d’une gaine thermorétractable. L’utilisation d’une telle gaine thermorétractable permet en effet de faciliter l’adhérence avec le matériau polymère situé en-dessous de la couche de matériau étanche. En variante, tout autre matériau ou film étanche peut être utilisé pour former la couche de matériau étanche. Advantageously, the device further comprises a layer of waterproof material covering the polymer material. This makes it possible to seal the support island in order to limit the intrusion of moisture into the polymer material as well as into the rest of the island. The humidity level indeed affects the measurement and this therefore allows to have a long-term stable measurement. The layer of waterproof material preferably consists of a heat-shrinkable sheath. The use of such a heat-shrinkable sheath makes it possible to facilitate adhesion with the polymer material located below the layer of waterproof material. Alternatively, any other waterproof material or film can be used to form the waterproof material layer.
Selon une autre caractéristique technique particulière de l’invention, le matériau polymère est choisi parmi le groupe consistant en : un époxy, un silicone, un polyuréthane et un fluide de Bingham. According to another particular technical characteristic of the invention, the polymer material is chosen from the group consisting of: an epoxy, a silicone, a polyurethane and a Bingham fluid.
Avantageusement, le matériau polymère présente une conduction thermique comprise entre 0,2 W/m.K et 3 W/m.K. Une telle plage de valeurs pour la conduction thermique permet d’optimiser la relation entre l’isolement assuré par le matériau polymère vis-à-vis de la convexion extérieure, et le couplage thermique par conduction. Advantageously, the polymer material has a thermal conduction of between 0.2 W / m.K and 3 W / m.K. Such a range of values for thermal conduction makes it possible to optimize the relationship between the insulation provided by the polymer material against external convection, and thermal coupling by conduction.
Avantageusement, le matériau polymère présente un coefficient de dilatation thermique compris entre 10 ppm/K et 100 ppm/K. Une telle plage de valeurs pour le coefficient de dilatation thermique permet de limiter les contraintes et efforts mécaniques avec la carte électronique en limitant la différence de coefficients entre la carte électronique et le matériau polymère. Advantageously, the polymer material has a coefficient of thermal expansion of between 10 ppm / K and 100 ppm / K. Such a range of values for the thermal expansion coefficient makes it possible to limit the mechanical stresses and forces with the electronic card by limiting the difference in coefficients between the electronic card and the polymer material.
Selon une caractéristique technique particulière de l’invention, la centrale inertielle est constituée d’un microsystème électromécanique MEMS comprenant un ou plusieurs composants électromécaniques. According to a particular technical characteristic of the invention, the inertial unit consists of a MEMS microelectromechanical system comprising one or more electromechanical components.
Selon une autre caractéristique technique particulière de l’invention, le dispositif électronique est un capteur de mouvement. According to another particular technical characteristic of the invention, the electronic device is a movement sensor.
Brève description des figures Brief description of the figures
Les buts, avantages et caractéristiques du dispositif électronique à centrale inertielle selon l’invention, apparaîtront mieux dans la description suivante sur la base d’au moins une forme d’exécution non limitative illustrée par les dessins sur lesquels : The aims, advantages and characteristics of the electronic device with an inertial unit according to the invention will appear better in the following description on the basis of at least one non-limiting embodiment illustrated by the drawings in which:
-La figure 1 est une vue en perspective d’un dispositif électronique à centrale inertielle selon un mode de réalisation de l’invention ; FIG. 1 is a perspective view of an electronic device with an inertial unit according to one embodiment of the invention;
-La figure 2 est une vue de dessus du dispositif électronique de la figure 1 ; -La figure 3 est une vue de côté du dispositif électronique de la figure 1 ; etFIG. 2 is a top view of the electronic device of FIG. 1; FIG. 3 is a side view of the electronic device of FIG. 1; and
-La figure 4 est une vue en coupe du dispositif électronique de la figure 3, prise selon le plan de coupe IV-IV. FIG. 4 is a sectional view of the electronic device of FIG. 3, taken along the section plane IV-IV.
Description détaillée de l’invention Detailed description of the invention
Les figures 1 à 4 représentent un dispositif électronique 1 comprenant une carte électronique 2, une centrale inertielle 4 montée sur la carte électronique 2 (cette dernière étant visible sur la figure 4), et un matériau polymère 6. De préférence, le dispositif électronique 1 comprend également une sonde de température et au moins un composant de régulation thermique, de tels éléments n’étant pas représentés sur les figures pour des raisons de clarté. Dans un exemple de réalisation particulier, la sonde de température est intégrée au sein d’un seul et même composant électromécanique MEMS (de l’anglais MicroElectroMechanical System). De préférence, le dispositif électronique 1 comprend également une couche de matériau étanche recouvrant le matériau polymère 6 (une telle couche de matériau étanche n’étant pas représentée sur les figures pour des raisons de clarté). La couche de matériau étanche est de préférence constituée d’une gaine thermorétractable. En variante, tout autre matériau ou film étanche peut être utilisé pour former la couche de matériau étanche. Le dispositif électronique 1 est par exemple un capteur de mouvement, sans que cela ne soit limitatif dans le cadre de la présente invention. FIGS. 1 to 4 represent an electronic device 1 comprising an electronic card 2, an inertial unit 4 mounted on the electronic card 2 (the latter being visible in FIG. 4), and a polymer material 6. Preferably, the electronic device 1 also comprises a temperature probe and at least one thermal regulation component, such elements not being shown in the figures for reasons of clarity. In a particular exemplary embodiment, the temperature probe is integrated within a single electromechanical MEMS component (standing for MicroElectroMechanical System). Preferably, the electronic device 1 also comprises a layer of waterproof material covering the polymer material 6 (such a layer of waterproof material not being shown in the figures for reasons of clarity). The layer of waterproof material preferably consists of a heat-shrinkable sleeve. As a variant, any other waterproof material or film can be used to form the layer of waterproof material. The electronic device 1 is for example a movement sensor, without this being limiting in the context of the present invention.
La carte électronique 2 est typiquement une carte à circuit imprimé. Dans le mode de réalisation préférentiel illustré sur les figures 1 à 4, un découpage 8 est pratiqué dans la carte électronique 2, autour de la centrale inertielle 4. Ce découpage 8 forme un îlot de support 10 par dégagement de matière au niveau de la carte électronique 2. Dans l’exemple illustratif des figures 1 et 2, le découpage 8 présente une forme sensiblement rectangulaire. En variante non représentée, toute autre forme géométrique peut être envisagée pour le découpage 8. Un tel découpage 8 dans la carte électronique 2 est avantageusement obtenu via le même procédé que celui utilisé pour former la carte électronique 2 elle-même. Ceci permet d’obtenir une miniaturisation ainsi qu’une réduction des coûts de fabrication, car aucun composant additionnel en plus de la carte 2 elle-même n’est nécessaire pour obtenir cette isolation de la centrale inertielle 4 vis-à-vis du reste de la carte 2. L’îlot de support 10 et le reste de la carte électronique 2 sont venus de matière en étant reliés par un pont 12. Les signaux entre la centrale inertielle 4 et le reste de la carte électronique 2 transitent via ce pont 12. La centrale inertielle 4 est montée sur l’îlot de support 10, ce qui permet de limiter la transmission à la centrale inertielle 4 des déformations mécaniques que subit la carte électronique 2. En outre, une telle configuration permet de limiter les échanges thermiques entre la centrale inertielle 4 et le reste du dispositif 1 (et donc les perturbations de la centrale inertielle 4 pouvant en résulter), et inversement. Par exemple, la présence d’un circuit d’alimentation électrique sur la carte électronique 2 serait susceptible de venir perturber la centrale inertielle 4, ce qu’évite cette configuration avec îlot de support 10. Par ailleurs, dans l’exemple de réalisation préférentiel selon lequel le dispositif électronique 1 comprend une sonde de température et au moins un composant de régulation thermique, une telle configuration fait que, dans la régulation thermique de la centrale inertielle 4, beaucoup moins d’énergie est perdue par conduction avec le reste du dispositif 1 et qu’on obtient une variation plus uniforme de la température sur l’îlot 10. De plus, la régulation thermique agit alors beaucoup plus rapidement que s’il n’y avait pas d’îlot de support 10, car elle agit sur une masse thermique très réduite par rapport à une carte électronique 2 monolithique. The electronic card 2 is typically a printed circuit card. In the preferred embodiment illustrated in Figures 1 to 4, a cutout 8 is made in the electronic card 2, around the inertial unit 4. This cutout 8 forms a support island 10 by releasing material at the level of the card. electronic 2. In the illustrative example of Figures 1 and 2, the cutout 8 has a substantially rectangular shape. In a variant not shown, any other geometric shape can be envisaged for the cutout 8. Such a cutout 8 in the electronic card 2 is advantageously obtained via the same process as that used to form the electronic card 2 itself. This makes it possible to obtain miniaturization as well as a reduction in manufacturing costs, since no additional component in addition to the card 2 itself is necessary to obtain this isolation of the inertial unit 4 from the rest. of card 2. The support island 10 and the rest of the electronic card 2 are integral by being connected by a bridge 12. The signals between the inertial unit 4 and the rest of the electronic card 2 pass through this bridge 12. The inertial unit 4 is mounted on the support island 10, which makes it possible to limit the transmission to the inertial unit 4 of the mechanical deformations to which the electronic card 2 undergoes. In addition, such a configuration makes it possible to limit the thermal exchanges between the inertial unit 4 and the rest of the device 1 (and therefore the disturbances of the inertial unit 4 that may result therefrom), and vice versa. For example, the presence of an electric power supply circuit on the electronic card 2 would be liable to disturb the inertial unit 4, which this configuration with support island 10 avoids. Furthermore, in the preferred embodiment example according to which the electronic device 1 comprises a temperature probe and at least one thermal regulation component, such a configuration means that, in the thermal regulation of the inertial unit 4, much less energy is lost by conduction with the rest of the device 1 and that a more uniform variation of the temperature is obtained on the island 10. In addition, the thermal regulation then acts much more quickly than if there were no support island 10, because it acts on a very reduced thermal mass compared to a monolithic electronic card 2.
La centrale inertielle 4 comprend au moins un capteur gyrométrique et/ou au moins un capteur accélérométrique, ces derniers n’étant pas représentés sur les figures pour des raisons de clarté. De préférence, la centrale inertielle 4 est constituée d’un microsystème électromécanique MEMS (de l’anglais MicroElectroMechanical System). Un tel microsystème électromécanique MEMS comprend un ou plusieurs composants électromécaniques, dont certains sont par exemple les capteurs gyrométrique et/ou accélérométrique dans le présent exemple. The inertial unit 4 comprises at least one gyrometric sensor and / or at least one accelerometric sensor, the latter not being shown in the figures for reasons of clarity. Preferably, the inertial unit 4 consists of a MEMS microelectromechanical system (from the English MicroElectroMechanical System). Such a MEMS microelectromechanical system comprises one or more electromechanical components, some of which are for example gyrometric and / or accelerometric sensors in the present example.
Le matériau polymère 6 est disposé sur la carte électronique 2 de sorte à former une enveloppe qui recouvre au moins la centrale inertielle 4. Dans le mode de réalisation préférentiel illustré sur les figures 1 à 4, le matériau polymère 6 est disposé sur l’îlot de support 10 et forme une enveloppe qui recouvre la centrale inertielle 4 ainsi que le composant de régulation thermique (non représenté). La présence du matériau polymère 6 permet de limiter les pertes par convexion de la centrale inertielle 4, et permet ainsi d’obtenir une uniformisation de la température au sein et autour de cette dernière et entre la centrale inertielle 4 et la carte électronique 2. Le matériau polymère 6 permet également d’améliorer la conduction thermique entre la centrale inertielle 4 et la partie de la carte électronique 2 située sous la centrale inertielle 4, participant là encore à l’uniformisation de la température. The polymer material 6 is placed on the electronic card 2 so as to form an envelope which covers at least the inertial unit 4. In the preferred embodiment illustrated in FIGS. 1 to 4, the polymer material 6 is placed on the island. of support 10 and forms an envelope which covers the inertial unit 4 as well as the thermal regulation component (not shown). The presence of the polymer material 6 makes it possible to limit the losses by convection of the inertial unit 4, and thus makes it possible to obtain a standardization of the temperature within and around this last and between the inertial unit 4 and the electronic card 2. The polymer material 6 also makes it possible to improve the thermal conduction between the inertial unit 4 and the part of the electronic card 2 located under the inertial unit 4, again participating in the temperature uniformity.
En variante non représentée, le matériau polymère 6 peut former une enveloppe fermée s’étendant de part et d’autre de la carte électronique 2 et encapsulant la centrale inertielle 4 ainsi que l’îlot de support 10. Ceci permet d’améliorer encore l’uniformisation de la température au sein et autour de la centrale inertielle 4. In a variant not shown, the polymer material 6 can form a closed envelope extending on either side of the electronic card 2 and encapsulating the inertial unit 4 as well as the support island 10. This makes it possible to further improve the '' standardization of the temperature within and around the inertial unit 4.
Le matériau polymère 6 est par exemple un époxy. En variante, le matériau polymère 6 peut aussi être un silicone, ou bien un polyuréthane, ou encore un fluide de Bingham. De préférence, le matériau polymère 6 présente une conduction thermique comprise entre 0,2 W/m.K et 3 W/m.K. De préférence encore, le matériau polymère 6 présente un coefficient de dilatation thermique compris entre 10 ppm/K et 100 ppm/K. En ce qui concerne le procédé de fabrication du dispositif électronique 1 , le matériau polymère 6 est déposé sur la centrale inertielle 4 après assemblage de cette dernière sur la carte électronique 2. The polymer material 6 is for example an epoxy. As a variant, the polymeric material 6 can also be a silicone, or else a polyurethane, or else a Bingham fluid. Preferably, the polymer material 6 has a thermal conduction of between 0.2 W / m.K and 3 W / m.K. More preferably, the polymer material 6 has a coefficient of thermal expansion of between 10 ppm / K and 100 ppm / K. As regards the method of manufacturing the electronic device 1, the polymer material 6 is deposited on the inertial unit 4 after assembly of the latter on the electronic card 2.
Le composant de régulation thermique est monté sur la carte électronique 2, à proximité de la centrale inertielle 4, et est relié à la sonde de température via une boucle d’asservissement. Le composant de régulation thermique est par exemple une résistance chauffante. La sonde de température est configurée pour mesurer la température de la centrale inertielle 4, et pour fournir une valeur de température mesurée à un organe de régulation de température présent dans la boucle d’asservissement. The thermal regulation component is mounted on the electronic card 2, near the inertial unit 4, and is connected to the temperature sensor via a control loop. The thermal regulation component is for example a heating resistor. The temperature probe is configured to measure the temperature of the inertial unit 4, and to provide a measured temperature value to a temperature regulator present in the control loop.
Dans l’exemple de réalisation illustratif représenté sur les figures 1 à 4, l’enveloppe formée par le matériau polymère 6 présente une forme sensiblement hémisphérique. L’invention n’est toutefois nullement limitée à ce type de forme particulière pour le matériau polymère 6, et en pratique l’enveloppe formée par ce matériau polymère 6 peut présenter tout type de forme. In the illustrative embodiment shown in Figures 1 to 4, the envelope formed by the polymer material 6 has a substantially hemispherical shape. However, the invention is in no way limited to this type of particular shape for the polymer material 6, and in practice the envelope formed by this polymer material 6 can have any type of shape.

Claims

REVENDICATIONS
1 . Dispositif électronique (1 ) comportant une carte électronique (2) et une centrale inertielle (4) montée sur la carte électronique (2), la centrale inertielle (4) comprenant au moins un capteur gyrométrique et/ou au moins un capteur accélérométrique, le dispositif électronique (1 ) comportant en outre un matériau polymère (6), ledit matériau polymère (6) étant disposé sur la carte électronique (2) de sorte à former une enveloppe qui recouvre au moins la centrale inertielle (4), caractérisé en ce qu’un découpage (8) est pratiqué dans la carte électronique (2), autour de la centrale inertielle (4), de sorte à former un îlot de support (10) par dégagement de matière au niveau de la carte électronique (2), la centrale inertielle (4) étant montée sur l’îlot de support (10), l’îlot de support (10) et le reste de la carte électronique (2) étant venus de matière en étant reliés par un pont (12). 1. Electronic device (1) comprising an electronic card (2) and an inertial unit (4) mounted on the electronic card (2), the inertial unit (4) comprising at least one gyrometric sensor and / or at least one accelerometric sensor, the electronic device (1) further comprising a polymer material (6), said polymer material (6) being arranged on the electronic card (2) so as to form an envelope which covers at least the inertial unit (4), characterized in that that a cutout (8) is made in the electronic card (2), around the inertial unit (4), so as to form a support island (10) by releasing material at the level of the electronic card (2) , the inertial unit (4) being mounted on the support island (10), the support island (10) and the rest of the electronic card (2) being integrally connected by a bridge (12) .
2. Dispositif électronique (1 ) selon la revendication 1 , caractérisé en ce que le matériau polymère (6) forme une enveloppe fermée s’étendant de part et d’autre de la carte électronique (2) et encapsulant la centrale inertielle (4) ainsi que l’îlot de support (10). 2. Electronic device (1) according to claim 1, characterized in that the polymer material (6) forms a closed envelope extending on either side of the electronic card (2) and encapsulating the inertial unit (4) as well as the support island (10).
3. Dispositif électronique (1 ) selon l’une quelconque des revendications précédentes, caractérisé en ce qu’il comporte en outre une sonde de température configurée pour mesurer la température de la centrale inertielle (4), et au moins un composant de régulation thermique monté sur la carte électronique (2) à proximité de la centrale inertielle (4), ledit au moins un composant de régulation thermique étant relié à la sonde de température via une boucle d’asservissement. 3. Electronic device (1) according to any one of the preceding claims, characterized in that it further comprises a temperature probe configured to measure the temperature of the inertial unit (4), and at least one thermal regulation component. mounted on the electronic card (2) close to the inertial unit (4), said at least one thermal regulation component being connected to the temperature probe via a servo loop.
4. Dispositif électronique (1 ) selon la revendication 3, caractérisé en ce que le matériau polymère (6) recouvre en outre ledit au moins un composant de régulation thermique. 4. Electronic device (1) according to claim 3, characterized in that the polymer material (6) further covers said at least one thermal regulation component.
5. Dispositif électronique (1) selon l’une quelconque des revendications précédentes, caractérisé en ce qu’il comporte en outre une couche de matériau étanche recouvrant le matériau polymère (6), la couche de matériau étanche étant de préférence constituée d’une gaine thermorétractable. 5. Electronic device (1) according to any one of the preceding claims, characterized in that it further comprises a layer of waterproof material covering the polymer material (6), the layer of waterproof material preferably consisting of a heat-shrinkable sleeve.
6. Dispositif électronique (1) selon l’une quelconque des revendications précédentes, caractérisé en ce que le matériau polymère (6) est choisi parmi le groupe consistant en : un époxy, un silicone, un polyuréthane et un fluide de Bingham. 6. Electronic device (1) according to any one of the preceding claims, characterized in that the polymeric material (6) is selected from the group consisting of: an epoxy, a silicone, a polyurethane and a Bingham fluid.
7. Dispositif électronique (1) selon l’une quelconque des revendications précédentes, caractérisé en ce que le matériau polymère (6) présente une conduction thermique comprise entre 0,2 W/m.K et 3 W/m.K. 7. Electronic device (1) according to any one of the preceding claims, characterized in that the polymer material (6) has a thermal conduction of between 0.2 W / m.K and 3 W / m.K.
8. Dispositif électronique (1) selon l’une quelconque des revendications précédentes, caractérisé en ce que le matériau polymère (6) présente un coefficient de dilatation thermique compris entre 10 ppm/K et 100 ppm/K. 8. Electronic device (1) according to any one of the preceding claims, characterized in that the polymer material (6) has a thermal expansion coefficient of between 10 ppm / K and 100 ppm / K.
9. Dispositif électronique (1) selon l’une quelconque des revendications précédentes, caractérisé en ce que la centrale inertielle (4) est constituée d’un microsystème électromécanique MEMS comprenant un ou plusieurs composants électromécaniques. 9. Electronic device (1) according to any one of the preceding claims, characterized in that the inertial unit (4) consists of a MEMS microelectromechanical system comprising one or more electromechanical components.
10. Dispositif électronique (1) selon l’une quelconque des revendications précédentes, caractérisé en ce que le dispositif électronique (1) est un capteur de mouvement. 10. Electronic device (1) according to any one of the preceding claims, characterized in that the electronic device (1) is a motion sensor.
PCT/FR2020/052506 2019-12-18 2020-12-17 Electronic device comprising an inertial measurement unit WO2021123644A1 (en)

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FRFR1914749 2019-12-18
FR1914749A FR3105399B1 (en) 2019-12-18 2019-12-18 ELECTRONIC DEVICE COMPRISING AN INERTIAL UNIT

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Citations (6)

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WO2016005201A1 (en) * 2014-07-08 2016-01-14 Continental Teves Ag & Co. Ohg Sensor comprising a sacrificial anode
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FR3037672B1 (en) 2015-06-16 2017-06-16 Parrot DRONE COMPRISING IMPROVED COMPENSATION MEANS THROUGH THE INERTIAL CENTER BASED ON TEMPERATURE
US20170234706A1 (en) * 2010-08-26 2017-08-17 Blast Motion Inc. Method of coupling a motion sensor to a piece of equipment
WO2019033753A1 (en) * 2017-08-17 2019-02-21 深圳市道通智能航空技术有限公司 Inertial measuring device and mechanical equipment

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US7938004B1 (en) * 2008-03-21 2011-05-10 Brunsch Jr James P Systems and methods for angular rate and position measurement
US20170234706A1 (en) * 2010-08-26 2017-08-17 Blast Motion Inc. Method of coupling a motion sensor to a piece of equipment
WO2016005201A1 (en) * 2014-07-08 2016-01-14 Continental Teves Ag & Co. Ohg Sensor comprising a sacrificial anode
FR3037672B1 (en) 2015-06-16 2017-06-16 Parrot DRONE COMPRISING IMPROVED COMPENSATION MEANS THROUGH THE INERTIAL CENTER BASED ON TEMPERATURE
US20170082648A1 (en) * 2015-09-22 2017-03-23 Invensense, Inc. Systems and methods for thermally controlling sensors
WO2019033753A1 (en) * 2017-08-17 2019-02-21 深圳市道通智能航空技术有限公司 Inertial measuring device and mechanical equipment
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FR3105399B1 (en) 2022-02-04

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