JP2009223620A - Structure of assembling dynamic quantity sensor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an assembling structure of a dynamic quantity sensor capable of making vibration-proof properties of a sensor chip 7 higher and the life of the connection part of the dynamic quantity sensor 50 and an assembly member 20 longer than a conventional structure of assembling a dynamic quantity sensor, when connecting the dynamic quantity sensor 50 with the sensor chip 7 mounted on a package 1 to the assembly member 20. <P>SOLUTION: The dynamic quantity sensor 50 is constituted with the sensor chip 7, a circuit board 3 and the package 1 for mounting them, and the dynamic quantity sensor 50 is provided with a power supply means 12 for supplying the sensor chip 7 and the circuit board 3 with electric power. In addition, such the dynamic quantity sensor 50 is mechanically connected to the assembly member 20 through an adhesive 15. Moreover, the circuit board 3 is provided with a wireless part 6 that receives electric power from the power supply means 12 to operate, and a detected physical quantity is transmitted from the wireless part 6 to the outside of the dynamic quantity sensor 50. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a mechanical quantity sensor assembly structure in which a mechanical quantity sensor having a sensor chip mounted on a package is assembled to an assembly member via an adhesive.

  Conventionally, as a mechanical quantity sensor, for example, a sensor chip having a base, a vibrator provided in the base, and a detection electrode provided to face the vibrator are electrically connected to the sensor chip. An angular velocity sensor configured by including a circuit board and a package on which the sensor chip and the circuit board are mounted is known. Specifically, at such an angular velocity, a recess is formed on the surface of the package, and wiring is provided inside. A circuit board is disposed on the bottom surface of the recess, and a sensor chip is mounted on one surface of the circuit board opposite to the one surface disposed on the bottom surface of the recess, and the bottom surface of the recess, the circuit board, the circuit board, and the sensor are mounted. Each chip is connected via an adhesive. The circuit board and the sensor chip, and the circuit board and the wiring provided in the package are electrically connected via wire bonding.

  Such an angular velocity sensor is provided with an electrode electrically connected to a wiring provided in the package on one surface of the package opposite to the surface on which the recess is formed. For example, an assembly of a printed circuit board or the like Used by being mechanically and electrically connected to the member via solder bumps.

  In such an angular velocity sensor, the vibrator is driven and oscillated in one direction at a predetermined frequency. When an angular velocity is applied to the vibrating vibrator, a Coriolis force is generated, and the vibrator is driven and vibrated by the Coriolis force. It is displaced in a direction perpendicular to the direction of the movement. In this case, the angular velocity is detected by detecting a change in capacitance between the vibrator and the detection electrode.

  However, in such an angular velocity sensor, there is a problem that the detection accuracy of the angular velocity is reduced when vibration is applied to the sensor chip from the outside via the assembly member. For example, a normal vibrator is driven and vibrated at a driving vibration frequency of 5 kHz to 20 kHz. When the vibrator is driven and vibrated, vibration having an odd multiple of the driving vibration frequency is generated in the surroundings. Further, when the angular velocity sensor and the assembly member are connected via the solder bump, the structural resonance frequency between the angular velocity sensor and the assembly member is about 50 to 60 kHz.

  Then, when the vibrator is driven to vibrate, the vibration frequency generated by the vibrator is close to the structural resonance frequency between the angular velocity sensor and the assembly member, and the angular velocity sensor vibrates. For this reason, vibration is applied to the sensor chip, and there is a problem that the detection accuracy of the angular velocity is deteriorated.

Therefore, in an angular velocity sensor in which a sensor chip is mounted on a circuit board, the sensor chip and the circuit board are bonded to each other through an adhesive having vibration absorption, and external vibration applied to the sensor chip is absorbed by the adhesive film. An angular velocity sensor is disclosed (see, for example, Patent Document 1). Specifically, the vibration-proof property of the sensor chip is enhanced by adjusting the material and shape of the adhesive film to enhance the vibration absorption.
JP 2005-331258 A

  However, in the angular velocity sensor of the above-mentioned Patent Document 1, although vibration isolation between the sensor chip and the circuit board can be improved, nothing is mentioned regarding the connection between the angular velocity sensor and the assembly member, and the angular velocity sensor and the assembly member are not mentioned. It is also necessary to improve the vibration absorption of the sensor chip to improve the vibration absorption of the sensor chip.

  Further, when the angular velocity sensor as described above is assembled to the assembly member, it is preferable that the frequency of vibration generated by the vibrator is different from the structural resonance frequency of the angular velocity sensor and the assembly member. When the member is connected via a solder bump, the structural resonance frequency is 50 to 60 kHz, and there is a problem that the degree of freedom in selecting the driving vibration frequency of the vibrator is low. Furthermore, when the angular velocity sensor and the assembly member are electrically and mechanically connected by solder bumps, there is a problem that the solder bumps are easily broken and have a short life because they have low thermal stress relaxation properties.

  In view of the above points, the present invention can increase the vibration resistance of a sensor chip compared to a conventional assembly structure of a mechanical quantity sensor when a mechanical quantity sensor having a sensor chip mounted on a package is connected to an assembly member. At the same time, it is an object of the present invention to provide an assembly structure of a mechanical quantity sensor capable of extending the life of a connection portion between the mechanical quantity sensor and the assembly member. It is another object of the present invention to provide an assembly structure of a mechanical quantity sensor that can improve the degree of freedom in selecting a driving vibration frequency of a vibrator when an angular velocity sensor is used as the mechanical quantity sensor.

  In order to achieve the above object, in the first aspect of the invention, the package (1) in which the sensor chip (7) and the circuit board (3) are mounted in the recess (2) is covered with the recess (2). In the assembly structure of the mechanical quantity sensor in which the mechanical quantity sensor (50) having the cover (11) is assembled to the assembly member (20), the recess (2) in the package (1) of the mechanical quantity sensor (50) is formed. One surface opposite to the mounted surface is mechanically connected to the assembly member (20) via the adhesive (15), and the mechanical quantity sensor (50) is supplied with power to the sensor chip (7) and the circuit board (3). Power supply means (13), and a circuit board (3) having a signal processing unit (5) and a radio unit (6), and output from the sensor chip (7) to the signal processing unit (5) When a physical quantity is detected from the received signal The wireless unit (6) transmits a signal indicating the detected physical quantity, and the wireless unit (6) transmits a signal indicating the physical quantity transmitted from the signal processing unit (5) to the outside of the mechanical quantity sensor (50). It is characterized by that.

  According to such an assembly structure of the mechanical quantity sensor, the power supplied to the circuit board (3) and the sensor chip (7) is supplied by the power supply means (13) and is detected by the sensor chip (7). Since the mechanical quantity is transmitted from the wireless unit (6) to the outside, the mechanical quantity sensor (50) and the assembly member (20) need only be considered mechanically connected. For this reason, a mechanical quantity sensor (50) and an assembly member are used by using an adhesive (15) having higher vibration absorption and higher thermal stress relaxation than solder bumps considering mechanical and electrical connections. The vibration-proof property with (20) can be improved, and the life of the connecting portion between the mechanical quantity sensor (50) and the assembly member (20) can be improved. Furthermore, when an angular velocity sensor is used as the mechanical quantity sensor (50), an adhesive (15) that takes into account only the mechanical connection of the structural resonance frequency between the angular velocity sensor and the assembly member (20) can be used. As a result, the degree of freedom in selecting the drive vibration frequency of the vibrator can be improved.

  For example, as in the invention described in claim 2, the adhesive (15) may be a silicone-based adhesive. According to such an assembly structure of the mechanical quantity sensor, the silicone-based adhesive has a higher vibration absorption than the solder bump and has a higher thermal stress relaxation property. The vibration can be increased and the life of the connecting portion can be extended. Furthermore, when an angular velocity sensor is used as the mechanical quantity sensor (50), the structural resonance frequency between the angular velocity sensor and the assembly member (20) can be set to 0.1 to 2 kHz. For this reason, even when the vibrator is driven to vibrate at 5 to 20 kHz and vibrations having a frequency that is an odd multiple of the driving vibration frequency are generated around the vibrator, this vibration is the structure of the angular velocity sensor and the assembly member (20). It is never close to the resonant frequency. Therefore, the degree of freedom in selecting the driving vibration frequency of the vibrator can be improved. In this case, as in the invention described in claim 3, a silicone-based gel that is a silicone-based adhesive can be used as the adhesive (15).

  Further, as in the invention described in claim 4, the signal processing unit (5) includes the excitation unit (52), and the excitation unit (52) determines whether or not the sensor chip (7) is abnormal. When it is determined that there is an abnormality in the sensor chip (7), a signal indicating that the sensor chip (7) is abnormal is transmitted to the wireless unit (6), and it is determined that there is no abnormality in the sensor chip (7). In this case, the sensor chip (7) is caused to perform a normal intermittent operation in which a detection operation for detecting a physical quantity and a stop operation for stopping the detection operation are alternately performed, and the sensor chip (7) The sensor chip (7) may be configured to perform the detection operation among the intermittent operations when the start signal for requesting the detection operation is received.

  Further, as in the invention described in claim 5, the mechanical quantity sensor (50) is mounted on the vehicle, the signal processing unit (5) is provided with the excitation unit (52), and the excitation unit (52) is a sensor chip ( 7) It is determined whether or not there is an abnormality. If it is determined that the sensor chip (7) is abnormal, a signal indicating that the sensor chip (7) is abnormal is transmitted to the wireless unit (6). When it is determined that there is no abnormality in the sensor chip (7), a detection operation for detecting a physical quantity and a stop operation for stopping the detection operation are alternately performed for the sensor chip (7). In addition, when the sensor chip (7) performs a normal intermittent operation, if a signal indicating that the vehicle is stopped is received, a detection operation is performed on the sensor chip (7) at a time rather than the normal intermittent operation. Long-term intermittent operation with a long stop operation time When a signal for starting the vehicle is received during operation, the sensor chip (7) is normally intermittently operated. When the vehicle is operating for a long period of time, the sensor chip is connected from the wireless unit (6). (7) When receiving a start signal for requesting a detection operation, or when receiving a start signal when a normal intermittent operation is performed, the sensor chip (7) is configured to perform a detection operation out of the intermittent operations. It is good.

  Further, as in the sixth aspect of the invention, the radio unit (6) is caused to receive a signal indicating a physical quantity from the signal processing unit (5), and the state of the excitation unit (52) is detected, so that the physical quantity is externally received. When it is determined that there is a signal for requesting a physical quantity, it is determined whether the excitation unit (52) is causing the sensor chip (7) to perform a detection operation. If the excitation unit (52) determines that the sensor chip (7) is not performing the detection operation, the start signal that causes the excitation unit (52) to perform the detection operation on the sensor chip (7). And when the excitation unit (52) determines that the sensor chip (7) is performing the detection operation, a signal indicating the physical quantity received from the signal processing unit (5) may be transmitted to the outside. .

  Further, as in the seventh aspect of the invention, when the excitation unit (52) determines whether or not the voltage supplied to the excitation unit (52) is reduced, the voltage is reduced. When the wireless unit (6) transmits a signal indicating that the voltage has dropped and the circuit of the excitation unit (52) has an abnormality, the wireless unit (6 ) Transmits a signal indicating that there is an abnormality in the circuit, and determines whether the sensor chip (7) has an abnormality by determining whether the sensor chip (7) has an abnormality. ) May transmit a signal indicating an abnormality of the sensor chip (7).

  Further, as in the invention described in claim 8, the signal processing section (5) and the radio section (6) may be separated by a trench.

  Moreover, you may comprise a cover (11) with a dielectric material like invention of Claim 9. Further, as in the invention described in claim 10, the cover (11) is made of a non-dielectric material and a plurality of through holes (15) are formed, and the circuit board (3) has an external portion of the mechanical quantity sensor (50). In addition, a transmission antenna (62) for transmitting a signal indicating a physical quantity may be provided, and a reception antenna (63) for receiving a signal requesting a physical quantity from the outside of the mechanical quantity sensor (50) may be provided.

  Further, as in the invention described in claim 11, the power supply means (13) is used as a coil, and an accommodation hole (11) that goes around the outside of the recess (2) is formed inside the package (1), and the accommodation hole A coil may be arranged in (11).

  Further, as in the invention described in claim 12, the coil (13) is placed on one side of the package (1) where the concave portion (2) is formed or on the opposite side of the one side where the concave portion (2) is formed. You may arrange in.

  Further, as in the invention described in claim 13, the adhesive (15) may be disposed on the outer edge of one surface of the mechanical quantity sensor (50) opposite to the one surface of the package.

  Further, as in the invention described in claim 14, a plurality of adhesives (15) are provided between one surface of the mechanical quantity sensor (50) opposite to one surface of the package (1) and the assembly member (20). The adhesives (15) arranged at a plurality of places may be arranged so as to be symmetrical with respect to the central axis of the mechanical quantity sensor (50).

  Further, as in the invention described in claim 15, the circuit board (3) and the sensor chip (7) are respectively connected to the bottom surface of the recess (2), and the wireless unit (6) is more than the signal processing unit (5). The circuit board (3) and the sensor chip (7) may be disposed so as to be separated from the vibrator.

  In addition, the code | symbol in the bracket | parenthesis of each means described in this column and the claim shows the correspondence with the specific means as described in embodiment mentioned later.

(First embodiment)
An assembly structure of an angular velocity sensor to which an embodiment of the present invention is applied will be described. FIG. 1 shows a cross-sectional view of the assembly structure of the angular velocity sensor according to the present embodiment, which will be described based on this drawing. Note that the angular velocity sensor of the present embodiment is used by being mounted on a vehicle, for example.

  As shown in FIG. 1, the angular velocity sensor 50 of this embodiment includes a package 1, and the package 1 is configured by laminating a plurality of ceramic layers such as alumina, for example. A recess 1 is formed on one surface of the package 1, and a circuit board 3 made of a semiconductor substrate is mounted on the bottom of the recess 2. Specifically, the circuit board 3 is bonded to the bottom surface of the recess 2 via, for example, a silicone adhesive 4.

FIG. 2 is a block diagram of the circuit board 3. As shown in FIG. 2, a signal processing unit 5 and a radio unit 6 are formed on the circuit board 3. The signal processing unit 5 and the radio unit 6 are separated by a trench, and noise propagates to each other. It is set as the structure which prevents that.
The signal processing unit 5 and the wireless unit 6 are electrically connected by a semiconductor wiring such as Al.

  The signal processing unit 5 includes a detection unit 51 and an excitation unit 52. The detection unit 51 includes a C / V conversion circuit (not shown). The detection unit 51 converts a capacitance change of the sensor chip 7 described later into a voltage signal by the C / V conversion circuit, and the converted signal indicates the angular velocity. To the wireless unit 6.

  The excitation unit 52 transmits a signal for driving the sensor chip 7 to the sensor chip 7, and when there is an abnormality in the sensor chip 7 or a circuit for driving the sensor chip 7, a signal indicating these abnormality is transmitted to the wireless unit 6. To send to. FIG. 3 shows a block diagram of the excitation unit 52. As shown in FIG. 3, the excitation unit 52 includes a control unit 52a, a drive 52b, and a first stage amplifier 52c.

  The control unit 52a transmits a signal for driving the sensor chip 7 to the drive 52b, and outputs a signal indicating an abnormality when there is an abnormality in the circuit for driving the sensor chip 7 or the sensor chip 7 provided in the excitation unit 52. This is transmitted to the wireless unit 6.

  The drive 52b drives the sensor chip 7 based on a signal from the control unit 52a. The first-stage amplifier 52c outputs an electrical signal (capacitance change) from the sensor chip 7 as a voltage signal by a C / V conversion circuit. Specifically, the sensor chip 7 is formed with a vibrator 8 and a drive electrode as will be described later, and outputs a voltage signal in accordance with a change in capacitance between the vibrator 8 and the drive electrode.

  As shown in FIG. 2, the wireless unit 6 includes a microcomputer 61, a transmission antenna 62, and a reception antenna 63. In the present embodiment, the transmission antenna 62 and the reception antenna 63 are provided on the circuit board 3 by pattern formation.

  The microcomputer 61 is a well-known device including a control unit 61a, a transmission unit 61b, and a reception unit 61c, and executes predetermined processing according to a program stored in a memory (not shown) in the control unit 61a.

  The control unit 61a functions to send a signal sent from the signal processing unit 5 to the transmission unit 61b. Further, for example, when the control unit 61a receives a signal requesting an angular velocity from an unillustrated ECU that performs predetermined processing according to the angular velocity from the reception unit 61c through the reception antenna 63, the excitation unit 52 causes the sensor chip 7 to Whether or not is driven is determined. When it is determined that the excitation unit 52 is driving the sensor chip 7, a signal indicating the detected angular velocity is transmitted to the ECU, and when it is determined that the excitation unit 52 is not driving the sensor chip 7. Transmits a start signal for driving the sensor chip 7 to the excitation unit 52.

  The transmission unit 61b functions as an output unit that transmits the signal transmitted from the control unit 61a to the ECU as a signal indicating the angular velocity through the transmission antenna 62.

  The receiving unit 61c functions as an input unit that receives a signal sent from the ECU through the receiving antenna 63 and sends the received signal to the control unit 61a.

  Further, as shown in FIG. 1, an adhesive portion for mounting the sensor chip 7 is provided on one surface of the circuit board 3 opposite to the one surface connected to the package 1, and the adhesive portion is provided with silicone. The sensor chip 7 is arranged via the system adhesive 9. The circuit board 3 and the sensor chip 7 are electrically connected via the wire bonding 10.

  The sensor chip 7 includes a detection element that detects angular velocity. Specifically, the sensor chip 7 has a base, a vibrator 8, a drive electrode, and a detection electrode.

  The vibrator 8 includes a comb tooth portion and a detection weight portion. In addition, the drive electrode is formed with a comb tooth portion, and the drive electrode is disposed so as to face the comb tooth portion formed on the vibrator 8. The detection electrode includes a first detection electrode and a second detection electrode, and the first detection electrode is arranged outside the detection weight portion formed on the vibrator 8. The second detection electrode is arranged at a position corresponding to the first detection electrode.

  In the sensor chip 7 of the present embodiment, the vibrator 8 is driven and oscillated in one direction at a predetermined frequency, and the vibrator 8 is orthogonal to the driving direction by Coriolis force generated when an angular velocity is applied to the vibrating vibrator 8. It is displaced in the direction to do. Then, since the interval between the detection weight portion and the detection electrode changes, a change in capacitance occurs in the sensor chip 7, and this change in capacitance is detected by the signal processing unit 5.

  A cover 11 made of a dielectric material such as ceramic is disposed on one surface of the package 1 where the recess 2 is formed so as to cover the recess 2.

  Further, a housing hole 12 that goes around the outside of the recess 2 is formed inside the package 1, and a coil 13 corresponding to the power supply means of the present invention and a capacitor (not shown) are arranged in the housing hole 12. The capacitor and the circuit board 3 are electrically connected by wire bonding 14. The accommodation hole 12 is formed by forming a through hole in a part of the plurality of ceramic layers constituting the package 1 and laminating the ceramic layers so as to communicate with the through hole.

  The coil 13 is for supplying electric power to the circuit board 3 and the sensor chip 7, receives electric wave transmission from a transceiver connected to the ECU, generates electric power by electromagnetic induction, and generates electric power. Is stored in a capacitor. In this case, the electromagnetic wave transmitted from the transceiver connected to the ECU to the coil has a sine wave rather than a rectangular wave in order to prevent noise propagation to the circuit board 3 and the sensor chip 7. Further, the frequency of the electromagnetic wave is preferably lower than the frequency of the signal transmitted from the wireless unit 6 to the ECU.

  In the present embodiment, the angular velocity sensor 50 is configured as described above, and one surface of the package 1 opposite to the surface on which the concave portion 2 is formed is provided with the adhesive 15 considering only mechanical connection to the substrate 20. Connected through. In the present embodiment, for example, a silicone-based adhesive is used as the adhesive 15, and the structural resonance frequency between the angular velocity sensor 50 and the substrate 20 is 0.1 to 2 kHz.

  Next, a basic detection operation of the angular velocity sensor 50 configured as described above will be described.

  First, the capacitance change according to the angular velocity occurs in the sensor chip 7, and the signal processing unit 5 converts the capacitance change of the sensor chip 7 into a voltage signal indicating the angular velocity and transmits the voltage signal to the wireless unit 6. The wireless unit 6 transmits the signal transmitted from the signal processing unit 5 to the ECU.

  Next, specific transmission means until a signal indicating the angular velocity is transmitted to the ECU will be described. First, the operation of the excitation unit 52 that drives the sensor chip 7 that detects the angular velocity will be described. FIG. 4 is a flowchart when the excitation unit 52 drives the sensor chip 7. In the present embodiment, when the ignition switch of the vehicle is turned on, the electric power generated by the electromagnetic induction of the coil 13 is used as a capacitor, and the electric power is supplied to the excitation unit 52. When the power is supplied from the capacitor, the excitation unit 52 starts the following process and repeats it at every predetermined calculation cycle.

  As shown in FIG. 4, in step 100, it is detected whether or not the sensor chip 7 operates normally. Specifically, when the drive vibration frequency for driving the vibrator 8 and the capacitance change between the vibrator 8 and the drive electrode do not correspond, it is determined that the vibrator 8 is abnormal.

  In step 110, when it is determined that the sensor chip 7 is abnormal, the process proceeds to step 120, and a signal indicating that the sensor chip 7 is abnormal is transmitted to the wireless unit 6. If it is determined that there is no abnormality in the sensor chip 7, the process proceeds to step 130.

  In step 130, the sensor chip 7 is caused to perform a normal intermittent operation in which a detection operation for detecting the angular velocity and a stop operation for stopping the detection of the angular velocity are alternately performed. The normal intermittent operation can be, for example, a detection operation for detecting an angular velocity for 0.1 seconds and a stop operation for stopping detection of an angular velocity for 0.1 seconds.

  Subsequently, in step 140, it is determined whether or not a start signal requesting the detection operation of the sensor chip 7 from the wireless unit 6 has been received. As will be described later, the start signal is transmitted from the wireless unit 6 when a signal requesting an angular velocity is transmitted from the ECU when the sensor chip 7 is in a stop operation state. Here, when the start signal is received, the process proceeds to step 130, and the sensor chip 7 is caused to perform the detection operation among the normal intermittent operations. If the start signal has not been received, the process ends. As will be described later, the start signal is transmitted from the wireless unit 6 when a signal requesting an angular velocity is transmitted from the ECU when the sensor chip 7 is in a stop operation state.

  Next, the operation of the wireless unit 6 that transmits a signal indicating the angular velocity to the ECU will be described. FIG. 5 is a flowchart when the wireless unit 6 transmits a signal indicating the angular velocity to the ECU. Similarly to the operation of the excitation unit 52, the operation of the wireless unit 6 is started based on the supply of power from the capacitor when the ignition switch of the vehicle is turned on, and is repeatedly performed every predetermined calculation cycle.

  As shown in FIG. 5, in step 200, a signal indicating the angular velocity is received from the detection unit 51 and a signal indicating the operation state of the sensor chip 7 from the excitation unit 52, that is, whether the sensor chip 7 is in the detection operation state. A signal indicating whether the operation is stopped is received.

  In step 210, it is determined whether or not there is a signal requesting angular velocity from the ECU. If it is determined that there is a signal requesting angular velocity, the process proceeds to step 220, and it is determined that there is no signal requesting angular velocity. If so, the process ends.

  In step 220, it is determined whether or not the excitation unit 52 is causing the sensor chip 7 to perform a detection operation out of the normal intermittent operations. Specifically, when the signal received from the excitation unit 52 in step 200 is a signal indicating the stop operation state of the sensor chip 7, the process proceeds to step 230, and the excitation operation is detected by the excitation unit 52 with respect to the sensor chip 7. Send a start signal to perform Then, in the excitation unit 52, a signal indicating the angular velocity is transmitted from the detection unit 51 to the wireless unit 6 in order to receive the start signal in step 140 and cause the sensor chip 7 to perform the detection operation. If the signal received from the excitation unit 52 is a signal indicating the detection operation of the sensor chip 7, the process proceeds to step 240, a signal indicating the angular velocity is transmitted to the ECU, and the process ends.

  As described above, in the angular velocity sensor 50 according to the present embodiment, the excitation unit 52 determines whether or not the sensor chip 7 has an abnormality. When the sensor chip 7 has no abnormality, the sensor chip 7 detects and stops. A normal intermittent operation is performed in which the operations are alternately performed.

The wireless unit 6 receives a signal indicating the angular velocity detected by the sensor chip 7 via the detection unit 51, and determines whether a signal requesting the angular velocity is received from the ECU. When the signal requesting the angular velocity is received from the ECU, it is determined whether or not the excitation unit 52 is causing the sensor chip 7 to perform the detection operation. Then, a signal indicating the angular velocity is transmitted and the process is terminated. In addition, when the excitation unit 52 does not cause the sensor chip 7 to perform the detection operation, a start signal that causes the excitation unit 52 to perform the detection operation of the sensor chip 7 is transmitted.

  When the excitation unit 52 receives the start signal, the sensor unit 7 causes the sensor chip 7 to perform a detection operation out of the normal intermittent operation. Therefore, a signal indicating the angular velocity is transmitted from the sensor chip 7 to the wireless unit 6 via the detection unit 51. Will be. When receiving the signal indicating the angular velocity after transmitting the start signal, the wireless unit 6 determines that the excitation unit 52 is causing the sensor chip 7 to perform a detection operation, and transmits the signal indicating the angular velocity to the ECU for processing. finish.

  Further, in this embodiment, the control unit provided in the excitation unit 52 has no power supply voltage drop or abnormality in the circuit of the excitation unit 52 other than whether or not the sensor chip 7 operates normally. Judgment is made. FIG. 6 is a flowchart of the abnormality determination means of the control unit 52a provided in the excitation unit 52, and is performed at predetermined intervals.

  As shown in FIG. 6, in step 300, it is determined whether or not the power supply voltage supplied from the capacitor has dropped. Specifically, a threshold is set in the control unit 52a, and when the voltage supplied from the capacitor is lower than the threshold, it is determined that the voltage of the capacitor has decreased. For this reason, if a negative determination is made in step 300, the process proceeds to step 310, a signal indicating that the voltage supplied from the capacitor is low is transmitted to the wireless unit 6, and the process ends. If an affirmative determination is made in step 300, the process proceeds to step 320.

  In step 320, it is determined whether or not the voltage of the drive 52b has dropped. Specifically, when the voltage supplied from the capacitor has not decreased but the voltage of the drive 52b has decreased, it is determined that there is an abnormality in the circuit that drives the sensor chip 7. Therefore, if a negative determination is made in step 320, the process proceeds to step 330. In step 330, a signal indicating that there is an abnormality in the circuit is transmitted to the wireless unit 6, and the process is terminated. If an affirmative determination is made in step 320, the process proceeds to step 340.

  In step 340, it is determined whether or not there is an abnormality in the output of the first stage amplifier 52c. Specifically, when the voltage supplied from the capacitor and the voltage of the drive 52b are not lowered but the signal output from the first stage amplifier 52c is abnormal, it is determined that the vibrator 8 is abnormal. For this reason, if a negative determination is made in step 340, the process proceeds to step 350, a signal indicating abnormality of the vibrator 8 is transmitted to the wireless unit 6, and the process ends. It should be noted that it is determined that there is an abnormality in the vibrator 8 in the same manner as in step 100 described above, because the drive vibration frequency for driving the vibrator 8 and the capacitance change between the vibrator 8 and the drive electrode correspond. If not, it is determined that the vibrator 8 is abnormal. If an affirmative determination is made in step 340, the process ends.

  If it is determined that there is an abnormality in the output of the first-stage amplifier 52c, the process proceeds to 350, and if it is determined that there is no abnormality, the process is terminated. In step 350, it is determined that there is an abnormality in the vibrator 8, and a signal for transmitting the abnormality of the vibrator 8 is transmitted to the wireless unit 6. Specifically, when the drive vibration frequency for driving the vibrator 8 does not correspond to the capacitance change between the vibrator 8 and the drive electrode, it is determined that the vibrator 8 is abnormal.

  According to such an assembly structure of the angular velocity sensor, the electric power supplied to the circuit board 3 and the sensor chip 7 uses electric power generated by electromagnetic induction between the transmitter / receiver connected to the ECU and the coil 13, and Since the angular velocity detected by the sensor chip 7 is transmitted from the wireless unit 6 to the ECU by wireless communication, the connection between the angular velocity sensor 50 and the substrate 20 need only consider mechanical connection. In other words, in the present embodiment, the adhesive 15 considering only mechanical connection can be used, and vibration absorption is higher and thermal stress relaxation than conventional solder bumps considering mechanical and electrical connection. A high adhesive 15 can be used. For this reason, vibration isolation between the mechanical quantity sensor 50 and the substrate 20 can be improved, and the life of the connecting portion between the angular velocity sensor 50 and the substrate 20 can be extended.

  In this embodiment, a silicone-based adhesive is used as the adhesive 15 having higher vibration absorption and higher thermal stress relaxation than conventional solder bumps, and the structural resonance frequency between the angular velocity sensor 50 and the substrate 20 is high. 0.1 to 2 kHz. For this reason, even when the vibration frequency generated around the vibrator 8 is 50 to 60 kHz, the vibration frequency of the vibrator 8 is different from the structural resonance frequency between the angular velocity sensor 50 and the substrate 20. The vibration of the angular velocity sensor 50 due to the generation of the sensor chip 7 can be prevented, and the vibration isolating property of the sensor chip 7 can be improved. Furthermore, since it is possible to select the drive vibration frequency of the vibrator 8 at which the frequency of the vibration generated around is 50 to 60 kHz, the degree of freedom in selecting the drive vibration frequency of the vibrator 8 can also be improved.

  Further, when the wireless unit 6 receives a signal requesting the angular velocity from the ECU, the wireless unit 6 transmits a signal indicating the angular velocity detected by the sensor chip 7 to the ECU, so that power consumption can be suppressed. Furthermore, since the sensor chip 7 detects the angular velocity by the normal intermittent operation, the power consumption can be suppressed.

(Second Embodiment)
A second embodiment of the present invention will be described. The assembly structure of the angular velocity sensor of the present embodiment is obtained by changing the operation of the excitation unit 52 with respect to the first embodiment, and the other parts are the same as those of the first embodiment, and thus the description thereof is omitted here. FIG. 7 is a flowchart when the excitation unit 52 drives the sensor chip 7, and is performed every predetermined calculation cycle.

  As shown in FIG. 7, in steps 400 to 430, as in steps 100 to 130 described in the first embodiment, it is determined whether or not there is an abnormality in the sensor chip 7. If there is an error, a signal indicating that the sensor chip 7 is abnormal is transmitted to the wireless unit 6. If the sensor chip 7 is not abnormal, the sensor chip 7 is normally intermittently operated.

  In step 440, it is determined whether or not the vehicle is stopped. If it is determined that the vehicle is stopped, the process proceeds to step 450. If it is determined that the vehicle is not stopped, the process proceeds to step 470. . Specifically, when the vehicle stops, a signal indicating that the vehicle has stopped is transmitted from the ECU to the excitation unit 52 via the wireless unit 6. Therefore, the excitation unit 52 determines that the vehicle is stopped when the signal is received, and determines that the vehicle is not stopped when the signal is not received.

  In step 450, the sensor chip 7 is caused to perform a long-term intermittent operation in which the detection operation and the stop operation that are performed once are longer than the normal intermittent operation in step 430. As this long-term intermittent operation, for example, a detection operation for detecting an angular velocity for one second and a stop operation for stopping an angular velocity detection operation for one second can be used.

  In step 460, it is determined whether or not the vehicle has started. If it is determined that the vehicle has started, the process proceeds to step 430. If it is determined that the vehicle has not been started, the process proceeds to step 470. Specifically, when the vehicle starts, a signal indicating that the vehicle has started is transmitted from the ECU to the excitation unit 52 via the wireless unit 6. Therefore, when receiving this signal, the excitation unit 52 determines that the vehicle has started, and proceeds to step 430. Otherwise, the excitation unit 52 determines that the vehicle has not been started and proceeds to step 470.

  In step 470, as in step 140 described above, it is determined whether or not a start signal from the wireless unit 6 has been received. If it is determined that the start signal has been received, the process proceeds to step 430 to detect normal intermittent operation. The sensor chip 7 is operated. If the start signal has not been received, the process ends.

  In such an assembly structure of the angular velocity sensor, the angular velocity sensor 50 and the substrate 20 are not electrically connected, and the angular velocity sensor 50 is operated by the electric power stored in the capacitor. For this reason, in this embodiment, the electric power stored in the capacitor is limited, and since the angular velocity is difficult to be applied to the vehicle while the vehicle is stopped, excitation is performed when the vehicle is stopped. The unit 52 causes the sensor chip 7 to perform a long-term intermittent operation in which the detection operation and the stop operation that are performed at once are longer than the normal intermittent operation. Therefore, it is possible to detect the angular velocity while suppressing the power consumption while the vehicle is stopped while obtaining the same effect as the first embodiment.

(Third embodiment)
A third embodiment of the present invention will be described. The assembly structure of the angular velocity sensor of the present embodiment is obtained by changing the arrangement part of the adhesive 15 with respect to the first embodiment, and the other parts are the same as those of the first embodiment, and thus the description thereof is omitted here. FIG. 8 is an overall cross-sectional view of the assembly structure of the angular velocity sensor according to the present embodiment.

  As shown in FIG. 8, the assembly structure of the angular velocity sensor of the present embodiment is a structure in which the adhesive 15 is disposed on the outer edge portion of one surface of the angular velocity sensor 50 opposite to the surface on which the concave portion of the package 1 is formed. It is said that. According to such an assembly structure of the angular velocity sensor, since the amount of the adhesive 15 disposed between the angular velocity sensor 50 and the substrate 20 can be reduced as compared with the first embodiment, the same as in the first embodiment. While obtaining the above effect, the generation of thermal stress between the angular velocity sensor 50 and the substrate 20 can be reduced from the first embodiment, and the life of the connecting portion between the angular velocity sensor 50 and the substrate 20 can be extended.

(Fourth embodiment)
A fourth embodiment of the present invention will be described. The assembly structure of the angular velocity sensor according to the present embodiment is obtained by changing the material of the cover 11 to metal with respect to the first embodiment, and the other parts are the same as those of the first embodiment, and thus the description thereof is omitted here. FIG. 9 is an overall cross-sectional view of the assembly structure of the angular velocity sensor according to the present embodiment.

  In this embodiment, the cover 12 is made of a non-dielectric metal, and when the cover 11 is disposed so as to cover the recess 2 formed in the package 1, the ECU, the transmission antenna 62, and the reception antenna 63 are arranged. Wireless communication with cannot be performed. For this reason, in this embodiment, as shown in FIG. 9, a through hole 15 is formed in the cover 11 so that wireless communication between the ECU and the transmission antenna 62 and the reception antenna 63 can be performed.

  Further, since the cover 11 is made of a dielectric material, a plurality of through holes 15 are formed in the cover 11 in order to prevent noise generated by driving the vibrator 8 from being reflected in the cover. Has been.

  Since foreign matter such as dust may be introduced from the through-hole 15 into the package 1, the sensor chip 7 is face-down and electrically connected to the circuit board 3 via the solder bumps 9 and the like. . Even with such an assembly structure of the angular velocity sensor, the same effect as in the first embodiment can be obtained.

(Other embodiments)
In each of the above-described embodiments, an example in which the angular velocity sensor 50 is connected to the substrate 20 using a silicone-based adhesive as the adhesive 15 has been described. However, as the adhesive 15, for example, an angular velocity using a silicone gel is used. The sensor 50 and the substrate 20 may be connected. In this case, the structural resonance frequency between the angular velocity sensor 50 and the substrate 20 depends on the elastic modulus of the silicone gel and can be set to 0.1 to 0.2 kHz.

  Moreover, in each said embodiment, although it is set as the structure which has arrange | positioned the coil 13 inside the package 1, you may arrange | position outside the package 1, for example, it is good also as a structure arrange | positioned on the surface of the cover 11. FIG.

  Further, in each of the above embodiments, the sensor chip 7 is mounted on the circuit board 3 and disposed in the package 1. However, the circuit board 3 and the sensor chip 7 may be connected to the bottom surface of the recess 2 respectively. Good. Further, in the case of such an assembly structure of the angular velocity sensor 50, the circuit board 3 and the sensor chip 7 are arranged so that the wireless unit 6 is separated from the vibrator 8 provided in the sensor chip 7 rather than the signal processing unit 5. It is preferable to arrange.

  In the third embodiment, the angular velocity sensor 50 and the substrate 20 are connected via the adhesive 15 disposed on the outer edge of the package 1. For example, a plurality of adhesives 15 are attached to the package 1. You may arrange | position so that it may become symmetrical with respect to a central axis.

  Furthermore, although the transmission antenna 62 and the reception antenna 63 are provided on the circuit board 3 in the first embodiment, for example, the transmission antenna 62 and the reception antenna 63 may be arranged on the side surface of the package 1. In this case, for example, a wiring is formed on the surface of the ceramic layer constituting the package 1, and the transmission antenna 62 and the reception antenna 63 are electrically connected to the transmission unit 61b and the reception unit 61c via the wiring. It is good. In the fourth embodiment, the transmitting antenna 62 and the receiving antenna 63 may be arranged on the side surface of the package 1. In this case, since there is no obstacle that interferes with wireless communication between the ECU and the transmission antenna 62 and the reception antenna 63, the through hole 15 may not be formed in the cover 11.

  In each of the above-described embodiments, the angular velocity sensor 50 is described as an example of the mechanical quantity sensor. However, it can be applied to a sensor that detects other physical quantities, and can be used for an acceleration sensor, for example. .

  Further, in each of the above embodiments, the configuration has been described in which the radio unit 6 transmits a signal indicating the angular velocity to the ECU when receiving a signal requesting the angular velocity from the ECU. However, as a configuration in which all the detected angular velocities are transmitted to the ECU. Also good.

It is a figure which shows the cross-sectional structure of the assembly | attachment structure of the angular velocity sensor concerning 1st Embodiment of this invention. It is a figure which shows the block diagram of the circuit board shown in FIG. It is a figure which shows the block diagram of the excitation part shown in FIG. It is a flowchart at the time of the excitation part shown in FIG. 2 driving a sensor chip. It is a flowchart when the radio | wireless part shown in FIG. 2 sends the signal which shows angular velocity to ECU. It is a flowchart about the abnormality determination means of the control part with which the excitation part shown in FIG. 2 was equipped. It is a flowchart at the time of the excitation part concerning 2nd Embodiment of this invention driving a sensor chip. It is a figure which shows the cross-sectional structure of the assembly structure of the angular velocity sensor concerning 3rd Embodiment of this invention. It is a figure which shows the cross-sectional structure of the assembly structure of the angular velocity sensor concerning 4th Embodiment of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Package 2 Concave part 3 Circuit board 5 Signal processing part 6 Radio | wireless part 7 Sensor chip 8 Vibrator 11 Cover 13 Coil 15 Adhesive 20 Board | substrate 50 Angular velocity sensor 51 Detection part 52 Excitation part

Claims (15)

A sensor chip (7) for outputting an electrical signal in accordance with the applied physical quantity;
A circuit board (3) for detecting the physical quantity from the signal output from the sensor chip (7);
A package (1) having a recess (2) on one surface and mounting the sensor chip (7) and the circuit board (3) on the recess (2);
A mechanical quantity sensor (50) having a cover (11) arranged so as to cover the recess (2) on the one surface of the package (1); In the assembly structure,
One surface of the mechanical quantity sensor (50) opposite to the one surface of the package (1) is mechanically connected to the assembly member (20) via an adhesive (15),
The mechanical quantity sensor (50) includes a power supply means (13) for supplying power to the sensor chip (7) and the circuit board (3).
The circuit board (3) is configured to include a signal processing unit (5) and a radio unit (6) that operate by receiving power supply from the power supply unit (13). 5) detects the physical quantity from the signal output from the sensor chip (7) and transmits a signal indicating the detected physical quantity to the radio unit (6), and the radio unit (6) An assembly structure of a mechanical quantity sensor, wherein the signal indicating the physical quantity transmitted from the signal processing unit (5) is transmitted to the outside of the mechanical quantity sensor (50) by wireless communication.   The mechanical quantity sensor assembly structure according to claim 1, wherein the adhesive (15) is a silicone-based adhesive.   The assembly structure of a mechanical quantity sensor according to claim 1 or 2, wherein the adhesive (15) is composed of a silicone-based gel that is the silicone-based adhesive.   The signal processing unit (5) includes an excitation unit (52), and the excitation unit (52) determines whether the sensor chip (7) has an abnormality, and the sensor chip (7) has an abnormality. When it is determined that there is an abnormality, a signal indicating that the sensor chip (7) is abnormal is transmitted to the wireless unit (6), and when it is determined that there is no abnormality in the sensor chip (7), the sensor A normal intermittent operation in which a detection operation for detecting the physical quantity and a stop operation for stopping the detection operation are alternately performed on the chip (7), and the sensor chip (7) from the wireless unit (6) is performed. The mechanical quantity according to any one of claims 1 to 3, wherein when the start signal for requesting the detection operation is received, the sensor chip (7) is caused to perform the detection operation among the intermittent operations. Sensor assembly structure. The mechanical quantity sensor (50) is mounted on a vehicle,
The signal processing unit (5) includes an excitation unit (52),
The excitation unit (52) determines whether or not the sensor chip (7) has an abnormality. When the excitation unit (52) determines that the sensor chip (7) has an abnormality, the wireless unit (6) receives the sensor. A detection operation for transmitting a signal indicating that the chip (7) is abnormal and detecting the physical quantity to the sensor chip (7) when it is determined that the sensor chip (7) is normal. When the normal intermittent operation is performed alternately with the stop operation for stopping the detection operation and the normal intermittent operation is performed by the sensor chip (7), a signal indicating that the vehicle is stopped is received. Then, the sensor chip (7) is caused to perform a long-term intermittent operation in which the detection operation and the stop operation that are performed at a time longer than the normal intermittent operation are performed. When letting When the signal for starting the vehicle is received, the wireless intermittent operation is performed when the sensor chip (7) performs the normal intermittent operation and the sensor chip (7) performs the long-term intermittent operation. When the start signal for requesting the detection operation of the sensor chip (7) is received from (6), or when the start signal is received during the normal intermittent operation, the sensor chip (7) The assembly structure of the mechanical quantity sensor according to any one of claims 1 to 3, wherein the detection operation is performed among the intermittent operations.   The radio unit (6) receives a signal indicating the physical quantity from the signal processing unit (5), detects an operating state of the excitation unit (52), and externally transmits the signal from the mechanical quantity sensor (50). When it is determined whether there is a signal requesting a physical quantity and it is determined that there is a signal requesting the physical quantity, the excitation unit (52) causes the sensor chip (7) to perform the detection operation. If the excitation unit (52) determines that the sensor chip (7) is not performing the detection operation, the start signal is sent to the excitation unit (52). And when the excitation unit (52) determines that the sensor chip (7) is performing the detection operation, a signal indicating the physical quantity received from the signal processing unit (5) is transmitted as the mechanical quantity. Specially sent to outside of sensor (50) Assembly structure of a physical quantity sensor according to claim 4 or 5,.   The excitation unit (52) determines whether or not the voltage supplied to the excitation unit (52) has decreased. If the excitation unit (52) determines that the voltage has decreased, the wireless unit (6) To determine whether there is an abnormality in the circuit that drives the sensor chip (7) provided in the excitation unit (52). When it is determined that there is an abnormality, a signal indicating that there is an abnormality in the circuit is transmitted to the wireless unit (6), and it is determined whether there is an abnormality in the sensor chip (7). The signal indicating that there is an abnormality in the sensor chip (7) is transmitted to the wireless unit (6) when it is determined that there is an abnormality in the chip (7). An assembly structure of the mechanical quantity sensor according to claim 1.   The assembly structure of the mechanical quantity sensor according to any one of claims 1 to 7, wherein the signal processing unit (5) and the wireless unit (6) are separated by a trench.   The mechanical quantity sensor assembly structure according to any one of claims 1 to 8, wherein the cover (11) is made of a dielectric.   The cover (11) is made of a non-dielectric material and has a plurality of through holes (15). The circuit board (3) shows the physical quantity outside the mechanical quantity sensor (50). A transmission antenna (62) for transmitting a signal is provided, and a reception antenna (63) for receiving a signal requesting the physical quantity from the outside of the mechanical quantity sensor (50) is provided. The assembly structure of a mechanical quantity sensor according to any one of claims 1 to 8, characterized in that:   The power supply means (13) is a coil, and an accommodation hole (11) is formed inside the package (1) around the outside of the recess (2), and the coil is placed in the accommodation hole (11). The assembly structure of the mechanical quantity sensor according to any one of claims 1 to 10, wherein the structure is arranged.   The said power supply means (13) is a coil, The said coil (13) is arrange | positioned on the said surface of the said package (1), or one surface opposite to the said surface, The 1 thru | or 10 characterized by the above-mentioned. The assembly structure of the mechanical quantity sensor as described in any one of these.   13. The adhesive (15) according to any one of claims 1 to 12, wherein the adhesive (15) is disposed on an outer edge of one surface of the mechanical quantity sensor (50) opposite to the one surface of the package. Assembly structure of the described mechanical quantity sensor.   The adhesive (15) is disposed at a plurality of locations between one surface of the mechanical quantity sensor (50) opposite to the one surface of the package (1) and the assembly member (20). 14. The adhesive (15) arranged at a location is arranged so as to be symmetric with respect to the central axis of the mechanical quantity sensor (50), respectively. The assembly structure of the mechanical quantity sensor described in 1.   A vibrator is formed on the sensor chip (7), the circuit board (3) and the sensor chip (7) are connected to the bottom surface of the recess (2), and the radio unit (6) is connected to the sensor chip (7). The circuit board (3) and the sensor chip (7) are arranged so as to be farther from the vibrator than the signal processing unit (5). Assembly structure of the described mechanical quantity sensor.

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