JP5320862B2 - Sensor device - Google Patents

Description

  The present invention relates to a sensor device including two gyro sensors arranged on the same axis of angular velocity detection.

  Conventionally, for example, Patent Literature 1 proposes an inertial sensor unit including a pair of inertial sensors that detect acceleration or angular velocity as an inertial force of a detection target. Specifically, Patent Document 1 proposes an inertial sensor unit that is arranged so as to detect an inertial force in the same direction and includes inertial sensors having the same structure and arranged on the same axis.

With such an arrangement of each inertial sensor, the output value of each inertial sensor is added, so that the signal is doubled, the noise is doubled, and the resolution of the inertial sensor unit can be improved. Yes.
JP 2005-106727 A

  However, in the above conventional technique, although the resolution of the inertial sensor unit can be improved, if external disturbance noise is added to each inertial sensor, the disturbance noise is detected by each inertial sensor, and the disturbance noise is doubled by the route and output. Therefore, the S / N ratio does not change.

  An object of this invention is to provide the sensor apparatus which can reduce the influence by disturbance noise in view of the said point.

In order to achieve the above object, according to the first aspect of the present invention, an axis extending in one direction is an x axis, an axis perpendicular to the x axis is a y axis, and an axis perpendicular to the x axis and the y axis is a z axis. As shown in the figure, a drive unit (15) that vibrates in the x-axis direction, a detection weight (11) coupled to the drive unit (15) so as to be displaced in the y-axis direction, and a detection weight (11) A first movable electrode (13) that is displaced in the axial direction and a first fixed electrode (14) that is disposed to face the first movable electrode (13). In the first movable electrode (13), in the y-axis direction. A capacitive first gyro that detects an angular velocity about the z-axis based on a change in capacitance between the first movable electrode (13) and the first fixed electrode (14) when a displacement of force due to Coriolis force occurs. Sensor (10), drive unit (25) that vibrates in the x-axis direction, and drive to displace in the y-axis direction A combined detector weights (25) (21), the detector weights (21
) And a second movable electrode (23) that is displaced in the y-axis direction, and a second fixed electrode (24) disposed opposite to the second movable electrode (23). A capacity for detecting an angular velocity around the z-axis based on a change in capacity between the second movable electrode (23) and the second fixed electrode (24) when a displacement of force due to the Coriolis force occurs in the y-axis direction in FIG. The first gyro sensor (10) and the second gyro sensor (20) have the same structure, and the first gyro sensor (10) and the second gyro sensor (20). ) Are stacked on the z axis as the same detection axis, and when an angular velocity is applied to each of the first gyro sensor (10) and the second gyro sensor (20), the first gyro sensor (10) 1 movable electrode (13 When the second second movable electrode of the gyroscope (20) (23), characterized in that the displacement in the opposite direction in the y-axis direction. Furthermore, a first cap (93) is stacked on the surface of the first gyro sensor (10) where the first movable electrode (13) is provided, and the second movable electrode (23) of the second gyro sensor (20). The second cap (94) is laminated on the surface on which the circuit chip is provided, and the circuit chip (95) is sandwiched between the second cap (94) and the first gyro sensor (10). And

  According to this, since the angular velocity component detected by the second gyro sensor (20) is an angular velocity component that appears in a phase opposite to that detected by the first gyro sensor (10), the first gyro sensor (10 ) And the second gyro sensor (20), the noise included in each output can be canceled out. Therefore, it is possible to reduce the influence of disturbance noise applied to the sensor device from the outside.

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

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the following embodiments, the same or equivalent parts are denoted by the same reference numerals in the drawings.

(First embodiment)
Hereinafter, a first embodiment of the present invention will be described with reference to the drawings. The sensor device shown in the present embodiment is mounted on a vehicle, and is used, for example, for detecting a side slip of the vehicle and performing a control for preventing a side slip.

  FIG. 1 is a configuration diagram of first and second gyro sensors used in the sensor device according to the present embodiment. First, an axis extending in one direction is an x axis, an axis perpendicular to the x axis is a y axis, and an axis perpendicular to the x axis and the y axis is a z axis.

  As shown in FIG. 1, the first gyro sensor 10 includes a detection weight 11, detection electrodes 13 and 14, a drive frame 15, a drive beam 16, a detection beam 17, and a fixing portion 18. .

  Specifically, the first gyro sensor 10 has a drive frame 15 that vibrates the entire vibrator at a constant frequency and a constant amplitude, such as an electrostatic force, which is vibrated in the x-axis direction by the fixed portion 18 and the drive beam 16. Supported as possible.

  The detection weight 11 is coupled to the drive frame 15 via the detection beam 17 and is supported so as to be displaceable in the y-axis direction. When the drive frame 15 is driven to vibrate in the x-axis direction by drive means (not shown), if an angular velocity with the z-axis as the rotation axis is applied, Coriolis proportional to the velocity that vibrates in the y-axis direction is applied. Force acts. That is, the displacement of the force due to the Coriolis force occurs in the y-axis direction in the detection movable electrode 13.

  Since the detection weight 11 can be displaced in the y-axis direction, it is displaced in the y-axis direction according to the Coriolis force. The detection weight 11 is provided with a detection movable electrode 13, and a detection fixed electrode 14 is provided so as to face the detection movable electrode 13. When the detection movable electrode 13 is displaced in the y-axis direction due to the displacement of the detection weight 11, the relative distance between the electrodes 13 and 14 changes, and the capacitance also changes accordingly. By detecting the change in the capacitance, the angular velocity that appears due to the Coriolis force is detected.

However, the detection weight 11 is displaced not only by the Coriolis force but also when an acceleration having a y-axis direction component is applied, and a capacitance change is generated.

  The second gyro sensor 20 has the same configuration as the first gyro sensor 10. That is, the detection weight 11, the detection movable electrode 13, the detection fixed electrode 14, the drive frame 15, the drive beam 16, the detection beam 17, and the detection weight 21, the detection movable electrode 23 corresponding to the fixed portion 18 of the first gyro sensor 10, and the detection. A fixed electrode 24, a drive frame 25, a drive beam 26, a detection beam 27, and a fixed portion 28 are provided.

  When an angular velocity is applied to each of the first gyro sensor 10 and the second gyro sensor 20, the first movable electrode 13 of the first gyro sensor 10 and the second movable electrode 23 of the second gyro sensor 20 are in the y-axis direction. In the opposite direction.

  FIG. 2 is a schematic diagram of the arrangement of the gyro sensors 10 and 20. As shown in this figure, the gyro sensor 10 and the gyro sensor 20 equivalent thereto are arranged so that the drive direction x and the detection direction y are the same direction, and the z axis is a common axis. The These two gyro sensors 10 and 20 have the drive frequencies of the drive frames 15 and 25 the same and vibrate in opposite phases.

  The arithmetic circuit 30 inputs an output including an acceleration signal component as disturbance noise applied from the outside to the first gyro sensor 10 from the first gyro sensor 10, and from the second gyro sensor 20 to the second gyro sensor 20. An output including an acceleration signal component added from the outside is input to 20 and an operation for removing the acceleration signal component is performed based on each output. The arithmetic circuit 30 is provided on the printed circuit board 40 shown in FIG. 2 or is mounted on the printed circuit board 40 as a processing chip.

  Specifically, the arithmetic circuit 30 calculates the difference between the capacitance change signals output from the gyro sensors 10 and 20. Since the detection direction and the drive direction are aligned and driven with the same drive frequency and opposite phase, the displacement due to the Coriolis force of the detection weight 11 is in the opposite phase, and the displacement due to the acceleration not due to the drive vibration is in the same phase. Occur. That is, by taking the difference between these signals, the in-phase component can be removed and only the Coriolis force component can be extracted.

  FIG. 3 is an overall schematic diagram of the sensor device 1. As shown in FIG. 3, the first gyro sensor 10 and the second gyro sensor 20 shown in FIG. 1 actually have a laminated structure. The laminated product is fixed to the printed circuit board 40. The printed circuit board 40 corresponds to the substrate of the present invention.

  The above is the overall configuration of the sensor device 1 according to the present embodiment. In the present embodiment, when the respective gyro sensors 10 and 20 stacked as shown in FIG. 3 are mounted on the printed board 40, the x-axis and the y-axis shown in FIG. The z axis is arranged perpendicular to the plane of the printed circuit board 40.

  Next, the operation for detecting the angular velocity in the sensor device 1 will be described. As described above, in each of the gyro sensors 10 and 20, the relative distance between the detection movable electrodes 13 and 23 and the detection fixed electrodes 14 and 24 is changed by the displacement of the detection weights 11 and 21 according to the Coriolis force. To do. That is, a displacement of force due to the Coriolis force occurs in the y-axis direction in the detection movable electrodes 13 and 23, respectively. At this time, the detection movable electrode 13 of the first gyro sensor 10 and the detection movable electrode 23 of the second gyro sensor 20 are displaced in opposite directions in the y-axis direction. Capacitance corresponding to the change in the relative distance is input from the gyro sensors 10 and 20 to the arithmetic circuit 30.

  And the detection direction of each gyro sensor 10 and 20 and a drive direction are the same directions, and it drives with the same drive frequency and a reverse phase. That is, the electrostatic capacity signal input from the gyro sensors 10 and 20 to the arithmetic circuit 30 is in reverse phase with respect to the displacement caused by the Coriolis force of the detection weights 11 and 21, and the displacement due to the acceleration not caused by the drive vibration. It is in phase.

  Therefore, the arithmetic circuit 30 calculates a difference between signals input from the gyro sensors 10 and 20. Thereby, the in-phase component, that is, the displacement due to the acceleration not depending on the driving vibration is removed, and only the Coriolis force component, that is, the displacement caused by the Coriolis force of the detection weights 11 and 21 is extracted. In this way, an angular velocity component from which acceleration is removed can be obtained.

  In addition, the acceleration can be obtained by performing a calculation for removing the angular velocity component by the same calculation.

  As described above, each of the first gyro sensor 10 and the second gyro sensor 20 is arranged on the same z-axis. Further, when an angular velocity is applied to each of the gyro sensors 10 and 20, the detection movable electrode 13 of the first gyro sensor 10 and the detection movable electrode 23 of the second gyro sensor 20 are displaced in opposite directions in the y-axis direction. Is a feature.

  Therefore, the arithmetic circuit 30 can perform an operation for canceling the acceleration signal component by taking the differential of the outputs of the first gyro sensor 10 and the second gyro sensor 20. In this way, the influence of the acceleration signal component from the outside on the sensor device 1 can be reduced.

  As for the correspondence between the description of the present embodiment and the description of the claims, the drive frame 15 corresponds to the first drive unit of the claims, and the drive frame 25 corresponds to the second drive of the claims. Corresponding to the part. The detection movable electrode 13 corresponds to the first movable electrode in the claims, and the detection movable electrode 23 corresponds to the second movable electrode in the claims.

(Second Embodiment)
In the present embodiment, only different parts from the first embodiment will be described. In each of the above embodiments, as shown in FIG. 2, the gyro sensors 10 and 20 are stacked. However, the present embodiment is characterized in that the stacked structure is housed in a case via a vibration isolation member. It has become.

  FIG. 4 is a schematic sectional view in which the gyro sensors 10 and 20 are mounted on the printed circuit board 40 in the present embodiment. As shown in this figure, the printed circuit board 40 is provided with a case 70 having a hollow portion. The case 70 is formed of, for example, a resin, and a cylindrical shape having a hollow portion as shown in FIG. 4 is preferable.

  The laminated structure of the gyro sensors 10 and 20 includes a vibration isolating member 80 between the inner wall surface of the case 70 and the first gyro sensor 10 and between the inner wall surface of the case 70 and the second gyro sensor 20. By being arranged, it is housed in the hollow part of the case 70. As the vibration isolation member 80, for example, a rubber member is employed.

  As described above, by fixing the laminated structure with the vibration isolation member 80, the influence of vibration can be reduced, and the detection accuracy of each of the gyro sensors 10 and 20 can be improved.

(Third embodiment)
FIG. 5 is a schematic cross-sectional view in which the gyro sensors 10 and 20 are mounted on the printed circuit board 40 in the present embodiment. As shown in this figure, the printed circuit board 40 is sandwiched between the first gyro sensor 10 and the second gyro sensor 20. Even in such an arrangement, the gyro sensors 10 and 20 can be arranged on the same axis.

(Fourth embodiment)
In the present embodiment, only different parts from the first embodiment will be described. FIG. 6 is a cross-sectional view of the laminated structure of the gyro sensors 10 and 20 according to the present embodiment. As shown in this figure, a laminated structure in which a plate member 41 is sandwiched between the first gyro sensor 10 and the second gyro sensor 20 is formed. As such a plate member 41, for example, a vibration isolating member can be used. Thereby, it is possible to further reduce the influence of vibration in each of the gyro sensors 10 and 20.

  The laminated structure shown in FIG. 6 can be mounted on the printed circuit board 40 as shown in FIG.

(Fifth embodiment)
In the present embodiment, only different parts from the first embodiment will be described. FIG. 7 is a perspective view of the gyro sensors 10 and 20 in one package. Each gyro sensor 10, 20 is provided in one package 90 shown in FIG. Such a package 90 is mounted on the printed circuit board 40 as shown in FIG.

  As described above, by providing the gyro sensors 10 and 20 in the package 90, the handling of the gyro sensors 10 and 20 can be facilitated.

(Sixth embodiment)
FIG. 8 is a schematic cross-sectional view of the sensor device 1 in the present embodiment. As shown in this figure, the first gyro sensor 10 is mounted on the first substrate 42, and the second gyro sensor 20 is mounted on the second substrate 43. And the 1st board | substrate 42 and the 2nd board | substrate 43 are arrange | positioned at the hollow part of case 71 which has a hollow part.

  Thus, each gyro sensor 10 and 20 can be mounted on a separate substrate. Moreover, even if it is such a structure, each gyro sensor 10 and 20 can be arrange | positioned on the same axis | shaft.

(Seventh embodiment)
FIG. 9 is a cross-sectional view of the laminated structure of the gyro sensors 10 and 20 in the present embodiment. As shown in this figure, a spacer 91 is disposed on the surface of the second gyro sensor 20 on which the second movable electrode 23 and the like are provided. Further, a surface of the first gyro sensor 10 opposite to the surface on which the first movable electrode 13 and the like are provided is disposed on the spacer 91. Thus, the first gyro sensor 10 serves as a cap for the second gyro sensor 20. A cap 92 is provided on the surface of the first gyro sensor 10 on which the first movable electrode 13 and the like are provided. Such a laminated structure is installed on the substrate 40.

  The spacer 91 may be annular or non-annular. As the material of the spacer 91, the vibration isolation member 80 shown in the second embodiment can be employed. In addition, as the cap 92, for example, one in which one surface of the semiconductor substrate is etched is used.

  As described above, by providing the spacers 91 and the caps 92 for the gyro sensors 10 and 20, the gyro sensors 10 and 20 can have a laminated structure.

(Eighth embodiment)
FIG. 10 is a cross-sectional view of a stacked structure of the gyro sensors 10 and 20 in the present embodiment. As shown in this figure, each of the gyro sensors 10 and 20 has a structure in which the sensing portion is covered with first and second caps 93 and 94, respectively. A laminated structure is formed in which the gyro sensors 10 and 20 sandwich the circuit chip 95 therebetween.

  Specifically, the surface of the first gyro sensor 10 on which the first movable electrode 13 or the like is provided is laminated with the first cap 93, and the surface of the second gyro sensor 20 on which the second movable electrode 23 or the like is provided. A second cap 94 is laminated on the substrate. A circuit chip 95 is disposed on the second cap 94, and the first gyro sensor 10 is disposed on the circuit chip 95. That is, a structure in which the circuit chip 95 is sandwiched between the second cap 94 and the first gyro sensor 10 is formed. The laminated structure is installed on the substrate 40.

  The circuit chip 95 is provided with a circuit for processing signals input from the gyro sensors 10 and 20. For example, the arithmetic circuit 30 may be provided in the circuit chip 95.

  As described above, each of the gyro sensors 10 and 20 is provided with the caps 93 and 94, and a laminated structure in which the circuit chip 95 is sandwiched may be employed.

(Other embodiments)
In the first embodiment, the sensor device 1 includes the arithmetic circuit 30 and the angular velocity component from which the acceleration is removed is output to the outside. However, the sensor device 1 may not include the arithmetic circuit 30. That is, the sensor device 1 may be configured such that only the outputs A and B of the gyro sensors 10 and 20 are output, and the acceleration is removed by the arithmetic circuit 30 provided outside the sensor device 1. What is necessary is just to perform a calculation.

  In each of the above embodiments, each gyro sensor 10, 20 is formed on a semiconductor substrate, but each gyro sensor 10, 20 may be formed on an SOI substrate. According to this, the semiconductor layer in which the sensing part is not formed can be bonded.

  In each of the above embodiments, the sensor device 1 using the two gyro sensors 10 and 20 has been described. However, three or more gyro sensors may be used for the sensor device 1. For example, the detection accuracy can be improved by arranging the detection vibration direction at a position that is a multiple of 90 °.

It is a block diagram of the 1st, 2nd gyro sensor used for the sensor apparatus which concerns on 1st Embodiment of this invention. It is a schematic diagram of arrangement | positioning of each gyro sensor. It is a whole schematic diagram of a sensor device. It is a schematic sectional drawing of the sensor apparatus in 2nd Embodiment of this invention. It is a schematic sectional drawing of the sensor apparatus in 3rd Embodiment of this invention. It is sectional drawing of the laminated structure of each gyro sensor in 4th Embodiment of this invention. It is a perspective view of the package in 5th Embodiment of this invention. It is a schematic sectional drawing of the sensor apparatus in 6th Embodiment of this invention. It is sectional drawing of the laminated structure of each gyro sensor in 7th Embodiment of this invention. It is sectional drawing of the laminated structure of each gyro sensor in 8th Embodiment of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 1st gyro sensor 13 detection movable electrode 14 detection fixed electrode 20 2nd gyro sensor 22 detection movable electrode 24 detection fixed electrode 30 arithmetic circuit 40 printed circuit board

Claims (1)

A first drive unit that vibrates in the direction of the x-axis with an axis extending in one direction as an x-axis, an axis perpendicular to the x-axis as a y-axis, and an axis perpendicular to the x-axis and the y-axis as a z-axis (15), a first detection weight (11) coupled to the first drive unit (15) so as to be displaced in the direction of the y-axis, and the y-axis provided to the first detection weight (11) A first movable electrode (13) that is displaced in a direction, and a first fixed electrode (14) disposed opposite to the first movable electrode (13), wherein the first movable electrode (13) includes the y-axis. A capacitance for detecting an angular velocity around the z-axis based on a change in capacitance between the first movable electrode (13) and the first fixed electrode (14) when a displacement of force due to Coriolis force occurs in the direction. A first gyro sensor (10) of the formula,
A second drive unit (25) that vibrates in the x-axis direction; a second detection weight (21) coupled to the second drive unit (25) so as to be displaced in the y-axis direction; 2 has a second movable electrode (23) that is provided on the detection weight (21) and is displaced in the y-axis direction, and a second fixed electrode (24) that is disposed to face the second movable electrode (23), When a displacement of force due to the Coriolis force occurs in the y-axis direction in the second movable electrode (23), a change in capacitance between the second movable electrode (23) and the second fixed electrode (24) occurs. A capacitive second gyro sensor (20) that detects an angular velocity about the z-axis based on the second gyro sensor (20),
The first gyro sensor (10) and the second gyro sensor (20) have the same structure, and the first gyro sensor (10) and the second gyro sensor (20) are identical on the z-axis. It is stacked as a detection axis,
A first cap (93) is stacked on a surface of the first gyro sensor (10) on which the first movable electrode (13) is provided, and the second movable electrode ( 23) is laminated on the surface provided with 23),
The second cap (94) and the first gyro sensor (10) have a laminated structure in which a circuit chip (95) is sandwiched,
When an angular velocity is applied to each of the first gyro sensor (10) and the second gyro sensor (20), the first movable electrode (13) of the first gyro sensor (10) and the second gyro sensor (20 The second movable electrode (23) is displaced in the opposite direction in the y-axis direction.

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