JP2018084480A - Physical quantity sensor, electronic apparatus, and mobile body - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a physical quantity sensor including an angular velocity/acceleration sensor with stable characteristics, an electronic apparatus, and a mobile body, without increasing the circuit size.SOLUTION: The physical quantity sensor includes: a vibration element having a first detection electrode and a second detection electrode; a first amplifier for amplifying a signal from the first detection electrode; a second amplifier for amplifying a signal from the second detection electrode; a converter for converting a first signal from the first amplifier into a first digital signal and converting a second signal from the second amplifier into a second digital signal; and a signal processing unit for calculating an angular velocity and an acceleration on the basis of the first and second digital signals.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a physical quantity sensor, an electronic device, and a moving object.

  2. Description of the Related Art A physical quantity detection device that detects a physical quantity such as angular velocity and acceleration using a vibrator such as a crystal vibrator (piezoelectric vibrator) or a MEMS (Micro Electro Mechanical Systems) vibrator is known.

  For example, as an angular velocity detection device for detecting the rotational angular velocity of a rotating system, a vibration gyro sensor using a piezoelectric element such as a quartz crystal vibrator is incorporated in various electronic devices, such as car navigation and camera shake detection during imaging. Has been used.

  For example, Patent Document 1, Patent Document 2, and Patent Document 3 have been proposed as techniques for detecting acceleration using an angular velocity sensor including such a vibration-type gyro sensor.

Japanese Patent Laid-Open No. 10-318755 JP 2012-112695 A JP 2012-042261 A

  However, in the physical quantity sensor described in Patent Document 1, an angular velocity detection electrode and an acceleration detection amount electrode are individually provided in the sensor element, and signals from each detection means are individually processed, which increases the circuit scale. Connected.

  In the physical quantity sensor described in Patent Document 2, the angular velocity component and the acceleration component output from one sensor element are separated, and the increase in circuit scale is small. Since the detection of acceleration is switched, it is easily affected by noise and it is difficult to obtain stable characteristics.

  Further, in the physical quantity sensor described in Patent Document 3, it is necessary to separately provide the angular velocity detection sensor element and the acceleration detection sensor element, leading to an increase in circuit scale.

  The present invention has been made in view of the above problems, and according to some aspects of the present invention, a physical quantity sensor capable of detecting angular velocity and acceleration with stable characteristics while suppressing an increase in circuit scale. An electronic device and a moving object can be provided.

  SUMMARY An advantage of some aspects of the invention is to solve at least a part of the problems described above, and the invention can be implemented as the following aspects or application examples.

[Application Example 1]
The physical quantity sensor according to this application example includes a vibration element including a first detection electrode and a second detection electrode, a first amplifier that amplifies a signal from the first detection electrode, and a signal from the second detection electrode. A second amplifier to amplify, a converter for converting a first signal from the first amplifier into a first digital signal, and a second signal from the second amplifier to a second digital signal; and the first digital A signal processing unit that calculates an angular velocity and an acceleration based on the signal and the second digital signal.

  According to the physical quantity sensor according to this application example, it is possible to detect two physical quantities, angular velocity and acceleration, using one vibration element.

  According to the physical quantity sensor according to this application example, the vibration element outputs detection signals of angular velocity and acceleration from a common pair of electrodes. Therefore, an amplifier that amplifies the angular velocity and acceleration detection signals can also be used in common with the angular velocity and acceleration, and an increase in circuit scale can be suppressed.

  Furthermore, according to the physical quantity sensor according to this application example, since the angular velocity and the acceleration are calculated based on the digital signal, it is possible to realize a physical quantity sensor that is not easily affected by noise or the like and has stable characteristics.

[Application Example 2]
In the physical quantity sensor according to the application example, the conversion unit performs time-division conversion of the first signal into the first digital signal and the conversion of the second signal into the second digital signal. Also good.

  According to the physical quantity sensor according to this application example, the conversion unit converts the first signal and the second signal detected by the vibration element into digital signals in a time-sharing manner, so that the first digital signal and the second digital signal are converted. The calculation process can be performed in a pseudo parallel manner. That is, a plurality of detection signals can be converted into digital signals by the same conversion unit, and an increase in circuit scale can be suppressed.

[Application Example 3]
In the physical quantity sensor according to the application example, the signal processing unit multiplies the first digital signal by a reference signal based on a drive signal that drives the vibration element, and the second digital signal, the reference signal, Multiplication processing for multiplying, a low-pass filter processing for the signal obtained by the multiplication processing, a first calculation processing for calculating an angular velocity by one of a sum operation and a difference operation of the signal obtained by the low-pass filter processing, You may perform the 2nd calculation process which calculates an acceleration by the other of the sum calculation and difference calculation of a 1st digital signal and a said 2nd digital signal.

  According to the physical quantity sensor according to this application example, in the signal processing unit, the angular velocity component including the frequency component of the driving signal is multiplied by the input digital signal and the reference signal, and the low-pass filter processing of the multiplied signal is executed. Then, the acceleration component that is calculated and does not include the frequency component of the drive signal is directly calculated from the input digital signal.

  That is, according to the physical quantity sensor according to this application example, the angular velocity and the acceleration can be calculated based on signals output from the same vibration element.

[Application Example 4]
In the physical quantity sensor according to the application example described above, the first signal and the second signal include at least one of an angular velocity component that is a component having a phase opposite to each other and an acceleration component that is a component having the same phase to each other. The difference calculation, and the second calculation process may be the sum calculation.

  According to the physical quantity sensor according to this application example, in addition to being able to detect the two physical quantities of angular velocity and acceleration simultaneously, the angular velocity is calculated by the difference calculation, so that the common-mode noise superimposed on the angular velocity component is reduced, It becomes possible to improve the detection accuracy of the angular velocity.

[Application Example 5]
In the physical quantity sensor according to the application example described above, the first signal and the second signal include at least one of an acceleration component that is a signal having a phase opposite to each other and an angular velocity component that is a signal having the same phase to each other. , The sum operation, and the second operation process may be the difference operation.

  According to the physical quantity sensor according to this application example, in addition to being able to detect the two physical quantities of angular velocity and acceleration at the same time, since the acceleration is calculated by the difference calculation, the common-mode noise superimposed on the acceleration component is reduced, It becomes possible to improve the detection accuracy of acceleration.

[Application Example 6]
In the physical quantity sensor according to the application example, the signal processing unit may include a calculation setting unit that sets a calculation rate of the sum calculation and a calculation rate of the difference calculation.

  According to the physical quantity sensor according to this application example, the signal processing unit can change the calculation rate of the sum calculation and the difference calculation for calculating the angular velocity and the acceleration.

  Thereby, according to the physical quantity sensor according to this application example, it is possible to set an optimal calculation rate according to the application, and there is a possibility that a physical versatile sensor with high versatility can be realized.

[Application Example 7]
In the physical quantity sensor according to the application example, the vibration element includes a base, a first detection arm that is connected to the base, the first detection electrode is formed, and is connected to the base, and the second detection electrode is A driving arm that vibrates and vibrates, the driving arm vibrates in the direction along the main surface of the vibration element, and an angular velocity around the first detection axis is applied. When the first detection arm and the second detection arm vibrate so as to vibrate in opposite directions, and acceleration in the second detection axis direction is applied, the first detection arm and the second detection arm The arms may vibrate so that they vibrate in the same direction.

  According to the physical quantity sensor according to this application example, when the angular velocity is applied around the first detection axis, the first detection arm and the second detection arm vibrate in the opposite directions to each other in the vibration element. When acceleration is applied in the direction, the first detection arm and the second detection arm vibrate in the same direction, so that two physical quantities of angular velocity and acceleration can be detected by one vibration element, and the circuit scale The increase can be suppressed.

[Application Example 8]
An electronic apparatus according to this application example includes any one of the physical quantity sensors described above.

  Since the electronic device according to this application example includes a physical quantity sensor that can detect angular velocity and acceleration with stable characteristics while suppressing an increase in circuit scale, a more reliable electronic device can be realized at lower cost. it can.

[Application Example 9]
The moving body according to this application example includes any one of the physical quantity sensors described above.

  Since the mobile body according to this application example includes a physical quantity sensor that can detect angular velocity and acceleration with stable characteristics while suppressing an increase in circuit scale, it is possible to realize a mobile body with higher reliability at a lower cost. it can.

It is a functional block diagram of the physical quantity sensor concerning a 1st embodiment. It is a top view which shows a double T type vibration element typically. It is a top view which shows a double T type vibration element typically. It is a figure which shows the output signal of a double T type vibration element. It is a top view which shows a double T type vibration element typically. It is a figure which shows the output signal of a double T type vibration element. It is a top view which shows typically an H-type vibration element. It is a side view which shows typically an H type vibration element. It is a side view which shows typically an H type vibration element. It is a figure which shows the output signal of an H-type vibration element. It is a side view which shows typically an H type vibration element. It is a figure which shows the output signal of an H-type vibration element. It is a perspective view of the physical quantity sensor in 2nd Embodiment. It is the figure which showed the relationship between the some physical element in 2nd Embodiment, and the physical quantity which can be detected. It is a functional block diagram of a physical quantity sensor detection circuit according to a second embodiment. It is a functional block diagram of a physical quantity sensor detection circuit according to a second embodiment. It is a top view which shows typically the H type vibration element in 3rd Embodiment. It is sectional drawing of a vibration element in 3rd Embodiment. It is sectional drawing of a vibration element in 3rd Embodiment. It is sectional drawing of a vibration element in 3rd Embodiment. It is the figure which showed the relationship between the some vibration element in 3rd Embodiment, and the physical quantity which can be detected. It is a perspective view of the physical quantity sensor in a 4th embodiment. It is the figure which showed the relationship between the some vibration element in 4th Embodiment, and the physical quantity which can be detected. It is a perspective view which shows typically the electronic device which concerns on this embodiment. It is a perspective view which shows typically the electronic device which concerns on this embodiment. It is a perspective view which shows typically the electronic device which concerns on this embodiment. It is a perspective view which shows typically the mobile body which concerns on this embodiment.

  DESCRIPTION OF EMBODIMENTS Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the drawings. The embodiments described below do not unduly limit the contents of the present invention described in the claims. Also, not all of the configurations described below are essential constituent requirements of the present invention.

  Hereinafter, a physical quantity sensor that detects angular velocity and acceleration as a physical quantity will be described as an example, but a physical quantity sensor that detects a physical quantity other than angular velocity and acceleration is also included in the present invention.

1. Physical Quantity Sensor 1.1 First Embodiment FIG. 1 is a functional block diagram of a physical quantity sensor according to a first embodiment. As shown in FIG. 1, the physical quantity sensor 1 according to the present embodiment includes an IC (Integrated Circuit) 2 and a vibration element 100, and further performs various calculation processes and controls using output data of the physical quantity sensor 1. An MCU (Micro Control Unit) 50 that performs processing may be included.

  The vibration element 100 includes a vibration piece in which a drive electrode and a detection electrode are arranged. In general, the vibration element 100 is airtight so as to reduce the impedance of the vibration piece as much as possible and increase the oscillation efficiency. Sealed in a package.

  Note that the resonator element of the vibration element 100 may be a piezoelectric material such as quartz, lithium tantalate, or lithium niobate, or may be a piezoelectric material such as piezoelectric ceramics such as lead zirconate titanate.

  The vibration element 100 according to this embodiment is a so-called double T-type vibration element 100-1 having two T-type drive vibration arms as shown in FIGS. 2, 3A, and 4A.

  2, 3A, and 4A are plan views (views of the main surface 180) schematically showing the resonator element 100-1 of the present embodiment. 2, 3A, and 4A, three axes orthogonal to each other are illustrated, and the x axis, the y axis, and the z axis are illustrated.

  The vibration element 100-1 includes a base 130, connecting arms 131 and 132, drive vibration arms (an example of “drive arm”) 113, 114, 115, and 116, a drive input electrode 111, a drive output electrode 112, Detection vibration arm (an example of “first detection arm”) 123, detection vibration arm (an example of “second detection arm”) 124, first detection electrode 121, second detection electrode 122, and common electrode 125 ,including.

  The base 130 has a planar shape, for example, a rectangle (substantially rectangular).

  The connecting arm 131 and the connecting arm 132 extend from the base 130 in opposite directions along the x axis. As shown in FIG. 2, the connecting arm 131 extends from the base portion 130 in the −x-axis direction, and the connecting arm 132 extends from the base portion 130 in the + x-axis direction.

  The drive vibrating arm 113 and the drive vibrating arm 114 extend in the opposite directions along the y-axis direction from the connecting arm 131. As shown in FIG. 2, the drive vibration arm 113 extends from the connection arm 131 in the + y axis direction, and the drive vibration arm 114 extends from the connection arm 131 in the −y axis direction. The drive vibrating arm 113 and the drive vibrating arm 114 are connected to the base portion 130 via the connecting arm 131.

  The drive vibrating arm 115 and the drive vibrating arm 116 extend from the connecting arm 132 in opposite directions along the Y-axis direction. As shown in FIG. 2, the driving vibrating arm 115 extends from the connecting arm 132 in the + y-axis direction, and the driving vibrating arm 116 extends from the connecting arm 132 in the −y-axis direction. The drive vibrating arm 115 and the drive vibrating arm 116 are connected to the base portion 130 via the connecting arm 132.

  The drive input electrode 111 is formed on the main surface 180 of the vibration element 100-1 of the drive vibration arm 113 and the drive vibration arm 114, and the drive output electrode 112 is formed on the side surface of the drive vibration arm 113 and the drive vibration arm 114, respectively. Has been.

  The drive output electrode 112 is formed on the main surface 180 of the vibration element 100-1 of the drive vibration arm 115 and the drive vibration arm 116, and the drive input electrode 111 is formed on the side surface of the drive vibration arm 115 and the drive vibration arm 116, respectively. Has been.

  The detection vibrating arm 123 and the detection vibrating arm 124 extend from the base 130 in opposite directions along the y axis. As shown in FIG. 2, the detection vibrating arm 123 extends from the base portion 130 in the + y-axis direction, and the detection vibrating arm 124 extends from the base portion 130 in the −y-axis direction.

  A first detection electrode 121 is formed on the main surface 180 of the vibration element 100-1 of the detection vibration arm 123, and a common electrode 125 is formed on the side surface of the detection vibration arm 123 on the drive vibration arm 113 side. The second detection electrode 122 is formed on the main surface 180 of the vibration element 100-1 of the detection vibration arm 124, and the common electrode 125 is formed on the side surface of the detection vibration arm 124 on the drive vibration arm 114 side. The common electrode 125 is grounded.

  When an alternating voltage as a drive signal DRV is applied between the drive input electrode 111 and the drive output electrode 112, the drive vibrating arms 113, 114, 115, and 116 of the vibration element 100-1 are indicated by the arrow A due to the inverse piezoelectric effect. Thus, the drive vibration is generated in the direction along the main surface 180 of the vibration element 100-1.

  Specifically, when an AC voltage as a drive signal DRV is applied between the drive input electrode 111 and the drive output electrode 112, the tip of the drive vibration arm 113 and the tip of the drive vibration arm 115 repeatedly approach and separate from each other. A bending motion (excitation vibration) is performed, and the distal end of the driving vibration arm 114 and the distal end of the driving vibration arm 116 repeatedly bend and move toward and away from each other. When the tip of the drive vibration arm 113 and the tip of the drive vibration arm 115 are close to each other, the tip of the drive vibration arm 114 and the tip of the drive vibration arm 116 are close to each other, and the tip of the drive vibration arm 113 and the drive vibration When the tips of the arms 115 are separated from each other, the tips of the drive vibrating arms 114 and the tips of the drive vibrating arms 116 operate so as to be separated from each other.

  In this state, when an angular velocity 150 with the z-axis direction as the first detection axis 160 is applied to the vibration element 100-1, the drive vibration arms 113, 114, 115, and 116 are indicated by the arrow A as shown in FIG. 3A. Coriolis force is obtained in a direction (y-axis direction) perpendicular to both the direction of bending vibration (x-axis direction) and the first detection axis 160 (z-axis direction) with an angular velocity of 150. As a result, as shown in FIG. 3A, the connecting arms 131 and 132 vibrate in the y-axis direction as indicated by an arrow B, and the detected vibrating arms 123 and 124 are moved to an arrow C as the connecting arms 131 and 132 vibrate. As shown, it bends and vibrates in the x-axis direction.

  Then, AC charges based on these bending vibrations are generated in the first detection electrode 121 and the second detection electrode 122 by the piezoelectric effect. Here, the AC charge generated based on the Coriolis force changes according to the magnitude of the Coriolis force (in other words, the magnitude of the angular velocity 150).

  At this time, the connecting arms 131 and 132 vibrate so as to be in opposite phases to each other, and similarly, the detection vibrating arms 123 and 124 bend and vibrate so as to be in opposite phases. That is, when the piezoelectric material of the vibration element 100-1 existing between the common electrode 125 provided on the side surface of the detection vibration arm 123 on the drive vibration arm 113 side and the first detection electrode 121 expands, the detection vibration arm 124. The piezoelectric material of the vibration element 100-1 existing between the common electrode 125 and the second detection electrode 122 provided on the side surface of the drive vibration arm 114 is compressed, and the drive vibration arm 113 side of the detection vibration arm 123 is compressed. When the piezoelectric material of the vibration element 100-1 existing between the common electrode 125 and the first detection electrode 121 provided on the side surface is compressed, the detection vibration arm 124 is provided on the side surface on the drive vibration arm 114 side. The piezoelectric material of the vibration element 100-1 existing between the common electrode 125 and the second detection electrode 122 expands. As a result, the AC charges generated in the first detection electrode 121 and the second detection electrode 122 due to the piezoelectric effect are in reverse phase as shown in FIG. 3B.

  When the acceleration 151 is applied to the vibration element 100-1 in the direction of the second detection axis 170 substantially parallel to the x axis, the detection vibrating arms 123 and 124 are caused by the force generated by the acceleration 151, as shown in FIG. 4A. As shown by the arrow D, bending vibration (forced vibration) is performed in the x-axis direction.

  Then, AC charges based on these bending vibrations are generated in the first detection electrode 121 and the second detection electrode 122 by the piezoelectric effect. Here, the AC charge generated based on the acceleration 151 changes in accordance with the force applied to the vibration element 100-1 by the acceleration 151. In addition, as a factor that the acceleration 151 is applied to the vibration element 100-1, for example, when an impact is applied to the casing on which the physical quantity sensor 1 is mounted.

  At this time, the detection vibrating arms 123 and 124 perform in-phase bending vibrations. That is, when the piezoelectric material of the vibration element 100-1 existing between the common electrode 125 provided on the side surface of the detection vibration arm 123 on the drive vibration arm 113 side and the first detection electrode 121 expands, the detection vibration arm 124. The piezoelectric material of the vibration element 100-1 existing between the common electrode 125 and the second detection electrode 122 provided on the side surface of the drive vibration arm 114 is expanded, and the drive vibration arm 113 side of the detection vibration arm 123 is expanded. When the piezoelectric material of the vibration element 100-1 existing between the common electrode 125 and the first detection electrode 121 provided on the side surface is compressed, the detection vibration arm 124 is provided on the side surface on the drive vibration arm 114 side. The piezoelectric material of the vibration element 100-1 existing between the common electrode 125 and the second detection electrode 122 is compressed. As a result, the AC charges generated in the first detection electrode 121 and the second detection electrode 122 due to the piezoelectric effect are in phase as shown in FIG. 4B.

  The vibration element 100 according to the present embodiment may be a vibration element 100-2 having a planar shape of H as shown in FIG. 5A.

  FIG. 5A is a plan view schematically showing the vibration element 100-2 of the present embodiment (views of the main surface 180), and FIGS. 5B, 6A, and 7A are H-shaped vibrations of the present embodiment. 3 is a side view schematically showing the element 100-2 (a view of a side surface 190). FIG. 5A, FIG. 5B, FIG. 6A, and FIG. 7A show three axes that are orthogonal to each other, and the x axis, the y axis, and the z axis are illustrated.

  As shown in FIG. 5A, the vibration element 100-2 includes a base 130, a drive vibration arm (an example of a “drive arm”) 113 and 115, a drive input electrode 111, a drive output electrode 112, and a detection vibration arm ( An example of “first detection arm” 123, a detection vibration arm (example of “second detection arm”) 124, a first detection electrode 121, and a second detection electrode 122 are included.

  The base 130 has a planar shape, for example, a rectangle (substantially rectangular).

  The drive vibrating arm 113 extends in the −y axis direction from the base portion 130 along the y axis direction.

  The drive vibration arm 114 extends in the −y axis direction from the base portion 130 along the y axis direction in parallel with the drive vibration arm 113.

  The detection vibrating arms 123 extend in the + y-axis direction from the base portion 130 in the direction opposite to the driving vibrating arms 113 along the y-axis direction.

  The detection vibration arm 124 extends in the + y-axis direction from the base 130 in the direction opposite to the drive vibration arm 115 along the y-axis direction and in parallel with 124 by the detection vibration.

  The drive input electrode 111 is formed on the main surface 180 of the vibration element 100-2 of the drive vibration arm 113, and the drive output electrode 112 is formed on the side surface 190 of the vibration element 100-2 of the drive vibration arm 113.

  The drive output electrode 112 is formed on the main surface 180 of the vibration element 100-2 of the drive vibration arm 115, and the drive input electrode 111 is formed on the side surface 190 of the vibration element 100-2 of the drive vibration arm 115. .

  A first detection electrode 121 is formed on the main surface 180 of the vibration element 100-2 of the detection vibration arm 123, and a common electrode 125 is formed on the side surface 190 of the vibration element 100-2 of the detection vibration arm 123.

  The second detection electrode 122 is formed on the main surface 180 of the vibration element 100-2 of the detection vibration arm 124, and the common electrode 125 is formed on the side surface 190 of the vibration element 100-2 of the detection vibration arm 123. . The common electrode 125 is grounded.

  When an AC voltage as a drive signal DRV is applied between the drive input electrode 111 and the drive output electrode 112, the drive vibration arms 113 and 115 of the vibration element 100-2 vibrate as indicated by an arrow E due to the inverse piezoelectric effect. Drive and vibrate in a direction along the main surface 180 of the element 100-2.

  Specifically, when an AC voltage as a drive signal DRV is applied between the drive input electrode 111 and the drive output electrode 112, the distal ends of the drive vibration arm 113 and the drive vibration arm 115 repeatedly move toward and away from each other and bend. (Excitation vibration). At this time, as shown in FIG. 5B, the vibration element 100-2 does not change in the z-axis direction.

  In this state, when an angular velocity 150 with the y-axis direction as the first detection axis 160 is applied to the vibration element 100-2, as shown in FIG. 6A, the drive vibration arms 113 and 115 are connected to the arrow E shown in FIG. Coriolis force is obtained in a direction (z-axis direction) perpendicular to both the direction of bending vibration (x-axis direction) and the first detection axis 160 (y-axis direction) of the angular velocity 150 shown in FIG. 6A. As a result, as shown in FIG. 6A, the drive vibration arms 113 and 115 and the detection vibration arms 123 and 124 bend and vibrate in the z-axis direction as indicated by an arrow F.

  Then, like the double T-type vibrating element 100-1, AC charges based on these bending vibrations are generated in the first detection electrode 121 and the second detection electrode 122 by the piezoelectric effect. Here, the AC charge generated based on the Coriolis force changes according to the magnitude of the Coriolis force (in other words, the magnitude of the angular velocity 150).

  At this time, the detection vibrating arms 123 and 124 bend and vibrate so as to be in opposite phases to each other. That is, the vibration element 100-existing between the first detection electrode 121 provided on the main surface 180 of the vibration element 100-2 of the detection vibration arm 123 and the common electrode 125 provided on the side surface 190 of the detection vibration arm 123. Between the second detection electrode 122 provided on the main surface 180 of the vibration element 100-2 of the detection vibrating arm 124 and the common electrode 125 provided on the side surface 190 of the detection vibrating arm 124 when the second piezoelectric material is expanded. The piezoelectric material of the vibration element 100-2 existing in FIG. 5 is compressed and provided on the first detection electrode 121 provided on the main surface 180 of the vibration element 100-2 of the detection vibration arm 123 and the side surface 190 of the detection vibration arm 123. When the piezoelectric material of the vibration element 100-2 existing between the common electrode 125 is compressed, the second detection electrode 122 provided on the main surface 180 of the vibration element 100-2 of the detection vibration arm 124 is detected. The piezoelectric material of the vibrating element 100-2 which exists between the common electrode 125 provided on the side surface 190 of the vibrating arm 124 extends. As a result, the AC charges generated in the first detection electrode 121 and the second detection electrode 122 due to the piezoelectric effect are in reverse phase as shown in FIG. 6B.

  Further, when the acceleration 151 is applied to the vibration element 100-2 in the direction of the second detection axis 170 substantially parallel to the z-axis, the detection vibrating arms 123 and 124 are caused by the force generated by the acceleration 151 as shown in FIG. As shown by an arrow G, bending vibration (forced vibration) occurs in the z-axis direction.

  Then, AC charges based on these bending vibrations are generated in the first detection electrode 121 and the second detection electrode 122 by the piezoelectric effect. Here, the AC charge generated based on the acceleration 151 changes in accordance with the force applied to the vibration element 100-2 by the acceleration 151. In addition, as a factor that the acceleration 151 is applied to the vibration element 100-2, for example, when an impact is applied to the casing in which the physical quantity sensor 1 is mounted.

  At this time, the detection vibrating arms 123 and 124 perform bending vibrations in the same phase. That is, the vibration element 100-existing between the first detection electrode 121 provided on the main surface 180 of the vibration element 100-2 of the detection vibration arm 123 and the common electrode 125 provided on the side surface 190 of the detection vibration arm 123. Between the second detection electrode 122 provided on the main surface 180 of the vibration element 100-2 of the detection vibrating arm 124 and the common electrode 125 provided on the side surface 190 of the detection vibrating arm 124 when the second piezoelectric material is expanded. The piezoelectric material of the vibration element 100-2 existing in FIG. 3 expands and is provided on the first detection electrode 121 provided on the main surface 180 of the vibration element 100-2 of the detection vibration arm 123 and the side surface 190 of the detection vibration arm 123. When the piezoelectric material of the vibration element 100-2 existing between the common electrode 125 is compressed, the second detection electrode 122 provided on the main surface 180 of the vibration element 100-2 of the detection vibration arm 124 is detected. The piezoelectric material of the vibrating element 100-2 which exists between the common electrode 125 provided on the side surface 190 of the vibrating arm 124 compresses. As a result, the AC charges generated in the first detection electrode 121 and the second detection electrode 122 due to the piezoelectric effect are in phase as shown in FIG. 7B.

  In this embodiment, the double T-type vibration element 100-1 and the H-type vibration element 100-2 will be described as the vibration element 100 when it is not necessary to distinguish between them.

  Returning to FIG. 1, the IC 2 in the present embodiment detects a detected vibration of the vibration element 100 when a driving circuit 10 for driving and vibrating the vibration element 100 and an angular velocity or acceleration (an example of a physical quantity) are applied. And a detection circuit 20.

  The drive circuit 10 includes an amplitude adjustment circuit 11, an I / V conversion circuit (current / voltage conversion circuit) 12, and an AC amplification circuit 13. The drive circuit 10 drives the drive input electrode 111 of the vibration element 100 to drive the drive vibration arms 113, 114, 115, and 116 (see FIG. 2; in the H-type vibration element 100-2, the drive vibration arms 113 and 115). In this circuit, a signal DRV is output and a signal output from the drive output electrode 112 of the vibration element 100 is input.

  When the drive vibration arms 113, 114, 115, 116 of the vibration element 100 vibrate, an alternating current based on the piezoelectric effect is output from the drive output electrode 112 and input to the I / V conversion circuit 12. The I / V conversion circuit 12 converts the input AC current into an AC voltage signal having the same frequency as the vibration frequency of the drive vibrating arms 113, 114, 115, 116 and outputs the AC voltage signal.

  The AC voltage signal output from the I / V conversion circuit 12 is input to the AC amplifier circuit 13. The AC amplifier circuit 13 amplifies and outputs the input AC voltage signal.

  The AC voltage signal output from the AC amplifier circuit 13 is input to the amplitude adjustment circuit 11. The amplitude adjustment circuit 11 controls the gain so as to keep the amplitude of the input AC voltage signal constant, and outputs the AC voltage signal after gain control to the drive input electrode 111 of the vibration element 100. The drive vibrating arms 113, 114, 115, 116 are driven to vibrate by the AC voltage signal (drive signal DRV) input to the drive input electrode 111.

  The detection circuit 20 includes a charge amplifier (an example of “first amplifier”) 21, a charge amplifier (an example of “second amplifier”) 22, a conversion unit 23, a signal processing unit 24, an interface circuit 25, an A / A D conversion circuit 26.

  The charge amplifier 21 is electrically connected to the first detection electrode 121 of the vibration element 100, and converts a current signal based on the AC charge output from the first detection electrode 121 into a first signal Sig1 that is an AC voltage. The charge amplifier 22 is electrically connected to the second detection electrode 122 of the vibration element 100, and converts a current signal based on the AC charge output from the second detection electrode 122 into a second signal Sig2 that is an AC voltage.

  Specifically, each of the charge amplifier 21 and the charge amplifier 22 includes, for example, an operational amplifier, a feedback resistor, and a feedback capacitor. An AC current based on the AC charge output from the first detection electrode 121 or the second detection electrode 122 is input to the inverting input terminal (− terminal) of the operational amplifier, and a reference is supplied to the non-inverting amplification terminal (+ terminal). A voltage is input. By passing through this operational amplifier, the charge amplifier 21 amplifies the AC charge, which is a signal input from the first detection electrode 121, and converts it into the first signal Sig1, and the charge amplifier 22 receives from the second detection electrode 122. The AC charge that is an input signal is amplified and converted into a second signal Sig2.

  The conversion unit 23 includes switches 35 and 36, an A / D conversion circuit 31, and registers 32 and 33.

  The conversion unit 23 converts the first signal Sig1 from the charge amplifier 21 into the first digital signal Dig1 in a time division manner, and converts the second signal Sig2 from the charge amplifier 22 into the second digital signal Dig2.

  Specifically, the first signal Sig1 and the second signal Sig2 input to the conversion unit 23 are sequentially input to the A / D conversion circuit 31 by the switches 35 and 36. The switches 35 and 36 are sequentially turned on by a switch control signal Ctr output from a control unit (not shown). That is, the switch 35 is turned on and the switch 36 is turned off at a certain time t, and the first signal Sig1 is input to the A / D conversion circuit 31, and the switch 35 is turned off and the switch 36 is turned on at time t + 1. Thus, the second signal Sig2 is input to the A / D conversion circuit 31.

  The A / D conversion circuit 31 converts the first signal Sig1 and the second signal Sig2 input in time division into digital signals. At this time, the digital signal converted by the A / D conversion circuit 31 is sequentially held in the register 32 or the register 33 in conjunction with the switch control signal Ctr. As a result, the first signal Sig1 and the second signal Sig2 A / D converted in a time division manner are converted into digital signals and sequentially held in the register 32 or the register 33 in conjunction with the switch control signal Ctr. For example, the digital signal obtained by A / D converting the first signal Sig1 is held in the register 32 at a certain time t, and the digital signal obtained by A / D converting the second signal Sig2 is held in the register 33 at the time t + 1. The That is, the digital signal held in the register 32 is the first digital signal Dig1, and the digital signal held in the register 33 is the second digital signal Dig2.

  Thus, the conversion unit 23 performs A / D conversion of the first signal Sig1 and the second signal Sig2 in a time-sharing manner, thereby performing a calculation process for the first digital signal Dig1 and a calculation process for the second digital signal Dig2. In parallel.

  The A / D conversion circuit 26 AD-converts a signal based on the drive signal DRV that drives the vibration element 100 and outputs a reference signal SDET. Specifically, the A / D conversion circuit 26 receives the voltage signal output from the AC amplifier circuit 13 of the drive circuit 10, converts the voltage signal into a reference signal SDET that is a digital signal, and outputs the reference signal SDET to the signal processing unit 24.

  The signal processing unit 24 includes a multiplication processing unit 41, a low-pass filter processing unit 42 (LPF: Low Pass Filter), a first arithmetic processing unit 43, and a second arithmetic processing unit 44.

  The signal processing unit 24 calculates an angular velocity and an acceleration based on the first digital signal Dig1 and the second digital signal Dig2.

  Specifically, in the present embodiment, the signal processing unit 24 multiplies the first digital signal Dig1 by the reference signal SDET based on the drive signal DRV that drives the vibration element 100, and the second digital signal Dig2 and the reference signal A multiplication process for multiplying the SDET, a low-pass filter process for the signal obtained by the multiplication process, and a first computation process for calculating the angular velocity of the signal obtained by the low-pass filter process by one of a sum operation and a difference operation. . In the present embodiment, the signal processing unit 24 performs a second calculation process for calculating acceleration by the other of the sum calculation and the difference calculation of the first digital signal Dig1 and the second digital signal Dig2.

  Further, as described above, in the present embodiment, the AC charge output from the first detection electrode 121 and the AC charge output from the second detection electrode 122 of the vibration element 100 have an angular velocity component that is a component opposite to each other and an in-phase component. Including at least one of the acceleration components. Therefore, the first signal Sig1 based on the output signal of the first detection electrode 121 and the second signal Sig2 based on the output signal of the second detection electrode 122 are also an angular velocity component which is a component in opposite phase and an acceleration which is a component in phase with each other. Including at least one of the components. Here, when the first signal Sig1 and the second signal Sig2 include angular velocity components having opposite phases, the angular velocity component is extracted by calculating a difference between the first signal Sig1 and the second signal Sig2. Can do. Further, when the first signal Sig1 and the second signal Sig2 include in-phase acceleration components, the acceleration component can be extracted by calculating the sum of the first signal Sig1 and the second signal Sig2. . That is, in the present embodiment, the first calculation process for calculating the angular velocity is a difference calculation, and the second calculation process for calculating the acceleration is a sum calculation.

  Specifically, the first digital signal Dig1 and the second digital signal Dig2 output from the conversion unit 23 are input to a multiplication processing unit 41 that performs multiplication processing on each of them. The first digital signal Dig1 and the second digital signal Dig2 are each multiplied by the reference signal SDET in the multiplication processing unit 41. Further, each multiplied digital signal is input to a low-pass filter processing unit 42 that performs a low-pass filter process, and a high-frequency component is removed (more precisely, the high-frequency component is attenuated to a predetermined level or less). That is, the multiplication processing unit 41 and the low-pass filter processing unit 42 have a function as a synchronous detection circuit. Thereafter, the first arithmetic processing unit 43 calculates the difference between the signals output from the low-pass filter processing unit 42 (difference calculation), thereby generating the angular velocity signal VD1. Further, the second arithmetic processing unit 44 generates the acceleration signal VD2 by calculating (summing) the sum of the first digital signal Dig1 and the second digital signal Dig2.

  As described above, in the present embodiment, the signal processing unit 24 calculates the angular velocity and acceleration by digital processing, so that it is difficult to be affected by noise and the like, and the angular velocity and acceleration can be calculated.

The interface circuit 25 outputs the angular velocity signal VD1 and the acceleration signal VD2 output from the signal processing unit 24 to the MCU 50 through, for example, an SPI (Serial Peripheral Interface) bus. The interface circuit 25 receives various commands transmitted by the MCU 50 and performs processing for transmitting data corresponding to the commands to the MCU 50. Further, in response to a request from the MCU 50, the interface circuit 25 reads out data stored in a storage unit (not shown) (nonvolatile memory, register, etc.) and outputs the data to the MCU 50, or stores data output from the MCU 50. The process of writing to the copy is performed. The interface circuit 25 may be an interface circuit 25 corresponding to various buses other than the SPI bus, such as an I ² C (Inter-Integrated Circuit) bus.

  According to the physical quantity sensor 1 according to the first embodiment, when the angular velocity 150 is applied around the first detection axis 160, the vibration element 100 causes the detection vibration arm 123 and the detection vibration arm 124 to vibrate in opposite directions. When the acceleration 151 is applied in the direction of the second detection axis 170, the detection vibration arm 123 and the detection vibration arm 124 vibrate in the same direction. Thereby, the physical quantity sensor 1 according to the first embodiment can detect two physical quantities, angular velocity and acceleration, by using one vibration element 100.

  Further, the vibration element 100 outputs detection signals of angular velocity and acceleration from the first detection electrode 121 and the second detection electrode 122 which are a common pair of electrodes. Therefore, the charge amplifiers 21 and 22 for amplifying the angular velocity and acceleration detection signals can be used in common for both the angular velocity component and the acceleration component. Further, the first signal Sig1 and the second signal Sig2 output from the charge amplifiers 21 and 22 are input to the conversion unit 23 in a time division manner, so that the single conversion unit 23 can convert the digital signal. Thereby, the physical quantity sensor 1 according to the first embodiment can suppress an increase in circuit scale.

  Further, according to the physical quantity sensor 1 according to the first embodiment, the signal processing unit 24 performs calculation of angular velocity and acceleration based on the first digital signal Dig1 and the second digital signal Dig2. For this reason, the physical quantity sensor 1 which is hardly affected by noise or the like and has stable characteristics can be realized.

1.2 Second Embodiment In the physical quantity sensor 1 in the first embodiment, the uniaxial angular velocity and the uniaxial acceleration are calculated, but the physical quantity sensor 1 in the second embodiment uses three vibration elements 100. Thus, the triaxial angular velocity and the biaxial acceleration are calculated. In addition, about the physical quantity sensor 1 of 2nd Embodiment, the same code | symbol is attached | subjected to the component similar to 1st Embodiment, a different point from 1st Embodiment is demonstrated, and the description which overlaps with 1st Embodiment is given. Omitted.

  FIG. 8 is a perspective view of the physical quantity sensor 1 in the second embodiment. In the figure shown in FIG. 8, the X axis, the Y axis, and the Z axis are shown as three axes orthogonal to each other.

  The physical quantity sensor 1 according to the second embodiment includes a box-shaped base 300 having one surface opened, a plate-shaped lid (not shown) that closes the opening surface of the base 300, a first vibration element 100a, and a second vibration element. 100b, the 3rd vibration element 100c, and IC2 not shown are comprised. The physical quantity sensor 1 includes a first vibration element 100a, a second vibration element 100b, a third vibration element 100c, and a package (not shown) that are hermetically sealed with a box-shaped base 300 and a lid. IC2 is arranged.

  Since the structure and operation of each of the plurality of vibration elements 100 in the second embodiment are the same as those in the first embodiment (FIGS. 2 to 7B), illustration and description thereof are omitted.

  Although not shown, the physical quantity sensor 1 according to the second embodiment includes a drive circuit 10, a conversion unit 23, a signal processing unit 24, an interface circuit 25, and an A / D conversion circuit, as in the first embodiment (FIG. 1). 26. Further, the physical quantity sensor 1 includes three sets of charge amplifiers 21a, 22a, 21b, 22b, 21c, and 22c.

  The first vibration element 100a is an H-type vibration element 100-2 shown in FIGS. 5A to 7B. In the first vibrating element 100a, the first detection shaft 160 shown in FIG. 6A and the second detection shaft 170 shown in FIG. 7A are arranged along the X axis and the Z axis in FIG. 8, respectively. That is, the first vibration element 100a can detect the angular velocity around the first detection axis 160 along the X axis and the acceleration in the direction of the second detection axis 170 along the Z axis in FIG.

  The second vibration element 100b is an H-type vibration element 100-2 shown in FIGS. 5A to 7B. In the second vibration element 100b, the first detection shaft 160 shown in FIG. 6A and the second detection shaft 170 shown in FIG. 7A are arranged along the Y axis and the Z axis in FIG. 8, respectively. That is, the second vibration element 100b can detect the angular velocity around the first detection axis 160 along the Y axis and the acceleration in the direction of the second detection axis 170 along the Z axis in FIG.

  The third vibrating element 100c is a double T-shaped vibrating element 100-1 shown in FIGS. In the third vibrating element 100c, the first detection shaft 160 shown in FIG. 3A and the second detection shaft 170 shown in FIG. 4A are arranged along the Z axis and the X axis in FIG. 8, respectively. That is, the third vibration element 100c can detect the angular velocity around the first detection axis 160 along the Z axis and the acceleration in the direction of the second detection axis 170 along the X axis in FIG.

  FIG. 9 is a diagram illustrating a relationship between a plurality of vibration elements 100 and physical quantities that can be detected in the physical quantity sensor 1 of the second embodiment. As shown in FIG. 9, the physical quantity sensor 1 in the second embodiment determines the X-axis angular velocity based on the first detection electrode 121 a (see FIG. 10) and the second detection electrode 122 a (see FIG. 10) of the first vibration element 100 a. , And the Y-axis angular velocity is detected by a reverse-phase signal between the first detection electrode 121b (see FIG. 10) and the second detection electrode 122b (see FIG. 10) of the second vibration element 100b. The Z-axis angular velocity can be detected by signals in reverse phase from the first detection electrode 121c (see FIG. 10) and the second detection electrode 122c (see FIG. 10) of the third vibration element 100c. Furthermore, the physical quantity sensor 1 according to the second embodiment uses the in-phase signal of the X-axis acceleration from the first detection electrode 121c (see FIG. 10) and the second detection electrode 122c (see FIG. 10) of the third vibration element 100c. The Z-axis acceleration is detected and the in-phase signal of the first detection electrode 121a (see FIG. 10) and the second detection electrode 122a (see FIG. 10) of the first vibration element 100a and the first detection of the second vibration element 100b. Detection can be performed by a signal in phase between the electrode 121b (see FIG. 10) and the second detection electrode 122b (see FIG. 10). In the physical quantity sensor 1 in the second embodiment, the Z-axis acceleration is detected by the first vibration element 100a and the second vibration element 100b. Therefore, for the Z-axis acceleration, either detection result of the first vibration element 100a or the second vibration element 100b may be used, or the Z-axis acceleration may be calculated by averaging both detection results.

  Thus, the physical quantity sensor 1 according to the second embodiment is capable of detecting X-axis, Y-axis, and Z-axis angular velocities (3-axis angular velocities) and X-axis and Z-axis accelerations (2-axis acceleration). It is a sensor.

  FIG. 10 is a block diagram showing the charge amplifiers 21a, 21b, 21c, 22a, 22b, 22c and the conversion unit 23 included in the detection circuit 20 in the second embodiment.

  The charge amplifier 21a performs current / voltage conversion and amplification on the AC charge output from the first detection electrode 121a of the first vibration element 100a, and outputs a first signal Sig1a. In addition, the charge amplifier 22a performs current / voltage conversion and amplification on the AC charge output from the second detection electrode 122a of the first vibration element 100a, and outputs a second signal Sig2a.

  The charge amplifier 21b performs current / voltage conversion and amplification on the AC charge output from the first detection electrode 121b of the second vibration element 100b, and outputs a first signal Sig1b. In addition, the charge amplifier 22b performs current / voltage conversion and amplification on the AC charge output from the second detection electrode 122b of the second vibration element 100b, and outputs a second signal Sig2b.

  The charge amplifier 21c performs current / voltage conversion and amplification on the AC charge output from the first detection electrode 121c of the third vibration element 100c, and outputs a first signal Sig1c. In addition, the charge amplifier 22c performs current / voltage conversion and amplification on the AC charge output from the second detection electrode 122c of the third vibrating element 100c, and outputs a second signal Sig2c.

  The charge amplifiers 21a, 21b, and 21c have the same configuration as the charge amplifier 21 of the first embodiment, and a detailed description thereof is omitted. Similarly, the charge amplifiers 22a, 22b, and 22c have the same configuration as the charge amplifier 22 of the first embodiment, and detailed description thereof is omitted.

  The converter 23 receives the first signals Sig1a, Sig1b, Sig1c and the second signals Sig2a, Sig2b, Sig2c, performs A / D conversion in a time division manner, and converts the signals into digital signals. Specifically, the first signal Sig1a, Sig1b, Sig1c and the second signal Sig2a, Sig2b, Sig2c input to the conversion unit 23 are switches 35a, 35b, 35c and switches 36a, 36b provided for the respective signals. , 36c are sequentially input to the A / D conversion circuit 31. The switches 35a, 35b, and 35c and the switches 36a, 36b, and 36c are sequentially turned on by a switch control signal Ctr output from a control unit (not shown).

  In other words, the switches 35a, 35b, and 35c and the switches 36a, 36b, and 36c provided in the conversion unit 23 are turned on at a certain time t and all other switches are turned off, and the A / D conversion circuit 31 is turned off. The first signal Sig1a is input, the switch 36a is turned on at time t + 1, all other switches are turned off, the second signal Sig2a is input to the A / D conversion circuit 31, and the switch 35b is turned on at time t + 2. All the other switches become non-conductive, the first signal Sig1b is input to the A / D conversion circuit 31, the switch 36b becomes conductive at time t + 3, and all the other switches become non-conductive, and the A / D conversion The second signal Sig2b is input to the circuit 31, the switch 35c is turned on at time t + 4, and all the other switches are not turned on. The first signal Sig1c is input to the A / D conversion circuit 31, the switch 36c is turned on at time t + 5, all other switches are turned off, and the second signal Sig2c is input to the A / D conversion circuit 31. At time t + 6, the switch 35 a is turned on again, all the other switches are turned off, and the first signal Sig 1 a is input to the A / D conversion circuit 31. Thereafter, by repeating this, the first signal Sig1a, Sig1b, Sig1c and the second signal Sig2a, Sig2b, Sig2c are input to the A / D conversion circuit 31 in a time division manner.

  The A / D conversion circuit 31 converts the first signals Sig1a, Sig1b, Sig1c and the second signals Sig2a, Sig2b, Sig2c inputted in time division into digital signals. At this time, the digital signal converted by the A / D conversion circuit 31 is interlocked with the switch control signal Ctr and sequentially held in the registers 32a, 32b, 32c or the registers 33a, 33b, 33c. As a result, the first signals Sig1a, Sig1b, Sig1c and the second signals Sig2a, Sig2b, Sig2c A / D-converted in a time division manner are converted into digital signals, and sequentially registered in accordance with the switch control signal Ctr, the registers 32a, 32b, 32c or the registers 33a, 33b, 33c.

  For example, at a certain time t, the digital signal obtained by A / D converting the first signal Sig1a is held in the register 32a, and at the time t + 1, the digital signal obtained by A / D converting the second signal Sig2a is held in the register 33a. At time t + 2, the digital signal obtained by A / D conversion of the first signal Sig1b is held in the register 32b. At time t + 3, the digital signal obtained by A / D conversion of the second signal Sig2b is held in the register 33b. At t + 4, the digital signal obtained by A / D converting the first signal Sig1c is held in the register 32b. At time t + 5, the digital signal obtained by A / D converting the second signal Sig2c is held in the register 33b, and at time t + 6. The digital signal obtained by A / D converting the first signal Sig1a is Holding monkey to fine-register 32a. That is, the signal held in the register 32a is the first digital signal Dig1a, the signal held in the register 33a is the second digital signal Dig2a, and the signal held in the register 32b is the first digital signal Dig1b. The signal held in the register 33b is the second digital signal Dig2b, the signal held in the register 32c is the first digital signal Dig1c, and the signal held in the register 33c is the second digital signal. Dig2c.

  Similarly to the first embodiment, the digital signals held in the respective registers are input to the signal processing unit 24, and based on the first digital signal Dig1a and the second digital signal Dig2a, the X-axis angular velocity and the Z-axis acceleration. Y-axis angular velocity and Z-axis acceleration are calculated based on the first digital signal Dig1b and the second digital signal Dig2b, and Z-axis angular velocity is calculated based on the first digital signal Dig1c and the second digital signal Dig2c. And X-axis acceleration is calculated. Then, the signal processing unit 24 sequentially outputs the calculated angular velocities of the X axis, the Y axis, and the Z axis as the angular velocity signal VD1. Further, the signal processing unit 24 sequentially outputs, for example, the average of two calculated Z-axis accelerations as the Z-axis acceleration and the calculated X-axis and Z-axis accelerations as VD2.

  Note that details of the signal processing unit 24 and the interface circuit 25 are the same as those in the first embodiment, and thus the description thereof is omitted.

  According to the present embodiment, the conversion unit 23 performs A / D conversion of the first signals Sig1a, Sig1b, Sig1c and the second signals Sig2a, Sig2b, Sig2c in a time-sharing manner, whereby the first digital signals Dig1a, Dig1b, The calculation process of Dig1c and the calculation process of the second digital signals Dig2a, Dig2b, Dig2c are performed in a pseudo parallel manner. Also in the second embodiment, as in the first embodiment, the signal processing unit 24 performs the calculation of the angular velocity and the acceleration by digital processing, so that the calculation of the angular velocity and the acceleration is less likely to be affected by noise and the like. It becomes.

  FIG. 11 is a block diagram illustrating a modification of the charge amplifier 21, the charge amplifier 22, and the conversion unit 23 included in the detection circuit 20 in the second embodiment. This modification differs in the structure of 2nd Embodiment and the conversion part 23. FIG.

  Specifically, the first signal Sig1a and the second signal Sig2a are input to the A / D conversion circuit 31a in a time division manner by the switch 35a and the switch 36a controlled by a switch control signal Ctra output from a control unit (not shown). And converted into a digital signal. The digital signal converted by the A / D conversion circuit 31a is synchronized with the switch control signal Ctra, held in the registers 32a and 33a in a time division manner, and then converted into the first digital signal Dig1a and the second digital signal Dig2a. The signal is input to the signal processing unit 24.

  Similarly, the first signal Sig1b and the second signal Sig2b are input to the A / D conversion circuit 31b in a time division manner by the switch 35b and the switch 36b controlled by a switch control signal Ctrb output from a control unit (not shown). Converted to a digital signal. The digital signal converted by the A / D conversion circuit 31b is synchronized with the switch control signal Ctrb and held in the registers 32b and 33b in a time-sharing manner, and then converted into the first digital signal Dig1b and the second digital signal Dig2b. The signal is input to the signal processing unit 24.

  Similarly, the first signal Sig1c and the second signal Sig2c are input to the A / D conversion circuit 31c in a time division manner by the switch 35c and the switch 36c controlled by a switch control signal Ctrc output from a control unit (not shown). Converted to a digital signal. The digital signal converted by the A / D conversion circuit 31c is synchronized with the switch control signal Ctrc and held in the registers 32c and 33c in a time-division manner, and then converted into the first digital signal Dig1c and the second digital signal Dig2c, The signal is input to the signal processing unit 24.

  According to this modification, the A / D conversion sampling rate can be lowered by providing the A / D conversion circuits 31 individually for the plurality of vibration elements 100 provided. Specifically, the sampling rate of the A / D conversion is desirably 10 times or more the upper limit frequency of the signal band (hereinafter referred to as “sensor band”) that can be detected by the physical quantity sensor 1. When the upper limit frequency is 100 Hz, 1 kHz or more per detection axis is desirable. Furthermore, when a quick detection operation is required in the application of the physical quantity sensor 1, it is desirable that the upper limit frequency of the sensor band of the physical quantity sensor 1 is 50 times or more. For example, when the upper limit frequency of the sensor band is 100 Hz, 5 kHz or more is desirable per detection axis.

  Further, in detecting the angular velocity, it is desirable that the driving frequency of the driving signal DRV for driving and vibrating the vibration element 100 is 10 times or more. For example, when the driving frequency is 50 kHz, the sampling rate of A / D conversion Is preferably 500 kHz or more per detection axis. Furthermore, when a quick detection operation is required in the use of the physical quantity sensor 1, it is desirable that the drive frequency of the drive signal DRV for driving and vibrating the vibration element 100 is 50 times or more. For example, the upper limit frequency of the sensor band is 50 kHz. In this case, 2.5 MHz or more per detection axis is desirable.

  For example, in the physical quantity sensor 1 that detects two axes of angular velocity and acceleration, the required A / D conversion sampling rate may be at least twice the upper limit frequency of the sensor band or the higher drive frequency of the drive signal DRV. desirable. Specifically, in the case of the physical quantity sensor 1 that detects an upper limit frequency of the sensor band of 100 Hz, a drive frequency of the drive signal DRV of 50 kHz, and detects angular velocity and acceleration, a sampling rate of 50 kHz × 10 times × two axes = 1 MHz or higher is desirable. Furthermore, in the case of the physical quantity sensor 1 provided with three vibration elements 100 as in the second embodiment, a sampling rate of 3 MHz or higher, which is three times that, is desirable.

  That is, in this modification, in the physical quantity sensor 1 provided with three vibration elements 100, the A / D conversion circuits 31a, 31b, and 31c are individually provided, so that the detection axis per one A / D conversion circuit is provided. The number can be reduced, and the sampling rate can be suppressed. Thereby, power saving of the physical quantity sensor 1 can be achieved.

  According to the second embodiment, by mounting the three vibration elements 100 on the physical quantity sensor 1, the physical quantity sensor 1 capable of detecting five axes (three-axis angular velocity and two-axis acceleration) can be realized. . Furthermore, by converting the detection signal from each vibration element 100 into a digital signal in a time-sharing manner and calculating the angular velocity and acceleration by digital processing, it is possible to realize a 5-axis physical quantity sensor that is not easily affected by noise or the like. Become.

1.3 Third Embodiment In the physical quantity sensor 1 of the second embodiment, the three-axis angular velocity and the two-axis acceleration are calculated by using three vibrating elements 100. However, the physical quantity sensor of the third embodiment 1 calculates the triaxial angular velocity and the triaxial acceleration by changing the cross-sectional shape of the H-type vibration element 100-2. In the physical quantity sensor 1 of the third embodiment, the same components as those in the first embodiment and the second embodiment are denoted by the same reference numerals, and differences from the first embodiment and the second embodiment will be described. The description which overlaps with 1st Embodiment or 2nd Embodiment is abbreviate | omitted.

  Although not shown, the physical quantity sensor 1 according to the third embodiment is similar to the second embodiment (FIG. 8) in that a box-like base 300 having one surface opened and a plate-like shape that closes the opening surface of the base 300. The lid includes a first vibration element 100a, a second vibration element 100b, a third vibration element 100c, and an IC2 (not illustrated). The physical quantity sensor 1 includes a first vibration element 100a, a second vibration element 100b, a third vibration element 100c, and a package (not shown) that are hermetically sealed with a box-shaped base 300 and a lid. IC2 is arranged. Note that the first vibration element 100a, the second vibration element 100b, and the third vibration element 100c in the third embodiment are arranged in the same manner as in the second embodiment.

  Since the functional blocks of the physical quantity sensor 1 in the third embodiment are the same as those in the first embodiment (FIG. 1) and the second embodiment (FIGS. 9 and 10), their illustration and description are omitted.

  The third vibration element 100c in the third embodiment is a double T-type vibration element 100-1 similar to that in the second embodiment, and the structure and operation are the same as those in the first embodiment (FIGS. 2 to 4B). Therefore, illustration and description thereof are omitted.

  The first vibration element 100a and the second vibration element 100b in the third embodiment are H-type vibration elements 100-2. The drive vibration (FIGS. 5A and 5B) based on the drive signal DRV is the same as in the first embodiment, and the angular velocity detection (FIGS. 6A and 6B) is also the same as in the first embodiment. The description is omitted. In the third embodiment, the first vibrating element 100a and the second vibrating element 100b have different cross-sectional shapes of the detection vibrating arms 123 and 124. Furthermore, the acceleration detection method is also different from the first embodiment and the second embodiment. Details will be described below.

  FIG. 12 is a plan view schematically showing the shape of the H-type vibration element 100-2 of the first vibration element 100a and the second vibration element 100b in the third embodiment. 13A, 13B, and 13C are cross-sectional views showing the A-A ′ cross section (xz cross section) of FIG. 12 in the detection vibration arm 123 of the H-type vibration element 100-2 in the third embodiment. FIGS. 12, 13A, 13B, and 13C are the same axes as FIGS. 5A, 5B, 6A, and 7A, and illustrate three axes that are orthogonal to each other, the x axis, the y axis, and the z axis. ing. That is, the xz cross-sectional shape of the detection vibrating arm 123 shown in FIGS. 13A, 13B, and 13C corresponds to the xz cross-sectional views in FIGS. 5A, 5B, 6A, and 7A. The first vibration element 100a and the second vibration element 100b are both H-type vibration elements 100-2, and the structure and operation will be described using common reference numerals.

  Furthermore, in the third embodiment, the detection vibrating arm 123 and the detection vibrating arm 124 are the same in configuration, except that the detection electrode formed is the first detection electrode 121 or the second detection electrode 122. Therefore, in the third embodiment, the detection vibrating arm 123 will be described representatively.

  As shown in FIG. 13A, the xz cross section (FIG. 12A-A ′ cross section) of the detection vibrating arm 123 of the vibration element 100-2 in the third embodiment is the main surface 180 side and the main surface 180 of the vibration element 100-2. On the opposite surface, bottomed grooves 210 and 211 are formed, respectively. That is, the xz cross-sectional shape of the detection vibrating arm 123 is substantially H-shaped.

  The inner surface of the groove 210 includes inclined surfaces 210A, 210B, 210C and a surface 210D that are inclined with respect to the z-axis.

  The inclined surface 210 </ b> A is located on the most −x side of the inner surface of the groove 210. Further, the angle θ1 formed by the inclined surface 210A and the yz plane is about 20 to 25 °.

  The inclined surface 210B is located on the + x side of the inclined surface 210A. Further, the angle θ2 formed by the inclined surface 210B and the yz plane is about 55 to 65 °.

  The inclined surface 210C is located on the + x side of the inclined surface 210B. Further, the angle θ3 formed by the inclined surface 210C and the yz plane is about 65 to 75 °.

  The surface 210D is located on the most + x side of the inner surface of the groove 210. In addition, the surface 210D is configured by a plane having the z axis as a normal line.

  The inner surface of the groove 211 includes inclined surfaces 211A, 211B, 211C, and a surface 211D that are inclined with respect to the z-axis.

  The inclined surface 211A is located closest to the −x side of the inner surface of the groove 211. Further, the angle θ4 formed by the inclined surface 211A and the yz plane is about 20 to 25 °.

  The inclined surface 211B is located on the + x side of the inclined surface 211A. The angle θ5 formed by the inclined surface 211B and the yz plane is about 55 to 65 °.

  The inclined surface 211C is located on the + x side of the inclined surface 211B. Further, an angle θ6 formed by the inclined surface 211C and the yz plane is about 65 to 75 °.

  The surface 211D is located closest to the + x side of the inner surface of the groove 211. In addition, the surface 211D is configured by a plane having the z axis as a normal line.

  The first detection electrode 121 is provided on the inclined surfaces 211A and 211B and the surface 210D. The common electrode 125 is continuously provided on the −x side surface, the surface 212, and the inclined surfaces 210A and 210B of the detection vibrating arm 123, and is further continuous with the + x side surface, the surface 213, and the surface 211D of the detection vibrating arm 123. Is provided.

  In the third embodiment, as shown in FIG. 13B, when the acceleration 151 in the direction along the second detection axis 170 substantially perpendicular to the x axis is applied, the detection vibrating arm 123 has arrows a, b, c, Electric fields indicated by d are respectively generated. However, the electric fields indicated by arrows a and d are electric fields generated between the common electrodes 125 and are not detected by the first detection electrode 121. Therefore, AC charges based on the electric fields indicated by the arrows b and d are output to the first detection electrode 121.

  In the third embodiment, the second detection electrode 122 and the common electrode 125 formed on the detection vibrating arm 124 are the same as the first detection electrode 121 and the common electrode 125 formed on the detection vibrating arm 123 shown in FIG. 13A. When the acceleration 151 in the direction along the second detection axis 170 is applied, the detection vibration arm 123 and the detection vibration arm 124 perform the same operation. That is, when the acceleration 151 in the direction along the second detection axis 170 is applied, the AC charges output from the first detection electrode 121 and the second detection electrode 122 are in phase.

  In the third embodiment, as shown in FIG. 13C, when the acceleration 151 in the direction along the third detection axis 175 substantially horizontal to the x axis is applied, the detection vibrating arm 123 has arrows e, f, g, Electric fields indicated by h are generated respectively. However, the electric fields indicated by arrows e and f are electric fields generated between the common electrodes 125 and are not detected by the first detection electrode 121. Therefore, AC charges based on the electric fields indicated by the arrows f and g are output to the first detection electrode 121.

  In the third embodiment, the second detection electrode 122 and the common electrode 125 formed on the detection vibrating arm 124 are the same as the first detection electrode 121 and the common electrode 125 formed on the detection vibrating arm 123 shown in FIG. 13A. When the acceleration 151 in the direction along the third detection axis 175 is applied, the detection vibrating arm 123 and the detection vibrating arm 124 perform the same operation. That is, when the acceleration 151 in the direction along the third detection axis 175 is applied, the AC charges output from the first detection electrode 121 and the second detection electrode 122 are in phase.

  As a result, the vibration element 100-2 of the third embodiment has an acceleration in the direction of the second detection axis 170 (z axis) in addition to the angular velocity generated around the first detection axis 160 (y axis), and further the third detection axis. The acceleration in the direction 175 (x axis) can be detected.

  FIG. 14 shows the relationship between a plurality of vibration elements 100 and physical quantities that can be detected in the physical quantity sensor 1 when the vibration element 100-2 of the third embodiment is used as the first vibration element 100a and the second vibration element 100b. FIG.

  As illustrated in FIG. 14, the physical quantity sensor 1 according to the third embodiment detects the X-axis angular velocity based on signals of opposite phases from the first detection electrode 121a and the second detection electrode 122a of the first vibration element 100a. The axial angular velocity is detected based on signals in reverse phase between the first detection electrode 121b and the second detection electrode 122b of the second vibration element 100b, and the Z-axis angular velocity is detected with the first detection electrode 121c and the second detection signal of the third vibration element 100c. It can be detected by a signal in reverse phase with the detection electrode 122c. Furthermore, the physical quantity sensor 1 according to the third embodiment uses the same phase signal of the first detection electrode 121b and the second detection electrode 122b of the second vibration element 100b as the X-axis acceleration and the first detection electrode of the third vibration element 100c. The Y-axis acceleration is detected by the in-phase signal between the first detection electrode 121a and the second detection electrode 122a of the first vibration element 100a, and is detected by the in-phase signal between the 121c and the second detection electrode 122c. Is detected by the in-phase signal of the first detection electrode 121a and the second detection electrode 122a of the first vibration element 100a and the in-phase signal of the first detection electrode 121b and the second detection electrode 122b of the second vibration element 100b. be able to.

  In the physical quantity sensor 1 according to the third embodiment, for example, the first vibration element 100a detects the Z-axis acceleration in addition to the Y-axis acceleration. That is, in the physical quantity sensor 1 according to the third embodiment, for example, it is impossible to determine whether the detected physical quantity is the Y-axis acceleration or the Z-axis acceleration only from the detection signal of the first vibration element 100a. For this reason, in the present embodiment, the triaxial acceleration is calculated by calculating the acceleration detected by the plurality of vibration elements 100 using the following calculation formula.

  Specifically, assuming that the acceleration detected by the first vibration element 100a is Vacc1, the acceleration detected by the second vibration element 100b is Vacc2, and the acceleration detected by the third vibration element 100c is Vacc3, the acceleration of each axis. Is calculated as follows.

  According to the third embodiment, when the vibration element 100 capable of detecting biaxial acceleration is used for the first vibration element 100a and the second vibration element 100b of the physical quantity sensor 1, six axes (three axes) The physical quantity sensor 1 capable of detecting the angular velocity and the triaxial acceleration) can be realized. Furthermore, by converting detection signals from each vibration element 100 into digital signals in a time-sharing manner and calculating angular velocity and acceleration by digital processing, it is possible to realize a 6-axis physical quantity sensor that is not easily affected by noise or the like. Become.

1.4 Fourth Embodiment In the fourth embodiment, in the physical quantity sensor 1 of the second embodiment, the triaxial angular velocity that enables detection of the Y axis acceleration by changing the arrangement of the first vibration element 100a. And 3-axis acceleration is calculated.

In the physical quantity sensor 1 of the fourth embodiment, the same reference numerals are given to the same components as those of the first embodiment, the second embodiment, and the third embodiment, and the first embodiment, the second embodiment, and Differences from the third embodiment will be described, and descriptions overlapping with the first embodiment, the second embodiment, or the third embodiment will be omitted.

  FIG. 15 is a perspective view of the physical quantity sensor 1 in the fourth embodiment. In the figure shown in FIG. 15, the X axis, the Y axis, and the Z axis are shown as three axes orthogonal to each other.

  The physical quantity sensor 1 according to the fourth embodiment includes a box-shaped base 300 having one surface opened, a plate-shaped lid (not shown) that closes the opening surface of the base 300, a first vibration element 100a, and a second vibration element. 100b, the 3rd vibration element 100c, and IC2 not shown are comprised. The physical quantity sensor 1 includes a first vibration element 100a, a second vibration element 100b, a third vibration element 100c, and a package (not shown) that are hermetically sealed with a box-shaped base 300 and a lid. IC2 is arranged.

  The first vibration element 100a is an H-type vibration element 100-2 shown in FIGS. 5A to 7B. In the first vibrating element 100a, the first detection shaft 160 shown in FIG. 6A and the second detection shaft 170 shown in FIG. 7A are arranged along the X axis and the Y axis in FIG. That is, the first vibration element 100a is provided on the inner surface of the box-shaped base 300 so that the main surface 180 of the H-shaped vibration element 100-2 is substantially horizontal with respect to the XZ plane shown in FIG. Thereby, the first vibration element 100a can detect the angular velocity around the first detection axis 160 along the X axis and the acceleration in the direction of the second detection axis 170 along the Y axis in FIG.

  The second vibration element 100b is an H-type vibration element 100-2 shown in FIGS. 5A to 7B. In the second vibration element 100b, the first detection shaft 160 shown in FIG. 6A and the second detection shaft 170 shown in FIG. 7A are arranged along the Y axis and the Z axis in FIG. 15, respectively. That is, the second vibration element 100b can detect the angular velocity around the first detection axis 160 along the Y axis and the acceleration in the direction of the second detection axis 170 along the Z axis in FIG.

  The third vibrating element 100c is a double T-shaped vibrating element 100-1 shown in FIGS. In the third vibrating element 100c, the first detection shaft 160 shown in FIG. 3A and the second detection shaft 170 shown in FIG. 4A are arranged along the Z axis and the X axis in FIG. That is, the third vibration element 100c can acquire the angular velocity around the first detection axis 160 along the Z axis and the acceleration in the direction of the second detection axis 170 along the X axis in FIG.

  Since the structure and operation of each of the plurality of vibration elements 100 in the fourth embodiment are the same as those in the first embodiment (FIGS. 2 to 7B), illustration and description thereof are omitted.

  The physical quantity sensor 1 in the fourth embodiment includes a drive circuit 10, a conversion unit 23, a signal processing unit 24, an interface circuit 25, and an A / D conversion circuit 26 as in the first embodiment (FIG. 1). Further, the physical quantity sensor 1 includes three sets of charge amplifiers 21a, 22a, 21b, 22b, 21c, and 22c as in the second embodiment (FIGS. 9 and 10).

  FIG. 16 is a diagram illustrating a relationship between a plurality of vibration elements 100 of the physical quantity sensor 1 and detectable physical quantities in the fourth embodiment.

As shown in FIG. 15, the physical quantity sensor 1 in the fourth embodiment detects the X-axis angular velocity based on the reverse phase signals of the first detection electrode 121a and the second detection electrode 122a of the first vibration element 100a, and Y The axial angular velocity is detected based on signals in reverse phase between the first detection electrode 121b and the second detection electrode 122b of the second vibration element 100b, and the Z-axis angular velocity is detected with the first detection electrode 121c and the second detection signal of the third vibration element 100c. It can be detected by a signal having a phase opposite to that of the detection electrode 122c. Furthermore, the physical quantity sensor 1 according to the fourth embodiment detects the X-axis acceleration based on the in-phase signals of the first detection electrode 121c and the second detection electrode 122c of the third vibration element 100c, and the Y-axis acceleration is determined based on the first axis. The Z-axis acceleration is detected by the in-phase signal between the first detection electrode 121a and the second detection electrode 122a of the vibration element 100a, and the Z-axis acceleration is detected in the same phase between the first detection electrode 121b and the second detection electrode 122b of the second vibration element 100b. It can be detected by a signal.

  According to the fourth embodiment, by three-dimensionally mounting the three vibration elements 100 on the physical quantity sensor 1, the physical quantity sensor 1 has the X-axis, Y-axis, and Z-axis angular velocities (three-axis angular velocities) and the X-axis. , 6-axis sensor capable of detecting Y-axis and Z-axis acceleration (3-axis acceleration).

  According to the fourth embodiment, the physical quantity sensor 1 capable of detecting six axes (three-axis angular velocity and three-axis acceleration) is realized by three-dimensionally mounting the three vibration elements 100 on the physical quantity sensor 1. be able to. Furthermore, by converting detection signals from each vibration element 100 into digital signals in a time-sharing manner and calculating angular velocity and acceleration by digital processing, it is possible to realize a 6-axis physical quantity sensor that is not easily affected by noise or the like. Become.

2. Next, an electronic device according to the present embodiment will be described with reference to the drawings. The electronic device according to the present embodiment includes the physical quantity sensor according to the present invention. Hereinafter, an electronic apparatus including the physical quantity detection device 400 will be described as a physical quantity sensor according to the present invention.

  FIG. 17 is a perspective view schematically showing a mobile (or notebook) personal computer 1100 as the electronic apparatus according to the present embodiment.

  As shown in FIG. 17, the personal computer 1100 includes a main body portion 1104 having a keyboard 1102 and a display unit 1106 having a display portion 1108. The display unit 1106 has a hinge structure portion with respect to the main body portion 1104. It is supported so that rotation is possible.

  Such a personal computer 1100 incorporates a physical quantity detection device 400.

  FIG. 18 is a perspective view schematically showing a mobile phone (including PHS) 1200 as the electronic apparatus according to the present embodiment.

  As shown in FIG. 18, the mobile phone 1200 includes a plurality of operation buttons 1202, an earpiece 1204, and a mouthpiece 1206, and a display unit 1208 is disposed between the operation buttons 1202 and the earpiece 1204. .

  Such a cellular phone 1200 incorporates a physical quantity detection device 400.

  FIG. 19 is a perspective view schematically showing a digital still camera 1300 as an electronic apparatus according to the present embodiment. Note that FIG. 19 simply shows connection with an external device.

  Here, an ordinary camera sensitizes a silver halide photographic film with a light image of a subject, whereas a digital still camera 1300 photoelectrically converts a light image of a subject with an image sensor such as a CCD (Charge Coupled Device). An imaging signal (image signal) is generated.

  A display unit 1310 is provided on the back of a case (body) 1302 in the digital still camera 1300, and is configured to display based on an imaging signal from the CCD. The display unit 1310 displays an object as an electronic image. Functions as a viewfinder.

  A light receiving unit 1304 including an optical lens (imaging optical system), a CCD, and the like is provided on the front side (the back side in the drawing) of the case 1302.

  When the photographer confirms the subject image displayed on the display unit 1310 and presses the shutter button 1306, the CCD image pickup signal at that time is transferred and stored in the memory 1308.

  In the digital still camera 1300, a video signal output terminal 1312 and an input / output terminal 1314 for data communication are provided on the side surface of the case 1302. A television monitor 1430 is connected to the video signal output terminal 1312 and a personal computer 1440 is connected to the input / output terminal 1314 for data communication, if necessary. Further, the imaging signal stored in the memory 1308 is output to the television monitor 1430 or the personal computer 1440 by a predetermined operation.

  Such a digital still camera 1300 incorporates a physical quantity detection device 400.

  Note that the electronic apparatus provided with the physical quantity detection device 400 includes, for example, an ink jet type discharge in addition to the personal computer (mobile personal computer) shown in FIG. 17, the mobile phone shown in FIG. 18, and the digital still camera shown in FIG. Devices (for example, inkjet printers), laptop personal computers, televisions, video cameras, video tape recorders, various navigation devices, pagers, electronic notebooks (including those with communication functions), electronic dictionaries, calculators, electronic game machines, head-mounted displays , Word processor, workstation, video phone, security TV monitor, electronic binoculars, POS terminal, medical equipment (eg, electronic thermometer, blood pressure monitor, blood glucose meter, electrocardiogram measuring device, ultrasonic diagnostic device, electronic endoscope), fish school Machine Various measuring instruments, gauges (e.g., vehicles, aircraft, rockets, instruments and a ship), attitude control such as a robot or a human body, can be applied to a flight simulator.

  The electronic apparatus according to the present embodiment includes a physical quantity detection device 400 that can detect angular velocity and acceleration with stable characteristics while suppressing an increase in circuit scale. Therefore, a more reliable electronic device can be realized at a lower cost.

3. Next, the moving body according to the present embodiment will be described with reference to the drawings. The moving body according to the present embodiment includes the physical quantity sensor according to the present invention. Hereinafter, a moving body including the physical quantity detection device 400 will be described as a physical quantity sensor according to the present invention.

  FIG. 20 is a perspective view schematically showing an automobile 1500 as a moving body according to the present embodiment.

  The automobile 1500 has a physical quantity detection device 400 built therein. Specifically, as shown in FIG. 20, an electronic control unit (ECU) that controls an engine output by incorporating a vibration element 100 that detects an angular velocity of the automobile 1500 in a vehicle body 1502 of the automobile 1500. 1504 is mounted. In addition, the physical quantity detection device 400 can be widely applied to a vehicle body attitude control unit, an anti-lock brake system (ABS), an air bag, and a tire pressure monitoring system (TPMS). it can.

  The electronic apparatus according to the present embodiment includes a physical quantity detection device 400 that can detect angular velocity and acceleration with stable characteristics while suppressing an increase in circuit scale. Therefore, a more reliable electronic device can be realized at a lower cost.

  The present invention is not limited to the present embodiment, and various modifications can be made within the scope of the gist of the present invention.

4). Modification Example 4.1 Modification Example 1
In the first modification, the description of the same components as those in the first to fourth embodiments is omitted, and different points will be described.

  In the first modification, the physical quantity sensor 1 includes at least one of an acceleration component that is an opposite phase signal and an angular velocity component that is an in-phase signal, the first calculation process is a sum calculation, and the second calculation process May be a difference operation.

  Specifically, in the vibration element 100 according to the first embodiment, the AC charges output from the first detection electrode 121 and the second detection electrode 122 are the first detection electrode 121, the second detection electrode 122, and the common electrode. The polarity can be changed by the arrangement with 125.

  In the double T-type vibrating element 100-1, for example, the common electrode 125 provided on the driving vibration arm 114 side of the side surface 190 of the detection vibrating arm 124 is changed to the driving vibration arm 116 side of the side surface 190 of the detection vibrating arm 124. When the acceleration is detected, the first detection electrode 121 and the second detection electrode 122 of the double T-type vibrating element 100-1 output AC charges having opposite phases to each other when detecting acceleration, and are in phase with each other when detecting the angular velocity. The AC charge that is the signal is output.

  In the H-type vibrating element 100-2, for example, when the second detection electrode 122 provided on the main surface 180 side of the detection vibrating arm 124 is changed to the side opposite to the main surface 180 of the detection vibrating arm 124, H The first detection electrode 121 and the second detection electrode 122 of the vibration element 100-2 of the type output AC charges having opposite phases when acceleration is detected, and AC signals that are in phase with each other when angular velocity is detected. Outputs charge.

  According to this modification, by changing the arrangement of the electrodes provided in the vibration element 100, when the vibration element 100 detects the angular velocity, the AC charges output from the first detection electrode 121 and the second detection electrode 122 are in phase. In addition, when the vibration element 100 detects acceleration, the AC charges output from the first detection electrode 121 and the second detection electrode 122 can be in reverse phase.

  In general, by calculating the difference, the synchronization noise is removed (precisely reduced), and the detection accuracy can be improved. According to the first modification, since the angular velocity is calculated by the sum operation and the acceleration is calculated by the difference operation, it is possible to improve the accuracy of detecting the acceleration.

4.2 Modification 2
In the second modification, the description of the same components as those in the first to fourth embodiments is omitted, and different points will be described.

  The second modification may include a calculation setting unit that sets a calculation rate for sum calculation and a calculation rate for difference calculation. That is, the physical quantity sensor 1 may include a calculation setting unit for arbitrarily setting / changing the angular velocity and acceleration calculation rates calculated by the first calculation processing unit 43 and the second calculation processing unit 44.

  Specifically, for example, the signal processing unit 24 includes an operation setting unit, and the operation setting unit sets the calculation rate of the sum operation and the difference operation of the first operation processing unit 43 and the second operation processing unit 44. change. Furthermore, the calculation setting unit may include a storage unit that stores data for setting a calculation frequency (calculation rate).

  Specifically, the calculation setting unit determines the calculation frequency of the first calculation processing unit 43 and the second calculation processing unit 44 based on the calculation rate data stored in the storage unit. For example, in the physical quantity sensor 1 that detects angular velocity with high accuracy and detects acceleration auxiliary, the calculation rate of the first calculation processing unit 43 may be increased and the calculation rate of the second calculation processing unit 44 may be set low. it can.

  The storage unit may be, for example, a non-volatile memory, specifically, a mask ROM (read only memory), a PROM (programmable ROM), an EPROM (Erasable PROM), or the like. The calculation rate data stored in the storage unit may be configured to be changeable from the MCU 50, for example.

  According to the second modification, the calculation setting unit arbitrarily sets / changes the calculation frequency (calculation rate) of the sum calculation and the difference calculation executed by the first calculation processing unit 43 and the second calculation processing unit 44. Can do. Thereby, for example, in a device in which the physical quantity sensor 1 is used, when the angular velocity detection frequency is high and the acceleration detection frequency is low, the calculation rate of the first calculation processing unit 43 that calculates the angular velocity is increased, and the acceleration is increased. The calculation rate of the second calculation processing unit 44 for calculating can be lowered.

  That is, the physical quantity sensor 1 can arbitrarily calculate the angular velocity and acceleration according to the application, and can reduce unnecessary calculations and power consumption. Furthermore, according to the second modification, even when the angular velocity and acceleration detection frequency bands are greatly different, optimal calculation processing can be performed.

  The above-described embodiments and modifications are merely examples, and the present invention is not limited to these. For example, it is possible to appropriately combine each embodiment and each modification.

  The present invention includes configurations that are substantially the same as the configurations described in the embodiments (for example, configurations that have the same functions, methods, and results, or configurations that have the same objects and effects). In addition, the present invention includes a configuration that achieves the same effect as the configuration described in the embodiment or a configuration that can achieve the same object. In addition, the invention includes a configuration in which a known technique is added to the configuration described in the embodiment.

DESCRIPTION OF SYMBOLS 1 ... Physical quantity sensor, 2 ... IC, 10 ... Drive circuit, 11 ... Amplitude adjustment circuit, 12 ... I / V conversion circuit, 13 ... AC amplifier circuit, 20 ... Detection circuit, 21 ... Charge amplifier, 22 ... Charge amplifier, 23 ... Conversion unit, 24 ... Signal processing unit, 25 ... Interface circuit, 26 ... A / D conversion circuit, 31 ... A / D conversion circuit, 32, 33 ... Register, 35, 36 ... Switch, 41 ... Multiplication processing unit, 42 DESCRIPTION OF SYMBOLS ... Low-pass filter processing part, 43 ... 1st arithmetic processing part, 44 ... 2nd arithmetic processing part, 50 ... MCU, 100 ... Vibration element, 111 ... Drive input electrode, 112 ... Drive output electrode, 113, 114, 115, 116 ... driving vibration arm, 121 ... first detection electrode, 122 ... second detection electrode, 123, 124 ... detection vibration arm, 125 ... common electrode, 130 ... base, 131, 132 ... connection arm, 150 Angular velocity, 151 ... acceleration, 160 ... first detection axis, 170 ... second detection axis, 175 ... third detection axis, 180 ... main surface, 190 ... side surface, 210, 211 ... groove, 210A, 210B, 210C, 211A, 211B, 211C ... inclined surface, 210D, 211D ... surface, 212, 213 ... surface, 300 ... base, 400 ... physical quantity detection device, 1100 ... personal computer, 1102 ... keyboard, 1104 ... main body, 1106 ... display unit, 1108 ... Display unit 1200 ... Mobile phone 1202 ... Operation button 1204 ... Earpiece 1206 ... Mouthpiece 1208 ... Display unit 1300 ... Digital still camera 1302 ... Case 1304 ... Light receiving unit 1306 ... Shutter button 1308 ... Memory, 1310 ... Display section, 1312 ... Video signal output Child, 1314 ... Input / output terminal, 1430 ... TV monitor, 1440 ... Personal computer, 1500 ... Automobile, 1502 ... Car body, 1504 ... Electronic control unit, DRV ... Drive signal, Sig1 ... First signal, Sig2 ... Second signal, Dig1 ... first digital signal, Dig2 ... second digital signal, VD1 ... angular velocity signal, VD2 ... acceleration signal

Claims (9)

A vibration element including a first detection electrode and a second detection electrode;
A first amplifier for amplifying a signal from the first detection electrode;
A second amplifier for amplifying a signal from the second detection electrode;
A converter for converting a first signal from the first amplifier into a first digital signal and converting a second signal from the second amplifier into a second digital signal;
A signal processing unit that calculates angular velocity and acceleration based on the first digital signal and the second digital signal;
Including physical quantity sensor. The converter is
The physical quantity sensor according to claim 1, wherein the conversion of the first signal into the first digital signal and the conversion of the second signal into the second digital signal are performed in a time division manner. The signal processing unit
Multiplying the first digital signal by a reference signal based on a drive signal for driving the vibration element, and multiplying the second digital signal by the reference signal;
Low-pass filter processing for the signal obtained by the multiplication process;
A first calculation process for calculating an angular velocity by one of a sum calculation and a difference calculation of signals obtained by the low-pass filter process;
A second calculation process for calculating acceleration by the other of a sum calculation and a difference calculation of the first digital signal and the second digital signal;
The physical quantity sensor according to claim 1 or 2, wherein: The first signal and the second signal are:
Including at least one of an angular velocity component that is a component in opposite phase and an acceleration component that is a component in phase with each other,
The first calculation process is the difference calculation;
The second calculation process is the sum calculation.
The physical quantity sensor according to claim 3. The first signal and the second signal are:
Including at least one of an acceleration component that is a signal out of phase with each other and an angular velocity component that is a signal in phase with each other,
The first calculation process is the sum calculation,
The second calculation process is the difference calculation.
The physical quantity sensor according to claim 3. The signal processing unit
6. The physical quantity sensor according to claim 3, further comprising an operation setting unit that sets an operation rate for the sum operation and an operation rate for the difference operation. 7. The vibrating element is
The base,
A first detection arm connected to the base and formed with the first detection electrode;
A second detection arm connected to the base and formed with the second detection electrode;
A driving arm that vibrates,
Including
The drive arm vibrates in the direction along the main surface of the vibration element,
When an angular velocity around the first detection axis is applied, the first detection arm and the second detection arm vibrate so as to vibrate in opposite directions,
7. The device according to claim 1, wherein when acceleration in a second detection axis direction is applied, the first detection arm and the second detection arm vibrate so as to vibrate in the same direction. The physical quantity sensor described. The physical quantity sensor according to claim 1 is provided.
Electronics. The physical quantity sensor according to claim 1 is provided.
Moving body.

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