Gyro sensor

Abstract

To provide a gyro sensor which includes an oscillator having two oscillation modes, and which enables feedback control to have the oscillation axis and electrode axis of the oscillator matched when a voltage is applied, independently of mode match control.SOLUTION: A gyro sensor 1 includes first modulation units 113, 123 including PLL circuits 110, 120, which carry out a modulation based on the detection voltage VXP in first oscillation mode of a resonance frequency ω1 and a first drive signal, and a demodulation based on the detection voltage VYP in second oscillation mode of a resonance frequency ω2 and a second drive signal. A control unit 10 includes second demodulation units 114, 124 for performing a demodulation based on the detection voltage VXP and the second drive signal and a demodulation based on the detection voltage VYP and the first drive signal. The control unit 10 includes demodulation output arithmetic units 130, 140 for performing arithmetic operation based on the demodulation output of the first and second demodulation units, and exercises feedback control on the basis of the operation results of the demodulation output arithmetic units 130, 140 to have the oscillation axis and electrode axis of the oscillator 2 matched at voltage application time.SELECTED DRAWING: Figure 7

Description

Technical Field

[0001] The present disclosure relates to a gyro sensor.

Background Art

[0002] Conventionally, in a vibrating gyro sensor, it is known that the accuracy of the sensor can be improved by matching the resonance frequencies of two vibration modes excited in a vibrator, which is a sensor element, that is, by mode matching. Usually, unless the vibrator is subjected to special processing for adjusting the vibration mode, the vibration axis and the electrode axis are different, or the two resonance frequencies ω1 and ω2 are different. Hereinafter, for the sake of simplicity of explanation, the resonance frequency of the first vibration mode of the vibrator is simply referred to as "resonance frequency ω1", and the resonance frequency of the second vibration mode of the vibrator is simply referred to as "resonance frequency ω2". Also, in this specification, the two resonance frequencies ω1 and ω2 of the vibrator may be collectively referred to as "mode frequencies ω1 and ω2".

[0003] Therefore, in the case of an electrostatic drive type, mode matching uses the electric spring effect to adjust the state of the vibration mode by electrostatic force due to voltage application in order to improve the accuracy of the sensor, and thereby match the mode frequencies ω1 and ω2 (ω2 > ω1). Hereinafter, for the sake of convenience of explanation, the angle formed by the vibration axis and the electrode axis of the vibrator is denoted as θ ωα is denoted, the frequency difference between the mode frequencies is denoted as Δω α is denoted, and the angle formed by the vibration axis and the electrode axis and the difference in the mode frequencies when a voltage is applied when driving the vibrator are denoted as θ ωβ , Δω β is denoted, respectively.

[0004] Examples of the gyro sensor for constantly maintaining the above mode matching include those described in Patent Document 1. The gyro sensor described in Patent Document 1 includes a first PLL circuit that performs frequency control of a drive signal for vibrating the vibrator in the first vibration mode, and a second PLL circuit that performs frequency control of a drive signal for vibrating the vibrator in the second vibration mode. In this gyro sensor, in mode matching, the two resonance frequencies ω1 and ω2 of the vibrator are respectively the reference frequency ω refControl it so as to achieve. Note that PLL is an abbreviation of Phase Locked Loop and is also called a phase-locked loop.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0006] In Patent Document 1, a gyro sensor having two PLL circuits and always maintaining mode match is proposed. However, in order to satisfy the two conditions of ω2 - ω1 = Δω α = 0 and θ ωα = 0, special processing for adjusting the oscillation mode or careful voltage application is required in advance. However, in the case of a sensor element without special processing or the like and with Δω α ≠ 0 and θ ωα ≠ 0 in the initial state, in order to always maintain mode match, it is necessary to control θ β independently of Δω ωβ .

[0007] In view of the above points, the present disclosure aims to provide a gyro sensor capable of feedback control of θ α when applying a voltage to the oscillation mode, independently of the control of Δω, even when Δω ωα ≠ 0 and θ β ≠ 0 in the initial state. ωβ

Means for Solving the Problems

[0008] According to one aspect of the present disclosure, a gyro sensor includes an oscillator (2) having a first vibration mode and a second vibration mode with different resonance frequencies, a mounting substrate (3) having a plurality of electrodes (51) facing the oscillator, a first PLL circuit (110) for controlling the frequency of a drive signal for vibrating the oscillator in the first vibration mode, a second PLL circuit (120) for controlling the frequency of a drive signal for vibrating the oscillator in the second vibration mode, a radial direction passing through the center of the region surrounded by the plurality of electrodes and along the thickness direction of the mounting substrate, with two directions along the drive electrodes used for driving the first vibration mode and the second vibration mode among the plurality of electrodes as the electrode axes (X, Y), and two directions along the vibration direction of the first vibration mode and the second vibration mode among the directions along the radial direction as the vibration axes (x, y). Based on the first detection voltage (V XP ) from the electrode for detecting the vibration of the first vibration mode among the plurality of electrodes and the first drive signal of the frequency (ω1) for resonantly driving the first vibration mode output from the first PLL circuit, the first demodulated output (V Xi1 , V Xq1 ), and based on the second detection voltage (V YP ) from the electrode for detecting the vibration of the second vibration mode among the plurality of electrodes and the second drive signal of the frequency (ω2) for resonantly driving the second vibration mode output from the second PLL circuit, a first demodulation unit (113, 123) for calculating the second demodulated output (V Yi2 , V Yq2 ), a third demodulated output (V Xi2 , V Xq2 ) based on the first detection voltage and the second drive signal, and a fourth demodulated output (V Yi1 , V Yq1 ) based on the second detection voltage and the first drive signal, a second demodulation unit (114, 124) for calculating, a first demodulated output calculation unit (130) for calculating the amplitude and phase of the first vibration mode based on the first demodulated output and the third demodulated output, a second demodulated output calculation unit (140) for calculating the amplitude and phase of the second vibration mode based on the second demodulated output and the fourth demodulated output, and a control signal (V Q+, V Q- A control circuit (150) that outputs

[0009] Thus, the gyro sensor has two independent PLL circuits and a first demodulation unit that performs demodulation based on the first detection voltage and the first drive signal of the first vibration mode of the vibrator, and the second detection voltage and the second drive signal of the second vibration mode of the vibrator. Further, the gyro sensor has a second demodulation unit that performs demodulation based on the first detection voltage and the second drive signal, and demodulation based on the second detection voltage and the first drive signal. Furthermore, the gyro sensor includes a demodulation output calculation unit that calculates the amplitude and phase of the two vibration modes based on the demodulation outputs of the first and second demodulation units, and a control circuit that outputs a control signal for aligning the vibration axis and the electrode axis of the vibrator based on the input signal from the demodulation output calculation unit. Thus, in the initial state, the gyro sensor has a difference Δω in the two resonance frequencies of the vibrator α ≠0, and θ where the vibration axis and the electrode axis are misaligned ωα ≠0, even so, feedback control with θ ωβ =0 is possible based on the two types of demodulation units and their demodulation outputs.

[0010] Note that the reference numerals in parentheses attached to each component etc. show an example of the correspondence relationship between the component etc. and the specific components etc. described in the embodiments described later.

Brief Description of the Drawings

[0011]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

Figure 10

Figure 11

Figure 12

Figure 13

Figure 14

Figure 15

Embodiments for Carrying Out the Invention

[0012] Hereinafter, embodiments of the present disclosure will be described with reference to the drawings. In the following embodiments, parts that are the same or equivalent to each other are denoted by the same reference numerals and will be described.

[0013] (First Embodiment) The gyro sensor 1 of the first embodiment will be described with reference to the drawings.

[0014] 〔Basic Configuration〕 As shown in FIG. 1 for example, the gyro sensor 1 of this embodiment includes a vibrator 2 and a mounting substrate 3, and is provided with a sensor element in which the vibrator 2 is mounted on the mounting substrate 3. The gyro sensor 1 can detect the angular velocity and the rotated angle applied to the gyro sensor 1 based on the change in capacitance between a part of the thin vibrator 2 that can vibrate in the first vibration mode and the second vibration mode and a plurality of first electrode portions 51 on the mounting substrate 3. The gyro sensor 1 can be constantly controlled in mode matching by a control unit 10 described later.

[0015] As shown in FIG. 2 for example, the vibrator 2 is a three-dimensional substantially symmetric micro-vibrator including a curved surface portion 21 having an outer shape of a substantially hemispherical three-dimensional curved surface, and a mounting portion 22 extending from the vertex side of the virtual hemisphere formed by the curved surface portion 21 toward the center side of the hemisphere. The vibrator 2 has, for example, conductive films (not shown) formed on both the front and back surfaces, and voltage can be applied from the mounting substrate 3. And, for example, a rim 23 which is an end portion of the curved surface portion 21 opposite to the mounting portion 22 faces a plurality of first electrode portions 51, and the rim 23 vibrates in a resonance mode by the electrostatic force generated between the first electrode portion 51 and the rim 23.

[0016] Note that the vibrator 2 can be manufactured, for example, by preparing a plate material made of an arbitrary reflow material such as quartz and a mold having a bowl-shaped recess and a support portion located at the center of the recess, setting the plate material in the mold, reducing the pressure in the recess, and heating and softening it.

[0017] Also, as shown in FIG. 3 for example, the vibrator 2 may have a substantially disk shape having a disk-shaped portion and a columnar connection portion joined to the mounting substrate 3 at the center of the portion. In this case, the end portion in the disk-shaped portion in the hollow state of the vibrator 2 is the rim 23, and the portion is surrounded by a plurality of first electrode portions 51. Thus, the vibrator 2 may have a structure that can vibrate in the first vibration mode and the second vibration mode by a driving electrode among a plurality of first electrode portions 51, and may have other known structures in addition to the above structure.

[0018] As shown in, for example, FIGS. 1 and 2, the mounting substrate 3 includes a lower substrate 4 and an upper substrate 5, which are joined together. For example, the mounting substrate 3 is obtained by performing wiring film formation or the like on a lower substrate 4 made of borosilicate glass as an insulating material, and then anodically joining an upper substrate 5 made of silicon as a semiconductor material to the lower substrate 4 and performing patterning. The mounting substrate 3 has, for example, a plurality of first electrode portions 51 and second electrode portions 52 formed by performing dry etching such as DRIE (Deep Reactive Ion Etching) on the upper substrate 5 after anodic bonding. Also, when the vibrator 2 has the bird bath shape shown in FIG. 2, for example, an annular groove (not shown) along the rim 23 may be formed in the lower substrate 4 as necessary so as not to contact the rim 23.

[0019] The plurality of first electrode portions 51 face, for example, the rim 23 of the vibrator 2 and are arranged at equal intervals and separated from each other so as to form a single loop on the plane of the mounting substrate, and electrode films (not shown) are formed on their respective upper surfaces. The plurality of first electrode portions 51 are connected, for example, to wires (not shown) on the electrode film (not shown) and are electrically connected to an external circuit board or the like, enabling control of their potential. All of the plurality of first electrode portions 51 are spaced apart from the rim 23 of the vibrator 2 by a predetermined distance, and each forms a capacitor with the vibrator 2, enabling detection of the capacitance between the vibrator 2 and the first electrode portions 51. A part of the plurality of first electrode portions 51 serves as detection electrodes for detecting capacitance, and another part serves as drive electrodes for applying an electrostatic force to the rim 23 of the vibrator 2.

[0020] As shown in FIG. 1, for example, the second electrode portion 52 has a frame shape surrounding the plurality of first electrode portions 51. An electrode film (not shown) is formed on the upper surface, and a wire (not shown) is connected to the electrode film (not shown). The second electrode portion 52 is connected to a conductive film (not shown) of the vibrator 2 by wiring (not shown) or the like and is configured to be able to apply a voltage.

[0021] The above is the basic configuration of the sensor portion of the gyro sensor 1 of the present embodiment. The control unit 10 that executes the drive control of the gyro sensor 1 will be described later.

[0022] In addition, in FIG. 1, the case where the mounting substrate 3 has 16 first electrode portions 51 and one frame-shaped second electrode portion 52 is shown as a representative example, but it is not limited thereto. For the first electrode portion 51 and the second electrode portion 52, for example, the number, arrangement, shape, etc. may be appropriately changed.

[0023] 〔Vibration Model and Various Voltages of the First Electrode Portion〕 Next, the vibration model of the vibrator 2 and various voltages in the plurality of first electrode portions 51 will be described with reference to FIGS. 4 to 6. FIG. 6 shows the plurality of first electrode portions 51 in a top view of the mounting substrate 3, and the outline of the rim 23 of the vibrator 2 is shown by a two-dot chain line.

[0024] When the vibrator 2 is viewed from the normal direction with respect to the plane formed by the mounting substrate 3 (hereinafter referred to as "top view"), by applying a voltage to a part of the first electrode portion 51, for example, as shown in FIG. 4, the number of bellies and nodes in the vibration amplitude of the outline of the rim 23 becomes 2n each, and it enters a resonance state. n is an integer of 2 or more, and such a resonance state of the vibrator 2 is called the "wineglass mode". In addition, in FIG. 4, it is a resonance mode of n = 2 in the wineglass mode, and the vibration axes x and y and the electrode axes X and Y to be described later are shown as a representative example in a state where they coincide, but the vibrator 2 can also be vibrated in a higher-order wineglass mode of n = 3 or more.

[0025] Hereinafter, for convenience of explanation, as shown in FIG. 4, with the center position of the rim 23 in the top view as the center C, the radial direction with the virtual straight line along the thickness direction of the mounting substrate 3 passing through the center C as the axis is referred to as the "substrate radial direction", and the circumferential direction with the virtual straight line as the axis is referred to as the "substrate circumferential direction". Also, among the directions along the substrate radial direction, the direction passing through the position of the antinode of the vibration of the rim 23 of the vibrator 2 in the first vibration mode (resonant frequency ω1) is referred to as the "vibration axis x", and the direction passing through the position of the node is referred to as the "vibration axis y". At this time, in the wine glass mode where n = k (k: an integer of 2 or more), the angle formed by the vibration axis x and the vibration axis y is (360 / 4k)°. For example, in the wine glass mode where n = 2, the angle formed by the vibration axis x and the vibration axis y is 45°.

[0026] The plurality of first electrode portions 51 are arranged, for example, along the substrate circumferential direction so as to be separated from each other and to have substantially the same distance from the non-vibrating rim 23. Here, for convenience of explanation, as shown in FIG. 4, for example, one direction on the actual plane where the plurality of first electrode portions 51 are arranged is defined as the "X r direction", and the direction orthogonal to the X r direction on the same plane is defined as the "Y r direction", and the same plane is defined as the "X r Y r plane". Then, one direction in the X r Y r plane is defined as the "electrode axis X", and the direction in which the electrode axis X points when rotated counterclockwise by (360 / 4k)° along the substrate circumferential direction on the X r Y r plane is defined as the "electrode axis Y".

[0027] The vibrator 2 has, for example, as shown in FIG. 5, a mass point MP and springs S installed in the directions of the vibration axes x and y, and can be regarded as a vibrating body of a two-degree-of-freedom system that vibrates in a two-dimensional plane. FIG. 5 is an X r Y rThe vibration axes x and y and the electrode axes X and Y in the plane are each converted into a rectangular coordinate system, and the origins of the vibration axes x and y are made to coincide with the origins of the electrode axes X and Y. Usually, in a sensor element formed by mounting the vibrator 2 on the mounting substrate 3, unless special processing or the like is performed, the electrode axes X and Y and the vibration axes x and y are different, that is, the vibration axis and the electrode axis do not overlap. That is, if the angle formed by the electrode axes X and Y and the vibration axes x and y in the rectangular coordinate system shown in FIG. 5 is θ ω then, in the sensor element, usually, θ ω ≠0.

[0028] Also, the vibration axes x and y of the vibrator 2 respectively correspond to the vibration directions of the first vibration mode and the second vibration mode in which the mode frequencies ω1 and ω2 are different. That is, in the sensor element, unless special processing or the like is performed, usually, Δω, which is the difference between the mode frequencies ω1 and ω2 (>ω1), does not become zero, and Δω≠0. The gyro sensor 1 performs mode match control by a control unit 10 described later in order to improve the sensor accuracy.

[0029] Here, the equation of motion of the vibration model of the two-degree-of-freedom system shown in FIG. 5 is expressed by the following equation (1) in the case of the wineglass mode with n = 2.

[0030]

Equation

[0031] V in equation (1) XT , V YT , V Q+ , V Q- are respectively various voltages applied to the first electrode portion 51. V XT , V YT , V Q+ , V Q- and various voltages applied to the other first electrode portion 51 will be described later. τ in equation (1) is the time constant, θ τ is the angle formed by the damping axis and the electrode axis, Ω is the angular velocity input to the sensor element, ω is the resonance angular frequency of the vibrator 2, F x , F yIt is the force acting on the vibrator from the X and Y directions of the electrode axis. Specifically, ω1 and ω2 in equation (1) are the resonance frequencies in the x and y directions of the vibration axis before applying the voltage, respectively, and ω = (ω1 2 + ω2 2 ) / 2, ωΔω = (ω1 2 - ω2 2 ) / 2. For the time constant τ, the equations 1 / τ = {(1 / τ1) + (1 / τ2)} / 2 and Δ(1 / τ) = (1 / τ1) - (1 / τ2) hold. τ1 and τ2 are the decay time constants in the x and y directions of the vibration axis before applying the voltage. Also, λ in equation (1) is a conversion coefficient depending on the vibrator 2 and the electrode shape for converting the applied voltage into the effect of the electric spring.

[0032] Also, the mode frequencies ω1 and ω2 of the vibrator 2 are represented by the following equation (2). ω1,2 in equation (2) 2 are the resonance frequencies in the x and y directions of the vibration axis when the voltage is applied.

[0033]

Equation

[0034] The control unit 10 controls the above θ ωβ = 0 and Δω β = 0. For example, as shown in FIG. 6, it applies and detects various voltages to the plurality of first electrode portions 51. The applied voltage and the detected voltage of the plurality of first electrode portions 51 are, for example, V XD , VXT , V XP , V YD , V YT , V YP , V Q+ , V Q- is.

[0035] V XD is based on the signals output from the PLL circuit 120 and the AGC circuit 121 described later, and is a drive voltage for resonantly driving the vibrator 2 in the first vibration mode at the resonance frequency ω1. V XT is output from the PI circuit 122 described later, and controls the resonance frequency ω1 of the first vibration mode by loosening the spring S of the vibrator 2 in the electrode axis X direction by the electro-spring effect, and Δω β = 0 is an applied voltage for. V XP is the first detection voltage of the vibration in the electrode axis X of the vibrator 2. V XD , V XT , V XP corresponds to, for example, those located on the electrode axis X among the plurality of first electrode portions 51.

[0036] V YD is based on the signals output from the PLL circuit 110 and the AGC circuit 111 described later, and is a drive voltage for resonantly driving the vibrator 2 in the second vibration mode at the resonance frequency ω2. V YT is output from the PI circuit 112 described later, and controls the resonance frequency ω2 of the second vibration mode by loosening the spring S of the vibrator 2 in the electrode axis Y direction by the electro-spring effect, and Δω β = 0 is an applied voltage for. V YP is the second detection voltage of the vibration in the electrode axis Y of the vibrator 2, and is output from the first electrode portion 51 arranged on the vibration axis x. V YD , V YT , V YP corresponds to, for example, those located on the electrode axis Y among the plurality of first electrode portions 51.

[0037] Note that, V XT , V YTis applied to a part of the plurality of first electrode portions 51 for mode matching that makes the difference between the two mode frequencies of the vibrator 2 zero, and at least one of them is controlled by the control unit 10. Specifically, in mode matching, when the control unit 10 makes one of the two mode frequencies ω1 and ω2 of the vibrator 2, the higher frequency (for example, ω2), match the lower frequency (for example, ω1), the applied V XT and V YT is controlled for one of them. On the other hand, when the control unit 10 performs mode matching to match the two mode frequencies ω1 and ω2 of the vibrator 2 to a predetermined reference frequency ω ref respectively, the applied V XT and V YT are both controlled. Whether to control one of the applied V XT and V YT or both can be designed appropriately, and either is acceptable.

[0038] V Q+ and V Q- are control voltages for making the vibration axes x and y coincide with the electrode axes X and Y and making θ ωβ = 0, and are applied, for example, to those not on the electrode axes X and Y among the first electrode portions 51. V Q+ is a control voltage for rotating the vibration axes x and y clockwise when viewed from above, for example, as shown in FIG. 5. V Q- is a control voltage for rotating the vibration axes x and y counterclockwise when viewed from above. V Q+ and V Q- are both applied to one of the first electrode portions 51, but in accordance with the direction of the deviation between the vibration axes x and y and the electrode axes X and Y, in order to rotate the vibration axes x and y in the direction opposite to the deviation direction, one of them is controlled.

[0039] 〔Control Unit〕 Next, the control unit 10 of the gyro sensor 1 will be described.

[0040] Hereinafter, for convenience of explanation, as shown in FIG. 7, the sensor element composed of the oscillator 2 and the mounting substrate 3 shown in FIG. 1 and a circuit (not shown) used for applying a voltage to the plurality of first electrode portions 51 are collectively referred to as the "sensor unit". Examples of the circuit not shown here include a current-voltage conversion circuit, a DAC, an ADC, and the like. In FIG. 6, for easy viewing, V Q+ and V Q- are collectively denoted as "V Q ". The voltages V XD , V XT , V YD , V YT , V Q applied to the sensor unit in FIG. 7 and the detection voltages V XP , V YP from the sensor unit correspond to the various voltages of the first electrode portion 51 described above.

[0041] The control unit 10 is, for example, an electronic control unit in which various electronic components such as a CPU, a ROM, and a RAM are mounted on a circuit board (not shown) and which executes drive control of the gyro sensor 1. CPU is an abbreviation for Central Processing Unit, ROM is an abbreviation for Read Only Memory, and RAM is an abbreviation for Random Access Memory. The control unit 10 includes, for example, as shown in FIG. 7, two PLL circuits 110, 120, two AGC circuits 111, 121, two PI circuits 112, 122, and two first demodulation units 113, 123. AGC is an abbreviation for Automatic Gain Control and is also referred to as automatic gain control. PI is an abbreviation for Proportional Integral.

[0042] The PLL circuit 110, the AGC circuit 111, the PI circuit 112, and the first demodulation unit 113 execute control of the resonance frequency ω1 and the amplitude of one of the two vibration modes of the oscillator 2, for example. The PLL circuit 120, the AGC circuit 121, the PI circuit 122, and the first demodulation unit 123 execute control of the resonance frequency ω2 and the amplitude in the remaining one vibration mode of the oscillator 2.

[0043] The PLL circuit 110 has, for example, an oscillation circuit that generates a drive signal of a predetermined frequency (not shown), and performs frequency control of the drive signal so as to resonantly drive the vibrator 2 at the resonance frequency ω1. The PLL circuit 110 performs the above-described frequency control based on an input signal regarding the phase information of the first vibration mode obtained by demodulating the detection voltage V XP by the first demodulation unit 113. The AGC circuit 111 controls, for example, the amplitude of the first vibration mode of the vibrator 2 based on an input signal from the first demodulation unit 113. The PI circuit 112 adjusts, for example, the resonance frequency ω1 of the first vibration mode of the vibrator 2 based on the output signal of the PLL circuit 110, and controls Δω β = 0. The first demodulation unit 113 receives, for example, the detection voltage V XP and the output signal from the PLL circuit 110, and performs demodulation corresponding to the resonance frequency ω1. The first demodulation unit 113 acquires, for example, information on the phase φ1 and amplitude R1 of the detection signal corresponding to the first vibration mode by demodulation, and feeds back the information on the phase φ1 to the PLL circuit 110 and the information on the amplitude R1 to the AGC circuit 111, respectively. The first demodulation unit 113 outputs, for example, a demodulation output corresponding to the resonance frequency ω1 to a first demodulation output calculation unit 130 described later.

[0044] Note that the PLL circuit 120, the AGC circuit 121, the PI circuit 122, and the first demodulation unit 123 correspond to the second vibration mode of the vibrator 2 and the resonance frequency ω2, and perform the same processing as the PLL circuit 110, the AGC circuit 111, the PI circuit 112, and the first demodulation unit 113, respectively. The PLL circuit 120 has, for example, an oscillation circuit (not shown), and performs frequency control of the drive signal to drive the vibrator 2 in the second vibration mode at the resonance frequency ω2 based on an input signal from the first demodulation unit 123. The first demodulation unit 123 acquires information on the phase φ2 and amplitude R2 of the detection signal corresponding to the second vibration mode by demodulation, and feeds back the information on the phase φ2 to the PLL circuit 120 and the information on the amplitude R2 to the AGC circuit 121, respectively. Then, the first demodulation unit 123 outputs, for example, a demodulation output corresponding to the resonance frequency ω2 to a second demodulation output calculation unit 140 described later. Further, the control unit 10, for example, a signal V corresponding to the angular velocity input from the AGC circuit 111 or the AGC circuit 121 to the sensor unitΩ+ and outputs V Ω- .

[0045] The control unit 10 further includes, for example, two second demodulation units 114 and 124, a first demodulation output calculation unit 130, a second demodulation output calculation unit 140, and a control circuit 150.

[0046] The second demodulation unit 114 acquires information on the resonance frequency ω2 of the second oscillation mode based on the drive signal output from the second PLL circuit 120, and performs demodulation corresponding to the resonance frequency ω2 based on the detection voltage V XP of the first oscillation mode. This is because in a system where the resonance driving of the mode frequencies ω1 and ω2 of the vibrator 2 is maintained by two independent PLL circuits 110 and 120, the detection voltage V XP includes information about the vibration amplitude in the y-axis direction of the second oscillation mode. The second demodulation unit 114 inputs the demodulation output to the first demodulation output calculation unit 130.

[0047] The second demodulation unit 124 acquires information on the resonance frequency ω1 of the first oscillation mode based on the drive signal output from the first PLL circuit 110, and performs demodulation corresponding to the resonance frequency ω1 based on the detection voltage V YP of the second oscillation mode. This demodulation is possible because, similar to the above, the detection voltage V YP includes information about the vibration amplitude in the x-axis direction of the first oscillation mode. The second demodulation unit 124 inputs the demodulation output to the second demodulation output calculation unit 140.

[0048] The first demodulation output calculation unit 130 performs calculations for controlling θ XP to 0 based on the demodulation outputs V Xi1 , V Xq1 , V Xi2 , V Xq2 obtained by demodulating the detection voltage V ωβ by the first demodulation unit 113 and the second demodulation unit 114. The first demodulation output calculation unit 130 includes, for example, as shown in FIG. 8, a plurality of HPFs 131 to 134, phase comparison units 135 and 136, and calculation units 137 and 138, and θ ωβObtain the necessary calculation and phase difference information for controlling to 0. HPF is an abbreviation for High Pass Filter, and any high-pass filter such as a DC cut filter is used. The phase comparison units 135 and 136 use, for example, phase comparators and output a signal corresponding to the phase difference in the two input signals. The results of various calculations by the first demodulation output calculation unit 130 are output to, for example, the control circuit 150.

[0049] The second demodulation output calculation unit 140 performs a calculation for controlling θ YP to 0 based on the demodulation outputs V Yi1 , V Yq1 , V Yi2 , V Yq2 obtained by demodulating the detection voltage V ωβ by the first demodulation unit 123 and the second demodulation unit 124. The second demodulation output calculation unit 140 includes, for example, a plurality of HPFs 141 to 144, phase comparison units 145 and 146, and calculation units 147 and 148, and obtains the necessary calculation and phase difference information for controlling θ ωβ to 0. The results of various calculations by the second demodulation output calculation unit 140 are output to, for example, the control circuit 150. The HPFs 141 to 144, the phase comparison units 145 and 146, and the calculation units 147 and 148 have the same configurations as the HPFs 131 to 134, the phase comparison unit 135, 136, and the calculation units 137 and 138, respectively.

[0050] Note that the demodulation outputs V Xi1 , V Xq1 , V Xi2 , V Xq2 , V Yi1 , V Yq1 , V Yi2 , V Yq2 as well as the calculations and the like in the demodulation output calculation units 130 and 140 will be described later.

[0051] Based on the calculation results in the demodulation output calculation units 130 and 140, the control circuit 150 calculates the voltage V ωβ as a control signal for making θ Q equal to 0, and V Q+ and V Q-Outputs to the sensor unit and controls one of V Q+ and V Q- . The control circuit 150 is, for example, a PI circuit.

[0052] The above is the basic configuration of the control unit 10. The control unit 10 executes the control of Δω β = 0 by the PLL circuits 110 and 120, the AGC circuits 111 and 121, and the PI circuits 112 and 122, and executes the control of θ ωβ = 0 by the second demodulation units 114 and 124, the demodulation output calculation units 130 and 140, and the control circuit 150. That is, the control unit 10 has an independent configuration of a control loop of Δω β = 0 and a control loop of θ ωβ = 0. In mode matching, while executing the control of Δω β = 0 in parallel, it is possible to execute the control of θ ωβ = 0 independently of the control of Δω β = 0. As a result, even if the gyro sensor 1 has θ ω ≠ 0 and Δω ≠ 0 in the initial state, two independent controls of the control of θ ωβ = 0 and the control of Δω β = 0 work properly, and a configuration enabling mode matching control of Δω β = 0 is achieved.

[0053] Note that the control unit 10 may have a DAC (not shown in the figure as required), which is a circuit that outputs various voltages V XT , V XD , V YT , V YD , V Q+ or V Q- to the sensor unit. DAC is an abbreviation for Digital to Analog Converter. The control unit 10 may have an ADC (not shown in the figure as required), which is a circuit that detects detection voltages V XP , V YP . ADC is an abbreviation for Analog to Digital Converter.

[0054] 〔Calculation in the demodulation unit〕 Next, the arithmetic processing in the demodulation units 114 and 124 and the demodulation output arithmetic units 130 and 140 will be described. Here, the case of n = 2 in the wine glass mode will be described as a representative example, and the description of the higher-order cases of n = 3 or more will be omitted because they are basically the same.

[0055] When the resonator 2 is resonantly driven in both the first and second vibration modes of the resonance mode of n = 2, for example, as shown in FIG. 9, it vibrates along two orthogonal vibration axes x and y. Let the vibration amplitude and mode frequency on the vibration axis x be A and ω1, respectively, and the vibration amplitude and mode frequency on the vibration axis y be B and ω2, respectively, and let the angle formed by the vibration axis x and the electrode axis X be θ. ω At this time, the vibration amplitudes of the vibration axes x and y at time t are represented by the following equations (3) and (4).

[0056] x = A sin(ω1t + φ1) ··· (3) y = B sin(ω2t + φ2) ··· (4)

[0057] φ1 in equation (3) and φ2 in equation (4) are the phases with respect to the external forces applied from each direction. Let the respective components of the vibration with amplitude A on the electrode axes X and Y be a X , a Y , and let the respective components of the vibration with amplitude B on the electrode axes X and Y be b X , b Y . Then, θ ω , which is the deviation angle between the vibration axis x and the electrode axis X, is represented by the following equation (5) from the orthogonality of the vibration axes x and y.

[0058]

Equation

[0059]

Equation

[0060] X = a X sin(ω1t + φ1) + b X sin(ω2t + φ2) ··· (7) Y = a Y sin(ω1t + φ1) + b Y sin(ω2t + φ2) ··· (8) In equations (7) and (8), each component a X , b X , a Y , b Y is, in the example shown in FIG. 9, a X = Acosθ ω , b X = -Bsinθ ω , a Y = Asinθ ω , b Y = Bcosθ ω . Also, assuming the conversion coefficients from the amplitude to the voltage according to the detection method are ξ X , ξ Y , the voltages V XP , V YP at the detection electrodes on the electrode axes X and Y respectively are expressed by the following equations (9) and (10).

[0061] V XP = ξ X {a X sin(ω1t + φ1) + b X sin(ω2t + φ2)} ··· (9) V YP = ξ Y {a Y sin(ω1t + φ1) + b Y sin(ω2t + φ2)} ··· (10) The first demodulation unit 113 performs calculations of the demodulation outputs V XP , V Xi1 , V Xq1 for the external forces on the vibration axes x and y based on the voltage V Xi1 , V Xq1respectively, are the demodulation outputs in phase with the drive signal of the resonance frequency ω1 and in quadrature with the drive signal, which are calculated based on the detection voltage V XP . The demodulation output V Xi1 is calculated by multiplying the voltage V XP by sinω1t and then passing it through a low-pass filter to eliminate the second harmonic and sum frequency terms as expressed by the following equation (12).

[0062]

Equation

[0063]

Equation

[0064] |f(t)| in equation (12) LPF means the operation of eliminating the second harmonic and sum frequency terms passing through the above-mentioned low-pass filter. The same applies to equations (14), (16), and (18) hereinafter.

[0065] The demodulation output V Xq1 is calculated by multiplying the voltage V XP by cosω1t and then passing it through a low-pass filter to eliminate unnecessary terms as expressed by the following equation (14).

[0066]

Equation

[0067]

Equation

[0068] V XP sin(ω2t + Δφ) = ξ X {a X sin(ω1t + φ1) + b X sin(ω2t + φ2)}sin(ω2t + Δφ) ··· (15)

[0069]

Equation

[0070] V XP cos(ω2t + Δφ) = ξ X {a X sin(ω1t + φ1) + b X sin(ω2t + φ2)}cos(ω2t + Δφ) ··· (17)

[0071]

Equation

[0072] Hereinafter, for simplicity of explanation, the demodulation outputs V Xi1 V Xq1 calculated by the first demodulation unit 113 may be respectively referred to as "the first demodulation output", and the demodulation outputs V Yi2 V Yq2 calculated by the first demodulation unit 123 may be respectively referred to as "the second demodulation output". Also, the demodulation outputs V Xi2 V Xq2 calculated by the second demodulation unit 114 may be referred to as "the third demodulation output", and the demodulation outputs V Yi1 V Yq1may be respectively referred to as the "fourth demodulation output". The control unit 10 is configured such that the first demodulation output calculation unit 130 performs calculations based on the first demodulation output and the third demodulation output, and the second demodulation output calculation unit 140 performs calculations based on the second demodulation output and the fourth demodulation output.

[0073] Here, the angle θ formed by the vibration axes x and y and the electrode axes X and Y ω can be calculated by the following equation (19) or (20).

[0074]

Equation

[0075]

Equation

[0076] C in equations (19) and (20) X , C Y are collectively denoted as C k Then, C k is represented by the following equation (21).

[0077] C k =|ξ k 2 a k b k | (k = X, Y) ··· (21) Based on the demodulation outputs calculated by the demodulation units 113, 114, 123, and 124, the control unit 10 controls one of the control voltages V ω , V Q+ , V Q- applied from the control circuit 150 to the sensor unit while making |θ ω | = 0 represented by equation (19) or (20). |θ Y | = 0 means |ξ Y | = 0 or |ξ X b XThis is the case where |=0 is satisfied. The first demodulation output calculation unit 130, for example, as shown in FIG. 8, in the calculation unit 137, the demodulation outputs V at φ1 = φ2 = Δφ = 0 Xi1 , V Xq1 are each squared and then added together by performing a sum-of-squares operation to calculate the value of |ξ X b X |. The second demodulation output calculation unit 140, for example, in the calculation unit 147, the demodulation outputs V at φ1 = φ2 = Δφ = 0 Yi2 , V Yq2 are each squared and then added together by performing a sum-of-squares operation to calculate the value of |ξ Y b Y |. These calculation results are output to, for example, the control circuit 150, and are used for feedback control such that |ξ Y a Y | = 0 or |ξ X b X | = 0, that is, |θ ω | = 0.

[0078] Also, in the feedback control where |θ ω | = 0, for example, when aligning the vibration axes x and y with the electrode axes X and Y, both control voltages V Q+ , V Q- are applied, but one of them is controlled according to the direction in which the vibration axes x and y are to be rotated. Specifically, when rotating the vibration axes x and y counterclockwise, the control voltage of V Q+ is controlled, and when rotating clockwise, the control voltage of V Q- is controlled. For example, as shown in FIG. 9, when the vibration axes x and y are misaligned from the electrode axes X and Y by an angle θ ω counterclockwise, the control circuit 150 controls the control voltage V Q+ , V Q- of the vibration axes x and y of the vibrator 2 that rotates clockwise among them. Q-

[0079] The demodulation output calculation units 130 and 140 are |θ ω ​In the feedback control of |=0, the directions for rotating the vibration axes x and y are calculated. Specifically, the first demodulation output calculation unit 130 demodulates the output V after passing through the HPF131 Xq1 and the demodulated output V after passing through the HPF133 Xq2 Based on these, the phase comparison unit 135 calculates Δφ Xq . Also, the first demodulation output calculation unit 130 demodulates the output V after passing through the HPF132 Xi1 and the demodulated output V after passing through the HPF134 Xi2 Based on these, the phase comparison unit 136 calculates Δφ Xi . Similarly, the second demodulation output calculation unit 140 demodulates the output V after passing through the HPF144 Yq1 and the demodulated output V after passing through the HPF142 Yq2 Based on these, the phase comparison unit 146 calculates Δφ Yq . Also, the second demodulation output calculation unit 140 demodulates the output V after passing through the HPF143 Yi1 and the demodulated output V after passing through the HPF141 Yi2 Based on these, the phase comparison unit 145 calculates Δφ Yi .

[0080] Then, as shown in FIG. 11 for example, the control circuit 150 determines whether the output waveforms of the demodulated outputs V Xi , V Xq and the output waveforms of the demodulated outputs V Yi , V Yq are in-phase or out-of-phase based on the calculated phase difference. The control circuit 150 determines the polarity of θ ω , that is, whether the vibration axes x and y are shifted clockwise or counterclockwise with respect to the electrode axes X and Y. Note that in FIG. 11, the polarity “+” of θ ω means that the vibration axis is shifted counterclockwise with respect to the electrode axis, and the polarity “-” of θ ω means that the vibration axis is shifted clockwise with respect to the electrode axis. The control circuit 150 determines one of the control target outputs of the control voltages V ω according to the polarity of θ Q+ , V Q- , and determines the control target as one side, and V Q+ , V Q-While outputting, control is performed on one of the controlled objects that has been determined.

[0081] In this way, when the sensor unit is in the initial state and θ ωα ≠0 and Δω α ≠0, based on the demodulation outputs from the second demodulation units 114 and 124, Δω β =0 control independent of θ ωβ =0 feedback control can be executed.

[0082] According to this embodiment, the gyro sensor 1 has two independent PLL circuits 110 and 120 for maintaining the resonator 2 by resonance driving in the first vibration mode and the second vibration mode, and includes first demodulation units 113 and 123 and second demodulation units 114 and 124. The first demodulation units 113 and 123 respectively calculate demodulation outputs V Xi1 , V Xq1 based on the detection voltage of the first vibration mode of the resonance frequency ω1 and the first drive signal, and demodulation outputs V Yi2 , V Xq2 based on the detection voltage of the second vibration mode of the resonance frequency ω2 and the second drive signal. The second demodulation units 114 and 124 respectively calculate demodulation outputs V Xi2 , V Xq2 based on the detection voltage of the first vibration mode and the second drive signal, and demodulation outputs V Yi1 , V Xq1 based on the detection voltage of the second vibration mode and the first drive signal. Then, the gyro sensor 1 can calculate control voltages V ωβ for controlling |θ Q+ | = 0 by the demodulation output calculation units 130 and 140 based on these demodulation outputs, and feedback them to the sensor unit by the control circuit 150. Therefore, the gyro sensor 1 can perform feedback control of |θ Q- | = 0 independently of the mode matching control of Δω β = 0 by having two PLL circuits 110 and 120, first demodulation units 113 and 123, and second demodulation units 114 and 124. Thus, the gyro sensor 1 has θ ωβ in the initial state. ωEven when using a sensor unit where ≠0 and Δω≠0, it is possible to perform control to constantly maintain mode matching without subjecting the sensor unit to special processing or the like.

[0083] (Modification of the First Embodiment) The gyro sensor 1, for example, as shown in FIG. 12, Δω β The control of mode matching where =0 may be executed by a PI circuit 151 instead of the two PI circuits 112 and 122.

[0084] In this case, the control unit 10 does not have the PI circuits 112 and 122. For example, it outputs one of the applied voltages V XT , V YT to the sensor unit. The PI circuit 151, for example, receives signals corresponding to the calculation results from the demodulation output calculation units 130 and 140, and based on the amplitude information and phase information obtained by the calculation, outputs a voltage to change one of the mode frequencies ω1 and ω2 so that Δω β =0. The PI circuit 151 outputs one of the voltages V Y b Y |=0 or |ξ X a X |=0 to the sensor unit so that. When the mode frequency ω1>ω2, the PI circuit 151 outputs the voltage V XT , V YT to make |ξ Y b Y |=0, and when the mode frequency ω1<ω2, it outputs the voltage V YT to make |ξ X a X |=0, and performs mode matching control where Δω XT =0. β

[0085] Also according to this modification example, the gyro sensor 1 can obtain the same effects as those of the first embodiment above.

[0086] (Second Embodiment) The gyro sensor 1 of the second embodiment will be described with reference to FIGS. 13 and 14. In FIG. 14, for ease of viewing, the feedback from the first demodulation unit 113 to the PLL circuit 110 and the AGC circuit 111, and the feedback from the first demodulation unit 123 to the PLL circuit 120 and the AGC circuit 121 are omitted.

[0087] The gyro sensor 1 of this embodiment is different from the first embodiment in that the configuration of the control unit 10 is changed, as shown in FIG. 13 for example. In this embodiment, this difference will be mainly described.

[0088] In this embodiment, the control unit 10 further includes an oscillation circuit 160, as shown in FIG. 13 for example, and the signal from the oscillation circuit 160 is input to the demodulation output calculation units 130 and 140. The oscillation circuit 160 calculates the difference Δω between the two resonance frequencies ω1 and ω2 based on the drive signals output from the two PLL circuits 110 and 120, for example. Then, the oscillation circuit 160 outputs a frequency signal with a frequency of Δω to the demodulation output calculation units 130 and 140 respectively.

[0089] In this embodiment, the first demodulation output calculation unit 130 includes a plurality of third demodulation units 139 that respectively demodulate the demodulation outputs from the demodulation units 113 and 114, and phase comparison units 135 and 136, as shown in FIG. 14 for example. In FIG. 14, for ease of viewing, only one signal input from the oscillation circuit 160 to one of the plurality of third demodulation units 139 and 149 is shown, and the signal inputs to the other third demodulation units are omitted.

[0090] The plurality of third demodulation units 139 are based on the demodulation outputs V Xi1 , V Xq1 , V Xi2 , V Xq2 and the frequency signal of Δω input from the oscillation circuit 160, and calculate the amplitude information |ξ X a X |, |ξ X b X | and the phase information φ Xi1 , φ Xq1 , φ Xi2 , φ Xq2Perform calculations. The phase comparison unit 135 calculates, for example, the phase difference Δφ based on the phase information φ, φ from the third demodulation unit 139. Xi1 , φ Xi2 The phase comparison unit 136 calculates, for example, the phase difference Δφ based on the phase information φ, φ from the third demodulation unit 139. Xi , φ Xq1 , φ Xq2 The phase comparison unit 136 calculates, for example, the phase difference Δφ based on the phase information φ, φ from the third demodulation unit 139. Xq .

[0091] In this embodiment, the demodulated output calculation unit 140 includes a plurality of third demodulation units 149 that respectively demodulate the demodulated outputs from the demodulation units 123 and 124, and phase comparison units 145 and 146.

[0092] Based on the demodulated outputs V, V, V, V, V, V and the frequency signal of Δω input from the oscillation circuit 160, the plurality of third demodulation units 149 calculate the amplitude information |ξa|, |ξb| and the phase information φ, φ, φ, φ. The phase comparison unit 145 calculates, for example, the phase difference Δφ based on the phase information φ, φ from the third demodulation unit 149. The phase comparison unit 146 calculates, for example, the phase difference Δφ based on the phase information φ, φ from the third demodulation unit 149. Yi1 , V Yq1 , V Yi2 , V Yq2 Based on the demodulated outputs V, V, V, V, V, V and the frequency signal of Δω input from the oscillation circuit 160, the plurality of third demodulation units 149 calculate the amplitude information |ξa|, |ξb| and the phase information φ, φ, φ, φ. The phase comparison unit 145 calculates, for example, the phase difference Δφ based on the phase information φ, φ from the third demodulation unit 149. The phase comparison unit 146 calculates, for example, the phase difference Δφ based on the phase information φ, φ from the third demodulation unit 149. Y a Y |, |ξ Y b Y | and the phase information φ, φ, φ, φ. The phase comparison unit 145 calculates, for example, the phase difference Δφ based on the phase information φ, φ from the third demodulation unit 149. The phase comparison unit 146 calculates, for example, the phase difference Δφ based on the phase information φ, φ from the third demodulation unit 149. Yi1 , φ Yq1 , φ Yi2 , φ Yq2 Based on the demodulated outputs V, V, V, V, V, V and the frequency signal of Δω input from the oscillation circuit 160, the plurality of third demodulation units 149 calculate the amplitude information |ξa|, |ξb| and the phase information φ, φ, φ, φ. The phase comparison unit 145 calculates, for example, the phase difference Δφ based on the phase information φ, φ from the third demodulation unit 149. The phase comparison unit 146 calculates, for example, the phase difference Δφ based on the phase information φ, φ from the third demodulation unit 149. Yi1 , φ Yi2 The phase comparison unit 145 calculates, for example, the phase difference Δφ based on the phase information φ, φ from the third demodulation unit 149. Yi The phase comparison unit 146 calculates, for example, the phase difference Δφ based on the phase information φ, φ from the third demodulation unit 149. Yq1 , φ Yq2 The phase comparison unit 146 calculates, for example, the phase difference Δφ based on the phase information φ, φ from the third demodulation unit 149. Yq .

[0093] The amplitude information and phase information obtained by the calculations in the demodulated output calculation units 130 and 140 are output to the control circuit 150 and used for the feedback control of θ = 0 similar to the first embodiment. ωβ .

[0094] Also according to this embodiment, the gyro sensor 1 that obtains the same effect as the first embodiment is obtained.

[0095] (Other embodiments) Although the present disclosure has been described in accordance with the embodiments, it is understood that the present disclosure is not limited to the embodiments or structures. The present disclosure also includes various modifications and variations within the equivalent scope. In addition, various combinations and forms, and other combinations and forms including only one of these elements, more, or less, also fall within the scope and spirit of the present disclosure.

[0096] In the above embodiment, an example of the structure in which the first electrode portion 51 is formed by etching a base material such as silicon and includes a plurality of opposing portions that are separated from each other and oppose the rim 23, and an electrode film (not shown) that covers the upper surface of the opposing portions has been described, but the present disclosure is not limited thereto. For example, as shown in FIG. 15, in the sensor element, one substantially hemispherical recess 53 may be formed in the upper substrate 5, and the plurality of first electrode portions 51 may be constituted only by an electrode film that covers the surface of the recess 53. In this case, for example, the second electrode portion 52 may be constituted only by an electrode film that covers the surface of the upper substrate 5, similarly to the first electrode portion 51. Further, the second electrode portion 52 may be electrically connected to a portion of the recess 53 that is connected to the vibrator 2 while being electrically independent from the plurality of first electrode portions 51, as long as a voltage can be applied to the vibrator 2. For example, in the sensor element, a through electrode (not shown) extending along the thickness direction of the mounting substrate 3 may be formed in a portion of the recess 53 to which the vibrator 2 is connected, and the sensor element may be constituted only by an electrode film connected to the through electrode. Further, in the case where the mounting surface of the mounting portion 22 of the vibrator 2 protrudes more than the rim 23, the mounting substrate 3 may not have the recess 53, and the first electrode portion 51 and the second electrode portion 52 may be constituted only by an electrode film that covers the surface of the upper substrate 5. Thus, the configurations of the first electrode portion 51 and the second electrode portion 52 in the sensor element may be appropriately changed or may be other known configurations. Note that in FIG. 15, a part of the vibrator 2 is omitted and a cross section is shown for easy understanding of the configurations of the electrode portions 51 and 52.

[0097] In addition, as a representative example, the sensor element has been described with a configuration in which the vibrator 2 has a substantially hemispherical shape or a substantially disk shape, and a plurality of first electrode portions 51 are arranged so as to surround it. However, the present invention is not limited to such forms. For example, if the gyro sensor 1 is in a form in which the sensor element can be regarded as a two-degree-of-freedom vibrating body shown in FIG. 5, since the control unit 10 can control the constant mode match at all times, the forms and arrangements of the vibrator 2 and the electrode portions 51 and 52 may be other known ones.

[0098] The control unit 10 and its method described in the present disclosure may be realized by a dedicated computer provided by configuring a processor and a memory programmed to execute one or more functions embodied by a computer program. Alternatively, the control unit 10 and its method described in the present disclosure may be realized by a dedicated computer provided by configuring a processor with one or more dedicated hardware logic circuits. Or, the control unit 10 and its method described in the present disclosure may be realized by one or more dedicated computers configured by a combination of a processor and a memory programmed to execute one or more functions and a processor configured by one or more hardware logic circuits. Further, the computer program may be stored in a computer-readable non-transitory tangible recording medium as instructions to be executed by a computer.

[0099] In addition, in each of the above embodiments, it goes without saying that the elements constituting the embodiments are not necessarily essential, except in cases where it is explicitly stated that they are essential or in cases where they are considered to be clearly essential in principle. Further, in each of the above embodiments, when numerical values such as the number, numerical value, quantity, range, etc. of the constituent elements of the embodiment are mentioned, they are not limited to that specific number, except in cases where it is explicitly stated that they are essential or in cases where they are clearly limited to a specific number in principle. Also, in each of the above embodiments, when referring to the shape, positional relationship, etc. of the constituent elements, etc., they are not limited to that shape, positional relationship, etc., except in cases where it is explicitly stated or in cases where they are clearly limited to a specific shape, positional relationship, etc. in principle.

Description of Reference Numerals

[0100] 2... oscillator, 3... mounting substrate, 51... first electrode portion, 110... (first) PLL circuit, 120... (second) PLL circuit, 113, 123... first demodulation portion, 114, 124... second demodulation portion, 130... first demodulation output calculation portion, 131 - 134... HPF (high-pass filter), 135, 136... phase comparison portion, 137, 138... calculation portion, 140... second demodulation output calculation portion, 141 - 144... HPF (high-pass filter), 145, 146... phase comparison portion, 147, 148... calculation portion, 139, 149... third demodulation portion, 150... control circuit, 151... PI circuit, 160... oscillation circuit, V XP … first detection voltage, V YP … second detection voltage, V Q+ 、V Q- 、V XT 、V YT … control signal, V Xi1 、V Xq1 … first demodulation output, V Yi2 、V Yq2 … second demodulation output, V Xi2 、V Xq2 … third demodulation output, V Yi1 、V Yq1 … fourth demodulation output, x, y... vibration axes, X, Y... electrode axes, ω1... resonance frequency of the first vibration mode, ω2... resonance frequency of the second vibration mode, Δω... difference in resonance frequencies

Claims

1. An oscillator (2) having a first vibration mode and a second vibration mode with different resonance frequencies, A mounting substrate (3) having a plurality of electrodes (51) facing the oscillator, A first PLL circuit (110) for controlling the frequency of a drive signal for vibrating the oscillator in the first vibration mode, A second PLL circuit (120) for controlling the frequency of a drive signal for vibrating the oscillator in the second vibration mode, A radial direction with a virtual straight line passing through the center of the region surrounded by the plurality of electrodes and along the thickness direction of the mounting substrate as an axis, and two directions along the drive electrodes used for driving the first vibration mode and the second vibration mode among the plurality of electrodes are defined as electrode axes (X, Y), Two directions along the direction along the radial direction and along the vibration directions of the first vibration mode and the second vibration mode are defined as vibration axes (x, y), The first detection voltage (V ＸＰ ), from the electrode that detects the vibration of the first vibration mode among the plurality of the electrodes, and the first drive signal of the frequency (ω １ ) that resonantly drives the first vibration mode output from the first PLL circuit, based on which a first demodulation output (V Ｘｉ１ , V Ｘｑ１ ), and the second detection voltage (V ＹＰ ), from the electrode that detects the vibration of the second vibration mode among the plurality of the electrodes, and the second drive signal of the frequency (ω ２ ) that resonantly drives the second vibration mode output from the second PLL circuit, based on which a first demodulation unit (113, 123) that calculates a second demodulation output (V Ｙｉ２ , V Ｙｑ２ ) A second demodulation unit (114, 124) that calculates a third demodulation output (V Ｘｉ２ , V Ｘｑ２ ) based on the first detection voltage and the second drive signal, and a fourth demodulation output (V Ｙｉ１ , V Ｙｑ１ ) based on the second detection voltage and the first drive signal; A first demodulation output calculation unit (130) that calculates the amplitude and phase of the first vibration mode based on the first demodulation output and the third demodulation output, A second demodulation output calculation unit (140) that calculates the amplitude and phase of the second vibration mode based on the second demodulation output and the fourth demodulation output, A control circuit (150) that outputs a control signal (V Ｑ＋ , V Ｑ－ ) for matching the vibration axis and the electrode axis based on an input signal regarding the amplitude and the phase from the first demodulation output calculation unit or the second demodulation output calculation unit. A gyro sensor comprising the control circuit (150).

2. The first demodulation output calculation unit includes a high-pass filter (131 to 134) that cuts a part of the first demodulation output and the third demodulation output, and calculates the sum of squares by squaring and adding the first demodulation output and the third demodulation output after passing through the high-pass filter, and calculates the amplitude of the first vibration mode. An arithmetic unit (137, 138), and a phase comparison unit (135, 136) that calculates the phase of the first vibration mode based on the first demodulation output and the third demodulation output after passing through the high-pass filter. The second demodulation output calculation unit includes a high-pass filter (141 to 144) that cuts a part of the second demodulation output and the fourth demodulation output, and calculates the sum of squares by squaring and adding the second demodulation output and the fourth demodulation output after passing through the high-pass filter, and calculates the amplitude of the second vibration mode. An arithmetic unit (147, 148), and a phase comparison unit (145, 146) that calculates the phase of the second vibration mode based on the second demodulation output and the fourth demodulation output after passing through the high-pass filter. The gyro sensor according to claim 1.

3. The apparatus further includes an oscillation circuit (160) that outputs a frequency signal of a difference (Δω) between resonance frequencies of the first vibration mode and the second vibration mode based on the first drive signal and the second drive signal. The first demodulation output calculation unit includes a third demodulation unit (139) that performs demodulation processing using the frequency signal from the oscillation circuit and calculates the amplitude and phase of the first vibration mode. The gyro sensor according to claim 1, wherein the second demodulation output calculation unit includes a third demodulation unit (149) that performs demodulation processing using the frequency signal from the oscillation circuit and calculates the amplitude and phase of the second vibration mode.

4. Based on the input signal from the first demodulation output calculation unit or the second demodulation output calculation unit, a control signal (V ＸＴ , V ＹＴ ) for making the difference between the resonance frequency of the first vibration mode and the resonance frequency of the second vibration mode zero, and further having a PI circuit (151) that outputs the control signal, the gyro sensor according to claim 2.

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