JP2014016356A - Method for manufacturing angular velocity detection device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a technology capable of determining disconnection of a signal line connected to a vibrator in an angular velocity detection device which includes the WT type vibrator.SOLUTION: The angular velocity detection device includes: a vibrator; a drive circuit that drives the vibrator so as to allow the vibrator to perform excitation vibration; two signal lines that are electrically connected to the vibrator so as to take out two first detection signals having opposite phases from the vibrator, and a detection circuit; and a detection circuit that differentially amplifies the two first detection signals from the two signal lines so as to generate a second detection signal based on the two first detection signals, respectively extracts an angular velocity component based on a Coriolis force and a self- vibration component based on the excitation vibration from the generated second detection signal, and outputs the extracted self-vibration component to a malfunction determination circuit at the subsequent stage. Balance tuning for setting a magnitude of the self-vibration component which is output from the detection circuit by shifting it from zero (0) is applied to the vibrator.

Description

  The present invention relates to an angular velocity detection device and a manufacturing method thereof.

  The detection signal from the vibrator in the angular velocity detection device includes a self-vibration component based on the excitation vibration of the vibrator. Patent document 1 is disclosing determining the failure of an angular velocity detection apparatus based on a leak signal (self-vibration component). According to FIG. 5 of Patent Document 1, when the output signal of the integrating circuit whose level changes according to the amplitude of the leakage signal is in the range of V2 or more and V1 or less, the failure determination circuit outputs a signal indicating that there is no abnormality. When it is out of the range, a signal indicating that the failure determination circuit is abnormal is output.

  Paragraphs (0019) to (0026) of Patent Document 2 disclose that the balance of the mass of the drive vibrating piece is adjusted to reduce the difference in magnitude between the two detection signals.

JP 2000-171257 A JP 2005-37235 A

  Patent Document 1 discloses an invention in which failure determination is performed based on a leakage signal (self-vibration component). However, two excitation vibrating pieces extending in the + Y-axis direction from the base and two extending in the −Y-axis direction from the base are disclosed. An H-type vibrating piece having a detecting vibrating piece is assumed. This H-shaped vibrating piece has a structure in which the vibrating pieces for detection are separated from each other when the vibrating pieces for excitation are close to each other, and the vibrating pieces for detection are brought close to each other when the vibrating pieces for excitation are separated from each other. Balance tuning that sets the vibration component to 0 cannot be performed.

  Patent Document 2 discloses balance adjustment for reducing the difference between the magnitudes of two detection signals. However, even if a leak signal (self-vibration component) is close to 0 and there is a failure such as disconnection, an output signal is disclosed. The level does not change and disconnection cannot be determined.

  The present invention can be realized as the following forms or application examples so as to solve the above-described problems.

  [Application Example 1] The angular velocity detection device takes out a vibrator, a drive circuit that drives the vibrator so that the vibrator vibrates, and two first detection signals having opposite phases from the vibrator. In this way, two signal lines electrically connected to the vibrator and a second detection based on the two first detection signals by differentially amplifying the two first detection signals from the two signal lines A signal is generated, and an angular velocity component based on Coriolis force and a self-vibration component based on the excitation vibration are extracted from the generated second detection signal, respectively, and the extracted self-vibration component is used as a failure in the subsequent stage. And a detection circuit for outputting to the determination circuit. And the balance tuning which shifts and sets the magnitude | size of the said self-oscillation component output from the said detection circuit from 0 is given to the said vibrator | oscillator.

  Application Example 2 The angular velocity detection device extracts a vibrator, a drive circuit that drives the vibrator so that the vibrator vibrates, and two first detection signals having opposite phases from the vibrator. In this way, two signal lines electrically connected to the vibrator and a second detection based on the two first detection signals by differentially amplifying the two first detection signals from the two signal lines A detection circuit for generating an angular velocity component based on Coriolis force and a self-vibration component based on the excitation vibration from the generated second detection signal; and a detection circuit for the extracted self-vibration component A failure determination circuit that determines that the vibrator has failed when the size decreases. And the balance tuning which shifts and sets the magnitude | size of the said self-oscillation component output from the said detection circuit from 0 is given to the said vibrator | oscillator.

Application Example 3 The vibrator, the driving circuit that drives the vibrator so that the vibrator vibrates, and the vibration so that two first detection signals having opposite phases are extracted from the vibrator. Two signal lines electrically connected to the child and the two first detection signals from the two signal lines are differentially amplified to generate a second detection signal based on the two first detection signals. Then, an angular velocity component based on the Coriolis force and a self-vibration component based on the excitation vibration are extracted from the generated second detection signal, and the extracted self-vibration component is output to the subsequent failure determination circuit. And a detection circuit that includes a balance tuning step for setting the magnitude of the self-vibration component output from the detection circuit by shifting from zero.
Further, in another aspect, the detection vibration piece extending from the detection base, and the drive vibration piece disposed on both sides with respect to the detection vibration piece, the drive vibration piece of the The vibration direction due to the drive vibration and the vibration direction due to the Coriolis force of the detection vibration piece are in a substantially coplanar relationship, and includes a component based on the Coriolis force and a self-vibration component based on the drive vibration A detection circuit that extracts the self-vibration component from the signal, and a failure determination circuit to which a signal from the detection circuit is input, The method includes a step of balance tuning the self-vibration component output from the detection circuit to a value different from zero.
In another aspect, the balance tuning includes a step of forming a film on the drive vibrating piece and removing a part of the film.
In another aspect, the failure determination circuit determines that the vibrator has failed when the magnitude of a signal from the detection circuit input to the failure determination circuit decreases.
In another aspect, the magnitude of the signal from the detection circuit input to the failure determination circuit is at least 1 and less than 2 times the lower limit reference value defined by the failure determination circuit as a normal value. It is characterized by.
In another aspect, the vibrator includes a connecting arm extending from the detection base in a direction intersecting with an extending direction of the detection vibrating piece, and a driving arm disposed on the connecting arm. A base portion and the drive vibration piece extending from the drive base portion are provided.

The circuit block diagram which shows an example of the angular velocity detection apparatus which concerns on this Embodiment. Schematic which shows an example of the vibrator | oscillator which concerns on this Embodiment. Schematic which shows an example of the vibrator | oscillator which concerns on this Embodiment. The timing chart at the time of paying attention to the angular velocity component of a detection signal. The timing chart at the time of paying attention to the self-vibration component of a detection signal.

  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.

  1. Angular Velocity Detection Device FIG. 1 is a circuit block diagram showing an example of an angular velocity detection device according to the present embodiment.

  An angular velocity detection device 1 according to the present embodiment includes an angular velocity detection circuit 5 and a vibrator 10.

  2. The vibrator 10 is excited and oscillated based on the drive signals input from the drive terminals 13 and 14, and a Coriolis force is generated when the rotational motion is activated in the excited vibration state. The vibrator 10 outputs a detection signal including an angular velocity component based on the Coriolis force and an excitation vibration component based on the excitation vibration. Here, the excitation vibration component and the angular velocity component based on the Coriolis force are 90 ° out of phase.

  Next, an example of the vibrator 10 formed from a thin plate of a piezoelectric material such as quartz will be described with reference to FIGS. In the vibrator 10, the drive vibration arm 11 (drive vibration piece in a broad sense) extends from the drive base 44 in the + Y axis direction and the −Y axis direction of the crystal. The drive base 44 is connected to the detection base 49 via a connecting arm 45 extending in the X-axis direction of the crystal. The detection vibration arm 12 (detection vibration piece in a broad sense) extends from the detection base 49 in the + Y axis direction and the −Y axis direction.

  When a drive signal composed of alternating voltage / alternating current is applied between the drive electrode 41 on the side surface of the drive vibration arm 11 and the drive electrode 42 on the top surface of the drive vibration arm 11, the drive vibration arm 11 is Bend and vibrate as shown by arrow B. Here, as shown in FIG. 3, when the vibrator 10 rotates about the Z axis of the crystal as a rotation axis, the drive vibrating arm 11 moves in a direction perpendicular to both the direction of the bending vibration indicated by the arrow B and the Z axis. Get the power of Coriolis. As a result, the connecting arm 45 vibrates as indicated by an arrow C. Then, the detection vibrating arm 12 performs bending vibration like the arrow D with the connecting arm 45 in conjunction with the vibration of the connecting arm 45 (arrow C).

  The vibration of the drive vibration arm 11 is transmitted through the drive base 44, the connecting arm 45, and the detection base 49, and causes the detection vibration arm 12 to generate a leakage vibration (arrow E). This leakage vibration is a bending vibration similar to the vibration based on the Coriolis force (arrow D), but the phase of the leakage vibration and the vibration based on the Coriolis force are shifted by 90 °.

  An alternating voltage / alternating current is generated between the detection electrodes 47a and 47b on the side surface of the detection vibrating arm 12 and the detection electrodes 46a and 46b on the upper surface due to the inverse piezoelectric effect generated based on these bending vibrations. Occur. The detection electrodes 47a and 47b on the side surface of the detection vibrating arm 12 are connected to the detection terminals 15 and 16, respectively, and the detection electrodes 46a and 46b on the upper surface are both connected to the ground terminal 17. As described above, the detection signals output to the detection terminals 15 and 16 include an angular velocity component based on Coriolis force and a leakage component (self-vibration component) based on excitation vibration of drive vibration.

  2 and 3, in order to improve the balance of the vibrator, the detection base 49 is arranged in the center, and the detection vibrating arm 12 is extended from the detection base 49 in both the + Y axis and the −Y axis. I am letting. Further, the connecting arm 45 extends from the detection base 49 in both the + X-axis and −X-axis directions, and the drive vibrating arm 11 extends from each of the connecting arms in both the + Y-axis and −Y-axis directions.

  Further, the distal end of the drive vibrating arm 11 is formed into a wide portion 43, and a weight is attached to increase the Coriolis force. Also, due to the weight effect, a desired resonance frequency can be obtained with a short vibrating arm. For the same reason, the tip end of the detection vibrating arm 12 is formed into a wide portion 48 and further a weight is attached.

  The vibrator 10 is not limited to the above-described configuration, and may be any vibrator that outputs a detection signal including an angular velocity component based on Coriolis force and a leakage component based on excitation vibration. For example, it may be configured to serve as both the drive vibration arm and the detection vibration arm, or may be configured such that a piezoelectric film is formed on the drive vibration arm and the detection vibration arm.

3. Angular Velocity Detection Circuit The angular velocity detection circuit 5 includes a drive circuit 20 and a detection circuit 30. The drive circuit 20 and the detection circuit 30 can be configured on the same substrate. The detection vibrating arm 12 is provided with detection terminals 15 and 16 and a ground terminal 17, and the detection terminals 15 and 16 are connected to a detection circuit 30.
The detection terminals 15 and 16 are configured to output detection signals having opposite phases to each other.

  4A to 4G are timing charts when attention is paid to the angular velocity component of the detection signal at each point (A) to (G) in the circuit block diagram shown in FIG. 5 (A) to 5 (G) are timing charts when attention is paid to the self-vibration component of the detection signal at each point (A) to (G) in the circuit block diagram shown in FIG. The horizontal axis represents time, and the vertical axis represents voltage.

  The drive circuit 20 outputs a drive signal to drive the vibrator 10 and receives a feedback signal from the vibrator 10. Thereby, the vibrator 10 is excited. The detection circuit 30 receives a detection signal from the vibrator 10 driven by the drive signal, and extracts an angular velocity component based on the Coriolis force from the detection signal.

  The drive circuit 20 in the present embodiment includes a current-voltage converter 21, an AC amplifier 22, an automatic gain control circuit 23, and a comparator 24.

  When the drive vibrating arm 11 vibrates, a current based on the piezoelectric effect is output as a feedback signal from the drive terminal 14 and input to the current-voltage converter 21. The current-voltage converter 21 outputs an AC voltage signal having the same frequency as the vibration frequency of the drive vibrating arm 11 (FIGS. 4A and 5A).

  The AC voltage signal output from the current-voltage converter 21 is input to the AC amplifier 22. The AC amplifier 22 amplifies the input AC voltage signal.

  The AC voltage signal output from the AC amplifier 22 is input to the automatic gain control circuit 23. The automatic gain control circuit 23 controls the gain so that the amplitude of the input AC voltage signal is kept at a constant value, and outputs the AC voltage signal after gain control to the drive terminal 13. The vibrator 10 is driven by the AC voltage signal input to the drive terminal 13.

  The AC voltage signal amplified by the AC amplifier 22 is input to the comparator 24, and a square wave voltage signal (with the center of the amplitude of the AC voltage signal as a reference voltage) that switches the output level according to the comparison result between the AC voltage signal and the reference voltage signal ( FIG. 4B is output to the detection circuit 30.

  The detection circuit 30 in the present embodiment includes a detection signal amplification unit 31, an angular velocity component extraction unit 32, and a self-vibration component extraction unit 33.

  The detection signal amplifying unit 31 includes charge amplifiers 311 and 312, a differential amplifier 313, and an AC amplifier 314.

  The charge amplifiers 311 and 312 are connected to the detection terminals 15 and 16, respectively, and receive detection signals with opposite phases. The signals subjected to charge-voltage conversion by the charge amplifiers 311 and 312 are input to the differential amplifier 313. The differential amplifier 313 performs differential amplification as (output signal of charge amplifier 311) − (output signal of charge amplifier 312). The output signal of the differential amplifier 313 is further amplified by the AC amplifier 314.

  The detection signals output from the detection terminals 15 and 16 include an angular velocity component based on the Coriolis force acting on the vibrator 10 and a self-vibration component (leakage signal component) based on the excitation vibration of the vibrator 10. The angular velocity component extraction unit 32 extracts an angular velocity component from the output signal of the detection signal amplification unit 31. The self-vibration component extraction unit 33 extracts a self-vibration component from the output signal of the detection signal amplification unit 31.

  The angular velocity component extraction unit 32 includes a synchronous detection circuit 321, an AC amplification circuit, an integration circuit 322, a DC amplifier 323, and an output terminal 324. The synchronous detection circuit 321 extracts an angular velocity component by synchronously detecting the output signal of the detection signal amplification unit 31 based on the square wave voltage signal (FIG. 4B) output from the comparator 24. The angular velocity component signal extracted by the synchronous detection circuit 321 is integrated by the integration circuit 322, amplified by the DC amplifier 323, and output from the output terminal 324 as a DC voltage signal.

  The self-vibration component extraction unit 33 according to the present embodiment includes a self-vibration component extraction unit 331, a DC conversion unit 332, and a temperature characteristic correction unit 333. However, in other embodiments, the temperature characteristic correction unit 333 is not an essential component for the self-vibration component extraction unit 33 and may be omitted from the self-vibration component extraction unit 33.

  The self-vibration component extracting unit 331 includes a phase shifter 334 that advances the phase by 90 degrees and a synchronous detection circuit 335. The self-vibration component extracting unit 331 outputs the output signal of the detection signal amplifying unit 31 based on the square wave voltage signal output from the comparator 24 (FIG. 4B) with the phase shifted by 90 degrees by the phase shifter 334. The self-vibration component is extracted by synchronous detection.

  The DC conversion unit 332 includes an integration circuit 336 that functions as an integration unit that integrates the output signal of the self-vibration component extraction unit 331, and converts the output signal of the self-vibration component extraction unit 331 into a DC voltage signal. Further, an AC amplifier 343 is provided before the integrating circuit 336, and a DC amplifier 339 is provided after the integrating circuit 336.

  The operation of these circuits will be described with reference to FIGS. 4A to 4G and FIGS. 5A to 5G. 4A to 4G are used for the operation when focusing on the angular velocity component of the detection signal, and FIGS. 5A to 5G are for the operation when focusing on the self-vibration component of the detection signal. ). In the present embodiment, the angular velocity component of the detection signal output from the detection terminal 15 is a signal whose phase is 90 degrees behind the feedback signal output from the drive terminal 14 and is output from the detection terminal 15. It is assumed that the self-vibration component of the detection signal is a signal having the same phase as the feedback signal output from the drive terminal 14.

  First, the operation when focusing on the angular velocity component of the detection signal will be described. The angular velocity component of the detection signal output from the detection terminal 15 is converted into a charge voltage by the charge amplifier 311. At this time, the phase advances by 90 degrees. Therefore, the signal after being amplified by the differential amplifier 313 and the AC amplifier 314 has the same phase as the feedback signal shown in FIG. 4A, as shown in FIG.

  When the output signal of the AC amplifier 314 is synchronously detected by the synchronous detection circuit 321 based on the output signal of the comparator 24 shown in FIG. 4B, the output signal of the synchronous detection circuit 321 is the full wave shown in FIG. It becomes a rectified waveform. By integrating the output signal of the synchronous detection circuit 321 by the integration circuit 322, the angular velocity component of the detection signal can be output as a DC voltage. Thus, the angular velocity component extraction unit 32 can extract the angular velocity component of the detection signal. Further, the sensitivity can be adjusted by amplifying the signal with an AC amplifier circuit at the front stage of the integration circuit 322 or a DC amplifier 323 at the rear stage.

  On the other hand, when the synchronous detection circuit 335 performs synchronous detection on the output signal of the AC amplifier 314 and the output signal of the comparator 24 based on the signal (FIG. 4E) whose phase is advanced by 90 degrees by the phase shifter 334, the synchronous detection circuit The output signal 335 has a waveform shown in FIG. When the output signal of the synchronous detection circuit 335 is integrated by the integration circuit 336, the DC voltage becomes 0 as shown in FIG. Thus, the self-vibration component extracting unit 33 cancels the angular velocity component of the detection signal.

  Next, the operation when focusing on the self-vibration component of the detection signal will be described. The self-vibration component of the detection signal output from the detection terminal 15 is converted into a charge voltage by the charge amplifier 311. Then, the signal after being amplified by the differential amplifier 313 and the AC amplifier 314 is a signal whose phase is advanced by 90 degrees from the feedback signal shown in FIG. 5A, as shown in FIG. 5C.

  When the output signal of the AC amplifier 314 is synchronously detected by the synchronous detection circuit 321 based on the output signal of the comparator 24 shown in FIG. 5B, the output signal of the synchronous detection circuit 321 has the waveform shown in FIG. Become. When the output signal of the synchronous detection circuit 321 is integrated by the integration circuit 322, the DC voltage becomes zero. As described above, the angular velocity component extraction unit 32 cancels the self-vibration component of the detection signal.

  On the other hand, when the output signal of the AC amplifier 314 is synchronously detected by the synchronous detection circuit 335 on the basis of the output signal of the comparator 24 shown in FIG. The output signal 335 is a full-wave rectified waveform shown in FIG. When the output signal of the synchronous detection circuit 335 is integrated by the integration circuit 336, a DC voltage proportional to the wave height of the full-wave rectification waveform shown in FIG. 5F is obtained as shown in FIG. As described above, the self-vibration component extracting unit 33 can extract the self-vibration component of the detection signal.

  Further, the angular velocity detection circuit 5 according to the present embodiment may include a temperature characteristic correction unit 333. The temperature characteristic correction unit 333 corrects the variation of the output signal of the DC conversion unit 332 due to the temperature. For example, the temperature characteristic correction unit 333 can correct the magnitude of the output signal of the DC conversion unit 332 so that it is constant regardless of the temperature. For this reason, the fluctuation due to the temperature of the output signal of the DC conversion means 332 can be canceled, and the fluctuation due to the failure can be detected with high accuracy. Therefore, it is possible to realize an angular velocity detection circuit with improved vibrator failure detection accuracy.

  In addition, the inventors of the present application have found that the variation of the output signal of the DC conversion means 332 due to temperature can be approximated by a first-order gradient. Therefore, the temperature characteristic correcting unit 333 can be configured to correct the variation due to the temperature of the output signal of the DC converting unit 332 based on the first order term of the temperature characteristic of the output signal of the DC converting unit 332. .

  Further, the angular velocity detection circuit 5 includes storage means 337 for storing the first-order term of the temperature characteristic, and the temperature characteristic correction means 333 is the primary of the temperature characteristic stored in the storage means 337 as the output signal of the DC conversion means 332. Based on the term, it may be configured to correct the variation of the output signal of the DC conversion means 332 due to the temperature. The storage unit 337 can be configured by a nonvolatile memory such as an EEPROM, for example. Thereby, for example, in the inspection process of the angular velocity detection device 1, the output voltage of the temperature characteristic correction means 333 is measured, and the first term of the temperature characteristic such that the output voltage becomes a substantially constant value regardless of the temperature is stored in the storage means. 337 can be written. Therefore, even when the vibrator has different temperature characteristics, appropriate temperature characteristic correction can be performed.

  The angular velocity detection circuit 5 according to the present embodiment has an external terminal 340 that outputs the output signal Vout of the self-vibration component extraction unit 33, and an external failure determination circuit (not shown) outputs the voltage of the output signal Vout. Is higher than the upper reference value or lower than the lower reference value, it is determined that the vibrator 10 has a failure, and an output signal based on the determination result is output. Alternatively, the angular velocity detection circuit 5 may include a failure determination circuit 338 that determines whether or not there is a failure in the angular velocity detection device 1 based on the output signal Vout of the self-vibration component extraction unit 33. The failure determination circuit 338 determines that the vibrator 10 has a failure when the output signal Vout of the temperature characteristic correction unit 333 exceeds the upper limit reference value or falls below the lower limit reference value, and outputs based on the determination result. Output a signal. In the circuit block diagram shown in FIG. 1, an output signal is output to the outside of the angular velocity detection circuit 5 via the output terminal 341. Since the angular velocity detection circuit 5 includes the failure determination circuit 338, the angular velocity detection device 1 itself can determine whether or not the vibrator 10 has a failure.

  When there is a failure in the vibrator 10, for example, when a foreign object adheres to the vibrator 10 or the vibrator 10 is damaged, the magnitude of the self-vibration component based on the excitation vibration of the vibrator 10 changes. . Accordingly, the self-vibration component of the detection signal is extracted by the self-vibration component extraction unit 33, and the magnitude of the self-vibration component of the detection signal is monitored inside or outside the angular velocity detection device 1, whereby the vibrator 10 has a failure. It can be determined whether or not. For example, when the magnitude of the self-vibration component of the detection signal exceeds the upper limit reference value or falls below the lower limit reference value, it can be determined that the vibrator 10 has a failure.

  Furthermore, in the present embodiment, the self-vibration component output from the self-vibration component extraction unit 33 when the respective electrical connections between the detection terminals 15 and 16 and the detection circuit 30 are maintained (that is, in a normal state). The size of the vibrator 10 is set so as to be shifted from 0, and balance tuning is performed on the vibrator 10 so that it is preferably at least 1 time and less than 2 times the lower limit reference value. If any one of the electrical connection between the detection terminal 15 and the detection circuit 30 and the electrical connection between the detection terminal 16 and the detection circuit 30 is lost, the magnitude of the self-vibration component is normal. It becomes about 1/2 of. The self-vibration component having a magnitude of about ½ at normal time is less than the lower limit reference value defined by the failure determination circuit 338 or the failure determination circuit outside the angular velocity detection circuit 5. A determination circuit external to the circuit 338 or the angular velocity detection circuit 5 can determine that one of the two electrical connections has been broken.

  Note that the electrical connection between the detection terminal 15 and the detection circuit 30 and the electrical connection between the detection terminal 16 and the detection circuit 30 are realized via respective signal lines wire-bonded. .

  4). Disconnection detection Disconnection detection is performed as follows. If one of the detection terminals 15 and 16 is disconnected, the output of one of the charge amplifiers 311 and 312 is 0 V, and the amplitude of the output signal of the detection signal amplification unit shown in FIG. It becomes about 1/2. The amplitude of the full-wave rectified waveform shown in FIG. 5 (F) is also about ½ that when there is no disconnection. When the level difference between the DC voltage of the output signal (FIG. 5G) of the integration circuit 336 and the reference voltage, that is, the signal magnitude and the magnitude of the output signal output from the subsequent DC amplifier 339 are not disconnected. It becomes about 1/2 of.

When the output signal of the DC amplifier 339 deviates from the reference value, the failure determination circuit 338 or an external failure determination circuit (not shown) determines that there is a disconnection. Normally, it is ideal that only vibration (arrow D) based on the Coriolis force is generated in the detection vibrating arm 12. Therefore, vibrations other than vibrations based on Coriolis force are treated as spurious modes and eliminated. Therefore, balance tuning is performed so that there is no leakage of drive vibration. The vibrator 10 according to the present embodiment is a so-called WT type having a detection vibrating arm 12 that is sandwiched between driving vibration arms 11 extending in the + Y-axis and −Y-axis directions and extending in the + Y-axis and −Y-axis directions. It is a vibrator.
The feature of this WT type vibrator is that the drive vibrations leaking from the four drive vibration arms 11 are canceled with each other in the detection base 49, so that balance tuning can be performed so that the target value of the self-vibration component becomes zero. . However, in this embodiment, in order to enable disconnection detection, the voltage level output from the detection circuit 30 or the external terminal 340 as a self-vibration component is balanced so as to substantially deviate from a reference voltage (for example, 0 V). Tune. Here, the voltage level that the detection circuit 30 or the external terminal 340 outputs as a self-vibration component may be a level that does not cause an error in the disconnection determination, and is set to a target value, for example, 3.0V.

  In the balance tuning, a metal film such as Cr and Au is formed on the wide portion 43 of the drive vibration arm 11 and a drive signal is applied to the drive vibration arm 11 so that the self vibration component becomes a target value. As described above, the metal film is removed by using a technique such as laser irradiation or ion milling.

  DESCRIPTION OF SYMBOLS 1 ... Angular velocity detection apparatus, 5 ... Angular velocity detection circuit, 10 ... Vibrator, 11 ... Drive vibration arm, 12 ... Detection vibration arm, 13 ... Drive terminal, 14 ... Drive terminal, 15, 16 ... Detection terminal, 17 ... Grounding terminal 20 ... Drive circuit, 21 ... Current-voltage converter, 22 ... AC amplifier, 23 ... Automatic gain control circuit, 24 ... Comparator, 30 ... Detection circuit, 31 ... Detection signal amplification unit, 32 ... Angular velocity component extraction unit, 33 ... Self-vibration component extraction unit, 41... Drive electrode, 42... Drive electrode, 43 .. wide portion, 44 .. base for driving, 45 .. coupling arm, 46 a .. detection electrode, 47 a. Base, 311 ... Charge amplifier, 312 ... Charge amplifier, 313 ... Differential amplifier, 314 ... AC amplifier, 321 ... Synchronous detection circuit, 322 ... Integration circuit, 323 ... DC amplifier, 324 ... Output terminal, 331 Self vibration component extracting means, 332 ... DC converting means, 333 ... temperature characteristic correction unit, 334 ... phase shifter, 335 ... synchronous detection circuit, 336 ... integrating circuit, 339 ... DC amplifier, 343 ... AC amplifier.

The present invention can be realized as the following forms or application examples so as to solve the above-described problems.
A method of manufacturing an angular velocity detecting device according to an aspect of the present invention includes a detection vibration piece and a drive vibration piece, a component based on the Coriolis force of the drive vibration piece, and a self-vibration component based on the drive vibration of the drive vibration piece. And a detection circuit that extracts the self-vibration component from the signal, the method for manufacturing an angular velocity detection device, the self-vibration output from the detection circuit The method includes a step of balance tuning the component size to a value different from zero.
According to another aspect of the present invention, there is provided a method of manufacturing an angular velocity detection device, wherein the angular velocity detection device outputs a signal from the detection circuit to the outside.
According to another aspect of the present invention, there is provided a method of manufacturing an angular velocity detection device, wherein the angular velocity detection device includes a failure determination circuit to which a signal from the detection circuit is input, and the failure determination circuit is included in the failure determination circuit. When the magnitude of the signal from the input detection circuit is larger than an upper reference value, it is determined that the vibrator has failed.
According to another aspect of the present invention, there is provided a method of manufacturing an angular velocity detection device, wherein the angular velocity detection device includes a failure determination circuit to which a signal from the detection circuit is input, and the failure determination circuit is included in the failure determination circuit. When the magnitude of the signal from the input detection circuit is smaller than a lower limit reference value, it is determined that the vibrator has failed.
In a method of manufacturing an angular velocity detection device according to another aspect of the present invention, the balance tuning includes a step of forming a film on the driving vibration piece and removing a part of the film.
In the manufacturing method of the angular velocity detecting device according to another aspect of the present invention, the detection vibrating piece extends from the detection base, and the driving vibration piece is on both sides with respect to the detection vibrating piece. The vibration direction due to the drive vibration of the drive vibration piece and the vibration direction due to the Coriolis force of the detection vibration piece are in a substantially coplanar relationship.

Claims (5)

A detection vibration piece extending from the detection base, and a drive vibration piece disposed on both sides with respect to the detection vibration piece, a vibration direction due to drive vibration of the drive vibration piece, A vibrator that outputs a signal including a component based on the Coriolis force and a self-vibration component based on the driving vibration, and a vibration direction due to the Coriolis force of the detection vibrating piece is in a substantially coplanar relationship;
A detection circuit for extracting the self-vibration component from the signal;
A failure determination circuit to which a signal from the detection circuit is input;
A method of manufacturing an angular velocity detection device comprising:
A method for manufacturing an angular velocity detecting device, comprising: balancing tuning the magnitude of the self-vibration component output from the detection circuit to a value different from zero.   The method of manufacturing an angular velocity detection device according to claim 1, wherein the balance tuning includes a step of forming a film on the drive vibrating piece and removing a part of the film.   The failure determination circuit determines that the vibrator has failed when a magnitude of a signal from the detection circuit input to the failure determination circuit decreases. Manufacturing method of angular velocity detection device.   2. The magnitude of a signal from the detection circuit input to the failure determination circuit is at least 1 and less than 2 times a lower limit reference value defined by the failure determination circuit as a normal value. The manufacturing method of the angular velocity detection apparatus as described in any one of Claims 1-3.   The vibrator includes a connection arm extending from the detection base in a direction intersecting with an extension direction of the detection vibration piece, a drive base disposed on the connection arm, and the drive base. 5. The method of manufacturing an angular velocity detection device according to claim 1, further comprising: the drive vibration piece extending from the drive shaft.

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