JP2001264069A - Angular velocity sensor - Google Patents

Abstract

(57) [Summary] (With correction) [Problem] To provide an angular velocity sensor that can be miniaturized with high accuracy. SOLUTION: First and second driving vibrators 16, 17 are:
It is arranged substantially symmetrically with respect to the point O. The driving-side vibrator 13 is
The driving vibrators 16, which are formed in a substantially symmetrical frame shape with respect to the point O,
Surround 17. The driving vibrators 16 and 17 are respectively symmetric with respect to the driving-side vibrator 13 via the first driving springs 41 and 42 and the second driving springs 43 and 44 symmetrically with respect to the y direction passing through the point O. Floating supported so that it can vibrate in the direction. The detection oscillator 12 is formed in a substantially symmetrical frame shape with respect to the point O, and surrounds the driving-side oscillator 13. The detection vibrator 12 and the drive-side vibrator 13 are supported by the stress relieving frame 11 via the detection springs 33 and 34 so as to be capable of torsional rotational vibration in opposite phases around the z-axis passing through the point O with respect to each other. Drive vibrator 1
6 and 17 are coupled via a drive common-mode countermeasure spring 45.
The angular velocity is detected by the torsional rotational vibration around the z-axis passing through the point O of the detection vibrator 12 in a state where the driving vibrators 16 and 17 are vibrated and driven in the x direction in opposite phases.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an angular velocity sensor having a vibrator floatingly supported on a substrate and detecting an angular velocity based on a vibration state of the vibrator.

[0002]

2. Description of the Related Art Conventionally, as an angular velocity sensor, for example, one described in Japanese Patent No. 2888029 is known. The angular velocity sensor is supported on a substrate via a first support beam so as to be capable of vibrating in a driving direction (x direction).
And a second vibrating body supported by the first vibrating body via a second support beam so as to be able to vibrate in the detection direction (y-direction). Then, in a state where the first vibrating body is driven to vibrate in the driving direction together with the second vibrating body, z
When an angular velocity around the axis is applied, the second vibrating body vibrates in the detection direction according to Coriolis force based on the angular velocity.
The angular velocity sensor detects a change in stress of the second support beam based on the vibration in the detection direction of the second vibrating body as the applied angular velocity.

[0003]

In this angular velocity sensor, the first vibrating body is supported by the first support beam so as to easily vibrate only in the driving direction, and the second vibrating body is supported by the second supporting beam. It is easily supported by beams only in the detection direction. In other words, a vibrating body for driving (first vibrating body)
And a spring (second support beam) that supports a vibrating body for detection (a second vibrating body). In such an angular velocity sensor, in order to secure its sensitivity and responsiveness,
It is general that the resonance frequency in the driving direction and the resonance frequency in the detection direction are slightly shifted from each other. As a result, mechanical coupling caused by unexpected vibration due to manufacturing variations and stress due to thermal expansion of the substrate is reduced. However, since the angular velocity is detected based on the vibration of only one vibrating body (the second vibrating body), for example, in an environment where there is a lot of vibration such as when mounted on a vehicle, acceleration such as acceleration acting in a predetermined direction upon detection is detected. The factor of the external force cannot be separated, and the detection accuracy of the angular velocity must be reduced.

Therefore, as described in, for example, JP-A-2000-9470, a pair of drive frames (first and second drive frames) and detection frames (first and second detection frames) according to the above are provided. 2. Description of the Related Art An angular velocity sensor configured as a tuning fork in a plane has been known. The angular velocity sensor vibrates the first drive frame and the second drive frame in opposite phases in the drive direction, so that the first detection frame and the second detection frame similarly oscillate in opposite phases in the drive direction. In this state, when an angular velocity about the z-axis passing through the point O is applied, the first detection frame and the second detection frame vibrate in the detection direction according to Coriolis force based on the angular velocity. At this time, since the first detection frame and the second detection frame vibrate in opposite phases in the driving direction, the vibrations in the detection directions also have opposite phases. Therefore, by differentially amplifying each vibration detection signal based on the vibration in the detection direction of the first detection frame and the second detection frame, the signal level is approximately doubled and the noise detected in the same phase is substantially reduced. cancel. Therefore, for example, the first force such as an external force such as acceleration
Factors that affect the detection frame and the second detection frame in the same phase can be substantially cancelled, and the detection accuracy of the angular velocity can be improved.

[0005] However, in this angular velocity sensor, although consideration has been given to cooperating vibration of the first drive frame and the second drive frame, the angular velocity sensor is coupled to the first detection frame and the second detection frame. Therefore, the first detection frame and the second detection frame have unstable vibrations in the detection direction. In particular, if the amplitudes of the vibrations are different due to the difference in the sensitivity of the vibration in the detection direction of the first detection frame and the second detection frame, it is not possible to sufficiently cancel the above-described factors having the same phase. For this reason, in an environment where there is a lot of vibration such as when the vehicle is mounted on a vehicle, for example, an angular velocity detection error must be generated.

Further, in this angular velocity sensor, the first and second drive frames and the first and second detection frames are supported at the positions of immovable parts (points) in the vibration mode during driving and the vibration mode during detection. For example, mechanical coupling occurs due to unexpected vibration caused by stress due to, for example, manufacturing variations or thermal expansion of the substrate, and an error in angular velocity detection increases.

In view of these problems, Japanese Patent Laid-Open Publication
An angular velocity sensor as described in JP-A-9472 is also known. The angular velocity sensor described in the publication includes a pair of coupled x vibrators, a ring-shaped detection vibrator provided on the outer peripheral side thereof, and a rotation of the x vibrator and the detection vibrator around a z-axis passing through a point O. And a connecting beam that is connected to be capable of torsional rotational vibration in opposite phases. When an angular velocity about the z-axis passing through the point O is applied in a state where the x-vibrators are driven to vibrate in the x-direction in mutually opposite phases, the x-vibrators have a relatively opposite phase based on the same angular velocity. The connection beam is bent by the elliptical vibration, and the detection vibrator is torsionally oscillated. By detecting the torsional rotational vibration of the detection vibrator, the applied angular velocity is detected.

In this angular velocity sensor, coupling of a pair of x vibrators is realized, and the detection vibrator also has a ring-shaped integral shape and performs stable vibration. Further, this angular velocity sensor is supported at a point O which is a position of a fixed part (point) common to the vibration mode at the time of driving and the vibration mode at the time of detection, and addresses the above-described problem.

However, in this angular velocity sensor, it is basically necessary to support the pair of x-vibrators in the x-direction so as to be able to vibrate in opposite phases to each other and the detection vibrator to be capable of torsional rotational vibration only at the point O. Therefore, there is another problem that the supporting strength of the angular velocity sensor needs to be increased, and the angular velocity sensor must be increased in size.

It is an object of the present invention to provide an angular velocity sensor which has high accuracy and can be downsized.

[0011]

In order to solve the above-mentioned problems, the invention according to claim 1 is based on a first driving vibrator and a second driving vibration arranged substantially symmetrically with respect to a point O on an xy plane. A driving-side vibrator formed in a frame shape of one of a substantially circular shape and a substantially polygonal shape substantially symmetrical with respect to the point O and surrounding the first driving vibrator and the second driving vibrator; A detection vibrator formed in a substantially symmetrical substantially circular or substantially polygonal frame shape and surrounding the driving-side vibrator;
A first driving vibrator that floats and supports the first driving vibrator and the second driving vibrator in the x direction with respect to the driving vibrator so as to be substantially symmetric with respect to the y direction passing through the point O; A z-axis passing through a point O with respect to a connection portion between a spring and a second driving spring, and a connection portion between the driving-side vibrator and the detection vibrator and a substrate disposed between the driving-side vibrator and the detection vibrator; A plurality of detection springs floatingly supported so as to be capable of torsional rotational vibration having opposite phases to each other, and the first drive vibrator and the second drive vibrator interposed between the first drive vibrator and the second drive vibrator. A coupling spring for coupling vibration, a driving means for oscillatingly driving the first driving vibrator and the second driving vibrator in the x direction in opposite phases, and a torsion around the z-axis passing through a point O of the detection vibrator. The gist of the present invention is to provide a detecting means for detecting the rotational vibration.

According to a second aspect of the present invention, in the angular velocity sensor according to the first aspect, the connection portion with the substrate is formed such that the driving-side vibrator and the detection vibrator are connected to each other around a z-axis passing through a point O. The gist is that it substantially coincides with the node at the time of the torsional rotational vibration having the opposite phase.

[0013] The invention according to claim 3 is the invention according to claim 1 or 2.
In the angular velocity sensor described in the above, a stress relaxation frame formed in any one of a substantially circular or substantially polygonal frame substantially symmetric with respect to a point O and disposed between the drive-side vibrator and the detection vibrator, A stress relaxation spring for floatingly supporting the stress relaxation frame on the xy plane with respect to the substrate so that the stress relaxation frame can be oscillated on the xy plane. A connection portion with the substrate is connected to the substrate via the stress relaxation frame and the stress relaxation spring. That is the gist.

(Operation) According to the first aspect of the present invention,
The first driving vibrator and the second driving vibrator are driven by the driving means to vibrate in the x direction in mutually opposite phases. In other words, the first driving vibrator and the second driving vibrator are resonance tuning fork vibrations stable in the x direction, and have high energy consumption rates. Then, the vibrations in the x direction transmitted from, for example, the first driving vibrator and the second driving vibrator to, for example, the driving vibrator and the detection vibrator are substantially canceled as a whole.

Further, the first driving vibrator and the second driving vibrator vibrate in a coupled manner due to the interposed coupling spring. Therefore, in-phase vibration modes that occur when the first driving vibrator and the second driving vibrator are separately provided, for example, are eliminated. For this reason, even in an environment where there is a lot of vibration, for example, when mounted on a vehicle, the first driving vibrator and the second driving vibrator operate stably.

When an angular velocity about the z-axis passing through the point O is applied in a state where the first driving vibrator and the second driving vibrator are driven to vibrate in the x direction in opposite phases to each other, Coriolis force corresponding to the same angular velocity is applied. Accordingly, the first driving vibrator and the second driving vibrator perform elliptical vibrations having y components having phases opposite to each other.
Rotational vibrations are induced by the respective elliptical vibrations of the first driving vibrator and the second driving vibrator, and the driving-side vibrator and the detection vibrator are torsional rotationally vibrate around the z-axis passing through the point O in opposite phases. The applied angular velocity is detected by detecting the torsional rotational vibration of the detection vibrator by the detection means. Since the torsional rotational vibrations of the drive-side vibrator and the detection vibrator having phases opposite to each other are based on the vibration of the detection spring provided separately from the first and second driving springs, for example, Mechanical coupling between the first and second driving vibrators and the driving-side vibrator and the detecting vibrator is suppressed.

If the first and second driving vibrators are driven to vibrate obliquely in the x direction in opposite phases to each other due to, for example, manufacturing variations, the diagonal vibration is caused by the driving side vibrator and the detection vibration. It does not induce torsional rotational vibration on the child.

On the other hand, even when the first and second driving vibrators are driven to vibrate obliquely in the predetermined direction in the same phase with each other due to, for example, acceleration applied in a predetermined direction, the driving-side vibrator and the detecting vibrator are not driven. This oblique vibration does not induce torsional rotational vibration with respect to the drive-side vibrator and the detection vibrator, because the vibrator is formed in one of a substantially circular frame and a substantially polygonal frame.

Further, the drive-side vibrator and the detection vibrator are driven to vibrate in opposite phases so as to substantially cancel out the torsional rotational vibrations of the drive-side vibrator and the detection vibrator. Propagation of each torsional rotational vibration of the drive-side vibrator and the detection vibrator to the substrate is suppressed.

On the other hand, a detection vibrator is disposed on the outer peripheral side of the connection portion with the substrate, and a driving side vibrator and first and second driving vibrators are disposed on the point O side. It is a mode to balance these. Therefore, by dividing the weight of the floating supported structure by approximately two, the supporting strength required for the detection spring, for example, the cross-sectional area of the detection spring is reduced, and the size of the angular velocity sensor can be reduced. Can be

By simultaneously realizing the above operations, there is provided an angular velocity sensor capable of achieving high accuracy and downsizing. According to the second aspect of the present invention, the connection portion with the substrate is a node when the drive-side vibrator and the detection vibrator perform torsional rotational vibrations around the z-axis passing through the point O and having opposite phases to each other. Approximately matches. Accordingly, the mechanical coupling between the driving-side vibrator (the first and second driving vibrators) and the detection vibrator due to unexpected vibration due to, for example, manufacturing variations or stress due to thermal expansion of the substrate is significantly reduced. In addition, the detection accuracy of the angular velocity is improved even in an environment where there is a lot of vibration such as when mounted on a vehicle.

According to the third aspect of the present invention, the connection portion with the substrate is connected to the substrate via the stress relaxation frame and the stress relaxation spring. Therefore, transmission of stress from the substrate due to, for example, an external temperature change or the application of an external force or the like is reduced to the detection vibrator (sensor) side.

Further, the resonance frequencies of the torsional rotational vibrations of the driving-side vibrator and the detection vibrator connected to the substrate via the stress relaxation frame and the stress relaxation spring, which are in opposite phases, are shifted from the resonance frequency at the time of driving. In addition, the responsiveness of the angular velocity sensor is ensured.

[0024]

DESCRIPTION OF THE PREFERRED EMBODIMENTS (First Embodiment) A first embodiment of an angular velocity sensor according to the present invention will be described below with reference to FIGS.

As shown in FIG. 1, a silicon substrate 10 as a substrate on which an insulating layer is to be formed is provided with, for example, polysilicon doped with impurities to make it conductive (hereinafter referred to as “conductive polysilicon”). The stress relaxation frame 11, the detection vibrator 12, the driving vibrator 13, the first driving vibrator 16, the second driving vibrator 17, the first driving force applying fixed electrode 21, the second driving force applying fixed formed by Electrode 22, first drive displacement detection fixed electrode 23, second drive displacement detection fixed electrode 24, first
Angular velocity detection fixed electrode 25, second angular velocity detection fixed electrode 26
And floating body anchors a10, a11, and a12. The first and second driving force applying fixed electrodes 2
1, 22; first and second drive displacement detection fixed electrodes 23, 2
4. The first and second angular velocity detecting fixed electrodes 25 and 26 and the floating anchors a10 to a12 are joined to the silicon substrate 10. Further, the floating body anchor a10 is disposed substantially coincident with the point O. The angular velocity sensor is provided substantially symmetrically on the xy plane with respect to the point O.

The stress relaxation frame 11 is formed in a substantially octagonal frame shape, and its center on the xy plane substantially coincides with the point O. On one side and the other side of the stress relaxation frame 11 in the x and y directions (the right and left sides of FIG. 1, the upper and lower sides), the point O side substantially along the x and y directions passing through the point O, respectively. A protruding protrusion 11a is formed. The stress relaxation frame 11 includes a pair of substrate stress relaxation springs 31 made of conductive polysilicon, which are disposed so as to sandwich a substantially central portion in the circumferential direction of each protrusion 11a.
32, they are connected to the floating body anchors a11 and a12, respectively. The stress relaxation frame 11 and the substrate stress relaxation springs 31 and 32 are formed so as to float from the silicon substrate 10 by, for example, lithographic semiconductor processing.

Each of the substrate stress relaxation springs 31 and 32 is bent and formed so as to extend in a direction opposite to the direction in which the protrusion 11a protrudes, and has substantially the same shape except that it is substantially symmetric. I have. These substrate stress relaxation springs 31 and 3
No. 2 is formed to have high flexibility in the rotation direction around the z-axis about the point O, and for example, stress from the silicon substrate 10 due to an external temperature change or application of an external force is transmitted to the sensor side. To relax.

The detection vibrator 12 is mounted on the stress relaxation frame 1.
1 is formed in a substantially octagonal frame shape so as to surround the point 1, and the center of the xy plane substantially coincides with the point O. The detection vibrator 12 is located on one side and the other side in the x direction passing through the point O (FIG. 1).
(The right side and the left side of the figure), is connected to the stress relaxation frame 11 and the driving-side vibrator 13 via a conductive polysilicon detecting spring 33 extending inward in the x direction. Also,
The detection vibrator 12 is provided on one side and the other side (upper and lower sides in FIG. 1) in the y direction passing through the point O via a conductive polysilicon detection spring 34 extending inward in the y direction. 11 and the driving-side vibrator 13.

Note that the detection oscillator 12, the drive-side oscillator 13, and the detection springs 33 and 34 are also formed on the silicon substrate 10 by, for example, lithographic semiconductor processing.
It is formed so as to float from.

The detection springs 33 and 34 pass between the substrate stress relieving spring 31 (floating body anchor a11) and the substrate stress relieving spring 32 (floating body anchor a12) and substantially extend in the circumferential direction of the protrusion 11a. In the middle part, it is continuous with the stress relaxation frame 11. The connection portions of the detection springs 33 and 34 to the stress relaxation frame 11 are torsional rotational vibrations having opposite phases around the z-axis around the point O of the detection vibrator 12 and the drive-side vibrator 13. Is set at the position of the immovable part (knot). Therefore, the influence of the stress relaxation frame 11 on the torsional rotational vibrations of the detection vibrator 12 and the drive-side vibrator 13 having the opposite phases to each other is small.

The detection springs 33 and 34 that support the detection vibrator 12 and the driving-side vibrator 13 are arranged so as to extend in the cross direction (the x direction and the y direction passing through the point O). The postures of the detection vibrator 12 and the drive-side vibrator 13 are maintained parallel to the silicon substrate 10. Since the detection springs 33 and 34 are formed to have high flexibility in the rotation direction about the z-axis about the point O, the detection springs 33 and 34 are set at the point O of the detection vibrator 12 and the drive-side vibrator 13. , The respective torsional rotations around the z-axis are facilitated.

The detection vibrator 12 has a plurality of substantially quadrangular detection windows 36 arranged side by side along each side, and a bridge beam for partitioning each adjacent detection window 36 is an angular velocity detection movable electrode. 37. The detection vibrator 12 (angular velocity detection movable electrode 37) is caused to rotate between the first and second angular velocity detection fixed electrodes 25 and 26 by torsional rotational vibration about the z-axis about the point O of the detection vibrator 12. The capacitance at

The driving-side vibrator 13 is formed in a substantially octagonal frame shape so as to be surrounded by the stress relaxation frame 11.
The center on the xy plane also substantially coincides with the point O. On one side and the other side (the right side and the left side in FIG. 1) of the drive-side vibrator 13 in the x direction, first protrusions 13a projecting toward the point O substantially along the x direction passing through the point O are formed. ing. Further, one side and the other side in the y direction of the driving side vibrator 13 (FIG. 1)
(Upper side and lower side) are formed with second protrusions 13b that protrude toward the point O substantially along the y direction passing through the point O. The drive-side vibrator 13 is continuous with the detection springs 33 and 34 (stress relaxation frame 11) at substantially middle portions in the circumferential direction of the first and second protrusions 13a and 13b. Further, the drive-side vibrator 13 is connected to the floating body anchor a10 via a conductive polysilicon detecting spring 38 extending inward in the y direction from each of the second protrusions 13b.

The detection spring 38 is also formed so as to float from the silicon substrate 10 by, for example, lithographic semiconductor processing, and has flexibility in a rotational direction about the z-axis about the point O. Since it is formed high, the torsional rotation around the z-axis around the point O of the driving-side vibrator 13 is easy.

The first driving vibrator 16 passes through the point O
It is arranged on one side in the x direction (the right side in FIG. 1) with respect to the axis so as to be surrounded by the driving-side vibrator 13. The first driving vibrator 16 includes inclined portions 16a on one side and the other side in the y direction.
Is formed in a substantially trapezoidal frame narrowed to one side in the x-direction (the right side in FIG. 1) via. This first driving vibrator 16
The driving-side vibrator is provided via a first driving spring 41 of conductive polysilicon provided between an outer wall surface on the outer side in the x direction (right side in FIG. 1) and an inner wall surface facing the driving-side vibrator 13. 13 in succession. Further, the first driving vibrator 1
Reference numeral 6 denotes a first driving spring 42 made of conductive polysilicon provided between the opposing second protrusions 13b of the driving-side vibrator 13 on one side and the other side in the y direction of the outer wall surface on the center side.
And is connected to the same drive-side vibrator 13 via the.

The first driving vibrator 16 and the first driving springs 41 and 42 are also formed so as to float from the silicon substrate 10 by, for example, lithographic semiconductor processing. The first driving springs 41, 42
Is bent and formed so as to extend in the y-direction so as to increase flexibility only in the x-direction.

A driving force applying movable electrode 16b extending along the y-direction at a substantially intermediate portion in the x-direction is formed on the short width side frame of the first driving vibrator 16. The driving force applying movable electrode 16b is a substantially comb-shaped electrode extending on each side in the x direction at a predetermined interval in the y direction. The driving force applying movable electrode 16b is connected to the first and second driving force applying fixed electrodes 21 and 22 by a driving signal supplied to the first and second driving force applying fixed electrodes 21 and 22. The attraction force is periodically fluctuated, causing the first driving vibrator 16 to generate vibration in the x direction.

A drive displacement detecting movable electrode 16c extending along the y-direction at a substantially intermediate portion in the x-direction is formed in the frame on the long width side of the first drive vibrator 16. The drive displacement detection movable electrode 16c is also a substantially comb-shaped electrode extending on each side in the x direction at a predetermined interval in the y direction. The driving displacement detecting movable electrode 16c is connected to the first driving vibrator 16
The capacitance between the first and second drive displacement detection fixed electrodes 23 and 24 is varied by the vibration in the x direction.

On the other hand, the second driving vibrator 17 is arranged so as to be substantially symmetrical to the first driving vibrator 16 with respect to the y-axis passing through the point O and surrounded by the driving-side vibrator 13. The second driving vibrator 17 is similarly formed in a substantially trapezoidal frame narrowed to the other side in the x direction (the left side in FIG. 1) via each inclined portion 17a on one side and the other side in the y direction. I have. The second driving vibrator 17 is a second driving spring made of conductive polysilicon provided between the outer wall surface on the outer side in the x direction (left side in FIG. 1) and the inner wall surface facing the driving-side vibrator 13. It is connected to the same drive side vibrator 13 via 43. The second driving vibrator 17 is formed of a conductive polymer provided between the opposing second protrusions 13b of the driving-side vibrator 13 on one side and the other side of the outer wall on the center side in the y direction. Silicon second
It is connected to the driving-side vibrator 13 via a driving spring 44.

The second driving vibrator 17 and the second driving springs 43 and 44 are also formed so as to float from the silicon substrate 10 by, for example, lithographic semiconductor processing, and have flexibility only in the x direction. Y to be high
It is bent to extend in the direction.

The second driving vibrator 17 has the same driving force applying movable electrode 17b as the driving force applying movable electrode 16b.
Are formed. This driving force applying movable electrode 17b also
The electrostatic attraction between the first and second driving force applying fixed electrodes 21 and 22 is periodically changed by the driving signal supplied to the first and second driving force applying fixed electrodes 21 and 22,
The second drive vibrator 17 generates vibration in the x direction.

The second drive vibrator 17 also has a drive displacement detection movable electrode 17c similar to the drive displacement detection movable electrode 16c. The drive displacement detection movable electrode 17c also varies the capacitance between the first and second drive displacement detection fixed electrodes 23 and 24 by the vibration of the second drive vibrator 17 in the x direction.

The first and second driving vibrators 16,
Since the drive signal 17 is arranged substantially symmetrically with respect to the y-axis passing through the point O, the drive signals supplied to the first and second drive vibrators 16 and 17 have opposite phases. Accordingly, as exaggeratedly shown in FIG. 4, the first and second driving vibrators 16 and 17 vibrate in the x direction in mutually opposite phases. That is, the first and second driving vibrators 16 and 17 have x
It is a resonance tuning fork vibration that is stable in the direction, and has a high energy consumption rate. The capacitance variations between the drive displacement detection movable electrodes 16c and 17c and the first and second drive displacement detection fixed electrodes 23 and 24 are also in opposite phases.

Here, the first and second driving vibrators 1
The opposing wall surfaces 6 and 17 are connected via a driving common-mode countermeasure spring 45 as a coupling spring made of conductive polysilicon which is substantially symmetric with respect to the x-axis and the y-axis passing through the point O. The drive common-mode countermeasure spring 45 is also formed so as to float from the silicon substrate 10 by, for example, lithographic semiconductor processing, and has a high flexibility only in the x direction.
It is bent so as to extend outward in both directions. Since the first and second driving vibrators 16 and 17 are coupled and vibrated by the driving in-phase countermeasure spring 45, the in-phase vibration mode is eliminated. Therefore, even in an environment where there is a lot of vibration such as when mounted on a vehicle, for example,
The driving oscillators 16 and 17 operate stably.

The first driving force applying fixed electrode 21 is substantially along the y direction in a frame outside the x direction of the driving force applying movable electrodes 16b and 17b of the first and second driving vibrators 16 and 17. The driving force applying movable electrode 16 is formed.
It is a substantially comb-shaped electrode extending alternately in the x direction with respect to b and 17b. Similarly, the second driving force applying fixed electrode 22 is connected to the first and second driving vibrators 16 and 1.
7 are formed substantially along the y direction in the frame inside the x direction of the driving force applying movable electrodes 16b and 17b, and extend approximately in the x direction with respect to the driving force applying movable electrodes 16b and 17b. It is a tooth-like electrode. These first
The second driving force applying fixed electrodes 21 and 22 periodically change electrostatic attraction between the driving force applying movable electrodes 16b and 17b, respectively, by applying a driving signal (voltage). The first and second driving vibrators 16 and 17 are vibrated in the x direction in opposite phases to each other. At this time, the first and second driving vibrators 16 and 17 are excited in the x direction at the resonance frequency by the application of the driving voltage.

Incidentally, the first and second driving vibrators 1
The first and second driving vibrators 1 and 6 are connected to the driving-side vibrator 13 via first driving springs 41 and 42 and second driving springs 43 and 44, respectively.
The vibrations in the x-direction transmitted to the same drive-side vibrator 13 are substantially canceled as a whole because the vibrations 6 and 17 are out of phase with each other in the x-direction.

When an angular velocity about the z-axis passing through the point O is applied in a state where the first and second driving vibrators 16 and 17 are vibrating in a resonance tuning fork in the x direction, the first and second driving vibrators 16 and 17 are driven. , 17 perform relatively elliptical elliptical vibrations having mutually opposite y-direction vibration components by Coriolis force based on the angular velocity. At this time, the first and second driving vibrators 16 and 17 have the first driving springs 41 and 42 and the second driving springs 43 and 44 having high flexibility only in the x direction.
Is connected to the driving-side vibrator 13, torsional rotational vibration around the z-axis passing through the point O is induced in the driving-side vibrator 13. At this time, each connection between the stress relaxation frame 11 and the detection springs 33 and 34 is connected to the detection vibrator 12.
Since the drive-side vibrator 13 is set at the position of the non-moving part (node) of the torsional rotational vibration having the opposite phase around the z-axis around the point O of the drive-side vibrator 13, as shown in FIG. The detection vibrator 12 and the drive-side vibrator 13 perform torsional rotational vibrations having phases opposite to each other. In other words, since the torsional rotational vibrations of the detection vibrator 12 and the drive-side vibrator 13 related to the detection are in opposite phases to each other, the propagation of the vibration to the silicon substrate 10 is suppressed.

The stress relaxation frame 11 is supported by the silicon substrate 10 (floating body anchors a11 and a12) via substrate stress relaxation springs 31 and 32 so as to be rotatable around the z-axis passing through the point O. Therefore, the resonance frequencies of the torsional rotational vibrations of the detection vibrator 12 and the driving-side vibrator 13 having the stress relaxation frame 11 as the immovable part (node), which are in opposite phases to each other, are shifted from the resonance frequency at the time of driving. Therefore, the responsiveness of the angular velocity sensor is ensured.

The first drive displacement detection fixed electrode 23 is located within the frame outside the x direction of the drive displacement detection movable electrodes 16c and 17c of the first and second drive vibrators 16 and 17, respectively.
It is formed substantially along the direction, and is a substantially comb-shaped electrode that extends alternately in the x direction with respect to the drive displacement detection movable electrodes 16c and 17c. Similarly, the second drive displacement detection fixed electrode 24 is substantially along the y direction within the frame inside the x direction of each drive displacement detection movable electrode 16c, 17c of the first and second drive vibrators 16, 17. It is a substantially comb-shaped electrode that extends alternately in the x direction with respect to the drive displacement detection movable electrodes 16c and 17c.

The first and second driving displacement detecting fixed electrodes 23 and 24 are connected to the first and second driving vibrators 16 and 17 respectively.
First and second driving vibrators 1 based on the vibration in the x direction
The vibration states of the first and second driving vibrators 16 and 17 in the x direction are detected by the vibration of the capacitance between the first and second driving vibrators 16 and 17 (driving displacement detection movable electrodes 16c and 17c). That is, when the first driving vibrator 16 moves outward in the x direction (right side in FIG. 1), the capacitance between the first driving displacement detection fixed electrode 23 and the driving displacement detection movable electrode 16c decreases, and The capacitance between the second drive displacement detection fixed electrode 24 and the same drive displacement detection movable electrode 16c increases. When the first drive oscillator 16 moves inward in the x direction (left side in FIG. 1), these relationships are reversed. On the other hand, when the second drive vibrator 17 moves outward in the x direction (left side in FIG. 1), the capacitance between the first drive displacement detection fixed electrode 23 and the drive displacement detection movable electrode 17c decreases, and The capacitance between the second drive displacement detection fixed electrode 24 and the drive displacement detection movable electrode 17c increases. Also, the second
When the driving oscillator 17 moves inward in the x direction (the right side in FIG. 1), these relationships are reversed. Therefore, the first
The capacitance vibrations of the fixed electrodes 23 and 24 are opposite to each other. Further, the first and second driving vibrators 16 and 17 respond to the first vibrations in the respective x directions.
The vibrations of the capacitances of the fixed electrodes 23 and 24 for detecting the second drive displacement are also in opposite phases.

The first and second angular velocity detecting fixed electrodes 2
Reference numerals 5 and 26 denote parallel plate electrodes formed in the respective detection windows 36 of the detection vibrator 12 so as to appear in a direction substantially perpendicular to the sides of the detection vibrator 12. These first and second angular velocity detection fixed electrodes 25 and 26 are connected to the same detection vibrator 12 (angular velocity detection movable electrode 37) based on torsional rotational vibration around the z-axis about the point O of the detection vibrator 12. The state of the torsional rotational vibration about the z-axis around the point O of the detection vibrator 12 is detected by the vibration of the capacitance between the two. That is, when the detection oscillator 12 is twisted and rotated to one side (clockwise in FIG. 1) around the z-axis about the point O, the distance between the detection oscillator 12 and the first angular velocity detection fixed electrode 25 is reduced. As the capacitance decreases, the capacitance between the detection vibrator 12 and the second angular velocity detection fixed electrode 26 increases. When the detection vibrator 12 is twisted to the other side (counterclockwise in FIG. 1) around the z-axis about the point O, these relationships are reversed. That is, the oscillations of the capacitances of the first and second angular velocity detection fixed electrodes 25 and 26 are in opposite phases.

Z about the point O of the detection transducer 12 as a center
The applied angular velocity about the z-axis is detected based on the state of the torsional rotational vibration about the axis. Note that even if the driving force applying movable electrode 17b, the first and second driving force applying fixed electrodes 21, 22 and the driving displacement detecting movable electrode 17c, and the first and second driving displacement detecting fixed electrodes 23, 24 are functionally interchanged. Good. The same applies to the right electrode with respect to the point O.

Next, an electrical configuration related to the angular velocity detection of the angular velocity sensor will be described with reference to FIG. As shown in FIG. 2, the timing signal generator 51
And a driving pulse signal for driving the second driving vibrators 16 and 17 in opposite phase in the x direction at the resonance frequency and outputting the driving pulse signals to the driving circuits 52 and 53 and synchronizing the synchronizing signal for synchronizing detection. Output to the circuits 54, 55, 56.

The drive circuits 52 and 53 synchronize with the drive pulse signals to generate drive signals (voltages) A,
B are first and second driving force applying fixed electrodes 21 and 2, respectively.
2 As shown in the drawing, these drive signals (voltages) A and B are output drive voltages V1 and
V2. The first and second driving vibrators 16,
Reference numeral 17 indicates that the driving signals (voltages) A and B are applied to the first and second driving force application fixed electrodes 21 and 22, thereby being driven to vibrate in the x direction. At this time, the first driving vibrator 16 and the second driving vibrator 17 vibrate in the x direction in opposite phases to each other. The capacitances of the first and second drive displacement detection fixed electrodes 23 and 24 vibrate in opposite phases.
Further, the first and second driving displacement detection fixed electrodes 2 with respect to the vibrations of the first and second driving vibrators 16 and 17 in each x direction.
The oscillations of the capacitances 3 and 24 are also in opposite phases. The charge amplifiers 57, 58, 59, 60 convert these vibrations of the capacitance into voltage vibrations. Differential amplifier 61
Differentially amplifies signals of opposite phases from the charge amplifiers 57 and 58, and makes the level (amplitude) of the signals approximately double,
Generates a differentially amplified signal that cancels noise. Then, the differential amplifier 61 outputs the differential amplified signal to the synchronous detection circuit 54 and the feedback processing circuit 63. Similarly, the differential amplifier 62 differentially amplifies the signals from the charge amplifiers 59 and 60 and reduces the level (amplitude) of the signals by approximately two.
A differential amplified signal is generated by canceling the noise. Then, the differential amplifier 62 outputs the differential amplified signal to the synchronous detection circuit 55 and the feedback processing circuit 63.

Synchronous detection circuits 54 and 55 are provided with differential amplifiers 61 and 62 in synchronization with a synchronous signal having the same phase as the drive pulse signal.
, Ie, detection signals (voltages) representing the x-direction vibrations of the first and second driving vibrators 16 and 17 corresponding to the phase shift of the same x-direction vibration with respect to the driving pulse signal. And outputs it to the feedback processing circuit 63.

The feedback processing circuit 63 outputs a phase shift signal for adjusting the level of the signal corresponding to the phase shift from the synchronous detection circuits 54 and 55 to the set value to the drive circuits 52 and 53. The drive circuits 52 and 53 shift the phases of the output drive voltages V1 and V2 of the drive signals (voltages) A and B with respect to the drive pulse signal in response to the phase shift signal. When the level of the signal corresponding to the phase shift of the synchronous detection circuits 54 and 55 substantially reaches the set value, the first
And the resonance tuning fork vibration of the second driving vibrators 16 and 17 becomes stable.

In a state where the first and second driving vibrators 16 and 17 are performing stable resonance tuning fork vibrations, when an angular velocity about the z-axis passing through the point O is applied, the detecting vibrator 12 and the driving vibrator 13 , Torsional rotational vibrations having phases opposite to each other are generated.

When torsional rotational vibration is generated in the detecting vibrator 12, the first and second angular velocity detecting fixed electrodes 25, 26
Vibrate in opposite phases. The charge amplifiers 66 and 67 convert these capacitance vibrations into voltage vibrations. The differential amplifier 68 differentially amplifies the signals of opposite phases from the charge amplifiers 66 and 67, approximately doubles the level (amplitude) of the signals, and generates a differentially amplified signal in which noise is canceled. Then, the differential amplifier 68 outputs the differential amplified signal to the synchronous detection circuit 56. The synchronous detection circuit 56 synchronizes with the synchronous signal in phase with the drive pulse signal,
A differential amplified signal provided by the differential amplifier 68, that is, a signal (voltage) corresponding to the torsional rotational vibration of the detection vibrator 12, is detected, and an angular velocity signal is output. The amplitude (signal level) of this angular velocity signal corresponds to the magnitude of the added angular velocity, and the applied angular velocity is detected by the same angular velocity signal.

As described in detail above, according to the present embodiment, the following effects can be obtained. (1) In the present embodiment, the first driving vibrator 16 and the second driving vibrator 17 are vibrated in the x direction in opposite phases to each other. That is, the first driving vibrator 16 and the second driving vibrator 17 are made to have a stable tuning fork vibration in the x direction.
The vibration has a high energy consumption rate. Then, from the first drive oscillator 16 and the second drive oscillator 17, for example, the drive-side oscillator 13, the stress relaxation frame 11, and the detection oscillator 12
Can be substantially canceled as a whole.

In this embodiment, the first driving vibrator 1
The sixth driving vibrator 17 and the second driving vibrator 17 vibrate in a coupled manner with the driving common-mode countermeasure spring 45 interposed therebetween. Therefore, it is possible to eliminate the vibration modes having the same phase as each other, for example, when the first driving vibrator 16 and the second driving vibrator 17 are separately provided. Therefore, even in an environment where there is a lot of vibration such as when the vehicle is mounted on a vehicle, the first driving oscillator 16 and the second driving oscillator 17 can be operated stably.

Further, in the present embodiment, the torsional rotational vibrations of the detection vibrator 12 and the drive-side vibrator 13 having opposite phases based on the angular velocity are caused by the first driving springs 41 and 42 and the second driving spring 43. , 44, the vibrations of the detection springs 33, 34 provided separately from the first and second driving vibrators 16, 17 and the detecting vibrator 12, and the driving vibrator 13, for example. Mechanical coupling etc. can be suppressed.

Further, in the present embodiment, the first and second driving vibrators 16 and 1 are caused by, for example, manufacturing variations.
When the vibrators 7 are driven to vibrate obliquely with respect to the x direction in opposite phases to each other, it is possible to avoid that this oblique vibration induces torsional rotational vibration with respect to the detecting vibrator 12 and the driving vibrator 13. it can.

On the other hand, the first and second driving vibrators 16 and 17 are applied, for example, by applying acceleration or the like applied in a predetermined direction.
Are also in phase with each other and are obliquely driven in a predetermined direction, the detection vibrator 12 and the drive-side vibrator 13 are formed in a substantially octagonal frame shape. Inducing torsional rotational vibration with respect to the driving-side vibrator 13 can be avoided.

Further, in the present embodiment, the detection oscillator 12
The detection vibrator 12 and the drive-side vibrator 13 were driven to vibrate in opposite phases to substantially cancel each torsional rotational vibration of the drive-side vibrator 13. Therefore, the torsional rotational vibrations of the detection vibrator 12 and the drive-side vibrator 13 related to the detection can be suppressed from propagating to the silicon substrate 10.

On the other hand, in the present embodiment, the stress relaxation frame 1
1, the detection vibrator 12 is disposed on the outer peripheral side thereof, and the drive side vibrator 13 and the first and second drive vibrators 16 and 17 are disposed on the point O side. In this embodiment, these connections are made with each connecting portion with the fulcrum as a fulcrum. Therefore, the weight of the floating supported structure is approximately 2
With this arrangement, the supporting strength required for the detection springs 33 and 34, for example, the cross-sectional area of the detection springs 33 and 34 can be reduced, and the size of the angular velocity sensor can be reduced.

By realizing the above operations simultaneously,
It is possible to provide an angular velocity sensor that has high accuracy and can be downsized. (2) In the present embodiment, the stress relaxation frame 11 and the detection spring 3
The connection portions with the reference numerals 3 and 34 are set at the positions of immovable portions (nodes) of torsional rotational vibrations having opposite phases around the z-axis around the point O of the detection vibrator 12 and the drive-side vibrator 13. . Therefore, for example, these detection vibrators 12 caused by unexpected vibration due to stress due to manufacturing variations, thermal expansion of the substrate, or the like.
And the driving-side vibrator 13 (the first and second driving vibrators 16,
17) The mechanical coupling can be extremely reduced. And, even in an environment where there is a lot of vibration, for example, when the vehicle is mounted on a vehicle, the accuracy of detecting the angular velocity can be improved.

(3) In the present embodiment, it is possible to reduce the transmission of the stress from the silicon substrate 10 due to, for example, an external temperature change or the application of an external force to the detection vibrator 12 (sensor).

(4) In this embodiment, the stress relaxation frame 11 can be rotated around the z-axis passing through the point O via the substrate stress relaxation springs 31 and 32 with respect to the silicon substrate 10 (floating body anchors a11 and a12). To support. Therefore, the detecting vibrator 12 having the stress relaxation frame 11 as a stationary part (node)
In addition, the resonance frequency of the torsional rotational vibration of the driving-side vibrator 13 having a phase opposite to that of the driving-side vibrator 13 is shifted from the resonance frequency at the time of driving, so that the response of the angular velocity sensor can be secured.

(5) In the present embodiment, the substrate stress relaxation springs 31, 32, the detection springs 33, 34, 38, the first drive springs 41, 42, the second drive springs 43, 44, and the drive common-mode countermeasure springs. 45 were all formed in a shape extending in the x or y direction and a combination thereof. Therefore, for example, semiconductor process processing by lithography can be suitably performed.

(Second Embodiment) Hereinafter, a second embodiment of the angular velocity sensor according to the present invention will be described with reference to FIG. The angular velocity sensor according to the second embodiment has a configuration in which the shape of the angular velocity sensor according to the first embodiment is mainly changed, and its operation mode is substantially equivalent to that of the first embodiment.

As shown in FIG. 6, the silicon substrate 10
A stress relaxation frame 71 made of conductive polysilicon having a shape different from that of the first embodiment, a detection vibrator 72, and a driving vibrator 7
3, a first driving vibrator 74, a second driving vibrator 75, a first driving force applying fixed electrode 76, a second driving force applying fixed electrode 77,
The first drive displacement detection fixed electrode 78, the second drive displacement detection fixed electrode 79, the first angular velocity detection fixed electrode 80, the second angular velocity detection fixed electrode 81, the floating body anchor a21, and the first auxiliary fixed electrode of conductive polysilicon 82 and a second auxiliary fixed electrode 83 are provided. The first and second auxiliary fixed electrodes 82 and 83 are joined to the silicon substrate 10. Incidentally, the floating body anchor a10 and the detecting spring (the detecting spring 38) for supporting the driving-side vibrator on the floating body anchor a10 are omitted in the present embodiment. It is similar to the first embodiment that it is provided substantially symmetrically on the xy plane.

The stress relaxation frame 71 is formed in a substantially octagonal frame shape, and its center on the xy plane substantially coincides with the point O. The stress relaxation frame 71 is connected to the floating body anchor a21 at each corner via a substrate stress relaxation spring 86 made of conductive polysilicon.

Each of the substrate stress relieving springs 86 is formed to bend substantially along the outer wall surface of the stress relieving frame 71 on the xy plane, and the bending directions of the adjacent substrate stress relieving springs 86 are alternated. Others have substantially the same shape. These substrate stress relaxation springs 86 are xy
It is formed to have high flexibility in the direction, so that the stress from the silicon substrate 10 due to, for example, an external temperature change or application of an external force is reduced from being transmitted to the sensor side.

The detecting vibrator 72 is provided with the detecting vibrator 1
2 are formed and arranged in accordance with 2. This detection oscillator 72
A direction obtained by rotating the x direction passing through point O of
On one side and the other side (referred to as the “xy direction”) and on the other side (upper right side and lower left side in FIG. 6), cutout portions 72a cut out from the inner wall surface to the outer wall surface are formed substantially along the same direction. I have. Then, the detection vibrator 72 is connected to the stress relaxation frame 71 and the driving-side vibrator 73 via a conductive polysilicon detecting spring 87 extending inward in the xy direction from each notch 72a.
It is continuous. One side and the other side (the upper left side and the lower right side in FIG. 6) in which the y direction passing through the point O of the detection vibrator 72 is rotated by approximately 45 degrees (hereinafter referred to as “−xy direction”).
Are formed with cutout portions 72b which are cut out from the inner wall surface to the outer wall surface side substantially along the same direction. The detecting vibrator 72 is connected to the stress relieving frame 71 and the driving vibrator 73 via a conductive polysilicon detecting spring 88 extending inward in the -xy direction from each notch 72b.

The detection springs 87 and 88 are continuous with the stress relieving frame 71 at an intermediate portion between adjacent corners of the stress relieving frame 71. The connection portions of the detection springs 87 and 88 to the stress relaxation frame 71 are torsional rotational vibrations having opposite phases around the z-axis around the point O of the detection vibrator 72 and the drive-side vibrator 73. This is the same as that of the first embodiment.

Also in this embodiment, detection springs 87 and 88 for supporting the detection vibrator 72 and the driving vibrator 73 are provided.
Are arranged so as to extend in the cross direction (the xy direction passing through the point O, the -xy direction), so that the postures of the detection vibrator 72 and the drive-side vibrator 73 are maintained parallel to the silicon substrate 10. . These detection springs 87 and 88 are
Since the flexure is formed to be high in the rotation direction about the z-axis about the point O, the torsional rotation of the detection vibrator 72 and the driving-side vibrator 73 around the z-axis about the point O is easy. It has become.

The drive-side vibrator 73 is formed in a substantially cross-shaped frame, and is arranged according to the drive-side vibrator 13. The drive-side vibrator 73 is connected to the detection springs 87 and 88 (stress relaxation frames 71) at corners on the base end side.

On the one side and the other side in the y direction passing through the point O of the driving side vibrator 73, there are formed projections 73a projecting substantially toward the point O in the same direction. The first
The driving vibrator 74 is arranged according to the first driving vibrator 16. The first driving vibrator 74 is formed in a substantially stepped frame narrowed to one side in the x direction (the right side in FIG. 6) via each step 74a on one side in the y direction and the other side.
The first driving vibrator 74 is located on the outer side in the x direction (the right side in FIG. 6).
Is connected to the driving-side vibrator 73 via a first driving spring 91 made of conductive polysilicon provided between the outer wall surface and the opposing inner wall surface of the driving-side vibrator 73.
Further, the first driving vibrator 74 is provided on the outer wall surface on the center side by y.
On the one side and the other side in the direction, the driving side vibrator 73 is connected to the driving side vibrator 73 via a first driving spring 92 made of conductive polysilicon provided between the opposing projections 73a of the driving side vibrator 73. ing.

The first driving springs 91 and 92 are bent and formed so as to extend in the y-direction so as to increase flexibility only in the x-direction. The short width side of the first driving vibrator 74 is divided into a base end side and a tip end side in the x direction, and the same driving force applying movable electrode 16b as the driving force applying movable electrode 16b is applied to the base end side frame. A movable electrode 74b is formed, and the first and second driving force applying fixed electrodes 76 and 77 are respectively opposed to the driving force applying movable electrode 74b. Therefore, the driving force applying movable electrode 74b is moved between the first and second driving force applying fixed electrodes 76, 77 by the driving signal supplied to the first and second driving force applying fixed electrodes 76, 77. Is periodically fluctuated, causing the first driving vibrator 74 to generate vibration in the x direction.

The drive force applying movable electrode 74b is provided on the short end side frame in the x direction of the first drive vibrator 74.
An auxiliary movable electrode 74c having the same shape as that of the auxiliary movable electrode 74c is formed. The auxiliary movable electrode 74c, together with the first and second driving force applying fixed electrodes 76 and 77, is connected to the first and second driving force applying fixed electrodes 76 and 77.
The electrostatic attraction between the first and second auxiliary fixed electrodes 82 and 83 is periodically changed by the drive signal supplied to the auxiliary fixed electrodes 82 and 83, and the x direction of the first driving vibrator 74 is changed. Assist the vibration of.

Further, a drive displacement detection movable electrode 74d similar to the drive displacement detection movable electrode 16c is formed in the long width side frame of the first drive vibrator 74. , The first and second driving displacement detection fixed electrodes 78 and 79 are disposed to face each other.
Therefore, the drive displacement detection movable electrode 74d changes the capacitance between the first and second drive displacement detection fixed electrodes 78 and 79 by the vibration of the first drive vibrator 74 in the x direction.

On the other hand, the second driving vibrator 75 is arranged according to the second driving vibrator 17. Similarly, the second drive vibrator 75 includes a step 75 on one side and the other side in the y direction.
It is formed in a substantially step-shaped frame that is reduced in width in the x direction on the other side (the left side in FIG. 6) via a. This second drive vibrator 7
Reference numeral 5 denotes the same driving via a second driving spring 93 made of conductive polysilicon provided between the outer wall surface on the outer side in the x direction (left side in FIG. 6) and the inner wall surface facing the driving-side vibrator 73. It is continuous with the side vibrator 73. The second drive vibrator 75 is made of conductive polysilicon provided between the opposing protrusions 73 a of the drive-side vibrator 73 on one side and the other side of the outer wall on the center side in the y direction. Second drive spring 9
4 and connected to the same drive side vibrator 73.

The second driving springs 93 and 94 are bent and formed so as to extend in the y direction so as to increase flexibility only in the x direction. The second driving vibrator 75 also has a driving force applying movable electrode 75b similar to the driving force applying movable electrode 74b. This driving force applying movable electrode 7
5b is also the first and second driving force applying fixed electrodes 76, 7
7, the electrostatic attraction between the first and second driving force applying fixed electrodes 76 and 77 is periodically changed, and the second driving vibrator 75 is caused to vibrate in the x direction. generate.

The second driving vibrator 75 also has an auxiliary movable electrode 75c similar to the auxiliary movable electrode 74c. The auxiliary movable electrode 75c is also driven by a drive signal supplied to the first and second auxiliary fixed electrodes 82 and 83 together with the first and second driving force applying fixed electrodes 76 and 77. The electrostatic attraction between the second driving vibrator 75 and the second driving vibrator 75 varies periodically.
In the x direction.

Further, the second drive vibrator 75 is also provided with a drive displacement detection movable electrode 75d similar to the drive displacement detection movable electrode 74d. The drive displacement detection movable electrode 75d also varies the capacitance between the first and second drive displacement detection fixed electrodes 78 and 79 by the vibration of the second drive vibrator 75 in the x direction.

The first and second driving vibrators 74, 74
75 is arranged substantially symmetrically with respect to the y-axis passing through the point O, so that the first and second driving vibrators 7 are arranged similarly to the first embodiment.
Nos. 4, 75 are resonance tuning fork vibrations stable in the x direction, and have high energy consumption rates.

Here, the first and second driving vibrators 7
4, 75 opposing wall surfaces are connected via a drive common-mode countermeasure spring 95 as a conductive spring of conductive polysilicon. The drive in-phase countermeasure spring 95 is also bent and formed so as to extend from the center side to the outside in the y direction so as to increase the flexibility only in the x direction. The first and second driving vibrators 7
4, 75 are coupled and vibrated by the driving common-mode countermeasure spring 95, so that the in-phase vibration mode is eliminated. Therefore, even in an environment where there is a lot of vibration such as when mounted on a vehicle, the first and second driving vibrators 74 and 75 can be used.
Operates stably.

When an angular velocity about the z-axis passing through the point O is applied while the first and second driving vibrators 74 and 75 are resonating in a tuning fork vibration in the x direction, the first and second driving vibrators 74 and 75 are driven. , 75 perform relatively opposite-phase elliptical vibrations having mutually opposite y-direction vibration components by the Coriolis force based on the angular velocity. At this time, each connection between the stress relaxation frame 71 and the detection springs 87 and 88 is connected to the detection vibrator 72.
In addition, since it is set at the position of the non-moving part (node) of the torsional rotational vibration having the opposite phase around the z-axis around the point O of the drive-side vibrator 73, the same detected vibration is performed as in the first embodiment. The element 72 and the drive-side vibrator 73 perform torsional rotational vibrations having phases opposite to each other.

The torsional rotational vibration about the z axis passing through the point O of the detection vibrator 72 is caused by the first and second angular velocity detection fixed electrodes 80 and 81 and the detection vibrator 72 (angular velocity detection movable electrode 3).
7) is detected as a vibration of the capacitance between them. The applied angular velocity about the z-axis is detected based on the state of the torsional rotational vibration about the z-axis about the point O of the detection vibrator 72.

The electrical configuration relating to the angular velocity detection of the angular velocity sensor according to the second embodiment is such that the first and second auxiliary fixed electrodes 82 and 83 are driven together with the first and second driving force applying fixed electrodes 76 and 77. The drive signals A,
Except that B is supplied, it is the same as the first embodiment, and a description thereof will be omitted.

As described in detail above, according to the present embodiment, the following effects can be obtained in addition to the effects (1) to (4) of the first embodiment. (1) In the present embodiment, the first and second driving vibrators 74,
The auxiliary movable electrodes 74c and 75c and the opposing first and second auxiliary fixed electrodes 82 and 83 are provided to assist the vibration driving force of 75. Therefore, the vibration driving force of the first and second driving vibrators 74 and 75 can be suitably secured.

The embodiment of the present invention is not limited to the above embodiment, but may be modified as follows. In each of the above embodiments, the stress relaxation frames 11 and 71 and the detection oscillators 12 and 72 are formed in a substantially octagonal frame shape. It may be a polygonal frame.

In each of the above embodiments, the drive-side vibrators 13 and 73 are formed in a substantially octagonal frame shape or a substantially cross-shaped frame shape. May be another polygonal frame shape.

The first embodiment employed in each of the above embodiments.
The shapes of the driving vibrators 16 and 74 and the second driving vibrators 17 and 75 are merely examples, and may be other shapes. For example, the first driving vibrators 16 and 74 and the second driving vibrators 17 and 75 are formed into a substantially polygonal, substantially circular, substantially semicircular or other frame shape which is substantially symmetric with respect to the y-axis passing through the point O. It may be formed. Further, it may be formed not in a frame shape but in a skeleton shape.

The first embodiment employed in each of the above embodiments
The drive structure (drive circuit unit) of the drive vibrators 16 and 74 and the second drive vibrators 17 and 75 in the x direction is an example, and another structure may be adopted. For example, the first driving vibrator 1
A drive signal (voltage) is applied to only the first and second vibrators 16 and 74 to vibrate in the x direction, and the second vibrators 17 and 75 vibrate in opposite directions in the x direction by resonance. It may be driven.

The detection oscillator 1 in each of the above embodiments.
The positional relationship between the second and second drive units 72 and the driving-side vibrators 13 and 73 may be opposite to each other. -Instead of the silicon substrate 10 in each of the above embodiments,
For example, polycrystalline, single crystalline, or amorphous Si, Ge, Si
The substrate may be formed of C, SixGe1-x, or SixGeyC1-xy.

Next, technical ideas other than the claims that can be grasped from the above embodiments will be described below together with their effects. (A) The first and second driving vibrators arranged substantially symmetrically with respect to the point O on the xy plane, and formed into any one of a substantially circular shape and a substantially polygonal shape which is substantially symmetrical with respect to the point O. And a detection vibrator surrounding the first driving vibrator and the second driving vibrator, and one of a substantially circular frame and a substantially polygonal frame substantially symmetrical with respect to a point O to form the detection vibrator. The first driving vibrator and the second driving vibrator can be respectively vibrated in the x direction with respect to the detection vibrator so as to be substantially symmetric with respect to the surrounding detection side vibrator and the y direction passing through the point O. A first driving spring and a second driving spring floatingly supported;
The detection vibrator and the detection-side vibrator are torsionally rotated in opposite phases around a z-axis passing through a point O with respect to a connection portion between the detection vibrator and the substrate disposed between the detection-side vibrators. A plurality of detection springs floatingly supported as possible, and a coupling spring interposed between the first driving vibrator and the second driving vibrator to couple and vibrate the first driving vibrator and the second driving vibrator. ,
A driving means for driving the first driving vibrator and the second driving vibrator in opposite directions to vibrate in the x direction; and a detecting means for detecting a torsional rotational vibration around the z-axis passing through a point O of the detection vibrator. An angular velocity sensor characterized in that: According to the same configuration,
The same effect as the first aspect can be obtained.

[0098]

As described in detail above, according to the first aspect of the present invention, it is possible to provide an angular velocity sensor that has high accuracy and can be downsized.

According to the second aspect of the present invention, the accuracy of detecting the angular velocity can be improved. According to the third aspect of the present invention, it is possible to reduce the transmission of the stress from the substrate due to the application of an external temperature change, external force, or the like to the detection vibrator (sensor) side.

Further, the resonance frequency of the torsional rotational vibration of the driving-side vibrator and the detection vibrator connected to the substrate via the stress relaxation frame and the stress relaxation spring is shifted from the resonance frequency at the time of driving, and the angular velocity is changed. The response of the sensor can be ensured.

[Brief description of the drawings]

FIG. 1 is a plan view showing a first embodiment of an angular velocity sensor according to the present invention.

FIG. 2 is an exemplary block diagram showing the electrical configuration of the embodiment.

FIG. 3 is a time chart showing driving signals applied to first and second driving force application fixed electrodes of the embodiment.

FIG. 4 is a plan view showing driving vibration of the embodiment.

FIG. 5 is an exemplary plan view showing the detection vibration of the embodiment;

FIG. 6 is a plan view showing a second embodiment of the angular velocity sensor according to the present invention.

[Explanation of symbols]

 11, 71 Stress relaxation frame 12, 72 Detection vibrator 13, 73 Driving vibrator 16, 74 First driving vibrator 17, 75 Second driving vibrator 33, 34, 87, 88 Detection spring 41, 42, 91 , 92 First drive spring 43, 44, 93, 94 Second drive spring 45, 95 Drive common-phase countermeasure spring as combined spring

Claims (3)

[Claims] 1. A first driving vibrator and a second driving vibrator arranged substantially symmetrically with respect to a point O on an xy plane, and one of a substantially circular shape and a substantially polygonal shape substantially symmetrical with respect to the point O And a driving-side vibrator surrounding the first driving vibrator and the second driving vibrator; and a frame formed in one of a substantially circular and substantially polygonal shape substantially symmetric with respect to a point O. A first vibrator and a second vibrator in the x direction with respect to the driving vibrator so as to be substantially symmetric with respect to the y direction passing through the point O; A first driving spring and a second driving spring that are supported so as to be capable of vibrating and floating, and a connection between the driving-side vibrator and the detection vibrator and a substrate disposed between the driving-side vibrator and the detection vibrator. Torsional rotational vibrations in opposite phases around the z axis passing through point O to the part A plurality of detection springs floatingly supported, and a coupling spring interposed between the first driving vibrator and the second driving vibrator to couple and vibrate the first driving vibrator and the second driving vibrator; A driving means for oscillatingly driving the first driving vibrator and the second driving vibrator in the x direction in opposite phases; and a detecting means for detecting torsional rotational vibration around the z-axis passing through a point O of the detection vibrator. An angular velocity sensor comprising: 2. The angular velocity sensor according to claim 1, wherein the connection portion with the substrate has a torsional rotational vibration in which the driving-side vibrator and the detection vibrator are in opposite phases around the z-axis passing through a point O. An angular velocity sensor substantially coincident with a node at the time of performing. 3. The angular velocity sensor according to claim 1, wherein the drive-side vibrator and the detection vibrator are formed in any one of a substantially circular shape and a substantially polygonal shape that is substantially symmetric with respect to a point O. A stress relaxation frame disposed therebetween; and a stress relaxation spring for floatingly supporting the stress relaxation frame on the xy plane with respect to the substrate so that the stress relaxation frame can be vibrated. An angular velocity sensor connected to a substrate via a relaxation spring.