JP2002148048A - Angular speed detecting element - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enhance angular speed detection accuracy. SOLUTION: A weight 3 is disposed oppositely to a base 2 through an interval. The weight 3 is supported displaceably by a fixed part 5 through four beams 4. The four beams 4 are arranged such that the angle defined by beams 4a and 4b, and the angle defined by beams 4c and 4d become larger than the angle defined by beams 4a and 4d, and the angle defined by beams 4b and 4c. The weight 3 performs horizontal rotary oscillation about the Z-axis along the surface of the base 2 through a drive means. When the weight 3 rotates about the Y-axis under that oscillatory state, the weight 3 performs rotary oscillation about the X-axis by Coliolis force. Angular speed of rotation about the Y-axis can be detected by detecting that oscillatory state through an electrode 7 for detecting angular speed about the Y-axis. Resonance frequency of horizontal rotary oscillation of the weight 3 and resonance frequency of detected oscillation by Coliolis force can be lowered easily such that they are insusceptible to adverse effect of unnecessary oscillation as compared with resonance frequency of the unnecessary oscillation.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vibration type angular velocity detecting element.

[0002]

2. Description of the Related Art FIG. 7 is a perspective view showing an example of an angular velocity detecting element. The angular velocity detecting element 1 shown in FIG.
Is a two-axis detection type, and includes a base 2 and a weight 3
, Four beams 4 (4a, 4b, 4c, 4d), a fixed portion 5 (5a, 5b, 5c, 5d), an X-axis angular velocity detection electrode 6 (6a, 6b), and a Y-axis. It comprises an angular velocity detecting electrode 7 (7a, 7b) and a driving means (not shown).

The angular velocity detecting element 1 is formed, for example, by bonding a semiconductor substrate to the upper side of the base (for example, a glass substrate) 2 by an anodic bonding method or the like, and processing the semiconductor substrate by a micromachining technique to form the weight portion 3. It is manufactured by shaping the beam 4, the fixing portion 5, and the like. Generally, a lid member (for example, a glass substrate) is disposed above the weight portion 3 and the like, and a vacuum space formed inside a laminate of the base 2, the semiconductor substrate, and the lid member is provided. The weight portion 3, the beam 4, the fixing portion 5 and the like are housed and sealed.

[0004] In the angular velocity detecting element 1, as shown in FIG. 7, a weight 3 is disposed above the base 2 so as to face the surface of the base 2 with a space therebetween. This weight 3
The fixed portions 5a, 5b, 5c, 5d are respectively fixedly arranged on the base 2 so as to surround the beam.
a, 4b, 4c, and 4d displaceably supported by the fixing portions 5a, 5b, 5c, and 5d. Each of the beams 4a, 4b, 4c, and 4d is formed so as to extend from the surface of the base 2 at an interval and in parallel with the surface of the base 2. Each of the beams 4a, 4b, 4c, 4d is
Each of the beams is arranged so that the angle formed between the beams adjacent to each other in the direction orbiting around the weight portion 3 is 90 degrees.

FIG. 8 is a plan view showing the weight 3, beam 4, and fixing portion 5 from above shown in FIG. On the surface of the base 2, as shown in FIG. 7, the X-axis angular velocity detecting electrodes 6 (6 a , 6b) are formed. Further, on the surface of the base 2, the electrodes 7 for detecting the angular velocity around the Y-axis 7 as shown in FIG.
(7a, 7b) are formed. The four electrodes, ie, the X-axis angular velocity detection electrodes 6a and 6b and the Y-axis angular velocity detection electrodes 7a and 7b, are arranged with an insulating space therebetween.

The angular velocity detecting element 1 includes the weight 3
A drive means (not shown) for horizontally rotating and vibrating the base 2 along the surface of the base 2 around the Z axis shown in FIG. 7 is provided. FIG. 9A shows the weight 3 and the beam 4 when the weight 3 is vibrating horizontally by the driving means.
Is shown by a schematic diagram viewed from above shown in FIG.

As described above, when the weight portion 3 is vibrating in the horizontal rotation, as shown in FIG. 7 which is orthogonal to the Z axis which is the center axis of the horizontal rotation vibration and along the surface of the base 2. When it rotates around the X axis shown, the rotation around the X axis
A Coriolis force is generated in the direction α that rotates about the Y axis shown in FIG. 7 that is orthogonal to both the Z axis and the X axis. This Coriolis force acts on the weight 3, the beam 4 bends as shown in FIG. 9B, and the weight 3 rotates and vibrates around the Y axis. That is, the weight portion 3 vibrates so that the region A and the region C shown in FIG. Due to the rotational vibration of the weight 3 caused by the rotation about the X axis, the capacitance between the weight 3 and the X-axis angular velocity detecting electrodes 6a and 6b greatly changes. This change in capacitance is detected from the electrodes 6a and 6b for detecting angular velocities around the X-axis.
The magnitude of the angular velocity of rotation around the axis can be detected.

Further, when the weight portion 3 is rotated about the Y axis shown in FIG. 7 while the weight portion 3 is vibrating horizontally, the X axis shown in FIG. 7 is rotated by the rotation about the Y axis. A Coriolis force in the direction β rotating around the center is generated. This Coriolis force acts on the weight 3, and the weight 3 oscillates around the X axis so that the areas B and D shown in FIG. 8 alternately approach the base 2. As a result, the capacitance between the weight portion 3 and the electrodes 7a and 7b for detecting the angular velocity around the Y-axis greatly changes. This change in capacitance can be detected from the electrodes 7a and 7b for detecting the angular velocity around the Y axis, and the magnitude of the angular velocity of rotation around the Y axis can be detected.

As described above, the angular velocity detecting element having the configuration shown in FIG. 7 has a configuration capable of detecting the angular velocity of rotation about the X axis and the angular velocity of rotation about the Y axis.

[0010]

By the way, in the angular velocity detecting element 1 having the above-mentioned structure, the weight portion 3 has the Z
Horizontal rotation vibration around the axis (hereinafter referred to as driving vibration) and X
Not only rotational vibration (hereinafter referred to as detection vibration) due to Coriolis force caused by rotation about the axis or rotation about the Y axis, but also various other unnecessary vibrations are generated. For example, as the unnecessary vibration, as shown in FIG.
Z-axis vibration that vibrates in the axial direction, Y-axis horizontal vibration in which the weight 3 vibrates in the Y-axis direction along the surface of the base 2, and X-axis vibration in which the weight 3 moves along the surface of the base 2 X-axis horizontal vibration, etc.

In order to accurately detect the angular velocity of rotation about the X-axis and the angular velocity of rotation about the Y-axis, both the resonance frequency of the driving vibration of the weight 3 and the resonance frequency of the detected vibration are set as described above. It is desirable that the resonance frequency is lower than the resonance frequency of the vibration mode of the unnecessary vibration by, for example, 2 to 3 kHz or more. In other words, the resonance frequency of the unnecessary vibration is preferably higher than the resonance frequency of both the driving vibration and the detection vibration by, for example, 2 to 3 kHz or more.

This is due to the following reasons. That is, the signals output from the electrode 6 for detecting the angular velocity around the X-axis and the electrode 7 for detecting the angular velocity around the Y-axis include a signal component for detecting the angular velocity corresponding to the detected vibration of the weight 3,
A noise component or the like corresponding to the unnecessary vibration is included. When the resonance frequency of the driving vibration and the resonance frequency of the detection vibration are substantially equal to or higher than the resonance frequency of the unnecessary vibration, the X-axis angular velocity detecting electrode 6 and the Y-axis angular velocity detecting electrode 7 It is difficult to remove a noise component caused by the unnecessary vibration from the output signal.

On the other hand, when the resonance frequency of the driving vibration and the resonance frequency of the detection vibration are both lower than the resonance frequency of the unnecessary vibration by, for example, 2 to 3 kHz or more (the resonance frequency of the unnecessary vibration is lower than the driving frequency of the driving vibration). In the case where the frequency is higher than the resonance frequency of the vibration and the resonance frequency of the detected vibration by 2 to 3 kHz or more), the difference between the frequencies is used to make the electrode 6 for detecting the angular velocity around the X axis and the electrode 7 for detecting the angular velocity around the Y axis. It is easy to remove the noise component caused by the unnecessary vibration from the output signal, and the accuracy of the angular velocity detection can be improved. From this, as described above, the resonance frequency of the drive vibration and the resonance frequency of the detection vibration are both lower than the resonance frequency of the unnecessary vibration by, for example, 2 to 3 kHz.
It is desirable that it is lower than this.

However, in the angular velocity detecting element 1 having the above configuration, it is very difficult to make both the resonance frequency of the driving vibration and the resonance frequency of the detected vibration lower than the resonance frequency of the unnecessary vibration so as not to be adversely affected by the unnecessary vibration. Difficult.

This can be seen from the following experiments by the inventor. The inventor changes one of the length L of the beam 4, the width H of the beam 4, and the thickness of the beam 4 shown in FIG. 8 as a parameter, and the other conditions are the same.
The resonance frequency of the drive vibration and the resonance frequency of the detection vibration,
From the plurality of unnecessary vibrations, how the resonance frequency of the vibration in the Z-axis direction, which most adversely affects the detection of the angular velocity, changes was examined by a finite element method (simulation).

The experimental results are shown in the graphs of FIGS. 10 (a) to 10 (c). FIG. 10A shows a case where the thickness of the beam is changed, FIG. 10B shows a case where the width H of the beam is changed, and FIG. 10A to 10C, the solid line A represents the change in the resonance frequency of the detected vibration, and the dotted line B
Represents the resonance frequency change of unnecessary vibration (vibration in the Z-axis direction),
A broken line C indicates a change in the resonance frequency of the driving vibration.

As shown in the graphs of FIGS. 10A to 10C, even if the thickness of the beam 4, the width H of the beam 4, and the length L of the beam 4 are varied, the resonance frequency of the unnecessary vibration is changed. Also, it was impossible to lower the resonance frequencies of both the driving vibration and the detection vibration.

As is clear from the above experimental results, FIG.
In the angular velocity detecting element 1 having the form shown in (1), it is very difficult to make both the resonance frequency of the drive vibration and the resonance frequency of the detected vibration lower than the resonance frequency of the unnecessary vibration.
For this reason, there is a problem that the angular velocity cannot be detected with high accuracy due to noise components caused by unnecessary vibration included in the output signals of the X-axis angular velocity detection electrode 6 and the Y-axis angular velocity detection electrode 7. .

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and an object of the present invention is to make both the resonance frequency of the drive vibration of the weight and the resonance frequency of the detection vibration lower than the resonance frequency of the unnecessary vibration. Accordingly, an object of the present invention is to provide an angular velocity detecting element capable of improving the accuracy of angular velocity detection.

[0020]

In order to achieve the above-mentioned object, the present invention has the following structure to solve the above-mentioned problem. In other words, the first invention provides a base, a weight portion opposed to the surface of the base with an interval therebetween, four beams for supporting the weight portion in a displaceable manner, A driving means for horizontally rotating and oscillating the weight portion along the surface of the base with the Z-axis perpendicular to the surface and the weight portion as a central axis, wherein the four beams are , Respectively, are formed to extend in the direction away from the weight portion, and each of these beams,
Each of the beams adjacent to each other in the direction of orbiting the periphery of the weight portion is arranged to have an angle formed with one side larger than the angle formed with the other side, and the weight by the driving means is The above-described object is achieved by a configuration in which both the resonance frequency of the drive vibration of the unit and the resonance frequency of the detection vibration of the weight portion caused by the Coriolis force are lower than the resonance frequencies of the vibration modes other than the drive vibration and the detection vibration. Means.

According to a second aspect of the present invention, there is provided the configuration of the first aspect of the present invention, wherein the weight portion is caused by the rotation about the Y axis parallel to the surface of the base as the center axis due to the arrangement of the four beams. When a Coriolis force is generated, a rotational vibration is generated about the X axis orthogonal to the two axes of the Y axis and the Z axis, and the rotational vibration caused by the rotation of the weight portion around the Y axis. Is provided by using a Y-axis angular velocity detecting unit for detecting the angular velocity using a capacitance.

According to a third aspect of the present invention, there is provided the configuration of the second aspect of the present invention, wherein the weight section is provided with an X-axis detection vibration section that vibrates by Coriolis force caused by rotation about the X axis. In addition, an X-axis rotation angular velocity detection unit that detects vibration caused by the Coriolis force of the X-axis rotation detection vibration unit by using capacitance is provided.

According to a fourth aspect of the present invention, there is provided the structure of the third aspect of the invention, wherein the weight portion has a frame shape, and the weight portion is formed inside the frame to extend from the frame in the Y-axis direction. Connecting beams,
An internal weight portion formed by a detection vibrator for detecting an angular velocity around the X-axis supported by the connecting beam and vibrating by a Coriolis force caused by rotation about the X-axis is formed on a surface of the base. An electrode for detecting a Y-axis angular velocity, which is a Y-axis angular velocity detecting unit, is formed at a part facing the frame, and an X-axis angular velocity, which is an X-axis angular velocity detecting unit, is formed at a part facing the internal weight. It is characterized in that a detection electrode is formed.

According to a fifth aspect of the present invention, there is provided the configuration of any one of the first to fourth aspects of the invention, wherein each beam is spaced from the surface of the base and parallel to the surface of the base. It is configured to be elongated.

According to a sixth aspect of the present invention, there is provided the configuration according to any one of the first to fifth aspects, wherein the four beams form a set of two beams, and the two beams of the same set are formed by two beams. , Respectively, are arranged at positions symmetrical with respect to the center axis of the horizontal rotation of the weight portion.

In the invention having the above structure, each of the four beams has an angle formed with one side of one of two adjacent beams adjacent to each other in the direction of orbiting around the weight portion. Are formed so as to be larger. Due to such a peculiar arrangement of the beams, the weight portion is more likely to be moved by the Coriolis force due to the rotation about the Y axis than in the case of the conventional arrangement of the beams.
Rotational vibration about the axis is facilitated. Further, when a Coriolis force is generated due to the rotation around the X axis, the vibration of the weight portion due to the Coriolis force is suppressed by the specific arrangement of the beams.

With this configuration, the resonance frequency of the horizontal rotation vibration (drive vibration) around the Z axis of the weight portion and the rotation vibration (detection vibration) due to the Coriolis force caused by the rotation around the Y axis. Of the vibration modes other than the driving vibration and the detected vibration (that is, the resonance frequency of the unnecessary vibration) can be easily reduced. This makes it possible to improve the accuracy of detecting the angular velocity of rotation about the Y axis.

[0028]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a schematic perspective view showing main components of the angular velocity detecting element according to the first embodiment. FIG. 2 shows the weights and beams shown in FIG. 1 from above shown in FIG. The plan view seen is schematically shown. In the description of the first embodiment, the same components as those of the conventional example are denoted by the same reference numerals, and the description of the common portions will not be repeated.

The angular velocity detecting element 1 shown in the first embodiment is of a type for detecting the angular velocity of rotation about the Y axis shown in FIG. 1. The most characteristic feature of the first embodiment is that: As shown in FIGS. 1 and 2, each beam 4
(4a, 4b, 4c, 4d) each have an angle of less than 90 degrees with one of the two sides adjacent to each other in the direction of circling the weight portion 3 and form with the other side. That is, they are arranged so that the angle is larger than 90 degrees. In other words, each beam 4 (4a, 4b, 4
c, 4d) are arranged and formed such that the angle formed with the other side is larger than the angle formed with the other side of both sides adjacent to each other in the direction of circling the weight portion 3. That is.

As a specific example, for example, as shown in FIG. 2, the beams 4a and 4c are on the same straight line passing through the Z axis (that is, the central axis of the horizontal rotation vibration (drive vibration) of the weight 3). The beams 4b and 4 are disposed at symmetrical positions via the Z axis.
Similarly, d is disposed at a symmetrical position on the same straight line passing through the Z-axis via the Z-axis, and an acute angle formed by the straight line along the beams 4a and 4c and the straight line along the beams 4b and 4d. R1, R
3 (in other words, the angle R1 formed by the beam 4a and the beam 4b and the angle R3 formed by the beam 4c and the beam 4d) are set to 18 degrees,
The obtuse angles R2 and R4 between the straight line along the line 4c and the straight lines along the beams 4b and 4d (in other words, the angle R2 between the beam 4b and the beam 4c and the angle R4 between the beam 4d and the beam 4a) are 162 degrees. I do.

As described above, each beam 4a, 4b, 4c, 4d
Is arranged, the beam 4a and the beam 4b are close to each other, and the beam 4c and the beam 4d are close to each other. For this reason, in the first embodiment, the adjacent beams 4a
And a fixing portion 5 (5A) for supporting the beam 4b in common,
A fixed portion 5 (5B) for supporting the adjacent beams 4c and 4d in common is fixedly provided on the base 2.

In the first embodiment, similarly to the conventional example, a driving means (not shown) for causing the weight portion 3 to vibrate horizontally (drive vibration) about the Z axis as a center axis is provided. Is provided. When the weight unit 3 is driven and vibrated by the driving means and rotates about the Y axis shown in FIG. 1 as described above, Coriolis force is generated due to the rotation about the Y axis as described above. In the first embodiment, the weight 3
Is configured to be more susceptible to rotational vibration about the X axis as a center axis due to the Coriolis force than in the case where the angles formed by the adjacent beams 4 are all 90 degrees as in the conventional example. I have. On the other hand, when the Coriolis force is generated due to the rotation about the X axis, the weight 3 is rotated by the rotation about the X axis due to the arrangement of the beams 4 unique to the first embodiment. Vibration displacement caused by Coriolis force is suppressed.

In the first embodiment, as shown in FIG. 1, a weight on the surface of the base 2 whose distance from the base 2 is greatly changed by Coriolis force caused by the rotation about the Y axis. In the area corresponding to the portion of the section 3, the Y-axis angular velocity detecting electrodes 7 (7a, 7b), which are Y-axis angular velocity detecting sections, are provided.
Are formed. These electrodes 7 for detecting the angular velocity around the Y axis
A signal corresponding to the capacitance between the a and b and the weight portion 3 is detected from the electrodes 7a and 7b for detecting the angular velocity around the Y axis, and the angular velocity of rotation around the Y axis can be detected based on the detection signal. . In addition, the electrodes 7a and 7
“b” is disposed via an insulating space.

According to the first embodiment, each beam 4 is
Each of the weights 3 is arranged so that the angle formed with one side of the two sides adjacent to each other in the direction of orbiting around the weight 3 is larger than the angle formed with the other side. Drive vibration (horizontal rotation vibration about the Z axis)
And the resonance frequency of the detected vibration (the rotation vibration of the weight portion 3 due to the Coriolis force due to the rotation about the Y axis) is lower than the resonance frequency of the unnecessary vibration to such an extent that the unnecessary vibration is hardly adversely affected (for example, , 2-3 kHz or more).

This has been confirmed by experiments performed by the present inventors. In the experiment, the magnitude of the acute angle formed by the straight line along the beams 4a and 4c and the straight line along the beams 4b and 4d in the angular velocity detecting element 1 having the configuration shown in FIG. The resonance frequency of the driving vibration of the weight 3, the resonance frequency of the vibration detected by the weight 3,
The resonance frequency of the unnecessary vibration (the Z-axis direction vibration) was changed by a simulation. In this experiment, the diameter of the weight 3 was 1000
μm, the width of the beam 4 is 10 μm, and the length of the beam 4 is 1000
μm and the thickness of the beam 4 was set to 50 μm.

The experimental results are shown in the graph of FIG. The solid line A shown in FIG. 3 relates to the detected vibration of the weight 3, the solid line B relates to the unnecessary vibration of the weight 3, and the solid line C relates to the drive vibration of the weight 3. As shown in FIG. 3, for example, when the acute angle between the straight lines along the beams 4a and 4c and the straight lines along the beams 4b and 4d is 18 degrees and the obtuse angle is 162 degrees, 3 is 9.11 kHz, the resonance frequency of the drive vibration of the weight 3 (see the solid line C) is 7.39 kHz, whereas the resonance frequency of the unnecessary vibration (the solid line B) is 7.39 kHz. 1)
2.57 kHz, and the resonance frequency of the driving vibration of the weight 3 and the resonance frequency of the detected vibration are both lower than the resonance frequency of the unnecessary vibration by 2 kHz or more.

As shown in the above experimental results, the weight 3
The resonance frequency and the detection of the driving vibration of the weight 3 can be easily obtained by changing the position of the four beams 4 without changing the size of the beam 4, the width H, the length L, and the thickness of the beam 4. Both of the resonance frequencies of the vibration can be made lower than the resonance frequency of the unnecessary vibration to such an extent that the adverse effects of the unnecessary vibration are hardly affected.

In the experimental results shown in FIG.
In an angle region where the acute angle formed by the straight lines along the beams 4a and 4c and the straight lines along the beams 4b and 4d is greater than about 23 degrees and less than 90 degrees, the resonance frequency of the vibration detected by the weight 3 is The resonance frequency of the unnecessary vibration is almost the same or higher, but simply by changing at least one of the size of the weight portion 3, the width H of the beam 4, the beam length L, and the beam thickness, Even in the angle region larger than about 23 degrees and smaller than 90 degrees, the resonance frequency of the detected vibration can be made lower than the resonance frequency of the unnecessary vibration to such an extent that the adverse vibration is not adversely affected. Thus, the resonance frequency of the driving vibration of the weight portion 3 and the resonance frequency of the detected vibration can both be lower than the resonance frequency of the unnecessary vibration.

As described above, each of the beams 4 is disposed such that the angle between the beam 4 and one of the adjacent beams is larger than the angle between the beam 4 and the other beam, thereby forming the weight portion. The resonance frequency of the driving vibration and the resonance frequency of the detected vibration can easily be made lower than the resonance frequency of the unnecessary vibration so as not to be adversely affected by the unnecessary vibration. Angular velocity detection accuracy can be improved.

Conventionally, four beams 4
Are formed so as to extend in four directions, respectively, whereas in the first embodiment, four beams 4 are formed to extend from the weight 3 in two directions substantially opposite to each other. Since the angular velocity detecting element 1 can be made thinner than the conventional example, the angular velocity detecting element 1 can be made thinner.
Can be reduced in size.

Further, in the first embodiment, the above 4
The fixing portion 5 for supporting the beam 4 depends on the arrangement of the beam 4.
Need only be arranged at two places, and the pattern shape of the weight 3, the beam 4, the fixed part 5, and the like made of a semiconductor substrate is different from the conventional configuration in which the fixed parts 5 are scattered at four places. Is simplified, and the pattern formation on the semiconductor substrate is facilitated.

Hereinafter, a second embodiment will be described. In the description of the second embodiment, the same components as those of the first embodiment are denoted by the same reference numerals, and the overlapping description of the common portions will be omitted.

FIG. 4 is a schematic plan view showing an angular velocity detecting element according to the second embodiment. The angular velocity detecting element 1 shown in FIG. 4 is of a two-axis detection type. The characteristic point is that, in addition to the configuration similar to that of the first embodiment, the angular velocity of rotation about the X axis can also be detected. Is provided. That is, the angular velocity detecting element 1 shown in the second embodiment includes a base 2, a weight 3, and four beams 4 (4) as shown in the first embodiment.
a, 4b, 4c, 4d) and the fixing part 5 (5A, 5B)
An electrode 7 for detecting angular velocity around the Y-axis 7 (7a, 7b), and a driving electrode unit 13 (13a, 13b) as driving means;
Fixed portions 16 (16a, 16b), 17 (17a, 17
b), in addition to the X-axis angular velocity detecting electrode 6 (6a, 6b), which is an X-axis angular velocity detector,
The internal weight 11 (1
1a, 11b), and in the second embodiment, the drive vibration monitoring means 20 (20a, 20b, 2)
0c, 20d) and the fixing portion 23.

That is, also in the second embodiment, similarly to the first embodiment, the weight portion 3 is opposed to the surface of the base 2 with an interval therebetween.
Is supported by the fixed portions 5 (5A, 5B) in a displaceable state by the four beams 4 (4a, 4b, 4c, 4d). Also, the arrangement of the four beams 4a, 4b, 4c, 4d is the same as in the first embodiment, and the beams 4a and 4c are Z
Are arranged symmetrically via the Z axis on the same straight line passing through the axis,
The beams 4b and 4d are also symmetrically arranged on the same straight line passing through the Z-axis via the Z-axis, and the straight lines along the beams 4a and 4c and the straight lines along the beams 4b and 4d are formed. The angle formed is an angle other than 90 degrees. As a specific example, for example, a straight line along the beams 4a and 4c, a beam 4b and a beam 4d
The acute angle formed by the straight line along the line 4a is 27 degrees, and the obtuse angle formed by the straight line along the beams 4a and 4c and the straight line along the beams 4b and 4d is 153 degrees.

In the second embodiment, the weight 3 has a square frame shape, and the sides 3a and 3b of the square frame as the weight 3 are arranged along the X-axis direction. The sides 3b and 3d of the rectangular frame are arranged along the Y-axis direction. In such a weight portion 3, when a Coriolis force is generated due to rotation about the Y axis, the weight portion 3 is arranged such that the sides 3a and 3c alternately approach the base 2 with the X axis as a central axis. Rotate and vibrate. In the second embodiment, the width of each of the sides 3a and 3c of the weight 3 is wider than the width of each of the sides 3b and 3d.

In the second embodiment, as shown in FIG. 4, the wide side 3a of the weight 3 is provided on the surface of the base 2.
The electrodes 7 (7a, 7b) for detecting angular velocities around the Y-axis are respectively formed at portions opposed to 3c with an interval therebetween.

The connecting beam 10 and the internal weight 11 which are characteristic in the second embodiment are provided inside a square frame as the weight 3. That is, as shown in FIG. 4, the connecting beam 10 is arranged along the Y axis so as to span the sides 3a and 3c along the X axis direction of the square frame. The internal weights 11a and 11b are connected to the connecting beams 10 respectively.
Are supported by cantilever beams 12a and 12b.

On the surface of the base 2, the internal weight 11
Electrodes 6 (6a, 6b) for detecting the angular velocity around the X-axis are formed at portions opposed to a and 11b with an interval therebetween.

In the second embodiment, the weight 3
A driving electrode unit 13 (13a, 13b) is provided as a driving unit for causing the device to horizontally vibrate around the Z axis. FIG. 5 shows an enlarged view of a part of the driving electrode unit 13. As shown in FIG. 5, the driving electrode unit 13 includes a plurality of comb-shaped fixed electrodes 14 and a plurality of comb-shaped movable electrodes 15.

Each of the movable electrodes 15 is formed to extend outward from the wide side 3a, 3c of the weight 3 respectively. In addition, the fixing portion 16 (16a, 16b) is spaced apart from the wide side 3a of the weight portion 3 by an interval.
b, fixed portions 17 (17a, 17b) are fixedly arranged at intervals, and the fixed electrodes 14 extend from the fixed portions 16, 17 so as to mesh with the movable electrode 15 at intervals. Is formed.

In such a driving electrode portion 13, the fixed electrode 14 extending from the fixed portion 16a (17a) and the fixed electrode 14 extending from the fixed portion 16b (17b) are respectively provided. Voltages having phases different from each other by 180 degrees are applied. Thereby, the fixed electrode 14
An electrostatic force is generated between the movable electrode 15 and the movable electrode 15, and the electrostatic force changes according to the applied voltage. Therefore, the position of the movable electrode 15 with respect to the fixed electrode 14 fluctuates, and the weight 3 can be vibrated.

In the second embodiment, the fixed electrode 14 and the movable electrode 15 are used to cause the driving electrode portion 13 to horizontally vibrate the weight 3 around the Z axis.
Are formed in radial directions about the Z axis.

In the second embodiment, the weight 3
Monitoring means 20 (20a, 20a,
20b, 20c, and 20d) are provided. FIG. 6 schematically shows an example of the monitoring means. The monitor means 20 shown in FIG.
And a comb-shaped fixed electrode 22. The movable electrode 21 extends from the corner of the square frame of the weight 3 to Z
It is formed to extend in a radial direction about the axis. A fixed portion 23 is fixedly disposed on the base 2 in the vicinity of the movable electrode 21, and the fixed electrode 22 is fixed to the fixed portion 2.
3 is formed to extend so as to mesh with the movable electrode 21 with an interval.

In the monitor means 20, the capacitance between the movable electrode 21 and the fixed electrode 22 changes due to the driving vibration of the weight portion 3 as described above. 22 and the status of the drive vibration of the weight 3 can be monitored based on the detection signal. It should be noted that the weight 3
There are various configurations for monitoring the state of the drive vibration of this embodiment, and any of the configurations may be employed here, and the description thereof will be omitted.

The angular velocity detecting element 1 shown in the second embodiment is configured as described above. In the angular velocity detecting element 1 of the second embodiment, for example, when the driving electrode section 13 is driven, the weight section 3 is driven and vibrated together with the internal weight section 11. When rotated about the Y-axis in this driving vibration state, the weight 3 rotates together with the internal weight 11 in a rotational direction around the X-axis by the Coriolis force caused by the rotation.

The spacing between the sides 3a, 3b of the weight 3 and the electrodes 7 (7a, 7b) for detecting the angular velocity around the Y-axis fluctuates due to the rotational vibration of the weight 3 caused by the rotation about the Y-axis. The weight portion 3 and the electrode 7 for detecting the angular velocity around the Y-axis.
The capacitance between (7a, 7b) changes. This change in the capacitance is detected by the Y-axis angular velocity detecting electrodes 7 (7a, 7a).
b), and the angular velocity of rotation about the Y axis can be detected based on this detection signal.

As described above, when the weight portion 3 is rotated about the X axis while being driven and vibrated together with the internal weight portion 11, the internal weight is caused by the Coriolis force around the Y axis caused by this rotation. The portion 11 (11a, 11b) vibrates, and the interval between the internal weight 11 and the electrode 6 for detecting the angular velocity around the X-axis changes. Thus, the capacitance between the internal weight 11 and the electrode 6 for detecting the angular velocity around the X-axis changes.
This change is detected from the electrode 6 for detecting the angular velocity around the X axis, and the angular velocity of rotation around the X axis can be detected based on the detection signal.

As described above, the angular velocity detecting element 1 of the second embodiment is of a two-axis detection type capable of detecting the angular velocity of rotation about the X axis and the angular velocity of rotation about the Y axis. are doing.

According to the second embodiment, the arrangement of the four beams similar to that of the first embodiment is provided, so that the resonance frequency of the driving vibration of the weight 3 and the resonance frequency of the detected vibration are provided. Can easily be made lower than the resonance frequency of the unnecessary vibration. Accordingly, it is possible to prevent the accuracy of the angular velocity detection from being deteriorated due to the unnecessary vibration, and to improve the reliability of the angular velocity detection.

Further, the weight portion 3 is hardly displaced by the Coriolis force caused by the rotation about the X axis by the four arrangements as described above. However, in the second embodiment, Since the internal weight 11 that vibrates due to the Coriolis force caused by the rotation about the X-axis and the electrode 6 for detecting the angular velocity around the X-axis that detects the vibration of the internal weight 11 are provided, The angular velocity of rotation can also be detected.

Further, in the configuration of the second embodiment,
The weight portion 3 is formed in a frame shape, and the connecting beam 10 along the Y axis and the internal weight portion 11 supported by the connecting beam 10 are provided inside the frame as the weight portion 3. The resonance frequency of the vibration caused by the rotation of the internal weight 11 about the X axis, the resonance frequency of the detected vibration caused by the rotation of the weight 3 around the Y axis, and the driving of the weight 3 about the Z axis It becomes easy to design the angular velocity detecting element 1 so that the resonance frequency of the vibration becomes the required frequency.

That is, since the resonance frequency of the driving vibration and the detection vibration of the weight 3 is greatly affected by the four beams 4, the width, length, thickness, and the like of the four beams 4 are appropriately adjusted. By setting, the frequency can be set.

The resonance frequency of the vibration detected by the internal weight 11 can be changed by changing the beam width of the connecting beam 10.
The variable control can be performed without substantially affecting the driving vibration of the weight portion 3 and the detection vibration caused by the rotation about the Y axis.
In other words, the resonance frequency of the detected vibration caused by the rotation of the internal weight 11 about the X axis is the resonance frequency of the drive vibration of the weight 3 and the resonance of the detected vibration caused by the rotation of the weight 3 about the Y axis. Variable control can be performed in a state almost independent of the frequency. For this reason, as described above, it becomes easy to design the angular velocity detecting element 1 so that the resonance frequencies become the set frequencies, and the time required for the design can be reduced.

It should be noted that the present invention is not limited to the above embodiments, but can take various embodiments. For example, in each of the above embodiments, each beam 4 has a linear shape, but the shape of the beam 4 is not limited, and can take various forms. For example, in order to provide more elasticity, each beam 4 may be formed in a curved shape, or may be a beam 4 having a bent portion. However, the beam 4 is provided so as to extend in a direction away from the weight portion 3.

In the first embodiment, the weight 3
Is circular, and in the second embodiment, the shape of the frame that is the weight 3 is square, but the shape of the weight 3 is limited to the shape shown in each of the above embodiments. is not. The four beams 4 are not limited to the shape of the weight 3
Are arranged in a specific manner as shown in each of the above embodiments, so that the weight 3
Both the resonance frequency of the drive vibration and the resonance frequency of the detection vibration can be made lower than the resonance frequency of the unnecessary vibration of the weight portion 3, and the accuracy of the angular velocity detection can be improved.

Further, in the second embodiment, the shape of the internal weight 11 (11a, 11b) is square, but the shape of the internal weight 11 (11a, 11b) is limited to a square. Instead, it can take various shapes. The connecting beam 10 is connected to the side 3 a of the weight 3.
And the side 3c.
It is sufficient that 0 has a configuration extending along the Y axis. For example, depending on the shape of the internal weight 11, it may not be spanned between the sides 3 a and 3 c of the weight 3.

Further, in the second embodiment, the monitoring means 20 is formed, but this monitoring means 20 is provided as necessary and may be omitted.

[0069]

According to the present invention, each of the four beams is closer to the other side than the angle between one of the two adjacent beams adjacent to each other in the direction of orbiting the weight. Since the angle formed is set to be large, the resonance frequency of the driving vibration of the weight and the resonance frequency of the detection vibration are both set to the resonance of the unnecessary vibration (in other words, the vibration mode other than the driving vibration and the detection vibration). It becomes easier to make the frequency lower than the frequency so as to be hardly affected by the unnecessary vibration.

As a result, it is possible to prevent the accuracy of the angular velocity detection from deteriorating due to the unnecessary vibration, to improve the accuracy of the angular velocity detection, and to enhance the reliability of the angular velocity detection of the angular velocity detecting element. .

The weight portion is configured to rotate and vibrate around the X axis by Coriolis force caused by rotation around the Y axis.
In the case where the Y-axis rotation angular velocity detecting unit for detecting the rotational vibration caused by the rotation of the weight part around the Y-axis is provided, depending on the arrangement position of the four unique beams as described above, It is possible to prevent the accuracy of detection of the angular velocity of rotation around the Y axis from deteriorating due to unnecessary vibration, and to accurately detect the angular velocity around the Y axis.

The weight section is provided with an X-axis detection vibration section and an X-axis angular velocity detection section for detecting vibration caused by rotation of the X-axis detection vibration section about the X-axis. In the above, the weight portion is hardly oscillated by the Coriolis force caused by the rotation around the X-axis due to the unique four beam arrangement as described above. The X-axis detection vibrating section vibrates by the Coriolis force caused by the rotation about the X-axis. Therefore, when the X-axis rotation is performed, the X-axis detection vibration section is rotated by the Coriolis force caused by the rotation about the X-axis. The axis detection vibration unit vibrates, and this vibration is detected by the X-axis angular velocity detection unit. With such a configuration, the angular velocity detecting element may be a two-axis detection type angular velocity detecting element capable of detecting the angular velocity of rotation around the X axis and the angular velocity of rotation around the Y axis. it can.

The weight portion has a frame shape, and a connecting beam and an internal weight portion functioning as an X-axis detection vibration portion are provided inside the frame as the weight portion. In the case where the X-axis angular velocity detecting electrode, which is an X-axis angular velocity detecting unit for detecting vibration caused by rotation about the X-axis, is provided, the beam width of the connecting beam is varied. The resonance frequency of the vibration caused by the rotation of the internal weight around the X axis can be varied. The variable control of the resonance frequency can be performed by changing the resonance frequency of the horizontal rotation vibration about the Z axis of the weight. The resonance frequency of the rotational vibration caused by the rotation of the weight portion about the Y axis can be substantially changed.

That is, the variable control of the resonance frequency of the vibration caused by the rotation of the internal weight around the X axis is performed by controlling the resonance frequency of the horizontal vibration of the weight and the rotation vibration caused by the rotation of the weight around the Y axis. And the resonance frequency of the vibration caused by the rotation of the internal weight around the X axis, the resonance frequency of the horizontal rotation vibration of the weight, and the Y of the weight as described above. It becomes easy to design the angular velocity detecting element so that the resonance frequency of the rotational vibration caused by the rotation around the axis becomes the required frequency.

Each of the beams is formed so as to extend from the surface of the base and to extend in parallel with the surface of the base.
The two beams are formed in pairs, and the two beams in the same group are arranged at positions symmetrical with respect to the center axis of the horizontal rotation of the weight. With a simple configuration, the weight can be stably vibrated as described above, and the accuracy of angular velocity detection can be improved.

[Brief description of the drawings]

FIG. 1 is a perspective view schematically showing main components of an angular velocity detecting element according to a first embodiment.

FIG. 2 is an explanatory diagram schematically showing specific components of the angular velocity detecting element according to the first embodiment;

FIG. 3 is a graph showing an example of a relationship between angles formed by four beams and resonance frequencies of various vibrations of a weight portion, obtained from an experiment performed by the present inventors.

FIG. 4 is a plan view schematically showing an angular velocity detecting element according to a second embodiment.

FIG. 5 is a diagram for explaining an example of a driving unit shown in the second embodiment.

FIG. 6 is a diagram for explaining an example of a monitor shown in the second embodiment.

FIG. 7 is a model diagram showing a conventional example of an angular velocity detecting element.

8 is a model diagram schematically showing a weight portion and a beam of the angular velocity detecting element of FIG. 7 extracted.

FIG. 9 is an explanatory diagram schematically showing an example of various vibration states of the weight shown in FIG. 7;

FIG. 10 shows a case where four beams are arranged in a conventional arrangement, and when any one of the thickness, width and length of the beam is varied as a parameter, the resonance frequency of various vibrations of the weight portion is changed. It is a graph which shows the experimental result which investigated how it changes.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Angular velocity detection element 2 Base 3 Weight part 4 Beam 6 Electrode for X-axis angular velocity detection 7 Electrode for Y-axis angular velocity detection 10 Connecting beam 11 Internal weight part 13 Drive electrode part

 ────────────────────────────────────────────────── ─── Continued on the front page (72) Inventor Shinji Kobayashi 2-26-10 Tenjin, Nagaokakyo-shi, Kyoto Murata Manufacturing Co., Ltd. F-term (reference) 2F105 BB01 CC04 CD03 CD05

Claims (6)

[Claims] 1. A base, a weight portion opposed to a surface of the base with an interval, four beams for supporting the weight portion in a displaceable manner, a surface of the base and a weight Driving means for horizontally rotating and vibrating the weight portion along the surface of the base with the Z axis perpendicular to the central axis as the central axis, wherein the four beams are respectively
Each of these beams is formed to extend in a direction away from the weight portion, and each of these beams is larger than an angle formed with one side of both adjacent beams adjacent to each other in a direction around the weight portion. An angle formed with the other side is increased, and both the resonance frequency of the driving vibration of the weight portion by the driving means and the resonance frequency of the detection vibration of the weight portion caused by the Coriolis force are equal to the driving vibration. An angular velocity detecting element, wherein the angular velocity detecting element is configured to be lower than a resonance frequency of a vibration mode other than the detected vibration. 2. A weight portion, when a Coriolis force is generated due to rotation about a Y-axis parallel to a surface of a base due to an arrangement of four beams, the Y-axis and the Z-axis. 2
Angular velocity detection around the Y-axis that uses a capacitance to detect the rotational vibration caused by the rotation of the weight around the Y-axis by using the capacitance as the center axis about the X-axis orthogonal to the axis. The angular velocity detecting element according to claim 1, wherein a portion is provided. 3. The weight portion is provided with an X-axis detection vibration portion that vibrates due to a Coriolis force caused by rotation about the X-axis as a center axis. 3. The angular velocity detecting element according to claim 2, further comprising: an X-axis angular velocity detecting unit for detecting the vibration caused by using the capacitance. 4. The weight portion has a frame shape, and a connecting beam extending in the Y-axis direction from the frame and a X-axis supported by the connecting beam are provided inside the frame serving as the weight portion. An X-axis detection vibration part vibrating due to the Coriolis force caused by the rotation about the center axis and an internal weight part are formed. An electrode for detecting the angular velocity around the Y axis, which is a portion, is formed.
The angular velocity detecting element according to claim 3, wherein an electrode for detecting an angular velocity around the X-axis, which is an angular velocity detecting section around the X-axis, is formed at a portion facing the internal weight portion. 5. The apparatus according to claim 1, wherein each of the beams is formed so as to extend at a distance from the surface of the base and parallel to the surface of the base. The angular velocity detecting element as described in the above. 6. The four beams form a set of two beams, and the two beams of the same set are respectively disposed at positions symmetrical with respect to the center axis of horizontal rotation of the weight. The angular velocity detecting element according to any one of claims 1 to 5, wherein: