JP2000028365A - Angular velocity sensor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve detection sensitivity of angular velocity by detecting angular velocity without being affected by acceleration even when acceleration is added. SOLUTION: In an angular velocity sensor 1, a substrate 2 is provided with an angular velocity detecting element 3 to detect angular velocity Ω about the z-axis and with an acceleration detecting element 19 to detect acceleration added along the y-axis at a location different from the angular velocity detecting element 3. The angular velocity detecting element 3 is constituted of the first and second supporting beams 5 and 7, the first and second oscillators 6 and 8, etc. The acceleration detecting element 19 is constituted of the third supporting bean 21, the third oscillator 22, etc. The first displacement detecting parts 18L and 18R detect the displacement of the second oscillator 8 along the y-axis to detect the angular velocity Ω. The second displacement detecting parts 27L and 27R detect the displacement of the third oscillator 22 along the y-axis to detect the displacement of the second oscillator 8 due to acceleration.

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 suitable for detecting an angular velocity acting on, for example, a moving object or a rotating body.

[0002]

2. Description of the Related Art In general, as an angular velocity sensor according to the prior art, there is known an angular velocity sensor described in, for example, Japanese Patent Application Laid-Open No. 5-31576.

Here, the angular velocity sensor described in Japanese Patent Application Laid-Open No. Hei 5-321576 is provided on a substrate, and is provided on the substrate and is perpendicular to first and second axes which are orthogonal to the substrate in the horizontal direction. An angular velocity detecting element for detecting an angular velocity applied around a third axis orthogonal to.

The angular velocity detecting element is supported on a substrate by a first support beam, and is provided with a first vibrator provided to be vibrable in a direction of a first axis. 2
A second vibrating body supported by the supporting beam and vibrating in the directions of the first and second axes, and vibration generating means for vibrating the first vibrating body in the direction of the first axis A second vibration generated in the second vibrating body when an angular velocity is applied around a third axis in a state in which the first vibration body is vibrating in the direction of the first axis by the vibration generating means. And an angular velocity detecting means for detecting the displacement of the shaft in the axial direction.

In this angular velocity sensor, when the first vibrating body is vibrated in a direction of a first axis parallel to the substrate by the vibration generating means, the first vibrating body is moved to the second supporting beam. The second vibrator supported by vibrates also in the direction of the first axis, which is the same axis. When the entire sensor rotates around a rotation axis (third axis) perpendicular to the substrate while the second vibrating body is vibrating, the second vibration is generated by the Coriolis force corresponding to the rotational force. The body vibrates in a direction orthogonal to the vibration direction of the first vibrating body (the direction of the second axis).
Then, the angular velocity detecting means can detect the angular velocity applied to the entire sensor by detecting the displacement amount of the second vibrating body during vibration.

[0006]

In the angular velocity sensor according to the prior art described above, when acceleration is applied in the direction of the second axis, the acceleration causes the second vibrating body to be displaced in the direction of the second axis. I do. At this time, the angular velocity detecting means also detects the amount of displacement of the second vibrating body due to the acceleration as being based on the angular velocity. That is, even when the entire sensor does not rotate around the third axis perpendicular to the substrate, when the acceleration is applied in the direction of the second axis, the angular velocity detecting means determines the amount of displacement of the second vibrator. Will be detected.

As described above, when the acceleration is applied in the direction of the second axis, the displacement of the second vibrating body due to the acceleration is added as noise, so that there is a problem that the accuracy of detecting the angular velocity is reduced. .

The present invention has been made in view of the above-mentioned problems of the prior art, and the present invention provides an angular velocity capable of detecting an angular velocity applied around the third axis even when acceleration is applied in the direction of the second axis. It is intended to provide a sensor.

[0009]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention is directed to a substrate and a device which is provided on the substrate and which is perpendicular to first and second axes which are perpendicular to the substrate in a horizontal direction. An angular velocity detecting element for detecting an angular velocity applied around a third axis orthogonal to the first axis.
A first vibrating member supported by the supporting beam of the first vibrating member and capable of vibrating in the direction of the first axis; and a first vibrating member supported by the second vibrating member on the first vibrating member. A second vibrator provided so as to be capable of vibrating in the direction of the axis, vibration generating means for vibrating the first vibrator in the direction of the first axis; An angular velocity detecting means configured to detect a displacement in the second axial direction generated in the second vibrating body when an angular velocity is applied around the third axis in a state where vibration is applied in the direction of the first axis. Applied to the specified angular velocity sensor.

A feature of the structure adopted by the invention of claim 1 is that the substrate is provided with an acceleration detecting element for detecting an acceleration applied in the direction of the second axis at a position different from the angular velocity detecting element. A third vibrator supported by the third support beam and capable of vibrating in the direction of the second axis; and a second vibrator generated in the third vibrator when acceleration is applied in the direction of the second axis. , Which is constituted by acceleration detecting means for detecting displacement in the axial direction.

With this configuration, the angular velocity detecting element provided on the substrate detects the angular velocity applied around the third axis. That is, the vibration generating means causes the first and second vibrators to vibrate in the first axial direction. Then, in a state where the second vibrating body is vibrating in the direction of the first axis, a third
When the angular velocity around the axis is applied, the second vibrating body vibrates in the direction of the second axis by Coriolis force corresponding to the angular velocity. For this reason, the angular velocity detecting means detects the amount of displacement of the second vibrating body during vibration, and detects the angular velocity applied to the entire sensor.

An acceleration detecting element provided on the substrate at a position different from the angular velocity detecting element detects a second axial acceleration applied to the entire sensor including the angular velocity detecting element. That is, when acceleration in the second axial direction is applied to the entire sensor, the third vibrator is displaced in the direction of the second axis. At this time, since the acceleration detecting means detects the displacement amount of the third vibrating body, it detects only the angular velocity applied to the entire sensor.

On the other hand, when the acceleration in the second axial direction is applied to the entire sensor, the second vibrating body is also displaced in the direction of the second axis. Therefore, the angular velocity detecting means adds the angular velocity applied to the entire sensor. To detect acceleration. At this time, by canceling the detection signal of the acceleration detecting means from the detection signal of the angular velocity detecting means, only the angular velocity applied to the entire sensor can be detected.

According to a second aspect of the present invention, the third supporting beam has a spring constant substantially equal to the spring constant of the second supporting beam, and the third vibrating member is provided with the second vibrating member. That is, it has a configuration having a mass substantially equal to the body.

Thus, when acceleration in the second axial direction is applied to the entire sensor, the amount of displacement of the third vibrating body in the direction of the second axis due to this acceleration and the second vibrating body become the second vibrating body. And the displacement amount displaced in the direction of the axis can be made substantially equal. Therefore, by detecting the displacement of the third vibrating body by the angular velocity detecting means, it is possible to detect the displacement of the second vibrating body due to acceleration.

[0016]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of an angular velocity sensor according to the present invention will be described below in detail with reference to FIGS.

1 is an angular velocity sensor, 2 is the angular velocity sensor 1
The substrate 2 is formed of, for example, a glass material. Also, the substrate 2
Is provided with an angular velocity detecting element 3 and an acceleration detecting element 19 described later. Then, the angular velocity detecting element 3 detects the angular velocity applied to the angular velocity sensor 1, and the acceleration detecting element 19 detects the acceleration applied to the angular velocity sensor 1.

Reference numeral 3 denotes an angular velocity detecting element formed of low resistance polysilicon or single crystal silicon doped with P, Sb, etc. on the substrate 2, and the angular velocity detecting element 3 is disposed on the left side of the substrate 2. , A support portion 4, a first support beam 5, a first vibrator 6, a second support beam 7, and a second vibrator 8, which will be described later.
And so on.

Reference numerals 4, 4,... Denote four support portions provided on the substrate 2, and the support portions 4 are arranged at four corners of the angular velocity detecting element 3 having a substantially square shape. Then, the base end side of the first support beam 5 is attached to each support portion 4, and these four support beams 5 are moved toward the center of the angular velocity detecting element 3 in a Y direction.
It extends in the axis (second axis) direction. Further, a first vibrating body 6 is attached to a tip end of the first support beam 5.
For this reason, the first vibrating body 6 is supported by these four support beams 5 so as to be able to vibrate in the X-axis (first axis) direction.

Reference numeral 6 denotes a first vibrator supported by the first support beam 5 so as to be displaceable in the direction of the X axis while being separated from the surface of the substrate 2. The first vibrator 6 has a rectangular shape. It is formed in a frame shape, and a second support beam 7, a second vibrating body 8, and the like are disposed in a frame of the first vibrating body 6. Further, on the long sides before and after the first vibrating body 6, movable side vibrating electrodes 13, 13 to be described later are formed to protrude outside the frame.

Are four second support beams, each of the support beams 7 having its base end side attached to the center of the short side of the first vibrator 6, Extend in the X-axis direction within the frame. The distal end of each support beam 7 is connected to a second vibrating body 8.
Mounted on

Reference numeral 8 denotes a second vibrating member disposed in the frame of the first vibrating member 6. The second vibrating member 8 includes two arm portions 8A extending in the Y-axis direction, Connecting portion 8B for connecting arm portion 8A
Thus, both ends of each arm 8A are attached to the tip end of each support beam 7. For this reason, the second vibrating body 8 is attached to the first vibrating body 6 via the four support beams 7, and is capable of vibrating in the Y-axis direction.
Further, at the center of the connecting portion 8B of the second vibrating body 8, movable side detection electrodes 16, 16 to be described later are formed toward left and right.

Here, the first supporting beam 5, the first vibrating body 6, and the second vibrating body 8 constitute a vibrating system 9 that vibrates in the X-axis direction which is the first axial direction. Support beam 7,
The detection system 10 vibrates in the Y-axis direction, which is the second axial direction, by the second vibrator 8. And the vibration system 9
Has a vibration side resonance frequency f1 set by the mass of the first vibrating body 6 and the second vibrating body 8 and the spring constant of the first support beam 5, and the detection system 10 It has a detection-side resonance frequency f2 set by the mass of the body 8 and the spring constant of the second support beam 7.

Further, the vibration side resonance frequency f1 of the vibration system 9 and the detection side resonance frequency f2 of the detection system 10 are set to substantially equal values. Thereby, the Coriolis force F acting on the second vibrating body 8 is increased, and when the angular velocity Ω is applied around the Z axis (third axis), the second vibrating body 8 is further increased in the Y-axis direction. Can be displaced.

Numerals 11 and 11 denote vibration fixing portions provided on the substrate 2 so as to be separated from each other in the front and rear directions.
Is fixedly provided on the substrate 2 with the first vibrator 6 sandwiched between the front and rear.

Reference numerals 12 and 12 denote fixed-side vibrating electrodes formed so as to protrude from the vibration fixing portion 11 toward the first vibrating body 6. Each of the fixed-side vibrating electrodes 12 faces the vibration fixing portion 11. It is composed of six protruding electrode plates 12A. Each of the electrode plates 12A alternately faces each of the electrode plates 13A, which will be described later, formed integrally with the first vibrator 6 with a gap.

Reference numerals 13, 13 denote movable-side vibrating electrodes formed on the first vibrating body 6, and each movable-side vibrating electrode 13 is disposed on a long side before and after the vibrating body 6. The movable-side vibrating electrode 13 is constituted by seven electrode plates 13A protruding forward and backward toward the vibration fixing portion 11, and these electrode plates 13A are arranged in a comb shape. And
The movable-side vibrating electrode 13 constitutes a vibration generator 17 together with the fixed-side vibrating electrode 12.

The substrates 14 are separated from each other in the left and right directions.
The fixing portions for detection 14 are arranged in a space surrounded by the second support beam 7 and the second vibrating body 8.

Reference numerals 15 and 15 denote fixed-side detection electrodes provided on the fixed portion 14 for detection. Each fixed-side detection electrode 15 is an arm extending left and right from both the front and rear sides of the fixed portion 14 for detection. 15A and each electrode plate 16 of the movable-side detection electrode 16 described later.
B so that the arms 15A face each other alternately with a gap.
And six electrode plates 15B protruding inward from.

Reference numerals 16 and 16 denote connecting portions 8B of the second vibrating body 8.
The movable-side detection electrodes 16 are formed so as to project leftward and rightward from the center of the arm. Each of the movable-side detection electrodes 16 includes an arm 16A extending in the Y-axis direction along the axis OO, and the arm 16A. And six electrode plates 16B extending at equal intervals in the front and rear directions (X-axis direction) to form an antenna.
The movable-side detection electrode 16 and the fixed-side detection electrode 15 constitute first displacement detection units 18L and 18R.

In the angular velocity detecting element 3, only the support portions 4 are fixed to the substrate 2, and the first support beam 5, the first vibrator 6, the second support beam 7, and the second vibrator 8 are Four points are supported at a predetermined distance from the substrate 2. Also,
Since each first support beam 5 extends in the Y-axis direction, it is bent in the X-axis direction, thereby displacing the first vibrating body 6 in the X-axis direction. Since the second vibrating body 8 is extended in the axial direction and flexed in the Y-axis direction,
Can be displaced in the direction of the Y axis.

Numerals 17 and 17 denote vibration generators provided apart from each other in the front and rear directions. Each of the vibration generators 17 is composed of the fixed vibration electrode 12 and the movable vibration electrode 13 and Equal gaps are formed between the respective electrode plates 12A of the electrode 12 and the respective electrode plates 13A of the movable vibration electrode 13.

Here, when a driving signal such as a pulse wave or a sine wave having a frequency f0 having an opposite phase is applied between the fixed-side vibrating electrode 12 and the movable-side vibrating electrode 13, the front and rear electrode plates 12A, Electrostatic attraction is generated alternately between 13A, and each vibration generating unit 17 repeats approaching and separating. Thus, each vibration generating unit 17 vibrates the first vibrating body 6, the second vibrating body 8, and the like in the X-axis direction.

Reference numerals 18L and 18R denote first and left displacement detecting sections as angular velocity detecting means. Each of the displacement detecting sections 18L and 18R comprises a fixed side detecting electrode 15 and a movable side detecting electrode 16. ing.

Each of the displacement detectors 18L and 18R is initially in the state shown in FIG. 3, and includes an electrode plate 15B of the fixed-side detection electrode 15 and an electrode plate 16B of the movable-side detection electrode 16.
B, when facing each other alternately, the left displacement detector 18L
Of the adjacent electrode plates 15B and 16B are in a state in which the distance d0 with a narrow gap and the distance d0 'with a wide gap are alternately positioned.

On the other hand, the right displacement detecting section 18R is configured similarly to the left displacement detecting section 18L,
The spacing between B and 16B is such that the spacing d0 with a narrow gap and the spacing d0 'with a wide gap are alternately positioned. Then, the electrode plate 15B of the left displacement detecting unit 18L,
16B and the right side displacement detector 18
The distances d0 and d0 'between the R electrode plates 15B and 16B are line-symmetrical on both the left and right sides of the connecting portion 8B.

For this reason, at the initial stage, the capacitance C0 of the parallel plate capacitor due to the small clearance d0 is set.
Similarly, at the initial stage, the relationship between the capacitance C0 'of the parallel plate capacitor due to the large gap d0' is as follows.
It becomes like following Formula 1.

[0038]

## EQU1 ## C0 ≫C0 '

For this reason, at the initial stage when the angular velocity detecting element 3 is not operated, only the side of the gap d0 with a narrow gap is configured as a parallel plate capacitor. As a result, when the angular velocity .OMEGA. Acts on the angular velocity detecting sensor 1, each of the displacement detecting sections 18L and 18R detects a change in a small separation dimension d0 between the electrode plates 15B and 16B as a change in capacitance. It is.

Reference numeral 19 denotes an acceleration detecting element formed on the substrate 2 by polysilicon, single crystal silicon, or the like, similarly to the angular velocity detecting element 3. The acceleration detecting element 19 is different from the angular velocity detecting element 3 in FIG. As shown in FIG. 2, it is disposed on the right side of the substrate 2 and includes a support portion 20, a third support beam 21, a third vibrating body 22, and the like, which will be described later.

Reference numerals 20 and 20 denote two support portions provided on the substrate 2, and each of the support portions 20 is disposed on both left and right ends of the acceleration detecting element 19 having a substantially square shape. Each of the support portions 20 is attached to the third support beam 21 two by two, and extends in the X-axis direction. Further, the distal end side of each support beam 21 is attached to the third vibrating body 22. Since the length of the third support beam 21 extending in a long shape is substantially equal to the length of the second support beam 7, the spring constant thereof is also substantially equal to that of the second support beam 7. Value.

Reference numeral 22 denotes a third vibrator, and the third vibrator 2
2 is substantially H by two arms 22A and a connecting portion 22B connecting the arms 22A in substantially the same manner as the second vibrating body 8.
Each of the arms 22A has a support beam 21
It is mounted on the tip side. For this reason, the third vibrating body 22 is attached to the supporting portion 20 via the four supporting beams 21 and is capable of vibrating in the Y-axis (second axis) direction.
Also, at the center of the connecting portion 22B of the third vibrating body 22,
Movable detection electrodes 26, 26, which will be described later, are formed toward the left and right. The mass of the third vibrating body 22 is set to a value substantially equal to the mass of the second vibrating body 8.

Here, the third supporting beam 21 and the third vibrating body 22 constitute a detection system 23 that vibrates in the direction of the Y axis which is the second axial direction. The detection system 23 has a detection-side resonance frequency f3 set by the mass of the third vibrating body 22 and the spring constant of the third support beam 21. Since the mass of the third vibrating body 22 is substantially equal to that of the second vibrating body 8 and the spring constant of the third supporting beam 21 is substantially equal to the spring constant of the second supporting beam 7, the detection system 23 is the detection-side resonance frequency f3 of the detection system 10.
It is set to a value approximately equal to 2.

Reference numerals 24, 24 denote left and right sides of the substrate 2
The detection fixing portions 24 are provided in a space surrounded by the third support beam 21 and the third vibrating body 22.

Reference numerals 25, 25 denote fixed-side detection electrodes provided on the fixed portion for detection 24. Each fixed-side detected electrode 25 is an arm extending left and right from both the front and rear sides of the fixed portion for detection 24. 25A and each electrode plate 26 of a movable-side detection electrode 26 described later.
B so that the arms 25A face each other alternately with a gap.
Electrode plates 25 formed to protrude inward from
B.

Reference numerals 26, 26 designate connecting portions 2 of the third vibrating body 22
The movable detection electrodes 26 are formed substantially in the same manner as the movable detection electrodes 16 of the second vibrating body 8, with the movable detection electrodes 26 formed to the left and right from the center of 2B. An arm 26A extending in the Y-axis direction along O and six electrode plates 26B extending frontward and rearward (X-axis direction) at equal intervals on the arm 26A are formed in an antenna shape. . The movable detection electrode 26 is fixed to the fixed detection electrode 2.
5 together with the second displacement detector 27L, 27R.

The acceleration detecting element 19 is connected to each support 2.
Only 0 is fixed to the substrate 2, and the third support beam 21 and the third vibrating body 22 are supported at two points at a predetermined distance from the substrate 2. In addition, since each third support beam 21 extends in the X-axis direction, the third vibrating body 22 can be displaced in the Y-axis direction by bending in the Y-axis direction.

Reference numerals 27L and 27R denote left and right second displacement detectors serving as acceleration detectors. Each of the displacement detectors 27L and 27R includes a fixed-side detection electrode 25 and a movable-side detection electrode 26. Have been.

As shown in FIG. 3, each of the displacement detectors 27L, 27R is provided with a displacement detector 18L,
It is configured almost similarly to 18R. That is, at the initial stage, when the electrode plates 25B of the fixed-side detection electrodes 25 and the electrode plates 26B of the movable-side detection electrodes 26 alternately face each other, the distance between the adjacent electrode plates 25B and 26B of the left displacement detection unit 27L. Is in a state in which the spacing d0 with a narrow gap and the spacing d0 'with a wide gap are alternately positioned.

On the other hand, the distance between the adjacent electrode plates 25B and 26B of the right displacement detector 27R is such that the distance d0 with a narrow gap and the distance d0 'with a wide gap are alternately positioned. Then, the electrode plate 2 of the left displacement detection unit 27L
5B and 26B, and the separation dimensions d0 and d0 of the electrode plates 25B and 26B of the right displacement detector 27R.
′ Has a line-symmetrical relationship on both the left and right sides of the connecting portion 22B.

Therefore, each of the displacement detectors 27L, 27R
In the same manner as the first displacement detecting units 18L and 18R, only the separation dimension d0 with a narrow gap is configured as a parallel plate capacitor, and the capacitance C1 on the separation dimension d0 is determined by the first displacement detecting units 18L and 18R. Is set to a value that is substantially equal to the capacitance C0. As a result, the acceleration G
Is applied, the displacement detection units 27L and 27R detect a change in the separation dimension d0 in which the gap between the electrode plates 25B and 26B is small as a change in capacitance.

The angular velocity sensor 1 according to the present embodiment is configured as described above. Next, a basic detection operation when an angular velocity Ω is applied around the Z axis will be described with reference to FIG.

First, with respect to the angular velocity detecting element 3, when a driving signal having an opposite phase is applied to the vibration generators 17 located on the left and right sides, the electrostatic attraction is applied between the electrode plates 12A and 13A. 17, the first vibrating body 6 and the second vibrating body 8 generate vibrations in the X-axis direction. In this case, the first support beams 5 only bend in the X-axis direction and the second support beams 7 do not bend in the X-axis direction.
Also vibrates only in the X-axis direction.

In this state, when an angular velocity Ω is applied around the Z axis (third axis), the following equation (2) is obtained in the Y axis (second axis) direction.
A Coriolis force F (inertial force) shown in FIG.

[0055]

F = 2 mΩv m: mass of the second vibrating body 8 Ω: angular velocity v: velocity of the second vibrating body 8 in the X-axis direction

The Coriolis force F causes the second
Vibrator 8 vibrates in the direction of the Y axis, and the second vibrator 8
In the first displacement detection units 18L and 18R, the vibration displacement of
The angular velocity Ω around the Z-axis can be detected by detecting the change in capacitance between the fixed-side detection electrode 15 and the movable-side detection electrode 16.

In particular, the respective electrode plates 15B and 16B of the first displacement detecting portions 18L and 18R are line-symmetrically spaced apart from each other on the left and right sides of the connecting portion 8B by the spacing dimensions d0 and d0 '. It is arranged in. For this reason, as shown in FIG. 4, when the second vibrating body 8 is displaced to the left, the displacement detection unit 18L on the left side of the connecting portion 8B causes the electrode plates 15B, 1
The separation dimension d0 between 6B becomes smaller by the displacement dimension (-Δdc0). At this time, the left displacement detector 18L outputs a displacement signal of the displacement capacitance (+ ΔCc0).

Here, the displacement dimension (-Δdc0) means that the second vibrating body 8 is displaced by the Coriolis force F and the electrode plate 15
It shows the change in the separation dimension when the separation dimension between B and 16B is reduced with respect to the initial separation dimension d0. Further, the displacement capacity (+ ΔCc0) means the electrode plates 15B, 16B
The distance between the electrode plates 15B and 16B is reduced by the displacement dimension (-Δdc0), and the capacitance between the electrode plates 15B and 16B is reduced to the initial capacitance C0.
2 shows a change in the capacitance when the capacitance increases.

On the other hand, the displacement detector 18 on the right side of the connecting portion 8B
At R, the separation dimension d0 between the electrode plates 15B and 16B increases by the displacement dimension (+ Δdc0). At this time, the displacement detector 18R on the right side outputs a displacement signal of the displacement capacity (−ΔCc0). That is, when the second vibrating body 8 is displaced to the left, the displacement dimensions and displacement capacities of the left and right displacement detectors 18L and 18R are as shown in Table 1 below.

Here, the displacement dimension (+ Δdc0) means that the second vibrating body 8 is displaced by the Coriolis force F and the electrode plate 15
It shows a change in the separation dimension when the separation dimension between B and 16B is increased with respect to the initial separation dimension d0. Further, the displacement capacity (−ΔCc0) refers to the electrode plates 15B, 16B
The distance between them increases by the displacement size (+ Δdc0), and the capacitance between the electrode plates 15B and 16B becomes the initial capacitance C0.
2 shows a change in the capacitance when the capacitance decreases.

[0061]

[Table 1]

Then, by subtracting the displacement signal from the right displacement detector 18R from the displacement signal from the left displacement detector 18L as shown in the following equation (3), (2 × ΔCc0)
Can be detected. Thereby, the detection accuracy of the angular velocity Ω can be improved.

[0063]

(2 × ΔCc0) = + ΔCc0 − (− ΔCc0)

On the other hand, since the Coriolis force F does not act on the acceleration detecting element 19, the third vibrating body 22 does not displace even when an angular velocity Ω around the Z axis is applied. For this reason, in the second displacement detection units 27L and 27R,
The capacitance C1 between the fixed side detection electrode 25 and the movable side detection electrode 26 does not change, and the second displacement detection units 27L and 27R
Does not output a displacement signal.

Although the case where the second vibrating body 8 is displaced to the left by the Coriolis force F of the angular velocity Ω has been described, even when the second vibrating body 8 is displaced to the right by the Coriolis force F, Approximately the same displacement signal can be detected except that the sign of the displacement capacitance changes. That is, the left displacement detector 18L outputs a displacement signal of the displacement capacitance (−ΔCc0), and the right displacement detector 18R outputs the displacement capacitance (+
ΔCc0) is output. Therefore, by subtracting the two displacement signals as in Equation 3, ｛2 × (−
ΔCc0)｝ displacement signal can be detected.

Next, while adding the angular velocity Ω around the Z axis,
The detection operation when the acceleration G is applied in the axial direction will be described with reference to FIGS.

First, with respect to the angular velocity detecting element 3, drive signals having opposite phases are applied to the vibration generators 17 located on the left and right, and the first vibrator 6 and the second vibrator 8 are moved in the X-axis direction. Vibrate. In this state, when an angular velocity Ω is applied around the Z axis, the second vibrating body 8 vibrates in the Y axis direction due to the Coriolis force F.

When an acceleration G, for example, to the right, acts on the entire angular velocity sensor 1 along the Y-axis direction,
The second vibrating body 8 is displaced in the direction of the Y axis toward the left side opposite to the acceleration G. Thus, the Coriolis force F and the acceleration G due to the angular velocity Ω act on the second vibrating body 8.

For this reason, as shown in FIG. 5, when acceleration G is applied to the right along the Y-axis direction and the second vibrating body 8 is displaced to the left by Coriolis force F,
In the displacement detector 18L on the left side of the connecting portion 8B, the electrode plate 15
The separation dimension d0 between B and 16B is the displacement dimension of the acceleration G (−Δdc0) in addition to the displacement dimension (−Δdc0) due to the Coriolis force F.
g0) and (−Δdc0−Δdg0). For this reason,
The displacement detector 18L on the left side has a displacement capacity (+ ΔCc0) due to the Coriolis force F and a displacement capacity (+ ΔCg0) due to the acceleration G.
And outputs a displacement signal of the displacement capacity (+ ΔCc0 + ΔCg0).

Here, the displacement size (-Δdg0) means that the second vibrating body 8 is displaced by the acceleration G, and the electrode plate 15B,
It shows the change in the separation dimension when the separation dimension between 16B is reduced with respect to the initial separation dimension d0. The displacement capacity (+ ΔCg0) means that the distance between the electrode plates 15B and 16B is reduced by the displacement size (−Δdg0),
The figure shows a change in the capacitance when the capacitance between B and 16B increases with respect to the initial capacitance C0.

On the other hand, the displacement detector 18 on the right side of the connecting portion 8B
In R, the distance d0 between the electrode plates 15B and 16B is determined by the acceleration G in addition to the displacement (+ Δdc0) due to the Coriolis force F.
Larger by the displacement dimension (+ Δdg0) of (+ Δdc0 + Δdg)
0). For this reason, the displacement detector 18R on the right side calculates the displacement capacity (−ΔCc0−) obtained by adding the displacement capacity (−ΔCc0) due to the Coriolis force F and the displacement capacity (−ΔCg0) due to the acceleration G.
ΔCg0) is output. That is, acceleration G toward the right along the Y-axis direction is applied, and the second vibrating body 8
Is displaced to the left by the Coriolis force F, the displacement dimensions and displacement capacities of the left and right displacement detectors 18L and 18R are as shown in Table 2 below.

Here, the displacement size (+ Δdg0) means that the second vibrating body 8 is displaced by the acceleration G, and the electrode plate 15B,
It shows a change in the separation dimension when the separation dimension between 16B is increased with respect to the initial separation dimension d0. The displacement capacity (−ΔCg0) means that the distance between the electrode plates 15B and 16B increases by the displacement size (+ Δdg0),
The figure shows a change in the capacitance when the capacitance between B and 16B decreases with respect to the initial capacitance C0.

[0073]

[Table 2]

When the displacement signal from the right displacement detector 18R is subtracted from the displacement signal from the left displacement detector 18L as shown in the following equation (4), (2 × ΔCc0 + 2)
× ΔCg0) is detected.

[0075]

(2 × ΔCc0 + 2 × ΔCg0) = + ΔCc0 + ΔC
g0 − (− ΔCc0−ΔCg0)

For this reason, the displacement signals output from the displacement detectors 18L and 18R include a displacement signal (2 × ΔCc0) based on the angular velocity Ω and a displacement signal (2 × ΔCg) based on the acceleration G.
0) is added as noise.

On the other hand, for the acceleration detecting element 19, Y
Since the axial acceleration G acts, the third vibrating body 22 is displaced to the left by the acceleration G by a displacement dimension Δ as shown in FIG.
Displaced by dg0. Therefore, when the third vibrating body 22 is displaced to the left due to the acceleration G, the distance d0 between the electrode plates 25B and 26B is reduced by the displacement (-Δdg0) in the displacement detector 27L on the left side of the connecting portion 22B. Become. At this time, the left displacement detection unit 27L outputs a displacement signal of the displacement capacitance (+ ΔCg0).

On the other hand, the displacement detector 2 on the right side of the connecting portion 22B
In No. 7, the separation dimension d0 between the electrode plates 25B and 26B is increased by the displacement dimension (+ Δdg0). At this time, the right displacement detection unit 27R outputs a displacement signal of the displacement capacity (−ΔCg0). That is, when the acceleration G to the right is applied, the displacement dimensions of the left and right displacement detectors 27L and 27R,
The displacement capacity is as shown in Table 3 below.

[0079]

[Table 3]

Therefore, when the displacement signal from the right displacement detection unit 27R is subtracted from the displacement signal from the left displacement detection unit 27L as shown in the following equation (5), a displacement signal of (2 × ΔCg0) can be detected.

[0081]

(2 × ΔCg0) = + ΔCg0 − (− ΔCg0)

Therefore, the first displacement detectors 18L, 18L
The displacement signal obtained by subtracting the displacement signal of R (2 × ΔCc0 + 2 × Δ
The displacement signal (2 × ΔCg0) based on the acceleration G is obtained by subtracting the displacement signal (2 × ΔCg0) obtained by subtracting the displacement signals of the second displacement detection units 27L and 27R from Cg0) as shown in the following Expression 6. Thus, only the displacement signal (2 × ΔCc0) based on the angular velocity Ω can be taken out.

[0083]

(2 × ΔCc0) = (2 × ΔCc0 + 2 × ΔCg0)
− (2 × ΔCg0)

As a result, only the displacement signal based on the angular velocity Ω can be extracted without being affected by the acceleration G applied in the Y-axis direction, and the detection accuracy of the angular velocity Ω can be improved.

Although the case where the second vibrating body 8 is displaced to the left by the Coriolis force F of the angular velocity Ω has been described, even when the second vibrating body 8 is displaced to the right by the Coriolis force F, In substantially the same manner, in the left and right displacement detectors 18L and 18R, displacement capacities (−ΔCc0 + ΔCg0) and (+ ΔCc0−ΔCg0) based on the angular velocity Ω and the acceleration G.
And the displacement detectors 27L and 27R on the left and right sides displace the displacements (+ ΔCg0) and (−ΔCg) based on the acceleration G.
g0) only.

Accordingly, the left and right displacement detectors 18L, 18L,
Displacement signal obtained by subtracting the displacement signal of 18R ｛2 × (−ΔCc
0) From + 2 × ΔCg0}, the second displacement detection units 27L, 27
The displacement signal (2 × ΔCg0) based on the acceleration G is canceled by subtracting the displacement signal (2 × ΔCg0) obtained by subtracting the displacement signal of R as shown in the following Expression 7, and the displacement signal ｛2 based on the angular velocity Ω. × (−ΔCc0)｝ alone can be extracted.

[0087]

(7) {2 × (−ΔCc0)} = {2 × (−ΔCc0) +
2 × ΔCg0｝-(2 × ΔCg0)

Thus, in the present embodiment, the first displacement detection for detecting the displacement capacity in the Y-axis direction generated in the second vibrating body 8 when the angular velocity Ω is applied to the substrate 2 around the Z-axis. Parts 18L and 18R, and second displacement detectors 27L and 27R for detecting displacement capacitance in the Y-axis direction generated in the third vibrator 22 when acceleration G is applied in the Y-axis direction. Thus, the displacement capacity of the second vibrating body 8 caused by the acceleration G can be calculated using the displacement capacity of the third vibrating body 22 detected by the displacement detecting units 27L and 27R.

For this reason, in addition to the second vibrating body 8 being displaced by the angular velocity Ω, the second vibrating body 8 is displaced by the acceleration G, and the displacement capacitance detected by the first displacement detectors 18L and 18R becomes the displacement capacitance by the angular velocity Ω. And the displacement displacement caused by the acceleration G, the second displacement detection units 27L and 27R
By using the displacement capacitance detected by the first and second displacement detection units 18L and 18R, the displacement capacitance due to the acceleration G can be offset among the displacement capacitances detected by the first displacement detection units 18L and 18R. Thereby, the detection sensitivity of the angular velocity Ω can be improved.

The third support beam 21 has a spring constant substantially equal to the spring constant of the second support beam 7, and the third vibrator 22 has a mass substantially equal to that of the second vibrator 8. Therefore, when the acceleration G is applied in the direction of the Y axis, the second vibrating body 8 and the third vibrating body 22 are displaced by substantially equal amounts. For this reason, the second displacement detectors 27L and 27R
By detecting the displacement capacity of the third vibrating body 22, the displacement capacity when the second vibrating body 8 is displaced by the acceleration G can be obtained. For this reason, the displacement capacity due to the acceleration G among the displacement capacities detected by the first displacement detection units 18L and 18R can be easily canceled without performing various calculations.

In the embodiment, the fixed-side vibrating electrode 1
Although the case where the number of the electrode plates 12A of the second 2 is six and the number of the electrode plates 13A of the movable-side vibrating electrode 13 are seven is illustrated, the invention is not limited thereto.
The number of sheets may be seven or more. By increasing the number of sheets, the driving force generated by the vibration generating section 17 can be increased.

In the embodiment, the fixed-side detection electrode 1
Although the case where the number of the electrode plates 15B and 25B of 5, 25 is six and the number of the electrode plates 16B and 26B of the movable detection electrodes 16 and 26 are six is exemplified, the present invention is not limited to this, and may be eight or more.
By increasing the number, the displacement detection units 18L and 27L
The detection sensitivity at (18R, 27R) can be increased.

[0093]

As described above in detail, according to the first aspect of the present invention, the displacement of the second vibrating body in the second axial direction is detected and applied to the substrate around the third axis. An angular velocity detecting element for detecting an angular velocity is provided, and an acceleration detecting element for detecting an acceleration applied in a second axial direction at a position different from the angular velocity detecting element is provided. Thus, even when the acceleration is applied to the entire sensor and the second vibrating body is displaced by the acceleration, the displacement amount of the second vibrating body due to the acceleration can be detected by the acceleration detecting element. Therefore, by using the signal output from the acceleration detecting element, the signal output from the angular velocity detecting element can be canceled by the acceleration, and the detection sensitivity of the angular velocity can be improved.

According to the second aspect of the present invention, the third support beam has a spring constant substantially equal to the spring constant of the second support beam, and the third vibrator is the second vibrator. , The second vibrating body and the third vibrating body are displaced by substantially equal amounts when acceleration is applied in the second axial direction. Therefore, the displacement of the third vibrating body can be detected by the acceleration detecting means, and the amount of displacement of the second vibrating body due to the acceleration can be detected. Therefore, the displacements detected by the angular velocity detecting means due to the acceleration can be easily canceled without performing various calculations.

[Brief description of the drawings]

FIG. 1 is a front view showing an angular velocity sensor according to an embodiment.

FIG. 2 is a longitudinal sectional view as seen from the direction of arrows II-II in FIG.

FIG. 3 is an enlarged front view showing a state of a second vibrating body and the like at an initial stage.

FIG. 4 is an enlarged front view showing a state of a second vibrating body and the like when an angular velocity Ω is applied around the Z axis.

FIG. 5 is an enlarged front view showing a state of a second vibrating body and the like when an angular velocity Ω is applied around the Z axis and an acceleration G is applied in the Y axis direction.

FIG. 6 is an enlarged front view showing a state of a third vibrating body and the like when an acceleration G is applied in a Y-axis direction.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Angular velocity sensor 2 Substrate 3 Angular velocity detecting element 5 First supporting beam 6 First vibrating body 7 Second supporting beam 8 Second vibrating body 18L, 18R First displacement detecting unit (angular velocity detecting means) 19 Acceleration detection Element 21 Third support beam 22 Third vibrator 27L, 27R Second displacement detector (acceleration detector)

 ──────────────────────────────────────────────────の Continued on the front page (72) Inventor Shogo Yoshino 2-26-10 Tenjin, Nagaokakyo-shi, Kyoto Inside Murata Manufacturing Co., Ltd. (72) Kaneo Yachi 2-26-10 Tenjin, Nagaokakyo-shi, Kyoto F-term in Murata Manufacturing Co., Ltd. (reference) 2F105 BB02 BB03 BB07 BB14 BB17 CC04 CD03 CD05 CD13

Claims (2)

[Claims] 1. An angular velocity detecting element provided on the substrate and detecting an angular velocity applied around a third axis perpendicular to a first axis and a second axis perpendicular to a horizontal direction of the substrate and perpendicular to the substrate. A first support beam supported on the substrate by a first support beam and oscillating in a direction of a first axis.
A vibrating body, a second vibrating body supported by the first vibrating body by a second support beam, and capable of vibrating in the directions of the first and second axes, and the first vibration Vibration generating means for vibrating the body in the direction of the first axis; and angular velocity about the third axis in a state where the vibration generating means applies vibration to the first vibrating body in the direction of the first axis. An angular velocity sensor configured to detect a displacement of the second vibrating body in a second axial direction when a vibration is applied, wherein the substrate has a second shaft at a position different from an angular velocity detecting element. An acceleration detection element for detecting an acceleration applied in the direction of: a third vibrator supported by a third support beam and capable of vibrating in a direction of a second axis; A third axial change in the third vibrating body when acceleration is applied in the second direction. An angular velocity sensor characterized by being configured by an acceleration detecting means for detecting. 2. The third support beam has a spring constant substantially equal to a spring constant of the second support beam, and the third vibrator has a mass substantially equal to the second vibrator. The angular velocity sensor according to claim 1, comprising: