JP2003202226A - External force measuring device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To stabilize a vibration condition of a mass part and improve detection precision and reliability by providing a twist connection part between a support beam and the mass part. <P>SOLUTION: The mass parts 3, 5 at the center and both side mass parts 7 composed of the mass parts 4, 6 are mutually connected by the outer side support beam 8. A node part 8A corresponding to a node when the mass parts 3, 5 and both side mass parts 7 among the support beam 8 vibrate in reverse phase is fixed to a basic plate 2 by a fixing part 13. The mass parts 3, 4 are displaced in the direction of Y-axis in accordance with angular velocity Ωaround Z-axis while the mass parts 3 to 6 vibrate in the direction of X-axis to detect its displacement amount as angular velocity. Moreover, the twist connection part 10 which is bent and deformed so as to twist around Z-axis is provided between the mass part 6 and the support beam 8. Consequently, it is possible to prevent the displacement of both side mass parts 7 in the direction of Y-axis by bending and deformation of the support beam 8 irrespective of angular velocity to increase detection precision when both side mass parts 7 vibrate in the direction of X-axis. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an external force measuring device preferably used for detecting an external force such as an angular velocity and an acceleration.

[0002]

2. Description of the Related Art Generally, as an external force measuring apparatus, a substrate, a mass portion supported by the substrate via a support beam so as to be displaceable in two directions orthogonal to each other, and the mass portion in the two directions. There is known an angular velocity sensor composed of a vibration generating means for vibrating in a vibration direction parallel to the above, and an external force detecting means for detecting a displacement amount as an angular velocity when the mass portion is displaced in a detection direction orthogonal to the vibration direction. (For example, Japanese Patent Laid-Open No. 5-321576).

An angular velocity sensor of this type according to the prior art is
Of the X axis parallel to the substrate and the Z axis perpendicular to the Y axis, for example, the mass portion is vibrated with a predetermined amplitude along the X axis direction,
If an angular velocity around the Z axis is applied in this state, Y
A Coriolis force acts in the axial direction. As a result, the mass portion is displaced in the Y-axis direction, so that the external force detecting means outputs a detection signal according to the angular velocity by detecting the displacement amount of the mass portion at this time as a change in capacitance or the like. Is.

In this case, the mass portion is supported by a support beam provided on the substrate so that it can be displaced (vibrated) in the X-axis direction or the like. This support beam has a structure in which the base end side is fixed to the substrate, the tip end side is connected to the mass part, and the mass beam vibrates in the X-axis direction when the angular velocity sensor is activated and the support beam is flexibly deformed. Has become.

[0005]

By the way, in the above-mentioned prior art, since the mass portion is connected to the substrate through the supporting beam, when the mass portion vibrates on the substrate, the vibration is transmitted through the supporting beam. Easily transmitted to the substrate side.

Therefore, when the angular velocity sensor operates, the vibration energy leaks to the substrate side, so that the amplitude of the mass portion, the vibration velocity, etc. are reduced, the Coriolis force due to the angular velocity is reduced, and the detection sensitivity may become unstable. There is. Also,
When the vibration is transmitted to the substrate side, the mass portion may vibrate in the Y-axis direction (detection direction) due to the vibration of the substrate, even though the angular velocity is not applied. Therefore, an error is likely to occur in the detected value of the angular velocity. Therefore, there is a problem that reliability is lowered.

Further, when the mass portion vibrates through the support beam, the support beam flexes and deforms, so that the mass portion Y
Since it may be displaced in the axial direction or may be inclined so as to be twisted around the Z axis, noise or the like is likely to occur in the angular velocity detection signal due to these displacements, and there is also a problem that the detection accuracy is reduced.

The present invention has been made in view of the above-mentioned problems of the prior art, and an object of the present invention is to make it possible to vibrate the mass portion in a stable manner against bending deformation of the support beam, and the vibration causes the substrate to vibrate. Another object of the present invention is to provide an external force measuring device capable of preventing transmission to the side and improving detection accuracy and reliability.

[0009]

In order to solve the above-mentioned problems, the invention of claim 1 is directed to a substrate and a three-axis direction consisting of an X-axis, a Y-axis and a Z-axis which face the substrate with a gap and are orthogonal to each other. Among them, a plurality of mass parts arranged side by side in the Y-axis direction, support beams extending in the Y-axis direction that are flexibly deformable on both sides in the X-axis direction across the mass parts, and the mass parts. An intermediate connecting part for connecting between the intermediate mass part located at an intermediate part in the Y-axis direction and the support beam, both side mass parts located on both sides of the mass part in the Y-axis direction, and the support beam. Of the mass portions, and a torsional coupling portion that couples and the torsion beam around the Z-axis in a state capable of being twisted, a fixing portion that is provided between the substrate and the support beam and that fixes the support beam to the substrate, By vibrating at least a part of the mass parts, the mass parts adjacent to each other are in the opposite phase and in the X-axis direction. The vibration generating means vibrates in a horizontal direction and the external force detecting means for detecting the displacement amount of the mass portion displaced in the Y-axis direction as the angular velocity or the acceleration when the angular velocity or the acceleration acts on each mass portion. There is.

With this structure, the mass beams adjacent to each other can vibrate in the X-axis direction in opposite phases due to the bending deformation of the support beams, and the external force detecting means can maintain the mass parts in this state. It is possible to detect the amount of displacement when is displaced in the Y-axis direction as angular velocity or acceleration.
In this case, a vibration node that holds a substantially constant position when the mass part vibrates in the opposite phase can be arranged at an intermediate part of the support beam, so that, for example, the part corresponding to this node is fixed to the substrate by the fixing part or the like. can do.

Further, when each mass portion vibrates, the torsional coupling portion interposed between the support beam and the mass portions on both sides is flexibly deformed so as to be twisted about the Z axis with respect to the support beam, and the support beam is then deformed. Since the bending deformation of the support beam can be compensated for, the mass parts on both sides can be vibrated substantially parallel to each other along the X-axis direction, and these can be prevented from being displaced in the Y-axis direction by the bending deformation of the support beam regardless of the external force. You can

Further, according to the second aspect of the present invention, the both side mass parts have side faces facing the support beam with a gap in the X-axis direction interposed therebetween, and the torsional connecting part connects the both side mass parts to one of the side faces.
It is designed to be supported at some points.

Thus, when the support beam is flexibly deformed in the X-axis direction, the torsional connection portion can be flexibly deformed between the support beam and the both side mass parts so as to be twisted about the Z-axis with respect to both of them. The twisted connecting portion can transmit only the amount of displacement in the X-axis direction of the deformation operation (displacement) of the support beam to the mass portions on both sides, and can absorb the amount of displacement in the Y-axis direction.

According to the third aspect of the present invention, the twisted connecting portion is formed by a bent portion bent from the support beam toward the mass portions on both sides in an L shape or a crank shape.

Thus, the tip end side of the twisted connecting portion extending in the L shape or the crank shape can be connected to the both side mass portions, and the tip end side can be flexibly deformed so as to be twisted around the Z axis with respect to the support beam. You can

Further, according to the invention of claim 4, the torsional connecting portion is connected to the both side mass portions at a position outside the center of gravity of the both side mass portions in the Y-axis direction.

As a result, when the mass parts on both sides vibrate in the X-axis direction due to the bending deformation of the support beam and are to be displaced so as to twist about the Z-axis, the mass parts rotate in a direction opposite to the twisting direction. A moment can be generated, and the force for displacing the mass portions on both sides can be canceled by the rotation moment.

According to the fifth aspect of the invention, the fixing portion is configured to fix the portion of the support beam corresponding to the node when the mass portions vibrate in opposite phases to the substrate.

Thus, the fixing portion can fix the supporting beam to the substrate side at a position corresponding to a node when each mass portion vibrates, and therefore these vibrations are not transmitted to the substrate side via the supporting beam. Can be suppressed.

Further, according to the invention of claim 6, the substrate is provided with a cover plate for covering each mass part, the support beam, the intermediate connecting part, the torsion connecting part, the fixing part, the vibration generating means and the external force detecting means,
On the cover plate, a drive-side wire that supplies a drive signal to the vibration generating means, a detection-side wire that outputs a detection signal from the external force detecting means, and a drive-side wire that surrounds the detection-side wire and detects the drive-side wire. A frame-shaped ground wiring is provided at a position where it is partitioned from the side wiring, and connects the vibration generating means and the external force detecting means to the ground side.

As a result, the ground wiring can electromagnetically shield the detection-side wiring from the drive-side wiring, so that it is possible to prevent noise or the like from being generated in the detection signal due to the drive signal or the like.

Further, in the invention of claim 7, a substrate and an X-axis, a Y-axis, which face the substrate with a gap and are orthogonal to each other,
A first mass part that can vibrate in the X-axis direction out of three Z-axis directions, and a first mass part that is provided on both sides of the first mass part in the Y-axis direction and that can vibrate in the X-axis direction. Two second
, A third mass part surrounding the first mass part and supporting the first mass part so as to be displaceable in the Y-axis direction, and the second mass part. Two fourth mass parts that are provided so as to surround each of the second mass parts so as to be displaceable in the Y-axis direction, and are bent to both sides in the X-axis direction across the first to fourth mass parts. A support beam, which is deformable and has an intermediate part in the length direction connected to the third mass part, and both sides in the length direction of the support beam and the fourth mass part can be flexibly deformed around the Z axis. A flexible connecting part connected to the substrate, a fixing part provided between the substrate and the supporting beam for fixing an intermediate part in the length direction of the supporting beam to the substrate, and a mass of at least a part of the mass parts. By vibrating the section,
Vibration generating means for vibrating the third mass part and the second and fourth mass parts in the X-axis direction in opposite phases to each other, and when the angular velocity or acceleration acts on each mass part, each mass part is Y The external force detecting means detects the amount of displacement in the axial direction as angular velocity or acceleration.

[0023]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, an external force measuring device according to an embodiment of the present invention will be described in detail with reference to the accompanying drawings, taking an angular velocity sensor as an example.

In the figure, 1 is an angular velocity sensor applied to the present embodiment, 2 is a substrate constituting the main body of the angular velocity sensor 1, and the substrate 2 is made of, for example, a high resistance silicon material, glass material, or the like. Of the three axial directions, which are formed in a quadrangular shape and include the X axis, the Y axis, and the Z axis orthogonal to each other, for example, X
It extends horizontally along the axis and the Y-axis and is arranged perpendicular to the Z-axis.

Further, as shown in FIGS. 1 and 2, a low resistance silicon material which is, for example, a single crystal or a polycrystal is provided on the substrate 2 and is subjected to fine processing such as etching treatment. , A central mass part 3, an outer mass part 4, which will be described later.
Frame-shaped mass parts 5, 6, outer support beam 8, intermediate connection part 9, twist connection part 10, inner support beams 11, 12, fixed part 13, electrode support parts 14, 19, drive electrodes 15, 16, detection electrodes Two
0, 21, 22, 23, 24, 25, 26, 27 etc. are formed.

Reference numeral 3 denotes a central mass portion arranged on the central side of the substrate 2, and the central mass portion 3 is, as shown in FIGS.
Front and rear horizontal frame portions 3A that are integrally formed as a frame-like body that forms a substantially "Sun" shape and that extend in the X-axis direction, and left and right vertical frame portions 3B that extend in the Y-axis direction. The intermediate frame portion 3C is located between the horizontal frame portions 3A and extends in the X-axis direction.

Here, the central mass portion 3 includes an outer support beam 8,
An intermediate connecting portion 9, a torsion connecting portion 10, and an inner supporting beam 11,
It is connected to the outer mass part 4 and the frame-shaped mass parts 5 and 6 via 12. The mass portions 3 to 6 are supported by the outer support beam 8 so as to be displaceable (vibrated) in the X-axis direction, face the substrate 2 with a gap, and are arranged substantially linearly in the Y-axis direction. There is. Also, the central mass part 3
Are supported by an inner support beam 11 provided inside the frame-shaped mass portion 5 so as to be displaceable in the Y-axis direction.

Reference numeral 4 denotes a front portion in the Y-axis direction with the central mass portion 3 interposed therebetween,
A pair of outer mass parts provided on both sides of the rear, each outer mass part 4 comprising a quadrangular frame-shaped body having front and rear horizontal frame parts 4A and left and right vertical frame parts 4B. It is supported so as to be displaceable in the Y-axis direction by using an inner support beam 12 provided inside the cylindrical mass portion 6.

Reference numeral 5 denotes a frame-shaped mass portion provided so as to surround the central mass portion 3. The frame-shaped mass portion 5 has front and rear horizontal frame portions 5A and left and right vertical frame portions 5B. It is formed as a quadrangular frame-shaped body and is arranged between the outer mass parts 4. The frame-shaped mass portion 5 has its outer portion connected to the outer support beam 8 via the intermediate connecting portion 9, and has its inner portion connected to the central mass portion 3 via the inner support beam 11. .

Reference numeral 6 denotes a pair of frame-shaped mass portions provided so as to surround each outer mass portion 4, and each frame-shaped mass portion 6 is
The side surface 6B1 is formed as a rectangular frame having front and rear horizontal frame portions 6A and left and right vertical frame portions 6B, and the side surface 6B1 located outside each vertical frame portion 6B sandwiches a gap in the X-axis direction. And faces the outer support beam 8. The frame-shaped mass portion 6 has its outer side portion connected to the outer support beam 8 via the torsion connecting portion 10, and its inner side portion connected to the outer mass portion 4 via the inner support beam 12.

Reference numeral 7 is a both-side mass portion composed of an outer mass portion 4 and a frame-shaped mass portion 6. The both-side mass portions 7 are arranged symmetrically on both front and rear sides with the central mass portion 3 in between. The center of gravity G is arranged inside the outer mass portion 4 as shown in FIG. 4, for example.

Reference numeral 8 is, for example, two outer support beams as support beams provided on both the left and right sides in the X-axis direction with the mass portions 3, 4, 5, 6 interposed therebetween. The beam is formed as a narrow beam that flexibly deforms in the X-axis direction, linearly extends along the Y-axis direction, and supports the mass portions 3 to 6 so as to be displaceable in the X-axis direction.

When the angular velocity sensor 1 is operated, the central mass portions 3 and 5 and the both side mass portions 7 are in substantially opposite phases to each other via the outer supporting beam 8 and the like in the X-axis direction (arrow a in FIG. 1).
Vibrations in the 1 and a2 directions), and at this time, four node portions 8A, which serve as nodes for vibration and hold a substantially constant position, are formed in the middle portion of the outer support beam 8 in the length direction. .

Reference numeral 9 denotes, for example, two intermediate connecting portions which connect the longitudinal intermediate portion of each outer supporting beam 8 and the frame-shaped mass portion 5, and each intermediate connecting portion 9 is connected to the frame-shaped mass portion 5. Outside support beam 8
With respect to, the displacement in the Y-axis direction is restricted.

Reference numeral 10 denotes, for example, four twisted connecting portions as flexible connecting portions for connecting between both ends of the outer supporting beam 8 and each frame-shaped mass portion 6, and each twisted connecting portion 10 is, for example, an outer side. It is formed as an L-shaped bent portion that is slightly wider than the support beam 8, bends at a substantially right angle from the end side of the outer support beam 8 toward the frame-shaped mass portion 6, and is linear along the X-axis direction. Extends to.

The torsion connecting portion 10 has its base end side connected to the end portion side of the outer supporting beam 8 and its tip end side connected to the side surface 6B1 of the frame-shaped mass portion 6, and thereby the frame-shaped mass portion. 6 is supported at one position on the side surface 6B1. In this case, the connecting portions of the left and right torsional connecting portions 10 with respect to the frame-shaped mass portion 6 are arranged at the same position in the Y-axis direction as shown in FIG. It is arranged outside the center of gravity G of the portion 7 by a dimension d.

The torsional connecting portion 10 is formed by the outer supporting beam 8
When the mass portions 3 to 6 vibrate and deform, the outer supporting beam 8 is flexibly deformed so as to be twisted around the Z axis (inclined in the Y axis direction), and the frame-shaped mass portion 6 is also deformed. It also bends and deforms so as to twist. As a result, the torsional connection portion 10 transmits only the displacement amount in the X-axis direction of the deformation operation (displacement) of the outer support beam 8 to the frame-shaped mass portion 6, while compensating for the bending deformation in other directions. The absorption prevents the both side mass portions 7 from being displaced in the Y-axis direction due to the bending deformation of the outer support beam 8 regardless of the angular velocity.

Reference numeral 11 denotes, for example, four inner support beams provided inside the frame-shaped mass portion 5 located at the center. Each of the inner support beams 11 is formed as a narrow beam extending in the X-axis direction,
It can be flexibly deformed in the Y-axis direction. The tip end side of each inner support beam 11 is connected to the four corners of the central mass portion 3 to support the central mass portion 3 so as to be displaceable in the Y-axis direction, and the central mass portion 3 is displaced in the X-axis direction. Is regulated.

Reference numeral 12 denotes an inner support beam provided inside each frame-shaped mass portion 6, for example, four each, and each inner support beam 12 is
It is formed as a narrow beam almost similar to the inner support beam 11,
While supporting the outer mass portion 4 so as to be displaceable in the Y-axis direction,
The outer mass portion 4 is restricted from being displaced in the X-axis direction.

Reference numeral 13 designates the node portion 8A of each outer supporting beam 8 on the substrate 2
The fixing portion 13 is fixed to the mass portion 3, 4,
A pedestal portion 13A having a rectangular shape fixed on the substrate 2 at a position surrounding 5, 6 and the like, and a node of each outer support beam 8 formed integrally with the pedestal portion 13A inside the pedestal portion 13A and at a position distant from the substrate 2. Part 8
It is constituted by, for example, four arm portions 13B each connected to A. Then, when the central mass portions 3 and 5 and both side mass portions 7 vibrate in opposite phases, these vibrations cancel each other out at the positions of the respective node portions 8A,
The fixing portion 13 suppresses the transmission of vibration to the substrate 2.

On the other hand, 14 is, for example, four drive electrode support portions provided on the substrate 2 on the front and rear sides of each frame-shaped mass portion 6, and 15 is each drive electrode support portion 14. Each of the fixed side drive electrodes is provided with the fixed side drive electrode 15.
Has a plurality of electrode plates 15A protruding in the X-axis direction and arranged in a comb-teeth shape at intervals in the Y-axis direction.

Reference numeral 16 is a position corresponding to each drive electrode support portion 14, and is provided on the lateral frame portion 6A of the frame-shaped mass portion 6 so as to project, for example, 4
Each movable side drive electrode 16 has a plurality of electrode plates 16A that mesh with each electrode plate 15A of the fixed side drive electrode 15 with a gap in the Y-axis direction interposed therebetween.

Reference numeral 17 denotes a vibration generating section as vibration generating means composed of the drive electrodes 15 and 16. The vibration generating section 17 is provided on the drive electrode pad 18 provided on the drive electrode supporting section 14. By inputting a drive signal composed of a DC bias voltage and an AC voltage, the drive electrodes 15 and 16 are
Electrostatic attraction is generated between the frame-shaped mass portion 6 and the arrow a in FIG.
Vibrate in the 1 and a2 directions. As a result, the central mass portions 3 and 5 and both side mass portions 7 vibrate in opposite phases via the outer supporting beam 8.

Reference numeral 19 denotes, for example, four detection electrode support portions provided on the substrate 2 and located inside the mass portions 3 and 4, and inside each of the detection electrode support portions 19, the central mass portion 3 is provided. The two support portions 19 located at the
Fixed side detection electrodes 20 and 21 having 21A are provided.

Further, the fixed side detection electrode 2 having comb-teeth-shaped electrode plates 22A and 23A is provided on the two support portions 19 located inside the outer mass portion 4 among the detection electrode support portions 19.
2, 23 are provided.

Reference numerals 24 and 25 denote intermediate frame portions 3C of the central mass portion 3.
Movable side detection electrodes, 26 and 27 are movable side detection electrodes projecting inside the lateral frame portion 4A of the outer mass portion 4,
These movable side detection electrodes 24, 25, 26, 27 are the electrode plates 20A of the fixed side detection electrodes 20, 21, 22, 23,
It has a plurality of electrode plates 24A, 25A, 26A and 27A which mesh with 21A, 22A and 23A with a gap in the Y-axis direction sandwiched therebetween.

28 is a displacement amount detecting section 29, 30, 3 described later.
In the displacement amount detecting section that constitutes the external force detecting means together with 1, the displacement amount detecting section 28 is composed of a fixed side detecting electrode 20 and a movable side detecting electrode 24. The parallel plate capacitor is detected by the change of. Then, the displacement amount detection unit 28 uses the central mass unit 3
1 decreases along the Y-axis direction in the direction of the arrow b1 in FIG. 1 and decreases when the central mass portion 3 moves in the direction of the arrow b2. .

Reference numeral 29 is another displacement amount detecting portion for detecting the displacement amount of the central mass portion 3. The displacement amount detecting portion 29 is constituted by the fixed side detection electrode 21 and the movable side detection electrode 25 as a capacitor, The capacitance is set in advance so as to increase / decrease in the displacement direction of the central mass unit 3 in the opposite direction to the displacement amount detecting unit 28. That is, the displacement amount detection unit 29 has an increased capacitance when the central mass unit 3 is displaced in the direction of the arrow b1,
The capacitance is reduced when the central mass portion 3 is displaced in the direction of the arrow b2.

Reference numeral 30 denotes a displacement amount detecting portion for detecting the displacement amount of the outer mass portion 4 by the change of the electrostatic capacitance, and the displacement amount detecting portion 3
0 is composed of the fixed side detection electrode 22 and the movable side detection electrode 26, and the capacitance increases when the outer mass part 4 is displaced in the arrow b1 direction, and the outer mass part 4 moves in the arrow b2 direction. The capacitance decreases when displaced to.

Reference numeral 31 is another displacement amount detecting portion for detecting the displacement amount of the outer mass portion 4. The displacement amount detecting portion 31 is composed of a fixed side detecting electrode 23 and a movable side detecting electrode 27, which are
Contrary to the case of the displacement amount detection unit 30, the outer mass unit 4 is indicated by the arrow b.
The capacitance decreases when it is displaced in one direction, and increases when the outer mass portion 4 is displaced in the arrow b2 direction.

When the mass portions 3 to 6 are vibrating in the X-axis direction, when the angular velocity Ω about the Z-axis is applied to the substrate 2, the inner support beams 11 and 12 are flexibly deformed,
The mass parts 3 and 4 are displaced in the Y-axis direction according to the magnitude of the angular velocity Ω. As a result, the displacement amount detectors 28, 29, 30,
Reference numeral 31 indicates the amount of displacement of the mass parts 3 and 4 as a change in capacitance, and the detection electrode pad 3 provided on the support part 19
A detection signal is output from 2, 33, 34, and 35 to the outside.
In addition, the pedestal portion 13A of the fixed portion 13 is provided with a
For example, two grounding electrode pads 36 connected to 5 are provided.

On the other hand, 37 is a cover plate provided on the substrate 2,
As shown in FIGS. 2 and 5, the lid plate 37 is formed in a square shape by using, for example, a high resistance silicon material, a glass material, or the like, and the pedestal portion 13 of the fixing portion 13 is formed by means of anodic bonding or the like.
It is joined to A and the like, and covers the mass parts 3 to 6, the support beam 8, the torsion connecting part 10, the fixing part 13, the vibration generating part 17, the displacement amount detecting parts 28 to 31, and the like. In addition, the lid plate 37,
The electrode pads 18, 32 to 36 are connected to wirings 38, 40, which will be described later.
A plurality of through holes 37 </ b> A are formed to connect to 41.

Reference numeral 38 is a cover plate 3 corresponding to each vibration generator 17.
For example, four driving-side wirings are provided at four corners of the driving-side wiring 7. Each driving-side wiring 38 is formed as a wiring pattern by, for example, a metal film or the like, and each driving-side electrode is formed through the through hole 37A of the cover plate 37. It is connected to the pad 18. The drive side wiring 38 is connected to the electrode pad 1 from the external signal output circuit 39.
An AC drive signal is supplied to each vibration generating unit 17 via 8 or the like.

Reference numeral 40 denotes a detection side wiring provided on the center side of the lid plate 37 corresponding to the displacement amount detection units 28 and 30, and the detection side wiring 40 detects a displacement amount with respect to a differential amplifier 42 described later. The parts 28 and 30 are connected in parallel, and the amount of displacement of the central mass part 3 and the amount of displacement of one outer mass part 4 are added and detected.

Reference numeral 41 denotes another detection-side wiring provided on the center side of the cover plate 37. The detection-side wiring 41 connects the displacement amount detecting sections 29 and 31 to the differential amplifier 42 in parallel, The displacement amount of the mass part 3 and the displacement amount of the other outer mass part 4 are added and detected.

Then, the detection signals output from the detection side wirings 40 and 41 are input to the differential amplifier 42 after converting the capacitance change into voltage, and the differential amplifier 42
The difference between these detection signals is output to the output terminal 43 as a detection signal corresponding to the angular velocity Ω.

Reference numeral 44 denotes a frame-shaped ground wiring provided on the cover plate 37. The ground wiring 44 is provided on the movable side drive electrode 16 of the vibration generator 17 and the movable side detection electrodes 2 of the displacement amount detectors 28 to 31.
4 to 27 and ground 4 through each grounding electrode pad 36
Connected to 5.

The ground wiring 44 is connected to the detection side wiring 40,
Drive side wiring 38 and detection side wiring 40 so as to surround 41,
It is formed at a position where it is separated from 41, electrostatically shields the detection-side wirings 40 and 41 with respect to the drive-side wiring 38, and prevents noise and the like from occurring in the detection signal due to the drive signal.

The angular velocity sensor 1 according to this embodiment has the structure as described above, and its operation will be described below.

First, when AC drive signals having mutually opposite phases are applied together with a DC bias voltage from the signal output circuit 39 to the left and right vibration generators 17, the left and right fixed side drive electrodes 15 and movable electrodes 15 are movable. Electrostatic attraction is alternately generated between the side drive electrode 16 and the outer mass portion 4 and the frame-shaped mass portion 6 vibrate together in the directions a1 and a2 shown by arrows in FIG. Then, this vibration is transmitted to the frame-shaped mass portion 5 by bending and deforming each outer support beam 8 in the X-axis direction, and the central mass portion 3 and the frame-shaped mass portion 5 vibrate with respect to the both-side mass portions 7. The phase is about 18
It vibrates in the opposite phase with a 0 ° shift. At this time, the outer support beam 8
The node portion 8A becomes a node of vibration and holds a substantially constant position. Therefore, the vibration is hardly transmitted to the substrate 2 via the fixing portion 13 supporting the node portion 8A.

When the outer mass parts 4 vibrate in the X-axis direction due to the left and right outer support beams 8 flexing and deforming, the torsion connecting parts 10 form the frame-shaped mass part 6 and the outer supporting beams 8.
Between them and the elastic deformation of the outer support beam 8 such that the outer support beam 8 is deformed so as to be twisted about the Z axis.
While transmitting only the displacement amount in the axial direction to the frame-shaped mass portion 6, the bending deformation other than this direction is compensated and absorbed. As a result, it is possible to prevent the both-sides mass portion 7 from being displaced in the Y-axis direction regardless of the angular velocity due to bending deformation of the outer support beam 8 or the like.

However, since the torsional connecting portion 10 is also provided with a certain degree of rigidity, when the frame-shaped mass portion 6 vibrates in the X-axis direction, the torsional connecting portion 10 and the outer supporting beam 8 are provided with these members. A slight force acts to hold it at a right angle. Therefore, for example, when the frame-shaped mass portion 6 vibrates in the direction of the arrow a2, a rotational moment M is applied to the frame-shaped mass portion 6 due to the bending deformation of the outer support beam 8 or the like, as shown by an imaginary line in FIG. The both-sides mass portions 7 are displaced so as to be twisted around the Z axis, and there is a tendency that they are slightly displaced with respect to the parallel movement in the X axis direction.

On the other hand, in the present embodiment, the torsional connecting portion 10 is attached to the frame-shaped mass portion 6 at a position between the front and rear frame-shaped mass portions 6 outside the center of gravity G of the both-side mass portions 7. Since they are connected, an inertial force acts on the both-sides mass portion 7 with the connecting portion with the torsion connecting portion 10 serving as a fulcrum. As a result, a rotational moment M ′ in the opposite direction to the rotational moment M (the twisting direction of the frame-shaped mass portion 6) can be generated in the both side mass portions 7, and this can cancel the rotational moment M.

Similarly, when the frame-shaped mass portion 6 vibrates in the a1 direction indicated by the arrow, the rotational moment M'due to the center of gravity G is similarly generated.
Can be generated to cancel the rotational moment M due to the bending deformation of the outer support beam 8 or the like. Thus, when no angular velocity is applied to the substrate 2, the both-sides mass portions 7 can be vibrated in a stable state substantially parallel to each other along the X-axis direction, and they are prevented from being twisted and displaced. You can

Next, the angular velocity detecting operation will be described. First, when the angular velocity Ω about the Z axis is applied to the substrate 2 in a state where the mass parts 3 to 6 are vibrated, these are calculated in the Y axis direction shown in the following mathematical formula 1. Therefore, the central mass portion 3 is displaced in the Y-axis direction according to the Coriolis force F1 as the inner support beam 11 is flexibly deformed.

[0066]

[Equation 1] F1 = 2 MΩv However, M: mass of the central mass part 3 Ω: Angular velocity around the Z axis v: the velocity of the central mass part 3 in the X-axis direction

Further, since each outer mass part 4 vibrates in the opposite phase (speed in the opposite direction) to the central mass part 3, the above formula 1
As can be seen from the equation (3), the Coriolis force F2 in the direction opposite to the central mass portion 3 is received, and the inner support beam 12 is flexibly deformed and displaced in the Y-axis direction.

In this case, for example, in FIG. 6, if the central mass part 3 is displaced in the direction of arrow b1 by the Coriolis force F1 and each outer mass part 4 is displaced in the direction of arrow b2 by the Coriolis force F2, The capacitances of the quantity detection units 28 and 30 decrease, and the detection side wiring 40 outputs an added value obtained by adding these capacitance changes.

Further, since the electrostatic capacitances of the displacement amount detecting sections 29 and 31 increase, and the added value of these capacitance changes is output to the detection side wiring 41, the differential amplifier 42
By outputting the difference between the signal values input from the detection-side wirings 40 and 41, the angular velocity Ω about the Z axis applied to the substrate 2 can be detected with high accuracy due to the change in capacitance.

On the other hand, when the acceleration in the Y-axis direction is applied to the substrate 2, for example, when the acceleration in the arrow b1 direction is applied to the substrate 2, the central mass part 3 and each outer mass part 4 are put together. Since the displacement is detected in the direction of arrow b1 in FIG.
The capacitance increases at 9 and 30. Therefore, the change in capacitance due to acceleration is canceled between the displacement amount detection units 28 and 30 connected by the detection side wiring 40 and between the displacement amount detection units 29 and 31 connected by the detection side wiring 41, respectively. Therefore, it is possible to prevent the acceleration applied to the substrate 2 from being erroneously detected as an angular velocity due to an external impact or the like.

Thus, according to the present embodiment, the central mass part 3, the outer mass part 4, and the frame-shaped mass parts 5, 6 are connected by the outer support beam 8 so as to be displaceable in the X-axis direction, and the outer support beam 8 is formed. Between the frame-shaped mass part 6 and the frame-shaped mass part 6, the torsional connection part 10 bent from the outer support beam 8 into an L-shape is provided.
When the angular velocity sensor 1 is operated, the outer support beam 8 is flexibly deformed, so that the central mass portions 3 and 5 and both side mass portions 7 can be vibrated in the X-axis direction in opposite phases to each other.

When the outer supporting beam 8 is flexibly deformed, the torsional connecting portion 10 interposed between the outer supporting beam 8 and the frame-shaped mass portion 6 is twisted about both of them about the Z axis. As described above, the bending deformation can be easily performed, and only the displacement amount in the X-axis direction of the bending deformation of the outer support beam 8 can be transmitted to the frame-shaped mass portion 6 by the twist connection portion 10.

Further, since the torsion connecting portion 10 is arranged between the frame-shaped mass portions 6 and outside the center of gravity G of the both side mass portions 7,
The rotation moment M applied from the outer supporting beam 8 to the both side mass portions 7 can be canceled by the rotation moment M ′ by the center of gravity G. Therefore, even when the torsional connecting portion 10 has a certain degree of rigidity, when the outer supporting beam 8 is flexibly deformed, the both-sides mass portions 7 can be vibrated substantially in parallel along the X-axis direction.

Therefore, it is possible to reliably prevent the both-sides mass portions 7 from being displaced or twisted in the Y-axis direction regardless of the angular velocity due to the bending deformation of the outer support beam 8 or the like, and the detection signal of the angular velocity may have noise or drift. It is possible to suppress the occurrence of noise and improve the detection accuracy to improve the performance and reliability of the sensor.

Further, by vibrating the mass parts 3 and 5 and the both side mass parts 7 in opposite phases to each other, the vibration of the mass parts 3 to 6 can be canceled at the position of the node part 8A of the outer supporting beam 8. The node portion 8A can be fixed to the substrate 2 by the fixing portion 13. With this, it is possible to prevent the vibration energy of the mass parts 3 to 6 from being transferred from the fixed part 13 to the substrate 2, and to efficiently vibrate the mass parts 3 to 6 at a predetermined amplitude, vibration speed, etc. Vibration can be suppressed and detection accuracy can be made more stable.

In this case, by arranging the pair of outer mass parts 4 symmetrically with the central mass part 3 interposed therebetween, these can be vibrated in a well-balanced manner with a simple structure, and the vibrating state can be maintained well. You can Further, since the frame-shaped mass parts 5 and 6 surrounding these mass parts 3 and 4 are provided, the flexural deformation of the outer support beam 8 causes the displacement amount detection part 2 of the mass parts 3 and 4.
Transmission to 8, 29, 30, 31 can be prevented by the frame-shaped mass portions 5, 6, and the angular velocity detection accuracy can be further improved.

On the other hand, since the displacement amount detectors 28 and 30 are connected in parallel to the detection side wiring 40 and the displacement amount detection units 29 and 31 are connected in parallel to the detection side wiring 41, for example, on the substrate 2. When the acceleration in the Y-axis direction is applied, the displacement (change in capacitance) of the mass parts 3 and 4 due to this acceleration is detected between the displacement amount detecting parts 28 and 30, and the displacement amount detecting parts 29 and 31.
You can cancel each in between.

As a result, there is no need to provide a first-stage amplifier or the like for adding the detection signals of the displacement amount detecting units 29 and 31 in order to remove the acceleration component contained in the external force, and the signal processing connected to the angular velocity sensor 1 is eliminated. The circuit etc. can be simplified. Then, the acceleration component can be separated and removed from the detection signal of the angular velocity by the simple structure using the detection-side wirings 40 and 41, and the difference between the detection signals by the detection-side wirings 40 and 41 is obtained by using the differential amplifier 42. ,
The angular velocity Ω can be detected with high accuracy.

In this case, for example, the displacement amount detectors 29, 31
In the method of removing the acceleration component by converting the detection signal of (1) into an electric signal by the first-stage amplifier and then adding it, the acceleration component cannot be completely removed due to variations in gain of the first-stage amplifier. On the other hand, in the present embodiment, by connecting the displacement amount detection units 29 and 31 with the detection-side wiring 41, it is possible to eliminate the change in the capacitance itself input to the differential amplifier 42, and to complete the acceleration more completely. Can be removed.

Further, since the detection side wirings 40 and 41 are surrounded by the frame-shaped ground wiring 44, the ground wiring 44
With this, the detection-side wirings 40 and 41 can be electrostatically shielded from the drive-side wiring 38, and it is possible to prevent noise or the like from being generated in the detection signal due to an AC drive signal or the like supplied to the drive-side wiring 38. Can be detected.

In the above-mentioned embodiment, the twist connection portion 1
Although 0 is formed as an L-shaped bent portion, the present invention is not limited to this, and for example, as in the modification shown in FIG. 7, the twisted connecting portion 51 is formed in a crank shape bent at a plurality of positions in the length direction. You may comprise.

Further, in the embodiment, the angular velocity sensor 1 removes the acceleration component contained in the external force to detect only the angular velocity component, but the present invention is not limited to this.
For example, the displacement amount detection units 28 and 31 (or the displacement amount detection unit 2
The detection side wiring for acceleration that adds the detection signals of (9, 30) may be provided. As a result, when the angular velocity sensor 1 operates, the angular velocity component included in the detection signal is detected by the detection-side wiring for acceleration while the angular velocity is detected by the detection-side wiring 40, 41 (or displacement). The acceleration can also be detected by canceling it out between the quantity detecting units 29 and 30.

[0083]

As described in detail above, according to the invention of claim 1, a plurality of mass parts are connected by a support beam, and between the support beam and the mass parts on both sides, a Z-shape is provided with respect to the support beam. Since the torsional connecting portion that can be twisted about the axis is provided, each mass portion can vibrate in the X-axis direction in mutually opposite phases due to the bending deformation of the support beam. Then, when the support beam is flexibly deformed, the torsional coupling portion interposed between the support beam and both side mass parts can be flexibly deformed so as to be twisted around the Z axis, and the flexural deformation of the support beam can be prevented. Of these, only the displacement amount in the X-axis direction can be transmitted to the mass portions on both sides by the twist connection portion. Therefore, it is possible to stably vibrate the mass parts on both sides in a state substantially parallel to the X-axis direction, and to prevent them from being displaced or twisted in the Y-axis direction regardless of an external force due to bending deformation of the support beam. This can be reliably prevented, and the detection accuracy can be improved to improve reliability.

Further, according to the invention of claim 2, since the torsional connecting portion is configured to support both side mass portions at one side surface, the torsional connecting portion is deformed when the support beam is flexibly deformed in the X-axis direction. Can be flexibly deformed between the support beam and the mass parts on both sides so as to be twisted about the Z axis with respect to both of them, and the mass parts on both sides can be vibrated in parallel in a more stable state.

Further, according to the invention of claim 3, since the twisted connecting portion is formed by the bent portion bent from the support beam toward the both side mass portions in an L shape or a crank shape,
The tip side of the twisted connecting portion extending in an L shape or a crank shape can be easily bent and deformed so as to be twisted around the Z axis with respect to the support beam, and the twisted connecting portion ensures the bending deformation of the support beam. Can be absorbed into.

Further, according to the invention of claim 4, since the torsional connecting portion is connected to the both side mass portions at a position outside the center of gravity of the both side mass portions, for example, depending on the rigidity of the torsional connecting portion. Even when a rotational moment is generated in the mass parts on both sides, it is possible to generate a rotational moment in the opposite direction in these mass parts. Therefore, it is possible to cancel the rotational moment acting on the mass parts on both sides and vibrate these mass parts substantially in parallel.

Further, according to the invention of claim 5, since the fixing portion is configured to fix the portion of the support beam corresponding to the node when each mass portion vibrates to the substrate, the central mass portion and both sides are fixed. When the mass portion vibrates in opposite phases to each other, the vibration of the mass portion can be canceled at the position of the node of the support beam, and the vibration energy of the mass portion can be prevented from being transmitted from the fixed portion to the substrate side. . As a result, the mass portion can be efficiently vibrated at a predetermined amplitude, vibration speed, etc.
It is possible to suppress the vibration of the substrate and make the detection accuracy more stable.

Further, according to the invention of claim 6, on the cover plate of the substrate, the drive side wiring for supplying the drive signal to the vibration generating means, the detection side wiring for outputting the detection signal from the external force detecting means, Since the frame-shaped ground wiring that separates the detection-side wiring from the drive-side wiring is provided, the detection-side wiring can be electrostatically shielded from the drive-side wiring by the frame-shaped ground wiring and is supplied to the drive-side wiring. It is possible to prevent noise or the like from being generated in the detection signal due to the AC drive signal or the like that changes the AC signal, and to accurately detect the external force.

Further, according to the invention of claim 7, the first to fourth mass parts are connected by a support beam, and the support beam and the fourth mass part are flexibly connected to each other about the Z axis. Since it is configured to be flexibly deformable, it is possible to symmetrically arrange the second and fourth mass parts on both sides of the centrally located first and third mass parts, and to vibrate them in opposite phases with good balance. Can be made. When the support beam is flexibly deformed, the flexure connecting portion interposed between the support beam and the fourth mass part can be flexibly deformed around the Z axis. The part can be vibrated stably in a state substantially parallel to the X-axis direction, and the detection accuracy can be improved.

[Brief description of drawings]

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

FIG. 2 is a cross-sectional view of the angular velocity sensor seen from the direction of arrows II-II in FIG.

FIG. 3 is a partially enlarged plan view showing an enlarged part of the angular velocity sensor.

FIG. 4 is an enlarged view of an essential part showing an outer mass part and the like in FIG. 3 in an enlarged manner.

FIG. 5 is a circuit configuration diagram showing drive-side wiring, detection-side wiring, and ground wiring of the lid plate together with an external circuit.

FIG. 6 is a schematic explanatory view showing a state in which a central mass portion and an outer mass portion vibrate in opposite phases.

FIG. 7 is an enlarged view of a main part of an angular velocity sensor according to a modified example of the present invention viewed from the same position as in FIG.

[Explanation of symbols]

1 Angular velocity sensor 2 Substrate 3 Central mass part 3A, 3B, 3C Frame part 4 Outer mass part 4A, 4B Frame part 5 Frame mass part 5A, 5B Frame part 6 Frame mass part 6A, 6B Frame part 6A1 Side surface 7 Both sides mass Part 8 Outer support beam (support beam) 8A Node part 9 Intermediate connection part 10,51 Twist connection part (flexible connection part) 11,12 Inner support beam 13 Fixed part 13A Pedestal part 13B Arm part 14 Drive electrode support part 15 Fixed Side drive electrodes 15A, 16A, 20A, 21A, 22A, 23A, 2
4A, 25A, 26A, 27A Electrode plate 16 Movable side drive electrode 17 Vibration generator (vibration generator) 18 Drive electrode pad 19 Detection electrode support 20, 21, 22, 23 Fixed side detection electrode 24, 25, 26 , 27 movable side detection electrodes 28, 29, 30, 31 displacement amount detection section (external force detection means) 32, 33, 34, 35 detection electrode pad 36 grounding electrode pad 37 cover plate 37A through hole 38 drive side wiring 39 signal Output circuits 40, 41 Detection side wiring 42 Differential amplifier 43 Output terminal 44 Ground wiring 45 Ground

Claims (7)

[Claims] 1. A substrate and X-axis and Y, which face the substrate with a gap and are orthogonal to each other.
A plurality of mass parts arranged side by side in the Y-axis direction out of the three axis directions consisting of the axis and the Z-axis, and extending in the Y-axis direction provided flexibly deformable on both sides in the X-axis direction with the mass parts sandwiched therebetween. A support beam, an intermediate connecting portion that connects between the support beam and an intermediate mass portion located in an intermediate portion in the Y-axis direction of each of the mass portions, and on both sides in the Y-axis direction of each of the mass portions. A torsional coupling part for coupling between the positioned both side mass parts and the support beam in a twistable state around the Z axis; and a fixing provided between the substrate and the support beam for fixing the support beam to the substrate. And a vibration generating means for vibrating at least some of the mass parts to vibrate adjacent mass parts in the X-axis direction in opposite phases by vibrating at least part of the mass parts, and angular velocity or acceleration acts on each mass part. The displacement amount that the mass part is displaced in the Y-axis direction when Force measuring device comprising constituted by the external force detecting means for detecting as. 2. The both side mass parts are X with respect to the support beam.
The external force measuring device according to claim 1, wherein the external force measuring device has side surfaces facing each other with a gap in the axial direction interposed therebetween, and the twisted connecting portion supports the both side mass portions at one location on the side surface. 3. The external force measuring device according to claim 1, wherein the twisted connecting portion is formed by a bent portion that is bent in an L shape or a crank shape from the support beam toward both side mass portions. 4. The external force measurement according to claim 1, wherein the twisted connecting portion is connected to the both side mass portions at a position outside the center of gravity of the both side mass portions in the Y-axis direction. apparatus. 5. The fixing portion is configured to fix a portion of the support beam corresponding to a node when the respective mass portions vibrate in opposite phases to the substrate. External force measuring device described. 6. The mass member, a support beam, and
A cover plate for covering the intermediate connecting portion, the twist connecting portion, the fixing portion, the vibration generating means and the external force detecting means is provided, and the cover side has a drive side wiring for supplying a drive signal to the vibration generating means, and the external force detecting means. And a detection side wiring for outputting a detection signal from the detection side wiring, and the vibration generation means and the external force detection means connected to the ground side at a position surrounding the detection side wiring and separating the drive side wiring and the detection side wiring. The external force measuring device according to claim 1, 2, 3, 4, or 5, further comprising: 7. A substrate, and X-axis and Y-axis which face the substrate with a gap and are orthogonal to each other.
A first mass part that can vibrate in the X-axis direction out of the three axis directions consisting of the Z-axis and the Z-axis, and can vibrate in the X-axis direction provided on both sides in the Y-axis direction across the first mass part. And two third mass parts that surround the first mass part and that support the first mass part so as to be displaceable in the Y-axis direction; Two fourth masses provided so as to surround the second mass parts and movably support the respective second mass parts in the Y-axis direction.
And the first to fourth mass parts are sandwiched therebetween so as to be flexibly deformable on both sides in the X-axis direction, and an intermediate portion in the longitudinal direction is the third part.
A support beam connected to the mass part of the support beam, a flexural connection part connecting both sides of the support beam in the length direction and the fourth mass part so as to be flexibly deformable about the Z axis, and the substrate and the support beam. A fixing portion provided between the fixing portions for fixing an intermediate portion in the length direction of the support beam to the substrate, and the first and third mass portions by vibrating at least a part of the mass portions. A vibration generating means for vibrating the second and fourth mass parts in opposite phases to each other in the X-axis direction, and each mass part being displaced in the Y-axis direction when an angular velocity or acceleration acts on each mass part. An external force measuring device comprising an external force detecting means for detecting a displacement amount as an angular velocity or an acceleration.