JPH1144541A - Angular velocity sensor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve accuracy in angular velocity detection by converting a displacement signal generated by a detection means for detecting y-direction displacement of a second movable body into an angular velocity signal. SOLUTION: In order to make a float react with angular velocity around a Z-axis, a first float 2 is excited only in an x-direction, a second float 3 is made to be able to vibrate only in a y-direction to obtain an angular velocity corresponding signal, and the first float 2 and the second float 3 are coupled via a third float I. The third float I is movable in x- and y-directions with respect to a substrate 1, only in the y-direction with respect to the first float 2, and only in the x-direction with respect to the second float 3. Since the first float 2 is substantially immobile in the y-direction, it may not be displaced substantially in the y-direction even if driving force in the y-direction for example is applied due to x-direction excitation driving, while the third float I and the second float 3 are not driven in the y-direction by the x-direction excitation driving and may not shift a displacement signal when no angular velocity is applied. Thus accuracy in angular velocity detection is improved.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an angular velocity sensor having a vibrating body floatingly supported on a substrate.
Although not intended to be limited to this, the present invention relates to an angular velocity sensor that electrically attracts / releases a floating semiconductor thin film formed by using a semiconductor microfabrication technique with a comb-shaped electrode and excites the x-direction.

[0002]

2. Description of the Related Art A typical type of angular velocity sensor has a pair of floating comb electrodes (a left floating comb electrode and a right floating comb electrode) on the left side and one set on the right side of a floating thin film. And two sets of fixed comb electrodes (a left fixed comb electrode and a right fixed comb electrode that mesh with and are parallel to each set of floating comb electrodes in a non-contact manner) as left floating comb electrodes / left fixed comb electrodes. By alternately applying a voltage between the space and the right floating comb electrode / the right fixed comb electrode, the floating thin film vibrates in the x direction. When an angular velocity of rotation about the z-axis is applied to the floating thin film, Coriolis force is applied to the floating thin film, and the floating thin film becomes
An elliptical vibration that vibrates also in the y direction. If the floating thin film is used as a conductor or an electrode is bonded, and a detection electrode parallel to the xz plane of the floating thin film is provided on the substrate, the capacitance between the detection electrode and the floating thin film becomes elliptical oscillation. Vibrates according to the y component (angular velocity component). By measuring the change (amplitude) of the capacitance, the angular velocity can be determined (for example, Japanese Patent Application Laid-Open Nos. 9-127148, 9-42973, 8-152327, and 5). -248882, Japanese Patent Application No. 8-249.
No. 822, Japanese Patent Application No. 9-121989, Japanese Patent Application No. 9-16
No. 3851).

Conventionally, in an angular velocity sensor of this type using a semiconductor thin film as a floating body (floating thin film), the floating body is driven by electrostatic drive in the x direction parallel to the substrate or displacement is detected by capacitance. , A comb-toothed electrode or a parallel plate electrode that meshes alternately is used, and these electrodes use a surface (xz surface) obtained by etching a semiconductor thin film.

[0004]

The floating body needs to be movable in the x-direction and the y-direction from the principle of angular velocity detection.
Therefore, conventionally, the floating body is movable in both the x and y directions and is supported by the substrate. By the way, the driving of the floating body in the x direction is performed by a parallel plate electrode (floating comb electrode / fixed comb tooth electrode) extending in the x direction, and this parallel plate electrode gives a suction force to the floating body in the y direction. easy. That is, one (one tooth) floating comb-teeth electrode extending in the x direction is defined as x
Since the two (two-tooth) fixed comb-teeth electrodes extending in the direction are sandwiched with a gap therebetween, when the one floating comb-teeth electrode is correctly positioned at the intermediate point between the two fixed comb-teeth electrodes, Since the two fixed comb-teeth electrodes exert an electrostatic attraction force in the y-direction having the same absolute value and opposite directions to the one floating comb-teeth electrode, the fixed comb-teeth electrode is applied to the floating comb-teeth electrode. No driving force is applied in the y direction. However, if the one floating comb electrode is slightly displaced toward one of the fixed comb electrodes from the midpoint of the two fixed comb electrodes, the floating body is subjected to an angular velocity about the z-axis. Even if it is not, a driving force in the y direction is applied from the fixed comb electrode to the floating comb electrode, and the floating body is displaced in the y direction.

Since the floating body is displaced in the same cycle as the displacement of the floating body when the angular velocity is applied, it causes an offset that generates a detection signal similar to the presence of the angular velocity even when the angular velocity is not applied. In addition, it causes offset fluctuation (temperature drift) due to temperature, and tends to cause a decrease in angular velocity detection accuracy.

Further, since the floating body is movable in the x and y planes, the spring constant in the z direction of the supporting structure of the floating body with respect to the substrate is likely to be small, and the floating body is displaced in the z direction with respect to the acceleration in the z direction. The relative position of the floating comb-teeth electrode relative to the fixed comb-teeth electrode in the z direction shifts, and the capacitance between the two electrodes changes. This change in capacitance becomes a disturbance to the detection of angular velocity around the z-axis. Therefore, it is preferable to suppress the displacement of the floating body in the z direction due to the application of the acceleration in the z direction.

SUMMARY OF THE INVENTION It is an object of the present invention to increase the angular velocity detection accuracy. More specifically, the angular velocity signal deviation when the angular velocity is not applied and the level change of the angular velocity signal due to the addition of the acceleration in the z direction Are to be suppressed together.

[0008]

[Means for Solving the Problems]

(1) The angular velocity sensor according to the present invention comprises a substrate (1);
A first movable body (2) supported movably in the direction and substantially immovable in the y direction; a first movable body (2) supported in the substrate (1) in the y direction and substantially immovable in the x direction. 2 movable body (3); movable in the x and y directions, coupled to the first movable body (2) in the y direction and substantially immovably in the x direction,
Exciting means (4) for oscillatingly driving the third movable body (I) and the first movable body (2) in the x direction, which is connected to (3) movably in the x direction and substantially immovable in the y direction. , 5,15); Displacement detecting means (6a, 6b, 7a, 7b, 12,13,1) for detecting the y-direction displacement of the second movable body (3)
7); and conversion means (18) for converting a displacement signal generated by the displacement detection means into an angular velocity signal.

To facilitate understanding, symbols in parentheses are given to the reference numerals corresponding to the corresponding elements or corresponding members of the embodiment shown in the drawings and described later for reference.

When the excitation means (4, 5, 15) drives the first movable body (2) to vibrate in the x direction, the third movable body is moved together with the first movable body (2).
(I) vibrates in the x direction. When an angular velocity about the z axis is applied, the first movable body (2) does not substantially vibrate in the y direction, but the third movable body (I) also vibrates in the y direction. As a result, the second movable body (3) vibrates in the y direction, and the displacement detecting means (6a, 6b, 7a, 7b,
12, 13, 17) generate a displacement signal representing the y-direction displacement of the second movable body (3), and the converting means (18) converts the signal into an angular velocity signal.

In order to make the floating body react to the angular velocity around the z-axis, the first movable body (2) is excited only in the x direction, and the second movable body (3) for obtaining an angular velocity corresponding signal is provided only in the y direction. The first movable body (2) and the second movable body (3) are connected to a third movable body.
(I), the third movable body (I) is movable in the x and y directions with respect to the substrate (1), and y is movable with respect to the first movable body (2).
The second movable body (3) is movable only in the x direction only in the direction, and the first movable body (2) is substantially immovable in the y direction. The third movable body is not substantially displaced in the y direction even if a driving force in the
(I) and the second movable body (3) are therefore not driven in the y-direction by the x-direction excitation drive, and do not bias the displacement signal when no angular velocity is applied. This increases the angular velocity detection accuracy.

The third movable body (I) vibrates in the x direction by reliably transmitting the driving force in the x direction applied to the first movable body (3), and also vibrates in the y direction when an angular velocity about the z axis is applied. Then, the y-direction vibration is reliably transmitted to the second movable body (3). Second movable body (3)
However, since it is movable in the y-direction but substantially immovable in the x-direction, it is supported by the substrate (1), so that the spring constant of the second movable body (3) is increased by this support structure, and the second vibration Body (3)
, The displacement in the z direction due to the acceleration in the z direction is reduced, and the S / N ratio is improved.

[0013]

BEST MODE FOR CARRYING OUT THE INVENTION

(2) The first movable body (2) and the third movable body (I) have a rectangular ring shape on the x, y plane, and the third movable body (I) is provided in the inner space of the first movable body (2). , The second movable body in the inner space of the third movable body (I)
(3), and the centers of gravity of the first, second and third movable bodies are substantially at the same position (FIG. 1). Since the third movable body (I) is in the inner space of the first movable body (2) and the center of gravity is at the same position,
The movable body (1) does not break the balance of the vibration of the first movable body (2) in the x direction. Similarly, since the second movable body (3) is located in the inner space of the third movable body (I) and the center of gravity is at the same position, the third movable body (I) is moved in the y direction of the second movable body (3). The balance of the motion of each movable body is good without breaking the balance of the vibration, and the efficiency of converting the angular velocity into the vibration in the y direction is good.

(3) Second movable body (3) and third movable body (I)
Is a rectangular ring on the x, y plane, and the second movable body (3)
There is a third movable body (I) in the inner space of the first movable body (I) and a first movable body (2) in the inner space of the third movable body (I), and the centers of gravity of the first, second and third movable bodies are substantially the same. Position (FIG. 4). The mode (FIG. 1) of the above (2) is the first movable body (2) and the third movable body from the position of the center of gravity.
In contrast to the arrangement of (I) and the second movable body (2), in this embodiment (FIG. 3), the second movable body
(3), the third movable body (I) and the first movable body (2) are arranged in this order, and the positions of the first movable body (2) and the second movable body (3) are interchanged. As in the above mode (2), the movement of each movable body is well balanced, and the efficiency of converting the angular velocity into the y-direction vibration is high.

(4) The first movable body (2) is floatingly supported with respect to the substrate (1) by beams (22a-d) extending in the y direction and having one end fixed to the substrate (1). Since the beams (22a to 22d) extending in the y direction do not bend in the y direction but in the x direction, the first movable body
(2) is a floating support that is immovable in the y direction and movable in the x direction with respect to the substrate (1). The floating support of the first movable body (2) and the displacement only in the x direction are reliable.

(5) The second movable body (3) is floatingly supported on the substrate (1) by beams (32a to 32d) fixed at one end to the substrate (1) and extending in the x direction. The beams (32a to 32d) extending in the x direction are x
Since the second movable body (3) bends in the y direction without bending in the direction, the second movable body (3) is a floating support that is immovable in the x direction and movable in the y direction with respect to the substrate (1). The floating support of the second movable body (3) with respect to the substrate (1) and the displacement only in the y direction are reliable.

(6) The third movable body (I) is connected to the first movable body (2) by beams (IX1 to IX4) extending in the x direction and to the beam (Iy1) extending in the y direction.
4) to the second movable body (3). Beam extending in x direction (IX
1 to 4), the third movable body (I) vibrates in the x-direction similarly to the first movable body (2), and furthermore, the first movable body (2)
Can also vibrate in the y direction where it cannot vibrate, and also vibrates in the y direction when an angular velocity about the z axis is applied. This y vibration is y
Propagation to the second movable body (3) by beams (Iy1 to 4) extending in the direction, but vibration in the x direction from the third movable body (I) to the second movable body (3) is caused by the beams (Iy1 to 4). ). Only the y vibration of the third movable body (I) reliably propagates to the second movable body (I).

(7) The first movable body (2), the second movable body (3) and the third movable body (I) have their centers of gravity substantially at the same position, and have an xz plane and a yz plane passing through the centers of gravity. It is substantially symmetric with respect to the plane.

According to this, the power points of the driving force and the Coriolis force applied to each movable body (2, 3, I) substantially pass through the center of gravity, and the generation of the rotational moment due to the difference in the position of the center of gravity between the movable bodies. Is substantially eliminated, so that unnecessary vibration or deviation in the vibration direction is substantially eliminated, and the S / N of the angular velocity detection is improved.

Other objects and features of the present invention will become apparent from the following description of embodiments with reference to the drawings.

[0021]

【Example】

-First Embodiment- FIG. 1 shows a first embodiment of the present invention. In this embodiment, the second
This is an angular velocity sensor that detects an angular velocity about the z-axis applied to the floating body 3 and the third floating body I. FIG.
2B is an enlarged view of one side of the second floating body 3 shown in FIG. 2, and FIG. 2B shows a cross section taken along line 2B-2B on FIG.

Please refer to FIG. 1 and FIG. The silicon substrate 1 on which the insulating layer is formed is made of polysilicon (hereinafter referred to as conductive polysilicon) containing impurities for making it conductive.
Floating body anchors 8a-8f, fixed electrode pad 10,
11 and the electrode pad of the excitation detection electrode are joined,
Wiring (1) formed on an insulating layer on silicon substrate 1
2, 13 etc.), the first floating body 2, the second floating body 3, the third floating body I, of the semiconductor thin film made of conductive polysilicon.
The fixed electrodes 4, 5, 6a to 6c, 7a to 7c are connected to connection electrodes. Note that a silicon substrate 1 having a conductivity (n) opposite to the conductivity type (p) of polysilicon is used, wiring is formed on the silicon substrate 1 by pn junction, and the wiring and floating anchors 8a to 8d and The electrode pads 10 and 11 of the fixed electrode may be joined to the electrode pads of the connection electrodes.

A first set of floating support beams 22a to 22d extending in the y direction are continuous with the floating body anchors 8a to 8d,
A rectangular ring-shaped first floating body 2 substantially parallel to the surface of the substrate 1 is continuous with these support beams 22a to 22d.

A plurality of movable comb electrodes 23a and 23b for x driving protrude from the first floating body 2 to the left and right (x direction) in a comb shape at a constant pitch in the y direction. The base of the fixed electrode 4 is continuous with the electrode pad 10 of one fixed electrode, and the base of the fixed electrode 4 is inserted into the inter-tooth slot of the movable comb-shaped electrode 23a. Tooth electrode 4
2 and the other fixed electrode electrode pad 11 has:
The base of the fixed electrode 5 is continuous, and the base includes a comb-shaped fixed comb-shaped electrode 52 for x-drive, which has entered the interdental slot of the movable comb-shaped electrode 23b. There is a minute gap between the movable comb electrodes 23a and 23b for x driving and the fixed comb electrodes 42 and 52 for x driving.

A third set of floating support beams Ix1 to Ix4 extending in the x direction are continuous with the first floating body 2, and these support beams Ix1 to Ix4 are substantially parallel to the surface of the substrate 1.
The rectangular ring-shaped third floating body I is continuous.

On the third floating body I, a fourth set of floating support beams Iy1 to Iy4 extending in the y direction in the inner space of the rectangular ring are continuous, and these support beams Iy1 to Iy4 are connected to the surface of the substrate 1 Ring-shaped second floating body 3 substantially parallel to
Is continuous.

A second set of floating support beams 32 extending in the x-direction
a to 32d are integrally connected to the base 31 of the second floating body 3, and the other ends of these support beams are connected to the anchor 8
e, 8f and supported by the substrate 1.

On the main body 31 of the second floating body 3, comb-shaped electrodes 33a for detecting y displacement, which extend in the x direction and are parallel to the second set of support beams 32a to 32d, are distributed in the y direction. It extends in the x direction. The comb electrodes 33a are distributed at a predetermined pitch in the y direction. In the gap within one pitch of this distribution, one of the first set of many fixed comb-teeth electrodes 6a for detecting the y-direction displacement and one of the second set of many fixed comb-teeth electrodes 7a for the y-direction displacement detection are provided. There is one. First set of fixed comb-teeth electrodes 6a
Is on the branch line (FIG. 2) of the wiring 13 formed on the insulating layer on the silicon substrate 1 and is electrically at the same potential as the wiring 13. The second set of fixed comb-teeth electrodes 7 a is on a branch line (FIG. 2) of the wiring 12 formed on the insulating layer on the silicon substrate 1, and is electrically at the same potential as the wiring 12.

From one of the x-axis parallel sides (one pair) of the first floating body 2, a movable comb electrode 24a for x-movement detection protrudes in the y-direction. 1
There is a set of comb electrodes 6c and a second set of comb electrodes 7c for x-movement detection, each on a separate line. The movable comb electrode 24a, the first set of comb electrodes 6c and the second
The same thing as the set of comb-tooth electrodes 7c is also on the other side of the x-axis parallel side (one pair) of the first floating body 2.

The first set of floating support beams 22a-22 described above
d, first floating body 2, second set of floating support beams 32a to 32
d, second floating body 3, third and fourth sets of floating support beams I
x1 to Ix4, Iy1 to Iy4, the comb teeth 42, 52 of the fixed electrodes 4, 5, and the comb tooth electrodes 24a for x movement detection.
6c and 7c are separated from the surface of the substrate 1 in the z direction.
That is, it faces the surface of the substrate 1 with a gap. These are formed integrally and continuously on the floating body anchor and the fixed electrode electrode pad after forming the floating body anchor and the fixed electrode pad on the surface of the silicon substrate 1 by the micro-machining technology. As described above, the substrate 1
In this specification, a support mode that can be displaced or bent in the x direction and / or the y direction with respect to the substrate 1 away from the surface of the substrate 1 is referred to as “floating” or “movable”.

The first, second and third floating bodies 2,
The shape of 3, I is a ro-shaped ring, which is vertically and symmetrically with respect to the intersection of each two diagonals, the center of gravity is at the intersection, and the first, second and third floating bodies 2,3,
The center of gravity of I at rest is at the same position. The shapes of the first to third floating bodies 2, 3, I, and the support beams 22a to 22d, 32
The distributions of a to 32d, IX1 to 4, and Iy1 to 4 are substantially symmetric with respect to the xz plane and the yz plane passing through the center of gravity.

Since the first set of floating support beams 22a to 22d supporting the first floating body 2 are floating from the base 1 and extend in the y direction, they do not bend in the y direction, but in the x direction. Easy to bend, the first floating body 2 hardly vibrates in the y direction,
Vibration easily in the x direction. Since the second floating body 3 is supported by the substrate 1 via the second set of floating support beams 32a to 32d extending in the x direction, the second floating body 3 hardly vibrates in the x direction and easily vibrates in the y direction. Since the third floating body I is continuous with the first floating body 2 via the third set of floating support beams Ix1 to Ix4 extending in the x direction, the vibration of the first floating body 2 in the x direction also causes the third floating body I to move in the x direction. And can also vibrate in the y-direction, so that when an angular velocity about the z-axis is applied, it also vibrates in the y-direction. This third
A fourth body of floating support beams Iy1 extending in the y direction is provided on the floating body I.
Since the second floating body 3 is continuous via .about.Iy4, when the third floating body I vibrates in the y direction, the second floating body 3 also vibrates in the y direction.

That is, the first floating body 2 can vibrate in the x direction but cannot vibrate in the y direction. The second floating body 3 is y
It can vibrate in the direction but not in the x direction. The third floating body I can vibrate in the y direction with respect to the first floating body 2 but cannot vibrate in the x direction, and can vibrate in the x direction with respect to the second floating body 3. It cannot vibrate in the y direction. Thereby, when the angular velocity around the z-axis is not applied,
When the first floating body 2 is driven to vibrate in the x direction, the first floating body 2
And the third floating body I oscillates in the x direction.
Does not vibrate in the direction. The second floating body 3 is stationary. When an angular velocity about the z-axis is applied, the third floating body I vibrates in the y direction in addition to the x direction, and the second floating body 3 vibrates in the y direction in the same manner as the vibration in the y direction.

The first floating body 2 (and the second floating body 3 and the third floating body 3)
The floating body I) is connected to the x drive circuit 15 via the wirings 9a and 9b on the substrate 1, where it is connected to the equipment ground (GND). The fixed electrodes 4 and 5 are
11 is connected to the x drive circuit 15 via an electrode conductor. The x drive circuit 15 alternately applies a high voltage to the fixed electrodes 4 and 5 and repeats this. The first floating body 2 (and the third floating body I) are pulled rightward in FIG. 1 when a high voltage is applied to the fixed electrode 4 (comb electrode 42), and the fixed electrode 5 (comb electrode 52). ) Is pulled to the left when high voltage is applied to
Vibrates left and right.

When the first floating body 2 moves to the right,
Although the capacitance between the movable comb electrode 24a for x-movement detection and the first set of fixed comb-teeth electrodes 6c for x-movement detection decreases, the movable comb-teeth electrode 24a and the second comb-electrode for x-movement detection are reduced. The capacitance between the pair of fixed comb electrodes 7c increases. The opposite is true when moving to the left. The movable comb electrode 24a is at the equipment earth potential (GND), but is fixed to the fixed comb electrodes 6c and 7c.
c is connected to the capacitance detection circuit 16. The capacitance detection circuit 16 generates an electric signal indicating the difference between the capacitance of the electrodes 6c and 7c with respect to the electrode 24a (the equipment ground potential GND), and supplies the signal to the x drive circuit 15. This electric signal is an AC signal (hereinafter referred to as an x vibration synchronization signal) indicating a level change synchronized with the x vibration of the first floating body 2. Each time the absolute value of the level of the AC signal reaches the set value, the x drive circuit 15 switches the electrodes 4 and 5 to which the high voltage is applied. Thereby, the first floating body 2 (and the third floating body I) vibrate in the x direction at a predetermined amplitude.

As a driving method, a capacitance detecting circuit 1
6 is driven at a resonance frequency by PLL (Phase Lock Loop) control using the signal obtained from the control circuit 6, the drive amplitude is obtained from the signal obtained from the capacitance detection circuit 16, and the drive voltage is increased or decreased to increase or decrease the amplitude. May be controlled to be constant. This enables low-voltage driving.

The movable comb electrode 24a and the fixed comb electrodes 6c, 7c may have the same shape as the drive comb electrodes 23, 42, 52 and may be arranged in the same direction as the drive comb electrodes. Thereby, the drive amplitude can be set large.

When the second floating body 3 vibrates in the y direction, the second floating body 3
The capacitance between the comb electrode 33a of the floating body 3 and the fixed comb electrodes 6a and 6b fluctuates, and the capacitance between the comb electrode 33a and the fixed comb electrodes 7a and 7b is opposite to this. The capacitance fluctuates. The capacitance detection circuit 17 includes a comb-shaped electrode 33a.
Electric signal (y vibration synchronization signal) representing the difference between the capacitance between the fixed comb-tooth electrodes 6a and 6b and the capacitance between the comb-tooth electrode 33a and the fixed comb-tooth electrodes 7a and 7b. Is generated and supplied to the signal processing circuit 18. If the x vibration of the second floating body 3 is constant, there is a certain relationship between the angular velocity and the amplitude of the y vibration of the second floating body 3 and the third floating body I. The signal processing circuit 18 converts the y vibration synchronization signal into a signal representing angular velocity (angular velocity signal) based on this relationship.

FIG. 3 shows that the x driving circuit 15 has fixed electrodes 4 and 5.
Between the voltages V1 and V2 applied to the first floating body 2 and the x vibration (displacement in the x direction) of the first floating body 2 (and the third floating body I), and
The relationship between the x vibration and the y vibration (displacement in the y direction) of the third floating body I and the second floating body 3 is shown. Depending on the direction of the angular velocity (clockwise / counterclockwise), the phase of the y vibration is shifted by 180 degrees (the solid line of y displacement and the two-dot chain line in FIG. 3). The signal processing circuit 18 determines the direction (clockwise / counterclockwise) of the angular velocity based on the phase difference of the y vibration synchronization signal with respect to the x movement synchronization signal from the capacitance detection circuit 16 and outputs a direction signal indicating the direction. , An angular velocity value signal representing the absolute value of the angular velocity corresponding to the amplitude of the y vibration synchronization signal.

According to the first embodiment described above, the first floating body 2
The movable comb electrodes 23a and 23b and the fixed comb electrodes 42,
52, the electrostatic attraction force in the + y direction or the −y direction is likely to be applied, that is, the y driving force is likely to act, but the first floating body 2 is provided by the first set of floating support beams 22a to 22d extending in the y direction. Are supported, the y movement of the first floating body 2 is prevented by the first set of support beams 22a to 22d, and the first floating body 2 is not y-driven by the x drive voltages V1 and V2. Thereby, the efficiency of the x vibration drive of the first floating body 2 (and the third floating body I) is improved, and the x vibration is stabilized.

On the other hand, since the third floating body I is supported by the first floating body 2 by the third set of floating support beams Ix1 to Ix4 extending in the x direction, it easily vibrates in the y direction when an angular velocity is applied. . This y vibration includes y by x driving voltages V1 and V2.
Since the displacement is substantially not included, and the x vibration is stable as described above, the y vibration of the third floating body I corresponds only to the angular velocity. 4th
Since the second floating body 3 is connected via the pair of floating support beams Iy1 to Iy4, and the second floating body 3 is supported on the substrate 1 by the second set of floating support beams 32a to 32d extending in the x direction. The second floating body I in synchronization with only the y-direction vibration of the third floating body I.
The floating body 3 vibrates in the y direction and does not vibrate in the x direction. Further, when acceleration in the z direction is applied, the third floating body I is supported by the first and second floating bodies via the beam, and thus is easily displaced in the z direction, but the second floating body 3 has one end. Is floatingly supported by the beams 32a to 32d supported by the anchors 8e and 8f of the substrate 1, so that the substrate 1 can be displaced in the z direction, but the resistance to the displacement is large, and the third floating body I is more displaceable in the z direction. Is not easily displaced. Thereby, the displacement of the second floating body 3 with respect to the fixed electrodes 42 and 52 due to the acceleration in the z direction is small,
The S / N of the angular velocity detection signal is high. In addition, the stability of detection accuracy is high.

Further, the centers of gravity of the first to third floating bodies 2, 3, I are substantially at the same position when they are at rest, and the shapes of these floating bodies and the distribution of the supporting beams continuous therewith are different. Are substantially symmetrical with respect to the xz plane and the yz plane passing through the center of gravity, the power points of the driving force and Coriolis force applied to each of the floating bodies 2, 3, I substantially pass through the center of gravity, and the center of gravity between the floating bodies Rotational moments due to different positions or asymmetrical distribution of the support beams are substantially eliminated, so that unnecessary vibrations or deviations in the vibration direction are substantially eliminated, and the S / N of the angular velocity detection is improved.

Second Embodiment FIG. 4 shows a second embodiment of the present invention. In the second embodiment, the positions of the second floating body 3 and the first floating body 1 are exchanged, and the third floating body I is placed inside the second floating body 3 and the first floating body I is placed inside the third floating body I. The floating body 2 was arranged. Accordingly, fixed electrodes 4 and 5 for exciting the first floating body 2 in the x direction and electrodes 6c and 7c for vibration detection are formed inside the third floating body I, and an electrode for y vibration detection is formed. The second group consists of two groups.
Formed outside the floating body 3.

The branch lines (dotted lines) continuous to the electrode leads 13a and 13b for the fixed electrode of the electrode group for detecting the y-vibration are covered with an insulating layer, and the fixed electrode is partially removed from the fixed electrode. 6a and 6b are joined. That is, the fixed electrodes 6a and 6b are electrically at the same potential as the electrode leads 13a and 13b, respectively. An electrode lead 12 is formed on the insulating layer.
A continuous branch line is joined to a and 12b, and fixed electrodes 7a and 7b are joined to this branch line. That is, the fixed electrodes 6a and 6b are electrically at the same potential as the electrode leads 13a and 13b, respectively.

The capacitance detecting circuit 17 includes a fixed electrode 6a,
6b and the capacitance between the movable electrodes 33a and 33b of the second floating body 3, and the level corresponding to the difference between the capacitance between the fixed electrodes 7a and 7b and the movable electrodes 33a and 33b of the second floating body 3. A capacitance detection signal is generated and provided to the signal processing circuit 18. This capacitance detection signal indicates a level fluctuation synchronized with the y vibration of the second floating body 3.

Other configurations and functions of the second embodiment are as follows.
As in the first embodiment, the displacement of the second floating body 3 with respect to the fixed electrodes 42 and 52 due to the acceleration in the z direction is small, and the S / N of the angular velocity detection signal is high. In addition, the stability of detection accuracy is high.

[Brief description of the drawings]

FIG. 1 is a plan view of a first embodiment of the present invention.

FIG. 2A shows a part 2 of a second floating body 3 shown in FIG.
2A is an enlarged plan view, and FIG. 2B is a sectional view taken along line 2B-2B in FIG.

3 shows the waveform of the output voltage of the x drive circuit 15 shown in FIG. 1, the x displacement of the first floating body 2, and the third and second floating bodies I,
3 is a time chart showing a y displacement of 3.

FIG. 5 is a plan view of a second embodiment of the present invention.

[Explanation of symbols]

1: Silicon substrate 2: First floating body 21: B-shaped base 22a-d: First set of floating support beams 23a, 23b: Movable comb electrode 24a, 24
b: movable side comb-tooth electrode 25a, 25b: floating connecting beam 3: second floating body 31: backbone 32a-d: second set of floating support beams 33a, 33b: comb-tooth electrode I: third floating body Ix1-Ix4 : Third set of floating support beams Iy1 to Iy
4: Fourth set of floating support beams 4: Fixed electrode 41: Electrode base 42: Fixed comb electrode 5: Fixed electrode 51: Electrode base 52: Fixed comb electrode 6a to 6c: Fixed electrode 7a to 7c: Fixed comb tooth Electrodes 8a-f: Floating body anchors 9a, 9b: Wiring 10, 11: Electrode pads for fixed electrodes 12, 12a, b, 13, 13
a, 13b: wiring 15: x drive circuit 16, 17: capacitance detection circuit 18: signal processing circuit

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[Procedure amendment]

[Submission date] November 7, 1997

[Procedure amendment 1]

[Document name to be amended] Statement

[Correction target item name] Brief description of drawings

[Correction method] Change

[Correction contents]

[Brief description of the drawings]

FIG. 1 is a plan view of a first embodiment of the present invention.

FIG. 2A shows a part 2 of a second floating body 3 shown in FIG.
2A is an enlarged plan view, and FIG. 2B is a sectional view taken along line 2B-2B in FIG.

3 shows the waveform of the output voltage of the x drive circuit 15 shown in FIG. 1, the x displacement of the first floating body 2, and the third and second floating bodies I,
3 is a time chart showing a y displacement of 3.

FIG. 4 is a plan view of a second embodiment of the present invention.

[Description of Signs] 1: Silicon substrate 2: First floating body 21: B-shaped base 22a-d: First set of floating support beams 23a, 23b: Movable comb electrode 24a, 24
b: movable side comb-tooth electrode 25a, 25b: floating connecting beam 3: second floating body 31: backbone 32a-d: second set of floating support beams 33a, 33b: comb-tooth electrode I: third floating body Ix1-Ix4 : Third set of floating support beams Iy1 to Iy
4: Fourth set of floating support beams 4: Fixed electrode 41: Electrode base 42: Fixed comb electrode 5: Fixed electrode 51: Electrode base 52: Fixed comb electrode 6a to 6c: Fixed electrode 7a to 7c: Fixed comb tooth Electrodes 8a-f: Floating body anchors 9a, 9b: Wiring 10, 11: Electrode pads for fixed electrodes 12, 12a, b, 13, 13
a, 13b: wiring 15: x drive circuit 16, 17: capacitance detection circuit 18: signal processing circuit

Claims (7)

[Claims] A first movable body supported by the substrate so as to be movable in the x direction and substantially immovable in the y direction;
A second movable body supported to be movable in the direction and substantially immovable in the x direction; movable in the x and y directions, movable in the y direction with respect to the first movable body, and substantially in the x direction. A third movable body, which is movably connected in the x direction to the second movable body and is substantially movably connected in the y direction with respect to the second movable body; an excitation means for oscillating the first movable body in the x direction; An angular velocity sensor comprising: displacement detection means for detecting a y-direction displacement of the second movable body; and conversion means for converting a displacement signal generated by the displacement detection means into an angular velocity signal. 2. The first movable body and the third movable body have a rectangular ring shape on the x, y plane, and the third movable body is provided in the inner space of the first movable body and the third movable body is provided in the inner space of the third movable body. The angular velocity sensor according to claim 1, wherein there are two movable bodies, and the centers of gravity of the first, second, and third movable bodies are substantially at the same position. 3. The second movable body and the third movable body have a rectangular ring shape on the x, y plane, and the third movable body is provided in the inner space of the second movable body and the third movable body is provided in the inner space of the third movable body. The angular velocity sensor according to claim 1, wherein there is one movable body, and the centers of gravity of the first, second, and third movable bodies are substantially at the same position. 4. The first movable body has one end fixed to a substrate.
4. The angular velocity sensor according to claim 1, wherein the angular velocity sensor is floatingly supported on the substrate by a beam extending in the direction. 5. The second movable body has an end fixed to the substrate.
5. The angular velocity sensor according to claim 1, wherein the angular velocity sensor is floatingly supported on the substrate by a beam extending in the direction. 6. The third movable body is connected to the first movable body by a beam extending in the x direction and to the second movable body by a beam extending in the y direction.
Claim 1, Claim 2, Claim 3, Claim 4, or Claim 5
An angular velocity sensor as described. 7. The first movable body, the second movable body, and the third movable body have substantially the same center of gravity, and have a substantially symmetric structure with respect to an xz plane and a yz plane passing through the center of gravity. ,
The angular velocity sensor according to claim 1.