JP3767212B2 - Vibration gyro support structure and support method - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a vibration gyro support structure and a support method, and more particularly to a vibration gyro support structure and a support method for supporting a vibration gyro used for camera shake prevention, a car navigation system, and the like.
[0002]
[Prior art]
FIG. 8 is a perspective view showing a vibration gyro using a conventional support structure, and FIG. 9 is a sectional view thereof. The vibration gyro 1 includes a vibrator 2. The vibrator 2 is formed by joining two piezoelectric substrates 3a and 3b. These piezoelectric substrates 3a and 3b are polarized in opposite thickness directions as indicated by arrows in FIG.
[0003]
Divided electrodes 4a and 4b are formed on the outer surface of one piezoelectric substrate 3a. These electrodes 4a and 4b are divided into two in the width direction of the side surface of the piezoelectric substrate 3a and are formed to extend in the longitudinal direction of the piezoelectric substrate 3a. Furthermore, another electrode 5 is formed on the entire outer surface of the other piezoelectric substrate 3b. The vibrator 2 is supported by the support member 6 on the surface on which the electrode 5 is formed. The support member 6 is formed of, for example, a metal wire. The support member 6 is bent to form a protrusion 6a. The protrusion 6 a is brought into contact with the electrode 5 at a portion corresponding to the two node points of the vibrator 2. Then, the support member 6 is fixed to the electrode 5 of the vibrator 2 by the elastic adhesive 7 containing silicon resin.
[0004]
In the vibrating gyroscope 1, a drive signal is applied between the electrodes 4 a and 4 b and the electrode 5. Since the two piezoelectric substrates 3a and 3b are polarized in directions opposite to each other, the vibrator 2 has a bimorph structure, and the vibrator 2 forms the electrodes 4a and 4b and the electrodes 5 by the drive signal. Flexurally vibrates in a direction perpendicular to the surface. At this time, the vibrator 2 bends and vibrates around two node points slightly inside from both ends in the longitudinal direction. When the vibrator 2 is bending-vibrated in such a direction, the same signal is output from the electrodes 4a and 4b. Therefore, if the difference between these signals is taken, the two output signals are canceled and become zero. .
[0005]
When the vibrator 2 is bent and vibrated, when the vibrator 2 rotates about the axis of the vibrator 2, a Coriolis force acts in a direction orthogonal to the direction of the bending vibration of the vibrator 2. Therefore, the direction of the bending vibration of the vibrator 2 changes, and the output signals of the electrodes 4a and 4b change. That is, when the output signal from one electrode 4a increases corresponding to the Coriolis force, the output signal from the other electrode 4b decreases corresponding to the Coriolis force. Therefore, if the difference between the output signals from these electrodes 4a and 4b is taken, only a signal corresponding to the Coriolis force can be obtained. Thus, the rotational angular velocity applied to the vibrating gyroscope 1 can be detected by measuring the difference between the output signals of the electrodes 4a and 4b.
[0006]
[Problems to be solved by the invention]
However, in such a vibration gyro support structure, the protrusion of the support member is brought into contact with the side surface of the vibrator and fixed with an elastic adhesive, so that the vibrator easily tilts with respect to the support member. It is difficult to keep the distance from the support member constant. Therefore, the vibration of the vibrator is damped by the support member, which causes a temperature drift. Further, vibration leakage of the vibrator occurs through the support member, which also causes a temperature drift.
[0007]
Therefore, a main object of the present invention is to provide a support structure for a vibrating gyroscope capable of reducing temperature drift.
Another object of the present invention is to provide a support method for obtaining a support structure for a vibrating gyroscope capable of reducing temperature drift.
[0008]
[Means for Solving the Problems]
The present invention relates to a vibration gyro support structure for detecting a rotational angular velocity using flexural vibration of a vibrator having electrodes formed on side surfaces, and a support member extending in the width direction of the vibrator to support the vibrator In the portion corresponding to the node point of the bending vibration of the vibrator, the electrode on the side surface of the vibrator and the support member are spaced apart by a support portion made of a hardened conductive adhesive , A support structure for a vibration gyro, wherein a support member is fixed to a support member made of a conductive adhesive cured on an electrode with a conductive adhesive .
In such a vibration gyro support structure, the support member is fixed to the electrode formed on one side surface of the vibrator or the electrode formed on the opposite side surface through a support portion made of a hardened conductive adhesive. Can do.
Moreover, it is preferable that the hardness of the hardened | cured conductive adhesive is pencil hardness B-6H.
Furthermore, the present invention is conducting the process of printing a conductive adhesive to the electrodes formed on the side surface of the vibrator in a portion corresponding to a node point of a vibrator of the flexural vibration, the surface constituted by the electrode and fixed interval Forming a support part by forming it on a conductive adhesive, placing a support member on a surface formed on the support part, and fixing the support member to the support part with a conductive adhesive. This is a method for supporting a vibrating gyroscope.
[0009]
Since the electrode formed on the side surface of the vibrator and the support member are arranged at a predetermined interval, the vibration of the vibrator is difficult to be damped and temperature drift can be suppressed. Further, since the support member is fixed to the vibrator via the conductive adhesive and is not in direct contact with the vibrator, vibration leakage from the support member can be suppressed. Furthermore, the effect of suppressing temperature drift is high by keeping the hardness of the conductive adhesive in the range of B to 6H in pencil hardness.
In order to obtain such a supporting structure for a vibrating gyroscope, first, a conductive adhesive is printed on the side surface of the vibrator, and the conductive adhesive is processed so that a certain distance is formed from the electrode on the side face of the vibrator. A support having a surface is formed. This surface can be accurately formed using a dicer or the like. Therefore, by arranging a support member on the surface of the support portion and fixing with a conductive adhesive, the position accuracy of the support member is improved, and the support member can be fixed at a constant interval from the electrode, It can be supported at a position close to the node point of the vibrator.
[0010]
The above object, other objects, features and advantages of the present invention will become more apparent from the following detailed description of embodiments with reference to the drawings.
[0011]
DETAILED DESCRIPTION OF THE INVENTION
FIG. 1 is a perspective view showing an example of a vibrating gyroscope using the support structure of the present invention, and FIG. 2 is a sectional view thereof. The vibrating gyroscope 10 includes a vibrator 12. The vibrator 12 includes a rectangular parallelepiped first piezoelectric substrate 14a and a second piezoelectric substrate 14b. As these piezoelectric substrates 14a and 14b, for example, piezoelectric ceramics or single crystals of LiNbO ₃ or LiTaO ₃ are used. Then, the first piezoelectric substrate 14a and the second piezoelectric substrate 14b are joined. The first piezoelectric substrate 14a and the second piezoelectric substrate 14b are polarized in opposite thickness directions as indicated by arrows in FIG. Therefore, the vibrator 12 has a bimorph structure.
[0012]
Two electrodes 16 and 18 are formed on the outer surface of the first piezoelectric substrate 14a. These electrodes 16 and 18 are divided into two in the width direction of the first piezoelectric substrate 14a, and are formed to extend in the longitudinal direction of the first piezoelectric substrate 14a. Further, another electrode 20 is formed on the entire outer surface of the second piezoelectric substrate 14b. In order to manufacture such a vibrator 12, for example, two large piezoelectric substrates are joined with an epoxy resin or the like to form a multilayer substrate, electrodes are formed on both surfaces of the multilayer substrate, and one piezoelectric substrate is formed. After forming grooves at predetermined intervals in the electrode formed thereon, the laminated substrate may be cut by dicing cut or the like.
[0013]
Linear support members 22a and 22b formed of, for example, metal wires are attached to the electrode 20 forming surface. The support members 22 a and 22 b are bonded to the electrode 20 with the conductive adhesive 24 so as to extend in the width direction of the vibrator 12 at portions corresponding to the two node points of the vibrator 12. At this time, the support members 22a and 22b are attached so that the distance between the vibrator 12 and the support members 22a and 22b is constant.
[0014]
In order to produce the vibrating gyroscope 10, a conductive adhesive is printed on the electrode 20 at a portion corresponding to the two node points of the vibrator 12. After the conductive adhesive is cured, as shown in FIG. 3, a groove 26a including a surface parallel to the electrode 20 is formed in the cured conductive adhesive using a dicer or the like, and the support portion 26 is formed. The As described above, in the support portion 26, the groove 26 a is parallel to the electrode 20, that is, parallel to the outer surface of the vibrator 12, so that the distance between the groove 26 a and the vibrator 12 is constant. As shown in FIG. 4, the support member 22a (22b) is disposed in the groove 26a of the support portion 26, and the support member 22a (22b) and the support portion 26 are fixed to each other with a conductive adhesive.
[0015]
In order to use the vibrating gyroscope 10, resistors 30, 32 are connected to the electrodes 16, 18 formed on the first piezoelectric substrate 14a, as shown in FIG. An oscillation circuit 34 is connected between the resistors 30 and 32 and the electrode 20. The oscillation circuit 34 includes, for example, an amplifier circuit and a phase correction circuit, and a signal output from the electrode 20 is fed back to the oscillation circuit 34. Then, the level and phase of the fed back signal are adjusted by the amplifier circuit and the phase correction circuit, and applied to the electrodes 16 and 18.
[0016]
The electrodes 16 and 18 are connected to the input terminal of the differential circuit 36. The output terminal of the differential circuit 36 is connected to the synchronous detection circuit 38. In the synchronous detection circuit 38, for example, the output signal of the differential circuit 36 is detected in synchronization with the signal of the oscillation circuit 34. The synchronous detection circuit 38 is connected to the smoothing circuit 40, and the smoothing circuit 40 is further connected to the DC amplification circuit 42.
[0017]
The vibration gyro 10 is driven by self-excitation by the oscillation circuit 34. At this time, since the vibrator 12 has a bimorph structure, when the first piezoelectric substrate 14a extends in a direction parallel to the main surface, the second piezoelectric substrate 14b contracts in a direction parallel to the main surface. . Conversely, when the first piezoelectric substrate 14a contracts in a direction parallel to the main surface, the second piezoelectric substrate 14b extends in a direction parallel to the main surface. Therefore, the vibrator 12 bends and vibrates in a direction orthogonal to the electrodes 16 and 18 formation surface and the electrode 20 formation surface.
[0018]
When no rotational angular velocity is applied to the vibrating gyroscope 10, the vibrating state of the electrodes 16 and 18 forming part Ru Oh same. Therefore, the signals output from the electrodes 16 and 18 are the same and are canceled by the differential circuit 36, so that no signal is output from the differential circuit 36. When rotated about the axis of the vibrator 12, a Coriolis force acts in a direction orthogonal to the direction of the bending vibration. Due to this Coriolis force, the direction of bending vibration of the vibrator 12 changes. For this reason, a difference occurs in the vibration state of the portions where the electrodes 16 and 18 are formed, and a difference occurs in the signals output from the electrodes 16 and 18. For example, when the signal output from the electrode 16 increases, the signal output from the electrode 18 decreases. Conversely, when the signal output from the electrode 16 decreases, the signal output from the electrode 18 increases. Therefore, the difference between the output signals of the two electrodes 16 and 18 is obtained from the differential circuit 36. Changes in the output signals of the electrodes 16 and 18 correspond to changes in the direction of bending vibration of the vibrator 12, that is, Coriolis force. Therefore, the differential circuit 36 outputs a signal having a level corresponding to the Coriolis force.
[0019]
The output signal of the differential circuit 36 is detected by the synchronous detection circuit 38 in synchronization with the signal of the oscillation circuit 34. At this time, only a positive part, only a negative part, or a signal obtained by inverting either positive or negative of the output signal of the differential circuit 36 is detected. The signal detected by the synchronous detection circuit 38 is smoothed by the smoothing circuit 40 and further amplified by the DC amplification circuit 42. Therefore, the rotational angular velocity applied to the vibrating gyroscope 10 can be detected by measuring the output signal of the DC amplification circuit 42.
[0020]
When the direction of the rotational angular velocity is reversed, the change in the direction of bending vibration of the vibrator 12 is also reversed, and the change in the output signals of the electrodes 16 and 18 is reversed. Therefore, the signal output from the differential circuit 36 has an opposite phase, and the signal detected by the synchronous detection circuit 38 has an opposite polarity. Therefore, the polarity of the output signal from the DC amplifier circuit 42 is also reversed. Therefore, the direction of the rotational angular velocity can be detected from the polarity of the output signal of the DC amplifier circuit 42.
[0021]
In the vibrating gyroscope 10, support members 22a and 22b are attached to the vibrator 12 by a support portion 26 formed of a conductive adhesive 24, and the distance between the vibrator 12 and the support members 22a and 22b is kept constant. Therefore, the bending vibration of the vibrator 12 is not easily damped by the support members 22a and 22b. Therefore, the temperature drift of the vibrating gyroscope 10 can be reduced. In particular, it has been found that this effect is high when the hardness of the conductive adhesive 24 is in the range of pencil hardness B to 6H. As an experimental example, the relationship between the hardness and drift of the conductive adhesive 24 was examined, and the result is shown in FIG. As can be seen from FIG. 6, it can be seen that the hardness of the conductive adhesive 24 is as small as 20 (deg / sec) between the pencil hardness B to 6H.
[0022]
Further, since the support members 22a and 22b are attached to the vibrator 12 via the support portion 26 formed of the conductive adhesive 24, and the support members 22a and 22b are not in direct contact with the vibrator 12, the vibrator 12 Is less likely to leak from the support members 22a and 22b. Therefore, the temperature drift of the vibrating gyroscope 10 can be reduced.
[0023]
The support member may be attached not only to one side surface of the vibrator 12 but also to opposite side surfaces. In this case, as shown in FIG. 7, four support members 22a, 22b, 22c, and 22d are attached. Here, when the adjacent electrodes 16 and 18 are short-circuited by the support members 22c and 22d, the function as a vibrating gyroscope cannot be performed. Therefore, each of the electrodes 16 and 18 is divided at a position corresponding to the node point of the vibrator 12. The support members 22c and 22d are attached to the electrode portions 16a and 18a formed at the portions corresponding to the node points. In this case, a support portion may be formed on the electrode portions 16a and 18a with a conductive adhesive, a surface parallel to the electrodes 16 and 18 may be formed on the support portion, and the support members 22c and 22d may be attached to the surfaces. Then, an extension portion extending from the support member 22c is connected to the electrode portion 16b at the center portion of the electrode 16, and an extension portion extending from the support member 22d is connected to the electrode portion 18b at the center portion of the electrode 18. Signals can be input and output to the electrodes 16 and 18 via 22c and 22d. Note that the connection structure of the support members 22c and 22d shown in FIG. 7 is an example. If the support members 22c and 22d are connected to the electrodes 16 and 18 and the electrodes 16 and 18 are not short-circuited, other connections are possible. A structure may be adopted.
[0024]
Note that at least one supporting member may be attached to each of the portions corresponding to the two node points of the vibrator 12, and the supporting members 22 a and 22 b are formed in the two portions on the electrode 20 side of the vibrator 12. Then, either one of the support members 22c or 22d may be formed on one portion on the electrode 16 or 18 side. Further, a support member 22a is formed on a portion corresponding to one node point on the electrode 20 side of the vibrator 12, and a support member 22d is formed on a portion corresponding to the other node point on the electrodes 16 and 18 side. Also good. Of course, it goes without saying that the support members 22b and 22c may be formed on the opposite side surfaces of the vibrator 12.
[0025]
By forming the support member from a conductive material such as a metal wire, the support member can be used for signal input / output without using a lead wire. In particular, when attaching support members to all the electrodes 16, 18, and 20, it is not necessary to use lead wires at all, and the influence of the lead wire tension and the like can be eliminated. Therefore, it is possible to obtain the vibrating gyroscope 10 having good characteristics that is not affected by the lead wire and has a small temperature drift.
[0026]
【The invention's effect】
According to the present invention, since the vibrator and the support member extending in the width direction are arranged at a constant interval, the vibration of the vibrator is not easily damped by the support member. Further, since the support member is not in direct contact with the vibrator, the vibration of the vibrator is difficult to leak through the support member. For these reasons, the temperature drift of the vibrating gyroscope can be reduced. In particular, this effect can be increased by setting the hardness of the conductive adhesive within the range of pencil hardness B to 6H.
In addition, a support member having a surface parallel to the electrode formed on the side surface of the vibrator in advance is formed at a position corresponding to the node point of the vibrator, and the support member is disposed on this surface, thereby supporting the support member. The position accuracy can be improved. Accordingly, the distance between the support member and the electrode can be made constant, and the vibrator can be supported at a portion close to the node point of the vibrator, and the temperature drift of the vibration gyro can be reduced.
[Brief description of the drawings]
FIG. 1 is a perspective view showing an example of a vibrating gyroscope using a support structure of the present invention.
2 is a cross-sectional view of the vibrating gyroscope shown in FIG.
3 is a perspective view showing a state in which a support portion is formed on a vibrator in order to produce the vibration gyro shown in FIG. 1; FIG.
4 is an illustrative view showing a state in which a support member is arranged on the support portion shown in FIG. 3; FIG.
FIG. 5 is a block diagram showing a circuit for using the vibration gyro shown in FIG. 1;
FIG. 6 is a graph showing the relationship between the hardness and drift of a conductive adhesive for fixing a support member.
FIG. 7 is a perspective view showing another example of the vibrating gyro support structure according to the present invention.
FIG. 8 is a perspective view showing an example of a vibrating gyroscope using a conventional support structure.
9 is a cross-sectional view of the vibrating gyroscope shown in FIG.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 10 Vibrating gyroscope 12 Vibrator 14a 1st piezoelectric substrate 14b 2nd piezoelectric substrate 16 Electrode 18 Electrode 20 Electrode 22a-22d Support member 24 Conductive adhesive 26 Support part 26a Groove

Claims (4)

A vibration gyro support structure for detecting a rotational angular velocity using flexural vibration of a vibrator having electrodes formed on side surfaces,
A support member extending in the width direction of the vibrator to support the vibrator;
In the portion corresponding to the node point of the bending vibration of the vibrator, the electrode on the side surface of the vibrator and the support member are spaced apart by a support portion made of a hardened conductive adhesive , A support structure for a vibration gyro, wherein the support member is fixed to the electrode with a conductive adhesive through a support portion made of the cured conductive adhesive . 2. The support member according to claim 1, wherein the support member is fixed to the electrode formed on one side surface of the vibrator or the electrode formed on the opposite side surface through a support portion made of the hardened conductive adhesive. The support structure of the vibration gyro described above. The vibration gyro support structure according to claim 1 or 2, wherein the hardened conductive adhesive has a hardness of pencil hardness B to 6H. A step of printing a conductive adhesive on an electrode formed on a side surface of the vibrator in a portion corresponding to a node point of the vibrator that undergoes bending vibration;
A step of forming a support portion by forming a surface at a certain distance from the electrode on the conductive adhesive;
A method for supporting a vibrating gyroscope, comprising: arranging a support member on the surface formed on the support portion; and fixing the support member to the support portion with a conductive adhesive.

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