Oscillation gyro

Description: TECHNICAL FIELD [Detailed description of the invention]

【0001】

[Technical field to which the invention belongs]

The present invention relates to a vibrating gyro, and more particularly to a vibrating gyro used for detecting an angular velocity for preventing camera shake.

【0002】

[Conventional technology]

FIG. 14 is a perspective view showing an example of a conventional vibrating gyro. The vibrating gyro 1 includes, for example, a vibrating body 2 on a regular triangular prism. Piezoelectric elements 3a, 3b, and 3c are formed on the three side surfaces of the vibrating body 2, respectively. In order to use this vibration gyro 1, for example, as shown in FIG. 15, an oscillation circuit 4 is connected between the piezoelectric elements 3a and 3b and the piezoelectric element 3c. Further, the piezoelectric elements 3a and 3b are connected to the detection circuit 5. The detection circuit 5 includes a differential circuit, a synchronous detection circuit, a smoothing circuit, a DC amplifier circuit, and the like.

【0003】

In this vibration gyro 1, the output signal of the piezoelectric element 3c is fed back to the oscillation circuit 4. In the oscillation circuit 4, the feedback signal is amplified, and the phase is further adjusted to form an excitation signal. The excitation signal thus obtained is given to the piezoelectric elements 3a and 3b. As a result, the vibrating body 2 bends and vibrates in a direction orthogonal to the piezoelectric element 3c forming surface. In this state, the bending states of the piezoelectric elements 3a and 3b are the same, and the output signals thereof are also the same. Therefore, no signal is output from the differential circuit of the detection circuit 5. When the vibrating body 2 is flexing and vibrating and is rotated about the axis of the vibrating body 2, the vibration direction of the vibrating body 2 is changed by the Coriolis force. Therefore, there is a difference in the signals output from the piezoelectric elements 3a and 3b, and the signal is output from the differential circuit. This signal is detected by the synchronous detection circuit, smoothed by the smoothing circuit, and amplified by the DC amplifier circuit. Therefore, the rotational angular velocity can be detected by measuring the output signal of the detection circuit 5.

【0004】

Further, as the vibrating gyro 1, as shown in FIG. 16, the vibrating body 2 may be manufactured by joining two piezoelectric body substrates 6a and 6b. These piezoelectric substrates 6a and 6b are polarized in opposite directions as shown by the arrows in FIG. In this case, two electrodes 7a and 7b extending in the longitudinal direction are formed on one surface side of the vibrating body 2, and the electrodes 8 are formed on the entire surface of the other surface side of the vibrating body 2. Even in such a vibrating gyro 1, the angular velocity can be detected by the circuit shown in FIG.

【0005】

[Problems to be Solved by the Invention]

However, with these vibrating gyros, only the angular velocity around the axis of the vibrating body can be detected, and only the angular velocity with respect to one direction can be detected. Therefore, if you want to detect the angular velocity in two directions, you need to use two vibrating gyros, and you need two oscillation circuits to excite these vibrating gyros. Such an oscillator circuit is expensive, and the cost for detecting angular velocities in a plurality of directions is high.

【0006】

Therefore, a main object of the present invention is to provide a vibrating gyro capable of detecting angular velocities in two directions with one element.

【0007】

[Means for solving problems]

In the present invention, the central member, four vibrating arms formed radially outward from the central member so that adjacent objects on the same plane are orthogonal to each other, and the vibrating arm are formed from the central portion. It includes four weight arms formed radially toward the outside, and an excitation detecting means for bending and vibrating the vibration arm on the same plane and outputting a signal generated by the vibration of the vibration arm. It is a vibrating gyro. In such a vibration gyro, the vibration detecting means can be formed by forming the vibration arm and the weight arm with the piezoelectric substrate and forming the electrode on the vibration arm. Further, the central member, the vibration arm and the weight arm may be integrally formed of a metal plate, and the excitation detecting means may be formed by a piezoelectric element formed on the metal plate. Further, the central member may be formed of a piezoelectric body, and the central portion, the vibration arm and the weight arm may be integrally formed. Further, when the vibration arm and the weight arm are formed of the piezoelectric substrate, the vibration arm and the weight arm can be arranged on the substrate used as the central member.

【0008】

The excitation detecting means causes the four vibrating arms to flex and vibrate on the plane in which they are arranged, centering on the central member. At this time, since the adjacent vibration arms are arranged radially so as to be orthogonal to each other, a force acts in the direction of rotation as a whole due to the vibration of the vibration arms. However, since the weight arm is formed between the vibration arms, the weight is used in the direction opposite to the vibration direction of the vibration arm so that the force acts in the direction in which the rotational force due to the vibration of the vibration arm is offset. The arm vibrates. When rotating around the axis of the vibration arm, the vibration direction of the vibration arm changes due to the Coriolis force, and a signal corresponding to the Coriolis force is output from the excitation detecting means. Here, since the four vibration arms are arranged so as to be orthogonal to each other, it is possible to obtain a signal corresponding to the angular velocity with respect to the two orthogonal directions. In this vibration gyro, an excitation detecting means is formed by a piezoelectric body and an electrode formed on the piezoelectric body, but the vibration arm itself may be formed of a piezoelectric body, or a piezoelectric element different from the vibration arm. Can also be used as an excitation detecting means. That is, the excitation detecting means is formed by having a structure capable of generating bending vibration in the vibration arm by the excitation signal and outputting a signal corresponding to the displacement of the vibration arm.

【0009】

The above-mentioned object, other object, feature and advantage of the present invention will be further clarified from the detailed description of the following embodiments of the invention with reference to the drawings.

【0010】

BEST MODE FOR CARRYING OUT THE INVENTION

FIG. 1 is a perspective view showing an example of the vibration gyro of the present invention. The vibrating gyro 10 includes, for example, a central member 12 having a square planar shape. On the same plane including the central member 12, four vibration arms 14a, 14b, 14c, and 14d are formed radially outward from the central member 12. The vibrating arms 14a to 14d are each formed in a rectangular parallelepiped shape, and adjacent ones are arranged so as to be orthogonal to each other. Further, weight arms 16a, 16b, 16c, 16d having a square planar shape are formed between the four vibration arms 14a to 14d. The weight arms 16a to 16d are also arranged radially outward from the central member 12. These central members 12, vibration arms 14a to 14d, and weight arms 16a to 16d are integrally formed.

【0011】

The central member 12, the vibration arms 14a to 14d, and the weight arms 16a to 16d are formed by, for example, joining two piezoelectric substrates 18 and 20. As shown by the arrows in FIG. 1, these piezoelectric substrates 18 and 20 are polarized from, for example, the facing surface side toward the bonding surface side. For example, electrodes are formed on the entire surface of the piezoelectric substrate 18, and the electrodes are divided by grooves 22, 24, and 26.

【0012】

The groove 22 is formed so as to extend from the vibration arm 14a toward the vibration arm 14c at the central portion in the width direction of the vibration arms 14a and 14c. Further, the groove 24 is formed so as to extend from the vibration arm 14b toward the vibration arm 14d at the central portion in the width direction of the vibration arms 14b and 14d. Further, the groove 26 is formed inside the central member 12 so as to divide the vibration arms 14a to 14d. Then, the electrodes 28a, 28b on the vibration arm 14a separated by these grooves 22, 24,26, the electrodes 30a, 30b on the vibration arm 14b, the electrodes 32a, 32b on the vibration arm 14c, and the vibration arm Electrodes 34a and 34b on 14d are used for signal input / output. Further, as shown in FIG. 2, an electrode 36 is formed on the entire surface of the piezoelectric substrate 20. The excitation detecting means is configured by the piezoelectric substrate and the electrodes forming such vibration arms 14a to 14d. An electrode is also formed on the piezoelectric substrate 18 constituting the weight arms 16a to 16d by adopting the manufacturing method as described later, but this electrode is related to the operation of the vibration gyro 10. There is no such thing.

【0013】

To manufacture such a vibrating gyro 10, for example, as shown in FIG. 3, two piezoelectric substrates 18 and 20 are joined, and a plurality of original plates 38 having electrodes formed on both sides are laminated and waxed or the like. A notch 40 is formed in the hardened material with a dicer or the like. The notch 40 forms the vibration arms 14a to 14d and the weight arms 16a to 16d. Then, the vibrating gyro 10 is produced by forming grooves 22, 24, 26 in the electrodes on one surface of each original plate 38 in which the notch 40 is formed. The electrodes on the vibration arms 14a to 14d may be left, and the electrodes in other parts may be removed by etching or the like. At this time, etching is performed so that the electrodes on the vibration arms 14a to 14d are divided into two. In this case, it is not necessary to form grooves 22, 24, 26. That is, if there are electrodes for signal input / output on the vibration arms 14a to 14d, it is not necessary to form electrodes for other parts.

【0014】

In order to use this vibrating gyro 10, a circuit as shown in FIG. 4 is used. In FIG. 4, the electrodes 28a, 28b, 30a, 30b, 32a, 32b, 34a, 34b of the vibration arms 14a to 14d are shown side by side in order to make the connection relationship easy to understand. The entire surface electrode 36 formed on the piezoelectric substrate 20 is connected to a reference potential.

【0015】

Resistors 42, 44, 46, 48 are connected to the electrodes 28b, 30b, 32b, 34b of the vibration arms 14a to 14d, respectively. An oscillation circuit 50 is connected between these resistors 42,44,46,48 and the electrodes 28a, 30a, 32a, 34a. Further, the electrodes 28b and 32b of the vibration arms 14a and 14c are connected to the differential circuit 52, and the differential circuit 52 is connected to the synchronous detection circuit 54. Further, the synchronous detection circuit 54 is connected to the smoothing circuit 56, and the smoothing circuit 56 is connected to the DC amplifier circuit 58. Similarly, the electrodes 30b and 34b of the vibration arms 14b and 14d are connected to another differential circuit 60, and the differential circuit 60 is connected to the synchronous detection circuit 62. Further, the synchronous detection circuit 62 is connected to the smoothing circuit 64, and the smoothing circuit 64 is connected to the DC amplifier circuit 66.

【0016】

The output signals from the electrodes 28a, 30a, 32a, 34a of the vibration arms 14a to 14d are fed back to the oscillation circuit 50. The feedback signal is amplified by the oscillation circuit 50 and further phase-adjusted to form an excitation signal. This excitation signal is given to the electrodes 28b, 30b, 32b, 34b of the vibration arms 14a to 14d. As a result, the vibrating arms 14a to 14d flex and vibrate in the same plane as shown by the solid and dotted arrows in FIG. At this time, since the vibration arms 14a to 14d vibrate in the same rotation direction, a force acts on the vibration gyro 10 in the rotation direction. However, the weight arms 16a to 16d vibrate in a direction that cancels the rotational force due to the vibration of the vibration arms 14a to 14d, and the rotational force does not work as a whole of the vibration gyro 10.

【0017】

At this time, since the bending states of the vibration arms 14a to 14d are the same, the signals output from the electrodes 28b, 30b, 32b, and 34b are the same. Therefore, no signal is output from the differential circuits 52 and 60. Therefore, it can be seen that the angular velocity is not added to the vibrating gyro 10. In such a vibrating state, when rotating around an axis passing through the vibrating arm 14a and the vibrating arm 14c, a Coriolis force acts in a direction orthogonal to the vibrating direction of the vibrating arms 14a and 14c as shown in FIG. .. At this time, since the Coriolis force does not act on the other vibration arms 14b and 14d, the vibration directions of these vibration arms 14b and 14d do not change.

【0018】

Coriolis forces in opposite directions act on the vibrating arms 14a and 14c, as shown by the solid and dotted arrows in FIG. Therefore, the vibration arms 14a and 14c are displaced in the opposite directions, and signals corresponding to the displacements are output from the electrodes 28b and 32b. Therefore, the signals output from the electrodes 28b and 32b include signals of opposite polarity corresponding to the Coriolis force. When such a signal is input to the differential circuit 52, a large signal corresponding to the Coriolis force is output from the differential circuit 52.

【0019】

The output signal of the differential circuit 52 is detected in the synchronous detection circuit 54 in synchronization with the signal of the oscillation circuit 50. As a result, a signal obtained by inverting either the positive or negative portion of the output signal of the differential circuit 52 or the positive or negative portion is detected. The detected signal is smoothed by the smoothing circuit 56, and further amplified by the DC amplifier circuit 58. Since the output signal of the differential circuit 52 has a level corresponding to the Coriolis force, the level of the output signal of the DC amplifier circuit 58 also corresponds to the Coriolis force, and the angular velocity is different from the output signal level of the DC amplifier circuit 58. The size can be detected. Further, when the direction of the angular velocity applied to the angular velocity sensor 10 is opposite, the polarity of the signal detected by the synchronous detection circuit 54 is opposite. Therefore, the polarity of the output signal of the DC amplifier circuit 58 is also reversed, and the direction of the angular velocity can be detected by the polarity of the output signal of the DC amplifier circuit 58.

【0020】

Further, when the vibration arm 14b and the vibration arm 14d are rotated around the axis, the Coriolis force is applied to the vibration arms 14b and 14d in the same manner as when the vibration arm 14a and 14c are rotated around the axis. work. At this time, the Coriolis force does not act on the vibration arms 14a and 14c. Therefore, the differential circuit 60, the synchronous detection circuit 62, the smoothing circuit 64, and the DC amplifier circuit 66 can detect the angular velocity around the axis passing through the vibration arms 14b and 14d.

【0021】

In this way, the vibrating gyro 10 can detect the angular velocity around two orthogonal axes. Moreover, in order to excite the basic vibrations on the vibration arms 14a to 14d, only one oscillation circuit 50 needs to be used, and the cost can be reduced as compared with the conventional method using two oscillation circuits.

【0022】

In the vibration gyro 10 shown in FIG. 1, the central member 12, the vibration arms 14a to 14d, and the weight arms 16a to 16d are integrally formed, but these may be individually formed. In this case, for example, as shown in FIG. 7, the vibration arms 14a to 14d and the weight arms 16a to 16d individually formed on the base 70 are arranged with the base 70 as the central member. Here, it is preferable that the base 70 uses the same material as the vibration arm, the weight arm, and the like. In order to use the entire surface electrodes 36 of the vibration arms 14a to 14d adhered to the base 70 as a common electrode, for example, electrodes are formed on the entire surface or the upper surface of the base 70 and formed on the base 70. The electrode may be connected to the reference potential.

【0023】

In order to manufacture such a vibrating gyro 10, as shown in FIG. 8, the original plate 38 in which the piezoelectric substrates 18 and 20 are joined to form electrodes on both sides is adhered on the base 70. Then, the original plate 38 is cut by a dicer or the like so that the vibration arms 14a to 14d and the weight arms 16a to 16d are separated. Further, by forming a groove in the electrodes formed on the upper surfaces of the vibration arms 14a to 14d, two excitation detection electrodes are formed on the respective vibration arms 14a to 14d. In FIG. 7, since each part is formed by cutting the original plate 38, the central portion 38a of the original plate 38 remains, but even without this central portion 38a, the angular velocity is detected by the vibrating gyro 10. can do.

【0024】

Further, when the central member 12, the vibration arms 14a to 14d and the weight arms 16a to 16d are integrally formed of the piezoelectric material, the whole may be formed into a disk shape as shown in FIG. Further, as shown in FIG. 10, the vibration arms 14a to 14d and the weight arms 16a to 16d may have the same shape. In this case, adjacent vibration arms 14a to 14d and weight arms 16a to 16d are arranged at an angle of 45 °. Further, as shown in FIG. 11, for example, the fan-shaped vibration arms 14a to 14d and the weight arms 16a to 16d may be adhered to the circular base 70. In this case as well, similarly to the vibration gyro shown in FIG. 10, adjacent vibration arms 14a to 14d and weight arms 16a to 16d are arranged at an angle of 45 °.

【0025】

Further, the central member 12, the vibration arms 14a to 14d and the weight arms 16a to 16d can be integrally formed of a metal plate or the like. In this case, as shown in FIG. 12, the piezoelectric elements 72a, 72b, 72c, 72d are formed on the vibration arms 14a to 14d. In these piezoelectric elements 72a to 72d, an electrode divided into two in the width direction is formed on one surface side of one piezoelectric substrate polarized in the thickness direction, and an electrode is formed on the entire surface on the other surface side. It is a thing. Then, the entire surface electrode formed on the other surface side of the piezoelectric substrate is adhered to the vibration arms 14a to 14d. Even in such a vibration gyro 10, bending vibration is performed in the same plane as the vibration arms 14a to 14d by connecting the entire surface electrodes of the piezoelectric elements 72a to 72d to the reference potential and using the divided electrodes for excitation detection. Can be generated, and the angular velocity can be detected using the circuit shown in FIG.

【0026】

Further, when the central member 12, the vibration arms 14a to 14d and the weight arms 16a to 16d are integrally formed of a metal plate, even if the piezoelectric element 74 is adhered to the central member 12, as shown in FIG. Good. In this piezoelectric element 74, two square-shaped piezoelectric substrates are joined to form an electrode divided into eight on one surface side, and an electrode is formed on the entire surface on the other surface side. Of the eight electrodes, the electrodes 76a, 76b, electrodes 78a, 78b, electrodes 80a, 80b, and electrodes 82a, 82b formed in the portions corresponding to the respective vibration arms 14a to 14d vibrate. Used for vibration detection of the arm 14a to 14d. Even in such a vibration gyro 10, the vibration arms 14a to 14d can be vibrated on the same surface by using the electrodes corresponding to the vibration arms 14a to 14d and using the circuit shown in FIG. , It is possible to detect the angular velocity around the axes in two directions.

【0027】

In the vibration gyro 10 using a metal plate or the like as shown in FIGS. 12 and 13, the vibration arms 14a to 14d and the weight arms 16a to 16d have a disk shape as shown in FIGS. 9 and 10. May be formed in.

【0028】

[Effect of the invention]

According to the present invention, one vibrating gyro can detect angular velocities centered on axes in two directions. Further, the vibrating gyro can be excited by one oscillation circuit, and the cost can be reduced as compared with the conventional method using two vibrating gyros.

[Simple explanation of drawings]

[Figure 1]

It is a perspective view which shows an example of the vibration gyro of this invention.

[Figure 2]

It is a perspective view which shows the other side of the vibrating gyro shown in FIG.

[Fig. 3]

It is a schematic diagram which shows the method of manufacturing the vibrating gyro shown in FIG.

[Fig. 4]

It is a block diagram which shows the circuit for using the vibration gyro shown in FIG.

[Fig. 5]

It is a schematic diagram which FEM analyzed the movement when the vibration gyro shown in FIG. 1 is making a fundamental vibration.

[Fig. 6]

It is a schematic diagram of FEM analysis of the movement when an angular velocity is applied to the vibrating gyro shown in Fig. 1.

[Fig. 7]

It is a top view which shows another example of the vibration gyro of this invention.

[Fig. 8]

It is a schematic diagram which shows the method of manufacturing the vibrating gyro shown in FIG.

[Fig. 9]

It is a perspective view which shows the modification of the vibration gyro shown in FIG.

[Fig. 10]

It is a perspective view which shows the other modification of the vibration gyro shown in FIG.

[Fig. 11]

It is a top view which shows the modification of the vibration gyro shown in FIG.

[Fig. 12]

It is a perspective view which shows another example of the vibration gyro of this invention.

[Fig. 13]

It is a perspective view which shows the modification of the vibration gyro shown in FIG.

[Fig. 14]

It is a perspective view which shows an example of the conventional vibration gyro.

[Fig. 15]

It is a block diagram which shows the circuit for using the conventional vibration gyro shown in FIG.

[Fig. 16]

It is a perspective view which shows another example of the conventional vibrating gyro.

[Explanation of symbols]

10 Vibrating gyro 12 Central member 14a ~ 14d Vibration arm 16a ~ 16d Weight arm 18,20 Piezoelectric substrate 28a, 28b electrodes 30a, 30b electrodes 32a, 32b electrodes 34a, 34b electrodes 36 electrodes 70 bases 72a ~ 72d Piezoelectric element 74 Piezoelectric element