JPH09304081A - Vibrator for piezoelectric vibration angle-velocity meter - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a vibrator for a piezoelectric vibration angle-velocity meter without impairing vibrating characteristics even in small size by constituting a support member of conductive resin, and adhering the vibrator to the member with the adhesive. SOLUTION: First and second piezoelectric members 2, 3 are laminated via a reference electrode 4, and a drive electrode 5 is formed on the opposed surface to the laminated surface of the member 3. Detecting electrodes 7, 8 are formed on the surfaces of the bank parts of both the ends of the vibrator 1, and a feedback electrode 9 is formed on the surface of the bank part sandwiched between the two stripes of grooves 6. A board 10 is a glass epoxy board with a copper pattern, and support members 11, 12 are adhered to the surface with the pattern by silicon adhesive. The materials of the members 11, 12 is conductive silicone rubber. The both of the members 11, 12 or the upper surface of the member 11 is covered with the conductive adhesive, and fixed with the part of the electrode 5.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vibrator of a piezoelectric vibrating angular velocity meter for measuring the rotational angular velocity of an object by detecting the piezoelectric voltage generated by Coriolis force.

[0002]

2. Description of the Related Art A piezoelectric vibrating angular velocity meter measures the rotational angular velocity from the Coriolis force generated when a columnar vibrator is excited and driven at its resonance frequency and the vibrator rotates about its major axis. Taking advantage of its small size, its application to an image stabilizer for still cameras and video cameras is being carried out or studied.

The vibrator is usually fixed to the substrate via a supporting member. The columnar vibrator has its major axis parallel to the substrate and is fixed to the substrate at two nodal points in the resonant vibration of the oscillator. Here, the node refers to a portion where the amplitude is zero or minimum in the vibrator that resonates. As a method of supporting the vibrator, the vibrator and the support member are joined together, and the support member and the substrate are joined together.

Generally, each electrode such as an excitation drive electrode and a piezoelectric voltage detection electrode corresponding to Coriolis force is provided on the surface of the vibrator. A part of the electrode serves as a joint surface. or,
Generally, each electrode is electrically connected to a processing circuit or a ground terminal by a lead wire connected to the electrode.

[0005]

The above-mentioned support member includes:
Conventionally, materials such as metal and resin have been used, but since metal has a high elastic modulus and a large rigidity, the vibration characteristics of the vibrator may be impaired. On the other hand, resin is suitable in terms of vibration characteristics because it has a relatively low elastic modulus, but unlike metal, it has low electrical conductivity. Further, although an adhesive is used for joining, the usual adhesive is also an electric insulator. Therefore, it becomes impossible to connect the lead wire to the electrode joined to the resin support member at a node which is a joining portion. Inevitably, the lead wire had to be soldered in the vicinity of the node, so that the weight of the soldered portion hindered the stability of the vibration mode of the vibrator.

The above-mentioned various problems become apparent as the size of the vibrator becomes smaller. An object of the present invention is to provide a vibrator of a piezoelectric vibrating gyrometer that does not impair vibration characteristics even if the vibrator is small.

[0007]

In order to fix a vibrator to a substrate via a support member, it is ideal that both the vibrator support position and the lead wire soldering position are vibration nodes. . Therefore, the invention according to claim 1 of the present invention relates to "a quadrangular prism-shaped piezoelectric vibrating gyroscope vibrator capable of vibrating in two directions perpendicular to each other, the vibrator being a substrate at a node point of the resonance vibration. The supporting member for fixing is made of conductive rubber, and the conductive adhesive is used as the adhesive for joining the vibrator and the supporting member. " According to a second aspect of the present invention, in the "first aspect, the support member is made of conductive silicone rubber, and the conductive silicone adhesive is used as an adhesive for joining the vibrator and the support member. I was there. "

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 2 is a perspective view for explaining a vibrator used in the present invention. Transducer 1 is PZT
A first piezoelectric member 2 and a second piezoelectric member 3 made of (lead zirconate titanate) are attached to each other with a reference electrode 4 interposed therebetween. A drive electrode 5 for exciting the vibrator 1 is formed on the entire surface of the second piezoelectric member 3 facing the bonding surface. In addition, on the surface of the first piezoelectric member 2 facing the bonding surface, two groove portions 6 are formed parallel to the length direction of the vibrator, and on the surface of the bank at both ends of the vibrator 1. The detection electrodes 7 and 8 are formed, and a feedback electrode 9 is formed on the surface of the bank between the two groove portions 6.
Are formed.

The vibrator 1 has a width of 1.0 mm and a thickness of 1.0.
The groove 6 has a width of 0.2 mm and a depth of 30 μm, and each of the detection electrodes 7 and 8 and the feedback electrode 9 has a width of 0.2 mm. To drive the vibrator 1 for excitation, an AC voltage is applied to the drive electrode 5. Vibrator 1
Bending motion occurs in which unevenness occurs in the direction perpendicular to the bonding surface. Normally, by using a self-exciting circuit (not shown), the vibrator 1 vibrates at the drive side resonance frequency.

Now, assuming that the vibrator 1 rotates at a certain angular velocity around an axis parallel to the length direction of the vibrator 1, the vibrator 1 vibrates in the width direction at the resonance frequency on the detection side, and The Coriolis force component is superimposed on the signal at the resonance frequency. Since the Coriolis force component modulates the amplitude of the signal based on the resonance frequency on the detection side in opposite phase to the detection electrodes 7 and 8, only the Coriolis force component is obtained by taking the differential between the waveforms output to the detection electrodes 7 and 8. Can be detected. FIG.
FIG. 3 is a perspective view showing a state where the vibrator 1 shown in FIG. 2 is installed on a substrate 10. The vibrator 1 is installed on the substrate 10 via the two support members 11 and 12 provided at the node positions.

The substrate 10 is a commonly used glass-epoxy substrate with a copper pattern and has a size of 15
× 20mm, thickness 0.8mm. The copper pattern has contacts 4b, 5b, 7 for wiring to a processing circuit or a ground terminal.
b, 8b, 9b are included. The positions of these contacts can be selected from various arrangements depending on the positional relationship between the vibrator and the processing circuit.

Support members 11 and 12 are adhered to the surface of the substrate 10 on which the copper pattern is provided by a silicone adhesive. The dimensions of the supporting members 11 and 12 are 0.5 mm in width and height.
It is a rectangular parallelepiped with a length of 0.1 mm and a length of 3 mm, but is not limited to this size or shape. The material of the support members 11 and 12 is a conductive silicone rubber (KE-E made by Shin-Etsu Silicone).
3492), and its resistance value is 2Ω. A conductive silicone adhesive is applied to the upper surface of both of the support members 11 and 12 or the one to which the lead wire is attached (support member 11 in this figure), and a part of the drive electrode 5 of the vibrator 1 is fixed. To be done. Since the support member 11 is electrically connected to the contact 5b, the drive electrode 5 is electrically connected to the output side of the self-excitation circuit (not shown).

Lead wires 7a and 8a are soldered to the node positions of the detection electrodes 7 and 8, respectively.
The other ends of a and 8a are soldered to the contacts 7b and 8b, respectively. Therefore, the voltage signal detected by the detection electrodes 7 and 8 is electrically connected to the detection circuit (not shown).
Similarly, the lead wire 9a is soldered to the feedback electrode 9 at the node position, and the other end of the lead wire 9a has a contact point 9a.
Soldered to b. Therefore, the feedback electrode 9 is electrically connected to the input side of the self-exciting circuit (not shown).

Similarly, the lead wire 4a is also soldered to the reference electrode 4 at its node position, and the other end of the lead wire 4a is
Soldered to the contact 4b. Therefore, the reference electrode 4 has the ground potential. As described above, each electrode of the vibrator is connected to the processing circuit such as the self-excitation circuit or the detection circuit or the ground terminal. The resistance value of the conductive silicone rubber used in this example is 2Ω, and the resistance value of the vibrator at resonance is 2 kΩ.
Since it is sufficiently small, the problem of voltage drop does not occur. Further, the conductive silicone adhesive used in this embodiment is thinly applied to the upper surface of the support member 11 to a thickness of about 10 μm and cured after being bonded to the vibrator 1, so that the resistance value is negligible. Small.

The Q value of the vibrator manufactured according to the present invention is 1
It was 50, and a sufficient resonance amplitude was obtained, and the angular velocity could be measured with high accuracy by the piezoelectric vibration angular velocity meter using the vibrator.

[0016]

According to the vibrator for a piezoelectric vibrating angular velocity meter of the present invention, the support member is made of a conductive resin, and the vibrator and the support member are bonded with a conductive adhesive, so that the node position It was possible to realize both the vibrator holding and contact function at the same time. As a result, the vibration characteristics are not impaired. This effect is more remarkable as the size of the vibrator is smaller.

[Brief description of drawings]

FIG. 1 is a perspective view showing a vibrator according to an embodiment of the invention.

FIG. 2 is a perspective view showing an installation state of a vibrator according to the embodiment of the invention on a substrate.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Oscillator 2 ... 1st piezoelectric member which comprises an oscillator 3 ... 2nd piezoelectric member which comprises an oscillator 4 ... Reference electrode 5 ... ..Driving electrodes 6 ... grooves 7,8 ... detection electrodes 9 ... feedback electrodes 10 ... substrate 11 and 12 support members

Claims (2)

[Claims] 1. A vibrator for a piezoelectric vibrating gyroscope, which is in the shape of a quadrangular prism and is capable of vibrating in two directions perpendicular to each other. A vibrator for a piezoelectric vibrating angular velocity meter, characterized in that the adhesive for bonding the vibrator and the support member is made of a conductive rubber, and the adhesive is a conductive adhesive. 2. The vibrator for a piezoelectric vibration angular velocity meter according to claim 1, wherein the support member is made of conductive silicone rubber, and the adhesive is a conductive silicone adhesive.