WO2007088747A1

WO2007088747A1 - Support structure of vibrator and its manufacturing method

Info

Publication number: WO2007088747A1
Application number: PCT/JP2007/050937
Authority: WO
Inventors: Katsumi Fujimoto
Original assignee: Murata Manufacturing Co., Ltd.
Priority date: 2006-02-01
Filing date: 2007-01-23
Publication date: 2007-08-09

Abstract

To provide a support structure of a vibrator used as a vibrating gyroscope and its manufacturing method. The vibrating gyroscope (10) comprises a tuning-fork type vibrator (12) and a substrate. Slits (22a, 22b) are formed in the upper surface of the tuning-fork type vibrator (12), and detection electrodes (24a, 24b) and a drive electrode (26) are provided on the upper surface of the turning-fork vibrator. The detection electrodes (24a, 24b) and the drive electrode (26) are connected to terminals (32a, 32b, 34a, 34b) provided on the substrate through wires (28a, 28b, 30a, 30b). The connection is performed by wire bonding. Annealing treatment is applied to the wires (28a, 28b, 30a, 30b) for diffusing internal stress, and plating treatment is applied thereto to provide rigidity. The wires (28a, 28b, 30a, 30b) fixedly support the tuning-fork type vibrator (12) and have functions for inputting/outputting signals.

Description

Specification

Vibrator support structure and manufacturing method thereof

Technical field

TECHNICAL FIELD [0001] The present invention relates to a support structure for a vibrator and a method for manufacturing the same, and more particularly to a support structure for supporting a vibrator used as, for example, a vibration gyro and the manufacturing method therefor.

Background art

[0002] When a tuning fork vibrator is supported, it is installed on the substrate with a support member provided at the base of the tuning fork, and signal input / output is performed by separately attaching lead wires (wires) to each electrode. It has a pull-out structure (for example, see Patent Document 1).

That is, the support member is bonded and fixed on the substrate. A base that connects the two legs of the tuning fork resonator is fixed to the support member. The tuning fork vibrator is installed so that the plane on the substrate and the plane of the tuning fork vibrator are parallel. The tuning fork vibrator and the terminals provided on the substrate are electrically connected by lead wires. A drive signal is input via the lead wire, and a signal detected by the tuning fork vibrator is output.

According to such a support structure in a tuning fork type gyro, the drive vibration surface of the vibrator can be arranged parallel to the base, and the size can be reduced during knocking.

[0003] When a sound piece type vibrator is supported, a structure is disclosed in which a support pin as a support member also serves as an electrode extraction function (see, for example, Patent Document 2).

That is, as shown in FIG. 5, the sound piece type vibrator 1 includes a columnar vibrator 2. The vibrating body 2 is formed by joining two piezoelectric substrates 3a and 3b. The piezoelectric substrates 3a and 3b are polarized in the thickness direction so as to be opposite to each other. Divided electrodes 4a and 4b are formed on one main surface of the vibrating body 2 so as to be divided in the width direction. Further, a full-surface electrode is formed on the other main surface of the vibrating body 2.

In the vicinity corresponding to the two node points of the bending vibration of the vibrating body 2, the support member 5 and the support member 6 are connected to the divided electrodes 4a and 4b, respectively. Ma Further, in the vicinity corresponding to the two node points, the support member 7 and the support member 8 are connected to the entire surface electrode of the vibrator 2. The ends of these support members 5, 6, 7, and 8 are fixed to the substrate 9.

According to such a support structure for a sound piece type gyro, panel support is provided to the four support members 5, 6, 7, and 8, thereby preventing support damping and providing a signal input / output function. Therefore, it is possible to reduce the change in characteristics between the adjustment of characteristics before the cover is mounted and the completion after the cover is mounted. Therefore, when the sound piece type vibrator 1 is used as a vibration gyro, variation in characteristics of the vibration gyro can be reduced. In addition, since a thin mounting board can be used, the height of the vibration gyro can be reduced.

Patent Document 1: Japanese Patent Application Laid-Open No. 11 51658

Patent Document 2: Japanese Patent Laid-Open No. 2003-279355

Disclosure of the invention

Problems to be solved by the invention

[0005] However, when supporting the tuning fork type vibrator with a force, it is necessary to prepare a support member for supporting and fixing the structural force and a wire for signal input / output. In addition, when the vibrator is used as a vibrating gyroscope, torsional vibration is generated in the vibrator, so the resonance frequency and resonance resistance change depending on how the tuning fork vibrator is fixed. The weight of the fixed part of the base must be sufficiently large compared to the tuning fork vibrator. In addition, as the vibrator for detecting the angular velocity is reduced in size, the electrode force formed on the surface thereof, for example, the connection to the circuit unit, the positional accuracy of the support, and the stress contained in the support structure, reach the resonance characteristics. There was an effect.

On the other hand, since a sound piece type vibration gyro performs both support of the vibrator and signal input / output by a support member such as a support pin, it is necessary to devise various means for the structure of the support member. Since the structure becomes complicated, the cost of the support member has increased.

[0006] Therefore, a main object of the present invention is to obtain a vibrator support structure capable of supporting a vibrator and inputting / outputting signals with a simple structure, and such a vibrator support structure. It is to provide a manufacturing method that can be used. Means for solving the problem

[0007] The vibrator support structure according to the present invention includes a substrate, a vibrator mounted on the board, and the substrate and the vibrator connected by shear bonding, for signal input / output and the vibrator. A wire is used for supporting the vibrator, and the wire is annealed at least in part, and at least part of the wire is a support structure of the vibrator. By diffusing the stress, the positional accuracy of the vibrator is improved. In addition, it is possible to give rigidity to the wire and to provide panel properties as a support member by the plating process.

[0008] In addition, the vibrator support structure according to the present invention is characterized in that the vibrator is supported by a wire in a non-contact state with the substrate. It is a structure.

By supporting the vibrator with a wire in the air, the vibrator can be vibrated in a form close to free vibration and damping of the vibration of the vibrator can be prevented.

[0009] A method for manufacturing a vibrator support structure according to the present invention includes a step of preparing a vibrator provided on an upper surface together with a substrate, a step of fixing the vibrator on a substrate with a fixing material, A step of wire bonding with a wire to connect the connected terminal and an electrode provided on the vibrator, a step of annealing the at least part of the wire, and a step of subjecting at least a part of the wire to the plating process And a step of deleting the fixing material. A method for manufacturing a support structure for a vibrator.

By fixing the vibrator with a fixing material on the substrate, wire bonding can be performed between the vibrator and the substrate. In addition, by removing the fixing material, it is possible to manufacture the vibrator so that it is supported in the air.

[0010] A method for manufacturing a vibrator support structure according to the present invention includes a step of preparing a vibrator provided on an upper surface together with a substrate, and a step of holding the vibrator in a suspended state by a jig on the substrate. Wire bonding with a wire to connect the terminal provided on the substrate and the electrode provided on the vibrator, annealing the at least part of the wire, and at least part of the wire Process to remove the jig and remove the jig And a method of manufacturing a vibrator support structure.

Wire bonding is possible by suspending the vibrator in the air with a jig. In addition, by removing the jig, the vibrator can be manufactured to be supported in the air.

[0011] According to the support structure of the vibrator that is useful in the present invention, both the support fixing and signal input / output functions of the vibrator can be provided by a wire bonding wire. In addition to supporting the vibrator, it is possible to input and output signals. Further, since the vibrator is held in the air by the wire, it is possible to support the vibrator in a form close to damping free. In addition, according to the method for manufacturing a support structure for a vibrator according to the present invention, the above-described support structure can be easily obtained using wire bonding technology.

The above-described object, other objects, features, and advantages of the present invention will become more apparent from the following description of the best mode for carrying out the invention with reference to the drawings.

Brief Description of Drawings

FIG. 1 is a perspective view of a vibration gyro using a vibrator support structure according to an embodiment of the present invention.

FIG. 2 is a perspective view of another vibration gyro using the support structure for the vibrator according to the embodiment of the present invention.

FIG. 3 is a perspective view showing an example in which the support structure of the vibrator in the embodiment of the present invention is applied to still another vibration gyro.

FIG. 4 is an illustrative view of a method for manufacturing the vibration gyro shown in FIG. 3 using, for example, a sound piece type vibrator in the embodiment of the present invention.

FIG. 5 is a perspective view showing a conventional example that works on the support structure of the vibrator.

Explanation of symbols

[0014] 10, 110, 210 Vibrating gyro

12, 112 Tuning fork type vibrator

14, 42 First piezoelectric substrate 16, 44 Second piezoelectric substrate

18 Connecting part

20 Bonding layer

22a, 22b

24a, 24b detection electrode

26 Drive electrode

28a, 28b, 30a, 30b wire

32a, 32a, 34a, 34b terminals

40 sound piece type vibrator

50 First division plane

52 Second split surface

54 PCB

56 Fixing material

BEST MODE FOR CARRYING OUT THE INVENTION

FIG. 1 is a perspective view of a vibrating gyroscope using a vibrator support structure according to an embodiment of the present invention. The vibrating gyroscope 10 includes a tuning fork vibrator 12. The tuning fork vibrator 12 is formed by joining a tuning fork-shaped first piezoelectric substrate 14 and a second piezoelectric substrate 16. A connecting portion 18 is formed on one end side of each leg portion. The first piezoelectric substrate 14 and the second piezoelectric substrate 16 are bonded by a bonding layer 20 such as epoxy resin. The first piezoelectric substrate 14 and the second piezoelectric substrate 16 are polarized in thickness directions opposite to each other. Then, slits 22a and 22b are formed on the upper surface of the first piezoelectric substrate 14 in the longitudinal direction.

[0016] The upper surface of the tuning fork vibrator 12 is divided into three regions with the slits 22a and 22b as boundaries. Detection electrodes 24a and 24b are formed on both end surfaces of the upper surface of the tuning fork vibrator 12, that is, outside the slits 22a and 22b. A substantially U-shaped drive electrode 26 is formed on the inner surface of the tuning fork vibrator 12 with the slit 22a and the slit 22b as the boundary. Further, a full-surface electrode is formed on the lower surface of the tuning fork vibrator 12. One end portion of the wires 28a and 28b is connected to the detection electrodes 24a and 24b. Further, one end portion of the wires 30a and 30b is connected to the drive electrode 26.

[0017] The wires 28a, 28b, 30a, 30b have a support function for supporting the tuning fork vibrator 12, and a function for transmitting a drive signal and an input / output signal of a detection signal from the tuning fork vibrator 12. I have.

The wire 28a and the wire 28b are formed by being bent into a substantially S shape in order to form elasticity. The other ends of the wires 28a and 28b are connected to the terminals 32a and 32b. The terminals 32a and 32b are provided on a substrate (not shown) having a plane parallel to the entire electrode forming surface of the tuning fork vibrator 12 and having an appropriate distance from the tuning fork vibrator 12.

Further, the wire 30a and the wire 30b connect the drive electrode 26 and the terminals 34a and 34b. The wire 30a and the wire 30b are also formed by being bent into a substantially S shape in order to form elasticity. The other ends of the wires 30a and 30b are connected to the terminals 34a and 34b. The terminals 34a and 34b are provided on a substrate (not shown) at the end of the tuning fork vibrator 12 on the leg side.

Connection of the detection electrodes 24a, 24b and the drive electrode 26 of the tuning fork vibrator 12 to the terminals 32a, 32b, 34a, 34b of the substrate by the wires 28a, 28b, 30a, 30b is performed by wire bonding.

The wires 28a, 28b, 30a, 30b are subjected to, for example, thermal annealing or hydrogen annealing in order to diffuse internal stress in the wires 28a, 28b, 30a, 30b. By eliminating the internal stress of the wires 28a, 28b, 30a, 30b, the tuning fork vibrator 12 does not move, and the position accuracy of the tuning fork vibrator 12 is ensured. Furthermore, Ni plating is applied to the wires 28a, 28b, 30a and 30b, and panel characteristics are imparted by increasing the rigidity.

[0018] In the vibrating gyroscope 10, a signal is applied between the drive electrode 26 and the detection electrodes 24a and 24b, so that the leg of the tuning fork vibrator 12 vibrates so as to open and close. At this time, since the two legs of the tuning fork vibrator 12 vibrate in the same state with respect to the polarization direction, the signals output from the detection electrodes 24a and 24b are the same. Therefore, if the difference between the output signals of the detection electrodes 24a and 24b is taken, the output becomes zero.

In this state, the rotational angular velocity is about the axis parallel to the two legs of the tuning fork vibrator 12. When applied, Coriolis works in a direction perpendicular to the vibration at no rotation. By this Coriolica

Then, the vibration direction of the two legs of the tuning fork vibrator 12 changes to a vibration that intersects each other. Therefore, the signals output from the detection electrodes 24a and 24b are signals with opposite phases. Therefore, if the difference between the output signals of the detection electrodes 24a and 24b is taken, a large signal corresponding to Coriolis can be obtained.

Since the level of the output signal from the detection electrodes 24a, 24b is determined by the magnitude of the displacement of the leg of the tuning fork vibrator 12, the level of the output signal increases when a large Coriolis is activated. Therefore, the magnitude of the rotational angular velocity can be detected based on the level of the output signal.

[0020] According to the tuning fork type gyro support structure of the present invention, the back surface of the tuning fork type vibrator 12 can be supported without contacting any part of the substrate, and the tuning fork type vibrator itself is extremely free. Can be put into state.

Therefore, the tuning fork vibrator 12 can vibrate in a state close to damping free. Furthermore, since the tuning fork vibrator 12 and the substrate are connected by wire bonding, a structural material such as a support pin is unnecessary, and a conductive adhesive or the like for connecting the support pin to the vibrator or the substrate can be used. Since solder and its process can be dispensed with, the cost can be reduced.

FIG. 2 is a perspective view of another vibration gyro using the support structure for the vibrator in the embodiment of the present invention. The vibrating gyroscope 110 includes a tuning fork vibrator 112. The tuning fork vibrator 112 has the same configuration as the tuning fork vibrator 12 shown in FIG.

On the upper surface of the first piezoelectric substrate 14, the two detection electrodes 24 a and 24 b are formed close to each other on the connecting portion 18 side of the tuning fork vibrator 12. A substantially U-shaped drive electrode 26 is formed inside the detection electrodes 24a and 24b.

[0022] The wires 28a and 28b electrically connect the detection electrodes 24a and 24b and the terminals 32a and 32b. The connection positions of the detection electrodes 24a and 24b are positions close to each other in the approximate center of the connecting portion 18 of the detection electrodes 24a and 24b. Further, the wire 30a and the wire 30b electrically connect the drive electrode 26 and the terminals 34a and 34b. The connection position is a position close to the central portion of the coupling portion 18 in the drive electrode 26. The wires 28a, 28b, 30a, and 30b are subjected to the same annealing process and plating process as those used in the tuning fork vibrator 12 shown in FIG.

[0023] Thus, in the case of this tuning fork type vibrator 112, when used as a vibrating gyroscope, it is twisted during vibration. Therefore, the tuning fork type vibrator 112 is supported by the wires 28a, 28b, 30a, 30b as a support structure. By gathering the centering position in the center, vibration damping can be further reduced.

FIG. 3 is a perspective view showing an example in which the support structure of the vibrator in the embodiment of the present invention is applied to still another vibration gyro. The vibrating gyroscope 210 includes the sound piece type vibrator 40. The sound piece type vibrator 40 includes a first piezoelectric substrate 42 and a second piezoelectric substrate 44. The first piezoelectric substrate 42 and the second piezoelectric substrate 44 are stacked with a bonding layer 46 interposed therebetween. Further, the first piezoelectric substrate 42 and the second piezoelectric substrate 44 are polarized in opposite thickness directions. A slit 48 is formed on the upper surface of the first piezoelectric substrate 42 so that one end force of the sound piece type resonator 40 extends to the other end, and the upper surface of the first piezoelectric substrate 42 is divided, and the first piezoelectric substrate 42 is divided. A dividing surface 50 and a second dividing direction 52 are formed.

[0025] At approximately the center in the longitudinal direction of the first divided surface 50 and the second divided surface 52 on the upper surface of the first piezoelectric substrate 42, the detection electrodes 24a, 24b is formed.

Further, the drive electrode 26 is formed continuously from the vicinity of the node point on the one end side of the upper surface of the first piezoelectric substrate 42 to one end surface and substantially the entire lower surface of the second piezoelectric substrate 44. .

In addition, the wires 28a, 28b, 30a, 30b are connected to the terminals 32a, 32b on the detection electrode 24a, 24b force S substrate as in FIG. 1, and the drive electrode 26 is connected to the terminals 34a, 34b on the substrate. The The detection electrodes 24a, 24b and the horse motion moving electrode 26 and the wires 28a, 28b, 30a, 30b are connected in the vicinity of the node point of the sound piece type vibrator 40. Connection of the detection electrodes 24a, 24b and the horse motion electrode 26 with the wires 28a, 28b, 30a, 3 Ob and the terminals 32a, 32b, 34a, 34b is performed by wire bonding. Further, the wires 28a, 28b, 30a, 30b have a function of supporting the sound piece type vibrator 40 and a function of signal input / output. These wires 28a, 28b, 30a, 30b are subjected to annealing and plating. In the vibrating gyroscope 210, a drive signal is given to the drive electrode 26 via the wires 30a and 30b. At this time, since the two piezoelectric substrates 42 and 44 are polarized in directions opposite to each other, when the first piezoelectric substrate 42 is extended by the drive signal, the second piezoelectric substrate 44 contracts. On the other hand, when the first piezoelectric substrate 42 contracts, the second piezoelectric substrate 44 expands. For this reason, the sound piece type vibrator 40 bends and vibrates in a direction orthogonal to the electrode formation surface.

[0027] At this time, since the vibration state of the sound piece type vibrator 40 in the detection electrode 24a, 24b formation portion is the same, the same signal is output from the detection electrodes 24a, 24b. Therefore, if the difference between these signals is taken, the output will be zero. When rotating around the axis of the sound piece type vibrator 40 in such a state, the vibration direction of the sound piece type vibrator 40 is changed by the Coriolis force. Therefore, a difference occurs in the vibration state of the sound piece type vibrator 40 in the detection electrode 24a, 24b formation portion, and the signal output from the detection electrode 24a, 24b also changes. At this time, the signals output from the detection electrodes 24a and 24b increase and decrease in accordance with the amount of change in the vibration direction of the sound piece type vibrator 40. Therefore, the rotational angular velocity is detected by assuming the difference between these signals. can do.

[0028] The sound piece vibrator 40 can also be supported without contacting the back of the sound piece vibrator 40 anywhere on the substrate, and the sound piece vibrator itself is in a very free state. Can be put in.

Next, FIGS. 4 (a) to 4 (e) show a method of manufacturing the vibrating gyroscope shown in FIG. 3 using, for example, a sound piece type vibrator in the embodiment of the present invention.

As shown in FIG. 4 (a), for example, a sound piece type vibrator 40 provided with detection electrodes 24a and 24b and a drive electrode 26 is prepared. The detection electrodes 24 a and 24 b are formed in the longitudinal direction at the approximate center of the upper surface of the sound piece type transducer 40. Further, the drive electrode 26 is formed continuously from the upper surface at one end of the sound piece type transducer 40 to the one end surface and substantially the entire lower surface of the sound piece type transducer 40.

Then, as shown in FIG. 4 (b), the sound piece type transducer 40 is fixed on the substrate 54 by the fixing material 56. The fixing member 56 is formed by using, for example, wax or water-soluble acrylic adhesive. Or, the both ends of the sound piece type transducer 40 may be held in a suspended state by a jig. Then, in the state where the sound piece type vibrator 40 is held, as shown in FIG. 4 (c), the detection electrodes 24a and 24b and the drive electrodes 26 of the sound piece type vibrator 40 and the terminals on the substrate 54 are connected by wire bonding. 32a, 32b, 34a, 34b are connected. When wire bonding is performed, one or a plurality of bent portions are formed to form elasticity in the wires 28a, 28b, 30a, 30b.

Furthermore, as shown in Fig. 4 (d), as shown here, wires 28a, 28b, 30a, 30b [On the other hand, a thermal annealing treatment for diffusing the internal stress of wires 28a, 28b, 30a, 30b, Alternatively, hydrogen annealing is performed. By doing so, the positional accuracy after temporary fixing can be maintained. For example, when the wires 28a, 28b, 30a, and 30b are gold, the longitudinal elastic modulus, which is an index indicating the hardness, is 7560 kgZmm ² , and the maximum is 8120 kgZmm ² by annealing including hydrogen annealing. As a result, the wires 28a, 28b, 30a, 30b become hard and the fixing function is improved.

In addition, by applying current to the wires 28a, 28b, 30a, 30b and increasing the rigidity by Ni plating, the wires 28a, 28b, 30a, 30b are imparted with a “| 4 force”. In other words, when the plating is applied, it hardens at least in proportion to the square of its diameter. Furthermore, when the Ni plating is applied, for example, the longitudinal elastic modulus is 22500 kgZmm ^{2 which} is nearly three times as large, so the synthesized hardness is gold. It becomes larger than a single unit and the effect is superimposed.

After that, as shown in FIG. 4 (e), the fixing member 56 is removed, or the jig is removed and the wire 28a, 28b, 30a, 30b is suspended in the air. The support structure can be manufactured.

Then, according to the method for manufacturing the tuning fork type and sound piece type vibrator support structure, it is possible to place the vibrator itself in a state of being held in a hollow state by a wire that does not contact the back surface of the vibrator anywhere. .

Thus, according to this method for manufacturing a sound piece type vibrator support structure, a vibrator that can both support the vibrator and input / output signals using a simple method called wire bonding. The support structure can be obtained.

Claims

The scope of the claims

[1] a substrate;

A vibrator mounted on the substrate;

By connecting the substrate and the vibrator by wire bonding, including wires used for signal input and output and for supporting the vibrator,

The wire support structure for a vibrator, wherein at least a part of the wire is annealed and at least a part of the wire is subjected to plating.

2. The vibrator support structure according to claim 1, wherein the vibrator is supported by the wire in a non-contact state with the substrate.

[3] A step of preparing a vibrator provided on the upper surface together with the substrate;

Fixing the vibrator with a fixing material on the substrate;

Wire bonding with a wire to connect the terminal provided on the substrate and the electrode provided on the vibrator;

Annealing the at least part of the wire;

A step of subjecting at least a portion of the wire to a mating treatment;

Removing the fixing material;

A method of manufacturing a support structure for a vibrator.

[4] preparing a vibrator provided on the upper surface together with the substrate;

A step of holding the vibrator in a suspended state by a jig on the substrate; and a step of wire bonding with a wire to connect a terminal provided on the substrate and the electrode provided on the vibrator. When,

Annealing the at least part of the wire;

A step of subjecting at least a portion of the wire to a mating treatment;

Removing the jig;

A method of manufacturing a support structure for a vibrator.