JP2006029799A - Piezoelectric device and piezoelectric oscillator - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a piezoelectric device capable of desirable detection by preventing deformations of lead plates holding a piezoelectric oscillating reed when an impact is added to the piezoelectric device and preventing reductions in detection sensitivity due to lead plate deformations. <P>SOLUTION: In a gyroscope sensor 100, which is the piezoelectric device, a gyroscope oscillating reed 10; a plurality of the lead plates 15; and a supporting substrate 18 are housed in a package 20, and a lid 21 is fastened to a fastening surface of the package 20. Lead plate reinforcing parts 16 in which parts of the supporting substrate 18 are extended to a window overhang part 25 of the supporting substrate 18 correspondingly to the leads plate 15 are joined to the lead plates 15. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a piezoelectric device having a piezoelectric vibrating piece such as a gyro vibrating piece and a piezoelectric oscillator including the piezoelectric device.

  For example, in a conventional piezoelectric device as described in Patent Document 1, a gyro vibrating piece 110 as a piezoelectric vibrating piece is fixed to a support substrate 111 with a bonding material 112 as shown in FIG. It is held by 113b and connected by a conductive adhesive 114 or the like. The support substrate 111 is fixed to the package 115 with a fixing material 116.

JP 2003-294450 A

  However, in the piezoelectric device shown in the background art described above, since the strength of each of the lead plates 113a and 113b that support the piezoelectric vibrating piece is weak, the lead plates 113a and 113b are caused by an impact applied to the piezoelectric vibrating piece. It may be deformed and the holding posture of the piezoelectric vibrating piece may change to an unexpected state. Due to the influence on the characteristics due to the change in the holding posture of the piezoelectric vibrating piece, the detection sensitivity of the gyro vibrating piece as an example of the piezoelectric vibrating piece is lowered, and a desired detection cannot be performed.

  The present invention has been made in view of the above problems, and an object of the present invention is to provide a piezoelectric device capable of performing desired detection without causing a decrease in detection sensitivity even when an impact or the like is applied.

In order to solve such a problem, the piezoelectric device of the present invention is connected to the piezoelectric vibrating piece, the support substrate, the piezoelectric vibrating piece and the support substrate to make both conductive, and the piezoelectric device is connected to the support substrate. A lead plate for supporting the piezoelectric vibrating piece in a separated state, and a lead plate reinforcing portion formed by extending a part of the support substrate substantially along the lead plate and joined to the lead plate. And
According to the piezoelectric device of the present invention, since the lead plate reinforcing portion and the lead plate protruding from the support substrate are joined, the rigidity of the lead plate reinforcing portion is added to the stiffness of the lead plate alone, and the joined lead The plate is more rigid than a single lead plate. Therefore, even if an impact or the like is applied to the piezoelectric vibrating piece, the lead plate is hardly deformed. In other words, a change in the holding posture of the piezoelectric vibrating piece is less likely to occur, and a decrease in detection sensitivity of a gyro vibrating piece as an example of the piezoelectric vibrating piece can be prevented.

  In addition, the lead plate reinforcing portion may protrude toward a substantially center of the support substrate.

The tip of the lead plate reinforcing portion is preferably formed between the lead plate and the connecting portion between the piezoelectric vibrating piece.
In this way, since the length of the lead plate reinforcing portion can be shortened, the rigidity of the lead plate reinforcing portion can be ensured. That is, the rigidity with the joined lead plate can be increased.

Further, it is desirable that the lead plate separates the piezoelectric vibrating piece from the support substrate in a bent state.
In this way, the piezoelectric vibrating piece can be easily separated from the support substrate without using other members.

Further, it is preferable that the lead plate and the lead plate reinforcing portion are bent in a state where both are joined, and the piezoelectric vibrating piece is separated from the support substrate.
In this way, since the rigidity of the bent portion of the lead plate that is likely to be deformed can be increased, the lead plate can be made difficult to deform.

Moreover, it is preferable that the support substrate and the lead plate are connected on the surface of the bent lead plate reinforcing portion.
In this case, since the one end of the lead plate is on the surface of the lead plate reinforcing portion, the adjustment of the lead plate in the height direction can be easily performed. Accordingly, it is possible to make the support height of the piezoelectric vibrating pieces of the plurality of lead plates uniform.

The piezoelectric vibrating piece is preferably a gyro vibrating piece used in a gyro sensor for detecting a rotational angular velocity.
In this way, it is possible to provide a gyro sensor capable of preventing a decrease in detection sensitivity and capable of desired detection even in a gyro vibrating piece in which the holding posture of the piezoelectric vibrating piece is greatly influenced by the detection sensitivity. It becomes possible.

  It is also possible to provide a piezoelectric oscillator having the above-described piezoelectric device and a circuit element having a function for driving at least the piezoelectric vibrating piece.

The best mode of a piezoelectric device according to the present invention will be described below with reference to the drawings. The present invention is not limited to the embodiments described later.
(First embodiment)

As a first embodiment of a piezoelectric device according to the present invention, a gyro sensor using a crystal vibrating piece for a gyro sensor (hereinafter referred to as “gyro vibrating piece”) as an example of a piezoelectric vibrating piece will be described with reference to the drawings. . FIG. 1 is a plan view schematically showing the gyro sensor of the first embodiment. FIG. 2 schematically shows the gyro sensor of the first embodiment, and is a cross-sectional view taken along the line AA of FIG.
== Gyro sensor configuration ==

First, the configuration of the gyro sensor will be described. The gyro sensor 100 is mounted and used on the object in order to detect the posture and position of an object such as an electronic device and a vehicle.
As shown in FIGS. 1 and 2, the gyro sensor 100 includes a gyro vibrating piece 10 in a package 20 (in FIG. 1, a part is broken and shown by a two-dot chain line for easy understanding of the drawing). The plate 15 and the supporting substrate 18 are accommodated, and the lid 21 is fixed to the package 20 fixing surface and sealed.

The package 20 is formed of ceramic or the like, and the back surface of the support substrate 18 is fixed to the bottom surface 17 of the recess. The support substrate 18 is formed of an insulating material such as polyimide resin, for example, and a conductive pattern (not shown) is formed on the surface thereof. A punched window opening 25 is formed at the center of the support substrate 18. By punching the window opening 25, a lead plate reinforcing portion 16 is formed so that the support substrate 18 extends to the inside of the window opening 25, and the lead plate 15 is fixed to the lead plate reinforcing portion 16. . One end of the lead plate 15 in the longitudinal direction is connected to the conductive pattern. The gyro vibrating piece 10 is connected to the other end of the lead plate 15 with a bonding material (not shown) such as a conductive adhesive or a gold bump.
== Description of the lead plate ==

  For example, the six lead plates 15 are formed by applying nickel gold plating to a copper thin plate having a thickness of 18 μm and a width of 30 to 100 μm. The lead plate 15 is provided generally from the four side surface directions of the concave portion of the package 20 toward the center of the package 20, that is, the center 27 of the support substrate 18. The lead plate 15 is connected to a conductive pattern (not shown) provided on the surface of the support substrate 18 by a connection portion 22 at one end, and is bent upward at a portion on the center 27 side of the connection portion to form a gap. A forming portion 26 is formed. The gap forming portion 26 provides a gap between the gyro vibrating piece 10 and the support substrate 18 to prevent contact between the gyro vibrating piece 10 and the support substrate 18.

The lead plate 15 is further bent at the other end at the tip of the gap forming portion 26 to form the receiving portion 23 of the gyro vibrating piece 10. An electrode (not shown) of the gyro vibrating piece 10 is electrically connected to the receiving portion 23.
== Description of the lead plate reinforcement ==

  The lead plate reinforcing portion 16 is formed by projecting a part of the support substrate 18 along the corresponding lead plate 15 to a window opening portion 25 formed in the central portion of the support substrate 18. The lead plate reinforcing portion 16 has a shape slightly wider than the width dimension of the corresponding lead plate 15, and the tip 24 is formed in the middle of the gap forming portion 26 of the lead plate 15. The corresponding lead plate 15 is fixed to the lead plate reinforcing portion 16, and the lead plate reinforcing portion 16 is bent upward together with the gap forming portion 26 of the lead plate 15. That is, the lead plate 15 and the lead plate reinforcing portion 16 are fixed to the middle of the gap forming portion 26.

== Description of gyro vibrating piece ==
Next, the gyro vibrating piece will be described in detail with reference to the drawings. FIG. 3 is a diagram illustrating the operation of the drive arm. FIG. 4 is a diagram illustrating the relationship between the operation of the drive arm and the Coriolis force. FIG. 5 is a diagram illustrating the operation of the detection arm.

First, the configuration of the gyro vibrating piece will be described.
A gyro vibrating piece 10 that is an example of a piezoelectric vibrating piece and is used in the gyro sensor 100 shown in FIG. 1 is formed in a thin plate shape using crystal. The gyro vibrating piece 10 is a first driving arm portion and a first driving arm portion constituting a driving portion so as to operate in three modes known in the art, a driving mode, a detection mode, and a spurious mode. Drive arm 11A and second drive arm 11B, a detection arm 12 serving as a detection unit, an arm support unit 13 serving as an arm support unit, and a support plate 14 serving as a support unit.

  One end of the arm support portion 13 is connected to the center of the first drive arm 11A, the other end is connected to the center of the second drive arm 11B, and the center of the detection arm 12 is the arm support portion. 13 are connected to coincide with the center. The support plate 14 is a plate-like portion having a predetermined area including a connection point between the arm support portion 13 and the detection arm 12.

Next, the operation of the gyro vibrating piece will be described.
As shown in FIG. 3A, the first drive arm 11A is a plate-like portion having a predetermined length extending in the Y direction shown. The first drive arm 11 </ b> A responds to the rotation angular velocity in accordance with the rotation given with the Z direction shown in the figure as a rotation axis during vibration along the X direction shown in the figure. A Coriolis force corresponding to the size of is generated. The second drive arm 11B is a plate-like portion (not shown) having a predetermined length parallel to the first drive arm 11A, and generates a Coriolis force in the same manner as the first drive arm 11A.

  As shown in FIGS. 3A to 3C, the first drive arm 11A vibrates due to a bending operation with its center as an axis, and more specifically, the portion closer to the end portion is closer to the X direction. It vibrates by being deformed into a concavo-convex shape that is largely displaced along. The second drive arm 11B vibrates by a bending operation into a shape that is axisymmetrical to the concavo-convex shape that the first drive arm 11A deforms.

  As shown in FIG. 4, the first drive arm 11A is changed from the shape shown by the two-dot chain line to the shape shown by the solid line, and the second drive arm 11B is also shown by the two-dot chain line. When changing from the shape indicated by the solid line to the clockwise direction in the drawing, the Coriolis force is generated in the direction indicated by the arrows 19A and 19B in FIG. On the other hand, the first drive arm 11A is changed from the shape indicated by the solid line to the shape indicated by the two-dot chain line, and the second drive arm 11B is indicated by the two-dot chain line from the shape indicated by the solid line. When changing to the shape, if a clockwise rotation in the paper is applied, the Coriolis force is generated in the direction opposite to the arrows 19A and 19B in FIG.

  Similar to the first drive arm 11A and the second drive arm 11B, the detection arm 12 is a plate member having a predetermined length extending along the Y direction shown in the drawing. That is, the first drive arm 11A, the second drive arm 11B, and the detection arm 12 are parallel to each other. The detection arm 12 is transmitted from the first drive arm 11A and the second drive arm 11B through the arm support portion 13 so as to detect the Coriolis force acting on the first drive arm 11A and the second drive arm 11B. In response to the Coriolis force, vibration corresponding to the magnitude of the Coriolis force is performed.

  As shown in FIGS. 5A to 5C, the detection arm 12 is synchronized with the bending operation of the first drive arm 11A and the second drive arm 11B shown in FIGS. 3A to 3C. Thus, a bending operation of deforming into an approximately S shape and an inverted S shape is performed. The magnitude of the Coriolis force is obtained by detecting an electrical signal generated by the bending operation by the detection arm 12, and thereby the magnitude of the rotational angular velocity applied to the object is recognized.

According to the first embodiment described above, since the lead plate reinforcing portion 16 and the lead plate 15 protruding from the support substrate 18 are joined, the rigidity of the lead plate reinforcing portion 16 is in addition to the rigidity of the lead plate 15 alone. Is added. As a result, the rigidity of the joining portion, that is, the rising portion where the lead plate 15 is easily deformed, is apparently increased. Therefore, even when an impact is applied to the gyro vibrating piece 10 as an example of the piezoelectric vibrating piece, the gyro vibrating piece 10 is supported. The deformation of the lead plate 15 is less likely to occur. Therefore, it is difficult for the holding posture of the gyro vibrating piece 10 to change, and it is possible to provide the gyro sensor 100 that prevents the detection sensitivity of the gyro vibrating piece 10 from being lowered.
Further, since the lead plate reinforcing portion 16 is formed by projecting a part of the support substrate 18, the lead plate reinforcing portion 16 can be formed without using other materials, that is, without increasing the number of components. In addition, the gyro sensor 100 with improved characteristics can be provided at low cost.
(Second embodiment)

  As a second embodiment of the piezoelectric device according to the present invention, a gyro sensor using a gyro vibrating piece as a piezoelectric vibrating piece will be described with reference to the drawings. FIG. 6 is a plan view schematically showing the gyro sensor of the second embodiment. FIG. 7 shows an outline of the gyro sensor of the second embodiment, and is a cross-sectional view taken along the line BB of FIG.

  Since the configuration of the gyro sensor 100 and the gyro vibrating piece 10 in the second embodiment are the same as those in the first embodiment described above, a detailed description thereof will be omitted, and the lead that is a feature of the second embodiment. Details of the plate 35 and the lead plate reinforcing portion 36 will be described.

  According to FIGS. 6 and 7, the gyro sensor 100 is connected to the support substrate 39 fixed to the bottom surface 37 of the recess 40 of the package 40, the lead plate 35 connected to the projecting portion 36 of the support substrate 39, and the lead plate 35. The gyro vibrating piece 10 and the lid 41 fixed to the upper surface of the package 40 are configured.

  For example, the support substrate 39 formed of an insulator such as polyimide resin has a conductive pattern (not shown) formed on the surface thereof, and a window opening portion 38 formed by punching the center portion. A lead plate reinforcing portion 36 in which the support substrate 39 protrudes toward the center of the support substrate 39 is formed so as to protrude from the window opening portion 38. The lead plate reinforcing portion 36 is provided corresponding to the lead plate 35, and is bent obliquely upward near the base portion protruding from the support substrate 39.

  Six lead plates 35 of this example are provided, and nickel gold plating is applied to a copper thin plate having a thickness of 18 μm and a width of 30 to 100 μm as an example as in the first embodiment. The lead plate 35 is electrically joined in the vicinity of one end 42 using a conductive pattern in the lead plate reinforcing portion 36 and a conductive adhesive or solder. Further, the lead plate 35 is formed with a receiving portion 43 of the gyro vibrating piece 10 whose other end is bent so as to be substantially parallel to the support substrate 39. The receiving portions 43 formed on the six lead plates 35 are provided with the height matched so that the surface of the support substrate 39 and the gyro vibrating piece 10 are parallel to each other. An electrode (not shown) of the gyro vibrating piece 10 is connected to the receiving portion 43 by a conductive adhesive or a bonding material (not shown) such as a gold bump, and the electrical connection between the lead plate 35 and the electrode of the gyro vibrating piece 10 is performed. Continuity is taken.

  According to the second embodiment described above, in addition to the effects of the first embodiment described above, since the one end 42 of the lead plate 35 is on the surface of the lead plate reinforcing portion 36, the adjustment of the lead plate 35 in the height direction is performed. Can be easily performed. Accordingly, the heights of the receiving portions 43 of the plurality of lead plates 35 can be made uniform. Therefore, it is possible to easily realize the parallelism between the support substrate 39 and the gyro vibrating piece 10.

In the above-described embodiment, the configuration of the six lead plates has been described. However, the number of lead plates is not limited to this, and any number of configurations may be used as long as it is a required number.
In addition, the connection between the lead plate and the conductive pattern of the support substrate is made by joining the metal layer forming the conductive pattern and the lead plate with a conductive material, or by directly extending the metal layer forming the conductive pattern and the lead plate. Either of the configurations to be used may be used.
(Modification of lead plate reinforcement)

  Here, a modified example of the lead plate reinforcing portion will be described. 8A to 8C are plan views showing the shape of the lead plate reinforcing portion.

  As shown in FIG. 8A, the lead plate reinforcing portion 56 is formed by a portion 56A in which a part of the support substrate 59 protrudes along the side of the lead plate 55 and a portion 56B that intersects the protruding portion 56A. Has been. The lead plate 55 is bent obliquely upward (frontward in the figure) at the bent portion 57, and the lead plate reinforcing portion 56 is also bent obliquely upward at the bent portion 58 in the same manner as the lead plate 55. Both bent portions 57 and 58 are formed on the extension of the side 60 of the window opening portion of the support substrate 59. The lead plate 55 and the lead plate reinforcing portion 56 are joined at an overlapping portion.

  Further, as shown in FIG. 8B, the lead plate reinforcing portion 56 is formed in a shape in which a part of the support substrate 59 protrudes along both sides of the lead plate 55 and connects the tips. That is, a window opening portion is formed at the center of the overhanging portion. As described above, the lead plate 55 and the lead plate reinforcing portion 56 are bent obliquely upward at a bent portion 57 formed on the extension of the side 60 of the window opening portion of the support substrate 59. Further, the lead plate 55 and the lead plate reinforcing portion 56 are joined at an overlapping portion.

  Further, as shown in FIG. 8C, the lead plate reinforcing portion 56 is formed in a shape in which the width of the connecting portion with the support substrate 59 is wide and the width of the protruding tip portion is narrow. Note that the lead plate 55 and the lead plate reinforcing portion 56 are joined, and both are bent obliquely upward on the extension of the side 60 of the window opening portion of the support substrate 59.

In the above-described modification, the example in which the bending position of both is provided on the extension of the side of the window opening provided at the center of the support substrate 59 has been described. In other words, it may be performed at a place where the lead plate is away from the support substrate.
Further, the lead plate and the lead plate reinforcing portion are not joined, and the lead plate can be prevented from being deformed downward even in a contacted configuration.

According to the above-described modification of the reinforcing portion, the lead plate reinforcing portion 56 is joined to the lead plate 55, whereby the rigidity of the joined portion is increased. That is, apparently the rigidity of the lead plate 55 is increased, and even if an impact or the like is applied to the gyro vibrating piece, the lead plate 55 is hardly deformed.
(Third embodiment)

  A piezoelectric oscillator using the piezoelectric vibrating piece of the present invention will be described with reference to the drawings. FIG. 9 is a schematic front sectional view of the piezoelectric vibrator of the present invention.

  The piezoelectric oscillator 80 of the present invention includes a gyro vibrating piece 10 that is a crystal piece as an example of a piezoelectric oscillating piece, a plurality of lead plates 65 for holding the gyro vibrating piece 10, and a support substrate 69 that supports the plurality of lead plates 65. The semiconductor device 66 as an example of a circuit element having a function of driving at least the gyro vibrating piece 10, a package 70 for housing each of the above-described components, and a lid 71.

  Specifically, the support substrate 69 is fixed to the bottom surface of the recess of the package 70 made of ceramic or the like. The support substrate 69 is made of, for example, polyimide resin. A plurality of lead plates 65 extending from each direction toward the central portion are fixed to the upper surface of the support substrate 69 by a bonding material (not shown). The gyro vibrating piece 10 is joined to the plurality of lead plates 65 at one end with a joining material (not shown) such as a conductive adhesive or a gold bump. Further, a lead plate reinforcing portion 68 in which a part of the support substrate 69 protrudes is joined to a gap-forming portion 67 having a rising shape formed by being bent obliquely upward toward the center portion of the package of the plurality of lead plates 65. Has been. The lead plate reinforcing portion 68 reinforces the strength of the lead plate 65 and increases the rigidity.

In the above description, the gyro vibrating piece made of a quartz piece is used as an example of the piezoelectric vibrating piece. However, the present invention is not limited to this. For example, a rectangular, tuning fork type, disc-like quartz vibrating piece, lithium tantalate (LiTaO ₃ ) A vibrating piece using other piezoelectric materials such as a vibrating piece may be used.

  According to the third embodiment described above, the lead plate reinforcing portion 68 is joined to the lead plate 65 that holds and connects the gyro vibrating piece 10, thereby increasing the rigidity of the lead plate 65 and impacting the gyro vibrating piece 10. Even if such is added, the deformation of the lead plate 65 hardly occurs. Therefore, it is difficult for the holding posture of the gyro vibrating piece 10 to change, and the reduction in the detection sensitivity of the gyro vibrating piece 10 caused by the change in parallelism between the gyro vibrating piece 10 and the bottom surface of the package 70 is prevented. It is possible to provide a piezoelectric oscillator that can perform the following.

  Note that the lead plate reinforcing portion may be provided in all regions in the longitudinal direction of the lead plate except for the connection portion with the support substrate and the connection portion with the piezoelectric vibrating piece.

  In the above description, the piezoelectric vibration piece is supported by a plurality of lead plates with respect to the support substrate. However, the present invention is not limited to this, and the piezoelectric vibration piece is supported by one lead plate with respect to the support substrate. It may be a structure.

The top view which shows the outline of the gyro sensor of 1st embodiment. AA sectional drawing of FIG. (A)-(c) is a top view which shows operation | movement of the drive arm of a gyro vibrating piece. The top view which shows the relationship between operation | movement of the drive arm of a gyro vibrating piece, and Coriolis force. (A)-(c) is a top view which shows operation | movement of the detection arm of a gyro vibrating piece. The top view which shows the outline of the gyro sensor of 2nd embodiment. BB sectional drawing of FIG. (A)-(c) is a top view which shows the modification of a lead board reinforcement part. The front sectional view of the piezoelectric vibrator of a third embodiment. The front sectional view showing a conventional piezoelectric device.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 ... Gyro vibrating piece as a piezoelectric vibrating piece, 11A ... 1st drive arm, 11b ... 2nd drive arm, 12 ... Detection arm, 13 ... Arm support part, 14 ... Support plate, 15 ... Lead plate, 16 ... Lead plate reinforcing portion, 17 ... bottom of recess, 18 ... support substrate, 20 ... package, 21 ... lid, 22 ... connecting portion, 23 ... receiving portion, 24 ... tip of lead plate reinforcing portion, 25 ... window opening, 26 ... Gap sensor, 27 ... center of support substrate, 66 ... semiconductor device as circuit element, 80 ... piezoelectric oscillator, 100 ... gyro sensor as piezoelectric device.

Claims (8)

A piezoelectric vibrating piece;
A support substrate;
A lead plate for connecting the piezoelectric vibrating piece and the support substrate to make both conductive and supporting the piezoelectric vibrating piece in a state of being separated from the support substrate;
A piezoelectric device comprising: a lead plate reinforcing portion formed by extending a part of the support substrate substantially along the lead plate and joined to the lead plate. The piezoelectric device according to claim 1.
The lead plate reinforcing portion protrudes toward a substantial center of the support substrate. The piezoelectric device according to claim 1.
The tip of the lead plate reinforcing portion is formed between the lead plate and the connecting portion between the piezoelectric vibrating piece and the piezoelectric device. The piezoelectric device according to claim 1.
The piezoelectric device, wherein the lead plate separates the piezoelectric vibrating piece from the support substrate in a bent state. The piezoelectric device according to any one of claims 1 to 4,
The piezoelectric device, wherein the lead plate and the lead plate reinforcing portion are bent in a state where both are joined, and the piezoelectric vibrating piece is separated from the support substrate. The piezoelectric device according to claim 1.
The piezoelectric device, wherein the supporting substrate and the lead plate are connected on a surface of the bent lead plate reinforcing portion. The piezoelectric device according to any one of claims 1 to 6,
A piezoelectric device, wherein the piezoelectric vibrating piece is a gyro vibrating piece used in a gyro sensor for detecting a rotational angular velocity. A piezoelectric device according to any one of claims 1 to 7,
And a circuit element having a function of driving at least the piezoelectric vibrating piece.

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