JP2011075415A - Piezoelectric oscillation device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a piezoelectric oscillation device with excellent vibration-proof and shock-resistant performance. <P>SOLUTION: The piezoelectric oscillation device 2 incorporated in a gyro sensor device 1 includes a base 20, driving arms 21a and 21b extending in a +Y direction across it, and a detecting arms 22a and 22b extending in a -Y direction. In addition, supporting arms 23a and 23b connected with linear parts 25a and 25b via curved parts 24a and 24b are provided in ±X directions across the base 20. The linear parts 25a and 25b are connected to a fixing part 27 to be fixed to a sensor fixing part of a holding part. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a device including a vibration detecting piezoelectric element, and more particularly to a gyro sensor and the like for detecting an angular velocity of an object.

  Conventionally, a piezoelectric vibration device including a piezoelectric element has been used for the purpose of detecting minute vibrations. As such a piezoelectric vibration device, various devices such as an ultrasonic sensor, a pressure sensor, and a gyro sensor (angular velocity sensor) exist. Among these, for example, a gyro sensor detects an angular velocity of an object, and vibration generated due to Coriolis force generated when rotation is applied to a vibrating mass body is transmitted via a piezoelectric element. By detecting, rotation (operation) in each direction can be detected and measured.

  In recent years, piezoelectric vibrating devices such as gyro sensors have been reduced in size and thickness, and those using piezoelectric thin films obtained by thin film processing or thin film formation have been proposed or already put into practical use. However, such a small and thin piezoelectric vibration device is generally easily affected by vibrations and impacts from the outside of the device or system in which the piezoelectric vibration device is mounted because the piezoelectric thin film itself is extremely thin. There is a tendency that the angular velocity is likely to be erroneously detected due to noise caused by the noise.

  Thus, Patent Documents 1 and 2 describe examples in which a suspension mechanism is additionally provided in the piezoelectric vibration element of the gyro sensor to attempt to improve the vibration resistance and shock resistance performance of the gyro sensor.

JP 2005-106481 A JP-A-2005-308683

  However, in order to manufacture the gyro sensor described in Patent Document 1, as a suspension mechanism, a bendable bridge provided at the opening of the central base portion where the vibration arm for detection is extended is attached to the element body itself of the gyro sensor. Since it is required to be attached and the accuracy required for the attachment is extremely high due to its structure, its manufacture is not easy. In addition, if the mounting accuracy of the suspension mechanism is not sufficiently high, it is extremely difficult to securely hold and fix the vibration node (vibration stationary point) of the vibration arm for detection. Since it is inevitably generated, the gyro sensor still has insufficient vibration and shock resistance.

  Further, in the gyro sensor provided with the piezoelectric vibrating element described in Patent Document 2, the piezoelectric vibrating piece including the detection vibrating arm is placed on the storage container from both sides (both sides along the XY plane) via the lead member. Although connected and fixed, this structure is intended to reduce noise that may be generated from the Z-axis vibration component, and the piezoelectric vibrating piece is “hard” in the angular velocity detection direction (around the Z-axis). ”(Rigid) state, that is, it is fixed with respect to the rotation detection direction (X direction or Y direction perpendicular to the Z axis). There is a problem that noise is generated due to the influence of the applied external vibration, and as a result, the vibration resistance and impact resistance performance of the gyro sensor is lowered.

  By the way, in recent years, gyro sensors have been widely installed in small electronic devices such as car navigation systems, digital (video) cameras, game machine controllers, mobile phones, and the like. Further miniaturization of the device itself is being attempted. As described above, when the gyro sensor itself (sensor element) is further reduced in size, the amplitude of the detection vibration is further reduced, and as a result, the detection signal is naturally further reduced, so that it is applied to the gyro sensor. The influence of noise due to external vibration becomes relatively large, and it may be difficult to obtain a desired sufficient sensitivity for the gyro sensor. In this respect as well, there is an urgent need to further improve the vibration and shock resistance performance of the gyro sensor.

  Accordingly, the present invention has been made in view of the above circumstances, and an object of the present invention is to provide a piezoelectric vibration device having vibration resistance and anti-impact performance superior to those of the prior art.

  In order to solve the above problems, a piezoelectric vibration device according to the present invention includes a sensor unit including a piezoelectric element on a semiconductor substrate, a fixing unit holding the sensor unit, a bending unit, and the sensor via the bending unit. And a plurality of support arm portions that connect the portion and the fixed portion.

  According to this configuration, the sensor unit of the piezoelectric vibration device can be formed as a thin film type, and when the sensor unit detects a minute vibration, an impact or vibration from the outside in the detection direction is fixed. Even if it is applied to the sensor, the external vibration is suppressed, absorbed, reduced, canceled, etc. by the curved part of the support arm part (however, the action is not limited to this), and the transmission / propagation to the sensor part is suppressed. Or, it can be said that “damping effect” can be obtained. In addition, the curved portion of the support arm portion has a higher effect of mitigating external vibration than other shapes (for example, L-shape, etc.), and itself has excellent impact resistance. Since the transmission of external vibration to the part is suppressed or prevented, the strain energy of the sensor part can be reduced to reduce the so-called “temperature drift effect”, thereby improving the operational stability of the piezoelectric vibration device. Is also possible.

  Specifically, a configuration in which the sensor unit has a vibrating arm composed of a driving arm and a detection arm and a base that supports the vibrating arm and to which the supporting arm unit is connected can be exemplified. A configuration in which the arm and the detection arm extend in directions opposite to each other with the base interposed therebetween may be mentioned. In such a configuration, since the support arm is connected to the base of the sensor unit, when external vibration is applied from the outside of the piezoelectric vibration device through the fixed unit, the external vibration is transmitted to the base by the support arm. Is suppressed, and the influence of external vibration on the vibrating arm composed of the drive arm and the detection arm can be reliably prevented.

  In the piezoelectric vibration device according to the present invention, since the support arm portion includes the curved portion, the effective length of the support arm portion can be extended as compared with the case where there is no curved portion. Depending on the case, the resonance frequency of the entire mass body (system as a whole) to which the support arm portion is connected (the same applies hereinafter) is reduced, so that the transmission rate of external vibration in the drive frequency region of the sensor portion is reduced. You can also. That is, from this point of view, it can be said that it is effective that the support arm portion is formed so that the resonance frequency is lower than that in the case where there is no curved portion.

  Moreover, the structure which a support arm part has a curved part and a linear part (more specifically, a linear part connected with a curved part and extending linearly) is mentioned. In this way, by arbitrarily combining the bending portion and the linear portion, the supporting arm portion can be formed in a desired and arbitrary shape (designed) while providing the bending portion in the supporting arm portion. It becomes possible to improve the workability, versatility, and structural stability of the entire piezoelectric vibration device in which the portion and the fixed portion are connected by the support arm portion.

  Furthermore, you may comprise so that a support arm part may contain the part by which the some bending part was provided in succession. In this case, the plurality of curved portions may be adjacent or closely adjacent to each other, or may be provided intermittently and continuously. According to this configuration, the effective length of the support arm portion can be further extended by having a plurality of curved portions, thereby further reducing the resonance frequency of the support arm portion, and vibration from the outside in the vibration detection direction. On the other hand, a higher attenuation effect can be realized, and the above-described temperature drift effect can be further reduced.

  Furthermore, it is preferable that the fixing portion surrounds at least a part of the sensor portion. If constituted in this way, part or all of the sensor part is protected by the fixing part due to its structure, so that the structural strength of the piezoelectric vibration device is improved and resistance to vibration and impact from the outside can be further increased. In addition, since the fixing portion can be disposed at a desired position around the sensor portion, it is possible to improve the shape design tolerance of the entire piezoelectric vibration device and the degree of freedom in assembly.

  Furthermore, when the support arm portion has a straight portion, it is useful to configure the straight portion so as to extend along the vibrating arm of the sensor portion. In such a configuration, it becomes easy to adjust the gap between the sensor unit and the support arm unit to an appropriate state, and in particular, the sensor unit and the support arm unit can be easily brought close to each other. , And mechanical strength (rigidity) can be improved. In addition, when an impact in the angular velocity detection direction (Z axis) or the like is applied to the linear portion, an effect of further mitigating the impact on the piezoelectric vibration device can be expected.

  According to the piezoelectric vibration device of the present invention, since the support arm having the curved portion is provided, even if the sensor portion of the piezoelectric vibration device is formed of a thin film, an impact is applied from the outside applied when the sensor portion detects minute vibrations. And vibration can be effectively suppressed or prevented from being transmitted / propagated to the sensor part by reducing it at the curved part of the supporting arm part, thereby significantly improving the vibration / impact resistance performance. Can be improved.

It is a perspective view which shows the structure of the gyro sensor apparatus which concerns on 1st Embodiment. It is a top view which shows the structure of the gyro sensor element which concerns on 1st Embodiment. It is a perspective view which shows the operation state of the gyro sensor element which concerns on 1st Embodiment. It is a perspective view which shows the operation state of the gyro sensor element which concerns on 1st Embodiment. It is a top view which shows the structure of the gyro sensor element which concerns on 2nd Embodiment. It is a top view which shows the structure of the gyro sensor element which concerns on 3rd Embodiment. It is a top view which shows the structure of the gyro sensor element which concerns on 4th Embodiment. It is a top view which shows the structure of the gyro sensor element which concerns on 5th Embodiment. It is a top view which shows the structure of the gyro sensor element which concerns on 6th Embodiment. It is sectional drawing which shows the structure of the ultrasonic sensor element which concerns on 6th Embodiment. It is a top view which shows the modification of the gyro sensor element which concerns on 6th Embodiment.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In the drawings, the same elements are denoted by the same reference numerals, and redundant description is omitted. Further, the positional relationship such as up, down, left and right is based on the positional relationship shown in the drawings unless otherwise specified. Furthermore, the dimensional ratios in the drawings are not limited to the illustrated ratios. The following embodiments are examples for explaining the present invention, and are not intended to limit the present invention only to the embodiments. Further, the present invention can be variously modified without departing from the gist thereof.

<First Embodiment>
FIG. 1 is a perspective view schematically showing an internal configuration of a gyro sensor device 1 according to a first embodiment of a piezoelectric vibration device according to the present invention. In this gyro sensor device 1 (piezoelectric vibration device), for example, indentations 41 and 42 provided with steps (in a step shape) are formed inside a case 4 having a box shape, a frame shape, or the like. The depressions 41 and 42 define internal spaces G1 and G2, respectively.

  An integrated circuit element support surface 43 is provided on the bottom surface of the deeper depression 41 of these depressions 41 and 42, and the integrated circuit element 3 is disposed thereon. Further, an annular holding portion support surface 44 is provided around the shallower recess 42, and the holding portion 5 is fixed thereon.

  The holding portion 5 includes a flat frame-shaped base portion 5a that is in contact with the holding portion support surface 44, and an inclined portion 5b that is bent and extends upward (in the drawing + Z-axis direction) from the base portion 5a toward the internal space G2. And a sensor fixing portion 5c that is bent again in a plane parallel to the integrated circuit element support surface 43 and the holding portion support surface 44. The gyro sensor element 2 is fixed to the sensor fixing portion 5c so as to be positioned in the same plane as the sensor fixing portion 5c or parallel to the sensor fixing portion 5c, and the internal space. Held in G2.

  The integrated circuit 3 transmits drive signals to a plurality of piezoelectric elements provided on each drive arm 21a and 21b of the gyro sensor element 2 described later, and is provided on each detection arm 22a and 22b of the gyro sensor element 2 described later. In addition, the detection signals output from the plurality of piezoelectric elements are received. The case 4 includes, for example, one formed by laminating a plurality of ceramic thin plates. Usually, when the gyro sensor device 1 is in use, a lid (not shown) that covers an open portion on the internal space G2. )).

  FIG. 2 is a plan view (top view) showing an example of the configuration of the gyro sensor element 2. The gyro sensor element 2 includes a base 20 that is located in the center and forms a rectangle (rectangle) in plan view, a pair of drive arms 21a and 21b that extend in one direction (+ Y direction in FIG. 2) across the base 20, and A pair of detection arms 22a and 22b extending on the side opposite to the drive arm (in the -Y direction in FIG. 2) is provided. Further, of the rectangular shape of the base 20 having the drive arm and the detection arm, a curved portion sandwiching the base 20 on the opposite side (± X direction in FIG. 2) different from the side where the drive arm and the detection arm are opposed to each other. A pair of support arms 23a and 23b are provided through 24a and 24b to the straight portions 25a and 25b, respectively, and these straight portions 25a and 25b are connected to the sensor fixing portion 5c of the holding portion 5 described above. It is connected to a fixed part 27 to be fixed.

  As shown in the figure, each of the pair of drive arms 21 a and 21 b, detection arms 22 a and 22 b, and support arms 23 a and 23 b is installed symmetrically with respect to the base 20. In this specification, the “left / right” direction refers to the ± X direction shown in the drawing, that is, a virtual vibration stationary point α (see FIG. 2) determined in consideration of the position of the center of gravity of the gyro sensor element 2. In addition, a direction (± X) orthogonal to a virtual center line β extending in parallel along the extending direction of each of the straight portions 25a and 25b of the drive arms 21a and 21b, the detection arms 22a and 22b, and the support arms 23a and 23b. Direction). Further, “left-right symmetry” is used for the sake of convenience to indicate left-right symmetry on the paper surface, and indicates line symmetry with the center line β as the symmetry axis. Furthermore, in the present embodiment, the horizontal tuning fork type is exemplified as the gyro sensor element 2, but the “tuning fork” in this case is a part (element) constituting the gyro sensor element 2. The part which consists of the base 20, the drive arms 21a and 21b, and the detection arms 22a and 22b is shown.

  In the present embodiment, the gyro sensor element 2 including the base 20, the drive arms 21a and 21b, the detection arms 22a and 22b, the support arms 23a and 23b, and the fixing portion 27 is made of a common material (for example, silicon). It is possible to form a batch by patterning a general wafer (silicon wafer or the like). Therefore, the gyro sensor element 2 according to the present invention includes the support member and the fixing member as compared with the case where a separate support member is attached to the tuning fork portion after the tuning fork portion is formed as in the prior art. By forming them in a lump, not only the man-hours in the manufacturing process are greatly reduced, but also the support arms 23a and 23b corresponding to the vibration stationary point α determined in advance in the design stage can be attached with high accuracy. It becomes possible.

  In particular, in the manufacture of the gyro sensor element 2 according to the present invention, even if a tuning fork having a complicated shape that is extremely difficult or impossible to accurately mount the support member with the conventional configuration, structural calculation by simulation or the like is performed in advance. Based on the results, it is possible to simply cope with the change of the patterning design of the wafer, and it is possible to reliably manufacture the gyro sensor element 2 having various shapes according to various use conditions.

  Further, as shown in FIG. 2, the base portion 20 is supported from the side surface direction (± X direction in the drawing) by a pair of support arms 23a and 23b provided symmetrically with respect to the base portion 20, thereby causing an internal space G2. As a result, the drive arms 21a and 21b and the detection arms 22a and 22b extending in the surface direction of the base 20 are also held in the internal space G2.

  Here, the pair of drive arms 21a and 21b extend in the + Y direction so as to be symmetrical and away from the base 20 on a plane including the base 20, the detection arms 22a and 22b, and the support arms 23a and 23b. The pair of detection arms 22a and 22b extend in the -Y direction so as to be symmetrical and away from the base 20 on a plane including the base 20, the drive arms 21a and 21b, and the support arms 23a and 23b. In this case, when the lengths of the drive arms 21a and 21b and the detection arms 22a and 22b (the length along the Y direction starting from the connection portion with the base 20) are equal to each other, the detection arm 22a , 22b (length along the X direction) is preferably larger (wider) than the width of the drive arms 21a, 21b.

  If comprised in this way, it will suppress that the tuning fork itself vibrates due to the vibration etc. to the X-axis direction of the drive arms 21a and 21b which generate | occur | produce at the time of the detection of Coriolis force propagating to the detection arms 22a and 22b. This makes it easier to effectively prevent the noise signal from being erroneously detected in the detection of the Coriolis force in the detection arms 22a and 22b. Therefore, from the viewpoint of further improving the angular velocity detection accuracy of the gyro sensor element 2, the width of the drive arms 21a and 21b can be made as narrow as possible to form the vibration piezoelectric element, and the width of the detection arms 22a and 22b is Taking the width of the base 20 into consideration, it is possible to make it as wide as possible. Further, it is more preferable that the detection piezoelectric elements formed on the detection arms 22a and 22b be wide as long as they do not exceed the width of the detection arm (22a or 22b).

  Further, a so-called root portion of the drive arms 21a and 21b (portion close to the connection portion with the base 20) is a pair of vibrations arranged symmetrically with respect to the extending direction of the drive arms 21a and 21b, respectively. Piezoelectric elements 26a and 26b and a pair of vibrating piezoelectric elements 26c and 26d are provided. The pair of piezoelectric elements 26a and 26b and the pair of piezoelectric elements 26c and 26d are configured so that the drive arms 21a and 21b are respectively connected to the base 20, the drive arms 21a and 21b, the detection arms 22a and 22b, and the support arms 23a and 23b. Is to vibrate in the X-axis direction along the plane including the.

  On the other hand, detection piezoelectric elements 26e and 26g are provided on one surface (surface) of a so-called root portion of the detection arms 22a and 22b (portion close to the connection portion with the base 20), respectively. These detection piezoelectric elements 26e and 26g are for detecting the vibration when the detection arms 22a and 22b vibrate in the Z-axis direction. Further, on the other surface (back surface) of each detection arm 22a, 22b, further detection piezoelectric elements 26f, 26h may be installed at positions corresponding to the detection piezoelectric elements 26e, 26g. It is possible to further increase the detection sensitivity and accuracy of the angular velocity by detecting vibration generated due to one Coriolis force using the piezoelectric elements 26e and 26f and the pair of detection piezoelectric elements 26g and 26h. It is.

  3A and 3B are perspective views schematically showing a state in which the gyro sensor element 2 is operating, and are also diagrams showing the principle of detection of angular velocity by the gyro sensor element 2. FIG. As shown in FIG. 3A, the gyro sensor element 2 initially expands / contracts the pair of vibration piezoelectric elements 26a and 26b in opposite phases by a control signal from the integrated circuit element 3, and the vibration piezoelectric element 26c, 26d is also expanded and contracted in the opposite phase to vibrate the driving arms 21a and 21b in the X-axis direction (the direction indicated by the arrow S1 in the drawing). At this time, the driving piezoelectric elements 26a and 26d are expanded and contracted in the same phase and synchronously, and the piezoelectric elements 26b and 26c are expanded and contracted in the same phase and synchronously, so that the driving arms 21a and 21b are mutually in the same cycle. Vibrates to repeat approach and separation.

  When the object on which the gyro sensor device 1 is mounted performs a rotational movement with the Y axis direction as the rotation axis during the vibration of the drive arms 21a and 21b, as shown in FIG. 3B, the drive arms 21a and 21b are moved to the Coriolis. A force acts, and the driving arms 21a and 21b generate detection vibrations in the opposite phase in the Z-axis direction (the direction indicated by the arrow S2 in the drawing). When the vibration caused by the Coriolis force acting on the drive arms 21a and 21b is transmitted to the base 20, the detection arms 22a and 22b connected to the base 20 are respectively connected to the drive arms 21a and 21b. Thus, vibrations occur in the opposite direction (the direction indicated by the arrow S3 in the figure) in the Z-axis direction, and the angular velocity is detected by detecting the displacement in the Z-axis direction of these detection arms 22a and 22b.

  Further, as described above, the gyro sensor element 2 has the pair of support arms 23a and 23b including the curved portion 24a and the straight portion 25a, and the curved portion 24b and the straight portion 25b, and the support arms 23a and 23b Since the base 20 is carried from the left and right sides, it is held in the internal space G2 in the gyro sensor device 1 (see FIG. 2). Here, in order to improve the vibration proof performance of the gyro sensor element 2, the connection position between the curved portions 24 a and 24 b of the support arms 23 a and 23 b and the base portion 20 is centered on the vibration stationary point α of the gyro sensor 2. It is preferable that the position is symmetrical with respect to the axis. In this configuration, as described above, in order to increase the detection sensitivity of the gyro sensor element 2, when the widths of the detection arms 22a and 22b are made larger than the widths of the drive arms 21a and 21b, the vibration rest point α is set to the center line β. Since it moves (displaces) in the -Y direction above, it is preferable that the connection positions of the curved portions 24a, 24b of the support arms 23a, 23b and the base 20 also move (displace) in the -Y direction.

  Further, the curved portions 24a and 24b of the support arms 23a and 23b have a linear shape extending in the direction away from the base 20 along the X axis in the vicinity of the connection portion with the base 20, and then the detection arms 22a and 22b. In the extending direction, the U-shaped curve is bent (bent) at a predetermined curvature of approximately 180 degrees, and further beyond that, the linear portion is again bent (bent) at a predetermined curvature of approximately 90 degrees in the opposite direction. 25 (see FIG. 2). According to the knowledge of the present inventor, in such bending portions 24a and 24b, in order for the gyro sensor element 2 to exhibit stable vibration resistance, the first bending of 180 degrees and the second bending of 90 degrees. It is desirable that the curvature of curvature (degree; so-called “R”) is the same or substantially the same. The straight portions 25a and 25b extending from the bending portions 24a and 24b are parallel to the extending direction of the detection arms 22a and 22b and extend close to the detection arms 22a and 22b, respectively. Thus, the total length of the support arms 23 a and 23 b including the curved portions 24 a and 24 b is longer than the total length of the detection rods 22 a and 22 b, and is finally connected to the fixed portion 27.

  In addition, since the tuning fork in the gyro sensor element 2 is supported from the left and right by the pair of support arms 23a and 23b, when an external impact is applied around the Z axis, the tuning fork is The tuning fork itself is prevented from rotating compared to the case where it is supported by the upper surface. Further, since the support arms 23a and 23b have the curved portions 24a and 24b, the gyro sensor element 2 is configured even when an external impact in the Z-axis direction (Coriolis force detection direction) is applied to the gyro sensor element 2. The “damping effect” that the external vibration is not propagated to the tuning fork, that is, the base 20, the drive arms 21a and 21b, and the detection arms 22a and 22b can be effectively expressed. The damping effect by having such curved portions 24 a and 24 b is also effective when an external impact in the X direction and / or Y direction is applied to the gyro sensor element 2.

  In addition, by having the curved portion 24, the effective length of the support arms 23a and 23b becomes longer than when the support arms 23a and 23b are not provided, and the resonance frequency of the support arms 23a and 23b is significantly increased. Since it decreases, it becomes possible to realize a higher vibration damping effect (reduction of vibration transmissibility at the driving frequency of the tuning fork) with respect to the vibration in the detection direction of the Coriolis force, and as a result, the stress relaxation effect becomes higher. Impact resistance is also improved. Furthermore, since the support arms 23a and 23b have the curved portions 24a and 24b, the distortion energy of the gyro sensor element 2 main body that may be generated due to external vibration or impact can be reduced significantly. Thereby, according to the gyro sensor element 2, it is also possible to prevent the “temperature drift effect” in which such strain energy is converted into thermal energy and the temperature of the element body rises.

  Furthermore, when a shock in the Z-axis direction is applied to the linear portion 25a or 25b of the support arms 23a and 23b, the moment of force applied to the entire gyro sensor element 2 is from the center line β to the linear portions of the support arms 23a and 23b. Since the distance to 25a, 25b is shorter, the linear portions 25a, 25b of the support arms 23a, 23b extend close to the detection arms 22a, 22b in the same plane as the detection arms 22a, 22b. Furthermore, excellent vibration and shock resistance effects can be expected. Thus, for example, in order to bring the straight portion 25 of the support arm 23 closer to the detection arm 22, the shapes of the curved portions 24a and 24b in the present embodiment are most preferably U-shaped.

  Furthermore, since the support arms 23a and 23b have the curved portions 24a and 24b, the lengths of the linear portions of the curved portions 24a and 24b and the curvature (degree of bending) of the curved portions are appropriately adjusted. As a result, it is possible to increase the mechanical rigidity of the entire gyro sensor element 2 while reducing the installation area so that the straight portions 25a, 25b and the detection arms 22a, 22b are close to each other. is there. Further, from the viewpoint of further reducing the resonance frequency of the support arms 23a and 23b, the width of the support arms 23a and 23b is preferably made as small (thin) as possible so that the tuning fork that is the support target can be safely supported. Furthermore, the widths of the support arms 23a and 23b can be partially increased or decreased in order to enhance the vibration and shock resistance effects as the shape of the tuning fork changes.

  The fixing portion 27 to which the support arms 23a and 23b are connected is fixed to the end portion of the sensor fixing portion 5c. Here, when the support part 5 including the sensor fixing part 5c is made of an elastic body such as a metal spring having elasticity, for example, the support part 5 can be appropriately bent in the Coriolis force detection direction (Z-axis direction). As a result, the vibration resistance and shock resistance performance can be further improved, and the angular velocity detection sensitivity can be further increased. The fixing unit 27 is connected to a power source (not shown) that supplies power to the driving and detection piezoelectric elements, and is mounted on the support arms 23a and 23b from, for example, electrode pads provided on the fixing unit 27. Since it is possible to supply power to the drive arms 21a and 21b and the detection arms 22a and 22b through the conductors such as the arranged wiring lines, it is not necessary to provide a separate wiring for the piezoelectric element in this case. Inconveniences such as erroneous detection of vibration that may occur due to contact between the wiring and the driving arms 21a and 21b and the detection arms 22a and 22b can be suppressed, and durability and reliability of the gyro sensor element 2 can be improved.

  Moreover, since the tuning fork structure, the support portion 23, and the fixing portion 27 of the gyro sensor element 2 are integrally formed of, for example, silicon, each connection site in the gyro sensor element 2 is not required to go through a complicated assembly process. Naturally, the gyro sensor element 2 can be mounted (processed) with extremely high precision and the rigidity of the gyro sensor element 2 can be sufficiently increased, so that the vibration resistance and shock resistance performance of the gyro sensor 2 can be greatly improved greatly. Can do.

Second Embodiment
FIG. 4 is a plan view (top view) showing an example of the configuration of the gyro sensor element 30 according to the second embodiment of the piezoelectric vibrating device according to the present invention. The gyro sensor element 30 has a rectangular (rectangular) shape having a fixed side 272a on the lower side, a fixed side 272b on the right side, a fixed side 272c on the same side, and a fixed side 272d on the left side instead of the fixed part 27. A fixed portion 272 that is a frame body is provided, and the base portion 20, the drive arms 21a and 21b, the detection arms 22a and 22b, and the support arms 23a and 23b are all surrounded by the fixed portion 272 in the same plane. Except for this, the configuration is the same as that of the gyro sensor element 2 described above. Therefore, in FIG. 4, the same reference numerals are given to members common to the gyro sensor element 2, and the description thereof will be omitted here in order to avoid redundant description (the same applies to FIGS. 5 to 8). .)

  As in the first embodiment, the gyro sensor element 30 is made of a common material (for example, silicon), and can be formed in a lump by patterning a general wafer (silicon wafer or the like). Here, the fixing portion 272 holds the support arms 23a and 23b, and at the same time, protects the internal base portion 20, the drive arms 21a and 21b, the detection arms 22a and 22b, the support arms 2323a and 23b, and the like from four directions. It has the effect of increasing the resistance to external vibrations and impacts.

  The portion of the fixing portion 272 to be fixed to the end portion of the sensor holding portion 5c is not limited to the fixing side 272a corresponding to the fixing portion 27 in the gyro sensor element 2, but the fixing side 272b on the right side of the figure, Either the fixed side 272c or the fixed side 272d on the left side may be used. In particular, the fixed sides 272b and 272d may be fixedly connected to the sensor holding portion 5c for the purpose of changing the shape of the case 4 to a desired shape.

<Third Embodiment>
FIG. 5 is a plan view (top view) showing an example of the configuration of the gyro sensor element 40 according to the third embodiment of the piezoelectric vibrating device according to the present invention. The gyro sensor element 40 is the same as the gyro sensor element 2 described above except that the support arms 23a and 23b having the curved portions 24a and 24b are replaced with (double) curved portions 243a and 243b having two curved portions. It is composed of.

  The curved portions 243a and 243b of the gyro sensor element 40 have a linear shape extending in the direction away from the base 20 along the X axis in the vicinity of the connection portion with the base 20, and then a detection arm (not shown) (Same as 22a, 22b) is bent (bent) approximately 180 degrees with a predetermined curvature, and then is bent approximately 180 degrees in the opposite direction, and further in the opposite direction (the same direction as the first curve). ) And is further bent approximately 90 degrees in the opposite direction (the same direction as the second curve) and then connected to the straight portion 253, and the support arms 233 a and 233 b are connected to the fixing portion 273. Connected with. At this time, in order to express more stable vibration resistance performance, it is desirable that the curvatures of the first to fourth curves are the same or substantially the same.

  Similarly to the first embodiment, the gyro sensor element 40 configured as described above can be collectively formed by patterning a common material. Further, by having the double curved portions 243a and 243b, the gyro sensor element 40 obtains a higher damping effect when external vibration in the Z-axis direction (Coriolis force detection direction) is applied. be able to. Further, since the effective lengths of the support arms 233a and 233b are further increased by having the double curved portions 243a and 23b, the Coriolis force detection direction is further reduced by further reducing the resonance frequency of the support arms 233a and 233b. It is possible to obtain a higher damping effect against the vibration of the material, thereby further enhancing the stress relaxation effect and further improving the impact resistance performance, and further reducing the “temperature drift effect”. Is possible.

  Further, since the double curved portions 243a and 243b are provided, the lengths of the straight portions 253a and 253b of the support arms 233a and 233b adjacent to the detection arms (similar to the detection arms 22a and 22b) are different from those of the first embodiment. However, the combination of the number of times of bending at the bending portions 243a and 243b and the length of the straight portions 253a and 253b gives the best vibration and shock resistance performance in consideration of conditions such as the shape and mass of the tuning fork. It can be appropriately selected by structural calculation by computer simulation or the like in advance. Further, as described above, the gyro sensor element 40 of the present embodiment can also be manufactured by batch formation by patterning a wafer, so that it can be easily manufactured with sufficiently high productivity.

<Fourth embodiment>
FIG. 6 is a plan view (top view) showing an example of the configuration of the gyro sensor 50 according to the fourth embodiment of the piezoelectric vibrating device according to the present invention. The gyro sensor 50 is configured in the same manner as the gyro sensor element 2 except that the gyro sensor 50 includes support arms 234a and 234b connected to separate fixing portions 274a and 274b instead of the support arms 23a and 23b. It is.

  The combination of the support arms 234a and 234b and the separate fixing portions 274a and 274b in the gyro sensor element 50 further improves the design freedom of the gyro sensor device 1. For example, the gyro sensor element 50 may change the position and shape of the sensor holding portion 5c in the internal space of the case 4 in order to change the shape of the case 4 according to the shape of a desired installation location. For example, this can be dealt with by adjusting the curved portion and the straight portion of one of the support arms 234a, and the respective curved portions and straight portions of both the support arms 234a and 234b may be appropriately adjusted. Such adjustment of the shape of the support arm can be appropriately selected by structural calculation by computer simulation or the like in advance so as to obtain the best vibration and shock resistance performance in consideration of conditions such as the shape and mass of the tuning fork. . Further, as described above, the gyro sensor element 50 of this embodiment can also be manufactured by batch formation by wafer patterning, and can be easily manufactured with sufficiently high productivity.

<Fifth Embodiment>
FIG. 7 is a plan view (top view) showing an example of the configuration of a gyro sensor 60 according to a fifth embodiment of the piezoelectric vibrating device according to the present invention. In addition to the support arms 235a and 235b provided on the detection arms 22a and 22b (not shown) side of the gyro sensor element 2, the gyro sensor 60 also supports the drive arms 21a and 21b (not shown). 235c and 235d are provided and are configured in the same manner as the gyro sensor element 2 except that they are connected to the fixing portions 275a and 275b, respectively.

  According to the gyro sensor 60 having such a configuration, the tuning fork is connected to the support arms 235a, 235b, 235c, and 235d on the side surface, and after bending, the support arms 235a, 235b, 235c, and 235d are fixed from both the upper and lower directions in the drawing. As a result, it is possible to prevent a tilt or deviation in the Z-axis direction that occurs in the tuning fork. Note that the drive arm (not shown but similar to the drive arms 21a and 21b) vibrates in the lateral direction (X-axis direction) by the piezoelectric element, and thus may come into contact with the linear portions 255c and 255d of the support arms 235c and 235d. In such a case, the degree of bending of the bending portions 245c and 245d may be adjusted as appropriate.

<Sixth Embodiment>
FIG. 8 is a plan view (top view) showing an example of the configuration of the gyro sensor 70 according to the sixth embodiment of the piezoelectric vibrating device according to the present invention. In the gyro sensor 70, the support arms 236a and 236b extending from the base 20 extend in a direction (Y-axis direction) parallel to the extending direction of the detection arms (not shown but similar to the detection arms 22a and 22b) by bending. Without extending the base portion 20 in the left-right direction (X-axis direction) and being connected to separate fixing portions 276a and 276b, respectively. is there.

  Such a configuration of the gyro sensor 60 is particularly effective when used not only for a gyro sensor but also for an ultrasonic sensor using a piezoelectric element. Here, FIG. 9 is a cross-sectional view schematically showing an example of the configuration of an ultrasonic sensor element to which the configuration of the gyro sensor 60 can be applied. As shown in FIG. 9, the ultrasonic sensor 6 electrically causes vibration of the thin film 160 due to ultrasonic waves by a piezoelectric element 161 (for example, an element having a laminated structure in which lead zirconate titanate (PZT) is sandwiched between a pair of Pt). It is a detection device and does not require a plurality of drive arms 21a, 21b and detection arms 22a, 22b unlike the gyro sensor element 2 for measuring the angular velocity, and therefore has a simpler configuration than the gyro sensor element 2 or the like. In addition, the size and weight can be reduced, and the degree of freedom of installation is further increased.

  FIG. 10 also shows that the four support arms 237a, 237b, 237c, and 237d are fixed to the fixing portions 277a, 277b, 277c, and 237d, respectively, in order to further improve the vibration and shock resistance effects on the gyro sensor element 2 and the ultrasonic sensor 6. It is a top view which shows the structure of the modification of 6th Embodiment formed by connecting to 277d. In this modification, when the light-weight ultrasonic sensor element 6 is used, the linear portions of the support arms 237a, 237b, 237c, and 237d are held by holding the sensor elements by the four support arms 237a, 237b, 237c, and 237d. Even if it is extremely short, it is possible to obtain a sufficient vibration and impact resistance effect only by the presence of the curved portion. Therefore, the package of the ultrasonic sensor device including the support arms 237a, 237b, 237c, and 237d can be made smaller. It is possible to

  The present invention is not limited to each of the above-described embodiments. As described above, various modifications (for example, appropriate contents of each embodiment are possible without departing from the spirit of the present invention). Combination) is possible.

  DESCRIPTION OF SYMBOLS 1 ... Gyro sensor apparatus (piezoelectric vibration device), 2, 30, 40, 50, 60, 70 ... Gyro sensor element (piezoelectric vibration device), 3 ... Integrated circuit element, 4 ... Case, 5 ... Holding part, 5a ... Base Part, 5b ... inclined part, 5c ... sensor fixing part, 6 ... ultrasonic sensor (piezoelectric vibration device), 20 ... base part, 21, 213, 214, 215, 216, 217 ... drive arm, 22, 223, 224, 225 , 226, 227 ... detection arm, 23, 233, 234, 235, 236, 237 ... support arm, 24, 243, 244, 245, 246, 247 ... curved portion, 25, 253, 254, 255, 256, 257 ... Linear part, 26 ... Piezoelectric element, 27, 272, 273, 274, 275, 276, 277 ... Fixed part, 160 ... Thin film, 161 ... Piezoelectric element, 41, 42 ... Depression, 43 ... Collection Circuit element support surface, 44 ... holding part support surface, G1, G2 ... internal space, α ... vibration stationary point, β ... central axis, (in the reference numerals of each member, subscripts are added as necessary for convenience of explanation) “A”, “b”, etc. were omitted as appropriate).

Claims (8)

A sensor unit including a piezoelectric element on a semiconductor substrate;
A fixing part for holding the sensor part;
A support arm part including a bending part and connecting the sensor part and the fixing part via the bending part;
A piezoelectric vibration device having: The sensor unit includes a vibrating arm including a driving arm and a detection arm, and a base that supports the vibrating arm and is connected to the supporting arm unit.
The piezoelectric vibration device according to claim 1. The support arm portion is formed so that the resonance frequency is reduced as compared with the case where the bending portion is not provided.
The piezoelectric vibration device according to claim 1 or 2. The support arm portion has a curved portion and a straight portion.
The piezoelectric vibration device according to claim 1. The support arm portion has a portion in which a plurality of the curved portions are continuously provided.
The piezoelectric vibration device according to claim 1. The fixing portion surrounds at least a part of the sensor portion;
The piezoelectric vibration device according to claim 1. The linear portion of the support arm portion extends along the vibrating arm of the sensor portion;
The piezoelectric vibration device according to claim 2. The drive arm and the detection arm extend in opposite directions with the base interposed therebetween,
The piezoelectric vibration device according to claim 2.

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