JP2013113776A - Angular velocity sensor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an angular velocity sensor for reducing off-set drift resulting from undesired torque caused by disturbance vibrations by suppressing the influence of the disturbance vibrations from the outside.SOLUTION: The angular velocity sensor has a package 10 for housing an angular velocity detection element 11, and lead terminals 17 connected to the package 10. Each of the lead terminals 17 has a first end connected to the package 10, and a second end 13 for being connected to the outside, a plate-like extension part 16 having an extension surface extended in a predetermined extension direction is provided between the first end and the second end 13, and the extension surface of the lead terminal 17 includes a first shaft, and is perpendicular to a face perpendicular to a base part.

Description

The present invention relates to an angular velocity sensor formed by housing a vibrating angular velocity detection element in a package.

This angular velocity sensor is applied, for example, as an angular velocity sensor that is mounted on a car and applied to the car. As a configuration of this angular velocity sensor, a circuit board and an angular velocity detecting element are mounted in the package via an adhesive, and each part is electrically connected by a bonding wire and electrically connected to the angular velocity detecting element. It has a lead terminal. The package accommodates the angular velocity detecting element and the circuit board, and serves as a base that forms the main body of the angular velocity sensor.

In addition to automobiles, automatic navigation systems such as airplanes and ships are also used to measure the angular velocity of the aircraft when performing vehicle body control. Also in games and mobile phones, it is used as a sensor for sensing the movement of a device in an input method performed by converting the movement of the device into a signal.

This type of angular velocity sensor vibrates a drive part which is a vibrating body by an oscillation circuit, and when a rotational force is applied to the sensor from the outside, a force called Coriolis force is generated in a direction perpendicular to the vibrating part in the sensor. . The Coriolis force is detected as the displacement of the detection portion that is a vibrating body, the output signal detected by the circuit board is amplified, the output waveform is corrected, and the angular velocity is output. The angular velocity sensor includes a lead terminal for electrical connection with the outside.

Conventionally, as in Patent Document 1, an attachment structure has been proposed in which such an angular velocity sensor is mounted on a substrate via a lead terminal. In this lead terminal, a mounting member is disposed so as to surround the outer periphery of the package, and the outer peripheral end portion of the package is electrically and mechanically connected to the mounting substrate located at the periphery or the lower portion by the lead terminal. Is.

In Patent Document 1, there is a lead terminal for electrically connecting the angular velocity sensor and the outside, and an extension portion is provided at an intermediate portion thereof. Due to the spring property of the lead terminal, it can vibrate in a direction orthogonal to the direction in which the extension extends, and this vibration direction is a direction along the direction of the detected vibration of the vibrating body in the package, that is, the extension. Vibrates substantially in the same direction as the detected vibration of the vibrating body.

In Patent Document 1, noise resistance / vibration resistance is a very important factor for angular velocity sensors in order to detect angular velocity without malfunction. For example, in the structure of the conventional angular velocity sensor, there is a lead terminal for electrically connecting the angular velocity sensor and the outside, and an extension portion is provided in the middle portion thereof. Due to the spring nature of the lead terminal, it can vibrate in a direction perpendicular to the direction in which this extension extends, and this vibration direction is the direction along the direction of vibration detected by the angular velocity detection element in the package, that is, the extension. The part vibrates substantially in the same direction as the detected vibration of the angular velocity detecting element. The lead terminal can be vibrated by the elasticity of the lead terminal in a direction orthogonal to the direction in which the extension portion extends, and the vibration direction of the extension portion is a direction along the direction of the detection vibration of the angular velocity detection element, The vibration of the extension portion of the lead terminal attenuates the disturbance vibration, so that the angular velocity detection element is vibrated.

In general, when the frequency of disturbance vibration, that is, undesirable vibration from the outside, matches the resonance frequency of the system consisting of the element and the package, the element is affected by disturbance vibration, and the sensitivity varies due to amplitude fluctuation of the driving vibration. May change, or vibration modes other than drive resonance may occur. As a result, due to the output with an error as if it is rotating despite no rotation about the rotation axis, a large offset drift occurs that the error output shifts. End up.

  In Patent Document 2, the angular velocity sensor has a connecting member that connects the interior package and the exterior package. This connecting member elastically supports a portion where disturbance is most easily propagated, and plays a role of absorbing disturbance vibration.

  In Patent Document 3, a tuning fork type angular velocity sensor has a detection vibration direction and a driving vibration direction, and the tuning fork type angular velocity sensor is fixed to a pedestal by a support. Thereby, the workability and assembly property of the angular velocity sensor are improved. This support is intended for fixation, not vibration isolation.

9 and 10 are a sectional view and a perspective view of an angular velocity sensor showing the conventional structure shown in Patent Document 1 as a conventional example. For conventional angular velocity sensors, noise resistance and vibration resistance are very important factors for detecting angular velocity without malfunction. For example, in the structure of the conventional angular velocity sensor 100 shown in FIG. 9 and FIG. 10, there is a lead terminal 170 for electrically connecting the angular velocity sensor 100 and the outside, and an extension portion 160 is provided in the middle portion thereof.

The lead terminal 170 can be vibrated in a direction orthogonal to the direction in which the extension 160 extends due to the spring property of the lead terminal 170, and this vibration direction is a direction along the direction of the detected vibration of the angular velocity detecting element 110 in the package 1. That is, the extension 160 vibrates substantially in the same direction as the detected vibration of the angular velocity detecting element 110, that is, in the Y-axis direction in FIGS. The lead terminal 170 can vibrate due to the elasticity of the lead terminal 170 in a direction orthogonal to the direction in which the extension 160 extends, and the Y-axis direction, which is the vibration direction of the extension 160, is detected vibration of the angular velocity detection element 110. This is a direction along the Y-axis direction, which is a direction, and as shown in FIG. 10, the disturbance vibration of the high frequency resonance frequency is attenuated by the vibration of the extension portion 160 of the lead terminal 170, thereby preventing the angular velocity detection element 110. Shaking is done.

In general, when the frequency of disturbance vibration, that is, undesirable vibration from the outside, matches the resonance frequency of the system consisting of the element and the package, the element is affected by disturbance vibration, and the sensitivity varies due to amplitude fluctuation of the driving vibration. May change, or vibration modes other than drive resonance may occur. As a result, due to the output with an error as if it is rotating despite no rotation about the rotation axis, a large offset drift occurs that the error output shifts. End up.

In the conventional example described above, for example, as shown in FIGS. 9 and 10, when the vibration direction of the angular velocity detection element 110 and the detection axis are the same direction, that is, in the example of FIGS. Unnecessary rotational force is generated on the rotation axis, that is, the axis in the direction in which the Z axis extends in the examples of FIGS. In particular, at the resonance frequency generated by the members constituting the package 1, for example, the lead terminal 170 and the package housing 1, the vibration amplitude is large, so that the generated rotational force is also large. As a result, a moment in the direction of the rotation axis is generated, and the yaw rotation, that is, the output with an error as if it is rotating with the Z axis as the axis, that is, the rotation in the Z axis direction has not occurred. As a result, offset drift such as deviation of the error output occurs.

In the case of the conventional example, for example, FIGS. 9 and 10, when the vibration direction of the plate-like extension 160 extending in the predetermined extension direction of the lead terminal 170 of the angular velocity detection element 110 and the Y axis as the detection axis are the same direction, The extension portion 160 of the lead terminal 170 vibrates due to disturbance vibration, and a rotation component different from the rotation that is originally generated is generated with respect to the rotation axis. As a result, an unnecessary Coriolis force is generated, and an offset drift that an output deviation occurs with respect to the normal output value occurs. There is a problem of generating output.

9 and 10, the vibration direction of the extension portion 160 of the lead terminal 170 that vibrates in a direction orthogonal to the direction extending in the extension direction of the plate-like extension portion 160 of the lead terminal 170 and detection. If the Y-axis is the same direction, the entire package becomes Y-axis due to unnecessary vibration due to disturbance vibration in the detection axis direction, that is, Y-axis direction disturbance and lead terminal resonance due to variations in solder amount, device mounting variation, etc. Therefore, it is preferable that the Y axis, which is the detection axis direction, does not coincide with the vibration direction of the extension 160 of the lead terminal 170.

JP 2007-064753 A WO2006 / 132277 JP-A-8-114458

When the vibration direction of the plate-like extension extending in the predetermined extension direction of the lead terminal of the angular velocity detection element and the detection axis are the same direction, the lead terminal vibrates due to disturbance vibration, which is originally generated with respect to the rotation axis. A rotation component separate from the rotation occurs. As a result, an unnecessary Coriolis force is generated, and an offset drift that an output deviation occurs with respect to the normal output value occurs. There is a problem of generating output.

The present invention has been made in consideration of the above points, and provides an angular velocity sensor that reduces offset drift caused by unnecessary rotational force generated by external disturbance vibration.

The present invention is an angular velocity sensor having a package that houses an angular velocity detection element and a lead terminal connected to the package, the angular velocity detection element having a base, a drive arm, and a detection arm, and the drive The arm or the detection arm extends from the base along a first axis, and the lead terminal has a first end connected to the package and a second for connecting to the outside. A plate-like extension having an extending surface extending in a predetermined extending direction between the first end and the second end, and the extension of the lead terminal The surface is an angular velocity sensor including the first axis and orthogonal to a surface orthogonal to the base.

  That is, an extension having a plate-like extending surface in the vicinity of the surface corresponding to the side surface of the package intersecting the rotation axis direction not affected by the disturbance vibration so as not to be affected by the disturbance vibration in the detected vibration direction. A lead terminal having a portion was disposed. Since the plate-like extended surface is arranged in a direction not affected by disturbance vibration, the influence of disturbance vibration can be suppressed, and offset drift caused by unnecessary rotational force caused thereby can be reduced.

According to the present invention, offset drift caused by unnecessary rotational force caused by external disturbance vibration is reduced.

2 is a perspective view of an angular velocity sensor according to Embodiment 1. FIG. 2 is a perspective view of an angle detection element in Embodiment 1. FIG. 2 is a cross-sectional view of an angular velocity sensor according to Embodiment 1. FIG. It is a figure of the mounting state in Embodiment 1. FIG. It is an offset drift characteristic graph of an angular velocity sensor without a lead terminal. It is an offset drift characteristic graph of the angular velocity sensor in the conventional structure. 3 is an angular velocity sensor offset drift characteristic graph according to the first embodiment. It is sectional drawing of the angular velocity sensor in Embodiment 2. FIG. It is sectional drawing of the angular velocity sensor in Embodiment 3. It is sectional drawing of the angular velocity sensor in Embodiment 4. It is sectional drawing of the angular velocity sensor of conventional structure. It is a perspective view of the angular velocity sensor of conventional structure. 3 is a graph showing the resonance frequency dependence of the vibration transmissibility in the first embodiment.

  Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings. In addition, this invention is not limited to the following embodiment. The constituent elements described below include those that can be easily assumed by those skilled in the art and those that are substantially the same. Furthermore, the constituent elements described below can be appropriately combined.

(Embodiment 1)
FIG. 2 is a perspective view of the angular velocity detecting element 11 of the angular velocity sensor 101 according to the first embodiment. First, the principle of angular velocity detection will be described. When an angular velocity Ω about the Z axis is applied while the drive arm 21 is driven to vibrate in the X axis direction, a Coriolis force proportional to the magnitude of the angular velocity in the Y axis direction, which is the detection direction orthogonal to the X axis. Thus, the detection arm 22 is detected and vibrated. A detection electrode is provided on the detection arm 22, and the angular velocity Ω can be detected by detecting the distortion of the piezoelectric thin film 25 generated by the detection vibration of the detection arm 22.

FIG. 1 is a perspective view of an angular velocity sensor 101 according to the first embodiment. In the first embodiment, an angular velocity detecting element 11 that detects an angular velocity by a resonance phenomenon based on an external signal, a package 10 that houses the angular velocity detecting element 11, and a lead terminal that is electrically connected to the angular velocity detecting element 11. 17, the end of the lead terminal 17 of the angular velocity sensor 101 can be vibrated by the elasticity of the extension 16 of the lead terminal 17 while being connected to the package 10.

The lead terminal 17 has a first end 12 connected to the package 10 and a second end 13 for connection to the outside. The first end 12 and the second end 13 are connected to the lead terminal 17. The plate-like extension 16 having an extending surface extending in a predetermined extending direction is included, and the extending surface of the lead terminal 17 includes the first axis and is orthogonal to the base 23. It is orthogonal to the surface to do.

The overall configuration of the angular velocity sensor 101 according to the first embodiment will be described with reference to FIG. The angular velocity sensor 101 includes a package 10, an angular velocity detection element 11, a circuit board 19, and lead terminals 17. The package 10 has an opening, and the angular velocity detection element 11 and the circuit board 19 are accommodated on the bottom surface in the opening. The bottom surface of the package is a surface substantially parallel to the stacking direction of the stacked films, and is disposed substantially parallel to the angular velocity detection element 11 and the circuit board 19. Further, the bottom surface of the package is arranged substantially parallel to the substrate 14.

On the other hand, lead terminals 17 are attached to the outside of the package 10. The angular velocity detecting element 11 and the circuit board 19 and the lead terminal 17 are electrically connected via the in-package wiring and the bonding wire 15.

Next, constituent members will be described below. The package 10 is formed by laminating a plurality of ceramic layers such as alumina and wiring is formed inside or on the surface of the package 10. The firing temperature is 1500 to 1600 ° C., and individualization and terminal attachment are performed after firing. The wiring on the package 10 is obtained by connecting the angular velocity detecting element 11 and the lead terminal 17, and a part of the wiring on the package 10 is exposed to the opening of the package 10 and the package surface. The wiring exposed in the opening is connected to the bonding wire 15, and the wiring exposed on the other surface is electrically and mechanically connected to the end of the lead terminal 17 through solder or the like. The connection between the lead terminal 17 and the wiring exposed on the package surface of the package 10 is brazed with a silver brazing material made of an alloy of silver (Ag) and copper (Cu) or the like, or a high-temperature solder having a melting point of 300 ° C. or higher. Can be a thing.

The angle detection element 11 according to the first embodiment will be described with reference to FIG. FIG. 2 is a perspective view of the angle detection element 11. The angular velocity detecting element 11 is formed by performing well-known fine processing on a semiconductor substrate such as a silicon (Si) substrate having a thickness of about 200 to 500 μm, for example. That is, the angular velocity detection element 11 is made of Si and has a generally known beam-like structure. The angular velocity detection element 11 includes a drive arm 21, a detection arm 22, and a base portion 23.

In FIG. 2, the drive arm 21 or the detection arm 22 extends from the base 23 along the first axial direction, that is, the Z-axis direction corresponding to the longitudinal direction. That is, the drive arm 21 or the detection arm 22 extends and extends along the Z-axis direction. In the present embodiment, the rotation axis is an axis extending along the Z-axis direction.

In FIG. 2, the angular velocity detecting element 11 has a shape that is line-symmetric with respect to an axis that extends along the first axis, that is, an axis that extends along the Z axis.

The lead terminal 17 shown in FIGS. 1 and 3 has a first end portion 12 connected to the package 10 and a second end portion 13 for connecting to the outside, and the first end portion 12 is connected to the outside. Between the first end portion 13 and the second end portion 13, a plate-like extension portion 16 having an extending surface extending in a predetermined extending direction, the extending surface of the lead terminal 17 includes a first axis, and It is orthogonal to the plane orthogonal to the base 23.

In the first embodiment, the lead terminals 17 are arranged as shown in FIG. The first end 12 is connected to the bottom or side of the package 10 by a metal braze. The lead terminal 17 is a surface corresponding to the side surface of the package 10 that intersects the rotation axis, that is, the axis in the direction in which the Z axis extends, that is, a surface corresponding to the side surface of the package 10 that is substantially orthogonal to the axis in the direction in which the Z axis extends. Are connected to the bottom surface in the vicinity of. The side surface of the package 10 is not necessarily perpendicular to the bottom surface of the package 10, but is generally perpendicular. That is, to intersect generally means to be orthogonal.

The lead terminal 17 of the package 10 of the first embodiment is connected in the vicinity of the surface corresponding to the side surface of the package 10 that intersects the direction in which the rotation axis extends, but when excessive heat resistance and airtightness are not required. Similar performance can be obtained by using a plastic mold package. In this case, the manufacturing cost can be reduced. The lead terminals 17 are generally made of a conductive material such as Cu or 42 alloy, and a plurality of lead terminals 17 are provided. Each lead terminal 17 is formed by bending a long and thin plate.

In order to vibrate the angular velocity detecting element 11, a driving piezoelectric thin film 41, a detecting piezoelectric thin film 42, and a base electrode 43 are formed of the same configuration and material on the driving arm 21, the detecting arm 22 and the base 23, respectively. Specifically, as shown in FIG. 3, a first electrode film 24, a piezoelectric thin film 25, and a second electrode film 26 are arranged in this order on the surface of the angular velocity detecting element 11 shown in FIG. The film is formed to a thickness of about several thousand angstroms by sputtering or vapor deposition. 3 is a cross-sectional view taken along the line AA in FIG. 2, and a cross-sectional portion of the angular velocity detecting element 11 corresponds to the base 23.

3 is a cross-sectional view taken along the line AA in FIG. 1, and a cross-sectional portion of the angular velocity detecting element 11 corresponds to the base 23. In FIG. 3, the material of the first electrode film 24 on the surface of the drive arm 21 of the angular velocity detecting element 11 is platinum (Pt) -titanium (Ti) or Pt-chromium (Cr). Further, a piezoelectric thin film 25 such as lead zirconate titanate (PZT) is formed on the first electrode film 24 to a thickness of about several microns (μm). As the film formation method, various film formation methods such as a sputtering method and a solution method can be used. Further, a second electrode film 26 made of a material such as gold (Au), Cr, aluminum (Al), copper (Cu), Ti, Pt or the like is formed on the piezoelectric thin film 25 by a thickness of about several thousand angstroms by sputtering or vapor deposition. A film is formed. Note that the first electrode film is formed by forming Ti as an adhesion layer and a metal thin film Pt in this order.

The angular velocity detection element 11 includes a drive electrode portion (not shown) for generating drive vibration on the drive arm 21, and a detection electrode portion (not shown) for detecting Coriolis force on the detection arm 22. Further, a monitor electrode portion (not shown) for feedback detection is formed in a lump. Photolithography and etching techniques are used to form the electrodes. Etching methods include dry etching, wet etching, lift-off method, and the like, which are appropriately selected depending on the thin film material.

The angular velocity detecting element 11 of the first embodiment shown in FIG. 2 detects an angular velocity Ω with respect to the direction around the rotation axis, that is, the axis extending in the Z-axis direction, based on the Y-axis direction that is the detected vibration direction. is there. Here, in this type of vibration-type angular velocity sensor, the frequencies of the drive vibration and the detection vibration are not particularly determined, but are usually about several thousand Hz, for example.

According to the principle of angular velocity detection, when an angular velocity Ω around an axis extending in the rotation axis, that is, the Z-axis direction is applied when the drive arm 21 is driven to vibrate in the X-axis direction, the detection direction orthogonal to the X-axis is applied. The detection arm 22 is detected and vibrated in the direction of a certain Y axis by a Coriolis force proportional to the magnitude of the angular velocity. A detection electrode is provided on the detection arm 22, and the angular velocity Ω can be detected by detecting the distortion of the piezoelectric thin film 25 generated by the detection vibration of the detection arm 22.

The substrate 14 is a wiring substrate for fixing the package 10 and connecting it to exchange signals with other components. The substrate 14 is generally made of a glass epoxy material or a ceramic material, but is not limited thereto. Further, signal wirings made of Cu are formed on the surface or inside of the substrate 14.

FIG. 3 is a cross-sectional view of the angular velocity sensor 1 according to the first embodiment. 3 is a cross-sectional view taken along the line AA in FIG. 1, and a cross-sectional portion of the angular velocity detecting element 11 corresponds to the base 23.

  In the first embodiment, in order to avoid the influence of disturbance vibration in the detected vibration direction as shown in FIGS. 9 and 10 shown in the conventional example, the rotation axis direction not affected by disturbance vibration as shown in FIG. A lead terminal 17 having an extension portion 16 having a plate-like extending surface in the vicinity of the surface corresponding to the side surface of the package 10 intersecting with the second end portion 13 bent by 90 ° outside the package. Arranged. With such an arrangement, disturbance vibration is suppressed and offset drift caused by unnecessary rotational force generated by the disturbance vibration is reduced.

In the first embodiment, the second end 13, which is the other end of the first end 12 of the lead terminal 17, is surface-connected to the substrate 14 made of glass epoxy or ceramic, With respect to the extending surface of the plate-like extension portion 16, it is bent toward the outside in the Z-axis direction, that is, toward the outside of the package 10. Further, the substrate mounting surface, that is, the XZ plane, and the lead extending direction, that is, the Y-axis direction are approximately 90 °.

  In particular, as Embodiment 1, in FIG. 3, the vibration direction that vibrates in the direction orthogonal to the direction extending in the extending direction of the extension portion 16 of the lead terminal 17 of the package 10 is the rotation axis direction, that is, the Z-axis direction in FIG. , And are formed so as to substantially match.

In general, when the frequency of disturbance vibration, that is, undesirable vibration from the outside, matches the resonance frequency of the system consisting of the element and the package, the element is affected by disturbance vibration, and the sensitivity varies due to amplitude fluctuation of the driving vibration. May change, or vibration modes other than drive resonance may occur. As a result, a large offset drift occurs.

Therefore, in the first embodiment, a vibration phenomenon of a vibration system including the package 10 that houses the angular velocity detection element 11, the lead terminals 17 connected to the package 10, and the substrate 14 that fixes the lead terminals 17 will be considered. When ωp is the package resonance frequency due to vibration at the lead terminal, ω is the frequency of drive vibration, and ξ is the damping factor, the vibration transmissibility T can be described by the equation (1).

FIG. 11 shows a graph of the frequency dependence of the vibration transmissibility T when ξ is 0.3, that is, ξ is a material constant. The vertical axis represents the vibration transmissibility T [dB], and the unit is log of the ratio of the generated vibration energy and the vibration energy after being attenuated. The horizontal axis represents the frequency ratio ω / ωp, which is normalized by the resonance frequency of the vibration system constituted by the lead terminal 17 connected to the package 10 and the substrate 14 that fixes the lead terminal 17. In FIG. 11, the fact that the vibration transmissibility T has a peak when ω / ωp is 1 means that ω and ωp approach each other and resonate, and the damping effect disappears.

From the result of FIG. 11, when the frequency ω / ωp is smaller than 1.4 shown by the broken line, the vibration transmissibility T exceeds 1 and the vibration is amplified. As a result, the drive frequency ω resulting from the bending of the first end portion 12 and the second end portion 13 of the lead terminal 17 is 40% or more away from the resonance frequency ωp in the resonance mode. It was possible to prevent a malfunction.

FIG. 4 shows a mounting state related to the first embodiment, and the manufacturing method of the angular velocity sensor 1 of the first embodiment will be described using this.

As shown in FIG. 4, the angular velocity detection element 11 is die-bonded to the ceramic package 10, that is, the angular velocity detection element is bonded to the package 10 with a resin 32. As the die bonding resin 32, an epoxy resin, an acrylic resin, or the like is used. A dispenser was used as a resin coating device. The coating conditions at this time are 50 kPa and 0.2 sec, and the coating amount is about 1 μg. Furthermore, a die bonder was used for mounting the elements. The chip mounting pressure is 3N, and the pressure application time is 3 sec. Thereafter, the resin was cured by heating with an oven, a hot plate or the like.

Next, as shown in FIG. 4, wire bonding is performed between an electrode pad (not shown) on the angular velocity detecting element 11 and a pad (not shown) of the ceramic package 10, and electrical connection with the package 10 is performed. went. Au is generally used as the material of the wire 15, but is not limited as long as it is a material that can easily ensure electrical connection, such as Cu and Al. The thickness of the Au wire is 25 μm, the intensity of the ultrasonic wave is about 1 kW, and the bond weight is about 30 g.

After obtaining electrical connection with the outside by wire bonding, sealing as shown in FIG. 4c is performed in order to reduce the influence from the external atmosphere. The sealing lid 34 is generally made of a material such as Kovar made of an alloy of Fe, Ni, and Co. As a sealing means, a seam welding method, that is, a method of welding while passing an electric current is used. A pulse current of 5 msec was used, and the current value was 1 kA. The sealing atmosphere was nitrogen. If the element has sufficient heat resistance, it is also possible to use heat bonding with AuSn solder.

In the first embodiment, since a circuit board and an adhesive are used in addition to the angular velocity detection element 11 and the package 10, the circuit board and the adhesive will be described. The circuit board 19 is configured as a signal processing chip having a function of sending a drive or detection signal to the angular velocity detection element 11, processing an electrical signal from the angular velocity detection element 11, and outputting it to the outside. Such a circuit board 19 is configured by an IC chip or the like in which a MOS transistor, a bipolar transistor, or the like is formed using a known semiconductor process, for example, on a Si substrate or the like.

Each part of the angular velocity detecting element 11, the circuit board 19 and the package 10 is electrically connected via a bonding wire 15. In this way, the electrical signal from the angular velocity detection element 11 is sent to the circuit board 19, converted into a voltage signal, and output as an angular velocity signal. The angular velocity signal is output to the outside via the lead terminal 17. One end of the lead terminal 17 is fixed to the package 10 and electrically connected to the mounting member. As this attachment member, a printed circuit board, a wiring substrate such as a ceramic substrate, or a connector member can be adopted. Therefore, the angular velocity signal of the angular velocity sensor 101 is output to a mounting member as a printed board via the lead terminal 17.

On the other hand, on the bottom of the opening of the package 10, the circuit board 19 and the angular velocity detecting element 11 are sequentially mounted and fixed via a resin adhesive 32. As this resin adhesive 32, a general adhesive can be employed, and for example, a resin adhesive such as silicone gel or an adhesive film such as silicon, epoxy, polyimide, and acrylic is used.

(Embodiment 2)
FIG. 6 is a cross-sectional view of the angular velocity sensor 102 according to the second embodiment. FIG. 6 particularly shows the shape of the lead terminal 172 of the second embodiment.

The second end portion 132 of the lead terminal 172 shown in the second embodiment is curved inward as viewed from the cross section of the package 10, and the cross section of the curved portion has a substantially constant radius of curvature. As a result, surface mounting with an occupied area smaller than that of the first embodiment is possible. In addition, since the shape of the lead terminal 172 is less likely to generate vibration nodes, that is, if a vibration node is formed, higher-order package vibrations are generated, which is close to driving vibrations. Can be obtained.

The first end 12 of the lead terminal 172 is connected to the bottom surface of the package 10 by a metal braze, while the lead terminal 172 extends in the Y-axis direction, which is the detection axis direction, and the second end of the other end of the lead. 132 is surface-connected to a substrate 14 made of glass epoxy or ceramic.

The second end portion 132 of the lead terminal 172 is curved inward as viewed from the cross-sectional direction of the package 10, and the cross section of the curved portion has a shape that maintains a substantially constant radius of curvature. The vibration direction that vibrates in a direction orthogonal to the direction extending in the extending direction of the extension portion 16 of the lead terminal 172 is the direction along the axis of rotation of the angular velocity detecting element 11, that is, the axis extending substantially in the Z-axis direction. Therefore, generation of moment due to yaw rotation can be suppressed, and the same offset drift reduction effect as in the first embodiment can be obtained.

In the second embodiment, as in the first embodiment, the influence of the disturbance vibration as shown in FIG. 6 is reduced so as not to be affected by the disturbance vibration in the detection vibration direction as shown in FIGS. A lead terminal 172 having a plate-like extension portion 16 and a second end portion 132 having a curved portion is disposed in the vicinity of the surface corresponding to the side surface of the package 10 that intersects the rotational axis direction that is not received. With such an arrangement, disturbance vibration is suppressed and offset drift caused by unnecessary rotational force generated by the disturbance vibration is reduced.

(Embodiment 3)
FIG. 7 is a cross-sectional view of the angular velocity sensor 103 according to the third embodiment. FIG. 7 particularly shows the shape of the lead terminal 173 of the third embodiment.

The first end 12 of the lead terminal 173 is fixed to the bottom surface of the package 10 with a metal brazing, while the lead terminal 173 extends in the detection axis direction, that is, the Y-axis direction, and the second end of the other end of the lead. 13 is surface-mounted on a substrate 14 made of glass epoxy or ceramic.

In the third embodiment, the extending direction of the extension portion 163 of the lead terminal 173 extends slightly in the Y axis direction as shown in FIG. That is, the lead terminal 173 extends smoothly.

Thereby, since the extending direction of the extension part 163 of the lead terminal 173 is inclined, the package resonance frequency in the rotational axis direction of the angular velocity detecting element 11, that is, the Z-axis direction is slightly increased, so that the suppression effect Although it is somewhat damaged, there is an advantage that processing variations are unlikely to occur because lead processing is easy. The vibration direction that vibrates in the direction orthogonal to the direction extending in the extending direction of the extension portion 163 of the lead terminal 173 is the direction along the rotation axis direction of the angular velocity detecting element 11, that is, the axis extending in the general Z-axis direction. Therefore, the generation of moment due to yaw rotation can be suppressed, and the same offset drift reduction effect as in the first embodiment can be obtained.

In the third embodiment, as in the first embodiment, the influence of the disturbance vibration as shown in FIG. 7 is reduced so as not to be affected by the disturbance vibration in the detection vibration direction as shown in FIGS. In the vicinity of the surface corresponding to the side surface of the package 10 that intersects the direction of the rotation axis that is not received, a lead terminal 173 having a plate-like extension 163 that extends smoothly outside the package is disposed. With such an arrangement, disturbance vibration is suppressed and offset drift caused by unnecessary rotational force generated by the disturbance vibration is reduced.

(Embodiment 4)
FIG. 8 is a cross-sectional view of the angular velocity sensor 104 according to the fourth embodiment. FIG. 8 particularly shows the shape of the lead terminal 174 of the fourth embodiment.

While the first end 12 of the lead terminal 174 is connected to the bottom surface of the package 10 by a metal braze, the lead terminal 174 extends in the detection axis direction, that is, the Y-axis direction. The end 134 is connected to the substrate 14 made of glass epoxy or ceramic.

Since the second end portion 134 of the lead terminal 174 in the fourth embodiment is mounted on a glass epoxy substrate or a ceramic substrate by DIP (Dual In-line Package), the extension portion 16 of the lead terminal 174 and the second end portion 134 are mounted. Extends straight and penetrates the substrate 14 and is soldered from the back side, so there is no need to bend the second end portion 134. The vibration direction that vibrates in the direction orthogonal to the direction extending in the extending direction of the extension portion 16 of the lead terminal 174 is the direction along the rotation axis direction of the angular velocity detecting element 11, that is, the axis extending in the Z-axis direction. Therefore, the occurrence of moment due to yaw rotation can be suppressed, and the same offset drift reduction effect as in the first embodiment can be obtained.

In the fourth embodiment, as in the first embodiment, the influence of the disturbance vibration as shown in FIG. 8 is reduced so as not to be affected by the disturbance vibration in the detection vibration direction as shown in FIGS. A lead terminal 174 having a plate-like extension 16 that passes straight through the substrate 14 is disposed in the vicinity of the surface corresponding to the side surface of the package 10 that intersects the rotational axis direction that is not received. With such an arrangement, disturbance vibration is suppressed and offset drift caused by unnecessary rotational force generated by the disturbance vibration is reduced.

The element characteristic of Embodiment 1, that is, the effect on the offset drift with respect to the frequency will be described with reference to FIGS. In order to show the effect of Embodiment 1, the offset drift in the vibration test was measured. The excitation frequency is 50 Hz to 20 kHz, and the magnitude of the excitation is 98 m / s ² (10 G).

FIG. 5A shows a vibration resistance characteristic result when the angular velocity detection element 11 of the first embodiment has no lead terminal 17 and the package 10 is directly mounted on the substrate 14. According to this, in the vicinity of the excitation frequencies of 5000 Hz and 15000 Hz, since there is no lead, external vibration is directly applied to the angular velocity detection element 11, and a large offset drift of 15 deg / sec occurs.

Furthermore, as shown in the conventional example of Patent Document 1, that is, as shown in FIGS. 9 and 10, the vibration direction that vibrates in the direction orthogonal to the direction extending in the extending direction of the extension portion 16 of the lead terminal 13, and the detection axis, that is, the Y axis. When mounted in the same direction, that is, in the Y-axis direction, as shown in FIG. 5b, offset drift of 10 deg / sec and 4 deg / sec occur near 1000 Hz and near 3300 Hz. Is insufficient.

However, when implemented as in Embodiment 1, as shown in FIG. 5c, the offset drift was almost zero, which was below the noise level. This is presumably because unnecessary output due to occurrence of unnecessary rotation in the detection axis direction can be sufficiently reduced. By mounting as in the first embodiment, unnecessary vibration of yaw rotation can be suppressed, and offset drift can be reduced.

From the above evaluation results, according to the first embodiment, the rotating shaft without disturbance vibration as shown in FIG. 1 is used so as not to be affected by the disturbance vibration in the detection vibration direction as shown in FIGS. By arranging the lead terminal 17 having the plate-like extension portion 16 in the vicinity of the surface corresponding to the side surface of the package 10 that intersects the direction, disturbance vibration is suppressed, which is caused by unnecessary rotational force generated by the disturbance vibration. It has been found that offset drift can be reduced.

  In addition to Embodiment 1, that is, Embodiments 2 to 4 were also checked for offset drift using the same evaluation method as described above. Table 1 shows the evaluation results of the offset drift for the conventional example shown in FIGS. 9, 10, and 5 b and the first to fourth embodiments. In the evaluation result of the conventional example already shown in FIG. 5b, the offset drift amount was 10 deg / sec. However, in each of the first to fourth embodiments, it is below the evaluation result of FIG. Similar to the result of the first embodiment, it was almost zero and below the noise level. Therefore, in any of Embodiments 1 to 4, it was confirmed that there was an effect of reducing the offset drift as compared with the conventional example. From the above results, it was found that by arranging such lead terminals, disturbance vibration can be suppressed and offset drift caused by unnecessary rotational force generated by the disturbance vibration can be reduced.

Summarizing the above evaluation results, that is, according to the present embodiment, it is possible to suppress the influence of external disturbance vibration and reduce offset drift caused by unnecessary rotational force caused by the disturbance vibration. I was able to show that.

1, 10 Package 100, 101, 102, 103, 104, 105 Angular velocity sensor 11, 110 Angular velocity detection element 12 First end portion 13, 132, 134 Second end portion 14 Substrate 15 Bonding wire 16, 163 Lead terminal Extension part 17, 170, 172, 173, 174, 175 Lead terminal 19 Circuit board 21 Drive arm 22 Detection arm 23 Base part 24 First electrode film 25 Piezoelectric thin film 26 Second electrode film 32 Resin adhesive 34 Lid 41 For driving Piezoelectric thin film 42 Piezoelectric thin film 43 for detection Base electrode

Claims (8)

An angular velocity sensor having a package for housing an angular velocity detection element and a lead terminal connected to the package,
The angular velocity detection element has a base, a drive arm, and a detection arm,
The drive arm or the detection arm extends from the base along a first axis;
The lead terminal has a first end connected to the package and a second end for connecting to the outside, and a predetermined end is provided between the first end and the second end. A plate-like extension having an extending surface extending in the extending direction of
The extending surface of the lead terminal includes the first axis and is orthogonal to a surface orthogonal to the base portion. The angular velocity sensor according to claim 1, wherein the drive arm and the detection arm are arranged on opposite sides with respect to the base portion of the angular velocity detection element. 3. The angular velocity sensor according to claim 1, wherein there are two drive arms and two detection arms. The angular velocity sensor according to claim 1, wherein the first end portion is bent with respect to an extending direction of the extension portion. The first end portion and the second end portion are bent with respect to the extending direction of the extension portion, and the second end portion is bent outward with respect to the package. The angular velocity sensor according to claim 4. The first end portion is bent approximately 90 ° with respect to the extending direction of the extension portion, and the second end portion is curved inward with respect to the package. The angular velocity sensor according to claim 4, wherein Of the resonance mode of the vibration system configured by the package that houses the angular velocity detection element, a lead terminal connected to the package, and a substrate that fixes the lead terminal, a first end of the lead terminal; The angular velocity sensor according to any one of claims 1 to 6, wherein the resonance frequency of the resonance mode due to the second end portion being bent is separated by 40% or more compared to the drive frequency of the element. The angular velocity sensor according to claim 1, wherein the second end is connected to a substrate.

Images