JP2005257637A - Mounting structure of vibrator - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a mounting structure that can easily mount a plurality of vibrators on the same substrate under the condition that the detection axis A is aligned, in the mounting structure where a plurality of the vibrators using for measuring a physical quantity corresponding to a predetermined detection axis. <P>SOLUTION: The mounting structure mounts a plurality of the vibrators using for measuring the physical quantity ω corresponding to the predetermined detection axis A, wherein at least a part of the vibrator is formed along a predetermined face and a plurality of the vibrators are stacked the vertical direction D to the predetermined face. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a mounting structure for mounting a plurality of vibrators used for measuring a physical quantity corresponding to a predetermined detection axis.

  The use of a vibratory gyroscope has been studied for a rotational speed sensor used in a vehicle control method of an automobile body rotational speed feedback type. In such a system, the direction of the steering wheel itself is detected by the rotation angle of the steering wheel. At the same time, the rotational speed at which the vehicle body is actually rotating is detected by the vibration gyroscope. Then, the direction of the steering wheel is compared with the actual rotational speed of the vehicle body to obtain a difference, and based on this difference, correction is made to the wheel torque and the steering angle, thereby realizing stable vehicle body control.

In a technique using a vibration type gyroscope to control the direction of a steered wheel, it is necessary to prevent the control angle of the steered wheel from being distorted due to a malfunction or error of the vibration type gyroscope. For this reason, in Patent Document 1, three or more front wheel steering angle detection means for detecting the front wheel steering angle by different methods are used, and the front wheel steering angle detected by any of the front wheel steering angle detection means is used as a detection output. The front wheel steering angles detected by the three or more front wheel steering angle detectors are compared with each other to determine the coincidence of the front wheel steering angles. In this case, if it is determined that the detection result of the front wheel steering angle detection means, which is the detection output by the front wheel steering angle output means, does not coincide with any detection result of the other front wheel steering angle detection means, this detection is performed. It is determined that there is an abnormality in the steering angle detection means giving the output.
Patent No. 3018749

  The present inventor obtains a rotational angular velocity detection value from each vibration gyroscope by mounting a plurality of vibration gyroscopes on a circuit board, and from other detection values among the plurality of detection values. We investigated the removal of detected values that were far apart and using the remaining detected values as measured values. Accordingly, when a measurement error of one vibration gyroscope or vibrator becomes large or breaks, a detection value from the vibration gyroscope can be excluded from the measurement result.

  However, it has been found that the process of mounting a plurality of vibrators on a circuit board in this manner is relatively difficult. For example, when a plurality of planar vibrators are mounted on a circuit board, it is necessary to mount them with the detection axes of the vibrators aligned. This is because if the detection axes of the transducers are shifted from each other on the circuit board, the detection values from the transducers differ when the same rotational angular velocity is applied. However, the vibrator is a small electronic component, and the dimensions of the vibrator are extremely small, particularly in mobile phone applications. Therefore, the process of mounting the vibrator on the circuit board is a rather difficult and complicated process. At this time, it is difficult to mount a plurality of vibrators on the same circuit board with the detection axes accurately aligned.

  An object of the present invention is to provide a mounting structure in which a plurality of transducers used for measuring a physical quantity corresponding to a predetermined detection axis are mounted, with a plurality of transducers on the same substrate and with detection axes aligned. It is to provide a structure that can be easily mounted.

  The present invention is a mounting structure for mounting a plurality of vibrators used to measure a physical quantity corresponding to a predetermined detection axis, wherein at least a part of the vibrator is formed along a predetermined surface, and the plurality of vibrations The child is laminated in a direction substantially perpendicular to the predetermined plane.

  According to the present invention, a plurality of vibrators are stacked in a direction substantially perpendicular to a predetermined plane to obtain a mounting structure including a plurality of vibrators. In this mounting structure, since the arrangement direction of the plurality of transducers is geometrically determined, as a result, alignment is performed so that the directions of the detection axes of the transducers are the same. By mounting the mounting structure thus obtained on a target circuit board, a plurality of vibrators are mounted on the circuit board in a state where the detection axes are aligned.

  In a preferred embodiment, each vibrator is mounted on a support substrate. In this case, it is easy to geometrically align the detection axes of the transducers by laminating the support substrates in a direction substantially perpendicular to the main surface.

  In this embodiment, a plurality of support substrates can be directly joined to each other and integrated. The joining method in this case is not particularly limited, and may be various methods such as an ultraviolet curable adhesive, a thermosetting adhesive, and mechanical fixing. Alternatively, each support substrate can be accommodated in a separate small package, and a plurality of small packages can be joined together and integrated. The joining method in this case is not particularly limited, and may be various methods such as an ultraviolet curable adhesive, a thermosetting adhesive, and mechanical fixing.

  In a preferred embodiment, an electronic component is mounted on the support substrate. However, it is not essential to mount electronic components on each support substrate, and electronic components for driving a plurality of vibrators and processing output signals can be combined into one.

  The detection axis of the vibrator may be equal to the mounting direction, but may be different from the mounting direction. In a preferred embodiment, the detection axis of the vibrator is substantially perpendicular to the predetermined plane. In another preferred embodiment, the detection axis of the vibrator is substantially parallel to the predetermined plane.

  In a preferred embodiment, the mounting structure of the present invention is housed in a package. In this case, by mounting the package on the circuit board, the plurality of vibrators are mounted on the circuit board with the detection axes aligned.

  In the present invention, at least a part of the vibrator is formed along the predetermined surface, but the whole vibrator may be formed along the predetermined surface. Further, the angle formed by the predetermined plane and the stacking direction of the vibrators is substantially vertical. This is intended not only to be vertical in a geometrically strict sense, but also to allow a normal degree of error in the mounting technology. For example, it may be shifted by 3 ° from the geometrical vertical.

  Hereinafter, the present invention will be described in more detail with reference to the drawings as appropriate.

  FIG. 1 is a schematic view schematically showing a vibrator housing package 11A (11B, 11C) used in an embodiment of the present invention, and FIG. 2 is a schematic view showing a mounting state of the vibrator in the package of FIG. 3A is a plan view of the inside of the package of FIG. 2, and FIG. 3B is a bottom view of the package of FIG.

  In this example, the mounting structure 1A (1B, 1C) of each vibrator 4 is accommodated in the package container 8. The vibrator 4 is formed along the predetermined plane X. The support substrate 32 has a flat plate shape and has one opposing surface 32a and the other opposing surface 32b. On the one opposing surface 32 a, a separate frame 13 is further installed by the bonding wire 14, and the lower surface of the vibrator 4 is supported on the frame 13 by the bonding wire 5. The bonding wires 5 and 14 are electrically connected to electrodes (not shown) on the vibrator 4. The electronic component 6 is supported by bumps 7 on the other facing surface 32b. The electrode terminals on the vibrator 4 and the terminals of the electronic component 6 are connected to the electrodes on the substrate 32 through bonding wires, respectively.

  In this example, the vibrator 4 and the electronic component 6 are installed at positions that do not substantially overlap each other when projected in the thickness direction of the substrate 32. The mounting structures 1A, 1B, and 1C are accommodated in a package container 8, and constitute a package 1A (1B and 1C). Not limited to this example, an air hole (not shown) is provided in the package container 8 so that the vibrator is operated by evacuating the package.

  The package 11A (11B, 11C) is fixed on each substrate 2A (2B, 2C) as shown in FIG. At this time, the detection axis A of each vibrator is substantially perpendicular to a predetermined surface on which each vibrator 4 is formed, and is substantially perpendicular to the substrates 2A, 2B, and 2C. In this example, the rotational angular velocity ω around the detection axis A is detected using each vibrator 4.

  Next, each of the packages 11A, 11B, 11C and the supporting substrates 2A, 2B, 2C are stacked in the direction of arrow D and integrated as shown in FIG. A mounting structure 3 is obtained. The joining method in this case is not particularly limited, and may be various methods such as an ultraviolet curable adhesive, a thermosetting adhesive, and mechanical fixing. In this example, the stacking direction D is the same as the detection axis A.

  Next, a predetermined number of leads 10 are attached to the substrate 11A as indicated by an arrow B, and the mounting structure 3 is accommodated in the package 16 shown in FIG. Predetermined terminals are provided on the bottom surface of the package, and the package 16 is mounted on a predetermined circuit board.

  Also, a mounting structure as shown in FIGS. 6 and 7 can be employed. In the mounting structure 3 </ b> A shown in FIG. 6, for example, three packages 11 </ b> A, 11 </ b> B, and 11 </ b> C are integrated by a flexible substrate 12. In this example, the flexible substrate 12 is bent and includes flat plate mounting portions 12a, 12b, and 12c that fix the packages 11A, 11B, and 11C, and bent portions 12d and 12e that connect the mounting portions. In this example, the mounting structure 11A is sandwiched between the mounting parts 12a and 12b, and the mounting structure 11B is sandwiched between the mounting parts 12b and 12c.

  The mounting structure 3B shown in FIG. 7 includes flat plate mounting portions 2A, 2B, and 2C that fix the packages 11A, 11B, and 11C, and wirings 20 that connect the mounting portions. In this example, the package 11A is sandwiched between the mounting portions 2A and 2B, and the package 11B is sandwiched between the mounting portions 2B and 2C.

  The dimensions of the vibrator are not limited. However, if the weight and dimensions of the vibrator are large, gravity applied to the bonding wire increases, and the bonding wire may be deformed after a long period of time. For this reason, from the viewpoint of suppressing the influence on the vibration due to the deformation of the bonding wire, the width of the vibrator is preferably 10 mm or less, and more preferably 5 mm or less. From the same viewpoint, the weight of the vibrator is preferably 5 mg or less, and more preferably 1 mg or less. Further, the thickness of the vibrator is preferably 0.3 mm or less, more preferably 0.2 mm or less.

Preferably, the resonator element is made of a piezoelectric single crystal. Examples of the piezoelectric single crystal include quartz, LiNbO ₃ , LiTaO ₃ , lithium niobate-lithium tantalate solid solution (Li (Nb, Ta) O ₃ ) single crystal, lithium borate single crystal, and langasite single crystal.

  As the driving means and detection means in the vibrator, any means that is normal in the field of the vibration gyroscope can be adopted. When the vibrator is formed of a piezoelectric material, the vibrator is provided with a drive electrode and a detection electrode as drive means and detection means. Examples of the piezoelectric material include piezoelectric ceramics such as PZT in addition to the piezoelectric single crystal. In addition, when the vibrator is formed of a constant elastic metal, piezoelectric ceramics can be pasted on the vibrator as a driving means and a detection means.

  The material of the substrate is not particularly limited, and insulating materials used for so-called package applications such as ceramics, glass, and resin can be used.

  In the embodiment in which the substrate is bent as shown in FIG. 6, a flexible substrate is used. This is a soft and thin film-like circuit board, and generally a board in which copper wiring is provided on a polyimide film is often used. Due to its high degree of freedom in design, it has recently been adopted in many electronic products that are becoming smaller and more precise.

  As shown in FIG. 7, when the flat mounting portions are connected by the wiring 20, the wiring is continuous with and electrically connected to the wirings constituting the electrode pattern on each mounting portion, for example. Good. In this way, by using the wiring of the substrate as the connecting portion, it is not necessary to bend the flexible substrate, so that the manufacturing becomes easier. Although the kind of wiring 20 is not specifically limited, Copper foil, copper foil with gold plating, aluminum foil, and nickel foil are preferable.

  The bonding wire may be supported directly on the mounting surface of the support substrate, but may be supported on a frame on the support substrate. Further, the bonding method of the bonding wire to the vibrator is not limited, but ultrasonic bonding, spot welding, conductive adhesive, and soldering are preferable.

  The bonding wire can be electrically connected to the terminal portion of the vibrator. Further, the material of the bonding wire is not particularly limited, but it needs to be a conductive material, and is preferably a material having flexibility or flexibility. From this viewpoint, copper with gold plating, nickel with gold plating, nickel, and aluminum are preferable.

  The upper surface of the vibrator can be supported by the bonding wire, or the lower surface of the vibrator can be supported by the bonding wire.

  The physical quantity to be measured in the present invention is not particularly limited. When the vibration state of the vibrator is changed due to the influence of the physical quantity on the vibrator during driving vibration, the physical quantity that can be detected through the detection circuit from the change in the vibration state is targeted. . As such physical quantities, acceleration, angular velocity, and angular acceleration applied to the vibrator are particularly preferable. Further, an inertial sensor is preferable as the measuring device.

  In the present invention, the package 16 or the mounting structures 3, 3A, 3B is fixed to a predetermined circuit board. This fixing method is not limited, and may be various methods such as an ultraviolet curable adhesive, a thermosetting adhesive, mechanical fixing, and soldering of the lead 10.

  The type of electronic component mounted on the support substrate is not particularly limited, but examples include a resistor resistor, a capacitor, and a semiconductor integrated circuit chip. The type of chip is not particularly limited, but it is preferably a semiconductor integrated circuit that processes the output signal of the angular velocity sensor. For example, an operational amplifier that constitutes a filter, an analog / digital converter that digitizes analog output, or a digitized signal Is preferably a serial communication driver that outputs the data to the outside via serial communication. When there is a terminal that can be directly connected to the vibrator from the outside of the angular velocity sensor, it is preferably a semiconductor integrated circuit chip that controls the drive signal and detection signal of the vibrator, for example, an ASIC (Application Specified Integrated Circuit). ) Is preferred.

The method for sealing the vibrator into the package is not limited, and examples thereof include the following methods.
(1) The sealing means is a semiconductor chip package. As such a package, QFP (Quad Flat Package)
Examples of the package include a QFN (Quad Flat No-lead) package.
(2) The sealing means is a resin mold material. Examples of the resin molding material include epoxy resin, silicone resin, polyimide resin, and urethane resin.
(3) The sealing means is a ceramic package. The cover is preferably seam welded or solder welded or gold soldered.
(4) The sealing means is a metal package. An example of the material is Kovar.
(5) The sealing means is a metal bent casing. Although it is not hermetically sealed, it is effective as an electromagnetic shield. Examples of the material include galvanized steel sheets and stainless steel.

FIG. 5 is a perspective view showing transducer housing packages 11A, 11B, and 11C used in an embodiment of the present invention, and substrates 2A, 2B, and 2C that fix the packages. It is sectional drawing which shows the packages 11A, 11B, and 11C schematically. (A) is a top view which shows the inside of package 11A, 11B, 11C, (b) is a bottom view of a package. It is a perspective view which shows the mounting structure 3 obtained by laminating | stacking package 11A, 11B, 11C and board | substrate 2A, 2B, 2C. It is a perspective view of the package 16 which accommodates a mounting structure. It is a perspective view which shows 3A of mounting structures provided with the packages 11A, 11B, and 11C laminated | stacked using the flexible substrate 12 and this. FIG. 5 is a perspective view showing a mounting structure 3B formed by connecting substrates 2A, 2B, and 2C with wirings 20;

Explanation of symbols

  1A, 1B, 1C Mounting structure of vibrator in package 2A, 2B, 2C Substrate 3, 3A, 3B Mounting structure 4 vibrator 5 Bonding wire 8 Package container 10 Lead 11A, 11B, 11C Package for housing vibrator 16 package 11A, 11B, 11C package 12 Flexible substrate 20 Wiring A Detection axis D Direction substantially perpendicular to the predetermined plane X X predetermined plane ω Rotational angular velocity

Claims (6)

A mounting structure for mounting a plurality of vibrators used for measuring a physical quantity corresponding to a predetermined detection axis,
At least a part of the vibrator is formed along a predetermined plane, and the plurality of the vibrators are stacked in a direction substantially perpendicular to the predetermined plane. Implementation structure.   The mounting structure according to claim 1, wherein the vibrator is mounted on a support substrate.   The mounting structure according to claim 2, wherein an electronic component is mounted on the support substrate.   The mounting structure according to claim 1, wherein the detection axis of the vibrator is substantially perpendicular to the predetermined surface.   The mounting structure according to claim 1, wherein the mounting structure is housed in a package.   The mounting structure according to claim 1, wherein the vibrator is a vibrator for measuring a rotational angular velocity around the detection axis.

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