JP2005043306A - Oscillating gyro sensor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a precise horizontal tuning fork type oscillating gyro sensor that has excellent resistance to vibration impact and can cope with miniaturization. <P>SOLUTION: The oscillating gyro sensor comprises a doublet-tuning fork-shaped quartz resonator 1, a support 2 made of quartz, a base 3 having a plurality of lead terminals 4, and a metal lid 5 having a recess that is open downward. The quartz resonator 1 is placed nearly at the center on the mounting surface of the base 3 and the upper surface of the support 2 is joined to the lower surface end of first and second support fixing sections 21, 23 by using an adhesive. In this case, the support 2 is fixed to a position corresponding to the first and second support fixing sections 21, 23 of the quartz resonator 1 via the adhesive. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a vibration gyro sensor that solves various problems that occur when packaging a piezoelectric vibrator using Coriolis force.

As a sensor for detecting the rotation of an object, a sound type vibration gyro sensor using Coriolis force is widely used. In particular, a sound-type vibration gyro sensor called a horizontal horizontal type is easy to be thinned and miniaturized, and thus has a wide range of applications such as camera shake prevention and car navigation systems.
In recent years, horizontal and horizontal sound-type vibration gyro sensors have been researched for vehicle travel control applications. Vehicle travel control is a lifeline that determines the safety of the entire vehicle, and a vibration gyro sensor for this application is particularly required to have excellent vibration resistance and high accuracy.

A conventional horizontal horizontal sound type vibration gyro sensor is disclosed in, for example, Japanese Patent Laid-Open No. 11-281372, and FIG. 3 is an exploded perspective view showing the configuration thereof. These are the top views of the piezoelectric vibrator concerning the conventional vibration gyro sensor.
As shown in FIG. 3, the conventional vibration gyro sensor includes a piezoelectric vibrator 100, a ceramic package 110 having a concave portion 111 for accommodating the piezoelectric vibrator 100 on the upper surface, and an opening for the concave portion 111. And a metal lid 120. As shown in FIG. 4, the piezoelectric vibrator 100 has a base 100 </ b> A having a four-fold symmetrical square centered on the center of gravity G (intersection of a one-dot chain point in the figure) and one end of the base 100 </ b> A facing each other. The drive vibration systems 101A and 101B are composed of T-shaped drive vibration systems 101A and 101B protruding from the sides and strip-shaped detection vibration systems 102A and 102B protruding from the other opposite sides. The center of gravity G is a two-fold symmetry, and the detection vibration systems 102A and 102B are two-fold symmetric about the center of gravity G.
A support tool 112 projecting substantially at the center of the inner bottom surface of the recess 111 and a through-hole 113 drilled in the center of gravity G are fitted and mechanically connected by an adhesive (not shown) (supported at one point), and piezoelectric. The vibrator 100 and the ceramic package 110 are electrically connected by wire bonding (not shown), and the opening of the recess 111 is hermetically sealed by the metal lid 120.
JP-A-11-281372

  However, a conventional horizontal horizontal sound type vibration gyro sensor has a one-point support structure and a small mounting area. For this reason, when vibration or impact is applied from the outside, the vibration or impact tends to concentrate on the support portion of the sensor (piezoelectric vibrator 100). There is a high risk of breakage under environmental conditions. Further, when the entire sensor is downsized, there is a problem that the impact is more easily concentrated on the support portion. Furthermore, stress strain due to a difference in thermal expansion coefficient is applied to the support portion, which also affects the piezoelectric vibrator 100 and may impair the stability (such as aging characteristics) of the piezoelectric vibrator 100.

  That is, the problem to be solved is that it is not possible to provide a horizontal horizontal sound type vibration gyro sensor that is excellent in vibration shock resistance, is highly accurate, and can cope with downsizing.

  In order to solve the above-mentioned problems, according to a first aspect of the present invention, there is provided a vibration gyro sensor using a piezoelectric vibrator having a twin tone shape, wherein the piezoelectric vibrator disposed horizontally and horizontally, the piezoelectric vibrator, And a support made of the same material.

  According to a second aspect of the present invention related to the present invention, in the first aspect, the support is provided at both ends of the piezoelectric vibrator.

  According to a third aspect of the present invention related to the present invention, in the second aspect, the piezoelectric vibrator and the support are separate members and are joined to each other.

  A fourth aspect of the present invention according to the present invention is characterized in that in the second or third aspect, quartz is used as a material for the piezoelectric vibrator and the support.

  A fifth aspect of the present invention according to the present invention is characterized in that, in the fourth aspect, the crystal is cut so that the normal direction of the principal surface thereof is the Z axis of the crystal axis.

  The vibration gyro sensor of the present invention is capable of providing a vibration gyro sensor that is excellent in vibration shock resistance, highly accurate, and can be miniaturized, in particular, a horizontal horizontal type double-tone vibration gyro sensor. There are advantages.

  Hereinafter, the present invention will be described in detail based on illustrated embodiments of the present invention.

FIG. 1A is a top view of a horizontal transverse type dual sound type vibration gyro sensor (hereinafter referred to as a “vibration gyro sensor”) as a first embodiment of the present invention in a state where a metal lid is omitted. FIG. 1B is a longitudinal sectional view taken along the line AA, and FIG. 2 is a plan view of the crystal resonator according to the first embodiment.
The vibration gyro sensor as the first embodiment is a metal having a twin-tone crystal resonator 1, a support 2 made of crystal, a base 3 having a plurality of lead terminals 4, and a recess opening downward. And a lid 5. As shown in FIG. 2, the quartz crystal resonator 1 is formed by forming a Z-plate crystal flake cut so that the normal direction of the main surface of the substrate is in the crystal Z-axis direction into a double-tone shape by wet etching. A predetermined electrode is formed by vapor deposition or sputtering, and has a pair of strip-shaped arm portions 11a and 11b, and a drive portion 13 having drive electrodes 12a and 12b formed on the surfaces of the arm portions 11a and 11b; The first and second sympathetic support portions 14 and 15 including the lead electrode 13a that supports both ends of the drive unit 13 and is connected to the drive electrodes 12a and 12b, and the first detection electrodes 16a and 16b are provided. A first detector 17 for detecting vibrations of the arms 11a and 11b via the first bisonality support 14 and a second detection electrode 18a and 18b; A second detection unit 19 that detects vibrations of the arms 11a and 11b via a second harmonic support unit 15 and one end of the first detection unit 17 and the first detection electrode are supported. A first support fixing part 21 having a pair of lead electrodes 20a and 20b connected to 16a and 16b, and a pair supporting one end of the second detection part 19 and connecting to the second detection electrodes 18a and 18b. And a second support fixing portion 23 having lead-out electrodes 22a and 22b. Note that the drive electrode, the first and second detection electrodes, the electrode pattern of the lead electrode, and the electrode pattern of the lead electrode shown in FIG. Has been.
The support body 2 is formed by wet etching to form a Z-plate crystal piece cut so that the normal direction of the substrate main surface is the crystal Z-axis direction so as to substantially match the support space included in each support fixing portion. Is.

  The quartz crystal unit 1 is placed at substantially the center of the mounting surface (upper surface) of the base 3, and an adhesive (not shown) is provided at a position corresponding to the first and second support fixing portions 21 and 23. The upper surface of the support body 2 fixed in this manner and the lower surfaces of the first and second support fixing portions 21 and 23 are joined using an adhesive (not shown) (two-point support). By adopting such a joining method, even if the joint portion is reduced in area due to downsizing of the vibration gyro sensor, that is, downsizing of the crystal unit 1 (support fixing part) and the support 2, sufficient impact resistance is achieved. In addition, since the support 2 is made of quartz, stress distortion due to a difference in coefficient of thermal expansion is not applied to the joint portion, and stability (aging characteristics, etc.) of the crystal unit 1 is not impaired. However, the crystal axis directions of the crystal unit 1 and the support 2 may be different from each other as long as the adhesive is soft and can relieve the stress strain.

  The lead terminal 4 protruding from the mounting surface of the base 3 is connected to the lead electrode and the lead electrode corresponding to the lead terminal 4 by wire bonding (not shown).

  The difference between the resonance frequency of the drive unit 13 and the first and second detection units 17 and 19, that is, the detuning frequency is detuned to a desired value, and then the crystal unit 1 is moved by the metal lid 5. Seal hermetically. Note that a one-chip IC that constitutes an offset adjustment circuit, a gain adjustment circuit, and the like together with the crystal resonator 1 can be disposed, for example, on the mounting surface of the base 3.

The vibration gyro sensor according to the second embodiment of the present invention is different from the first embodiment in that the lower surface of the first and second support fixing portions (the surface facing the mounting surface of the base). The support body is integrally formed.
The quartz crystal resonator according to the second embodiment is formed to have a desired thickness and a double-tone shape by wet etching except for a portion to be a support on one main surface of a Z-plate crystal piece as a material. A predetermined electrode is formed on the surface by vapor deposition or sputtering. With such a structure, there is an effect that the mounting operation of the crystal resonator (according to the second embodiment) is simplified.

  Needless to say, the present invention is not limited to the crystal resonator element, and can be applied to a vibrator made of other piezoelectric materials such as langasite, lithium tetragonal acid, lithium tantalate, and lithium niobate.

It is the schematic block diagram which showed the structure of the vibration gyro sensor which concerns on this invention. (A) The top view of the state which abbreviate | omitted the metal cover. (B) AA longitudinal cross-sectional view. 1 is a plan view of a crystal resonator according to the present invention. It is the disassembled perspective view which showed the structure of the conventional vibration gyro sensor. It is a top view of the conventional crystal oscillator.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Crystal oscillator 2. Support body 3. Base 4 ... Lead terminal 5 ... Metal lid 11a, 11b ... Arm part 12a, 12b ... Drive electrode 13 ... Drive part 13a ... Lead electrode 14 ··· First harmonic support 15 ··· Second harmonic support 16a, 16b · · First detection electrode 17 · · First detection portion 18a and 18b · · · Second detection electrode 19 .. second detection part 20a, 20b .. extraction electrode 21 .. first support fixing part 21
22a, 22b... Extraction electrode 23.. 2nd support fixing part 100.. Piezoelectric vibrator 100A ... Base 101A, 101B ... Drive vibration system 102A, 102B ... Detection vibration system 110 ... Ceramic package 111 ... Recessed part 112 ・ ・ Support 113 ・ ・ Through hole 120 ・ ・ Metal lid G ・ ・ Center of gravity

Claims (5)

In a vibration gyro sensor using a twin-tone shape piezoelectric vibrator,
A vibration gyro sensor comprising the piezoelectric vibrator arranged horizontally and a support made of the same material as the piezoelectric vibrator. The vibration gyro sensor according to claim 1, wherein the support is provided at both lower portions of the piezoelectric vibrator. The vibration gyro sensor according to claim 2, wherein the piezoelectric vibrator and the support are separate members and are joined to each other. 4. The vibration gyro sensor according to claim 2, wherein quartz is used as a material for the piezoelectric vibrator and the support. 5. The vibration gyro sensor according to claim 4, wherein the crystal is cut so that a normal direction of a main surface thereof is a Z axis of a crystal axis.

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