JP2007198778A - Inertial force sensor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an inertial force sensor for detecting a plurality of inertial forces that mutually differ in the angular velocities, or acceleration etc., capable of detecting the inertial forces of a plurality of detector axes, or capable of miniaturizing various electronic equipment. <P>SOLUTION: The inertial sensor is provided with the detector element 1 for detecting inertial force. The detector element 1 is provided with a constitution of 4 arms 2 and the base 4 for connecting one end of the arms 2, and for fixing to a mounted substrate (not shown), and the arms 2 are arranged in orthogonal directions to each other, while mutually connecting the other ends of the arms 2 via the connection arms 6. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an inertial force sensor that detects an inertial force used in various electronic devices such as attitude control and navigation of a moving body such as an aircraft, an automobile, a robot, a ship, and a vehicle.

  Hereinafter, a conventional inertial force sensor will be described.

  Conventionally, when an inertial force sensor that detects an inertial force such as an angular velocity or acceleration is used, a dedicated angular velocity sensor is used to detect the angular velocity, and a dedicated acceleration sensor is used to detect the acceleration. In addition, when detecting angular velocities and accelerations of a plurality of detection axes with respect to the X axis, Y axis, and Z axis orthogonal to each other, a plurality of angular velocity sensors and acceleration sensors are used so as to correspond to the number of detection axes. It was.

  Therefore, when various angular velocity and acceleration are detected in combination with various electronic devices, or when angular velocity and acceleration are detected for multiple detection axes, multiple angular velocity sensors and acceleration sensors are mounted on various electronic devices. Each was mounted on a board.

  In general, an angular velocity sensor detects an angular velocity by electrically detecting a distortion of a detection element caused by the generation of Coriolis force by vibrating a detection element having various shapes such as a sound shape, an H shape, and a T shape. The acceleration sensor has a weight part, and detects acceleration by comparing and detecting the movement of the weight part accompanying the acceleration with that before the movement.

  A plurality of inertial force sensors such as an angular velocity sensor and an acceleration sensor are used in an attitude control device, a navigation device, and the like of a moving body such as a vehicle, corresponding to the inertial force and detection axis to be detected.

For example, Patent Document 1 and Patent Document 2 are known as prior art document information related to the invention of this application.
JP 2001-208546 A JP 2001-74767 A

  In the above configuration, when detecting the inertial force of various electronic devices, a plurality of inertial force sensors such as an angular velocity sensor and an acceleration sensor are mounted on the mounting board of the various electronic devices corresponding to the inertial force and detection axis to be detected. Therefore, it is necessary to secure a mounting area for mounting a plurality of inertial force sensors, and there is a problem that various electronic devices cannot be reduced in size.

  The present invention solves the above problems and does not require a mounting area for mounting a plurality of inertial force sensors, detects a plurality of different inertial forces such as angular velocity and acceleration, or detects a plurality of detection axes. An object of the present invention is to provide an inertial force sensor that can detect inertial force and can reduce the size of various electronic devices.

  In order to achieve the above object, in particular, the present invention provides a detection element having four arms and a support part for supporting one end of the arm, and connecting the other end of the arm to each other. It is the structure connected via.

  With the above configuration, when a pair of connecting arms facing each other orthogonal to the X axis, Y axis, and Z axis are arranged in the X axis direction, for example, for angular velocity, the connecting arm is driven to vibrate in the Y axis direction. By doing so, distortion caused by the angular velocity around the Z axis can be generated in the XY axis direction of the arm, and distortion caused by the angular velocity around the Y axis can be generated in the Z axis direction of the arm. It can be detected by detecting.

  As for the acceleration, for example, distortion caused by acceleration in the X-axis direction and acceleration in the Y-axis direction can be generated in the connecting arm, and can be detected by detecting these distortions.

  Therefore, a plurality of different inertia forces can be detected, or the inertia forces of a plurality of detection shafts can be detected, so that the mounting area can be reduced and the size can be reduced.

  FIG. 1 is a perspective view of a detection element of an inertial force sensor according to an embodiment of the present invention, and FIG. 2 is an operation state diagram of the detection element.

  In FIG. 1, an inertial force sensor according to an embodiment of the present invention includes a detection element 1 for detecting inertial force and a processing circuit (not shown). The detection element 1 includes four arms 2 and a support portion that supports one end of the arm 2, and the support portion serves as a base portion 4 that is fixed to a mounting substrate (not shown). In particular, the arms 2 are arranged orthogonal to each other and the other ends of the arms 2 are connected to each other via a connecting arm 6.

  In the detection element 1, the connecting arms 6 facing each other are arranged substantially in parallel, and one of the opposing connecting arms 6 is arranged in the X-axis direction on the X, Y, and Z axes orthogonal to each other. The other connecting arm 6 facing is disposed in the Y-axis direction.

  Further, the detection element 1 is integrally formed from a silicon substrate. On the silicon substrate, a driving electrode is disposed on a connecting arm 6 for driving vibration, and a detection electrode is disposed on an arm 2 for detecting strain. .

  For the drive electrode and the detection electrode, for example, a lower electrode of Pt is formed on a silicon substrate by high frequency sputtering, a PZT piezoelectric body is formed on the upper portion of this lower electrode by high frequency sputtering, and an upper portion is formed by Au evaporation on the upper portion. What is necessary is just to form by forming an electrode.

  When an alternating voltage having a resonance frequency at which silicon resonates is applied to the lower electrode and the upper electrode, each of the connecting arms 6 on which the driving electrodes are arranged vibrates so that the central portion thereof becomes an antinode, and also due to angular velocity and acceleration. When the arm 2 is distorted, a voltage corresponding to the strain is output from the detection electrode disposed on the distorted arm 2. Based on this output voltage, the processing circuit can detect the angular velocity and acceleration.

  With respect to the angular velocity, for example, as shown in FIG. 2, for example, as shown in FIG. 2, one opposing connecting arm 6 is driven in the X axis direction, and the other connecting arm 6 is driven in the Y axis direction (solid arrow and dotted arrow). Can be generated in the XY-axis direction of the arm 2 (Coriolis force corresponds to the drive vibration in one of the connecting arms 6 in the Y-axis direction). In addition, since the other connecting arm 6 is generated in the X-axis direction and the connecting arm 6 tries to rotate around the base 4), distortion caused by the angular velocity around the Y-axis is generated in the Z-axis direction of the arm 2. (Coriolis force is generated in the X-axis direction of the connecting piezoelectric substrate 6 corresponding to the drive vibration), and detection is possible by detecting this distortion.

  As for acceleration, for example, distortion caused by acceleration in the X-axis direction and acceleration in the Y-axis direction can be generated in the connecting arm 6 (because the weight of the connecting arm 6 is applied to the connecting arm 6), and this distortion is detected. By doing so, detection is possible.

  Therefore, a plurality of different inertia forces can be detected, or the inertia forces of a plurality of detection shafts can be detected, and the mounting area can be reduced and the size can be reduced.

  In addition, when a notch part is provided in the center part of the connection arm 6, the connection arm 6 becomes easy to move, and the detection sensitivity of acceleration and the detection sensitivity of angular velocity can be improved.

  The inertial force sensor according to the present invention can detect a plurality of inertial forces or detect inertial forces of a plurality of detection shafts, and can be applied to various electronic devices.

The top view of the detection element of the inertial force sensor in one embodiment of this invention Operation state diagram of detection element of the same inertial force sensor

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Detection element 2 Arm 4 Base 6 Connection arm

Claims (5)

It has a detection element that detects inertial force,
The detection element includes four arms and a support portion that supports one end of the arm, and the other end of the arm is connected to each other via a connecting arm. The inertial force sensor according to claim 1, wherein the connecting arms facing each other are arranged substantially in parallel. The inertial force sensor according to claim 1, wherein the connecting arm is driven to vibrate, and the angular velocity is detected by detecting distortion of the arm. The inertial force sensor according to claim 1, wherein an acceleration is detected by detecting distortion of the connecting arm. The inertial force sensor according to claim 1, wherein a cut portion is provided in a central portion of the connection arm.

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