JP2007198780A - Inertial force sensor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an inertial force sensor for detecting a plurality of inertial forces different in 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 the inertial force. The detector element 1 is provided with two orthogonal axis type arms formed by approximately orthogonally connecting the first arm 2 and second arm 4, and the supporting part 8 for supporting two first arms 2, and two fixing arms 10 connecting to the supporting part 8 with one end and to the mounted substrate (not illustrated) with the other end. The fixing arm 10 is a orthogonal axis type arm formed by connecting the third arm 12 to the fourth arm 14 approximately in a orthogonal direction, and both ends of the fourth arm 14 are bent so as to oppose to the third arm 12, and fixed to the mounted substrate at both the ends of the fourth arm 14. <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, the present invention particularly provides a detection element that supports two orthogonal arms formed by connecting a first arm to a second arm in a substantially orthogonal direction, and supports the two first arms. And two fixing arms that are connected to the support portion and fixed to the mounting substrate, and the fixing arm is an orthogonal arm formed by connecting the third arm to the fourth arm in a substantially orthogonal direction. Further, both ends of the fourth arm are bent so as to face the third arm and fixed to the mounting substrate at both ends of the fourth arm.

  With the above configuration, when the first arm and the fourth arm are arranged in the Y-axis direction and the second arm and the third arm are arranged in the X-axis direction with respect to the X axis, the Y axis, and the Z axis orthogonal to each other, As for the angular velocity, for example, if the second arm is driven to vibrate in the Y-axis direction, the distortion caused by the angular velocity around the Z-axis can be generated in the X-axis direction of the first arm. The resulting distortion can be generated in the Z-axis direction of the first and second arms, and can be detected by detecting this distortion.

  As for the acceleration, for example, distortion caused by acceleration in the X-axis direction can be generated in the first arm, and distortion caused by acceleration in the Y-axis direction can be generated in the third arm. It can be detected if it is detected.

  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 plan 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 two orthogonal arms formed by connecting the first arm 2 to the second arm 4 in a substantially orthogonal direction, a support portion 8 that supports the two first arms 2, and one end on the support portion 8. And two fixing arms 10 for fixing the other end to a mounting substrate (not shown). The fixing arm 10 is an orthogonal arm formed by connecting the third arm 12 to the fourth arm 14 in a substantially orthogonal direction, and both ends of the fourth arm 14 are bent so as to face the third arm 12 and the fourth arm 14. The arm 14 is fixed to the mounting board at both ends. Further, weight portions 16 are connected to both ends of the second arm 4.

  In this detection element 1, the first arm 2 and the support portion 8 are arranged on substantially the same straight line, the third arm 12 and the support portion 8 are arranged on substantially the same straight line, and the first arm 2 and the third arm are arranged. 12 are arranged in a substantially orthogonal direction, and the first arm 2 and the fourth arm 14 are arranged in the Y axis direction on the X axis, the Y axis, and the Z axis orthogonal to each other, and the second arm 4 and the third arm The arm 12 is arranged in the X-axis direction.

  Further, the detection element 1 is integrally formed from a silicon substrate. On this silicon substrate, a drive electrode is disposed on an arm for driving vibration, and a detection electrode is disposed on an arm for detecting strain. In this detection element 1, the arm for driving vibration is the second arm 4, and the arm for detecting distortion is the first arm 2, the second arm 4, and the third arm 12.

  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 with a resonance frequency at which silicon resonates is applied to the lower electrode and the upper electrode, the arm on which the drive electrode is arranged vibrates and if the arm is distorted due to angular velocity or acceleration, it is placed on the distorted arm. A voltage corresponding to the strain is output from the detected electrode. Based on this output voltage, the processing circuit can detect the angular velocity and acceleration.

  With the above configuration, for example, as shown in FIG. 2, if the second arm 4 is driven to vibrate in the Y-axis direction (along with a solid line arrow and a dotted line arrow) as shown in FIG. Can be generated in the X-axis direction of the first arm 2 (because Coriolis force is generated in the X-axis direction of the second arm 4 in response to driving vibration), and is caused by the angular velocity around the X-axis. Can be generated in the Z-axis direction of the second arm 4, the third arm 12, and the fourth arm 14 (because Coriolis force is generated in the Z-axis direction of the second arm 4 in response to the drive vibration). Detection is possible by detecting this distortion.

  As for acceleration, for example, distortion caused by acceleration in the X-axis direction can be generated in the third arm 12 (because the weight of the second arm 4 is applied to the third arm 12), and is caused by acceleration in the Y-axis direction. This distortion can be generated in the fourth arm 14 (because the weights of the second arm 4 and the third arm 12 are added to the fourth arm 14), and can be detected by detecting this distortion.

  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 the weight part 16 is connected to both ends of the second arm 4, the acceleration detection sensitivity can be improved, and the amplitude in the drive vibration can be increased to improve the angular velocity detection sensitivity.

  Moreover, if both ends of the second arm 4 are bent to face the second arm 4, and further, both ends of the second arm 4 are bent in a meander shape to face the second arm 4. The above effects can be further 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 1st arm 4 2nd arm 8 Support part 10 Fixing arm 12 3rd arm 14 4th arm 16 Weight part

Claims (8)

It has a detection element that detects inertial force,
The detection element includes two orthogonal arms formed by connecting the first arm to the second arm in a substantially orthogonal direction, a support portion that supports the two first arms, a support substrate that is connected to the support portion, and a mounting substrate. Two fixing arms that are fixed to each other, the fixing arm being an orthogonal arm formed by connecting the third arm to the fourth arm in a substantially orthogonal direction, and bending both ends of the fourth arm. An inertial force sensor that is opposed to the third arm and is fixed to the mounting substrate at both ends of the fourth arm. The inertial force sensor according to claim 1, wherein both end portions of the fourth arm are bent so as to face the fourth arm. The first arm and the support portion are arranged on substantially the same straight line, the third arm and the support portion are arranged on substantially the same straight line, and the first arm and the third arm are substantially orthogonal to each other. The inertial force sensor according to claim 1 arranged in a direction. The inertial force sensor according to claim 1, wherein the second arm is driven to vibrate, and the angular velocity is detected by detecting distortion of the fixing arm. The inertial force sensor according to claim 1, wherein acceleration is detected by detecting distortion of the fourth arm. The inertial force sensor according to claim 1, wherein weight portions are connected to both end portions of the second arm. The inertial force sensor according to claim 1, wherein both end portions of the second arm are bent so as to face the second arm. The inertial force sensor according to claim 1, wherein both end portions of the second arm are bent in a meander shape so as to face the second arm.

Images