JP2007198774A - Inertial force sensor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an inertial force sensor capable of detecting a plurality of inertia forces different from each another, such as angular velocity and acceleration, detecting an inertia force on a plurality of detection axes, and achieving compactness of various types of electronic apparatuses. <P>SOLUTION: The inertial force sensor is provided with a detection element 1 for detecting inertial forces. The detection element 1 comprises four driving arms 2; a support part 4 for supporting one end parts of the driving arms 2; and two fixing arms 6 to be connected to the support part 4 and fixed to a mounting substrate. One fixing arm 6 is arranged between two driving arms 2, and the other fixing arm 6 is arranged between the other two driving arms 2. <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 including four drive arms, a support part supporting one end of the drive arm, and a support board connected to the support part. Two fixing arms for fixing, one fixing arm is disposed between the two driving arms, and the other fixing arm is disposed between the other two driving arms. This is the configuration.

  With the above configuration, when the four driving arms are arranged in different XY axis directions and the fixing arm is arranged in the Y axis direction with respect to the X axis, Y axis, and Z axis orthogonal to each other, For example, if the driving arm is driven and oscillated in the X-axis direction, the distortion caused by the angular velocity around the Z-axis can be generated in the X-axis direction of the fixing arm, and the distortion caused by the angular velocity around the Y-axis is It can be generated in the Z-axis direction of the drive arm 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 X-axis direction of the fixing arm, 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 axes 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.

  In FIG. 1, an inertial force sensor according to an embodiment of the present invention includes a detection element 1 that detects inertial force and a processing circuit (not shown). The detection element 1 includes four drive arms 2, a support portion 4 that supports one end of the drive arm 2, and is connected to the support portion 4 and fixed to a mounting board (not shown). Two fixing arms 6, one fixing arm 6 is disposed between one two driving arms 2, and the other fixing arm 6 is disposed between the other two driving arms 2. It is the arranged configuration.

  In addition, the detection element 1 has two fixing arms 6 arranged on substantially the same straight line, and the four drive arms 2 are arranged in mutually different XY axis directions on the X axis, Y axis, and Z axis orthogonal to each other. The fixing arm 6 is arranged in the Y-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, the driving arm 2 is driven to vibrate, and the fixing arm 6 detects the distortion.

  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 driving arm 2 is driven to vibrate in the X-axis direction (a solid line arrow and a dotted line arrow are alternately repeated) as shown in FIG. Can be generated in the X-axis direction of the fixing arm 6 (because Coriolis force is generated in the Y-axis direction of the driving arm 2 in response to driving vibration), and is caused by the angular velocity around the Y-axis. The generated distortion can be generated in the Z-axis direction of the fixing arm 6 (because Coriolis force is generated in the Z-axis direction of the driving arm 2 in response to driving vibration). Is possible.

  As for the acceleration, for example, distortion caused by acceleration in the X-axis direction can be generated in the fixing arm 6 (because the weight of the driving arm 2 is applied to the fixing arm 6), and by detecting this distortion 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, so that the mounting area can be reduced and the size can be reduced.

  In addition, when a weight part is connected to the both ends of the driving arm 2, acceleration detection can be further improved, and the amplitude in the driving vibration is increased, the sensitivity of the angular velocity is improved, and the acceleration detection is further improved. Can do.

  Further, as shown in FIG. 3, the other end of the driving arm 2 may be connected via a connecting arm 8. In FIG. 3, two connecting arms 8 are provided, and the fixing arm 6 is provided in parallel with the connecting arm 8. In this case, regarding the angular velocity, if the driving arm 2 is driven to vibrate in the X-axis direction (solid arrows and dotted arrows are alternately repeated), the distortion caused by the angular velocity around the Z-axis is Y in the connecting arm 8. It can be generated in the axial direction (solid arrows and dotted arrows are alternately repeated) (because Coriolis force is generated in the Y-axis direction of the driving arm 2 in response to driving vibration), and the angular velocity around the Y-axis Can be generated in the Z-axis direction of the fixing arm 6 (because Coriolis force is generated in the Z-axis direction of the driving arm 2 in response to driving vibration), and by detecting this distortion Detection is possible.

  With regard to acceleration, for example, distortion caused by acceleration in the Y-axis direction can be generated in the Y-axis direction of the fixing arm 6 (because the weight of the driving arm 2 is applied to the fixing arm 6). Detection is possible by detection.

  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 perspective 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 Operational state diagram of detection elements of other inertial force sensors

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Detection element 2 Drive arm 4 Support part 6 Fixing arm 8 Connection arm

Claims (6)

It has a detection element that detects inertial force,
The detection element has four drive arms, a support part that supports one end of the drive arm, and two fixing arms that are connected to the support part and fixed to a mounting board, One inertial arm is disposed between one of the two driving arms, and the other fixing arm is disposed between the other two driving arms. The inertial force sensor according to claim 1, wherein the two fixing arms are arranged on substantially the same straight line. The inertial force sensor according to claim 1, wherein the driving force is vibrated to detect an angular velocity by detecting distortion of the fixing arm. The inertial force sensor according to claim 1, wherein an acceleration is detected by detecting distortion of the fixing arm. The inertial force sensor according to claim 1, wherein the other end of the driving arm is connected via a connecting arm. The inertial force sensor according to claim 1, wherein a weight portion is connected to the other end portion of the driving arm.

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