JP2016070739A - Sensor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a sensor that restrains variation of sensitivity between three axes.SOLUTION: A sensor includes a fixed part 10 arranged on one plane, a weight part 20 arranged with a space from the fixed part 10, and a connection part 30 that connects the fixed part 10 and the weight part 20, holds the weight part 20, and is deformed according to the displacement of the weight part 20. In the connection part 30, a length along a virtual line connecting the centers of the fixed part 10 and the weight part 20 in plan view is shorter than in the weight part 20. In the weight part 20, the center of gravity is located at the side of a connected portion to the connection part 30 in a thickness direction with reference to a half point of a length in the thickness direction.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a sensor with little variation in sensitivity in three axes.

  An angular velocity sensor having a vibration-type sensor element is used to measure the running state of a car, the movement state of a robot, and the like.

  8A and 8B are diagrams showing a conventional sensor element. FIG. 7A is a plan view, and FIG. 7B is a cross-sectional view taken along line B-B ′ in FIG.

  The sensor element shown in the figure is formed in a weight part 101, a frame-like fixing part 102 surrounding the weight part 101, a beam part 103 connected to the weight part 101 and the fixing part 102, and a beam part 103. Piezoresistive element 104.

  The weight part 101, the fixing part 102, and the beam part 103 are integrally formed by processing a silicon substrate.

  The piezoresistive element 104 is formed by implanting boron into the surface of the silicon substrate.

  In such a sensor element, when an angular velocity about a rotation axis parallel to the longitudinal direction of the beam portion 103 is generated in a state where the beam portion 103 is vibrated, the weight portion 101 moves, and the beam portion 103 is deformed accordingly. The piezoresistive element 104 is also deformed.

  The angular velocity is detected based on a change in resistance value due to the deformation of the piezoresistive element 104.

  Therefore, in order to improve the detection sensitivity of the angular velocity, it is sufficient that the beam portion 103 is easily deformed, and a device for increasing the volume of the weight portion 101 has been conventionally made (see, for example, Patent Document 1).

JP 2003-172745 A

  Such a sensor element can detect the angular velocity in the three-axis directions of XYZ by the arrangement and connection of the piezoresistive elements 104, but the sensitivity in the three-axis directions may vary.

  The present invention has been conceived under the above-described circumstances, and an object thereof is to provide a sensor with little variation in sensitivity of three axes.

A sensor according to an embodiment of the present invention includes a fixed portion, a weight portion arranged at a distance from the fixed portion, and the fixed portion and the weight portion, which are arranged in a plane. A connecting portion that connects and holds the front weight portion and deforms according to the displacement of the weight portion, the connecting portion connecting the fixed portion and the center of the weight portion in plan view The length along the imaginary line is shorter than that of the weight portion, and the weight portion has a center of gravity in the thickness direction that is connected to the connection portion from half of the length in the thickness direction. It is located in.

  According to the present invention, it is possible to provide a sensor with little variation in the sensitivity of three axes.

It is a top view showing a schematic structure of a sensor concerning one embodiment of the present invention. It is sectional drawing which shows schematic structure of the sensor which concerns on one Embodiment of this invention. It is a diagram which shows the relationship between the length of a connection part, and the resonant frequency. It is the top view and principal part sectional drawing which show the modification of a combination of a weight part and a connection part. (A)-(d) is principal part sectional drawing which shows the modification of a weight part, respectively. (A), (b) is the schematic which shows the sensor 100B which concerns on an Example, and the sensor which concerns on a comparative example, respectively. (A), (b) is the top view and sectional drawing which show the conventional sensor, respectively.

  An embodiment of a sensor of the present invention will be described with reference to the drawings.

  FIG. 1 is a plan view of a sensor 100 according to an embodiment of the present invention, and FIG. 2 is a cross-sectional view taken along line II-II in FIG. The sensor 100 is arranged on one plane (XY plane), the frame-shaped fixing part 10, the weight part 20 located inside the fixing part 10, and the connection for connecting the fixing part 10 and the weight part 20. And a detection unit R that is disposed in the connection unit 30 and detects an electrical signal corresponding to the deformation of the connection unit 30. In the following, one plane (XY plane) is simply a plane, the first direction constituting one plane and the second direction orthogonal to the first direction are the X direction / Y direction, and the direction perpendicular to the one plane is the Z direction or the thickness direction. There is.

  The sensor 100 can detect the angular velocity by rotating the weight portion 20 in the XY plane. In order to rotate the weight part 20, for example, electrodes may be provided on the outer wall of the weight part 20 facing each other and the inner wall of the fixing part 10 by electrostatic attraction, or on the outside of the sensor 100. It may be realized by generating a magnetic force. Alternatively, a driving piezoelectric element may be disposed in a plurality of connection portions 30, and electrical signals may be sequentially input to the piezoelectric elements, and the connection portions 30 may be sequentially deformed to be rotated. When an angular velocity is applied to the sensor 100, Coriolis force acts on the weight part 20, and the weight part 20 moves, so that the connection part 30 is twisted. Then, an electrical signal corresponding to the deformation amount of the connecting portion 30 is detected by the detecting portion R, and the angular velocity can be detected by taking out and calculating the electrical signal with an electrical wiring (not shown).

  The sensor 100 can also detect acceleration. When acceleration is applied to the sensor 100, a force corresponding to the acceleration acts on the weight part 20, and the connection part 30 is bent by moving the weight part 20. The acceleration can be detected by detecting an electrical signal corresponding to the amount of deflection of the connecting portion 30 by the detecting portion R and taking out and calculating the electrical signal with an electrical wiring (not shown). Hereinafter, each part will be described in detail.

The weight part 20 has a substantially square planar shape. The weight part 20 shown in this example has a different planar shape between a part connected to a connection part 30 described later and a part located below the connection part 30. The site | part connected with the connection part 30 of the weight part 20 and the site | part located below are arrange | positioned so that a center may mutually overlap. In addition, in FIG. 1, the planar shape of the site | part located below is shown with the broken line.

  As for the size of the part connected to the connection part 30 of the weight part 20, the length of one side of the substantially square is set to, for example, 0.25 mm to 0.5 mm. Moreover, the thickness of this site | part is set to 5 micrometers-20 micrometers, for example. The size of the part located below in plan view is set such that the length of one side of a substantially square is 0.4 mm to 0.65 mm, for example. Moreover, the thickness is set to 0.2 mm-0.625 mm, for example. The part connected with the connection part 30 and the site | part located below among such weight parts 20 may be joined by another member. For example, the part connected to the connection part 30 in the weight part 20, the part located below, and the joining part for joining both are integrally formed by processing an SOI (Silicon on Insulator) substrate. May be. In this case, the bonding portion is composed of an oxide layer between Si. The joining part has substantially the same planar shape as the part connected to the connecting portion 30. And the connection site | part has the small planar shape compared with the site | part located below. Thereby, the connection part 30 and the site | part located under the connection part 30 among the weight parts 20 can be isolate | separated, and the mobility of the weight part 20 can be ensured.

  And the shape of the weight part 20 in the thickness direction is such that the center of gravity is located above half of the length in the thickness direction. That is, half of the length in the thickness direction is the Z coordinate of the virtual gravity center position G0 when it is assumed that the weight portion 20 as shown by the dotted line in FIG. 2 has a uniform planar shape in the thickness direction. Compared to the Z coordinate, the shape is such that the actual center-of-gravity position G1 is located on the upper side (the side connected to the connecting portion 30). In this example, the cross-sectional area in a plane parallel to one plane is smaller on the side farther from the connection part 30 than the side connected to the connection part 30 from the Z coordinate of the virtual center of gravity position G0, so that the center of gravity position G1 is reduced. It is adjusted. More specifically, it has a tapered shape in which the cross-sectional area in a plane parallel to one plane gradually decreases from the middle in the thickness direction. By setting it as such a structure, the actual gravity center position G1 can be shifted to the connection part 30 side rather than the virtual gravity center position G0.

  And the frame-shaped fixing | fixed part 10 is provided so that such a weight part 20 may be surrounded. The fixed portion 10 has a substantially square opening in the center, and has a substantially square opening that is slightly larger than the weight portion 20 at the center. The length of one side of the fixing portion 10 is set to, for example, 1.4 mm to 3.0 mm, and the width of the arm constituting the fixing portion 10 (the width in the direction perpendicular to the longitudinal direction of the arm) is, for example, 0.3 mm to It is set to 1.8 mm. Moreover, the thickness of the frame 10 is set to 0.2 mm-0.625 mm, for example.

  A connecting portion 30 is provided between the fixed portion 10 and the weight portion 20 as shown in FIGS. The connection part 30 holds the weight part 20 in a state where the displacement according to the displacement of the weight part 20 is possible.

  The connection portion 30 has a shorter length in the virtual line L that connects the fixed portion 10 and the weight portion 20 and extends in a direction parallel to one plane (XY plane) than the weight portion 20. The imaginary line passes through the center of the weight 20 in the XY plane.

  Specifically, the connection portion 30 has a first end 31 that is one end coupled to the center portion on the upper surface side of each side of the weight portion 20, and a second end 32 that is the other end is an inner periphery of the fixed portion 10. Are connected to the center of the upper surface side of each side. In the sensor 100 according to this embodiment, four connection portions 30 are provided, and two of the four connection portions 30 extend in the X-axis direction and have the same straight line with the weight portion 20 interposed therebetween. The other two are arranged in the same straight line extending in the Y-axis direction and sandwiching the weight portion 20 therebetween. The length from the first end 31 to the second end 32, which is the length along the extending direction of the connecting portion 30, is shorter than the length of the weight portion 20 in the extending direction.

  Note that the length of the weight portion 20 in the extending direction is defined on the surface to which the connection portion 30 is connected. Further, as in the present embodiment, when there are connection portions 30 on both sides of the weight line 20 on the imaginary line L, the length of the connection portion 30 is the distance between the both sides of the weight portion 20. The length of one side until it arrives at the weight part 20 from the fixing | fixed part 10 shall be pointed out instead of the sum total.

  By adopting such a configuration, the connection portion 30 has a resistance to displacement in the extending direction (X direction and Y direction parallel to one plane) smaller than resistance to displacement in the Z direction. As a result, when it is assumed that the weight part having a fixed shape is connected to the connection part 30, the resonance frequency in the Z direction is higher than the resonance frequency in the X direction and the Y direction.

  In this example, the connection part 30 has a beam shape. For this reason, the ease of displacement of the connecting portion 30 in the extending direction and the ease of displacement of the connecting portion 30 in the Z direction can also be evaluated by the cross-sectional second moment of the connecting portion 30. That is, the connecting portion 30 has a cross-sectional secondary moment in the X direction and the Y direction that is smaller than the cross-sectional secondary moment in the Z direction, so that the connecting portion 30 has its extending direction (the X direction parallel to one plane, The resistance to displacement in the Y direction can be made smaller than the resistance to displacement in the Z direction. As a result, when it is assumed that the connection portion 30 is connected to a weight portion having a uniform shape, the resonance frequency in the Z direction becomes higher than the resonance frequency in the X direction and the Y direction.

  In addition to the configuration in which the length from the first end 31 to the second end 32 which is the length along the extending direction of the connecting portion 30 is shorter than the length of the weight portion 20 in the extending direction, When the cross-sectional secondary moment of the portion 30 is as described above, the difference in the resonance frequency becomes more prominent in the X direction, the Y direction, and the Z direction.

  According to the present example, two of the four connecting portions 30 are arranged in the same straight line with the weight portion 20 sandwiched between them, extending in the X-axis direction, and the other two are Y-axis. It extends in the direction and is arranged in the same straight line with the weight part 20 sandwiched therebetween. By providing symmetry in the X direction and the Y direction in this way, the cross-sectional secondary moments in the X direction and the Y direction are made uniform, and as a result, the resonance frequencies in the X direction and the Y direction can be made uniform. Then, by adjusting the width and length of each connection portion 30, the cross-sectional secondary moment in the Z direction can be made larger than in the X direction and the Y direction.

  FIG. 3 shows a result of simulating the change of the resonance frequency in the X direction, the Y direction, and the Z direction when the length of the connecting portion 30 is changed. Changing only the length of the connecting portion 30 leads to changing the cross-sectional secondary moment of the connecting portion 30. In the drawing, the horizontal axis indicates the length of the connecting portion 30 in the extending direction, and the vertical axis indicates the resonance frequency. As is apparent from the figure, the resonance frequency decreases as the length of the connecting portion 30 is increased in all of the X direction, the Y direction, and the Z direction, but the rate of change thereof varies between the X direction, the Y direction, and the Z direction. It is different. The X direction and the Y direction have substantially the same rate of change, and the rate of change is smaller than that in the Z direction. For this reason, when the length of the connecting portion 30 is shortened, the resonance frequency in the Z direction becomes larger than the resonance frequencies in the X direction and the Y direction. Further, the resonance frequency difference between the X direction and the Y direction and the Z direction also increases. And if the shape of the connection part 30 is made into a wide and short shape, the cross-sectional secondary moment in a Z direction can be enlarged compared with a X direction and a Y direction.

Such a connection part 30 has flexibility, and when the angular velocity is applied to the sensor 100, the weight part 20 is moved by the Coriolis force, and the connection part 30 is twisted as the weight part 20 moves. It is like that. For example, the main portion 33 of the connecting portion 30 has a length in the longitudinal direction set to 0.2 mm to 0.5 mm, and a width (a length in a direction orthogonal to the longitudinal direction) set to 0.04 mm to 0.2 mm. The thickness is set to 5 μm to 20 μm. Thus, by forming the connection part 30 thin, it becomes deformable and flexibility is expressed.

  Moreover, since the connection part 30 has flexibility as above-mentioned, when the acceleration is added to the sensor 100, the weight part 20 will move and the connection part 30 will bend with the movement of the weight part 20. As shown in FIG.

  As shown in FIG. 1, detection portions Rx1 to Rx4, Ry1 to Ry4, Rz1 to Rz4, which are resistance elements, are formed on the upper surface of the connection portion 30 (hereinafter, when these resistance elements are collectively referred to, Represented by the symbol R). The detectors Rx1 to Rx4, Ry1 to Ry4, Rz1 to Rz4 are accelerations in three axes directions (X axis direction, Y axis direction, Z axis direction in the three-dimensional orthogonal coordinate system shown in FIG. 1), and angular velocities around three axes. Is formed at a predetermined position of the connection portion 30 and is connected so as to constitute a bridge circuit.

  Such a detection unit R can be formed, for example, by forming a resistor film by implanting boron into the uppermost layer of the SOI substrate and then patterning the resistor film into a predetermined shape by etching or the like. Thereby, the detection part R which consists of a piezoresistive element can be formed.

  In the case where the detection unit R made of a piezoresistive element is used, the resistance value changes according to deformation caused by bending or twisting of the connection unit 30, and the change in the output voltage based on the change in the resistance value is represented by an electric signal. And is processed by an external IC. Through such a process, the direction and magnitude of the applied acceleration and the direction and magnitude of the angular velocity can be detected.

  A wiring electrode electrically connected from the detection unit R, a pad electrode for taking out to an external IC, and the like are provided on the upper surface of the fixed unit 10, the weight unit 20, and the connection unit 30 via these. To take out the electrical signal.

  These wirings are made of, for example, aluminum, an aluminum alloy, etc., and after depositing these materials by sputtering or the like, the wirings are patterned into a predetermined shape to form upper surfaces of the fixed portion 10, the weight portion 20, and the connection portion 30. It is formed.

  According to the sensor 100 having such a configuration, it is possible to provide a sensor with little variation in detection sensitivity in three axes. The mechanism will be described below.

  The connecting portion 30 is configured to be greatly deformed in the XY direction compared to the Z direction due to its shape. That is, the resonance frequency in the Z direction when the connecting portion 30 is vibrated has a large difference from the values in the X direction and the Y direction, and is extremely larger than the values in the X direction and the Y direction. It has been confirmed that there is no large difference in the resonance frequency between the X direction and the Y direction (see FIG. 3).

  Furthermore, in the sensor 100, the symmetry of the structure can be ensured in the XY direction, but is asymmetric in the Z direction. From this, it is inferred that the resonance frequency in the Z direction has a large difference from the values in the X direction and the Y direction.

  From the above, the resonance frequency of the vibration (driving vibration) that is driven to detect the angular velocity is a value that is far from the other direction only in the Z direction. Here, in the angular velocity sensor, it is known that the detection sensitivity becomes higher as the frequency of the detected vibration and the frequency of the drive vibration are closer. For this reason, in the conventional sensor, only the Z direction differs in sensitivity from the X direction and the Y direction. If the optimum frequency is selected in the X and Y directions, the sensitivity in the Z direction is reduced. Conversely, if the optimum frequency is selected in the Z direction, the sensitivity in the X and Y directions may be reduced. It was.

  On the other hand, according to the sensor 100, the position of the center of gravity of the weight portion 20 is changed according to the difference in the secondary moment of the section between the XY direction and the Z direction of the connection portion 30 and the difference in the resonance frequency associated therewith. Thus, the resonance frequency in the Z direction can be made closer to the X direction and the Y direction. Thereby, it is possible to obtain a sensor with small variations in detection sensitivity in the three axes of XYZ.

  If it demonstrates in detail, the displacement to the XY direction of the weight part 20 is implement | achieved by rotating so that the weight part 20 may twist. That is, the displacement of the weight part 20 in the XY direction is a center point in the plan view of the weight part 20 that is the center of rotation, and the distance from the fulcrum to the gravity center position G1 of the weight part 20 is large. It becomes easier to displace. Here, by positioning the gravity center position G1 of the weight portion 20 above the virtual gravity center position G0 (the side to which the connection portion 30 is connected), the distance from the fulcrum to the gravity center position G1 is reduced, and the XY direction is increased. Displacement is difficult. As a result, the resonance frequency in the X direction and the Y direction is greatly shifted in the higher direction. On the other hand, the displacement of the weight portion 20 in the Z direction is based on the second end 32 that is a connection portion of the connection portion 30 to the fixed portion 10. For this reason, the distance from the 2nd end 32 to the gravity center position G1 of the weight part 20 determines the ease of the displacement in a Z direction. Here, since the difference between the distance from the second end 32 to the gravity center position G1 of the weight portion 20 and the distance from the second end 32 to the virtual gravity center position G0 of the weight portion 20 is not so large, Even if it is changed in the Z direction, the shift amount of the resonance frequency can be suppressed. As described above, when the gravity center position of the weight portion 20 is changed (upward) from the virtual gravity center position G0 to the side to which the connection portion 30 is connected, the propulsive force with respect to the displacement in the XY direction and the displacement in the Z direction. The driving force against That is, the driving force for displacement in the XY direction can be reduced.

  Accordingly, the resonance frequency in the three axes of XYZ can be made closer by combining the weight portion 20 that is difficult to move in the XY direction with the connection portion 30 that is easy to move in the XY direction and difficult to move in the Z direction.

  Moreover, the sensor 100 may be configured such that the fixed portion 10, the weight portion 20, and the connection portion 30 are integrally formed as in the present embodiment. In this case, the sensor has high strength and high reliability.

  As described above, according to the sensor 100 of the present embodiment, a sensor capable of detecting at least the angular velocity can be realized with one component body without increasing the size, and the sensitivity variation in the three-axis directions is small. It can be a sensor of sensitivity. In particular, when the sensor 100 is required to be downsized and the length of the connecting portion 30 in the longitudinal direction cannot be ensured, or the sensor 100 is required to have multiple functions, it is necessary to form various electrical wirings on the connecting portion 30. This is effective when the width of the connecting portion 30 cannot be reduced.

  In the above example, the case where the weight portion 20 is rotated for detecting the angular velocity has been described as an example, but only the connection portion 30 may be periodically vibrated.

(Modification: Sensor shape)
In the example illustrated in FIGS. 1 and 2, the sensor 100 in which the weight portion 20 is held by the connection portion 30 connected to the weight portion 20 at equal intervals has been described as an example, but the present invention is not limited to this example. For example, as shown in FIG. 4, the connection part 30 may be a diaphragm shape.

(Modification: Weight part 20)
In the above-described example, the weight part 20 is composed of a part connected to the connection part 30, a part located below and having a different planar shape, and a connection part connecting them. It is not limited to. For example, as shown in FIG. 5A, a shape in which the cross-sectional area in a plane parallel to the XY plane continuously decreases from the portion connected to the connection portion 30 may be used.

  Further, the cross-sectional area in the plane parallel to the XY plane does not need to be continuously reduced, and may be decreased step by step as shown in FIG. Further, as shown in FIGS. 5A and 5B, the cross-sectional area in the plane parallel to the XY plane does not have to decrease toward the tip, as shown in FIG. 5C. It is good also as a shape which was dented in the connection part 30 side. Furthermore, it is not always necessary to reduce the cross-sectional area in the plane parallel to the XY plane, and as shown in FIG. 5 (d), by providing the accessory portion 25 having a low density without changing the shape of the weight portion 20, You may move the gravity center position G1 to the side connected to the connection part 30. FIG. That is, the density of the weight part 20 may be smaller than the upper side on the lower side than G0.

(Modification: Weight part 20)
In the above-described example, the gravity center position G1 of the weight portion 20 coincides with the center of the weight portion 20 in the XY plane, but is not limited to this example. For example, you may shift from the center of the weight part 20 in XY plane. In this case, the resonance frequency can be adjusted also in the X direction and the Y direction depending on the shape of the weight portion 20. This is particularly effective when the connecting portion 30 holds the weight portion 20 asymmetrically in the X direction and the Y direction. It is also effective when it is desired to make the sensitivity different between the X direction and the Y direction.

(Modification: Other)
In the above example, the weight portion 20 is formed by processing an SOI substrate, but it may be formed by connecting separate bodies. In that case, by using a material having a higher density, it is possible to increase the force generated even at the same acceleration, and to increase the deflection amount of the connecting portion 30 accordingly. Thereby, a sensor with higher sensitivity can be provided.

  Moreover, in the above-mentioned example, although the shape in the top view of the weight part 20 is made into the substantially square shape, it is not limited to this shape. For example, it may be circular, rectangular, or a shape in which an appendage is added to a square corner.

  In the above-described example, the detection unit R has been described using an example in which the detection unit R is formed of a piezoresistor.

  For example, the detection unit R may be an electrode, and the magnitude of deflection / deformation of the connection unit 30 and the direction of deflection / deformation may be detected as an electrical signal based on a change in capacitance. In this case, a fixed part disposed at a distance from the connection part 30 is newly provided, and an electrode facing the detection part R is provided on the fixed part. And what is necessary is just to make an electrode by the side of a fixed part, and the detection part R function as a pair of electrodes, and to measure an electrostatic capacitance.

  Furthermore, in the above-described example, the case where the weight portions 20 are all located below the connection portion 30 has been described as an example, but may be located above.

  In the example described above, the detection unit R is described as being built in the connection unit 30, but may be formed on the connection unit 30. In the former case, the detection part R is flush with the upper surface of the connection part 30 and there is no step, so that the electrical connection of the wiring connected to the detection part R is facilitated. In the latter case, since the detection unit R protrudes, stress due to deformation concentrates, and sensitivity can be increased.

A sensor 100B shown in FIG. 6A was formed, and resonance frequencies in the XY direction and the Z direction were obtained by simulation. The sensor 100B is a diaphragm type, and a weight portion 20B is arranged at the center of a circular diaphragm portion. The weight part 20B has a shape in which two cylinders having different diameters are connected in the Z direction, and a wide part having a large diameter is connected to the diaphragm side. And the part which the weight part 20B is not connected which is a part of diaphragm part functions as the connection part 30B. The shapes of the weight part 20B and the connection part 30B used in the simulation are as follows.

Wide portion of the weight portion 20 has a diameter R1: 200 μm.
Height H1 of wide part of weight part 20: 175 μm
Diameter R2 of the narrow portion of the weight portion 20: 47 μm
Height H2 of the narrow part of the weight part 20: 175 μm
Diaphragm diameter R3 formed by the connecting portion 30 and the weight portion 20: 536 μm
Thickness of connection part 30: 3 μm

  As a comparative example, resonance frequencies in the XY and Z directions of the sensor shown in FIG. 6B were calculated by simulation.

  In the sensor of the comparative example, the weight portion 20 has the same diameter as the wide portion and does not have the narrow portion, and the height thereof is a dimension obtained by combining the wide portion and the narrow portion.

  By adopting such a configuration, the sensor 100B of the embodiment changes the center of gravity of the weight portion 20B upward by 61 μm compared to the sensor of the comparative example.

As a result, it became as follows.
Example Resonant frequency in XY direction: 124.49 kHz
Resonant frequency in the Z direction: 137.54 kHz
Comparative example Resonant frequency in XY direction: 72.461 kHz
Resonant frequency in the Z direction: 110.44 kHz
As described above, in the comparative example, the deviation of the resonance frequency in the XYZ directions is 52%, whereas in the embodiment, it is 7.6%. I confirmed.

DESCRIPTION OF SYMBOLS 10 Fixed part 20 Weight part 30 Connection part 31 1st end 32 2nd end R Detection part 100 Sensor

Claims (4)

The fixed portion, the weight portion arranged at a distance from the fixed portion, the fixed portion and the weight portion are connected to each other, and the weight portion is held. A connecting portion that deforms according to the displacement of the weight portion,
The connecting portion has a shorter length along a virtual line connecting the fixed portion and the center of the weight portion in plan view than the weight portion,
The weight part is a sensor whose center of gravity is located on the side connected to the connection part from half the length in the thickness direction in the thickness direction.   2. The sensor according to claim 1, wherein the connection portion has a cross-sectional secondary moment in a direction parallel to the one plane smaller than a cross-sectional second moment in a thickness direction perpendicular to the one plane.   The weight portion has a cross-sectional area in a plane parallel to the one plane that is smaller on the side away from the connection portion than on the side connected to the connection portion than half the length in the thickness direction. The sensor according to claim 1 or 2.   4. The density according to claim 1, wherein the weight portion has a lower density on a side farther from the connection portion than a side connected to the connection portion from a half of a length in the thickness direction. Sensor.

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