JP2015081822A - Capacitance type sensor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a capacitance type sensor that performs control for shifting the initial position of a movable electrode with respect to the initial position of a fixed electrode and can accurately shift the movable electrode to the initial position.SOLUTION: In the sensor 10, a drive electrode 27 for shifting the position in the Z direction of a main body part 31 including a movable electrode 36 is disposed on a substrate 12. In a movable part 11, when a drive voltage is applied between the drive electrode 27 and a weight part 32, the relative position of the movable electrode 36 to the fixed electrode 25 in the Z direction is shifted by the electrostatic force. Then, the initial position of the movable part 11 shifted by the electrostatic force becomes a position at which the movement of the weight part 32 is regulated by a stopper 29 disposed on the substrate 12.

Description

  The technology disclosed in the present application relates to a capacitive sensor configured as MEMS (Micro Electro Mechanical Systems).

  Conventionally, some physical quantity sensors manufactured using MEMS technology use capacitance. For example, there is a substrate and a movable portion that is provided so as to be able to swing away from the substrate, and the movable portion is connected to an anchor standing on the substrate via a beam (for example, Patent Documents). 1). In the sensor disclosed in Patent Document 1, the beam is configured to be elastically deformable, and a movable part connected to one end of the beam in the Z direction according to the acceleration acting in the Z direction perpendicular to the plane of the substrate. Displace. The movable portion is integrally formed with comb-like movable electrodes, and a fixed electrode fixed to the substrate is formed between the movable electrodes. In the sensor, a capacitor is composed of each of a movable electrode and a fixed electrode facing each other in a plane direction parallel to the plane of the substrate. In the sensor, the facing area between the movable electrode and the fixed electrode varies according to the displacement of the movable part in the Z direction, and the acceleration is detected from the amount of change in the electrostatic capacity due to the variation in the facing area.

  Further, the sensor disclosed in Patent Document 1 has a plurality of protrusions penetrating the substrate. This protrusion is used as a drive electrode for shifting the initial positions of the movable part and the movable electrode in order to distinguish the direction of acceleration in the Z direction. Specifically, in the above-described sensor, when the movable electrode and the fixed electrode are in the same initial position in the Z direction, the movable electrode moves in either the + Z direction where the movable electrode is separated from the substrate or the −Z direction which is closer to the substrate. In this case, the capacitance value of the capacitor composed of the fixed electrode and the movable electrode is similarly reduced. That is, at this initial position, it cannot be determined whether the acceleration is applied in the + Z direction or the −Z direction in the process of detecting the acceleration from the change in capacitance. Therefore, in the sensor disclosed in Patent Document 1, when a driving voltage is applied between the protrusion and the movable part, the initial position of the movable electrode is displaced in the −Z direction by the electrostatic force compared to the fixed electrode. It has a configuration. The sensor detects the increase in the capacitance of the movable electrode and the fixed electrode as an acceleration applied in the + Z direction, with the position shifted in the Z direction as the initial position of the movable electrode, and decreases the capacitance. Is detected as an acceleration applied in the −Z direction.

JP 2012-42228 A (paragraphs 0077 to 0098, FIGS. 15 to 19)

  However, the movable part and the movable electrode of the sensor described above have an electrostatic force generated between the movable part and the protruding part, an elastic force acting on the movable part according to the spring constant of the beam, and a gap between the movable electrode and the fixed electrode. The position where a plurality of forces such as the generated electrostatic force are balanced is the initial position. The initial position of the movable part is determined in a state where the entire movable part floats at a position where forces are balanced while being displaced along the −Z direction. On the other hand, in this type of sensor, there may be variations in the accuracy of the manufacturing process, for example, the thickness of the beam and the thickness of the movable part that occur in etching that forms the beam and the movable part. For this reason, the control for applying the driving voltage between the movable part and the projecting part to displace the movable part to a desired initial position can be controlled with high accuracy because the condition and processing contents for balancing a plurality of forces are complicated. It becomes difficult. As a result, in this sensor, the detection accuracy is lowered due to a shift in the initial position of the movable electrode that is displaced by applying the drive voltage. Alternatively, the sensor is unloaded after a physical quantity (for example, acceleration) is applied to the movable part, and when the movable part returns to the initial position again, the detection accuracy is lowered due to a shift in the position of the movable electrode. It becomes.

  The technology disclosed in the present application has been proposed in view of the above problems. Provided is a capacitance type sensor that performs control for shifting an initial position of a movable electrode with respect to an initial position of a fixed electrode, and is capable of accurately shifting the movable electrode to the initial position. With the goal.

  The capacitive sensor according to the technology disclosed in the present application is provided with a substrate, a movable part that is provided so as to be able to swing freely from the substrate, a movable electrode provided on the movable part, and a fixed to the substrate. The fixed area where the opposed area to the movable electrode facing away from each other in the plane direction parallel to the plane of the substrate varies depending on the application of a physical quantity to the movable part, and the capacitance with the movable electrode varies according to the variation of the opposed area A drive voltage is applied between the electrode and the movable part, and the position of the movable part in a direction perpendicular to the plane of the substrate is displaced by electrostatic force, and the relative position of the movable electrode with respect to the fixed electrode is shifted to electrostatically A drive electrode that fluctuates the capacity; and a restricting portion that restricts movement of the restricted portion of the movable portion that is displaced by electrostatic force and holds the movable portion at an initial position.

  In this capacitance type sensor, the amount of change in the capacitance of a capacitor composed of a movable electrode provided in a movable part provided to be swingable with respect to the substrate and a fixed electrode provided fixed to the substrate is obtained. By outputting, a physical quantity (for example, acceleration) applied to the movable part is detected. Further, the sensor is provided with a drive electrode for shifting the position of the movable electrode. When a drive voltage is applied between the movable part and the drive electrode, the relative position of the movable electrode with respect to the fixed electrode is shifted due to electrostatic force. And the movable part displaced by electrostatic force becomes the initial position at the position where the movement of the regulated part is regulated by the regulating part, and the movable part is held in that state. In this configuration, the initial position of the movable part where the restricted part is held by the restricting part is uniquely determined by the positions and shapes of the restricting part and the restricted part. As a result, the sensor can apply a drive voltage between the movable part and the drive electrode to accurately shift the movable part to a desired initial position, and prevent the initial position of the movable electrode included in the movable part from being shifted. By doing so, it becomes possible to improve the detection accuracy of the physical quantity. The sensor can also improve detection accuracy by returning the movable electrode to the correct initial position when no load is applied after the physical quantity is applied to the movable part and the movable part returns to the initial position again. .

  In the capacitive sensor according to the technology disclosed in the present application, the substrate includes a core substrate and an insulating layer formed on the core substrate, and the restricting portion is in a direction perpendicular to the plane of the substrate. It is good also as a structure provided on the insulating layer used as the position facing a to-be-controlled part.

  In the capacitance type sensor, a regulating portion provided on the insulating layer and electrically insulated contacts the regulated portion of the movable portion to which the drive voltage is applied to regulate the movement. Here, in the sensor configured to apply the driving voltage to the restricting portion, there is a possibility that a short circuit occurs when the restricting portion comes into contact with the movable portion or the restricted portion, or sticking due to electrostatic force occurs. On the other hand, the sensor can detect a desired physical quantity in a state where the regulated portion is suitably held at the initial position by regulating the movement by bringing the regulated regulating portion into contact with the regulated portion. Become.

  In the capacitance-type sensor according to the technology disclosed in the present application, the movable part is connected to the main body part provided with the movable electrode and the fixed part provided fixed to the substrate, and the main body part is used as the fixed part. On the other hand, the first elastic member which is held so as to be swingable in a direction perpendicular to the plane of the substrate, and the regulated portion are connected to the main body, and the regulated portion is connected to the plane of the substrate with respect to the main body. And a second elastic member that is held so as to be swingable in a vertical direction.

  In the capacitance type sensor, the main body portion provided with the movable electrode is connected to the fixed portion provided by being fixed to the substrate by the first elastic member, so that the main body portion is perpendicular to the plane of the substrate. It is held so that it can swing in any direction. Further, the regulated portion is held to be swingable in a direction perpendicular to the plane of the substrate by being connected to the main body portion by the second elastic member. In the state where the driving voltage is applied between the movable part and the driving electrode, the sensor can hold the regulated part to which the electrostatic force is applied, with respect to the regulating part. For this reason, in the initial state in which the physical quantity is detected, the sensor can be in a state where the restricted portion is fixed in addition to the fixed portion. Then, when a desired physical quantity is applied to the main body portion of the movable portion, the first and second elastic members connected to the fixed portion and the restricted portion are directed in a direction perpendicular to the plane of the substrate. Swing. Therefore, the sensor unambiguously determines the initial position of the movable electrode and starts detection of the physical quantity, and then the main body part and the movable electrode that swing when the physical quantity is applied are connected between the fixed part and the regulated part. The detection accuracy can be improved by supporting the two fulcrums and swinging them stably.

  In the capacitive sensor according to the technology disclosed in the present application, the main body is formed in a plate shape having a rectangular shape when viewed from a direction perpendicular to the plane of the substrate, and is short on one end side in the longitudinal direction. The first elastic member is connected to the side, the second elastic member is connected to the short side on the other end side in the longitudinal direction, and the drive electrode is positioned opposite the regulated portion in the direction perpendicular to the plane of the substrate The driving voltage may be applied between the substrate and the regulated portion.

  In the capacitance type sensor, the main body is formed in a rectangular plate shape, the first elastic member is connected to the short side on one end side in the longitudinal direction, and the second elastic member is connected to the short side on the other end side. Is done. Therefore, the fixed portion and the restricted portion connected to each of the first and second elastic members can be provided at positions opposite to each other with respect to the longitudinal direction of the main body portion. The regulated portion is displaced by an electrostatic force when the drive electrode is applied between the regulated electrode and the movement of the regulated portion is regulated by a regulating portion provided at a position facing the substrate. The regulated portion is held by the regulating portion with the electrostatic force acting. In this initial position, the movable part including the main body part and the regulated part is held in an inclined state with respect to the longitudinal direction from the fixed part side to the regulated part side in the longitudinal direction. Capacitance of the capacitor consisting of the movable electrode and fixed electrode of the main body is the value at the initial position as the value of the capacitance decreases as the movable electrode tilts and the area facing the fixed electrode decreases. Is determined. In such a configuration, the initial positions of the movable electrode and the movable part can be adjusted by the length along the longitudinal direction of the main body part and the first and second elastic members. For example, the movable portion can reduce the inclination of the entire movable portion at the initial position as the length along the longitudinal direction of the main body portion is increased. Therefore, the amount of change in the capacitance between the movable electrode displaced to the initial position and the fixed electrode fixed can be reduced by increasing the length of the main body in the longitudinal direction. It is possible to make adjustment to reduce the size.

  In the capacitive sensor according to the technology disclosed in the present application, at least one set of main body portions provided at each position symmetrical to the regulated portion is provided along a plane direction parallel to the plane of the substrate. The main body part of the set is provided at a position where the movable electrode of one main body part is symmetric in the plane direction with respect to the position where the movable electrode of the other main body part is provided and the regulated part. May be configured to be opposed to each movable electrode of a set of main body portions.

  In the capacitance type sensor, a pair of main body portions are provided at positions symmetrical with respect to the regulated portion. One set of main body portions is provided at a position where the movable electrode of one main body portion is symmetrical in the plane direction with respect to the position where the movable electrode of the other main body portion is provided and the regulated portion. Since the movable electrode of the main body is provided at a position that is symmetric in the planar direction with respect to the regulated portion, a set of modes in which the movable electrode fluctuates when a physical quantity is applied in a desired detection direction. It becomes possible to make it a mutually similar aspect in a main-body part. As a result, the sensor detects, for example, one set of differences in capacitance variation caused by the main body rotating in a direction different from the physical quantity detection direction with respect to the capacitance of each movable electrode and fixed electrode. This can be reduced by calculating the average value of the amount of change in the mutual capacitance of the main body portions, and the acceleration detection accuracy can be improved.

  According to the technique disclosed in the present application, it is a capacitive sensor that performs control to shift the initial position of the movable electrode with respect to the initial position of the fixed electrode, and the movable electrode can be accurately shifted to the initial position. An electrostatic capacitance type sensor can be provided.

It is a top view which shows schematic structure of the electrostatic capacitance type acceleration sensor of 1st Example. It is the sectional view on the AA line of FIG. It is a schematic diagram for demonstrating operation | movement of the sensor shown in FIG. It is a mimetic diagram of a sensor in the state where a movable part became an initial position. It is a schematic diagram of a sensor to which acceleration is applied in the −Z direction. It is a schematic diagram of a sensor to which acceleration is applied in the + Z direction. It is a top view which shows schematic structure of the electrostatic capacitance type acceleration sensor of 2nd Example. It is a top view which shows schematic structure of the capacitive acceleration sensor of 3rd Example. It is a top view which shows schematic structure of the electrostatic capacitance type angular velocity sensor of 4th Example. It is a top view which shows schematic structure of the capacitive acceleration sensor of 5th Example. FIG. 10 is a cross-sectional view taken along line B-B in FIG.

(First embodiment)
Hereinafter, an embodiment (first embodiment) embodying the present invention will be described with reference to the accompanying drawings. Note that, for convenience of explanation, the accompanying drawings include portions that are illustrated differently from actual dimensions and scales.
FIG. 1 is a plan view showing a schematic configuration of a capacitance type acceleration sensor according to the present embodiment manufactured using a MEMS (Micro Electro Mechanical Systems) technique. As shown in FIG. 1, a capacitive acceleration sensor (hereinafter referred to as “sensor”) 10 includes a movable portion 11 and a substrate 12 (see FIG. 2). In the sensor 10, a frame portion 13 is formed so as to surround the outer edge of the movable portion 11. The frame portion 13 is formed in a rectangular frame shape when viewed from a direction perpendicular to the substrate plane of the substrate 12, and the inner wall is separated from the outer peripheral portion of the movable portion 11 provided inside. In the following description, as indicated by an arrow in FIG. 1, the direction along the longitudinal direction of the frame portion 13 is the X direction, and the direction perpendicular to the X direction and along the short direction of the frame portion 13 is Y. The direction perpendicular to both the X direction and the Y direction is referred to as the Z direction and will be described.

  FIG. 2 is a cross-sectional view taken along line AA in FIG. As shown in FIG. 2, the frame portion 13 has a base end portion in the Z direction formed integrally with the substrate 12 and extends from the substrate 12 along the Z direction. The front end surface 13A in the Z direction of the frame portion 13 has the same position in the Z direction as the upper surface 11A (upper surface in FIG. 2) of the movable portion 11. The substrate 12 has an insulating layer 22 formed so as to cover the upper surface of the flat core substrate 21 in the Z direction. Electrodes 23 and 24 are formed on the insulating layer 22. The electrode 23 is formed on the substrate 12 at both ends in the Y direction on one end side in the X direction (right side in FIG. 2), and an anchor 14 is formed on each upper surface of the electrode 23. The anchor 14 has a rectangular parallelepiped shape standing on the substrate 12 and extending in the Z direction. The anchor 14 is formed with a through hole 14 A in which a conductive material is embedded, and the through hole 14 A is electrically connected to the electrode 23.

  As shown in FIGS. 1 and 2, the movable portion 11 includes a main body portion 31 and a weight portion 32. The main body 31 is formed in a plate shape having a long side that is substantially rectangular in plan view along the X direction. In the main body 31, the length of the short side along the Y direction is substantially the same as the distance between the pair of anchors 14. The main body 31 is mechanically connected to each of the anchors 14 via a first spring 34. The movable part 11 including the main body part 31 is electrically connected to the electrode 23 via the first spring 34 and the through hole 14 </ b> A of the anchor 14. The movable part 11 is connected to an external circuit by wiring (not shown) connected to the electrode 23. The main body portion 31 is formed with a first connecting portion 35 protruding in the X direction at an end portion on the anchor 14 side in the X direction. The first connection part 35 is formed in the center part of the short side along the Y direction of the main body part 31. Each of the first springs 34 has a meandering shape in plan view, and has a shape extending in the X direction while meandering in the Y direction. The first spring 34 has a fixed end 34 </ b> A on one end side fixed to a side surface in the X direction of the anchor 14, and a movable end 34 </ b> B on the other end side connected to a side surface in the Y direction of the first connection portion 35. The first spring 34 has a flexibility in two directions, the X direction and the Z direction, and has a structure in which expansion and contraction is restricted by increasing rigidity in the Y direction. As shown in FIG. 2, the movable part 11 including the main body part 31 is lifted above the substrate 12 by being supported by the anchor 14 fixed to the substrate 12 via the first spring 34. Is held by. In the sensor 10 of the first embodiment, when acceleration is applied in the Z direction, the first spring 34 is elastically deformed and the main body 31 is displaced in the Z direction.

  The sensor 10 is provided with a plurality (seven in this embodiment) of fixed electrodes 25. The fixed electrode 25 is formed in a substantially rectangular plate shape whose main surface is along the Z direction, and its long side is formed along the X direction. The fixed electrodes 25 are arranged side by side so that their main surfaces face each other in the Y direction. The fixed electrode 25 is provided with a through hole 25A on one end side in the X direction (right side in the drawing) and is electrically connected to the electrode 24 formed on the substrate 12. The fixed electrode 25 is connected to an external circuit by wiring (not shown) connected to the electrode 24. Each of the plurality of electrodes 24 is formed at equal intervals along the Y direction at a substantially central portion in the X direction of the substrate 12. Accordingly, each of the fixed electrodes 25 extends from the central portion of the substrate 12 where the through hole 25A is connected to the electrode 24 toward one side in the X direction (left side in FIG. 1). Further, the fixed electrode 25 is formed so that a portion excluding an end portion where the through hole 25 </ b> A is provided is separated from the substrate 12.

  The main body 31 is integrally formed with a movable electrode 36 that faces the fixed electrode 25. The movable electrode 36 includes a frame-shaped electrode portion 36A (mainly a portion surrounded by a one-dot chain line in FIG. 1) formed so as to surround the outer peripheral portion of the fixed electrode 25 in a plan view shown in FIG. And a flat plate electrode portion 36B provided between the fixed electrodes 25 arranged side by side. The frame-shaped electrode portion 36 </ b> A has a rectangular frame shape integrally formed with the main body portion 31 and is separated from each of the fixed electrodes 25. The plate electrode portion 36B extends from the main body portion 31 so as to face the fixed electrode 25 in the Y direction, has a main surface formed in a substantially rectangular plate shape along the Z direction, and a long side along the X direction. Each flat plate electrode portion 36B is integrally formed with the frame electrode portion 36A at both ends in the X direction. In the fixed electrode 25, the length L1 (see FIG. 2) along the Z direction of the portion excluding the end provided with the through hole 25A is the length along the Z direction of the frame-like electrode portion 36A and the plate electrode portion 36B. It is formed substantially the same. Further, the fixed electrode 25 is formed with a length L2 along the X direction shorter than the frame-shaped electrode portion 36A and the plate electrode portion 36B, and a gap 39 is provided between the fixed electrode 25 and the frame-shaped electrode portion 36A in the X direction. It is fixed. The fixed electrode 25 is opposed to each of the frame-shaped electrode portion 36A and the plate electrode portion 36B in the Y direction with a gap having a predetermined width.

  The movable portion 11 is connected to the end portion of the main body portion 31 on the opposite side to the anchor 14 in the X direction via the weight portion 32 and the second spring 41. The weight portion 32 is electrically connected to the electrode 23 connected to the through hole 14 </ b> A via the second spring 41 and the main body portion 31. The weight portion 32 is formed in a plate shape having a long side with a substantially rectangular shape in plan view along the Y direction. The weight portion 32 has a long side length along the Y direction that is longer than a short side length along the Y direction of the main body portion 31. The main body portion 31 is formed with a second connection portion 42 that protrudes in the X direction at an end portion of the weight portion 32 side opposite to the first connection portion 35 in the X direction. The second connection part 42 is formed in the center part of the short side along the Y direction of the main body part 31. Each of the second springs 41 has a meandering shape in plan view, and has a shape extending in the X direction while meandering in the Y direction, like the first spring 34. The second spring 41 has a first end portion 41A on one end side fixed to a side surface in the X direction of the weight portion 32, and a second end portion 41B on the other end side connected to a side surface in the Y direction of the second connection portion 42. ing. Similar to the first spring 34, the second spring 41 has flexibility in two directions, the X direction and the Z direction, and has a structure in which expansion and contraction is restricted by increasing rigidity in the Y direction. For this reason, the weight part 32 is supported via the second spring 41 with respect to the main body part 31 and is configured to be displaceable in the Z direction.

  The substrate 12 is provided with a drive electrode 27 that displaces the weight portion 32 in the Z direction. The drive electrode 27 is formed in a substantially rectangular shape in plan view along the Y direction, and the drive electrode 27 is formed so as to spread on the upper surface of the insulating layer 22 so as to face the weight portion 32 in the Z direction. The drive electrode 27 displaces the position of the movable portion 11 in the Z direction by electrostatic force when a drive voltage is applied between the movable portion 11 and the movable portion 11 including the weight portion 32. Further, the substrate 12 is provided with a stopper 29 for preventing the weight portion 32 displaced in the Z direction from colliding with the drive electrode 27. For example, the stopper 29 is formed integrally with the insulating layer 22 on both sides in the X direction of the drive electrode 27 and is electrically insulated. A plurality (three in the illustrated example) of the stoppers 29 are provided on one side of the drive electrode 27 in the X direction. Note that the shape, number, and position of the stopper 29 shown in FIGS. 1 and 2 are examples, and may be appropriately changed according to the configuration of the sensor 10. Each of the stoppers 29 is provided with a gap having a predetermined width from the drive electrode 27 in the X direction. The stopper 29 is formed to have a height in the Z direction larger than that of the drive electrode 27. Accordingly, the gap between the stopper 29 and the weight portion 32 along the Z direction is narrower than the gap between the drive electrode 27 and the weight portion 32. For this reason, the weight part 32 collides with the stopper 29 before colliding with the drive electrode 27 when displaced along the Z direction toward the substrate 12 side.

  In the sensor 10 having the above-described configuration, the movable electrode 11 of the movable part 11 and the fixed electrode 25 of the substrate 12 constitute a parallel plate capacitor. In this parallel plate capacitor, when the movable portion 11 fluctuates according to the acceleration in the Z direction acting on the sensor 10, the facing area between each of the fixed electrodes 25 and the movable electrode 36 fluctuates, and the capacitance changes. The sensor 10 measures the capacitance of the parallel plate capacitor, which changes with the displacement of the movable electrode 36 in the Z direction, using an external circuit. The external circuit of the sensor 10 detects the acceleration in the Z direction by, for example, converting and amplifying the change in capacitance into an electric signal by CV conversion and extracting it as an acceleration signal. At this time, since the first and second springs 34 and 41 have a structure with increased rigidity in the Y direction, the sensor 10 detects the acceleration acting in the Z direction, while the Y of the movable portion 11 is detected. Since the variation in the direction is suppressed, the sensitivity of the other axis in the Y direction can be suppressed, and the detection accuracy can be improved. In addition, since the sensor 10 is suppressed from moving in the Y direction of the movable portion 11, it is possible to prevent the movable electrode 36 and the fixed electrode 25 from colliding with each other and causing a short circuit.

  As a method for manufacturing the sensor 10, for example, an insulating layer 22 (for example, silicon nitride), electrodes 23 and 24, wirings (not shown), and the like are formed on the core substrate 21 of the substrate 12. On the other hand, a low-resistance electrode layer (for example, polysilicon) is formed through a sacrificial layer (for example, silicon dioxide). The electrode layer is etched to form the main body 31, the weight 32, the first and second springs 34 and 41, the anchor 14, and the like. The sacrificial layer is etched by introducing an etching solution through an etching hole (not shown).

Next, the setting of the initial position of the movable part 11 will be described.
FIG. 3 is a schematic diagram of the sensor 10 shown in FIG. In the following description, as shown in FIG. 3, the direction in which the movable part 11 moves away from the substrate 12 is referred to as + Z direction, and the direction in which the movable part 11 approaches the substrate 12 is referred to as −Z direction. In the sensor 10, when the acceleration in the Z direction is not applied, the position of the movable electrode 36 of the movable portion 11 and the position of the fixed electrode 25 in the Z direction are the same. In the sensor 10, when acceleration is applied in the Z direction in this state, the fixed electrode 25 fixed to the substrate 12 is not displaced, while the main body 31 is held by the anchor 14 via the first spring 34. The movable electrode 36 is relatively displaced in the Z direction. At this time, the sensor 10 detects the acceleration in the Z direction by detecting that the facing area between the fixed electrode 25 and the movable electrode 36 decreases and the capacitance value decreases. However, as shown in FIG. 3, the sensor 10 may be applied with acceleration in either the + Z direction or the −Z direction when the movable electrode 36 and the fixed electrode 25 are in the same position in the Z direction. The capacitance value will decrease. That is, the sensor 10 cannot determine the direction of acceleration (+ Z direction or −Z direction) based on the amount of change in capacitance. Therefore, the sensor 10 of the present embodiment changes the position of the movable portion 11 in order to be able to determine the direction of the applied acceleration prior to detecting the acceleration.

  FIG. 4 shows the sensor 10 in a state where the movable part 11 is in the initial position. As shown in FIG. 4, the sensor 10 is configured so that, for example, a driving voltage is applied between the driving electrode 27 and the weight portion 32 in a state where a voltage is applied between the movable electrode 36 and the fixed electrode 25. As a result, the entire movable portion 11 is displaced in the −Z direction. As an example, the electric potential of the weight part 32 and the main-body part 31 is 7V. The potential of the drive electrode 27 is 4V. The potential of the fixed electrode 25 is 0V. Here, the weight portion 32 and the main body portion 31 act on the main body portion 31 in accordance with the electrostatic force generated between the weight portion 32 and the drive electrode 27 and the spring constant of the first spring 34 in the state where the stopper 29 is not provided. Displacement in the −Z direction to a position where a plurality of forces such as an elastic force and an electrostatic force generated between the movable electrode 36 and the fixed electrode 25 are balanced. For this reason, the control for moving the weight portion 32 and the main body portion 31 to the desired initial position along the −Z direction makes it difficult to accurately control conditions and processing contents for balancing a plurality of forces. Therefore, in the sensor 10 of the present embodiment, the movement of the weight portion 32 that is displaced in the −Z direction when a driving voltage is applied is restricted by the stopper 29 and the main body portion 31 is set to the initial position.

  As shown in FIG. 4, the movement of the movable portion 11 is restricted by the stopper 29 coming into contact with the weight portion 32 that is displaced in the −Z direction. Since the weight portion 32 is in contact with the stopper 29 while the electrostatic force directed in the −Z direction is applied, the weight portion 32 is pressed against the stopper 29 by the electrostatic force and does not move in the + Z direction. The movable portion 11 is held in an inclined state so that the distance from the substrate 12 becomes shorter from the anchor 14 side toward the weight portion 32 side in the X direction. The main body 31 and the movable electrode 36 of the movable part 11 are thus held at the initial position. For example, the initial positions of the movable electrode 36 and the main body 31 are set at a height that is ½ of the gap between the main body 31 and the substrate 12 in the state shown in FIG. The capacitance of the capacitor composed of the movable electrode 36 and the fixed electrode 25 decreases as the movable electrode 36 moves in the −Z direction and the area facing the fixed electrode 25 decreases, and the value at the initial position is reduced. It is determined.

  The initial position of the movable electrode 36 can be set based on various conditions. For example, the initial position of the movable electrode 36 can be adjusted based on the height of the stopper 29, the distance (gap) in the Z direction between the movable portion 11 and the substrate 12, and the spring constants of the first and second springs 34 and 41. is there. The initial position of the movable electrode 36 can be adjusted by the length of the main body 31 and the first and second springs 34 and 41 along the X direction. For example, as the entire movable portion 11 is increased in length along the X direction of the main body portion 31, the position where the weight portion 32 and the stopper 29 abut is further away from the anchor 14 along the X direction. The angle tilted in the −Z direction with respect to the X direction at the initial position becomes small. For this reason, the angle at which the movable electrode 36 is inclined in the −Z direction at the initial position is reduced by increasing the length of the main body portion 31 in the X direction. As a result, the amount of change in the capacitance between the movable electrode 36 and the fixed electrode 25 that is displaced to the initial position increases the length of the main body 31 in the X direction so that the movable electrode 36 and the main body 31 are − The angle of tilting in the Z direction is reduced, and adjustment to reduce the amount of change is possible. The capacitance value at the initial position can also be changed by changing the length along the X direction of other members (the first and second springs 34 and 41, the weight portion 32, etc.) other than the main body portion 31. Similar adjustments are possible.

  The sensor 10 can also adjust the capacitance value at the initial position by changing the positions and shapes of the movable electrode 36 and the fixed electrode 25. For example, the main body 31 and the movable electrode 36 at the initial position shown in FIG. 4 are held in an inclined state from the anchor 14 side to the weight portion 32 side in the X direction. Therefore, when the position where the movable electrode 36 and the fixed electrode 25 are provided along the X direction from the anchor 14 side toward the weight portion 32 side is changed, the facing area is reduced and the initial position is reduced. The capacitance value decreases. Similarly, when the position where the movable electrode 36 and the fixed electrode 25 are provided from the weight portion 32 side toward the anchor 14 side is changed, the facing area increases and the capacitance value at the initial position increases. Accordingly, the sensor 10 adjusts the value of the capacitance at the initial position by changing the positions of the movable electrode 36 and the fixed electrode 25.

  The sensor 10 according to the present embodiment can adjust the initial position of the movable electrode 36 and the capacitance value based on the above-described conditions, and in addition to the drive electrode 27 and the weight portion by providing the stopper 29. As a driving voltage to be applied to 32, a value can be set on condition that the weight portion 32 comes into contact with the stopper 29. In other words, the voltage value of the drive voltage that determines the initial position is allowed as long as it is equal to or higher than the voltage value at which the weight portion 32 contacts the stopper 29. Thereby, voltage control for moving the movable portion 11 including the weight portion 32 and the main body portion 31 to the desired initial position along the −Z direction becomes easy and can be controlled with high accuracy.

  In the state illustrated in FIG. 4, when acceleration is applied in the −Z direction, the sensor unit 10 is displaced from the initial position in the −Z direction as illustrated in FIG. 5. In this case, the capacitance value between the fixed electrode 25 and the movable electrode 36 is smaller than the value at the initial position because the facing area between the fixed electrode 25 and the movable electrode 36 is reduced. The main body 31 tends to be displaced in the −Z direction relative to the anchor 14 connected via the first spring 34. The main body 31 is connected to the weight 32 pressed against the stopper 29 by the electrostatic force of the driving voltage via the second spring 41, and is relatively relative to the weight 32 in the −Z direction. Try to displace. That is, the weight portion 32 functions as an apparently fixed portion with respect to the main body portion 31 like the anchor 14 by fixing the position in the Z direction by the electrostatic force with the drive electrode 27 and the stopper 29. As a result, the main body 31 is supported on the two fulcrums of the anchor 14 and the weight 32 on both sides in the X direction, so that the swinging in the direction other than the Z direction for detecting acceleration is reduced and the other axis sensitivity is improved. It can be suppressed and detection accuracy can be improved.

  On the other hand, when acceleration is applied in the + Z direction in the state shown in FIG. 4, the main body 31 is displaced in the + Z direction as shown in FIG. In this case, the capacitance value between the fixed electrode 25 and the movable electrode 36 increases as compared with the value at the initial position because the opposed area between the fixed electrode 25 and the movable electrode 36 becomes large. In this way, the sensor 10 increases in capacitance when acceleration is applied in the + Z direction (see FIG. 6), and decreases in capacitance when acceleration is applied in the −Z direction (see FIG. 5). ). For this reason, the sensor 10 detects the acceleration by determining the + Z direction or the −Z direction from the increase / decrease of the capacitance value even when the acceleration in the same direction is applied in the opposite direction in the Z direction. It becomes possible.

  In the sensor 10 of the present embodiment, the first spring 34 has flexibility in the X direction, and the movable electrode 36 may be displaced in the X direction as the movable portion 11 is displaced. Since the weight portion 32 is fixedly held with respect to the stopper 29 by the force, the displacement of the movable electrode 36 in the X direction is suppressed. Further, since the fixed electrode 25 is fixed with a gap 39 (see FIG. 1) between the fixed electrode 25 and the frame-shaped electrode portion 36A in the X direction, the sensor 10 is fixed as the movable electrode 36 is displaced in the X direction. The collision between the electrode 25 and the frame-shaped electrode portion 36A is prevented.

As described above, according to the first embodiment described above, the following effects are obtained.
<Effect 1> In the sensor 10, the drive electrode 27 for shifting the position in the Z direction of the main body 31 including the movable electrode 36 is provided on the substrate 12. When a driving voltage is applied between the driving electrode 27 and the weight portion 32, the movable portion 11 is displaced in the Z-direction relative to the fixed electrode 25 by the electrostatic force due to electrostatic force. The movable portion 11 that is displaced by the electrostatic force has an initial position at which the movement of the weight portion 32 is restricted by the stopper 29. In this configuration, in the movable portion 11, the initial position where the weight portion 32 is held by the stopper 29 is uniquely determined by the positions, shapes, and the like of the stopper 29 and the weight portion 32. The sensor 10 can set a driving voltage to be applied to the driving electrode 27 and the weight portion 32 as a condition that causes the weight portion 32 to contact the stopper 29. In other words, the voltage value of the drive voltage that determines the initial position is allowed as long as it is equal to or higher than the voltage value at which the weight portion 32 contacts the stopper 29. Thereby, voltage control for moving the movable portion 11 including the weight portion 32 and the main body portion 31 to the desired initial position along the −Z direction becomes easy and can be controlled with high accuracy. As a result, the sensor 10 can improve the acceleration detection accuracy by preventing the displacement of the initial position of the movable electrode 36. The sensor 10 is in a state in which the weight 32 and the anchor 14 are fixed when the movable portion 11 is unloaded after acceleration is applied to the movable portion 11 and the movable portion 11 returns to the initial position again. It is possible to improve detection accuracy also by returning to the correct initial position.

<Effect 2> Each of the stoppers 29 is formed integrally with the insulating layer 22 on both sides in the X direction of the drive electrode 27 and is electrically insulated. Here, in the sensor disclosed in the above-mentioned patent document, since a driving voltage is applied to the stopper (protrusion), if the stopper contacts the movable portion (weight), a short circuit occurs or sticking due to electrostatic force occurs. There is a possibility that it will occur, and it is difficult to detect acceleration in a state where the stopper 29 is in contact with the movable portion 11 as in this embodiment. On the other hand, in the sensor 10 of the present embodiment, the insulated stopper 29 is brought into contact with the weight portion 32 (movable portion 11) to restrict the movement, so that the weight portion 32 is suitably held at the initial position. Desired acceleration can be detected.

<Effect 3> In the sensor 10, when the acceleration is applied in the -Z direction, the main body 31 is displaced in the -Z direction from the initial position (see FIG. 5). At this time, the body portion 31 is in a state where the weight portion 32 connected via the second spring 41 is pressed against the stopper 29 by electrostatic force with the drive electrode 27. Accordingly, the weight portion 32 functions as an apparently fixed portion with respect to the main body portion 31 similarly to the anchor 14 by fixing the position in the Z direction. As a result, the main body 31 is supported on the two fulcrums of the anchor 14 and the weight 32 on both sides in the X direction, so that the swinging in the direction other than the Z direction for detecting acceleration is reduced and the other axis sensitivity is improved. It can be suppressed and detection accuracy can be improved.

<Effect 4> In the sensor 10, the main body 31 is formed in a rectangular plate shape, and the anchor 14 is connected to the short side on the one end side in the X direction, which is the longitudinal direction, via the first spring 34, and the other end side. A weight portion 32 is connected to the short side of the first via a second spring 41. In such a configuration, for example, the movable portion 11 moves away from the anchor 14 along the X direction at a position where the weight portion 32 and the stopper 29 abut as the length along the X direction of the main body portion 31 increases. The angle tilted in the −Z direction with respect to the X direction at the initial position can be reduced. Accordingly, the amount of change in the capacitance between the movable electrode 36 that is displaced to the initial position and the fixed electrode 25 that is fixed is increased by increasing the length of the main body 31 in the X direction. As a result, the angle to be tilted becomes smaller, and adjustment to reduce the change amount becomes possible.

(Second embodiment)
Next, a second embodiment will be described with reference to FIG. In addition, the same code | symbol is attached | subjected about the thing similar to 1st Example, and the description is abbreviate | omitted suitably. The sensor 10A according to the second embodiment is different from the first embodiment in the configuration of the first spring 51 and the second spring 52. Specifically, each of the first springs 51 has a meandering shape in plan view, and has a shape extending in the Y direction while meandering in the X direction. The first spring 51 has a fixed end 51 </ b> A on one end side fixed to a side surface in the X direction of the anchor 14, and a movable end 51 </ b> B on the other end side connected to a side surface in the Y direction of the first connection portion 35. Each of the second springs 52 has a shape extending in the Y direction while meandering in the X direction, like the first spring 51. The second spring 52 has a first end portion 52A on one end side connected to a side surface in the X direction of the weight portion 32, and a second end portion 52B on the other end side connected to a side surface in the Y direction of the second connection portion 42. ing. The first and second springs 51 and 52 have flexibility in two directions, Y direction and Z direction, and have a structure in which expansion and contraction is restricted by increasing rigidity in the X direction. Further, the fixed electrode 25 is formed in a substantially rectangular plate shape whose main surface is along the Z direction, and unlike the first embodiment, the long side is formed along the Y direction. Further, the frame-like electrode portion 36A and the plate electrode portion 36B are provided so as to face the fixed electrode 25 in the X direction. Also in the sensor 10 </ b> A having such a configuration, the first and second springs 51 and 52 are applied when a driving voltage is applied between the weight portion 32 and the driving electrode 27, as in the sensor 10 of the first embodiment. The body portion 31 and the weight portion 32 are displaced in the Z direction, and the weight portion 32 comes into contact with the stopper 29 so that the initial position of the movable portion 11 can be accurately set.

(Third embodiment)
Next, a third embodiment will be described with reference to FIG. In addition, the same code | symbol is attached | subjected about the thing similar to 1st Example, and the description is abbreviate | omitted suitably. The sensor 10B according to the third embodiment is different from the first embodiment in that the first spring 34 is changed to the torsion bar 61. More specifically, the sensor 10 </ b> B shown in FIG. 8 includes a pair of torsion bars 61 connected to one anchor 62. The anchor 62 is formed at a central portion in the Y direction on one end side in the X direction on the substrate 12 (see FIG. 2), and is erected along the Z direction. The anchor 62 has a torsion bar 61 formed on each side surface in the Y direction. The torsion bar 61 has a bar shape formed along the Y direction. The torsion bar 61 has one end in the Y direction connected to the anchor 62 and the other end connected to the first connection 63 of the main body 31.

  In the main body 31, a pair of first connection parts 63 projecting in the X direction are formed at both ends of the short side on the anchor 62 side, and the first connection parts 63 are supported by the anchor 14 via the torsion bar 61. ing. In the sensor 10 </ b> B, the anchor 62 is provided on a straight line passing through the center in the Y direction of the main body 31 in a state of being supported by the anchor 62 and parallel to the X direction. The torsion bar 61 and the anchor 62 are provided between the pair of first connecting portions 63 located at positions facing each other in the Y direction. Thereby, the weight part 32 and the main-body part 31 are supported rotatably with respect to the anchor 14 via the torsion bar 61. The main body 31 rotates around the rotation axis along the Y direction passing through the center of the torsion bar 61 in the X direction. Similar to the sensor 10 of the first embodiment, the sensor 10B having such a configuration is configured such that when a drive voltage is applied between the weight portion 32 and the drive electrode 27, the torsion bar 61 is twisted. The part 31 and the weight part 32 rotate in the Z direction around the rotation axis. In the sensor 10B, the weight portion 32 abuts against the stopper 29, and the initial position of the movable portion 11 can be set with high accuracy.

(Fourth embodiment)
Next, a fourth embodiment will be described with reference to FIG. In addition, the same code | symbol is attached | subjected about the thing similar to 1st Example, and the description is abbreviate | omitted suitably. The sensor 10C according to the fourth embodiment is different from the sensor 10 according to the first embodiment as an acceleration sensor in that the vibration portion 70 that vibrates the main body portion 31 is added and configured as an angular velocity sensor. This is different from the first embodiment. The angular velocity sensor 10C shown in FIG. 9 rotates in the Y axis with the Y direction as the rotation axis in a state where the movable portion 11 (main body portion 31) that can be displaced in two directions of the X direction and the Z direction is vibrated in the X direction (see FIG. 9). The angular velocity is detected by utilizing the fact that the main body 31 and the movable electrode 36 are displaced in the Z direction by the Coriolis force (inertial force) when the angular velocity of the rotation (see the arrow indicating the rotation inside) is applied. Yes.

  More specifically, the angular velocity sensor (hereinafter referred to as “sensor”) 10 </ b> C is provided with a vibrating portion 70 in a region opposite to the movable electrode 36 in the X direction of the main body portion 31. The vibration part 70 includes a first vibration electrode 71 connected to an external circuit via electrodes and wiring (both not shown) on the substrate 12, and a second vibration electrode 72 formed integrally with the main body part 31. With. The first vibration electrode 71 is formed in a comb-like shape in which electrodes 71A formed to protrude in the X direction are formed at equal intervals along the Y direction. The first vibration electrode 71 is provided with a plurality of pairs (two pairs in the illustrated example). The first vibration electrode 71 is provided at a position where the first vibration electrode 71 of each set is a target with respect to a straight line along the Y direction, and each of the comb-shaped electrodes 71A faces each other in the X direction. doing. The plurality of first vibration electrodes 71 are juxtaposed along the X direction. The pair of first vibration electrodes 71 is provided with a second vibration electrode 72 between the X directions. The second vibration electrode 72 is provided with an electrode 72A formed so as to protrude from both sides in the X direction from a rod-shaped electrode extending in the Y direction provided at a position in the middle of the pair of first vibration electrodes 71 in the X direction. It has been. In the second vibration electrode 72, both end portions of a rod-shaped electrode extending in the Y direction are integrally formed with the main body portion 31. The second vibration electrode 72 is provided such that the electrode 72A is inserted between the electrodes 71A of the first vibration electrode 71 facing on both sides in the X direction. The first and second vibrating electrodes 71 and 72 are formed of a parallel plate capacitor by electrodes 71A and 72A facing each other with a predetermined gap in the Y direction. The electrode 71A of the first vibration electrode 71 is opposite to the direction along the X direction with the electrode 72A of each second vibration electrode 72 when an AC drive signal is applied from an external circuit. Are alternately generated, and the main body 31 is vibrated in the X direction (left-right direction in the figure).

  In the angular velocity detection operation, for example, in the sensor 10C, a driving voltage is applied from an external circuit between the driving electrode 27 and the weight portion 32, and the weight portion 32 is displaced in the -Z direction (see FIG. 3) by the stopper 29. The movement is restricted and the main body 31 including the movable electrode 36 is held at the initial position. Next, in the sensor 10 </ b> C, when a driving signal is applied to the first vibration electrode 71 from an external circuit, an electrostatic force in the X direction is generated between the electrodes 71 </ b> A and 72 </ b> A, and the main body portion 31 vibrates. In the sensor 10 </ b> C, when the angular velocity of the Y-axis rotation acts on the main body 31 in this state, a Coriolis force in the Z direction acts on the main body 31. For this reason, the main body 31 and the movable electrode 36 are displaced in the Z direction (+ Z direction or −Z direction) according to the magnitude of the angular velocity of the Y-axis rotation. In the sensor 10 </ b> C, the facing area of the movable electrode 36 and the fixed electrode 25 varies according to the displacement of the movable electrode 36, and the angular velocity is detected based on a detection signal corresponding to the amount of change in capacitance between both electrodes. Accordingly, like the sensor 10 of the first embodiment, the angular velocity sensor 10C has an angular velocity in a state where the weight portion 32 is in contact with the stopper 29 and the initial position of the movable portion 11 is accurately set. Detection is possible.

(5th Example)
Next, a fifth embodiment will be described with reference to FIGS. In addition, the same code | symbol is attached | subjected about the thing similar to 2nd Example shown in FIG. 7, and the description is abbreviate | omitted suitably. In the sensor 10D according to the fifth embodiment, the sensor 10A according to the second embodiment has a configuration in which the movable electrode 36 and the fixed electrode 25 are provided in one place, whereas the movable electrode 36 and the fixed electrode 25 are provided in two places. The point provided at the target position is different from the second embodiment. The sensor 10 </ b> D shown in FIG. 10 is provided with two movable parts 81 and 82 that share the weight part 32.

  In the sensor 10D, each of the movable portions 81 and 82 is held by a first spring 51 connected to the anchor 14 provided on both sides in the X direction. The movable parts 81 and 82 are connected via a second spring 52 to one weight part 32 provided at the center part in the X direction of the sensor 10D. The drive electrode 27 provided on the substrate 12 (see FIG. 11) is provided at a position facing the weight portion 32 in the Z direction. Further, the substrate 12 is provided with stoppers 29 on both sides of the drive electrode 27 in the X direction, and the stoppers 29 face the weight part 32 in the Z direction. Each of the movable portions 81 and 82 is formed with a movable electrode 36 facing the fixed electrode 25 fixed to the substrate 12. The fixed electrode 25 and the movable electrode 36 face each other in the X direction to constitute a parallel plate capacitor. The movable electrode 36 provided in each of the movable portions 81 and 82 is a target position in the X direction with respect to a straight line along the Y direction passing through the central portion of the weight portion 32 in the X direction. In the sensor 10D having such a configuration, when a driving voltage is applied between the weight portion 32 and the driving electrode 27, the first and second springs 51 and 52 are elastically deformed, and each of the movable portions 81 and 82 is elastically deformed. One weight portion 32 shared by the main body portion 31 and the movable portions 81 and 82 is displaced in the Z direction. In the sensor 10D, the weight portion 32 provided at the center in the X direction is displaced in the Z direction, and the weight portion 32 abuts against the stopper 29 so that the initial positions of the movable portions 81 and 82 are set with high accuracy.

  As shown in FIG. 11, in the initial position where the drive voltage is applied between the weight portion 32 and the drive electrode 27, the sensor 10D is symmetrical from both sides in the X direction toward the center portion (left and right in FIG. 11). The movable parts 81 and 82 are held at the initial positions in a state of being inclined (symmetric). Here, the movable portions 81 and 82 are held in an inclined state so that the distance from the substrate 12 becomes shorter from the anchor 14 side on both sides in the X direction toward the central weight portion 32 side. The movable parts 81 and 82 are in a state in which the movable electrodes 36 arranged along the X direction are displaced in the −Z direction. As the movable parts 81 and 82 are inclined, the flat plate electrode part 36B of the movable electrode 36 is displaced in the -Z direction together with the main body part 31, and the closer to the weight part 32 in the X direction, the closer the flat plate electrode part 36B is to the -Z direction. The minute movement amount (for example, a movement amount on the order of several nanometers) is increased. Accordingly, each of the plate electrode portions 36B is displaced by a different amount of movement in the −Z direction while the fixed electrode 25 fixed to the substrate 12 is not displaced, so that the plate electrode portion 36B closer to the weight portion 32 can be obtained. The greater the amount of change in capacitance with the opposed fixed electrode 25, the greater the amount. Such a sensor 10D has, for example, a displacement amount that varies depending on the capacitance between each plate electrode portion 36B and the fixed electrode 25 when rotation or the like occurs in the movable portions 81 and 82 (each main body portion 31) in detecting acceleration. Fluctuation may occur and the detection accuracy of acceleration may be affected.

  Therefore, in the sensor 10D, the movable electrode 36 and the fixed electrode 25 of each of the movable portions 81 and 82 are provided at symmetrical positions in the X direction, so that the capacitance between each plate electrode portion 36B and the fixed electrode 25 can be increased. It is the structure which reduces the difference of the fluctuation | variation which arises. For example, the sensor 10 </ b> D calculates the average value of the change amounts of the mutual capacitances of the movable parts 81 and 82 that vary according to the acceleration so that the difference in variation does not affect the detection accuracy of the acceleration. An external circuit is configured. As a result, the sensor 10D can reduce the difference in fluctuation caused by the rotation of the movable portions 81 and 82 with respect to the capacitance between the movable electrode 36 (particularly, the plate electrode portion 36B) and the fixed electrode 25, and the acceleration. The detection accuracy can be improved.

Needless to say, the present invention is not limited to the above-described embodiments, and various improvements and modifications can be made without departing from the spirit of the present invention.
For example, the physical quantities (acceleration and angular velocity) detected by the sensors 10, 10A to 10D of the above-described embodiments and the directions in which the physical quantities can be detected (such as the Z direction) are merely examples, and can be changed as appropriate.
Further, the shape and configuration of each member is an example, and may be changed as appropriate. For example, in each of the embodiments described above, the stopper 29 is provided on the substrate 12, but it may be formed protruding from the inner wall of the frame portion 13.

  Incidentally, the sensors 10, 10A to 10D are examples of capacitive sensors. The movable part 11 is an example of a movable part. The substrate 12 is an example of a substrate. The anchor 14 is an example of a fixing part. The core substrate 21 is an example of a core substrate. The insulating layer 22 is an example of an insulating layer. The fixed electrode 25 is an example of a fixed electrode. The drive electrode 27 to which a drive voltage is applied between the movable portion 11 and the weight portion 32 is an example of the drive electrode. The stopper 29 is an example of a restricting portion. The main body 31 is an example of a main body. The weight part 32 is an example of a regulated part of the movable part. The movable electrode 36 including the frame-shaped electrode portion 36A and the plate electrode portion 36B is an example of a movable electrode. The first springs 34 and 51 and the torsion bar 61 are examples of a first elastic member. The second springs 41 and 52 are an example of a second elastic member. The X direction and the Y direction are examples of plane directions parallel to the plane of the substrate. The Z direction is an example of a direction perpendicular to the plane of the substrate.

10, 10A to 10D Capacitive sensor, 11 movable part, 12 substrate, 14 anchor, 21 core substrate, 22 insulating layer, 25 fixed electrode, 27 driving electrode, 29 stopper, 31 body part, 32 weight part, 36 movable Electrode, 34, 51 First spring, 41, 52 Second spring.

Claims (5)

A substrate,
A movable part provided so as to be swingable by being separated from the substrate;
A movable electrode provided in the movable part;
The opposed area of the movable electrode, which is fixedly provided on the substrate and faces away from the movable electrode in a plane direction parallel to the plane of the substrate, varies due to application of a physical quantity to the movable portion, and the variation of the opposed area And a fixed electrode whose capacitance varies with the movable electrode,
A drive voltage is applied between the movable part and the position of the movable part in a direction perpendicular to the plane of the substrate is displaced by electrostatic force, and the relative position of the movable electrode is shifted with respect to the fixed electrode. A drive electrode that varies the capacitance;
A restricting portion for restricting movement of the restricted portion of the movable portion that is displaced by the electrostatic force, and holding the movable portion at an initial position;
A capacitive sensor characterized by comprising: The substrate has a core substrate and an insulating layer formed on the core substrate,
The capacitive sensor according to claim 1, wherein the restricting portion is provided on the insulating layer that is positioned to face the restricted portion in a direction perpendicular to the plane of the substrate. The movable part is
A main body provided with the movable electrode;
A first elasticity that connects the main body portion to a fixing portion that is fixed to the substrate, and holds the main body portion so as to be swingable in a direction perpendicular to the plane of the substrate with respect to the fixing portion. Members,
A second elastic member that connects the regulated portion to the main body portion and holds the regulated portion so as to be swingable in a direction perpendicular to the plane of the substrate with respect to the main body portion;
The capacitive sensor according to claim 1, further comprising: The main body is formed in a plate shape having a rectangular shape when viewed from a direction perpendicular to the plane of the substrate, and the first elastic member is connected to a short side on one end side in the longitudinal direction, and the longitudinal direction The second elastic member is connected to the short side on the other end side of
The drive electrode is provided on the substrate at a position facing the regulated portion in a direction perpendicular to the plane of the substrate, and the drive voltage is applied between the regulated electrode and the regulated portion. The capacitive sensor according to claim 3, wherein: At least one set of the main body provided at each of the positions that are symmetrical with respect to the regulated portion along the plane direction parallel to the plane of the substrate,
In one set of the main body portions, the position where the movable electrode of one of the main body portions is provided is symmetrical in the plane direction with respect to the position where the movable electrode of the other main body portion is provided and the regulated portion. Provided at the position
5. The capacitive sensor according to claim 3, wherein the fixed electrode is provided to face the movable electrode of each of the pair of the main body portions. 6.

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