Impact sensor

Abstract

To provide an impact sensor with low consumption power and high durability, in which the wrong detection of impact is reduced.SOLUTION: An impact sensor 300 includes a frame part 1 including a detection electrode 3, and a movable element that includes a movable electrode 2 and is displaceable upon the impact from the outside. The movable element is supported by a stationary element through a spring part 4 and upon the impact, causes the spring part 4 to extend and contract so as to bring the movable electrode 2 into contact with the detection electrode 3 and by detecting the electric connection between the movable electrode 2 and the detection electrode 3 when the movable electrode 2 gets into contact with the detection electrode 3, the impact is detected. The detection electrode 300 is supported entirely in the displaceable manner along with the displacement of the movable electrode 2 in the state of being in contact with the movable electrode 2.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to an impact sensor. [Background technology]

[0002] Patent document 1 discloses that a movable electrode is supported by a spiral elastic body, the central part of the movable electrode is cylindrical, and a fixed electrode is arranged inside the cylindrical shape at a predetermined distance, and when an external impact occurs, the movable electrode is displaced relative to the fixed electrode due to inertial force, and the external impact is detected when the movable electrode comes into contact with the fixed electrode. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2016-161500 A Summary of the Invention [Problem to be solved by the invention]

[0004] However, in the configuration of Patent Document 1, when an external impact is received, the contact time between the movable electrode and the fixed electrode is short, so the circuit that detects the contact needs to be set to respond at a high frequency. In this case, however, noise is likely to be mistakenly detected as an impact signal, and it is also difficult to keep the power consumption of the circuit low. Furthermore, because the impact force caused by the contact is large, repeated contact causes wear and damage to the components, reducing durability.

[0005] SUMMARY OF THE INVENTION It is therefore an object of one aspect of the present invention to provide an impact sensor that reduces false impact detection, has low power consumption, and is highly durable. [Means for solving the problem]

[0006] According to one aspect of the present invention, an impact sensor includes a stator including a detection electrode, and a movable electrode that is displaceable when subjected to an external impact, wherein the movable electrode is supported by the stator via a first elastic body and receives an impact, causing the first elastic body to expand and contract, bringing the movable electrode into contact with the detection electrode, and detecting the electrical connection between the movable electrode and the detection electrode when the movable electrode comes into contact with the detection electrode, and the detection electrode is supported so that its entirety can be displaced in accordance with the displacement of the movable electrode while in contact with the movable electrode. [Effects of the Invention]

[0007] According to one aspect of the present invention, the entire detection electrode is displaced as the mover moves, allowing the contact time between the movable electrode and the detection electrode to be long, and the circuit that detects contact between the movable electrode and the detection electrode to be designed to respond at a low frequency. This reduces the frequency of false detection of noise as an impact signal, and also enables the circuit to consume less power. Furthermore, because the detection electrode is displaced as the mover moves, the impact of the mover on the detection electrode can be reduced, so even if the mover and the detection electrode repeatedly come into contact with each other, damage and wear are suppressed, improving durability. [Brief explanation of the drawings]

[0008] [Figure 1] FIG. 1 is a plan view of the impact sensor according to the present embodiment. [Figure 2] FIG. 2 is a diagram showing the operation when an impact is applied to the impact sensor according to this embodiment, and is a diagram showing when the movable electrode (first recess) comes into contact with the contact electrode (first convex portion). [Figure 3] Figure 3 is a diagram showing the operation when an impact is applied to the impact sensor of this embodiment, in which the movable electrode further presses the contact electrode (first convex portion) from the state in Figure 2, deforming the second member supporting the contact electrode, causing the movable electrode to further displace together with the contact electrode and come into contact with the second convex portion (second fixed electrode). [Figure 4] FIG. 4 is a diagram showing specific points of the mover for investigating the relationship between the impact load and the displacement of the mover. [Figure 5] FIG. 5 is a diagram showing the relationship between the impact load and the displacement of a specific point of the mover. [Figure 6] FIG. 6 is a schematic diagram showing a state in which the impact sensor according to this embodiment is mounted on a substrate. [Figure 7] FIG. 7 is a schematic diagram of an electronic tag including an impact sensor according to this embodiment. [Figure 8] FIG. 8 is a circuit diagram showing an example of a latch circuit that constitutes an electronic tag. [Figure 9] FIG. 9 is a flowchart showing the operation flow of an electronic tag. [Figure 10] FIG. 10 is a diagram for explaining how to use an electronic tag. DETAILED DESCRIPTION OF THE INVENTION

[0009] The embodiments described below are not limited to the drawings described by the brief description of the drawings.

[0010] A first aspect of the present invention is an impact sensor that includes a stator including a detection electrode, and a movable element that includes a movable electrode and is displaceable when subjected to an external impact, wherein the movable element is supported by the stator via a first elastic body and receives the impact, causing the first elastic body to expand and contract, bringing the movable electrode into contact with the detection electrode, and detects the impact by detecting the electrical connection between the movable electrode and the detection electrode when the movable electrode comes into contact with the detection electrode, and the detection electrode is supported so that its entirety can be displaced in accordance with the displacement of the movable electrode while in contact with the movable electrode.

[0011] According to the first aspect, the buffer electrode displaces with the movement of the movable element, allowing the contact time between the movable electrode and the buffer electrode to be extended, and the circuit that detects contact between the movable electrode and the buffer electrode can be designed to respond at a low frequency. This reduces the frequency of false detection of noise as an impact signal, and also enables the circuit to consume less power. Furthermore, because the buffer electrode displaces with the movement of the movable element, the impact when the movable element and the buffer electrode come into contact can be reduced, thereby reducing damage and wear even when the movable element and the buffer electrode come into repeated contact with each other, improving durability.

[0012] A second aspect of the present invention is an impact sensor in which, in the first aspect, the detection electrode is supported on the stator via a second elastic body, and the detection electrode is displaced in the displacement direction of the movable electrode while deforming the second elastic body while in contact with the movable electrode from the position of the detection electrode when the movable electrode contacts the detection electrode.

[0013] According to the second aspect, the detection electrode is displaceable as a whole when the second elastic body is deformed by the force applied by the movable element, thereby making it possible to easily construct a configuration that extends the contact time between the movable electrode and the detection electrode.

[0014] A third aspect of the present invention is an impact sensor in which, in the first or second aspect, one of the movable electrode and the detection electrode includes a first recess whose depth direction is perpendicular to the displacement direction, and the other of the movable electrode and the detection electrode includes a first convex portion whose at least a portion is accommodated in the first recess, and the movable electrode is displaced so that the first convex portion and the first recess come into contact with each other, and the impact is detected when the movable electrode and the detection electrode come into contact.

[0015] According to the third aspect, contact between the movable electrode and the detection electrode can be detected with a simple configuration.

[0016] A fourth aspect of the present invention is the impact sensor according to the third aspect, wherein the first convex portion is arranged on the detection electrode, and the first concave portion is arranged on the movable electrode.

[0017] According to the fourth aspect, it is possible to suppress rotation of the movable electrode when it receives an impact (inertial force).

[0018] A fifth aspect of the present invention is an impact sensor in which, in any one of the first to fourth aspects, the first elastic body is arranged in a pair so as to sandwich the movable electrode from both sides in the displacement direction of the movable electrode.

[0019] According to the fifth aspect, by suppressing displacement in directions other than the direction sandwiching the movable electrode, it is possible to detect an impact in a specific direction with high accuracy.

[0020] A sixth aspect of the present invention is an impact sensor in which, in any one of the second to fourth aspects, the second elastic body is arranged in a pair so as to sandwich the detection electrode from both sides in the displacement direction of the movable electrode.

[0021] According to the sixth aspect, the orientation of the contact electrode does not change even when the second elastic body is deformed, and therefore, the change in the contact state between the movable electrode and the contact electrode when the movable electrode presses the contact electrode can be reduced, thereby enabling highly accurate detection of impact.

[0022] A seventh aspect of the present invention is an impact sensor which is any one of the second to sixth aspects, in which a first fixed electrode is arranged on the stator, and the second elastic body is a beam portion including a fixed end fixed to the first fixed electrode and a movable end connected to the detection electrode and arranged in a direction intersecting the displacement direction, and in which the beam portion is deformed when the movable end is displaced in the displacement direction.

[0023] According to the seventh aspect, the second elastic body can be constructed with a simple structure.

[0024] An eighth aspect of the present invention is an impact sensor that is any one of the second to sixth aspects, wherein a first fixed electrode is arranged on the stator, the detection electrode includes a contact electrode in contact with the movable electrode and a first member extending from the contact electrode in a direction along the displacement direction, the second elastic body includes a pair of second members extending from both longitudinal ends of the first member in a direction intersecting the displacement direction and connected to the first fixed electrode, the contact electrode is electrically connected to the first fixed electrode via the first member and the second member, the first member displaces in the displacement direction when it receives a force from the movable electrode in a direction along the displacement direction via the contact electrode, the second member has a fixed end at the connection position with the first fixed electrode and a movable end at the connection position with the first member, and when the movable end receives a force from the first member, it deforms in such a manner that the fixed end does not displace but the movable end displaces.

[0025] According to the eighth aspect, the detection electrode including the contact electrode that displaces in parallel with the movable electrode can be constructed with a simple configuration.

[0026] A ninth aspect of the present invention is the stator of the eighth aspect, wherein the frame is a rectangular frame portion including a first beam including the contact electrode, a second beam connected to one end of the first beam in a longitudinal direction and intersecting the first beam, a third beam connected to the other end of the first beam in the longitudinal direction and arranged opposite to and parallel to the second beam, and a fourth beam connecting an end of the second beam opposite to the end of the second beam in the longitudinal direction connected to the first beam and an end of the third beam opposite to the end of the third beam in the longitudinal direction connected to the first beam. a first slit extending along the longitudinal direction of the first beam is disposed on the inner peripheral side of the frame portion of the first beam, the first slit extending to a connection position between the first beam and the second beam and a connection position between the first beam and the third beam; a second slit extending from an end of the first slit on the second beam side to a midpoint in the longitudinal direction of the second beam is disposed in the second beam; and a third slit extending from an end of the first slit on the third beam side to a midpoint in the longitudinal direction of the third beam is disposed in the third beam; and the first member is One of the pair of second members forms a portion of the first beam from the first slit to the inner periphery of the frame portion, has a connection position with the frame portion as a first fixed end and a connection position with the first member as a first movable end, and is deformed in a manner such that the first movable end is displaced relative to the first fixed end by receiving a force from the first member, and the other of the pair of second members forms a portion of the first beam from the third slit to the inner periphery of the frame portion, and has a connection position with the frame portion as a second fixed end. a connection position with the first member being a second movable end, the second movable end being deformed in a manner that it is displaced relative to the second fixed end by receiving a force from the first member, the first fixed electrode being disposed in the frame portion so as to surround a slit that integrates the first slit, the second slit, and the third slit, and being connected to the second member, when the contact electrode receives a force from the movable electrode toward the second beam, one of the pair of second members is deformed so that the first movable end is displaced in a direction that narrows the width of the second slit,The other of the pair of second members deforms so that the second movable end is displaced in a direction that widens the width of the third slit, and when the contact electrode receives a force from the movable electrode toward the third beam, one of the pair of second members deforms so that the first movable end is displaced in a direction that widens the width of the second slit, and the other of the pair of second members deforms so that the second movable end is displaced in a direction that narrows the width of the third slit.

[0027] According to the ninth aspect, the detection electrode, the second elastic body, and the stator can be formed by forming slits, so that the detection electrode and the second elastic body can be constructed by a simple manufacturing process.

[0028] A tenth aspect of the present invention is an impact sensor according to the eighth or ninth aspect, which is arranged in mirror symmetry about a line that passes through the contact electrode in a direction perpendicular to the displacement direction.

[0029] According to the tenth aspect, it is possible to make the reliability of impact detection in the two displacement directions of the movable electrode the same.

[0030] An eleventh aspect of the present invention is an impact sensor which is any one of the third to tenth aspects, wherein the stator has a first fixed electrode electrically connected to the detection electrode, and one of the movable electrode and a portion of the stator different from the first fixed electrode includes a second recess whose depth direction is perpendicular to the displacement direction, and the other of the movable electrode and the portion of the stator different from the first fixed electrode includes a second convex portion which is at least partially accommodated in the second recess, and the distance between the second convex portion and the second recess in the displacement direction is set wider than the distance between the first convex portion and the first recess in the displacement direction.

[0031] According to the eleventh aspect, the second convex portion and the second concave portion do not interfere with the contact between the first convex portion and the first concave portion, and the displacement of the movable electrode is stopped when the movable electrode has displaced an amount equal to the distance between the second convex portion and the second concave portion, thereby reducing damage caused by impact to the movable part of the impact sensor.

[0032] A twelfth aspect of the present invention is an impact sensor according to the eleventh aspect, wherein the first recess and the second recess are arranged on the movable electrode, the first convex portion is arranged on the detection electrode, and the second convex portion is arranged on the stator.

[0033] According to the twelfth aspect, it is possible to suppress rotation of the movable electrode when it receives an impact (inertial force).

[0034] A thirteenth aspect of the present invention is an impact sensor according to the eleventh aspect, wherein the first convex portion and the second convex portion are arranged on the movable electrode, the first concave portion is arranged on the detection electrode, and the second concave portion is arranged on the stator.

[0035] According to the thirteenth aspect, a part of the movable electrode is housed in the contact electrode and the stator, and therefore electrical noise in the movable electrode can be reduced accordingly.

[0036] A 14th aspect of the present invention is an impact sensor in which, in any one of the second to 13th aspects, the stator, the movable member, the first elastic body, and the second elastic body are one piece and are formed from a laminate in which an active layer is stacked on a support layer, the portion of the one piece relating to the stator is formed from the laminate, and the portion of the one piece relating to the movable member, the first elastic body, and the second elastic body is formed from the active layer obtained by removing the support layer from the laminate.

[0037] According to the fourteenth aspect, the impact sensor can be formed by etching the stack (SOI wafer), and impact sensors can be easily manufactured in large quantities.

[0038] A 15th aspect of the present invention is an impact sensor which is any one of the second to 13th aspects, wherein the stator is provided with a first fixed electrode electrically connected to the detection electrode and a second fixed electrode insulated from the first fixed electrode, and the second fixed electrode extends into the first elastic body and is thereby electrically connected to the movable electrode.

[0039] According to the fifteenth aspect, it is possible to easily set up a configuration in which the second fixed electrode and the first fixed electrode are electrically connected by contact between the movable electrode and the contact electrode.

[0040] Hereinafter, embodiments will be described with reference to the drawings.

[0041] [Configuration of the shock sensor 300] 1 is a plan view of an impact sensor 300 according to this embodiment. In FIG. 1 (and the other figures as well), the X and Y directions are assumed to be perpendicular to each other. In the following description, the "X direction" may be referred to as the "left-right direction," the "Y direction" as the "up-down direction," the "+X direction" as the "right direction," the "-X direction" as the "left direction," the "+Y direction" as the "upward direction," and the "-Y direction" as the "downward direction."

[0042] 1, the shock sensor 300 has a rectangular (square) shape in a plan view. The shock sensor 300 includes a rectangular (square) frame 1, a movable electrode 2 arranged inside the frame 1, and a spring 4 arranged in a region between the frame 1 and the movable electrode 2, supported by the frame 1, and supporting the movable electrode 2.

[0043] The frame 1 has a substantially rectangular (square) opening, in which the movable electrode 2 and the spring portion 4 are housed.

[0044] The frame portion 1 includes a first beam 141 extending in the left-right direction, a second beam 142 connected to the left end of the first beam 141 and extending upward, a third beam 143 connected to the right end of the first beam 141 and extending upward, and a fourth beam 144 connecting the upward end of the second beam 142 and the upward end of the third beam 143 and extending in the left-right direction.

[0045] The movable electrode 2 is all or part of a mover supported from both left and right sides by spring portions 4 whose rigidity (elasticity) in the left and right direction is lower than its rigidity (elasticity) in the up and down direction, and is an electrode that can be selectively displaced in the left and right direction by the spring portions 4, with displacement in the up and down direction being more strongly suppressed than displacement in the left and right direction. When the shock sensor 300 receives an external shock (acceleration) in the left and right direction, the movable electrode 2 (mover) generates an inertial force due to the mass of the movable electrode 2 (mover), and is displaced in the left and right direction relative to the frame portion 1.

[0046] In the frame 1, the portion other than where the first fixed electrode 11 is arranged (excluding the groove portion 13 described later) serves as the second fixed electrode 12.

[0047] In the frame portion 1, a groove portion 13 is arranged between the first fixed electrode 11 and the second fixed electrode 12, and the first fixed electrode 11 and the second fixed electrode 12 are insulated from each other by the groove portion 13. In addition, the second fixed electrode 12 is connected to the movable electrode 2 by extending to the spring portion 4 and the movable element.

[0048] The first fixed electrode 11 is arranged to cover almost the entire area of ​​the first beam 141, the area outside the frame portion 1 beyond the second slit 152 of the second beam 142, and the area outside the frame portion 1 beyond the third slit 153 of the third beam 143. The detection electrode 3 has a contact electrode 33 (first convex portion) that extends upward, i.e., toward the movable electrode 2, at a position facing the center of the lower edge of the movable electrode 2. Meanwhile, a first concave portion 21 is formed on the edge of the movable electrode 2 facing the contact electrode 33 (first convex portion).

[0049] The contact electrode 33 (first convex portion) forms a gap between itself and the first concave portion 21 in the vertical and horizontal directions, and at least a portion of it is housed within the first concave portion 21 without contacting the first concave portion 21. Although the contact electrode 33 has a convex shape (first convex portion) as a whole, the first concave portion 21 may be formed on an edge of the contact electrode 33 facing the movable electrode 2, and the first convex portion may be disposed at a position facing the first concave portion 21 of the movable electrode 2.

[0050] The fourth beam 144 has a second convex portion 121 extending downward, i.e., toward the movable electrode 2, at a position facing the center of the edge extending in the left-right direction of the movable electrode 2. Meanwhile, a second concave portion 22 is formed on the edge of the movable electrode 2 facing the second convex portion 121. Alternatively, the second convex portion 121 may be disposed on the edge of the movable electrode 2 facing the fourth beam 144, and the second concave portion 22 may be formed on the fourth beam 144 at a position facing the second convex portion 121.

[0051] The second protrusion 121 forms a gap between itself and the second recess 22 in the vertical and horizontal directions, and at least a portion of it is housed within the second recess 22 in a state of not contacting the second recess 22.

[0052] Here, the left side surface of the first recess 21 and the left side surface of the second recess 22 are located at the same position in the left-right direction, and the right side surface of the first recess 21 and the right side surface of the second recess 22 are located at the same position in the left-right direction. That is, the left-right center of the first recess 21 and the left-right center of the second recess 22 are located at the same position in the left-right direction. Therefore, the movable electrode 2 has an "H" shape with the vertical direction as the vertical direction. The movable electrode 2 has a shape that is mirror-symmetrical with respect to a line (dashed line S shown in FIG. 1 ) that is parallel to the vertical direction and passes through the left-right center of the movable electrode 2 (i.e., the left-right center of the first recess 21 and the second recess 22). By making the movable electrode 2 "H" shaped in this way, vibrations in directions other than the direction sandwiched between the spring portions 4 (left-right direction) and rotational motion around a rotation axis perpendicular to the left-right and up-down directions can be reduced, thereby reducing false detections by the impact sensor 300.

[0053] 1, the contact electrode 33 (first convex portion) and the second convex portion 121 are also arranged so as to be mirror symmetrical with respect to the dashed line S shown in Fig. 1, but the left-right width of the second convex portion 121 is set to be narrower than the left-right width of the contact electrode 33 (first convex portion). As a result, the gap (D2) between the second convex portion 121 and the second concave portion 22 is set to be wider than the gap (D1) between the contact electrode 33 (first convex portion) and the second concave portion 22.

[0054] In addition, the first convex portion (having approximately the same shape as the contact electrode 33) and the second convex portion 121 may be formed on the movable electrode 2, the first recess 21 may be formed on the contact electrode 33, and the second recess 22 may be formed on the second fixed electrode 12.

[0055] The spring portions 4 (spring portions 4L, 4R) are formed so that their rigidity (elasticity) against left-right forces is weaker than their rigidity (elasticity) against up-down forces, and are members that can selectively expand and contract in the left-right direction but whose expansion and contraction in the up-down direction is more strongly suppressed than that in the left-right direction. When the spring portions 4 receive a left-right inertial force from the movable electrode 2, they deform, thereby generating a restoring force.

[0056] The left spring portion 4L is connected to the left side of the fourth beam 144 and to the lower end of the left edge of the movable electrode 2.

[0057] The left-side spring portion 4L extends vertically in the area surrounded by the first beam 141, the movable electrode 2, the fourth beam 144, and the second beam 142, and has a zigzag structure that folds back and forth vertically between the first beam 141 and the fourth beam 144 multiple times by folding back at a position adjacent to the first beam 141 and a position adjacent to the fourth beam 144.

[0058] The right spring portion 4R is connected to the right side of the fourth beam 144 and to the lower end of the right edge of the movable electrode 2.

[0059] The right-side spring portion 4R extends vertically in the area surrounded by the first beam 141, the third beam 143, the fourth beam 144, and the movable electrode 2, and has a zigzag structure that moves back and forth vertically between the first beam 141 and the fourth beam 144 by folding back at a position adjacent to the first beam 141 and a position adjacent to the fourth beam 144.

[0060] The frame 1 is formed with a first slit 151, a second slit 152, and a third slit 153.

[0061] The first slit 151 is an opening that is disposed in the first beam 141 and extends in the left-right direction, and is disposed at a position adjacent to the inner periphery of the frame 1. The left end of the first slit 151 extends to the connection position between the first beam 141 and the second beam 142, and the right end of the first slit 151 extends to the connection position between the first beam 141 and the third beam 143.

[0062] The first beam 141 is separated by the first slit 151 into a first member 34 located on the inner periphery of the frame 1 and a first fixed electrode 11 located on the outer periphery of the frame 1 relative to the first slit 151. The first member 34 extends in the left-right direction and includes a contact electrode 33 (first convex portion). The contact electrode 33 is formed integrally with the first member 34. The contact electrode 33 and the first member 34 together form the detection electrode 3.

[0063] The second slit 152 is an opening that extends upward from the left end of the first slit 151 to a position midway along the second beam 142. The second slit 152 is disposed at a position adjacent to the inner periphery of the frame 1.

[0064] In the second beam 142, the portion closer to the inner periphery of the frame 1 than the second slit 152 becomes the second member 35A, and the portion closer to the outer periphery of the frame 1 than the second slit 152 and the portion of the frame 1 in the circumferential direction where the second slit 152 is not formed and which is inside the groove portion 13 becomes the first fixed electrode 11. The second member 35A extends in the vertical direction, is connected to the left end of the first member 34, and is cantilevered by the first fixed electrode 11.

[0065] The third slit 153 is an opening that extends upward from the right end of the first slit 151 to a position midway along the third beam 143. The third slit 153 is disposed at a position adjacent to the inner periphery of the frame 1.

[0066] In the third beam 143, the portion of the third beam 143 that is closer to the inner periphery of the frame 1 than the third slit 153 becomes the second member 35B, and the portion of the frame 1 that is closer to the outer periphery of the frame 1 than the third slit 153 and the portion of the frame 1 in the circumferential direction where the third slit 153 is not formed and that is closer to the inner side than the groove portion 13 becomes the first fixed electrode 11. The second member 35B extends in the vertical direction, is connected to the right end of the first member 34, and is cantilevered by the first fixed electrode 11.

[0067] The second member 35A (second elastic body) is an elastically deformable member with the connection position with the main body of the second beam 142 as a fixed end (first fixed end) and the connection position with the left end of the first member 34 as a movable end (first movable end).

[0068] The second member 35B (second elastic body) is a member that can be elastically deformed with a fixed end (second fixed end) at the connection position with the main body of the third beam 143 and a movable end (second movable end) at the connection position with the right end of the first member 34. The lengths of the second member 35A and the second member 35B in the vertical direction are set to be the same or approximately the same.

[0069] The contact electrode 33 (first convex portion) is separated from the first fixed electrode 11 by the first slit 151, but is electrically connected to the first fixed electrode 11 via the first member 34 and the second member 35A, or the first member 34 and the second member 35B.

[0070] The contact electrode 33 (first convex portion) is configured to be supported at both ends by the second member 35A and the second member 35B, but it is also possible to omit either the second member 35A or the second member 35B and have the contact electrode 33 (first convex portion) be supported at one end.

[0071] Alternatively, a configuration may be applied in which a first slit 151 is further disposed in the fourth beam 144, a second slit 152 is disposed so as to extend downward from the left end of the first slit 151, a third slit 153 is disposed so as to extend downward from the right end of the first slit 151, a first member 34 including a second convex portion 121 is formed on the inner periphery of the frame portion 1 of the fourth beam 144, a second member 35A is formed on the upper side of the second beam 142, and a second member 35B is formed on the upper side of the third beam 143. As a result, the second convex portion 121, like the contact electrode 33 (first convex portion), may be configured to come into contact with the movable electrode 2 and then be further pressed by the movable electrode 2, and the second members 35A and 35B may be elastically deformed, thereby displacing the second convex portion 121 in parallel with the movable electrode 2.

[0072] [Operation of the shock sensor 300] Fig. 2 is a diagram showing the behavior when an impact is applied to the impact sensor 300 according to this embodiment, showing the movable electrode 2 (first recess 21) coming into contact with the contact electrode 33 (first convex portion). Fig. 3 is a diagram showing the behavior when an impact is applied to the impact sensor 300 according to this embodiment, showing the movable electrode 2 further pressing against the contact electrode 33 (first convex portion) from the state shown in Fig. 2, deforming the second members 35A and 35B that support the contact electrode 33, causing the movable electrode 2 to further displace together with the contact electrode 33 (first convex portion) and come into contact with the second convex portion 121 (second fixed electrode 12).

[0073] When the shock sensor 300 receives an impact (acceleration) from, for example, the right side, an inertial force that displaces the movable electrode 2 relative to the frame 1 in the right direction is generated in the movable electrode 2, compressing the right spring portion 4R in the left-right direction and expanding the left spring portion 4L in the left-right direction, as shown in Fig. 2. When the impact (acceleration) from the right side exceeds a predetermined magnitude (first threshold), the movable electrode 2 (first recess 21) comes into contact with the contact electrode 33 (first protrusion), as shown in Fig. 2.

[0074] When an impact greater than the first threshold is applied to the impact sensor 300 from the right, the movable electrode 2 (first recess 21) in contact with the contact electrode 33 (first convex portion) further presses the contact electrode 33 (first convex portion) as shown in Fig. 3. Then, the second members 35A and 35B elastically deform in the direction (rightward) in which the movable electrode 2 presses, and the contact electrode 33 (first member 34) is displaced in the direction (rightward) in which the movable electrode 2 presses without changing its orientation. At this time, the displacement of each movable end due to the elastic deformation of the second members 35A and 35B is small, so the contact electrode 33 (first member 34) is displaced in parallel with the movable electrode 2.

[0075] When the impact (acceleration) from the right exceeds a predetermined magnitude (second threshold (a value greater than the first threshold)), the movable electrode 2 (second recess 22) comes into contact with the second protrusion 121 (second fixed electrode 12), as shown in Figure 3.

[0076] Conversely, although not shown in the figures, when the shock sensor 300 receives an impact from the left, an inertial force that displaces the movable electrode 2 leftward relative to the frame 1 is generated in the movable electrode 2, compressing the left spring portion 4L in the left-right direction and expanding the right spring portion 4R in the left-right direction. When the impact (acceleration) from the left exceeds a first threshold, the movable electrode 2 (first recess 21) comes into contact with the contact electrode 33 (first protrusion).

[0077] When an impact greater than the first threshold is applied to the impact sensor 300 from the left, the movable electrode 2 (first recess 21) further presses the contact electrode 33 (first convex portion). This causes the second members 35A and 35B to elastically deform in the direction (leftward) that the movable electrode 2 presses, and as a result, the contact electrode 33 (first member 34) is displaced in the direction (leftward) that the movable electrode 2 presses without changing its orientation. At this time, the displacement of each movable end due to the elastic deformation of the second members 35A and 35B is small, so the contact electrode 33 (first member 34) is displaced in parallel with the movable electrode 2.

[0078] When the impact (acceleration) from the left exceeds a predetermined magnitude (second threshold (greater than the first threshold)), the movable electrode 2 (second recess 22) comes into contact with the second fixed electrode 12 (second protrusion 121).

[0079] [Impact load and displacement of the mover] Fig. 4 is a diagram showing specific points (A, B) of the mover (movable electrode 2) for investigating the relationship between the impact load and the displacement of the mover. Fig. 5 is a diagram showing the relationship between the impact load and the displacement of the specific points (A, B) of the mover.

[0080] The inventors of the present application conducted a simulation to investigate the movement of the mover (movable electrode 2) of the shock sensor 300 of the present invention in response to a shock load in the left-right direction (FIG. 4).

[0081] Here, the gap (D1, Figure 1) between the first recess 21 arranged on the movable element (movable electrode 2) and the contact electrode 33 (first protrusion) was set to 45 μm, and the gap (D2, Figure 2) between the second recess 22 arranged on the movable element (movable electrode 2) and the second protrusion 121 arranged on the second fixed electrode 12 was set to 48 μm.

[0082] In addition, specific points (A) and (B) were set to measure the displacement of the mover.

[0083] The specific point (A) was set at the center of the edge extending in the left-right direction of the first recess 21 of the mover (movable electrode 2).

[0084] The specific point (B) was set at the center of the edge extending in the left-right direction of the second recess 22 of the mover (movable electrode 2).

[0085] In the shock sensor 300 shown in FIG. 4, when the mover (movable electrode 2) receives an impact load (inertial force) in the right direction, the specific point (A) and the specific point (B) are investigated, and the results shown in FIG. 5 are obtained.

[0086] The horizontal axis in FIG. 5 represents the impact load, where 1.00=100 [G], and the vertical axis represents the displacement [μm] of the mover in the left-right direction.

[0087] 5, the displacement of specific point (A) and specific point (B) increases in proportion to the magnitude of the impact load, and the displacement reaches 45 μm when the impact load reaches approximately 75 G. When the displacement is 45 μm, the first recess 21 of the mover (movable electrode 2) comes into contact with the contact electrode 33 (first protrusion), but up until this point, specific point (A) and specific point (B) are displaced in the same way, and the mover (movable electrode 2) is displaced in the left-right direction, i.e., parallel to the direction of the impact load.

[0088] On the other hand, when the impact load exceeds 75 [G], the mover (movable electrode 2) presses the contact electrode 33 (first convex portion), and the mover (movable electrode 2) and the contact electrode 33 (first convex portion) are displaced further to the right.

[0089] At this time, the movable element (movable electrode 2) elastically deforms the second member 35A and the second member 35B, but receives the restoring force, so the ratio of displacement of the specific point (A) and the specific point (B) to the impact load (the slope of the graph in Figure 5) becomes smaller than the ratio when the impact load is lower than 75 [G].

[0090] When the impact load is 100 [G], the displacement of specific point (A) is 45.4 [μm], but the displacement of specific point (B) is approximately 46 [μm]. Therefore, in the configuration of Figure 4, when the mover (movable electrode 2) is displaced to the right and the displacement of the mover exceeds 45 [μm], the mover rotates slightly clockwise.

[0091] The gap (D2 = 48 μm) between the second recess 22 of the movable element (movable electrode 2) and the second fixed electrode 12 (second convex portion 121) is approximately 3 μm larger than the gap (D1 = 45 μm) between the first recess 21 of the movable element (movable electrode 2) and the contact electrode 33 (first convex portion), but when the impact load is 300 G or more, the second recess 22 of the movable element (movable electrode 2) and the second fixed electrode 12 (second convex portion 121) come into contact.

[0092] In addition, in the modified example in Figure 4 where there are no first slits 151, second slits 152, or third slits 153 and the contact electrode 33 is fixed to the frame portion 1, when a predetermined impact load (e.g., 100 [G]) is applied to the movable element (movable electrode 2), the contact time between the movable element (first recess 21) and the contact electrode 33 (first convex portion) is approximately 0.6 [μsec].

[0093] On the other hand, when the second members 35A and 35B are elastically deformed as in this embodiment, the contact time between the mover (first recess 21) and the contact electrode 33 (first protrusion) was approximately 25 μsec.

[0094] Therefore, according to this embodiment, contact between the movable electrode 2 and the contact electrode 33 can be detected with high accuracy in the latch circuit 600 described below. Furthermore, compared to the modified example, in this embodiment, the magnitude of the impact when the movable electrode 2 and the contact electrode 33 come into contact can be reduced to 0.6 [μsec] / 25 [μsec] = 0.024, and can be further reduced to 0.01 or less by appropriate design. Therefore, even if the movable electrode 2 and the contact electrode 33 repeatedly come into contact with each other, damage and wear are suppressed, improving durability.

[0095] [Layer structure of the impact sensor 300] FIG. 6 is a schematic diagram showing a state in which the impact sensor 300 according to this embodiment is mounted on a mounting substrate 5. As shown in FIG.

[0096] The shock sensor 300 is formed of, for example, an SOI (Silicon On Insulator) wafer. The SOI wafer is formed by laminating an insulating layer 1b (SiO2) (support layer) made of SiO2 and an active layer 1c (Si) in that order on a silicon substrate 1a (support layer).

[0097] The manufacturing process for the impact sensor 300 involves, for example, etching (e.g., dry etching) the silicon substrate 1a and insulating layer 1b on the backside of the SOI wafer to match the contours of the frame portion 1, etching the active layer 1c on the front side of the SOI wafer to match the shapes of the first fixed electrode 11, the second fixed electrode 12, the movable electrode 2, the contact electrode 33, the first member 34, the second member 35A, the second member 35B, the spring portion 4, and the groove portion 13, and then metal plating the remaining portion of the active layer 1c on the front side of the SOI wafer to form the impact sensor 300.

[0098] Therefore, the surface of the active layer 1c of the impact sensor 300 (first fixed electrode 11, contact electrode 33, first member 34, second member 35A, second member 35B, second fixed electrode 12, movable electrode 2, spring portion 4) is covered with metal (e.g., copper) plating except for the groove portion 13. Therefore, the second fixed electrode 12 is electrically connected to the movable electrode 2 via a connection electrode (a portion of the second fixed electrode 12 extending into the spring portion 4 (FIG. 1)) arranged on the spring portion 4. Meanwhile, the insulating layer 1b is exposed in the groove portion 13.

[0099] As shown in FIG. 6, the impact sensor 300 is bonded to a mounting substrate 5 with an adhesive or the like so that the silicon substrate 1a faces downward, and electrodes (first fixed electrode 11, second fixed electrode 12) arranged on the active layer 1c are connected to a pad electrode 51 arranged on the mounting substrate 5 by a wire 52 made of gold (Au) or the like, and the pad electrode 51 is connected to a latch circuit 600 described below.

[0100] The width of the beam of the spring portion 4 is narrower than the thickness of the active layer 1c (frame portion 1 (part of the active layer 1c) and movable electrode 2), but the thickness of the spring portion 4 is set to be approximately the same as or the same as the thickness of the active layer 1c. This makes it difficult for the spring portion 4 to deform in directions perpendicular to the left-right and up-down directions (thickness direction), and for example, when the impact sensor 300 is placed horizontally, it is possible to reduce sinking of the movable electrode 2 in the thickness direction of the impact sensor 300.

[0101] [Electronic tag 100 including shock sensor 300] FIG. 7 is a schematic diagram of an electronic tag 100 including an impact sensor 300 according to this embodiment.

[0102] As shown in FIG. 7, the electronic tag 100 includes an impact sensor 300, a battery 400, a real-time clock (hereinafter referred to as RTC) 500, a latch circuit 600, a control circuit 700, an antenna 800, and a memory 900.

[0103] The RTC 500, latch circuit 600, control circuit 700, and memory 900 can each be provided as an IC (Integrated Circuit) chip. Also, some or all of these components may be mounted in a single IC package.

[0104] The electronic tag 100 is constructed by housing a substrate (for example, the mounting substrate 5 in FIG. 6) on which the above components are mounted in a resin tag body 200. The substrate may be a rigid substrate or a flexible substrate. The size of the electronic tag 100 is about several tens of millimeters in the longitudinal direction and about several millimeters in the thickness direction.

[0105] The battery 400 may be, for example, a button battery.

[0106] The RTC 500 has a clock function. The RTC 500 is electrically connected to the battery 400 so that power is constantly supplied to the RTC 500. The RTC 500 keeps time while power is being supplied to the RTC 500.

[0107] The impact sensor 300 is connected to the latch circuit 600 by electric wires S1 and S2, and is electrically connected to the battery 400 via the latch circuit 600. In this embodiment, the path for supplying power from the battery 400 to the impact sensor 300 is incorporated into the latch circuit 600.

[0108] The electric wire S1 is connected to the first fixed electrode 11, and the electric wire S2 is connected to the second fixed electrode 12 (ie, the movable electrode 2).

[0109] The shock sensor 300 is a mechanical sensor that is configured to conduct electricity when an impact (acceleration) equal to or greater than the minimum acceleration (the first threshold) is applied, and not conduct electricity when an impact (acceleration) equal to or greater than the minimum acceleration is not applied. The shock sensor 300 does not consume power from the battery 400 when an impact (acceleration) equal to or greater than the minimum acceleration is not applied.

[0110] The latch circuit 600 is electrically connected to the battery 400 , the impact sensor 300 , and the control circuit 700 .

[0111] The latch circuit 600 detects the conduction between the electric wires S1 and S2.

[0112] When the electric wires S1 and S2 are energized, the latch circuit 600 enters an ON state in which it supplies power to the control circuit 700, and maintains the ON state even if the energization is subsequently interrupted. After that, when the latch circuit 600 receives a control signal (power OFF signal) from the control circuit 700, it enters an OFF state in which it does not supply power to the control circuit 700. In the OFF state, the latch circuit 600 does not consume power from the battery 400. The latch circuit 600 will be described in detail later.

[0113] The control circuit 700 is electrically connected to the RTC 500, the latch circuit 600, the antenna 800, and the memory 900. When power is supplied from the latch circuit 600 to the control circuit 700, power is also supplied to the memory 900 via the control circuit 700. When the latch circuit 600 is turned on, power may be supplied directly from the latch circuit 600 to the memory 900.

[0114] When power is supplied from the latch circuit 600 , the control circuit 700 acquires the time from the RTC 500 and writes the acquired time information into the memory 900 .

[0115] In the electronic tag 100, when an acceleration (impact) whose absolute value is greater than or equal to a predetermined acceleration (first threshold) is applied to the impact sensor 300, the impact sensor 300 becomes powered, and as a result, the latch circuit 600 supplies power to the control circuit 700, which then obtains from the RTC 500 the time when the acceleration (impact) was applied to the impact sensor 300.

[0116] For example, if there is a time lag between when an impact (acceleration) is applied to the impact sensor 300 and when the control circuit 700 obtains the time from the RTC 500 due to factors such as insufficient processing power of the control circuit 700, the time lag can be corrected by the control circuit 700, thereby essentially obtaining the time when the impact (acceleration) was applied to the impact sensor 300.

[0117] When the control circuit 700 has completed writing the time to the memory 900, it outputs a control signal (power OFF signal) to the latch circuit 600, causing the latch circuit 600 to enter an OFF state in which no power is supplied to the control circuit 700 and the memory 900. This stops the supply of power to the control circuit 700 and the memory 900. The control circuit 700 and the memory 900 do not consume power from the battery 400 when the latch circuit 600 is in the OFF state.

[0118] The memory 900 is a non-volatile memory that retains written memory contents even when power is not supplied.

[0119] The antenna 800 receives radio waves emitted from a reader / writer 920 (see FIG. 10 ) and generates power for operating the control circuit 700 and the memory 900. The control circuit 700 reads information written in the memory 900 using the power generated by the antenna 800 and sends the read information from the antenna 800 to the reader / writer 920.

[0120] It is also possible to rewrite the information stored in the memory 900 using the reader / writer 920. Note that non-rewritable information is also stored in the memory 900. The non-rewritable information is, for example, the identification information of the electronic tag 100.

[0121] In this way, the electronic tag 100 of this embodiment is configured as a wireless communication tag (RFID tag) compatible with RFID (Radio Frequency Identification) technology.

[0122] The electronic tag 100 may be a BLE tag that employs a BLUETOOTH (registered trademark) Low Energy (BLE) communication method, which is a low-power consumption communication mode.

[0123] [Latch circuit 600] FIG. 8 is a circuit diagram showing an example of a latch circuit 600 that constitutes the electronic tag 100. As shown in FIG.

[0124] 8, the latch circuit 600 is an electronic circuit including a PNP transistor Tr1, an NPN transistor Tr2, a PNP transistor Tr3, an NPN transistor Tr4, resistors R1 to R11, and a capacitor C1. The latch circuit 600 is an electronic circuit that does not have any mechanically moving parts.

[0125] Resistors R1 and R2 form a series circuit, with one end of resistor R1 connected to a power supply (Vcc) and the other end connected to resistor R2. One end of resistor R2 is connected to resistor R1 and the other end is connected to electric wire S1. Electric wire S2 is grounded.

[0126] The emitter of transistor Tr1 is connected to battery 400 (Vcc), the collector is connected to resistor R3, and the base is connected to the connection point between resistors R1 and R2. One end of resistor R3 is connected to the collector of transistor Tr1 and the other end is grounded.

[0127] Resistors R4, R7, and R8 form a series circuit. One end of resistor R4 is connected to the connection midpoint between transistor Tr1 (collector) and resistor R3, and the other end is connected to resistor R7. Resistor R7 has one end connected to resistor R4 and the other end connected to resistor R8 and the base of transistor Tr2. Resistor R8 has one end connected to resistor R7 and the base of transistor Tr2, and the other end grounded.

[0128] One end of the capacitor C1 is connected to the midpoint between the resistors R4 and R7, and the other end is grounded.

[0129] The collector of the transistor Tr2 is connected to a resistor R9, the base is connected to a resistor R7, and the emitter is grounded.

[0130] The transistor Tr3 has an emitter connected to the battery 400 (Vcc), a base connected to a resistor R9, and a collector connected to a resistor R11.

[0131] One end of the resistor R9 is connected to the base of the transistor Tr3, and the other end is connected to the collector of the transistor Tr2.

[0132] One end of the resistor R11 is connected to the collector of the transistor Tr3, and the other end is connected to the control circuit 700 (power supply input side).

[0133] The collector of the transistor Tr4 is connected to a resistor R6, the base is connected to a resistor R10, and the emitter is grounded.

[0134] One end of the resistor R6 is connected to the connection point between the resistors R4 and R7, and the other end is connected to the collector of the transistor Tr4.

[0135] One end of the resistor R10 is connected to the base of the transistor Tr4, and the other end is connected to the control circuit 700 (control signal output side).

[0136] One end of the resistor R5 is connected to the connection midpoint between the resistor R11 and the control circuit 700 (power supply input side), and the other end is connected to the connection midpoint between the resistor R4 and the resistor R7.

[0137] In the initial state (before acceleration is applied), the shock sensor 300 is not conducting, and the transistors Tr1 to Tr4 are in the OFF state (not conducting).

[0138] When the impact sensor 300 is energized, the voltage at the connection point between the resistors R1 and R2 drops, and the voltage at the base of the transistor Tr1 drops, causing the transistor Tr1 to turn on (energize).

[0139] When transistor Tr1 is turned on, a voltage is applied from transistor Tr1 to resistor R3 and the series circuit of resistors R4, R7, and R8, and the voltage at the connection midpoint of resistors R4 and R7 is applied to capacitor C1, and the voltage at the connection midpoint of resistors R7 and R8 is applied to the base of transistor Tr2.

[0140] Capacitor C1 is charged to the voltage at the junction of resistors R4 and R7.

[0141] A voltage at the midpoint of the connection between resistors R7 and R8 is applied to the base of transistor Tr2, and when the voltage drop across resistor R8, i.e., the voltage between the base and emitter of transistor Tr2, exceeds the threshold voltage (e.g., 0.6 V), transistor Tr2 turns ON.

[0142] When the transistor Tr2 is turned on, the base voltage of the transistor Tr3 drops, causing the transistor Tr3 to be turned on.

[0143] When transistor Tr3 is turned ON, power is supplied to the control circuit 700 (power input side) from the battery 400 (Vcc) connected to the emitter of transistor Tr3 via the collector of transistor Tr3 and resistor R11. At this time, the voltage at the connection point between resistor R11 and the control circuit 700 is applied to resistors R5, R7, and R8. Therefore, the voltage at the collector of transistor Tr3, which is applied to the connection point between resistors R7 and R8, becomes the base voltage of transistor Tr2. As a result, even if the impact sensor 300 is subsequently de-energized and transistor Tr1 is turned OFF, transistor Tr2 remains ON.

[0144] When a control signal (power OFF signal) is input from the control circuit 700 to the base of the transistor Tr4, the transistor Tr4 is turned on.

[0145] When transistor Tr4 is turned on, current flows through resistor R6 (which has a resistance value significantly smaller than that of resistor R5), causing the voltage applied to resistor R8, i.e., the voltage between the base and emitter of transistor Tr2, to become lower than the threshold voltage (e.g., 0.6 V), causing transistor Tr2 to turn off.

[0146] When the transistor Tr2 is turned off, the base current of the transistor Tr3 becomes zero, and the transistor Tr3 is turned off, thereby stopping the power supply to the control circuit 700.

[0147] As described above, when an impact (acceleration) equal to or greater than the minimum acceleration is applied, the impact sensor 300 enters a conducting state and conducts electricity, and when the absolute value of the applied acceleration subsequently decreases and falls below the minimum acceleration, the impact sensor 300 enters a non-conducting state and cuts off the conduction of electricity.

[0148] Therefore, if the electronic tag 100 is configured so that power is supplied to the control circuit 700 and memory 900 only while the impact sensor 300 is energized, there is a possibility that the supply of power to the control circuit 700 and memory 900 will be stopped before the control circuit 700 has finished writing the time to the memory 900. In this case, the time when the impact sensor 300 detected the impact cannot be recorded in the memory 900.

[0149] In contrast to this, in this embodiment, by providing the latch circuit 600, the supply of power to the control circuit 700 and memory 900 is maintained until the control circuit 700 completes writing the time to the memory 900. After the control circuit 700 completes writing the time to the memory 900, the latch circuit 600 goes into the OFF state, thereby stopping power consumption by the latch circuit 600, control circuit 700, and memory 900. This makes it possible to suppress consumption of the battery 400 while preventing the occurrence of a failure in which the impact sensor 300 is unable to record the time at which it detected an impact.

[0150] In this embodiment, the series circuit of resistors R1 and R2 that supplies power from the battery 400 to the impact sensor 300 constitutes a part of the latch circuit 600.

[0151] Therefore, when the impact sensor 300 detects an impact, it turns on and the latch circuit 600 activates, supplying power to the control circuit 700. In other words, the current flowing through the series circuit of resistors R1 and R2 functions as a detection signal indicating that the impact sensor 300 has detected an impact.

[0152] This eliminates the need to separately send a detection signal from the shock sensor 300 to the latch circuit 600. Therefore, compared to when the latch circuit 600 is activated by separately sending a detection signal from the shock sensor 300 to the latch circuit 600, the time lag between when the shock sensor 300 detects an impact and when the latch circuit 600 supplies power to the control circuit 700 can be reduced. This also reduces the time lag between when the control circuit 700 obtains the time from the RTC 500, thereby increasing the reliability of the time stored in the memory 900. Furthermore, the time until the latch circuit 600 switches to the OFF state is shortened, thereby reducing consumption of the battery 400.

[0153] [Operation procedure for electronic tag 100] FIG. 9 is a flowchart showing the operation flow of the electronic tag 100.

[0154] In step S01, an impact (acceleration) whose absolute value is equal to or greater than the minimum acceleration is applied to the electronic tag 100 (impact sensor 300).

[0155] In step S02, the impact sensor 300 is put into an energized state and energized.

[0156] In step S03, the latch circuit 600 is turned on and power is supplied from the latch circuit 600 to the control circuit 700 and the memory 900.

[0157] In step S04, the control circuit 700 acquires the time from the RTC 500.

[0158] In step S05, the control circuit 700 writes the acquired time into the memory 900.

[0159] In step S06, the control circuit 700 outputs a control signal (power OFF signal) to the latch circuit 600.

[0160] In step S07, the latch circuit 600 is turned off, and the supply of power from the latch circuit 600 to the control circuit 700 and the memory 900 is stopped.

[0161] [How to use the 100 electronic tags] FIG. 10 is a diagram for explaining how to use the electronic tag 100. In FIG.

[0162] In step (1), the electronic tag 100 is attached to a portable object 910. The portable object 910 is any of a variety of objects that can be transported and to which the electronic tag 100 can be attached.

[0163] The electronic tag 100 may be attached to the portable item 910 with, for example, double-sided tape, or may be attached to the portable item 910 with a dedicated jig or the like.

[0164] In step (2), an impact is applied to the portable item 910 to which the electronic tag 100 is attached. The electronic tag 100 stores in the memory 900 the time when the impact sensor 300 detects the impact.

[0165] When the electronic tag 100 detects an impact multiple times, it stores in the memory 900 all of the times at which the impacts were detected.

[0166] In step (3), the information stored in the memory 900 is read using the reader / writer 920.

[0167] [Effects of this embodiment] The impact sensor 300 of this embodiment includes a stator (frame portion 1) including a detection electrode 3, and a movable element including a movable electrode 2 and capable of being displaced upon receiving an external impact; the movable element is supported by the stator via a first elastic body (spring portion 4), and upon receiving an impact, causes the first elastic body (spring portion 4) to expand and contract, bringing the movable electrode 2 into contact with the detection electrode 3; the impact sensor 300 detects an impact by detecting the electrical connection between the movable electrode 2 and the detection electrode 3 when the movable electrode 2 comes into contact with the detection electrode 3; the detection electrode 3 is supported so that its entirety can be displaced in accordance with the displacement of the movable electrode 2 while in contact with the movable electrode 2.

[0168] With the above configuration, the detection electrode 3 is displaced as a whole in response to the movement of the movable electrode (movable electrode 2), allowing the contact time between the movable electrode 2 and the detection electrode 3 to be extended, and the circuit (latch circuit 600) that detects contact between the movable electrode 2 and the detection electrode 3 can be set to respond at a low frequency. This reduces the frequency of false detection of noise as an impact signal, and also makes it possible to keep the power consumption of the circuit low. Furthermore, since the detection electrode 3 is displaced as a whole in response to the movement of the movable electrode (movable electrode 2), the impact when the movable electrode (movable electrode 2) and the detection electrode 3 come into contact can be reduced, thereby suppressing damage and wear even if the movable electrode (movable electrode 2) and the detection electrode 3 repeatedly come into contact with each other, improving durability.

[0169] In this embodiment, the detection electrode 3 is supported by the stator (frame portion 1) via the second elastic body (second member 35A, second member 35B), and displaces in the displacement direction of the movable electrode 2 while deforming the second elastic body (second member 35A, second member 35B) while in contact with the movable electrode 2 from the position of the detection electrode 3 when the movable electrode 2 contacts the detection electrode 3.

[0170] With the above configuration, the second elastic body (second members 35A and 35B) receives force from the movable element (movable electrode 2) and deforms, so that the entire detection electrode 3 can be displaced. Therefore, a configuration that extends the contact time between the movable electrode 2 and the detection electrode 3 can be easily constructed.

[0171] In this embodiment, either the movable electrode 2 or the detection electrode 3 includes a first recess 21 whose depth direction is perpendicular to the displacement direction, and the other of the movable electrode 2 or the detection electrode 3 includes a first convex portion (for example, the convex shape of the contact electrode 33) at least a portion of which is accommodated in the first recess 21, and when the movable electrode 2 is displaced, the first convex portion and the first recess 21 come into contact with each other, and the movable electrode 2 and the detection electrode 3 come into contact, thereby detecting an impact.

[0172] With the above configuration, contact between the movable electrode 2 and the contact electrode 33 can be detected with a simple configuration.

[0173] In this embodiment, the first convex portion is disposed on the detection electrode 3, and the first concave portion is disposed on the movable electrode 2.

[0174] With the above configuration, it is possible to suppress rotation of the movable electrode 2 when it receives an impact (inertial force).

[0175] In this embodiment, a pair of first elastic bodies (spring portions 4L and 4R) are arranged to sandwich the movable electrode 2 from both sides in the displacement direction of the movable electrode 2.

[0176] With the above configuration, displacement in directions other than the direction sandwiching the movable electrode 2 is suppressed, so that an impact in a specific direction can be detected with high accuracy.

[0177] In this embodiment, a pair of second elastic bodies (second members 35A and 35B) are arranged so as to sandwich the contact electrode 33 from both sides in the displacement direction of the movable electrode 2.

[0178] With the above configuration, even if the second elastic body (second member 35A, second member 35B) is deformed (elastically deformed), the orientation of the contact electrode 33 does not change. Therefore, it is possible to reduce the change in the contact state between the movable electrode 2 and the contact electrode 33 when the movable electrode 2 presses the contact electrode 33, thereby enabling highly accurate detection of an impact.

[0179] In this embodiment, a first fixed electrode 11 is arranged on the stator (frame portion 1), and the second elastic body (second member 35A, second member 35B) is a beam portion including fixed ends (first fixed end, second fixed end) fixed to the first fixed electrode 11 and movable ends (first movable end, second movable end) connected to the detection electrode 3 and arranged in a direction intersecting the displacement direction, and the beam portion is deformed when the movable ends are displaced in the displacement direction.

[0180] With the above configuration, the second elastic body (second member 35A, second member 35B) can be constructed with a simple configuration.

[0181] In this embodiment, a first fixed electrode 11 is arranged on the stator (frame portion 1), the detection electrode 3 includes a contact electrode 33 in contact with the movable electrode 2 and a first member 34 extending from the contact electrode 33 in a direction along the displacement direction, the second elastic body (second member 35A, second member 35B) includes a pair of second members (second member 35A, second member 35B) extending from both ends of the longitudinal direction of the first member 34 in a direction intersecting the displacement direction and connected to the first fixed electrode 11, and the contact electrode 33 is connected to the first fixed electrode 11 via the first member 34 and the second members (second member 35A, second member 35B). The first member 34 is electrically connected to the electrode 11, and when it receives a force from the movable electrode 2 in a direction along the displacement direction via the contact electrode 33, it displaces in that displacement direction, and the second member (second member 35A, second member 35B) has its connection position with the first fixed electrode 11 as a fixed end (first fixed end, second fixed end) and its connection position with the first member 34 as a movable end (first movable end, second movable end), and when the movable ends (first movable end, second movable end) receive a force from the first member 34, it deforms in such a manner that the fixed ends (first fixed end, second fixed end) do not displace but the movable ends (first movable end, second movable end) are displaced.

[0182] With the above configuration, the detection electrode 3 including the contact electrode 33 that displaces in parallel with the movable electrode 2 can be constructed with a simple configuration.

[0183] In this embodiment, the stator (frame 1) is a rectangular frame 1, and the frame 1 includes a first beam 141 including a contact electrode 33, a second beam 142 connected to one end of the first beam 141 in the longitudinal direction and intersecting the first beam 141, a third beam 143 connected to the other end of the first beam 141 in the longitudinal direction and arranged opposite to and parallel to the second beam 142, and a third beam 143 connecting an end of the second beam 142 opposite to the end connected to the first beam 141 in the longitudinal direction and an end of the third beam 143 opposite to the end connected to the first beam 141 in the longitudinal direction. The frame portion 1 includes a fourth beam 144, and a first slit 151 is disposed on the inner peripheral side of the first beam 141, extending along the longitudinal direction of the first beam 141, and extending to a connection position between the first beam 141 and the second beam 142 and a connection position between the first beam 141 and the third beam 143. The second beam 142 is disposed with a second slit 152 extending from an end of the first slit 151 on the second beam 142 side to a midpoint in the longitudinal direction of the second beam 142. The third beam 143 is disposed with a second slit 152 extending from an end of the first slit 151 on the third beam 143 side to a midpoint in the longitudinal direction of the third beam 143. A third slit 153 is arranged extending to a middle position, and the first member 34 forms a portion of the first beam 141 from the first slit 151 to the inner periphery of the frame 1 and is integral with the contact electrode 33. One of the pair of second members (second member 35A) forms a portion of the first beam 141 from the second slit 152 to the inner periphery of the frame 1, and has a first fixed end at a connection position with the frame 1 and a first movable end at a connection position with the first member 34, and is deformed in such a manner that the first movable end is displaced relative to the first fixed end by receiving a force from the first member 34. The other of the pair of second members (second member 35B) forms a portion of the first beam 141 from the first slit 152 to the inner periphery of the frame 1, and has a first fixed end at a connection position with the frame 1 and a first movable end at a connection position with the first member 34. The first fixed electrode 11 is a portion that is on the inner periphery side of the frame portion 1 from the slit 153, and the connection position with the frame portion 1 is the second fixed end, and the connection position with the first member 34 is the second movable end, and when it receives a force from the first member 34, it deforms in such a manner that the second movable end is displaced relative to the second fixed end, and the first fixed electrode 11 is arranged in the frame portion 1 so as to surround the slit that combines the first slit 151, the second slit 152, and the third slit 153, and is connected to the second member (second member 35A, second member 35B), and when the contact electrode 33 receives a force from the movable electrode 2 toward the second beam 142,One of the pair of second members (second member 35A) deforms so that the first movable end is displaced in a direction narrowing the width of the second slit 152, and the other of the pair of second members (second member 35B) deforms so that the second movable end is displaced in a direction widening the width of the third slit 153, and when the contact electrode 33 receives a force from the movable electrode 2 toward the third beam 143, one of the pair of second members (second member 35A) deforms so that the first movable end is displaced in a direction widening the width of the second slit 152, and the other of the pair of second members (second member 35B) deforms so that the second movable end is displaced in a direction narrowing the width of the third slit 153.

[0184] With the above configuration, the detection electrode 3 (contact electrode 33, first member 34) and the second elastic body (second member 35A, second member 35B) can be formed by forming slits (first slit 151, second slit 152, third slit 153) in the stator (frame portion 1), so the detection electrode 3 (contact electrode 33, first member 34) and the second elastic body (second member 35A, second member 35B) can be constructed through a simple manufacturing process.

[0185] In this embodiment, the first member 34 and the pair of second members (second member 35A, second member 35B) are arranged in mirror symmetry about a line that is perpendicular to the displacement direction and passes through the contact electrode 33 (the center position of the displacement direction of the contact electrode 33).

[0186] With the above configuration, it is possible to make the reliability of impact detection in the two displacement directions of the movable electrode 2 the same.

[0187] In this embodiment, a first fixed electrode 11 electrically connected to the detection electrode 3 is arranged on the stator (frame portion 1), and one of the portion of the stator (frame portion 1) different from the first fixed electrode 11 and the movable electrode 2 includes a second recess 22 whose depth direction is perpendicular to the displacement direction, and the other portion of the stator (frame portion 1) different from the first fixed electrode 11 and the movable electrode 2 includes a second convex portion 121 whose at least a portion is accommodated in the second recess 22, and the distance (D2) in the displacement direction between the second convex portion 121 and the second recess 22 is set wider than the distance (D1) in the displacement direction between the first convex portion (contact electrode 33) and the first recess 21.

[0188] With the above configuration, the second convex portion 121 and the second concave portion 22 do not interfere with the contact between the first convex portion (contact electrode 33) and the first concave portion 21, and the displacement of the movable electrode 2 is stopped when the movable electrode 2 has displaced by the distance (D2) between the second convex portion 121 and the second concave portion 22, thereby reducing damage caused by impact to the movable parts of the impact sensor 300.

[0189] In this embodiment, a first recess 21 and a second recess 22 are arranged on the movable electrode 2, a first convex portion (the contact electrode 33 and the first convex portion are integrated) is arranged on the contact electrode 33, and a second convex portion 121 is arranged on the stator (frame portion 1).

[0190] With the above configuration, it is possible to suppress rotation of the movable electrode 2 when it receives an impact (inertial force).

[0191] In this embodiment, the first convex portion and the second convex portion 121 are arranged on the movable electrode 2, the first concave portion 21 is arranged on the contact electrode 33, and the second concave portion 22 is arranged on the stator (frame portion 1).

[0192] With the above configuration, a portion of the movable electrode 2 is housed in the contact electrode 33 and the stator (frame portion 1), and therefore electrical noise in the movable electrode 2 can be reduced accordingly.

[0193] In this embodiment, the stator (frame portion 1), the movable member (movable electrode 2), the first elastic body (spring portion 4), and the second elastic body (second member 35A, second member 35B) are an integral body, and the integral body is formed from a laminate in which an active layer 1c is stacked on a support layer (silicon substrate 1a, insulating layer 1b). The portion relating to the stator (frame portion 1) of the integral body is formed from the laminate, and the portion relating to the movable member (movable electrode 2), the first elastic body (spring portion 4), and the second elastic body (second member 35A, second member 35B) of the integral body is formed from the active layer 1c obtained by removing the support layer (silicon substrate 1a, insulating layer 1b) from the laminate.

[0194] With the above configuration, the impact sensor 300 can be formed by etching the stacked body (SOI wafer), and the impact sensor 300 can be easily manufactured in large quantities.

[0195] In this embodiment, the stator (frame portion 1) is provided with a first fixed electrode 11 electrically connected to the detection electrode 3 and a second fixed electrode 12 insulated from the first fixed electrode 11, and the second fixed electrode 12 is electrically connected to the movable electrode 2 by extending to the first elastic body (spring portion 4).

[0196] With the above configuration, a configuration in which the second fixed electrode 12 and the first fixed electrode 11 are electrically connected by contact between the movable electrode 2 and the contact electrode 33 can be easily set.

[0197] Although the present embodiment has been described above, the above embodiment merely shows one application example of the present invention, and is not intended to limit the technical scope of the present invention to the specific configuration of the above embodiment. [Explanation of symbols]

[0198] 300 Impact Sensor 1 Frame 1a Silicon substrate 1b Insulating layer 1c active layer 1d support frame 11 1st fixed electrode 12 Second fixed electrode 121 Second convex part 13 Groove 141 First Beam 142 Second Beam 143 Third Beam 144 Fourth Beam 151 First Slit 152 Second Slit 153 Third Slit 2 Movable electrode 21 First recess 22 Second recess 3. Detection electrode 33 Contact electrode 34 First member 35A 35B Second member 4 4L 4R Spring part 5 Mounting board 51 Pad electrode 52 Wire 100 Electronic Tags 200 Tag Body 300 Impact Sensor 400 batteries 500 RTC 600 Latch Circuit 700 Control Circuit 800 Antenna 900 memory 910 Transportable items 920 Reader / Writer

Claims

1. a stator including a sensing electrode; a mover that includes a movable electrode and is displaceable upon receiving an external impact, the movable element is supported by the stator via a first elastic body, and receives the impact to expand and contract the first elastic body, bringing the movable electrode into contact with the detection electrode; and the impact sensor detects the electrical connection between the movable electrode and the detection electrode when the movable electrode comes into contact with the detection electrode, The detection electrode is supported in contact with the movable electrode so as to be displaceable as a whole in response to displacement of the movable electrode.

2. 2. The impact sensor according to claim 1, wherein the detection electrode is supported by the stator via a second elastic body, and displaces in the displacement direction of the movable electrode while deforming the second elastic body while in contact with the movable electrode from the position of the detection electrode when the movable electrode contacts the detection electrode.

3. one of the movable electrode and the detection electrode includes a first recess having a depth direction perpendicular to the displacement direction; the other of the movable electrode and the detection electrode includes a first protrusion at least part of which is accommodated in the first recess; 3. The impact sensor according to claim 2, wherein the movable electrode is displaced so that the first convex portion and the first concave portion come into contact with each other, and the movable electrode comes into contact with the detection electrode, thereby detecting the impact.

4. the first protrusion is disposed on the detection electrode, The impact sensor according to claim 3 , wherein the first recess is disposed in the movable electrode.

5. 2. The impact sensor according to claim 1, wherein the first elastic bodies are arranged in pairs so as to sandwich the movable electrode from both sides in the displacement direction of the movable electrode.

6. 3. The impact sensor according to claim 2, wherein the second elastic bodies are arranged in pairs so as to sandwich the detection electrode from both sides in the displacement direction of the movable electrode.

7. a first fixed electrode is disposed on the stator; 3. The impact sensor according to claim 2, wherein the second elastic body is a beam portion including a fixed end fixed to the first fixed electrode and a movable end connected to the detection electrode and arranged in a direction intersecting the displacement direction, and the beam portion is deformed when the movable end is displaced in the displacement direction.

8. a first fixed electrode is disposed on the stator; The detection electrode is a contact electrode in contact with the movable electrode; a first member extending from the contact electrode in a direction along the displacement direction, The second elastic body is a pair of second members extending from both ends of the first member in a longitudinal direction in a direction intersecting the displacement direction and connected to the first fixed electrode; The contact electrode is electrically connected to the first fixed electrode via the first member and the second member; The first member is When a force is applied from the movable electrode via the contact electrode in a direction along the displacement direction, the movable electrode is displaced in the displacement direction. The second member is 3. The impact sensor according to claim 2, wherein the connection position with the first fixed electrode is a fixed end, the connection position with the first member is a movable end, and when the movable end receives a force from the first member, the fixed end is not displaced but the movable end is displaced.

9. The stator is a rectangular frame, the frame portion includes a first beam including the contact electrode; a second beam connected to one end of the first beam in the longitudinal direction and intersecting the first beam; a third beam connected to the other end of the first beam in the longitudinal direction and disposed opposite and parallel to the second beam; a fourth beam connecting an end of the second beam opposite to an end connected to the first beam in the longitudinal direction and an end of the third beam opposite to an end connected to the first beam in the longitudinal direction, a first slit is disposed on an inner peripheral side of the frame portion of the first beam, the first slit extending along a longitudinal direction of the first beam and extending to a connection position between the first beam and the second beam and a connection position between the first beam and the third beam; a second slit is disposed in the second beam, the second slit extending from an end of the first slit on the second beam side to a midpoint in the longitudinal direction of the second beam; a third slit is disposed in the third beam, the third slit extending from an end of the first slit on the third beam side to a midpoint in the longitudinal direction of the third beam; The first member is a portion of the first beam extending from the first slit to the inner periphery of the frame portion and integral with the contact electrode; one of the pair of second members is a portion that is on the inner peripheral side of the frame portion from the second slit, has a first fixed end at a connection position with the frame portion and a first movable end at a connection position with the first member, and is deformed in a manner such that the first movable end is displaced relative to the first fixed end by receiving a force from the first member; the other of the pair of second members is a portion that is on the inner peripheral side of the frame portion from the third slit, has a second fixed end at a connection position with the frame portion and a second movable end at a connection position with the first member, and is deformed in a manner such that the second movable end is displaced relative to the second fixed end by receiving a force from the first member; the first fixed electrode is disposed in the frame portion so as to surround a slit formed by integrating the first slit, the second slit, and the third slit, and is connected to the second member; when the contact electrode receives a force from the movable electrode toward the second beam, one of the pair of second members deforms so that the first movable end is displaced in a direction narrowing the width of the second slit, and the other of the pair of second members deforms so that the second movable end is displaced in a direction widening the width of the third slit, 9. The impact sensor of claim 8, wherein when the contact electrode receives a force from the movable electrode toward the third beam, one of the pair of second members deforms so that the first movable end is displaced in a direction widening the width of the second slit, and the other of the pair of second members deforms so that the second movable end is displaced in a direction narrowing the width of the third slit.

10. 10. The impact sensor according to claim 8, wherein the first member and the pair of second members are arranged in mirror symmetry with respect to a line that is perpendicular to the displacement direction and passes through the contact electrodes.

11. a first fixed electrode electrically connected to the detection electrode is disposed on the stator; one of the portion of the stator different from the first fixed electrode and the movable electrode includes a second recess having a depth direction perpendicular to the displacement direction, the other of the portion of the stator different from the first fixed electrode and the movable electrode includes a second protrusion at least part of which is accommodated in the second recess, 4. The impact sensor according to claim 3, wherein a distance between the second convex portion and the second concave portion in the displacement direction is set wider than a distance between the first convex portion and the first concave portion in the displacement direction.

12. 12. The impact sensor according to claim 11, wherein the first recess and the second recess are arranged on the movable electrode, the first protrusion is arranged on the detection electrode, and the second protrusion is arranged on the stator.

13. 12. The impact sensor according to claim 11, wherein the first convex portion and the second convex portion are arranged on the movable electrode, the first concave portion is arranged on the detection electrode, and the second concave portion is arranged on the stator.

14. the stator, the movable element, the first elastic body, and the second elastic body are an integral body, and the integral body is formed from a laminate in which an active layer is laminated on a support layer, a portion of the integrated body relating to the stator is formed by the laminated body, 3. The impact sensor according to claim 2, wherein the portion of the integrated body relating to the mover, the first elastic body, and the second elastic body is formed by the active layer obtained by removing the support layer from the laminate.

15. the stator has a first fixed electrode electrically connected to the detection electrode; a second fixed electrode insulated from the first fixed electrode; 2. The impact sensor according to claim 1, wherein the second fixed electrode extends to the first elastic body and is electrically connected to the movable electrode.

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