A micro inertial switch with online detection function

Abstract

The present invention relates to the field of sensor technology, and discloses a micro inertial switch with an online detection function. The micro inertial switch is provided with a first electrode plate and a second electrode plate on the upper side of a mass block of a first structural layer and on the lower side of a second structural layer to form a detection capacitor group. By detecting the capacitance of the detection capacitor group, the spacing distance or the change of the facing area between the first electrode plate and the second electrode plate can be understood, and then the movement of the mass block under the action of acceleration can be understood, thereby realizing the dynamic characteristic test of the micro inertial switch. The capacitance signal of the detection capacitor group is only led out through one or more groups of terminal groups arranged on the second structural layer, and the first electrode plate on the mass block does not need additional leads, which simplifies the manufacturing process. In addition, since the first electrode plate arranged on the mass block is not directly energized, the mass block can be undisturbed during the dynamic characteristic test. Therefore, the motion characteristics of the sensitive structure mass block can be tested during the normal operation of the micro inertial switch.

Description

Technical Field

[0001] The present invention relates to the field of sensor technology, in particular to a micro inertial switch, and in particular to a micro inertial switch with an online detection function. Background Art

[0002] Micro inertial switches generally include active contacts and fixed contacts. When the acceleration of the sensitive structure reaches the action threshold, the active contacts and fixed contacts come into contact and conduct. Micro inertial switches often require dynamic characteristic testing during the manufacturing process. This test is crucial for understanding the movement of the internal mass block during its operation, obtaining the dynamic parameters of the sensitive structure, and analyzing the working performance of the micro inertial switch.

[0003] The dynamic characteristics test of MEMS devices in the industry often adopts optical or imaging principles, such as laser Doppler vibrometer, laser automatic hybrid interferometer, high-speed camera, etc. However, the optical or imaging principle test method requires light to be able to reach the microstructure components or be able to directly observe the microstructure components, so it can only be tested at the chip level when the microstructure is not packaged. Micro inertial switches are small in size, and it is difficult to use instruments and equipment to test their dynamic characteristics. In addition, when the micro inertial switch is packaged, its dynamic characteristics can no longer be obtained through existing dynamic characteristics testing methods. Summary of the invention

[0004] In order to solve the above technical problems, the present invention provides a micro inertial switch with an online detection function, so that the packaged micro inertial switch can perform dynamic characteristic testing by measuring the capacitance change of the detection capacitor group.

[0005] The present invention provides a micro inertial switch with an online detection function, comprising a first structural layer, a second structural layer, a fixed contact, a movable contact, at least one group of detection capacitors, and a terminal group adapted to the number of detection capacitors. A mass block suspended by a flexible beam and movable in the direction of acceleration is formed in the first structural layer, and the movable contact is arranged on the mass block; under the action of acceleration, the mass block can drive the movable contact to move in the direction of acceleration so that the movable contact is in contact with the fixed contact. Each group of detection capacitors includes two pairs of first and second plates arranged oppositely, and the first structural layer and the second structural layer are stacked; one side of the first structural layer close to the second structural layer is provided with two first plates of the detection capacitor group electrically connected to each other, and the two first plates are electrically isolated from the movable contact; one side of the second structural layer close to the first structural layer is provided with two second plates of the detection capacitor group independent of each other, and the two second plates are respectively coupled to the first and second terminals of a group of terminal groups arranged in the second structural layer. The mass block can move in the direction of acceleration under the action of acceleration to change the spacing distance or facing area between the corresponding first and second plates.

[0006] In some embodiments, the micro inertial switch further comprises a third structural layer, the third structural layer is arranged on a side of the first structural layer away from the second structural layer, and the fixed contacts are configured as two, and the two fixed contacts are arranged on a side of the third structural layer close to the first structural layer. Wherein, the acceleration direction is the height direction, and the mass block can move in the height direction under the action of the acceleration to change the spacing distance between the corresponding first electrode plate and the second electrode plate. In particular, the two first electrode plates of each detection capacitor group are constructed as a whole, and the two second electrode plates are located in the same plane and can be completely projected onto the first electrode plate.

[0007] Optionally, the mass block is configured in a circular shape, the micro inertial switch includes four detection capacitor groups and four terminal groups, the four detection capacitor groups are arranged circumferentially on the mass block, and the two second electrodes of each detection capacitor group are respectively coupled to the first terminal and the second terminal of a terminal group. The two first electrodes of each detection capacitor group form a whole configured in a 1 / 4 circle sector, and the second electrode of each detection capacitor group is configured in a 1 / 8 circle sector.

[0008] Optionally, the mass block is configured in a rectangular shape, the micro inertial switch includes four detection capacitor groups and four terminal groups, the four detection capacitor groups are distributed at four corners of the mass block to form two rows and two columns, and the two second electrodes of each detection capacitor group are respectively coupled to a first terminal and a second terminal of a terminal group. The second electrodes of the four detection capacitor groups are arranged in four rows and two columns, and the four terminals are arranged in two columns.

[0009] Furthermore, one side of the third structure layer protrudes from the second structure layer, and two leads are provided on one side of the third structure layer close to the first structure layer. The two leads are electrically connected to a fixed contact respectively, and the two leads extend to the protruding part of the third structure layer.

[0010] Features and advantages of the present disclosure include:

[0011] The micro inertial switch disclosed in the present invention respectively arranges a first electrode plate and a second electrode plate on the upper side of the mass block of the first structural layer and on the lower side of the second structural layer to form a detection capacitor group. By detecting the capacitance of the detection capacitor group, the spacing distance or the change of the facing area between the first electrode plate and the second electrode plate can be understood, and then the movement of the mass block under the action of acceleration can be understood, thereby realizing the dynamic characteristic test of the micro inertial switch.

[0012] The capacitance signal of the detection capacitor group is only led out through one or more groups of terminal blocks arranged on the second structure layer, and the first electrode plate on the mass block does not need additional leads, which simplifies the manufacturing process. In addition, since the first electrode plate arranged on the mass block is not directly energized, the mass block can be undisturbed during the dynamic characteristic test, so the motion characteristics of the sensitive structure mass block can be tested during the normal operation of the micro inertial switch. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0014] Figure 1 A schematic structural diagram of a micro inertial switch with an online detection function of the present invention is shown, wherein the acceleration direction is out of the plane;

[0015] Figure 2 Shows Figure 1 A schematic longitudinal section view of a micro inertial switch;

[0016] Figure 3 Shows Figure 1 A schematic diagram of the structure of the fixed contacts and the movable contacts of the micro inertial switch;

[0017] Figure 4 Shows Figure 1 A schematic structural diagram of a first electrode plate and a second electrode plate of an embodiment of a micro inertial switch;

[0018] Figure 5A Shows Figure 1 Schematic diagram of the principle of online testing of dynamic characteristics of micro inertial switches;

[0019] Figure 5B Shows Figure 5A Equivalent schematic diagram of the detection capacitor bank;

[0020] Figure 6 A schematic diagram of the structure of another micro inertial switch with online detection function of the present invention is shown, wherein the acceleration direction is out of the plane;

[0021] Figure 7 Shows Figure 6 A schematic structural diagram of a first electrode plate and a second electrode plate of an embodiment of a micro inertial switch in FIG. 1 , wherein the mass block is configured in a circular shape;

[0022] Figure 8 Shows Figure 6A schematic structural diagram of a first pole plate and a second pole plate of another embodiment of a micro inertial switch, wherein the mass block is configured as a rectangle;

[0023] Fig. 9 A schematic structural diagram of another micro inertial switch with online detection function of the present invention is shown, wherein the acceleration direction is in-plane;

[0024] Fig.10 Shows Fig. 9 A schematic cross-sectional view of a micro inertial switch;

[0025] Fig.11 Shows Fig. 9 A schematic diagram of the structure of the fixed contacts and the movable contacts of the micro inertial switch;

[0026] Fig.12 Shows Fig. 9 A schematic diagram of the structure of the first electrode plate and the second electrode plate of the micro inertial switch;

[0027] Fig.13A Shows Fig. 9 Schematic diagram of the principle of online testing of dynamic characteristics of micro inertial switches;

[0028] Fig. 13B Shows Fig.13A Equivalent schematic diagram of the detection capacitor bank.

[0029] Description of reference numerals:

[0030] 100- micro inertial switch, 101- movable contact, 102- fixed contact, 103- lead, 104- wiring area, 106- bonding frame;

[0031] 10-first structural layer, 12-mass block, 14-flexible beam, 16-frame, 20-second structural layer, 30-third structural layer;

[0032] 40 - detection capacitor bank, 42 ​​- first plate, 42a - first sub-plate, 44 - second plate, 44a - second sub-plate;

[0033] 50-connection terminal group, 52-first connection terminal, 54-second connection terminal;

[0034] 62 - height direction, 63 - first direction, 64 - second direction. DETAILED DESCRIPTION

[0035] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0036] See also Figures 1 to 12 The present invention discloses a micro inertial switch with online detection function, comprising a first structural layer 10, a second structural layer 20, a fixed contact 102, a movable contact 101, at least one group of detection capacitor groups 40, and at least one group of terminal groups 50, wherein the number of terminal groups 50 is the same as the number of detection capacitor groups 40. The first structural layer 10 and the second structural layer 20 are stacked, and a mass block 12 that can move along the acceleration direction and is suspended by a flexible beam 14 is formed in the first structural layer 10, and the movable contact 101 is arranged on the mass block 12. The fixed contact 102 is arranged at the fixed part of the micro inertial switch 100, for example, arranged at Figure 1 and Figure 2 The third structural layer 30 (to be described later) of the micro inertial switch 100 shown in FIG. Fig. 9 and Fig.10 The frame 16 surrounding the mass block 12 and the flexible beam 14 formed in the first structural layer 10 of the micro-inertial switch shown in the figure has a gap between the fixed contact 102 and the movable contact 101. Under the action of acceleration, the mass block 12 can drive the movable contact 101 to move along the acceleration direction so that the movable contact 101 and the fixed contact 102 are in contact and connected. In the natural state, the movable contact 101 and the fixed contact 102 are not in contact, and the micro-inertial switch is disconnected; when the action threshold is reached under the action of acceleration, the movable contact 101 and the fixed contact 102 are in contact, and the micro-inertial switch is closed.

[0037] Each detection capacitor group 40 includes two capacitors connected in series, each capacitor is provided with a first electrode plate 42 and a second electrode plate 44, that is, each detection capacitor group 40 includes two pairs of first electrode plates 42 and second electrode plates 44 arranged opposite to each other. Among them, the two first electrode plates 42 are electrically connected, and the two second electrode plates 44 are independently arranged (that is, the two second electrode plates 44 are not directly electrically connected), so that the two capacitors are connected in series. The terminal group 50 includes a first terminal 52 and a second terminal 54, and the two independent second electrode plates 44 are electrically connected to the first terminal 52 and the second terminal 54 respectively. Specifically, the mass block 12 is provided with two first electrode plates 42 of the detection capacitor group 40 that are electrically connected to each other on one side close to the second structural layer 20, wherein the two first electrode plates 42 are electrically isolated from the movable contact 101. A side of the second structural layer 20 close to the first structural layer 10 is provided with two independent second polar plates 44 of a detection capacitor group 40, and a terminal group 50 is arranged on the second structural layer 20. The two second polar plates 44 are respectively coupled to a first terminal 52 and a second terminal 54 of a terminal group arranged on the second structural layer.

[0038] Since the first electrode plate 42 is fixed to the mass block 12, it can move with the mass block 12, so the first electrode plate 42 is also a movable electrode plate. Similarly, the second electrode plate 44 is fixed to the second structure layer 20, and it is fixed together with the second structure layer 20, that is, the second electrode plate 44 is also a fixed electrode plate. Among them, the mass block 12 can move in the acceleration direction under the action of acceleration, thereby driving the first electrode plate 42 to move to change the spacing distance or facing area between the first electrode plate 42 and the second electrode plate 44. Specifically, Figures 1 to 8 An embodiment of the present disclosure for changing the spacing distance between the first electrode plate and the second electrode plate of the detection capacitor group under the action of acceleration is shown. Figures 9 to 13B An embodiment provided by the present disclosure of changing the facing area of ​​the first electrode plate and the second electrode plate of the detection capacitor group under the action of acceleration is shown.

[0039] The micro-inertial switch 100 provided by the present disclosure has the function of online detection of the dynamic characteristics of the micro-inertial switch without affecting its switch function. When acceleration acts, the real-time capacitance (i.e., capacitance value) of the detection capacitor group can be measured online, and the dynamic characteristics of the micro-inertial switch can be obtained by detecting the capacitance change of the capacitor group, thereby realizing online detection of the dynamic characteristics of the micro-inertial switch. Since the movable plate (first plate 42) of the detection capacitor group is arranged on the mass block (i.e., movable microstructure) of the micro-inertial switch, and the fixed plate (second plate 44) is arranged on the second structural layer, the change of the detection capacitor group reflects the displacement change of the movable microstructure, and the dynamic characteristics of the movable microstructure can be obtained by measuring the movement displacement of the movable microstructure.

[0040] See also Figures 1 to 5BThe present disclosure provides a micro inertial switch 100 with an online detection function, which is a micro inertial switch in which a mass block moves out of plane under the action of acceleration. The acceleration direction is the height direction 62 (i.e., out of plane), that is, under the action of acceleration, the spacing between the first plate and the second plate of the detection capacitor group can be changed to change the detection capacitance. Figure 1 , Figure 2 The micro inertial switch is provided with a second structural layer 20, a first structural layer 10 and a third structural layer 30 from top to bottom, and a mass block 12 suspended by a flexible beam 14 is formed in the first structural layer 10. The micro inertial switch has a cavity inside so that the mass block 12 can move up and down (swing) under the acceleration in the height direction 62. The material of the first structural layer 10 is a material suitable for preparing its structure, such as silicon, polycrystalline silicon, etc.; the material of the second structural layer 20 and the third structural layer 30 is silicon or glass, etc.

[0041] Specifically, the first structural layer 10 includes a mass block 12, a flexible beam 14 and a frame 16. The frame 16 is configured as a closed annular frame, the outer contour of the frame 16 is configured as a square, and the inner contour is configured as a figure that is indented inward and similar to the outer contour. The mass block 12 and the flexible beam 14 are arranged in the internal cavity formed by the frame 16, and the mass block 12 is connected to the frame 16 through the flexible beam 14. Specifically, the flexible beam 14 can be configured as a cantilever straight beam, a folded beam, a U-shaped beam or a spiral beam, etc., and the form is not limited. In terms of quantity, a single or multiple flexible beams 14 can be provided to support the mass block 12. Preferably, the flexible beam 14 is configured as two, symmetrically arranged on opposite sides of the mass block 12, such as Figure 2 The shape of the mass block 12 can be configured into any shape suitable for being accommodated in the frame 16, see Figure 7 , Figure 8 , such as a circle or a rectangle. The first structure layer 10 can be made of a common silicon wafer and shaped by etching.

[0042] Specifically, the micro inertial switch 100 can form a space for the mass block 12 to move in a variety of ways. In some embodiments, the thickness of the frame 16 is configured to be greater than the thickness of the mass block 12 to provide a space for the mass block 12 to move. In other embodiments, the thickness of the frame 16 can be equal to the thickness of the mass block 12, and a recess (not shown in the figure) can be formed in the middle of the second structural layer 20 and the third structural layer 30 facing the first structural layer 10 to provide a space for the mass block 12 to move; or see Figure 2The second structure layer 20 and the third structure layer 30 are configured as flat plates, and the bonding frame 106 is respectively provided between the first structure layer 10 and the second structure layer 20 and between the first structure layer 10 and the third structure layer 30 to provide a space for the mass block 12 to move. Optionally, the internal space of the micro inertial switch 100 can be formed by combining in a variety of ways. The following is an example of providing the bonding frame 106 on the upper and lower sides of the first structure layer 10.

[0043] Specifically, see Figure 2 , Figure 3 , a movable contact 101 is provided on the lower surface of the mass block 12, and two electrically isolated fixed contacts 102 are provided on one side of the third structural layer 30 close to the mass block 12. When the micro-inertial switch is in the disconnected state, the mass block 12 can move downward under the action of acceleration, so that the movable contact 101 is in contact with the fixed contact 102 and is connected, and the micro-inertial switch is closed; when the micro-inertial switch is in the closed state, when the movable contact 101 moves upward with the mass block 12, the movable contact 101 leaves the fixed contact 102, and the micro-inertial switch is disconnected. The movable contact 101 and the fixed contact 102 can be constructed in any shape and any number, and there is no specific limitation here, as long as they can be connected when in contact and disconnected when separated. Optionally, refer to Figure 3 , the movable contact 101 is formed into a rectangle, the two fixed contacts 102 are respectively formed into rectangles, and the two fixed contacts 102 are arranged in parallel and spaced apart along the first direction 63 (left-right direction). When the movable contact 101 is projected onto the plane of the fixed contacts 102, the projection of the movable contact 101 and the two fixed contacts 102 are at least partially overlapped, and the contour lines on the left and right sides of the movable contact 101 can be located within the two fixed contacts 102 (such as Figure 3 As shown), it may also be located outside the fixed contact (ie, the projection of the movable contact 101 covers the fixed contact 102).

[0044] More specifically, see Figure 1 , the third structural layer 30 is provided with two leads 103, each lead 103 is connected to a fixed contact 102, and the outside can be electrically connected to the micro inertial switch 100 through the lead 103. In particular, the third structural layer 30 protrudes from the first structural layer 10 along the second direction 64 (front-back direction), wherein the second direction 64 is parallel to the horizontal plane and perpendicular to the first direction 63. The two leads 103 are arranged on one side of the third structural layer 30 close to the first structural layer 10, and extend to the outside of the first structural layer 10 along the second direction 64, so that one end of the two leads 103 is exposed to the outside of the micro inertial switch 100, which is convenient for external connection.

[0045] In particular, the two first plates 42 of the detection capacitor group 40 can be constructed as a whole plate, which is convenient for production and manufacturing, and also makes the electrical connection of the two first plates 42 more reliable. The micro inertial switch 100 also includes a terminal group 50 adapted to the number of detection capacitor groups, each terminal group 50 includes a first terminal 52 and a second terminal 54, and each detection capacitor group 40 is electrically connected or electrically coupled to the outside through a terminal group 50.

[0046] Specifically, see Figure 2 , the terminal group 50 is arranged on the second structural layer 20, one end of the first terminal 52 and the second terminal 54 are electrically connected to the two second electrodes 44 respectively, and the external detection circuit is directly or indirectly connected to the other end of the first terminal 52 and the second terminal 54. The terminal group 50 is arranged through the second structural layer 20, and in particular, the terminal group 50 extends in the height direction. For example, the second structural layer 20 is provided with a through hole extending in the height direction, and the first terminal 52 and the second terminal 54 are respectively arranged in one through hole. Optionally, the outer surface of the second structural layer 20 (the side away from the first structural layer) is provided with two wiring areas 104 for external wiring, and the two wiring areas 104 are electrically connected to the first terminal 52 and the second terminal 54 respectively.

[0047] The first electrode plate 42 and the second electrode plate 44 of each detection capacitor group are both configured as flat plates. The outer contours of the first electrode plate 42 and the second electrode plate 44 can be configured into any suitable shape, such as a rectangle, a fan-shaped, etc., which is not specifically limited here, as long as two capacitors connected in series can be formed. In particular, the first electrode plate 42 and the second electrode plate 44 of each detection capacitor group are arranged in parallel, so that the spacing distance between the first electrode plate 42 and the second electrode plate 44 of the detection capacitor group is the same. Preferably, see Figure 4 , the plates of the two capacitors in each detection capacitor group have the same facing area, that is, when projected onto a horizontal plane, the overlapping area of ​​the projection of the first plate 42 and the projection of the second plate 44 of each capacitor is the same. More preferably, the spacing distance between the plates of the two capacitors is the same and the facing area is also the same, so that the capacitance of the two capacitors in each detection capacitor group can be equal.

[0048] Continue to see Figure 4, the whole (whole plate) formed by the two first plates 42 is configured as a rectangle, the two second plates 44 are configured as a rectangle, and the two second plates 44 are arranged in parallel along the first direction 63. Optionally, when the first plates 42 and the second plates 44 of each detection capacitor group are projected onto a horizontal plane, the projections of the two first plates 42 can respectively cover the projections of the corresponding second plates 44. In some embodiments, the outer contour of the projection of the whole (whole plate) formed by the two first plates 42 is located outside the outer contour of the projection of the two second plates 44.

[0049] It should be added that the materials of the movable contact 101, the fixed contact 102, the lead 103, the wiring area 104, the first electrode 42, the second electrode 44, the first terminal 52, and the second terminal 54 are all conductive materials, such as metal materials, and specifically can be one or more of nickel, gold, aluminum, etc. Optionally, an insulating layer can be provided on the first electrode 42 or the second electrode 44 to prevent the first electrode 42 from directly contacting the second electrode 44 when the mass 12 moves. The insulating layer can be formed by depositing silicon oxide on the first electrode 42 or the second electrode 44.

[0050] See also Figure 5A , the mass block 12 can move along the height direction 62, and the first electrode plate 42 can move with the mass block 12, that is, the first electrode plate 42 is the movable electrode plate of the detection capacitor group; and the second electrode plate 44 is arranged on the second structure layer 20, and is fixed together with the second structure layer 20, that is, the second electrode plate 44 is the fixed electrode plate of the detection capacitor group. One first electrode plate 42 and one second electrode plate 44 form a capacitor, and another first electrode plate 42 and another second electrode plate form another capacitor. The two capacitors are connected in series, and their equivalent circuit diagram is shown in FIG. Figure 5B The capacitance of the first capacitor is C1, the capacitance of the second capacitor is C2, and the equivalent capacitance after the series connection is Cout. Since 1 / Cout=1 / C1+1 / C2, we can get Cout=C1C2 / (C1+C2). When C1=C2, Cout=C1 / 2.

[0051] When the mass block 12 moves along the height direction 62 under the action of acceleration, the area facing the detection capacitor group remains unchanged, and the two first plates 42 move synchronously with the mass block in the height direction 62, so that the first plates of the two detection capacitor groups are close to or away from the second plates, that is, the spacing distance between the first plates and the second plates is changed. By measuring the equivalent capacitance Cout of the detection capacitor group, the change of the spacing distance between the first plates and the second plates can be obtained, thereby obtaining the movement of the mass block 12 (that is, obtaining the displacement of the mass block).

[0052] The three structural layers of the micro inertial switch 100 can be connected together by bonding, wherein the second structural layer is provided with the sensitive structure of the device (flexible beam-mass block), the second structural layer can protect the sensitive structure as a cover plate, and the third structural layer is arranged at the bottom to play a supporting and protective role, and can also lead out the switch contact signal electrode. A metal first electrode plate is prepared on the upper side of the mass block of the first structural layer, and a metal second electrode plate is prepared on the lower side of the second structural layer, forming a detection capacitor group for detecting the dynamic characteristics of the micro inertial switch 100, and the two capacitors in the detection capacitor group are connected in series. The second electrode plate located on the lower side of the second structural layer is connected to the wiring area 104 on the upper side of the second structural layer through a wiring terminal. When the micro inertial switch 100 is encapsulated in a tube shell, the wiring area 104 can be electrically connected to the internal pins of the tube shell through a lead. When the micro inertial switch 100 detects changes in the capacitance of the capacitor group under vibration impact mechanical excitation or during operation, the displacement of the out-of-plane motion of the sensitive structure of the MEMS device can be obtained. The detection capacitor group is electrically connected to the outside through the terminal group 50 arranged on the second structural layer 20 (that is, the terminal group 50 serves as a lead for electrically connecting the detection capacitor group to the outside). The first electrode 42 on the mass block 12 located on the first structural layer 10 does not need to be provided with a lead connected to the outside, which is conducive to simplifying the structural setting.

[0053] Specifically, when the dynamic characteristics of the micro-inertial switch are tested, the packaged micro-inertial switch is installed on the vibration table through the tooling, and sinusoidal vibrations of different frequencies are applied to perform frequency sweeps to test the change in equivalent capacitance Cout. The amplitude-frequency characteristic curve of the micro-inertial switch can be obtained, and the dynamic parameters such as the damping coefficient and resonant frequency of the micro-inertial switch can be obtained by analyzing the amplitude-frequency characteristic curve. It is also possible to test the change in equivalent capacitance Cout after applying an impact, obtain the displacement attenuation of the sensitive structure of the micro-inertial switch, and analyze the displacement attenuation curve of the sensitive structure to obtain the dynamic parameters of the micro-inertial switch.

[0054] In some embodiments, the micro-inertial switch 100 may be provided with a plurality of detection capacitor groups, such as two groups, three groups, four groups, etc., to more accurately understand the movement status of the mass block 12. When multiple detection capacitor groups are used, the movement posture of the sensitive structure in the working process of the micro-inertial switch can also be tested. When the sensitive structure (i.e., the mass block) of the first structural layer is displaced under the action of an external load or during the operation of the micro-inertial switch 100, the change in detection capacitance in different regions can be tested to obtain the displacement change curve of each region, and the movement posture of the sensitive structure (i.e., the mass block) of the micro-inertial switch can be obtained according to the displacement change curve of each region. Figures 6 to 8 The micro inertial switch 100 is provided with four detection capacitor groups and four terminal groups, each detection capacitor group is electrically connected to one terminal group. In particular, the upper surface of the second structural layer 20 is provided with eight wiring areas 104, each first wiring terminal and second wiring terminal is connected to one wiring area 104 respectively.

[0055] Specifically, see Figure 7 In some embodiments, the mass block 12 is configured in a circular shape, and four groups of detection capacitor groups 40 are circumferentially distributed on the mass block 12. The second electrode plate 44 of each group of detection capacitor groups is configured in a sector shape of about 1 / 8 of a circle (e.g., a sector shape of 1 / 8 of a circle), and the whole formed by the two first electrode plates 42 of each group of detection capacitor groups is configured in a sector shape of about 1 / 4 of a circle (a sector shape of 1 / 4 of a circle). In particular, in the horizontal projection, the projected outer contour of the mass block 12 is at the outermost side, and the projected outer contour of the whole (whole plate) formed by the two first electrode plates 42 of the detection capacitor group and the projected outer contour of the second electrode plate are successively indented inward, as shown in FIG. Figure 7 As shown. When viewed from above, eight capacitors are formed arranged counterclockwise, and their capacitances are C1 to C8. The equivalent capacitances of the four detection capacitor groups are Cout1, Cout2, Cout3, and Cout4, where Cout1 = C1C2 / (C1+C2), Cout2 = C3C4 / (C3+C4), Cout3 = C5C6 / (C5+C6), and Cout4 = C7C8 / (C7+C8).

[0056] Specifically, see Figure 8 In some embodiments, the mass block 12 is configured as a rectangle, and four detection capacitor groups 40 are distributed at the four corners of the mass block 12 to form two rows and two columns. The two first plates of each detection capacitor group are respectively coupled to a first terminal 52 and a second terminal 54 of a terminal group. The whole (whole plate) formed by the two first plates 42 is configured as a rectangle, and the second plate 44 is also configured as a rectangle. Preferably, continue to refer to Figure 8 , four whole bodies (whole plates) formed by two first plates 42 are arranged in two rows and two columns, and four sets of second plates 44 of detection capacitor groups are arranged in four rows and two columns, wherein two sets of terminal groups are located on one side of the second structural layer, and the other two sets of terminal groups are located on the other side of the second structural layer. In particular, in the horizontal projection, the projected outer contour of the mass block 12 is at the outermost side, and the projected outer contour of the whole body (whole plate) formed by the two first plates 42 of the detection capacitor group and the projected outer contour of the second plate 44 are successively indented inward, as shown in FIG. Figure 8 When viewed from above, eight capacitors arranged in an array are provided, and their capacitances are C1 to C8 in sequence, and the equivalent capacitances of the four detection capacitor groups formed are Cout1, Cout2, Cout3, and Cout4 in sequence.

[0057] See also Figures 9 to 13BThe present disclosure also provides a micro inertial switch 100, which is a micro inertial switch in which a mass block moves in a plane under the action of acceleration, that is, when the acceleration direction is parallel to the horizontal plane, the mass block moves in a plane under the action of acceleration, and the equivalent capacitance of the detection capacitor group is changed by changing the area facing the detection capacitor group under the action of acceleration. Figures 9 to 11 The micro inertial switch 100 is provided with a second structural layer 20, a first structural layer 10 and a third structural layer 30 from top to bottom, and a mass block 12 suspended by a flexible beam 14 is formed in the first structural layer 10. The micro inertial switch 100 has a cavity inside so that the mass block 12 can move in a plane under the action of acceleration. Specifically, Fig. 9 and Fig.10 The first structural layer 10 of the micro inertial switch 100 is Figure 1 and Figure 2 The first structural layer 10 of the micro inertial switch 100 shown is substantially the same, and only the flexible beam 14 needs to be adaptively adjusted based on the first structural layer 10 of the micro inertial switch 100, so that the mass 12 can move in the plane under the acceleration in the in-plane direction. Fig.10 The movable contact 101 is arranged on the side wall of the mass block 12, and the fixed contact 102 is arranged on the inner wall of the frame 16. When the mass block 12 moves in the plane under the action of acceleration, the movable contact 101 and the fixed contact 102 can be driven to contact and conduct, so that the micro inertial switch 100 is closed. When the movable contact 101 and the fixed contact 102 are separated, the micro inertial switch 100 is opened.

[0058] Preferably, the flexible beam 14 is configured as two, and the two flexible beams are arranged on opposite sides of the mass block 12, so that the mass block 12 moves toward the frame 16 under the action of acceleration. Exemplarily, the following description is made with the acceleration direction as the second direction 64. Fig.10 The mass block 12 is constructed in a square shape, and two flexible beams 14 are arranged on the left and right sides of the mass block 12. The movable contact 101 is arranged on the side wall of the front side of the mass block 12, and the fixed contact 102 is constructed in two. The two fixed contacts 102 are arranged on the inner wall of the frame 16, and the side wall of the mass block where the movable contact 101 is arranged and the inner wall of the frame 16 where the fixed contacts are arranged are located on the same side. When projected along the acceleration direction, the projection of the movable contact 101 partially overlaps with the projections of the two fixed contacts 102, so that when the mass block 12 drives the movable contact 101 to move, the movable contact and the fixed contact are in contact and conductive. Preferably, see Fig.11 , the two fixed contacts 102 are arranged along the first direction 63 , and the movable contact 101 and the fixed contact 102 are both configured in a rectangular shape.

[0059] Fig. 9 The detection capacitor group 40 and the terminal group 50 of the micro inertial switch 100 shown in FIG. Figure 1 The micro inertial switch 100 shown only needs to be Figure 1 Based on the micro-inertial switch 100 shown, the detection capacitor group 40 is adaptively adjusted so that when the mass block 12 moves, the first electrode plate 42 can be driven to move, thereby changing the corresponding facing area between the first electrode plate 42 and the second electrode plate 44. Exemplarily, a detection capacitor group 40 is provided in the micro-inertial switch 100. There is a gap between the two first electrodes 42 of the detection capacitor group 40. Preferably, in order to enhance the sensitivity of the detection capacitor group so that the change in the facing area is consistent with the change in displacement, the gap is greater than or equal to the width of the second electrode plate 44. Here, the width of the second electrode plate 44 refers to the length of the second electrode plate 44 along the second direction. Since the two second electrodes 44 are arranged opposite to one first electrode plate 42, the gap between the two second electrodes 44 can be equal to the gap between the two first electrodes 42.

[0060] In particular, see Fig.12 The first electrode 42 is configured to be a plurality of first sub-electrode plates 42a arranged in parallel and electrically connected along the acceleration direction, and the corresponding second electrode 44 is configured to be a plurality of second sub-electrode plates 44a arranged in parallel and electrically connected along the acceleration direction, and the plurality of first sub-electrode plates 42a and the plurality of second sub-electrode plates 44a form a plurality of sub-capacitors connected in parallel. The plurality of sub-capacitors may be two, three, four, etc., which are not specifically limited here. The detection capacitor group 40 has two capacitors connected in series, and each capacitor is composed of a plurality of sub-capacitors connected in parallel. Specifically, see Fig.12 , the first sub-plate 42a and the second sub-plate 44a are both configured as long strips. Preferably, the widths of the first sub-plate 42a and the second sub-plate 44a are consistent. Exemplarily, the first plate 42 is configured to include two long strip-shaped first sub-plates 42a, that is, one detection capacitor group 40 includes four first sub-plates 42a, and one end of the four first sub-plates 42a is connected as a whole through an end connecting strip; the second plate 44 is configured to include two long strip-shaped second sub-plates 44a, and one end of the two second sub-plates 44a is connected as a whole through an end connecting strip.

[0061] In some embodiments, in the natural state, the facing area of ​​the first sub-plate 42a and the second sub-plate 44a of the sub-capacitor is the maximum facing area of ​​the two, that is, the first sub-plate 42a and the second sub-plate 44a of the sub-capacitor are aligned. When the mass block 12 moves forward or backward (that is, in the direction close to the fixed contact or away from the fixed contact), the facing area of ​​each sub-capacitor becomes smaller. In some embodiments, in the natural state, the facing area of ​​the first sub-plate 42a and the second sub-plate 44a of the sub-capacitor is half of the maximum facing area of ​​the two. When the mass block moves forward (that is, in the direction close to the fixed contact), the facing area of ​​each sub-capacitor becomes larger; when the mass block moves backward (that is, in the direction away from the fixed contact), the facing area of ​​each sub-capacitor becomes smaller. In particular, when the facing area of ​​the first sub-plate 42a and the second sub-plate 44a of the sub-capacitor is half of the maximum facing area of ​​the two, the distance between the mass block 12 and the frame 16 along the acceleration direction is half of the width of the first sub-plate 42a, that is, the movable range of the mass block 12 is the width of the first sub-plate 42a.

[0062] Specifically, the micro inertial switch 100 is provided with a group of terminal blocks 50, the first terminal 52 is connected to any second sub-plate 44a of a second plate 44 or the end lead of the second plate 44, and the second terminal 54 is connected to any second sub-plate 44a of another second plate 44 or the end connecting strip of the second plate 44.

[0063] See also Fig.13A , the mass block 12 can move along the second direction 64, and the first electrode 42 arranged on the mass block 12 can move with the mass block 12, that is, the first electrode 42 is the movable electrode of the detection capacitor group; and the second electrode 44 is arranged on the second structural layer 20, and is fixed together with the second structural layer 20, that is, the second electrode 44 is the fixed electrode of the detection capacitor group. In the natural state, the facing area of ​​the first sub-electrode plate 42a and the second sub-electrode plate 44a of the sub-capacitor is half of the maximum facing area of ​​the two. Two sub-capacitors connected in parallel constitute a capacitor, and two capacitors connected in series constitute a detection capacitor group. The equivalent circuit diagram thereof can be seen in Fig. 13B . The capacitance of the first sub-capacitor is C11, the capacitance of the second sub-capacitor is C12, and the capacitance of the first capacitor formed by the two sub-capacitors in parallel is C1; the capacitance of the third sub-capacitor is C21, the capacitance of the fourth sub-capacitor is C22, and the capacitance of the second capacitor formed by the two sub-capacitors in parallel is C2. The equivalent capacitance of the detection capacitor group is Cout, because 1 / Cout=1 / C1+1 / C2=1 / (C11+C12)+1 / (C21+C22). When C11=C12=C21=C22, Cout=C11.

[0064] When the mass block 12 moves along the second direction 64 under the action of acceleration, the spacing distance between the first sub-plate and the second sub-plate of the sub-capacitor remains unchanged, and the first sub-plate 42a moves synchronously with the mass block in the second direction 64, so that the area facing each other between the first sub-plate and the second sub-plate of the sub-capacitor increases or decreases. Since the capacitance value of the equivalent capacitance of the detection capacitor group is related to the capacitance value of the sub-capacitor, the change of the area facing each other between the first sub-plate and the second sub-plate can be obtained by detecting the capacitance value Cout of the equivalent capacitance of the detection capacitor group, so as to understand the movement of the mass block 12.

[0065] The micro-inertial switch 100 disclosed in the present invention prepares a first electrode plate and a second electrode plate (i.e., prepares metal flat plate electrodes) on the upper side of the mass block of the first structural layer and the lower side of the second structural layer to form a parallel plate capacitor. The out-of-plane displacement change of the mass block can be tested by detecting the change of the gap between the plates of the parallel plate capacitor, or the in-plane displacement change of the mass block can be tested by detecting the change of the area facing the electrodes of the parallel plate capacitor, thereby realizing the characterization of the dynamic characteristics of the micro-inertial switch for in-plane and out-of-plane motion.

[0066] A plurality of groups of parallel plate capacitors are prepared on the upper side of the mass block of the first structural layer and the lower side of the second structural layer of the micro inertial switch 100 to form a rectangular or annular capacitor array. The changes in the array capacitance of different areas of the microstructure (sensitive structure of the micro inertial switch) can also be detected, and the displacement changes of different areas of the microstructure can be tested, so as to obtain the motion posture of the microstructure under normal operation or external excitation.

[0067] And the capacitance signal of the detection capacitor is only led out through one or more groups of terminal blocks arranged on the second structure layer, that is, the first electrode plate on the mass block does not need additional leads, which simplifies the manufacturing process. In addition, since the first electrode plate arranged on the mass block is not directly energized, the mass block can be undisturbed during the dynamic characteristic test, so the motion characteristics of the sensitive structure mass block can be tested during the normal operation of the micro inertial switch.

[0068] The above are only several embodiments of the present invention. Those skilled in the art may make various changes or modifications to the embodiments of the present invention based on the contents disclosed in the application documents without departing from the spirit and scope of the present invention.

Claims

1. A micro inertial switch with online detection function, characterized in that: The invention comprises a first structural layer, a second structural layer, a fixed contact, a movable contact, at least one group of detection capacitors and a terminal group adapted to the number of detection capacitors. A mass block which is suspended by a flexible beam and can move along the acceleration direction is formed in the first structural layer, and the movable contact is arranged on the mass block. Under the action of acceleration, the mass block can drive the movable contact to move along the acceleration direction so that the movable contact is in contact with the fixed contact and is turned on. Each group of the detection capacitor group includes two pairs of first and second electrode plates arranged opposite to each other, and the first structure layer and the second structure layer are stacked; one side of the first structure layer close to the second structure layer is provided with two first electrode plates of the detection capacitor group that are electrically connected to each other, and the two first electrode plates are electrically isolated from the movable contact; one side of the second structure layer close to the first structure layer is provided with two second electrode plates of the detection capacitor group that are independent of each other, and the two second electrode plates are respectively coupled to a first terminal and a second terminal of a terminal group arranged on the second structure layer, and each group of the detection capacitor group is electrically connected to the outside only through the first terminal and the second terminal; The mass block can move in the acceleration direction under the action of acceleration to change the spacing distance or the facing area between the corresponding first electrode plate and the second electrode plate, thereby changing the capacitance of the detection capacitor group; when acceleration acts, the real-time capacitance of the detection capacitor group can be measured online, and the dynamic characteristics of the micro inertial switch can be obtained by detecting the capacitance change of the capacitor group.

2. The micro inertial switch according to claim 1, characterized in that: The micro inertial switch further comprises a third structural layer, the third structural layer is arranged on a side of the first structural layer away from the second structural layer, the fixed contact is configured as two, and the two fixed contacts are arranged on a side of the third structural layer close to the first structural layer; The acceleration direction is the height direction, and the mass block can move in the height direction under the action of the acceleration to change the spacing distance between the corresponding first electrode plate and the second electrode plate.

3. The micro inertial switch according to claim 2, characterized in that: The two first electrode plates of each detection capacitor group are constructed as a whole, and the two second electrode plates are located in the same plane and can be completely projected onto the first electrode plate.

4. The micro inertial switch according to claim 3, characterized in that: The mass block is configured in a circular shape, the micro inertial switch comprises four detection capacitor groups and four terminal groups, the four detection capacitor groups are arranged circumferentially on the mass block, and the two second plates of each detection capacitor group are respectively coupled to a first terminal and a second terminal of a terminal group; The two first plates of each detection capacitor group are integrally formed into a sector of 1 / 4 circle, and the second plates of each detection capacitor group are integrally formed into a sector of 1 / 8 circle.

5. The micro inertial switch according to claim 3, characterized in that: The mass block is configured in a rectangular shape, the micro inertial switch comprises four detection capacitor groups and four terminal groups, the four detection capacitor groups are distributed at four corners of the mass block to form two rows and two columns, and the two second electrodes of each detection capacitor group are respectively coupled to a first terminal and a second terminal of a terminal group; The second pole plates of the four detection capacitor groups are arranged in four rows and two columns, and the four connection terminals are arranged in two columns.

6. The micro inertial switch according to any one of claims 2 to 5, characterized in that: One side of the third structure layer protrudes from the second structure layer. Two leads are provided on one side of the third structure layer close to the first structure layer. The two leads are electrically connected to a fixed contact respectively and extend to the protruding part of the third structure layer.

7. The micro inertial switch according to claim 1, characterized in that: The mass block moves in a plane under the action of acceleration, the first structural layer is configured to include a frame, the mass block and the flexible beam are arranged in an internal cavity formed by the frame, the movable contact is arranged on a side wall of the mass block, the fixed contact is configured to be two, and the two fixed contacts are arranged on the inner side wall of the frame, wherein the side wall of the mass block where the movable contact is arranged and the inner side wall of the frame where the fixed contact is arranged are located on the same side of the mass block; Under the action of acceleration, the first electrode plate moves with the mass block to change the corresponding facing area between the first electrode plate and the second electrode plate.

8. The micro inertial switch according to claim 7, characterized in that: The first electrode plate is constructed into a plurality of first sub-electrode plates arranged in parallel and electrically connected along the acceleration direction, and the corresponding second electrode plate is constructed into a plurality of second sub-electrode plates arranged in parallel and electrically connected along the acceleration direction, and the plurality of first sub-electrode plates and the plurality of second sub-electrode plates form a plurality of sub-capacitors in parallel.

9. The micro inertial switch according to claim 8, characterized in that: The first sub-plate and the second sub-plate are both configured as long strips, and in a natural state, the facing area of ​​the first sub-plate and the second sub-plate is half of the maximum facing area of ​​the two.

10. The micro inertial switch according to any one of claims 7 to 9, characterized in that: The micro inertial switch also includes a third structural layer, which is arranged on a side of the first structural layer away from the second structural layer, and one side of the third structural layer protrudes from the second structural layer. One side of the third structural layer is located on the same side as the side wall of the mass block where the movable contact is set, and two leads are provided on a side of the third structural layer close to the first structural layer, and the two leads are respectively electrically connected to a fixed contact, and the two leads extend to the protruding part of the third structural layer.

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