MEMS accelerometer and application thereof

Abstract

The invention discloses an MEMS (Micro Electro Mechanical System) accelerometer and an application thereof. The MEMS accelerometer comprises a substrate; the units are arranged on the substrate; the unit comprises a mass block which is spaced from the plane where the substrate is located and is configured to be capable of moving in the first direction parallel to the substrate under the action of a first acceleration; the lever structure is connected to the base plate and is located on the plane parallel to the base plate, and the lever structure is connected with the mass block; the fixed electrode fingers are connected with the substrate and arranged on the first side of the mass block in the second direction, and the fixed electrode fingers extend in the second direction; the movable electrodes are arranged on the first side, in the second direction, of the mass block and connected with the lever structure, and each movable electrode comprises a plurality of movable electrode fingers. According to the invention, only two times of single-side etching are needed; a lever structure is introduced, so that the measurement sensitivity can be greatly improved, and the measuring range of the accelerometer is not influenced; and multi-axis monolithic integration is easy to carry out.

Description

Technical Field

[0001] The present invention relates to the technical field of acceleration measurement, and in particular to a MEMS accelerometer and applications thereof. Background Art

[0002] Micro-electromechanical system (MEMS) accelerometers are mainly used in application scenarios that need to withstand extreme acceleration environments, such as collision and impact tests. At present, the form of MEMS accelerometers is a piezoresistive accelerometer structure, and its measurement principle is the piezoresistive effect. When there is an external acceleration input, the movable mass moves in the opposite direction of the acceleration, and the cantilever beam deforms, resulting in changes in the stress on the cantilever beam. The piezoresistors sense the stress changes on the cantilever beam, and their resistance values ​​also change.

[0003] In order to improve the measurement sensitivity of MEMS piezoresistive accelerometers, it is necessary to reduce the thickness of the cantilever beam and increase the thickness of the movable mass block, which requires a double-sided processing process, and the reverse side needs to be etched twice, which poses a high difficulty to the MEMS processing technology and seriously affects the yield rate. In addition, the piezoresistive accelerometer structure is difficult to achieve multi-axis monolithic integration. If acceleration measurement in three dimensions of space is to be performed, at least three accelerometers are required for assembly, which will result in a large area and high raw material costs. Summary of the invention

[0004] The invention provides a MEMS accelerometer and application thereof.

[0005] In a first aspect, the present invention provides a micro-electromechanical system (MEMS) accelerometer, comprising:

[0006] substrate;

[0007] A plurality of units disposed on the substrate;

[0008] The unit comprises:

[0009] A mass block, the mass block is spaced from the plane where the substrate is located, and is configured to be displaceable along a first direction parallel to the substrate under the action of a first acceleration;

[0010] A lever structure, the lever structure is connected to the base plate, and the lever structure is connected to the mass block in a plane parallel to the base plate;

[0011] a plurality of fixed electrode fingers, the fixed electrode fingers being connected to the substrate and being arranged on a first side of the mass block in a second direction, the fixed electrode fingers extending along the second direction, wherein the second direction is parallel to the substrate and orthogonal to the first direction;

[0012] A movable electrode, the movable electrode is arranged on a first side of the mass block in the second direction and connected to the lever structure, each of the movable electrodes includes a plurality of movable electrode fingers;

[0013] The lever structure is configured to drive each movable electrode finger to undergo a second displacement along the first direction between every two fixed electrode fingers along with the first displacement of the mass block in the first direction, wherein an absolute value of the second displacement is greater than an absolute value of the first displacement.

[0014] In a second aspect, the present invention provides a micro-electromechanical system (MEMS) accelerometer, comprising:

[0015] substrate;

[0016] A plurality of units disposed on the substrate;

[0017] The unit comprises:

[0018] A mass block, the mass block is spaced from the plane where the substrate is located, and is configured to be displaceable along a first direction parallel to the substrate under the action of a first acceleration;

[0019] a lever structure, the lever structure being connected to the substrate, the lever structure being disposed on a first side of the mass block along a second direction, the second direction being parallel to the substrate and being orthogonal to the first direction, one end of the lever structure being connected to the mass block at a side of the mass block close to the first side, and the other end of the lever structure extending away from the mass block along the second direction;

[0020] a plurality of fixed electrode fingers, the fixed electrode fingers being connected to the substrate and being arranged on a first side of the mass block in the second direction;

[0021] A movable electrode, the movable electrode is arranged on a first side of the mass block in the second direction, each of the movable electrodes comprises a plurality of movable electrode fingers, and the movable electrode fingers are connected to the other end of the lever structure away from the mass block;

[0022] The unit is configured to obtain the acceleration of the mass block moving along the first direction based on the capacitance change caused by the displacement of each movable electrode finger along the first direction between two fixed electrode fingers, wherein the displacement along the first direction is driven by the movement of the lever structure, and the movement of the lever structure is driven by the displacement of the mass block along the first direction.

[0023] In a third aspect, the present invention provides a MEMS accelerometer device, comprising:

[0024] A MEMS accelerometer as described in the first aspect; and a circuit element.

[0025] In a fourth aspect, the present invention provides a MEMS accelerometer device, comprising:

[0026] A MEMS accelerometer as described in the second aspect; and a circuit element.

[0027] In a fifth aspect, the present invention provides an electronic device, comprising:

[0028] The MEMS accelerometer according to the first aspect;

[0029] a control circuit; and a correction circuit.

[0030] In a sixth aspect, the present invention provides an electronic device, comprising:

[0031] The MEMS accelerometer according to the second aspect;

[0032] a control circuit; and a correction circuit.

[0033] In a seventh aspect, the present invention provides a portable electronic device, comprising:

[0034] The MEMS accelerometer according to the first aspect;

[0035] A housing for accommodating the MEMS accelerometer;

[0036] A processing module, housed in the housing, for processing output data from the MEMS accelerometer;

[0037] A display module is housed in the housing; and

[0038] The light-transmitting cover covers the opening module of the housing.

[0039] In an eighth aspect, the present invention provides a portable electronic device, comprising:

[0040] The MEMS accelerometer according to the second aspect;

[0041] A housing for accommodating the MEMS accelerometer;

[0042] A processing module, housed in the housing, for processing output data from the MEMS accelerometer;

[0043] A display module is housed in the housing; and

[0044] The light-transmitting cover covers the opening module of the housing.

[0045] In a ninth aspect, the present invention provides a mobile body, comprising:

[0046] A MEMS accelerometer as described in the first aspect; and a posture control module.

[0047] In a tenth aspect, the present invention provides a mobile object, comprising:

[0048] The MEMS accelerometer as described in the second aspect; and a posture control module. BRIEF DESCRIPTION OF THE DRAWINGS

[0049] Figure 1 It is a structural schematic diagram of a MEMS accelerometer of the present invention;

[0050] Figure 2 It is a schematic diagram of the MEMS structure change caused by external acceleration input in the present invention;

[0051] Figure 3 It is a schematic diagram of the lever structure of the present invention;

[0052] Figure 4 It is a schematic diagram of the working principle of the lever structure of the present invention;

[0053] Figure 5 It is a schematic diagram of the comb capacitance detection principle of the present invention;

[0054] Figure 6 is another structural schematic diagram of a MEMS accelerometer of the present invention;

[0055] Figure 7 is another structural schematic diagram of a MEMS accelerometer of the present invention;

[0056] Figure 8 It is a schematic diagram of the secondary lever structure of the present invention;

[0057] Fig. 9 is another structural schematic diagram of a MEMS accelerometer of the present invention;

[0058] Fig.10 is another structural schematic diagram of a MEMS accelerometer of the present invention;

[0059] Fig.11 It is a schematic diagram of the Z-direction acceleration detection principle of the present invention;

[0060] Fig.12 is another structural schematic diagram of a MEMS accelerometer of the present invention;

[0061] Fig.13 is a cross-sectional view of a MEMS accelerometer device of the present invention;

[0062] Fig.14 is a three-dimensional diagram of an electronic device of the present invention;

[0063] Fig.15is a top view of a portable electronic device of the present invention;

[0064] Fig.16 is a functional block diagram of a general structure of a portable electronic device of the present invention;

[0065] Fig.17 It is a structural schematic diagram of a mobile body of the present invention;

[0066] exist Fig.13 1. MEMS accelerometer; 10. cover; 100. MEMS accelerometer device; 110. circuit element; 120. package; 130. base; 131. recess; 131a. first recess; 131b. second recess; 133. internal terminal; 134. external terminal; 140. cover; BW1, BW2, welding wire; S1. accommodation space; T, terminal;

[0067] exist Fig.14 In the figure, 1100, personal computer; 1102, keyboard; 1104, main body; 1106, display unit; 1108, display unit; 1110, control circuit; 1120, correction circuit;

[0068] exist Fig.17 In the figure, 1500 is a car; 1501 is a car body; 1502 is a car body posture control device; 1503 is a wheel. DETAILED DESCRIPTION

[0069] The specific implementation of the present invention is further described in detail below in conjunction with the accompanying drawings. The following content is used to illustrate the present invention, but is not used to limit the scope of the present invention.

[0070] In the description of the present invention, it should be understood that the terms "first" and "second" etc. are used in the present invention to distinguish different objects rather than to describe a specific order.

[0071] like Figure 1 As shown, the present invention provides a micro-electromechanical system (MEMS) accelerometer. Figure 1 (a) is the top view of the MEMS accelerometer. Figure 1 (b) is a cross-sectional view of the MEMS accelerometer. Figure 1 (b) It can be seen that the cross section of the MEMS accelerometer has only two heights, where h 0 Indicates the total thickness of the device, h 1 It represents the thickness of the mass block, and the base is the substrate. Only two etchings are required on a single side to obtain the structure, which greatly reduces the process difficulty and improves the yield rate.

[0072] MEMS accelerometers include:

[0073] substrate;

[0074] A plurality of units disposed on a substrate;

[0075] The unit comprises:

[0076] The mass block is spaced apart from the plane where the substrate is located, and is configured to be displaceable in a first direction parallel to the substrate under the action of a first acceleration. The first direction can be understood as the Y-axis direction. Based on the force balance principle, when there is a first acceleration input, the mass block moves in the opposite direction of the first acceleration until the spring restoring force of the connecting member is balanced with the inertial force. At this time, the mass block moves downward by a displacement of Δy, which can be seen in Figure 2 It is understandable that the movable mass block is the mass block. In some embodiments, the displacement Δy is calculated using the following formula:

[0077]

[0078] Where m represents the mass of the mass block, a represents the first acceleration, and k m Indicates the stiffness of the connector.

[0079] The lever structure is connected to the substrate and connected to the mass block in a plane parallel to the substrate. There are two lever structures, and the two lever structures are respectively connected to a first side portion and a second side portion of the mass block that are opposite in a first direction.

[0080] A plurality of fixed electrode fingers are connected to the substrate and are arranged on the first side of the mass block in the second direction, and the fixed electrode fingers extend along the second direction. Every two fixed electrode fingers are connected to the substrate through a support seat. The second direction is parallel to the substrate and orthogonal to the first direction. It should be noted that the support seat is Figure 1 In (a), the second direction of the fixed electrode 1 and the fixed electrode 2 can be understood as the X-axis direction, and "orthogonal" means that in addition to the case of crossing at 90°, it also includes the case of crossing at an angle slightly inclined from 90° (for example, 90°±5°). Specifically, the case where the X-axis is inclined at about ±5° relative to the normal direction of the YZ plane, the case where the Y-axis is inclined at about ±5° relative to the normal direction of the XZ plane, and the case where the Z-axis is inclined at about ±5° relative to the normal direction of the XY plane are also included in "orthogonal".

[0081] A movable electrode is arranged on a first side of the mass in the second direction and connected to the lever structure. Each movable electrode includes a plurality of movable electrode fingers, and the movable electrode includes a connecting rod and a movable electrode finger, the connecting rod is connected to the lever structure and extends from the lever structure along the first direction, the movable electrode finger is arranged on one side of the connecting rod along the first direction, and the movable electrode finger extends along the second direction.

[0082] The lever structure is configured to drive each movable electrode finger to undergo a second displacement along the first direction between each two fixed electrode fingers as the mass block undergoes a first displacement in the first direction. The absolute value of the second displacement is greater than the absolute value of the first displacement. The lever structure is connected to the mass block at the first side and the second side of the mass block near the first side, and extends toward the first side along the second direction. A movable electrode finger is disposed on each connecting rod.

[0083] like Figure 3 As shown, in some embodiments, the lever structure is a suspension structure and a primary lever structure. Figure 3 (a) is a top view of the lever structure. Figure 3 (b) is a cross-sectional view of the lever structure. The primary lever structure includes a lever and a fulcrum, wherein the fulcrum is connected to a substrate. In a first direction, the lever is connected to the fulcrum. In a second direction, the first end of the lever is connected to the mass block. The second end of the lever is away from the mass block along the second direction and connected to the movable electrode. The distance between the fulcrum and the first end is smaller than the distance between the fulcrum and the second end. It can be understood that the first end of the lever is the input end, and the second end of the lever is the output end. The first end of the lever is connected to the mass block via a connector that can be extended and retracted along the first direction, such as Figure 1 As shown in Fig. 2, the connecting member is a cantilever beam. The lever is connected to the fulcrum via a bridge extending along the first direction.

[0084] Figure 4 The working principle of the lever structure is shown. When there is no acceleration input, the lever does not change, such as Figure 4 (a). When there is acceleration input, the mass block moves downward by Δy, that is, the input end of the lever moves downward by Δy, and the lever structure changes as follows Figure 4 The movement of (b) causes the output end of the lever to have an upward displacement Δy′. Furthermore, from the principle of lever, we can know that there is the following expression:

[0085]

[0086] Among them, l 0 Indicates the input force arm length, l 1 The lever structure is introduced to amplify the displacement of the mass block by α times, which improves the sensitivity of capacitance detection, and the amplification factor can be adjusted by adjusting the input force arm length and the output force arm length.

[0087] The amplified displacement is converted into capacitance for detection using the comb capacitance detection principle. Figure 5 The working principle of capacitance detection is shown. Figure 5(a) is a comb-tooth capacitor, where the movable comb teeth and the fixed comb teeth form a flat plate capacitor. The movable comb teeth are connected to the output end of the lever and move with the movement of the mass block. The fixed comb teeth and the fixed electrode are immovable. It can be understood that the movable comb teeth are the movable electrode fingers, and the fixed comb teeth are the fixed electrode fingers. When there is no movement, the capacitance of the comb-tooth capacitor is C 0 , using the following expression:

[0088]

[0089] Where n represents the logarithm of the plate capacitor, ε represents the dielectric constant of the capacitor dielectric, and S represents the overlapping area of ​​the plate capacitor. It should be noted that Figure 5 Only one pair of capacitors is shown, but in practice multiple pairs of capacitors may be included.

[0090] When the movable comb teeth are displaced Δy′ in the vertical upward direction, the gap of the capacitor changes, such as Figure 5 (b) is shown. At this time, the capacitance of the comb capacitor is C 1 , using the following expression:

[0091]

[0092] The capacitance change ΔC caused by the movement of the movable comb teeth 1 , using the following expression:

[0093]

[0094] Substituting equation (1) and equation (2) into equation (5), we can obtain:

[0095]

[0096] in, Represents a coefficient related to the structure size.

[0097] Figure 5 Shows Figure 1 In some embodiments, the structural flat plate capacitor formed by the upper movable comb teeth and the fixed comb teeth is the upper flat plate capacitor. Similarly, the structural flat plate capacitor formed by the lower movable comb teeth and the fixed comb teeth is the lower flat plate capacitor. The following formula is used to calculate the change in the lower flat plate capacitor ΔC 2 :

[0098]

[0099] After differentiating the upper and lower comb capacitors, the sum of the capacitance changes caused by acceleration, ΔC, is:

[0100] ΔC=ΔC 1 -ΔC2 =2βa (8)

[0101] It can be seen from equations (6), (7) and (8) that the input acceleration a is ultimately converted into a measurable capacitance signal for detection.

[0102] The remaining embodiments of the MEMS accelerometer of the present invention are described below:

[0103] Figure 6 The schematic diagrams of the structures of other embodiments of a MEMS accelerometer of the present invention are shown, wherein the fulcrum of the lower half of the lever structure is changed, that is, from the lower end of the lever to the upper end of the lever, but the function does not change. It should be noted that Figure 6 Only the change of one fulcrum is given, and the change of the positions of both fulcrums is also included in the present invention, which will not be described in detail here.

[0104] Figure 7 The schematic diagram of the structure of some other embodiments of a MEMS accelerometer of the present invention is shown, wherein the lever structure is a two-stage lever structure. In the two-stage lever structure, each stage of the lever structure includes a lever and a fulcrum connected to each other, and the fulcrum of each stage of the lever structure is connected to the substrate. The lever in each stage of the lever structure has a first end close to the mass block along the second direction and a second end away from the mass block, and the distance between the fulcrum and the first end is less than the distance between the fulcrum and the second end. Compared with Figure 1 The primary lever structure in the sensor can further amplify the displacement and increase the sensitivity.

[0105] In some embodiments, the secondary lever structure is as follows Figure 8 As shown. The first end of the lever in the first-level lever structure is connected to the mass block, the second end of the lever in the first-level lever structure is connected to the first end of the lever in the second-level lever structure, and the second end of the lever in the second-level lever structure is connected to the movable electrode. Among them, the first end of the lever in the first-level lever structure is the first-level lever input end, the second end of the lever in the first-level lever structure is the first-level lever output end, the first end of the lever in the second-level lever structure is the second-level lever input end, and the second end of the lever in the second-level lever structure is the second-level lever output end.

[0106] It should be noted that the present invention not only includes Figure 1 The primary lever structure shown and Figure 7The secondary lever structure shown also includes a multi-stage lever structure. The lever structure is a multi-stage lever structure, in which each stage of the lever structure includes a lever and a fulcrum connected to each other, and the fulcrum of each stage of the lever structure is connected to the substrate. The lever in each stage of the lever structure has a first end close to the mass block along the second direction and a second end away from the mass block, and the distance between the fulcrum and the first end is less than the distance between the fulcrum and the second end. The first end of the lever in the first stage of the lever structure is connected to the mass block, the first end of the lever in the last stage of the lever structure is connected to the second end of the lever in the second stage of the lever structure, and the second end of the last stage of the lever structure is connected to the movable electrode. In the multi-stage lever structure between the first stage of the lever structure and the last stage of the lever structure, the first end of the lever in the next stage of the lever structure is connected to the second end of the lever in the previous stage of the lever structure.

[0107] Regardless of whether it is a two-stage lever structure or a multi-stage lever structure, the first end of the lever in the first-stage lever structure of both is connected to the mass block through a connecting member that can be telescopic along a first direction.

[0108] Fig. 9 The structural schematic diagrams of other embodiments of a MEMS accelerometer of the present invention are shown. The movable electrode includes a connecting rod and a movable electrode finger, the connecting rod is connected to the lever structure and extends from the lever structure along a first direction, the movable electrode finger is arranged on both sides of the connecting rod along the first direction, and the movable electrode finger extends along a second direction. Furthermore, there are two lever structures, and the two movable electrode fingers are arranged on both sides of the connecting rod along the first direction.

[0109] The movable electrode fingers are arranged on both sides of the connecting rod along the first direction, that is, a bilateral fixed comb arrangement structure. This structure can effectively eliminate the error caused by the acceleration input in the non-sensitive direction, the output signals of the fixed electrode 1 and the fixed electrode 2 are in phase, the output signals of the fixed electrode 3 and the fixed electrode 4 are in phase, but the phase of the fixed electrode 1 and the fixed electrode 2 is opposite to the phase of the fixed electrode 3 and the fixed electrode 4.

[0110] Fig.10 The schematic diagrams of the structures of other embodiments of a MEMS accelerometer of the present invention are shown, namely, a dual-axis monolithic integrated MEMS accelerometer structure. Fig.10 (a) is the top view of the MEMS accelerometer. Fig.10 (b) is a cross-sectional view of the MEMS accelerometer.

[0111] The unit further includes: a fixed electrode, which is disposed on the substrate and within the projection range of the mass block on the substrate, and the mass block is configured to be displaceable along a third direction perpendicular to the substrate under the action of the second acceleration, wherein the third direction can be understood as the Z-axis direction.

[0112] It is only necessary to add an electrode (Z-direction electrode, i.e. fixed electrode) under the mass block to detect the Z-direction movement of the mass block. Fig.11 shown. Fig.11 (a) is the cross-sectional view of the Z-direction detection structure when there is no acceleration input. Fig.11 (b) is a cross-sectional view of the Z-direction detection structure when there is an upward acceleration input perpendicular to the structural plane. When there is an upward acceleration input perpendicular to the structural plane, the mass block moves along the Z direction, causing the gap between the mass block and the Z-direction electrode to change, and then the plate capacitance between the mass block and the Z-direction electrode to change. By measuring the change in capacitance, the acceleration information of the Z-direction input can be obtained.

[0113] Fig.12 The schematic diagram of the structure of another embodiment of a MEMS accelerometer of the present invention is shown. Fig.10 By rotating one of the structures 90°, acceleration measurements in three directions can be performed. Fig.10 The MEMS accelerometer shown is integrated and packaged as the smallest structural unit for three-axis acceleration measurement, which can not only reduce the volume and save packaging costs, but also ensure process consistency and improve manufacturing yield due to its similar structure. Fig.12 (a) is the top view of the MEMS accelerometer. Fig.12 (b) is a cross-sectional view of the MEMS accelerometer.

[0114] The MEMS accelerometer of the present invention only needs to be etched twice on a single side, which simplifies the process, improves the yield of finished products, and saves money and time costs. The introduced lever structure greatly improves the measurement sensitivity without affecting the range of the accelerometer, which is beneficial to improving the dynamic range of the accelerometer. It is easy to perform multi-axis monolithic integration, which brings space and cost advantages for spatial acceleration motion measurement.

[0115] Reference Figure 1 The present invention provides some embodiments of a micro-electromechanical system (MEMS) accelerometer, comprising:

[0116] substrate;

[0117] A plurality of units disposed on a substrate;

[0118] The unit comprises:

[0119] The mass block is spaced from the plane where the substrate is located and is configured to be displaceable along a first direction parallel to the substrate under the action of a first acceleration.

[0120] A lever structure, the lever structure is connected to the substrate, the lever structure is arranged on the first side of the mass block along the second direction, the second direction is parallel to the substrate and is orthogonal to the first direction, one end of the lever structure is connected to the mass block on the side of the mass block close to the first side, the other end of the lever structure extends away from the mass block along the second direction, and the lever structure is connected to the mass block through a connecting member that can be extended and retracted along the first direction. There are two lever structures, and the two lever structures are respectively connected to the first side and the second side of the mass block that are opposite to each other in the first direction.

[0121] A plurality of fixed electrode fingers are connected to the substrate and are arranged on a first side of the mass block in the second direction. Every two fixed electrode fingers are connected to the substrate through a support seat, and the fixed electrode fingers extend along the second direction.

[0122] A movable electrode, the movable electrode is arranged on a first side of the mass block in the second direction, each movable electrode includes a plurality of movable electrode fingers, and the movable electrode fingers are connected to the other end of the lever structure away from the mass block. Further, the movable electrode is connected to the other end of the lever structure away from the mass block, the movable electrode includes a connecting rod and a movable electrode finger, the connecting rod is connected to the lever structure and extends from the lever structure in the first direction, and the movable electrode finger is connected to the connecting rod and extends in the second direction.

[0123] The unit is configured to obtain the acceleration of the mass block moving along the first direction based on the capacitance change caused by the displacement of each movable electrode finger between two fixed electrode fingers along the first direction, wherein the displacement along the first direction is driven by the movement of the lever structure, and the movement of the lever structure is driven by the displacement of the mass block along the first direction.

[0124] In some embodiments, the lever structure is a multi-stage lever structure, in which each stage of the lever structure includes a lever and a fulcrum connected to each other, and the fulcrum of each stage of the lever structure is connected to the substrate. The lever in each stage of the lever structure has a first end close to the mass block along the second direction and a second end away from the mass block, and the distance between the fulcrum and the first end is less than the distance between the fulcrum and the second end.

[0125] like Fig.13 As shown, the present invention provides some embodiments of MEMS accelerometer devices, including:

[0126] A MEMS accelerometer as described above; and a circuit element.

[0127] Fig.13 are cross-sectional views illustrating MEMS accelerometer devices according to some embodiments of the present invention.

[0128] like Fig.13As shown, the MEMS accelerometer device 100 includes a MEMS accelerometer 1, a circuit element 110, and a package 120 that accommodates the MEMS accelerometer 1 and the circuit element 110. The MEMS accelerometer 1 is not particularly limited, and for example, the above-mentioned structure can be used. Such a MEMS accelerometer device 100 can be suitably used as an inertial measurement unit (IMU: Inertial Measurement Unit).

[0129] The circuit element 110 (IC) is bonded to the cover 10 of the MEMS accelerometer 1 via a bonding component. In addition, the circuit element 110 is electrically connected to each terminal T of the MEMS accelerometer 1 via a bonding wire BW1, and is electrically connected to the package 120 (internal terminal 133 described later) via a bonding wire BW2. The circuit element 110 includes a drive circuit for driving the MEMS accelerometer 1, a detection circuit for detecting acceleration based on an output signal from the MEMS accelerometer 1, a correction circuit for correcting the detected acceleration, an output circuit for converting a signal from the detection circuit into a prescribed signal and outputting the signal, etc. In addition, the circuit element 110 can be provided on the outside of the package 120, or can be omitted.

[0130] The package 120 includes a base 130 and a cover 140 bonded to the upper surface of the base 130 so as to form a housing space S1 for housing the MEMS accelerometer 1 and the circuit element 110 between the base 130 and the cover 140 .

[0131] The base 130 has a cavity shape having a recess 131 opened to the upper surface. The recess 131 has a first recess 131a opened to the upper surface of the base 130 and a second recess 131b opened to the bottom surface of the first recess 131a.

[0132] On the other hand, the cover 140 is plate-shaped and bonded to the upper surface of the base 130 so as to cover the opening of the recess 131. Thus, the cover 140 covers the opening of the recess 131 to form a housing space S1 in which the MEMS accelerometer 1 and the circuit element 110 are housed.

[0133] The storage space S1 is hermetically sealed and has the same atmosphere as the storage space S of the MEMS accelerometer 1. Therefore, even if the airtightness of the storage space S is destroyed and the storage space S is connected to the storage space S1, the atmosphere of the storage space S can be maintained as it is. Therefore, the change in the physical quantity detection characteristics of the MEMS accelerometer 1 caused by the change in the atmosphere of the storage space S can be suppressed, and the MEMS accelerometer device 100 can be driven stably. In addition, the "same atmosphere" is not limited to the case of complete consistency, and includes the case where there are inevitable manufacturing errors such as slightly different pressures in the two spaces. In addition, the atmosphere of the storage space S1 may also be different from that of the storage space S.

[0134] The constituent material of the susceptor 130 is not particularly limited, and for example, various ceramics such as oxide ceramics such as alumina, silicon dioxide, titanium dioxide, and zirconium oxide, and nitride ceramics such as silicon nitride, aluminum nitride, and titanium nitride can be used. In this case, the susceptor 130 can be manufactured by sintering a stack of ceramic sheets (green sheets). By setting such a structure, the recess 131 can be easily formed.

[0135] The material of the lid 140 is not particularly limited, but may be a member having a linear expansion coefficient similar to that of the material of the base 130. For example, when the base 130 is made of ceramic as described above, an alloy such as Kovar is preferably used.

[0136] In addition, the base 130 has a plurality of internal terminals 133 arranged on the bottom surface of the first recess 131a and a plurality of external terminals 134 arranged on the lower surface. Then, each internal terminal 133 is electrically connected to a predetermined external terminal 134 via an internal wiring (not shown) arranged in the base 130. In addition, the plurality of internal terminals 133 are electrically connected to the circuit element 110 via bonding wires BW2, respectively. Thus, electrical connection with the circuit element 110 can be made from the outside of the package 120, and the mounting of the MEMS accelerometer device 100 becomes easy.

[0137] The MEMS accelerometer device 100 has been described above. Such a MEMS accelerometer device 100 includes the MEMS accelerometer 1 and the circuit element 110 as described above. Therefore, the effects of the MEMS accelerometer 1 described above can be enjoyed, and the MEMS accelerometer device 100 has high reliability.

[0138] In addition, the structure of the MEMS accelerometer device 100 is not particularly limited, and for example, the MEMS accelerometer 1 and the circuit element 110 may be arranged in the opposite manner. That is, the circuit element 110 may be arranged on the bottom surface of the recess 131, and the MEMS accelerometer 1 may be arranged on the upper surface of the circuit element 110. In addition, the package 120 may be eliminated and the circuit element 110 and the MEMS accelerometer 1 may be molded using a molding material.

[0139] like Fig.14 As shown, the present invention provides an electronic device, comprising:

[0140] A MEMS accelerometer as described above;

[0141] a control circuit; and a correction circuit.

[0142] Fig.14 is a perspective view showing electronic devices according to some embodiments of the present invention.

[0143] Fig.14 The electronic device of the present invention is applicable to a mobile (or notebook) personal computer 1100 shown in the figure. In the figure, the personal computer 1100 is composed of a main body 1104 with a keyboard 1102 and a display unit 1106 with a display unit 1108, and the display unit 1106 is supported rotatably relative to the main body 1104 via a hinge structure.

[0144] Such a personal computer 1100 includes a MEMS accelerometer 1, a control circuit 1110 for controlling the driving of the MEMS accelerometer 1, and a correction circuit 1120 for correcting a physical quantity detected by the MEMS accelerometer 1 based on, for example, the ambient temperature. The MEMS accelerometer 1 is not particularly limited, and, for example, any of the above-described embodiments may be used.

[0145] Such a personal computer 1100 (electronic device) includes the MEMS accelerometer 1, the control circuit 1110, and the correction circuit 1120. Therefore, the above-mentioned effects of the MEMS accelerometer 1 can be enjoyed, and high reliability can be exhibited.

[0146] In addition, the electronic device of the present invention can be applied to, in addition to the personal computer of the above-mentioned embodiment, for example, portable telephones, digital still cameras, smart phones, tablet terminals, clocks (including smart watches), inkjet ejection devices (such as inkjet printers), laptop personal computers, televisions, HMD (head-mounted displays) and other wearable terminals, cameras, video recorders, car navigation devices, pagers, electronic notepads (also including those with communication functions), electronic dictionaries, electronic calculators, electronic game consoles, word processors, workstations, videophones, anti-theft video monitors, electronic binoculars, POS terminals, medical equipment (such as electronic thermometers, blood pressure meters, blood glucose meters, electrocardiogram measuring devices, ultrasonic diagnostic devices, electronic endoscopes), fish finders, various measuring equipment, equipment for mobile terminal base stations, measuring instruments (such as measuring instruments for vehicles, aircraft, and ships), flight simulators, network servers, etc.

[0147] like Fig.15 As shown, the present invention provides some embodiments of portable electronic devices, including:

[0148] A MEMS accelerometer as described above;

[0149] A housing for housing the MEMS accelerometer;

[0150] A processing module is housed in the housing and processes output data from the MEMS accelerometer;

[0151] A display module is housed in the housing; and

[0152] The light-transmitting cover covers the opening module of the shell.

[0153] Fig.15 is a top view of a portable electronic device showing some embodiments of the present invention.

[0154] Fig.16 It is shown Fig.15 A functional block diagram of the schematic structure of a portable electronic device is shown.

[0155] Fig.15 The watch-type activity meter 1400 (activity tracking device, Activity Tracker) shown is a wrist device of the portable electronic device applicable to the present invention. The activity meter 1400 is mounted on the user's arm or other parts (detected body) through a belt 1401. In addition, the activity meter 1400 has a display unit 1402 for digital display and can perform wireless communication. The above-mentioned MEMS accelerometer 1 according to the present invention is installed in the activity meter 1400 as a sensor for measuring acceleration.

[0156] The activity meter 1400 includes a housing 1403 that accommodates the MEMS accelerometer 1, a processing module 1410 that is accommodated in the housing 1403 and processes output data from the MEMS accelerometer 1, a display module 1402 that is accommodated in the housing 1403, and a light-transmitting cover 1404 that covers the opening module of the housing 1403. In addition, a bezel 1405 is provided on the outside of the light-transmitting cover 1404. In addition, a plurality of operation buttons 1406 and 1407 are provided on the side surface of the housing 1403.

[0157] like Fig.16 As shown, the acceleration sensor 1408 as the MEMS accelerometer 1 detects the acceleration of each of the three axes that intersect each other (ideally orthogonal), and outputs a signal (acceleration signal) corresponding to the magnitude and direction of the detected three-axis acceleration. In addition, the angular velocity sensor 1409 detects the angular velocity of each of the three axes that intersect each other (ideally orthogonal), and outputs a signal (angular velocity signal) corresponding to the magnitude and direction of the detected three-axis angular velocity.

[0158] In the liquid crystal display (LCD) constituting the display module 1402, according to various detection modes, for example, position information using the GPS sensor 1411 and the geomagnetic sensor 1412, motion information such as the amount of movement using the acceleration sensor 1408 and the angular velocity sensor 1409 included in the movement amount or MEMS accelerometer 1, biological information such as the pulse rate using the pulse sensor 1413, or time information such as the current time, etc., can be displayed. In addition, the ambient temperature using the temperature sensor 1414 can also be displayed.

[0159] The communication module 1415 performs various controls for establishing communication between the user terminal and an information terminal (not shown). The communication module 1415 is configured to include, for example, a transceiver corresponding to a short-range wireless communication standard such as Bluetooth (registered trademark) (including BTLE: Bluetooth Low Energy), WFi (registered trademark) (Wireless Fidelity), Zigbee (registered trademark), NFC (Near field Communication), ANT+ (registered trademark), and a connector corresponding to a communication bus standard such as USB (Universal Serial Bus).

[0160] The processing module 1410 (processor) is composed of, for example, an MPU (Micro Processing Unit), a DSP (Digital Signal Processor), an ASIC (Application Specific Integrated Circuit), etc. The processing module 1410 performs various processes based on the program stored in the storage module 1416 and the signal input from the operation module 1417 (for example, the operation buttons 1406 and 1407). The processing by the processing module 1410 includes data processing for each output signal of the GPS sensor 1411, the geomagnetic sensor 1412, the pressure sensor 1418, the acceleration sensor 1408, the angular velocity sensor 1409, the pulse sensor 1413, the temperature sensor 1414, and the timing module 1419, display processing for causing the display module 1402 to display an image, sound output processing for causing the sound output module 1420 to output sound, communication processing for communicating with the information terminal via the communication module 1415, and power control processing for distributing the power from the battery 1421 to each module.

[0161] Such an activity meter 1400 can have at least the following functions.

[0162] 1. Distance: The total distance from the start of measurement is measured using the high-precision GPS function.

[0163] 2. Pace: Displays the current travel pace, starting from the pace distance measurement.

[0164] 3. Average speed: Calculates and displays the average speed from the start of the average speed running to the current time.

[0165] 4. Altitude: Measure and display the altitude through GPS function.

[0166] 5. Stride length: Stride length is measured and displayed even in tunnels where GPS radio waves cannot reach.

[0167] 6. Frequency: measures and displays the number of steps per minute.

[0168] 7. Heart rate: Measure and display heart rate through pulse sensor.

[0169] 8. Slope: Measure and display the slope of the ground during mountain training and trail running.

[0170] 9. Automatic laps: Automatically measure laps after walking a preset distance and time.

[0171] 10. Exercise calories consumed: Displays calories consumed.

[0172] 11. Steps: Displays the total number of steps since the start of exercise.

[0173] Such an actimeter 1400 (portable electronic device) includes: a MEMS accelerometer 1, a housing 1403 housing the MEMS accelerometer 1, a processing module 1410 housed in the housing 1403 and processing output data from the MEMS accelerometer 1, a display module 1402 housed in the housing 1403, and a light-transmitting cover 1404 covering an opening module of the housing 1403. Therefore, the effect of the above-mentioned MEMS accelerometer 1 can be enjoyed, and high reliability can be exhibited.

[0174] In addition, the activity meter 1400 can be widely used in sports watches, runners' watches, runners' watches corresponding to multiple sports such as duathlon or triathlon, outdoor watches, and GPS watches equipped with a satellite positioning system such as GPS.

[0175] In addition, in the above description, the GPS (Global Positioning System) is used as the satellite positioning system, but other global navigation satellite systems (GNSS: Global Navigation Satellite System: Global Navigation Satellite System) can also be used. For example, one or more satellite positioning systems such as EGNOS (European Geostationar Satellite Navigation Overlay Service: European Geostationary Satellite Navigation Augmentation System), QZSS (Quasi Zenith Satellite System: Quasi Zenith Satellite System), GLONASS (Global Navigation Satellite System), GALILEO, BeiDou (BeiDou Navigation Satellite System: BeiDou Navigation Satellite System) can also be used.

[0176] Furthermore, a geostationary satellite navigation augmentation system (SBAS: Satellite based Augmentation System) such as WAAS (Wide Area Augmentation System) or EGNOS (European Geostationary Satellite Navigation Overlay Service) may be used in at least one of the satellite positioning systems.

[0177] like Fig.17 As shown, the present invention provides a mobile body of some embodiments, including:

[0178] A MEMS accelerometer as described above; and a gesture control module.

[0179] Fig.17 The automobile 1500 shown is an automobile of a mobile body to which the present invention is applied. In the figure, a MEMS accelerometer 1 that functions as an acceleration sensor is built into the automobile 1500, and the MEMS accelerometer 1 can be used to detect the posture of the vehicle body 1501. The detection signal of the MEMS accelerometer 1 is supplied to the vehicle body posture control device 1502 (posture control unit), and the vehicle body posture control device 1502 detects the posture of the vehicle body 1501 based on the signal, and can control the hardness of the suspension and the brakes of each wheel 1503 according to the detection result. Here, as the MEMS accelerometer 1, for example, the same MEMS accelerometer as that in the above-mentioned embodiments can be used.

[0180] Such a car 1500 (moving object) includes the MEMS accelerometer 1 and the vehicle body posture control device 1502 (posture control unit). Therefore, the above-mentioned effects of the MEMS accelerometer 1 can be enjoyed, and high reliability can be exhibited.

[0181] The MEMS accelerometer 1 can also be widely used in electronic control units (ECUs) such as car navigation systems, car air conditioners, anti-lock braking systems (ABS), airbags, tire pressure monitoring systems (TPMS), engine controllers, and battery monitors for hybrid vehicles or electric vehicles.

[0182] In addition, the mobile object is not limited to the automobile 1500, and can also be applied to, for example, airplanes, rockets, artificial satellites, ships, AGVs (automatic guided vehicles), bipedal walking robots, unmanned aerial vehicles such as drones, and the like.

[0183] In summary, the MEMS accelerometer and its application of the present invention only require two etchings on a single side, which simplifies the process, improves the yield of finished products, and saves money and time costs; the introduced lever structure greatly improves the measurement sensitivity without affecting the range of the accelerometer, which is beneficial to improving the dynamic range of the accelerometer; it is easy to perform multi-axis monolithic integration, which brings space and cost advantages for spatial acceleration motion measurement.

[0184] Each embodiment in this specification is described in a progressive manner, and the same or similar parts of each embodiment can be directly referenced to each other, and each embodiment focuses on the differences from other embodiments. It should be noted that the technical features of the above-mentioned embodiments can be combined arbitrarily. In order to make the description concise, not all possible combinations of the technical features in the above-mentioned embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0185] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and substitutions can be made without departing from the technical principles of the present invention. These improvements and substitutions should also be regarded as the scope of protection of the present invention.

Claims

1. A microelectromechanical system (MEMS) accelerometer, characterized in that: include: substrate; A plurality of units disposed on the substrate; The unit comprises: A mass block, the mass block is spaced from the plane where the substrate is located, and is configured to be displaceable along a first direction parallel to the substrate under the action of a first acceleration; A lever structure, the lever structure is connected to the base plate, and the lever structure is connected to the mass block in a plane parallel to the base plate; a plurality of fixed electrode fingers, the fixed electrode fingers being connected to the substrate and being arranged on a first side of the mass block in a second direction, the fixed electrode fingers extending along the second direction, wherein the second direction is parallel to the substrate and orthogonal to the first direction; A movable electrode, the movable electrode is arranged on a first side of the mass in the second direction and connected to the lever structure, each of the movable electrodes comprising a plurality of movable electrode fingers; The lever structure is configured to drive each movable electrode finger to undergo a second displacement along the first direction between every two fixed electrode fingers along with the first displacement of the mass block in the first direction, wherein an absolute value of the second displacement is greater than an absolute value of the first displacement.

2. The MEMS accelerometer according to claim 1, characterized in that: There are two lever structures, and the two lever structures are respectively connected to a first side portion and a second side portion of the mass block that are opposite to each other in the first direction.

3. The MEMS accelerometer according to claim 2, characterized in that: The lever structure is connected to the mass block at a first side portion and a second side portion of the mass block close to the first side, and extends toward the first side along a second direction.

4. The MEMS accelerometer according to claim 3, characterized in that: The lever structure is a primary lever structure, comprising a lever and a fulcrum, wherein the fulcrum is connected to the substrate, wherein in a first direction, the lever is connected to the fulcrum, and in a second direction, a first end of the lever is connected to the mass block, and a second end of the lever is away from the mass block along the second direction and connected to the movable electrode, and a distance between the fulcrum and the first end is smaller than a distance between the fulcrum and the second end.

5. The MEMS accelerometer according to claim 3, characterized in that: The lever structure is a two-stage lever structure, in which each stage of the lever structure comprises a lever and a fulcrum connected to each other, and the fulcrum of each stage of the lever structure is connected to the substrate; The lever in each level of the lever structure has a first end close to the mass block and a second end away from the mass block along the second direction, and the distance between the fulcrum and the first end is smaller than the distance between the fulcrum and the second end; The first end of the lever in the first-level lever structure is connected to the mass block, the second end of the lever in the first-level lever structure is connected to the first end of the lever in the second-level lever structure, and the second end of the lever in the second-level lever structure is connected to the movable electrode.

6. The MEMS accelerometer according to claim 3, characterized in that: The lever structure is a multi-stage lever structure, in which each stage of the lever structure comprises a lever and a fulcrum connected to each other, and the fulcrum of each stage of the lever structure is connected to the substrate; The lever in each level of the lever structure has a first end close to the mass block and a second end away from the mass block along the second direction, and the distance between the fulcrum and the first end is smaller than the distance between the fulcrum and the second end; The first end of the lever in the first-stage lever structure is connected to the mass block; The first end of the lever in the last lever structure is connected to the second end of the lever in the second lever structure, and the second end of the last lever structure is connected to the movable electrode; In the multi-stage lever structure between the first-stage lever structure and the last-stage lever structure, the first ends of the levers in the next-stage lever structure are connected to the second ends of the levers in the previous-stage lever structure.

7. The MEMS accelerometer according to claim 3, characterized in that: The first end of the lever is connected to the mass block via a connecting member that can be telescopic along the first direction.

8. The MEMS accelerometer according to claim 5 or 6, characterized in that: The first end of the lever in the first-stage lever structure is connected to the mass block via a connecting member that can be telescopic along the first direction.

9. The MEMS accelerometer according to any one of claims 4 to 6, characterized in that: The lever is connected to the fulcrum via a bridge extending along the first direction.

10. The MEMS accelerometer according to claim 1, characterized in that: Every two of the fixed electrode fingers are connected to the substrate via a supporting base, and the fixed electrode fingers extend along the second direction.

11. The MEMS accelerometer according to any one of claims 1 to 3, characterized in that: The movable electrode includes a connecting rod and a movable electrode finger, the connecting rod is connected to the lever structure and extends from the lever structure along the first direction, the movable electrode finger is arranged on one side of the connecting rod along the first direction, and the movable electrode finger extends along the second direction.

12. The MEMS accelerometer according to claim 11, characterized in that: There are two lever structures, and each connecting rod is provided with a movable electrode finger.

13. The MEMS accelerometer according to any one of claims 1 to 3, characterized in that: The movable electrode includes a connecting rod and a movable electrode finger, the connecting rod is connected to the lever structure and extends from the lever structure along the first direction, the movable electrode finger is arranged on both sides of the connecting rod along the first direction, and the movable electrode finger extends along the second direction.

14. The MEMS accelerometer according to claim 12, characterized in that: There are two lever structures, and the two movable electrode fingers are arranged on both sides of the connecting rod along the first direction.

15. The MEMS accelerometer according to any one of claims 1 to 3, characterized in that: The unit also includes: A fixed electrode is disposed on the substrate and within a projection range of the mass block on the substrate, and the mass block is configured to be displaceable along a third direction perpendicular to the substrate under the action of a second acceleration.

16. A microelectromechanical system (MEMS) accelerometer, characterized in that: include: substrate; A plurality of units disposed on the substrate; The unit comprises: A mass block, the mass block is spaced from the plane where the substrate is located, and is configured to be displaceable along a first direction parallel to the substrate under the action of a first acceleration; a lever structure, the lever structure being connected to the substrate, the lever structure being disposed on a first side of the mass block along a second direction, the second direction being parallel to the substrate and being orthogonal to the first direction, one end of the lever structure being connected to the mass block at a side of the mass block close to the first side, and the other end of the lever structure extending away from the mass block along the second direction; a plurality of fixed electrode fingers, the fixed electrode fingers being connected to the substrate and being arranged on a first side of the mass block in the second direction; A movable electrode, the movable electrode is arranged on a first side of the mass block in the second direction, each of the movable electrodes comprises a plurality of movable electrode fingers, and the movable electrode fingers are connected to the other end of the lever structure away from the mass block; The unit is configured to obtain the acceleration of the mass block moving along the first direction based on the capacitance change caused by the displacement of each movable electrode finger along the first direction between two fixed electrode fingers, wherein the displacement along the first direction is driven by the movement of the lever structure, and the movement of the lever structure is driven by the displacement of the mass block along the first direction.

17. The MEMS accelerometer according to claim 16, characterized in that: The lever structure is connected to the mass block via a connecting member that can be telescopic along the first direction.

18. The MEMS accelerometer according to claim 16, characterized in that: The movable electrode is connected to the other end of the lever structure away from the mass block, and the movable electrode includes a connecting rod and a movable electrode finger. The connecting rod is connected to the lever structure and extends from the lever structure along the first direction, and the movable electrode finger is connected to the connecting rod and extends along the second direction.

19. The MEMS accelerometer according to claim 16, characterized in that: Every two of the fixed electrode fingers are connected to the substrate via a supporting base, and the fixed electrode fingers extend along the second direction.

20. The MEMS accelerometer according to claim 16, wherein: The lever structure is a multi-stage lever structure, in which each stage of the lever structure comprises a lever and a fulcrum connected to each other, and the fulcrum of each stage of the lever structure is connected to the substrate; The lever in each level of the lever structure has a first end close to the mass block and a second end away from the mass block along the second direction, and the distance between the fulcrum and the first end is smaller than the distance between the fulcrum and the second end.

21. The MEMS accelerometer according to claim 16, wherein: There are two lever structures, and the two lever structures are respectively connected to a first side portion and a second side portion of the mass block that are opposite to each other in the first direction.

22. A MEMS accelerometer device, characterized in that: include: A MEMS accelerometer according to any one of claims 1 to 15; and circuit components.

23. A MEMS accelerometer device, characterized in that: include: A MEMS accelerometer according to any one of claims 16 to 21; and circuit components.

24. An electronic device, characterized in that: include: A MEMS accelerometer according to any one of claims 1 to 15; Control circuit; and correction circuit.

25. An electronic device, characterized in that: include: A MEMS accelerometer according to any one of claims 16 to 21; Control circuit; and correction circuit.

26. A portable electronic device, characterized in that: include: A MEMS accelerometer according to any one of claims 1 to 15; A housing for accommodating the MEMS accelerometer; A processing module, housed in the housing, for processing output data from the MEMS accelerometer; A display module, housed in the housing; as well as The light-transmitting cover covers the opening module of the housing.

27. A portable electronic device, characterized in that: include: A MEMS accelerometer according to any one of claims 16 to 21; A housing for accommodating the MEMS accelerometer; A processing module, housed in the housing, for processing output data from the MEMS accelerometer; A display module, housed in the housing; as well as The light-transmitting cover covers the opening module of the housing.

28. A mobile object, characterized in that: include: A MEMS accelerometer according to any one of claims 1 to 15; and attitude control module.

29. A mobile object, characterized in that: include: A MEMS accelerometer according to any one of claims 16 to 21; and attitude control module.

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