CN105584984B - Micro-electromechanical device - Google Patents

Abstract

The present invention provides a micro-electromechanical device, which comprises: a substrate; a mass block, comprising at least two grooves, each groove having an internal space and an opening, wherein the internal space is relatively closer to the middle part of the mass block than the opening; at least two anchor points, located in corresponding grooves and connected to the substrate; at least two connecting rods, located in corresponding grooves and connected to corresponding anchor points; and a multi-dimensional motion elastic structure, which is used to assist the mass block in performing multi-dimensional motion, wherein the multi-dimensional motion elastic structure is located at the periphery of the mass block and is connected to the substrate through the at least two connecting rods and the at least two anchor points, and wherein the multi-dimensional motion elastic structure comprises a plurality of first springs and a plurality of second springs, so as to assist the mass block in performing motion in out-of-plane and in-plane directions.

Description

MEMS

technical field

The invention relates to a micro-electro-mechanical device, in particular to a micro-electro-mechanical device that provides and senses the multi-dimensional motion of the mass block through one of the mass blocks and a multi-dimensional motion elastic structure connected to an anchor point located in the middle of the mass block.

Background technique

Micro-electro-mechanical devices have been widely used in daily life, and motion sensing is a common application in micro-electro-mechanical devices. FIG. 1 shows a MEMS device 10 in the prior art (US Pat. No. US 8,459,114), in which three mass blocks 11, 12, 13 are used to sense three-dimensional motions respectively. However, the quality and size of the mass blocks 11, 12, and 13 are different, so the three-dimensional motion sensing needs to have different designs to meet the requirements of different quality and size. The anchor points connecting the fixed ends 14 of the mass blocks 11, 12, 13 are not all set in the middle, regardless of the operating environment or the temperature difference in the manufacturing process, the design of the anchor points connecting the two sides may be deformed due to stress, thereby affecting the accuracy of sensing .

FIG. 2 shows a microelectromechanical device 20 of another prior art (US Patent No. US 7,637,160), its mass 21 is fixed on the substrate 23 through the anchor points 22 on both sides of the Y direction, and its sensing direction is parallel to the substrate Parallel coplanar directions (in-plane, X, Y directions, FIG. 2 ) cannot sense three-dimensional motion, and it still has the possibility of distortion.

Fig. 3 shows a MEMS 30 of another prior art (US Pat. One-third of the partial view), its mass block 31 is connected to the substrate (not shown in the figure) through a spring 33, a connecting rod 32, and a plurality of anchor points 34, and special attention should be paid to the connection of its connecting rod 32 through a plurality of anchor points 34 In order to avoid deformation or twisting of the substrate, although it partially solves the problem of deformation or twisting, this design limits the movement of the mass block 31 (two-dimensional movement in the same plane) and increases manufacturing complexity, which limits its application.

In a word, the MEMS devices in the prior art are either unable to perform 3D sensing, or although capable of 3D sensing, they cannot withstand large stress and are easily deformed to cause offset. Therefore, the present invention aims at the shortcomings of the prior art, and proposes a micro-electro-mechanical device capable of sensing multi-dimensional motion and having low deflection after being subjected to stress.

Contents of the invention

The purpose of the present invention is to overcome the deficiencies and defects of the prior art, and propose a MEMS device capable of sensing multi-dimensional motion and having low deflection after being subjected to stress.

In order to achieve the above object, on one of the viewpoints, the present invention provides a micro-electro-mechanical device, which includes: a substrate; a mass block, including at least two grooves, each groove has an inner space and an opening, and the inner space is opposite to each other. closer to the middle portion of the mass than the opening; at least two anchor points, located in corresponding grooves, connected to the substrate; at least two connecting rods, located in corresponding grooves, connected to corresponding anchor points; and A multi-dimensional motion elastic structure is used to assist the mass block to perform multi-dimensional motion. The multi-dimensional motion elastic structure is located on the periphery of the mass block and is connected to the substrate through the at least two connecting rods and the at least two anchor points. The multi-dimensional motion The elastic structure includes a plurality of first springs to connect the mass block and assist the mass block to move in an out-of-plane direction; and a plurality of second springs, each second spring is directly or indirectly connected to a corresponding connecting rod and the first spring to assist the mass block to move in the same plane direction.

In one embodiment, the at least two grooves, the at least two connecting rods and the at least two anchor points are arranged symmetrically.

In one embodiment, the plurality of first springs are connected to two opposite sides of the mass block, and the openings of the at least two grooves are connected to the other two opposite sides of the mass block.

In one embodiment, the plurality of first springs are a plurality of rotation springs to assist the mass to perform a rotation movement.

In one embodiment, the plurality of rotating springs form a rotating axis, and the mass of the mass block is unevenly distributed on both sides of the rotating axis, so that the rotating motion is an eccentric motion.

In one embodiment, the plurality of first springs are a plurality of translation springs to assist the mass mass to perform a translational movement in an out-of-plane direction.

In one embodiment, multiple anchor points are provided in each groove, and each connecting rod is connected to all the anchor points in the same groove.

In one embodiment, the multi-dimensional motion elastic structure has a frame structure, and the mass block is located in an inner space of the frame structure.

In one embodiment, the multi-dimensional motion elastic structure includes: an outer frame structure with an inner space for accommodating the mass block; at least two inner brackets connected to at least two corresponding connecting rods; and the aforementioned plurality of first A spring and a plurality of second springs, the outer frame structure connects inwardly to the inner support via the second spring, and connects to the mass block inwardly via the first spring, wherein the inner support and the outer frame structure do not contain part of mass.

The following will be described in detail through specific embodiments, so that it is easier to understand the purpose, technical content, characteristics and effects of the present invention.

Description of drawings

Figures 1, 2, and 3 show three MEMS devices of the prior art;

4A and 4B show a schematic diagram of a microelectromechanical device and a schematic diagram of parts thereof according to an embodiment of the present invention;

FIG. 4C shows a schematic diagram of a multi-dimensional kinematic elastic structure according to an embodiment of the present invention;

5 and 6 show schematic diagrams of MEMS devices according to various embodiments of the present invention.

Explanation of symbols in the figure

10 microelectromechanical devices

11, 12, 13 masses

14 fixed end

20 microelectromechanical devices

21 masses

22 anchor points

23 Substrate

31 masses

32 connecting rod

33 springs

34 anchor points

40 microelectromechanical devices

41 substrate

42 masses

421 Groove

4211 interior space

4212 opening

43 Multidimensional Kinematic Elastic Structures

431 interior space

432 inner bracket

433 frame structure

44 connecting rod

45 anchor points

46 grooves

50 microelectromechanical devices

51 Multidimensional Kinematic Elastic Structures

52 masses

60 microelectromechanical devices

61 connecting rod

AA’, BB’ axes

M1 Rotation Elastic Motion

M2, M3 translational elastic motion

S1 first spring

S2 second spring

X, Y, Z direction

Detailed ways

The foregoing and other technical contents, features and effects of the present invention will be clearly presented in the following detailed description of a preferred embodiment with reference to the drawings. The directional terms mentioned in the following embodiments, such as: up, down, left, right, front or back, etc., are only directions referring to the attached drawings. The drawings in the present invention are all schematic, mainly intended to show the functional relationship between each device and each component, as for the shape, thickness and width, they are not drawn to scale.

4A-4C, the present invention provides a MEMS device 40, which includes: a substrate 41; a mass 42, which contains at least two grooves 421 inside, each groove 421 has an internal space 4211 and an opening 4212 (See Figure 4B, which is a partial view of Figure 4A), the inner space 4211 is relatively closer to the middle part of the mass block 42 than the opening 4212, and the opening 4212 is connected to the edge of the mass block 42 and opens outward; at least two connecting rods 44 and at least two anchor points 45, the connecting rod 44 and the anchor point 45 are located in the groove 421 and connected correspondingly; and a multi-dimensional motion elastic structure 43 (referring to Fig. 4C, wherein the solid line part shows the multi-dimensional motion elastic structure 43, and the dotted line part Show other structures other than the multi-dimensional motion elastic structure 43), located on the periphery of the mass block 42, the multi-dimensional motion elastic structure 43 is connected with the substrate 41 through at least two connecting rods 44 and at least two anchor points 45 (in each groove in FIG. 4A A plurality of anchor points 45 are shown in the groove 421, and the connecting rod 44 may be connected to all the anchor points 45 in the same groove 421), and the multi-dimensional motion elastic structure 43 includes a plurality of first springs connected to the mass block 42 S1 is to assist the mass block 42 to move out of the plane (for example: rotational elastic movement M1 in FIG. 4A ). The multi-dimensional motion elastic structure 43 includes a plurality of second springs S2 in its internal structure to assist the mass block 42 to perform coplanar motion (for example: translational elastic motion M2, M3 in FIG. 4A ), the plurality of second springs S2 directly or indirectly It is connected between the connecting rod 44 and the first spring S1. In a preferred embodiment, the at least two grooves 421 , the at least two connecting rods 44 and the at least two anchor points 45 are arranged symmetrically. Moreover, in a preferred embodiment, the plurality of first springs S1 are connected to two opposite sides of the mass block 42 , and the opening 4212 of the groove 421 is connected to the other two opposite sides of the mass block 42 .

The mass 42 itself constitutes a movable electrode, while the MEMS device 40 is provided with fixed electrodes in appropriate relative positions. When the mass 42 moves, the capacitance value between the movable electrode and the fixed electrode changes, so that the movement of the MEMS device 40 can be sensed. This point is well known to those skilled in the art, so the detailed description of related technologies and the illustration of the fixed electrodes are omitted; the positions of the fixed electrodes can be designed and arranged according to requirements.

In one embodiment, the mass block 42 included in the MEMS device 40 is a single mass block, but the present invention is not limited thereto, and the mass block 42 can also be divided into at least two mass blocks (not shown) that are not directly connected, for example But it is not limited to make the at least two mass blocks respectively sense motions in different directions.

Referring to FIG. 4A , in one embodiment, the multi-dimensional elastic motion of the mass block is an eccentric motion. With respect to the axis AA' formed by the first spring S1, the mass of the mass 42 is not evenly distributed on both sides thereof, so when the mass 42 rotates around the axis AA', an eccentric motion occurs. The method of distributing the mass of the proof mass 42 unevenly, for example, simply makes the axis AA' not located on the geometric center line of the proof mass 42 . In another embodiment, for example but not limited to, grooves 46 may be provided in the mass block 42 to achieve the effect of unevenly distributing the mass of the mass block 42 . The grooves 46 shown in FIG. 4A are only illustrative, and the number, shape or position of the grooves 46 can be changed. Since the mass of the mass block 42 is not evenly distributed on both sides of the axis AA', when the mass block 42 moves in the same plane in the X direction on the X-Y plane, it will also constitute an eccentric motion.

In addition, relative to the axis BB', it is also possible to design that the mass of the mass block 42 is not evenly distributed on both sides, so that when the mass block 42 moves in the same plane in the Y direction on the X-Y plane, it will also move eccentrically.

The above-mentioned eccentric motion can improve the accuracy of sensing by means of a differential method, but the present invention is not limited thereto, and the motion of the mass block 42 in all dimensions may not be eccentric motion, but pure translational motion.

For example, FIG. 5 shows a microelectromechanical device 50 of another embodiment, wherein the mass block 52 cannot rotate along the first spring S1, so the out-of-plane direction of the mass block 52 (the Z direction is perpendicular to the X-Y plane) Out-of-plane direction) movement is only translational movement. In order to avoid shape variation caused by thermal deformation, the positions of the two first springs S1 on the left and right can be arranged as close as possible to the middle position, for example, the two first springs S1 are arranged within the middle third of the left and right sides of the mass block 52, or When the thermal deformation conditions are relatively severe, for example, the two first springs S1 are arranged within the middle quarter of the left and right sides of the mass block 52, and the range depends on the design requirements and is not limited to the above-mentioned embodiments. limits.

In the aforementioned embodiments, the multi-dimensional elastic motion is exemplified by three-dimensional elastic motion, but the implementation is not limited to three-dimensional, but can be two-dimensional (for example, the structure is the same, but the fixed electrodes in one of the X, Y, and Z directions are reduced without detection. Detect the movement of this dimension), or it can be more than three-dimensional (for example, increase the detection of angular velocity or gravity, etc.). The number of dimensions of the multi-dimensional elastic motion can be changed according to needs, without being limited to the aforementioned implementation content.

The main function of the multi-dimensional motion elastic structure 43 is to elastically connect the mass block 42 to enable multi-dimensional elastic motion, and to connect the mass block 42 to the anchor point 45 located in the internal groove 421 of the mass block 42 . It is only necessary to achieve the above functions, and the structural layout of the multi-dimensional motion elastic structure 43 can be in any suitable manner. 4A, 4C, in a preferred embodiment, the multi-dimensional motion elastic structure 43 has a frame structure, and the mass block 42 is located in an inner space 431 of the frame structure. In detail, the multi-dimensional motion elastic structure 43 includes: an outer frame structure 433, which has an inner space 431 to accommodate the mass block 42; at least two inner brackets 432, connected to at least two corresponding connecting rods 44, through the corresponding At least two connecting rods 44 and corresponding at least two anchor points 45 are connected to a substrate 41 of the MEMS device 40, and the anchor points 45 are located in the groove 421 of the mass block 42; and a plurality of first springs S1 and second springs S2 , the outer frame structure 433 is inwardly connected to the inner support 432 via the second spring S2, and is inwardly connected to the mass block 42 via the first spring S1, so as to assist the mass block 42 to perform multi-dimensional elastic movements M1, M2, M3, the inner support 432 and A part of the proof mass 42 is not included between the outer frame structures 433 . In this way, the multi-dimensional motion elastic structure 43 has a frame structure, and the mass block 42 is located in an inner space 431 of the frame structure.

In the embodiment shown in Figures 4A, 4C, 5, the link 44 has a rectangular or rectilinear shape. The MEMS device 60 in FIG. 6 has a connecting rod 61 according to another embodiment, which shows that the embodiment of the connecting rod is not limited to the aforementioned geometric shape, but depends on the requirements for the connection between the anchor point and the elastic structure with multi-dimensional motion. In addition, the shape of the trench is not limited to those shown in FIGS. 4A-4C and 5 .

The present invention has been described above with reference to preferred embodiments, but the above description is only for those skilled in the art to easily understand the content of the present invention, and is not intended to limit the scope of rights of the present invention. Various equivalent changes within the spirit of the invention will immediately occur to those skilled in the art. Therefore, all equivalent changes or modifications made according to the concept and spirit of the present invention shall be included in the scope of the claims of the present invention. It is not necessary for any embodiment or claim of the present invention to achieve all the disclosed objects or advantages or features of the present invention. The abstract part and the title are only used to assist the search of patent documents, and are not used to limit the scope of rights of the present invention.

Claims (9)

1. A microelectromechanical device, characterized in that it comprises: a substrate; A mass comprising at least two grooves, each of which has an inner space and an opening, the inner space being relatively closer to the middle portion of the mass than the opening; At least two anchor points are located in the corresponding grooves and connected to the substrate, wherein the anchor points are located in the inner space of the grooves, close to the middle part of the proof mass; At least two connecting rods are located in corresponding grooves and connected with corresponding anchor points; A multi-dimensional motion elastic structure is used to assist the mass block to perform multi-dimensional motion. The multi-dimensional motion elastic structure is located on the periphery of the mass block and is connected to the substrate through the at least two connecting rods and the at least two anchor points. The multi-dimensional motion The elastic structure contains: A plurality of first springs are used to connect the mass and assist the mass to move in an out-of-plane direction; and A plurality of second springs, each second spring is directly or indirectly connected between a corresponding connecting rod and the first spring to assist the mass block to move in the same plane direction; Wherein, the plurality of first springs are connected to two opposite sides of the mass block, and the openings of the at least two grooves are connected to the other two opposite sides of the mass block; and An outer frame structure, which has an inner space to accommodate the mass block, the outer frame structure is connected with the first spring and the second spring, and the second spring is connected to the outer frame through the first spring Structural connections. 2. The micro-electro-mechanical device as claimed in claim 1, wherein the at least two grooves, the at least two connecting rods and the at least two anchor points are all arranged in a mirror-symmetric manner. 3. The MEMS device as claimed in claim 1, wherein the plurality of first springs are a plurality of rotation springs to assist the mass to perform a rotation movement. 4. The micro-electro-mechanical device as claimed in claim 3, wherein the plurality of rotating springs form a rotating axis, and the masses of the proof mass are unevenly distributed on both sides of the rotating axis, so that the rotating motion is an eccentric motion. 5. The MEMS device as claimed in claim 1, wherein the plurality of first springs are a plurality of translation springs for assisting the translational movement of the mass in the out-of-plane direction. 6. The MEMS device as claimed in claim 1, wherein a plurality of anchor points are provided in each groove, and each connecting rod is connected to all the anchor points in the same groove. 7. The MEMS device as claimed in claim 1, wherein the multi-dimensional motion is a three-dimensional motion. 8. The MEMS device as claimed in claim 1, wherein the multi-dimensional motion elastic structure has a frame structure, and the mass block is located in an inner space of the frame structure. 9. The MEMS device according to claim 1, wherein the multi-dimensional motion elastic structure comprises: at least two inner brackets connected to corresponding at least two connecting rods; and The above-mentioned multiple first springs and multiple second springs, the outer frame structure is connected inwardly to the inner bracket via the second spring, and connected to the mass block inwardly via the first spring, wherein the inner bracket and the outer frame The inter-structure does not contain part of the mass.