Accelerometer with beams and anchor points outside structure

Abstract

The utility model provides an accelerometer with beams and anchor points on the outer side of a structure, a substrate layer is in an XY plane, and a device layer is located above the substrate layer; the movable mass block is located in the middle of the substrate layer and connected with an outer frame anchored to the substrate layer through anchor points through a first elastic beam unit, a second elastic beam unit, a third elastic beam unit and a fourth elastic beam unit. The first elastic beam unit and the third elastic beam unit are connected through a coupling beam unit which is parallel to the X axis and located on the upper side and the lower side of the movable mass block, and the second elastic beam unit and the fourth elastic beam unit are connected through a coupling beam unit. The detection capacitor structure is respectively connected with the movable mass block and the substrate layer in the middle area of the movable mass block; when the movable mass block moves in the X-axis direction, the capacitance value of the detection capacitor structure changes, so that acceleration detection is achieved, and the accelerometer which can have good dynamic output stability under the condition that the sensitivity of the accelerometer is large is provided.

Description

TECHNICAL FIELD

[0001] The utility model relates to sensor microstructure technical field especially relates to a beam and anchor point are in the accelerometer of structure outside side. BACKGROUND

[0002] Capacitive accelerometer is based on hooke's law, utilizes external acceleration to change the displacement of sensitive mass, and further transforms into the variation of capacitance to measure. The common translational accelerometer beam structure at present mainly is S type beam, in order to guarantee the stability of accelerometer output and reduce cross-axis sensitivity, when designing, it is desired to guarantee that the working modal frequency and the parasitic modal frequency are as far as possible bigger, this requires that the number of turns and the length of S type elastic beam are not suitable to design too long, this restriction greatly restricts the sensitivity of accelerometer.

[0003] Therefore, it is required to provide an accelerometer structure design technical scheme that can have better dynamic output stability under the condition of greater accelerometer sensitivity. SUMMARY

[0004] To solve the above technical problem, the utility model provides a beam and anchor point are in the accelerometer of structure outside side.

[0005] The utility model provides a beam and anchor point are in the accelerometer of structure outside side, including substrate layer and device layer;

[0006] The plane where substrate layer is located is XY plane, and device layer is located above substrate layer;

[0007] Device layer includes anchor point, movable mass, first elastic beam unit, second elastic beam unit, third elastic beam unit, fourth elastic beam unit, coupling beam unit, detection capacitance structure and outer frame;

[0008] The outer frame is anchored at the edge of substrate layer through four anchor points;

[0009] Movable mass is located in the middle of substrate layer, and is connected with the left side of outer frame through first elastic beam unit and second elastic beam unit respectively on the left side;

[0010] The first elastic beam unit and the third elastic beam unit are connected by one coupling beam unit parallel to the X axis on the upper side of the movable mass block, and the second elastic beam unit and the fourth elastic beam unit are connected by another coupling beam unit parallel to the X axis on the lower side of the movable mass block.

[0011] The detection capacitor structure is anchored on the substrate layer in the middle region of the movable mass block and is connected with the movable mass block.

[0012] When the movable mass block moves along the X axis direction, the capacitance value of the detection capacitor structure changes, so as to realize the detection of acceleration.

[0013] In a possible implementation, the coupling beam unit comprises at least one coupling beam.

[0014] The first elastic beam unit, the second elastic beam unit, the third elastic beam unit and the fourth elastic beam unit are the same elastic beam unit.

[0015] The elastic beam unit comprises at least one elastic beam.

[0016] In a possible implementation, the elastic beam is S-shaped.

[0017] In a possible implementation, the coupling beam is a straight beam.

[0018] In a possible implementation, the detection capacitor structure comprises a plurality of detection capacitor units.

[0019] The detection capacitor unit comprises movable comb teeth fixed to the movable mass block and fixed comb teeth anchored to the substrate layer.

[0020] The technical scheme provided by the utility model has at least the following beneficial effects:

[0021] The first elastic beam unit and the third elastic beam unit are connected by one coupling beam unit parallel to the X axis on the upper side of the movable mass block, and the second elastic beam unit and the fourth elastic beam unit are connected by another coupling beam unit parallel to the X axis on the lower side of the movable mass block, so that the accelerometer has better dynamic output characteristics, cross-axis sensitivity is reduced, and the overall impact resistance is improved. BRIEF DESCRIPTION OF DRAWINGS

[0022] Figure 1 The first overall structure schematic view of the accelerometer with the beam and the anchor point on the structure outside is provided for the utility model embodiment;

[0023] Figure 2 The structure schematic view of the detection capacitor unit is provided for the utility model embodiment;

[0024] Figure 3 A first partial structure schematic view of an accelerometer with a beam and an anchor point outside a structure is provided for the embodiment of the utility model;

[0025] Figure 4 A second partial structure schematic view of an accelerometer with a beam and an anchor point outside a structure is provided for the embodiment of the utility model;

[0026] Figure 5 A third partial structure schematic view of an accelerometer with a beam and an anchor point outside a structure is provided for the embodiment of the utility model;

[0027] Figure 6 A second overall structure schematic view of an accelerometer with a beam and an anchor point outside a structure is provided for the embodiment of the utility model;

[0028] Figure 7 A third overall structure schematic view of an accelerometer with a beam and an anchor point outside a structure is provided for the embodiment of the utility model;

[0029] Figure 8 A side view partial structure schematic view among a substrate layer, an anchor point and an outer frame is provided for the embodiment of the utility model;

[0030] In the drawing, 10, substrate layer;11, anchor point;12, movable mass;13, first elastic beam unit;14, second elastic beam unit;15, third elastic beam unit;16, fourth elastic beam unit;17, coupling beam unit;18, detection capacitance structure;19, outer frame;181, movable comb teeth;182, fixed comb teeth. DETAILED DESCRIPTION

[0031] In order to deepen the understanding of the utility model, the utility model will be further described in detail below in conjunction with the drawings and embodiments, and the embodiments are only used to explain the utility model and do not constitute the limitation to the protection scope of the utility model.

[0032] Please refer to Figures 1 to 8 The utility model provides an accelerometer with a beam and an anchor point outside a structure, including substrate layer 10 and device layer;

[0033] The plane where substrate layer 10 is located is XY plane, and the device layer is located above substrate layer 10;

[0034] The device layer includes anchor point 11, movable mass 12, first elastic beam unit 13, second elastic beam unit 14, third elastic beam unit 15, fourth elastic beam unit 16, coupling beam unit 17, detection capacitance structure 18 and outer frame 19;

[0035] The outer frame 19 is anchored at the edge of the substrate layer 10 by four anchor points 11;

[0036] The movable mass 12 is located in the middle of the substrate layer 10, and is connected to the left side of the outer frame 19 by the first elastic beam unit 13 and the second elastic beam unit 14 respectively, and is connected to the right side of the outer frame 19 by the third elastic beam unit 15 and the fourth elastic beam unit 16 respectively;

[0037] The first elastic beam unit 13 and the third elastic beam unit 15, and the second elastic beam unit 14 and the fourth elastic beam unit 16 are connected by a coupling beam unit 17 respectively, which is parallel to the X axis and located on the upper and lower sides of the movable mass 12;

[0038] The detection capacitor structure 18 is anchored on the substrate layer 10 in the middle region of the movable mass 12 and is connected to the movable mass 12;

[0039] When the movable mass 12 moves along the X axis direction, the capacitance value of the detection capacitor structure 18 changes, thereby achieving the detection of acceleration.

[0040] In a specific embodiment, the substrate layer 10 can be rectangular. The anchor points 11 can be square, and four anchor points 11 are respectively arranged at the four corners of the substrate layer 10, and the four anchor points 11 support the outer frame 19 on the substrate layer 10. The outer frame 19 surrounds the periphery of the components such as the movable mass 12, the first elastic beam unit 13, the second elastic beam unit 14, the third elastic beam unit 15, the fourth elastic beam unit 16, the coupling beam unit 17, and the detection capacitor structure 18. The connection relationship between the anchor points 11 and the outer frame 19 and the substrate layer 10 can be referred to Figure 8The movable mass 12 is located in the center of the substrate layer 10. The first elastic beam unit 13, the second elastic beam unit 14, the third elastic beam unit 15 and the fourth elastic beam unit 16 are the same type of elastic beam units. The first elastic beam unit 13 and the second elastic beam unit 14 are symmetrically distributed above and below the movable mass 12 on the left side of the movable mass 12. The third elastic beam unit 15 and the fourth elastic beam unit 16 are symmetrically distributed above and below the movable mass 12 on the right side of the movable mass 12. The first elastic beam unit 13 and the third elastic beam unit 15 are symmetrically distributed on the left and right sides of the movable mass 12. The second elastic beam unit 14 and the fourth elastic beam unit 16 are symmetrically distributed on the left and right sides of the movable mass 12. One coupling beam unit 17 located on the upper side of the movable mass 12 parallel to the X axis connects the first elastic beam unit 13 and the third elastic beam unit 15. Another coupling beam unit 17 located on the lower side of the movable mass 12 parallel to the X axis connects the second elastic beam unit 14 and the fourth elastic beam unit 16. The coupling beam unit 17 connects the elastic beam units on the left and right sides of the movable mass 12, which can ensure that the accelerometer has a larger sensitivity and a better dynamic output characteristic, reduce the cross-axis sensitivity, and improve the overall impact resistance. A gap is formed in the middle region of the movable mass 12 and is in communication with the bottom substrate layer 10. A detection capacitor structure 18 is arranged in the gap. The detection capacitor structure 18 can adopt a comb structure, one part of which is fixed on the movable mass 12 and the other part of which is anchored on the substrate layer 10. In the working state, when the accelerometer is subjected to an external force, the movable mass 12 moves left or right along the X axis direction through inertia, and the capacitance value of the detection capacitor structure 18 changes, so that the acceleration detection can be realized.

[0041] In a possible implementation, the coupling beam unit 17 includes at least one coupling beam.

[0042] The first elastic beam unit 13, the second elastic beam unit 14, the third elastic beam unit 15 and the fourth elastic beam unit 16 are the same elastic beam units.

[0043] The elastic beam unit includes at least one elastic beam.

[0044] In a possible implementation, the elastic beam is an S-shaped beam.

[0045] In a possible implementation, the coupling beam is a straight beam.

[0046] In the embodiment, the elastic beam unit can have only one elastic beam, and the coupling beam unit 17 can have only one coupling beam. For example, Figure 3 the first elastic beam unit 13 can be an S-shaped elastic beam, and the coupling beam unit 17 can be a coupling beam formed by a straight beam, and the end point on one side of the S-shaped elastic beam is connected to the end point on one side of the straight beam. For example, Figure 4And Figure 6 The first elastic beam unit 13 can also be composed of a plurality of S-shaped elastic beams, and the coupling beam unit 17 can be a coupling beam composed of a plurality of straight beams, and the end point of one side of each S-shaped elastic beam is connected with the end point of one side of one straight beam. Figure 5 And Figure 7 The first elastic beam unit 13 can also be composed of a plurality of S-shaped elastic beams, and the coupling beam unit 17 can be a coupling beam composed of a plurality of straight beams, and the end point of one side of each S-shaped elastic beam is connected with the end point of one side of one straight beam. It should be pointed out that the specific connection relationship between the S-shaped elastic beam and the straight beam can be selected according to actual implementation needs. It should be noted that the second elastic beam unit 14, the third elastic beam unit 15, the fourth elastic beam unit 16 and the first elastic beam unit 13 are of the same structure, and the specific structure can be referred to the first elastic beam unit 13.

[0047] In a possible implementation, the detection capacitor structure 18 is composed of a plurality of detection capacitor units.

[0048] The detection capacitor unit includes a movable comb tooth 181 fixed to the movable mass 12 and a fixed comb tooth 182 anchored to the substrate layer 10.

[0049] In the embodiment, the detection capacitor unit can adopt a conventional structure. The movable comb tooth 181 is fixed to the movable mass 12, and the fixed comb tooth 182 is fixed to the substrate layer 10. The movable comb tooth 181 and the fixed comb tooth 182 in each detection capacitor unit are in a certain tooth engagement state. In a specific working state: when the movable mass 12 moves to the left in the X-axis direction, the relative distance between the movable comb tooth 181 and the fixed comb tooth 182 gradually increases, and the capacitance value of the detection capacitor unit gradually decreases; when the movable mass 12 moves to the right in the X-axis direction, the relative distance between the movable comb tooth 181 and the fixed comb tooth 182 gradually decreases, and the capacitance value of the detection capacitor unit gradually increases.

[0050] On the basis of the original S-shaped elastic beam design of the accelerometer, the coupling beam design is newly added. The S-shaped elastic beams located at the symmetric positions of the structure are connected through the coupling beam, so that the accelerometer has a larger sensitivity, and at the same time, the accelerometer has a better dynamic output characteristic, and the cross-axis sensitivity is reduced, and the overall anti-impact performance is improved.

[0051] The above embodiments should not limit the utility model in any way, and any technical solution obtained by equivalent replacement or equivalent conversion falls within the protection scope of the utility model.

Claims

1. A beam and anchor point accelerometer on the outside of a structure, characterized by, The device layer is located above the substrate layer; The substrate layer is located in XY plane, and the device layer is located above the substrate layer; The device layer comprises an anchor point, a movable mass, a first elastic beam unit, a second elastic beam unit, a third elastic beam unit, a fourth elastic beam unit, a coupling beam unit, a detection capacitance structure, and an outer frame; The outer frame is anchored at the edge of the substrate layer by four anchor points; The movable mass is located in the middle of the substrate layer, and is connected to the left side of the outer frame by the first elastic beam unit and the second elastic beam unit respectively, and is connected to the right side of the outer frame by the third elastic beam unit and the fourth elastic beam unit respectively; The first elastic beam unit and the third elastic beam unit are connected by a coupling beam unit parallel to the X-axis on the upper and lower sides of the movable mass respectively, and the second elastic beam unit and the fourth elastic beam unit are connected by a coupling beam unit parallel to the X-axis on the upper and lower sides of the movable mass respectively; The detection capacitance structure is anchored on the substrate layer in the middle region of the movable mass and is connected to the movable mass; When the movable mass moves along the X-axis direction, the capacitance value of the detection capacitance structure changes, thereby achieving detection of acceleration.

2. The accelerometer of claim 1, wherein The coupling beam unit comprises at least one coupling beam; The first elastic beam unit, the second elastic beam unit, the third elastic beam unit, and the fourth elastic beam unit are the same elastic beam unit; The elastic beam unit comprises at least one elastic beam.

3. The accelerometer of claim 2, wherein, The elastic beam is S-shaped.

4. The accelerometer of claim 2, wherein, The coupling beam is a straight beam.

5. The accelerometer of claim 1, wherein The detection capacitance structure comprises a plurality of detection capacitance units; The detection capacitance unit comprises a movable comb tooth fixed to the movable mass and a fixed comb tooth anchored to the substrate layer.

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