Accelerometer with beams and anchors inside structure

Abstract

The utility model provides an accelerometer with beams and anchor points on the inner side of a structure. The accelerometer comprises a substrate layer and a device layer. The plane where the substrate layer is located is an XY plane; the movable mass block is connected with the upper frame and the lower frame through a first elastic beam unit, a second elastic beam unit, a third elastic beam unit and a fourth elastic beam unit. The upper frame and the lower frame are connected with the substrate layer through the first anchor point and the second anchor point; the first elastic beam unit and the third elastic beam unit are connected through a first coupling beam unit parallel to the X axis, and the second elastic beam unit and the fourth elastic beam unit are connected through a second coupling beam unit parallel to the X axis. The detection capacitor structure is connected between the substrate layer and 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 in structure inside accelerometer. BACKGROUND

[0002] Capacitive accelerometer is based on Hooke's law, uses external acceleration to change the displacement of sensitive mass, and further transforms into the change of capacitance to measure. The common translational accelerometer beam structure is mainly S-shaped beam at present. In order to ensure the stability of accelerometer output and reduce cross-axis sensitivity, the working modal frequency and the parasitic modal frequency should be as far as possible in design, which requires that the number of turns and the length of S-shaped elastic beam should not be designed too long. This limitation greatly restricts the sensitivity of accelerometer. On the other hand, if the accelerometer sensitivity is ensured to be large, the parasitic modal frequency is close to the working modal frequency, the dynamic output stability of the whole accelerometer is poor, is easily affected by external environment, and has large cross-axis sensitivity.

[0003] Therefore, it is necessary to provide an accelerometer structure design technical scheme which can have good dynamic output stability under the condition of large accelerometer sensitivity. SUMMARY

[0004] To solve the above technical problems, the utility model provides a beam and anchor point in structure inside accelerometer.

[0005] The utility model provides a beam and anchor point in structure inside accelerometer, including substrate layer and device layer;

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

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

[0008] The movable mass is provided with symmetrical first notch and second notch on the upper and lower sides of the middle part;

[0009] The first elastic beam unit and the third elastic beam unit are sequentially arranged on the left side of the first notch and the right side of the first notch, and the movable mass is connected with the upper frame;

[0010] The second elastic beam unit and the fourth elastic beam unit are sequentially arranged on the left side of the second notch and the right side of the second notch, and the movable mass is connected with the lower frame;

[0011] The upper frame and the lower frame are connected with the substrate layer through the first anchor point and the second anchor point respectively;

[0012] The first elastic beam unit and the third elastic beam unit, and the second elastic beam unit and the fourth elastic beam unit are connected through the first coupling beam unit and the second coupling beam unit respectively, which are parallel to the X axis and located at the first notch and the second notch respectively;

[0013] The first coupling beam unit is located on the upper side of the first anchor point;

[0014] The second coupling beam unit is located on the lower side of the second anchor point;

[0015] The detection capacitance structure is anchored on the substrate layer and connected with the movable mass block in the window area distributed on the movable mass block;

[0016] When the movable mass block moves along the X axis direction, the capacitance value of the detection capacitance structure changes, so as to realize the detection of acceleration.

[0017] In a possible implementation, the first coupling beam unit and the second coupling beam unit are the same coupling beam unit;

[0018] The coupling beam unit at least comprises one coupling beam;

[0019] 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;

[0020] The elastic beam unit at least comprises one elastic beam.

[0021] In a possible implementation, the elastic beam is S-shaped.

[0022] In a possible implementation, the coupling beam is a straight beam.

[0023] In a possible implementation, the detection capacitance structure is composed of a plurality of detection capacitance units;

[0024] The detection capacitance unit comprises movable comb teeth fixed on the movable mass block and fixed comb teeth anchored on the substrate layer.

[0025] The technical scheme provided by the utility model has at least the following beneficial effects:

[0026] The first elastic beam unit is connected with the third elastic beam unit on the upside of the first anchor point through the first coupling beam unit parallel to the X axis and located at the first gap, and the second elastic beam unit is connected with the fourth elastic beam unit on the downside of the second anchor point through the second coupling beam unit parallel to the X axis and located at the second gap, so that the accelerometer has better dynamic output characteristics and the cross-axis sensitivity is reduced while the sensitivity of the accelerometer is improved. BRIEF DESCRIPTION OF DRAWINGS

[0027] Figure 1 A schematic diagram of the overall structure of the accelerometer with the beam and the anchor point on the inner side of the structure is provided for the embodiment of the utility model;

[0028] Figure 2 A schematic diagram of the structure of the detection capacitor unit is provided for the embodiment of the utility model;

[0029] Figure 3 A schematic diagram of the partial structure of the accelerometer with the beam and the anchor point on the inner side of the structure is provided for the embodiment of the utility model;

[0030] Figure 4 A schematic diagram of the connection structure between the substrate layer, the first anchor point and the upper frame is provided for the embodiment of the utility model;

[0031] Figure 5 A schematic diagram of the structure of the movable mass is provided for the embodiment of the utility model;

[0032] In the drawings, 10, substrate layer; 11, first anchor point; 12, second anchor point; 13, upper frame; 14, lower frame; 15, movable mass; 16, first elastic beam unit; 17, second elastic beam unit; 18, third elastic beam unit; 19, fourth elastic beam unit; 20, first coupling beam unit; 21, second coupling beam unit; 22, detection capacitor structure; 151, first gap; 152, second gap; 153, window area; 221, movable comb tooth; 222, fixed comb tooth. DETAILED DESCRIPTION

[0033] In order to deepen the understanding of the utility model, the utility model will be further described in detail in combination with the drawings and the embodiment below, and the embodiment is only used for explaining the utility model and does not constitute a limitation on the protection scope of the utility model.

[0034] Please refer to Figures 1 to 5 The utility model provides an accelerometer with the beam and the anchor point on the inner side of the structure, which comprises a substrate layer 10 and a device layer;

[0035] The plane where the substrate layer 10 is located is the XY plane, and the device layer is located above the substrate layer 10;

[0036] The device layer comprises a first anchor point 11, a second anchor point 12, an upper frame 13, a lower frame 14, a movable mass 15, a first elastic beam unit 16, a second elastic beam unit 17, a third elastic beam unit 18, a fourth elastic beam unit 19, a first coupling beam unit 20, a second coupling beam unit 21, and a detection capacitance structure 22;

[0037] The movable mass 15 is provided with a first notch 151 and a second notch 152 on the upper and lower sides of the middle part of the movable mass 15 in sequence;

[0038] The first elastic beam unit 16 and the third elastic beam unit 18 are connected to the upper frame 13 and the movable mass 15 on the left side of the first notch 151 and the right side of the first notch 151 in sequence;

[0039] The second elastic beam unit 17 and the fourth elastic beam unit 19 are connected to the lower frame 14 and the movable mass 15 on the left side of the second notch 152 and the right side of the second notch 152 in sequence;

[0040] The upper frame 13 and the lower frame 14 are connected to the substrate layer 10 through the first anchor point 11 and the second anchor point 12 respectively;

[0041] The first elastic beam unit 16 and the third elastic beam unit 18 are connected through the first coupling beam unit 20 and the second coupling beam unit 21 which are parallel to the X axis and located on the first notch 151 and the second notch 152 respectively;

[0042] The first coupling beam unit 20 is located on the upper side of the first anchor point 11;

[0043] The second coupling beam unit 21 is located on the lower side of the second anchor point 12;

[0044] The detection capacitance structure 22 is anchored on the substrate layer 10 and connected to the movable mass 15 in the window area 153 distributed on the movable mass 15;

[0045] When the movable mass 15 moves along the X axis direction, the capacitance value of the detection capacitance structure 22 changes, so as to realize the detection of acceleration.

[0046] In a specific embodiment, the substrate layer 10 can be rectangular. The first anchor point 11 and the second anchor point 12 are both conventional anchor points and can be designed as rectangles. The connection relationship between the first anchor point 11, the upper frame 13 and the substrate layer 10 can be referred to the connection relationship between the second anchor point 12, the lower frame 14 and the substrate layer 10. Figure 4The connection relationship between the second anchor point 12 and the lower frame 14 and the substrate layer 10 is similar to the above. The first elastic beam unit 16, the second elastic beam unit 17, the third elastic beam unit 18 and the fourth elastic beam unit 19 are the same elastic beam units. The first elastic beam unit 16 and the second elastic beam unit 17 are symmetrically distributed along the center line of the movable mass 15 in the X-axis direction. The third elastic beam unit 18 and the fourth elastic beam unit 19 are symmetrically distributed along the center line of the movable mass 15 in the Y-axis direction. The first coupling beam unit 20 and the second coupling beam unit 21 are the same coupling beam units. The first coupling beam unit 20 parallel to the X-axis connects the first elastic beam unit 16 and the third elastic beam unit 18. The second coupling beam unit 21 parallel to the X-axis connects the second elastic beam unit 17 and the fourth elastic beam unit 19. The elastic beam units on the left and right sides of the movable mass 15 are connected by the two coupling beam units. In this way, the accelerometer has a large sensitivity and a good dynamic output characteristic, and the cross-axis sensitivity is reduced and the overall anti-impact performance is improved. The window area 153 on the movable mass 15 is in communication with the bottom substrate layer 10, and the detection capacitor structure 22 is arranged in the window area 153. The detection capacitor structure 22 can adopt a comb structure, and one part of the structure is fixed on the movable mass 15 and the other part of the structure is anchored on the substrate layer 10. In the working state, when the accelerometer is subjected to an external force, the movable mass 15 moves left or right along the X-axis direction by inertia, and the capacitance value of the detection capacitor structure 22 changes, so that the acceleration detection can be realized.

[0047] In a possible implementation, the first coupling beam unit 20 and the second coupling beam unit 21 are the same coupling beam unit.

[0048] The coupling beam unit includes at least one coupling beam.

[0049] The first elastic beam unit 16, the second elastic beam unit 17, the third elastic beam unit 18 and the fourth elastic beam unit 19 are the same elastic beam units.

[0050] The elastic beam unit includes at least one elastic beam.

[0051] In a possible implementation, the elastic beam is an S-shaped beam.

[0052] In a possible implementation, the coupling beam is a straight beam.

[0053] In this embodiment, the elastic beam unit can have only one elastic beam, and the coupling beam unit can have only one coupling beam. For example,Figure 3 In one possible implementation, the first elastic beam unit 16 is composed of a plurality of S-shaped elastic beams, and the first coupling beam unit 20 is composed of a plurality of straight beam structure coupling beams. One side of an end point of each S-shaped elastic beam is connected to one side of an end point of a straight beam. The leftmost S-shaped elastic beam is connected to the movable mass 15, and one end of the rightmost S-shaped elastic beam is connected to the upper frame 13. The upper frame 13 is connected to the substrate layer 10 through the first anchor point 11. It should be noted that when the first elastic beam unit 16 is composed of a plurality of S-shaped elastic beams, the first coupling beam unit 20 can also be a straight beam structure coupling beam. One side of an end point of each S-shaped elastic beam is connected to one side of an end point of the straight beam. In another implementation, the first elastic beam unit 16 can be an S-shaped elastic beam, and the first coupling beam unit 20 can be a straight beam structure coupling beam. One side of an end point of the S-shaped elastic beam is connected to one side of an end point of the straight beam. It should be noted that the specific connection relationship between the S-shaped elastic beam and the straight beam can be selected according to actual implementation needs. The second elastic beam unit 17, the third elastic beam unit 18, and the fourth elastic beam unit 19 have the same structure as the first elastic beam unit 16. For details, refer to the first elastic beam unit 16.

[0054] In one possible implementation, the detection capacitor structure 22 is composed of a plurality of detection capacitor units.

[0055] The detection capacitor unit includes a movable comb tooth 221 fixed to the movable mass 15 and a fixed comb tooth 222 anchored to the substrate layer 10.

[0056] In this embodiment, the detection capacitor unit can adopt a conventional structure. The window area 153 on the movable mass 15 is divided into a plurality of window units, and each window unit is provided with a detection capacitor unit. The movable comb tooth 221 is fixed to the movable mass 15, and the fixed comb tooth 222 is fixed to the substrate layer 10. The movable comb tooth 221 and the fixed comb tooth 222 in each detection capacitor unit are in a certain tooth engagement state. In a specific working state: when the movable mass 15 moves to the left in the X-axis direction, the relative distance between the movable comb tooth 221 and the fixed comb tooth 222 gradually increases, and the capacitance value of the detection capacitor unit gradually decreases; when the movable mass 15 moves to the right in the X-axis direction, the relative distance between the movable comb tooth 221 and the fixed comb tooth 222 gradually decreases, and the capacitance value of the detection capacitor unit gradually increases.

[0057] On the basis of the original S-shaped elastic beam design of the accelerometer, the application adds a coupling beam design. The S-shaped elastic beams located at the symmetrical positions of the structure are connected through the coupling beam. In this way, the accelerometer can have a larger sensitivity while ensuring a better dynamic output characteristic, and the cross-axis sensitivity can be reduced and the overall anti-impact performance can be improved.

[0058] The above embodiments should not be in any way limit the utility model, all technical solutions obtained by equivalent replacement or equivalent conversion fall within the protection scope of the utility model.

Claims

1. A beam and anchor point accelerometer on the inside of a structure, characterized by, The device layer is located above the substrate layer; The substrate layer is located in an XY plane, and the device layer is located above the substrate layer; The device layer includes a first anchor point, a second anchor point, an upper frame, a lower frame, a movable mass, a first elastic beam unit, a second elastic beam unit, a third elastic beam unit, a fourth elastic beam unit, a first coupling beam unit, a second coupling beam unit, and a detection capacitor structure; The movable mass has a first notch and a second notch symmetrically formed on the upper and lower sides of the middle part of the movable mass; The first elastic beam unit and the third elastic beam unit are sequentially connected to the movable mass and the upper frame on the left side of the first notch and the right side of the first notch; The second elastic beam unit and the fourth elastic beam unit are sequentially connected to the movable mass and the lower frame on the left side of the second notch and the right side of the second notch; The upper frame and the lower frame are connected to the substrate layer through the first anchor point and the second anchor point, respectively; The first elastic beam unit and the third elastic beam unit are connected through the first coupling beam unit and the second coupling beam unit parallel to the X-axis located on the left side of the first notch and the right side of the second notch, respectively; The first coupling beam unit is located on the upper side of the first anchor point; The second coupling beam unit is located on the lower side of the second anchor point; The detection capacitor structure is anchored on the substrate layer and connected to the movable mass in the window area distributed on the movable mass; When the movable mass moves along the X-axis direction, the capacitance value of the detection capacitor structure changes, thereby achieving detection of acceleration.

2. The accelerometer of claim 1, wherein The first coupling beam unit and the second coupling beam unit are the same coupling beam unit; The coupling beam unit includes 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 includes 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 capacitor structure is composed of a plurality of detection capacitor units; The detection capacitor unit includes a movable comb tooth fixed to the movable mass and a fixed comb tooth anchored to the substrate layer.

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