Graphene piezoresistive accelerometer

Abstract

The invention discloses a graphene piezoresistive accelerometer, which relates to the technical field of sensor measurement, and comprises a support frame, a central island, a plurality of metal electrodes, a plurality of groups of connecting beams, a plurality of graphene films and a plurality of mass blocks, each inner side wall of the supporting frame is connected with the outer wall of the center island through a set of connecting beams, each connecting beam comprises a sensitive beam and a plurality of supporting beams, and the mass blocks are installed on the back side of the center island, the back side of each sensitive beam and the back side of each supporting beam. All the metal electrodes and all the graphene films are installed on the front end face of the supporting frame, every two metal electrodes are connected with one graphene film, the first end of the sensitive beam is connected with the supporting frame, the graphene films are arranged corresponding to the first end of the sensitive beam, and the thickness of the first end of the sensitive beam is smaller than that of other positions of the sensitive beam. According to the invention, the sensitivity is good, the influence of the inherent frequency on the sensitivity is small, and a high G value can be realized.

Description

Technical Field

[0001] The present invention relates to the field of sensor measurement technology, and in particular to a graphene piezoresistive accelerometer. Background Art

[0002] MEMS (micro-electromechanical systems) piezoresistive accelerometers, using piezoresistors as their core sensitive components, are widely used in specialized applications such as weapon penetration, explosive shock, aerospace satellites, and inertial navigation systems. With numerous advantages, including small size, low power consumption, ease of integration, and low cost, they have become a key component in impact dynamics detection technology.

[0003] However, low-G accelerometers cannot meet the needs of the above applications, so the research on high-G accelerometers has important application value; due to structural limitations, there is a mutually restrictive relationship between the sensitivity and natural frequency of traditional high-G graphene piezoresistive accelerometers, and it is difficult to ensure high sensitivity and high natural frequency at the same time. This has greatly hindered the further development and widespread application of MEMS graphene piezoresistive accelerometers. How to break through this bottleneck has become a difficult problem that needs to be overcome urgently in this field. Summary of the Invention

[0004] The purpose of the present invention is to provide a graphene piezoresistive accelerometer to solve the problems existing in the above-mentioned prior art, with good sensitivity, less influence of natural frequency on sensitivity, and the ability to achieve high G value.

[0005] To achieve the above object, the present invention provides the following solutions:

[0006] The present invention provides a graphene piezoresistive accelerometer, comprising a supporting frame, a central island, multiple metal electrodes, multiple groups of connecting beams, multiple graphene membranes and multiple mass blocks, wherein the central island is located in the middle of the supporting frame, and each inner side wall of the supporting frame is connected to the outer wall of the central island by a group of connecting beams, the connecting beams include a sensitive beam and several supporting beams, the mass blocks are installed on the back side of the central island, the back side of each sensitive beam and the back side of each supporting beam, each metal electrode and each graphene membrane is installed on the front end face of the supporting frame, and every two metal electrodes are connected to one graphene membrane, the first end of the sensitive beam is connected to the supporting frame, and the graphene membrane is arranged corresponding to the first end of the sensitive beam, and the thickness of the first end of the sensitive beam is less than the thickness of the rest of the sensitive beam.

[0007] Preferably, the support frame is a square frame, and the connecting beams are in four groups, and the four groups of connecting beams are respectively arranged corresponding to the four sides of the support frame.

[0008] Preferably, in each group of the connecting beams, there are two supporting beams, and the two supporting beams are respectively located on both sides of the sensitive beam.

[0009] Preferably, the support beams on the support frame are sequentially the first support beam, the second support beam, the third support beam, the fourth support beam, the fifth support beam, the sixth support beam, the seventh support beam and the eighth support beam, and the sensitive beams on the support frame are sequentially the first sensitive beam, the second sensitive beam, the third sensitive beam and the fourth sensitive beam, the first sensitive beam is located between the first support beam and the second support beam, the second sensitive beam is located between the third support beam and the fourth support beam, the third sensitive beam is located between the fifth support beam and the sixth support beam, and the fourth sensitive beam is located between the seventh support beam and the eighth support beam.

[0010] Preferably, there are eight metal electrodes, and the eight metal electrodes are sequentially the first metal electrode, the second metal electrode, the third metal electrode, the fourth metal electrode, the fifth metal electrode, the sixth metal electrode, the seventh metal electrode and the eighth metal electrode; there are four graphene films, and the four graphene films are sequentially the first graphene film, the second graphene film, the third graphene film and the fourth graphene film; the first graphene film is connected between the first metal electrode and the second metal electrode, and the first graphene film is arranged corresponding to the first sensitive beam; the second graphene film is connected between the third metal electrode and the fourth metal electrode, and the second graphene film is arranged corresponding to the second sensitive beam; the third graphene film is connected between the fifth metal electrode and the sixth metal electrode, and the third graphene film is arranged corresponding to the third sensitive beam; the fourth graphene film is connected between the seventh metal electrode and the eighth metal electrode, and the fourth graphene film is arranged corresponding to the fourth sensitive beam.

[0011] Preferably, the upper surface of the first graphene film is covered with a first protective film, the upper surface of the second graphene film is covered with a second protective film, the upper surface of the third graphene film is covered with a third protective film, and the upper surface of the fourth graphene film is covered with a fourth protective film.

[0012] Preferably, the mass blocks are divided into a main mass block, a sensitive beam supporting mass block and a supporting beam supporting mass block, the main mass block is located on the back side of the central island, each of the sensitive beam supporting mass blocks is located on the back side of each of the sensitive beams, and each of the supporting beam supporting mass blocks is located on the back side of each of the supporting beams, and the sensitive beam supporting mass blocks on the back sides of the first sensitive beam, the second sensitive beam, the third sensitive beam and the fourth sensitive beam are respectively the first sensitive beam supporting mass block, the second sensitive beam supporting mass block, the third sensitive beam supporting mass block and the fourth sensitive beam supporting mass block, and the supporting beam supporting mass blocks on the back sides of the first supporting beam, the second supporting beam, the third supporting beam, the fourth supporting beam, the fifth supporting beam, the sixth supporting beam, the seventh supporting beam and the eighth supporting beam are respectively the first supporting beam supporting mass block, the second supporting beam supporting mass block, the third supporting beam supporting mass block, the fourth supporting beam supporting mass block, the fifth supporting beam supporting mass block, the sixth supporting beam supporting mass block, the seventh supporting beam supporting mass block and the eighth supporting beam supporting mass block.

[0013] Preferably, the cross-sectional area of ​​the main mass block is equal to the cross-sectional area of ​​the central island, the width of each sensitive beam supporting mass block is respectively equal to the width of each sensitive beam, the width of each supporting beam supporting mass block is respectively equal to the width of each supporting beam, and the thickness of the main mass block, the thickness of each sensitive beam supporting mass block and the thickness of each supporting beam supporting mass block are all equal, and the main mass block, each sensitive beam supporting mass block and each supporting beam supporting mass block do not protrude from the back side of the supporting frame.

[0014] Preferably, the thickness of the first end of the sensitive beam is 1 / 2 of the thickness of the remaining positions of the sensitive beam.

[0015] Preferably, the central island is square, circular, octagonal or diamond-shaped.

[0016] Compared with the prior art, the present invention has achieved the following technical effects:

[0017] The graphene piezoresistive accelerometer provided by the present invention includes a support frame, a central island, multiple metal electrodes, multiple groups of connecting beams, multiple graphene membranes and multiple mass blocks. The central island is a large-area thin plate, which is located in the middle of the support frame. The inner side walls of the support frame are connected to the outer wall of the central island by a group of connecting beams. The connecting beams include a sensitive beam and multiple supporting beams, which separate the supporting beam and the sensitive beam, thereby alleviating the mutual constraint relationship between the natural frequency and sensitivity of the traditional accelerometer to a certain extent. The mass blocks are installed on the back side of the central island, the back side of each sensitive beam and the back side of each supporting beam, thereby forming a composite structure of multiple beams-mass blocks-central island. At the same time, the mass blocks increase the mass and strength of the sensitive beams and the supporting beams, improve the stability and bending stiffness of the overall structure, and thus improve the natural frequency of the graphene piezoresistive accelerometer. Each metal electrode and each graphene membrane is installed on the front end face of the support frame, and every two metal electrodes are connected to a graphene membrane. The graphene membrane is a thin film structure. By arranging the graphene membrane on the sensitive beam to form a piezoresistor, stress changes in different directions can be detected, and then accelerations in different directions can be detected. The first end of the sensitive beam is connected to the support frame, and the graphene membrane is arranged corresponding to the first end of the sensitive beam. The thickness of the first end of the sensitive beam is less than the thickness of the rest of the sensitive beam, thereby increasing the stress and strain at the root of the sensitive beam. When subjected to high-G acceleration in any direction, the central island, each group of connecting beams and the mass block all move in the direction of acceleration. At this time, the bending deformation of the sensitive beam becomes larger, thereby improving the sensitivity. Through the above design, the present invention has the advantages of high integration, high sensitivity and strong overload resistance, and alleviates the restrictive relationship between sensitivity and natural frequency. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0019] Figure 1 Schematic diagram of the structure of the graphene piezoresistive accelerometer in Example 1 (to show the front structure);

[0020] Figure 2 Schematic diagram of the structure of the graphene piezoresistive accelerometer in Example 1 (to show the mass blocks on the back);

[0021] Figure 3 for Figure 1 Main view of the graphene piezoresistive accelerometer;

[0022] Figure 4Schematic diagram of the structure of the graphene piezoresistive accelerometer in Example 1 when all mass blocks are omitted;

[0023] Figure 5 for Figure 4 Schematic diagram of the structure of the graphene piezoresistive accelerometer when the main mass block is added;

[0024] Figure 6 for Figure 5 Schematic diagram of the structure of the graphene piezoresistive accelerometer when adding various mass blocks;

[0025] Figure 7 This is a cross-sectional view of the sensitive beam in Example 1 (before the first end of the sensitive beam is thinned);

[0026] Figure 8 This is a cross-sectional view of the sensitive beam in Example 1 (after the first end of the sensitive beam is thinned);

[0027] Figure 9 for Figure 8 An enlarged schematic diagram of the structure at the first end of the medium sensitive beam;

[0028] Figure 10 Schematic diagram of the structure of the graphene film in Example 1;

[0029] Figure 11 Schematic diagram of the placement of the graphene film in Example 1;

[0030] Figure 12 Schematic diagram of the connection between the metal electrode and the graphene film in Example 1;

[0031] Figure 13 Schematic diagram of a quarter Wheatstone bridge formed by the graphene piezoresistive accelerometer in Example 1;

[0032] Figure 14 This is a front view of the graphene piezoresistive accelerometer in Example 2;

[0033] Figure 15 This is a front view of the graphene piezoresistive accelerometer in Example 3;

[0034] Figure 16 This is a front view of the graphene piezoresistive accelerometer in Example 4;

[0035] In the figure: 1. Graphene piezoresistive accelerometer; 1-1. Support frame; 2. Central square island, 2-1. Central circular island, 2-2. Central octagonal island, 2-3. Central rhombus island; 3-1. First metal electrode, 3-2. Second metal electrode, 3-3. Third metal electrode, 3-4. Fourth metal electrode, 3-5. Fifth metal electrode, 3-6. Sixth metal electrode, 3-7. Seventh metal electrode, 3-8. Eighth metal electrode; 4-1. First sensitive beam, 4-2. Second sensitive beam, 4-3. Third sensitive beam, 4-4. Fourth sensitive beam; 5-1. First support beam, 5-2. Second support beam, 5-3. Third support beam, 5-4. Fourth support beam, 5-5. Fifth support beam, 5-6. Sixth support beam, 5-7. Seventh support beam, 5-8. Eighth support beam; 6-1, first graphene film, 6-2, second graphene film, 6-3, third graphene film, 6-4, fourth graphene film; 7-1, first protective film, 7-2, second protective film, 7-3, third protective film, 7-4, fourth protective film; 8, main mass block; 9-1, first sensitive beam supporting mass block, 9-2, second sensitive beam supporting mass block, 9-3, third sensitive beam supporting mass block, 9-4, fourth sensitive beam supporting mass block; 10-1, first supporting beam supporting mass block, 10-2, second supporting beam supporting mass block, 10-3, third supporting beam supporting mass block, 10-4, fourth supporting beam supporting mass block, 10-5, fifth supporting beam supporting mass block, 10-6, sixth supporting beam supporting mass block, 10-7, seventh supporting beam supporting mass block, 10-8, eighth supporting beam supporting mass block. DETAILED DESCRIPTION

[0036] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0037] The purpose of the present invention is to provide a graphene piezoresistive accelerometer to solve the problems existing in the prior art, with good sensitivity, little influence of natural frequency on sensitivity, and the ability to achieve high G value.

[0038] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the present invention is further described in detail below with reference to the accompanying drawings and specific embodiments.

[0039] Example 1

[0040] like Figures 1-13As shown, this embodiment provides a graphene piezoresistive accelerometer 1, including a support frame 1-1, a central island, multiple metal electrodes, multiple groups of connecting beams, multiple graphene membranes and multiple mass blocks. The central island is a large-area thin plate, and the central island is located in the middle of the support frame 1-1. The inner walls of the support frame 1-1 and the outer walls of the central island are connected by a group of connecting beams respectively. The connecting beams include a sensitive beam and several supporting beams, which separate the supporting beam and the sensitive beam, and to a certain extent alleviate the mutual constraint relationship between the natural frequency and sensitivity of the traditional accelerometer. The mass blocks are installed on the back side of the central island, the back side of each sensitive beam and the back side of each supporting beam, thereby forming a composite structure of multiple beams-mass blocks-central island. At the same time, the mass blocks increase the mass and strength of the sensitive beams and the supporting beams, improve the stability and bending stiffness of the overall structure, and thus improve the graphene piezoresistive accelerometer 1. Natural frequency, each metal electrode and each graphene membrane are installed on the front end face of the support frame 1-1, and every two metal electrodes are connected to a graphene membrane. The graphene membrane is a thin film structure. By arranging the graphene membrane on the sensitive beam to form a piezoresistor, it is possible to detect stress changes in different directions, and thus detect accelerations in different directions. The first end of the sensitive beam is connected to the support frame 1-1, and the graphene membrane is arranged corresponding to the first end of the sensitive beam. The thickness of the first end of the sensitive beam is less than the thickness of the rest of the sensitive beam, thereby increasing the stress and strain at the root of the sensitive beam. When subjected to high G-value acceleration in any direction, the central island, each group of connecting beams and the mass block all move in the direction of acceleration. At this time, the bending deformation of the sensitive beam becomes larger, thereby improving the sensitivity. Through the above design, this embodiment has the advantages of high integration, high sensitivity and strong overload resistance, and alleviates the restrictive relationship between sensitivity and natural frequency.

[0041] Specifically, the support frame 1-1 is a square frame, and there are four groups of connecting beams. The four groups of connecting beams are respectively arranged corresponding to the four sides of the support frame 1-1 to achieve a stable connection between the support frame 1-1 and the center island. In actual application, technical personnel in this field can select the specific shape of the support frame 1-1 according to actual needs.

[0042] In each group of connecting beams, there are two supporting beams, and the two supporting beams are respectively located on both sides of the sensitive beam, which can play a stable supporting role and improve the stability and overload resistance of the graphene piezoresistive accelerometer 1 in this embodiment.

[0043] The support beams on the support frame 1-1 are, in order, the first support beam 5-1, the second support beam 5-2, the third support beam 5-3, the fourth support beam 5-4, the fifth support beam 5-5, the sixth support beam 5-6, the seventh support beam 5-7, and the eighth support beam 5-8. The sensitive beams on the support frame 1-1 are, in order, the first sensitive beam 4-1, the second sensitive beam 4-2, the third sensitive beam 4-3, and the fourth sensitive beam 4-4. The first sensitive beam 4-1 is located between the first support beam 5-1 and the second support beam 5-2, the second sensitive beam 4-2 is located between the third support beam 5-3 and the fourth support beam 5-4, the third sensitive beam 4-3 is located between the fifth support beam 5-5 and the sixth support beam 5-6, and the fourth sensitive beam 4-4 is located between the seventh support beam 5-7 and the eighth support beam 5-8. In this embodiment, the thickness of the central island, the thickness of each sensitive beam, and the thickness of each support beam are all equal, and the dimensions of each sensitive beam and each support beam are all equal.

[0044] There are eight metal electrodes, and the eight metal electrodes are sequentially a first metal electrode 3-1, a second metal electrode 3-2, a third metal electrode 3-3, a fourth metal electrode 3-4, a fifth metal electrode 3-5, a sixth metal electrode 3-6, a seventh metal electrode 3-7 and an eighth metal electrode 3-8. There are four graphene films, and the four graphene films are sequentially a first graphene film 6-1, a second graphene film 6-2, a third graphene film 6-3 and a fourth graphene film 6-4. The first graphene film 6-1 is connected between the first metal electrode 3-1 and the second metal electrode 3-2, and the first graphene film 6-3 is connected between the first metal electrode 3-1 and the second metal electrode 3-2. A graphene film 6-1 is provided corresponding to the first sensitive beam 4-1. A second graphene film 6-2 is connected between the third metal electrode 3-3 and the fourth metal electrode 3-4, and the second graphene film 6-2 is provided corresponding to the second sensitive beam 4-2. A third graphene film 6-3 is connected between the fifth metal electrode 3-5 and the sixth metal electrode 3-6, and the third graphene film 6-3 is provided corresponding to the third sensitive beam 4-3. A fourth graphene film 6-4 is connected between the seventh metal electrode 3-7 and the eighth metal electrode 3-8, and the fourth graphene film 6-4 is provided corresponding to the fourth sensitive beam 4-4. As a preferred embodiment of this embodiment, the metal electrodes are elongated strips, connecting the graphene films to external resistors, thereby forming a quarter Wheatstone bridge circuit to convert resistance changes into voltage outputs. This differential electrical signal can reflect acceleration.

[0045] In this embodiment, the material of the metal electrode includes but is not limited to gold, platinum, etc.

[0046] The upper surface of the first graphene film 6-1 is covered with a first protective film 7-1, the upper surface of the second graphene film 6-2 is covered with a second protective film 7-2, the upper surface of the third graphene film 6-3 is covered with a third protective film 7-3, and the upper surface of the fourth graphene film 6-4 is covered with a fourth protective film 7-4. As a preferred embodiment of this embodiment, the graphene film is a U-shaped film, with the U-shaped opening of the graphene film facing away from the central island, and the back of the graphene film is parallel to the side wall of the support frame 1-1, thereby increasing the area of ​​the graphene film that is sensitive to stress and strain. Each protective film is a rectangular film, and the materials of the protective films include but are not limited to boron nitride, silicon dioxide, etc. The protective films completely wrap each graphene film, so that the graphene film is subjected to uniform stress, reducing the risk of physical damage to the graphene film, while also preventing the impact of external contamination and ambient temperature on the graphene. When designing the shape of the graphene film, those skilled in the art may also choose a serpentine film, etc.

[0047] In this embodiment, if Figure 13 As shown in the figure, R1 is a graphene film. Each graphene film can be connected to an external resistor to form a quarter Wheatstone bridge. When subjected to acceleration, the resistance value of the graphene film changes, which can greatly improve the sensitivity and accuracy of the test.

[0048] The mass blocks are divided into a main mass block 8, a sensitive beam support mass block and a support beam support mass block. The main mass block 8 is located on the back side of the central island, each sensitive beam support mass block is located on the back side of each sensitive beam, each support beam support mass block is located on the back side of each support beam, and the sensitive beam support mass blocks on the back side of the first sensitive beam 4-1, the second sensitive beam 4-2, the third sensitive beam 4-3 and the fourth sensitive beam 4-4 are the first sensitive beam support mass block 9-1, the second sensitive beam support mass block 9-2, the third sensitive beam support mass block 9-3 and the fourth sensitive beam support mass block 9-4 respectively, the first support beam 5-1, The support beam supporting mass blocks on the back side of the second support beam 5-2, the third support beam 5-3, the fourth support beam 5-4, the fifth support beam 5-5, the sixth support beam 5-6, the seventh support beam 5-7 and the eighth support beam 5-8 are respectively the first support beam supporting mass block 10-1, the second support beam supporting mass block 10-2, the third support beam supporting mass block 10-3, the fourth support beam supporting mass block 10-4, the fifth support beam supporting mass block 10-5, the sixth support beam supporting mass block 10-6, the seventh support beam supporting mass block 10-7 and the eighth support beam supporting mass block 10-8.

[0049] The cross-sectional area of ​​the main mass block 8 is equal to the cross-sectional area of ​​the central island, the width of each sensitive beam support mass block is respectively equal to the width of each sensitive beam, the width of each supporting beam support mass block is respectively equal to the width of each supporting beam, and there is a gap between each sensitive beam support mass block and the inner wall of the supporting frame 1-1, as well as between each sensitive beam support mass block and the outer wall of the central island, and there is a gap between each supporting beam support mass block and the inner wall of the supporting frame 1-1, as well as between each supporting beam support mass block and the outer wall of the central island, thereby effectively increasing the sensitivity, the thickness of the main mass block 8, the thickness of each sensitive beam support mass block and the thickness of each supporting beam support mass block are all equal, the main mass block 8, each sensitive beam support mass block and each supporting beam support mass block do not protrude from the back side of the supporting frame 1-1, and through the position setting of the main mass block 8, each sensitive beam support mass block and each supporting beam support mass block, the stability of the overall structure can be improved, and thus it can withstand a higher gravitational acceleration G value and has good overload resistance.

[0050] The thickness of the first end of the sensitive beam is 1 / 2 of the thickness of the remaining positions of the sensitive beam, and the first end of the sensitive beam is thinned to achieve a thickness different from that of the remaining positions of the sensitive beam.

[0051] The center island is the center square island 2, which has a square cross section and is easy to process, with smaller deflection and greater stress. Both ends of the supporting beam and the sensitive beam are chamfered.

[0052] In this embodiment, the materials used for the support frame 1 - 1 , the central island, the sensitive beams, the support beams, and the mass blocks include but are not limited to silicon, silicon oxide, and the like.

[0053] The specific application process of this embodiment is as follows:

[0054] When the graphene piezoresistive accelerometer 1 in this embodiment is subjected to acceleration in the Z-axis direction, the main mass block 8 of the central island will move up and down along the Z-axis, causing each sensitive beam, each supporting beam, each sensitive beam supporting mass block and each supporting beam supporting mass block to produce a large deformation, thereby causing large stress and strain at the root of each beam, changing the resistance of the graphene film, and thus measuring the acceleration of the Z-axis.

[0055] Example 2

[0056] like Figure 14 As shown, the difference between this embodiment and embodiment one is that the central island is a central circular island 2-1 with a circular cross-section, and the area of ​​the central circular island 2-1 is smaller than the area of ​​the central square island 2 in embodiment one, thereby increasing the natural frequency of the overall structure. At the same time, both ends of the supporting beam and both ends of the sensitive beam do not need to be chamfered.

[0057] Example 3

[0058] like Figure 15As shown, the difference between this embodiment and the first embodiment is that the central island is a central octagonal island 2-2 with an octagonal cross section.

[0059] Example 4

[0060] like Figure 16 As shown, the difference between this embodiment and embodiment 1 is that the central island is a central rhombus island 2-3 with a rhombus cross-section, and each sensitive beam and each supporting beam in this embodiment are connected to the four corners of the supporting frame 1-1. This structure increases the beam length and effectively improves the sensitivity of the overall structure.

[0061] However, the specific shape of the central island is not limited to the above embodiments, and those skilled in the art can also select any other symmetrical shape according to actual needs.

[0062] The present invention uses specific examples to illustrate the principles and implementation methods of the present invention. The above examples are only intended to help understand the method and core concept of the present invention. At the same time, those skilled in the art will find that the specific implementation methods and application scopes may vary based on the concept of the present invention. In summary, the contents of this specification should not be construed as limiting the present invention.

Claims

1. A graphene piezoresistive accelerometer, characterized in that: It includes a supporting frame, a central island, multiple metal electrodes, multiple groups of connecting beams, multiple graphene membranes and multiple mass blocks. The central island is located in the middle of the supporting frame, and each inner wall of the supporting frame is connected to the outer wall of the central island by a group of connecting beams. The connecting beams include a sensitive beam and several supporting beams. The mass blocks are installed on the back side of the central island, the back side of each sensitive beam and the back side of each supporting beam. Each metal electrode and each graphene membrane is installed on the front end face of the supporting frame, and every two metal electrodes are connected to one graphene membrane. The first end of the sensitive beam is connected to the supporting frame, and the graphene membrane is arranged corresponding to the first end of the sensitive beam. The thickness of the first end of the sensitive beam is less than the thickness of the rest of the sensitive beam.

2. The graphene piezoresistive accelerometer according to claim 1, wherein: The support frame is a square frame, and the connecting beams are in four groups, and the four groups of connecting beams are respectively arranged corresponding to the four sides of the support frame.

3. The graphene piezoresistive accelerometer according to claim 2, wherein: In each group of the connecting beams, there are two supporting beams, and the two supporting beams are respectively located on both sides of the sensitive beam.

4. The graphene piezoresistive accelerometer according to claim 3, characterized in that: The support beams on the support frame are sequentially the first support beam, the second support beam, the third support beam, the fourth support beam, the fifth support beam, the sixth support beam, the seventh support beam and the eighth support beam, and the sensitive beams on the support frame are sequentially the first sensitive beam, the second sensitive beam, the third sensitive beam and the fourth sensitive beam, the first sensitive beam is located between the first support beam and the second support beam, the second sensitive beam is located between the third support beam and the fourth support beam, the third sensitive beam is located between the fifth support beam and the sixth support beam, and the fourth sensitive beam is located between the seventh support beam and the eighth support beam.

5. The graphene piezoresistive accelerometer according to claim 4, characterized in that: There are eight metal electrodes, and the eight metal electrodes are the first metal electrode, the second metal electrode, the third metal electrode, the fourth metal electrode, the fifth metal electrode, the sixth metal electrode, the seventh metal electrode and the eighth metal electrode in sequence. There are four graphene films, and the four graphene films are the first graphene film, the second graphene film, the third graphene film and the fourth graphene film in sequence. The first graphene film is connected between the first metal electrode and the second metal electrode, and the first graphene film is arranged corresponding to the first sensitive beam. The second graphene film is connected between the third metal electrode and the fourth metal electrode, and the second graphene film is arranged corresponding to the second sensitive beam. The third graphene film is connected between the fifth metal electrode and the sixth metal electrode, and the third graphene film is arranged corresponding to the third sensitive beam. The fourth graphene film is connected between the seventh metal electrode and the eighth metal electrode, and the fourth graphene film is arranged corresponding to the fourth sensitive beam.

6. The graphene piezoresistive accelerometer according to claim 5, characterized in that: The upper surface of the first graphene film is covered with a first protective film, the upper surface of the second graphene film is covered with a second protective film, the upper surface of the third graphene film is covered with a third protective film, and the upper surface of the fourth graphene film is covered with a fourth protective film.

7. The graphene piezoresistive accelerometer according to claim 4, characterized in that: The mass blocks are divided into a main mass block, a sensitive beam supporting mass block and a supporting beam supporting mass block. The main mass block is located on the back side of the central island, each sensitive beam supporting mass block is located on the back side of each sensitive beam, and each supporting beam supporting mass block is located on the back side of each supporting beam. The sensitive beam supporting mass blocks on the back sides of the first sensitive beam, the second sensitive beam, the third sensitive beam and the fourth sensitive beam are respectively the first sensitive beam supporting mass block, the second sensitive beam supporting mass block, the third sensitive beam supporting mass block and the fourth sensitive beam supporting mass block. The supporting beam supporting mass blocks on the back sides of the first supporting beam, the second supporting beam, the third supporting beam, the fourth supporting beam, the fifth supporting beam, the sixth supporting beam, the seventh supporting beam and the eighth supporting beam are respectively the first supporting beam supporting mass block, the second supporting beam supporting mass block, the third supporting beam supporting mass block, the fourth supporting beam supporting mass block, the fifth supporting beam supporting mass block, the sixth supporting beam supporting mass block, the seventh supporting beam supporting mass block and the eighth supporting beam supporting mass block.

8. The graphene piezoresistive accelerometer according to claim 7, characterized in that: The cross-sectional area of ​​the main mass block is equal to the cross-sectional area of ​​the central island, the width of each sensitive beam supporting mass block is respectively equal to the width of each sensitive beam, the width of each support beam supporting mass block is respectively equal to the width of each support beam, and the thickness of the main mass block, the thickness of each sensitive beam supporting mass block and the thickness of each support beam supporting mass block are all equal, and the main mass block, each sensitive beam supporting mass block and each support beam supporting mass block do not protrude from the back side of the support frame.

9. The graphene piezoresistive accelerometer according to claim 1, characterized in that: The thickness of the first end of the sensitive beam is 1 / 2 of the thickness of the remaining positions of the sensitive beam.

10. The graphene piezoresistive accelerometer according to claim 1, characterized in that: The central island is square, circular, octagonal or rhombus-shaped.

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