A three-dimensional pressure sensor and a preparation method thereof

Abstract

The present invention relates to the technical field of pressure sensors, and discloses a three-dimensional pressure sensor and a method for preparing the same. The sensor comprises a bottom layer and a top layer arranged parallel to the bottom layer, wherein a trigger and a forward graphene detector are sequentially connected from the top layer to the bottom layer, the bottom layer is connected to a flexible support portion whose height is lower than the top layer, a mounting groove is formed in the middle of the flexible support portion, the forward graphene detector is located in the mounting groove, and at least four circumferential graphene detectors are connected between the forward graphene detector and the flexible support portion; a guide connector is connected between the top layer and the flexible support portion for allowing the top layer to move in a plane perpendicular to the flexible support portion. The present invention utilizes a forward graphene detector and a circumferential graphene detector to detect the three-dimensional pressure exerted on the top layer, and utilizes a guide connector to provide guidance for the top layer, thereby solving the problem of large detection errors in three-dimensional pressure sensors in the prior art.

Description

Technical Field

[0001] The present invention relates to the technical field of pressure sensors, and in particular to a three-dimensional pressure sensor and a preparation method thereof. Background Art

[0002] Pressure sensors primarily include transistor sensors, capacitive sensors, piezoelectric sensors, and piezoresistive sensors. Piezoresistive sensors convert mechanical pressure signals into resistance change signals. They are widely used due to their simple preparation process, low energy consumption, ease of signal collection, high sensitivity, and rapid response. Furthermore, as people's demands for exercise and health continue to increase, research on piezoresistive flexible electronic sensors has become a hot topic. Graphene, with its excellent conductivity, flexibility, mechanical properties, and stability, has become an ideal functional material for the preparation of flexible electronic sensors. Most graphene-based piezoresistive sensors utilize a surface conductive coating on a microstructured polymer substrate to achieve changes in the conductive path under varying pressures, thereby outputting electrical signals.

[0003] At present, in actual application, when a pressure sensor is subjected to external pressure, it will not only be subjected to Z-direction pressure perpendicular to the direction of the pressure sensor, but also to shear force along the X and Y directions. Existing pressure sensors can only detect Z-direction pressure, but cannot accurately measure the pressure with X and Y-direction shear force, resulting in large sensor errors and poor stability. Summary of the Invention

[0004] The present invention aims to provide a three-dimensional pressure sensor and a preparation method thereof, so as to solve the problem of large detection error of the three-dimensional pressure sensor in the prior art.

[0005] To solve the above problems, the present invention adopts the following technical solution: a three-dimensional pressure sensor, comprising a bottom layer and a top layer arranged parallel to the bottom layer, a trigger and a positive graphene detector being connected in sequence from the top layer to the bottom layer, a flexible support portion being connected to the bottom layer whose height is lower than the top layer, an installation groove being opened in the middle of the flexible support portion, the positive graphene detector being located in the installation groove, and at least four circumferential graphene detectors being connected between the positive graphene detector and the flexible support portion; a guide connecting member being connected between the top layer and the flexible support portion for the top layer to move in a plane perpendicular to the flexible support portion.

[0006] The principle of this solution is as follows: the graphene detector is used to detect the magnitude of the forward and circumferential pressures, and the trigger is connected to the top layer. When the top layer is subjected to an external force, the force received is transmitted to the forward graphene detector and the circumferential graphene detector through the trigger, thereby making a more accurate detection of the three-dimensional force; at the same time, in this application, a guide connector is connected between the top layer and the flexible support portion, and the guide connector is used to provide guidance for the top layer, so that the top layer can move in a plane perpendicular to the flexible support portion, so that when the top layer is subjected to a shear force in the X or Y direction, the top layer can drive the trigger to move toward the circumferential graphene detector and accurately detect the magnitude of the pressure in the X or Y direction.

[0007] The beneficial effects of this program are:

[0008] 1. More accurate pressure detection: Compared with the problem of large errors in the existing technology that it is impossible to detect shear forces in the X and / or Y directions, in this application, a forward graphene detector and several circumferential graphene detectors are provided, and the forward graphene detector is used to accurately detect the pressure in the Z direction. When the top layer is subjected to lateral shear force, not only the forward graphene detector can be used to detect the pressure in the Z direction, but also the circumferential graphene detector can be used to detect the shear forces in the X and Y directions, thereby achieving more comprehensive and accurate detection.

[0009] 2. Smaller detection error: In the present application, due to the provision of a guide connector, when the top layer is subjected to a lateral shear force, the top layer can move laterally more smoothly under the guiding force of the guide connector and squeeze the circumferential graphene detector, thereby more accurately detecting the lateral shear force (i.e., X-direction or Y-direction) applied to the top layer and reducing the detection error.

[0010] 3. Better stability: In this application, due to the provision of a guide connector, when the top layer is subjected to three-dimensional pressure and drives the trigger to displace, the guide connector can provide guidance for the top layer, so that the top layer can move more smoothly and has good stability in use.

[0011] Preferably, as an improvement, the guide connecting member includes a first connecting portion and a second connecting portion arranged perpendicular to each other, the first connecting portion is connected to the top layer and the first connecting portion is slidably connected to the second connecting portion, the second connecting portion is slidably connected to the flexible support portion, and the relative sliding direction of the first connecting portion and the second connecting portion is perpendicular to the relative sliding direction of the second connecting portion and the flexible support portion.

[0012] In this solution, the relative sliding of the first connecting part and the second connecting part, and the sliding connection of the second connecting part to the flexible support part are utilized, so that when the top layer is subjected to lateral shear force, it can easily slide under the guidance of the first connecting part and the second connecting part, thereby allowing the top layer to push the trigger to move toward the corresponding circumferential graphene detector to achieve accurate detection.

[0013] Preferably, as an improvement, the first connecting part includes a guide column connected to the bottom of the bottom layer, the second connecting part includes a second guide column and the second guide column is provided with a first guide hole that slides with the first guide column; the flexible support part is provided with a second guide hole that slides with the second guide column, and the flexible support part is provided with a vertical movable groove that is connected to the second guide hole and is located below the second guide hole.

[0014] In this solution, the guide post is limited by the guide hole so that it can slide smoothly. At the same time, a movable groove is provided so that the top layer will not be hindered from squeezing the positive graphene detector downward through the trigger, effectively ensuring the detection accuracy.

[0015] Preferably, as an improvement, the number of the first guide posts and the number of the second guide posts are both two, and the trigger is located between the two first guide posts and the two second guide posts.

[0016] In this solution, by providing two first guide posts and two second guide posts, the sliding of the top layer is made smoother, thereby further improving the detection accuracy.

[0017] Preferably, as an improvement, the first guide post and the second guide post are both located in the mounting groove, and the circumferential graphene detector is located below the first guide post and the second guide post.

[0018] In this solution, the circumferential graphene detector is located below the first guide column and the second guide column to prevent the circumferential graphene detector from obstructing the lateral movement of the top layer, so that the circumferential graphene detector can accurately detect the lateral displacement of the top layer, thereby deriving the magnitude of the lateral shear force and achieving more accurate pressure detection.

[0019] Preferably, as an improvement, the trigger is a cylindrical trigger column, a plurality of circumferential graphene detectors are evenly arranged around the trigger column, and the bending radius of the circumferential graphene detectors is equal to the bending radius of the outer wall of the trigger column.

[0020] In this solution, the trigger is set in a cylindrical shape, so that the trigger can fit well with the circumferential graphene detector, so that when the top layer is subjected to lateral shear force, the magnitude of the lateral shear force can be detected quickly and accurately; at the same time, because the circumferential graphene detector fits with the cylindrical trigger, the circumferential graphene detector is curved, so when the trigger is reset and the detection is completed, the restoring force of the circumferential graphene detector itself can assist the detector to reset more accurately and quickly, and even in the case of multiple detections, the circumferential graphene detector has good detection accuracy.

[0021] Preferably, as an improvement, the number of the circumferential graphene detectors is four or eight.

[0022] In this solution, the number of circumferential graphene detectors is set to four or eight, matching the four directions corresponding to the X and Y directions, so as to accurately detect the direction in which the top layer is subjected to shear force and achieve more accurate three-dimensional pressure detection.

[0023] Preferably, as an improvement, a flexible filling portion is provided between the circumferential graphene detector and the flexible support portion.

[0024] In this solution, a flexible filling portion is provided between the circumferential graphene detector and the flexible support portion, so that the circumferential graphene always maintains contact with the trigger without affecting the deformation of the circumferential graphene detector to detect pressure, thereby accurately completing detection when the trigger undergoes slight displacement, effectively improving detection accuracy.

[0025] A method for preparing a three-dimensional pressure sensor, characterized in that it includes the following steps:

[0026] Step 1: Connect the bottom layer and the forward graphene detector, connect the forward graphene detector and at least four circumferential graphene detectors to the top surface of the bottom layer, and evenly distribute all the circumferential graphene detectors around the forward graphene detector;

[0027] Step 2: Connect the top layer to the trigger, with the bottom surface of the top layer facing upwards, and then connect the trigger to the bottom surface of the top layer; then connect the flexible support portion to the bottom surface of the top layer so that the trigger is located in the mounting groove of the flexible support portion;

[0028] Step 3: Install the guide connector between the flexible support portion and the bottom surface of the top layer;

[0029] Step 4: Final assembly: Flip the top layer with the guide connector installed in step 4 180°, and then move the top layer to the top of the bottom layer so that the side walls of the trigger are in contact with the circumferential graphene detector at the same time, and the bottom of the trigger is facing and in contact with the forward graphene detector, and then connect the flexible support part to the top surface of the bottom layer.

[0030] Preferably, as an improvement, the guide connector in step four includes a first guide column and a second guide column that are perpendicular to each other and slidably connected, the first guide column is integrally formed on the bottom surface of the top layer, the second guide column is provided with a first guide hole that slides with the first guide column, the flexible support portion is provided with a second guide hole that slides with the second guide column, and the flexible support portion is provided with a movable groove connected to the second guide hole on the side away from the top layer. When installing the guide connector, first insert the first guide column into the first guide hole, and then push the second guide column into the second guide hole through the movable groove.

[0031] In this solution, by setting up a movable groove, not only can the movable groove be used to allow the top layer to move downward to squeeze the positive graphene detector, but the second guide column can also be easily installed by relying on the movable groove. The structure is simple and the installation is convenient. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 This is a schematic diagram of embodiment 1 of the present invention.

[0033] Figure 2 for Figure 1 Exploded diagram.

[0034] Figure 3 for Figure 1 Schematic diagram after hiding the top layer.

[0035] Figure 4 This is a schematic diagram of the second embodiment of the present invention after the top layer is hidden. DETAILED DESCRIPTION

[0036] The following is further described in detail through specific implementation methods:

[0037] The figure marks in the drawings of the specification include: bottom layer 1, top layer 2, forward graphene detector 3, trigger column 4, flexible support part 5, mounting groove 501, movable groove 502, circumferential graphene detector 6, first guide column 7, second guide column 8, first guide hole 801, and flexible filling part 9.

[0038] Example 1

[0039] This embodiment 1 is basically as shown in the attached Figure 1-Figure 3As shown: A three-dimensional pressure sensor includes a bottom layer 1 and a top layer 2 arranged parallel to the bottom layer 1. The bottom layer 1 and the top layer 2 are both arranged horizontally. The bottom layer 1 and the top layer 2 both use flexible printed circuit boards. A trigger and a positive graphene detector 3 are provided in sequence from the top layer 2 downward. The trigger is a cylindrical trigger column 4. The top surface of the trigger column 4 is connected to the bottom surface of the top layer 2, and the bottom surface of the trigger column 4 is connected to the positive graphene detector 3. The positive graphene detector 3 is connected to the top surface of the bottom layer 1, and the area of the positive graphene detector 3 is smaller than that of the trigger column 4; the top surface of the bottom layer 1 is connected with a flexible support portion 5 whose height is lower than the top layer 2. In this embodiment, the top surface of the flexible support portion 5 is flush with the bottom surface of the top layer 2, and a mounting groove 501 is opened in the middle of the flexible support portion 5. The positive graphene detector 3 is located in the middle of the mounting groove 501.

[0040] Combine Figure 2 and Figure 3 At least four circumferential graphene detectors 6 are connected between the forward graphene detector 3 and the flexible support portion 5. In this embodiment, there are four circumferential graphene detectors 6, with their bottoms connected to the top surface of the bottom layer 1. The four circumferential graphene detectors 6 are evenly arranged on the front, back, left, and right sides of the trigger post 4. The bending radius of the circumferential graphene detectors 6 is equal to the bending radius of the outer wall of the trigger post 4, ensuring good contact between the circumferential graphene detectors 6 and the sidewalls of the trigger post 4. Both the circumferential graphene detectors 6 and the forward graphene detector 3 are made of graphene foam. When subjected to external force, the cell walls of graphene foam contact each other, causing the electrical resistance of the graphene foam to change. The graphene detector in this embodiment utilizes this property to manufacture. When external pressure acts on the graphene detector, the graphene detector calculates the pressure by detecting the deformation, thereby achieving pressure measurement. At the same time, the flexible support portion 5 and the trigger column 4 in this embodiment are both made of superelastic material, for example, polydimethylsiloxane (PDMS), so that the trigger column 4 and the flexible support portion 5 have good flexibility, so that the three-dimensional pressure sensor in this embodiment can be applied to the field of flexible pressure sensors. When the top layer 2 is subjected to external shear force, the force exerted on the top layer 2 can be transmitted to the forward graphene detector 3 and the circumferential graphene detector 6 through the trigger column 4, and the forward graphene detector 3 and the circumferential graphene detector 6 are used to detect the three-dimensional pressure exerted on the top layer 2.

[0041] In order to ensure that the external force exerted on the top layer 2 is transmitted to the forward graphene detector 3 and the circumferential graphene detector 6 more stably and accurately, a guide connector is connected between the top layer 2 and the flexible support portion 5 in this embodiment. Under the guiding connection of the guide connector, the top layer 2 can be moved horizontally on the top surface of the flexible support portion 5. The guide connector includes a first connector and a second connector that are perpendicular to each other. The first connector is a first guide column 7 integrally formed on the bottom surface of the top layer 2. The second connector includes a second guide column 8 that is slidably engaged with the flexible support portion 5. Specifically, a second guide hole that is slidably engaged with the second guide column 8 is provided on the flexible support portion 5, so that the second guide column 8 can slide in the forward and backward directions along the flexible support portion 5. At the same time, a first guide hole 801 that is slidably engaged with the first guide column 7 is provided on the side wall of the second guide column 8, so that the first guide column 7 can slide horizontally left and right relative to the second guide column 8. The sliding directions of the first guide column 7 and the second guide column 8 are perpendicular to each other.

[0042] like Figure 2 As shown, there are two first guide posts 7 and two second guide posts 8, and the trigger post 4 is located between the two first guide posts 7 and the two second guide posts 8. The bottom of the flexible support portion 5 is provided with a movable groove 502 upwardly connected to the second guide hole, and the movable groove 502 provides a movable space for the second guide post 8 to move in the vertical direction. Figure 3 The first guide column 7 and the second guide column 8 are both located in the mounting groove 501, so that the first guide column 7, the second guide column 8, the circumferential graphene detector 6, the forward graphene detector 3 and the trigger column 4 are all located in the closed space in the mounting groove 501, effectively reducing the influence of external impurities on the three-dimensional pressure detection and improving the detection accuracy; at the same time, the height of the circumferential graphene detector 6 is lower than the first guide column 7 and the second guide column 8, avoiding the first guide column 7 and the second guide column 8 from hindering the detection of the circumferential graphene detector 6.

[0043] In this embodiment, due to the provision of a forward graphene detector and multiple circumferential graphene detectors 6, when the top layer 2 receives external three-dimensional pressure, the forward graphene detector can detect the longitudinal pressure of the top layer 2 in the Z direction, and the circumferential graphene detector 6 can detect the lateral pressure in the X and Y directions. Combining the detection results of the forward graphene detector 3 and the circumferential graphene detector 6, the three-dimensional pressure can be detected more accurately, with the characteristics of high sensitivity. At the same time, in this embodiment, by providing a guide connector, the top layer 2 can be moved more easily relative to the bottom layer 1 in the plane formed by the X and Y directions, so that the circumferential graphene detector 6 can detect the shear force in the X and Y directions more quickly and accurately, making the detection result more accurate. The flexible support portion 5, trigger column 4, first guide column 7 and second guide column 8 in this embodiment are all made of superelastic material, and the bottom layer 1 and top layer 2 use flexible printed circuit boards, so that the overall flexibility of the three-dimensional pressure sensor is better, so that the three-dimensional pressure sensor in this embodiment can be applied to the field of detection of human physiological characteristics.

[0044] A method for preparing a three-dimensional pressure sensor comprises the following steps:

[0045] Step 1: Connect the bottom layer 1 and the forward graphene detector 3. First, lay the bottom layer 1 flat so that the top surface of the bottom layer 1 faces upward. Then, connect the forward graphene detector 3 and the four circumferential graphene detectors 6 to the top surface of the bottom layer 1. The four circumferential graphene detectors 6 are respectively arranged on the front, back, left, and right sides of the forward graphene detector 3.

[0046] Step 2: Connect the top layer 2 and the trigger post 4. Flip the top layer 2 180° so that its bottom surface faces upward. Then flip the trigger post 4 180° so that the top of the trigger post 4 (the trigger post 4 is now in the flipped state) is connected to the bottom surface of the top layer 2. Then, connect the flexible support portion 5 to the bottom surface of the top layer 2 so that the trigger post 4 is located in the mounting groove 501 of the flexible support portion 5.

[0047] Step 3: Install the guide connector. Install the guide connector between the flexible support portion 5 and the bottom surface of the top layer 2. Specifically, first insert the two first guide posts 7 into the first guide holes 801 on the second guide posts 8, so that the two second guide posts 8 are located on the left and right sides of the trigger post 4. Then, push the second guide post 8 into the second guide hole through the movable groove 502, so that the first guide post 7 and the second guide post 8 are both installed in the installation groove 501. At this time, the top layer 2 can drive the first guide post 7 to slide relative to the second guide post 8. At the same time, the top layer 2, the first guide post 7 and the second guide post 8 can slide relative to the flexible support portion 5, so that the top layer 2 can move in the plane formed by the X and Y directions.

[0048] Step 4, final assembly, flip the top layer 2 with the guide connector installed in step 4 180°, and then move the top layer 2 to the top of the bottom layer 1, so that the side walls of the trigger column 4 are simultaneously in contact with the side walls of the four circumferential graphene detectors 6, and the bottom of the trigger column 4 is facing and in contact with the forward graphene detector 3, and then connect the flexible support part 5 to the top surface of the bottom layer 1, so that the first guide column 7, the second guide column 8, the forward graphene detector 3, the circumferential graphene detector 6 and the trigger column 4 are all sealed in the installation groove 501. Since the top layer 2 is a flexible printed circuit board and the flexible support part 5 is a superelastic material, when the top layer 2 is subjected to external three-dimensional pressure, the top layer 2 can drive the trigger column 4 to displace along the axial or radial direction of the trigger column 4. When the top layer 2 is subjected to the force along the axial direction of the trigger column 4, the trigger column 4 transmits the pressure to the forward graphene detector 3, and the forward graphene detector 3 is used to detect the Z-direction pressure; when the top layer 2 is subjected to lateral shear force, the top layer 2 acts on the trigger column 4, causing the trigger column 4 to laterally squeeze one or two circumferential graphene detectors 6, and the circumferential graphene detector 6 is used to detect the lateral shear force applied to the top layer 2.

[0049] Example 2

[0050] The difference between the second embodiment and the first embodiment is that: Figure 4 As shown, in this embodiment, a flexible filling portion 9 is provided between the circumferential graphene detector 6 and the side wall of the flexible support portion 5. The flexible filling portion 9 is preferably made of silicone rubber. The height of the flexible filling portion 9 is lower than the circumferential graphene detector 6. Under the flexible support of the flexible filling portion 9, the circumferential graphene detector 6 can be attached to the side wall of the trigger column 4 in real time, so that when the top layer 2 is subjected to lateral shear force and a small lateral displacement occurs, the circumferential graphene detector 6 can quickly and accurately detect the magnitude of the lateral shear force, thereby achieving more accurate pressure detection; and when the top layer 2 is no longer subjected to external pressure, the flexible filling portion 9 can assist the circumferential graphene detector 6 in resetting, so that the circumferential graphene detector 6 can still maintain a high detection accuracy in repeated detections, and is conducive to extending the service life of the circumferential graphene detector 6.

[0051] The above is only an embodiment of the present invention, and the common knowledge such as the specific technical solutions and / or characteristics in the solution are not described in detail here. It should be pointed out that for those skilled in the art, without departing from the technical solution of the present invention, several variations and improvements can be made, which should also be regarded as the scope of protection of the present invention, and these will not affect the effect of the implementation of the present invention and the practicality of the patent. The scope of protection required by this application shall be based on the content of its claims, and the specific implementation methods and other records in the description can be used to interpret the content of the claims.

Claims

1. A three-dimensional pressure sensor comprising a bottom layer and a top layer disposed parallel to the bottom layer, characterized in that: A trigger and a forward graphene detector are connected in sequence from the top layer to the bottom layer, a flexible support portion whose height is lower than the top layer is connected to the bottom layer, a mounting groove is opened in the middle of the flexible support portion, the forward graphene detector is located in the mounting groove, and at least four circumferential graphene detectors are connected between the forward graphene detector and the flexible support portion; a guide connection member is connected between the top layer and the flexible support portion for the top layer to move in a plane perpendicular to the flexible support portion; the guide connection member includes a first connection portion and a second connection portion which are perpendicularly arranged to each other, the first connection portion is connected to the top layer and the first connection portion is slidably connected to the second connection portion, the second connection portion is slidably connected to the flexible support portion, and the first connection portion and the second connection portion slide relative to each other. In the direction perpendicular to the relative sliding direction of the second connecting part and the flexible support part; the first connecting part includes a first guide column connected to the bottom of the top layer, the second connecting part includes a second guide column and the second guide column is provided with a first guide hole that slides with the first guide column; the flexible support part is provided with a second guide hole that slides with the second guide column, and the flexible support part is provided with a vertical movable groove that is connected to the second guide hole and is located below the second guide hole; the number of the first guide column and the second guide column are both two, and the trigger is located between the two first guide columns and the two second guide columns; the first guide column and the second guide column are both located in the mounting groove, and the circumferential graphene detector is located below the first guide column and the second guide column.

2. A three-dimensional pressure sensor according to claim 1, characterized in that: The trigger is a cylindrical trigger column, and a plurality of circumferential graphene detectors are evenly arranged around the trigger column, and the bending radius of the circumferential graphene detectors is equal to the bending radius of the outer wall of the trigger column.

3. The three-dimensional pressure sensor according to claim 2, characterized in that: The number of the circumferential graphene detectors is four or eight.

4. The three-dimensional pressure sensor according to claim 1, characterized in that: A flexible filling portion is provided between the circumferential graphene detector and the flexible support portion.

5. A method for preparing a three-dimensional pressure sensor, for preparing a three-dimensional pressure sensor according to any one of claims 1 to 4, characterized in that: The steps include: Step 1: Connect the bottom layer and the forward graphene detector, connect the forward graphene detector and at least four circumferential graphene detectors to the top surface of the bottom layer, and evenly distribute all the circumferential graphene detectors around the forward graphene detector; Step 2: Connect the top layer to the trigger, with the bottom surface of the top layer facing upwards, and then connect the trigger to the bottom surface of the top layer; then connect the flexible support portion to the bottom surface of the top layer so that the trigger is located in the mounting groove of the flexible support portion; Step 3: Install the guide connector between the flexible support portion and the bottom surface of the top layer; Step 4: Final assembly: Flip the top layer with the guide connector installed in step 4 180°, and then move the top layer to the top of the bottom layer so that the side walls of the trigger are in contact with the circumferential graphene detector at the same time, and the bottom of the trigger is facing and in contact with the forward graphene detector, and then connect the flexible support part to the top surface of the bottom layer.

6. The method for preparing a three-dimensional pressure sensor according to claim 5, wherein: The guide connector in step four includes a first guide column and a second guide column that are perpendicular to each other and slidably connected. The first guide column is integrally formed on the bottom surface of the top layer, and the second guide column is provided with a first guide hole that slides with the first guide column. The flexible support portion is provided with a second guide hole that slides with the second guide column, and the flexible support portion is provided with a movable groove connected to the second guide hole on the side away from the top layer. When installing the guide connector, first insert the first guide column into the first guide hole, and then push the second guide column into the second guide hole through the movable groove.

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