Pressure sensor based on beam bridge type structure and pressure sensor array thereof

Abstract

The utility model provides a pressure sensor based on a beam bridge type structure and a preparation method thereof, the pressure sensor comprises at least one strain sensor, a bridge arm and a frame, the strain sensor is arranged on the frame through the bridge arm, the bridge arm comprises a long bridge arm and a short bridge arm, a sensitive part of the strain sensor is clamped between the long bridge arm and the short bridge arm, and the strain sensor is arranged on the frame. The frame is provided with a first end and a second end which are separated from each other, and an integral structure formed by the strain sensor and the bridge arm crosses the first end and the second end of the frame and is fixed on the first end and the second end of the frame, so that the bridge arm and the strain sensor are suspended and the electrode side of the strain sensor is arranged on the frame; one side of the sensitive part of the strain sensor clings to the inner edge of the frame. The pressure sensor provided by the utility model realizes continuous sensing of a pressure position so as to solve the problems that a traditional pressure sensor is easy to damage, poor in flexibility and discrete in pressure detection.

Description

TECHNICAL FIELD

[0001] The utility model belongs to sensing technology field, especially a pressure sensor and pressure sensor array thereof based on beam bridge type structure. BACKGROUND

[0002] Sensor is the information conversion of non-electric physical quantity of outside measured for electric quantity output device corresponding to it, convenient for subsequent transmission and processing of the information extracted, it is a very important link to complete automatic measurement. Pressure sensor is the device that can convert the changing pressure signal in external environment into the corresponding resistance or capacitance signal. According to different working principles, pressure sensor can be divided into capacitive, piezoresistive, piezoelectric and friction electrification type etc. Different types of pressure sensors have their advantages and disadvantages, and need to be selected according to specific application occasions.

[0003] Capacitive pressure sensor is the conversion of pressure signal into capacitance signal. It can be regarded as a parallel plate capacitor generally, and its capacitance changes after the dielectric constant of dielectric layer, acting area and the distance between upper and lower plates change due to pressure, thereby realizing pressure sensing.

[0004] Piezoresistive pressure sensor is made of material with piezoresistive effect, and its output signal is resistance change, and this change is often caused by the change of its size and resistivity.

[0005] The principle of piezoelectric pressure sensor is that when sensitive material is subjected to pressure, the positive and negative charge centers inside move relatively to generate voltage, and this voltage will change with the change of the direction and size of pressure. Its advantage is that it does not need external power supply, and the defect is that it can only detect dynamic pressure change, and cannot detect static pressure change.

[0006] Friction electrification type pressure sensor is developed based on the coupling effect between contact electrification and electrostatic induction. It uses the principle that different materials rub each other and accumulate equal and opposite charges when subjected to pressure, thereby generating voltage and current. This kind of sensor does not need external power supply, but still can only detect dynamic pressure, and cannot detect static pressure.

[0007] In addition, for pressure sensor, its material will also have certain influence on sensing mechanism and performance. In recent years, flexible pressure sensor has attracted widespread attention. For flexible pressure sensor, commonly used materials include metal-based materials, carbon-based materials, conductive polymers and other new materials.

[0008] Metal-based materials mainly include liquid metal, metal particles and nanowires. Pressure sensors made of such materials often exhibit excellent mechanical properties, good electrical conductivity and long-term stability. For example, pressure sensors made of silver nanowires as materials can achieve high sensitivity.

[0009] Carbon-based materials generally include carbon nanotubes, graphene and its derivatives, and carbon black. Its advantages are rich in resources, simple preparation method and low cost, so it is more suitable for industrial production and wide application.

[0010] Commonly used conductive polymers include polypyrrole and MXene, and pressure sensors made of these materials often have high sensitivity and low detection limit.

[0011] At present, pressure sensors have made great progress. In recent years, flexible pressure sensors have also been widely studied and achieved fruitful results. However, there are still a series of problems with pressure sensors. For example, in order to obtain pressure signals, conventional pressure sensors are directly placed under the pressure action point, which makes them vulnerable to damage by sharp and high heat. This is particularly true for flexible pressure sensors that need to have high flexibility and thus have to use flexible materials as packaging materials. In addition, for pressure sensor arrays prepared by using pressure sensors, the traditional method is to place a separate pressure sensor under each point of the array, which leads to an exponential increase in the number of pressure sensors as the pixel rises, and the cost also increases. At the same time, the pressure detection prepared by this method is discrete, and the pressure value between two adjacent pixels is actually an interpolated result, which may not be the true value.

[0012] The utility model patent CN213688743U discloses a compact beam type pressure sensor, which comprises a sealed box composed of a stainless steel strain beam and a cover plate. A Wheatstone bridge is installed inside the sealed box. The Wheatstone bridge is composed of four resistance strain gauges. An insulating layer is arranged between the top of the Wheatstone bridge and the bottom of the cover plate. The bottom is attached to the top of the stainless steel strain beam. The internal space of the sealed box is completely filled with the Wheatstone bridge and the insulating layer. The two adjacent resistance strain gauges are electrically connected by a copper sheet. The cover plate and the insulating layer are both provided with an outlet. After assembly, the copper sheet extends upward and protrudes from the inside of the outlet. The internal space of the sealed box is fully utilized. The two adjacent resistance strain gauges are electrically connected by the copper sheet. The main defects of the beam type pressure sensor are: the whole component is composed of rigid materials, which lacks sufficient flexibility, has multiple layers, is relatively thick, and is not light enough; and it is not convenient to build a pressure sensor array. Utility model content

[0013] The utility model discloses a pressure sensor based on beam bridge structure and pressure sensor thereof, realized the continuous perception to pressure position to solve the traditional pressure sensor is vulnerable, the poor flexibility and the problem of pressure detection discrete.

[0014] To solve the above technical problems, the technical scheme of the utility model is:

[0015] According to one aspect of the utility model, a pressure sensor based on beam bridge structure is provided, which comprises at least one strain sensor, a bridge arm and a frame. The strain sensor is arranged on the frame through the bridge arm. The strain sensor comprises a wire, a packaging layer, an electrode, a circuit layer and a base layer. The circuit layer has a dense circuit part as a sensitive part of the strain sensor. The Young's modulus of the material of the base layer is between 1MPa and 10GMPa and is less than or equal to the Young's modulus of the material of the bridge arm. The bridge arm comprises a long bridge arm and a short bridge arm. The sensitive part of the strain sensor is clamped between the long bridge arm and the short bridge arm. The thickness of the bridge arm is greater than or equal to the thickness of the strain sensor and less than five times the thickness of the strain sensor. The width of the bridge arm is greater than or equal to the thickness of the sensitive part of the strain sensor. The frame has a first end and a second end spaced apart. The frame is arranged below the strain sensor. The overall structure of the strain sensor and the bridge arm spans the first end and the second end of the frame and is fixed on the first end and the second end of the frame, so that the bridge arm and the strain sensor are suspended and the electrode side of the strain sensor is on the frame. One side of the sensitive part of the strain sensor is close to the inner edge of the frame.

[0016] Optionally, in the pressure sensor based on the beam bridge structure, the material of the bridge arm is selected from at least one of a metal material, polyimide, polyurethane and polyethylene. The material of the circuit layer comprises a metal material, a carbon-based material and a high molecular material. The material of the base layer is selected from at least one of styrene-ethylene-butylene-styrene thermoplastic elastomer (SBS), polyimide, polyethylene, PDMS or polyurethane (PU). The loading and combining mode of the bridge arm and the strain sensor is hot pressing or sticking.

[0017] Optionally, in the pressure sensor based on the beam bridge structure, the short bridge arm is arranged adjacent to one end of the wire of the strain sensor.

[0018] Optionally, in the pressure sensor based on the beam bridge structure, the pressure sensor comprises one strain sensor. One side of the sensitive part of the strain sensor is close to one end edge of the long bridge arm, and the other side is close to the frame. The two ends of the long bridge arm are fixed on the first side of the frame, and the short arm is fixed on the second side of the frame.

[0019] Optionally, in the pressure sensor based on the beam bridge structure, two strain sensors are arranged below the opposite positions of the long bridge arm respectively, the sensitive part of the strain sensor is close to the edge of the long bridge arm on one side and close to the frame on the other side, and the two strain sensors are symmetrically arranged about the middle point of the long bridge arm.

[0020] Optionally, in the pressure sensor based on the beam bridge structure, the pressure sensor comprises two strain sensors, the frame is a circular ring, the sensitive part of the two strain sensors is close to the inner arc of the frame at the two ends on one side, the whole is suspended, and the middle is connected through the long bridge arm, and the long bridge arm and the sensitive part of the strain sensor are both suspended and parallel to the arrangement surface.

[0021] Optionally, in the pressure sensor based on the beam bridge structure, the pressure sensor comprises two strain sensors, the long bridge arm is designed as an L shape, the circuit layer of the two strain sensors is printed on the same substrate layer, and the same packaging layer is used for packaging, the sensitive parts of the two strain sensors are perpendicular to each other and do not overlap or contact.

[0022] According to another aspect of the present application, a pressure sensor array is provided, comprising a plurality of the pressure sensor based on the beam bridge structure, and the plurality of pressure sensors are arranged in a cross shape on the frame to form a cross-shaped pressure sensor array or are arranged in parallel along the frame.

[0023] In the pressure sensor array, 10 strain sensors are included, the frame is a rectangle, and one pressure sensor based on the beam bridge structure is arranged on every 10 mm of two adjacent straight edges of the rectangular frame.

[0024] According to still another aspect of the present application, a preparation method of the pressure sensor based on the beam bridge structure is provided, comprising the following steps:

[0025] Step 1: manufacturing of the strain sensor, comprising:

[0026] Step 11: preparing liquid metal ink, the volume composition is 3 parts of gallium-indium-tin alloy and 1 part of n-decanol, and the ink is obtained by ultrasonic treatment for 1 minute;

[0027] Step 12: performing pattern design, then manufacturing a silk screen printing plate, performing silk screen printing on the substrate layer, and drying to obtain a circuit layer;

[0028] Step 13: cutting an electrode pattern on a thermoplastic polyurethane film by using a laser cutting technology, placing an FPC electrode on the electrode layer, then covering the polyurethane film on the FPC electrode, and performing hot pressing to package the circuit;

[0029] Step 14: welding the lead wire and the electrode together,

[0030] Step 2: the making and assembling of the bridge arm, including:

[0031] Step 21: according to the size of the strain sensor and the specific application scenario, selecting a suitable flexible material as the bridge arm material and processing it into a suitable size to obtain the bridge arm, and placing the circuit layer so that the edge of the circuit layer with a dense circuit is close to the edge of the frame;

[0032] Step 22: hot pressing or pasting the bridge arm to the strain sensor, and ensuring that the edge of the bridge arm is flush with the edge of the circuit layer;

[0033] Step 23: fixing the edges of the long bridge arm and the short bridge arm to the frame, and having a spacing at both ends of the frame so that the middle part of the frame is in a suspended state.

[0034] Compared with the prior art, the pressure sensor based on the beam bridge structure has the following beneficial effects:

[0035] The pressure sensor based on the beam bridge structure of the utility model is used for converting the pressure signal into a strain signal that can be detected by the strain sensor through the bridge arm structure, and solves the problems of the traditional pressure sensor that is easily damaged and has poor flexibility. The sensor array made of the pressure sensor significantly reduces the requirement of the traditional pressure sensor array on the number of sensors. Specifically, the pressure signal can be converted into a strain signal that can be detected by the strain sensor through the beam bridge structure, and the strain is concentrated on the strain sensor, and the sensitivity and the detection range of the sensor can be adjusted by adjusting the material, the width and the length of the extension arm. Moreover, compared with the traditional method of directly placing the pressure sensor at the pressure action point, the beam bridge structure places the sensor circuit part outside the action point, thereby reducing the possibility that the sensor is damaged due to the pressure action. When one strain sensor is arranged at each end of an extension layer, the continuous monitoring of the pressure size and the position on the strip can also be realized by analyzing the readings of the two sensors. For the pressure sensor detection array composed of multiple sensors, compared with the traditional method of setting one pressure sensor at one detection point, the number of required sensors can be significantly reduced by arranging the sensors at the edges of the array. BRIEF DESCRIPTION OF DRAWINGS

[0036] In order to more clearly illustrate the specific embodiments of the utility model or the technical solutions in the prior art, the drawings needed to be used in the specific embodiments or the prior art description will be briefly introduced.

[0037] Figure 1 It is a principle structure diagram for the pressure measurement and position detection of the pressure sensor based on the beam bridge structure of the utility model.

[0038] Figure 2 It is a principle curve diagram for the pressure measurement and position detection of the pressure sensor based on the beam bridge structure of the utility model.

[0039] Figure 3 The x, y, z orientation patterns of the pressure sensor based on the beam-bridge structure of this utility model are shown.

[0040] Figure 4 for Figure 1 An exploded view of the components of a pressure sensor based on a beam-bridge structure.

[0041] Figure 5 This is a schematic diagram showing the positions of two strain sensors placed on both sides of the long bridge arm, which is a preferred embodiment of this utility model.

[0042] Figure 6 This is a structural diagram of a plurality of pressure sensor arrays according to another preferred embodiment of the present invention;

[0043] Figure 7 This is a structural diagram of the dual-sided pressure sensor array of this utility model;

[0044] Figure 8 This is a structural diagram of the annular double-sided pressure sensor of this utility model;

[0045] Figure 9 This is a structural diagram of the orthogonal pressure sensor of this utility model;

[0046] Figure 10 This is a structural diagram of the circular orthogonal pressure sensor array of this utility model;

[0047] Figure 11 This is a structural diagram of the circular double-sided array pressure sensor array of this utility model.

[0048] Icon labels:

[0049] 1-Strain sensor, 101-Wire, 102-Encapsulation layer, 103-Electrode, 104-Circuit layer, 1041-Sensing element, and 105-Base layer.

[0050] 2-bridge arm, 201-long bridge arm and 202-short bridge arm.

[0051] 3-Framework. Detailed Implementation

[0052] The following detailed description of a pressure sensor based on a beam-bridge structure, with reference to the accompanying drawings and specific embodiments, illustrates the present invention.

[0053] This invention utilizes a strain sensor mounted on a beam bridge structure, transforming the strain sensor 1 into a pressure sensor. The strain sensor and the bridge's overall structure are positioned at both ends of the frame, preventing the pressure from directly acting on them and thus avoiding damage to the relatively fragile sensor components. Furthermore, placing strain sensors at both ends of the frame allows for the determination of the pressure's application point and magnitude by utilizing the different responses of the strain sensors at the same location on both ends of the frame to the same pressure. This detection also provides spatial continuity on the beam bridge. The pressure sensor of this beam bridge structure is compact, portable, and possesses high flexibility and reliability.

[0054] The pressure sensor of this utility model with a beam-bridge structure converts the pressure signal perpendicular to the upper surface of the sensor into a strain signal in the parallel direction that is easily obtained by the strain sensor after attaching an extension layer to the strain sensor 1 and mounting the sensor as a whole on any frame. This enables pressure detection using a strain sensor.

[0055] like Figures 1-11 As shown, the pressure sensor based on the beam-bridge structure of this utility model includes at least one strain sensor 1, a bridge arm 2 and a frame 3. The strain sensor 1 is mounted on the frame 3 via the bridge arm 2, and the surface on which it is mounted is called the mounting surface.

[0056] Strain sensor 1 includes a wire 101, an encapsulation layer 102, an electrode 103, a circuit layer 104, and a substrate layer 105. The wire 101 is disposed adjacent to the short bridge arm 202; the densely packed portion of the circuit layer 104 is the sensitive part 1041 of the strain sensor. Figure 4 The sensing element 1041 is a serpentine circuit used to sense changes in strain. Electrode 103 and circuit layer 104 are encapsulated between substrate layer 105 and encapsulation layer 102. The encapsulation layer material is selected from transparent thermoplastic polyurethane or transparent polydimethylsiloxane (PDMS), therefore, as shown in the attached figures (e.g.) Figure 1 The dense circuitry of circuit layer 104 can be seen in the diagram.

[0057] The circuit layer 104 of the strain sensor uses sensitive materials, mainly including three categories: metallic materials (including metal nanosheets, nanowires, nanoparticles and liquid metals, etc.), carbon-based materials (including carbon black, carbon nanotubes and graphene and their oxides), and polymeric materials (mainly including polyaniline, polypyrrole and their derivatives). The substrate layer 105 of the strain sensor is made of at least one of styrene-ethylene-butene-styrene thermoplastic elastomer (SBS), polyimide, polyethylene, PDMS or polyurethane (PU). The Young's modulus of the substrate layer 105 is between 1 MPa and 10 GPa, and it is required to be less than or equal to the Young's modulus of the bridge arm 2.

[0058] Bridge arm 2 includes a long bridge arm 201 and a short bridge arm 202. The long bridge arm 201 is used to withstand pressure, and the short bridge arm 202 assists in mounting the strain sensor 1 on the frame 3. The strain sensor 1 is mounted on the frame 3 via the bridge arm 2, and the sensitive part of the strain sensor is located between the long bridge arm 201 and the short bridge arm 202.

[0059] Preferably, such as Figure 1 and Figure 4 As shown, a pressure sensor based on a beam-bridge structure includes a strain sensor 1, a bridge arm 2, and a frame 3. The sensitive part 1041 of the strain sensor 1 ( Figure 4 One side is tightly attached to one edge of the long bridge arm 201, and the other side is tightly attached to the frame 3. One end of the long bridge arm 201 is fixed to the first side of the frame 3, and the short arm 202 is fixed to the second side of the frame 3.

[0060] Preferably, such as Figure 5 As shown, it includes two strain sensors 1 located on both sides of the long bridge arm 2 (see Embodiment 3 for the specific structure).

[0061] The core manufacturing steps of this invention involve the fabrication and assembly of the bridge arm structure. After determining the application scenario and other factors, and selecting a suitable strain sensor 1, the bridge arm 2 is assembled. The assembly of the bridge arm 2 includes: selecting the bridge arm material, designing the length, width, and thickness according to specific requirements; selecting a suitable processing method to prepare the material to the appropriate size based on the specific material; and finally, using glue or hot pressing to combine the bridge arm structure with the strain sensor. It is important to note that, in order to achieve the function of the bridge arm structure, the Young's modulus of the bridge arm 2 material must be higher than that of the strain sensor, or its thickness must be higher than that of the strain sensor; otherwise, the performance will be significantly affected.

[0062] The spacing, length, width, thickness, and Young's modulus of the long bridge arm 201 and the short bridge arm 202 all affect the results. The material of the bridge arm 2 is selected from at least one of metal, polyimide, polyurethane, and polyethylene. Generally, the modulus of the bridge arm material is required to be greater than the modulus of the substrate layer of the strain sensor. The mounting and bonding method between the bridge arm 2 and the strain sensor 1 is hot pressing or bonding, depending on the specific material. The bridge arm 2 is a rectangular thin film with a thickness greater than or equal to the thickness of the strain sensor, but less than five times the thickness of the strain sensor to avoid affecting its overall flexibility. The width is greater than or equal to the sensitive part of the strain sensor and can be customized as needed. The length of the short bridge arm 202 has no special requirements; it only needs to cover the electrode side of the strain sensor and facilitate its attachment to the frame using commercial adhesive tape. The length of the long bridge arm 201 needs to be sufficient to allow it to be attached to the frame 3 at the other end, and to be almost parallel to the mounting plane. The bridge arm 2 is tightly attached to the strain sensor 1, forming a gap between the long bridge arm 201 and the short bridge arm 202. The width of the gap is equal to the width of the sensitive part of the strain sensor, ensuring that the sensitive part of the strain sensor is fully exposed without exposing any other extra parts. The short bridge arm 202 is on the side of the wire 101, and the long bridge arm 201 is on the other side of the sensitive part of the strain sensor. The lengths of the long bridge arm 201 and the short bridge arm 202 are required to fix the integrated structure consisting of the strain sensor and the bridge arm to the frame 3.

[0063] The frame 3 has a first end 31 and a second end 32 spaced apart, with a hollow middle section. The frame 3 is positioned below the strain sensor 1. The frame 3 has a certain height to facilitate pressure-induced deformation. The distance between the two ends of the frame should be such that the bridge arm 2 and the strain sensor 1 are suspended and substantially parallel to the mounting surface. The thickness should be determined according to the range of the force to be measured to avoid the sensor contacting the mounting surface before being fully stressed. One end of the frame 3 is tightly attached to the bottom of the strain sensor 1, ensuring that the electrode side of the strain sensor 1 is on the frame 3. The sensitive part of the strain sensor is tightly attached to the inner edge of the frame 3, and the entire frame is suspended to avoid the influence of friction. The other end of the frame 3 is spaced a certain distance away and is tightly attached to the bottom of the long bridge arm 201 (i.e., one end of the long bridge arm 201 is mounted on the inner edge of the other end of the frame 3). The entire frame 3 is mounted on a hard surface to avoid measurement errors caused by pressure-induced settlement.

[0064] During the measurement process, the three parts of the frame are required to maintain their original shape, therefore they need to have the highest compressive, tensile, and bending resistance, i.e., the highest modulus.

[0065] The principles of pressure measurement and position detection are as follows: Figure 1 , 2As shown, applying pressure to the long bridge arm will cause it to displace, which in turn causes a strain sensor to generate a certain strain, thus enabling pressure detection. The pressure required to produce the same displacement varies at different locations on the long bridge arm; its magnitude roughly follows a quadratic function with an upward-opening trend based on the distance between the pressure point and the strain sensor. When the bridge arm material modulus is low, the farther the pressure point is from the strain sensor, the lower the strain. Therefore, this principle can be used to place a strain sensor on each side of the long bridge arm, thereby achieving continuous detection of the pressure position.

[0066] Integration of beam-bridge type pressure sensors (pressure sensor array): There are two integration methods for fabricating pressure sensor arrays using pressure sensors based on beam-bridge structures: orthogonal integration, which involves arranging several pressure sensors along the x and y directions on a two-dimensional planar frame to form a grid-shaped pressure sensor array; and two-end integration, which involves installing a strain sensor on each side of a single long bridge arm to construct a two-end pressure sensor that can simultaneously detect pressure magnitude and position in one dimension, and arranging several such sensors in parallel along the frame to construct a pressure sensor array. For example... Figure 3 As shown, the x, y, and z directions of the pressure sensor are displayed. A conventional strain sensor 1 can detect deformation in the x and y directions, while the pressure sensor can detect force in the z direction.

[0067] Example 1

[0068] like Figure 1 and 4 As shown, the fabrication method of a pressure sensor based on a beam-bridge structure includes the following specific steps:

[0069] Step 1: Fabrication of the strain sensor, including:

[0070] Step 11: Prepare liquid metallic ink. The volumetric composition is 3 parts gallium indium tin alloy and 1 part n-decanol. Sonicate for 1 minute to obtain the ink.

[0071] Step 12: After designing the pattern, make a screen printing plate, screen print on a base layer 105 with a thickness of 0.1 mm (preferably thermoplastic polyurethane material), and dry it in an oven at 80°C for about 5 minutes to obtain a circuit layer 104 with a thickness of about 10 micrometers.

[0072] Step 13: Use laser cutting technology to cut electrode patterns on thermoplastic polyurethane film, place FPC electrode 103 on electrode layer 102, then cover it with polyurethane film, hot press at 145°C for 15 seconds to encapsulate the circuit.

[0073] Step 14: Use welding technology to weld the wire 101 to the electrode 103 together.

[0074] Step 2: Fabrication and assembly of bridge arm 2:

[0075] Step 21: Based on the size of strain sensor 1 and the specific application scenario, select a suitable flexible material as the bridge arm material and process it into a suitable size to obtain bridge arm 2. Preferably, the long bridge arm 201 is 100mm long and the long and short bridge arms are spaced 5mm apart. The circuit layer of the strain sensor is placed so that the edge of its serpentine circuit part (i.e. the dense part of the circuit layer) is close to the edge of the frame 3.

[0076] Step 22: Press bridge arm 2 onto strain sensor 1 by heat or use commercial adhesive, and ensure that the edge of bridge arm 2 is flush with the edge of circuit layer 104.

[0077] Step 23: Fix the edges of the long bridge arm 201 and the short bridge arm 202 to the frame 3. The two ends of the frame are hollow with a gap. Preferably, the gap between the two ends of the frame is 100mm to ensure that the two are suspended in the middle.

[0078] stress test

[0079] Pressure tests were conducted on a pressure sensor based on a beam-bridge structure. A commercial pressure gauge was used to apply vertical downward pressure to the sensor, with a compression distance of 10 mm. The pressure test locations were selected 10 mm from the edge of the frame. The test results are as follows. Figure 2 PI was used as the bridge arm material. This material has a relatively high tensile modulus (0.3 GPa). In this case, the trend of pressure peak change is basically consistent with the trend of signal peak change, indicating that the pressure value can be detected by observing the change of signal value.

[0080] Example 2

[0081] Silver, a metal with extremely high conductivity and biocompatibility, is commonly used to fabricate flexible strain sensors. Using commercially available silver paste, printed onto polydimethylsiloxane (PDMS) following the steps in Example 1, a similar strain sensor can be prepared. By processing a polyimide film into the shape described in Example 1, firmly mounting it onto the silver paste and PDMS-based strain sensor using commercial double-sided adhesive, and fixing it to a frame, a beam-bridge structure-based pressure sensor using silver paste as the sensing material can be fabricated, demonstrating the versatility of this invention.

[0082] Example 3

[0083] The structure described in this invention enables the determination of the pressure application point, including detection on a one-dimensional interface. This embodiment includes two strain sensors 1, one long bridge arm 201, and two short bridge arms 202. One short bridge arm 202 is positioned near the first frame 31, and the other short bridge arm 202 is positioned near the second frame 32. The two strain sensors 1 are respectively positioned below the long bridge arm 201. One side of the sensitive part of the strain sensor is in close contact with the edge of the long bridge arm 201, and the other side is in close contact with the frame 3. The two strain sensors 1 are symmetrically arranged about the midpoint of the long bridge arm 201. Figure 5 As shown. The specific structure is as follows: Two strain sensors are prepared using the method described in Example 1. Appropriately sized long and short bridge arms are designed. The two strain sensors are glued to both sides of the long bridge arm 201 using commercial adhesive, ensuring that both ends of the long bridge arm 201 are aligned with the edges of the sensor's sensitive portion. Then, the two short bridge arms 202 are glued to the other end of the corresponding strain sensor's sensitive portion, thus completing the construction of this embodiment. Based on Example 1, this structure, through analysis of the signals from both sides of the sensors, avoids the problem of difficulty in determining the pressure application point when only a single strain sensor is used.

[0084] Example 4

[0085] By combining multiple pressure sensors and equipping them with a square frame, a pressure detection matrix can be constructed, which can reduce the number of pressure sensors used in traditional pressure detection matrices. For example... Figure 6 As shown, on two adjacent right-angled sides of a rectangular frame, one beam-bridge type pressure sensor from Embodiment 1 is placed at a fixed distance of 10mm. The frame used is a 100mm*100mm acrylic frame, and 10 pressure sensors 1 from Embodiment 1 are used. The sensors are woven in an alternating overlapping manner, meaning that the upper arms of adjacent detection points belong to different types of pressure sensors. This makes the detection points as close to the same plane as possible, reducing signal differences that may be caused by the layered weaving method. This achieves pressure detection and positioning within the frame with an accuracy of 25 pixels. Compared to the traditional method, this reduces the number of pressure sensors required by 15. Furthermore, this method can further reduce the number of pressure sensors as the number of pixels increases.

[0086] Example 5

[0087] In Example 2, the pressure sensor, because it also functions as a pressure point detector, can also be used in a pressure detection matrix. For example... Figure 7 As shown, by using dual-sided pressure sensors, the effect of a pressure detection matrix can also be achieved in the frame of Embodiment 3. Specifically, five strain sensors 1 with two aligned mountings as described in Embodiment 3 are placed at 10mm intervals along one side of the rectangular frame, ensuring that the sensitive parts of the strain sensors are suspended in the air and one side is in close contact with the edge of the frame.

[0088] Example 6

[0089] The pressure sensor based on a beam-bridge structure includes two strain sensors 1. A circular frame 3 is designed, with an inner diameter of 50mm and an outer diameter of 60mm. The pressure sensors on both sides are placed within the ring, allowing for the detection of pressure magnitude and location. Figure 8 As shown. Specifically, the sensitive parts of the two strain sensors 1 are closely attached to the inner arc of the two end frames 3, which are aligned, and are suspended in the air. They are connected in the middle by a long bridge arm. The long bridge arm 201 and the sensitive parts of the strain sensors are both suspended in the air and parallel to the mounting surface.

[0090] Example 7

[0091] When using a circular frame, orthogonal pressure sensors can be fabricated through sensor design, and these orthogonal pressure sensors can be used to assist in constructing a circular pressure sensing array, such as... Figure 9 As shown. The manufacturing process of this sensor is the same as in Example 1. The pressure sensor includes two strain sensors (angular perpendicular structure). The circuit layers of the two strain sensors are printed on the same substrate layer and encapsulated with the same encapsulation layer. The sensitive parts of the two sensors are perpendicular to each other and do not overlap or contact. The mounting position and shape of the short bridge arm are similar to those described above, while the long bridge arm is designed as an L-shape to ensure that its outer boundary is aligned with the sensitive parts of the two strain sensors. Figure 10 As shown, the circular frame has an inner diameter of 100mm and an outer diameter of 120mm. A polar coordinate system is established with the center of the circle as the origin. A pressure sensor based on a beam-bridge structure is placed at 0° and 90° respectively, and orthogonal pressure sensors are placed at 30°, 60°, 210° and 240°, thereby realizing the pressure detection and positioning function within the circular frame.

[0092] Example 8

[0093] Using the frame employed in Example 6, the five pressure sensors based on the beam-bridge structure from Example 2 are vertically positioned at angles of 30°, 60°, 90°, 120°, and 150° by adjusting the length of their long bridge arms 201. This design achieves pressure detection and positioning functions similar to those in Example 6 while reducing the number of sensors used. Figure 11 As shown.

[0094] The above embodiments are merely specific implementations of this utility model, used to illustrate the technical solution of this utility model, and not to limit it. The protection scope of this utility model is not limited thereto. Although this utility model has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that any person skilled in the art can still modify or improve the technical solutions described in the foregoing embodiments, or make equivalent substitutions for some of the technical features, within the technical scope disclosed in this utility model; and these modifications, changes, or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of this utility model, and should all be covered within the protection scope of this utility model. Therefore, the protection scope of this utility model should be determined by the protection scope of the claims.

Claims

1. A pressure sensor based on a beam-bridge structure, characterized in that, It includes at least one strain sensor, a bridge arm, and a frame, wherein the strain sensor is mounted on the frame via the bridge arm. The strain sensor includes: a wire, an encapsulation layer, electrodes, a circuit layer, and a substrate layer; the densely packed part of the circuit layer is the sensitive part of the strain sensor, wherein the Young's modulus of the material of the substrate layer is between 1 MPa and 10 GMPa and is less than or equal to the Young's modulus of the material of the bridge arm; The bridge arm includes a long bridge arm and a short bridge arm. The sensitive part of the strain sensor is sandwiched between the long bridge arm and the short bridge arm. The thickness of the bridge arm is greater than or equal to the thickness of the strain sensor and less than five times the thickness of the strain sensor. The width of the bridge arm is greater than or equal to the thickness of the sensitive part of the strain sensor. The frame has a spaced-apart first end and second end, and is positioned below the strain sensor. The integral structure consisting of the strain sensor and the bridge arm spans the first and second ends of the frame and is fixed to the first and second ends of the frame, such that the bridge arm and the strain sensor are suspended and that the electrode side of the strain sensor is on the frame, and the sensitive part of the strain sensor is in close contact with the inner edge of the frame.

2. The pressure sensor based on a beam-bridge structure according to claim 1, characterized in that, The bridge arm is made of at least one of metal, polyimide, polyurethane, and polyethylene; the circuit layer is made of metal, carbon-based, and polymer materials; the base layer is made of at least one of styrene-ethylene-butene-styrene thermoplastic elastomer (SBS), polyimide, polyethylene, PDMS, or polyurethane (PU); and the bridge arm and the strain sensor are mounted and bonded by hot pressing or bonding.

3. The pressure sensor based on a beam-bridge structure according to claim 1, characterized in that, The short bridge arm is positioned near one end of the wire of the strain sensor.

4. The pressure sensor based on a beam-bridge structure according to claim 3, characterized in that, It includes a strain sensor, with one side of the sensitive part of the strain sensor in close contact with one edge of the long bridge arm and the other side in close contact with the frame. One end of the long bridge arm is fixed to the first side of the frame, and the short bridge arm is fixed to the second side of the frame.

5. The pressure sensor based on a beam-bridge structure according to claim 1, characterized in that, The pressure sensor is a two-end pressure sensor, with one strain sensor installed on each side of a single long bridge arm. The sensitive part of the strain sensor is in close contact with the edge of the long bridge arm on one side and in close contact with the frame on the other side. The two strain sensors are symmetrically arranged about the midpoint of the long bridge arm.

6. The pressure sensor based on a beam-bridge structure according to claim 1, characterized in that, The pressure sensor is an orthogonal pressure sensor, consisting of two strain sensors. The long bridge arm is designed in an L-shape. The circuit layers of the two strain sensors are printed on the same substrate layer and encapsulated with the same encapsulation layer. The sensitive parts of the two strain sensors are perpendicular to each other and do not overlap or contact each other.

7. The pressure sensor based on a beam-bridge structure according to claim 1, characterized in that, The pressure sensor includes two strain sensors. The frame is circular. The edge of one side of the sensitive part of the two strain sensors is close to the inner arc of the two end frames, and the whole is suspended. They are connected in the middle by the long bridge arm. The long bridge arm and the sensitive part of the strain sensor are both suspended and parallel to the mounting surface.

8. A pressure sensor array, characterized in that, It includes a plurality of pressure sensors based on a beam-bridge structure as described in any one of claims 1 to 7, wherein the plurality of pressure sensors are orthogonally arranged on the frame to form a grid-shaped pressure sensing array or are arranged in parallel along the frame.

9. The pressure sensor array according to claim 8, characterized in that, It includes 10 strain sensors. The frame is rectangular, and one pressure sensor based on the beam-bridge structure is placed every 10 mm on two adjacent right-angled sides of the rectangular frame.

Images