Novel multifunctional flexible touch sensor

Abstract

The utility model discloses a novel multifunctional flexible tactile sensor which comprises a flexible substrate, the top of the flexible substrate is coated with a bottom electrode, a sub-signal channel is connected to the position, close to the front face, of the edge of the bottom electrode, and the top of the sub-signal channel is covered with a flexible fixing film. The top of the bottom electrode is covered with a pressure sensing microstructure layer, the top of the pressure sensing microstructure layer is provided with a flexible electrode, the top of the flexible electrode is connected with a flexible insulating layer, and the top of the flexible insulating layer is adhered with a dome protruding structure. According to the utility model, the stability among the layers of the material is improved by arranging the flexible liner and the reinforcing member, the durability of equipment is improved, and various complex information such as normal force, tangential force, tangential force direction, material softness, surface texture and the like can be detected in real time by arranging the dome bulge structure, the pressure sensing microstructure layer, the bottom electrode and the sub-signal channel.

Description

Technical Field

[0001] The utility model relates to the technical field of flexible tactile sensors, in particular to a novel multifunctional flexible tactile sensor. Background Art

[0002] In recent years, tactile sensors that simulate human tactile perception have developed rapidly and have gradually become a hotspot in cutting-edge research. At the same time, the development of new sensing materials, manufacturing methods, sensing principles, etc. in recent years has strongly promoted the significant progress of flexible tactile sensors, and a variety of high-sensitivity, high-flexibility, and low-cost flexible tactile sensors have emerged.

[0003] At present, during the production and manufacturing process, most of the existing flexible tactile sensors are fixed directly through simple material stacking and external coating, because this method is conducive to mass production and reducing costs. However, after long-term use, this simple material stacking may cause relative movement between the stacked layers due to sliding or loose contact between the materials, thereby affecting the accuracy of the flexible tactile sensor. Utility Model Content

[0004] The utility model aims to solve the problem in the prior art that simple material stacking may cause relative movement between layers, and proposes a novel multifunctional flexible tactile sensor.

[0005] In order to achieve the above purpose, the utility model adopts the following technical solutions:

[0006] A novel multifunctional flexible tactile sensor comprises a flexible substrate, the top of which is coated with a bottom electrode, the material of the flexible substrate can be polyurethane film, polydimethylsiloxane, polyester, etc., the edge of the bottom electrode is connected to a sub-signal channel near the front, the top of the sub-signal channel is covered with a flexible solid film, the top of the bottom electrode is covered with a pressure sensing microstructure layer, the top of the pressure sensing microstructure layer is provided with a flexible electrode, the front of the flexible electrode is connected to a common electrode, the bottom of the common electrode is provided with a flexible pad film, the top of the flexible electrode is connected to a flexible insulating layer, and the flexible electrode and the common electrode are printed on the bottom of the flexible insulating layer, the bottom electrode and the sub-signal channel as well as the flexible electrode and the common electrode can be made of elastic carbon paste, conductive silver paste, carbon nanotubes, etc., the top of the flexible insulating layer is adhered with a dome protrusion structure, and the outer surface of the dome protrusion structure is covered with a flexible film near the edge.

[0007] Preferably, a flexible pad is adhered to the top of the flexible insulating layer, a reinforcing piece is adhered to the edge of the flexible pad, a card interface is provided on the flexible substrate, and the flexible substrate is fixedly connected to the reinforcing piece via the card interface.

[0008] Preferably, the top of the flexible pad is bonded to the dome protrusion structure, and the flexible solid film is located at the bottom of the flexible pad film.

[0009] Preferably, the bottom of the flexible film is adhered to the top of the flexible substrate near the edge of the bottom electrode, and the inner side of the flexible film is adhered to the outer surface of the dome protrusion structure.

[0010] Preferably, the bottom electrode is composed of five sub-electrodes, and the five sub-electrodes of the bottom electrode are four arc-shaped electrodes surrounding a circular electrode in the middle, and the five sub-electrodes of the bottom electrode are each connected to a corresponding sub-signal channel.

[0011] Preferably, a plurality of microstructure tips are fixed to the bottom of the pressure sensing microstructure layer, and the shapes of the microstructure tips may be a pyramid structure, a hemispherical structure, an irregular structure, etc. The microstructure tips are periodically distributed, and the bottom of the microstructure tips is fitted with the top of the bottom electrode.

[0012] Compared with the prior art, the utility model provides a new multifunctional flexible tactile sensor, which has the following beneficial effects:

[0013] 1. The new multifunctional flexible tactile sensor is provided with a flexible pad and a reinforcement. The flexible pad as a component for the middle connection can effectively enhance the structural stability between the flexible electrode and the flexible insulating layer. At the same time, the upper part of the flexible pad is fixed to the dome protrusion structure by adhesion, which can effectively prevent the sensor from causing performance problems or damage due to relative movement between layers during use. At the same time, the reinforcement can further reinforce the flexible electrode and the components at the bottom of the flexible electrode with the flexible substrate to improve the stability of the device and the stability between the material layers, which is conducive to improving the durability of the device.

[0014] 2. This new multifunctional flexible tactile sensor is equipped with a dome protrusion structure, a bottom electrode and a sub-signal channel. It is based on the piezoresistive effect or the piezoresistive effect, and adopts a five-channel electrode pattern design of a bottom electrode and a sub-signal channel. Combined with the unique design of the dome protrusion structure, the tactile force is conducted and amplified through the dome protrusion structure. Based on the differences in the responses of the five different sub-signal channels to external stimuli, such as peak value, shape, frequency, amplitude and interval, and with the help of the dome protrusion structure, the surface texture of the object can be recognized, so as to realize the same type of output signal, such as resistance or capacitance, so as to detect normal force, tangential force, tangential force direction, material softness, surface texture and other complex information in real time. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 This is a structural schematic diagram of a novel multifunctional flexible tactile sensor proposed in the utility model;

[0016] Figure 2 This is a schematic diagram of the three-dimensional structure explosion of a novel multifunctional flexible tactile sensor proposed in the utility model;

[0017] Figure 3 This is a schematic diagram of the bottom electrode of a novel multifunctional flexible tactile sensor proposed in the utility model;

[0018] Figure 4 A schematic diagram of the microstructure tip of a novel multifunctional flexible tactile sensor proposed in the utility model;

[0019] Figure 5 This is a normal force monitoring calibration diagram of a novel multifunctional flexible tactile sensor proposed in the utility model;

[0020] Figure 6 A schematic diagram of tangential force monitoring of a novel multifunctional flexible tactile sensor proposed in the utility model;

[0021] Figure 7 A schematic diagram of material softness monitoring of a novel multifunctional flexible tactile sensor proposed in the utility model;

[0022] Figure 8 This is a schematic diagram of material surface texture monitoring of a new type of multifunctional flexible tactile sensor proposed in the utility model.

[0023] In the figure: 1. Flexible substrate; 2. Flexible solid film; 3. Flexible pad film; 4. Flexible film; 5. Dome protrusion structure; 6. Bottom electrode; 7. Sub-signal channel; 8. Pressure sensing microstructure layer; 9. Flexible electrode; 10. Common electrode; 11. Flexible pad; 12. Reinforcement; 13. Flexible insulating layer; 14. Card interface; 15. Microstructure tip. DETAILED DESCRIPTION

[0024] The technical solutions in the embodiments of the present invention will be described clearly and completely below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all of the embodiments.

[0025] In the description of the present invention, it should be understood that the terms "upper", "lower", "front", "back", "left", "right", "top", "bottom", "inside", "outside", etc., indicating directions or positional relationships, are based on the directions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific direction, be constructed and operated in a specific direction, and therefore should not be understood as a limitation on the present invention.

[0026] Reference Figure 1-4 A novel multifunctional flexible tactile sensor comprises a flexible substrate 1, a bottom electrode 6 is coated on the top of the flexible substrate 1, the bottom electrode 6 is composed of five sub-electrodes, and the five sub-electrodes of the bottom electrode 6 are four arc-shaped electrodes surrounding a circular electrode in the middle, the five sub-electrodes of the bottom electrode 6 are connected to a corresponding sub-signal channel 7, the edge of the bottom electrode 6 is connected to the sub-signal channel 7 near the front, the top of the sub-signal channel 7 is covered with a flexible solid film 2, the flexible solid film 2 is attached to the top of the sub-signal channel 7, and is used to protect the sub-signal channel 7 to a certain extent, the top of the bottom electrode 6 is covered with a pressure sensing microstructure layer 8, a plurality of microstructure tips 15 are fixed to the bottom of the pressure sensing microstructure layer 8, the microstructure tips 15 are periodically distributed, the bottom of the microstructure tips 15 is attached to the top of the bottom electrode 6, the top of the pressure sensing microstructure layer 8 is provided with a flexible electrode 9, and the flexible electrode The front of 9 is connected to a common electrode 10, a flexible pad film 3 is provided at the bottom of the common electrode 10, a flexible insulating layer 13 is connected to the top of the flexible electrode 9, and the flexible electrode 9 and the common electrode 10 are printed on the bottom of the flexible insulating layer 13, a dome protrusion structure 5 is adhered to the top of the flexible insulating layer 13, the outer surface of the dome protrusion structure 5 is covered with a flexible film 4 near the edge, the bottom of the flexible film 4 is adhered to the top of the flexible substrate 1 near the edge of the bottom electrode 6, the inner side of the flexible film 4 is adhered to the outer surface of the dome protrusion structure 5, a flexible pad 11 is adhered to the top of the flexible insulating layer 13, the top of the flexible pad 11 is adhered to the dome protrusion structure 5, the flexible solid film 2 is located at the bottom of the flexible pad film 3, the edge of the flexible pad 11 is adhered to the reinforcement 12, a card interface 14 is provided on the flexible substrate 1, and the flexible substrate 1 is fixedly connected to the reinforcement 12 through the card interface 14.

[0027] Reference Figure 4-8 By continuously collecting and comparing the signals of the bottom electrode 6 and the flexible electrode 9, the integrated monitoring of the four target parameters of normal force, tangential force and its direction, softness and surface texture can be achieved.

[0028] like Figure 5 As shown, according to the following formula: Wherein ε is the dielectric constant between the electrodes, s is the relative area of ​​the two electrodes, and d is the inter-electrode distance. When performing normal force monitoring, a normal force ranging from 0 to 50N is gradually applied to the top of the sensor, and the relative capacitance changes between the central sub-electrode 3 of the bottom electrode 6 and the flexible electrode 9 are recorded in turn. According to the pattern in the figure, as the normal force increases, the relative capacitance continues to increase and gradually tends to saturation. This is because as the pressure in the pressure sensing microstructure layer increases, the space for the inter-electrode distance d to decrease gradually becomes smaller, so the calibration curve shows an upward trend from a high growth rate to saturation, which is in line with the expected effect described in the technical solution.

[0029] like Figure 6 As shown, when monitoring the tangential force, tangential forces were applied to the device in two directions, one to the right and the other 45° to the right and below, and the relative capacitance changes on the five sub-electrodes of the bottom electrode 6 were recorded respectively. It can be seen from the figure that when tangential forces in different directions are applied, there is always a slight increase in the relative capacitance of the central sub-electrode 3, and the relative capacitance of the sub-electrode farthest from the force application position along the tangential force direction always shows the largest increase, while the sub-electrode closest to the force application position along the tangential force direction always shows a slight decrease in relative capacitance. Such a change pattern is in line with the expected effect described in the technical solution.

[0030] like Figure 7 As shown in the figure, when monitoring the softness, the sponge (soft object) and the glass slide (hard object) were measured respectively, and the same normal force was applied to the dome protrusion structure above the device. The relative capacitance of each sub-electrode of the bottom electrode 6 was measured through the multi-channel signal acquisition module, and the ratio of the relative capacitance of the central electrode to the average relative capacitance of the four peripheral sub-electrodes was calculated. Figure 7 It includes the measured change trend of the relative capacitance of each channel of the sponge during the process of applying normal force and unloading and the related calculation results, and the measured change trend of the relative capacitance of each channel of the glass slide during the process of applying normal force and unloading and the related calculation results. According to the data and analysis in the figure, it can be seen that the calculated ratio of the sponge is smaller, indicating that the softness of the sponge is greater than that of the glass slide, proving that the softness of different target objects can be accurately judged through the above mechanism and calculation results.

[0031] like Figure 8 As shown, glasses with different surface textures (smooth glass, striped glass, and water-rippled glass) are used to slide across the dome protrusion structure of the device at the same speed, and the relative capacitance change between the flexible electrode 9 and the central sub-electrode 3 of the bottom electrode 6 is measured, and the surface texture is determined by the signal characteristics. According to the signal waveform, the relative capacitance of smooth glass remains basically stable during the sliding process due to its smooth surface; the dome protrusion structure of striped glass is subjected to periodic force during the sliding process due to the striped pattern on its surface, so the relative capacitance shows a quasi-periodic change; the dome protrusion structure of water-rippled glass is subjected to irregular mechanical stimulation during the sliding process due to the irregular and irregular water-rippled texture on its surface, so the relative capacitance shows a non-periodic and non-fixed pattern change effect.

[0032] Based on the above test results, the flexible tactile sensor can be used to monitor and sense the force characteristics and material structures of different targets to be tested. It can realize the continuous monitoring and perception of mechanical signals generated by various complex human activities, such as walking, jumping, massage, hand grasping objects, etc., and the material texture of target objects, such as oranges, durian, watermelons, etc., at specific parts, such as fingers, palms, soles of feet, knees, etc. Therefore, it will show broad application prospects in the fields of flexible smart wearables, health monitoring, etc.

[0033] In addition, the versatility and other characteristics of this flexible tactile sensor also enable it to be integrated or embedded in various special environments in different daily production and life scenarios to solve complex external mechanical stimuli. It has good application prospects and value, and also opens up new opportunities for the simple and cost-competitive manufacturing of new smart devices and wearable smart systems.

[0034] In the present invention, the bottom electrode 6 and the sub-signal channel 7 as well as the flexible electrode 9 and the common electrode 10 are obtained by uniformly coating the conductive material on the corresponding substrate surface and curing and molding, wherein the bottom electrode 6 and the sub-signal channel 7 are printed on the top of the flexible substrate 1, and the flexible electrode 9 and the common electrode 10 are at the bottom of the flexible insulating layer 13. The conductive material can be elastic carbon paste, conductive silver paste, carbon nanotubes, etc. The dome protrusion structure 5 and the pressure sensing microstructure layer 8 are obtained by injecting a flexible material precursor into a mold with a specific structure and finally curing and molding. The flexible material precursor can be a polyurethane precursor, a polydimethylsiloxane precursor, etc., and the flexible substrate 1 can be a polyurethane film, polydimethylsiloxane, polyester, etc. Materials, the flexible solid film 2 covers the sub-signal channel 7, and is mainly used to protect the sub-signal channel 7. At the same time, the top of the bottom electrode 6 is covered with a pressure sensing microstructure layer 8. The microstructure tip 15 at the bottom of the pressure sensing microstructure layer 8 can be a pyramid structure, a hemispherical structure, an irregular structure, etc., and is connected with a flexible pad 11 to ensure the stability of the connection between the flexible insulating layer 13 and the dome protrusion structure 5. At the same time, the reinforcement 12 is used to improve the stability of the bottom part of the dome protrusion structure 5. The flexible pad 11 can be bonded with a silicone adhesive to ensure flexibility while also being used for the stable conduction of external tactile force. The dome protrusion structure 5 is mainly used to conduct and amplify the applied external tactile force;

[0035] At the same time, this device can detect various complex information such as normal force, tangential force, tangential force direction, material softness, surface texture, etc. in real time;

[0036] When the normal force is applied, the signal change trends of all five sub-signal channels 7 are consistent. When the normal force is applied, the microstructure tip 15 on the pressure sensing microstructure layer 8 is flattened due to the force, the device as a whole is compressed, and the inter-electrode distance d between the bottom electrode 6 and the flexible electrode 9 is reduced. Figure 5 , according to the following formula: Where ε is the dielectric constant between the plates, s is the relative area of ​​the two plates, and d is the distance between the electrodes. It can be seen that when subjected to the normal force, the inter-electrode capacitance C value increases, and the degree of increase is determined by the magnitude of the normal force. During the test, the magnitude of the normal force can be measured by measuring the relative capacitance change between the electrode B and the sub-electrode 3 in the sub-signal channel 7;

[0037] When a tangential force is applied, the signal change trend of the sub-signal channel 7 perpendicular to the direction of action is similar. When the device is subjected to a tangential force, due to the transmission effect of the dome protrusion structure 5 on the force, the force on the pressure sensing microstructure layer 8 is closely related to the applied tangential force. The sub-electrode in the direction of the corresponding tangential force application and farthest from the force application position will be compressed to a greater extent than the sub-electrodes at other positions. Conversely, the sub-electrode close to the force application position in the direction of the corresponding tangential force application is subjected to a reaction force and tilted up, such as Figure 6 The above process causes the spacing values ​​d between the flexible electrode 9 and the five sub-electrodes of the bottom electrode 6 to be different. Therefore, by measuring the relative capacitances and the magnitude relationships between the flexible electrode 9 and the five sub-electrodes of the bottom electrode 6, the magnitude and direction of the applied tangential force can be determined.

[0038] When detecting the softness of an object, due to the structural design of the dome protrusion structure 5, objects with different hardnesses cause different stress concentrations on the dome protrusion structure 5, and the signal changes of the middle channel and the surrounding channels of the five sub-signal channels 7 are also different. When objects to be tested with different softnesses (different moduli) press the device with the same force, the surface of softer objects is easier to deform, while the surface of harder objects is not easy to deform. Based on this feature, the softness and hardness of the object can be judged by calculating the capacitance ratio. The specific sensing mechanism is as follows: objects to be tested with different softnesses (Young's modulus) are pressed against the top of the tactile sensor by applying the same normal force; for soft objects, due to their smaller Young's modulus, their surface deformation due to pressure is larger, and the deformation The region contacts the peripheral sub-electrode of the bottom electrode 6 and generates a certain peripheral pressure, so that among the five sub-electrodes of the bottom electrode 6, there is not only positive pressure above the central electrode 3, but also above the peripheral sub-electrodes 1, 2, 4, and 5. For hard objects, since the Young's modulus of the material itself is large and the deformation is small, most of the load is concentrated on the central electrode 3 of the bottom electrode 6, while the pressure of the peripheral sub-electrodes 1, 2, 4, and 5 is small. Therefore, by measuring the relative capacitance between the flexible electrode 9 and the central sub-electrode 3 and the relative capacitance between the flexible electrode 9 and the peripheral sub-electrodes 1, 2, 4, and 5, and calculating the ratio of the former to the average value of the latter, the softness of the object to be tested can be judged according to the results. The smaller the ratio, the softer it is, and the larger the ratio, the harder it is.

[0039] When detecting the surface texture of an object, the frequency and amplitude of the dynamic response signal also have large differences, so as to evaluate the surface texture and roughness of the object being scratched. Since the force stimulation modes of the dome protrusion structure 5 are different when objects with different surface textures slide on the surface of the device, the surface texture of the object to be tested is determined by measuring the change in the capacitance signal between the flexible electrode 9 and the central sub-electrode 3 of the bottom electrode 6. The specific sensing mechanism is as follows: the object to be tested with different surface textures is scratched across the surface of the device at the same sliding speed. Since the dome protrusion structure 5 is subjected to different loads, swing amplitudes and movement cycles when being scratched by objects with different textures, the inter-electrode spacing between the flexible electrode 9 and the central sub-electrode 3 of the bottom electrode 6 changes with the movement mode of the protrusion structure, which in turn causes the capacitance signal between the two to fluctuate characteristically. The surface texture of the sample can be determined by monitoring the above capacitance signal change characteristics between the two.

[0040] Through the above sensing mechanism, a variety of complex information such as normal force, tangential force, tangential force direction, material softness, surface texture, etc. can be detected in real time based on a tactile sensor;

[0041] In addition, the flexible tactile sensor uses the same type of electrical signal output, namely capacitance signal or resistance signal, which makes up for the incompatibility of multiple signals in traditional multifunctional tactile sensor devices, avoids the switching / conversion process back and forth between different signal acquisition devices, and greatly improves the efficiency of signal acquisition and tactile information analysis.

[0042] The above are only preferred specific implementation methods of the utility model, but the protection scope of the utility model is not limited to this. Any technician familiar with the technical field within the technical scope disclosed by the utility model, who makes equivalent replacements or changes based on the technical scheme and utility model concept of the utility model, should be covered by the protection scope of the utility model.

Claims

1. A novel multifunctional flexible tactile sensor, comprising a flexible substrate (1), characterized in that: The top of the flexible substrate (1) is coated with a bottom electrode (6), the edge of the bottom electrode (6) is connected to a sub-signal channel (7) near the front, the top of the sub-signal channel (7) is covered with a flexible solid film (2), the top of the bottom electrode (6) is covered with a pressure sensing microstructure layer (8), the top of the pressure sensing microstructure layer (8) is provided with a flexible electrode (9), the front of the flexible electrode (9) is connected to a common electrode (10), the bottom of the common electrode (10) is provided with a flexible pad film (3), the top of the flexible electrode (9) is connected to a flexible insulating layer (13), and the flexible electrode (9) and the common electrode (10) are printed on the bottom of the flexible insulating layer (13), the top of the flexible insulating layer (13) is adhered with a dome protrusion structure (5), and the outer surface of the dome protrusion structure (5) is covered with a flexible film (4) near the edge.

2. A novel multifunctional flexible tactile sensor according to claim 1, characterized in that: A flexible pad (11) is adhered to the top of the flexible insulating layer (13), a reinforcing member (12) is adhered to the edge of the flexible pad (11), a card interface (14) is provided on the flexible substrate (1), and the flexible substrate (1) is fixedly connected to the reinforcing member (12) via the card interface (14).

3. A novel multifunctional flexible tactile sensor according to claim 2, characterized in that: The top of the flexible pad (11) is bonded to the dome protrusion structure (5), and the flexible solid film (2) is located at the bottom of the flexible pad film (3).

4. A novel multifunctional flexible tactile sensor according to claim 1, characterized in that: The bottom of the flexible film (4) is bonded to the top of the flexible substrate (1) near the edge of the bottom electrode (6), and the inner side of the flexible film (4) is bonded to the outer surface of the dome protrusion structure (5).

5. The novel multifunctional flexible tactile sensor according to claim 1 is characterized in that: The bottom electrode (6) is composed of five sub-electrodes, and the five sub-electrodes of the bottom electrode (6) present four arc-shaped electrodes surrounding a circular electrode in the middle, and the five sub-electrodes of the bottom electrode (6) are all connected to a corresponding sub-signal channel (7).

6. The novel multifunctional flexible tactile sensor according to claim 1 is characterized in that: A plurality of microstructure tips (15) are fixed to the bottom of the pressure sensing microstructure layer (8), the microstructure tips (15) are distributed periodically, and the bottom of the microstructure tips (15) is fitted to the top of the bottom electrode (6).

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