Pressure-temperature dual-mode sensor and preparation method and application thereof

Abstract

According to the pressure-temperature dual-mode sensor and the preparation method and application thereof provided by the invention, the pressure sensing layer is designed into the gradient inclined magnetic column array which is distributed in a rectangular array, and the gradient inclined magnetic column array has the layout characteristics of gradient change and inclination of the length, the position and the like of the magnetic columns; a special magnetic field gradient can be created in the space, and the magnetic field gradient can enable the pressure-temperature dual-mode sensor to generate linear or relatively uniform change response to external stimuli with different magnitudes, so that the measuring range of pressure testing can be widened; the problems of inaccurate measurement and small measurement range caused by the stress concentration problem of other microstructures and the large structure overlapping phenomenon are effectively solved. And meanwhile, the pressure sensing layer and the temperature sensing layer are tested in a layered manner, so that the problem of mutual crosstalk of a temperature signal and a pressure signal is avoided, and the detection accuracy and precision of the pressure-temperature dual-mode sensor are further improved.

Description

Technical Field

[0001] The present invention relates to the technical field of flexible sensors, and in particular to a pressure-temperature dual-mode sensor and a preparation method and application thereof. Background Art

[0002] In the existing flexible pressure sensor manufacturing technology, in order to obtain high-sensitivity and wide-range sensors, it is usually necessary to combine soft materials with different elastic moduli during the manufacturing process, so as to ensure high sensitivity and expand the wide range. At the same time, in order to cope with complex physical environments, multiple signals must be processed simultaneously. Many multi-mode sensors leave multi-signal processing to the back-end circuit and algorithm processing, which will seriously increase the complexity of the back-end work. The traditional multi-mode sensors that superimpose multiple materials have more or less signal interference.

[0003] However, this flexible thin film sensor with multiple sensitive materials stacked on top of each other has the following problems: first, it will greatly increase the volume of the sensor and affect the flexibility and assembly of the thin film material; second, it will be difficult to control the ratio of each material in this multi-material sensor, resulting in different performance of the sensors and poor product uniformity; third, there are other pressure sensors with surface microstructures (cones, prisms, cylinders, etc.), but this inevitably leads to stress concentration, the microstructure part is always subject to the greatest force, and larger microstructures overlap; fourth, multi-mode sensors have signal interference problems, which greatly affects sensor performance.

[0004] Therefore, there is an urgent need for a pressure-temperature dual-mode sensor and a preparation method and application thereof to solve the above-mentioned technical problems. Summary of the invention

[0005] The purpose of the present invention is to provide a pressure-temperature dual-mode sensor and a preparation method and application thereof, so as to solve the technical problems of the existing pressure-temperature dual-mode sensor that the pressure test range is too small and the test accuracy is too low.

[0006] In order to solve the above technical problems, the present invention first provides a pressure-temperature dual-mode sensor, comprising a base layer, a flexible micro-nano coil assembly, an adhesive layer and a temperature sensing layer stacked in sequence, wherein a pressure sensing layer is arranged on a surface of the temperature sensing layer away from the base layer, and the pressure sensing layer is a gradient inclined magnetic column array distributed in a rectangular array; The gradient inclined magnetic column array has a plurality of magnetic column groups spaced apart along a first direction, each magnetic column group includes a plurality of magnetic columns spaced apart and having different lengths along a second direction, and the second direction is perpendicular to the first direction; the lengths of the plurality of magnetic columns in each magnetic column group gradually increase or decrease along the second direction.

[0007] Preferably, the inclination angles of the plurality of magnetic pillars and the plane where the temperature sensing layer is located are equal, and the inclination angle is greater than or equal to 15° and less than or equal to 55°.

[0008] Preferably, the bottom diameter of the magnetic column is 0.5 mm to 1.5 mm; the distance between two adjacent magnetic columns is 0.5 mm to 1.5 mm; and the length of the magnetic column is 0.5 mm to 3.5 mm.

[0009] Preferably, the material of the base layer is soft silicone; and the material of the adhesive layer is silicone-type adhesive.

[0010] Preferably, along the direction from the base layer to the temperature sensing layer, the flexible micro-nano coil assembly includes a coil base, a first micro-nano coil layer, an intermediate insulating layer, a second micro-nano coil layer and a coil packaging layer which are stacked in sequence; The coil substrate and the coil packaging layer are made of polyimide, and the middle insulating layer is made of insulating polymer. Preferably, the first micro-nano coil layer is connected to a first electrode, and the second micro-nano coil layer is connected to a second electrode, and the first electrode and the second electrode are used to connect an external pressure measurement signal for pressure testing; the temperature sensing layer is connected to a third electrode and a fourth electrode, and the third electrode and the fourth electrode are used to connect an external temperature measurement signal for temperature testing.

[0011] Preferably, the temperature sensing layer is prepared by squeezing a temperature-sensitive solution consisting of a mixture of a temperature-sensitive material and soft silicone into a mold via a syringe; the temperature-sensitive material includes any one of vanadium oxide, Pedot:pss and graphene.

[0012] Preferably, the pressure sensing layer is prepared by pouring a magnetic solution consisting of a mixture of magnetic powder particles and soft silica gel into a 3D printing mold and then performing inverted molding; the mass fraction of the magnetic powder particles in the magnetic solution is 10% to 90%; and the magnetic powder particles are neodymium iron boron magnetic powder.

[0013] Accordingly, the present invention further provides a method for preparing a pressure-temperature dual-mode sensor as described in any one of the above items, the method comprising: S1, preparing a flexible micro-nano coil assembly on a substrate layer; S2, bonding the temperature sensing layer to the flexible micro-nano coil assembly through an adhesive layer; S3, forming a gradient tilted magnetic column array distributed in a rectangular array on the temperature sensing layer to obtain a pressure-temperature dual-mode sensor.

[0014] Correspondingly, the present invention further provides an application of a pressure-temperature dual-mode sensor as described above or a pressure-temperature dual-mode sensor prepared by the preparation method as described above in robots and wearable electronic products.

[0015] The beneficial effect of the present invention is as follows: Different from the prior art, the present invention provides a pressure-temperature dual-mode sensor and its preparation method and application. The pressure-temperature dual-mode sensor designs the pressure sensing layer as a gradient tilted magnetic column array distributed in a rectangular array. The gradient tilted magnetic column array will create a special magnetic field gradient in space due to the gradient change and tilted layout characteristics of the length and position of the magnetic columns. When the pressure-temperature dual-mode sensor is working, when the external pressure acts on the pressure-temperature dual-mode sensor, this magnetic field gradient can make the pressure-temperature dual-mode sensor produce a linear or relatively uniform response to external stimuli of different sizes, and this response will show a regular change trend that matches the pressure size according to the magnetic field gradient, while eliminating the overlap between the magnetic columns, allowing the pressure-temperature dual-mode sensor to output accurate signals corresponding to the pressure within a wider pressure range, thereby broadening the range of pressure testing, and effectively solving the problems of stress concentration in other microstructures and uncertainty and small measurement range caused by the overlap of large structures. At the same time, the pressure sensing layer and the temperature sensing layer are tested in layers to avoid the problem of crosstalk between temperature signals and pressure signals, further improving the detection accuracy and precision of the pressure-temperature dual-mode sensor. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 A schematic diagram of the structure of a pressure-temperature dual-mode sensor provided in Example 1 of the present invention; Figure 2 An exploded schematic diagram of the pressure-temperature dual-mode sensor provided in Example 1 of the present invention; Figure 3 A schematic diagram of the connection between the gradient tilted magnetic column array and the temperature sensing layer in the pressure-temperature dual-mode sensor provided in Example 1 of the present invention; Figure 4 A process flow chart of a method for preparing a pressure-temperature dual-mode sensor provided in Example 1 of the present invention; In the accompanying drawings: 100-pressure-temperature dual-mode sensor; 10-base layer; 20-flexible micro-nano coil assembly; 21-coil base; 22-first micro-nano coil layer; 23-intermediate insulating layer; 24-second micro-nano coil layer; 25-coil packaging layer; 30-adhesive layer; 40-temperature sensing layer; 50-pressure sensing layer; 51-magnetic column. DETAILED DESCRIPTION

[0017] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0018] The purpose of the present invention is to provide a pressure-temperature dual-mode sensor 100 and a preparation method and application thereof, so as to solve the technical problems of the existing pressure-temperature dual-mode sensor 100 that the pressure test range is too small and the test accuracy is too low.

[0019] The present application scheme is now further described in conjunction with specific embodiments.

[0020] Embodiment 1: See also Figures 1 to 3 Embodiment 1 of the present invention first provides a pressure-temperature dual-mode sensor 100, comprising a base layer 10, a flexible micro-nano coil assembly 20, an adhesive layer 30 and a temperature sensing layer 40 stacked in sequence, a pressure sensing layer 50 is disposed on a surface of the temperature sensing layer 40 away from the base layer 10, and the pressure sensing layer 50 is a gradient inclined magnetic column array distributed in a rectangular array; The gradient tilted magnetic column array comprises a plurality of magnetic column groups spaced apart along a first direction D1, each magnetic column group comprises a plurality of magnetic columns 51 spaced apart and having different lengths along a second direction D2, the second direction D2 is perpendicular to the first direction D1; and the lengths of the plurality of magnetic columns 51 in each magnetic column group gradually decrease along the second direction D2.

[0021] In Example 1 of the present invention, the pressure-temperature dual-mode sensor 100 presents a clear stacked structure from bottom to top, which is sequentially composed of a base layer 10, a flexible micro-nano coil assembly 20, an adhesive layer 30, and a temperature sensing layer 40, and a pressure sensing layer 50 is further provided on the temperature sensing layer 40. This layered arrangement enables each part to have its specific function, and cooperate with each other to realize dual-mode measurement of pressure and temperature.

[0022] Specifically, the base layer 10 serves as the bottommost support structure, providing certain stability and basic physical properties for the entire pressure-temperature dual-mode sensor 100; wherein, the material of the base layer 10 is preferably soft silicone; soft silicone is selected as the material, and soft silicone has good flexibility, deformability and certain elasticity, and can adapt to different usage environments and the surface shape of the object being measured, while providing a stable attachment basis for the upper layers, thereby preventing the overall structure of the pressure-temperature dual-mode sensor 100 from being easily damaged.

[0023] In Embodiment 1 of the present invention, along the direction from the base layer 10 to the temperature sensing layer 40, the flexible micro-nano coil assembly 20 includes a coil base 21, a first micro-nano coil layer 22, an intermediate insulating layer 23, a second micro-nano coil layer 24 and a coil packaging layer 25 which are stacked in sequence; The coil substrate 21 and the coil packaging layer 25 are made of polyimide, the middle insulating layer 23 is made of insulating polymer; the first micro-nano coil layer 22 and the second micro-nano coil layer 24 are both MEMS (Micro-Electro-Mechanical Systems) coils.

[0024] Specifically, in addition to providing physical support, the coil substrate 21 can also affect the thermal conductivity, electrical insulation and other properties of the entire flexible micro-nano coil assembly 20 to a certain extent. Its flat surface provides a good foundation for the subsequent production and attachment of the first micro-nano coil layer 22, ensuring that the first micro-nano coil layer 22 can be laid evenly and stably on it, which is conducive to achieving precise electromagnetic characteristics.

[0025] Specifically, the core function of the intermediate insulating layer 23 is to provide insulation isolation between the first micro-nano coil layer 22 and the second micro-nano coil layer 24, and can perform electrical connection and signal transmission respectively according to actual needs, thereby providing a guarantee for realizing more complex and precise electromagnetic functions.

[0026] Specifically, the coil encapsulation layer 25 acts as a "protective shell", encapsulating the entire flexible micro-nano coil assembly 20, so that the assembly can operate normally in different usage environments, whether it is a relatively harsh industrial environment or a special environment such as the human body, reducing the interference and damage to its performance caused by external factors.

[0027] Specifically, the first micro-nano coil layer 22 and the second micro-nano coil layer 24 are MEMS coils, which are at the micro-nano level, usually in the micrometer or even nanometer range, so that they can realize electromagnetic induction and other functions in a very small space, and are very suitable for integration into such a flexible micro-nano coil assembly 20 to meet the development needs of miniaturization and integration. They also have the characteristics of high sensitivity, and can keenly sense and produce corresponding electromagnetic induction changes for subtle changes in physical quantities such as external magnetic fields. For example, in magnetic field detection applications, they can accurately capture weak magnetic field fluctuations and convert them into electrical signal outputs, which is very critical for high-precision measurement and detection applications.

[0028] Furthermore, the first micro-nano coil layer 22 and the second micro-nano coil layer 24 are made in a mirror-symmetrical manner, and the purpose of such production is to increase the output power of the pressure test signal of the pressure-temperature dual-mode sensor 100. Preferably, the flexible micro-nano coil assembly 20 can also select a single-layer multi-turn micro-nano coil, but a single-layer multi-turn micro-nano coil may cause the output power of the pressure test signal of the pressure-temperature dual-mode sensor 100 to be too low, and the back-end circuit detection is difficult. Therefore, it is recommended that the number of micro-nano coil layers in the flexible micro-nano coil assembly 20 is greater than or equal to 2 layers. Furthermore, when cooperating with the external gradient tilted magnetic column array, the first micro-nano coil layer 22 and the second micro-nano coil layer 24 can jointly sense the magnetic field changes caused by pressure changes, convert the magnetic field changes into electrical signals, and then realize functions such as pressure measurement, and compared with a single-layer MEMS coil, this double-layer setting can often improve the accuracy and reliability of measurement.

[0029] In Example 1 of the present invention, the bonding layer 30 uses a silicone adhesive. This material can effectively bond the flexible micro-nano coil assembly 20 and the temperature sensing layer 40 together. It has good bonding performance. Moreover, since it is also a silicone material, it has good compatibility with the adjacent soft silicone base layer 10 in chemical and physical properties, thereby ensuring the stability of the connection between the layers and the overall sealing of the sensor.

[0030] In Example 1 of the present invention, the temperature sensing layer 40 is prepared by squeezing a temperature-sensitive solution consisting of a mixture of a temperature-sensitive material and soft silicone into a mold via a syringe; the temperature-sensitive material includes any one of vanadium oxide, Pedot:pss (a composite of poly 3,4-ethylenedioxythiophene and poly 4-styrene sulfonate) and graphene, and Pedot:pss is preferably used in Example 1 of the present invention.

[0031] Specifically, the temperature sensing layer 40 is connected to a third electrode and a fourth electrode, and the third electrode and the fourth electrode are used for externally connecting a temperature measurement signal to perform a temperature test.

[0032] Furthermore, the principle of the temperature test performed by the pressure-temperature dual-mode sensor 100 provided by the present invention using the temperature sensing layer 40 is as follows: The sensing mechanism of the temperature sensing layer 40 includes the contact resistance of the third electrode and the fourth electrode and the body resistance of the temperature sensing layer 40. When the temperature changes, the resistance of the temperature-sensitive material changes, causing the body resistance of the temperature sensing layer 40 to change. Since the temperature sensing layer 40 is connected to the third electrode / fourth electrode, the contact resistance between the two layers remains stable. Therefore, when an external force is applied to the temperature sensing layer 40, the pressure has little effect on the body resistance and contact resistance of the temperature sensing layer 40. The temperature sensing layer 40 does not respond to external pressure but only responds to temperature changes.

[0033] In Embodiment 1 of the present invention, a pressure sensing layer 50 is disposed on a surface of the temperature sensing layer 40 away from the base layer 10 , and the pressure sensing layer 50 is a gradient inclined magnetic column array distributed in a rectangular array; The gradient-inclined magnetic column array includes a plurality of magnetic column groups spaced apart along a first direction D1, each magnetic column group includes a plurality of magnetic columns 51 spaced apart and having different lengths along a second direction D2, and the second direction D2 is perpendicular to the first direction D1; the lengths of the plurality of magnetic columns 51 in each magnetic column group decrease gradually along the second direction D2.

[0034] Specifically, the principle of the pressure-temperature dual-mode sensor 100 provided by the present invention using the pressure sensing layer 50 and the flexible micro-nano coil assembly 20 to perform pressure testing in collaboration is as follows: The pressure sensing layer 50 adopts a gradient tilted magnetic column array distributed in a rectangular array, which includes a plurality of magnetic column groups spaced apart along a first direction D1, and each magnetic column group has a plurality of magnetic columns 51 spaced apart and with a gradient decreasing length along a second direction D2 (perpendicular to the first direction D1), and the magnetic columns 51 also have a specific tilt angle with the plane where the temperature sensing layer 40 is located. When external pressure is applied to the pressure sensing layer 50, the magnetic columns 51 will be subjected to stress, and the internal magnetic domain structure will change due to the stress, so that the magnetic parameters such as the magnetic permeability and magnetic moment of the magnetic columns 51 will change, thereby changing the magnetic field generated by themselves. Moreover, the magnetic columns 51 at different positions, lengths and tilt angles are subjected to different pressures and different changes in the magnetic field generated. For example, the magnetic columns 51 at the edge of the array and the magnetic columns 51 at the center will have different changes in the magnetic field due to the difference in the force conditions.

[0035] When the magnetic field of the magnetic column 51 of the pressure sensing layer 50 changes due to pressure, the magnetic flux passing through the MEMS coil (the first micro-nano coil layer 22 and the second micro-nano coil layer 24) in the flexible micro-nano coil assembly 20 will change accordingly. According to Faraday's law of electromagnetic induction, when the magnetic flux passing through the closed coil changes, an induced electromotive force will be generated at both ends of the coil.

[0036] The magnetic field gradient formed by the gradient-tilted magnetic column array of the pressure sensing layer 50 enables the magnetic field changes of the magnetic columns 51 at different positions to complement and cooperate with each other when the pressure changes. Even a slight pressure change can be reflected as a perceptible difference in the magnetic flux and induced electromotive force of the flexible micro-nano coil assembly 20, thereby improving the resolution and accuracy of pressure measurement, avoiding the situation where small pressure changes cannot be accurately captured due to uniform and indifferent magnetic fields, and achieving accurate measurement of pressure values ​​over a wide range.

[0037] Furthermore, the first micro-nano coil layer 22 is connected to a first electrode, and the second micro-nano coil layer 24 is connected to a second electrode. These electrodes are used to connect to an external pressure measurement signal, and can conveniently collect the generated induced electromotive force, which is an electrical signal, and transmit it to a subsequent measurement circuit or processing device. By analyzing, calibrating, and performing related conversion operations on the collected electrical signal, the size of the externally applied pressure can be inferred based on the corresponding relationship between the electrical signal and the pressure, and finally the pressure test function is realized, completing the collaborative pressure measurement process of the pressure sensing layer 50 and the flexible micro-nano coil assembly 20.

[0038] In Example 1 of the present invention, the test pressure part in the pressure-temperature dual-mode sensor 100 is a self-powered sensor and does not require external power supply, so there is no energy consumption; the test temperature part in the pressure-temperature dual-mode sensor 100 is a piezoresistive sensor that relies on resistance changes and requires external power supply.

[0039] Specifically, the pressure sensing layer 50 is prepared by a 3D printing process using a magnetic solution consisting of a mixture of magnetic powder particles and soft silica gel; the mass fraction of the magnetic powder particles in the magnetic solution is 10% to 90%, preferably 70%; and the magnetic powder particles are preferably neodymium iron boron magnetic powder.

[0040] Furthermore, NdFeB is selected as the material of magnetic powder particles because it is a high-performance permanent magnetic material. It has high remanence, coercive force and large maximum magnetic energy product. Remanence means that when the external magnetic field is removed, the material itself can still retain strong magnetism, which enables the pressure sensing layer 50 to maintain a relatively stable and strong magnetic field environment without continuous excitation of the external magnetic field, and can create a magnetic field of sufficient strength for the pressure sensing layer 50. In subsequent pressure measurements, based on this strong magnetic foundation, obvious magnetic field changes can be generated to be detected.

[0041] Furthermore, when the mass fraction of magnetic powder particles is less than 10%, although the fluidity of the entire magnetic solution is relatively good, which is convenient for subsequent 3D printing operations, and the pressure sensing layer 50 is more flexible and can better adapt to the surfaces of objects of various shapes and some use scenarios with deformation requirements, the magnetic powder is relatively small, and the magnetic field strength generated is relatively weak. When subjected to pressure, the change amplitude of the magnetic field may be small, which will affect the sensitivity of pressure measurement to a certain extent, and may only detect relatively large pressure changes to produce recognizable signal changes. As the mass fraction of magnetic powder particles increases, approaching 70%, the magnetic field strength will be significantly enhanced, and the magnetic field change will be more obvious under pressure, which is conducive to improving the accuracy of pressure measurement and the minimum detectable pressure change value, that is, improving sensitivity. However, too high a magnetic powder content (greater than 70%) will cause the fluidity of the magnetic solution to deteriorate, making it more difficult to extrude the material from the nozzle during 3D printing, and may cause nozzle clogging, etc., and the flexibility of the pressure sensing layer 50 produced will be reduced, becoming relatively brittle, and easily ruptured when subjected to external forces, affecting its service life and applicability.

[0042] Specifically, the inclination angles of the multiple magnetic columns 51 and the plane where the temperature sensing layer 40 is located are equal, and the inclination angle is greater than or equal to 15° and less than or equal to 55°; wherein, when the magnetic column 51 is inclined, the direction of the magnetic field it generates is no longer simply perpendicular or parallel to a certain plane, but forms a specific inclined direction in space. For example, compared with the magnetic column 51 placed perpendicular to the plane, the magnetic field lines generated by the inclined magnetic column 51 will extend and bend along the inclined direction in space. The multiple magnetic columns 51 are arranged at the same inclination angle, and their magnetic fields overlap and influence each other, thereby forming a complex and regular magnetic field distribution pattern around and above the entire pressure sensing layer 50. This distribution plays a key role in the subsequent realization of the pressure measurement function.

[0043] Furthermore, when the tilt angle is less than 20°, the magnetic column 51 is too close to the plane where the temperature sensing layer 40 is located, the magnetic flux change is too small, the output pressure signal of the pressure-temperature dual-mode sensor 100 is too small, and the output cannot be detected. At the same time, it will cause the magnetic column to compress and overlap, thereby reducing the accuracy and precision of pressure measurement; when the tilt angle is greater than 40°, the magnetic column 51 is too far away from the MEMS coil, and the upward bending angle of the magnetic column 51 is too small, the output pressure signal of the pressure-temperature dual-mode sensor 100 is too small, and the output cannot be detected. Therefore, combined with the structural parameters of the magnetic column 51 and the output parameters of the pressure-temperature dual-mode sensor 100, under the existing device parameters, the embodiment 1 of the present invention determines that when the tilt angle is 35°, the two distinguishable signals generated by the bidirectional bending of the pressure-temperature dual-mode sensor 100 are the best.

[0044] Specifically, the distance between two adjacent magnetic pillars 51 is 0.5 mm to 1.5 mm, preferably 1 mm; when the distance between two adjacent magnetic pillars 51 is too large, the entire device becomes too large and inconvenient to use. When the distance between two adjacent magnetic pillars 51 is too small, the magnetic pillars 51 are prone to cross-overlap during the bending process, and the magnetic flux change is too small, both of which result in the output pressure signal of the pressure-temperature dual-mode sensor 100 being too small.

[0045] Specifically, the bottom diameter of the magnetic column 51 is 0.5 mm to 1.5 mm, preferably 1 mm; the length of the magnetic column 51 is 0.5 mm to 3.5 mm.

[0046] Furthermore, when the bottom diameter is smaller, such as when it is close to 0.5 mm, the magnetic field generated by the magnetic column 51 is relatively more concentrated in a smaller area around it, and the change of the magnetic field in space will be "steeper", that is, the magnetic field gradient is more obvious, which is conducive to improving the resolution of the pressure-temperature dual-mode sensor 100 for small pressure changes and can more accurately sense the subtle fluctuations of pressure. The magnetic field distribution generated by the magnetic column 51 with a larger bottom diameter is relatively flatter and more uniform. Under the action of greater pressure or when a larger range of pressure changes needs to be detected, its stable magnetic field characteristics can ensure that the overall magnetic field change is still within the range that can be accurately detected and analyzed, which helps to broaden the range of pressure measurement. Therefore, a reasonable choice of the bottom diameter size can balance the magnetic field uniformity and gradient to meet different pressure measurement requirements.

[0047] Furthermore, as the length of the magnetic column 51 increases, the distribution of its internal magnetic domains and the strength of the magnetic field generated to the outside will also change. Generally speaking, within a certain range, the longer the length, the stronger the magnetic field may be, but at the same time, the gradient of the change in magnetic field strength along the length direction will be more complex. For example, under pressure, the difference in magnetic field changes at different length positions will be more significant, which provides more detailed information for accurately measuring pressure by detecting magnetic field changes, and helps to improve the accuracy and resolution of measurements, especially for the detection of small pressure changes. For shorter magnetic columns 51, the change in magnetic field strength is relatively simple and direct, which may be more suitable in some application scenarios where the measurement accuracy requirements are not particularly high and more emphasis is placed on overall stability and simple response relationships.

[0048] Accordingly, see Figures 1 to 4 Embodiment 1 of the present invention further provides a method for preparing a pressure-temperature dual-mode sensor 100 as described above, which realizes a flexible sensor that satisfies both high sensitivity and wide range by designing a gradient tilted magnetic column array, and specifically comprises the following steps: S10, preparing a flexible micro-nano coil assembly 20 on the base layer 10.

[0049] Specifically, step S10 also includes: A flexible micro-nano coil assembly 20 is prepared on the base layer 10. The flexible micro-nano coil assembly 20 includes a coil base 21, a first micro-nano coil layer 22, an intermediate insulating layer 23, a second micro-nano coil layer 24 and a coil packaging layer 25 which are stacked in sequence from bottom to top; wherein the high-density flexible micro-nano coil assembly 20 is prepared by photolithography, etching, electroplating and other methods. For specific methods, see Chinese invention patent ZL202311264390.9. The key dimensions, number of turns and number of layers of the MEMS coil can be designed according to the actual needs of signal output and the accuracy of process equipment, which will not be repeated here.

[0050] S20 , bonding the temperature sensing layer 40 to the flexible micro-nano coil assembly 20 through the bonding layer 30 .

[0051] Specifically, step S20 also includes: First, a temperature-sensitive solution obtained by mixing a temperature-sensitive material and soft silicone is poured into a mold to prepare a temperature sensing layer 40 ; then, the temperature sensing layer 40 is bonded to the flexible micro-nano coil assembly 20 through the bonding layer 30 .

[0052] Furthermore, the temperature-sensitive material can be selected from materials with temperature stability, such as vanadium oxide, Pedot:pss, graphene, etc. The temperature-sensitive material and soft silica gel can be mixed into a temperature-sensitive solution by a spin coating method or a spraying method. The specific thickness of the temperature sensing layer 40 is made according to the design of the pressure-temperature dual-mode sensor 100.

[0053] S30 , forming a gradient-inclined magnetic column array distributed in a rectangular array on the temperature sensing layer 40 to obtain a pressure-temperature dual-mode sensor 100 .

[0054] Specifically, step S30 also includes: First, the corresponding gradient tilted magnetic column array area is designed according to the size of the flexible micro-nano coil assembly 20 designed in advance in step S20, and the corresponding gradient structure 3D printing mold is prepared by the 3D printing molding method; then, the magnetic solution mixed with magnetic powder particles and soft silicone is squeezed into the gradient structure 3D printing mold through a syringe to prepare a gradient tilted magnetic column array distributed in a rectangular array; finally, the prepared gradient tilted magnetic column array is assembled with the temperature sensing layer 40 to finally obtain the pressure-temperature dual-mode sensor 100.

[0055] Specifically, the length and tilt angle of the gradient tilted magnetic column array were found through experimental exploration: the tilted magnetic column cannot be designed to be too long, otherwise it will easily tilt and fall to the ground and easily cross-contact with other magnetic columns; the tilted magnetic column cannot be designed to be too short, otherwise the magnetic flux passing through the MEMS coil will be insufficient.

[0056] In this step, the overall size of the gradient tilted magnetic column array is 1cm×1cm. Through experimental exploration, the specific size of the tilted gradient magnetic column array is as follows: the gradient tilted magnetic column array is composed of 4×4, in which the bottom diameter of the magnetic column 51 is 1mm; the lengths of the multiple magnetic columns 51 in each magnetic column group along the second direction D2 are 3.5mm, 2.5mm, 1.5mm, and 0.5mm respectively, and the tilt angle of each magnetic column 51 to the temperature sensing layer 40 is 35°; the distance between two adjacent magnetic columns 51 is 1mm.

[0057] The present invention provides a gradient tilted magnetic column array that compensates for the contact area during the sequential contact of the magnetic columns 51 from high to low, thereby achieving a wide range of design requirements. The high uniformity between the pressure-temperature dual-mode sensors 100 comes from the excellent batch-to-batch consistency of the gradient structure mold prepared by the manufacturing process based on 3D printing. When the magnetic column 51 of the top gradient tilted magnetic column array is stimulated externally, the magnetic flux of the magnetic column 51 close to the MEMS coil increases successively, which is the main reason for the increase in induced electromotive force when the pressure tactile sensor measures the pressure value. At the same time, the temperature sensitive layer changes its resistance value through the temperature sensitive material under the change of temperature, and a separate lead is used for measurement, avoiding interference with the pressure measurement signal.

[0058] Different from the prior art, the present invention has the following beneficial effects: 1. Expanding the pressure test range of the pressure-temperature dual-mode sensor 100: The present invention designs the pressure sensing layer 50 into a gradient tilted magnetic column array, so that the pressure-temperature dual-mode sensor 100 can be tested over a wide range, effectively solving the stress concentration problem in other pressure sensing microstructures and the problem of uncertainty and small measurement range caused by large structure overlap. As the size of the external stimulus changes, the output signal gradually increases.

[0059] 2. Accurate measurement of multiple signals of multi-mode sensors: Due to the superposition of different sensitive layers, existing sensors require external electrodes to measure signals, which leads to signal interference and cumbersome preparation processes. At the same time, special back-end circuits and algorithms are required for data processing. The present invention reduces signal crosstalk, improves sensor signal accuracy, and reduces unnecessary steps in back-end work by measuring the temperature sensing layer 40 and the pressure sensing layer 50 in layers.

[0060] It should be noted that the above embodiments all belong to the same inventive concept, and the description of each embodiment has its own focus. For matters that are not described in detail in some embodiments, reference may be made to the description in other embodiments.

[0061] The above embodiments only express the implementation methods of the present invention, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the invention patent. It should be pointed out that, for those of ordinary skill in the art, several variations and improvements can be made without departing from the concept of the present invention, and these all belong to the protection scope of the present invention. Therefore, the protection scope of the patent of the present invention shall be subject to the attached claims.

Claims

1. A pressure-temperature dual-mode sensor, characterized in that: It comprises a base layer, a flexible micro-nano coil assembly, an adhesive layer and a temperature sensing layer which are stacked in sequence, wherein a pressure sensing layer is arranged on a surface of the temperature sensing layer away from the base layer, and the pressure sensing layer is a gradient inclined magnetic column array distributed in a rectangular array; The gradient inclined magnetic column array comprises a plurality of magnetic column groups spaced apart along a first direction, each of the magnetic column groups comprises a plurality of magnetic columns spaced apart and having different lengths along a second direction, the second direction being perpendicular to the first direction; and the lengths of the plurality of magnetic columns in each of the magnetic column groups gradually increase or decrease along the second direction.

2. The pressure-temperature dual-mode sensor according to claim 1, characterized in that: The inclination angles of the plurality of magnetic pillars and the plane where the temperature sensing layer is located are equal, and the inclination angle is greater than or equal to 15° and less than or equal to 55°.

3. The pressure-temperature dual-mode sensor according to claim 1, characterized in that: The bottom diameter of the magnetic column is 0.5 mm to 1.5 mm; the distance between two adjacent magnetic columns is 0.5 mm to 1.5 mm; and the length of the magnetic column is 0.5 mm to 3.5 mm.

4. The pressure-temperature dual-mode sensor according to claim 1, characterized in that: The material of the base layer is soft silicone; the material of the adhesive layer is silicone-type adhesive.

5. The pressure-temperature dual-mode sensor according to claim 1, characterized in that: Along the direction from the base layer to the temperature sensing layer, the flexible micro-nano coil assembly includes a coil base, a first micro-nano coil layer, an intermediate insulating layer, a second micro-nano coil layer and a coil packaging layer which are stacked in sequence; The coil substrate and the coil packaging layer are made of polyimide, and the middle insulating layer is made of insulating polymer.

6. The pressure-temperature dual-mode sensor according to claim 5, characterized in that: The first micro-nano coil layer is connected to a first electrode, the second micro-nano coil layer is connected to a second electrode, the first electrode and the second electrode are used for externally connecting a pressure measurement signal for pressure testing; the temperature sensing layer is connected to a third electrode and a fourth electrode, the third electrode and the fourth electrode are used for externally connecting a stable measurement signal for temperature testing.

7. The pressure-temperature dual-mode sensor according to claim 1, characterized in that: The temperature sensing layer is prepared by squeezing a temperature-sensitive solution consisting of a mixture of a temperature-sensitive material and soft silica gel into a mold via a syringe; the temperature-sensitive material includes any one of vanadium oxide, Pedot:pss and graphene.

8. The pressure-temperature dual-mode sensor according to claim 1, characterized in that: The pressure sensing layer is prepared by pouring a magnetic solution consisting of a mixture of magnetic powder particles and soft silica gel into a 3D printing mold and then performing inverted molding; the mass fraction of the magnetic powder particles in the magnetic solution is 10% to 90%; and the magnetic powder particles are neodymium iron boron magnetic powder.

9. A method for preparing a pressure-temperature dual-mode sensor according to any one of claims 1 to 8, characterized in that: The method comprises: S1, preparing the flexible micro-nano coil assembly on the base layer; S2, bonding the temperature sensing layer to the flexible micro-nano coil assembly through the bonding layer; S3, forming a gradient inclined magnetic column array distributed in a rectangular array on the temperature sensing layer to obtain the pressure-temperature dual-mode sensor.

10. Application of the pressure-temperature dual-mode sensor according to any one of claims 1 to 8 or the pressure-temperature dual-mode sensor prepared by the preparation method according to claim 9 in robots and wearable electronic products.

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