Non-contact sensor

Abstract

The non-contact sensor comprises an electret layer and an electrode layer which are arranged in a stacked mode, the electret layer comprises a charge transmission layer and a charge blocking layer, the charge transmission layer comprises a first polymer matrix and conductive particles, and the migration rate of charges in the charge transmission layer can be increased by adding the conductive particles; the electret layer is arranged on the surface of the electret layer, charges are promoted to migrate from the surface into the charge transmission layer, new charges can be generated at the positions where the charges migrated from the surface are located, the surface charge density and the charge quantity in the electret layer are increased, and under the action of the charge blocking layer, the charges can be prevented from leaking to the electrode layer from the charge transmission layer, charge dissipation is reduced, and the efficiency is improved. The charges can be stably stored in the electret layer for a long time; thus, under the action of the charge transport layer and the charge barrier layer, the charge storage capacity is increased, the sensing distance is increased, the efficiency and accuracy of remote detection are improved, and the performance of the non-contact sensor is improved.

Description

Technical Field

[0001] The present application relates to the field of sensor technology, and in particular to a non-contact sensor. Background Art

[0002] Contactless sensing technology is an integral part of modern robotics, human-machine interaction, and wearable electronic devices, and is able to detect stimuli without physical interaction. Electret materials are at the heart of contactless sensing technology because they can retain charge for a long time, acting as permanent electrostatic field generators. To improve the performance of electret materials, this can be achieved by increasing the surface charge density, but the surface charge is unstable and is prone to attenuation and dissipation under complex environmental conditions, resulting in reduced efficiency and accuracy of long-distance detection, thereby reducing the performance of contactless sensors. Summary of the invention

[0003] The embodiment of the present application provides a non-contact sensor to improve the performance of the non-contact sensor.

[0004] Specifically, an embodiment of the present application provides a non-contact sensor, comprising: an electret layer and an electrode layer stacked;

[0005] The electret layer comprises: a charge transport layer and a charge blocking layer, wherein the charge blocking layer is arranged between the charge transport layer and the electrode layer; the charge transport layer comprises: a first polymer matrix and conductive particles.

[0006] In this way, the addition of conductive particles can increase the mobility of charges in the charge transfer layer, promote the migration of charges from the surface to the charge transfer layer, and generate new charges at the location of the charges migrated from the surface, increasing the surface charge density and the amount of charge in the electret layer. Under the action of the charge blocking layer, the charge can be blocked from leaking from the charge transfer layer to the electrode layer, reducing charge dissipation, so that the charge can be stably stored in the electret layer for a long time. Under the action of the charge transfer layer and the charge blocking layer, the storage capacity of the charge is increased, thereby increasing the sensing distance, improving the efficiency and accuracy of long-distance detection, and thus improving the performance of the contactless sensor. BRIEF DESCRIPTION OF THE DRAWINGS

[0007] Figure 1 A schematic diagram of the structure of a non-contact sensor provided in an embodiment of the present application;

[0008] Figure 2 A working principle diagram of the charge transport layer provided in the embodiments of the present application;

[0009] Figure 3 The effect of the amount of conductive particles added to the charge transport layer provided in the embodiments of the present application on the performance;

[0010] Figure 4 A schematic diagram of the structure of another non-contact sensor provided in an embodiment of the present application;

[0011] Figure 5 A schematic diagram of the structure of another non-contact sensor provided in an embodiment of the present application;

[0012] Figure 6 The effect of polymer column height on performance provided in the examples of this application;

[0013] Figure 7 The effect of the amount of ferroelectric material added on the performance provided in the embodiments of the present application;

[0014] Figure 8 A schematic diagram of a charge blocking layer provided in an embodiment of the present application;

[0015] Fig. 9 The effect of the electret layer structure provided in the embodiments of the present application on the leakage current;

[0016] Fig.10 The effect of the electret layer structure on the performance provided in the embodiments of the present application;

[0017] Fig.11 The examples and comparative examples provided in the present application are affected by temperature, humidity and light;

[0018] Fig.12 The results of the high temperature and high humidity accelerated life test provided in the examples of this application;

[0019] Fig.13 This is the result of the remote sensing capability test provided in the embodiments of the present application. Description of the drawings:

[0021] 10-charge transport layer, 20-charge blocking layer, m1-electret layer, m2-electrode layer, m3-object, 11-first polymer matrix, 12-conductive particles, 21-dielectric layer, 22-substrate, 23-polymer column, 24-ferroelectric layer, d1-gap, d2-height of polymer column. DETAILED DESCRIPTION

[0022] The following will be combined with the accompanying drawings to describe in detail a specific implementation of a non-contact sensor provided by an embodiment of the present application. It should be noted that the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of this application.

[0023] The present application embodiment provides a non-contact sensor, such as Figure 1 As shown, it includes: a stacked electret layer m1 and an electrode layer m2; the electret layer m1 includes: a charge transport layer 10 and a charge blocking layer 20, and the charge blocking layer 20 is arranged between the charge transport layer 10 and the electrode layer m2; the charge transport layer 10 includes: a first polymer matrix 11 and conductive particles 12.

[0024] In this way, the addition of conductive particles can increase the mobility of charges in the charge transfer layer, promote the migration of charges from the surface to the charge transfer layer, and generate new charges at the location of the charges migrated from the surface, increasing the surface charge density and the amount of charge in the electret layer. Under the action of the charge blocking layer, the charge can be blocked from leaking from the charge transfer layer to the electrode layer, reducing charge dissipation, so that the charge can be stably stored in the electret layer for a long time. Under the action of the charge transfer layer and the charge blocking layer, the storage capacity of the charge is increased, thereby increasing the sensing distance, improving the efficiency and accuracy of long-distance detection, and thus improving the performance of the contactless sensor.

[0025] Moreover, when an object approaches the charge transfer layer of the contactless sensor, if the electronegativity of the object and the charge transfer layer is different, then under the action of electrostatic induction, charges will be induced on the surface of the charge transfer layer, so that electrical signals can be output through the electrode layer.

[0026] Furthermore, due to the different electronegativity of different objects, when different objects are close to the non-contact sensor, the electrical signals output by the non-contact sensor will be different. Through training and learning, different objects can be identified based on the electrical signals, thereby realizing the ability to identify objects. Furthermore, if multiple non-contact sensors are set as a matrix, the shape and form of the object can also be identified, thereby realizing more recognition functions. The realization of these functions is crucial to promoting enhanced remote perception in embedded artificial intelligence systems, so that complex environments can be accurately detected and interpreted. By integrating innovations in material design and algorithm optimization, it can pave the way for advanced applications of remote sensing technology in robots and human-computer interaction, especially in improving the sensing range and accuracy of embedded artificial intelligence systems. Of course, the specific recognition function can be designed according to actual needs and is not specifically limited here.

[0027] The following is an introduction to the various structures within the non-contact sensor.

[0028] 1. Charge transport layer.

[0029] Optionally, the mass percentage of the conductive particles in the charge transport layer can be set to be greater than 0 and less than 1.5%, such as but not limited to: 0.1%, 0.3%, 0.5%, 0.7%, 0.9%, 1.1%, 1.3%, 1.4% and other values, which can be set according to actual needs and are not specifically limited here. For example, when the mass percentage of the conductive particles in the charge transport layer is large, it means that the proportion of the conductive particles is large, which may cause the agglomeration of the conductive particles, which is not conducive to the migration of the charge, or it may form a continuous conductive network, which will increase the probability of the charge being offset, resulting in a decrease in the charge storage capacity; when the mass percentage of the conductive particles in the charge transport layer is small, it means that the proportion of the conductive particles is small. Although the presence of the conductive particles will increase the charge mobility, if the proportion of the conductive particles is small, the ability to increase the charge mobility may be limited; based on this, setting the mass percentage of the conductive particles in the charge transport layer within the above range can not only obtain a better charge mobility, but also have a higher charge storage capacity, thereby effectively improving the performance of the non-contact sensor.

[0030] Furthermore, the mass percentage of the conductive particles in the charge transport layer can be set to 1.1%, so that the charge transport layer can exhibit excellent charge mobility and excellent charge storage capacity, thereby making the non-contact sensor have excellent performance.

[0031] When the non-contact sensor is used as electronic skin on the skin surface, the non-contact sensor needs to have a certain degree of flexibility. At this time, the material of the first polymer matrix can include but is not limited to flexible polymer materials, such as but not limited to polydimethylsiloxane and other flexible polymer materials. The specific material can be selected according to actual needs and is not specifically limited here. Of course, when the non-contact sensor is used in a scene where deformation is not required, the non-contact sensor can be non-flexible or have a certain degree of flexibility. At this time, the first polymer matrix can be made of any type of polymer material.

[0032] The conductive particles may be made of any material having a conductive function, such as but not limited to carbon black, metal powder, carbon nanotubes, graphene, conductive porous materials and other conductive particles. The material may be selected according to actual needs and is not specifically limited here.

[0033] Optionally, the thickness of the charge transfer layer can be set according to actual needs. For example, when the non-contact sensor is applied on the skin surface as electronic skin, the thickness of the non-contact sensor is generally small, and the thickness of the charge transfer layer is generally set to be small; or when the non-contact sensor is placed on the hard surface of an object, since the non-contact sensor does not need to be deformed, the thickness of the non-contact sensor can be large or small, and the thickness of the charge sensor can also be large or small accordingly.

[0034] The working principle of the charge transport layer is explained below.

[0035] Combination Figure 2 As shown, taking the first polymer matrix as PDMS, and the nylon and the charge transport layer 10 being close to and separated as an example, Figure 2 (a) Figure 2 (b) Figure 2 (c) Figure 2 (d) Figure 2 (e) in the figure are all cases where the charge transport layer 10 is a PDMS layer. Figure 2 (f) Figure 2 (g) Figure 2 (h) Figure 2 (i) Figure 2 (j) in the figure are all cases where the charge transport layer 10 includes PDMS and conductive particles; i Represents the transition time from capacitance effect to charge diffusion / migration effect;

[0036] When the charge transport layer 10 is a PDMS layer, since the electronegativity of nylon is less than that of PDMS, in the process of periodic approach and separation of nylon and the charge transport layer 10, under the action of electrostatic induction, the surface of nylon has positive charge, and the surface of the charge transport layer 10 facing the nylon has negative charge, and positive charge is induced in the electrode layer m2. At this time, the charge transport layer 10 and the electrode layer m2 form a capacitor, so that the non-contact sensor has a capacitive effect, and as time goes by, the positive charge induced in the electrode layer m2 gradually increases under the action of the capacitive effect, such as Figure 2 (a) to Figure 2 When the positive charge induced in the electrode layer m2 reaches a certain amount and reaches saturation, the negative charge of the charge transport layer 10 toward the nylon surface will diffuse / migrate to the inside under the action of the internal polarized molecules, such as Figure 2 (c) to Figure 2 In the stage shown in (e), since the amount of polarizable molecules is small, the amount of negative charges diffused / migrated into the charge transport layer 10 is relatively small.

[0037] When the charge transport layer 10 includes PDMS and conductive particles, the presence of the conductive particles enhances the capacitance effect, so more positive charges can be induced in the electrode layer m2, such as Figure 2 (f) to Figure 2 The stage shown in (h); when the positive charge induced in the electrode layer m2 reaches a certain amount and reaches saturation, the conductive particles can serve as charge capture sites, and combined with the action of polarized molecules, increase the amount of diffusion / migration of negative charges into the charge transport layer 10, such as Figure 2 (h) to Figure 2 The stage shown in (j) in the figure enhances the charge diffusion / migration effect.

[0038] It should be pointed out that when the charge transport layer is a PDMS layer, the charge diffusion / migration effect is not obvious, and the negative charge on the surface of the charge transport layer will also interact with the surrounding water molecules to cause charge dissipation, so from the overall point of view, the amount of negative charge diffused / migrated into the charge transport layer is relatively small. When the charge transport layer includes PDMS and conductive particles, even if there are negative charges on the surface of the charge transport layer that will interact with the surrounding water molecules to cause charge dissipation, the presence of conductive particles enhances the capacitance effect and charge diffusion / migration effect, so the amount of negative charge diffused / migrated into the charge transport layer is also relatively large, and the amount of charge dissipation is not enough to affect the amount of negative charge diffused / migrated.

[0039] Of course, when there are defects or vacancies on the surface of the charge transport layer, the defects or vacancies will also generate additional negative charges, which can further increase the positive charges induced in the electrode layer, thereby also increasing the amount of negative charges diffusing / migrating into the charge transport layer.

[0040] See also Figure 3 As shown, Figure 3 (a) represents the dispersion of the conductive particles 12 in the first polymer matrix 11 when the mass percentage of the conductive particles 12 in the charge transport layer 10 is greater than 0 and less than 1.5%. Figure 3 (b) in FIG. 1 shows the dispersion of the conductive particles 12 in the first polymer matrix 11 when the mass percentage of the conductive particles 12 in the charge transport layer 10 is greater than 1.5%. Figure 3 (c) in FIG. 1 represents the output voltage of the non-contact sensor when the mass percentage of the conductive particles 12 in the charge transport layer 10 is different, and the nylon and the non-contact sensor are periodically approaching and separating. Figure 3It can be found from the results shown in that when the mass percentage of the conductive particles 12 in the charge transport layer 10 is greater than 0 and less than 1.5%, the dispersion effect of the conductive particles 12 is better. When the mass percentage of the conductive particles 12 in the charge transport layer 10 exceeds the above range, the conductive particles 12 are agglomerated due to the large amount of conductive particles 12 added. The occurrence of agglomeration is not conducive to the capture of charges. Therefore, from the results of the output voltage, when the mass percentage of the conductive particles 12 in the charge transport layer 10 is not greater than 1.1%, as the amount of conductive particles 12 added increases, the output voltage gradually increases, which shows that as the conductive particles 12 are added, the output voltage gradually increases. 2 is added, the charge diffusion / migration effect gradually increases, and when the mass percentage of the conductive particles 12 in the charge transport layer 10 is 1.1%, a balance is reached between the dispersibility of the conductive particles 12 and the charge transport efficiency; after the mass percentage of the conductive particles 12 in the charge transport layer 10 is greater than 1.1%, the output voltage gradually decreases, which may be due to the agglomeration of a small amount of conductive particles 12; based on this, by controlling the addition amount of the conductive particles 12, the charge transport layer 10 can have a better charge diffusion / migration effect, thereby making the non-contact sensor have better performance.

[0041] In summary, since the charge transport layer includes the first polymer matrix and the conductive particles, the conductive particles can be dispersed in the first polymer matrix, which can increase the charge mobility of the charge transport layer and give the charge transport layer a higher charge conduction capability. This efficient charge conduction capability determines that the charge can be quickly moved and transferred to the charge blocking layer. And by controlling the amount of conductive particles added, the formation of a continuous conductive network can be avoided. This dispersion effect can prevent the charge from being quickly dissipated to the outside world, so that the charge can stay inside the charge transport layer for a longer time, thereby enhancing the charge retention ability of the charge transport layer and increasing the charge storage capacity.

[0042] Of course, even if the added conductive particles form a continuous conductive network, the existence of the charge blocking layer can still prevent the charge from being dissipated to the outside world, so that the charge can be retained inside the charge transport layer to a certain extent, thereby increasing the charge storage capacity to a certain extent and improving the performance of the non-contact sensor. In other words, when conductive particles are added to the charge transport layer, regardless of whether the proportion of conductive particles added is more or less, the performance of the non-contact sensor can be improved, but the degree of improvement will vary.

[0043] It should be understood that Figure 2 and Figure 3 In order to illustrate the role of the charge transport layer, Figure 2 and Figure 3 Only the charge blocking layer is shown in the figure, but this does not mean that there is no charge blocking layer between the electrode layer and the charge transport layer.

[0044] 2. Charge blocking layer.

[0045] The implementation forms of the charge blocking layer include the following:

[0046] The first :The charge blocking layer includes a ferroelectric layer, that is, the ferroelectric layer is used as the charge blocking layer. In this case, the contactless sensor includes: an electrode layer, a ferroelectric layer and a charge transfer layer stacked in sequence. The ferroelectric layer includes a ferroelectric material. The ferroelectric material can block the charge from leaking from the charge transfer layer to the electrode layer, effectively reducing the charge dissipation, so it can play a charge blocking role, so that the charge can be stably stored inside the electret layer for a long time, increasing the charge storage capacity. In addition, the ferroelectric material has a polarization effect. The external electric field can induce the directional arrangement of the dipoles inside the ferroelectric material to form a strong internal electric field. This internal electric field can expand the ability to capture and retain charge, thereby further increasing the charge storage capacity and further improving the performance of the contactless sensor.

[0047] Among them, the ferroelectric layer includes: a second polymer matrix and a ferroelectric material, that is, the ferroelectric layer is a film layer formed by mixing the second polymer matrix and the ferroelectric material. The second polymer matrix can be but is not limited to any polymer material, such as but not limited to PDMS, PTFE, PE, etc., and the ferroelectric material can be any material with ferroelectric properties, such as but not limited to strontium titanate, barium titanate, sodium potassium niobate, lead zirconate titanate, etc., which can be specifically set according to actual needs and is not specifically limited here.

[0048] The mass percentage of ferroelectric material in the ferroelectric layer can be set to be greater than 0 and less than 16%. If too much ferroelectric material is added, a conductive path may be formed, causing the charge blocking effect to disappear. Therefore, setting the amount of ferroelectric material added within the above range can make the ferroelectric layer have better charge blocking effect.

[0049] The second : The charge blocking layer includes a dielectric layer, that is, the charge blocking layer does not include ferroelectric material, but only uses the dielectric layer as the charge blocking layer. The material making the dielectric layer can be any polymer material or a combination of multiple polymer materials, so the dielectric layer has good insulation properties and the energy level of the dielectric layer is high. This can also block the charge leakage from the charge transfer layer to the electrode layer to a certain extent, and reduce charge dissipation to a certain extent, so it can also play a certain charge blocking role.

[0050] The third :like Figure 4 and Figure 5As shown, the charge blocking layer 20 includes: a dielectric layer 21, a substrate 22, a plurality of polymer columns 23 extending from the surface of the substrate 22, and a ferroelectric layer 24. The substrate 22 and the dielectric layer 21 are respectively arranged on opposite sides of the polymer columns 23, the plurality of polymer columns 23 are arranged in an array, and the ferroelectric layer 24 is arranged in the gaps between the plurality of polymer columns 23; there is a gap d1 between the ferroelectric layer 24 and the dielectric layer 21.

[0051] In this way, the electronegativity of the ferroelectric material in the ferroelectric layer and the dielectric layer must be different, so that the ferroelectric material in the ferroelectric layer and the dielectric layer will respectively induce different charges, thereby forming a built-in electric field E. This built-in electric field E will drive the charge migration, so that the charge blocking layer has a stronger blocking effect and charge capture ability; the ferroelectric material can block the charge from leaking from the charge transfer layer to the electrode layer, effectively reducing the charge dissipation, so it can play a charge blocking role, so that the charge can be stably stored in the electret layer for a long time, increasing the charge storage capacity, thereby further improving the performance of the contactless sensor.

[0052] The ferroelectric layer contacts the surface of the substrate facing the dielectric layer, that is, the ferroelectric layer is directly arranged on the surface of the substrate facing the dielectric layer, so there is no gap between the ferroelectric layer and the substrate, which makes it easy to make a charge blocking layer.

[0053] like Figure 4 As shown, the dielectric layer 21 can be disposed between the electrode layer m2 and the substrate 22. Figure 4 From the structure shown in , the ferroelectric layer 24 is arranged at the top of the gap. Taking the case where both the substrate 22 and the polymer column 23 are made of PDMS as an example, the manufacturing process of such a structure may include: placing the PDMS prepolymer in a template, peeling it off from the template after solidification, and obtaining an integrated structure A of the substrate 22 and the polymer column 23; placing the polymer column 23 upward on a spin coater, pouring a mixed solution of the PDMS prepolymer and the ferroelectric material on the integrated structure A for spin coating, and the mixed solution will sink to the bottom of the gap of the polymer column 23, and after solidification, a ferroelectric layer 24 will be formed in the gap, and a structure B including the substrate 22, the polymer column 23 and the ferroelectric layer 24 will be obtained; thereafter, after laying the dielectric layer 21 on the electrode layer m2, the structure B is inverted on the surface of the dielectric layer 21, so that there is a gap d1 between the ferroelectric layer 24 and the dielectric layer 21, and finally forming a charge transfer layer 10 on the substrate 22, thereby obtaining a non-contact sensor.

[0054] At this time, since the electronegativity of the ferroelectric material is less than that of PDMS, the ferroelectric material induces positive charge and the PDMS induces negative charge, thereby generating a built-in electric field E from the ferroelectric layer to the dielectric layer in the charge blocking layer, as shown in FIG. Figure 4As shown by the solid arrows, assuming that nylon is close to the charge transport layer, under the action of the built-in electric field E, the charge transport layer has a negative charge and the nylon has a positive charge. At this time, the electret layer is a strongly electronegative material.

[0055] like Figure 5 As shown, the dielectric layer 21 can be disposed between the charge transport layer 10 and the substrate 22. Figure 5 From the structure shown in FIG. 1 , the ferroelectric layer 24 is disposed at the bottom of the gap. Continuing to take the substrate 22 and the polymer column 23 made of PDMS as an example, the manufacturing process of such a structure is similar to that of FIG. Figure 4 The difference between the manufacturing process of the structure shown in is that the structure B is placed positively on the electrode layer m2, so that the polymer column 23 is located on the side of the substrate 22 away from the electrode layer m2, and then the dielectric layer 21 and the charge transfer layer 10 are laid separately, thereby obtaining a non-contact sensor.

[0056] Similar to Figure 4 According to the principle in FIG. 1 , a built-in electric field E directed from the ferroelectric layer 24 to the direct layer is also generated in the charge blocking layer 20, such as Figure 5 As shown by the solid arrow, in this case, assuming that nylon is close to the charge transport layer 10, under the action of the built-in electric field E, the charge transport layer 10 has a positive charge and the nylon has a negative charge. At this time, the electret layer is a strongly electropositive material.

[0057] Of course, in the embodiment of the present application, the object close to the charge transport layer is not limited to nylon, but can also be any other material. The embodiment of the present application only uses nylon as an example for illustration.

[0058] Optionally, the height d2 of the polymer column can be set to 10 μm to 50 μm, such as but not limited to 10 μm, 20 μm, 30 μm, 40 μm, 50 μm and other values. It can be set according to actual needs and is not specifically limited here. For example, when the height d2 of the polymer column is too small, it may cause the internal friction effect to decrease, resulting in reduced overall performance. When the height d2 of the polymer column is too large, more defects may be formed and affect the stability of the structure. Therefore, setting the height d2 of the polymer column within the above range can make the non-contact sensor have higher performance and structural stability. Figure 6 As shown in , when the height of the polymer column is 10 μm to 50 μm, the output voltage is relatively high, especially when the height of the polymer column is 40 μm, the output voltage is the highest, which indicates that the performance of the non-contact sensor is better when the height of the polymer column is within the above range.

[0059] It should be understood that the morphology of the polymer column can be any shape such as columnar, conical, irregular, etc., as long as the morphology can separate the ferroelectric layer from the dielectric layer, it belongs to the protection scope of the embodiments of the present application.

[0060] Optionally, the ferroelectric layer can be arranged in the same manner as the first ferroelectric layer arrangement, wherein the output voltage of the non-contact sensor with different addition amounts of ferroelectric material is tested, and the test results are as follows: Figure 7 As shown in, when the mass percentage of ferroelectric material in the ferroelectric layer is greater than 0 and less than 16%, the output voltage is relatively high, especially when the mass percentage of ferroelectric material in the ferroelectric layer is 12%, the output voltage is the highest. This shows that setting the addition amount of ferroelectric material within the above range can make the charge blocking layer have a better charge blocking effect.

[0061] The working principle of the charge blocking layer is explained below.

[0062] By introducing a charge blocking layer, a physical or chemical barrier can be formed between the charge transport layer 10 and the electrode layer m2, which can significantly adjust the charge migration behavior, such as slowing down the migration speed of the charge to the electrode layer m2, preventing the charge from leaking quickly to the electrode layer m2, and providing additional capture sites for the charge, thereby prolonging the retention time of the charge in the electret layer. Figure 8 As shown in the schematic diagram, in the absence of the charge blocking layer 20, Figure 8 As shown in (a), the charges migrate to the electrode layer m2, resulting in a low charge storage efficiency. Figure 8 As shown in (b), a charge trap is established, which effectively prevents the excessive migration of charges, promotes a large amount of charge storage through the built-in electric field between the ferroelectric layer 24 and the dielectric layer 21, enhances the charge retention ability, and significantly increases the number of charges in the electret layer. In this way, the addition of the charge blocking layer 20 minimizes the charge loss and optimizes the charge storage and sensing, thereby significantly improving the performance of the contactless sensor.

[0063] In order to verify whether the electret layer in the embodiment of the present application has achieved the transition from surface charging to large-capacity charging, a leakage current test was performed. The test principle diagram is shown in FIG. Fig. 9 As shown in (a) in the figure, the test results are as follows Fig. 9 As shown in (b), CBL represents charge blocking layer and CTL represents charge transport layer. The test results show that PTFE and PDMS exhibit lower leakage current, indicating that the charge is mainly concentrated on the surface rather than inside. In contrast, the electret layer composed of the charge transport layer and the charge blocking layer shows a significantly higher leakage current. This is because the conductive particles in the charge transport layer provide additional charge migration channels, and the special structure of the charge blocking layer realizes a large amount of charge storage. The synergistic interaction between the charge transport layer and the charge blocking layer optimizes the charge dynamics and retention in the electret layer. These enhanced functions improve the performance and stability of the contactless sensor.

[0064] Furthermore, the performance of the contactless sensors made with different electret layers was verified, e.g. Fig.10 (a) is the case when PDMS is used as the electret layer. Fig.10 (b) is the case where PDMS with 0.3 wt% of conductive particles is added as the electret layer. Fig.10 (c) is the PDMS layer and Figure 6 The case where the charge blocking layer shown constitutes an electret layer, Fig.10 (d) is the charge transport layer and Figure 6 The charge blocking layer shown in the figure constitutes the electret layer. From the results shown in the figure, it can be found that: Fig.10 (a) and Fig.10 Compared with (b), the presence of conductive particles enhances the capacitance effect and charge transfer effect, so the output voltage is significantly improved; Fig.10 (a) and Fig.10 Compared with (c) in Fig. 2, the existence of the charge blocking layer plays a role of charge trap, achieving a better blocking effect, so the output voltage is more significantly improved; the charge transport layer and Figure 4 When the charge blocking layer shown constitutes an electret layer, the output voltage can be further improved, which indicates that the synergistic effect of the charge transport layer and the charge blocking layer effectively increases the charge storage capacity, thereby effectively increasing the performance of the contactless sensor.

[0065] 3. Electrode layer.

[0066] The electrode layer can be made of any material with a conductive function, such as but not limited to conductive metals, conductive metal oxides, conductive organic matter, etc. The specific material can be selected according to actual needs. For example, if the non-contact sensor is used as an electronic skin on the skin surface, and the electrode layer is in direct contact with the skin, it is necessary to consider factors such as air permeability, skin sensitivity, and flexibility during use. Therefore, the electrode layer can be a metal mesh electrode, and the metal can be but not limited to nickel, gold, silver, etc., or the electrode layer can also be other electrodes such as carbon nanotube electrodes. If factors such as hardness and support need to be considered, the electrode layer can be made of a conductive material with a certain hardness to additionally realize the support function of the electrode layer.

[0067] The performance of the non-contact sensor is tested below.

[0068] Embodiment 1: The electret layer in the contactless sensor includes a charge transport layer and a charge blocking layer, wherein the charge blocking layer is Figure 4 The structure shown in;

[0069] Comparative Example 1: The electret layer in the contactless sensor includes a PDMS layer;

[0070] Comparative Example 2: The electret layer in the contactless sensor includes a charge transfer layer;

[0071] Comparative Example 3: The electret layer in the contactless sensor includes a PDMS layer and a charge blocking layer, wherein the charge blocking layer is Figure 4 The structure shown in .

[0072] like Fig.11 As shown, Fig.11 (a) is the output voltage curve of Example 1 and each comparative example under different humidity conditions, Fig.11 (b) is the output voltage curve of Example 1 and each comparative example at different temperatures. It can be found that: the output voltage of Example 1 changes little at different humidity and temperature, indicating that humidity and temperature have little effect on the performance of this electret layer. From another perspective, this electret layer has good stability at different humidity and temperature, reflecting high anti-interference ability in high humidity environment, and can ensure stable operation under complex conditions; and when the ferroelectric material has a high dielectric constant, it effectively slows down the impact of temperature fluctuations on the charge transfer path and prevents charge loss. At the same time, due to its unique stress dispersion characteristics, it reduces the thermal expansion and contraction of the material. Fig.11 (c) is the output voltage curve of Example 1 under light and darkness. It can be found that the output voltage is slightly different regardless of whether it is under light conditions or under dark conditions, indicating that the performance of the electret layer in Example 1 is not affected by the ambient brightness. This is mainly due to the inherent mechanism of the charge transfer layer and the charge blocking layer. This inherent mechanism relies on the dielectric properties and charge regulation mechanism of the material, rather than the photoelectric effect that is sensitive to light. Therefore, no matter how the lighting conditions in the environment change, the non-contact sensor in Example 1 can maintain stable charge output and sensing performance, ensuring its reliability in different light environments.

[0073] Furthermore, high temperature and high humidity accelerated life tests were performed on Example 1 and the comparative examples. The test conditions included: the test temperature was 85° C. and the test humidity was 85%. The test results are shown in FIG. Fig.12 As shown, Fig.12 (a) is the output voltage of Example 1 and each comparative example during long-term operation, Fig.12(b) is the output voltage of Example 1 when it runs for a longer time. From the test results, it can be found that during long-term operation, compared with the comparative examples, the non-contact sensor in Example 1 outputs a higher and more stable output voltage. When the output voltage is recycled for 300,000 times, it is 92.1% of the initial output voltage. When Example 1 runs for 80 days, the output voltage is 93.4% of the initial output voltage. This indicates that the performance degradation is small after long-term use, the stability is better, and it shows good reliability and stability.

[0074] The remote sensing capability of the non-contact sensor in Example 1 was tested, and the test results are as follows: Fig.13 As shown, Fig.13 The electret skin in the device is a non-contact sensor; Fig.13 In (a), the left picture shows the test scenario when the human body is 2.45m away from the non-contact sensor, and the right picture shows the output voltage of the non-contact sensor in this test scenario. From the results shown in the figure, it can be found that when the human body is 2.45m away from the non-contact sensor, the non-contact sensor can accurately detect the human body. Fig.13 In (b), the left picture shows the test scenario when the human body wearing fur is 3m away from the non-contact sensor, and the right picture shows the output voltage of the non-contact sensor in this test scenario. From the results shown in the figure, it can be found that: when the human body wearing fur is 3m away from the non-contact sensor, the non-contact sensor can accurately detect the fur, showing a high remote sensing capability and significantly improving the sensing distance.

[0075] The sensing sensitivity of Example 1 and each comparative example was tested. First, the calculation formula of the sensing sensitivity was given as follows: S = (V1-V2) / (D1-D2), where S represents the sensing sensitivity, V1 represents the output voltage of the non-contact sensor when the distance between the object and the non-contact sensor is D1, and V2 represents the output voltage of the non-contact sensor when the distance between the object and the non-contact sensor is D2; after calculation, it was found that the sensing sensitivity of Example 1 can reach 21.8, while the sensing sensitivities of Comparative Examples 1 to Comparative Examples 3 are less than 2; and the sensing distance per unit area of ​​Example 1 can reach 30.67 cm / cm 2 ; The non-contact sensor provided in the embodiment of the present application exhibits a higher perception sensitivity, and the non-contact sensor has excellent sensing performance.

[0076] In summary, the technical solution provided in the embodiments of the present application has the following advantages:

[0077] 1. The technology transition from surface charge storage to bulk charge storage has been successfully realized, significantly extending the sensing distance to up to 3 meters. This transition not only improves the storage capacity and stability of the charge, but also greatly enhances the remote sensing capability, enabling the sensor to accurately detect and respond to targets at a long distance, thus achieving an important breakthrough in the field of remote sensing and promoting the development and application of non-contact sensing technology.

[0078] 2. A new type of electret is proposed, in which the conductive particles can improve the conductivity of the charge transfer layer and enhance the mobility of the charge in the charge transfer layer. At the same time, the ferroelectric material in the ferroelectric layer significantly improves the ability to capture, transfer and retain charges by inducing a significant polarization effect. This special design enables the electret to dynamically optimize its charge storage and transfer performance under various external conditions (such as temperature, humidity, presence or absence of light, etc.), and automatically adjust the working state to adapt to environmental changes, thereby effectively improving the sensitivity and long-term stability of the non-contact sensor. It overcomes the problems of charge attenuation and failure that are prone to occur in traditional electrets, ensures the reliability of non-contact sensors under complex working conditions, extends the service life, and improves stability in long-term applications.

[0079] Obviously, those skilled in the art can make various changes and modifications to the present application without departing from the spirit and scope of the present application. Thus, if these modifications and variations of the present application fall within the scope of the claims of the present application and their equivalents, the present application is also intended to include these modifications and variations.

Claims

1. A non-contact sensor, characterized in that: include: An electret layer and an electrode layer are stacked; The electret layer comprises: a charge transport layer and a charge blocking layer, wherein the charge blocking layer is arranged between the charge transport layer and the electrode layer; the charge transport layer comprises: a first polymer matrix and conductive particles.

2. The non-contact sensor according to claim 1, characterized in that: The mass percentage of the conductive particles in the charge transport layer is greater than 0 and less than 1.5%.

3. The non-contact sensor according to claim 2, characterized in that: The mass percentage of the conductive particles in the charge transport layer was 1.1%.

4. The non-contact sensor according to claim 1, characterized in that: The material of the first polymer matrix includes polydimethylsiloxane; And / or, the conductive particles are made of materials including: carbon black, metal powder, carbon nanotubes, graphene, and conductive porous materials.

5. The non-contact sensor according to any one of claims 1 to 4, characterized in that: The charge blocking layer includes a ferroelectric layer.

6. The non-contact sensor according to any one of claims 1 to 4, characterized in that: The charge blocking layer includes a dielectric layer.

7. The non-contact sensor according to claim 6, characterized in that: The charge blocking layer further comprises: a substrate, a plurality of polymer columns extending from the surface of the substrate, and a ferroelectric layer, wherein the plurality of polymer columns are arranged in an array, and the ferroelectric layer is arranged in the gaps between the plurality of polymer columns; There is a gap between the ferroelectric layer and the dielectric layer; The substrate and the medium layer are respectively arranged on two opposite sides of the polymer column.

8. The non-contact sensor according to claim 7, characterized in that: The height of the polymer column is 10 μm to 50 μm.

9. The non-contact sensor according to claim 7, characterized in that: The ferroelectric layer contacts a surface of the substrate facing the dielectric layer.

10. The non-contact sensor according to any one of claims 5, 7, 8 and 9, characterized in that: The ferroelectric layer includes: a second polymer matrix and a ferroelectric material, and the mass percentage of the ferroelectric material in the ferroelectric layer is greater than 0 and less than 16%.

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