A pressure sensing system based on electroluminescence

Abstract

The application belongs to the technical field of tactile sensing, and particularly relates to a pressure sensing system based on electroluminescence. The pressure sensing system comprises a light emitting module and a light sensing module. The light emitting module comprises a transparent electrode layer / transparent interdigital electrode layer, an electroluminescence layer, a porous dielectric layer and a stretchable electrode layer which are sequentially stacked from bottom to top. The light emitting module is used for sensing the pressure distribution applied to the surface and generating light with an intensity corresponding to the pressure size in the pressure area. The light sensing module is used for collecting the spatial position distribution and intensity information of the light. The application first proposes a new mechanism of electroluminescence tactile sensing based on the porous dielectric layer, realizes wide-range regulation of the light brightness from the non-light emitting state to the saturated light state, and establishes a direct physical mapping relationship between the applied pressure and the light brightness. The application fundamentally solves the pain point that high resolution, low cost and simple collection cannot be achieved simultaneously in tactile sensing, and provides a new technical path for flexible electronic skin.

Description

Technical Field

[0001] This invention belongs to the field of tactile sensing technology, specifically relating to a pressure sensing system based on electroluminescence. Background Technology

[0002] Touch is a vital channel for living organisms to perceive the world and a core foundation for complex physical interactions. For humans, the tactile discrimination threshold of approximately 40 micrometers in the fingertips allows us to easily distinguish the subtle textures of silk and sandpaper, enabling precise operations such as threading a needle and reading Braille. For embodied intelligence—especially humanoid robots—endowing them with "human-like" or even "superhuman" tactile perception capabilities is a crucial prerequisite for achieving dexterous manipulation and safe physical interaction in unstructured environments, and ultimately evolving from "mechanical entities" into "intelligent entities" with environmental understanding.

[0003] High-resolution flexible tactile sensors, as the core sensing unit of humanoid robot electronic skin, have core value in three dimensions: First, real-time tactile imaging—the sensor needs to convert the pressure distribution of the contact surface into a two-dimensional image in real time with a sufficiently high spatial resolution (e.g., better than 100 micrometers), enabling the robot to "see" the texture, contour, and edges of the object it is in contact with; Second, multi-dimensional force detection—in addition to normal force (pressing), it also needs to sense shear force (sliding) and tensile force to accurately determine the contact state (grasping, sliding, twisting, etc.) and achieve stable grip without damaging the object; Third, large-area conformal integration—the sensor must have flexible or even stretchable characteristics to conform to the robot's fingers, palms, arms, and even the curved surfaces of the whole body to form a complete tactile sensing skin.

[0004] However, traditional piezoresistive and capacitive tactile sensors have long faced three major technical bottlenecks in simultaneously achieving high resolution, low cost, and simple signal acquisition: First, spatial resolution is limited. Resolution is determined by electrode density, but the denser the electrodes, the more severe the signal crosstalk between adjacent units, leading to blurred and distorted tactile images. Currently, reliable resolution is difficult to stabilize below 200 micrometers, far exceeding the human fingertip's discrimination threshold of about 40 micrometers, making it difficult to meet the needs of fine texture recognition. Second, manufacturing costs are high. To achieve micrometer-level electrode linewidths, semiconductor processes such as photolithography and vacuum coating are required, involving ultra-clean environments, expensive equipment, complex procedures, and high-cost raw materials. The manufacturing cost of a sensor of tens of square centimeters is comparable to that of a high-end chip of the same area, making it difficult to achieve large-area, low-cost, large-scale applications. Third, signal reading efficiency is low. Traditional row-column orthogonal structures require row-by-row scanning sampling. An M×N array requires M+N leads, and the acquisition time is proportional to M×N. As resolution increases, the number of leads increases linearly, circuit complexity increases exponentially, frame rate decreases, and power consumption increases, making it difficult to achieve high frame rate, high resolution, and low power consumption simultaneously.

[0005] Furthermore, while recent advancements in visual-tactile sensors have yielded breakthroughs in resolution, their inherent architecture suffers from inherent limitations. These sensors typically employ a stacked structure of "marker layer - transparent elastomer - light source - lens - image sensor," reconstructing tactile pressure distribution by capturing deformation images with a built-in camera. This architecture leads to three volume issues: First, the light source system occupies incompressible space, requiring multiple LED light sources and light guides to ensure uniform illumination, while maintaining a specific distance from the imaging area, making it difficult to compress the sensor thickness to below 5 millimeters. Second, the lens and image sensor require sufficient working distance; the geometric constraints of object distance and image distance often result in optical module thicknesses reaching 10-20 millimeters, far exceeding the space accommodating a robot's finger joint. Third, there is a fundamental contradiction between rigid optical components and the need for flexible skin; rigid components such as lenses and image sensors cannot be bent or stretched, and in large-area applications, they can only be distributed as discrete "rigid islands," creating blind spots and drastically increasing assembly costs. In summary, visual-tactile sensors, due to their reliance on the optical imaging architecture of "light source-lens-camera", have inherent problems such as large size, difficulty in reducing thickness, and incompatibility between rigidity and flexibility. They are difficult to embed inside the narrow finger joints of robots, and cannot be spliced ​​together at low cost to form a large area of ​​conformal electronic skin, which seriously limits their practical deployment capability in humanoid robot dexterity hand and whole-body tactile perception scenarios.

[0006] Alternating current electroluminescent (ACEL) devices possess significant advantages such as large-area uniform light emission, low manufacturing cost, and simple device structure, and are expected to drive a fundamental revolution in the design concept of high-resolution tactile sensors. The luminous intensity of an ACEL device is positively correlated with the voltage amplitude applied across its terminals. When connected in series with a pressure-sensitive unit in an AC drive circuit, external pressure causes changes in the electrical parameters (such as resistance or capacitance) of the pressure-sensitive unit, thereby adjusting the voltage division ratio on the ACEL device and ultimately directly converting tactile information into a visualized change in luminous intensity. However, this external series scheme can only achieve quantitative sensing of single-point pressure, and is limited by the spatial arrangement of discrete components and the complexity of lead wires, making it difficult to extend to high-resolution pressure distribution imaging and multi-dimensional force detection. Integrating the pressure-sensitive layer inside the ACEL device is expected to overcome the spatial resolution limitations of the external series scheme. Traditional integration schemes use porous piezoresistive materials as pressure-resistance conversion layers, and their brightness regulation relies on a series voltage division mechanism: changes in the resistance of the piezoresistive layer modulate the effective voltage amplitude across the luminescent layer. To achieve high contrast control, this scheme needs to simultaneously satisfy two conditions: high initial resistance (ensuring the dark state) and a significant decrease in resistance (ensuring the bright state). However, there is an inherent contradiction between these two conditions—the magnitude of resistance change is negatively correlated with the initial resistance: high initial resistance (low filler content or high porosity) will compress the magnitude of the piezoresistive resistance change, resulting in insufficient brightness in the bright state; conversely, pursuing a large resistance change by increasing the filler content or decreasing the porosity will decrease the initial resistance, causing light leakage in the dark state and a decrease in contrast. This contradiction makes it difficult for schemes based on porous piezoresistive materials to achieve wide-range, high-contrast brightness control from the dark state to the saturated bright state.

[0007] Therefore, to address the aforementioned technical issues, it is necessary to develop a novel pressure-sensitive layer to achieve a pressure sensing system based on electroluminescence that enables wide-range, high-contrast control of the luminescence brightness of ACEL devices. Summary of the Invention

[0008] To address the problems existing in the prior art, this invention provides a pressure sensing system based on electroluminescence. It proposes for the first time a novel electroluminescent tactile sensing mechanism based on a porous dielectric layer, enabling wide-range control of luminescence brightness from a non-luminescent state to a saturated bright state, and establishing a direct physical mapping relationship between applied pressure and luminescence brightness.

[0009] To achieve the above objectives, the technical solution adopted by the present invention is as follows: The present invention provides a pressure sensing system based on electroluminescence, including a light-emitting module and a light-sensing module, wherein the light-emitting module is disposed directly above the light-sensing module; The light-emitting module includes a transparent electrode layer, an electroluminescent layer, a porous dielectric layer, and a stretchable electrode layer stacked sequentially from bottom to top; or, the light-emitting module includes a transparent interdigitated electrode layer, an electroluminescent layer, a porous dielectric layer, and a stretchable electrode layer stacked sequentially from bottom to top.

[0010] Furthermore, the optical sensing module can be any one of an image sensor, a photodetector array, or a photoelectric conversion material layer array.

[0011] Furthermore, the light-emitting module is driven by high-frequency alternating current.

[0012] Furthermore, when the light-emitting module is powered on and its surface is subjected to pressure, the pressure causes local compression of the porous dielectric layer, resulting in an increase in the dielectric constant of the pressure area and an increase in the electric field strength at the corresponding electroluminescent layer, thereby enhancing the luminous brightness of the pressure area.

[0013] Furthermore, the light-emitting module is used to sense the pressure distribution applied to the surface and generate light emission in the pressure area with an intensity corresponding to the pressure magnitude; the light-sensing module is used to collect the spatial position distribution and intensity information of the light emission; the light emission intensity of the light-emitting module increases with increasing pressure and decreases with decreasing pressure, and the light-emitting module stops emitting light when the pressure is removed.

[0014] Furthermore, the porous dielectric layer has a relative permittivity greater than 5, a porosity greater than 50%, and a compression recovery rate greater than 90%.

[0015] Furthermore, the electroluminescent layer is composed of an alternating current electroluminescent material.

[0016] Furthermore, the alternating current electroluminescent material is at least one of sulfide-based luminescent materials, oxide-based luminescent materials, nitride-based luminescent materials, and perovskite-based luminescent materials.

[0017] Furthermore, the sulfide-based luminescent material is at least one of copper-doped zinc sulfide, manganese-doped zinc sulfide, and rare-earth-doped zinc sulfide.

[0018] Furthermore, the perovskite-based luminescent material is at least one of all-inorganic perovskite, organic-inorganic hybrid perovskite, all-inorganic perovskite nanocrystals, and organic-inorganic hybrid perovskite nanocrystal seeds.

[0019] Compared with the prior art, the beneficial effects of the present invention are: This invention proposes an electroluminescent pressure sensing system, which for the first time presents a novel electroluminescent tactile sensing mechanism based on a porous dielectric layer. This mechanism enables wide-range modulation of luminescence brightness from a non-luminescent state to a saturated bright state, establishing a direct physical mapping relationship between applied pressure and luminescence brightness. Traditional solutions rely on electrode arrays and point-by-point scanning, resulting in low resolution and complex processes. This invention utilizes the continuous change in dielectric constant of the porous dielectric layer under pressure to modulate the brightness of the luminescent layer, achieving a one-step conversion from pressure distribution to light intensity distribution. It allows for the simultaneous acquisition of a full-field high-resolution pressure image via an image sensor without complex readout circuitry. Furthermore, the porous structure exhibits differentiated response characteristics to normal and tangential forces, enabling decoupling and multi-dimensional force monitoring. This innovation fundamentally solves the pain point of simultaneously achieving "high resolution, low cost, and easy acquisition" in tactile sensing, providing a completely new technological path for flexible electronic skin. Attached Figure Description

[0020] Figure 1 This is a schematic diagram of an AC electroluminescent pressure sensing system based on a CCD / CMOS camera as the light sensing module.

[0021] Figure 2 This is a schematic diagram of an AC electroluminescent pressure sensing system based on a perovskite photodetector array as the optical sensing module.

[0022] Figure 3 This is a schematic diagram of the electroluminescence-based pressure sensing system in Example 5.

[0023] Figure 4 Photograph (a) and cross-sectional optical micrograph (b) of a porous dielectric layer based on PDMS / BaTiO3 show the porous network structure formed by BaTiO3 particles dispersed in the PDMS matrix.

[0024] Figure 5 SEM image (a) and EDS energy spectrum (b) of PDMS / BaTiO3 porous dielectric layer.

[0025] Figure 6 Photograph of electrospun TPU film (a), scanning electron microscope (SEM) image of electrospun TPU fiber film (b), and stress-strain curve of electrospun TPU film (c).

[0026] Figure 7 This is a schematic diagram of a pressure imaging test based on an electroluminescent pressure sensing system.

[0027] Figure 8 This is an image showing the light intensity distribution of an electroluminescent pressure sensing system under different pressures.

[0028] Figure 9Schematic diagram of luminescence intensity testing based on an electroluminescent pressure sensing system.

[0029] Figure 10 Electroluminescence spectra (a) and pressure-luminescence intensity curves (b) of an electroluminescence-based pressure sensing system under different pressures.

[0030] Figure 11 This is a schematic diagram of the patterned pressure imaging resolution test based on an electroluminescent pressure sensing system.

[0031] Figure 12 This image represents the resolution of a pressure monitoring system based on electroluminescence for a striped microstructure mold.

[0032] Figure 13 This is a resolution image of a pressure monitoring system based on electroluminescence for a mold of the letter "s".

[0033] Among them, 11 is a stretchable electrode layer; 12 is a porous dielectric layer; 13 is an electroluminescent layer; 14 is a transparent electrode layer; and 2 is a photosensitive module. Detailed Implementation

[0034] The specific embodiments of the present invention will be further described below. It should be noted that these descriptions are for the purpose of aiding understanding the present invention, but do not constitute a limitation thereof. Furthermore, the technical features involved in the various embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0035] Unless otherwise specified, the experimental methods used in the following embodiments are conventional methods, and the experimental materials used in the following embodiments are all available through conventional commercial channels.

[0036] Example 1: Preparation of porous dielectric layer Weigh 1.5 g of polydimethylsiloxane (PDMS) main agent. Weigh out the corresponding amounts of barium titanate and citric acid according to a mass ratio of barium titanate:PDMS:citric acid = 2:1:3. Add the PDMS main agent (Sylgard 184) and barium titanate to a mixing container and mechanically stir until uniformly dispersed. Weigh 0.15 g of Sylgard 184 curing agent (a platinum-based curing agent for polydimethylsiloxane) according to a mass ratio of PDMS main agent to curing agent of 10:1, and add it to the above mixture. Continue stirring until fully mixed. Weigh 4.5 g of citric acid as a pore-forming agent and add it to the above slurry. Continue stirring until a uniformly dispersed mixed slurry is obtained. Take an appropriate amount of the mixed slurry and clamp it between two 5 cm × 5 cm glass plates. Control the film thickness by adjusting the clamping distance. mm, and use clamps to fix the glass plate; place the above assembly in an 80℃ oven for curing for 2 hours; after curing, immerse the sample in a mixed solution of anhydrous ethanol and deionized water, and perform multiple ultrasonic cleanings and change the cleaning solution multiple times to fully remove the citric acid pore-forming agent, and finally obtain a porous dielectric layer.

[0037] Example 2: Preparation of the electroluminescent layer Weigh 5 g of PDMS base agent (Sylgard 184), and weigh 15 g of ZnS luminescent material (optional: average particle size 5-10 μm, doped with copper) at a mass ratio of PDMS base agent:ZnS = 1:3. Add the PDMS base agent and ZnS powder to a mixing container and stir with a mechanical stirrer (500 rpm) for 10 minutes until ZnS is uniformly dispersed in the PDMS matrix. Weigh 0.5 g of Sylgard 184 curing agent (polydimethylsiloxane with platinum catalyst curing agent) at a mass ratio of PDMS base agent:curing agent 10:1 and add it to the above mixture. Continue stirring at 500 rpm for 5 minutes until fully mixed to obtain the luminescent paste. Use a blade coating process to uniformly coat the above luminescent paste onto the cleaned glass substrate surface, adjusting the blade gap to control the wet film thickness to 200 μm. Place the coated sample in an 80℃ constant temperature oven for 2 hours to cure, obtaining the electroluminescent layer.

[0038] Example 3: Fabrication of a stretchable electrode layer BASF 1185A TPU was weighed and added to a mixed solvent of DMF and THF in a volume ratio of 1:1. The mixture was stirred thoroughly until the TPU was completely dissolved, preparing a spinning solution with a TPU mass fraction of 20 wt%. This spinning solution was added to a syringe, and electrospinning was performed using an electrospinning device. The spinning voltage was set to 10.07 kV, the receiving distance to 13 cm, and the feed speed to the range of 0.8–8 mL / h. TPU fibers were collected using a flat-plate receiving method. By controlling the spinning time to 60 min, an elastic TPU porous electrospun membrane was obtained. The resulting TPU electrospun membrane has a three-dimensional porous network structure composed of continuous TPU fibers. The membrane is flexible, bendable, and has a certain degree of stretchability. After drying, the obtained TPU porous membrane was immersed in an ionic liquid (1-ethyl-3-methylimidazolium tetrafluoroborate) and repeatedly squeezed to allow the ionic liquid to fully penetrate and fill the three-dimensional porous structure of the TPU fiber network. After removal, the sample is suspended vertically and left to stand for 5 minutes to allow excess ionic liquid to drip off naturally. Then, the residual liquid on the membrane surface is gently absorbed with filter paper to obtain an ionic liquid-loaded elastic composite membrane. This composite membrane can be used as a stretchable ion-conducting electrode in flexible sensors, wearable devices, or flexible electronic devices.

[0039] Example 4: Assembly of ACEL devices An ITO / PET transparent electrode is provided as the bottom electrode layer; an electroluminescent layer prepared according to the method described in Example 2 is attached to the upper surface of the ITO / PET transparent electrode; a porous dielectric layer prepared according to the method described in Example 1 is attached to the upper surface of the light-emitting layer; and a stretchable electrode layer prepared according to the method described in Example 3 is attached to the upper surface of the porous dielectric layer, forming a stacked structure from bottom to top consisting of an ITO / PET transparent electrode, an electroluminescent layer, a porous dielectric layer, and a stretchable electrode layer.

[0040] Example 5: Assembly of an electroluminescent pressure sensing system The optical sensing module employs a CMOS image sensor. Specifically, a commercially available HBV-1917HD V33 image sensor is selected, with a photosensitive array size of 1920×1080 pixels and a maximum acquisition frame rate of 30 fps (frames / second). This sensor is used to acquire the light intensity distribution image generated by the light-emitting module (ACEL device prepared in Example 4) under pressure, and converts the light signal into a digital image signal for output to the subsequent processing unit. A schematic diagram of the electroluminescent pressure sensing system is shown below. Figure 3 As shown.

[0041] Test Example 1: Pressure Testing A schematic diagram of the pressure testing experiment is shown below. Figure 7As shown. The test was conducted using a universal tensile testing machine (model: TSMT EM2.502, force sensor model: Transcell BSA-50kg) with a 15 mm diameter cylindrical stainless steel flat-head indenter. Before the test, the light-emitting module was placed horizontally at the center of the lower platen of the testing machine, and a CMOS image sensor (model: HBV-1917HD V33, resolution: 1920×1080 pixels, frame rate: 30 fps) was tightly attached to the bottom of the light-emitting module, ensuring that the photosensitive surface of the sensor was facing the lower surface of the light-emitting layer to completely record the light intensity distribution of the light-emitting area. The CMOS image sensor was connected to a computer via a data cable to acquire and store the light-emitting pattern in real time. The 15 mm diameter cylindrical indenter was fixed directly below the force sensor of the universal tensile testing machine, and the position of the indenter was adjusted so that its axis coincided with the central axis of the light-emitting module to ensure that the pressure was applied evenly to the surface of the light-emitting module. During the test, the testing machine moved downward at a loading rate of 5 mm / min, applying normal pressure to the light-emitting module through the indenter. The pressure value was recorded in real time by a force sensor built into the testing machine, with the maximum pressure set at 300 N (corresponding to a stress of approximately 1.7 MPa applied by the indenter). During loading, a CMOS image sensor continuously acquired the luminescence pattern of the luminescent layer; image acquisition was synchronized with pressure loading, and the recording frequency was 10 frames / second. The light intensity distribution images of the electroluminescent pressure sensing system under different pressures obtained from the pressure test are shown below. Figure 8 As shown, this sensing system exhibits stable pressure-luminescence response characteristics within a pressure range of 0–1.7 MPa. The luminescence in the pressurized area becomes brighter as the applied pressure increases.

[0042] A schematic diagram of the luminescence intensity test based on the electroluminescent pressure sensing system is shown below. Figure 9As shown, to quantitatively characterize the relationship between luminescence intensity and applied pressure, a fiber optic spectrometer (model: Ocean Optics USB2000, spectral range: 340–1020 nm) was used to collect electroluminescence spectra under different pressures. During testing, the fiber optic probe of the spectrometer was fixed directly above the surface of the luminescent layer of the light-emitting module, approximately 5 mm away, to ensure that the intensity of the light signal received by the fiber optic probe was stable and representative. The fiber optic probe was connected to the spectrometer via an optical fiber, and the spectrometer was connected to a computer via a USB data cable to record spectral data in real time. During the test, the spectral acquisition parameters were set as follows: integration time was set to 100 ms, averaging was set to 3 times, and smoothness was set to 5, to achieve a balance between signal intensity and signal-to-noise ratio. After each pressure was applied, the force sensor reading was stabilized and held for 3 seconds before triggering the spectrometer to record the electroluminescence spectrum under the current pressure. The spectral data was exported in ASCII format for subsequent analysis of parameters such as emission peak position, peak intensity, and integration area. The pressure loading process was conducted simultaneously with the aforementioned pressure imaging test. Specifically, pressure was continuously applied at a loading rate of 5 mm / min within the range of 0 to 300 N, and the corresponding spectral data (0 kPa, 56.59 kPa, 113.17 kPa, 226.36 kPa, 282.95 kPa, 424.41 kPa, 565.90 kPa, 707.36 kPa, 848.85 kPa, 990.30 kPa, 1.13 MPa, 1.27 MPa, 1.41 MPa, 1.56 MPa, 1.70 MPa) were recorded. To ensure data reliability, each pressure point was tested three times, and the average spectrum was taken as the representative spectrum at that pressure. The electroluminescence spectra of the electroluminescence-based pressure sensing system under different pressures are shown below. Figure 10 As shown in (a), all spectra exhibit a distinct main emission peak at approximately 510 nm, corresponding to the characteristic emission of the ZnS:Cu luminescence center. The pressure-luminescence intensity curves are shown below. Figure 10 As shown in (b), the spectral intensity monotonically increases with increasing applied pressure. This is attributed to the compression of the porous dielectric layer under pressure, which increases the effective dielectric constant, leading to an increase in the partial voltage across the luminescent layer and thus enhancing the electric field intensity of the luminescent layer. The spectral peak position does not change with pressure, indicating that the sensing system has good wavelength stability in the range of 0–1.7 MPa.

[0043] When an external force is applied to the porous dielectric layer, its internal porous structure is compressed, reducing its thickness and expelling air. This results in a significant increase in the effective dielectric constant of the three-phase composite system composed of barium titanate (BaTiO3) particles, PDMS matrix, and air, and a corresponding decrease in its AC impedance. In the series voltage divider circuit of the ACEL device, the decrease in impedance redistributes the voltage that was originally falling on the dielectric layer to the light-emitting layer, leading to an increase in the local electric field intensity of the light-emitting layer, thereby exciting the ZnS:Cu light-emitting material to emit stronger light. Therefore, the pressure distribution is directly converted into the spatial distribution of luminous intensity, and the brightness of the pressurized area is positively correlated with the magnitude of the local pressure, thus achieving real-time visualization of the pressure distribution without the need for complex readout circuits.

[0044] Test Example 2: High-resolution imaging test A schematic diagram of the patterned pressure imaging resolution test experiment is shown below. Figure 11 As shown. To evaluate the spatial resolution capability of the sensing system, a stainless steel mold with a striped microstructure and an "S" pattern on its surface, prepared in the laboratory, was used. During testing, the patterned mold was placed between the indenter and the light-emitting module, with the patterned surface of the mold facing the upper surface of the light-emitting layer and in close contact. A normal pressure of 200 N (corresponding to a stress of approximately 1.13 MPa) was applied using a universal tensile testing machine, causing the microstructure pattern on the mold surface to be transferred to the light-emitting module through pressure, forming a corresponding stress distribution on the surface of the light-emitting layer. During the pressure loading process, a CMOS image sensor (model: HBV-1917HD V33, resolution: 1920×1080 pixels, frame rate: 30 fps) located at the bottom of the light-emitting module acquired the light-emitting pattern of the light-emitting layer in real time. The acquired image data was transmitted to a computer and stored via a data cable. By comparing the light-emitting pattern acquired by the CMOS image sensor with the original microstructure pattern of the test mold, the ability of the sensing system to resolve and reproduce micron-level pressure distribution characteristics can be intuitively evaluated. The pressure monitoring resolution image of the striped microstructure mold obtained by the electroluminescent pressure sensing system is shown in the figure below. Figure 12 As shown; the pressure monitoring resolution image of the “S” letter mold by the electroluminescent pressure sensing system is as follows. Figure 13 As shown. From Figure 12 and Figure 13 As can be seen, the electroluminescence-based pressure sensing system achieved clear and accurate luminescent imaging of both stripe microstructures (minimum linewidth 70 μm) and "S" letter micropatterns (minimum linewidth 150 μm), with sharp stripe boundaries and complete letter outlines. This result demonstrates that high-resolution pressure imaging within 200 μm can be easily achieved based on electroluminescence.

[0045] The embodiments of the present invention have been described in detail above, but the present invention is not limited to the described embodiments. For those skilled in the art, various changes, modifications, substitutions, and variations can be made to these embodiments without departing from the principles and spirit of the present invention, and these variations still fall within the protection scope of the present invention.

Claims

1. A pressure sensing system based on electroluminescence, characterized in that, It includes a light-emitting module and a light-sensing module, with the light-emitting module positioned directly above the light-sensing module; The light-emitting module includes a transparent electrode layer, an electroluminescent layer, a porous dielectric layer, and a stretchable electrode layer stacked sequentially from bottom to top; or, the light-emitting module includes a transparent interdigitated electrode layer, an electroluminescent layer, a porous dielectric layer, and a stretchable electrode layer stacked sequentially from bottom to top.

2. The pressure sensing system based on electroluminescence according to claim 1, characterized in that, The optical sensing module can be any one of an image sensor, a photodetector array, or a photoelectric conversion material layer array.

3. The pressure sensing system based on electroluminescence according to claim 1, characterized in that, The light-emitting module is driven by high-frequency AC power.

4. The pressure sensing system based on electroluminescence according to claim 1, characterized in that, When the light-emitting module is powered on and its surface is subjected to pressure, the pressure causes local compression of the porous dielectric layer, resulting in an increase in the dielectric constant of the pressure area and an increase in the electric field strength at the corresponding electroluminescent layer, thereby enhancing the brightness of the light emitted from the pressure area.

5. A pressure sensing system based on electroluminescence according to claim 1, characterized in that, The light-emitting module is used to sense the pressure distribution applied to the surface and generate light emission in the pressure area with an intensity corresponding to the pressure magnitude; the light-sensing module is used to collect the spatial position distribution and intensity information of the light emission; the light emission intensity of the light-emitting module increases with increasing pressure and decreases with decreasing pressure, and the light-emitting module stops emitting light when the pressure is removed.

6. A pressure sensing system based on electroluminescence according to claim 1, characterized in that, The porous dielectric layer has a relative permittivity greater than 5, a porosity greater than 50%, and a compression recovery rate greater than 90%.

7. A pressure sensing system based on electroluminescence according to claim 1, characterized in that, The electroluminescent layer is composed of an alternating current electroluminescent material.

8. A pressure sensing system based on electroluminescence according to claim 7, characterized in that, The alternating current electroluminescent material is at least one of sulfide-based luminescent materials, oxide-based luminescent materials, nitride-based luminescent materials, and perovskite-based luminescent materials.

9. A pressure sensing system based on electroluminescence according to claim 8, characterized in that, The sulfide-based luminescent material is at least one of copper-doped zinc sulfide, manganese-doped zinc sulfide, and rare-earth-doped zinc sulfide.

10. A pressure sensing system based on electroluminescence according to claim 8, characterized in that, The perovskite-based luminescent material is at least one of the following: all-inorganic perovskite, organic-inorganic hybrid perovskite, all-inorganic perovskite nanocrystals, and organic-inorganic hybrid perovskite nanocrystals.

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