Flexible force-induced luminescence microstructure optical waveguide and preparation method thereof

Abstract

The invention discloses a flexible force-induced luminescence microstructure optical waveguide and a preparation method thereof. The flexible mechanoluminescence microstructure optical waveguide comprises an inner-layer fiber core, n mechanoluminescence composite blocks tightly attached to the inner-layer fiber core, a wrapping layer wrapping the inner-layer fiber core and the n mechanoluminescence composite blocks, and a protection layer coating the surface of the wrapping layer. The n mechanoluminescence composite blocks generate fluorescence signals with different colors under the action of external stress, the fluorescence signals are collected through the inner-layer fiber core and the cladding of the optical waveguide and are transmitted to a far end along the inner-layer fiber core to be detected and demodulated, the sensing section corresponding to stress is determined through the demodulated color, and the corresponding stress is determined through the luminous intensity. The composite material is good in biocompatibility, integrates sensing and transmission functions, and can be used in human body wearable equipment. According to the preparation method, different structures can be prepared in the optical waveguide layer by layer in a mode of customizing different molds, and different purposes are met by integrating different materials.

Description

Technical Field

[0001] The present invention relates to the technical field of optical fiber sensors, and particularly relates to a flexible force-induced luminescence microstructured optical waveguide and a preparation method thereof. Background Art

[0002] The semiconductor and metal materials used in traditional stress sensors are hard and not easy to bend, which is not conducive to detecting human physiological activities. Flexible stress sensors can adhere to the human skin and are suitable for wearable devices. Although quartz optical fibers have excellent optical properties, their brittleness and hardness limit their applications. Flexible polymer optical waveguides are superior to quartz optical fibers in terms of anti-bending and anti-tensile properties, and polymer materials have acid and alkali corrosion resistance and low cost, which is conducive to large-scale production. Their applications are suitable for sensing such as bending, pressure, and displacement in human health monitoring.

[0003] Force-induced luminescence materials have good luminescence repeatability and have application potential in mechanical sensing. At present, research work has been devoted to the design and development of sensors based on force-induced luminescence materials (a micro-displacement travel switch based on force-induced luminescence flexible optical fiber (CN118842459A)). However, these force-induced luminescence-based sensors have relatively simple structures and are difficult to achieve multiple functions, such as distributed sensing. With the increasing urgent demand for flexible wearable strain sensors, flexible force-induced luminescence fiber sensors (a flexible force-induced luminescence multi-core optical fiber and its preparation method and shape sensing system (CN116449482A)) use a single-color force-induced luminescence material to achieve the shape sensing function, but the position of the force cannot be determined, and the requirements for the optical signal detection unit are relatively high. It cannot transmit signals remotely and requires connecting complex equipment, making it difficult to be used in human wearable devices.

[0004] The introduction of microstructures can increase the contact area between the sensor and the object to be measured under the same pressure, thereby improving the sensitivity. By designing microstructures with high compressibility, the sensor can deform better under the action of external forces, thus expanding the measurement range. At present, the preparation methods of flexible force-induced luminescence fiber stress sensors (flexible force-induced luminescence optical fiber and its preparation method and large-strain sensing application device (CN112213815A)) and force-induced luminescence fiber arrays (force-induced luminescence fiber array dynamic tactile perception system and its preparation method (CN118424524A)) are difficult to prepare structures inside a single waveguide, which limits their functional range. Summary of the Invention

[0005] The object of the present invention is to propose a flexible force-induced luminescence microstructured optical waveguide, which can be used in fields such as soft robots, medical diagnosis, and human motion monitoring.

[0006] The object of the present invention is achieved by at least one of the following technical solutions.

[0007] A flexible stress-induced luminescence microstructured optical waveguide includes an inner core, n stress-induced luminescence composite blocks closely attached to the inner core, a cladding that wraps the inner core and the n stress-induced luminescence composite blocks, and a protective layer coated on the surface of the cladding;

[0008] When the n stress-induced luminescence composite blocks are subjected to external stress, they generate fluorescence signals of different colors. The fluorescence signals are collected through the inner core and the cladding of the optical waveguide and transmitted along the inner core to the distal end for detection and demodulation. The sensing section corresponding to the force is determined by the demodulated color, and the magnitude of the corresponding force is determined by the intensity of the luminescence.

[0009] Furthermore, the stress-induced luminescence composite block is formed by compounding a stress-induced luminescence material with an organic elastomer. The stress-induced luminescence composite blocks that generate fluorescence signals of different colors include the same organic elastomer and stress-induced luminescence materials that emit different colors of light.

[0010] Furthermore, within the elastic deformation range, the stress-induced luminescence composite block does not require pre-excitation for luminescence and has recoverability. It can immediately restore its original luminescence performance after repeated mechanical stress deformations, and the luminescence intensity increases linearly with the increase of the applied stress.

[0011] Furthermore, the stress-induced luminescence composite block is closely attached to the inner core, and the stress-induced luminescence composite block can be closely attached to different sides of the inner core.

[0012] Furthermore, the refractive index of the inner core is greater than that of the cladding;

[0013] The cross-sectional size of the inner core is 0.1 - 3 mm × 0.3 - 5 mm, the external cross-sectional size of the cladding is 0.3 - 5 mm × 0.5 - 7 mm, the side length size of the stress-induced luminescence composite block is 0.1 - 5 mm, the thickness of the stress-induced luminescence composite block is 0.01 - 3 mm, and the length of the inner core and the cladding is 3 - 30 cm.

[0014] Furthermore, the fluorescence signals generated by the stress-induced luminescence composite block are transmitted in the inner core in the form of total internal reflection.

[0015] A method for preparing a flexible stress-induced luminescence microstructured optical waveguide includes the following steps:

[0016] S1. Use a first light-guiding precursor material to prepare the lower half of the cladding, and reserve vacancies on the upper surface of the lower half of the cladding for placing stress-induced luminescence composite blocks that emit different colors of light;

[0017] S2. Prepare stress-induced luminescence composite blocks that generate fluorescence signals of different colors;

[0018] S3. Place the stress-induced luminescence composite blocks that generate fluorescence signals of different colors in the vacancies on the upper surface of the lower half of the cladding;

[0019] S4. Prepare the inner core using a second light guiding precursor material in the lower half cladding, and make the photoluminescence composite block closely adhere to the inner core;

[0020] S5. Prepare the upper half cladding using the first light guiding precursor material, and combine the upper half cladding and the lower half cladding into one body to obtain a cladding that wraps the inner core and the photoluminescence composite block, forming a core-cladding structure. Apply a protective layer on the outer surface of the cladding to obtain a flexible photoluminescence microstructured optical waveguide.

[0021] Further, the refractive index of the second light guiding precursor material is greater than that of the first light guiding precursor material.

[0022] Further, in step S1, an organic elastomer material precursor solution with a refractive index of 1.3 - 1.5 is used as the first light guiding precursor material and injected into the first mold. When the first light guiding precursor material is thermosetting, it is cured at 20 - 150 °C for 1 - 5 hours to obtain the lower half cladding.

[0023] Further, in step S2, the organic elastomer material precursor solution is mixed with the photoluminescence material, and the range of the mixing mass ratio is 1:2 - 4:1. After stirring evenly to obtain a mixed material, it is poured into the second mold for curing. When the mixed material is thermosetting, it is cured at 20 - 150 °C for 1 - 5 hours to obtain the photoluminescence composite block.

[0024] Further, in step S3, the photoluminescence composite block is dipped in the first light guiding precursor material and placed in the reserved space on the upper surface of the lower half cladding. When the first light guiding precursor material is thermosetting, it is cured at 20 - 150 °C for 1 - 5 hours.

[0025] Further, in step S4, the lower half cladding with the photoluminescence composite block placed therein is put into the third mold, and an organic elastomer material precursor solution with a refractive index of 1.4 - 1.65 is injected as the second light guiding precursor material. When the second light guiding precursor material is thermosetting, it is cured at 20 - 150 °C for 1 - 5 hours. After curing, it is demolded to prepare the inner core, and make the photoluminescence composite block closely adhere to the inner core.

[0026] Further, in step S5, the lower half cladding with the inner core is put into the fourth mold, and the first light guiding precursor material is poured in and cured under the same conditions as curing the lower half cladding to prepare the upper half cladding, and make the upper half cladding and the lower half cladding combine into one body to obtain a cladding that wraps the inner core and the photoluminescence composite block. Finally, a protective layer is applied on the outer surface of the cladding to obtain a flexible photoluminescence microstructured optical waveguide.

[0027] A stress sensing system based on a flexible force-induced luminescence microstructure optical waveguide, comprising a flexible force-induced luminescence microstructure optical waveguide, an optical signal detection unit and a signal processing unit;

[0028] The input end of the optical signal detection unit is directly connected to the optical signal output end of the flexible force-induced luminescence microstructure optical waveguide; the output end of the optical signal detection unit is directly or remotely connected to the signal processing unit to transmit the optical signal to the signal processing unit.

[0029] The optical signal detection unit includes photodetectors such as a CCD camera, a color sensor, and a photomultiplier tube;

[0030] When the force-induced luminescence composite block in the flexible force-induced luminescence microstructure optical waveguide is subjected to different external stresses, the signal processing unit reflects the position and magnitude of the stress point.

[0031] Furthermore, when subjected to different external stresses, the force-induced luminescence composite block emits different force-induced fluorescence signals, which are transmitted to the input end of the optical signal detection unit through total internal reflection in the inner core, and then the optical signal detection unit uses a wireless communication module to transmit the signal to the signal processing unit. By analyzing the RGB intensity data and further data processing, the emitted color can be demodulated by converting it into CIE chromaticity coordinates to determine the stress position, and at the same time, the magnitude of the external force can be accurately quantified according to the change in the magnitude of the force-induced fluorescence signal.

[0032] In summary, compared with the prior art, the present invention has the following advantages and beneficial effects:

[0033] 1. The present invention uses an organosilicon elastomer material to prepare a stress sensor for a flexible force-induced luminescence microstructure optical waveguide, which has better biocompatibility, high stability, and good durability, and is suitable for applications in the fields of wearable devices, biological medicine, and sports monitoring.

[0034] 2. The present invention directly converts stress into optical signals using force-induced luminescence materials, without the need for additional light sources and complex circuits, making the device miniaturized.

[0035] 3. For the stress sensing based on the flexible force-induced luminescence microstructure optical waveguide developed by the present invention, the used optical signal detection unit can wirelessly transmit data, can be integrated in a closed wearable device, and the signal demodulation method is simple.

[0036] 4. The structure of the present invention has a complete core, which can effectively reduce the waveguide loss during waveguide deformation and achieve distributed sensing when multiple positions are pressed simultaneously.

[0037] 5. The preparation method of the present invention can prepare different structures in the optical waveguide by customizing different molds to meet different purposes. Description of the Drawings

[0038] Figure 1 It is a schematic structural diagram of the stress sensing system based on the flexible force-induced luminescence microstructured optical waveguide in Embodiment 3 of the present invention.

[0039] Figure 2 It is a schematic diagram of the manufacturing process of the flexible force-induced luminescence microstructured optical waveguide in Embodiment 2 of the present invention.

[0040] Figure 3 It is a schematic structural diagram of the flexible force-induced luminescence microstructured optical waveguide in Embodiment 1 of the present invention. Detailed implementation manners

[0041] The following specifically describes the specific implementation of the present invention in conjunction with the drawings and embodiments, but does not limit the present invention.

[0042] Embodiment 1:

[0043] In this embodiment, a flexible force-induced luminescence microstructured optical waveguide, as Figure 3 and Figure 1 shown, includes a rectangular inner core 1, three force-induced luminescence composite blocks, a rectangular strip-shaped cladding 2 that wraps the inner core 1 and the three force-induced luminescence composite blocks, and a protective layer coated on the surface of the cladding 2;

[0044] The three force-induced luminescence composite blocks generate fluorescent signals of different colors under external stress. The fluorescent signals are collected by the inner core 1 and the cladding 2 of the optical waveguide and transmitted along the inner core 1 to the distal end for detection and demodulation. The stressed sensing section is determined by the demodulated color, and the magnitude of the applied force is determined by the magnitude of the luminescence intensity.

[0045] Furthermore, the force-induced luminescence composite block is composed of a force-induced luminescence material and an organic elastomer. The force-induced luminescence composite blocks that generate fluorescent signals of different colors include the same organic elastomer and force-induced luminescence materials that emit different colors of light. The force-induced luminescence material does not require continuous excitation from a power source or a light source.

[0046] Furthermore, within the elastic deformation range, the force-induced luminescence composite block does not require pre-excitation for luminescence, has recoverability, and can immediately restore its original luminescence performance after being repeatedly deformed by mechanical stress. The luminescence intensity increases linearly with the increase of the applied stress.

[0047] As Figure 3 shown, in this embodiment, the first force-induced luminescence composite block 3, the second force-induced luminescence composite block 4, and the third force-induced luminescence composite block 5 are closely attached to the inner core 1.

[0048] Furthermore, the refractive index of the inner core 1 is greater than that of the cladding 2;

[0049] In this embodiment, in the flexible force-induced luminescence microstructured optical waveguide, the refractive index of the inner core 1 is 1.46, the refractive index of the cladding 2 is 1.41, the cross-sectional size of the inner core 1 is 1 mm × 3 mm, the outer cross-sectional size of the cladding 2 is 3 mm × 5 mm, the side length of the first force-induced luminescence composite block 3, the second force-induced luminescence composite block 4, and the third force-induced luminescence composite block 5 is 3 mm, the thickness of the first force-induced luminescence composite block 3, the second force-induced luminescence composite block 4, and the third force-induced luminescence composite block 5 is 0.5 mm, the length of the inner core 1 and the cladding 2 is 6 cm, the distance between the first force-induced luminescence composite block 3, the second force-induced luminescence composite block 4, and the third force-induced luminescence composite block 5 is 1.5 cm, and the thickness of the protective layer is 0.5 mm. It can efficiently collect the force-induced luminescence signals generated by the force-induced luminescence sensing layer and transmit them over a relatively long distance.

[0050] In this embodiment, octamethylcyclotetrasiloxane (LS-6946) is selected for the inner core 1, polydimethylsiloxane (PDMS) is used for the cladding 2, and the first force-induced luminescence composite block 3, the second force-induced luminescence composite block 4, and the third force-induced luminescence composite block 5 are made of a composite of a force-induced luminescence material and polydimethylsiloxane. The force-induced luminescence material is an elastic force-induced luminescence material, that is, within the range of matrix elastic deformation, its luminescence is recoverable and the luminescence intensity increases with the increase of stress. In this embodiment, the first force-induced luminescence composite block 3, the second force-induced luminescence composite block 4, and the third force-induced luminescence composite block 5 are respectively selected with the force-induced luminescence materials ZnS:Cu + 、ZnS:Cu 2+ and ZnS:Mn 2+ / Cu 2+ . These three materials emit blue light with a wavelength of 480 nm, green light with a wavelength of 520 nm, and yellow light with wavelengths of 520 nm and 580 nm respectively when stressed. These force-induced luminescence materials are compounded with the organic elastomer polydimethylsiloxane (PDMS) to form rectangular blocks and are located in the cladding 2.

[0051] Furthermore, the fluorescence signals generated by the force-induced luminescence composite blocks are transmitted in the inner core 1 in the form of total internal reflection.

[0052] Example 2:

[0053] A method for preparing a flexible force-induced luminescence microstructured optical waveguide, as shown in Figure 2 and Figure 3 , includes the following steps:

[0054] S1. Use the first light-guiding precursor material to prepare the lower half of the cladding 2-1, and reserve vacancies on the upper surface of the lower half of the cladding 2-1 for placing force-induced luminescence composite blocks that emit different colors of light;

[0055] Inject the precursor solution of the organic elastomer material with a refractive index of 1.3 - 1.5 as the first light - guiding precursor material into the first mold. When the first light - guiding precursor material is thermosetting, cure it at 20 - 150 °C for 1 - 5 hours to obtain the lower - half cladding 2 - 1;

[0056] In this embodiment, after mixing the precursors A and B of polydimethylsiloxane (PDMS) in a mass ratio of 10:1 evenly, inject them into a stainless - steel mold with an inner - wall size of 2 mm×5 mm×60 mm and a 1 mm×3 mm×60 mm protrusion, and scrape off the overflow. Place the above - mentioned mold in an oven and cure it at 80 °C for 60 minutes. After demolding, obtain the lower - half cladding 2 - 1 of the flexible force - induced luminescence micro - structure optical waveguide;

[0057] S2. Prepare force - induced luminescence composite blocks that generate fluorescent signals of different colors;

[0058] Mix the precursor solution of the organic elastomer material with the force - induced luminescence material. The range of the mixing mass ratio is 1:2 - 4:1, and stir evenly to obtain a mixed material. Pour the mixed material into the second mold and cure it. When the mixed material is thermosetting, cure it at 20 - 150 °C for 1 - 5 hours to obtain the force - induced luminescence composite block;

[0059] In this embodiment, after mixing the precursors A and B of polydimethylsiloxane (PDMS) in a mass ratio of 10:1 evenly, add the force - induced luminescence material powders ZnS:Cu + 、ZnS:Cu 2+ 、ZnS:Mn 2+ / Cu 2+ respectively. The powders and polydimethylsiloxane (PDMS) are mixed evenly in a mass ratio of 3:1, injected into a stainless - steel mold with an inner - wall size of 3 mm×3 mm×0.5 mm, scrape off the overflow, and place it in an oven to cure at 80 °C for 60 minutes to obtain 3 force - induced luminescence composite blocks that generate fluorescent signals of different colors;

[0060] S3. Place the force - induced luminescence composite blocks that generate fluorescent signals of different colors in the vacancies on the upper surface of the lower - half cladding 2 - 1;

[0061] Dip the force - induced luminescence composite block in the first light - guiding precursor material and put it into the reserved vacancies on the upper surface of the lower - half cladding 2 - 1. When the first light - guiding precursor material is thermosetting, cure it at 20 - 150 °C for 1 - 5 hours.

[0062] In this embodiment, three kinds of mechanoluminescent composite blocks that generate fluorescent signals of different colors are respectively dipped into polydimethylsiloxane (PDMS) obtained by mixing precursor A and B in a mass ratio of 10:1, and placed into the vacancies reserved on the upper surface of the lower cladding 2-1, and then placed in an oven and cured at 80 °C for 60 minutes.

[0063] S4. Use a second light-guiding precursor material to prepare the inner core 1 in the lower cladding 2-1, and make the mechanoluminescent composite block closely adhere to the inner core 1.

[0064] The refractive index of the second light-guiding precursor material is greater than that of the first light-guiding precursor material.

[0065] Put the lower cladding 2-1 with the mechanoluminescent composite block placed therein into a third mold, inject an organic elastomer material precursor solution with a refractive index of 1.4-1.65 as the second light-guiding precursor material. When the second light-guiding precursor material is thermosetting, cure it at 20-150 °C for 1-5 hours, and demold after curing to prepare the inner core 1, and make the mechanoluminescent composite block closely adhere to the inner core 1.

[0066] In this embodiment, put the lower cladding 2-1 with the mechanoluminescent composite block placed therein into a mold made of stainless steel with an inner wall size of 2 mm × 5 mm × 60 mm, mix the precursors A and B of octamethylcyclotetrasiloxane (LS-6946) evenly in a ratio of 1:1, inject them into the mold, scrape off the overflow part, put it into a vacuum chamber, maintain a temperature below 20 °C and evacuate for 20 min to remove air bubbles, and then place it in an oven and cure at 65 °C for 20 minutes to prepare the inner core 1, and make the mechanoluminescent composite block closely adhere to the inner core 1.

[0067] S5. Use the first light-guiding precursor material to prepare the upper cladding 2-2, and make the upper cladding 2-2 and the lower cladding 2-1 integrated to obtain the cladding 2 that wraps the inner core 1 and the mechanoluminescent composite block, forming a core-cladding structure, and apply a protective layer on the outer surface of the cladding 2 to obtain a flexible mechanoluminescent microstructured optical waveguide.

[0068] Put the lower cladding 2-1 with the inner core 1 into a fourth mold, pour in the first light-guiding precursor material, and cure it under the same conditions as curing the lower cladding 2-1 to prepare the upper cladding 2-2, and make the upper cladding 2-2 and the lower cladding 2-1 integrated to obtain the cladding 2 that wraps the inner core 1 and the mechanoluminescent composite block. Finally, apply a protective layer on the outer surface of the cladding 2 to obtain a flexible mechanoluminescent microstructured optical waveguide.

[0069] In this embodiment, after demoulding, the lower half cladding 2-1 with the inner core 1 is placed into a stainless steel mold with inner wall dimensions of 3 mm×5 mm×60 mm. After the precursors A and B of polydimethylsiloxane (PDMS) are uniformly mixed at a mass ratio of 10:1, they are injected into the mold, the overflow part is scraped off, and then it is placed in an oven and cured at 80 °C for 60 minutes to prepare the upper half cladding 2-2, and the upper half cladding 2-2 is integrated with the lower half cladding 2-1 to obtain the cladding 2 that wraps the inner core 1 and the force-induced luminescence composite block. Finally, a protective layer is coated on the outer surface of the cladding 2 to obtain a complete flexible force-induced luminescence microstructured optical waveguide.

[0070] Example 3:

[0071] In this embodiment, a stress sensing system based on a flexible force-induced luminescence microstructured optical waveguide, as Figure 1 shown, includes a flexible force-induced luminescence microstructured optical waveguide 6, an optical signal detection unit 7, and a signal processing unit 8;

[0072] The input end of the optical signal detection unit 7 is directly connected to the optical signal output end of the flexible force-induced luminescence microstructured optical waveguide 6; the output end of the optical signal detection unit 7 is directly or remotely connected to the signal processing unit 8 to transmit the optical signal to the signal processing unit 8.

[0073] In this embodiment, a color sensor is used as the optical signal detection unit;

[0074] When the first force-induced luminescence composite block 3, the second force-induced luminescence composite block 4, and the third force-induced luminescence composite block 5 in the flexible force-induced luminescence microstructured optical waveguide 6 are subjected to different external stresses, the signal processing unit 8 reflects the position and magnitude of the stress application point.

[0075] In this embodiment, when no external force acts on the force-induced luminescence composite block, the color sensor has a fixed value. When different force-induced luminescence composite blocks are stressed, the polydimethylsiloxane (PDMS) doped with the force-induced luminescence materials ZnS:Cu + 、ZnS:Cu 2+ 、ZnS:Mn 2+ / Cu 2+ will emit blue, green, and yellow light respectively. The color sensor will receive the color signals of different lights and wirelessly transmit them to the signal processing unit, which are converted into CIE chromaticity coordinates, and the specific color of the light and the sensing area corresponding to the pressure can be demodulated; and as the pressure increases, the RGB intensity data of the color sensor will also linearly increase correspondingly, and the magnitude of the stress applied to the corresponding sensing area can be demodulated.

[0076] The above embodiments are the preferred embodiments of the present invention, but the embodiments of the present invention are not limited to the above embodiments. Any other changes, modifications, substitutions, combinations, and simplifications made without departing from the spirit and principle of the present invention shall be equivalent replacement methods and are all included in the protection scope of the present invention.

Claims

1. A flexible force-induced luminescence microstructured optical waveguide, characterized in that, It includes an inner core (1), n stress-induced luminescence composite blocks closely attached to the inner core (1), a cladding (2) that wraps the inner core (1) and the n stress-induced luminescence composite blocks, and a protective layer coated on the surface of the cladding (2); When the n stress-induced luminescence composite blocks are subjected to external stress, they generate fluorescence signals of different colors. The fluorescence signals are collected through the inner core (1) and the cladding (2) of the optical waveguide and transmitted along the inner core (1) to the distal end.

2. The flexible force-induced luminescence microstructural optical waveguide according to claim 1, characterized in that The stress-induced luminescence composite blocks that generate fluorescence signals of different colors include the same organic elastomer and stress-induced luminescence materials that emit different colors of light.

3. A flexible force-induced luminescence microstructured optical waveguide according to claim 1, wherein, Within the elastic deformation range, the stress-induced luminescence composite blocks can emit light without pre-excitation and have recoverability. They can restore their original luminescence performance after being repeatedly deformed by mechanical stress, and the luminescence intensity increases linearly with the increase of the applied stress.

4. A flexible force-induced luminescence microstructured optical waveguide according to claim 1, characterized in that, The stress-induced luminescence composite blocks are closely attached to the inner core (1).

5. A flexible force-induced luminescence microstructural optical waveguide according to claim 1, characterized in that, The refractive index of the inner core (1) is greater than that of the cladding (2).

6. The flexible force-induced luminescence microstructure optical waveguide according to claim 1, wherein, The fluorescence signals generated by the stress-induced luminescence composite blocks are transmitted in the inner core (1) in the form of total internal reflection.

7. A method for preparing a flexible force-induced luminescence microstructured optical waveguide according to any one of claims 1 to 6, characterized in that, It includes the following steps: S1. Prepare the lower half of the cladding (2-1) using a first light-guiding precursor material. Vacancies are reserved on the upper surface of the lower half of the cladding (2-1) to place stress-induced luminescence composite blocks that emit different colors of light; S2. Prepare stress-induced luminescence composite blocks that generate fluorescence signals of different colors; S3. Place the stress-induced luminescence composite blocks that generate fluorescence signals of different colors in the vacancies on the upper surface of the lower half of the cladding (2-1); S4. Prepare the inner core (1) in the lower half of the cladding (2-1) using a second light-guiding precursor material, and make the stress-induced luminescence composite blocks closely attached to the inner core (1); S5. Prepare the upper half of the cladding (2-2) using the first light-guiding precursor material, and make the upper half of the cladding (2-2) integrated with the lower half of the cladding (2-1) to obtain the cladding (2) that wraps the inner core (1) and the stress-induced luminescence composite blocks, forming a core-cladding structure. Apply a protective layer on the outer surface of the cladding (2) to obtain a flexible stress-induced luminescence microstructured optical waveguide.

8. The method for preparing a flexible force-induced luminescence microstructured optical waveguide according to claim 7, characterized in that, The refractive index of the second light-guiding precursor material is greater than that of the first light-guiding precursor material.

9. A stress sensing system based on a flexible force-induced luminescence microstructured optical waveguide, characterized in that, It includes a flexible stress-induced luminescence microstructured optical waveguide (6), an optical signal detection unit (7), and a signal processing unit (8) according to any one of claims 1 to 6; The input end of the optical signal detection unit (7) is directly connected to the optical signal output end of the flexible stress-induced luminescence microstructured optical waveguide (6); the output end of the optical signal detection unit (7) is directly or remotely connected to the signal processing unit (8) to transmit the optical signal to the signal processing unit (8). When the stress-induced luminescence composite blocks in the flexible stress-induced luminescence microstructured optical waveguide (6) are subjected to different external stresses, the signal processing unit (8) responds to the position and magnitude of the stressed point.

10. The stress sensing system based on a flexible force-induced luminescence microstructured optical waveguide according to claim 9, characterized in that, When subjected to different external stresses, the force-induced luminescence composite block emits different force-induced fluorescence signals, which are transmitted to the input end of the optical signal detection unit (7) in the inner core (1) through total internal reflection, and then the optical signal detection unit (7) delivers the signals to the signal processing unit (8). By analyzing the RGB intensity data and further processing the data, the color of the emitted light is demodulated into CIE chromaticity coordinates to determine the stress position. At the same time, the magnitude of the external force is quantified according to the magnitude of the change in the force-induced fluorescence signal.

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