Printed fiber optic sensor decoupled from temperature strain and method of spray deposition manufacturing and applications

Abstract

The application belongs to the technical field of flexible sensor manufacturing, and discloses a printed optical fiber sensor capable of decoupling temperature strain, a jet printing manufacturing method and application. The printed optical fiber sensor comprises an optical fiber, a temperature-sensitive sensing structure and a force-sensitive sensing structure which are distributedly embedded in the optical fiber. The material of the temperature-sensitive sensing structure is temperature-sensitive fluorescent material, and the material of the force-sensitive sensing structure is force-sensitive fluorescent material. The temperature-sensitive sensing structure and the force-sensitive sensing structure are used for detecting information of external temperature and strain and emitting corresponding fluorescence. The printed optical fiber sensor realizes in-situ detection of external temperature and strain and decoupling of temperature strain according to the lifetime information and light intensity of the fluorescence. The temperature-sensitive fluorescent material and the force-sensitive fluorescent material are excited to scatter, and then the in-situ measurement of external temperature and strain and the decoupling of temperature strain are realized by monitoring the fluorescence lifetime information and light intensity of the fluorescence.

Description

Technical Field

[0001] This invention belongs to the field of flexible sensing manufacturing technology, and more specifically, relates to a printed fiber optic sensor with decoupled temperature strain and its printing manufacturing method and application. Background Technology

[0002] Fiber optic sensors transmit changes in external signals via optical signal propagation. Compared to ordinary electrical sensors, fiber optic sensors are unaffected by external electromagnetic interference and offer high sensitivity and fast response speeds, making them promising for applications in extreme conditions such as aircraft skin signal acquisition, surgical robot radio frequency sensing, and engine performance monitoring. A fiber optic sensor converts external stimuli into optical signals and transmits them through optical fibers. When external conditions change, such as temperature, strain, gas concentration, or humidity, corresponding characteristics of the optical signal transmitted within the fiber optic cable also change, such as light intensity, wavelength, frequency, and phase. These changes are then demodulated by a spectrometer at the fiber optic backend to obtain the measured parameter.

[0003] Fiber Bragg gratings are periodic grating structures prefabricated inside silica optical fibers. They can shift the grating period when temperature or strain changes, thereby selectively reflecting changes in the wavelength of light and enabling the sensing of external temperature or strain signals. However, considering the complexity of the working environment of fiber optic sensors, such as the surface of intelligent skin of aircraft, there are usually synchronous changes in temperature and strain signals. Traditional Bragg gratings cannot simultaneously identify the difference between the two signals and cannot decouple the two stimulus signals.

[0004] To address the inability of current fiber Bragg grating sensors to achieve temperature-strain decoupling, several solutions have been proposed in different aspects. For example, patent CN112945129A proposes a fiber optic sensor that simultaneously monitors temperature and strain. It uses a micro-fiber junction as the temperature sensor and a cascaded Fabry-Perot cavity with a long-period fiber Bragg grating as the strain sensor. This method uses different structures to monitor temperature and strain, resulting in complex structures and difficult fabrication. Only one temperature and strain sensor can be placed on a single fiber, making distributed temperature and strain sensing impossible. Another example is patent CN112212915A, which discloses a flexible fiber Bragg grating sensor for completely synchronous temperature and strain measurement. This sensor fuses a fiber Bragg grating temperature sensor and a fiber Bragg grating strain sensor to different locations on the fiber and uses flexible sleeve encapsulation and temperature compensation to achieve distributed temperature and strain measurement. However, this method cannot achieve in-situ monitoring of temperature and strain, and the compensation difficulty increases with the number of sensors.

[0005] In recent years, fiber optic fluorescence sensors have attracted attention as a means of monitoring external signals using the principle of fluorescence. Existing fiber optic fluorescence sensors use a pump light source as the excitation source, which stimulates the fluorescent material to emit light through incident optical fiber. Changes in external signals are determined by detecting fluorescence intensity, decay time, etc. For example, the fiber optic fluorescence temperature sensors proposed in patents CN101726372A and CN101216355A. However, current fiber optic fluorescence sensors are limited by manufacturing processes, and can only place the fluorescent material at the end of the optical fiber, thus losing the advantage of distributed measurement and failing to achieve simultaneous in-situ monitoring of temperature and strain.

[0006] In summary, existing fiber-optic-based sensors all rely on microstructures designed at different locations within the fiber to respond to external temperature or strain. They cannot simultaneously achieve in-situ monitoring and distributed measurement of both temperature and strain, and typically require complex fabrication processes involving multiple UV exposures and multi-component fusion splicing. Therefore, there is an urgent need to propose a fiber-optic-based in-situ temperature and strain monitoring sensor that can achieve in-situ monitoring of temperature and strain using a relatively simple fabrication process. Summary of the Invention

[0007] To address the above-mentioned deficiencies or improvement needs of existing technologies, this invention provides a decoupled temperature-strain printed fiber optic sensor and its printing manufacturing method and application. It utilizes stimulated scattering of temperature-sensitive and force-sensitive fluorescent materials, and then monitors the fluorescence lifetime information and light intensity of the fluorescence to achieve in-situ measurement of external temperature and strain, thereby realizing the decoupling of temperature and strain.

[0008] To achieve the above objectives, according to one aspect of the present invention, a printed fiber optic sensor capable of decoupling temperature and strain is provided. The printed fiber optic sensor includes an optical fiber, a temperature-sensitive sensing structure and a force-sensitive sensing structure distributed and embedded on the optical fiber; wherein the material of the temperature-sensitive sensing structure is a temperature-sensitive fluorescent material, and the material of the force-sensitive sensing structure is a force-sensitive fluorescent material. The temperature-sensitive sensing structure and the force-sensitive sensing structure are used to detect information on external temperature and strain and emit corresponding fluorescence. The printed fiber optic sensor realizes in-situ detection of external temperature and strain and decoupling of temperature and strain based on the lifetime information and light intensity of the fluorescence.

[0009] Furthermore, when a pump light source laser passes through the temperature-sensitive sensing structure and the force-sensitive sensing structure, the temperature-sensitive sensing structure and the force-sensitive sensing structure emit fluorescence of different wavelengths.

[0010] Furthermore, the cladding and sheathing of the optical fiber corresponding to the regions of the temperature-sensitive sensing structure and the force-sensitive sensing structure are removed, leaving only the fiber core.

[0011] Furthermore, the optical fiber includes a fiber core, a cladding covering the outer peripheral surface of the fiber core, and a coating covering the outer peripheral surface of the cladding; the optical fiber has a plurality of distributed receiving slots, the receiving slots penetrating the coating and the cladding.

[0012] Furthermore, the temperature-sensitive sensing structure and the force-sensitive sensing structure are arranged in a group, and the temperature-sensitive sensing structure and the thermal sensing structure in the same group are respectively arranged in two adjacent receiving slots.

[0013] Furthermore, the temperature-sensitive sensing structure and the force-sensitive sensing structure are arranged in a group, and the temperature-sensitive sensing structure and the thermal sensing structure in the same group are arranged at intervals in the same receiving tank.

[0014] Furthermore, the printed fiber optic sensor also includes a pump source, a fiber coupler, a filter, a photodetector, a signal amplifier, and a processing module. The pump source emits laser light, which is transmitted to the fiber optic cable via the fiber coupler and then to the temperature-sensitive and force-sensitive sensing structures. The fluorescence generated by the temperature-sensitive and force-sensitive sensing structures propagates in the opposite direction and is transmitted to the filter via the fiber coupler. The filter filters the received fluorescence signal, extracts the fluorescence information to be analyzed, and transmits it to the photodetector. The photodetector converts the received fluorescence into an electrical signal and transmits it to the signal amplifier. The signal amplifier amplifies the received electrical signal and transmits it to the processing module. The processing module analyzes and processes the received electrical signal to achieve in-situ detection of external temperature and strain and decoupling of temperature and strain.

[0015] Furthermore, fluorescence lifetime is only related to temperature. By monitoring the fluorescence decay rate, i.e., the change in fluorescence lifetime, using a photodetector, the change in external temperature can be determined. The processing module uses the correlation between fluorescence lifetime and temperature to calculate the corresponding external temperature; the correlation between fluorescence lifetime and temperature is as follows: Where a, b, k, and ΔE are constants, and T is the ambient temperature.

[0016] The present invention also provides a method for inkjet printing manufacturing of a decoupled temperature strain printed fiber optic sensor as described above, the method comprising the following steps:

[0017] (1) Prepare multiple distributed receiving slots on the optical fiber;

[0018] (2) Using temperature-sensitive material and force-sensitive material as raw materials, respectively, temperature-sensitive sensing structure and thermal-sensitive sensing structure are prepared in the receiving tank by electrohydrodynamic inkjet printing, thereby obtaining the printed fiber optic sensor.

[0019] The present invention also provides an application of the decoupled temperature strain printed fiber optic sensor described above in aircraft skin signal acquisition, surgical robot radio frequency sensing, and engine performance monitoring.

[0020] In summary, compared with the prior art, the decoupled temperature strain printed fiber optic sensor and its manufacturing method and application provided by this invention have the following advantages:

[0021] 1. Decoupling and measurement of temperature and strain: By placing temperature-sensitive and force-sensitive fluorescent materials at different positions in an optical fiber, and utilizing the characteristics that the decay lifetime and intensity of different fluorescence are sensitive to temperature and strain respectively, temperature and strain can be measured separately, solving the problem that ordinary optical fiber sensors cannot achieve temperature and strain decoupling.

[0022] 2. High-resolution printing technology was used to realize the patterned printing of fluorescent materials on the surface of optical fibers, and the fabrication of temperature strain sensors on the surface of 125μm optical fibers was achieved.

[0023] 3. Distributed printing manufacturing of fiber optic sensors was realized. By utilizing the cooperation of a wire feeding motor, a wire take-up motor, and dual rotary motors, the fabrication of long-distance distributed surface sensors for optical fibers was achieved, solving the problem of printing and manufacturing long-distance distributed optical fiber sensors.

[0024] 4. This invention achieves high-intensity fluorescence sensing and optical transmission within the cladding. The pump light is transmitted within the fiber cladding, directly transmitting the pump laser to the surface of the fluorescent material, achieving direct contact between the fluorescent material and the pump light, thereby improving fluorescence efficiency and fluorescence intensity.

[0025] 5. The fluorescence lifetime of the material is only related to the ambient temperature of the optical fiber, and is independent of the strain generated in the optical fiber, and is not affected by the intensity fluctuation of the pump light source; using fluorescence lifetime to indirectly characterize temperature changes has a simple measurement system structure and can greatly improve the accuracy of temperature measurement. Attached Figure Description

[0026] Figure 1 This is a schematic diagram of the temperature strain fiber optic sensing structure provided by the present invention;

[0027] Figure 2 This is a schematic diagram of the structure of a printed fiber optic sensor capable of decoupling temperature strain provided by the present invention;

[0028] Figure 3 yes Figure 1 Flowchart of the fabrication process of the temperature strain fiber optic sensing structure in the image;

[0029] Figure 4 It is the preparation Figure 1 A schematic diagram of the process of the temperature strain fiber optic sensing structure in the image.

[0030] Figure 5 yes Figure 1 The printing fabrication effect of the temperature strain fiber optic sensing structure in the image.

[0031] In all the accompanying drawings, the same reference numerals are used to denote the same elements or structures, wherein: 1-temperature-sensitive sensing structure, 2-force-sensitive sensing structure, 3-coating layer, 4-cladding layer, 5-fiber core, 6-feed motor, 7-optical fiber, 8-left rotary motor, 9-nozzle, 10-right rotary motor, 11-take-up motor, a-pump source laser, b-fluorescence of temperature-sensitive material, c-fluorescence of force-sensitive material. Detailed Implementation

[0032] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention. Furthermore, the technical features involved in the various embodiments of this invention described below can be combined with each other as long as they do not conflict with each other.

[0033] Please see Figure 1 This invention provides a decoupled temperature strain printed fiber optic sensor and its manufacturing method and application. Utilizing the advantages of in-situ, high efficiency, and low cost of printing technology, the temperature strain sensor can be manufactured in situ, enabling synchronous measurement of external temperature strain. Printing, as an additive manufacturing technology, offers advantages such as in-situ manufacturing, high efficiency, high scalability, and material saving. Distributed temperature-sensitive sensing structures 1 and 2 are fabricated on an optical fiber 7 using printing technology. Pump light enters the optical fiber 7 and undergoes stimulated scattering through the temperature-sensitive sensing structures 1 and 2, respectively. By monitoring the fluorescence intensity and lifetime information, in-situ online measurement of external strain and temperature can be achieved, realizing the decoupling of temperature strain.

[0034] The printed fiber optic sensor includes an optical fiber 7, a temperature-sensitive sensing structure 1, and a force-sensitive sensing structure 2 distributedly embedded on the optical fiber 7. The temperature-sensitive sensing structure 1 is made of a temperature-sensitive fluorescent material, and the force-sensitive sensing structure 2 is made of a force-sensitive fluorescent material. The temperature-sensitive sensing structure 1 and the force-sensitive sensing structure 2 are used to detect external temperature and strain information and emit corresponding fluorescence. The printed fiber optic sensor achieves in-situ detection of external temperature and strain and decoupling of temperature and strain based on the lifetime information and light intensity of the fluorescence. The temperature-sensitive sensing structure 1 and the temperature-sensitive sensing structure can also be referred to as a temperature sensor and a strain sensor, respectively.

[0035] When the laser emitted by the pump light source is transmitted through the fiber cladding 4 to the temperature-sensitive sensing structure 1 and the force-sensitive sensing structure 2, the temperature-sensitive sensing structure 1 and the force-sensitive sensing structure 2 will emit fluorescence of different wavelengths. By utilizing the fluorescence decay lifetime and intensity information of the two wavelengths to detect the external temperature and strain, the detection of the external temperature and strain can be realized.

[0036] The cladding layer and cladding 4 of the region of the optical fiber 7 corresponding to the temperature-sensitive sensing structure 1 and the force-sensitive sensing structure 2 are removed, leaving only the fiber core 5. After the pump laser enters the optical fiber 7, it will be stimulated scattering through the temperature-sensitive sensing structure 1 and the force-sensitive sensing structure 2 respectively. By monitoring the fluorescence intensity and fluorescence lifetime information, in-situ online measurement of external temperature and strain based on the optical fiber 7 and decoupling of temperature and strain can be achieved.

[0037] The optical fiber 7 includes a fiber core 5, a cladding 4 covering the outer periphery of the fiber core 5, and a coating layer 3 covering the outer periphery of the cladding 4. The optical fiber 7 has multiple distributed receiving slots, which penetrate the coating layer 3 and the cladding 4. The temperature-sensitive sensing structure 1 and the force-sensitive sensing structure 2 are grouped together, with the temperature-sensitive sensing structure 1 and the thermal sensing structure within the same group respectively disposed in two adjacent receiving slots. In another embodiment, the temperature-sensitive sensing structure 1 and the thermal sensing structure are spaced apart within the same receiving slot.

[0038] When the molecules of the temperature-sensitive fluorescent material and the force-sensitive fluorescent material are excited by a narrow-band pulsed light source, they absorb photon energy, causing the fluorescent material molecules to transition from the ground state to the excited state. The excited state molecules are unstable. When the molecules return from the lowest vibrational energy level of the excited state to the ground state, the excess energy is emitted in the form of photons, which results in fluorescence.

[0039] The temperature-sensitive fluorescent materials include, but are not limited to, sulfide fluorescent materials, zinc oxide (ZnO) fluorescent materials, silicate fluorescent materials, tungstate fluorescent materials, rare earth fluorescent materials, and organic fluorescent materials. The sulfides include, but are not limited to, Cu, Ag, and Au-doped zinc sulfide (ZnS), cadmium sulfide (CdS), barium sulfide (BaS), and calcium sulfide (CaS). The silicate fluorescent materials include, but are not limited to, Mn-doped Zn₂SO₄. The tungstate fluorescent materials include, but are not limited to, calcium tungstate (CaSO₄), cadmium tungstate (CdWO₄), and zinc tungstate (ZnWO₄). The organic fluorescent materials include, but are not limited to, Cs₂SnCl₆, Rb₂SnCl₆, and other organic fluorescent materials.

[0040] Specifically, when the external temperature rises, molecular vibrations intensify, the quenching rate of fluorescent photons accelerates, and the fluorescence lifetime shortens. The photon quenching rate is proportional to the external temperature and depends only on temperature; it is independent of factors such as the intensity of the excitation source, fiber vibration, and strain. By monitoring changes in the fluorescence decay rate, i.e., the fluorescence lifetime, using a photodetector, the change in external temperature can be determined. The relationship between fluorescence lifetime and temperature is as follows: Where a, b, k, and ΔE are constants. T The ambient temperature.

[0041] The force-sensitive fluorescent materials include, but are not limited to, group II-IV nitride fluorescent materials. These group II-IV nitride fluorescent materials include, but are not limited to, indium gallium nitride (InGaN), gallium nitride (GaN), and ZnSe-based quantum well materials such as ZnSe / Zn 1-x Cd x Specifically, when strain is applied to the optical fiber, the greater the applied strain, the lower the radiative transition probability of the fluorescent material, the weaker the luminescence intensity, and the lower the peak energy at the fluorescence peak. By monitoring the fluorescence intensity change at the corresponding wavelength using a photodetector, the change in optical fiber strain can be indirectly determined.

[0042] In another embodiment, the temperature-sensitive fluorescent material is Cs₂SnCl₆, and the force-sensitive fluorescent material is ZnSe / Zn 1- x Cd x Se quantum well superlattice material. When the pump source laser c emitted by the pump source is transmitted to the temperature-sensitive sensing structure 1 and the force-sensitive sensing structure 2 through the fiber cladding, the fluorescent materials of the temperature-sensitive sensing structure 1 and the force-sensitive sensing structure 2 will emit force-sensitive material fluorescence a and temperature-sensitive material fluorescence b of different wavelengths. By utilizing the characteristics that the decay lifetime and intensity of the two fluorescences are sensitive to the external temperature and strain respectively, the monitoring of the external temperature and strain can be realized.

[0043] Please see Figure 2The printed fiber optic sensor further includes a pump source, a fiber coupler, a filter, a photodetector, a signal amplifier, and a processing module. The pump source emits laser light, which is transmitted to the fiber optic cable via the fiber coupler and then passes through the temperature-sensitive sensing structure 1 and the force-sensitive sensing structure 2. The fluorescence generated by these two structures propagates in the opposite direction and is transmitted through the fiber coupler to the filter. The filter filters the received fluorescence signal, extracts fluorescence information at a specific wavelength to be analyzed, and transmits it to the photodetector. The photodetector converts the received fluorescence into an electrical signal, which is then transmitted to the signal amplifier. The signal amplifier amplifies the received electrical signal and transmits it to the processing module. The processing module analyzes and processes the received electrical signal to achieve in-situ detection of external temperature and strain, and decoupling of temperature and strain.

[0044] In this embodiment, the processing module is a CPU, which realizes in-situ detection of external temperature and strain and decoupling of temperature and strain based on the received fluorescence lifetime information and light intensity.

[0045] The pump source includes, but is not limited to, white LEDs, ultraviolet lasers, and infrared lasers. The photodetector includes, but is not limited to, photomultiplier tubes, photodiodes, and spectrometers. The fiber optic coupler is a 1×2 fiber optic coupler, responsible for inputting the laser from the pump source into the fiber optic sensor and simultaneously guiding the fluorescence emitted by the fiber optic sensor to a filter for filtering. The temperature-sensitive sensing structure 1 and the force-sensitive sensing structure 2 are distributed along the entire fiber, collecting information on changes in external temperature and strain, and transmitting this information back to the coupler in the form of fluorescence. The fiber optic cable includes, but is not limited to, single-mode fiber and multimode fiber, used to conduct the laser from the pump source and the fluorescence signal emitted by the sensor.

[0046] In this embodiment, the pump source is an ultraviolet laser source, the photodetector is a spectrometer, and the optical fiber is a single-mode optical fiber used to transmit the laser from the pump source and the fluorescence signals emitted by the temperature sensing structure and the thermal sensing structure.

[0047] To improve measurement accuracy, an identical fiber can be placed outside the distributed sensing fiber as a comparison fiber. The comparison fiber is placed in an environment where the temperature and strain remain constant. By comparing the return values ​​of the fluorescence signals from the two fibers, the measurement accuracy of temperature and strain can be improved.

[0048] The filter filters the broadband information emitted by the fluorescence, extracts the narrowband wavelength information to be analyzed, and transmits it to the CPU module for analysis and processing. The CPU module is a computer processing module responsible for processing the electrical signal waveform and converting it into information on changes in external temperature and strain.

[0049] Please see Figure 3 , Figure 4 and Figure 5 The present invention also provides a method for manufacturing a printed fiber optic sensor with decoupled temperature strain as described above, the manufacturing method mainly comprising the following steps:

[0050] S1 array strips the coating layer 3 and cladding of the optical fiber to form multiple distributed receiving slots. Methods for locally array-removing the coating layer 3 and cladding of ordinary single-mode optical fiber include wire stripper removal, polishing, and chemical etching.

[0051] In this embodiment, a common single-mode optical fiber is taken, and the coating layer 3 of the single-mode optical fiber is stripped off at a local position along the optical fiber axis using optical fiber stripping pliers. The stripping dust is then blown away with a nitrogen gun. The part of the optical fiber with the coating layer 3 removed is placed in a low-concentration hydrofluoric acid (HF) solution, and the optical fiber is rotated at a uniform speed to remove the exposed optical fiber cladding.

[0052] S2 Fiber Fixing and Clamping. Both ends of the fiber are fixed to the feed motor 6 and take-up motor 11 respectively, and the ends are tightened to secure the fiber. The fiber in the processing area is fed and taken up by the feed motor 6 and take-up motor 11, facilitating long-distance fiber surface printing. The section of the fiber located between the feed motor 6 and take-up motor 11 is also respectively mounted on the left rotary motor 8 and right rotary motor 10.

[0053] S3 printing manufactures temperature-sensitive sensing structure 1 and thermal-sensitive sensing structure. The printhead 9 is installed on the printing equipment, and a high voltage is connected to the printhead 9. With the cooperation of the left rotary motor 8, right rotary motor 10, filament feed motor 6, and filament take-up motor 11, the temperature-sensitive sensing structure 1 and force-sensitive sensing structure 2 are fabricated at the locations where the coating layer 3 and cladding are removed in a distributed manner on the optical fiber.

[0054] The printing methods include, but are not limited to, 3D printing, inkjet printing, aerosol printing, and electrohydraulic inkjet printing. Different printing methods should be selected based on the type of sensitive material, viscosity, substrate characteristics, and printing environment.

[0055] In this embodiment, electrofluidic inkjet printing is selected as the printing method for the temperature strain sensing structure. Electrofluidic inkjet printing, as a high-resolution patterning method, can achieve on-demand fabrication of sub-micron level microstructures, making it a highly promising printing method for fabricating temperature strain sensing structures. For example... Figure 4As shown, temperature-sensitive ink is fed into an electrohydraulic printhead, which is then mounted on an electrohydraulic printing device. A high-voltage device connected to the printhead provides high voltage to the electrohydraulic printhead, creating an electric field that promotes the formation of a conical jet. The motion platform is controlled by a host computer, and with the cooperation of the left rotary motor 8, right rotary motor 10, wire feed motor 6, and wire take-up motor 11, the temperature-sensitive sensing structure 1 is fabricated by distributing the removal of the coating layer 3 and cladding layer on the optical fiber. After printing all the temperature-sensitive material to the predetermined positions, force-sensitive ink is replaced in the electrohydraulic printhead, and this step is repeated to print the force-sensitive ink to the predetermined positions, thus achieving the direct fabrication of the force-sensitive structure.

[0056] The sensor is packaged in S4, and then other components are installed to obtain the printed fiber optic sensor. The sensor packaging methods include, but are not limited to, printing the encapsulation layer, dip coating, and fiber optic coating. The printing encapsulation layer method uses the same apparatus as in S3 to print the coating layer 3.

[0057] In this embodiment, also on the electrohydraulic inkjet printing platform described in step S3, a polyimide (PI) precursor solution is supplied into the printhead, the high-voltage power supply is turned on, and the motion platform is controlled by the host computer. The polyimide precursor solution is sprayed onto the temperature-sensitive material and force-sensitive material areas printed in step S3 using the electrohydraulic inkjet printing printhead. With the cooperation of the left rotary motor 8 and the right rotary motor 10, the solution is sprayed evenly in the circumferential direction to achieve the encapsulation of the temperature-sensitive and force-sensitive sensing structures.

[0058] The present invention also provides an application of the decoupled temperature strain printed fiber optic sensor described above in aircraft skin signal acquisition, surgical robot radio frequency sensing, and engine performance monitoring.

[0059] Those skilled in the art will readily understand that the above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A printed fiber optic sensor capable of decoupling temperature strain, characterized in that: The printed fiber optic sensor includes an optical fiber, a temperature-sensitive sensing structure and a force-sensitive sensing structure distributed and embedded on the optical fiber; wherein, the material of the temperature-sensitive sensing structure is a temperature-sensitive fluorescent material, and the material of the force-sensitive sensing structure is a force-sensitive fluorescent material. The temperature-sensitive sensing structure and the force-sensitive sensing structure are used to detect information on external temperature and strain and emit corresponding fluorescence. The printed fiber optic sensor realizes in-situ detection of external temperature and strain and decoupling of temperature and strain based on the lifetime information and light intensity of the fluorescence. When a pump light source laser passes through the temperature-sensitive sensing structure and the force-sensitive sensing structure, the temperature-sensitive sensing structure and the force-sensitive sensing structure emit fluorescence of different wavelengths. The cladding and cladding layers of the optical fiber corresponding to the regions of the temperature-sensitive sensing structure and the force-sensitive sensing structure are removed, leaving only the fiber core. The optical fiber includes a fiber core, a cladding covering the outer periphery of the fiber core, and a coating covering the outer periphery of the cladding. The optical fiber has multiple distributed receiving slots, and a temperature-sensitive sensing structure and a force-sensitive sensing structure are prepared in the receiving slots by electrohydraulic inkjet printing. The receiving slots penetrate the coating and the cladding.

2. The printed fiber optic sensor capable of decoupling temperature strain as described in claim 1, characterized in that: The temperature-sensitive sensing structure and the force-sensitive sensing structure are arranged in a group, and the temperature-sensitive sensing structure and the force-sensitive sensing structure in the same group are respectively arranged in two adjacent receiving slots.

3. The printed fiber optic sensor capable of decoupling temperature strain as described in claim 1, characterized in that: The temperature-sensitive sensing structure and the force-sensitive sensing structure are arranged in a group, and the temperature-sensitive sensing structure and the force-sensitive sensing structure in the same group are arranged at intervals in the same receiving tank.

4. The printed fiber optic sensor capable of decoupling temperature strain as described in any one of claims 1-3, characterized in that: The printed fiber optic sensor further includes a pump source, a fiber coupler, a filter, a photodetector, a signal amplifier, and a processing module. The pump source emits laser light, which is transmitted to the fiber optic cable via the fiber coupler and then to the temperature-sensitive and force-sensitive sensing structures. The fluorescence generated by the temperature-sensitive and force-sensitive sensing structures propagates in the opposite direction and is transmitted to the filter via the fiber coupler. The filter filters the received fluorescence signal, extracts the fluorescence information to be analyzed, and transmits it to the photodetector. The photodetector converts the received fluorescence into an electrical signal and transmits it to the signal amplifier. The signal amplifier amplifies the received electrical signal and transmits it to the processing module. The processing module analyzes and processes the received electrical signal to achieve in-situ detection of external temperature and strain and decoupling of temperature and strain.

5. The printed fiber optic sensor capable of decoupling temperature strain as described in claim 4, characterized in that: Fluorescence lifetime is only related to temperature. Changes in fluorescence lifetime can be determined by monitoring the fluorescence decay rate (i.e., changes in fluorescence lifetime) using a photodetector. The processing module calculates the corresponding external temperature using the correlation between fluorescence lifetime and temperature. The correlation between fluorescence lifetime and temperature is as follows: ,in It is a constant. The ambient temperature.

6. A method for inkjet printing manufacturing of a decoupled temperature strain printed fiber optic sensor according to any one of claims 1-5, characterized in that, The method includes the following steps: (1) Multiple distributed receiving slots are fabricated on the optical fiber; (2) Using temperature-sensitive material and force-sensitive material as raw materials, respectively, the temperature-sensitive sensing structure and the force-sensitive sensing structure are prepared in the receiving tank by electrohydrodynamic inkjet printing, thereby obtaining the printed fiber optic sensor.

7. The application of a printed fiber optic sensor with decoupled temperature strain as described in any one of claims 1-5 in aircraft skin signal acquisition, surgical robot radio frequency sensing, and engine performance monitoring.

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