Pressure sensor and interventional pressure guidewire

Abstract

The application relates to the technical field of medical devices, in particular to a pressure sensor and an interventional pressure guide wire, wherein the pressure sensor comprises a pressure sensing unit and a temperature sensing unit connected to the rear end of the pressure sensing unit; the pressure sensing unit comprises a pressure interference cavity and a pressure diaphragm arranged at the front end of the pressure interference cavity; the temperature sensing unit comprises a temperature interference cavity and a reflecting film arranged at the front end of the temperature interference cavity; the reflecting film is arranged adjacent to the pressure interference cavity; the material of the reflecting film is IP-S photoresist. Based on the optical sensing technology, the application adopts the interference principle to realize the detection feedback of pressure and temperature changes, eliminates the influence of body temperature fluctuation or environmental temperature change on the pressure measurement result through temperature compensation, greatly improves the precision of the intravascular pressure measurement, and has the characteristics of high sensitivity, no electromagnetic interference and double-parameter measurement of pressure and temperature.

Description

Technical Field

[0001] This invention relates to the field of medical device technology, and in particular to a pressure sensor and an interventional pressure guidewire. Background Technology

[0002] Minimally invasive interventional surgery, as one of the important means of medical treatment for various cardiovascular and cerebrovascular diseases, is widely used for diseases such as vascular stenosis, aneurysms, atherosclerosis, and various types of thrombosis. In minimally invasive interventional surgery, various types of interventional surgical tools (such as catheters, guidewires, and vascular stents) are used by doctors to enter the blood vessel through the femoral or radial artery and reach the lesion site for diagnosis and treatment. Compared with traditional open surgery, endovascular minimally invasive interventional surgery has many unique advantages, such as shorter recovery time, lower risk of infection, less intraoperative blood loss, and less postoperative pain. Among these, the interventional pressure guidewire, as an important member of the interventional surgical tools, has wide application value and is often used to measure intravascular pressure during surgery. In neuro- and cardiovascular interventional surgeries, surgeons need to monitor changes in intravascular pressure in real time to make correct diagnostic and treatment decisions, which can greatly increase the success rate and treatment effect. During treatment, by inserting a pressure guidewire into the blood vessel at the surgical site, the surgeon can monitor changes in intravascular pressure in real time.

[0003] Interventional surgical instruments typically monitor changes in intravascular pressure using pressure sensors. Due to the limitations of human blood vessel size, catheter diameters are generally 1-2.64 mm, while guidewire diameters are even smaller, typically less than 0.038 inches (0.97 mm). Interventional guidewire devices used in coronary artery interventional therapy are often 0.014 inches (355 μm) in size. This strict requirement for small size limits the integration of many microelectromechanical systems (MEMS) sensors onto guidewires and catheters, significantly increasing the integration difficulty. Furthermore, in addition to computed tomography (CT) scans, many hospitals use magnetic resonance imaging (MRI) during interventional procedures. This necessitates that various sensors on guidewires and catheters possess electromagnetic interference (EMI) immunity, but MEMS sensors have poor electromagnetic compatibility and weak EMI immunity. Summary of the Invention

[0004] To address the problem of weak electromagnetic interference resistance in existing sensors, this invention provides a pressure sensor based on optical sensing technology. This sensor utilizes the principle of interference to detect and respond to changes in pressure and temperature, exhibiting high sensitivity, electromagnetic insufficiency, and the ability to measure both pressure and temperature parameters. This solves the problem of weak electromagnetic interference resistance in existing sensors.

[0005] The technical solution adopted by this invention to solve its technical problem is: A pressure sensor includes a pressure sensing unit, a temperature sensing unit connected to the rear end of the pressure sensing unit, and an optical fiber mounted to the rear end of the temperature sensing unit; wherein, The pressure sensing unit includes a pressure interference cavity and a pressure diaphragm disposed at the front end of the pressure interference cavity; The temperature sensing unit includes a temperature interference cavity and a reflective film disposed at the front end of the temperature interference cavity; The reflective film is disposed adjacent to the pressure interference cavity; The reflective film is made of IP-S photoresist.

[0006] Optionally, the pressure interference cavity is a Fabry-Perot interference cavity.

[0007] Optionally, the pressure diaphragm has a boss-type structure.

[0008] Optionally, the pressure film includes a planar film, a connecting post, a bottom reflective film, and a gold film connected sequentially from front to back.

[0009] Optionally, the diameter of the planar thin film is 240 μm, the diameter of the connecting post is 4 μm, and the diameter of the bottom reflective film is 50 μm.

[0010] Optionally, the thickness of the planar thin film is 3 μm, the thickness of the connecting post is 3 μm, and the thickness of the bottom reflective film is 3 μm.

[0011] Optionally, the cavity length of the pressure interference cavity is 105 μm.

[0012] Optionally, the cavity length of the temperature interference cavity is 180 μm.

[0013] Optionally, the pressure sensor is fabricated using two-photon micro / nano printing.

[0014] Another object of the present invention is to provide an interventional pressure guidewire, including the pressure sensor described above.

[0015] The beneficial effects of this invention are: The pressure sensor provided by this invention features a compact overall structure and small lateral dimensions, achieved by connecting a pressure sensing unit and a temperature sensing unit in series. This eliminates the need for additional lateral space and meets the small size requirements of interventional medical scenarios. Furthermore, based on optical sensing technology, the pressure sensor employs the principle of interference to detect and respond to changes in pressure and temperature. Temperature compensation eliminates the influence of body temperature fluctuations or changes in ambient temperature on the pressure measurement results, significantly improving the accuracy of intravascular pressure measurement. It also features high sensitivity, electromagnetic insufficiency, and dual-parameter measurement of pressure and temperature. Attached Figure Description

[0016] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0017] Figure 1 The pressure sensor in this invention has a simple structure. Figure 1 ; Figure 2 yes Figure 1 Sectional view along line AA; Figure 3 The pressure sensor in this invention has a simple structure. Figure 2 ; Figure 4 The pressure sensor in this invention has a simple structure. Figure 3 ; Figure 5 This is a simplified structural diagram of the pressure diaphragm in this invention; Figure 6 This is a schematic diagram of the deformation of the pressure film in this invention; Figure 7 This is a schematic diagram of the decoupling of pressure and temperature as two parameters in this invention; Figure 8 This is a spectral data diagram from the present invention.

[0018] In the figure: 1-Pressure sensing unit; 11-Pressure interference cavity; 12-Pressure film; 121-Planar film; 122-Connecting post; 123-Bottom reflective film; 124-Gold film; 13-Pressure sensing body; 131-Interference cavity sidewall; 132-Temperature sensing positioning stage; 133-Temperature sensing assembly sidewall; 1331-Photocurable adhesive adsorption ramp; 2-Temperature sensing unit; 21-Temperature interference cavity; 22-Reflective film; 23-Temperature sensing body; 231-Assembly ramp; 232-Fiber optic fixing sidewall; 233-Fiber optic assembly cavity; 234-Fiber optic fixing plane; 3-Fiber optic cable. Detailed Implementation

[0019] The present invention will now be described in further detail. The embodiments described below are exemplary and intended to explain the present invention, and should not be construed as limiting the present invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort are within the scope of protection of the present invention.

[0020] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

[0021] To address the problem of weak electromagnetic interference resistance in existing sensors, this invention provides a pressure sensor, see [link to relevant documentation]. Figures 1-4As shown, the device includes a pressure sensing unit 1, a temperature sensing unit 2 connected to the rear end of the pressure sensing unit 1, and an optical fiber 3 mounted on the rear end of the temperature sensing unit 2. It should be noted that in this invention, the rear end refers to the end of the pressure sensor closest to the optical fiber, and the front end refers to the end furthest from the optical fiber. Preferably, the pressure sensing unit 1 and the temperature sensing unit 2 are designed as a single, compact structure. The pressure sensing unit 1 measures pressure information and includes a pressure interference cavity 11 and a pressure diaphragm 12 disposed at the front end of the pressure interference cavity 11. When the pressure changes, the pressure diaphragm 12 deforms, causing a change in the cavity length of the pressure interference cavity 11. The pressure can be measured by the relationship between the change in cavity length and the change in pressure. The temperature sensing unit 2 measures temperature information and includes a temperature interference cavity. 21, and a reflective film 22 disposed at the front end of the temperature interference cavity 21; wherein the temperature interference cavity 21 is an IP-S interference cavity, which is a solid structure. The cavity is a semi-transparent, light-transmitting solid cylinder, so that part of the incident light is reflected and part of the incident light penetrates the temperature interference cavity 21 and enters the pressure interference cavity 11; specifically, the temperature interference cavity 21 is preferably made of IP-S photoresist. The temperature interference cavity 21 functions as a temperature sensor for temperature compensation. The reflective film 22 serves as the second reflective surface of the temperature interference cavity 21 (IP-S cavity) and reflects part of the reflected light; the reflective film 22 is disposed adjacent to the pressure interference cavity 11; the reflective film 22 is made of IP-S photoresist; specifically, the temperature sensing unit 2 measures the temperature based on the micro-deformation caused by the thermal expansion of the material, which causes the cavity length of the temperature interference cavity 21 to increase when heated and to decrease when cooled.

[0022] Currently, the primary application of pressure guidewires is measuring the fractional flow reserve (FFR) of the coronary arteries to assess the degree of vascular occlusion. As a functional evaluation indicator, FFR plays a crucial guiding role in cardiovascular disease treatment strategies. Previous studies have confirmed that FFR-guided interventional treatment strategies are not only safe and economical but also improve patient outcomes. Through long-term basic and clinical research, FFR has become a recognized indicator for the functional evaluation of coronary artery stenosis. Lesions with an FFR < 0.75 are recommended for revascularization, while lesions with an FFR > 0.80 are recommended for drug therapy. The FFR range of 0.75–0.80 is considered a gray area; surgeons can determine whether to perform revascularization based on the patient's clinical condition and the importance of vascular blood supply. FFR is mainly obtained by calculating the ratio of pressure distal to the stenosis to pressure at the aortic root. The pressure distal to the stenosis can be measured using a pressure guidewire at maximum perfusion flow (through intracoronary or intravenous injection of papaverine or adenosine).

[0023] Pressure guidewire numerical drift refers to unexpected deviations or changes in the measured hemodynamic parameters during the use of the pressure guidewire. This drift can affect the physician's assessment of the patient's coronary artery function, thereby influencing clinical decisions. Pressure guidewire sensors are typically very sensitive to temperature, and temperature fluctuations can cause numerical drift. Therefore, changes in the operating room temperature environment or the temperature transition of the guidewire inside and outside the body can affect the measurement results. Based on this, to provide accurate and stable pressure measurement results during clinical use, reduce potential errors in the measurement results, and avoid affecting the physician's assessment and treatment of the patient's condition, this invention introduces a temperature sensing unit 2 connected in series with the pressure sensing unit 1 to achieve temperature compensation, thereby improving the accuracy of pressure measurement.

[0024] The pressure sensor provided by this invention, by connecting the pressure sensing unit 1 and the temperature sensing unit 2 in series, has a compact overall structure and small lateral size, requiring no additional lateral space and meeting the small size requirements of interventional medical scenarios. Furthermore, this pressure sensor is based on optical sensing technology and uses the interference principle to detect and respond to changes in pressure and temperature. Temperature compensation eliminates the influence of body temperature fluctuations or changes in ambient temperature on the pressure measurement results, significantly improving the accuracy of intravascular pressure measurement. It features high sensitivity, electromagnetic insufficiency, and dual-parameter measurement of pressure and temperature.

[0025] Furthermore, the present invention preferably uses a Fabry-Perot interferometer cavity 11 as the pressure interference cavity. The Fabry-Perot interferometer cavity is a structure that achieves sensing based on the principle of multi-beam interference, and has advantages such as high sensitivity, high contrast of interference signals, and simple demodulation. Specifically, the cavity length change of the Fabry-Perot interferometer cavity is linearly related to the pressure change. When external pressure acts on the pressure film 12 and causes deformation, the cavity length changes. By demodulating the offset of the interference spectrum, the external pressure value can be accurately calculated, resulting in high measurement accuracy, simple signal processing, and the ability to meet the requirements of real-time measurement.

[0026] See Figure 5 As shown, in order to improve the sensitivity of the pressure sensor, the pressure film 12 is preferably of a boss-shaped structure. The advantage of the boss-shaped film is that the reflective surface of the pressure film 12 is always flat, which helps to improve the overall stability of the sensor.

[0027] Specifically, the preferred pressure film 12 of this invention comprises a planar film 121, a connecting post 122, a bottom reflective film 123, and a gold film 124 connected sequentially from front to back. By adopting a layered, boss-type pressure film 12, each layer performs a different function, resulting in superior overall performance. The planar film 121 is located at the front end, directly contacting the measured fluid medium and deforming under external pressure, thus converting pressure into deformation. The connecting post 122 connects the planar film 121 and the bottom reflective film 123, transferring the deformation of the planar film 121 to the bottom reflective film 123 while reducing stress concentration at the connection point and improving structural stability. The bottom reflective film 123 serves as the rear reflective surface of the pressure interference cavity, forming a Fabry-Perot interference cavity together with the front end structure. The gold film 124, deposited at the rear end of the bottom reflective film 123, improves reflectivity, enhances the intensity of the interference signal, increases the contrast of the interference signal, reduces demodulation difficulty, and improves measurement accuracy.

[0028] The present invention preferably has a planar thin film 121 with a diameter of 240 μm, a connecting post 122 with a diameter of 4 μm, and a bottom reflective thin film 123 with a diameter of 50 μm. By optimizing the dimensions of each part of the protruding pressure film, optimal parameters that balance sensitivity, structural strength, and overall size are obtained. Specifically, the planar thin film 121 with a diameter of 240 μm ensures sufficient force-bearing area to generate sufficient deformation while controlling the overall lateral size of the sensor, meeting the small size requirements of the intervention scenario. The connecting post 122 with a diameter of 4 μm significantly reduces the constraint of the connecting post 122 on the deformation of the planar thin film 121, allowing the planar thin film 121 to deform more easily under pressure, thereby improving the pressure sensitivity of the sensor. The bottom reflective thin film 123 with a diameter of 50 μm satisfies the area requirement as a reflective surface, ensuring sufficient reflected light intensity, while avoiding excessive size that would lead to a bulky overall structure, thus controlling the overall size of the sensor. This size matching has been experimentally verified to achieve an optimal balance between sensitivity and stability.

[0029] In this invention, the thickness of the planar thin film 121 is preferably 3 μm, the thickness of the connecting post 122 is 3 μm, and the thickness of the bottom reflective film 123 is 3 μm. By optimizing the thickness of each layer, the sensitivity and mechanical strength of the pressure film 12 are further balanced. The planar thin film 121 has a thickness of 3 μm, which provides sufficient elasticity to produce significant deformation under pressure, ensuring sensor sensitivity, and sufficient mechanical strength to prevent rupture or plastic deformation due to excessive pressure, thus improving the reliability and service life of the sensor. The connecting post 122 and the bottom reflective film 123 are both 3 μm thick, which ensures structural stability without increasing the overall axial length of the sensor, controlling the overall size of the sensor and meeting the requirements of the intervention scenario.

[0030] The present invention preferably has a cavity length of 105 μm for the pressure interference cavity 11. This cavity length can match the wavelength range of commonly used demodulation light sources, ensuring good contrast of the interference spectrum, avoiding excessively high interference order caused by excessive cavity length, reducing demodulation difficulty, and ensuring sufficient sensitivity in small-sized sensors with a cavity length of 105 μm, without causing insufficient sensitivity due to excessively short cavity length.

[0031] The preferred cavity length of the temperature interference cavity 21 in this invention is 180 μm. On the one hand, since temperature sensitivity mainly comes from the thermal expansion effect of the material, the longer the cavity length, the greater the change in cavity length under the same temperature change, and the higher the temperature measurement sensitivity. A cavity length of 180 μm can provide sufficiently high temperature sensitivity to meet the temperature compensation requirements for temperature measurement accuracy. On the other hand, a cavity length of 180 μm controls the overall axial length of the sensor, preventing the overall size of the sensor from becoming too large due to excessive cavity length, which would affect its integration in the interventional guidewire. At the same time, this cavity length can also ensure that the interference signal of the temperature interference cavity has good contrast, which is convenient for demodulation and ensures the temperature measurement accuracy.

[0032] The present invention preferably uses two-photon micro-nano printing to fabricate the pressure sensor. Compared with traditional MEMS fabrication processes, two-photon micro-nano printing can print a complete sensor structure in just one step, without the need for complex photolithography, etching, bonding and other multiple processes. The process is simple, the processing cycle is short, the cost is low, and the structural parameters can be flexibly adjusted according to the requirements, resulting in high development efficiency. At the same time, the structure fabricated by two-photon micro-nano printing has high precision and good dimensional consistency, which can ensure the measurement repeatability and accuracy of the sensor, making it very suitable for small-batch customization and large-scale production.

[0033] Specifically, as a preferred embodiment, the pressure sensing unit 1 of the present invention includes a pressure sensing body 13, which includes an interference cavity sidewall 131, a temperature sensing positioning stage 132, and a temperature sensing assembly sidewall 133 connected in sequence. The interference cavity sidewall 131 and the pressure film 12 enclose a pressure interference cavity 11. The temperature sensing positioning stage 132 is used to install and position the temperature sensing unit 2. The temperature sensing positioning stage 132 and the temperature sensing assembly sidewall 133 enclose an installation cavity for the temperature sensing unit 2. Preferably, the lower end of the temperature sensing assembly sidewall 133 is provided with a light-curing adhesive adsorption ramp 1331.

[0034] The temperature sensing unit 2 of the present invention preferably includes a temperature sensing body 23, which includes a connected assembly ramp 231 and an optical fiber fixing sidewall 232. The assembly ramp 231 is adapted to cooperate with the temperature sensing positioning platform 132 and the temperature sensing assembly sidewall 133 to realize the assembly of the pressure sensing unit 1 and the temperature sensing unit 2. The optical fiber fixing sidewall 232 encloses and forms an optical fiber assembly cavity 233, which is suitable for installing optical fibers. To facilitate the assembly of optical fibers, an optical fiber fixing plane 234 is provided at the front end of the optical fiber assembly cavity 233.

[0035] The temperature-compensated guidewire pressure sensor based on Fabry-Perot interferometer microcavity provided by this invention can be integrated with a 0.014-inch interventional guidewire and a medical hypotube of the same size.

[0036] The detection process of the pressure sensor provided by this invention is as follows: The sensor was first immersed in physiological saline for 24 hours as a stability pretreatment. The sensor reaches the designated working position, simultaneously measuring pressure and temperature, and collecting spectral signals in real time; The obtained spectral signal will be filtered and demodulated to obtain the spectral shifts of the two interferometric cavities (IP-S cavity and hybrid cavity); By substituting the spectral shifts of the two interference cavities into the temperature-compensated pressure analytical equation, the pressure change is obtained, thus completing the temperature-compensated pressure measurement.

[0037] Its sensing principle is as follows: A schematic diagram of the deformation of the pressure diaphragm 12 during the measurement process is shown below. Figure 6 As shown, the deformation of the pressure interference cavity is: Where h is the thickness of the planar thin film 121 (μm); d is the cavity length of the Fabry-Perot pressure interference cavity 11 (μm); Δd is the change in cavity length of the Fabry-Perot pressure interference cavity 11 (nm); μ is the Poisson's ratio of the thin film; P is the pressure on the pressure thin film 12, i.e., the measured pressure (mmHg); R is the effective radius of the Fabry-Perot pressure interference cavity 11 (μm); E is the elastic modulus of the planar thin film 121 (Pa); and h is the thickness of the planar thin film 121 (μm).

[0038] Deformation of temperature interference cavity 21: Where ΔL is the change in cavity length of the IP-S interferometer cavity, and L0 and L T These represent the initial cavity length and the cavity length after thermal expansion of the IP-S interference cavity, respectively. α is the linear thermal expansion coefficient of the interference cavity material, and ΔT is the temperature change.

[0039] The relationship between the change in cavity length of the two Fabry-Perot interferometer microcavities and the shift in the wavelength of the reflected wave is shown in the following equation: Where λm is the initial reflection center wavelength (nm); Δλm is the peak center wavelength offset (nm).

[0040] Construct analytical equations for pressure and temperature as two parameters: Where, Δλ IP-S and Δλ Hybrid These represent the wavelength shifts of the temperature interference cavity 21 and the mixing cavity, respectively. The mixing cavity is composed of the pressure interference cavity 11 and the temperature interference cavity 21. k IP For the pressure sensitivity of the temperature interference cavity 21, k IT For the temperature sensitivity of the temperature interference cavity 21, k HP k is the pressure sensitivity of the mixing chamber. HT This refers to the temperature sensitivity of the mixing chamber.

[0041] Due to structural design limitations, the temperature interference cavity 21 does not respond to pressure; therefore, its pressure sensitivity k is limited. IP The value is zero. Substituting it into the above formula, we get: By reorganizing the above formulas, we can obtain the relationship between the pressure and temperature changes and the wavelength shift of the two microcavities: By combining the formulas, we can obtain the accurate pressure change with temperature compensation: In summary, a pressure decoupling equation with temperature compensation function was established. The pressure and temperature changes are decoupled through a pressure and temperature interference cavity. A schematic diagram of the pressure and temperature two-parameter decoupling is shown below. Figure 7 As shown; spectral data plot as shown Figure 8 As shown, (a) is the original spectrum of the sensor; (b) is the optical path length of the FFT-analyzed dual-cavity cavity; (c) is the interference spectrum corresponding to the temperature interference cavity; and (d) is the interference spectrum corresponding to the hybrid cavity.

[0042] The pressure sensor in this invention can be prepared according to the following method: Preprocessing stage: (1) 3D modeling and model slicing: Based on the optical-mechanical-materials coupling characteristics of the sensor, a 3D model of the Fabry-Perot interferometer cavity (pressure interferometer cavity 11 and temperature interferometer cavity 21) was designed using SolidWorks software and exported as an STL file. Layer slicing was performed using DeScribe2.3 professional slicing software (Nanoscribe GmbH), and parameters such as scanning layer thickness and spacing were set to generate TPP laser path control code files.

[0043] (2) Substrate pretreatment and photoresist addition: Select an ITO conductive glass slide with a specification of 25×25×0.7mm as the printing substrate, fix the glass slide on the printer substrate template, use a special dropper to add a drop of IP-S photoresist to the center area of ​​the glass slide, then place the entire template on the worktable of the two-photon printer and fix it, and finally move it into the laser printing chamber.

[0044] Printing and processing stage: (3) Laser focusing calibration and substrate positioning: A 25× oil immersion objective (EC Plan-Neofluar, NA=1.4, Carl Zeiss) was used to focus a femtosecond laser into the photoresist. The axial position of the objective was manually adjusted by the confocal microscope real-time monitoring system software, combined with the laser reflection signal and CCD imaging, so that the laser focus point coincided with the substrate surface.

[0045] (4) Printing parameter control: Adjust the laser power through the power modulator to ensure that the polymerization threshold matches the scanning speed and avoid the coffee ring effect caused by overexposure. Control the external environment temperature at 18-25℃ and humidity <60% RH. After completing the printing parameter and laser parameter settings, load the generated job.gwl file into the printer control software and click the Start button to start printing.

[0046] Post-processing stage: (5) Structural Cleaning and Gold Plating: After printing, remove the glass slide with the sensor structure and place it in a dedicated cleaning rack. Immerse the glass slide in a container containing propylene glycol monomethyl ether acetate (PGMEA) solution for cleaning (40 min for air microcavity cleaning, 30 min for IP-S microcavity cleaning). Then, transfer the glass slide to a container containing isopropanol (IPA) solution for immersion cleaning (30 min for air microcavity cleaning, 20 min for IP-S microcavity cleaning) to completely remove uncured photoresist while retaining the sensor structure. Finally, remove the glass slide and place it in a fume hood to allow the cleaning solution to evaporate naturally. After drying, fix the glass slide in the vacuum gold plating machine with the bottom surface facing up to deposit a gold film on the lower reflective surface.

[0047] (6) Quality inspection: The surface structure of the microcavity was observed using an optical microscope to confirm that there were no structural defects. The initial cavity length of the FP cavity was measured using a spectrometer, and the alignment of the fiber optic rays was tested using red light from an optical power meter to verify that the manufacturing precision met the design requirements.

[0048] The integration and packaging steps of the sensing element are as follows: Step 1: Place the glass slide containing the sensing element into the positioning frame of the micromanipulation platform and adjust the slide to the appropriate position. Then fix the diced single-mode fiber onto the fiber holder and adjust the exposed bare fiber to the appropriate length.

[0049] Step 2: Adjust the positions of the microscope lens and the macro camera lens so that they are both focused on the plane where the sensor element is located, providing a dual-view field of view to assist in subsequent precise positioning.

[0050] Step 3: Adjust the knob of the multi-degree-of-freedom micromanipulation stage to move the optical fiber in space. Combine the dual observation perspectives of the macro camera and microscope to align the optical fiber with the mounting hole on the sensing element.

[0051] Step 4: Continue to carefully turn the knob of the multi-degree-of-freedom micromanipulation stage to slowly insert the optical fiber into the assembly hole, and observe the position of the optical fiber end face from two perspectives to ensure that the optical fiber end face is in close contact with the positioning stage inside the sensing element, thus ensuring the accuracy of the sensing interference cavity.

[0052] Step 5: Fix the dispensing fiber onto another multi-degree-of-freedom micromanipulation stage, and achieve precise displacement by turning the control knob. First, move the dispensing fiber to a position close to the upper end face of the transmission fiber, and slowly lower the height of the dispensing fiber until its ghost image appears in the microscope view, and at the same time, the dispensing fiber can be clearly observed in the macro camera view, indicating that the dispensing fiber has approached the designated target position. Continue to adjust the position of the dispensing fiber to the target position, and transfer a small amount of photoresist from the end of the dispensing fiber to the assembly hole gap through capillary action and van der Waals forces.

[0053] Step Six: After waiting for the photoresist to completely fill the gaps in the mounting holes, irradiate the liquid photoresist with a 405nm wavelength ultraviolet laser for two minutes to allow it to fully cure. Once the photoresist has completely fixed the sensing element and the optical fiber, rotate the knob of the multi-degree-of-freedom micromanipulation stage that holds the optical fiber to move the fiber backward, simultaneously detaching the sensing element from the glass slide, thus completing the integrated packaging of the sensing element and the optical fiber.

[0054] Another object of the present invention is to provide an interventional pressure guidewire, which includes the pressure sensor described above.

[0055] The interventional pressure guidewire provided by this invention employs a pressure sensor that connects pressure sensing unit 1 and temperature sensing unit 2 in series. This results in a compact overall structure with a small lateral dimension, eliminating the need for additional lateral space and meeting the small sensor size requirements of interventional medical scenarios. Furthermore, this pressure sensor is based on optical sensing technology and uses the interference principle to detect and respond to pressure and temperature changes. Temperature compensation eliminates the influence of body temperature fluctuations or ambient temperature changes on pressure measurement results, significantly improving the accuracy of intravascular pressure measurement. It features high sensitivity, electromagnetic insufficiency, and dual-parameter measurement of pressure and temperature.

[0056] Based on the above-described preferred embodiments of the present invention, and through the foregoing description, those skilled in the art can make various changes and modifications without departing from the inventive concept. The technical scope of this invention is not limited to the contents of the specification, but must be determined according to the scope of the claims.

Claims

1. A pressure sensor, characterized in that, It includes a pressure sensing unit (1), a temperature sensing unit (2) connected to the rear end of the pressure sensing unit (1), and an optical fiber (3) assembled to the rear end of the temperature sensing unit (2); wherein, The pressure sensing unit (1) includes a pressure interference cavity (11) and a pressure film (12) disposed at the front end of the pressure interference cavity (11). The temperature sensing unit (2) includes a temperature interference cavity (21) and a reflective film (22) disposed at the front end of the temperature interference cavity (21). The reflective film (22) is disposed adjacent to the pressure interference cavity (11); The reflective film (22) is made of IP-S photoresist.

2. The pressure sensor as described in claim 1, characterized in that, The pressure interference cavity (11) is a Fabry-Perot interference cavity.

3. The pressure sensor as described in claim 1, characterized in that, The pressure membrane (12) has a boss-type structure.

4. The pressure sensor as described in claim 3, characterized in that, The pressure film (12) includes a planar film (121), a connecting post (122), a bottom reflective film (123), and a gold film (124) connected in sequence from front to back.

5. The pressure sensor as described in claim 4, characterized in that, The diameter of the planar thin film (121) is 240 μm, the diameter of the connecting post (122) is 4 μm, and the diameter of the bottom reflective film (123) is 50 μm.

6. The pressure sensor as described in claim 4, characterized in that, The thickness of the planar thin film (121) is 3 μm, the thickness of the connecting post (122) is 3 μm, and the thickness of the bottom reflective film (123) is 3 μm.

7. The pressure sensor as described in claim 1, characterized in that, The cavity length of the pressure interference cavity (11) is 105 μm.

8. The pressure sensor as described in claim 1, characterized in that, The cavity length of the temperature interference cavity (21) is 180 μm.

9. The pressure sensor according to any one of claims 1-8, characterized in that, The pressure sensor was fabricated using two-photon micro-nano printing.

10. An interventional pressure guidewire, characterized in that, Including the pressure sensor as described in any one of claims 1-9.

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