A packaging structure of a microstructure optical fiber pressure sensor

Abstract

The utility model discloses a microstructure formula optical fiber pressure sensor's packaging structure that measurement accuracy is high, reliability is high, including optical fiber, and the end of optical fiber forms FP cavity, and the FP cavity is provided with pressure sensitive diaphragm at the chamber mouth, and the outer periphery of optical fiber end is provided with the packaging tube, and the pipe wall of packaging tube is provided with the micropore that is through the inside and outside of pipe wall. Set up the micropore on the packaging tube, and the micropore can make blood through capillary action and seep into the channel, and the residual air in the inside of packaging tube is discharged in time and effectively, and the pressure transmission is ensured without lag, and the pressure in blood directly acts on the surface of pressure sensitive diaphragm, and the deviation between the pressure value that sensor measures and the actual blood pressure value does not occur, and the accuracy and reliability of measurement result are improved.

Description

Technical Field

[0001] This utility model relates to the field of fiber optic sensor technology, specifically to a packaging structure for a microstructure fiber optic pressure sensor. Background Technology

[0002] As an emerging sensing technology, fiber optic pressure sensors have demonstrated enormous application potential in modern medical diagnostics due to their unique physical characteristics. Compared to traditional electronic sensors, Fabry-Perot fiber optic pressure sensors have attracted significant attention due to their simple structure, relatively low manufacturing cost, and high measurement accuracy. In clinical applications, doctors need to monitor key physiological parameters such as arterial pressure, venous pressure, and intracardiac pressure in real time. Traditional pressure monitoring methods are often invasive and have limited accuracy. Fiber optic pressure sensors can effectively solve this problem; their ultra-fine fiber optic structure can be directly implanted into blood vessels or heart chambers through catheters, enabling continuous, real-time, and high-precision monitoring of blood pressure.

[0003] Currently, Fabry-Perot fiber optic pressure sensors still face challenges in clinical applications due to inadequate encapsulation protection technology. Existing encapsulation technologies primarily use polyimide (PI) material for simple protection of the Fabry-Perot cavity. While this provides basic mechanical protection, it reveals significant technical shortcomings in practical clinical applications, namely air trapping. When the fiber optic pressure sensor is implanted into the cardiovascular system, due to the high viscosity and surface tension of blood, coupled with resistance during blood flow, air inside the PI sleeve often cannot be effectively expelled in a timely manner, forming an air bubble layer between the blood and the pressure-sensitive diaphragm. The presence of this air bubble layer severely affects the normal transmission of pressure, preventing the pressure in the blood from directly acting on the surface of the pressure-sensitive diaphragm. This leads to a significant deviation between the pressure value measured by the sensor and the actual blood pressure value, severely impacting the accuracy and reliability of the measurement results. This not only limits the application range of Fabry-Perot fiber optic pressure sensors in high-pressure measurement scenarios but also poses a major obstacle to the widespread application of the sensor in the diagnosis of cardiovascular diseases. Utility Model Content

[0004] The purpose of this invention is to provide a packaging structure for a microstructure fiber optic pressure sensor that offers high measurement accuracy and reliability.

[0005] To achieve the above objectives, the technical solution adopted by this utility model is as follows: a packaging structure for a microstructure fiber optic pressure sensor, including an optical fiber, an FP cavity formed at the end of the optical fiber, a pressure-sensitive diaphragm disposed at the cavity opening of the FP cavity, a packaging tube disposed on the outer periphery of the end of the optical fiber, and micropores penetrating the inside and outside of the tube wall disposed on the tube wall of the packaging tube.

[0006] Furthermore, the proximal end of the encapsulation tube extends to the proximal side of the FP cavity, and the distal end protrudes to the distal side of the pressure-sensitive diaphragm to form an extended tube segment, wherein the micropores are disposed on the tube wall of the extended tube segment.

[0007] Furthermore, the micropores are irregularly arranged in both the circumferential and axial directions of the extended tube section.

[0008] Furthermore, the cross-section of the micropore is circular, the diameter of the circular pore is 15μm to 80μm, and the center distance between adjacent circular pores is 40μm to 120μm.

[0009] Furthermore, the cross-section of the micropores is elliptical, with the major axis of the elliptical pores being 40μm to 120μm, the minor axis being 20μm to 60μm, and the array spacing being 50μm to 150μm.

[0010] Furthermore, the cross-section of the micropore is triangular, with the base length of the triangular pore being 20μm to 100μm, the height being 15μm to 80μm, and the spacing between adjacent triangular pores being 30μm to 150μm.

[0011] Furthermore, the cross-section of the micropore is polygonal, and the diameter of the circumscribed circle of the polygonal pore is 30μm to 100μm.

[0012] Furthermore, the inner wall edge of the micropore has a streamlined or rounded transition, and the roughness Ra of the inner wall of the micropore is ≤0.5μm.

[0013] Furthermore, the inner surface of the micropores is treated with hydrophilicity, resulting in a static contact angle of less than 70° and a dynamic contact angle hysteresis of less than 15°.

[0014] Furthermore, the encapsulation tube is made of polyimide material with a wall thickness of 0.08mm to 0.25mm and an inner diameter of 0.6mm to 2.5mm.

[0015] In the above scheme, micropores are set on the encapsulation tube. The micropores allow blood to seep into the pores through capillary action, timely and effectively expelling residual air inside the encapsulation tube, ensuring that pressure transmission is lag-free. The pressure in the blood acts directly on the surface of the pressure-sensitive diaphragm, resulting in no deviation between the pressure value measured by the sensor and the actual blood pressure value, thus improving the accuracy and reliability of the measurement results. Attached Figure Description

[0016] Figure 1 A schematic diagram of the fiber optic pressure sensor packaging structure;

[0017] Figure 2 for Figure 1 A sectional view;

[0018] Figure 3This is a comparison chart of performance test curves for fiber optic pressure sensors using traditional packaging structures and those using the packaging structure of this invention. Detailed Implementation

[0019] To facilitate understanding, we first define the orientation: "proximal" or "proximal" refers to the side closer to the operator / doctor, while "distal" or "distal" refers to the side farther from the operator / doctor. See the attached diagram for further details. Figures 1-3 This utility model will be discussed in further detail.

[0020] A microstructured fiber optic pressure sensor packaging structure includes an optical fiber 10, with an FP cavity A formed at the end of the optical fiber 10. A pressure-sensitive diaphragm 20 is disposed at the opening of the FP cavity A. A packaging tube 30 is disposed on the outer periphery of the end of the optical fiber 10, and micropores 31 penetrating the inner and outer walls of the packaging tube 30 are disposed on the tube wall. The packaging tube 30 uses UV-curable epoxy adhesive to form a flexible adhesive layer between the inner side of the tube and the optical fiber 10 to avoid thermal stress. The micropores 31 allow blood to seep into the channels through capillary action, expelling residual air inside the packaging tube 30 and ensuring pressure transmission without hysteresis.

[0021] As a preferred embodiment of this utility model, the proximal end of the encapsulation tube 30 extends to the proximal side of the FP cavity A, ensuring the reliability of the connection between the encapsulation tube 30 and the optical fiber 10, and the meaningful part of the tube segment does not need to be provided with micropores 31; the distal end of the encapsulation tube 30 protrudes to the distal side of the pressure-sensitive diaphragm 20 and forms an extension tube segment 30a, and the micropores 31 are provided on the tube wall of the extension tube segment 30a, so as to timely and effectively discharge the air inside the encapsulation tube 30. The pressure in the blood acts directly on the surface of the pressure-sensitive diaphragm, so that there is no deviation between the pressure value measured by the sensor and the actual blood pressure value, thereby improving the accuracy and reliability of the measurement results.

[0022] Furthermore, multiple micropores 31 are irregularly arranged circumferentially and axially in the extension tube section 30a. The core principle of the protective function of the micropores 31 is "mechanical buffering + pressure equalization," rather than simple physical isolation. The specific mechanisms include: 1. Stress dispersion: The micropore structure forms a local flexible region. When external pressure fluctuates, the material around the pores elastically deforms to absorb the impact energy (similar to the principle of a honeycomb structure), preventing damage to the end face of the optical fiber 10 due to mechanical impact. 2. Dynamic pressure balance: The micropores allow blood to quickly penetrate, eliminating the pressure transmission delay caused by air gaps in traditional encapsulation (response time can be shortened to the millisecond level). The reasons for the irregular distribution of micropores 31 are as follows: 1. A regular array distribution may produce a light diffraction effect, affecting the optical performance and pressure measurement accuracy of the FP cavity A; 2. An irregular distribution can break the regular flow field, which is conducive to the rapid discharge of air bubbles. Example

[0023] The cross-section of the micropore 31 is circular, the diameter of the circular pore is 15μm to 80μm, and the center distance between adjacent circular pores is 40μm to 120μm. Example

[0024] The cross-section of the micropore 31 is elliptical, with the major axis of the elliptical pore being 40μm to 120μm, the minor axis being 20μm to 60μm, and the array spacing being 50μm to 150μm. Example

[0025] The cross-section of the micropore 31 is triangular, with the base length of the triangular pore being 20μm to 100μm, the height being 15μm to 80μm, and the spacing between adjacent triangular pores being 30μm to 150μm. Example

[0026] The cross-section of the micropore 31 is polygonal, and the diameter of the circumscribed circle of the polygonal pore is 30μm to 100μm.

[0027] Following the principles of fluid dynamics, the inner wall edge of the micropore 31 is streamlined or rounded to reduce fluid resistance and promote bubble discharge. The inner wall roughness Ra of the micropore 31 is ≤0.5μm.

[0028] Furthermore, the inner surface of the micropore 31 is treated with hydrophilicity, with a static contact angle of less than 70° and a dynamic contact angle hysteresis of less than 15°, to promote blood wetting and bubble desorption.

[0029] The encapsulation tube 30 is made of polyimide, which combines biocompatibility (ISO 10993 certified), high temperature resistance (potential for heat sterilization during surgery), and low elastic modulus (~3 GPa, suitable for microporous processing). Surface modification improves wear resistance and reduces blood protein adsorption. The wall thickness is 0.08mm to 0.25mm, and the inner diameter is 0.6mm to 2.5mm.

[0030] Figure 3 This is a comparison of performance test curves for fiber optic pressure sensors using traditional and novel packaging structures. As can be seen from the figure, compared to the traditional packaging structure (orange curve), the sensor with the triangular micro-hole structure (blue curve) shows an improvement in linearity (R²=0.99409 to R²=0.99995) and pressure response sensitivity (1.79 to 2.6). The directional venting design of the micro-holes effectively eliminates air bubble retention within the packaging tube, ensuring accurate pressure signal transmission and significantly improving the sensor's measurement accuracy and reliability.

[0031] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this utility model, and not to limit it. Although the utility model has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of this utility model, and they should all be covered within the scope of the claims and specification of this utility model.

Claims

1. A packaging structure of a microstructure optical fiber pressure sensor, comprising an optical fiber (10), an end of the optical fiber (10) is formed with an FP cavity (A), a pressure-sensitive diaphragm (20) is arranged at a cavity opening of the FP cavity (A), and an outer periphery of the end of the optical fiber (10) is provided with a packaging tube (30), characterized in that: The encapsulation tube (30) has micropores (31) that penetrate the inside and outside of the tube wall. ​ 2. The packaging structure of the microstructured optical fiber pressure sensor according to claim 1, characterized in that: The proximal end of the encapsulation tube (30) extends to the proximal side of the FP cavity (A) and the distal end protrudes to the distal side of the pressure-sensitive diaphragm (20) to form an extension tube segment (30a). The micropores (31) are disposed on the tube wall of the extension tube segment (30a).

3. The packaging structure of a micro-structured fiber pressure sensor according to claim 2, wherein: The micropores (31) are arranged irregularly in the circumferential and axial directions of the extension tube section (30a).

4. The packaging structure of the microstructured optical fiber pressure sensor according to claim 1 or 3, characterized in that: The cross-section of the micropore (31) is circular, the diameter of the circular pore is 15μm to 80μm, and the center distance between adjacent circular pores is 40μm to 120μm.

5. The packaging structure of a micro-structured fiber pressure sensor according to claim 1 or 3, characterized in that: The cross-section of the micropore (31) is elliptical, with the major axis of the elliptical pore being 40μm to 120μm, the minor axis being 20μm to 60μm, and the array spacing being 50μm to 150μm.

6. The packaging structure of a micro-structured fiber pressure sensor according to claim 1 or 3, characterized in that: The cross-section of the micropore (31) is triangular, the base length of the triangular pore is 20μm~100μm, the height is 15μm~80μm, and the distance between adjacent triangular pores is 30μm~150μm.

7. The packaging structure of a micro-structured fiber pressure sensor according to claim 1 or 3, characterized in that: The cross-section of the micropore (31) is polygonal, and the diameter of the circumscribed circle of the polygonal pore is 30μm to 100μm.

8. The packaging structure of a microstructure fiber optic pressure sensor according to claim 1, characterized in that: The inner wall edge of the micropore (31) is streamlined or rounded, and the roughness Ra of the inner wall of the micropore (31) is ≤0.5μm.

9. The packaging structure of a microstructure fiber optic pressure sensor according to claim 1, characterized in that: The inner surface of the micropore (31) is hydrophilic, with a static contact angle of less than 70° and a dynamic contact angle hysteresis of less than 15°.

10. The packaging structure of a microstructure fiber optic pressure sensor according to claim 1, characterized in that: The encapsulation tube (30) is made of polyimide material with a wall thickness of 0.08 mm to 0.25 mm and an inner diameter of 0.6 mm to 2.5 mm.

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