Optical fiber probe and method for manufacturing an optical fiber probe

Abstract

The application provides an optical fiber probe and a manufacturing method thereof. The manufacturing method comprises the following steps: inserting an optical fiber into a tubular shell; inserting a glue injection head of a glue injection machine into the tubular shell from the end of the tubular shell and injecting optical glue; stopping the glue injection after the optical glue fills the space formed by the preset interval, and moving the inserted end to be in contact with the glue injection head; inserting a sapphire column into the end of the tubular shell; and performing low-temperature curing on the part of the tubular shell with the optical glue, so as to finally form the optical fiber probe. The optical fiber probe comprises an optical fiber, a tubular shell, optical glue and a sapphire column. The optical fiber and the sapphire column are both located in the tubular shell, and the sapphire column is located at the end of the tubular shell and in contact with the inserted end of the optical fiber. The optical fiber, the tubular shell and the sapphire column are fixed by the optical glue, and the optical fiber probe is not operated in a vacuum environment, so that the manufacturing cost of the optical fiber probe is reduced, and the manufacturing speed is faster and the efficiency is improved.

Description

Technical Field

[0001] This application belongs to the field of multiphase flow gas holdup measurement technology, specifically relating to an optical fiber probe and a method for manufacturing the optical fiber probe. Background Technology

[0002] Multiphase flow is a complex and ubiquitous flow pattern, widely applied in industries such as energy and chemicals. Oil-gas-water three-phase flow, as a form of multiphase flow, permeates the entire oil and gas extraction process. Gas holdup is a crucial aspect of oil-gas-water three-phase flow research and a necessary parameter for dynamic monitoring of oil and gas wells. Compared to conductivity, ultrasonic, and X-ray methods, fiber optic probes for gas holdup offer advantages such as small size, fast response, high sensitivity, and resistance to electromagnetic interference. In recent years, their application in the field of dynamic monitoring of oil and gas wells has attracted considerable attention from researchers both domestically and internationally.

[0003] The first challenge in using fiber optic probes for dynamic monitoring of oil and gas wells is ensuring their reliability under high-temperature and high-pressure downhole environments. Existing high-reliability fiber optic probes for gas holdup measurement are manufactured using gold-based solder brazing sealing technology, capable of withstanding temperatures up to 150°C and pressures up to 100 MPa.

[0004] However, in practical applications, fiber optic probes are easily damaged by impacts from sand and debris in the well, making them consumables. Furthermore, the brazing sealing process requires a vacuum environment, which complicates the probe manufacturing process and increases production costs. Summary of the Invention

[0005] This application provides a method for fabricating an optical fiber probe, addressing the problem that existing optical fiber probes employ a brazing sealing process that requires a vacuum environment, resulting in complex fabrication processes and high costs. The method includes:

[0006] The optical fiber is inserted into the tubular shell, with a preset distance between the inserted end of the optical fiber and the end of the tubular shell.

[0007] Insert the dispensing head of the dispensing machine into the end of the tubular housing and inject the optical conductive adhesive into the tubular housing from the end of the tubular housing;

[0008] After the optical conductive adhesive fills the space formed by the preset spacing, stop the dispensing and move the protruding end to contact the dispensing head;

[0009] Remove the injection head from the tubular housing and insert the sapphire pillar from the end of the tubular housing until the end face of the sapphire pillar contacts the inserted end.

[0010] The optical conductive adhesive is cured at low temperature to form an optical fiber probe.

[0011] In one feasible implementation, after inserting the optical fiber into the tubular housing, the following steps are included:

[0012] The exposed end of the optical fiber is detachably fixed to the first end of the tubular shell;

[0013] After stopping the glue injection, the process also includes: disassembling and separating the exposed end of the optical fiber from the beginning of the tubular shell.

[0014] In one feasible implementation, the preset spacing is 100mm-150mm.

[0015] In one feasible implementation, the sapphire pillar is inserted from the end of the tubular casing until the end face of the sapphire pillar contacts the inserted end, including:

[0016] Apply epoxy resin adhesive to the edge of the contact point between the sapphire pillar and the tubular outer shell.

[0017] After the optical conductive adhesive is cured at low temperature, the process also includes removing the epoxy resin adhesive at high temperature.

[0018] In one feasible implementation, the temperature for removing the epoxy resin adhesive is 145℃-155℃, and the removal time is 3min-7min.

[0019] In one feasible implementation, the optical conductive adhesive is cured at low temperature in an oven; then the temperature of the oven is increased to remove the epoxy resin adhesive.

[0020] In one feasible implementation, the optical conductive adhesive is cured at a temperature of 75℃-85℃ for a curing time of 25min-35min.

[0021] In one feasible implementation, before inserting the optical fiber into the tubular housing, the following steps are included:

[0022] After vacuum degassing or centrifugal degassing, the optical conductive adhesive is placed into the dispensing machine.

[0023] In one feasible implementation, before inserting the optical fiber into the tubular housing, the following steps are also included:

[0024] The optical fiber and sapphire pillar are pre-treated, including polishing both ends of the optical fiber and the sapphire pillar.

[0025] The optical fiber, sapphire pillar, and tubular shell are cleaned. The cleaning process includes ultrasonic cleaning of the tubular shell, polished optical fiber, and polished sapphire pillar. The cleaning agent for ultrasonic cleaning is acetone or alcohol.

[0026] Another embodiment of this application provides an optical fiber probe, which is manufactured using any of the above-described methods for fabricating optical fiber probes; the optical fiber probe includes an optical fiber, a tubular shell, optical conductive adhesive, and a sapphire pillar;

[0027] Both the optical fiber and the sapphire pillar are located inside the tubular shell, with the sapphire pillar located at the end of the tubular shell and in contact with the insertion end of the optical fiber.

[0028] Optical conductive adhesive is filled between the portion of the optical fiber near the sapphire pillar and the tubular outer shell, and the length of the optical conductive adhesive along the extension direction of the optical fiber is equal to or less than the preset spacing.

[0029] This application provides a method for fabricating an optical fiber probe, comprising: inserting an optical fiber into a tubular shell, with a preset gap between the inserted end of the optical fiber and the end of the tubular shell; inserting the dispensing head of a dispensing machine from the end of the tubular shell and injecting optical conductive adhesive into the tubular shell from the end of the tubular shell; stopping the dispensing after the optical conductive adhesive fills the space formed by the preset gap, and moving the inserted end to contact the dispensing head; removing the dispensing head from the tubular shell, inserting a sapphire pillar from the end of the tubular shell until the end face of the sapphire pillar contacts the inserted end; and subjecting the portion of the tubular shell containing the optical conductive adhesive to low-temperature curing to finally form the optical fiber probe. This application also provides an optical fiber probe, comprising an optical fiber, a tubular shell, optical conductive adhesive, and a sapphire pillar; both the optical fiber and the sapphire pillar are located inside the tubular shell, with the sapphire pillar located at the end of the tubular shell and in contact with the inserted end of the optical fiber; the optical conductive adhesive fills the space between the portion of the optical fiber near the sapphire pillar and the tubular shell, and the length of the optical conductive adhesive along the direction of optical fiber extension is equal to or less than the preset gap. This application uses optical conductive adhesive to fix the optical fiber, tubular shell and sapphire pillar, eliminating the need for operation in a vacuum environment, thus reducing the manufacturing cost of the optical fiber probe. Furthermore, this method is faster and more efficient. Attached Figure Description

[0030] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the implementation of the invention and, together with the description, serve to explain the principles of the embodiments of the invention. It is obvious that the drawings described below are merely some embodiments of the invention, and those skilled in the art can obtain other drawings based on these drawings without any inventive effort.

[0031] Figure 1 A flowchart illustrating a method for fabricating an optical fiber probe, as shown in an exemplary embodiment of this application;

[0032] Figure 2 This is a schematic diagram illustrating the operation of inserting an optical fiber into a tubular housing, as shown in an exemplary embodiment of this application.

[0033] Figure 3 This is a schematic diagram illustrating the operation of injecting optical conductive adhesive into a tubular housing, as shown in an exemplary embodiment of this application.

[0034] Figure 4This is a schematic diagram illustrating the operation of inserting a sapphire pillar into a tubular housing, as shown in an exemplary embodiment of this application.

[0035] Figure 5 A schematic diagram illustrating the low-temperature curing operation of the optical conductive adhesive, as shown in an exemplary embodiment of this application:

[0036] Figure 6 A flowchart illustrating a method for fabricating an optical fiber probe, as shown in another exemplary embodiment of this application;

[0037] Figure 7 A flowchart illustrating a method for fabricating an optical fiber probe, which is another exemplary embodiment of this application;

[0038] Figure 8 A flowchart illustrating a method for fabricating an optical fiber probe, which is yet another exemplary embodiment of this application;

[0039] Figure 9 This is a schematic diagram of the structure of an optical fiber probe shown in an exemplary embodiment of this application.

[0040] Explanation of reference numerals in the attached figures:

[0041] 1-Tubular outer shell; 2-Fiber optic cable; 3-Dispensing head; 4-Dispensing machine; 5-Sapphire pillar; 6-Oven;

[0042] 11-The first end of the tubular shell; 12-The last end of the tubular shell; 21-The inserted end; 22-The exposed end. Detailed Implementation

[0043] The primary challenge in using fiber optic probes for dynamic monitoring of oil and gas wells is ensuring their reliability under high-temperature and high-pressure downhole environments. Existing high-reliability fiber optic probes for gas holdup measurement are manufactured using gold-based solder brazing sealing technology, capable of withstanding temperatures up to 150℃ and pressures up to 100MPa. Solder brazing sealing technology involves simultaneously heating a filler metal (below the melting point of the workpiece) and the workpiece to the filler metal's melting temperature, then using the liquid filler metal to fill the gaps in the solid workpiece to achieve a metal-to-metal connection.

[0044] Brazing sealing refers to heating the workpiece within a vacuum chamber, primarily used for welding products requiring high quality and easily oxidized materials. However, in practical applications, fiber optic probes are easily damaged by impacts from sand and debris in wells, making them consumables. Furthermore, the brazing sealing process requires a vacuum environment, leading to complex probe manufacturing processes and high production costs.

[0045] Example 1

[0046] This application provides a method for manufacturing an optical fiber probe, addressing the problem that the brazing sealing process for optical fiber probes requires a vacuum environment, resulting in complex manufacturing processes and high costs. The method is described below. Figure 1 As shown, Figure 1 A flowchart illustrating a method for fabricating an optical fiber probe, as shown in an exemplary embodiment of this application, includes the following steps:

[0047] S100: Insert the optical fiber 2 into the tubular housing 1, with a preset distance reserved between the insertion end 21 of the optical fiber 2 and the end 12 of the tubular housing.

[0048] Reference Figure 2 As shown, Figure 2 This is a schematic diagram illustrating the operation of inserting an optical fiber into a tubular housing in an exemplary embodiment of this application. Generally, there are two optical fibers 2, which are placed side by side into the tubular housing 1. The tubular housing 1 is generally a metal part. The optical fibers 2 are selected from high-temperature resistant optical fibers, such as polyimide-coated optical fibers, carbon-coated pure silicon optical fibers, or aluminized pure silicon optical fibers.

[0049] The polyimide coated on the optical fiber refers to a type of heterocyclic polymer containing imine groups in its macromolecular backbone. It possesses characteristics such as corrosion resistance, fatigue resistance, damage resistance, and impact resistance, as well as excellent high and low temperature performance, remaining undeformed for extended periods at -269℃ to 280℃. Carbon-coated pure silicon optical fibers or aluminized pure silicon optical fibers also exhibit high-temperature resistance. Therefore, in the application scenario described in this application, the optical fiber probe is not easily damaged by high temperatures. Similarly, the tubular outer shell 1, made of metal, also increases the pressure resistance of the optical fiber probe and extends its service life.

[0050] S200: Insert the dispensing head 3 of the dispensing machine 4 into the end 12 of the tubular housing, and inject optical conductive adhesive into the tubular housing 1 from the end 12 of the tubular housing.

[0051] Reference Figure 3 As shown, Figure 3 This is a schematic diagram illustrating the operation of injecting optical conductive adhesive into a tubular shell in an exemplary embodiment of this application. The optical conductive adhesive used in this embodiment is 353ND adhesive. 353ND is a two-component thermosetting epoxy resin with a solid content of 100% for use under high temperature conditions. It can work continuously at 200°C and can withstand high temperatures of 300-400°C for several hours without changing its performance. 353ND adhesive is resistant to dissolution and corrosion by a variety of solvents and chemicals, and is an ideal adhesive for bonding optical fibers, metals, glass, ceramics and most plastics.

[0052] Furthermore, 353ND adhesive has a long working time and is easy to use. In this embodiment, it facilitates subsequent operations and avoids problems such as adhesive deterioration. 353ND adhesive has strong fluidity and can penetrate into the fiber bundle when a large number of optical fibers are inserted, preventing the optical fibers from failing to bond firmly.

[0053] It is understood that in this embodiment of the application, 353ND needs to be prepared in the proportion of two components and filled into the dispensing machine 4. The dispensing head 3 on the dispensing machine 4 matches the size of the tubular outer shell 1. The dispensing machine 4 is used to control the start and stop of dispensing, which can better control the amount of dispensing.

[0054] S300: After the optical guide adhesive fills the space formed by the preset spacing, stop the dispensing and move the extension end 21 to contact the dispensing head 3.

[0055] Continue to refer to Figure 3 As shown, the preset spacing in this embodiment is to ensure the amount of adhesive injected in the subsequent adhesive injection process, preventing excessive or insufficient injection. (Refer to...) Figure 2 As shown, for example, the preset spacing can be 100mm-150mm. This length of adhesive can meet the requirements of strong bonding and compressive strength of the fiber optic probe during use. At 150mm, the amount of adhesive is relatively large, which can meet the greater pressure resistance requirements. Exceeding 150mm will not significantly improve the performance of the fiber optic probe and will result in a waste of production materials. 100mm can meet the basic pressure resistance requirements and ensure strong bonding. Less than 100mm cannot meet the compressive strength of the fiber optic probe. Therefore, a spacing greater than 100mm should be reserved. For example, when the reserved spacing is 125mm, it can be applied to most environmental conditions, and the bonding is strong and durable without wasting the amount of optical conductive adhesive. In addition, this spacing range is relatively large, which is easy for the operator to control, and does not require too much operation time to ensure the accuracy of the preset spacing, thus improving work efficiency.

[0056] In some examples, when filling the optical conductive adhesive, it can be observed whether the optical conductive adhesive contacts the insertion end 21 of the optical fiber 2, or whether the insertion end 21 of the optical fiber 2 moves. It can be determined that the optical conductive adhesive has filled the space formed by the preset spacing. At this time, the dispensing machine 4 stops dispensing. At this time, the insertion end 21 of the optical fiber 2 only contacts a small amount of optical conductive adhesive, which is not enough to complete the bonding. Therefore, the insertion end 21 of the optical fiber 2 is moved towards the end 12 of the tubular shell until it contacts the dispensing head 3. At this time, a part of the insertion end 21 of the optical fiber 2 that is equal to or less than the preset spacing length is mixed with the optical conductive adhesive, which can meet the bonding requirements. After curing, the optical fiber 2 is also more secure.

[0057] S400: Remove the injection head 3 from the tubular housing 1, and insert the sapphire pillar 5 from the end 12 of the tubular housing until the end face of the sapphire pillar 5 contacts the insertion end 21.

[0058] Reference Figure 3 and Figure 4 As shown, Figure 4This is an exemplary embodiment of the present application illustrating the operation of inserting a sapphire pillar into a tubular housing. After the dispensing head 3 is removed, the sapphire pillar 5 should be immediately inserted so that the sapphire pillar 5 contacts both the optical conductive adhesive and the insertion end 21 of the optical fiber 2. Typically, the distance between the dispensing head 3 and the end 12 of the tubular housing is shorter than the length of the sapphire pillar 5. After the sapphire pillar 5 is placed into the tubular housing 1, it can be pushed further into the tubular housing 1 according to the length of the sapphire pillar 5 itself. At this time, it can be ensured that the sapphire pillar 5 is in complete contact with the optical conductive adhesive and the optical fiber 2, preventing the possibility of gaps after bonding.

[0059] S500: The optical conductive adhesive is cured at low temperature to form an optical fiber probe.

[0060] Reference Figure 5 As shown, Figure 5 This diagram illustrates a low-temperature curing process for optical conductive adhesive, as shown in an exemplary embodiment of this application. In this embodiment, the 353ND adhesive changes from amber to deep red after curing. Therefore, the color change after curing allows for confirmation of complete curing, preventing issues with adhesive curing quality caused by errors in temperature or time control. 353ND adhesive is generally cured at a temperature slightly above room temperature. Once curing is complete, the fiber optic probe is fabricated and ready for use.

[0061] In some embodiments of this application, the optical conductive adhesive is cured at a temperature of 75°C-85°C for 25-35 minutes. For example, at 75°C, the curing time is 35 minutes; at 80°C, the curing time is 30 minutes; and at 85°C, the curing time is 25 minutes. The curing temperature and time can be adjusted as needed.

[0062] It is understandable that optical conductive adhesives have various curing methods, and curing temperatures can exceed 85°C, resulting in shorter curing times. These times can be adjusted appropriately based on the type of optical conductive adhesive. Taking the 353ND adhesive used in this embodiment as an example, the curing time is 40-60 minutes at 60°C, 5-15 minutes at 100°C, and 2-5 minutes at 120°C. It can be seen that the higher the curing temperature of the 353ND adhesive, the shorter the curing time. In this embodiment, the temperature and time can be adjusted according to the curing status of the optical conductive adhesive and the required efficiency.

[0063] In this embodiment, when selecting a heating device for low-temperature curing, a completely sealed structure can be used. This allows the entire fiber optic probe to be placed inside the device, and the temperature and time to be set. Once the operating time is reached, the probe can be removed to confirm the curing effect. Alternatively, a semi-enclosed structure can be used, placing the portion of the fiber optic probe containing the optical conductive adhesive inside the device while the other portion remains exposed outside. After setting the temperature, the curing time and the appearance of the optical conductive adhesive are used to determine whether the curing is complete. This method allows for continuous monitoring of the curing status of the optical conductive adhesive within the fiber optic probe, saving time spent switching the device on and off.

[0064] Understandably, the equipment used for heat curing can be equipped with temperature control instruments, making the operation of the equipment simpler, faster and more effective. Since the temperature is adjustable and can be kept constant, fiber optic probes can be fed in batches for curing.

[0065] As can be seen from the above, this application provides a method for manufacturing an optical fiber probe, including: inserting an optical fiber 2 into a tubular shell 1, with a preset distance reserved between the insertion end 21 of the optical fiber 2 and the end 12 of the tubular shell; inserting the dispensing head 3 of a dispensing machine 4 from the end 12 of the tubular shell and injecting optical conductive adhesive from the end 12 of the tubular shell into the tubular shell 1; stopping the dispensing after the optical conductive adhesive fills the space formed by the preset distance, and moving the insertion end 21 to contact the dispensing head 3; removing the dispensing head 3 from the tubular shell 1, inserting a sapphire pillar 5 from the end 12 of the tubular shell until the end face of the sapphire pillar 5 contacts the insertion end 21; and curing the portion of the tubular shell 1 containing the optical conductive adhesive at low temperature to finally form an optical fiber probe.

[0066] This method uses optical conductive adhesive to fix the optical fiber 2, tubular shell 1, and sapphire pillar 5, eliminating the need for operation in a vacuum environment, thus reducing the manufacturing cost of the optical fiber probe. Furthermore, this method allows for faster manufacturing and improves production efficiency.

[0067] Example 2

[0068] Reference Figure 6 As shown, Figure 6 The flowchart illustrates a method for fabricating an optical fiber probe, as shown in another exemplary embodiment of this application. Based on Embodiment 1, in some embodiments of this application, after inserting the optical fiber 2 into the tubular housing 1, the method includes the following steps:

[0069] S105: The exposed end 22 of the optical fiber 2 is detachably fixed to the first end 11 of the tubular shell.

[0070] In step S100, a preset distance needs to be reserved between the insertion end 21 of the optical fiber 2 and the end 12 of the tubular shell. This preset distance is used to control the amount of adhesive injected. Therefore, the relative position of the optical fiber 2 in the tubular shell 1 should remain unchanged. In this embodiment, the exposed end 22 of the optical fiber 2 is detachably fixed to the first end 11 of the tubular shell to ensure that the preset distance between the insertion end 21 of the optical fiber 2 and the end 12 of the tubular shell remains unchanged during the adhesive injection process.

[0071] The detachable fixing method can be achieved by temporarily attaching the fiber 2 with adhesive tape or by fixing the fiber 2 with a clamp. After temporary fixing, the distance between the fiber 2 and the end 12 of the tubular outer shell can remain unchanged. Then, when applying adhesive, it can be ensured that the amount of adhesive applied when it comes into contact with the fiber 2 meets the requirements.

[0072] In step S300, after stopping the dispensing, the following steps are also included:

[0073] Disassemble and separate the exposed end 22 of the optical fiber 2 from the first end 11 of the tubular outer shell.

[0074] In step S300, since it is necessary to further insert the optical fiber 2 into the tubular housing 1, the optical fiber 2 can be separated from the first end 11 of the tubular housing. That is, the adhesive tape can be removed or the clamp can be removed. After separating the optical fiber 2 from the first end 11 of the tubular housing, the operator holds the exposed end of the optical fiber 2 by hand or by using a clamp, and gradually moves the optical fiber 2 closer to the end 12 of the tubular housing until the inserted end 21 of the optical fiber 2 contacts the dispensing head 3.

[0075] Example 3

[0076] Reference Figure 7 As shown, Figure 7 The flowchart illustrates a method for fabricating an optical fiber probe in another exemplary embodiment of this application. Based on the above-described Embodiment 1 or Embodiment 2, in some embodiments of this application, after inserting the sapphire pillar 5 from the end 12 of the tubular shell until the end face of the sapphire pillar 5 contacts the insertion end 21, the following steps are included:

[0077] S305: Apply epoxy resin adhesive to the edge of the contact point between the sapphire pillar 5 and the tubular outer shell 1.

[0078] Because there may be gaps between the sapphire pillar 5 and the tubular shell 1, the adhesion is poor before the optical conductive adhesive is fully cured. There is a risk that the sapphire pillar 5 may detach from the tubular shell 1. Simultaneously, the optical conductive adhesive has a certain degree of fluidity and may flow out from the gaps between the sapphire pillar 5 and the tubular shell 1, affecting the quality of the finished optical probe. Epoxy resin adhesive generally refers to adhesives made primarily of epoxy resin. Epoxy resin adhesives have a wide range of applications and can bond various metals and alloys, as well as non-metallic materials such as ceramics, glass, and bamboo. They can also be used for bonding metals and non-metallic materials.

[0079] In this embodiment, epoxy resin is applied to the edge of the contact area between the sapphire pillar 5 and the tubular outer shell 1 to ensure that the sapphire pillar 5 will not fall off the tubular outer shell 1 and that no optical conductive adhesive will flow out from inside.

[0080] In some embodiments of this application, step S500, after the optical conductive adhesive is cured at low temperature, further includes:

[0081] The epoxy resin adhesive is removed at high temperature.

[0082] The epoxy resin adhesive is removed after the optical conductive adhesive has cured. The temperature at which the epoxy resin adhesive is removed is higher than the curing temperature of the optical conductive adhesive. Therefore, during the curing period of the optical conductive adhesive, the epoxy resin adhesive can also play an adhesive role, which can ensure that the optical conductive adhesive is completely cured before heating and removal, and saves preheating time. The removal method is simple and quick.

[0083] In some embodiments of this application, the temperature for removing the epoxy resin adhesive is 145℃-155℃, and the removal time is 3min-7min. For example, at 145℃, the heating time is 7min; at 155℃, the heating time is 3min; and at 150℃, the heating time is 5min. The temperature and time for removing the epoxy resin adhesive can be adjusted as needed.

[0084] The removal temperature of epoxy resin adhesive should be higher than that of optical conductive adhesive. After the optical conductive adhesive has cured, the epoxy resin adhesive can be removed by directly raising the temperature. Similarly, the removal temperature and time will vary depending on the type of epoxy resin. The temperature can be adjusted according to the type of epoxy resin selected. Epoxy resin adhesive will melt after being heated to a high temperature. At this time, the epoxy resin adhesive can be wiped clean with a paper towel or special tools.

[0085] In some embodiments of this application, the optical conductive adhesive is cured at a temperature of 75°C-85°C for a curing time of 25 min-35 min.

[0086] It is understandable that optical conductive adhesives have various curing methods, and curing can also be carried out at temperatures above 85°C, which will correspondingly shorten the curing time. Appropriate adjustments can be made according to the type of optical conductive adhesive. Taking the 353ND adhesive used in this application embodiment as an example, the curing time is 40-60 minutes at 60°C; 5-15 minutes at 100°C; and 2-5 minutes at 120°C. It can be seen that the higher the curing temperature of the 353ND adhesive, the shorter the curing time required.

[0087] However, excessively high temperatures may cause the epoxy resin to melt, resulting in the sapphire pillar 5 falling off unexpectedly before it is fully cured, or the sapphire pillar 5 sliding and separating from the optical fiber 2. Therefore, while ensuring curing efficiency, the temperature difference between the curing of the optical conductive adhesive and the removal of the epoxy resin is increased, so that the epoxy resin can still maintain adhesion during the curing of the optical conductive adhesive, without affecting the quality of the finished product. In this application, since the optical conductive adhesive has a certain length in the tubular shell, a low-temperature curing method is used to ensure uniform curing and good curing effect, which can improve the quality of the finished fiber optic probe.

[0088] It is understandable that, in addition to using epoxy resin to seal the gap between the sapphire pillar 5 and the tubular shell 1, the same effect can also be achieved by adjusting the dimensional tolerances of the sapphire pillar 5 and the tubular shell 1, or by designing fixtures, etc. This application does not make any special requirements.

[0089] Continue to refer to Figure 5 As shown in the embodiment of this application, the optical conductive adhesive is cured at low temperature using oven 6; then the temperature of oven 6 is increased to remove the epoxy resin adhesive. The outer shell of oven 6 is generally made of thin steel plate with a painted surface, while the working chamber of oven 6 is made of high-quality structural steel plate. The heater is installed at the bottom, but can also be placed at the top or sides.

[0090] Furthermore, when removing epoxy resin adhesive, the temperature of oven 6 can be directly increased. Since the optical conductive adhesive has been cured, the preheating time of oven 6 can be saved, and the epoxy resin adhesive can be removed after a short heating time.

[0091] It is understandable that, besides oven 6, other temperature-adjustable and temperature-controlled heating tools can be used to cure the optical conductive adhesive and remove the epoxy resin, such as a hot air gun; this application does not impose any special restrictions. Furthermore, because the optical conductive adhesive is fluid, if the fiber optic probe is tilted, the optical conductive adhesive will also flow in the tilted direction, ultimately causing the cured surface to tilt and rendering it unusable. Therefore, when placing the fiber optic probe in oven 6 or any heating device, it should be kept vertical, generally using clamps for holding and fixing.

[0092] Example 4

[0093] Based on any of the above embodiments, refer to Figure 8 As shown, Figure 8 A flowchart illustrating a method for fabricating an optical fiber probe, as shown in another exemplary embodiment of this application, may include the following steps before inserting the optical fiber 2 into the tubular housing 1 in some embodiments of this application:

[0094] S001: After vacuum degassing or centrifugal degassing, the optical conductive adhesive is placed into the dispensing machine 4.

[0095] Optical conductive adhesive is a two-component liquid. When not in use, the two components are stored separately. When it is to be used, the two components should be mixed evenly according to the mixing ratio. During mixing, the optical conductive adhesive needs to be stirred. At this time, air will be mixed in and form bubbles in the adhesive. If the bubbles are not treated, a large number of small air cavities will be formed after the optical conductive adhesive cures, affecting the curing quality and bonding effect.

[0096] Therefore, before placing the optical conductive adhesive into the dispensing machine 4, degassing is required. This can be done using vacuum degassing or centrifugal degassing. Vacuum degassing utilizes the decrease in external pressure, causing the bubbles to increase in volume and rise to the surface to burst. Centrifugal degassing uses centrifugal force to allow the lighter bubbles to reach the liquid surface. After degassing, there will be no residual air in the optical conductive adhesive, and it will not affect the bonding and sealing performance after curing.

[0097] In some embodiments of this application, before inserting the optical fiber 2 into the tubular housing 1, the following steps are further included:

[0098] S005: Perform pretreatment on optical fiber 2 and sapphire pillar 5. The pretreatment includes polishing both ends of optical fiber 2 and sapphire pillar 5.

[0099] To reduce optical intensity loss during optical transmission and improve the reliability of the optical fiber transmission system, fiber optic probes require polishing of fiber optic cable 2 and sapphire pillar 5. Additionally, it's necessary to remove as much of the altered layer as possible from the end face of fiber optic cable 2 and test for scratches or other contamination. Finally, the goal is to achieve low insertion loss and high return loss. Therefore, the polishing process of fiber optic cable 2 is crucial for improving optical performance.

[0100] In some embodiments of this application, after polishing both ends of the optical fiber 2 and both ends of the sapphire pillar 5, the following steps are also included:

[0101] S010: Clean the optical fiber 2, sapphire pillar 5 and tubular shell 1. The cleaning process includes ultrasonic cleaning of the tubular shell 1, the polished optical fiber 2 and the polished sapphire pillar 5. The cleaning agent for ultrasonic cleaning is acetone or alcohol.

[0102] Ultrasonic cleaning utilizes the cavitation, acceleration, and direct flow effects of ultrasound waves in liquids to directly and indirectly act on the liquid and contaminants, dispersing, emulsifying, and peeling off the contaminant layer to achieve the cleaning purpose. The principle of an ultrasonic cleaner involves a high-frequency oscillation signal emitted by an ultrasonic generator. The ultrasound waves generate tens of thousands of tiny bubbles in the cleaning fluid, which vibrate under the influence of the sound field.

[0103] These bubbles form and grow in the negative pressure zone where the ultrasound propagates longitudinally. In the positive pressure zone, when the sound pressure reaches a certain value, the bubbles rapidly enlarge and then suddenly collapse. This bubble collapse generates high temperatures of several hundred degrees Celsius and instantaneous high pressures exceeding 1000 atmospheres. The continuous generation of these instantaneous high pressures is like a series of small "explosions" constantly impacting the object's surface, causing dirt and grime to rapidly peel off, thus achieving the purpose of cleaning and purifying the object's surface. In this embodiment, ultrasonic cleaning can remove dust, fingerprints, and other deposits from the surfaces of the optical fiber 2, sapphire pillar 5, and tubular outer shell, making the optical adhesive bonding more secure.

[0104] Secondly, after polishing, polishing paste will remain on the surfaces of optical fiber 2 and sapphire pillar 5. Generally, polishing paste is often made with paraffin wax. Paraffin wax has a large molecular weight and a high melting point, and is solid at room temperature, making it difficult to clean. Traditional methods such as cleaning with organic solvents or boiling in high-temperature alkaline water have many drawbacks. Ultrasonic cleaning, however, can thoroughly clean the workpiece surface within minutes under medium-temperature conditions, avoiding polishing paste residue. The selected alcohol and acetone are colorless, volatile, and flammable organic solvents, used as highly efficient degreasing agents, which can remove contaminants without residue in an ultrasonic cleaner.

[0105] As can be seen from the above embodiments, continuing to refer to... Figure 8 As shown, this application also provides methods for fabricating fiber optic probes in other embodiments, including the following steps:

[0106] S001: After vacuum degassing or centrifugal degassing, the optical conductive adhesive is placed into the dispensing machine 4.

[0107] S005: Perform pretreatment on optical fiber 2 and sapphire pillar 5. The pretreatment includes polishing both ends of optical fiber 2 and sapphire pillar 5.

[0108] S010: Clean the optical fiber 2, sapphire pillar 5 and tubular shell 1. The cleaning process includes ultrasonic cleaning of the tubular shell 1, the polished optical fiber 2 and the polished sapphire pillar 5. The cleaning agent for ultrasonic cleaning is acetone or alcohol.

[0109] S100: Insert the optical fiber 2 into the tubular housing 1, with a preset distance reserved between the insertion end 21 of the optical fiber 2 and the end 12 of the tubular housing.

[0110] S105: The exposed end 22 of the optical fiber 2 is detachably fixed to the first end 11 of the tubular shell.

[0111] S200: Insert the dispensing head 3 of the dispensing machine 4 into the end 12 of the tubular housing, and inject optical conductive adhesive into the tubular housing 1 from the end 12 of the tubular housing.

[0112] S300: After the optical conductive adhesive fills the space formed by the preset spacing, stop the adhesive injection, disassemble the exposed end 22 of the optical fiber 2 from the first end 11 of the tubular shell, and move the extended end 21 to contact the adhesive injection head 3.

[0113] S305: Apply epoxy resin adhesive to the edge of the contact point between the sapphire pillar 5 and the tubular outer shell 1.

[0114] S400: Remove the injection head 3 from the tubular housing 1, and insert the sapphire pillar 5 from the end 12 of the tubular housing until the end face of the sapphire pillar 5 contacts the insertion end 21.

[0115] S500: The optical conductive adhesive is cured at low temperature in oven 6, and then the temperature of oven 6 is increased to remove the epoxy resin adhesive at high temperature, finally forming the optical fiber probe.

[0116] As can be seen from the above, this application provides another embodiment of the method for manufacturing an optical fiber probe. In this method, the exposed end 22 of the optical fiber 2 can be detachably fixed to the first end 11 of the tubular shell, providing a reference amount of adhesive for the adhesive injection. By applying epoxy resin adhesive to the edge of the contact position between the sapphire pillar 5 and the tubular shell 1, the sapphire pillar 5 is prevented from falling off or the optical adhesive from flowing out. The pretreatment and cleaning of the optical fiber 2, sapphire pillar 5 and tubular shell 1 can improve the quality of the finished product. The method of this embodiment does not need to be operated in a vacuum environment, which reduces the manufacturing cost of the optical fiber probe, improves efficiency, and also ensures the quality of the optical probe. Moreover, the steps are simple and easy to operate, making the quality and efficiency controllable.

[0117] This application also provides an optical fiber probe, manufactured using the method for fabricating an optical fiber probe according to any of the above embodiments; see reference. Figure 9 As shown, Figure 9 This is a schematic diagram of the structure of an optical fiber probe shown in an exemplary embodiment of this application. The optical fiber probe includes: an optical fiber 2, a tubular shell 1, optical conductive adhesive, and a sapphire pillar 5.

[0118] The optical fiber 2 and the sapphire pillar 5 are both located inside the tubular shell 1, and the sapphire pillar 5 is located at the end 12 of the tubular shell and is in contact with the insertion end 21 of the optical fiber 2; the optical conductive adhesive is filled between the part of the optical fiber 2 near the sapphire pillar 5 and the tubular shell 1, and the length of the optical conductive adhesive along the extension direction of the optical fiber 2 is equal to or less than the preset spacing.

[0119] The fiber optic probe in this embodiment is made by bonding an optical fiber 2, a sapphire pillar 5, and a tubular outer shell 1 with optical conductive adhesive. The optical conductive adhesive has a certain length, which can ensure that the optical fiber 2, the sapphire pillar 5, and the tubular outer shell 1 are firmly bonded and do not fall off. In addition, the sapphire pillar 5 has good light transmission performance and can achieve detection function when used with the optical fiber 2. It has good light transmission effect, simple structure, and low production cost.

[0120] As can be seen from the above, this application provides a method for manufacturing an optical fiber probe, comprising: inserting an optical fiber into a tubular shell, with a preset gap between the inserted end of the optical fiber and the end of the tubular shell; inserting the dispensing head of a dispensing machine from the end of the tubular shell and injecting optical conductive adhesive into the tubular shell from the end of the tubular shell; stopping the dispensing after the optical conductive adhesive fills the space formed by the preset gap, and moving the inserted end to contact the dispensing head; removing the dispensing head from the tubular shell, inserting a sapphire pillar from the end of the tubular shell until the end face of the sapphire pillar contacts the inserted end; and curing the portion of the tubular shell containing the optical conductive adhesive at a low temperature to finally form an optical fiber probe.

[0121] This application also provides an optical fiber probe, which includes an optical fiber, a tubular shell, optical conductive adhesive, and a sapphire pillar. Both the optical fiber and the sapphire pillar are located within the tubular shell, with the sapphire pillar positioned at the end of the shell and contacting the insertion end of the optical fiber. The optical conductive adhesive fills the space between the portion of the optical fiber near the sapphire pillar and the tubular shell, with the length of the adhesive along the optical fiber's extension direction equal to or less than a preset spacing. This application uses optical conductive adhesive to fix the optical fiber, tubular shell, and sapphire pillar, eliminating the need for operation in a vacuum environment, thus reducing the manufacturing cost of the optical fiber probe. Furthermore, this method allows for faster fabrication and improves efficiency.

[0122] It should be noted that the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a structure, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a structure, article, or apparatus. Without further limitations, an element defined by the phrase "comprising..." does not exclude the presence of other identical elements in the structure, article, or apparatus that includes said element.

[0123] Other embodiments of this disclosure will readily occur to those skilled in the art upon consideration of the specification and practice of the disclosure herein. This application is intended to cover any variations, uses, or adaptations of this disclosure that follow the general principles of this disclosure and include common knowledge or customary techniques in the art not disclosed herein. The specification and embodiments are to be considered exemplary only, and the true scope and spirit of this disclosure are indicated by the following claims. The above detailed embodiments further illustrate the purpose, technical solutions, and beneficial effects of the embodiments of this application. It should be understood that the above are merely specific embodiments of the embodiments of this application and are not intended to limit the scope of protection of the embodiments of this application. Any modifications, equivalent substitutions, improvements, etc., made based on the technical solutions of the embodiments of this application should be included within the scope of protection of the embodiments of this application.

Claims

1. A method for fabricating an optical fiber probe, characterized in that, include: Insert the optical fiber (2) into the tubular shell (1), and fix the exposed end (22) of the optical fiber (2) to the first end (11) of the tubular shell in a detachable manner. A preset distance is reserved between the inserted end (21) of the optical fiber (2) and the end (12) of the tubular shell. Insert the dispensing head (3) of the dispensing machine (4) from the end (12) of the tubular housing, and inject optical conductive adhesive from the end (12) of the tubular housing into the tubular housing (1); After the optical conductive adhesive fills the space formed by the preset spacing, stop the adhesive injection, detach the exposed end (22) of the optical fiber (2) from the first end (11) of the tubular shell, and move the inserted end (21) to contact the adhesive injection head (3); Remove the injection head (3) from the tubular housing (1), insert the sapphire pillar (5) from the end (12) of the tubular housing until the end face of the sapphire pillar (5) contacts the insertion end (21); The optical conductive adhesive is cured at low temperature to form an optical fiber probe.

2. The method for fabricating an optical fiber probe according to claim 1, characterized in that, The preset spacing is 100mm-150mm.

3. The method for fabricating an optical fiber probe according to claim 1, characterized in that, The process of inserting the sapphire pillar (5) from the end (12) of the tubular outer shell until the end face of the sapphire pillar (5) contacts the inserted end (21) includes: Apply epoxy resin adhesive to the edge of the contact position between the sapphire pillar (5) and the tubular outer shell (1); After the optical conductive adhesive is cured at low temperature, the process further includes: removing the epoxy resin adhesive at high temperature.

4. The method for fabricating an optical fiber probe according to claim 3, characterized in that, The temperature for removing the epoxy resin adhesive is 145℃-155℃, and the removal time is 3min-7min.

5. The method for fabricating an optical fiber probe according to claim 3, characterized in that, The optical conductive adhesive is cured at low temperature in an oven (6); then the temperature of the oven (6) is increased to remove the epoxy resin adhesive.

6. The method for fabricating an optical fiber probe according to claim 5, characterized in that, The optical conductive adhesive is cured at a temperature of 75℃-85℃ for a duration of 25min-35min.

7. The method for fabricating an optical fiber probe according to any one of claims 1-6, characterized in that, Before inserting the optical fiber (2) into the tubular housing (1), the procedure includes: After vacuum degassing or centrifugal degassing, the optical conductive adhesive is placed into the dispensing machine (4).

8. A method for fabricating an optical fiber probe according to any one of claims 1-6, characterized in that, Before inserting the optical fiber (2) into the tubular housing (1), the procedure further includes: The optical fiber (2) and the sapphire pillar (5) are pre-processed, and the pre-processing includes polishing the two ends of the optical fiber (2) and the two ends of the sapphire pillar (5). The optical fiber (2), the sapphire pillar (5) and the tubular shell (1) are cleaned. The cleaning process includes ultrasonic cleaning of the tubular shell (1), the polished optical fiber (2) and the polished sapphire pillar (5). The cleaning agent for ultrasonic cleaning is acetone or alcohol.

9. An optical fiber probe, characterized in that, The fiber optic probe is manufactured using the method described in any one of claims 1-8; the fiber optic probe includes an optical fiber (2), a tubular shell (1), optical conductive adhesive, and a sapphire pillar (5); The optical fiber (2) and the sapphire pillar (5) are both located inside the tubular shell (1), and the sapphire pillar (5) is located at the end (12) of the tubular shell and is in contact with the insertion end (21) of the optical fiber (2). The optical conductive adhesive is filled between the portion of the optical fiber (2) near the sapphire pillar (5) and the tubular outer shell (1), and the length of the optical conductive adhesive along the extension direction of the optical fiber (2) is equal to or less than a preset spacing.

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