A liquid sealing method for FP optical fiber sensor

Abstract

The present invention discloses a liquid-sealing method for an FP fiber optic sensor, comprising the steps of: inserting an FP interferometer on the FP fiber optic sensor into a hollow cavity of a packaging container through an optical fiber channel; sealing and securing the FP fiber optic sensor to the optical fiber channel; injecting encapsulating liquid into the hollow cavity of the packaging container through an injection channel, such that the encapsulating liquid at least submerges the FP interferometer on the FP fiber optic sensor; and sealing the injection channel. This liquid-sealing method can encapsulate the FP fiber optic sensor in the encapsulating liquid, thereby reducing the nonlinearity of the FP fiber optic sensor.

Description

Technical Field

[0001] The present invention relates to the field of sensor packaging, and in particular to a liquid sealing method for an FP optical fiber sensor. Background Art

[0002] The FP fiber optic sensor is a point-type fiber optic sensor based on the Fabry–Pérot (FP) cavity. It can be used to measure physical parameters at a single node, such as pressure, temperature, magnetic field, electric field, etc. It performs particularly well in measuring pressure and temperature, and its minimum diameter can reach 125μm, making it suitable for many fields.

[0003] Patents such as CN209166680U and CN206627147U disclose that an optical cavity and a sensing film are sequentially fabricated on the end of an optical fiber to form an FP optical fiber sensor. The end face of the optical fiber, the optical cavity, and the sensing film are used to form an FP interferometer. The end face of the optical fiber reflects the light within the optical fiber to form a first beam of reflected light, and the inner surface of the sensing film reflects the light within the optical cavity to form a second beam of reflected light. The two beams of reflected light interfere with each other to form an interference light signal. When the sensing film interacts with the physical parameter to be measured, parameters such as the cavity length or resonant frequency of the optical cavity will change, thereby causing the interference light signal to drift. The change in the physical parameter to be measured can be calculated based on the drift of the interference light signal.

[0004] However, the inventors of the present application have discovered that, regardless of whether quartz or graphene is used as the sensing film constituting the FP interferometer, part of the light in the optical cavity will be transmitted into the sensing film, and the light in the sensing film will be reflected by the outer surface of the sensing film to form a third beam of reflected light, which will affect the interference light signal and cause the nonlinearity of the measurement waveform. This will introduce errors and noise when the measurement waveform is restored by the demodulation system, and the nonlinearity of the measurement waveform will increase with the thickness of the sensing film, seriously affecting the measurement accuracy of the FP fiber optic sensor. Summary of the Invention

[0005] In order to address the above-mentioned deficiencies in the prior art, the present invention provides a liquid sealing method, which can encapsulate an FP optical fiber sensor in a sealing liquid to reduce the nonlinearity of the FP optical fiber sensor.

[0006] The technical problem to be solved by the present invention is achieved through the following technical solutions:

[0007] A liquid sealing method for an FP optical fiber sensor comprises the following steps:

[0008] Step 200: inserting the FP interferometer on the FP fiber optic sensor into the hollow cavity of the packaging container through the fiber optic channel;

[0009] Step 300: Sealing and fixing the FP optical fiber sensor to the optical fiber channel;

[0010] Step 400: injecting a packaging liquid into the hollow cavity of the packaging container through a liquid injection channel, so that the packaging liquid at least submerges the FP interferometer on the FP optical fiber sensor;

[0011] Step 500: Seal the injection channel.

[0012] Furthermore, in step 200, the packaging container is placed with the hollow cavity and the optical fiber channel in a vertical direction and the entrance of the optical fiber channel facing upward, and the FP optical fiber sensor is vertically inserted into the optical fiber channel with the FP interferometer facing downward, so that the FP interferometer on the FP optical fiber sensor directly reaches the hollow cavity.

[0013] Furthermore, in step 300, the FP optical fiber sensor and the optical fiber channel are sealed and fixed by using sealant.

[0014] Furthermore, in step 400, the packaging container is placed with the hollow cavity and the liquid injection channel in a vertical direction and the inlet of the liquid injection channel facing upward, and the packaging liquid is dripped into the liquid injection channel in a vertical direction using a dropper, so that the packaging liquid reaches the hollow cavity directly under the action of gravity.

[0015] Furthermore, in step 500, the injection channel is sealed using a sealer.

[0016] Furthermore, the sealer includes a sealing portion and a limiting portion connected in the axial direction, the diameter of the limiting portion is larger than the diameter of the sealing portion, so that the sealer forms a stepped structure with a two-level cylinder; the diameter of the sealing portion is adapted to the caliber of the injection channel, so that the sealing portion of the sealer can extend into the injection channel, and when the sealing portion extends into the injection channel to a predetermined depth, the limiting portion of the sealer abuts against the outer surface of the packaging container, thereby limiting the sealing portion from continuing to extend into the injection channel.

[0017] Furthermore, the packaging container is composed of a channel portion, a cavity portion, and a sealing gasket, and before step 200, further comprises the following steps:

[0018] Step 100: Assemble the channel part, the cavity part and the sealing gasket together so that the injection channel and the optical fiber channel in the channel part are respectively connected to the hollow cavity in the cavity part, and the sealing gasket is clamped between the channel part and the cavity part.

[0019] Furthermore, the channel portion includes a first end portion and a first connecting portion, the first end portion and the first connecting portion are connected along the axial direction, and the injection channel and the optical fiber channel are arranged in the first end portion; the cavity portion includes a second end portion and a second connecting portion, the second end portion and the second connecting portion are connected along the axial direction, and the hollow cavity is arranged in the second connecting portion; the first connecting portion and the second connecting portion are relatively matched and connected.

[0020] Further, the first connecting part includes a connecting channel and a first connecting wall surrounding the outside of the connecting channel, one end of the connecting channel is connected to the injection channel and the optical fiber channel, and the other end is for the second connecting part to extend into, one end of the first connecting wall is connected to the first end, and the other end is opposite to the second connecting part; the second connecting part includes a support platform wall and a second connecting wall, one end of the support platform wall is connected to the second end, and the other end is connected to the second connecting wall, and the other end of the second connecting wall facing away from the support platform wall is opposite to the first connecting part; the support platform wall and the second connecting wall both surround the hollow cavity, and the thickness of the support platform wall is greater than the thickness of the second connecting wall, so that a step structure with a secondary annular wall is formed on the outer surface of the second connecting part; the outer diameter of the second connecting wall is matched with the inner diameter of the first connecting wall, so that the second connecting wall can extend into the connecting channel and then connect with the first connecting wall; when the second connecting wall extends into the connecting channel, the support platform wall faces one side end face of the first connecting wall, and together with the first connecting wall facing one side end face of the support platform wall, clamps the sealing gasket.

[0021] Furthermore, in step 100, the steps of assembling the channel portion, the cavity portion and the sealing gasket together are as follows:

[0022] Step 101: stacking the sealing gasket on the end surface of the support wall of the cavity portion facing the first connecting wall;

[0023] Step 102: Extend the second connecting wall of the cavity part into the connecting channel of the channel part, and connect it with the second connecting wall of the channel part until the end face of one side of the support platform wall faces the first connecting wall, and clamp the sealing gasket together with the end face of one side of the first connecting wall facing the support platform wall.

[0024] The present invention has the following beneficial effects: the liquid sealing method seals the FP interferometer on the FP optical fiber sensor in the encapsulating liquid. Compared with the prior art method of directly exposing the FP interferometer to the outside air, because the refractive index of the encapsulating liquid is greater than that of air, when light propagates to the interface between the sensing film and the encapsulating liquid, the scattering angle of the light becomes larger, the amount of light scattered into the encapsulating liquid increases, and the amount of light reflected back into the FP optical fiber sensor decreases. Therefore, interference with the interference light signal can be reduced, the nonlinearity of the FP optical fiber sensor is reduced, and measurement errors can be effectively eliminated. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 Schematic diagram of the structure of an existing FP optical fiber sensor.

[0026] Figure 2 This is a block diagram of the steps of the liquid sealing method provided by the present invention.

[0027] Figure 3 This is a relative schematic diagram of the packaging container, sealer and FP optical fiber sensor provided by the present invention when assembled.

[0028] Figure 4 This is a schematic structural diagram of the assembled packaging container, sealer, and FP optical fiber sensor provided by the present invention.

[0029] Figure 5 This is a schematic structural diagram of the packaging container provided by the present invention.

[0030] Figure 6 This is a cross-sectional schematic diagram of the packaging container provided by the present invention.

[0031] Figure 7 This is an exploded schematic diagram of the packaging container provided by the present invention. DETAILED DESCRIPTION

[0032] The present invention will be described in detail below with reference to the accompanying drawings and embodiments. Examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are intended to be used to explain the present invention, and are not to be construed as limiting the present invention.

[0033] In the description of the present invention, it should be understood that the terms "length", "width", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc., indicating the orientation or position relationship, are based on the orientation or position relationship shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention.

[0034] Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of the technical features being referred to. Thus, a feature identified as "first," "second," or "third" may explicitly or implicitly include one or more of such features. In the description of the present invention, "plurality" means two or more, unless otherwise specifically defined.

[0035] In the present invention, unless otherwise expressly specified or limited, terms such as "installed," "connected," "connect," "fixed," and "disposed" should be understood in a broad sense. For example, they may refer to fixed or detachable connections, or integration; mechanical or electrical connections; direct or indirect connections through an intermediate medium; or internal communication between two components or interaction between two components. Those skilled in the art will understand the specific meanings of the above terms in the present invention based on specific circumstances.

[0036] Example 1

[0037] A liquid sealing method for an FP optical fiber sensor is used for liquid packaging of the FP optical fiber sensor.

[0038] like Figure 1 As shown, the FP fiber sensor includes a single-mode optical fiber 110, an optical cavity 120, and a sensing film 130. One end of the optical cavity 120 is connected to the end face of the single-mode optical fiber 110, and the other end is connected to the sensing film 130. The end face of the single-mode optical fiber 110, the optical cavity 120, and the sensing film 130 together form an FP interferometer. The single-mode optical fiber 110 includes a core 111 and a cladding 112. The cladding 112 surrounds and wraps around the outer surface of the core 111. The refractive index of the core 111 is greater than the refractive index of the cladding 112, so that light can be totally reflected at the interface between the core 111 and the cladding 112, and is thereby confined to propagate axially within the core 111. The core 111 of the single-mode optical fiber 110 is aligned with the optical cavity 120.

[0039] The sensing film 130 can be a quartz film, a graphene film or a film of other materials; the optical cavity 120 can be formed by etching the end face of the single-mode optical fiber 110, or by fusing a hollow tube, a hollow core optical fiber or a quartz tube of a predetermined length on the end face of the single-mode optical fiber 110.

[0040] When the light in the single-mode optical fiber 110 propagates to the interface between the single-mode optical fiber 110 and the optical cavity 120, due to the difference in refractive index of the medium, part of the light is reflected by the end face of the single-mode optical fiber 110 back into the single-mode optical fiber 110, forming a first beam of reflected light, and part of the light enters the optical cavity 120 and continues to propagate forward. When the light in the optical cavity 120 propagates to the interface between the optical cavity 120 and the sensing film 130, due to the difference in refractive index of the medium, part of the light is reflected by the inner surface of the sensing film 130 back into the single-mode optical fiber 110, forming a second beam of reflected light, and part of the light enters the sensing film 130 and continues to propagate forward. When the light in the sensing film 130 propagates to the interface between the sensing film 130 and the external environment, due to the difference in refractive index of the medium, part of the light is reflected by the outer surface of the sensing film 130 back into the single-mode optical fiber 110, forming a third beam of reflected light, and the remaining light is scattered into the external environment.

[0041] The head end face of the single-mode optical fiber 110 is used to connect to an optical modulation and demodulation system. The optical modulation and demodulation system transmits a modulated optical signal into the FP optical fiber sensor and receives a reflected optical signal reflected from the FP optical fiber sensor. Due to the optical path difference, the first beam of reflected light and the second beam of reflected light will interfere with each other on the photoelectric sensor of the optical modulation and demodulation system to form an interference optical signal. When the sensing film 130 interacts with the physical parameter to be measured in the external environment, parameters such as the cavity length or resonant frequency of the optical cavity 120 will change, thereby causing the interference optical signal to drift. The drift of the interference optical signal is approximately linearly related to the change in the physical parameter to be measured.

[0042] However, the optical modulation and demodulation system actually also receives a third beam of reflected light reflected from the FP optical fiber sensor at the same time. The third beam of reflected light will affect the interference between the first beam of reflected light and the second beam of reflected light on the photoelectric sensor, resulting in nonlinearity of the measurement waveform, which will introduce errors and noise when the measurement waveform is demodulated and restored. Moreover, the nonlinearity of the measurement waveform will increase with the increase of the thickness of the sensing film 130, seriously affecting the measurement accuracy of the FP optical fiber sensor.

[0043] like Figure 2-4 As shown, the packaging method includes the following steps:

[0044] Step 200 : inserting the FP interferometer on the FP fiber optic sensor 100 into the hollow cavity 201 of the packaging container 200 through the fiber optic channel 203 .

[0045] In step 200 , a hollow cavity 201 and an optical fiber channel 203 are provided inside the packaging container 200 . One end of the optical fiber channel 203 is connected to the hollow cavity 201 , and the other end is connected to the external environment on the outer surface of the packaging container 200 .

[0046] Preferably, the hollow cavity 201 and the optical fiber channel 203 both extend along the axial direction of the packaging container 200, and the diameter of the optical fiber channel 203 should be slightly larger than the diameter (single-mode optical fiber 110) of the FP optical fiber sensor 100 to facilitate the insertion of the FP optical fiber sensor 100; the diameter of the optical fiber channel 203 is smaller than the diameter of the hollow cavity 201, and the optical fiber channel 203 is offset from the hollow cavity 201, that is, the central axis of the optical fiber channel 203 and the central axis of the hollow cavity 201 are not on the same straight line.

[0047] When inserting the FP fiber optic sensor 100, the packaging container 200 is placed with the hollow cavity 201 and the fiber optic channel 203 in a vertical direction and the entrance of the fiber optic channel 203 facing upward. The FP fiber optic sensor 100 is vertically inserted into the fiber optic channel 203 with the FP interferometer facing downward, so that the FP interferometer on the FP fiber optic sensor 100 directly reaches the hollow cavity 201.

[0048] Step 300 : Sealing and fixing the FP optical fiber sensor 100 to the optical fiber channel 203 .

[0049] In step 300, sealing and fixing the FP fiber optic sensor 100 to the fiber optic channel 203 has two purposes: one is to prevent the encapsulation liquid in the hollow cavity 201 from leaking outward from the gap between the FP fiber optic sensor 100 and the fiber optic channel 203; the other is to fix the relative position between the FP fiber optic sensor 100 and the packaging container 200 to prevent the FP interferometer of the FP fiber optic sensor 100 from falling out of the hollow cavity 201.

[0050] The FP optical fiber sensor 100 and the optical fiber channel 203 can be sealed and fixed using, but are not limited to, a sealant 400. During sealing, the sealant 400 is dropped onto the outer surface of the packaging container 200 and surrounding the entrance of the optical fiber channel 203, as well as the outer surface of the (single-mode optical fiber 110) of the FP optical fiber sensor 100, and then the sealant 400 is naturally cured, light-cured, or heat-cured.

[0051] Step 400 : injecting encapsulation liquid into the hollow cavity 201 of the encapsulation container 200 through the liquid injection channel 202 , so that the encapsulation liquid at least immerses the FP interferometer on the FP optical fiber sensor 100 .

[0052] In step 400 , a liquid injection channel 202 is further provided inside the packaging container 200 . One end of the liquid injection channel 202 is connected to the hollow cavity 201 , and the other end is connected to the external environment on the outer surface of the packaging container 200 .

[0053] Preferably, the injection channel 202 extends along the axial direction of the packaging container 200 , and the injection channel 202 and the optical fiber channel 203 are connected to the same end of the hollow cavity 201 to facilitate injection of liquid into the hollow cavity 201 .

[0054] The caliber of the injection channel 202 is smaller than the caliber of the hollow cavity 201 , and the injection channel 202 is eccentrically arranged relative to the hollow cavity 201 , that is, the central axis of the injection channel 202 and the central axis of the hollow cavity 201 are not on the same straight line.

[0055] When injecting the encapsulating liquid, the encapsulating container 200 is placed with the hollow cavity 201 and the liquid injection channel 202 in a vertical direction and the inlet of the liquid injection channel 202 facing upward. The encapsulating liquid is dripped into the liquid injection channel 203 in a vertical direction using a dropper, so that the encapsulating liquid reaches the hollow cavity 201 directly under the action of gravity.

[0056] The encapsulating liquid may be, but is not limited to, oil, water, or other liquids, as long as the encapsulating liquid does not cause too much damage to the sensing film 130 and can allow the sensing film 130 to maintain its basic performance.

[0057] Step 500: Seal the injection channel 202.

[0058] In step 500 , the injection channel 202 is sealed to prevent the encapsulation liquid in the hollow cavity 201 from leaking outward from the injection channel 202 .

[0059] The injection channel 202 can be sealed by, but is not limited to, a sealer 300. The sealer 300 includes a sealing portion 301 and a limiting portion 302 connected in the axial direction. The diameter of the limiting portion 302 is larger than the diameter of the sealing portion 301, so that the sealer 300 forms a stepped structure with a two-stage cylinder; the diameter of the sealing portion 301 is adapted to the caliber of the injection channel 202, so that the sealing portion 301 of the sealer 300 can enter the injection channel 202. When the sealing portion 301 enters the injection channel 202 to a predetermined depth, the limiting portion 302 of the sealer 300 abuts against the outer surface of the packaging container 200, thereby limiting the sealing portion 301 from further entering the injection channel 202.

[0060] In this embodiment, a screw-on seal is adopted between the sealer 300 and the packaging container 200. A sealing external thread is provided on the outer side of the sealing portion 301 of the sealer 300, and a sealing internal thread is provided on the inner side of the liquid injection channel 202 of the packaging container 200. The sealing external thread and the sealing thread cooperate with each other and are screwed together. An inner hexagonal groove is provided on the end surface of the limiting portion 302 facing away from the sealing portion 301 to facilitate the use of a hexagonal screwdriver to screw the sealer 300, thereby screwing the sealer 300 to the packaging container 200.

[0061] This liquid sealing method seals the FP interferometer on the FP fiber optic sensor 100 in the encapsulating liquid. Compared to the prior art method of directly exposing the FP interferometer to the outside air, because the refractive index of the encapsulating liquid is greater than that of air, the scattering angle of light becomes larger when it propagates to the interface between the sensing film 130 and the encapsulating liquid, and the amount of light scattered into the encapsulating liquid increases, while the amount of light reflected back into the FP fiber optic sensor 100 decreases. Therefore, interference with the interfering light signal is reduced, the nonlinearity of the FP fiber optic sensor 100 is reduced, and measurement errors are effectively eliminated.

[0062] Example 2

[0063] As an optimization solution of embodiment 1, in this embodiment, if Figure 5 As shown, the packaging container 200 is composed of a channel portion 210, a cavity portion 220, and a sealing gasket 230 located between the channel portion 210 and the cavity portion 220. The injection channel 202 and the optical fiber channel 203 are arranged in the channel portion 210, and the hollow cavity 201 is arranged in the cavity portion 220. When the channel portion 210 and the cavity portion 220 are connected together, the injection channel 202 and the optical fiber channel 203 are respectively connected to the hollow cavity 201, and the sealing gasket 230 is sandwiched between the channel portion 210 and the cavity portion 220.

[0064] The liquid sealing method further includes the following steps before step 200:

[0065] Step 100: Assemble the channel part 210, the cavity part 220 and the sealing gasket 230 together so that the injection channel 202 and the optical fiber channel 203 in the channel part 210 are respectively connected to the hollow cavity 201 in the cavity part 220, and the sealing gasket 230 is clamped between the channel part 210 and the cavity part 220.

[0066] Specifically, such as Figure 6 and 7 As shown, the channel portion 210 includes a first end portion 211 and a first connecting portion 212, the first end portion 211 and the first connecting portion 212 are connected in the axial direction, and the injection channel 202 and the optical fiber channel 203 are arranged in the first end portion 211; the cavity portion 220 includes a second end portion 221 and a second connecting portion 222, the second end portion 221 and the second connecting portion 222 are connected in the axial direction, and the hollow cavity 201 is arranged in the second connecting portion 222; the first connecting portion 212 and the second connecting portion 222 are relatively matched and connected.

[0067] The hollow cavity 201 is centrally arranged in the cavity part 220, that is, the central axis of the hollow cavity 201 coincides with the central axis of the cavity part 220; the injection channel 202 and the optical fiber channel 203 are both eccentrically arranged in the channel part 210, that is, the central axes of the injection channel 202 and the optical fiber channel 203 do not coincide with the central axis of the channel part 210; after the channel part 210 and the cavity part 220 are connected together, the end face of the second connecting part 222 of the cavity part 220 partially shields the injection channel 202, so that the connecting diameter between the injection channel 202 and the hollow cavity 201 is smaller than the diameter of the injection channel 202.

[0068] The first connecting portion 212 includes a connecting channel 213 and a first connecting wall 214 surrounding the connecting channel 213. One end of the connecting channel 213 is connected to the injection channel 202 and the optical fiber channel 203, and the other end is for the second connecting portion 222 to extend into. One end of the first connecting wall 214 is connected to the first end portion 211, and the other end is opposite to the second connecting portion 222; the second connecting portion 222 includes a support wall 223 and a second connecting wall 224. One end of the support wall 223 is connected to the second end portion 221, and the other end is connected to the second connecting wall 224. The other end of the second connecting wall 224 facing away from the support wall 223 is opposite to the first connecting portion 212; the support wall 223 is connected to the second end portion 221, and the other end is connected to the second connecting wall 224. The other end of the second connecting wall 224 facing away from the support wall 223 is opposite to the first connecting portion 212. The platform wall 223 and the second connecting wall 224 both surround the outside of the hollow cavity 201, and the thickness of the support platform wall 223 is greater than the thickness of the second connecting wall 224, so that a step structure with a secondary ring wall is formed on the outer surface of the second connecting part 222; the outer diameter of the second connecting wall 224 is matched with the inner diameter of the first connecting wall 214, so that the second connecting wall 224 can extend into the connecting channel 213 and then connect with the first connecting wall 214; when the second connecting wall 224 extends into the connecting channel 213, the support platform wall 223 faces one side end face of the first connecting wall 214, and together with the one side end face of the first connecting wall 214 facing the support platform wall 223, clamps the sealing gasket 230.

[0069] The outer diameter of the support platform wall 223 is greater than the outer diameter of the second connecting wall 224 , and the inner diameter of the support platform wall 223 is equal to the inner diameter of the second connecting wall 224 .

[0070] In this embodiment, the channel portion 210 and the cavity portion 220 are connected by a screw connection, and a screw-on internal thread is provided on the inner side surface of the first connecting wall 214, and a screw-on external thread is provided on the outer side surface of the second connecting wall 224; the screw-on external thread and the screw-on internal thread are screwed together; the outer sides of the channel portion 210 and the cavity portion 220 are provided with multiple straight grooves extending along the axial direction to increase the gripping friction during screwing.

[0071] In step 100 of the packaging method, the steps of assembling the channel portion 210, the cavity portion 220 and the sealing gasket 230 are as follows:

[0072] Step 101: stacking the sealing gasket 230 on the end surface of the support platform wall 223 of the cavity portion 210 facing the first connecting wall 214;

[0073] Step 102: Extend the second connecting wall 224 of the cavity part 220 into the connecting channel 213 of the channel part 210, and connect it with the first connecting wall 214 of the channel part 210 until the end face of one side of the support platform wall 223 faces the first connecting wall 214, and clamps the sealing gasket 30 together with the end face of one side of the first connecting wall 214 facing the support platform wall 223.

[0074] Example 3

[0075] As an optimization solution of Example 1 or Example 2, in this embodiment, the FP optical fiber sensor is an electric field or magnetic field sensor, and the packaging container 200 and the sealer 300 are both made of non-electromagnetic shielding materials, such as plastic, to reduce the loss of the external electric field or magnetic field transmitted to the FP interferometer of the FP optical fiber sensor.

[0076] Example 4

[0077] As another optimization solution of Example 1 or Example 2, in this embodiment, the FP optical fiber sensor is a pressure sensor or a vibration sensor, and the thickness of the second end portion 221 should be as thin as possible to reduce the loss during pressure or vibration transmission. Preferably, the second end portion 221 of the packaging container 200 is a conductive film.

[0078] The conductive film includes a fixed area and a conductive area. The fixed area surrounds the periphery of the conductive area and is fixedly connected to the end surface of the second connecting portion 222 facing away from the first connecting portion 212. One end of the conductive area is exposed in the hollow cavity 201, and the other end is exposed to the external environment, so as to transmit external pressure or vibration to the encapsulation liquid in the hollow cavity 201, and then transmit it to the FP interferometer of the FP optical fiber sensor through the encapsulation liquid.

[0079] Example 5

[0080] As another optimization solution of Example 1 or Example 2, in this embodiment, the FP optical fiber sensor is a temperature sensor. The packaging container 200 and the sealer 300 are both entirely made of a high thermal conductivity material, such as stainless steel, to reduce the loss of external heat conducted to the FP interferometer of the FP optical fiber sensor. The packaging liquid can also be a liquid with a low specific heat capacity to quickly heat up and improve the sensing speed.

[0081] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the embodiments of the present invention rather than to limit them. Although the embodiments of the present invention are described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solutions of the embodiments of the present invention can still be modified or replaced by equivalents, and these modifications or equivalent replacements cannot cause the modified technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A liquid sealing method for an FP optical fiber sensor, characterized in that: The steps include: Step 100: The packaging container is composed of a channel portion, a cavity portion, and a sealing gasket. The channel portion, the cavity portion, and the sealing gasket are assembled together so that the injection channel and the optical fiber channel in the channel portion are respectively connected to the hollow cavity in the cavity portion, and the sealing gasket is sandwiched between the channel portion and the cavity portion. Step 200: inserting the FP interferometer on the FP fiber optic sensor into the hollow cavity of the packaging container through the fiber optic channel; Step 300: Sealing and fixing the FP optical fiber sensor to the optical fiber channel; Step 400: injecting encapsulation liquid into the hollow cavity of the encapsulation container through the liquid injection channel, so that the encapsulation liquid at least immerses the FP interferometer on the FP optical fiber sensor; Step 500: sealing the injection channel; In step 200, the packaging container is placed with the hollow cavity and the optical fiber channel in a vertical direction and the entrance of the optical fiber channel facing upward, and the FP optical fiber sensor is vertically inserted into the optical fiber channel with the FP interferometer facing downward, so that the FP interferometer on the FP optical fiber sensor directly reaches the hollow cavity.

2. The liquid sealing method for an FP optical fiber sensor according to claim 1, wherein: In step 300, the FP optical fiber sensor and the optical fiber channel are sealed and fixed by using sealant.

3. The liquid sealing method for an FP optical fiber sensor according to claim 1, wherein: In step 400, the packaging container is placed with the hollow cavity and the liquid injection channel in a vertical direction and the inlet of the liquid injection channel facing upward, and the packaging liquid is dripped into the liquid injection channel in a vertical direction using a dropper so that the packaging liquid reaches the hollow cavity directly under the action of gravity.

4. The liquid sealing method for an FP optical fiber sensor according to claim 1, wherein: In step 500, the injection channel is sealed using a sealer.

5. The liquid sealing method for an FP optical fiber sensor according to claim 4, wherein: The sealer includes a sealing portion and a limiting portion connected in the axial direction. The diameter of the limiting portion is larger than the diameter of the sealing portion, so that the sealer forms a stepped structure with a two-stage cylinder; the diameter of the sealing portion is adapted to the caliber of the injection channel, so that the sealing portion of the sealer can extend into the injection channel. When the sealing portion extends into the injection channel to a predetermined depth, the limiting portion of the sealer abuts against the outer surface of the packaging container, thereby limiting the sealing portion from further extending into the injection channel.

6. The liquid sealing method for an FP optical fiber sensor according to claim 1, wherein: The channel portion includes a first end portion and a first connecting portion, the first end portion and the first connecting portion are connected along the axial direction, and the injection channel and the optical fiber channel are arranged in the first end portion; the cavity portion includes a second end portion and a second connecting portion, the second end portion and the second connecting portion are connected along the axial direction, and the hollow cavity is arranged in the second connecting portion; the first connecting portion and the second connecting portion are relatively matched and connected.

7. The liquid sealing method for an FP optical fiber sensor according to claim 6, wherein:

18. The foldable connector of claim 17, wherein the second connector has a first end configured to extend from a first end of the second connector and a second end of the second connector. The foldable connector of claim 17, wherein the second end of the second connector is configured to extend from a first end of the second connector and a second end of the second connector. The foldable connector of the second connector is constructed so that the foldable connector can extend from a first end of the second connector to a second end of the second connector.

8. The liquid sealing method for an FP optical fiber sensor according to claim 7, wherein: In step 100, the steps of assembling the channel portion, the cavity portion and the sealing gasket are as follows: Step 101: stacking the sealing gasket on the end surface of the support wall of the cavity portion facing the first connecting wall; Step 102: Extend the second connecting wall of the cavity part into the connecting channel of the channel part, and connect it with the second connecting wall of the channel part until the end face of one side of the support platform wall faces the first connecting wall, and clamp the sealing gasket together with the end face of one side of the first connecting wall facing the support platform wall.

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