Sensing diaphragm based on optical fiber F-P cavity, sensor and application

Abstract

The invention relates to the technical field of optical fiber sensing, in particular to a sensing diaphragm based on an optical fiber F-P cavity, a sensor and application, the sensing diaphragm based on the optical fiber F-P cavity comprises a body, and a through vent hole is formed in the body. Through the arrangement, internal and external air pressure after the diaphragm is deformed can be balanced, errors caused by pressure difference are reduced, the sensitivity of an original sensing diaphragm is greatly improved within the range of high detection frequency, and measurement of weak signals is facilitated.

Description

Technical Field

[0001] The present invention relates to the field of optical fiber sensing technology, and in particular to a sensing diaphragm based on an optical fiber FP cavity, a sensor and applications. Background Art

[0002] Fiber optic FP cavity sensors have the advantages of small size and high sensitivity, and are widely used in various engineering fields, such as partial discharge of cables and ultrasonic underwater acoustic detection.

[0003] A general fiber optic FP cavity sensor includes a sensing diaphragm that can deform with changes in external variables. Therefore, by monitoring the offset of the interference light inside the FP cavity, the change in external parameters can be obtained, thereby measuring the ultrasonic signal.

[0004] However, when the sensing diaphragm deforms, existing fiber-optic FP cavity sensors are unable to balance the air pressure on both sides of the sensing diaphragm. This creates a pressure differential across the sensing diaphragm, which introduces errors and significantly reduces the sensor's detection sensitivity. Furthermore, increasing the natural frequency parameters of conventional sensing diaphragms inevitably leads to a significant reduction in mechanical sensitivity, reducing detection accuracy in high-frequency applications. Summary of the Invention

[0005] In order to solve the defects of the existing optical fiber FP cavity sensor that cannot balance the air pressure on both sides of the sensing diaphragm and the high frequency detection range will lead to reduced detection sensitivity, the present invention proposes a sensing diaphragm based on the optical fiber FP cavity, a sensor and its application.

[0006] The technical solution adopted by the present invention is a sensing diaphragm based on an optical fiber FP cavity, comprising a body, wherein a through vent hole is opened on the body.

[0007] Preferably, there are multiple ventilation holes, and the multiple ventilation holes are evenly arranged on the main body.

[0008] Preferably, the body is circular, and a plurality of the ventilation holes are evenly arranged along the circumference of the body.

[0009] Preferably, the body includes a first part arranged inside, and a second part arranged outside and connected to the first part, the vent hole is opened on the first part, and the second part is a circular ring.

[0010] Preferably, there are three vent holes.

[0011] Preferably, the first part includes three first sectors and three second sectors, the radius of the first sector is greater than the radius of the second sector; the three first sectors and the three second sectors are alternately connected along the circumference of the body, the arc edge of the first sector is connected to the second part, and the through hole surrounded by the first sector, the second sector and the second part is the vent.

[0012] The present invention also provides a sensor based on an optical fiber FP cavity, comprising the above-mentioned sensing membrane based on an optical fiber FP cavity.

[0013] Preferably, it further comprises a cavity, and the sensing membrane based on the optical fiber FP cavity is arranged on the end face of the cavity.

[0014] The present invention also proposes an application of the above-mentioned sensor based on the optical fiber FP cavity, wherein the sensor based on the optical fiber FP cavity is used for ultrasonic detection inside electrical equipment.

[0015] The present invention also proposes an application of the above-mentioned sensor based on the optical fiber FP cavity, where the sensor based on the optical fiber FP cavity is used for underwater sensing or environmental monitoring.

[0016] Compared with the prior art, the present invention has the following beneficial effects:

[0017] When an external signal acts on the sensing diaphragm, the sensing diaphragm will deform, and the interference light path within the sensing cavity where the sensing diaphragm is installed will shift, thereby achieving visual quantitative detection of external signals. The through-holes opened in the main body can balance the internal and external air pressure after the diaphragm is deformed, reducing the error caused by the pressure difference. This greatly improves the sensitivity of the original sensing diaphragm within the high detection frequency range, facilitates the measurement of weak signals, and solves the problem of low sensitivity of the sensing diaphragm at high frequencies. At the same time, the internal dimensional parameters of the sensing diaphragm can be adjusted, and the internal parameters of the sensing diaphragm can be changed according to different frequency detection requirements. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] The present invention is described in detail below with reference to the embodiments and accompanying drawings, in which:

[0019] Figure 1 It is a schematic diagram of the structure of the sensing diaphragm based on the optical fiber FP cavity;

[0020] Figure 2 This is the first-order natural frequency and displacement finite element simulation diagram of the sensing diaphragm based on the optical fiber FP cavity;

[0021] Figure 3 It is the deviation of the interference spectrum of the sensor based on the fiber FP cavity as the external variables change.

[0022] 10. First part; 11. First sector; 12. Second sector; 13. Ventilation hole;

[0023] 20. Part 2. DETAILED DESCRIPTION

[0024] To make the objectives, technical solutions, and advantages of the present invention more apparent, embodiments of the present invention will be described in further detail below with reference to the accompanying drawings. Examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar components or components having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are intended only to explain the present invention and are not to be construed as limiting the present invention.

[0025] According to the traditional formula for circular diaphragm sensitivity and frequency, the sensitivity of the diaphragm is proportional to its thickness and inversely proportional to its radius. However, since sensitivity is inversely proportional to thickness and directly proportional to radius, under certain parameters, the sensitivity and frequency generally change in opposite directions. That is, when the thickness and radius of the CD are changed to increase the mechanical sensitivity of the device, the sensor's detection frequency range is correspondingly reduced. This phenomenon limits the sensor's sensitivity improvement in the ultrasonic range. Therefore, the present invention proposes a sensing diaphragm based on a fiber optic FP cavity.

[0026] In one embodiment, Figure 1 As shown, a sensing diaphragm based on an optical fiber FP cavity includes a main body with a through vent hole 13. When an external signal acts on the sensing diaphragm, the sensing diaphragm will be deformed, and the interference light path in the sensing cavity in which the sensing diaphragm is provided will be offset, thereby realizing visual quantitative detection of the external signal. The through vent hole 13 provided on the main body can balance the internal and external air pressure after the diaphragm is deformed, reducing the error caused by the pressure difference, and realizing a great improvement in the sensitivity of the original sensing diaphragm within the range of high detection frequency, facilitating the measurement of weak signals, and solving the problem of low sensitivity of the sensing diaphragm at high frequency. It can be used to measure a variety of external variables, such as electrical signals, acoustic signals, pressure, etc., and has broad application prospects.

[0027] In one embodiment, a plurality of vent holes 13 are provided, and the plurality of vent holes 13 are evenly provided on the main body. Compared with a single vent hole 13, the evenly distributed plurality of vent holes 13 are more conducive to vacuum conduction and balancing the air pressure, thereby eliminating the interference factor of the air pressure difference inside the sensor, thereby improving the homogeneous performance of the detection.

[0028] In one embodiment, the body is circular, with a thickness of t, a center of the circular body of O, and a radius of r. o, multiple ventilation holes 13 are evenly opened along the circumference of the body. The body includes a first part 10 arranged inside, and a second part 20 arranged outside and connected to the first part 10. The ventilation holes 13 are opened on the first part 10. The second part 20 is a circular ring with a width of h. There are three ventilation holes 13. The first part 10 includes three first sectors 11 and three second sectors 12 with an angular arc of 60 degrees. The radius r of the first sector 11 is 60 degrees. m Greater than the radius r of the second sector 12 i The three first sectors 11 and the three second sectors 12 are alternately connected along the circumference of the body. The through hole surrounded by the first sector 11, the second sector 12 and the second part 20 is a vent 13, that is, the radius of the first sector 11, the arc edge of the second sector 12 and the inner edge of the second part 20 form a total of three vents 13.

[0029] The vent hole 13 has an angular arc equal to the angular arc of the second sector 12 and a radius equal to the radius r of the first sector 11. m The first sector minus the second sector 12.

[0030] The sensing diaphragm in this embodiment has the advantages of simple structure, easy production and manufacturing, high sensitivity, high frequency detection range, and resistance to electromagnetic interference. The sensing diaphragm uses three symmetrical vents 13 to balance the internal and external air pressure after the sensing diaphragm is deformed, thereby improving the mechanical sensitivity of the sensing diaphragm itself. The sensing diaphragm has stable performance, simple structure, easy manufacturing, tunable parameters, can achieve high-sensitivity signal detection and stabilize the natural frequency, so that weaker signals can be detected, the response speed is faster, and the results are more accurate. The sensing diaphragm in this embodiment not only improves the detection sensitivity of the sensor, but also meets the sensor's detection requirements for ultrasonic frequencies, and realizes tunability of sensitivity and frequency within a certain range.

[0031] In other embodiments, the material, thickness, and radius of the body, the number of vent holes 13, the width of the second portion 20, the number of first sectors 11 and second sectors 12, the angular arc, and the radius, etc. can also be set differently according to different sensing requirements to achieve tunable diaphragm and be suitable for various application scenarios. That is, the overall circular body of the sensing diaphragm remains unchanged, but the hollow shape (vent hole shape) inside it can be changed to adapt to the detection requirements of different frequencies. In other embodiments, the vent holes 13 can also be set to other structures.

[0032] The natural frequency and sensitivity of the sensor diaphragm are simulated using the finite element method, and the simulation diagram is as follows: Figure 2 As shown in the figure, the natural frequency selects the first-order natural frequency of the sensing diaphragm, and the maximum displacement of the center of the sensing diaphragm is the sensitivity of the sensing diaphragm. The interference spectrum generated by the sensor shifts with the change of external variables as shown in the figure. Figure 3By quantifying the offset, the change in the external signal can be quantified. The following table compares the parameters of the sensor diaphragm (ORC) with the vent 13 and the parameters of a conventional sensor diaphragm (CD) under the same conditions. It can be seen that the sensitivity of the sensor diaphragm with the vent 13 is significantly increased, while the natural frequency decreases slightly. In other words, the sensor diaphragm in this embodiment resolves the mutually exclusive relationship between sensitivity and detection frequency in sensors based on fiber optic FP cavities, and significantly increases the sensor's detection sensitivity while ensuring the ultrasonic detection frequency range.

[0033]

[0034] In one embodiment, a sensor based on an optical fiber FP cavity includes the optical fiber FP cavity-based sensing membrane in the above embodiment, which increases the sensitivity of the sensor itself and can quickly and accurately measure weak signals.

[0035] In one embodiment, the sensor based on the optical fiber FP cavity further includes a cavity, and a sensing diaphragm based on the optical fiber FP cavity is arranged on the end face of the cavity for sensing external signals and performing sensing. While improving the detection sensitivity, it minimizes the attenuation of the frequency detection range, thereby greatly expanding the application of the sensor.

[0036] In one embodiment, an application of the optical fiber FP cavity-based sensor in the above embodiment is used for ultrasonic detection inside electrical equipment to detect partial discharge.

[0037] In one embodiment, an application of the fiber optic FP cavity-based sensor in the above embodiment is used for underwater sensing or environmental monitoring.

[0038] In this specification, the use of terms such as "Embodiment 1," "this embodiment," and "in one embodiment" indicates that the specific features, structures, materials, or characteristics described in conjunction with that embodiment or example are included in the invention or at least one embodiment or example of the invention. In this specification, schematic representations of the above terms do not necessarily refer to the same embodiment or example; furthermore, the specific features, structures, materials, or characteristics described may be appropriately combined in any one or more embodiments or examples.

[0039] In the description of this specification, the terms "connect," "install," "fix," "dispose," and "have" are to be understood in a broad sense. For example, "connect" can mean a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, or it can be internal communication between two components. Those skilled in the art will understand the specific meanings of the above terms in this application based on specific circumstances.

[0040] In the description of this specification, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations. Moreover, the terms "comprises", "comprising" or any other variations thereof are intended to cover non-exclusive inclusion, so that a process, method, article or apparatus comprising a series of elements includes not only those elements, but also other elements not explicitly listed, or elements inherent to such process, method, article or apparatus. In the absence of further limitations, an element defined by the phrase "comprising a ..." does not exclude the presence of additional identical elements in the process, method, article or apparatus comprising the element.

[0041] The above description of the embodiments is to facilitate ordinary technicians in this technical field to understand and apply the technology of this case. People familiar with the technology in this field can obviously make various modifications to these examples easily and apply the general principles described here to other embodiments without having to go through creative work. Therefore, this case is not limited to the above embodiments. Modifications to the following situations should all be within the scope of protection of this case: ① A new technical solution implemented based on the technical solution of the present invention and combined with existing common knowledge, the technical effect produced by the new technical solution does not exceed the technical effect of the present invention; ② The equivalent replacement of some features of the technical solution of the present invention with the known technology, the technical effect produced is the same as the technical effect of the present invention; ③ The technical solution of the present invention is expandable, and the substantive content of the expanded technical solution does not exceed the technical solution of the present invention; ④ The equivalent transformation made by the content of the description and drawings of the present invention is directly or indirectly applied to other related technical fields.

Claims

1. A sensing diaphragm based on an optical fiber FP cavity, comprising a body, characterized in that: The main body is provided with a through vent hole.

2. The sensing diaphragm based on the optical fiber FP cavity according to claim 1, characterized in that: There are multiple vent holes, and the multiple vent holes are evenly arranged on the main body.

3. The sensing diaphragm based on the optical fiber FP cavity according to claim 2, characterized in that: The main body is circular, and a plurality of ventilation holes are evenly arranged along the circumference of the main body.

4. The sensing diaphragm based on the optical fiber FP cavity according to claim 3, characterized in that: The body includes a first portion disposed internally and a second portion disposed externally and connected to the first portion. The vent hole is provided on the first portion, and the second portion is a circular ring.

5. The sensing diaphragm based on the optical fiber FP cavity according to claim 4, characterized in that: There are three vent holes.

6. The sensing diaphragm based on the optical fiber FP cavity according to claim 5, characterized in that: The first part includes three first sectors and three second sectors, and the radius of the first sector is greater than the radius of the second sector; the three first sectors and the three second sectors are alternately connected along the circumference of the main body, the arc edge of the first sector is connected to the second part, and the through hole surrounded by the first sector, the second sector and the second part is the ventilation hole.

7. A sensor based on an optical fiber FP cavity, characterized in that: The invention comprises a sensing membrane based on an optical fiber FP cavity according to any one of claims 1 to 6.

8. The sensor based on optical fiber FP cavity according to claim 7, characterized in that: It also includes a cavity, and the sensing membrane based on the optical fiber FP cavity is arranged on the end surface of the cavity.

9. An application of a sensor based on an optical fiber FP cavity according to claim 7 or 8, characterized in that: The sensor based on the optical fiber FP cavity is used for ultrasonic detection inside electrical equipment.

10. An application of a sensor based on an optical fiber FP cavity according to claim 7 or 8, characterized in that: The sensor based on the optical fiber FP cavity is used for underwater sensing or environmental monitoring.

Images