CN217331450U - Microbubble probe and pressure sensing system - Google Patents

Abstract

The utility model discloses a microbubble probe, comprising an optical fiber, a microbubble cavity and a pressure probe, the microbubble cavity is arranged on one end face of the optical fiber, and the pressure probe is arranged on the microbubble cavity On the outer side of the microbubble cavity; the cavity wall of the microbubble cavity has an end region and a surrounding region, the surrounding region can be deformed by force, and its plane is perpendicular to the axial direction of the optical fiber; the pressure probe is located at the end In the region, its axial direction is parallel to the axial direction of the optical fiber; a Fabry-Perot cavity is formed between the end face of the optical fiber facing the microbubble cavity and the end of the microbubble cavity. The microbubble probe can improve the upper limit of pressure measurement, and at the same time realize the pressure measurement of a single point on the measured object. The utility model also discloses a pressure sensing system, which comprises the above-mentioned microbubble probe.

Description

A microbubble probe and pressure sensing system

technical field

The utility model relates to sensing technology, in particular to a microbubble probe and a pressure sensing system.

Background technique

In microsystems, microfluidic systems, and similar systems, it is often necessary to sense the forces exerted on tiny components. When fabricating, processing, and assembling these systems, real-time mechanical information can help operators perform tasks in a reasonable manner. . Most of the mechanical sensors used in the past are based on micro-electromechanical systems, namely MEMS Force Sensors. After decades of development, MEMS sensors have been relatively mature and have been widely used in engineering. However, their large size and electrical nature limit their applications, making them unable to operate in microscale and various liquids. Environment, high temperature and ultra-low temperature environment, strong corrosive environment, and will be subject to electromagnetic interference.

Due to the material and optical properties of the optical fiber itself, the optical fiber sensor is immune to electromagnetic interference, and can withstand high and ultra-low temperatures, and can work stably in various liquid and gas environments. Optical fiber-based mechanical sensors have become a new solution for mechanical measurement.

The Chinese patent with the patent number CN201410173102.3 discloses a pressure sensor based on an optical fiber FP interferometer, including an optical fiber; the end of the optical fiber has an FP cavity; the thickness of the bubble wall of the FP cavity close to the end of the optical fiber It is thinnest at the position where the fiber core passes through, and gradually thickens from this position toward its periphery. As shown in Figure 1-3, the bubble wall near the end of the optical fiber in the FP cavity 801 of the pressure sensor (the area shown by the dotted line in Figure 1) is the pressure sensitive area of the pressure sensor. The end where the cavity 801 is located is placed in the environment of the pressure to be detected, and the other end is connected to a spectrometer and other spectral analysis instruments. When the end of the optical fiber where the FP cavity 801 is located is in a pressure environment, the pressure exerted by the environment on the FP cavity 801 is shown by the arrow in FIG. 2 . As shown in FIG. 3 , L is the cavity length of the FP cavity 801 along the axial direction of the optical fiber when the FP cavity 801 is not subjected to ambient pressure. When the FP cavity 801 is subjected to an ambient pressure P, the pressure sensitive area of the FP cavity 801 will be concave inward due to the ambient pressure, thereby causing the cavity length of the FP cavity 801 along the fiber axis to be shortened by a corresponding length ΔL. Through experiments, it is found that there is a corresponding relationship between ΔL and P, and there is also a corresponding relationship between the cavity length of the FP cavity 801 along the fiber axis and the free spectral width of the laser spectrum reflected by the FP cavity 801. The free spectral width of the laser spectrum reflected back by the FP cavity 801 can detect the cavity length of the FP cavity 801 along the optical fiber axis, thereby detecting ΔL, and then detecting the ambient pressure P.

The thinnest part of the bubble wall of the FP cavity of the above pressure sensor is not only the pressure sensitive area of the pressure sensor, which is used to generate deformation under the ambient pressure, but also the pressure bearing area of the pressure sensor, which is used to directly bear the effect of the environmental pressure. Because the bubble wall at the thinnest part is too thin and is directly stressed, if the environmental pressure is too high, it will directly break and rupture, so the pressure sensor cannot be used to measure the large environmental pressure; at the same time, the pressure sensor has The pressure sensitive area is a deformable spherical surface, which can only be in surface contact with the measured object, but not in point contact, so it can only be used for the measurement of a wide range of environmental pressures such as air pressure and hydraulic pressure, but cannot be used for contact pressing. Single point pressure measurement of generated pressure, displacement, target Young's modulus, etc.

Utility model content

In order to solve the above-mentioned deficiencies of the prior art, the present invention provides a microbubble probe, which can increase the upper limit of pressure measurement and simultaneously realize the pressure measurement of a single point on the measured object.

The utility model also provides a pressure sensing system, which includes the above-mentioned microbubble probe.

The technical problem to be solved by this utility model is realized through the following technical solutions:

A microbubble probe comprising an optical fiber, a microbubble cavity and a pressure probe, the microbubble cavity is arranged on one end face of the optical fiber, the pressure probe is arranged on the outer side of the microbubble cavity, and the A Fabry-Perot cavity is formed between the end face of the optical fiber facing the microbubble cavity and the end of the microbubble cavity; the cavity wall of the microbubble cavity has an end region and a surrounding region, and the surrounding region The force can be deformed, and its plane is perpendicular to the axial direction of the optical fiber; the pressure probe is located on the end region, and its axial direction is parallel to the axial direction of the optical fiber.

Further, the wall thickness of the surrounding area is smaller than the wall thickness of the end area.

Further, the cavity wall of the microbubble cavity has the smallest wall thickness at the surrounding area.

Further, the optical fiber includes a core and a cladding.

Further, the cladding layer is connected with the cavity wall of the microbubble cavity, and the fiber core is connected with the air cavity of the microbubble cavity.

Further, a vertebral portion of a quartz tube is also included, and the vertebral portion of the quartz tube is connected between the optical fiber and the microbubble cavity.

Further, the optical fiber is a single-mode optical fiber or a multi-mode optical fiber.

A pressure sensing system, comprising a broadband light source, a 3dB coupler, a spectrometer, and the above-mentioned microbubble probe, wherein the broadband light source and the spectrometer are connected to the other end face of an optical fiber in the microbubble probe through the 3db coupler .

Further, a computing control device is also included, and the computing control device is connected in communication with the signal demodulation device.

Further, the computing control device is a personal computer

The utility model has the following beneficial effects: the microbubble probe separates the end region and the surrounding region on the microbubble cavity, the end region is directly in contact with the pressure, and translates along the pressure direction when being stressed, and the surrounding region Not in direct contact with the pressure, but deformed under the translational extrusion of the end region, thereby causing the cavity length of the microbubble cavity to change. Since the surrounding region is not in direct contact with the pressure, the end region will The pressure received is transmitted from the end of the microbubble cavity to the equatorial plane of the microbubble cavity, which is equivalent to increasing the working surface of the pressure, reducing the pressure on the surrounding area, and avoiding the surrounding area. The area is broken and ruptured, which increases the upper limit of pressure measurement; at the same time, the pressure, displacement, target Young's pressure generated by contact pressing can be realized by contacting a single point on the measured object through the additional pressure probe. Single point pressure measurement such as modulus.

Description of drawings

1 is a schematic structural diagram of an existing pressure sensor;

FIG. 2 is a schematic diagram of the FP cavity of the existing pressure sensor being subjected to environmental pressure;

FIG. 3 is a schematic diagram of the change of the cavity length along the axis of the optical fiber when the FP cavity of the existing pressure sensor is subjected to ambient pressure;

4 is a schematic structural diagram of a microbubble probe provided by the present invention;

5 is a schematic diagram of the force of the microbubble probe provided by the present invention;

6 is a schematic structural diagram of another microbubble probe provided by the present invention;

FIG. 7 is a schematic diagram of the principle of the pressure sensing system provided by the present invention.

Detailed ways

The present invention will be described in detail below with reference to the accompanying drawings and embodiments, examples of which are shown in the accompanying drawings, wherein the same or similar reference numerals represent the same or similar elements or elements with the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary, and are intended to be used to explain the present invention, but should not be construed as a limitation of the present invention.

In the description of the present invention, it should be understood that the terms "length", "width", "upper", "lower", "front", "rear", "left", "right", "vertical" , "horizontal", "top", "bottom", "inside", "outside" and other indications of orientation or positional relationship are based on the orientation or positional relationship shown in the accompanying drawings, only for the convenience of describing the present utility model and simplifying the description , rather than indicating or implying that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be construed as a limitation on the present invention.

In addition, the terms "first", "second" and "third" are used for descriptive purposes only, and should not be construed as indicating or implying relative importance or implying the number of indicated technical features. Thus, a feature defined as "first", "second", "third" may expressly or implicitly include one or more of that feature. In the description of the present invention, "plurality" means two or more, unless otherwise expressly and specifically defined.

In the present utility model, unless otherwise expressly specified and limited, terms such as "installation", "connection", "connection", "fixation", "arrangement" and the like should be understood in a broad sense, for example, it may be a fixed connection, or It can be a detachable connection or an integrated body; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, and it can also be the internal communication of two elements or the interaction of the two elements relation. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific situations.

Example 1

As shown in FIG. 4 , a microbubble probe includes an optical fiber 1, a microbubble cavity 2 is provided on one end surface of the optical fiber 1, and a pressure probe 23 is provided on the outer side of the microbubble cavity 2. The A Fabry-Perot cavity is formed between the end face of the optical fiber 1 facing the microbubble cavity 2 and the end of the microbubble cavity 2; the cavity wall of the microbubble cavity 2 has an end region 21 and a surrounding region 22 , the surrounding area 22 can be deformed by force, and its plane is perpendicular to the axial direction of the optical fiber 1; the pressure probe 23 is located on the end area 21, and its axial direction is parallel to the axial direction of the optical fiber 1 .

A Fabry-Perot cavity is formed between the end face of the optical fiber 1 of the microbubble probe facing the microbubble cavity 2 and the end of the microbubble cavity 2, and the optical signal incident into the optical fiber 1 is located at the end of the microbubble cavity 2. The end face of the optical fiber 1 facing the microbubble cavity 2 generates a first reflected light, and the end of the microbubble cavity 2 generates a second reflected light, and interference is formed between the first reflected light and the second reflected light , and its interference spectrum is related to the cavity length of the microbubble cavity 2. As shown in Figure 5, when the microbubble cavity 2 is deformed by force and the cavity length changes, the interference spectrum will drift, and the amount of drift is related to The variation of the cavity length of the microbubble cavity 2 is related to ΔL, and the variation of the cavity length of the microbubble cavity 2 is also related to the magnitude of the pressure F, so it can be calculated from the drift of the interference spectrum. The size of the pressure F that the microbubble cavity 2 is subjected to.

The microbubble probe separates the end region 21 and the surrounding region 22 on the microbubble cavity 2, the end region 21 is in direct contact with the pressure F, and translates in the direction of the pressure F when the pressure is applied, and the surrounding region 22 does not In direct contact with the pressure F, it is deformed under the translational extrusion of the end region 21, thereby causing the cavity length of the microbubble cavity 2 to change. Since the surrounding region 22 is not in direct contact with the pressure F, the The end area 21 transmits the pressure F from the end of the microbubble cavity 2 to the plane where the surrounding area 22 is located, which is equivalent to increasing the working surface of the pressure F and reducing the pressure F of the surrounding area 22. The pressure is small, which can prevent the surrounding area 22 from being broken and ruptured, and improve the upper limit of the measurement of the pressure F; at the same time, the additional pressure probe 23 is contacted with a single point on the object to be measured, and the contact force can be realized. Pressure measurement at a single point such as pressure F, displacement, target Young's modulus, etc.

Preferably, the surrounding area 22 surrounds the equatorial plane of the microbubble cavity 2 .

The cross section of the microbubble cavity 2 on the equatorial plane is the largest, and the surrounding area 22 is arranged on the equatorial plane of the microbubble cavity 2 to minimize the pressure on the surrounding area 22. As well as maximizing the upper measurement limit of the pressure F.

The end region 21 also undergoes a certain amount of deformation under force, or does not deform, depending on the wall thickness of the end region 21. The greater the wall thickness of the end region 21, the greater the amount of force deformation. Small; when the pressure probe 23 acts on the pressure, part of the pressure causes the deformation of the end region 21, and the remaining part is conducted to the surrounding region 22, causing the deformation of the surrounding region 22, the end The deformation amount of the region 21 is much smaller than the deformation amount of the surrounding region 22, so it can be ignored, and it is considered that the surrounding region 22 bears all the pressure.

The wall thickness of the surrounding area 22 is smaller than the wall thickness of the end area 21, so that when the pressure probe 23 is pressed by the object to be measured, the deformation of the end area 21 when the pressure is applied is as small as possible or not. It deforms and translates to the surrounding area 22 along the force direction, and the surrounding area 22 is deformed by the translational extrusion of the end area 21 .

Preferably, the wall thickness of the microbubble cavity 2 is the smallest at the surrounding area 22 .

The optical fiber 1 includes a core 11 and a cladding 12, the cladding 12 is clad on the outer peripheral wall of the core 11, and the core 11 and the cladding 12 have different refractive indices, So that the optical signal in the optical fiber 1 can be totally reflected at the interface between the core 11 and the cladding 12, and propagate forward in the core 11; the cladding 12 and the The cavity wall of the microbubble cavity 2 is connected, and the fiber core 11 is connected with the air cavity of the microbubble cavity 2, so that the optical signal in the fiber core 11 can be incident from the end face of the fiber core 11 to the air cavity. inside the microbubble cavity 2 .

The optical fiber 1 can be, but not limited to, a single-mode optical fiber or a multi-mode optical fiber.

Embodiment 2

As another specific implementation of the first embodiment, as shown in FIG. 6 , the microbubble probe of this embodiment further includes a quartz tube vertebra 3, and the quartz tube vertebra 3 is connected to the optical fiber 1 and the microbubble cavity between 2.

The tube wall of the vertebral portion 3 of the quartz tube is trumpet-shaped, the larger radial side is connected to the optical fiber 1, and the smaller radial side is connected to the microbubble cavity 2, and the optical fiber 1 The cladding 12 is connected to the cavity wall of the microbubble cavity 2 through the tube wall of the quartz tube vertebra 3, and the core 11 of the optical fiber 1 is connected to the Air cavity of microbubble cavity 2.

The tube wall of the quartz tube vertebra 3 is also larger than the cavity wall of the surrounding area 22, so that when the pressure F is measured, the quartz tube vertebra 3 does not deform, or the deformation is as small as possible, which can be ignored.

Embodiment 3

As shown in FIG. 7 , a pressure sensing system includes a broadband light source, a 3dB coupler, a spectrometer, and the microbubble probe described in Embodiment 1 or Embodiment 2. The broadband light source and the spectrometer pass through the 3dB coupler. Connect to the other end face of the optical fiber 1 in the microbubble probe.

The broadband light source is used to emit light signals, the spectrometer is used to receive the light signals reflected from the optical fiber 1 of the microbubble probe, and the interference spectrum is obtained, and the 3db coupler is used to connect the broadband light source. The emitted optical signal is coupled into the optical fiber 1 of the microbubble probe, and the first reflected light and the second reflected light reflected back in the optical fiber 1 of the microbubble probe are coupled into the spectrometer.

When measuring the pressure F, the broadband light source first emits an optical signal into the optical fiber 1 of the microbubble probe, and the optical signal incident into the optical fiber 1 is at the end face of the optical fiber 1 facing the microbubble cavity 2 The first reflected light is generated on the microbubble cavity 2, and the second reflected light is generated at the end of the microbubble cavity 2. The first reflected light and the second reflected light form interference, and the spectrometer receives the reflected first reflected light. and the second reflected light to obtain the interference spectrum; contact and press the pressure probe 23 on the microbubble probe with multiple points on the standard object, causing the cavity length of the microbubble cavity 2 to change to varying degrees , obtain multiple interference spectra with different offsets, and calculate the relationship curve between the drift of the interference spectrum and the pressure F; connect the pressure probe 23 on the microbubble probe with the single Contact and press the point to obtain the interference spectrum of the measured object at this point. According to the drift of the interference spectrum at this point, and the relationship curve between the drift of the interference spectrum and the pressure F, finally calculate the measured object. The magnitude of the pressure F at this point.

The pressure sensing system further includes a computing control device, which is connected in communication with the broadband light source and the spectrometer, respectively, for controlling the broadband light source and the spectrometer, specifically controlling the opening of the broadband light source and the spectrometer. On and off, the interference spectrum obtained by the spectrometer is analyzed and calculated at the same time.

In this embodiment, the computing control device is a personal computer.

Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the embodiments of the present utility model rather than limit them. Although the embodiments of the present utility model have been described in detail with reference to the preferred Personnel should understand that the technical solutions of the embodiments of the present invention can still be modified or equivalently replaced, and these modifications or equivalent replacements cannot make the modified technical solutions depart from the scope of the technical solutions of the embodiments of the present invention.

Claims (10)

1. A microbubble probe, comprising an optical fiber and a microbubble cavity, the microbubble cavity is arranged on an end face of the optical fiber, and the end face of the optical fiber facing the microbubble cavity is connected to the end face of the microbubble cavity. A Fabry-Perot cavity is formed between the ends; it is characterized in that it also includes a pressure probe, the pressure probe is arranged on the outer side of the microbubble cavity; the cavity wall of the microbubble cavity has an end region and a surrounding area, the surrounding area can be deformed by force, and its plane is perpendicular to the axial direction of the optical fiber; the pressure probe is located on the end area, and its axial direction is parallel to the axial direction of the optical fiber. 2 . The microbubble probe of claim 1 , wherein a wall thickness of the surrounding region is smaller than a wall thickness of the end region. 3 . 3 . The microbubble probe according to claim 2 , wherein the cavity wall of the microbubble cavity has the smallest wall thickness at the surrounding area. 4 . 4. The microbubble probe of claim 1, wherein the optical fiber comprises a core and a cladding. 5 . The microbubble probe according to claim 4 , wherein the cladding layer is connected to the cavity wall of the microbubble cavity, and the fiber core is connected to the air cavity of the microbubble cavity. 6 . 6 . The microbubble probe according to claim 1 , further comprising a vertebral portion of a quartz tube connected between the optical fiber and the microbubble cavity. 7 . 7. The microbubble probe according to claim 1, wherein the optical fiber is a single-mode optical fiber or a multi-mode optical fiber. 8. A pressure sensing system, characterized by comprising a broadband light source, a 3dB coupler, a spectrometer and the microbubble probe according to any one of claims 1-7, wherein the broadband light source and the spectrometer are coupled through the 3db The connector is connected to the other end face of the optical fiber in the microbubble probe. 9 . The pressure sensing system according to claim 8 , further comprising a calculation control device, the calculation control device is respectively connected in communication with the broadband light source and the spectrometer. 10 . 10. The pressure sensing system according to claim 9, wherein the computing control device is a personal computer.

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