CN112326077B - Micro contact force optical fiber sensing probe based on polymer hollow microtube and preparation method thereof - Google Patents

Abstract

The invention discloses a micro-contact force optical fiber sensing probe based on a polymer hollow microtube, which comprises a polymer hollow microtube and a single-mode optical fiber, and the outer periphery of the polymer hollow microtube is connected with the end face of the single-mode optical fiber. The light emitted from the single-mode fiber of the probe forms Fabry-Perot interference in the polymer hollow microtubes. When a micro-contact force acts on the polymer hollow microtubes, the polymer hollow microtubes are deformed, thereby modulating the interference light signal. , through the interference fringe wavelength demodulation of the reflection spectrum of the single-mode fiber, the ultra-sensitive micro-contact force sensing detection can be realized. The preparation operation of the polymer hollow microtube is simple, the preparation efficiency is high, the preparation cost is low, the mass production is easy, and the precise control of the size of the polymer hollow microtube can be realized.

Description

Micro-contact force optical fiber sensing probe based on polymer hollow microtubes and preparation method thereof

technical field

The invention relates to the technical field of optical fiber sensing, in particular to a micro-contact force optical fiber sensing probe based on a polymer hollow microtube, and a preparation method of the polymer hollow microtube.

Background technique

Contact force refers to the stress generated in the contact area and its vicinity when two contact objects are pressed against each other. The study of tiny contact force helps to achieve fine control. Micro-contact force sensors are widely used in biomedicine, material chemistry and other fields, and effectively help these disciplines to achieve innovation and progress. For example, in minimally invasive surgery, the micro-contact force sensor can sense biological tissue information, process and analyze it and transmit it to the doctor, so that the doctor can obtain the state of the real biological tissue and use it to determine whether the biological tissue is diseased; it can also effectively Optimize the surgical plan and improve the safety of the surgery.

Optical fiber sensing technology uses optical fiber as the medium for signal modulation and propagation, and senses and detects various information in the living and production environment through the optical fiber sensing system. The application field is broad, and it has been paid great attention when it came out.

In the prior art, the contact force optical fiber sensing probe is mainly based on fiber Bragg gratings. For example, the patent application 201880049665.8 uses the information of the center wavelength of the Bragg grating emission spectrum to measure the contact force. This type of sensing probe is based on quartz material. Due to the low Young's modulus of the quartz material, the sensing sensitivity is low, and it cannot accurately measure the tiny contact force. The polymer material has a higher Young's modulus, is easier to deform under the action of a small contact force, and has good resilience, which is more suitable for application in the optical fiber micro-contact force probe, which greatly improves the sensitivity of the probe.

In addition, the current preparation of polymer microstructures is mainly based on femtosecond laser two-photon polymerization technology. For example, patent application 201410375257.5 uses a high-power focused femtosecond laser to perform three-dimensional point-by-point scanning of unpolymerized UV-curable adhesives. The equipment cost is high, and the preparation It is inefficient and difficult to carry out mass production and industrialization promotion.

SUMMARY OF THE INVENTION

In order to solve the technical problems existing in the background art, the present invention provides a micro-contact force optical fiber sensing probe based on polymer hollow microtubes, and a preparation method of the polymer hollow microtubes.

The invention provides a micro-contact force optical fiber sensing probe of a polymer hollow microtube, which includes a polymer hollow microtube and a single-mode optical fiber.

Preferably, the outer periphery of the polymer hollow microtube and the end face of the core of the single-mode optical fiber are connected by ultraviolet curing glue.

Preferably, the central axis of the polymer hollow microtube intersects perpendicularly with the central axis of the single-mode optical fiber core; preferably, the central axis of the polymer hollow microtube is parallel to the core end face of the single-mode optical fiber.

Preferably, the polymer hollow microtubes are made of UV-curable glue; preferably, the model of the UV-curable glue is NOA65.

Preferably, the polymer hollow microtubes have an inner diameter of 80-100 μm, an outer diameter of 130-150 μm, and a length of 130-150 μm.

The present invention proposes a preparation method of polymer hollow microtubes, comprising:

S1, drop UV-curable adhesive on the surface of the substrate, and form a UV-curable adhesive film by spin coating;

S2, set up a multi-mode fiber and an ultraviolet laser, the laser generated by the ultraviolet laser is focused and irradiated to the end face of the incident end of the multi-mode fiber, and the output end of the multi-mode fiber is controlled to emit a ring laser beam by adjusting the incident angle of the laser;

S3, insert the exit end of the multi-mode optical fiber into the UV-curable adhesive film vertically and keep a preset distance from the substrate, open the laser shutter, expose the UV-curable adhesive film with a ring laser beam, close the laser shutter, and remove the multi-mode optical fiber;

S4, cleaning and separation, the exposed UV-curable glue on the surface of the substrate forms polymer hollow microtubes.

Preferably, in S1, the model of the UV-curable adhesive is NOA65; preferably, the thickness of the UV-curable adhesive film is 150-200 μm.

Preferably, in S2, the length of the multimode fiber is 1-3 m, and the core diameter is 100-105 μm.

Preferably, in S2, the wavelength of the laser generated by the ultraviolet laser is 385-405 nm, and the spot size is 4-6 mm; preferably, the laser generated by the ultraviolet laser is focused by a lens; preferably, the magnification of the lens is 40, and the numerical value of the lens The aperture is 0.65.

Preferably, S4 specifically includes: cleaning the UV-curable adhesive film with a developing solution, removing the unexposed UV-curable adhesive on the surface of the substrate, and forming the polymer hollow microtubes from the exposed UV-curable adhesive; Microtubules are isolated from the substrate.

The invention proposes a micro-contact force optical fiber sensing probe based on a polymer hollow micro-tube. The single-mode optical fiber of the probe forms Fabry-Perot interference in the polymer hollow micro-tube. When a micro-contact force acts on the polymerization On the material hollow microtube, the polymer hollow microtube is deformed, thereby modulating the interference light signal. By demodulating the interference fringe wavelength of the single-mode fiber reflection spectrum, ultra-sensitive micro-contact force sensing detection can be realized. In addition, the present invention also proposes a method for preparing polymer hollow microtubes that is fast, efficient and can be mass-produced. precise control.

Description of drawings

FIG. 1 is a schematic structural diagram of a micro-contact force optical fiber sensing probe based on a polymer hollow microtube according to an embodiment of the present invention.

FIG. 2 is a schematic diagram of the assembly process of the sensing probe in FIG. 1 .

FIG. 3 is a schematic diagram of a device for preparing a polymer hollow microtube according to an embodiment of the present invention.

Detailed ways

As shown in Figures 1-2, Figure 1 is a schematic structural diagram of a micro-contact force optical fiber sensing probe based on polymer hollow microtubes proposed in an embodiment of the present invention, and Figure 2 is a schematic diagram of the assembly process of the sensing probe in Figure 1 .

Referring to FIG. 1, a micro-contact force optical fiber sensing probe based on a polymer hollow microtube cable proposed by the present invention includes a polymer hollow microtube 1 and a single-mode optical fiber 2, and the outer periphery of the polymer hollow microtube 1 is cured by ultraviolet light. The glue 3 is connected to the end face of the core of the single-mode optical fiber 2 .

Referring to FIG. 2 , drop the UV-curable glue 3 on the core end face of the single-mode optical fiber 2, and then place the polymer hollow microtube 1 on the core end face of the single-mode optical fiber 2. 1 is connected to the core end face of the single-mode fiber 2 to form a micro-contact force fiber sensing probe. Among them, the model of UV curing adhesive can choose NOA65. During the setting process, the central axis of the polymer hollow microtube 1 perpendicularly intersects with the central axis of the single-mode optical fiber 2 , and the central axis of the polymer hollow microtube 1 is parallel to the end face of the single-mode optical fiber 2 .

In the above embodiment, the polymer hollow microtube 1 is made of UV-curable glue, and the model of the UV-curable glue can be selected as NOA65.

In the specific setting process, the inner diameter of the polymer hollow microtube 1 is 80-100 μm, the outer diameter is 130-150 μm, and the height is 130-150 μm. When the size of the polymer hollow microtube 1 is too large, the quality of the interference spectrum is affected, which is not conducive to the demodulation of the spectrum signal. When the size of the polymer hollow microtube 1 is too small, it is not conducive to the integration of the polymer hollow microtube 1 and the single-mode optical fiber 2 . Therefore, it is very suitable that the size of the polymer hollow microtube 1 is slightly larger than the diameter of the single-mode optical fiber 2 .

When the above probe is used, the probe is connected to a wide-spectrum light source and a spectrometer using a fiber optic circulator. The light emitted from the single-mode fiber of the probe is reflected by the two walls of the polymer hollow microtube 1 and returns to the single-mode fiber. 2, Fabry-Perot interference is formed, and distinct interference fringes can be observed in the reflection spectrum recorded by the spectrometer. When an axial micro-contact force is applied to the polymer hollow microtubes 1 of the probe, the polymer hollow microtubes 1 are deformed, and the interference of the reflected light signals is modulated with each other, and the interference fringes in the reflected spectrum are moved. Demodulation of the center wavelength shift of the interference fringes can realize ultra-sensitive detection of micro-contact force.

The embodiment of the present invention also proposes a preparation method of a polymer hollow microtube, comprising:

S1, select a clean glass slide 13 as the base, drop a drop of UV-curable glue in the center of the glass slide 13, and form a UV-curable adhesive film 14 on the glass slide through spin coating; The thickness is 150-200μm.

S2, set up multimode fiber and UV laser.

Select a multimode fiber 8 with a length of 1-3 m and a core diameter of 100-105 μm. If the length of the multimode fiber is too long, it will increase the loss of ultraviolet light, and if it is too short, the multimode fiber will be greatly bent when multiple fiber clamps fix the multimode fiber, which will increase the loss of ultraviolet light.

Cut both ends of the multimode optical fiber 8 flat, the incident end of the multimode optical fiber 8 is fixed horizontally with an optical fiber clamp, and the outgoing end of the multimode optical fiber is fixed with an optical fiber clamp 9 . The lens 7 is fixed on the multi-axis adjustment platform 12, and the laser light 5 generated by the ultraviolet laser is focused and irradiated to the end face of the incident end of the optical fiber through the shutter 6 and the lens 7. By adjusting the multi-axis adjustment platform 12, the focal position and beam of the laser light after passing through the lens 7 can be changed. angle. The laser wavelength generated by the ultraviolet laser is 385-405nm, and the spot size is 4-6mm; the laser generated by the ultraviolet laser is focused, the lens magnification is 40, and the numerical aperture is 0.65.

Under different incident angle conditions, the multimode fiber exit end can emit a diverging cylindrical beam or a ring beam, and the ring laser beam is the processing requirement; when the multimode fiber exit end emits a ring beam, the multi-axis adjustment platform is adjusted by fine-tuning 12 It is also possible to change the spatial dimensions of the ring beam. Complete the ring laser beam and its space size according to the design requirements, close the shutter 4, and the setting is completed.

S3, vertically insert the outgoing end of the multimode optical fiber into the UV-curable adhesive film 14 on the glass slide 13, and keep a preset distance from the glass slide 13, open the laser shutter 6, and the ring-shaped laser beam irradiates the UV-curable adhesive film 14. Expose, then close the laser shutter 6 and remove the multimode fiber;

S4, cleaning and separation. The UV-curable adhesive film 14 is cleaned by the developer to remove the unexposed UV-curable adhesive on the surface of the substrate. The exposed UV-curable adhesive forms polymer hollow microtubes. The polymer hollow microtubes are removed from the slide with absolute ethanol. 13 Separation. The isolated polymeric hollow microtubules required continuous exposure to UV light for more than two hours to fully cure their structures.

In this embodiment, the preparation equipment of polymer hollow microtubes has low cost and simple process operation. The preparation of polymer hollow microtubes is formed in one time, and the preparation process is efficient and repeatable, which greatly reduces the microcontact based on polymer hollow microtubes. The cost of the force fiber optic sensing probe is easy to mass-produce the fiber optic sensing probe. In addition, the laser incident angle can be changed by fine-tuning the multi-axis adjustment platform, thereby preparing polymer hollow microtubes of different sizes; integrating polymer hollow microtubes of different sizes into the micro-contact force fiber sensing probe can obtain different Sensing sensitivity, suitable for various application scenarios with different sensitivity requirements.

The above description is only a preferred embodiment of the present invention, but the protection scope of the present invention is not limited to this. The equivalent replacement or change of the inventive concept thereof shall be included within the protection scope of the present invention.

Claims (8)

1. A method for preparing a polymer hollow microtube, which is characterized by comprising the following steps:

s1, dripping ultraviolet curing adhesive on the surface of the substrate, and forming an ultraviolet curing adhesive film through spin coating;

s2, arranging a multimode optical fiber and an ultraviolet laser, wherein laser generated by the ultraviolet laser irradiates the end face of the incident end of the multimode optical fiber through focusing, and the emergent end of the multimode optical fiber is controlled to emit annular laser beams by adjusting the incident angle of the laser;

s3, vertically inserting the emergent end of the multimode optical fiber into the ultraviolet curing adhesive film and keeping a preset distance with the substrate, opening a laser shutter, exposing the ultraviolet curing adhesive film by the annular laser beam, closing the laser shutter, and removing the multimode optical fiber;

and S4, cleaning and separating, and forming the polymer hollow microtube by the ultraviolet curing glue exposed on the surface of the substrate.

2. The method for preparing the polymer hollow microtube of claim 1, wherein in S1, the type of the ultraviolet curing glue is NOA 65.

3. The method as claimed in claim 1, wherein in S1, the thickness of the UV-curable adhesive film is 150-200 μm.

4. The method as claimed in claim 1, wherein in S2, the length of the multimode fiber is 1-3m, and the core diameter is 100-105 μm.

5. The method as claimed in claim 1, wherein in S2, the laser wavelength generated by the UV laser is 385-405nm, and the spot size is 4-6 mm.

6. The method for preparing a polymer hollow microtube according to claim 1, wherein in S2, laser light generated by an ultraviolet laser is focused through a lens.

7. The method as claimed in claim 6, wherein in S2, the lens has a magnification of 40 and a numerical aperture of 0.65.

8. The method for preparing a polymeric hollow microtube according to any one of claims 1 to 7, wherein S4 specifically comprises: and cleaning the ultraviolet curing adhesive film by using a developing solution, removing the unexposed ultraviolet curing adhesive on the surface of the substrate, forming the polymer hollow microtube by using the exposed ultraviolet curing adhesive, and separating the polymer hollow microtube from the substrate by using absolute ethyl alcohol.

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