An imaging device and imaging method for a single-mode optical fiber

Abstract

The application discloses an imaging device and method for a single-mode optical fiber, and belongs to the technical field of optical imaging. An imaging carrier is provided with a scanning end and a non-scanning end, and the non-scanning end is connected with a light source and an image acquisition module. A magnetic extension and contraction driving unit is arranged on the outer wall of the imaging carrier and close to the scanning end. The imaging carrier and the magnetic extension and contraction driving unit are arranged in a fixed base. The scanning end of the imaging carrier extends out of the fixed base. The magnetic extension and contraction driving unit comprises X-axis magnetic extension and contraction units and Y-axis magnetic extension and contraction units which are arranged at intervals. A magnetic field control unit provides sinusoidal alternating current for the X-axis magnetic extension and contraction units and the Y-axis magnetic extension and contraction units, so that periodic extension and contraction deformation is generated, and the scanning end of the imaging carrier is driven to form a Lissajous trajectory along an X-Y plane. The application realizes double-axis driving, has no mechanical wear, fast response, controllable deformation, can stably form a Lissajous scanning trajectory, improves imaging coverage uniformity and imaging efficiency, and has small volume and wide application range.

Description

Technical Field

[0001] This invention belongs to the field of optical imaging technology, and more specifically relates to an imaging device and imaging method for single-mode optical fiber. Background Technology

[0002] Fiber optic scanning imaging technology is widely used in fields such as medical endoscopy and industrial inspection due to its small size, high flexibility and high resolution.

[0003] Existing fiber optic scanning drive methods mainly include piezoelectric drive, motor drive, and electromagnetic drive. Although piezoelectric drive has a fast response, its displacement output is small, making it difficult to meet the needs of large-area scanning, and it is easily affected by temperature, causing trajectory drift. Motor drive (such as micro stepper motors) is large in size, making it unsuitable for miniaturized scenarios such as minimally invasive endoscopes, and its scanning trajectory is mostly linear or circular, resulting in low coverage efficiency. Electromagnetic drive has limited potential for miniaturization and mostly uses simple periodic trajectory scanning.

[0004] Existing single-mode fiber optic scanning endoscopes generally employ electromagnetic drive combined with helical resonant scanning or linear reciprocating scanning. However, this driving method and scanning trajectory suffer from uneven scanning coverage and poor adaptability to irregular cavities. Furthermore, helical scanning requires continuous adjustment of the magnetic field strength to maintain the helical trajectory, which can easily lead to imaging distortion due to magnetic field fluctuations; linear scanning requires multiple stitches to cover the detection area, resulting in low imaging efficiency.

[0005] Lissajous trajectories are formed by driving two orthogonal periodic signals, featuring wide scanning coverage, uniform pixel density, and high scanning efficiency. Magnetically extensible materials offer advantages such as fast magnetic field response and strong deformation control. However, their application in fiber optic scanning is mostly limited to single-direction driving, unable to directly achieve the "independent and coordinated periodic deformation in both the X and Y directions" required for Lissajous scanning. Existing technologies lack a dual-axis drive structure designed specifically for the characteristics of magnetically extensible materials, making it difficult to meet the requirements of Lissajous scanning for trajectory stability and scanning range, thus limiting the application of single-mode fiber optic endoscopes in high-precision, large-area imaging scenarios. Summary of the Invention

[0006] In view of this, the present invention provides an imaging device and imaging method for single-mode optical fiber, which realizes Lissajous trajectory scanning of single-mode optical fiber through a biaxial magnetic drive structure, thereby improving the uniformity and efficiency of imaging coverage.

[0007] To achieve the above objectives, the present invention adopts the following technical solution: An imaging device for single-mode optical fiber includes a fixed base, an imaging carrier, a magnetic expansion drive unit, and a magnetic field control unit. The imaging carrier has a scanning end and a non-scanning end, the non-scanning end being connected to a light source and an image acquisition module. The magnetic expansion drive unit is disposed on the outer wall of the imaging carrier, close to the scanning end. The imaging carrier and the magnetic expansion drive unit are disposed within the fixed base. The scanning end of the imaging carrier extends outside the fixed base. The magnetic field control unit is electrically connected to the magnetic expansion drive unit. The magnetic expansion drive unit includes an X-axis magnetic expansion unit and a Y-axis magnetic expansion unit spaced apart along the axial direction of the imaging carrier. The magnetic field control unit controls the X-axis and Y-axis magnetic expansion units to generate periodic expansion and contraction deformations, causing the scanning end to form a Lissajous trajectory along the XY plane.

[0008] Furthermore, the imaging carrier is a single-mode optical fiber with a diameter of 100μm-150μm.

[0009] Furthermore, the fixing base is made of a non-magnetic alloy.

[0010] Furthermore, the X-axis magnetic expansion unit includes an X-axis magnetic expansion sheet and an X-axis excitation coil; the Y-axis magnetic expansion unit includes a Y-axis magnetic expansion sheet and a Y-axis excitation coil; the X-axis magnetic expansion sheet and the Y-axis magnetic expansion sheet are semi-enclosed on the outer wall of the imaging carrier, and are arranged at 90° to each other along the circumference of the imaging carrier; the X-axis excitation coil is wound around the periphery of the X-axis magnetic expansion sheet and the imaging carrier, and the Y-axis excitation coil is wound around the periphery of the Y-axis magnetic expansion sheet and the imaging carrier; the magnetic field control unit is electrically connected to the X-axis excitation coil and the Y-axis excitation coil.

[0011] Furthermore, the X-axis magnetic expansion unit also includes an X-axis permanent magnet; the Y-axis magnetic expansion unit also includes a Y-axis permanent magnet; the X-axis permanent magnet and the Y-axis permanent magnet are respectively sleeved outside the X-axis excitation coil and the Y-axis excitation coil, and are used to provide a bias magnetic field for the X-axis excitation coil and the Y-axis excitation coil.

[0012] Furthermore, the magnetic field control unit inputs sinusoidal alternating currents of different frequencies in an integer ratio to the X-axis excitation coil and the Y-axis excitation coil, respectively, so that they generate periodically changing X-axis and Y-axis magnetic fields, causing the X-axis magnetic expansion piece and the Y-axis magnetic expansion piece to expand and contract in simple harmonic motion as the magnetic field changes.

[0013] Furthermore, the driving displacement of the X-axis magnetic expansion joint and the Y-axis magnetic expansion joint is 0.1-1mm.

[0014] Furthermore, the outer diameter of the X-axis magnetic expansion piece and the Y-axis magnetic expansion piece are ≤2mm, and the length is ≤30mm.

[0015] Furthermore, a mass block is attached to the non-scanning end of the imaging carrier, positioned 0-5 mm from the end of the non-scanning end.

[0016] The present invention also provides an imaging method using the imaging device for single-mode optical fiber as described above, comprising the following steps: S1. Roughen the outer wall of the scanning end of the imaging carrier, and fix the X-axis magnetic expansion unit and the Y-axis magnetic expansion unit at intervals to the outer wall of the imaging carrier, with the X-axis magnetic expansion unit and the Y-axis magnetic expansion unit being staggered along the circumference of the imaging carrier. S2. Fix both the non-scanning end of the imaging carrier and the magnetic stretching drive unit in the fixed base to ensure that there is no contact or magnetic field interference between the X-axis magnetic stretching unit and the Y-axis magnetic stretching unit; S3. Connect the X-axis excitation coil of the X-axis magnetic expansion unit and the Y-axis excitation coil of the Y-axis magnetic expansion unit to the output terminal of the magnetic field control unit respectively. Connect the non-scanning end of the imaging carrier to the light source and the image acquisition module to complete the assembly of the imaging device. S4. Place the imaging device from S3 at the position to be imaged; S5. Activate the magnetic field control unit to drive the X-axis magnetic expansion unit and the Y-axis magnetic expansion unit to generate periodic expansion and contraction deformation, thereby causing the scanning end of the imaging carrier to form a Lisajous trajectory along the XY plane.

[0017] The beneficial effects of this invention are as follows: This invention uses magnetostrictive material as the driving element, which has no mechanical wear, long service life, fast response speed, and strong deformation controllability.

[0018] By inputting sinusoidal alternating currents with different frequencies in integer ratios into the X-axis and Y-axis magnetic expansion units respectively, Lissajous trajectory scanning can be directly and stably achieved. Compared with traditional spiral scanning and linear scanning, the imaging coverage is more uniform and the imaging efficiency is higher.

[0019] The X-axis and Y-axis magnetic expansion plates can drive displacements of 0.1-1mm, which can improve the coverage density of the Lissajous trajectory and adapt to the needs of large field-of-view imaging.

[0020] The scanning range can be changed by adjusting the current amplitude of the X-axis excitation coil and the Y-axis excitation coil, and the scanning frequency can be adjusted by the magnetic field frequency, which can adapt to different detection scenarios and has a wide range of applications.

[0021] The device is small in size and can be adapted to minimally invasive endoscopes, and the imaging carrier is compatible with existing optical detection systems; a mass block is set at the non-scanning end to form an asymmetric fiber cantilever, which decouples the X / Y axis resonant frequencies and improves scanning stability and imaging quality. Attached Figure Description

[0022] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the provided drawings without creative effort.

[0023] Figure 1 This is a schematic diagram of the overall structure of the imaging device of the present invention.

[0024] Figure 2 This is a three-dimensional structural diagram of the magnetically extended drive unit of the present invention.

[0025] Figure 3 This is a schematic diagram of the structure of the X-axis magnetic expansion joint and the Y-axis magnetic expansion joint of the present invention.

[0026] In the figure: 1-Fixed base; 2-Imaging carrier; 21-Scanning end; 22-Non-scanning end; 23-Mass block; 3-Magnetic expansion drive unit; 31-X-axis magnetic expansion unit; 311-X-axis magnetic expansion sheet; 312-X-axis excitation coil; 313-X-axis permanent magnet; 32-Y-axis magnetic expansion unit; 321-Y-axis magnetic expansion sheet; 322-Y-axis excitation coil; 323-Y-axis permanent magnet. Detailed Implementation

[0027] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0028] Please see the appendix Figure 1-3 The present invention provides an imaging device and imaging method for single-mode optical fiber, including a fixed base 1, an imaging carrier 2, a magnetic stretching drive unit 3, and a magnetic field control unit.

[0029] The imaging carrier 2 is equipped with a scanning end 21 and a non-scanning end 22. The non-scanning end 22 is connected to the light source and the image acquisition module.

[0030] In one embodiment of the present invention, the imaging carrier 2 is a single-mode optical fiber with a diameter of 100μm-150μm.

[0031] The magnetically extended drive unit 3 is synchronously disposed within the fixed base 1 along with the imaging carrier 2, with the scanning end of the imaging carrier 2 extending out of the fixed base to form a cantilever. The magnetically extended drive unit 3 is disposed on the outer wall of the imaging carrier 2, close to the scanning end 21.

[0032] The magnetic stretching drive unit 3 includes an X-axis magnetic stretching unit 31 and a Y-axis magnetic stretching unit 32 that are spaced apart along the axial direction of the imaging carrier 2.

[0033] Furthermore, the X-axis magnetic expansion unit 31 includes an X-axis magnetic expansion plate 311, an X-axis excitation coil 312, and an X-axis permanent magnet 313; the Y-axis magnetic expansion unit 32 includes a Y-axis magnetic expansion plate 321, a Y-axis excitation coil 322, and a Y-axis permanent magnet 323.

[0034] The X-axis magnetic expansion joint 311 and the Y-axis magnetic expansion joint 321 are semi-enclosed on the outer wall of the imaging carrier 2, and are arranged at 90° along the circumference of the imaging carrier 2; the X-axis magnetic expansion joint 311 and the Y-axis magnetic expansion joint 321 are spaced apart from each other.

[0035] The X-axis excitation coil 312 is wound around the X-axis magnetic expansion plate 311 and the imaging carrier 2, and the Y-axis excitation coil 322 is wound around the Y-axis magnetic expansion plate 321 and the imaging carrier 2.

[0036] The X-axis permanent magnet 313 and the Y-axis permanent magnet 323 are respectively sleeved outside the X-axis excitation coil 312 and the Y-axis excitation coil 322. The X-axis permanent magnet 313 and the Y-axis permanent magnet 323 are used to provide a bias magnetic field (H). bias =80–120kA / m), alternating magnetic field coil drives expansion and contraction vibration.

[0037] The magnetic field control unit is electrically connected to the X-axis excitation coil 312 and the Y-axis excitation coil 322, and is used to control the X-axis magnetic stretching plate 311 and the Y-axis magnetic stretching plate 321 to produce periodic stretching deformation, which synchronously drives the scanning end 21 of the imaging carrier 2 to form a Lisajous trajectory along the XY parallel plane.

[0038] The magnetic field control unit can input sinusoidal alternating current of different frequencies to the X-axis excitation coil 312 and the Y-axis excitation coil 322 respectively, so that they generate periodically changing X-axis and Y-axis magnetic fields, causing the X-axis magnetic expansion plate 311 and the Y-axis magnetic expansion plate 321 to expand and contract with the change of magnetic field and perform simple harmonic motion.

[0039] Both the X-axis magnetic expansion joint 311 and the Y-axis magnetic expansion joint 321 are made of magnetostrictive material. This material has no mechanical wear and its service life is more than 5 times longer than that of motor-driven materials. Magnetic expansion joints have the advantages of fast magnetic field response and strong deformation control. Using magnetic expansion joints meets the requirements of Lissajous scanning for trajectory stability and scanning range, directly realizing the "independent and coordinated periodic deformation in both the X and Y directions" required by Lissajous scanning, and enabling the application of single-mode fiber optic endoscopes in high-precision, large-area imaging scenarios.

[0040] By setting the X-axis magnetic expansion plate 311 and Y-axis magnetic expansion plate 321 to drive displacements of 0.1-1mm, the coverage density of the Lissajous trajectory is improved, scanning efficiency is increased, and it is suitable for large field-of-view imaging requirements. Furthermore, using the Lissajous scanning trajectory, compared to traditional helical scanning, eliminates the need for continuous adjustment of the magnetic field strength, resulting in a stable scanning trajectory and more uniform imaging coverage. Based on dual-axis drive using magnetic expansion materials, the response speed is fast, the scanning frequency can be adjusted via the magnetic field frequency, and imaging efficiency is high. It is compatible with minimally invasive endoscopes, and the imaging carrier design is compatible with existing optical detection systems, making it suitable for a wide range of applications. Moreover, the deformation of the magnetic expansion material is highly controllable; the scanning range can be changed by adjusting the magnetic current amplitude of the X-axis excitation coil 312 and the Y-axis excitation coil 322, adapting to different detection scenarios.

[0041] In one embodiment of the present invention, both the X-axis magnetic expansion joint 311 and the Y-axis magnetic expansion joint 321 can be made of Terfenol-D material.

[0042] In one embodiment of the present invention, the fixed base 1 is made of a non-magnetic alloy to avoid interfering with the magnetic field distribution.

[0043] In one embodiment of the present invention, the outer diameter of the X-axis magnetic expansion joint 311 and the Y-axis magnetic expansion joint 321 is ≤2mm, and the length of the X-axis magnetic expansion joint 311 and the Y-axis magnetic expansion joint 321 is ≤30mm.

[0044] The method for fabricating the imaging device is as follows: Fabrication of magnetic extensibility drive unit 3: Terfenol-D material is cut into thin sheets with a thickness of 0.1-0.3mm, and the surface is plated with nickel for rust prevention. Enamelled wire is wound on the outside of the thin sheet as X-axis excitation coil 312 and Y-axis excitation coil 322. The number of coil turns is 50-100 turns, thus making X-axis magnetic extensibility unit 31 and Y-axis magnetic extensibility unit 32. Fiber optic assembly: Take a 125μm diameter single-mode fiber and roughen the outer wall of its scanning end 21 (5-10mm in length). Vertically attach the X-axis magnetic expansion unit 31 and the Y-axis magnetic expansion unit 32 to different sections of the outer wall of the imaging carrier 2 using high-temperature resistant epoxy adhesive. The adhesive layer thickness is ≤0.05mm, the curing temperature is 80℃, and the curing time is 2 hours. The X-axis magnetic expansion sheet 311 and the Y-axis magnetic expansion sheet 321 are fixed to the imaging carrier 2 by adhesive bonding through a sheet-like structure, or formed on the imaging carrier 2 as a magnetostrictive thin film by magnetron sputtering.

[0045] Base fixing: The non-scanning end of the imaging carrier 2 and the magnetic stretching drive unit 3 are fixed in the non-magnetic alloy fixed base 1 to ensure that the X-axis magnetic stretching unit 31 and the Y-axis magnetic stretching unit 32 have no contact and no magnetic field interference; Module connection: Connect the X-axis excitation coil 312 and the Y-axis excitation coil 322 to the output end of the magnetic field control unit respectively, and connect the non-scanning end 22 of the imaging carrier 2 to the light source and the image acquisition module to complete the probe assembly.

[0046] Asymmetric structure assembly: The non-scanning end 22 of the imaging carrier 2 is bonded to the mass block 23 using a curing adhesive and cured with a UV lamp, with the mass block 23 positioned 0-5mm from the end. The mass block 23 forms an asymmetric fiber cantilever at the scanning end 21 of the imaging carrier 2, decoupling the X / Y axis resonant frequencies.

[0047] The working principle of this invention is as follows: The magnetic field control unit inputs a sinusoidal alternating current with frequency f1 to the X-axis excitation coil 312, generating a periodically changing X-axis magnetic field. This causes the X-axis magnetic expansion plate 311 to expand and contract with the magnetic field, driving the single-mode optical fiber to perform simple harmonic motion in the X direction. Simultaneously, a sinusoidal alternating current with frequency f2 is input to the Y-axis excitation coil 322, generating a periodically changing Y-axis magnetic field. This causes the Y-axis magnetic expansion plate to drive the single-mode optical fiber to perform simple harmonic motion in the Y direction. Here, f1 ≠ f2, and f1 and f2 are integer ratios.

[0048] The signal generator outputs two sine waves: V x =A sin(2πf x t), V y =B sin(2πf y t+ Phase difference =π / 2. The frequency matching algorithm adjusts f in real time. x / f y Compensation for temperature drift (error <0.1Hz).

[0049] An alternating current generates a magnetic field H = H0 sin(ωt). Two sinusoidal signals are input to drive the alternating magnetic field, causing the cantilever formed by the scanning end 21 of the imaging carrier 2 to resonate and vibrate along the X / Y axes. A bias magnetic field is applied to pre-polarize the magnetostrictive film, and the expansion and contraction of the magnetostrictive film drives the cantilever to vibrate. The two orthogonal vibrations are combined to form a Lissajous trajectory for image acquisition. The resonant frequency drift can be compensated for in real time using a frequency matching algorithm.

[0050] The amplitude control circuit uses PID closed-loop feedback and monitors the amplitude in real time through fiber Bragg grating (FBG).

[0051] Frequency amplitude modulation signal (AM-Sine) improves scanning uniformity (coverage >95%).

[0052] The scanning end 21 of the imaging carrier 2 moves synchronously under the superposition of simple harmonic motions in the X and Y directions, forming a Lissajous scanning trajectory. During the scanning process, the optical signal transmitted by the optical fiber is processed by the image acquisition module to obtain a complete image of the detection area.

[0053] The present invention also proposes an imaging method using the above-mentioned imaging device for single-mode optical fiber, comprising the following steps: S1. Roughen the outer wall of the scanning end 21 of the imaging carrier 2, and fix the X-axis magnetic expansion unit 31 and the Y-axis magnetic expansion unit 32 to the outer wall of the imaging carrier 2 respectively, and the X-axis magnetic expansion unit 31 and the Y-axis magnetic expansion unit 32 are staggered along the circumference of the imaging carrier 2.

[0054] S2. Fix both the non-scanning end 22 of the imaging carrier 2 and the magnetic stretching drive unit 3 in the fixed base 1 to ensure that there is no contact or magnetic field interference between the X-axis magnetic stretching unit 31 and the Y-axis magnetic stretching unit 32.

[0055] S3. Connect the X-axis excitation coil 312 of the X-axis magnetic expansion unit 31 and the Y-axis excitation coil 322 of the Y-axis magnetic expansion unit 32 to the output end of the magnetic field control unit respectively. Connect the non-scanning end 22 of the imaging carrier 2 to the light source and the image acquisition module to complete the assembly of the imaging device.

[0056] S4. Place the imaging device from S3 at the position to be imaged.

[0057] S5. Activate the magnetic field control unit to drive the X-axis magnetic expansion unit 31 and the Y-axis magnetic expansion unit 32 to generate periodic expansion and contraction deformation, thereby causing the scanning end 21 of the imaging carrier 2 to form a Lisajous trajectory along the XY plane.

[0058] The various embodiments in this specification are described in a progressive manner, with each embodiment focusing on its differences from other embodiments. Similar or identical parts between embodiments can be referred to interchangeably. For the apparatus disclosed in the embodiments, since it corresponds to the method disclosed in the embodiments, the description is relatively simple; relevant parts can be referred to the method section.

[0059] The above description of the disclosed embodiments enables those skilled in the art to make or use the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. An imaging device for single-mode optical fiber, characterized in that, It includes a fixed base (1), an imaging carrier (2), a magnetic stretching drive unit (3), and a magnetic field control unit; The imaging carrier (2) is provided with a scanning end (21) and a non-scanning end (22), and the non-scanning end (22) is connected to the light source and the image acquisition module; the magnetic stretching drive unit (3) is disposed on the outer wall of the imaging carrier (2) and close to the scanning end (21); the imaging carrier (2) and the magnetic stretching drive unit (3) are disposed inside the fixed base (1); the scanning end (21) of the imaging carrier (2) extends out of the fixed base (1); The magnetic field control unit is electrically connected to the magnetic stretching drive unit (3); the magnetic stretching drive unit (3) includes an X-axis magnetic stretching unit (31) and a Y-axis magnetic stretching unit (32) spaced apart along the axial direction of the imaging carrier (2); the magnetic field control unit is used to control the X-axis magnetic stretching unit (31) and the Y-axis magnetic stretching unit (32) to generate periodic stretching deformation, thereby driving the scanning end (21) to form a Lissajous trajectory along the XY plane.

2. The imaging device for single-mode optical fiber according to claim 1, characterized in that, The imaging carrier (2) is a single-mode optical fiber with a diameter of 100μm-150μm.

3. The imaging device for single-mode optical fiber according to claim 1, characterized in that, The fixed base (1) is made of a non-magnetic alloy.

4. The imaging device for single-mode optical fiber according to claim 1, characterized in that, The X-axis magnetic expansion unit (31) includes an X-axis magnetic expansion sheet (311) and an X-axis excitation coil (312); the Y-axis magnetic expansion unit (32) includes a Y-axis magnetic expansion sheet (321) and a Y-axis excitation coil (322); the X-axis magnetic expansion sheet (311) and the Y-axis magnetic expansion sheet (321) are semi-enclosed on the outer wall of the imaging carrier (2), and the two are arranged at 90° along the circumference of the imaging carrier (2); the X-axis excitation coil (312) is wound around the periphery of the X-axis magnetic expansion sheet (311) and the imaging carrier (2), and the Y-axis excitation coil (322) is wound around the periphery of the Y-axis magnetic expansion sheet (321) and the imaging carrier (2); the magnetic field control unit is electrically connected to the X-axis excitation coil (312) and the Y-axis excitation coil (322).

5. The imaging device for single-mode optical fiber according to claim 4, characterized in that, The X-axis magnetic expansion unit (31) further includes an X-axis permanent magnet (313); the Y-axis magnetic expansion unit (32) further includes a Y-axis permanent magnet (323); the X-axis permanent magnet (313) and the Y-axis permanent magnet (323) are respectively sleeved outside the X-axis excitation coil (312) and the Y-axis excitation coil (322) to provide a bias magnetic field for the X-axis excitation coil (312) and the Y-axis excitation coil (322).

6. The imaging device for single-mode optical fiber according to claim 4, characterized in that, The magnetic field control unit inputs sinusoidal alternating currents with different frequencies and frequencies in integer ratios to the X-axis excitation coil (312) and the Y-axis excitation coil (322), respectively, so that they generate periodically changing X-axis and Y-axis magnetic fields, causing the X-axis magnetic expansion piece (311) and the Y-axis magnetic expansion piece (321) to expand and contract with the change of magnetic field and perform simple harmonic motion.

7. The imaging device for single-mode optical fiber according to claim 4, characterized in that, The driving displacement of the X-axis magnetic expansion piece (311) and the Y-axis magnetic expansion piece (321) is 0.1-1mm.

8. The imaging device for single-mode optical fiber according to claim 4, characterized in that, The outer diameter of the X-axis magnetic expansion piece (311) and the Y-axis magnetic expansion piece (321) is ≤2mm and the length is ≤30mm.

9. The imaging device for single-mode optical fiber according to claim 1, characterized in that, The non-scanning end (22) of the imaging carrier (2) is attached with a mass block (23) at a distance of 0-5 mm from the end of the non-scanning end.

10. An imaging method using an imaging apparatus for single-mode optical fiber as described in any one of claims 1-9, characterized in that, Includes the following steps: S1. Roughen the outer wall of the scanning end (21) of the imaging carrier (2), and fix the X-axis magnetic expansion unit (31) and the Y-axis magnetic expansion unit (32) at intervals on the outer wall of the imaging carrier (2), and the X-axis magnetic expansion unit (31) and the Y-axis magnetic expansion unit (32) are staggered along the circumference of the imaging carrier (2); S2. Fix the non-scanning end (22) of the imaging carrier (2) and the magnetic stretching drive unit (3) in the fixed base (1) to ensure that there is no contact or magnetic field interference between the X-axis magnetic stretching unit (31) and the Y-axis magnetic stretching unit (32); S3. Connect the X-axis excitation coil (312) of the X-axis magnetic expansion unit (31) and the Y-axis excitation coil (322) of the Y-axis magnetic expansion unit (32) to the output end of the magnetic field control unit respectively. Connect the non-scanning end (22) of the imaging carrier (2) to the light source and the image acquisition module to complete the assembly of the imaging device. S4. Place the imaging device from S3 at the position to be imaged; S5. Start the magnetic field control unit to drive the X-axis magnetic expansion unit (31) and the Y-axis magnetic expansion unit (32) to generate periodic expansion and contraction deformation, thereby causing the scanning end (21) of the imaging carrier (2) to form a Lisajous trajectory along the XY plane.

Images