Vision and optical feedback combined optical element rapid alignment method and device

Abstract

The invention relates to a visual and optical feedback combined optical element rapid alignment method and device, and the method comprises the steps: plane mirror alignment and beam splitter prism alignment, the plane mirror alignment establishes a reference optical axis for beam splitter prism alignment, and visual feedback coarse alignment and optical feedback fine alignment are successively adopted in the two stages. During visual feedback coarse alignment, the inclination angle of the plane mirror or the beam splitter prism is calculated and adjusted according to the coordinates of light spots on the imaging screen, so that the light spots return to the target center or coincide with the target center; during optical feedback fine alignment, spiral gradient rising is adopted to search and adjust the inclination angle of the beam splitter prism, so that the reflected light intensity is maximum. The alignment device comprises a clamp which is used for fixing a gradient refractive index lens and is provided with an imaging screen in the direction of a light emitting surface, a side surface imaging device, a first rotating platform fixed with a plane mirror, a second rotating platform for clamping a beam splitter prism and the like. By utilizing the method and the device, the alignment precision and the alignment efficiency of the gradient refractive index lens, the beam splitter prism and other optical elements can be improved.

Description

Technical Field

[0001] This application belongs to the field of precision assembly of optical components, specifically a method and apparatus for rapid alignment of optical components that combines visual and optical feedback. Background Technology

[0002] Alignment between optical components is a core issue in the assembly process of precision optical instruments and devices, directly affecting the accuracy and performance of the instruments. Traditional precision alignment methods mainly rely on manual adjustment, which is inefficient and cannot meet the needs of mass automated production. Therefore, there is an urgent need for a method to achieve high-precision automatic alignment of optical components.

[0003] CN119282947A discloses a precision automatic alignment system and method for optical lenses and negative pressure clamps, which can achieve automatic precision alignment between optical lenses and negative pressure clamps by using an image processing system to process images acquired by an image acquisition device. However, the alignment accuracy of this scheme depends on the accuracy of the image acquisition device, which is difficult to meet the sub-micron level alignment accuracy requirements of high-performance optical instruments.

[0004] CN119290174A discloses a system and method for spatial alignment detection and correction of optical field based on an optical interferometer. The system comprises a second beam splitter, a third beam splitter, a first plane mirror, a second plane mirror, a Dove prism, a first photodetector, and a second photodetector. This system and method can achieve alignment detection of two beams at different wavelengths. However, the system has a relatively complex structure and large size, making it difficult to meet the high integration requirements of precision optical instrument assembly systems.

[0005] Existing optical component alignment methods rely on a single alignment feedback mechanism, which has several limitations. While visual feedback alone can quickly acquire approximate position and orientation information of components over a large field of view, achieving alignment, its inherent accuracy limitations make it difficult to meet the requirements of high-precision alignment. Conversely, while optical feedback can theoretically achieve high alignment accuracy, the process of searching for the optimal alignment state is often somewhat haphazard when initial positional deviations are large, requiring significant time for repeated adjustments and resulting in low alignment efficiency.

[0006] Therefore, it is of great practical significance to develop a rapid alignment method and device for optical elements that combines visual and optical feedback, can improve alignment accuracy and efficiency, and has good adaptability and economy. Summary of the Invention

[0007] This invention provides a method and apparatus for rapid alignment of optical elements by combining visual and optical feedback, which can improve the alignment accuracy and efficiency between optical elements.

[0008] The technical solution of this application is as follows:

[0009] This application provides a rapid alignment device for optical elements that combines visual and optical feedback, including: a laser, a circulator, a photodetector, a controller, and a base;

[0010] A plane mirror is mounted on the base via a first rotating platform;

[0011] A first optical element is mounted on the base via a second rotating platform, and the first optical element is positioned below the plane mirror;

[0012] The second optical element is mounted on the base by a clamp. The second optical element is located below the first optical element, and the upper surface of the clamp serves as an imaging screen for the reflected light of the plane mirror.

[0013] A side-view imaging device, which is mounted on the base;

[0014] A visual feedback device, which is mounted on the base;

[0015] The output of the laser is connected to the second optical element via a circulator, the other output of the circulator is connected to the photodetector, and the output of the photodetector is connected to the controller.

[0016] The controller's input is connected to the visual feedback device, and its output is connected to the first rotating platform and the second rotating platform;

[0017] The center of the planar reflector coincides with the rotation center of the first rotating platform;

[0018] The center of the first optical element coincides with the rotation center of the second rotating platform;

[0019] The rotation center of the first rotating platform, the rotation center of the second rotating platform, and the central axis of the fixture are arranged on the same axis;

[0020] The side-view imaging device is arranged parallel to the axis.

[0021] Preferably, the visual feedback device includes:

[0022] A first side-viewing vision device is fixed on the base and arranged parallel to the side-viewing imaging device. The axis of the first side-viewing vision device is perpendicular to the orthogonal plane of the first optical element and the orthogonal plane of the second optical element. The field of view of the first side-viewing vision device covers the docking area of ​​the first optical element and the second optical element.

[0023] The second side-viewing vision device is fixed on the base and arranged perpendicular to the side-viewing imaging device. The field of view of the second side-viewing vision device covers the docking area of ​​the first optical element and the second optical element.

[0024] A global vision device is fixed on the base, and the axis of the global vision device points to the upper surface of the fixture and the side-view imaging device.

[0025] The intersection of the axes between the first side-view vision device and the second side-view vision device is located on the axis.

[0026] Preferably, during coarse alignment of the planar reflector, the controller controls the second rotating platform to move the first optical element away from the second optical element to the beam path of the planar reflector; after the light emitted by the laser is transmitted through the optical fiber, the outgoing light is collimated by the second optical element and then reflected by the planar reflector onto the imaging screen; the controller controls the first rotating platform to adjust the attitude of the planar reflector according to the image of the light spot position on the imaging screen acquired by the global vision device, so that the reflected beam of the planar reflector points to the center of the end face of the imaging screen;

[0027] During coarse alignment of the first optical element, the controller controls the second rotating platform to move the first optical element into the beam path from the second optical element to the plane mirror. After the light emitted by the laser is transmitted through the optical fiber, the outgoing light is collimated by the second optical element. The collimated outgoing light is then separated into a reference light and a measurement light by the first optical element. The reference light is reflected by the plane mirror to form a first light spot on the side-view imaging device, and the measurement light is directed onto the side-view imaging device to form a second light spot. Based on the image of the light spot position on the side-view imaging device acquired by the global vision device, the controller controls the second rotating platform to adjust the attitude of the first optical element so that the first light spot and the second light spot are close to coinciding.

[0028] Preferably, when precisely aligning the planar reflector, the controller first controls the first rotating platform to rotate to perform a spiral scan, adjusting the tilt angle of the planar reflector; simultaneously, it monitors the light intensity value of the reflected beam from the planar reflector detected by the photodetector. When the light intensity value of the reflected beam from the planar reflector detected by the photodetector exceeds a set threshold, it controls the first rotating platform to rotate to perform an upward search scan until the light intensity value of the reflected beam from the planar reflector detected by the photodetector reaches its maximum value.

[0029] Preferably, when precisely aligning the first optical element, the controller first controls the second rotating platform to rotate to achieve a spiral scan and adjust the tilt angle of the first optical element; simultaneously, it monitors the light intensity value of the reflected beam of the plane mirror detected by the photodetector. When the light intensity value of the reflected beam of the plane mirror detected by the photodetector is greater than a set threshold, it controls the second rotating platform to rotate to achieve an upward search scan until the light intensity value of the reflected beam of the plane mirror detected by the photodetector reaches its maximum value.

[0030] Preferably, when performing coarse alignment of the first optical element, the controller also controls the second rotating platform to adjust the position of the first optical element based on the relative position between the first optical element and the second optical element collected by the first side-view vision device and the second side-view vision device, so that the first optical element and the second optical element are aligned.

[0031] When the first optical element is precisely aligned, a light-absorbing element is provided between the second optical element and the plane mirror to cut off the light path between the second optical element and the plane mirror.

[0032] Preferably, the clamp includes: a clamp base, a clamp cover plate, and a rotating shaft fixing component.

[0033] The clamp cover plate is rotatably connected to the clamp base via the rotating shaft fixing member;

[0034] The upper surface of the clamp cover plate and the clamp base together serve as an imaging screen for the reflected light of the plane mirror;

[0035] The clamp cover plate and the clamp base together form a groove for fixing the second optical element;

[0036] The clamp cover plate and the clamp base share a common axis forming an optical fiber through groove, which connects to the groove.

[0037] The clamp cover plate and the clamp base are also adsorbed and bonded together by a magnetic adsorption component.

[0038] Preferably, the first optical element is a beam splitter prism, and the second optical element is a gradient refractive index lens; the side of the beam splitter prism is coated with a reflective film.

[0039] Preferably, the side-view imaging device is provided with a first flat panel light source, and the center of the first flat panel light source is located on the axis of the first side-view vision device;

[0040] A second flat-panel light source is provided on the second rotating platform, and the center of the second flat-panel light source is located on the axis of the second side-viewing vision device;

[0041] The front surface of the first flat panel light source also serves as the imaging screen of the side-view imaging device, and the first flat panel light source is parallel to the side of the first optical element coated with a reflective film.

[0042] This application also provides a rapid alignment method for optical elements combining visual and optical feedback, applied to the aforementioned rapid alignment device for optical elements combining visual and optical feedback, the method comprising:

[0043] After coarse and fine alignment of the plane mirror, coarse and fine alignment of the first optical element are performed sequentially.

[0044] The coarse alignment step of the planar reflector includes: the controller controls the second rotating platform to move the first optical element away from the second optical element to the beam path of the planar reflector, and then controls the laser to emit light; after the light emitted by the laser is transmitted through an optical fiber, the emitted light is collimated by the second optical element and then reflected by the planar reflector onto the imaging screen; the controller controls the first rotating platform to adjust the attitude of the planar reflector according to the image of the light spot position on the imaging screen acquired by the global vision device, so that the reflected beam of the planar reflector points to the center of the end face of the imaging screen;

[0045] The steps for precisely aligning the planar reflector include: the controller first controls the first rotating platform to rotate to perform a helical scan, adjusting the tilt angle of the planar reflector; simultaneously, it monitors the light intensity value of the reflected beam from the planar reflector detected by the photodetector; when the light intensity value of the reflected beam from the planar reflector detected by the photodetector is greater than a set threshold, it first controls the first rotating platform to rotate to perform an upward search scan until the light intensity value of the reflected beam from the planar reflector detected by the photodetector reaches its maximum value;

[0046] The coarse alignment step for the first optical element includes: the controller controls the second rotating platform to move the first optical element into the beam path from the second optical element to the plane mirror, and then controls the laser to emit light; after the light emitted by the laser is transmitted through the optical fiber, the outgoing light is collimated by the second optical element, and the collimated outgoing light is separated into a reference light and a measurement light by the first optical element; the reference light is reflected by the plane mirror to form a first light spot on the side-view imaging device, and the measurement light is directed onto the side-view imaging device to form a second light spot; the controller controls the second rotating platform to adjust the attitude of the first optical element according to the light spot position image on the side-view imaging device acquired by the global vision device, so that the first light spot and the second light spot are close to coincide.

[0047] The step of precisely aligning the first optical element includes: the controller controlling the second rotating platform to adjust the tilt angle of the first optical element; simultaneously, monitoring the light intensity value of the reflected beam of the plane mirror detected by the photodetector; when the light intensity value of the reflected beam of the plane mirror detected by the photodetector is greater than a set threshold, first controlling the second rotating platform to rotate to achieve an upward search scan, until the light intensity value of the reflected beam of the plane mirror detected by the photodetector reaches the maximum value.

[0048] Preferably, the step of coarsely aligning the first optical element further includes: the controller further controls the first rotating platform to perform three-dimensional position adjustment on the first optical element based on the relative position between the first optical element and the second optical element acquired by the first side-view vision device and the second side-view vision device, so that the first optical element and the second optical element are aligned.

[0049] The beneficial effects of this application are as follows:

[0050] This technology enables rapid and precise automatic alignment between the first and second optical elements to be assembled, addressing the limitations of traditional visual alignment methods due to image resolution constraints of optical microscopes, as well as the long alignment times and low efficiency of traditional optical alignment methods. Specifically:

[0051] It enables rapid and precise alignment between the first and second optical elements, improving alignment efficiency. By employing visual feedback for coarse alignment, the beam can quickly approach the alignment area, while simultaneously establishing a reference principal optical axis for the plane mirror. This significantly reduces the search range required for fine alignment of the first optical element, thus decreasing search time.

[0052] The process of precisely aligning the first and second optical elements has been automated. By employing visual and optical feedback, combined with an electric displacement stage to adjust the position of the components to be assembled, a closed-loop control of the alignment process is formed, enabling a fully automated alignment process.

[0053] It is easily integrated into optical component micro-assembly systems. Because the alignment device of this invention is compatible with optical component micro-assembly systems, its components exhibit significant reusability in structure and function. Integrating the alignment device of this invention into a micro-assembly system only requires adding an operator to the existing alignment device to perform the assembly action after alignment, achieving a seamless connection from alignment to assembly, greatly reducing the difficulty and cost of system integration. Attached Figure Description

[0054] Figure 1 This is a schematic diagram of the structure of the optical element rapid alignment device that combines visual and optical feedback in the embodiments of this application;

[0055] Figure 2 This is an enlarged view of the layout relationship of the core parts in the embodiments of this application;

[0056] Figure 3 This is a schematic diagram of the fixture in the unfolded state in the embodiments of this application;

[0057] Figure 4 This is a schematic diagram illustrating the visual coarse alignment principle of the plane mirror in the embodiments of this application;

[0058] Figure 5 This is a schematic diagram of the visual coarse alignment principle of the beam splitter in the embodiments of this application;

[0059] Figure 6 This is a schematic diagram of the transmission of the reflected light beam in the gradient refractive index lens in an embodiment of this application;

[0060] Figure 7 This is a schematic diagram illustrating the visual coarse alignment principle of the plane mirror in the embodiments of this application;

[0061] Figure 8 This is a schematic diagram of the visual coarse alignment principle of the beam splitter in the embodiments of this application;

[0062] Figure 9 This is a three-dimensional schematic diagram of the spiral gradient ascent search principle in the embodiments of this application;

[0063] Figure 10 This is a planar projection view of the spiral gradient ascent search principle in the embodiments of this application;

[0064] Figure 11 This is a schematic diagram of the beam splitter clamping principle in the embodiments of this application;

[0065] Figure 12 This is a schematic diagram of the plane mirror in the unaligned state, captured by the global camera during the coarse alignment process of the plane mirror in an embodiment of this application.

[0066] Figure 13 This is a schematic diagram of the plane mirror in the coarse alignment state, captured by the global camera during the coarse alignment process of the plane mirror in the embodiments of this application.

[0067] Figure 14 The image captured by the second side vision device along the x-axis during the pre-positioning process of the beam splitter in this embodiment of the application;

[0068] Figure 15 The image captured by the first side vision device along the y-axis during the pre-positioning process of the beam splitter in this embodiment of the application.

[0069] Figure 16 The image captured by the global camera in this embodiment of the application is taken when the beam splitter is not coarsely aligned during the coarse alignment process.

[0070] Figure 17 The image captured by the global camera in this embodiment of the application is in the coarse alignment state during the coarse alignment process of the beam splitter.

[0071] Figure 18 This is a curve showing the change of the normalized value of the reflected light intensity as a function of the number of iterations during the beam-splitting prism alignment process in this embodiment of the application.

[0072] Figure 19 This is a schematic diagram of the gripper in the embodiments of this application;

[0073] 1-First pitch turntable, 2-First yaw turntable, 3-Mirror frame, 4-Global vision device, 5-Axis, 6-Second yaw turntable, 7-Second pitch turntable, 8-Side-view imaging device, 9-Clamp, 10-Base, 11-Controller, 12-Photodetector, 13-Circulator, 14-Laser, 15-Second flat panel light source, 16-Gradient refractive index lens, 17-First side-view vision device, 18-Beam splitter prism, 19-Second side-view vision device, 20-Clamp cover plate, 21-Rotation shaft fixing component, 22-Magnetic groove, 23-Clamp base, 24-Plane reflector, 25-Imaging screen; 26-Light absorption element; 27-Holder; 271-Gripper; 272-Force sensor. Detailed Implementation

[0074] like Figure 1 and Figure 2 As shown, this application embodiment provides a rapid alignment device for optical elements that combines visual and optical feedback, including: a laser 14, a circulator 13, a photodetector 12, a controller 11, and a base 10;

[0075] A plane mirror 24 is mounted on the base 10 via a first rotating platform;

[0076] The first optical element is mounted on the base 10 via the second rotating platform, and the first optical element is disposed below the plane mirror 24;

[0077] The second optical element is mounted on the base 10 by a clamp 9. The second optical element is located below the first optical element, and the upper surface of the clamp 9 serves as an imaging screen 25 for the reflected light of the plane mirror 24.

[0078] A side-view imaging device 8 is mounted on the base 10;

[0079] A visual feedback device is mounted on the base 10;

[0080] The output of the laser 14 is connected to the second optical element via the circulator 13, and the other output of the circulator 13 is connected to the photodetector 12. The output of the photodetector 12 is connected to the controller 11.

[0081] The controller 11 is connected to the visual feedback device for input and to the first rotating platform and the second rotating platform for output.

[0082] The center of the plane mirror 24 coincides with the rotation center of the first rotating platform;

[0083] The center of the first optical element coincides with the rotation center of the second rotating platform;

[0084] The rotation center of the first rotating platform, the rotation center of the second rotating platform, and the central axis of the fixture 9 are arranged on the same axis 5;

[0085] The side-view imaging device 8 is arranged parallel to the axis 5.

[0086] In this embodiment of the application, the aforementioned axis 5 is perpendicular to the horizontal upper surface of the base 10.

[0087] The output of the laser 14 is connected to the second optical element to be assembled via the circulator 13, and the other output of the circulator 13 is connected to the photodetector 12. The output of the photodetector 12 is connected to the controller 11.

[0088] The first rotating platform is a two-axis rotating platform, which includes a first pitch turntable 1 and a first yaw turntable 2. The plane mirror 24 is mounted on the first rotating platform via a mirror frame 3.

[0089] The second rotary platform includes a two-axis rotary platform and a three-axis translation stage. The second rotary platform includes a second pitch stage 7 and a second yaw stage 6. The first optical element is mounted on the two-axis rotary platform via a clamp 27. The two-axis rotary platform is mounted on the three-axis translation stage, so that the second rotary platform is a five-axis displacement stage.

[0090] In this embodiment, the fixture 9 is made of resin material using 3D printing, as shown in the reference. Figure 3 The fixture 9 includes: a fixture cover plate 20, a rotating shaft fixing member 21, and a fixture base 23.

[0091] The side of the clamp cover plate 20 is designed with a pivot, which mates with a hole on the side of the clamp base 23. The two can rotate relative to each other and form a cylindrical structure when closed. Once the pivot fixing member 21 is inserted into the pivot, the pivot cannot be removed.

[0092] The upper surfaces of the clamp cover plate 20 and the clamp base 23 are semi-circular disks. After the clamp cover plate 20 and the clamp base 23 are attracted and fixed to each other, the two semi-circular disks form a complete circular disk, which will serve as the imaging screen 25 for the reflected light of the plane mirror 24.

[0093] A semi-circular groove is formed on the upper surface of the clamp cover plate 20 and the upper surface of the clamp base 23 along their respective axes; after the clamp cover plate 20 and the clamp base 23 are attracted and fixed to each other, the two semi-circular grooves together form a groove for clamping the second optical element.

[0094] A semi-circular through hole is formed on the lower surface of the clamp cover plate 20 and the lower surface of the clamp base 23 along their respective axes. After the clamp cover plate 20 and the clamp base 23 are fixed together by adsorption, the two semi-circular through holes together form an optical fiber through hole for the optical fiber to pass through. After the optical fiber passes through the optical fiber through hole from the bottom, it is connected to the second optical element assembled in the groove.

[0095] In this embodiment, the clamp cover plate 20 and the clamp base 23 are further adsorbed and bonded by a magnetic adsorption component. Specifically, the clamp cover plate 20 and the clamp base 23 are respectively provided with opposing magnetic grooves 22, and magnets are installed in the magnetic grooves 22. The relative adsorption and bonding of the clamp cover plate 20 and the clamp base 23 is achieved by the magnetic force of the magnets, thereby achieving the clamping of the second optical element to be assembled.

[0096] The fixture cover plate 20 and fixture base 23 are designed with four pairs of magnets, which are evenly distributed relative to the axis of the fixture 9.

[0097] During operation, the second optical element, which is attracted and fixed by the magnet, first falls from above into the semi-circular groove on the clamp base 23. Then, the clamp cover plate 20 is manually rotated, and under the magnetic attraction of the magnet, the clamp cover plate 20 and the clamp base 23 close together and clamp the second optical element. The upper surfaces of the clamp cover plate 20 and the clamp base 23 together form a large disc-shaped target surface, which serves as the imaging screen 25 to display the direction of the beam reflected by the plane mirror 24.

[0098] Reference Figure 1 and Figure 2 In this embodiment of the application, the visual feedback device includes:

[0099] A first side-viewing vision device 17 is fixed on the base 10 and arranged parallel to the side-viewing imaging device. The field of view of the first side-viewing vision device 17 covers the docking portion of the first optical element and the second optical element.

[0100] The second side-viewing vision device 19 is fixed on the base 10 and arranged perpendicular to the side-viewing imaging device 8. The field of view of the second side-viewing vision device 19 covers the docking portion of the first optical element and the second optical element.

[0101] A global vision device 4 is fixed on the base 10, and the axis of the global vision device 4 points to the upper surface of the clamp 9 and the side-view imaging device 8.

[0102] The intersection of the axes between the first side-viewing vision device 17 and the second side-viewing vision device 19 is located on the axis 5.

[0103] For the first side-viewing vision device 17 and the second side-viewing vision device 19, their axes are respectively set perpendicular to the orthogonal plane of the first optical element and the second optical element.

[0104] The first side-viewing vision device 17 and the second side-viewing vision device 19 acquire images of the docking portion of the first optical element and the second optical element from two directions, respectively, so that the controller 11 can evaluate the positional alignment between the first optical element and the second optical element.

[0105] The first side-viewing vision device 17 and the second side-viewing vision device 19 are composed of cameras with microscope lenses mounted at the front end, and the global vision device 4 is a global camera.

[0106] Reference Figure 2 In this embodiment of the application, the side-view imaging device 8 is provided with a first flat plate light source, and the center of the first flat plate light source is located on the axis of the first side-view vision device 17.

[0107] A second flat panel light source 15 is provided on the second rotating platform, and the center of the second flat panel light source 15 is located on the axis of the second side-viewing vision device 19;

[0108] The front surface of the first flat plate light source also serves as the imaging screen of the side-view imaging device 8, and the first flat plate light source is parallel to the side of the first optical element coated with a reflective film.

[0109] In this embodiment of the application, the steps of using the aforementioned optical element rapid alignment device combining visual and optical feedback to perform rapid alignment of optical elements include: performing coarse alignment and fine alignment on the plane mirror 24 in sequence, and then performing coarse alignment and fine alignment on the first optical element in sequence.

[0110] Among them, combined Figure 4 In this embodiment, the step of coarsely aligning the plane mirror 24 includes: the controller 11 controls the second rotating platform to move the first optical element away from the second optical element to the beam path of the plane mirror 24, and then controls the laser 14 to emit light; the light emitted by the laser 14 is transmitted through an optical fiber, collimated by the second optical element, and then reflected by the plane mirror 24 onto the imaging screen 25; the controller 11 controls the first rotating platform to align the first optical element with the plane mirror 24 according to the image of the light spot position on the imaging screen 25 collected by the global vision device 4.

[0111] The plane mirror 24 is adjusted in attitude so that the reflected beam of the plane mirror 24 is directed to the center of the end face of the imaging screen 25.

[0112] The step of precisely aligning the planar reflector 24 includes: the controller 11 first controls the first rotating platform to rotate to perform a spiral scan and adjust the tilt angle of the planar reflector 24; simultaneously, it monitors the light intensity value of the reflected beam from the planar reflector 24 detected by the photodetector 12; when the light intensity value of the reflected beam from the planar reflector 24 detected by the photodetector 12 is greater than a set threshold, it controls the first rotating platform to rotate to perform an upward search scan until the light intensity value of the reflected beam from the planar reflector 24 detected by the photodetector 12 reaches its maximum value.

[0113] Among them, reference Figure 5The coarse alignment step for the first optical element includes: the controller 11 controls the second rotating platform to move the first optical element into the beam path from the second optical element to the plane mirror 24, and then controls the laser 14 to emit light; after the light emitted by the laser 14 is transmitted through the optical fiber, the emitted light is collimated by the second optical element, and the collimated emitted light is separated into a reference light and a measurement light by the first optical element. The reference light is reflected by the plane mirror 24 to form a first light spot on the side-view imaging device 8, and the measurement light is incident on the side-view imaging device 8 to form a second light spot; the controller 11 controls the second rotating platform to adjust the attitude of the first optical element according to the light spot position image on the side-view imaging device 8 acquired by the global vision device 4, so that the first light spot and the second light spot are close to coincide. That is to say, when the above alignment device is used for visual feedback coarse alignment of the first optical element, the global vision device 4 acquires the image on the side-view imaging device 8 and performs correction processing to calculate the light spot position information. The controller 11 controls the second rotating platform according to the position information of the light spot on the side-view imaging device 8, adjusts the attitude of the first optical element, and achieves coarse alignment of the first optical element.

[0114] The step of precisely aligning the first optical element includes: the controller 11 controls the second rotating platform to rotate to perform a spiral scan and adjust the tilt angle of the first optical element; simultaneously, the controller monitors the light intensity value of the reflected beam from the plane mirror 24 detected by the photodetector 12, and when the light intensity value of the reflected beam from the plane mirror 24 detected by the photodetector 12 is greater than a set threshold, the controller controls the second rotating platform to rotate to perform an upward search scan until the light intensity value of the reflected beam from the plane mirror 24 detected by the photodetector 12 reaches its maximum value.

[0115] The step of coarsely aligning the first optical element further includes: the controller 11 controls the second rotating platform to adjust the position of the first optical element based on the relative position between the first optical element and the second optical element collected by the first side-viewing vision device 17 and the second side-viewing vision device 19, so that the first optical element and the second optical element are aligned.

[0116] In this embodiment of the application, taking the first optical element as a beam splitter 18 and the second optical element as a gradient refractive index lens 16 as an example, the optical element rapid alignment device combining vision and optical feedback in this embodiment of the application will be described in detail. The side of the beam splitter 18 is coated with a reflective film.

[0117] The alignment principle of the beam splitter 18 and the gradient refractive index lens 16 is as follows: Figure 5As shown. Assuming the beam splitter 18 is an ideal cube, the normal direction of the plane mirror 24 above the gradient refractive index lens 16 is parallel to the axis of the outgoing beam, meaning the plane mirror 24 and the gradient refractive index lens 16 are aligned. According to... Figure 5 In the aligned state, the beam emitted from the gradient refractive index lens 16 is split into two paths by the beam splitter prism 18. One path is reflected sequentially by the semi-reflective and semi-transparent surface and the side-coated reflective surface of the beam splitter prism 18, and then transmitted and reflected again by the semi-reflective and semi-transparent surface; the other path is reflected by the plane mirror 24 and then reflected and transmitted by the semi-reflective and semi-transparent surface. When the two beams reach the end face of the gradient refractive index lens 16 and the side-view imaging device 8, their axes coincide, and the resulting light spots coincide. According to Figure 5 When misaligned, two non-overlapping light spots A and B will be generated on the side-view imaging device 8, and their coordinates can be expressed as:

[0118] A=(C1sinα(sinβ+cosαcosβ),C2(cosβ-sinαsinβ)) (1)

[0119]

[0120] Where α is the roll angle of the beam splitter 18 and β is the pitch angle of the beam splitter 18. C1 and C2 are pre-calibrated constants that depend on the size of the beam splitter 18, the distance between the end face of the gradient refractive index lens 16 and the beam splitter 18, and the distance l between the side-view imaging device 8 and the beam splitter 18.

[0121] Since α and β are very small, sinα can be approximated as α, sinβ as β, and cosα and cosβ as 1. Furthermore, based on the small angle approximation and using Taylor expansion for linear approximation, according to equations (1) and (2), the distance between A and B can be expressed as:

[0122] d=k1α+k2β (3) Where k1 and k2 represent the influence factors of α and β on the distance between A and B, respectively.

[0123] According to equation (3), the distance d between A and B is proportional to the roll angle α and the pitch angle β of the beam splitter 18. By observing and feeding back the control distance d, the control distance d can be made to approach 0, thereby achieving coarse alignment between the beam splitter 18 and the gradient refractive index lens 16.

[0124] Assuming the output beam of the gradient refractive index lens 16 is an ideal Gaussian beam, and its characteristics remain unchanged during propagation, after coarse alignment, the beam reflected from the side-coated reflective surface of the beam splitter 18 enters the gradient refractive index lens 16 at an angle γ after reflection by the beam splitter and propagates into the single-mode fiber. Figure 6As shown. The coupled optical field at the end face of the gradient refractive index lens 16 can be expressed as:

[0125]

[0126] Where w0 is the beam waist radius of the laser emitted from laser 14, and D γ This is due to the offset between the incident and outgoing beams of the gradient refractive index lens 16 caused by the incident angle, which can be expressed as:

[0127]

[0128] In the formula, n0 is the refractive index on the axis of the gradient refractive index lens 16. It is the gradient constant.

[0129] According to equations (4) and (5), the coupled optical field E(γ) at the end face of the gradient refractive index lens 16 is negatively correlated with the incident angle γ of the beam. When γ is 0, the beam splitter prism 18 is aligned with the gradient refractive index lens 16, and the coupled optical field value at the end face of the gradient refractive index lens 16 is the largest, which can be expressed as E0. The coupling efficiency η can be expressed as:

[0130]

[0131] Therefore, the light intensity of the beam coupled into the gradient refractive index lens 16 can be expressed as:

[0132] I=I0η (7) In the formula, I0 is the light intensity in the fully aligned state.

[0133] According to equation (7), when the light intensity I of the beam coupled into the gradient refractive index lens 16 is at its maximum, the coupling efficiency η is at its maximum, and the beam splitter 18 is aligned with the gradient refractive index lens. The light intensity I of the reflected light can be measured and the roll angle and pitch angle can be controlled accordingly to maximize the light intensity I, thereby achieving precise alignment between the beam splitter 18 and the gradient refractive index lens 16.

[0134] Based on the alignment principle described above, the alignment process between the beam splitter 18 and the gradient refractive index lens 16 is as follows: Figure 7 and Figure 8 As shown, the alignment process of the beam splitter 18 is divided into two stages: the alignment of the plane mirror 24 and the alignment of the beam splitter 18. The alignment of the plane mirror 24 and the beam splitter 18 both adopt a combination of visual feedback coarse alignment and optical feedback fine alignment to achieve fast and accurate alignment. The first stage establishes a reference optical path, which provides a reference light point B as an indicator for the visual feedback coarse alignment in the second stage.

[0135] according to Figure 7During coarse alignment of the plane mirror 24, an imaging screen 25 with a centrally located annular hole is fixed at the exit face of the gradient refractive index lens 16, and a corresponding plane mirror 24 is placed above it. A 650nm wavelength red laser is used as the indicator light. The light emitted from the gradient refractive index lens 16 is reflected by the plane mirror 24 and forms a light spot P on the imaging screen 25. The coordinates (x, y, y) of the light spot P in the planar coordinate system can be obtained through the vision system. p ,y p Based on the coordinates of the light spot P in the plane coordinate system, the roll angle ψ and pitch angle θ of the plane mirror 24 can be expressed as follows:

[0136]

[0137] In the formula, l is the distance from the exit end face of the gradient refractive index lens 16 to the plane mirror 24.

[0138] The tilt angle of the plane mirror 24 is adjusted according to the calculation results so that its reflected beam points to the center of the end face of the gradient refractive index lens 16, thereby achieving coarse alignment of the plane mirror 24 based on visual feedback.

[0139] During the fine alignment of the plane mirror 24, the adjustment amount is calculated using a search algorithm based on the detected light intensity I of the reflected beam from the plane mirror 24, and the two tilt angles of the plane mirror 24 are adjusted to maximize I. At this time, the tilt angle γ between the reflected beam and the gradient refractive index lens 16 is 0, thus achieving fine alignment of the plane mirror 24.

[0140] To ensure a fast search speed and obtain the global optimum, a spiral gradient ascent search method is used for precise timing, such as... Figure 9 and Figure 10 As shown. An Archimedean spiral scan is performed starting from the tilt angle (α0, β0) after coarse alignment. The tilt angle during the scan can be expressed as...

[0141]

[0142] Where k is a parameter controlling the spacing between the spirals, determining the amount by which the radius increases for each unit increase in the spiral angle. ω is the angular velocity of the spiral scan, and t is time.

[0143] When the light intensity exceeds a set threshold, the scanning mode switches to gradient ascent scanning. At this time, the tilt angle during scanning can be expressed as:

[0144]

[0145] In the formula, t represents the number of iterations, and η represents the gradient ascent learning rate. This is the gradient ascent step size. The light intensity gradient can be expressed as:

[0146]

[0147] in, Let σ be the coordinate of the maximum light intensity, and σ be a constant.

[0148] The position is updated along the gradient incline direction. The scanning stops when the gradient incline step size is less than the preset step size. At this time, the incident light power at the end face of the gradient refractive index lens 16 reaches the maximum value, and the reference principal optical axis is established.

[0149] During coarse alignment of the beam splitter 18, the distance d between points A and B formed by the indicator light on the side-view imaging device 8 is measured by the vision system and used as the loss function, such as... Figure 4 As shown. Based on the gradient descent algorithm, the two tilt angles of the beam splitter 18 are iteratively adjusted to deflect both beams simultaneously and reduce d until the gradient descent distance is less than the preset minimum step size. At this point, points A and B approach coincidence, and d approaches 0, achieving coarse alignment based on visual feedback. During fine alignment of the beam splitter 18, to avoid interference between the reflected beam from the plane mirror 24 and the reflected beam from the coated reflective surface on the upper side of the beam splitter 18, which would affect the detection of the reflected beam power during alignment, a light-absorbing element 26 is used to cut off the optical path between the gradient refractive index lens 16 and the plane mirror 24, as shown. Figure 8 As shown. Similarly, the intensity of the reflected light received by the optical fiber is read, and the spiral gradient ascending search algorithm is used to control the deflection of the beam splitter 18 to find the orientation with the maximum reflected light intensity. According to equation (7), the deflection angle between the beam splitter 18 and the gradient refractive index lens 16 is close to 0 at this time, achieving precise alignment.

[0150] In this embodiment, the clamping principle of the beam splitter 18 is as follows: Figure 11 As shown. To ensure that the optical paths in the three orthogonal directions are not affected and to facilitate visual and optical feedback during the alignment process, the clamp 27 clamps the beam splitter 18 at a 45° angle. The clamping mechanism 271 of the clamp 27 includes two elastic plates made of different metal materials, with electrically heated parts attached to the ends of the elastic plates. A force sensor 272 is integrated at the end of the clamp 27, which can measure the assembly force when the beam splitter 18 contacts the gradient refractive index lens 16, facilitating force feedback control. In addition, the clamping mechanism 271 and the base 10 are connected by magnetic attraction, which facilitates the separation of the clamping mechanism 271 to grip the beam splitter 18 to be assembled.

[0151] During clamping, the clamping force F is generated through the elastic deformation of the elastic plate of the jaw 271, which can be expressed as:

[0152]

[0153] Where E is the equivalent elastic modulus of the elastic plate, w is the width of the elastic plate, h is the thickness of the elastic plate, l is the length from the front end of the clamp to the fixed position, i.e. the effective length, and δ is the difference between the object size and the distance between the clamp, i.e. the deflection of the clamp caused by the object's compression.

[0154] During release, the electric heating element heats the bimetallic strip, causing it to bend, widen the gap, and open the jaws. When the displacement Δd at the tip of the jaws exceeds δ, the clamping force of the gripper 27 on the beam splitter 18 is zero, achieving precise release during assembly. Δd can be expressed as...

[0155]

[0156] In the formula, k is the geometric amplification factor of the cross-clamp, which is determined by the clamp angle and lever structure, and α A and α B These are the coefficients of thermal expansion between different layers of the double-elastic plate.

[0157] Reference Figure 19 In this embodiment, the clamp 27 specifically includes: a clamping mechanism 271, a force sensor 272, a first base 273, an electric heating element 274, and a magnetic connector 275; the first base 273 is mounted on the second rotating platform and follows the second rotating platform to perform multi-dimensional position changes; one end of the force sensor 272 is detachably connected to the second rotating platform, and the other end is detachably connected to the magnetic connector 275; after the clamping mechanism 271 clamps the beam splitter 18, it is magnetically attracted to the magnetic connector 275; the electric heating element 274 is mounted on the clamping mechanism 271; after the clamping mechanism 271 clamps the beam splitter 18, it is magnetically attracted to the magnetic connector 275. The electric heating element 274 is mounted on the clamping mechanism 271. Magnetic connectors 275 with different thicknesses are replaced according to the thickness of the beam splitter 18 to ensure that the geometric center of the beam splitter 18 held by the clamping mechanism 271 is always located at the rotation center of the second rotating platform. After the beam splitter 18 is fixed to the gradient refractive index lens 16, the clamping mechanism 271 releases the beam splitter 18 under the action of the electric heating element 274. The sensitive axis of the force sensor 272 is parallel to the assembly axis 32 of the beam splitter 18 and the gradient refractive index lens 16 to measure the assembly force generated when the beam splitter 18 is assembled on the gradient refractive index lens 16.

[0158] The clamping mechanism 271 of the clamp 27 includes two elastic plates made of bimetallic materials. The bimetallic material is a composite material made of two metals (or alloys) with different coefficients of thermal expansion. Because the two metals have different coefficients of thermal expansion, they will expand or contract at different rates when the temperature changes, thereby producing bending or deformation.

[0159] When the electric heating element 274 is installed on the inner wall of the first and second elastic plates made of bimetallic material and heated by electricity, the heat generated by the electric heating element 274 will raise the temperature of the bimetallic material; uneven expansion will cause the bimetallic material plates to bend and deform during heating. Specifically, if the metal layer with a smaller coefficient of thermal expansion is located on the inner side (i.e., the side closer to the electric heating element 274), then as the temperature rises, the expansion of the outer metal layer will be more significant than that of the inner metal layer, thereby causing the first and second elastic plates to bend inwards respectively, that is, the first and second elastic plates open, realizing the release of the beam splitter prism 18.

[0160] In this embodiment, laser 14 generates a laser beam that enters the first port of circulator 13, exits from the second port of circulator 13 and enters an optical fiber, and the reflected beam exits from the third port of circulator 13 and enters photodetector 12. The photodetector 12 has a photosensitive surface diameter of, for example, 1 mm, an operating wavelength of 800-1700 nm, a peak response wavelength of 1550 nm, and a responsivity of 0.9 mA / mW. A planar reflector 24 is mounted at the rotation center of the first rotating platform. This planar reflector 24 has a reflection efficiency of up to 95% for 1550 nm wavelength laser light, effectively reducing beam transmission loss.

[0161] The first rotating platform is composed of a first pitch turntable 1 and a first yaw turntable 2 connected in series. During installation, the first yaw turntable 2 is fixed on the first pitch turntable 1, and the rotation center of the first pitch turntable 1 is ensured to coincide with the yaw center of the first yaw turntable 2.

[0162] The clamp 27, which holds the first optical element, integrates a force-sensing clamp 27 and a five-axis displacement stage. The five-axis displacement stage is composed of a dual-axis XY-axis guide rail, a single-axis guide rail rotary table, and a tilting table connected in series. The rotation centers of the rotary table and the tilting table coincide with the tilting center. The clamp 27 is fixed to the upper left corner of the tilting table via the base 10, so that when the beam splitter prism 18 is clamped, its body center rotates with the displacement stage and the tilting center is coaxial.

[0163] To verify the effectiveness of the proposed rapid alignment method for optical elements provided in the embodiments of this application, experiments were conducted.

[0164] During the coarse alignment of the plane mirror 24, the images acquired by the global camera are as follows: Figure 12 and Figure 13 As shown. According to Figure 12Before alignment, the spot of the reflected beam from the plane mirror 24 on the target surface of the fixture 9 is located to the upper right of the center point in the figure. In LabVIEW, the target area is extracted from the image and corrected using a visual measurement algorithm to obtain the coordinates of the spot in the target coordinate system. The roll angle and pitch angle adjustment of the plane mirror 24 are calculated according to equations (8) and (9). The two-axis micro-displacement stage is driven to deflect, so that the reflected beam points to the center of the target surface, thus achieving coarse alignment of the plane mirror 24. Figure 13 As shown.

[0165] During the pre-positioning process of the beam splitter 18, the images acquired by the first side-viewing vision device 17 and the second side-viewing vision device 19 are as follows: Figure 14 and Figure 15 As shown. Figure 14 and Figure 15 The images shown are from the direction perpendicular to the beam-splitting surface of the beam-splitting prism 18 and from the direction facing the beam-splitting surface. Using a visual algorithm, edge extraction and image measurement are performed on the contours of the beam-splitting prism 18 and the gradient refractive index lens 16 to obtain the relative pose data between them. Based on this data, a micro-displacement stage is driven to adjust the pose of the beam-splitting prism 18 so that the lower surface of the beam-splitting prism 18 is parallel to the upper surface of the gradient refractive index lens 16, and the mid-plane of the beam-splitting prism 18 in the vertical direction passes through the axis of the gradient refractive index lens 16, thus achieving the pre-positioning of the beam-splitting prism 18.

[0166] During the coarse alignment of beam splitter 18, the images acquired by the global camera are as follows: Figure 16 and Figure 17 As shown. According to Figure 16 At this time, two non-overlapping red light spots, A and B, appear in the side-view imaging device 8. By visually measuring the distance between points A and B, and adjusting the roll angle and pitch angle of the beam splitter 18 accordingly, points A and B are made to overlap, thus completing the coarse alignment of the beam splitter 18. Figure 17 As shown.

[0167] During the fine alignment of beam splitter 18, the curve showing the change of the normalized value of the reflected light intensity with the number of iterations is as follows: Figure 18 As shown. According to Figure 18 During the alignment process, the threshold for the spiral gradient ascent search was set to 0.15 times the maximum light intensity. After 43 iterations of spiral search, the light intensity was found to exceed the threshold, so the gradient ascent search mode was switched to. After another 8 iterations, the point of maximum light intensity was found, achieving 18-fold precision alignment of the beam splitter prism with an alignment angle accuracy of ±0.01°.

[0168] The main contents of the invention have been described in the foregoing specification through embodiments. However, various modifications and changes can be made without departing from the main contents of the invention as set forth in the claims. The drawings in this specification are illustrative and not restrictive. Therefore, the scope of the invention should be determined by the claims and their legally equivalent forms or entities, and not solely by the described embodiments.

Claims

1. A fast optical element alignment device combining visual and optical feedback, characterized in that, The device comprises: a laser, a circulator, a photodetector, a controller, a base; a plane mirror assembled on the base through a first rotating platform; a first optical element assembled on the base through a second rotating platform, the first optical element being arranged below the plane mirror; a second optical element assembled on the base through a clamp, the second optical element being arranged below the first optical element, and the upper surface of the clamp serving as an imaging screen of the reflected light of the plane mirror; a side-view imaging device assembled on the base; a visual feedback device assembled on the base; the output of the laser is connected to the second optical element through the circulator, the other output of the circulator is connected to the photodetector, and the output of the photodetector is connected to the controller; the input of the controller is connected to the visual feedback device, and the output is connected to the first rotating platform and the second rotating platform; the center of the plane mirror coincides with the rotation center of the first rotating platform; the center of the first optical element coincides with the rotation center of the second rotating platform; the rotation center of the first rotating platform, the rotation center of the second rotating platform and the central axis of the clamp are arranged on the same axis; the side-view imaging device is arranged in parallel with the axis.

2. The optical element rapid alignment device with visual and optical feedback combination of claim 1, wherein, The visual feedback device comprises: a first side-view visualizer fixed on the base and arranged in parallel with the side-view imaging device, the axis of the first side-view visualizer being perpendicular to the orthogonal surface of the first optical element and the orthogonal surface of the second optical element, and the field of view of the first side-view visualizer covering the butt joint area of the first optical element and the second optical element; a second side-view visualizer fixed on the base and arranged perpendicular to the side-view imaging device, the field of view of the second side-view visualizer covering the butt joint area of the first optical element and the second optical element; a global visualizer fixed on the base, and the axis of the global visualizer pointing to the upper surface of the clamp and the side-view imaging device; the intersection of the axes between the first side-view visualizer and the second side-view visualizer is located on the axis.

3. The optical element rapid alignment device combined with visual and optical feedback according to claim 2, wherein when the plane mirror is roughly aligned, the controller controls the second rotating platform to move the first optical element away from the second optical element to the light beam path of the plane mirror; the light emitted by the laser is transmitted through an optical fiber, and the emitted light is collimated through the second optical element and then reflected by the plane mirror to the imaging screen; the controller controls the first rotating platform to adjust the posture of the plane mirror according to the light spot position image of the imaging screen collected by the global visualizer, so that the reflected light beam of the plane mirror is directed to the end surface center of the imaging screen. In the coarse alignment of the first optical element, the controller controls the second rotating platform to move the first optical element into the light beam path of the second optical element and the planar mirror; the light emitted by the laser is transmitted through the optical fiber, and the emitted light is collimated through the second optical element; the collimated emitted light is separated into reference light and measurement light by the first optical element; the reference light is reflected by the planar mirror to form a first light spot on the side-view imaging device; and the measurement light is projected to the side-view imaging device to form a second light spot. The controller controls the second rotating platform to adjust the attitude of the first optical element according to the light spot position image of the side-view imaging device collected by the global vision device, so that the first light spot and the second light spot tend to be coincident.

4. The optical element rapid alignment device with visual and optical feedback combination of claim 1, wherein, In the fine alignment of the planar mirror, the controller controls the first rotating platform to rotate to realize spiral scanning, so as to adjust the tilt angle of the planar mirror; at the same time, the light intensity value of the reflected light beam of the planar mirror detected by the photodetector is monitored; when the light intensity value of the reflected light beam of the planar mirror detected by the photodetector is greater than a set threshold value, the first rotating platform is controlled to rotate to realize upward search scanning, until the light intensity value of the reflected light beam of the planar mirror detected by the photodetector reaches a maximum value. In the fine alignment of the first optical element, the controller controls the second rotating platform to rotate to realize spiral scanning, so as to adjust the tilt angle of the first optical element; at the same time, the light intensity value of the reflected light beam of the planar mirror detected by the photodetector is monitored; when the light intensity value of the reflected light beam of the planar mirror detected by the photodetector is greater than a set threshold value, the second rotating platform is controlled to rotate to realize upward search scanning, until the light intensity value of the reflected light beam of the planar mirror detected by the photodetector reaches a maximum value.

5. The optical element rapid alignment device with visual and optical feedback combination of claim 2, wherein, In the coarse alignment of the first optical element, the controller also controls the second rotating platform to adjust the position of the first optical element according to the relative position between the first optical element and the second optical element collected by the first side-view vision device and the second side-view vision device, so that the first optical element and the second optical element are positionally aligned. In the fine alignment of the first optical element, an optical absorption element is arranged between the second optical element and the planar mirror, for cutting off the light path between the second optical element and the planar mirror.

6. The optical element rapid alignment device with visual and optical feedback combination of claim 1, wherein, The clamp comprises a clamp base, a clamp cover plate and a rotating shaft fixing member, The clamp cover plate is rotatably connected with the clamp base through the rotating shaft fixing member; The upper surfaces of the clamp cover plate and the clamp base jointly serve as an imaging screen of the reflected light of the planar mirror; The shaft centers of the clamp cover plate and the clamp base jointly form a groove for fixing the second optical element; The shaft centers of the clamp cover plate and the clamp base jointly form an optical fiber passing groove, which is communicated with the groove. The clamp cover plate and the clamp base are also attached by magnetic attraction.

7. The optical element rapid alignment device with visual and optical feedback combination of claim 1, wherein, The first optical element is a light splitting prism, and the second optical element is a gradient refractive index lens; a side surface of the light splitting prism is coated with a reflective film.

8. The optical element rapid alignment device with visual and optical feedback combination of claim 2, wherein, A first flat light source is arranged on the side-view imaging device, and a center of the first flat light source is located on an axis of the first side-view visualizer. A second flat light source is arranged on the second rotary table, and a center of the second flat light source is located on an axis of the second side-view visualizer. A front surface of the first flat light source simultaneously serves as an imaging screen of the side-view imaging device, and the first flat light source is parallel to the side surface of the first optical element which is coated with a reflective film.

9. A method for fast alignment of optical elements using visual and optical feedback, applied to the device for fast alignment of optical elements using visual and optical feedback according to any one of claims 1 to 8, characterized in that, The method comprises: The plane mirror is sequentially subjected to coarse alignment and fine alignment, and then the first optical element is sequentially subjected to coarse alignment and fine alignment; The step of coarse alignment of the plane mirror comprises: the controller controls the second rotary platform to move the first optical element away from the second optical element to the light beam path of the plane mirror, and then controls the laser to emit light; the light emitted by the laser is transmitted through an optical fiber, and then the emitted light is collimated through the second optical element and reflected to the imaging screen through the plane mirror; the controller controls the first rotary platform to adjust the posture of the plane mirror according to the light spot position image on the imaging screen collected by the global visualizer, so that the reflected light beam of the plane mirror is directed to the end surface center of the imaging screen; The step of fine alignment of the plane mirror comprises: the controller controls the first rotary platform to rotate to realize spiral scanning, so as to adjust the tilt angle of the plane mirror; meanwhile, the light intensity value of the reflected light beam of the plane mirror detected by the photoelectric detector is monitored; when the light intensity value of the reflected light beam of the plane mirror detected by the photoelectric detector is greater than a set threshold value, the first rotary platform is controlled to rotate to realize upward search scanning until the light intensity value of the reflected light beam of the plane mirror detected by the photoelectric detector reaches a maximum value; The step of coarse alignment of the first optical element comprises: the controller controls the second rotary platform to move the first optical element into the light beam path of the second optical element to the plane mirror, and then controls the laser to emit light; the light emitted by the laser is transmitted through an optical fiber, and then the emitted light is collimated through the second optical element, and the collimated emitted light is separated into reference light and measurement light by the first optical element; the reference light is reflected by the plane mirror to form a first light spot on the side-view imaging device, and the measurement light is directed to the side-view imaging device to form a second light spot; the controller controls the second rotary platform to adjust the posture of the first optical element according to the light spot position image on the side-view imaging device collected by the global visualizer, so that the first light spot and the second light spot tend to be coincident. The step of fine aligning the first optical element comprises: the controller controls the second rotating platform to adjust the tilt angle of the first optical element; meanwhile, the light intensity value of the reflected light beam of the plane mirror detected by the photoelectric detector is monitored, and when the light intensity value of the reflected light beam of the plane mirror detected by the photoelectric detector is greater than a set threshold value, the second rotating platform is first controlled to rotate to realize an upward search scan until the light intensity value of the reflected light beam of the plane mirror detected by the photoelectric detector reaches a maximum value.

10. The method of claim 9, wherein, The step of coarse aligning the first optical element further comprises: the controller also controls the first rotating platform to adjust the three-dimensional position of the first optical element according to the relative position between the first optical element and the second optical element collected by the first side-view visualizer and the second side-view visualizer, so that the first optical element and the second optical element are positionally aligned.

Images