A hollow retroreflector assembly tooling and a hollow retroreflector assembly tooling system comprising the same

Abstract

The application discloses a hollow retroreflector assembling tool and a hollow retroreflector assembling system comprising the same, relates to the technical field of optoelectronic device manufacturing, and comprises a base provided with three reference planes intersecting with each other, three base plates arranged at corresponding positions of the three reference planes respectively, an angle adjusting mechanism arranged between each base plate and the reference plane and comprising three groups of adjusting pieces distributed in a triangular shape and used for independently adjusting the spatial angle of the base plate, and a limiting structure arranged on a bearing surface of the base plate and used for positioning a lens. The assembling system comprises the above tool and an external autocollimation detection unit, an optical path outlet of the autocollimation detection unit faces the lens, a light beam is emitted to the lens after passing through each optical element, a reflected return image is imaged on an image sensor and angle error information is output. The application realizes independent fine adjustment of the angle of the lens and quantitative closed-loop detection through the three-point supporting type angle adjusting mechanism in cooperation with the autocollimation detection unit, and is suitable for batch assembling and adjustment production of high-precision hollow retroreflectors.

Description

Technical Field

[0001] This invention relates to the field of optoelectronic device manufacturing technology, and in particular to a hollow retroreflector assembly fixture and a hollow retroreflector assembly and adjustment system comprising the same. Background Technology

[0002] Hollow retroreflectors (also known as corner reflectors) possess the unique optical characteristic of achieving parallel retroreflection of beams at any incident angle. They can achieve high-precision beam refracting without strict matching of the light source's coaxiality, making them a core component in high-end optoelectronic systems such as laser long-range ranging, space-to-ground communication, photoelectric tracking and detection, precision optical reference calibration, and satellite attitude positioning. Compared to solid corner prisms, hollow retroreflectors use three plane mirrors to form a hollow pyramidal cavity, offering significant advantages such as lightweight structure, low optical transmission loss, and low manufacturing cost for large-aperture applications.

[0003] Currently, the fabrication of hollow retroreflectors in the industry mainly relies on assembly fixtures to position and adjust the angles of the three planar mirrors. Existing assembly fixtures have the following main technical shortcomings: Firstly, the tooling requires extremely high precision, and the assembly accuracy is limited by the tooling itself. In existing technologies, the first type of fixed integral bonding process directly relies on a high-precision solid pyramid as the tooling reference, bonding a square substrate to the three polished sides of the pyramid for positioning, and fine-tuning the vertical angle accuracy by thinning the adhesive. The product accuracy of this type of solution depends entirely on the machining precision of the solid pyramid, placing extremely high demands on the tooling precision. Furthermore, the adhesive becomes thinner and thinner during mixing, making repeated mixing impossible and posing significant operational challenges.

[0004] Secondly, the tooling structure is complex, and the adjustment mechanism is integrated into the product, resulting in poor applicability for mass production. In the second type of hollow retroreflector with replaceable mirrors, the base and adjustment mechanism are used as part of the finished product. The mirror is bonded to the flat mirror frame of the adjustment mechanism with water-soluble white glue, leading to high product costs. Because the adjustment mechanism is retained as a component of the finished product, factors such as changes in ambient temperature or vibration can easily cause the product to shift, deviating from its initial accuracy. This makes it difficult to guarantee stability during transport and makes it unsuitable for commercial mass production.

[0005] Thirdly, the assembly and adjustment device has a complex structure, cumbersome operation, and low production efficiency. The third type of split assembly and adjustment process uses a metal disc mounted on a rotating base. The metal disc has three propulsion slots, and angled metal blocks are fixed in the propulsion slots. An optical alignment frame is mounted on the angled metal blocks. This solution has a complex device structure, high cost, cumbersome operation steps, and long assembly and adjustment time for single parts, which cannot meet the needs of mass production.

[0006] Furthermore, existing assembly fixtures have fundamental limitations in terms of lens angle adjustment methods. Whether using a fixed design relying on a solid pyramidal reference or a split design employing a propulsion groove and an angled metal block, both can only achieve coarse angle adjustments of the lens in a single direction or within a limited range, lacking the ability to independently and precisely adjust the spatial angle of each lens. This makes it difficult to accurately correct the dihedral angle and orthogonality errors between the three reflectors. The internal stress generated by the lenses and adhesive can easily cause mirror deformation, resulting in poor reflectivity and surface quality in the finished product. Currently, many hollow retroreflectors on the market lack sufficient precision to meet high-precision requirements, exhibiting significant reflection errors.

[0007] The above background information is provided only to aid in understanding the concept and technical solution of this invention. It does not necessarily belong to the prior art of this patent application. In the absence of clear evidence that the above information was disclosed on the filing date of this patent application, the above background information should not be used to evaluate the novelty and inventiveness of this application. Summary of the Invention

[0008] The purpose of this invention is to provide a hollow retroreflector assembly fixture and a hollow retroreflector assembly and adjustment system including the fixture, so as to solve the problems existing in the prior art, realize independent and precise adjustment of lens angle and quantitative closed-loop detection, thereby reducing costs, improving assembly and adjustment accuracy and efficiency, and meeting the needs of mass production.

[0009] To achieve the above objectives, the present invention provides the following solution: A hollow retroreflector assembly fixture for positioning and angle adjustment of the plane mirror in the optical reflection assembly of a hollow retroreflector, comprising: A base having three intersecting reference planes; Three base plates are respectively set at positions corresponding to the three reference planes, and each base plate has a bearing surface for supporting one of the plane mirrors; An angle adjustment mechanism is disposed between each of the base plates and the corresponding reference plane, and is used to adjust the spatial angle of each base plate relative to the corresponding reference plane. The angle adjustment mechanism includes three sets of adjustment components, which are disposed between the same base plate and the corresponding reference plane, and the support points of the three sets of adjustment components are distributed in a triangular pattern. And a limiting structure is provided on the bearing surface of each of the base plates for positioning the plane mirror in at least one direction.

[0010] In an exemplary embodiment, the adjusting member is a lead screw, which is threaded to the base. The top end of the lead screw abuts against the back of the base plate, and an adjusting knob is fixedly connected to the end of the lead screw. Rotating the lead screw drives the base plate to move.

[0011] In one exemplary embodiment, a connecting assembly is further included, the connecting assembly including a resilient connector and a positioning pin, each of the base plates being connected to the base via the resilient connector and the positioning pin, the resilient connector being used to provide a preload force to keep the base plate in contact with the angle adjustment mechanism.

[0012] In an exemplary embodiment, the base has light-transmitting holes at three edges. The light-transmitting holes are located at the intersection of the two reference planes on the base, and the axis of the light-transmitting holes points to the mating and intersection area of ​​the two adjacent planar reflectors. The light-transmitting holes are used to allow curing light to pass through the base and illuminate the lens assembly area.

[0013] In an exemplary embodiment, the limiting structure is a limiting stop that protrudes along the edge of the bearing surface, and the limiting stop is used to limit the short side of the plane mirror.

[0014] The present invention also provides a hollow retroreflector assembly and adjustment system, comprising: The aforementioned hollow retroreflector assembly fixture; And an autocollimation detection unit, disposed outside the assembly fixture, with the optical path outlet of the autocollimation detection unit facing the plane mirror supported on the assembly fixture; The autocollimation detection unit includes a light source, a reticle, a beam splitter, a collimating lens, and an image sensor. The light beam emitted by the light source passes through the reticle, the beam splitter, and the collimating lens before exiting onto the plane mirror. After being reflected by the plane mirror, it returns to the image sensor for imaging. The image sensor outputs the assembly angle error information of the plane mirror based on the offset of the acquired crosshair image.

[0015] In one exemplary embodiment, the light source includes a white light source and a laser source, and the white light source and the laser source are switchably connected to the optical path of the autocollimation detection unit.

[0016] In an exemplary embodiment, the system is configured such that: the number of plane mirrors is three, the three plane mirrors are arranged perpendicularly in pairs on the assembly fixture, and the autocollimation detection unit respectively acquires multiple sets of crosshair images of each plane mirror under different reflection sequences, and the convergence and overlap of each set of crosshair images is used as the condition for determining whether the assembly angle error of the plane mirror meets the preset requirements.

[0017] In an exemplary embodiment, the system is configured to calculate the angular deviation α of the plane mirror according to α = 1 / 2·arctan(ΔS / f) based on the offset ΔS of the crosshair image and the focal length f of the collimating lens, where ΔS is the imaging offset of the crosshair image, f is the focal length of the collimating lens, and α is the angular deviation of the plane mirror.

[0018] In an exemplary embodiment, the base of the assembly fixture is provided with a light-transmitting hole, which is located on the base at the position corresponding to the intersection edge of two of the reference planes. The system also includes an ultraviolet light source, which is located below the base. The curing light emitted by the ultraviolet light source is guided through the light-transmitting hole to the mating edge area of ​​the plane reflector.

[0019] The present invention achieves the following technical effects compared to the prior art: 1. Simple tooling structure and low processing cost; independent and precise spatial angle adjustment achieved through three-point support: In this invention, the angle adjustment mechanism includes three sets of adjusting components, with the support points of the three sets of adjusting components distributed in a triangle. These three points define a plane; by adjusting the three sets of adjusting components separately, independent, continuous, and precise adjustment of the spatial angle of the base plate can be achieved, thereby accurately adjusting the attitude of the plane mirror supported on it. This is fundamentally different from existing technologies that rely on high-precision machining benchmarks with solid pyramids (Type 1), or complex structures integrating the adjustment mechanism into the product (Type 2), or unidirectional coarse adjustment methods using propulsion grooves and angled metal blocks (Type 3). This invention does not require extremely high machining precision from the tooling; the tooling structure is simple and low-cost; and the three-point support structure gives each lens independent spatial angle adjustment capability.

[0020] 2. Stress-free lens clamping avoids mirror deformation and ensures surface accuracy: In existing technologies, lenses are fixed to tooling by adhesive bonding or clamping. The stress generated by bonding and clamping can cause mirror deformation, affecting surface quality. In this invention, the plane mirror is placed only on the bearing surface of the base plate and positioned in at least one direction by a limiting structure, achieving positioning without the need for bonding or clamping. This stress-free clamping method fundamentally avoids mirror deformation caused by clamping stress, providing structural assurance for high surface accuracy.

[0021] 3. Independently adjustable three mirrors provide a structural basis for precise correction of dihedral angle errors: The beam retroreflection accuracy of a hollow retroreflector fundamentally depends on the dihedral angle and orthogonality errors between the three plane mirrors. Existing tooling makes it difficult to independently and precisely adjust the angle of each mirror, resulting in inaccurate correction of orthogonality errors. This invention uses three base plates corresponding to three reference planes, each base plate being independently supported by three sets of adjusting components distributed in a triangle. This enables independent adjustment of the spatial angles of the three mirrors, providing a reliable structural basis for precisely correcting the orthogonality errors of the three mirrors and ensuring the retroreflection accuracy of the finished product.

[0022] 4. High assembly and adjustment efficiency, suitable for mass industrial production: The tooling structure of this invention is simple and the operation is intuitive. The lens can be positioned simply by placing it on the bearing surface, without the need for complicated clamping operations. The three-point support angle adjustment mechanism makes the adjustment process continuous and controllable. The overall assembly and adjustment time for a single product can be reduced to about 5 minutes, resulting in high production efficiency and wide applicability to industrial mass production scenarios.

[0023] Other technical solutions disclosed in this invention also have the following technical advantages: 1. The detection datum and assembly datum are naturally unified, eliminating system-level cumulative errors: In this invention, the autocollimation detection unit is located outside the assembly fixture, with its optical path exit facing the plane mirror supported on the assembly fixture. Compared to the traditional mode in the prior art where the autocollimator and assembly fixture are independent and require separate setup and repeated datum alignment during use, the detection optical path of this invention forms a fixed spatial correspondence with the fixture assembly datum, avoiding system-level cumulative errors caused by datum transfer and repeated alignment, and ensuring the authenticity and reliability of the detection data from the system architecture level.

[0024] 2. Visualized closed-loop debugging significantly reduces assembly difficulty: In this invention, the light beam emitted by the light source passes through the reticle, beam splitter, and collimating lens before exiting to the plane mirror. After reflection, it returns to the image sensor for imaging. The image sensor outputs assembly angle error information based on the offset of the crosshair image. This scheme visually presents the lens angle error in the form of a crosshair image. Operators only need to observe the crosshair offset to determine the direction and magnitude of the deviation in real time, achieving closed-loop debugging with "adjustment and measurement simultaneously." Compared to the extensive assembly and adjustment methods in existing technologies that rely on manual experience and lack quantitative methods, this significantly lowers the operational threshold.

[0025] 3. Dual-light source switching design, balancing coarse adjustment efficiency and fine adjustment accuracy: In this invention, the light source includes a white light source and a laser source, which can be switched into the optical path of the autocollimation detection unit. When the initial deviation of the lens is too large and there is no effective crosshair in the field of view, the laser source can be switched first to quickly complete the coarse adjustment positioning due to the high visibility of the light spot; then, the white light source is switched to perform high-precision fine adjustment. The dual-light source design balances the speed of the coarse adjustment stage with the high precision requirements of the fine adjustment stage, effectively shortening the overall assembly and adjustment time of a single product.

[0026] 4. Six sets of crosshair holographic determination for precise quantification of orthogonality error of three-sided mirrors: In this invention, the system is configured to acquire multiple sets of crosshair images of three plane mirrors under different reflection sequences. The convergence and overlap of each set of crosshair images is used as the condition for determining whether the assembly angle error meets the preset requirements. The six sets of crosshair images correspond to the dihedral angle error information between each pair of the three mirrors. The complete convergence and overlap of the six sets of crosshairs is used as the convergence criterion, fundamentally solving the industry pain point of insufficient orthogonality of three-sided mirrors and ensuring that the retroreflection accuracy of the finished product is stably controlled within 5″. At the same time, the system is configured to calculate the lens angle deviation according to α=1 / 2·arctan(ΔS / f) based on the offset ΔS of the crosshair images and the focal length f of the collimating lens, providing a precise mathematical basis for precision adjustment and avoiding blind trial and error.

[0027] 5. The combination of a light-transmitting aperture and an ultraviolet light source enables in-situ curing and avoids secondary displacement: In this invention, a light-transmitting aperture is provided on the base of the assembly fixture. The system also includes an ultraviolet light source located below the base. The curing light is guided through the light-transmitting aperture to the contact edge area of ​​the plane mirror. This design allows the lens to undergo ultraviolet pre-curing directly without movement after angle adjustment, "locking" the lens attitude in its current optimal state. This avoids the displacement and accuracy loss that occurs when transferring the lens from the adjustment fixture to the curing equipment in traditional solutions.

[0028] 6. System-wide synergistic efficiency, achieving a balance between high precision and high efficiency: This invention organically combines assembly tooling with an autocollimation detection unit to form a complete closed-loop system of "mechanical positioning—angle adjustment—real-time detection—in-situ curing". The tooling's three-point support angle adjustment mechanism provides independent and precise lens angle adjustment capabilities, the autocollimation detection unit provides real-time quantitative error feedback, and the light-transmitting aperture works in conjunction with the ultraviolet light source to achieve in-situ curing. The synergistic effect of these three components reduces the overall assembly and adjustment time of a single hollow retroreflector to approximately 5 minutes, and the finished product's retroreflection accuracy is stably controlled within 5″, with a surface accuracy reaching λ / 2. This systematically solves the technical problems of poor accuracy, low efficiency, and difficult operation in traditional solutions. Attached Figure Description

[0029] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0030] Figure 1 A schematic diagram of the hollow retroreflector assembly tooling disclosed in a specific embodiment of the present invention; Figure 2 for Figure 1 Side view; Figure 3 for Figure 1 Schematic diagram of the middle base; Figure 4 for Figure 3 A structural diagram from another angle; Figure 5 for Figure 1 Schematic diagram of the midsole plate; Figure 6 for Figure 1 A cross-sectional view of the connecting component in the middle; Figure 7 for Figure 1 Schematic diagram of the assembly structure with the plane mirror; Figure 8 for Figure 7 Side view; Figure 9 A schematic diagram of the self-collimation detection unit in the hollow retroreflector assembly and adjustment system disclosed in a specific embodiment of the present invention; Among them, 100 is the assembly tooling; 101 is the base; 1011 is the reference plane; 1012 is the fixed connection structure; 1013 is the light-transmitting hole; 102 is the base plate; 1021 is the bearing surface; 103 is the angle adjustment mechanism; 1031 is the adjusting component; 1032 is the adjusting knob; 104 is the limiting structure; 105 is the connecting assembly; 1051 is the elastic connecting component; and 1052 is the positioning pin. 200. Autocollimation detection unit; 201. Light source; 202. Reticle; 203. Beam splitter; 204. Collimating lens; 205. Image sensor; 300. Plane mirror. Detailed Implementation

[0031] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. 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.

[0032] The purpose of this invention is to provide a hollow retroreflector assembly fixture and a hollow retroreflector assembly and adjustment system including the fixture, so as to solve the problems existing in the prior art, realize independent and precise adjustment of lens angle and quantitative closed-loop detection, thereby reducing costs, improving assembly and adjustment accuracy and efficiency, and meeting the needs of mass production.

[0033] To make the above-mentioned objects, features and advantages of the present invention more readily understood, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0034] Example 1: Hollow Reflector Assembly Fixture Please refer to Figures 1 to 8 This embodiment provides a hollow retroreflector assembly fixture 100, including a base 101, three base plates 102, an angle adjustment mechanism 103, and a limiting structure 104.

[0035] The base 101 is CNC machined from a metal material (such as aluminum alloy or stainless steel) and has three intersecting reference planes 1011. The three reference planes 1011 correspond to the mounting positions of the three plane mirrors 300 of the hollow retroreflector, and the dihedral angle between the three reference planes 1011 is theoretically 90°. The bottom of the base 101 has a fixed connection structure 1012 (e.g., threaded mounting holes or locating pin holes) for fixing the assembly fixture 100 to an external support platform (e.g., an optical platform or a dedicated worktable). Light-transmitting holes 1013 are respectively opened at the three edges of the base 101, located at the intersections of the reference planes 101. The axis of the light-transmitting hole 1013 points towards the mating and intersection area of ​​two adjacent plane mirrors 300, allowing curing light (e.g., ultraviolet light) to pass through the base 101 and illuminate the lens assembly area. The specific method of creating the light-transmitting hole 1013 is conventional mechanical drilling or cutting in this field, and will not be described in detail here.

[0036] Three base plates 102 are respectively disposed at positions corresponding to the three reference planes 1011. Each base plate 102 has a bearing surface 1021 for supporting a plane mirror 300. The base plates 102 are also made of metal, and their bearing surfaces 1021 are precision ground to have a high flatness (e.g., flatness better than 0.01 mm) to ensure stable support when the plane mirror 300 is placed on the bearing surface 1021. The surface roughness of the bearing surface 1021 should not be too high to avoid scratching the back of the plane mirror 300; typically, the roughness Ra is controlled to be ≤0.8 μm.

[0037] An angle adjustment mechanism 103 is disposed between each base plate 102 and the corresponding reference plane 1011, and is used to adjust the spatial angle of each base plate 102 relative to the corresponding reference plane 1011. Figure 2 As shown, the angle adjustment mechanism 103 includes three sets of adjustment members 1031. The three sets of adjustment members 1031 are disposed between the same base plate 102 and the corresponding reference plane 1011, and the support points of the three sets of adjustment members 1031 are distributed in a triangular pattern. The three points define a plane. By adjusting the extension amount of the three sets of adjustment members 1031 respectively, the spatial tilt angle of the base plate 102 can be changed, thereby precisely adjusting the attitude of the plane reflector 300 supported on it.

[0038] In this embodiment, the adjusting component 1031 is a precision lead screw, which is threadedly connected to the base 101, with its top end abutting against the back of the base plate 102. An adjusting knob 1032 is fixedly connected to the end of the lead screw. The operator can drive the lead screw forward or backward by rotating the adjusting knob 1032, thereby changing the position of the lead screw's top end and adjusting the spatial angle of the base plate 102. The lead screw's lead directly affects the adjustment accuracy—the smaller the lead, the smaller the linear displacement per unit rotation angle, and the higher the adjustment accuracy. As an optional implementation, the lead screw can be 0.25mm or 0.5mm, which, combined with the scale markings on the adjusting knob 1032, can achieve sub-arcsecond-level angle adjustment resolution. The threaded connection between the lead screw and the base 101 is a conventional threaded transmission structure in the art, and will not be described further here.

[0039] The connecting assembly 105 movably connects each base plate 102 to the base 101. The connecting assembly 105 includes an elastic connector 1051 and positioning pins 1052. Pin mounting holes are provided on the base plate 102, and corresponding pin mounting holes are also provided on the base 101 at corresponding positions. Two positioning pins 1052 are respectively installed in the pin mounting holes of the base plate 102 and the base 101, and hooks at both ends of the elastic connector 1051 (in this embodiment, a tension spring) are respectively hooked onto the two positioning pins 1052. The tension spring provides a preload force to keep the base plate 102 in contact with the top of the lead screw, ensuring that the base plate 102 remains tightly fitted with the tops of the three sets of lead screws during adjustment, eliminating any backlash that may exist in the threaded drive.

[0040] A limiting structure 104 is disposed on the bearing surface 1021 of each base plate 102 and is used to position the plane mirror 300 in at least one direction. The limiting structure 104 is a limiting stop that protrudes along the edge of the bearing surface 1021 and is used to limit the short side of the plane mirror 300. The height of the limiting stop should be lower than the thickness of the plane mirror 300 to avoid interference with subsequent optical detection. In this embodiment, the height of the limiting stop is 1mm to 2mm, and the specific value can be adjusted according to the thickness of the plane mirror 300.

[0041] The following provides a detailed description of how to use the hollow retroreflector assembly fixture 100 provided in this embodiment.

[0042] First, the assembly fixture 100 is fixed to the optical platform or a special workbench via the fixed connection structure 1012 at the bottom of the base 101. A thin layer of lubricating grease (such as high-vacuum silicone grease or special optical lubricating grease) is applied to the bearing surface 1021 of the base plate 102. The adsorption properties of the grease are used to improve the adhesion stability between the plane mirror 300 and the bearing surface 1021, effectively preventing the lens from slipping or misaligning during subsequent assembly and debugging stages.

[0043] Then, the pre-treated plane mirror 300 is placed on the bearing surface 1021 of the base plate 102, so that the short side of the plane mirror 300 is in contact with the limiting edge on the bearing surface 1021, completing the initial positioning of the lens. The position of the plane mirror 300 is finely adjusted so that multiple sides of the lens synchronously approach the limiting reference. An alternating stacking assembly mode (i.e., the three lenses are initially positioned in sequence and then finely adjusted step by step) is used to complete the initial bonding. After the initial positioning is completed, the outer surface and side end face of the plane mirror 300 are gently pressed with a dust-free degreasing cotton swab to ensure that the lens is tightly bonded to the bearing surface 1021 of the base plate 102, ensuring that there are no assembly gaps between adjacent lenses and no misalignment of high and low layers. Throughout the assembly process, hard components are strictly prohibited from directly contacting the optical working surface of the lens to prevent the mirror surface from being scratched or damaged.

[0044] After the initial assembly of the lenses, the spatial angle of each lens can be finely adjusted using the angle adjustment mechanism 103. Rotating each adjustment knob 1032 drives the corresponding lead screw forward or backward, changing the spatial tilt angle of the base plate 102 and thus adjusting the attitude of the plane mirror 300 mounted on it. The three sets of lead screws are arranged in a triangle, allowing the base plate 102 to be independently adjusted in both pitch and yaw dimensions, achieving stepless continuous adjustment of the spatial angle.

[0045] After the lens angle is adjusted, the ultraviolet light source is placed below the fixture base 101. The ultraviolet light passes through the light-transmitting hole 1013 on the base 101 and illuminates the lens edge and the pre-set adhesive application area, completing the pre-curing and shaping. The axis of the light-transmitting hole 1013 points to the mating intersection area of ​​two adjacent plane mirrors 300, ensuring that the ultraviolet light can accurately illuminate the adhesive position that needs to be cured. After the pre-curing process is completed, the semi-finished lens is removed and sent to the subsequent process for final curing.

[0046] The hollow retroreflector assembly fixture 100 provided in this embodiment has the following core structural feature: the angle adjustment mechanism 103 includes three sets of adjustment components 1031, and the support points of the three sets of adjustment components 1031 are distributed in a triangular pattern. The geometric principle that three points determine a plane gives this structure complete control over the spatial angle of the base plate with a minimum number of adjustment degrees of freedom (three)—the three adjustment amounts correspond to the rotation of the base plate around two orthogonal axes (pitch axis and yaw axis) and the translation of the base plate relative to the reference plane 1011 (achieved by the synchronous advance and retreat of three sets of lead screws). Compared with the existing technology that uses a propulsion groove and an angled metal block to achieve unidirectional coarse adjustment, the three-point support structure of this embodiment achieves truly independent and fine adjustment of the spatial angle. At the same time, the plane reflector 300 is placed only on the bearing surface 1021 and positioned by the limiting structure 104, and positioning can be completed without gluing or clamping, fundamentally avoiding mirror deformation caused by clamping stress. The 1013 aperture design allows the lens to be fixed in place without moving after the angle adjustment is completed, avoiding lens displacement and precision loss caused by handling and transfer in traditional solutions.

[0047] Those skilled in the art should understand that the lead screw described in the above embodiments is only one specific implementation of the adjusting element 1031. Other adjusting elements capable of achieving linear displacement output (such as precision differential heads, piezoelectric ceramic actuators, etc.) can also replace the lead screw to achieve the purpose of this invention. In addition to tension springs, the elastic connecting element 1051 can also be a compression spring, leaf spring, or other forms of elastic element. In addition to limiting flanges, the limiting structure 104 can also be in the form of locating pins, locating blocks, etc. These equivalent substitutions all fall within the protection scope of this invention.

[0048] Example 2: Hollow Reflector Assembly and Adjustment System The following is in conjunction with the appendix Figure 9 The specific embodiments of the present invention will be described in detail below.

[0049] The hollow retroreflector assembly and adjustment system includes assembly fixture 100 and autocollimation detection unit 200.

[0050] The assembly fixture 100 has the same structure as the hollow retroreflector assembly fixture described in Embodiment 1, including a base 101, three base plates 102, an angle adjustment mechanism 103, a limiting structure 104, and a connecting assembly 105. The base 101 has three intersecting reference planes 1011. The three base plates 102 are respectively positioned at corresponding locations on the three reference planes 1011, and each base plate 102 has a bearing surface 1021 for supporting the plane reflector 300. The angle adjustment mechanism 103 is disposed between each base plate 102 and its corresponding reference plane 1011, and is used to adjust the spatial angle of each base plate 102. The limiting structure 104 is disposed on the bearing surface 1021 of each base plate 102, and is used to position the plane reflector 300 in at least one direction. The specific structure of the assembly fixture 100, the connection relationships between its components, and its usage have been described in detail in Embodiment 1, and will not be repeated here.

[0051] The autocollimation detection unit 200 is disposed outside the assembly fixture 100, and the optical path outlet of the autocollimation detection unit 200 faces the plane mirror 300 supported on the assembly fixture 100. Figure 9 As shown, the autocollimation detection unit 200 includes a light source 201, a reticle 202, a beam splitter 203, a collimating lens 204, and an image sensor 205.

[0052] The light beam emitted by the light source 201, carrying the reticle pattern information (crosshair pattern) after passing through the reticle 202, is incident on the beam splitter 203. After being reflected by the beam splitter 203, it enters the collimating lens 204, where it is converted into a parallel beam and exits onto the plane mirror 300 mounted on the assembly fixture 100. If the plane mirror 300 is perpendicular to the principal optical axis, the parallel beam will be reflected back along the original optical path, converged by the collimating lens 204, transmitted through the beam splitter 203, and then imaged onto the image sensor 205, forming a crosshair pattern.

[0053] The basic principle of autocollimation detection is as follows: When the plane mirror 30° tilts at a small angle α, the reflected beam will experience an angular shift of 2α, resulting in a lateral shift ΔS in the imaging position. The imaging shift ΔS, the mirror angle α, and the focal length f of the collimating lens satisfy the following relationship: ΔS = f × tan(2α) Therefore, we can conclude that: α = 1 / 2 × arctan(ΔS / f) As can be seen from the above formula, the detection accuracy of the autocollimation detection unit 200 depends on the focal length of the collimating lens 204 and the single-pixel size of the image sensor (i.e., the smallest recognizable offset). The longer the focal length and the smaller the pixel size, the higher the detection accuracy. As an optional implementation, the focal length of the collimating lens 204 can be 300mm to 500mm, and the image sensor 205 can be a CMOS industrial camera with a resolution of not less than 1280×1024 and a pixel size not greater than 5.2μm. The selection of the above optical components and image sensor are all conventional techniques in this field, and those skilled in the art can make reasonable selections based on the required detection accuracy.

[0054] In this embodiment, the light source 201 includes a white light source and a laser source, which are switchably connected to the optical path of the autocollimation detection unit 200. The white light source is used to provide clear crosshair imaging during the fine-tuning stage, while the laser source is used to provide highly visible spot indication during the coarse-tuning stage. The light source switching can be achieved through a movable reflector or a switchable beam splitter disposed in the optical path. The specific switching method is a conventional optical design in the art and will not be described in detail here.

[0055] When the hollow retroreflector consists of three perpendicular plane mirrors 300, the light beam, after entering the hollow retroreflector, will pass through the three reflecting surfaces sequentially before being reflected back and output. Depending on the different reflection sequences (i.e., different arrangements of the three reflecting surfaces the beam passes through), the beam has six different reflection paths, corresponding to the six reflection sequences of the three mirrors (1-2-3, 1-3-2, 2-1-3, 2-3-1, 3-1-2, 3-2-1). Therefore, the image sensor will acquire a maximum of six sets of crosshair images. The relative offset distance of each set of crosshair images directly characterizes the dihedral angle error between each pair of the three plane mirrors 300. Specifically, the offset of a certain set of crosshair images corresponds to the angular deviation between a certain pair of mirrors, and the convergence and overlap of the six sets of crosshair images comprehensively reflects the overall orthogonality accuracy of the three mirrors.

[0056] The following provides a detailed description of how to use the hollow retroreflector assembly and adjustment system provided in this embodiment.

[0057] The first step is lens pretreatment. The optical lenses undergo cleaning and stress-relief annealing to ensure the optical working surfaces are clean and free of impurities and that the internal structure is stable, thus preventing quality problems caused by contaminants or residual stress during subsequent assembly and use. Lens cleaning and stress-relief annealing are standard techniques in this field and will not be elaborated upon here.

[0058] The second step is pre-application and positioning. The assembly-specific optical adhesive (such as UV-curable optical adhesive) should be allowed to warm to room temperature before use. Please refer to [link / reference]. Figure 7and Figure 8 The plane mirror 300 is a rectangle with varying lengths and widths. During assembly, the side that contacts the reflective surface of the adjacent plane mirror 300 is longer (the long side), while the side that contacts the tooling's limiting edge is shorter (the short side). A medical precision dispensing syringe is used to dispense a precise amount of adhesive onto the long side of the lens near the reflective surface. The dispensing process must ensure uniform adhesive distribution and strictly control the amount of adhesive used to reduce overflow during subsequent bonding. A 3-5mm blank area is left un-dispensed at the bottom of the lens. A thin layer of lubricating grease is applied to the bearing surface 1021 of the base plate 102. The grease's adsorption properties enhance the lens bonding stability and effectively prevent slippage or misalignment during assembly and adjustment. The short side of the optical lens is then bonded to the limiting edge on the bearing surface 1021 to complete the initial lens positioning. The lens position is then fine-tuned so that multiple sides of the lens simultaneously approach the limiting reference, and an alternating stacking assembly method is used to complete the initial bonding. After the initial positioning is completed, use a dust-free degreased cotton swab to gently press the outer surface and side end of the lens to ensure that the lens fits tightly with the tooling and that there are no assembly gaps or misalignments between adjacent lenses.

[0059] The third step is precision lens adjustment based on autocollimation detection. The autocollimation detection unit 200 is activated, allowing the detection beam to be emitted onto the plane mirror 300 mounted on the assembly fixture 100. If no effective crosshair image is observed in the image sensor's field of view, it indicates that the initial angle deviation of the lens is too large, exceeding the effective range of the autocollimation detection unit 200. At this point, the light source 201 is switched to a laser light source. Based on the distribution of the laser reflected spot on the image sensor, the adjustment knob 1032 of the angle adjustment mechanism 103 is finely adjusted until a uniform white screen appears in the image sensor's field of view (indicating that the laser spot has entered the center region of the field of view). Subsequently, the light source 201 is switched to a white light source. At this time, multiple sets of clearly imaged crosshair images will appear in the image sensor's field of view. Finally, the precision adjustment knobs 1032 on the angle adjustment mechanism 103 are finely adjusted one by one until all crosshair images are completely converged and overlapped, with sharp imaging lines and uniform brightness.

[0060] During the debugging process, based on the offset ΔS of the crosshair image and the focal length f of the collimating lens 204, the angular deviation α of the plane mirror 300 is calculated according to α = 1 / 2 × arctan(ΔS / f), providing a precise quantitative basis for the adjustment operation. Operators can determine the adjustment direction and amount of each adjustment knob 1032 based on the calculated angular deviation value, achieving precise quantitative debugging.

[0061] After a single lens group is debugged, the lens assembly is rotated around its central axis for a full rotation to test its stability. If the position and imaging pattern of the crosshair image remain unchanged, the debugging is considered successful. For mass production scenarios, scrapped lenses can be used in advance to calibrate the equipment's baseline parameters, shortening the setup time for the final product.

[0062] The fourth step is curing and shaping. After the lens is properly adjusted, a UV light source is used to fully cover the lens edges and the pre-defined adhesive application area. By setting a differentiated light source energy gradient and irradiation duration, the pre-curing and shaping of the optical reflection component is completed. During the pre-curing process, the curing light may cause the adhesive to shrink, which may slightly affect the lens orientation. The operator can continuously observe the crosshair image on the image sensor during the pre-curing process. If the crosshair image is found to be shifted, the angle adjustment mechanism 103 can be adjusted immediately for compensation and correction. The UV light source can be placed below the base 101 of the assembly fixture 100. The UV light passes through the light-transmitting hole 1013 on the base 101 and irradiates the lens edges and the pre-defined adhesive application area.

[0063] The hollow retroreflector assembly and adjustment system provided in this embodiment forms a complete closed-loop system of "mechanical positioning - angle adjustment - real-time detection - in-situ solidification" through the organic combination of the assembly fixture 100 and the self-collimation detection unit 200. The three-point support angle adjustment mechanism 103 of the assembly fixture 100 provides independent and precise spatial angle adjustment capabilities for each of the three planar reflectors 300; the self-collimation detection unit 200 provides real-time and quantitative crosshair imaging feedback for the adjustment process; the dual-light source switching design takes into account both the speed of the coarse adjustment stage and the high precision requirements of the fine adjustment stage; the complete convergence and overlap of the six sets of crosshair images serves as the convergence criterion, fundamentally solving the technical problem of insufficient orthogonality of the three reflectors. The synergistic effect of the three components achieves a balance between high precision (retroreflection accuracy < 5″, surface accuracy < λ / 2) and high efficiency (assembly and adjustment time for a single component is approximately 5 minutes).

[0064] Those skilled in the art should understand that the white light source and laser source described in the above embodiments are merely two specific implementations of the light source. In other embodiments, the light source may also be a single-wavelength LED light source or other suitable light source type. In addition to the beam splitting scheme using the beam splitter 203, the self-collimating detection unit 200 may also employ a beam splitting scheme using a polarizing beam splitter prism combined with a quarter-wave plate; this is a conventional alternative design in the art. Besides a CMOS camera, the image sensor may also be a CCD camera or other types of photoelectric image sensors. These equivalent substitutions are all within the scope of protection of this invention.

[0065] Furthermore, without altering the pretreatment and curing processes of this invention, there are other alternative solutions for the optical inspection system in the lens precision adjustment stage, such as white light interferometry systems, laser interferometric collimation systems, and Hartmann wavefront detection systems, all of which can achieve lens angle adjustment and retroreflection performance testing. However, compared to the self-collimation detection scheme of this embodiment, these alternative solutions have disadvantages such as higher equipment costs, more complex debugging logic, and slightly longer setup time.

[0066] In the description of this invention, it should be understood that the terms "longitudinal," "lateral," "center," "axial," "radial," "circumferential," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," and "outer," etc., indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings and are used only for the convenience of describing the invention, and do not imply or require that the device or element referred to have a specific orientation or construction method, and therefore should not be construed as a limitation of the invention. Furthermore, the terms "first," "second," and "third," etc., are only used to distinguish the objects of description and should not be construed as limiting importance or order, and the features defined by such terms may explicitly or implicitly include one or more of those features. Unless otherwise stated, "a plurality of" in the description of this invention refers to two or more.

[0067] The terms "installation," "connection," and "joining" should be interpreted broadly, unless otherwise explicitly defined, to include, but are not limited to, fixed connections, detachable connections, or integrally formed connections; mechanical or electrical connections; direct connections or indirect connections via an intermediate medium; and internal communication between two components. Those skilled in the art can understand their meaning based on the specific technical solution. The fixed connections involved in this invention, unless otherwise stated, include both detachable fixed connections (such as bolt and screw connections) and non-detachable fixed connections (such as riveting and welding), and may also include integral structures achieved through an integral forming process (such as casting) (except where integral forming is clearly impossible).

[0068] Unless otherwise stated, the terms used in any of the technical solutions disclosed in this invention to indicate positional relationships or shapes cover states or shapes that are similar to, close to, or adjacent to them.

[0069] Any component provided by this invention can be assembled from multiple individual components or can be a single component manufactured using a one-piece molding process.

[0070] It should be noted that the structures, proportions, sizes, etc., depicted in the accompanying drawings of this specification are only for the purpose of assisting those skilled in the art in understanding and reading the content disclosed in the specification, and are not intended to limit the conditions under which the present invention can be implemented. Therefore, they have no substantial technical significance. Any modifications to the structure, changes in the proportions, or adjustments to the size, without affecting the effects and objectives that the present invention can produce, should still fall within the scope of the technical content disclosed in the present invention.

[0071] In the embodiments of this application, the same reference numerals are used to denote the same component or part.

[0072] Any adaptive changes made according to actual needs are within the scope of protection of this invention.

[0073] It should be noted that, for those skilled in the art, it is obvious that the present invention is not limited to the details of the exemplary embodiments described above, and that the present invention can be implemented in other specific forms without departing from the spirit or essential characteristics of the invention. Therefore, the embodiments should be considered illustrative and non-limiting in all respects, and the scope of the invention is defined by the appended claims rather than the foregoing description. Thus, all variations falling within the meaning and scope of equivalents of the claims are intended to be included within the present invention. No reference numerals in the claims should be construed as limiting the scope of the claims.

Claims

1. A hollow retroreflector assembly fixture for positioning and angle adjustment of a plane mirror (300) in the optical reflection assembly of a hollow retroreflector, characterized in that, include: The base (101) has three intersecting reference planes (1011). Three base plates (102) are respectively set at the corresponding positions of the three reference planes (1011), and each base plate (102) has a bearing surface (1021) for supporting one of the plane mirrors (300). An angle adjustment mechanism (103) is disposed between each of the base plates (102) and the corresponding reference plane (1011) for adjusting the spatial angle of each base plate (102) relative to the corresponding reference plane (1011); The angle adjustment mechanism (103) includes three sets of adjustment components (1031). The three sets of adjustment components (1031) are disposed between the same base plate (102) and the corresponding reference plane (1011), and the support points of the three sets of adjustment components (1031) are distributed in a triangular pattern. And a limiting structure (104) is provided on the bearing surface (1021) of each of the base plates (102) for positioning the plane mirror (300) in at least one direction.

2. The hollow retroreflector assembly fixture according to claim 1, characterized in that: The adjusting component (1031) is a lead screw, which is threaded to the base (101). The top end of the lead screw abuts against the back of the base plate (102), and the end of the lead screw is fixedly connected to an adjusting knob (1032). The base plate (102) is moved by rotating the lead screw.

3. The hollow retroreflector assembly fixture according to claim 1, characterized in that: It also includes a connecting assembly (105), which includes an elastic connector (1051) and a positioning pin (1052). Each of the base plates (102) is connected to the base (101) through the elastic connector (1051) and the positioning pin (1052). The elastic connector (1051) is used to provide a preload force to keep the base plate (102) in contact with the angle adjustment mechanism (103).

4. The hollow retroreflector assembly fixture according to claim 1, characterized in that: The base (101) has three light-transmitting holes (1013) on its three edges. The light-transmitting holes (1013) are located on the base (101) at the intersection of the two reference planes (1011) and the axis of the light-transmitting holes (1013) points to the mating and intersection area of ​​the two adjacent plane mirrors (300). The light-transmitting holes (1013) are used to allow curing light to pass through the base (101) and irradiate the lens assembly area.

5. The hollow retroreflector assembly fixture according to claim 1, characterized in that: The limiting structure (104) is a limiting stop that protrudes along the edge of the bearing surface (1021) and is used to limit the short side of the plane mirror (300).

6. A hollow retroreflector assembly and adjustment system, characterized in that: include: Hollow retroreflector assembly fixture (100) as described in any one of claims 1 to 5; And an autocollimation detection unit (200) is disposed outside the assembly fixture (100), with the optical path outlet of the autocollimation detection unit (200) facing the plane mirror (300) carried on the assembly fixture (100). The autocollimation detection unit (200) includes a light source (201), a reticle (202), a beam splitter (203), a collimating lens (204), and an image sensor (205). The light beam emitted by the light source (201) passes through the reticle (202), the beam splitter (203), and the collimating lens (204) and is emitted to the plane mirror (300). After being reflected by the plane mirror (300), it returns to the image sensor (205) for imaging. The image sensor (205) outputs the assembly angle error information of the plane mirror (300) based on the offset of the acquired crosshair image.

7. The hollow retroreflector assembly and adjustment system according to claim 6, characterized in that: The light source (201) includes a white light source (201) and a laser source (201), and the white light source (201) and the laser source (201) can be switched into the optical path of the autocollimation detection unit (200).

8. The hollow retroreflector assembly and adjustment system according to claim 6, characterized in that: The system is configured such that: the number of plane mirrors (300) is three, the three plane mirrors (300) are arranged perpendicularly in pairs on the assembly fixture (100), and the autocollimation detection unit (200) respectively collects multiple sets of crosshair images of each plane mirror (300) under different reflection sequences, and the convergence and overlap of each set of crosshair images is used as the condition for determining whether the assembly angle error of the plane mirror (300) meets the preset requirements.

9. The hollow retroreflector assembly and adjustment system according to claim 6, characterized in that: The system is configured to calculate the angular deviation α of the plane mirror (300) according to α=1 / 2·arctan(ΔS / f) based on the offset ΔS of the crosshair image and the focal length f of the collimating lens (204), where ΔS is the imaging offset of the crosshair image, f is the focal length of the collimating lens (204), and α is the angular deviation of the plane mirror (300).

10. The hollow retroreflector assembly and adjustment system according to claim 6, characterized in that: The assembly fixture (100) has a light-transmitting hole (1013) on its base (101). The light-transmitting hole (1013) is located on the base (101) at the position where the two reference planes (1011) intersect. The system also includes an ultraviolet light source (201), which is located below the base (101). The curing light emitted by the ultraviolet light source (201) is guided through the light-transmitting hole (1013) to the mating edge area of ​​the plane mirror (300).

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