Light beam pointing mechanism for controlling parasitic displacement of rotation center of mirror surface

Abstract

The invention relates to a light beam pointing mechanism for controlling parasitic displacement of a rotation center of a mirror surface, and solves the technical problems in the prior art that additional optical path difference is introduced into pointing precision due to emergent light path translation in a deflection movement process of the mirror surface, the structure is relatively complicated, and the assembly difficulty is high. Piezoelectric ceramic is selected as a driving element, an integrated base is manufactured on the basis of an asymmetric crossed reed type flexible hinge and serves as a supporting and guiding mechanism of an optical element, and one-dimensional high-precision deflection of light beams is achieved. The asymmetric crossed reed type flexible hinge is designed as a rotating pivot, so that the parasitic displacement of the deflection center of the flexible hinge reaches the minimum, the deflection center coincides with the rotating center of the mirror surface, translation of an emergent light path is avoided, and the pointing precision of the light beam pointing mechanism is ensured; in addition, a transmission device is designed, and a driving point is arranged at a position on the same plane as the rotating center of the reflector, so that parasitic displacement is reduced.

Description

Technical Field

[0001] This invention relates to a mirror deflection device in optical precision measurement, and more specifically to a beam pointing mechanism for controlling the parasitic displacement of the mirror rotation center. Background Technology

[0002] In precision optical measurement tasks (such as interferometry), precise control of beam pointing is typically required, necessitating the use of beam pointing mechanisms for deflection. However, under the influence of environmental vibrations, temperature variations, and other factors, the rotation center of the mirror in the beam pointing mechanism will experience a minute parasitic displacement. The rotational motion generated by the mirror deflection also leads to a minute parasitic displacement of its mirror rotation center. These parasitic displacements directly affect image quality and system stability. For instance, in gravitational wave detection, to ensure that the remote telescope can receive the beam for inter-satellite laser interferometry, factors such as seasonal changes in the beam's trajectory and inter-satellite laser transmission time must be considered. Therefore, the control precision requirements for the beam pointing mechanism are high, and parasitic displacements must be minimized as much as possible.

[0003] Unlike most measurement tasks that require beam pointing control, the long-arm interferometry for gravitational wave detection needs to control beam jitter at the nanoradian level, placing higher demands on the control precision and stability of the beam pointing mechanism. To achieve this, the mirror in the beam pointing mechanism must achieve an "absolute rotation" motion. That is, throughout the entire deflection adjustment range, the parasitic displacement along the optical path introduced by the mirror's rotational motion must be controlled with picometer-level precision to ensure the stability of beam transmission.

[0004] In existing beam pointing mechanisms, the deflection structure is usually a flexible hinge design, and its deflection center does not coincide with the rotation center of the mirror surface. This can easily cause the output light path to shift, which not only affects the pointing accuracy of the beam pointing mechanism, but also introduces an additional optical path difference (parasitic displacement) to the mirror. In addition, the beam pointing mechanism is usually composed of multiple precision mechanical parts, which makes the system highly complex. The design, manufacturing, processing and assembly of precision mechanical parts are all difficult, and errors may occur in each link, affecting the final control accuracy. Summary of the Invention

[0005] The purpose of this invention is to solve the technical problems in the prior art where the emitted light path will be translated during the deflection motion of the mirror, which will affect the pointing accuracy, cause parasitic displacement of the reflector, and have a relatively complex structure and high assembly difficulty. The invention provides a beam pointing mechanism that controls the parasitic displacement of the mirror rotation center.

[0006] The concept of this invention is to construct an "absolute rotation" motion mechanism using an asymmetric cross-spring flexible hinge, which solves the problem of parasitic displacement introduced by traditional beam pointing mechanisms during beam rotation manipulation; to use an integrated base, avoiding the assembly of multiple precision mechanical parts, reducing system complexity, and lowering design and assembly difficulty; to select piezoelectric ceramics as the driving element, and to use the asymmetric cross-spring flexible hinge as the support and guiding mechanism for the reflector, thereby achieving one-dimensional high-precision deflection of the beam.

[0007] To achieve the above-mentioned objectives and complete the above-mentioned inventive concept, the technical solution provided by this invention is as follows:

[0008] A beam pointing mechanism for controlling the parasitic displacement of the rotation center of a mirror, characterized by:

[0009] Includes an integrated base and a transmission device and load installed within the integrated base;

[0010] The integrated base includes an outer shell and a mounting platform connected to the outer shell via a rotating shaft pivot. The load includes a mirror mount and an optical element mounted on the mirror mount. The mirror mount is mounted on the mounting platform. The optical element is a reflector used to deflect to achieve beam pointing, and the midpoint of the straight line containing its deflection axis is the mirror rotation center.

[0011] The outer shell includes a top plate and a bottom plate, both of which are U-shaped. The two arms of the top plate are respectively connected to the two arms of the bottom plate through a middle plate. The two arms of the top plate and the corresponding arms of the bottom plate, together with the corresponding middle plates, form two grooves. A rotating pivot is provided in each of the two grooves. The top plate and the bottom plate together form the beam pointing window of the optical element.

[0012] The rotating pivot is an asymmetrical cross-spring flexible hinge structure, consisting of two equal-length springs crossing each other. The two springs on one side of the intersection point are the same length and longer than the length on the other side of the intersection point. The portion of the two springs on one side of the intersection point forms the long axis of the rotating pivot, and the portion on the other side forms the short axis of the rotating pivot. The intersection point forms the deflection center of the rotating pivot. The short axes of the two rotating pivots are connected to the corresponding intermediate plates, and the long axes are connected to the two ends of the mounting platform.

[0013] An actuator mounting plate is provided on the side of the top plate near the mounting platform;

[0014] The transmission device includes transmission connectors and piezoelectric ceramic actuators;

[0015] One end of the piezoelectric ceramic actuator is connected to the actuator mounting plate, and the other end is connected to the rear end of the transmission connector to provide power; the front end of the transmission connector is connected to the mounting platform to convert the power of the piezoelectric ceramic actuator into the deflection power of the optical element.

[0016] Furthermore, to avoid translation of the outgoing light path and reduce parasitic displacement, the line connecting the deflection centers of the two rotating pivots passes through the mirror rotation center.

[0017] Furthermore, to reduce parasitic displacement, the transmission connector includes a transmission rod and a transmission plate connected to the rear side of the transmission rod, with the front side of the transmission rod connected to the mounting platform; the top surface of the transmission plate is connected to the other end of the piezoelectric ceramic actuator, and the end face of the other end of the piezoelectric ceramic actuator is at the same horizontal height as the deflection center of the rotating shaft pivot.

[0018] Furthermore, the transmission plate is a claw-shaped component comprising three claw arms, wherein the front ends of the two side claw arms are fixedly connected to the two ends of the transmission rod, the front end of the middle claw arm is fixedly connected to the middle of the transmission rod, and the tail ends of the three claw arms are connected as one piece. A drive groove is provided near the tail end of the middle claw arm, and the other end of the piezoelectric ceramic actuator is set in the drive groove, serving as the power drive end of the piezoelectric ceramic actuator. The end face of the drive end is at the same horizontal height as the deflection center of the rotation axis pivot. The transmission rod is positioned with one face and two pins, and its two ends are fixedly connected to the mounting platform by a bolt. The actuator mounting plate is provided with an external interface corresponding to the tail end of the transmission plate. The external interface is used to install a displacement sensor. The deflection angle of the mirror is obtained by measuring the relative displacement of the tail end of the transmission plate through the displacement sensor, providing closed-loop feedback for the piezoelectric ceramic actuator.

[0019] Furthermore, the spring thickness of the rotating pivot is d∈(0.42, 0.43)mm; the cross angle of the rotating pivot is θ∈(27.20, 27.40)°; and the minor axis length of the rotating pivot is a∈(3.30, 3.50)mm.

[0020] Furthermore, to ensure the deflection effect, the mounting platform includes a mounting ring and two mounting platform arms disposed on both sides of the mounting ring; the mounting platform arms are located in the groove and there is a gap between them and the groove; the long axes of the two rotating pivots are respectively connected to the front side of the corresponding mounting platform arms; the mounting ring is correspondingly disposed with the optical pointing window.

[0021] Furthermore, the side of the mounting platform arm that connects to the long axis of the rotating shaft pivot has an inner arc surface structure.

[0022] Furthermore, the integrated base is manufactured using wire EDM, in which the spring thickness d error is ±0.013mm, the cross angle θ error is ±1°, and the minor axis length a error is ±0.03mm.

[0023] Furthermore, a compliant motion support is used between the lens mount and the optical elements.

[0024] Furthermore, the lens mount is provided with three support blocks evenly distributed around its circumference. The support blocks are compliant mechanisms to ensure the stability of the rotation center of the mirror surface when the temperature changes. The support blocks are provided with lens mount injection holes, and the outer shell is provided with corresponding base injection holes. The optical components are glued and fixed to the lens mount through the support blocks.

[0025] The advantages of this invention compared to the prior art are:

[0026] 1. This invention provides a beam pointing mechanism for controlling the parasitic displacement of the mirror's rotation center. It employs an asymmetric cross-spring flexible hinge as the rotation pivot. Through design adjustments of the spring thickness d, cross angle θ, and minor axis length a (ratio of major to minor axis), the parasitic displacement of the flexible hinge's deflection center is minimized. The resulting beam pointing mechanism achieves a parasitic displacement control accuracy of 1.1 pm within a ±500 μrad deflection range. In comparison, commonly used fast reflectors exhibit a parasitic displacement of 30 μm within a ±500 μrad deflection range; the lead-angle pointing mechanism used in the European Space Agency's Laser Interferometer Space Antenna (LISA) mission exhibits a parasitic displacement of 240 pm at a limiting deflection angle of 412 μrad. Therefore, the beam pointing mechanism provided by this invention introduces almost no parasitic displacement during pointing, essentially achieving "absolute rotation" of the reflector (optical element), greatly reducing the interference of optical path difference variations on beam transmission.

[0027] 2. The beam pointing mechanism provided by the present invention controls the parasitic displacement of the mirror rotation center. Through the design of an asymmetrical cross-spring flexible hinge, the deflection center of the flexible hinge coincides with the mirror rotation center of the reflector, avoiding translation of the outgoing light path and ensuring the pointing accuracy of the beam pointing mechanism.

[0028] 3. The beam pointing mechanism for controlling the parasitic displacement of the mirror rotation center provided by the present invention redesigns the transmission device. Based on the distance between the driving point of the piezoelectric ceramic actuator and the mirror rotation center, as well as the size parameters of the driving device, the driving point is set at a position on the same plane as the mirror rotation center, thereby reducing the parasitic displacement.

[0029] 4. The beam pointing mechanism for controlling the parasitic displacement of the mirror rotation center provided by the present invention is designed with an integrated base manufactured by slow wire EDM, which makes the beam pointing mechanism have fewer parts and a compact structure, and allows for flexible customization of optical component interfaces, which facilitates assembly and debugging. This solves the problems of complex structure and high design difficulty of existing beam pointing mechanisms.

[0030] 5. The beam pointing mechanism for controlling the parasitic displacement of the mirror rotation center provided by this invention relies primarily on the elastic deformation of the weak link of the asymmetric cross-spring flexible hinge for deflection deformation. This completely eliminates mechanical friction and adhesion during movement, allowing the beam pointing mechanism to achieve high-frequency, high-precision, and high-resolution deflection adjustment within the elastic deformation range. Furthermore, since its deflection deformation mainly depends on elastic deformation, there is no special lubrication requirement, completely avoiding additional interference and contamination of the optical system. In addition, the asymmetric cross-spring flexible hinge requires no maintenance and can be used in various extreme environments such as vacuum and high / low temperatures, making it suitable for a wide range of applications. Attached Figure Description

[0031] Figure 1 This is a three-dimensional structural schematic diagram of an embodiment of a beam pointing mechanism for controlling the parasitic displacement of the mirror rotation center according to the present invention;

[0032] Figure 2 This is a schematic diagram of the coordinate system according to an embodiment of the present invention;

[0033] Figure 3 This is a cross-sectional structural schematic diagram of an embodiment of the present invention;

[0034] Figure 4 This is a schematic diagram of the key parameters of the rotating shaft pivot in an embodiment of the present invention;

[0035] Figure 5 This is a three-dimensional structural diagram of the integrated base in an embodiment of the present invention;

[0036] Figure 6 This is an assembly diagram of the integrated base and transmission connector in an embodiment of the present invention;

[0037] Figure 7 This is a three-dimensional structural diagram of an embodiment of the present invention. Figure 1 (Optical components, lens mounts, and piezoelectric ceramic actuators are omitted);

[0038] Figure 8 This is a three-dimensional structural diagram of an embodiment of the present invention. Figure 2 (Optical components and piezoelectric ceramic actuators omitted);

[0039] Figure 9 This is a three-dimensional structural diagram of an embodiment of the present invention. Figure 3 (Piezoelectric ceramic actuator omitted);

[0040] Figure 10 This is a schematic diagram of the parameters of an existing symmetrical cross-spring flexible hinge when it deflects.

[0041] The symbols in the attached image are explained as follows:

[0042] 1-Optical element; 2-Lens mount, 201-Support block; 3-Outer shell, 301-Top plate, 302-Bottom plate, 303-Intermediate plate, 304-Actuator mounting plate; 4-Rotation pivot; 5-Mounting platform, 501-Mounting platform support arm, 502-Mounting ring; 6-Transmission connector, 601-Transmission rod, 602-Transmission plate; 7-Piezoelectric ceramic actuator;

[0043] a-Load; b-Integrated base; c-Transmission device;

[0044] d - spring thickness; θ - cross angle; a - minor axis length; O - origin; θ E -Offset angle; C r - Initial position of the deflection center, T - Offset position of the deflection center; E0 - Initial position of the free end midpoint, E - Offset position of the free end midpoint; n0 - Initial spacing, n E -Offset spacing, d T - Parasitic displacement. Detailed Implementation

[0045] The specific technical solutions in the embodiments of the present invention will be further described below with reference to the accompanying drawings.

[0046] This invention addresses scenarios in the field of optical precision measurement, such as gravitational wave detection, where strict control of parasitic displacement in beam pointing is required. It employs an asymmetric cross-spring flexible hinge to construct a beam pointing mechanism with "absolute rotation" motion, solving the problem of parasitic displacement introduced during the rotation of the beam in existing beam pointing mechanisms. This provides a solution for future high-precision beam pointing control.

[0047] Figures 1-4 A beam pointing mechanism (precision deflection mechanism) for controlling the parasitic displacement of a mirror rotation center, provided in an embodiment of the present invention, includes an integrated base b, a transmission device c, and a load a installed within the integrated base b. The integrated base b is manufactured using a slow wire EDM process and features an asymmetrical cross-spring flexible hinge as a rotational pivot to provide rotational freedom. Simultaneously, the hinge center coincides with the center of the optical element to reduce its parasitic displacement. Specifically:

[0048] Load a:

[0049] The system includes a mirror mount 2 and an optical element 1 (a reflector with a diameter of 25 mm, whose deflection axis is located at the midpoint of the straight line where the mirror rotates) mounted on the mirror mount 2. As the adjustment object of the precision adjustment platform, the mirror mount 2 and the optical element 1 are supported by compliant motion to ensure the surface accuracy of the optical surface. The mirror mount 2 and the integrated base b are connected by bolts.

[0050] The mirror base 2 is provided with three support blocks 201 evenly distributed along the circumference. The support blocks 201 are compliant mechanisms to ensure the stability of the mirror rotation center when the temperature changes. The support blocks 201 are provided with mirror base glue injection holes. The optical element 1 is glued and fixed to the mirror base 2 through the support blocks 201.

[0051] Integrated base b:

[0052] refer to Figure 5 It includes an outer casing 3 and a mounting platform 5 connected to the outer casing 3 via a rotating pivot 4;

[0053] Mounting platform 5 includes mounting ring 502 and two mounting platform arms 501 disposed on both sides of mounting ring 502; the side of mounting platform arm 501 connected to the rotating shaft pivot 4 has an inner arc surface structure.

[0054] The outer casing 3 includes a top plate 301 and a bottom plate 302, both of which are U-shaped. Two arms of the top plate 301 are connected to corresponding arms of the bottom plate 302 via an intermediate plate 303. Each arm of the top plate 301 and the corresponding arm of the bottom plate 302, together with the intermediate plate 303, form a groove. A rotating pivot 4 is disposed within each of the two grooves. A mounting platform arm 501 is disposed within the groove, with a gap (1.5 mm) between it and the groove. The top plate 301 and the bottom plate 302 form a beam pointing window for the reflector, and a mounting ring 502 is correspondingly disposed with respect to the optical pointing window. An actuator mounting plate 304 is provided on the side of the top plate 301 near the mounting platform 5. The outer casing 3 has a base injection hole corresponding to the mirror mount injection hole.

[0055] refer to Figure 4 The rotating pivot 4 is an asymmetrical cross-spring flexible hinge structure, consisting of two equal-length springs intersecting. The lengths of the two springs on one side of the intersection are the same and greater than the length on the other side. The portions of the two springs on one side of the intersection form the long axis of the rotating pivot 4, and the portions on the other side form the short axis. The intersection forms the deflection center of the rotating pivot 4, and the line connecting the deflection centers of the two rotating pivots 4 passes through the mirror rotation center of the optical element 1. The short axes of the two rotating pivots 4 are respectively connected to the corresponding intermediate plates 303, and the long axes are respectively connected to the front side of the corresponding mounting platform support arm 501. The short axis is a fixed end, and the long axis and the mounting platform are free ends, driven by the transmission device c to rotate around the deflection center.

[0056] The deflection center of the rotating pivot 4 is the intersection point (cross point) of the center lines of the asymmetrical crossed springs. Its translation along the mirror normal direction during rotation is the parasitic displacement (see reference). Figure 2(i.e., the -Z axis direction). During the one-dimensional deflection of the beam pointing mechanism, the mirror rotation center will undergo translation along the mirror normal, and the deflection center of the rotation axis pivot 4 will also undergo displacement in the same direction. To avoid the parasitic displacements generated by the two occurring in the optical path direction, the mirror rotation center and the deflection center of the rotation axis pivot 4 need to be aligned to minimize parasitic displacement.

[0057] The structural design of the asymmetric cross-spring flexible hinge is as follows:

[0058] Figure 10 A schematic diagram of the parameters for deflection of an existing symmetrical cross-spring flexible hinge, with the mirror normal direction (i.e. Figure 2 In the equation (x-Z axis direction), the positive x-axis direction is defined. The two points connecting the minor axis and the intermediate plate are defined as two points on the y-axis. A rectangular coordinate system xy is constructed, with the straight line containing the deflection center (x-axis) intersecting the fixed end at the origin O. The coordinates of the deflection center are then (x...). T The coordinates of the midpoint of the free end are (x, 0), E y E The offset angle is θ. E .

[0059] The initial position of the deflection center (the intersection of the center lines) is C. r The initial position of the midpoint of the free end is E0, C r The initial distance to E0 is n0; the offset position E of the free end midpoint is intersected by the x-axis along the free end normal, and the intersection point (the offset position of the deflection center) is marked as T. Then the offset distance n E The distance between points T and E is equal to n0, at which point C r The distance to T is the parasitic displacement d. T .

[0060] Parasitic displacement d T The calculation method is as follows:

[0061] According to the Euler-Bernoulli equation

[0062]

[0063] in, For the twist angle, the parameter m is the approximate pure torque acting on the free end, E is the elastic modulus, I is the moment of inertia, and l is the length from the fixed end to the free end.

[0064] Separating the variables and integrating, we obtain

[0065]

[0066] Solve for the free end twist angle

[0067] According to the differential chain rule, and get

[0068]

[0069] Solving for the coordinates of the free endpoints:

[0070]

[0071] From the deflection center C r The change in position at point T characterizes the magnitude of the parasitic displacement.

[0072]

[0073] From the above formula, it can be seen that the parasitic displacement d T It is related to the parameter μ (i.e. the moment of inertia I), and the moment of inertia I depends on the cross-sectional shape of the cross reed, that is, there are three key parameters: reed thickness d, cross angle θ, and minor axis length a (i.e. the ratio of the major axis to the minor axis, with the minor axis length as the variable after fixing the major axis length).

[0074] Three key parameters and parasitic displacement d T The relationship between the three is non-linear, and there is a certain correlation between them. The three need to be designed to minimize parasitic displacement.

[0075] Based on the dimensions of the load a and the integrated base b, the major axis length is set to 6mm. With the spring thickness d and the cross angle θ fixed, the minor axis length a is adjusted from 0 to 6mm (a = 6mm indicates a symmetrical cross spring). At this point, the parasitic displacement d varies within the range of 0 to 6mm. T As 'a' increases, it first decreases and then increases, suggesting the existence of a minimum parasitic displacement. Similarly, the minimum parasitic displacement exists for variations in the spring thickness 'd' within the range of 0.2mm to 0.5mm, and for variations in the cross angle 'θ' within the range of 15° to 45°.

[0076] Furthermore, because the parasitic displacement's sensitivity to the three parameters S is related to S... d >S a >>S θ Taking into account the coupling relationship between the three key parameters, adjustments were made to the three key parameters at the minimum parasitic displacement. Simultaneously considering the dimensions of load a and the integrated base b, the ranges of the three key parameters were designed as follows:

[0077]

[0078] In other embodiments of the present invention, the above three key parameters may also be other ranges of values, specifically designed with reference to the dimensions of load a, integrated base b, transmission device c, and the above principles.

[0079] Transmission device c:

[0080] It includes a transmission connector 6 and a piezoelectric ceramic actuator 7. One end of the piezoelectric ceramic actuator 7 is connected to the actuator mounting plate 304.

[0081] The transmission connector 6 includes a transmission rod 601 and a transmission plate 602 connected to the rear side of the transmission rod 601. The transmission plate 602 is a claw-shaped component with three claw arms. The front ends of the two claw arms are fixedly connected to the two ends of the transmission rod 601, respectively, and the front end of the middle claw arm is fixedly connected to the middle part of the transmission rod 601. The tail ends of the three claw arms are connected as one piece. A drive groove is provided near the tail end of the middle claw arm. The other end of the piezoelectric ceramic actuator 7 is set in the drive groove, serving as the power drive end of the piezoelectric ceramic actuator 7. The end face of the drive end is at the same horizontal height as the deflection center of the rotating shaft pivot 4. The front side of the transmission rod 601 is positioned with one side and two pins to the mounting platform 5. Its two ends are fixedly connected to the mounting platform 5 by a bolt, converting the power of the piezoelectric ceramic actuator 7 into the deflection power of the load a. The actuator mounting plate 304 is provided with an external interface corresponding to the tail end of the transmission plate 602. The external interface is used to install a displacement sensor. The relative displacement of the tail end of the transmission plate 602 is measured by the displacement sensor to obtain the deflection angle of the mirror, providing closed-loop feedback for the piezoelectric ceramic actuator.

[0082] The piezoelectric ceramic actuator 7 provides vertically downward driving displacement, and the transmission connector 6 converts the vertical displacement into rotation of the optical element 1.

[0083] In this embodiment of the invention, the distance from the driving point to the center of mirror rotation is L = 29 mm, then the driving displacement u is related to the mirror rotation angle. The relationship is

[0084]

[0085] The gravitational wave detection requires a mirror deflection range of ±450 μrad for the pointing mechanism. The required driving displacement is calculated using this formula, and the driving stroke of the piezoelectric ceramic actuator is selected as 11 μm to ensure a margin.

[0086] The thickness of the transmission plate 602 is 4mm. Therefore, the driving point is set 2mm away from the upper surface of the transmission rod so that the driving point and the offset center are on the same plane to reduce parasitic displacement.

[0087] In this embodiment of the invention, piezoelectric ceramics are selected as the driving element, and an asymmetric cross-spring flexible hinge is used as the support and guiding mechanism for the reflector. This enables one-dimensional high-precision deflection of the beam with minimal parasitic displacement of the optical element, thereby improving the performance of the optical system.

[0088] refer to Figures 6-9 The usage method of this invention is as follows:

[0089] S1, assembling the mirror mount on the integrated base.

[0090] Connect the corresponding positions of the mirror mount 2 and the integrated base b with bolts. Ensure that the phase of the mirror mount 2 is such that the glue injection hole of the mirror mount is coaxial with the glue injection hole of the base, facilitating glue injection. During the slow wire EDM process, special attention must be paid to the machining accuracy of the key parameters of the rotating pivot 4 on the integrated base b. Since the sensitivity of each key parameter to parasitic displacement varies, it is necessary to ensure that the spring thickness d error is ±0.013mm, the cross angle θ error is ±1°, and the minor axis length a error is ±0.03mm.

[0091] S2, Assemble optical components

[0092] Place optical element 1 into lens mount 2, ensuring its accurate placement to guarantee precise alignment of the optical path. Then, secure it with epoxy adhesive, which is injected through the three injection holes of the integrated base b and lens mount 2. Ensure even application of the epoxy adhesive to guarantee a secure and stable bond.

[0093] S3, Assemble the transmission device

[0094] The piezoelectric ceramic actuator 7 is glued to the corresponding position of the transmission connector 6. The transmission device consisting of the piezoelectric ceramic actuator 7 and the transmission connector 6 is then installed on the integrated base b. The transmission connector 6 is connected to the integrated base b with bolts. The corresponding surface of the integrated base b and two locating pins are used to precisely position the actuator on one side. The other end of the piezoelectric ceramic actuator 7 is bolted to the actuator mounting plate 304 on the integrated base b. Ensure that the axis of the piezoelectric ceramic actuator 7 is perpendicular to the connecting plane of the transmission plate 602, and that the connection between the transmission rod 601 and the integrated base b is secure. During connection, ensure that the bolts are tightened appropriately to prevent loosening or detachment during assembly, thus ensuring the stability and reliability of the entire beam pointing mechanism.

[0095] S4, Install beam pointing mechanism

[0096] The beam pointing mechanism provided in this embodiment of the invention is installed in the required optical path. When light enters the mirror, the piezoelectric ceramic drive transmission connector is controlled to drive the integrated base b and the mirror base 2 to deflect one dimension, thereby realizing the optical element 1 (reflector) to complete the required angle deflection and complete the precise pointing of the light. At the same time, no change in optical path perpendicular to the mirror is introduced during the deflection process.

[0097] S5, Commissioning and Calibration

[0098] The optical system of the beam pointing mechanism was debugged and calibrated to ensure its accuracy met the target requirements. By applying different control signals to the piezoelectric ceramic actuator 7, the angular deflection and parasitic displacement of the optical element 1 were verified to meet the design requirements. The deflection angle was then finely adjusted to ensure accurate beam pointing and optimal performance of the optical system.

[0099] S6, Inspection and Maintenance

[0100] In practical applications, it is necessary to regularly inspect and maintain all components of the mechanism, especially the piezoelectric ceramic actuator 7 and the transmission device c, to ensure that they are in good working order in order to guarantee the long-term stable and reliable operation of the mechanism.

[0101] The above description is merely one embodiment of the present invention and is not intended to limit the scope of protection of the present invention. Any equivalent structural transformations made based on the description and drawings of the present invention, or direct or indirect applications in other related technical fields, are included within the scope of patent protection of the present invention.

Claims

1. A beam pointing mechanism for controlling the parasitic displacement of the rotation center of a mirror, characterized in that: It includes an integrated base (b) and a transmission device (c) and a load (a) installed within the integrated base (b); The integrated base (b) includes an outer shell (3) and a mounting platform (5) connected to the outer shell (3) via a rotating pivot (4). The load (a) includes a mirror mount (2) and an optical element (1) mounted on the mirror mount (2). The mirror mount (2) is mounted on the mounting platform (5). The optical element (1) is a reflector used to deflect to achieve beam pointing, and the midpoint of the straight line where its deflection axis is located is the mirror rotation center. The outer shell (3) includes a top plate (301) and a bottom plate (302). Both the top plate (301) and the bottom plate (302) are U-shaped. The two arms of the top plate (301) are respectively connected to the two arms of the bottom plate (302) through the middle plate (303). The two arms of the top plate (301) and the corresponding arms of the bottom plate (302) and the corresponding middle plate (303) form two grooves. A rotating pivot (4) is provided in each of the two grooves. The top plate (301) and the bottom plate (302) form the beam pointing window of the optical element (1). The rotating pivot (4) is an asymmetrical cross-spring flexible hinge structure, which is composed of two springs of equal length crossing each other. The two springs are of the same length on one side of the intersection point and are longer than the length on the other side of the intersection point. The part of the two springs on one side of the intersection point forms the long axis of the rotating pivot (4), and the part on the other side forms the short axis of the rotating pivot (4). The intersection point forms the deflection center of the rotating pivot (4). The short axes of the two rotating pivots (4) are respectively connected to the corresponding intermediate plates (303), and the long axes are respectively connected to the two ends of the mounting platform (5). An actuator mounting plate (304) is provided on the side of the top plate (301) near the mounting platform (5); The transmission device (c) includes a transmission connector (6) and a piezoelectric ceramic actuator (7); One end of the piezoelectric ceramic actuator (7) is connected to the actuator mounting plate (304), and the other end is connected to the rear end of the transmission connector (6) to provide power; the front end of the transmission connector (6) is connected to the mounting platform (5) to convert the power of the piezoelectric ceramic actuator (7) into the deflection power of the optical element (1).

2. The beam pointing mechanism for controlling the parasitic displacement of the mirror rotation center according to claim 1, characterized in that: The line connecting the deflection centers of the two said rotation pivots (4) passes through the mirror rotation center of the mirror.

3. The beam pointing mechanism for controlling the parasitic displacement of the mirror rotation center according to claim 2, characterized in that: The transmission connector (6) includes a transmission rod (601) and a transmission plate (602) connected to the rear side of the transmission rod (601). The front side of the transmission rod (601) is connected to the mounting platform (5). The top surface of the transmission plate (602) is connected to the other end of the piezoelectric ceramic actuator (7). The end face of the other end of the piezoelectric ceramic actuator (7) is at the same horizontal height as the deflection center of the rotating pivot (4).

4. The beam pointing mechanism for controlling the parasitic displacement of the mirror rotation center according to claim 3, characterized in that: The transmission plate (602) is a claw-shaped component including three claw arms. The front ends of the two claw arms are fixedly connected to the two ends of the transmission rod (601), the front end of the middle claw arm is fixedly connected to the middle part of the transmission rod (601), the tail ends of the three claw arms are connected as one piece, and a drive groove is provided near the tail end of the middle claw arm. The other end of the piezoelectric ceramic actuator (7) is set in the drive groove as the power drive end of the piezoelectric ceramic actuator (7). The end face of the drive end is at the same horizontal height as the deflection center of the rotating shaft pivot (4). The transmission rod (601) is positioned with one side and two pins on the mounting platform (5), and its two ends are fixedly connected to the mounting platform (5) by a bolt; the actuator mounting plate (304) is provided with an external interface corresponding to the tail end of the transmission plate (602).

5. A beam pointing mechanism for controlling the parasitic displacement of the mirror rotation center according to any one of claims 1-4, characterized in that: The thickness of the spring in the rotating pivot (4) is d∈(0.42, 0.43)mm; The intersection angle θ of the pivot (4) is (27.20, 27.40)°; The minor axis length a∈(3.30,3.50)mm of the pivot (4) is said to be a.

6. A beam pointing mechanism for controlling the parasitic displacement of the mirror rotation center according to claim 5, characterized in that: The mounting platform (5) includes a mounting ring (502) and two mounting platform support arms (501) disposed on both sides of the mounting ring (502); The mounting platform support arm (501) is located in the groove, and there is a gap between it and the groove; The long axes of the two rotating pivots (4) are respectively connected to the front side of the corresponding mounting platform arm (501); the mounting ring (502) is set in correspondence with the optical pointing window.

7. A beam pointing mechanism for controlling the parasitic displacement of the mirror rotation center according to claim 6, characterized in that: The side of the mounting platform arm (501) that connects to the long axis of the rotating shaft pivot (4) has an inner arc surface structure.

8. A beam pointing mechanism for controlling the parasitic displacement of the mirror rotation center according to claim 7, characterized in that: The integrated base (b) is machined by slow wire EDM. In the slow wire EDM process, the spring thickness d error is ±0.013mm, the cross angle θ error is ±1°, and the minor axis length a error is ±0.03mm.

9. A beam pointing mechanism for controlling the parasitic displacement of the mirror rotation center according to claim 1, characterized in that: The mirror mount (2) and the optical element (1) are supported by compliant motion.

10. A beam pointing mechanism for controlling the parasitic displacement of the mirror rotation center according to claim 9, characterized in that: The mirror base (2) is provided with three support blocks (201) evenly distributed along the circumference. The support blocks (201) are compliant mechanisms to ensure the stability of the mirror rotation center when the temperature changes. The support blocks (201) are provided with mirror base glue injection holes, and the outer shell (3) is provided with corresponding base glue injection holes. The optical element (1) is glued and fixed to the mirror base (2) through the support blocks (201).

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