Two-dimensional piezoelectric displacement stage

Abstract

The present application relates to piezoelectric displacement stage, specifically to a two-dimensional piezoelectric displacement stage, the overall frame-shaped flat displacement stage unit includes an outer frame stage, the inner frame stage is arranged in the frame domain of the outer frame stage and connected through flexible hinge, the displacement stage unit is arranged in two layers to constitute upper layer displacement stage unit and lower layer displacement stage unit, the upper layer displacement stage unit and the lower layer displacement stage unit are consistent in structure, the piezoelectric driver of the lower layer displacement stage unit drives the lower layer inner frame stage to move along X direction, the inner frame stage of the upper layer displacement stage unit is fixed with the inner frame stage of the lower layer displacement stage unit, and the piezoelectric driver of the upper layer displacement stage unit drives the upper layer outer frame stage to move along Y direction relative to the upper layer inner frame stage.The whole displacement stage unit is composed of two layers in series, which avoids the parasitic displacement caused by the action of the lower layer inner frame stage when the upper layer outer frame stage moves, suppresses the generation of parasitic displacement of the two-dimensional piezoelectric displacement stage, and realizes the displacement demand of low coupling and high precision.

Description

Technical Field

[0001] This invention relates to a piezoelectric displacement stage, and more specifically to a two-dimensional piezoelectric displacement stage. Background Technology

[0002] The two-dimensional flexible hinge nanopositioning platform uses piezoelectric ceramics as the driving source and relies on the elastic deformation of the flexible hinge to achieve two-dimensional nanoscale precision translation in the X and Y directions. It has high resolution and high response characteristics and is widely used in optical precision positioning scenarios such as microscopic observation, semiconductor detection, and micro-nano fabrication.

[0003] The patent document entitled "A Large-Stroke Fast-Response XY Micro-Motion Stage with Dual Displacement Amplification" (Publication No. CN105006254A, hereinafter referred to as Document 1) discloses a technical solution including a base, a motion platform, a top cover, leveling screws, piezoelectric ceramics, a stage, and a capacitive displacement sensor. The base, motion platform, and top cover are fixed with screws, and the piezoelectric ceramics are installed in a displacement amplification mechanism. The stage is placed on a dragging platform, and the first and second piezoelectric ceramics and the third and fourth piezoelectric ceramics are respectively located on adjacent sides of the dragging platform and are connected to it. The dragging platform is pushed in different directions by the first and second piezoelectric ceramics and the third and fourth piezoelectric ceramics, thus realizing the two-dimensional movement of the dragging platform.

[0004] The patent document entitled "A Series Piezoelectric Driven Nanopositioning Platform" (publication number CN109140148A, hereinafter referred to as Document 2) discloses a technical solution including a platform body installed in a base, an XY-axis motion platform installed on the platform body, and a piezoelectric ceramic actuator. The XY-axis motion platform is assembled in the base through X-axis flexible hinges and Y-axis flexible hinges, respectively. The X-axis flexible hinges and Y-axis flexible hinges are connected to the platform body through X-axis spring assemblies and Y-axis spring assemblies, respectively. In this solution, the platform body, the Y-axis moving area, and the X-axis moving area are connected to each other through flexible hinges to form an inner and outer nested fit.

[0005] In the above technical solutions, Reference 1 is a single-plane parallel two-dimensional structure, in which four sets of parallelogram amplification mechanisms in X and Y are all arranged in the same frame layer. The X and Y drive chains are connected to the central stage. When the stage moves in the X direction, it will cause unnecessary parasitic displacement or force in the Y direction, resulting in impure motion and affecting accuracy. This is called the coupling phenomenon. In Reference 2, the platform is a nested series structure in the same plane, with the X-direction moving area nested in the Y-direction moving area. The two are directly connected by flexible hinges. The deformation between layers will affect each other, and there will also be interaxial parasitic displacement. Therefore, the two-dimensional piezoelectric displacement stage in the prior art needs to be improved in suppressing parasitic displacement. In addition, arranging bidirectional displacement and detection mechanisms on the same level requires a larger structural size for the displacement stage. Existing platforms either compress the light aperture in pursuit of compactness, resulting in incompatibility with large-sized samples and transmission light paths; or increase the overall size of the machine in order to expand the light aperture, making it difficult to embed the whole machine into extremely small spaces such as microscope stages and detection chambers. Under limited structural size, it is impossible to meet the design requirements of large stroke and large hollow. Summary of the Invention

[0006] This invention provides a two-dimensional piezoelectric displacement stage that suppresses the generation of parasitic displacement on the platform and achieves the requirements of low coupling and high precision displacement.

[0007] To achieve the above objectives, the technical solution adopted is as follows: a two-dimensional piezoelectric displacement stage, the overall frame-shaped flat displacement stage unit includes an outer frame, an inner frame is arranged within the frame area of ​​the outer frame and the two are connected by a flexible hinge, the central hole of the inner frame constitutes a light-transmitting hole, the piezoelectric actuator drives the inner frame to translate along a straight line, the displacement stage unit is arranged in two layers to form an upper displacement stage unit and a lower displacement stage unit, the upper and lower displacement stage units have the same structure, the piezoelectric actuator of the lower displacement stage unit drives the lower inner frame to translate along the X direction, the inner frame of the upper displacement stage unit is fixedly connected to the inner frame of the lower displacement stage unit, the piezoelectric actuator of the upper displacement stage unit drives the upper outer frame to translate relative to the upper inner frame along the Y direction and the Y direction is perpendicular to the X direction, the executed component is mounted on the upper outer frame, the light transmission direction of the central hole of the inner frame constitutes a light-transmitting hole is perpendicular to the two-dimensional plane containing Y and X.

[0008] Compared with the prior art, the technical advantages of the present invention are as follows: The entire displacement stage unit is composed of two layers connected in series. The upper and lower displacement stage units have the same structure, and the inner frames of the upper and lower displacement stage units form an integral structure. The lower displacement stage unit drives the lower inner frame together with the upper displacement stage unit to perform X-axis translational motion, while the outer frame of the upper displacement stage unit performs Y-axis translational motion independently with the upper inner frame as a reference. This avoids the parasitic displacement caused by the movement of the lower inner frame when the upper outer frame moves, thereby effectively suppressing the generation of parasitic displacement of the two-dimensional piezoelectric displacement stage, achieving the displacement requirements of low coupling and high precision. At the same time, it eliminates the need to integrate bidirectional displacement and detection structures in the same layer, which is beneficial to meet the design requirements of large stroke and large hollow within a limited structural size. Attached Figure Description

[0009] Figure 1 This is a schematic diagram of the overall structure of the present invention;

[0010] Figure 2 A schematic diagram illustrating the state when the load platform is removed;

[0011] Figure 3 This is a schematic diagram of the lower displacement stage unit structure;

[0012] Figure 4 for Figure 3 Enlarged view of part M in the image;

[0013] Figure 5 This is a schematic diagram showing the state when the lever element in the lower displacement stage element is removed.

[0014] Figure 6 This is a schematic diagram of a lever unit;

[0015] Figure 7 This is a schematic diagram of a flexible hinge;

[0016] Figure 8 This is a schematic diagram of the upper displacement stage unit structure. Detailed Implementation

[0017] The following is in conjunction with the appendix Figure 1-8 The present invention will be further described in detail below, including related content:

[0018] A two-dimensional piezoelectric displacement stage, comprising a frame-shaped planar displacement stage unit 10, includes an outer frame 11, an inner frame 12 disposed within the frame area of ​​the outer frame 11 and connected to it by a flexible hinge 13, a central hole of the inner frame 12 forming a light-transmitting hole, and a piezoelectric actuator 14 driving the inner frame 12 to perform a linear translational motion. The displacement stage unit 10 is arranged in two layers, forming an upper displacement stage unit 10a and a lower displacement stage unit 10b. With identical structure, the piezoelectric actuator 14 of the lower displacement stage unit 10b drives the lower inner frame stage 12 to translate along the X direction. The inner frame stage 12 of the upper displacement stage unit 10a is fixedly connected to the inner frame stage 12 of the lower displacement stage unit 10b. The piezoelectric actuator 14 of the upper displacement stage unit 10a drives the upper outer frame stage 11 to translate relative to the upper inner frame stage 12 along the Y direction, with the Y direction perpendicular to the X direction. The executed component is mounted on the upper outer frame stage 11. The light transmission direction of the light transmission hole formed by the central hole of the inner frame stage 12 is perpendicular to the two-dimensional plane containing Y and X.

[0019] It can be understood that the displacement stage unit 10, which has an outer frame 11, an inner frame 12, a flexible hinge 13, and a piezoelectric actuator 14, is arranged in two layers, thus forming an upper displacement stage unit 10a and a lower displacement stage unit 10b with the same structure. They are essentially displacement stage units 10, but for the sake of easy distinction and description, they are defined here as upper displacement stage unit 10a and lower displacement stage unit 10b, respectively.

[0020] The outer frame 11 of the lower displacement stage unit 10b is fixedly connected to the base, and the lower inner frame 12 is considered dynamic relative to the base. The inner frame 12 of the upper displacement stage unit 10a is fixedly connected to the inner frame 12 of the lower displacement stage unit 10b. The outer frame 11 of the upper displacement stage unit 10a is not directly connected to the base or the lower displacement stage unit 10b. Therefore, when the piezoelectric actuator 14 of the lower displacement stage unit 10b drives the lower inner frame 12 to perform X-axis translational movement, the upper displacement stage unit 10a as a whole will perform X-axis translational movement together with the lower inner frame 12, which controls the upper outer frame 11, which serves as the load mounting platform, to perform X-axis translational movement.

[0021] When it is necessary to control the upper outer frame 11, which serves as the load mounting platform, to perform a Y-axis translational movement perpendicular to the X-axis, the inner frame 12 of the upper displacement stage unit 10a is used as a reference, and the inner frame 12 is considered static relative to the upper outer frame 11. The upper piezoelectric actuator 14 drives the upper outer frame 11 to translate in the Y-axis relative to the inner frame 12. Thus, by combining the overall X-axis translation of the upper displacement stage unit 10a and the individual Y-axis translation of the upper outer frame 11, the two-dimensional translational movement of the upper outer frame 11, which serves as the load mounting platform, relative to the base is finally achieved.

[0022] In the above technical solution, the entire displacement stage unit 10 is composed of two layers connected in series. The upper outer frame stage 11 is connected to the upper inner frame stage 12 through a corresponding flexible hinge 13. When the upper outer frame stage 11 moves in the Y direction, the actuation effect produced by the extension and retraction of the upper piezoelectric actuator 14 exists only in the system of the upper displacement stage unit 10a and will not affect the lower displacement stage unit 10b. Therefore, the above technical solution achieves a higher degree of decoupling of the two-dimensional displacement motion of the upper outer frame stage 11, avoiding the parasitic displacement caused by the movement of the lower inner frame stage 12 when the upper outer frame stage 11 moves. This effectively suppresses the generation of parasitic displacement of the two-dimensional piezoelectric displacement stage and achieves the displacement requirements of low coupling and high precision.

[0023] Furthermore, through the aforementioned layered decoupling design, there is no need to integrate bidirectional displacement and detection structures within the same layer. For the side of the single-layer displacement stage unit 10 where no displacement or detection structures are located, the size can be reduced while ensuring the required light transmission area of ​​the central aperture. This facilitates achieving the design requirements of large stroke and large hollow space within limited structural dimensions. It should be noted that the size reduction here mainly refers to reducing the area occupied by the two-dimensional piezoelectric displacement stage on the base, not the vertical height of the two-dimensional piezoelectric displacement stage. In the field of piezoelectric displacement stages, the millimeter-level difference between the overall area occupied on the base and the central light transmission aperture has a significant and undeniable impact on equipment compatibility.

[0024] Since the upper displacement stage unit 10a and the lower displacement stage unit 10b have the same structure, for ease of description, the following description will take the lower displacement stage unit 10b as an example. It should also be understood that the upper displacement stage unit 10a contains the same structure, but the specific motion forms of the outer frame stage 11 and the inner frame stage 12 of the upper displacement stage unit 10a need to be analyzed specifically:

[0025] Furthermore, taking the lower displacement stage element 10b as an example, such as... Figure 3 As shown, the lower displacement stage unit 10b also includes a lever unit 15. The lever unit 15 is disposed within the frame area of ​​the outer frame stage 11 and located on one side of the inner frame stage 12 relative to the outer frame stage 11 in the direction of relative movement. The two ends of the lever unit 15 are connected to the outer frame stage 11 and the inner frame stage 12 respectively through a first flexible hinge piece 151 and a second flexible hinge piece 152. The output end of the piezoelectric actuator 14 located on the outer frame stage 11 is connected to the position of the lever unit 15 adjacent to the first flexible hinge piece 151 through a third flexible hinge piece 153. The third flexible hinge piece 153 is located between the first flexible hinge piece 151 and the second flexible hinge piece 152. When the piezoelectric actuator 14 performs telescopic movement, it drives the lever unit 15 to swing around the position of the first flexible hinge piece 151 and drives the inner frame stage 12 to translate along the X direction.

[0026] In this design, the piezoelectric actuator 14 drives the inner frame 12 to move via the lever unit 15. When the piezoelectric actuator 14 extends or retracts, it drives the lever unit 15 to swing around the position of the first flexible hinge piece 151 and causes the inner frame 12 to translate along the X direction. Since the output end of the piezoelectric actuator 14 is connected to the position of the lever unit 15 near the first flexible hinge piece 151, the lever unit 15 essentially constitutes a displacement amplification mechanism. When the lever unit 15 swings at a small angle at the position of the third flexible hinge piece 153, the lever unit 15 at the position of the second flexible hinge piece 152 can obtain a larger linear displacement, thereby amplifying the stroke of the inner frame 12 and meeting the design requirements of a large stroke.

[0027] It should be noted that the first, second, and third flexible hinge pieces 151, 152, and 153 all possess a certain bending deformation capability, essentially equivalent to flexible hinge 13, satisfying the swing design requirements of lever unit 15. Simultaneously, the bending deformation of the first flexible hinge piece 151 helps reduce the bending and torsional forces transmitted to the piezoelectric actuator 14, effectively protecting it. However, it is important to note that the design principle for this part is to minimize bending stiffness while ensuring a certain output stiffness, thereby guaranteeing the output of the target displacement, while keeping the maximum deformation stress within the material's safe range. Furthermore, when lever unit 15 swings, a significant lateral displacement will occur at its displacement amplification end, i.e. Figure 3 Therefore, the lever unit 15 cannot be rigidly connected to the inner frame 12 in the left-right direction. Instead, the lever unit 15 and the inner frame 12 are connected by the second flexible hinge piece 152. The second flexible hinge piece 152 has the ability to bend and deform. While ensuring the output stiffness, the lateral stiffness is reduced as much as possible, thereby reducing the large lateral parasitic displacement of the inner frame 12 caused by the lateral tension.

[0028] As a preferred solution, combined with Figure 3-6 As shown, the outer frame 11 and the inner frame 12 are generally square, and their opposite side frame rods are parallel to each other. The lever unit 15 is located between the opposite side frame rods of the inner frame 12 and the outer frame 11 in the relative movement direction of the inner frame 12. The outer frame 11 has a mounting groove 111 on the rod surface of the frame rod parallel to the relative movement direction of the inner frame 12, and the groove length direction of the mounting groove 111 is arranged along the rod length direction of the side frame rod. The piezoelectric actuator 14 is located in the mounting groove 111 and its extension direction is parallel to the groove length direction of the mounting groove 111. One end of the lever unit 15 is connected to the frame rod of the outer frame 11 parallel to the relative movement direction of the inner frame 12 through the first flexible hinge piece 151. The other end of the lever unit 15 is connected to the middle position of the adjacent side frame rod of the inner frame 12 perpendicular to its relative movement direction through the second flexible hinge piece 152.

[0029] In this design, a lever unit 15 is positioned on one side of the outer frame 11 along the movement direction of the inner frame 12. A mounting groove 111 for the piezoelectric actuator 14 is provided on the frame rod of the outer frame 11 adjacent to this side. The lever unit 15 and the piezoelectric actuator 14 do not need to be located on the same side of the outer frame 11. This arrangement provides a reasonable placement for the lever unit 15 and the piezoelectric actuator 14, and avoids the problem of integrating the lever unit 15 and the piezoelectric actuator 14 on the same side, which would result in a large integrated volume and require a reduction in the size of the inner frame 12 within limited structural dimensions, thus affecting the size of the central light-transmitting hole. Simultaneously, the mounting groove 111 is hollowed out on the frame rod of the outer frame 11, providing a reasonable installation space for the piezoelectric actuator 14 without increasing the frame rod size.

[0030] In existing technologies, bridge / parallelogram amplification mechanisms are used to amplify the displacement of the mover. However, this requires integrating the piezoelectric actuator 14 and the amplification mechanism on the same side, which greatly increases the overall volume and significantly reduces the hollow light-transmitting area or the space for the mover. In contrast, the lever unit 15 and the piezoelectric actuator 14 provided by this invention are arranged on separate sides. The single-side structure is small in size and does not encroach on the central hollow area, thus meeting the design requirements of large stroke and large hollow area.

[0031] Furthermore, in this embodiment, the piezoelectric actuator 14 is a stack of piezoelectric ceramics, and the mounting groove 111 is disposed on the upper rod surface of the frame rod with the groove opening facing upward. One end of the mounting groove 111 near the lever unit 15 is connected to the inner frame region of the outer frame platform 11 to form an open arrangement. One end of the lever unit 15 away from the inner frame platform 12 extends through the open into the groove cavity of the mounting groove 111 and is connected to the outer side of the groove wall of the mounting groove 111 through the first flexible hinge piece 151.

[0032] Here, the outer frame 11, inner frame 12, flexible hinge 13, and lever unit 15 can be integrally cut and formed. Since the lever unit 15 and inner frame 12 occupy the frame space of the outer frame 11, the mounting slot 111 is arranged with its opening facing upwards, providing operable space for the installation of the piezoelectric ceramic stack. Additionally, as... Figure 5 As shown, the mounting groove 111 has an open end on one side, and the lever unit 15 can extend into the mounting groove 111 through the open end to connect with the piezoelectric ceramic stack.

[0033] Furthermore, a spring 16 is embedded inside the frame rod on the side of the outer frame 11 adjacent to the lever unit 15. The two ends of the spring 16 are connected to the outer frame 11 and the end of the lever unit 15 away from the first flexible hinge piece 151, respectively. The elastic force generated by the extension and retraction of the spring 16 provides a reliable preload and reset force for the lever unit 15. After the driving force of the inner frame 12 is unloaded, the elastic force of the spring 16 can pull the lever unit 15 and the inner frame 12 back to the initial equilibrium position, achieving automatic centering and preventing the inner frame 12 from remaining in an offset state.

[0034] Combination Figure 3 , Figure 4 as well as Figure 6 As shown, the first, second, and third flexible hinge pieces 151, 152, and 153 are all thin plate structures. The end of the second flexible hinge piece 152 away from the inner frame 12 is connected to the end face of the lever unit 15 near the outer frame 11 and forms a U-shaped groove with an opening pointing towards the inner frame 12. As mentioned above, lever unit 15 requires the deformation of the second flexible hinge piece 152 to reduce the lateral parasitic displacement of the inner frame 12. The second flexible hinge piece 152 is located at the displacement amplification end of lever unit 15. The shorter the second flexible hinge piece 152, the greater its bending stiffness and the less likely it is to deform. Therefore, through the design of the second flexible hinge piece 152 in this scheme, the second flexible hinge piece 152 has sufficient plate length to provide effective bending deformation capability. At the same time, since the end of the second flexible hinge piece 152 away from the inner frame 12 is connected to the end face of lever unit 15 near the outer frame 11, the space occupied by lever unit 15 itself in the direction of movement of inner frame 12 is used to integrate the second flexible hinge piece 152. Naturally, there is no need to leave a large space between the lever unit 15 and the opposite side of the inner frame 12 to set the second flexible hinge piece 152. The overall structure has high integration and compactness, achieving the maximum light transmission aperture without increasing the overall machine footprint, perfectly balancing "compactness". With "optical adaptability," a reliable foundation is provided for the design requirements of large stroke and large hollow space of the displacement stage within a limited structural size.

[0035] As a preferred embodiment, the vertical plane passing through the center of the inner frame 12 and parallel to the relative movement direction of the inner frame 12 is taken as the plane of symmetry. The lever unit 15 and the piezoelectric actuator 14 on the lower displacement stage unit 10b are symmetrically arranged in two sets, and all structures on the lower displacement stage unit 10b are symmetrically distributed with respect to the vertical plane.

[0036] In this scheme, the entire lower displacement stage unit 10b is arranged symmetrically with its own central plumb plane. The overall structural stiffness is balanced and the lateral tensile forces on the inner frame stage 12 cancel each other out, suppressing the generation of lateral parasitic displacement and ensuring that the inner frame stage 12 moves along the ideal straight line direction. Taking the lower displacement stage unit 10b as an example, that is, the X direction.

[0037] Furthermore, such as Figure 3 As shown, the flexible hinge 13 is generally U-shaped. Two flexible hinges 13 are connected to the opposite sides of the inner frame 12 on each side of the frame members in the direction of relative movement. The opening direction of the flexible hinge 13 is horizontal, perpendicular to the direction of relative movement of the inner frame 12. One end of the flexible hinge 13 is fixed to the inner frame 12, and the other end is fixed to the outer frame 11. Each flexible hinge 13 is symmetrically arranged with a vertical surface passing through the center of the inner frame 12 and parallel to the direction of relative movement of the inner frame 12 as the symmetrical face. In this design, the shape and opening direction of the flexible hinge 13 are designed to provide support and guidance for the inner frame 12.

[0038] It should be noted that piezoelectric displacement stages are precision micro-displacement motion components, and their stroke is typically controlled within the micrometer range. Therefore, if... Figure 3 As shown, the lever unit 15 is arranged with gaps between its main body and the outer frame 11, inner frame 12 and even the flexible hinge 13 on the same layer, forming a compact structure. The size of these gaps meets the relative displacement requirements of the lever unit 15, the outer frame 11, the inner frame 12 and even the flexible hinge 13.

[0039] As a preferred option, such as Figure 7 As shown, a thickened portion 131 is integrally formed in the middle of the two arms of the flexible hinge 13. The width of the thickened portion 131 in the horizontal direction perpendicular to the opening direction of the flexible hinge 13 is greater than the end width of the side arm of the flexible hinge 13 and the width at the connection position of the two arms. By designing the thickened portion 131 of the flexible hinge 13, local reinforcement is formed, which significantly improves the bending and torsional stiffness of the area without affecting the support and guidance of the inner frame 12. This avoids the inner frame 12 from generating rotational parasitic displacements such as pitch and yaw when the flexible hinge 13 deforms, ensuring the straightness of the movement and effectively improving the mechanical modes of the inner frame 12 in the non-movement direction under load.

[0040] To precisely control the displacement of the inner frame platform 12, a displacement sensor 17 is installed on the inner rod surface of the opposite side of the outer frame platform 11, away from the lever unit 15. The reading head of the displacement sensor 17 is opposite to the adjacent side rod surface of the inner frame platform 12, forming a closed-loop control of the displacement of the inner frame platform 12. In this scheme, the displacement sensor 17 monitors the linear displacement of the inner frame platform 12 relative to the outer frame platform 11, and feeds the displacement data back to the controller to control the relative motion stroke between the inner frame platform 12 and the outer frame platform 11. The closed-loop control system is existing technology, so its specific principle will not be explained in detail here.

[0041] It is hereby declared that the above content is explained using the lower displacement stage unit 10b as an example. The outer frame of the lower displacement stage unit 10b is fixed and the inner frame 12 is not fixed. The upper displacement stage unit 10a has the same structure as the lower displacement stage unit 10b. The relative motion direction between the outer frame 11 and the inner frame 12 of the upper displacement stage unit 10a is Y-direction. When considering the motion change of the upper displacement stage unit 10a, the outer frame 11 of the upper displacement stage unit 10a is not fixed and the inner frame 12 is fixed relative to the inner frame 12 of the lower displacement stage unit 10b. The expansion and contraction of the piezoelectric ceramic stack will cause the outer frame 11 of the upper displacement stage unit 10a to be displaced relative to the inner frame 12 of the upper layer. In essence, it is a "reverse interchange" of force and motion, except that the main body of motion changes from the inner frame 12 to the outer frame 11.

[0042] Combination Figure 1 , Figure 2 As shown, in order to ensure that the inner frame stage 12 holes of the upper and lower displacement stage units 10a and 10b are arranged facing each other, to ensure the continuous passage of the optical path, and to avoid problems such as obstruction of the optical path and reduction of the effective light transmission aperture, the following measures are taken.

[0043] As a preferred embodiment, the upper end face of the outer frame 11 of the upper displacement stage unit 10a and the lower end face of the lower displacement stage unit 10b are both connected to an annular platform 20, and the diameter of the central hole of the platform 20 is greater than or equal to the diameter of the central hole of the inner frame 12. The executed component is installed on the platform 20 on the upper displacement stage unit 10a.

[0044] In this design, a platform 20 is provided on the upper surface of the upper displacement stage unit 10a to provide an installation and bearing position for the executed component. Furthermore, since the upper displacement stage unit 10a and the lower displacement stage unit 10b have identical structures, they can be completely reversed. The original lower displacement stage unit 10b becomes the upper displacement stage unit 10a after being reversed, and the original upper displacement stage unit 10a becomes the lower displacement stage unit 10b after being reversed.

Claims

1. A two-dimensional piezoelectric displacement stage, comprising a frame-shaped planar displacement stage unit (10) including an outer frame stage (11), an inner frame stage (12) disposed within the frame region of the outer frame stage (11) and connected to it by a flexible hinge (13), wherein the central hole of the inner frame stage (12) constitutes a light-transmitting hole, and a piezoelectric actuator (14) drives the inner frame stage (12) to perform translational motion along a straight line, characterized in that: The displacement stage unit (10) is arranged in two layers, forming an upper displacement stage unit (10a) and a lower displacement stage unit (10b). The upper and lower displacement stage units (10a and 10b) have the same structure. The piezoelectric actuator (14) of the lower displacement stage unit (10b) drives the lower inner frame stage (12) to translate along the X direction. The inner frame stage (12) of the upper displacement stage unit (10a) is fixedly connected to the inner frame stage (12) of the lower displacement stage unit (10b). The piezoelectric actuator (14) of the upper displacement stage unit (10a) drives the upper outer frame stage (11) to translate relative to the upper inner frame stage (12) along the Y direction, and the Y direction is perpendicular to the X direction. The executed component is installed on the upper outer frame stage (11). The light transmission direction of the central hole of the inner frame stage (12) is perpendicular to the two-dimensional plane where Y and X are located. The lower displacement stage unit (10b) also includes a lever unit (15). The lever unit (15) is located within the frame area of ​​the outer frame stage (11) and on one side of the inner frame stage (12) and the outer frame stage (11) in the direction of relative movement. The two ends of the lever unit (15) are connected to the outer frame stage (11) and the inner frame stage (12) respectively through a first flexible hinge piece (151) and a second flexible hinge piece (152). The output end of the piezoelectric actuator (14) located on the outer frame stage (11) is connected to the lever unit (15) near the first flexible hinge piece (151) through a third flexible hinge piece (153). The chain piece (153) is located between the first flexible hinge piece (151) and the second flexible hinge piece (152). When the piezoelectric actuator (14) performs telescopic movement, it drives the lever unit (15) to swing around the position of the first flexible hinge piece (151) and drive the inner frame platform (12) to translate along the X direction. The first, second, and third flexible hinge pieces (151, 152, and 153) are all thin plate structures. The end of the second flexible hinge piece (152) away from the inner frame platform (12) is connected to the lever unit (15) rod end face near the outer frame platform (11) and forms a U-shaped groove with an opening pointing towards the inner frame platform (12). With the plumb plane passing through the center of the inner frame (12) and parallel to the relative motion direction of the inner frame (12) as the plane of symmetry, the lever unit (15) and the piezoelectric actuator (14) on the lower displacement stage unit (10b) are arranged symmetrically in two sets, and each structure on the lower displacement stage unit (10b) is symmetrically distributed with respect to the plumb plane.

2. The two-dimensional piezoelectric displacement stage according to claim 1, characterized in that: The outer frame platform (11) and the inner frame platform (12) are generally square, and their opposite side frame rods are parallel to each other. The lever unit (15) is located between the opposite side frame rods of the inner frame platform (12) and the outer frame platform (11) in the relative movement direction of the inner frame platform (12). The outer frame platform (11) has a mounting groove (111) on the rod surface of the frame rod parallel to the relative movement direction of the inner frame platform (12), and the length direction of the mounting groove (111) is arranged along the length direction of the rod of that side frame rod. The piezoelectric drive The actuator (14) is located in the mounting groove (111) and its extension direction is parallel to the groove length direction of the mounting groove (111). One end of the lever unit (15) is connected to the frame rod on the outer frame platform (11) parallel to the relative movement direction of the inner frame platform (12) through the first flexible hinge piece (151). The other end of the lever unit (15) is connected to the middle position of the adjacent side frame rod on the inner frame platform (12) perpendicular to its relative movement direction through the second flexible hinge piece (152).

3. The two-dimensional piezoelectric displacement stage according to claim 2, characterized in that: The piezoelectric actuator (14) is a stack of piezoelectric ceramics. The mounting groove (111) is set on the upper rod surface of the frame rod with the groove opening facing upward. The end of the mounting groove (111) near the lever unit (15) is connected to the inner frame area of ​​the outer frame platform (11) to form an open arrangement. The end of the lever unit (15) away from the inner frame platform (12) extends through the open into the groove cavity of the mounting groove (111) and is connected to the outer side of the groove wall of the mounting groove (111) through the first flexible hinge piece (151).

4. The two-dimensional piezoelectric displacement stage according to claim 2, characterized in that: A spring (16) is embedded in the side frame rod of the outer frame (11) near the lever unit (15). The two ends of the spring (16) are respectively connected to the outer frame (11) and the end of the lever unit (15) away from the first flexible hinge piece (151).

5. The two-dimensional piezoelectric displacement stage according to claim 2, characterized in that: The flexible hinge (13) is U-shaped. Two flexible hinges (13) are connected to the opposite sides of the inner frame (12) in the direction of relative movement. The opening direction of the flexible hinge (13) is horizontal, perpendicular to the direction of relative movement of the inner frame (12). One end of the flexible hinge (13) is fixed to the inner frame (12), and the other end is fixed to the outer frame (11). Each flexible hinge (13) is arranged symmetrically with a plumb surface passing through the center of the inner frame (12) and parallel to the direction of relative movement of the inner frame (12).

6. The two-dimensional piezoelectric displacement stage according to claim 5, characterized in that: The thickened portion (131) is integrally formed in the middle of the two arms of the flexible hinge (13). The width of the thickened portion (131) in the horizontal direction perpendicular to the opening direction of the flexible hinge (13) is greater than the end width of the side arm of the flexible hinge (13) and the width at the connection position of the two arms.

7. The two-dimensional piezoelectric displacement stage according to claim 2, characterized in that: A displacement sensor (17) is provided on the inner rod surface of the opposite side frame rod on the side away from the lever unit (15) of the outer frame platform (11). The reading head of the displacement sensor (17) is opposite to the adjacent side rod surface of the inner frame platform (12) and forms a closed-loop control of the displacement of the inner frame platform (12).

8. The two-dimensional piezoelectric displacement stage according to any one of claims 2-7, characterized in that: The upper displacement stage unit (10a) and the lower displacement stage unit (10b) have the same structure. The relative motion direction between the outer frame stage (11) and the inner frame stage (12) of the upper displacement stage unit (10a) is Y-direction.

9. The two-dimensional piezoelectric displacement stage according to claim 8, characterized in that: The inner frame stage (12) holes of the upper and lower displacement stage units (10a, 10b) are arranged facing each other.

10. The two-dimensional piezoelectric displacement stage according to claim 9, characterized in that: The upper end face of the outer frame platform (11) of the upper displacement stage unit (10a) and the lower end face of the lower displacement stage unit (10b) are both connected to an annular platform (20), and the diameter of the central hole of the platform (20) is greater than or equal to the diameter of the central hole of the inner frame platform (12). The actuator is installed on the platform (20) of the upper displacement stage unit (10a).

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