A piezoelectric stack deformable mirror adjusted by a flexible mechanism

Abstract

The application provides a piezoelectric stack deformable mirror adjusted by a flexible mechanism, which comprises a mirror in a sheet structure, a piezoelectric ceramic fixed frame and a stack piezoelectric ceramic arranged in the piezoelectric ceramic fixed frame, the stack piezoelectric ceramic provides driving force for the deformation of the mirror, a flexible adjusting mechanism acts on the stack piezoelectric ceramic, the flexible adjusting mechanism can adjust the relative position between the stack piezoelectric ceramic and the mirror, so that the stack piezoelectric ceramic is close to or far away from the mirror, the flexible adjusting mechanism indirectly acts on the mirror by adjusting the position of the stack piezoelectric ceramic, so as to adjust the surface shape of the mirror, and through the arrangement of the flexible adjusting mechanism, the problem that part of the correction ability is sacrificed when the initial control amount is applied to the deformable mirror is solved, so that the deformable mirror can still maintain high wavefront distortion correction ability after the initial surface shape is optimized.

Description

Technical Field

[0001] This invention relates to the field of deformable mirror structure technology, and in particular to a piezoelectric stack deformable mirror that is adjustable by a flexible mechanism. Background Technology

[0002] A deformable mirror mainly consists of two parts: a drive mechanism and a reflective thin mirror. The drive mechanism comprises multiple drive units, each of which generates a corresponding driving force after receiving a control command. These driving forces act on the reflective mirror surface, changing its shape and thus correcting the distorted wavefront in the optical system.

[0003] Deformable mirrors compensate for wavefront phase errors by adjusting the shape of their mirror surface. Based on their different reflective mirror structure design principles, they are mainly divided into two types: continuous surface and discrete surface. In adaptive optics systems, continuous surface deformable mirrors play a crucial role as important wavefront correction devices. They possess advantages such as high correction accuracy and seamless surface continuity, while causing relatively small mirror deformation. Continuous surface deformable mirrors can be further divided into integral drive and discrete drive types based on their driving structure. Integral drive deformable mirrors, such as transverse piezoelectric deformable mirrors and thin-mode deformable mirrors, have a single, integrated actuator that controls voltage to achieve uniform deformation of the mirror surface, correcting wavefront distortion in low-order modes. Unlike integral drive deformable mirrors, discrete drive deformable mirrors have independent driving units that are all in contact with the mirror. Under the control of voltage, deformation occurs only in specific local areas. The force output by the actuator can deform the mirror; examples include actuators using stacked piezoelectric ceramics or voice coil motors.

[0004] When designed with actuators arranged parallel to the mirror surface, continuous surface deformable mirrors typically correct specific aberrations, such as defocus and astigmatism, limiting their applicability in adaptive optics systems. Conversely, when the actuators are driven perpendicular to the mirror surface, continuous surface deformable mirrors can correct aberrations of all orders with high accuracy, and are therefore widely used in adaptive optics systems.

[0005] In the fabrication and assembly of various deformable mirrors, the assembly method of the drive structure and the reflector is a technical challenge. As precision optical components, reflectors have very high surface flatness accuracy, typically on the nanometer scale. During the assembly of deformable mirrors, interference between the reflector and other structures can easily introduce additional stress. For example, adhesives are generally used to bond the mirror to a flexible mechanism, but the adhesive generates uneven stress during curing. Furthermore, to ensure the reliability of the mechanical assembly, the adhesive used must have very high bonding strength. This makes it almost impossible to adjust and optimize a few drive units with unsatisfactory bonding effects after the deformable mirror is fabricated. Consequently, the initial surface shape of the deformable mirror without applied control parameters deviates significantly from our technical specifications. To improve control performance, it is necessary to apply initial control parameters to the deformable mirror to actively flatten the mirror surface; however, this sacrifices some of the deformable mirror's ability to correct wavefront distortion. Summary of the Invention

[0006] The purpose of this invention is to solve the technical problem in the prior art where an initial control amount is applied to the deformable mirror to actively flatten the mirror surface, but this behavior sacrifices the deformable mirror's ability to partially correct wavefront distortion.

[0007] To address the aforementioned technical problems, this invention provides a piezoelectric stacked deformable mirror adjustable by a flexible mechanism, comprising: a sheet-like reflector, a piezoelectric ceramic fixing frame, and stacked piezoelectric ceramics disposed within the piezoelectric ceramic fixing frame. The stacked piezoelectric ceramics provide a driving force for the deformation of the reflector. A flexible adjustment mechanism acts on the stacked piezoelectric ceramics, which can adjust the relative position between the stacked piezoelectric ceramics and the reflector, causing the stacked piezoelectric ceramics to move closer to or further away from the reflector. By adjusting the position of the stacked piezoelectric ceramics, the flexible adjustment mechanism indirectly acts on the reflector to adjust the surface shape of the reflector.

[0008] Furthermore, it also includes a first flexible mechanism disposed between the piezoelectric ceramic fixing frame and the non-reflective surface of the reflector. The first flexible mechanism is fixedly connected to the piezoelectric ceramic fixing frame and the reflector. The first flexible mechanism can transmit the driving force generated by the stacked piezoelectric ceramic under the inverse piezoelectric effect to the reflector and provide a rebound force during the process of the mirror surface recovering its own shape.

[0009] Furthermore, it also includes a first flexible mechanism disposed between the piezoelectric ceramic fixing frame and the non-reflective surface of the reflector. The first flexible mechanism is fixedly connected to the piezoelectric ceramic fixing frame and the reflector. The first flexible mechanism can transmit the driving force generated by the stacked piezoelectric ceramic under the inverse piezoelectric effect to the reflector and provide a rebound force during the process of the mirror surface recovering its own shape.

[0010] Furthermore, the base includes an integrally formed support wall and a mounting part, and the support arm has three or more. One end of the support wall facing outward is connected to the piezoelectric ceramic fixing frame, and the other end supports the mounting part. The connecting part is set on the mounting part.

[0011] Furthermore, the base is a triangular prism, and flexible grooves that run through both ends of the base are opened near the three sides of the base. Each flexible groove is open on one side to form three support arms.

[0012] Furthermore, the connecting part is a cylindrical structure extending from the end of the mounting part near the reflector toward the reflector, and the end of the connecting part near the reflector has a chamfer.

[0013] Furthermore, the piezoelectric ceramic fixing frame is a cylindrical structure, including a cylindrical body and a cylindrical base. The cylindrical body and the cylindrical base form a cavity for accommodating and stacking piezoelectric ceramics. A through hole communicating with the cavity is opened at one end of the cylindrical body near the first flexible structure.

[0014] Furthermore, an opening is provided at the bottom of the cylinder base, through which the flexible adjustment mechanism acts on the stacked piezoelectric ceramics.

[0015] Furthermore, a second flexible mechanism made of flexible material is provided at the bottom opening of the cylinder base. The second flexible mechanism is located between the flexible adjustment mechanism and the stacked piezoelectric ceramic. The force generated by the adjustment of the flexible adjustment mechanism is transmitted to the stacked piezoelectric ceramic through the second flexible mechanism.

[0016] Furthermore, the second flexible mechanism is an I-shaped flexible mechanism fixedly installed at the bottom opening of the cylinder seat.

[0017] As can be seen from the above technical solution, the beneficial effects of the present invention are as follows:

[0018] First, by setting up a flexible adjustment mechanism, the problem of sacrificing some correction capability when applying initial control values ​​to the deformable mirror is solved, so that the deformable mirror can still maintain a high wavefront distortion correction capability after initial surface optimization.

[0019] Second, a first flexible mechanism serves as the force transmission intermediary connecting the reflector and the stacked piezoelectric ceramics, transmitting the driving force generated by the inverse piezoelectric effect and the pre-tightening force of the pre-tightening structure, thereby enabling rapid adjustment or restoration of the reflector's surface shape. This separates the optical structural elements from the electromechanical structural components, allowing for independent assembly, debugging, and control. This significantly improves the overall integration of the deformable mirror structure, reduces assembly and debugging time costs, increases the manufacturing efficiency of the deformable mirror, and makes it easier to obtain the required surface shape specifications.

[0020] Third, an I-shaped flexible mechanism is used as the force transmission structure connecting the stacked piezoelectric ceramics and the fine-pitch thread adjusting rod. The force output by rotating the fine-pitch thread will drive the I-shaped flexible mechanism to deform, thereby changing the longitudinal position of the stacked piezoelectric ceramics. This further refines the relationship between the fine-pitch thread lead and the longitudinal output displacement, allowing for higher-resolution fine-tuning to ensure that the initial mirror surface shape meets the required specifications.

[0021] Fourth, it is easy to repair and maintain. Due to the adoption of the two flexible mechanisms mentioned above, the deformable mirror structure is modularized and provides protection for the stacked piezoelectric ceramics. If the working effect of individual drive structure units is found to be poor, the mirror can be easily disassembled and the drive unit replaced. If the mirror is scratched or damaged, it can be easily replaced, which reduces the production and maintenance cost of deformable mirrors and improves their service life. Attached Figure Description

[0022] Figure 1 This is a cross-sectional view of the assembly effect of the dual flexible mechanism provided in this application in the drive channel.

[0023] Figure 2 This is an exploded view of the assembly effect of the dual flexible mechanism provided in this application in the drive channel.

[0024] Figure 3 This is the first flexible mechanism illustration provided in this application.

[0025] Figure 4 This is a schematic diagram of the flexible mechanism base and piezoelectric ceramic fixing frame provided in this application.

[0026] Figure 5 This is a schematic diagram of the structure of the cylindrical base provided in this application. Detailed Implementation

[0027] Typical embodiments embodying the features and advantages of the present invention will be described in detail in the following description. It should be understood that the present invention can have various variations in different embodiments without departing from the scope of the present invention, and the descriptions and illustrations herein are for illustrative purposes only and not intended to limit the present invention.

[0028] In the description of this application, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," and "counterclockwise," etc., indicating orientation or positional relationships based on the orientation or positional relationships shown in the accompanying drawings, are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this application. Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, features defined with "first" and "second" may explicitly or implicitly include one or more of the stated features. In the description of this application, "a plurality of" means two or more, unless otherwise explicitly specified.

[0029] To further illustrate the principles and structure of the present invention, preferred embodiments of the present invention will now be described in detail with reference to the accompanying drawings.

[0030] refer to Figure 1-5 The present invention includes:

[0031] The reflector 100 is a circular sheet structure with a reflective surface and a non-reflective surface. The non-reflective surface is fixed to the top end 201 of the first flexible mechanism and is a cylindrical structure with a diameter much smaller than that of the reflector 100. Its position corresponds to the position of each driving channel of the deformable mirror.

[0032] The first flexible mechanism 200 has a base in the shape of a triangular prism. Flexible grooves 204 are provided on the three sides of the base, which pass through both ends of the base, to improve the flexibility of the first flexible structure. Positioning holes 202 are machined, a cylinder 201 of a certain height is stretched, and a chamfer 203 is made at the top to improve the resolution of contact with the reflective mirror surface.

[0033] The piezoelectric ceramic fixing frame 300 is a cylindrical structure, including a cylindrical body and a cylindrical base. A cavity 303 is formed inside to accommodate the stacked piezoelectric ceramics. The surrounding walls of the cavity 303 are in contact with the outer surface of the stacked piezoelectric ceramics 400. The cavity 303 can guide the stacked piezoelectric ceramics 400 so that the stacked piezoelectric ceramics 400 can only be moved and adjusted in the vertical direction. A circular through hole 302 is opened at the top of the cylindrical body, and a positioning threaded hole 301 is machined to cooperate with the positioning hole 202 of the first flexible mechanism.

[0034] The stacked piezoelectric ceramic 400 serves as the driving structure. It consists of an adapter ball joint 401 and a piezoelectric ceramic sheet 402. Applying a control voltage to the stacked piezoelectric ceramic 400 will generate a driving force. The adapter ball joint 401 ensures that the output driving force is vertically upward.

[0035] The cylinder base 500 is a cylindrical structure with an opening at the bottom, and an I-shaped flexible mechanism 502 is machined at the bottom opening.

[0036] The fine-pitch thread adjustment table 600 is a cylindrical structure with a fine-pitch thread hole machined at the bottom to fit with the fine-pitch thread adjustment rod 700. A circular hole of a certain depth is opened at the top to meet the lightweight requirements of the deformable mirror.

[0037] The fine-threaded adjusting rod 700 has a machined transition ball head 701 at its head, which is tangentially assembled with the I-shaped flexible mechanism 502 to provide preload force for the stacked piezoelectric ceramic 400;

[0038] The fine-pitch nut 800, with its fine-pitch thread machined in the center, mates with the fine-pitch thread adjusting rod 700, allowing for precise adjustment of the positioning of the stacked piezoelectric ceramic 400.

[0039] The reflector 100 is bonded to the first flexible mechanism 200 using an adhesive, and the first flexible mechanism 200 is then fitted to the top of the piezoelectric ceramic fixing frame 300. Stacked piezoelectric ceramics 400 are placed into the cavity 303 formed by the cylinder body and cylinder seat of the piezoelectric ceramic fixing frame 300. The cylinder seat 500 acts as a limiting device and is fitted to the fine thread adjusting table 600. The fine thread adjusting rod 700 is positioned by the fine thread adjusting table 600. The position of the stacked piezoelectric ceramics 400 can be adjusted by the fine thread adjusting rod 700 to adjust the initial position. The initial reflector surface shape is determined and an initial preload is provided. Once the surface shape meets the requirements, it is locked using a fine-tooth nut 800. The power supply line of the stacked piezoelectric ceramic 400 is connected to an external power source. When voltage is applied, the reverse piezoelectric effect is generated, which elongates the stacked piezoelectric ceramic 400, causing the first flexible mechanism 200 to deform and pushing the reflector 100 to deform. Since the reflector 100 is bonded to the first flexible mechanism 200, the rebound force of the first flexible mechanism 200 will accelerate the process of the mirror surface returning to its original shape and improve the integration of the deformable mirror structure.

[0040] The method of using the dual flexible mechanism according to the present invention will be described in detail below with reference to the accompanying drawings.

[0041] The first flexible mechanism is used to: reduce weight and quickly restore the initial shape of the mirror surface.

[0042] like Figure 2 As shown, the reflector 100 is bonded to the top end 201 of the first flexible mechanism using adhesive, and the positioning hole 202 of the first flexible mechanism is fitted with the positioning threaded hole 301 of the piezoelectric ceramic fixing frame for installation; the stacked piezoelectric ceramic 400 is placed in the cavity 303 within the piezoelectric ceramic fixing frame 300, and the stacked piezoelectric ceramic adapter ball head 401 is tangent to the bottom of the first flexible mechanism 200. The design of the first flexible mechanism simplifies the assembly method of push rods and springs used in traditional deformable mirrors, achieving weight reduction. Furthermore, when the supply voltage decreases or is set to zero, the rebound force of the first flexible mechanism 200 itself will accelerate the process of the reflector surface returning to its original shape, quickly restoring the initial surface shape of the mirror.

[0043] Application of I-shaped flexible mechanisms: weakening, strengthening, or non-destructive transmission of preload / driving force.

[0044] like Figure 2As shown, the reflector 100 is bonded to the top 201 of the first flexible mechanism using adhesive, and the positioning hole 202 of the first flexible mechanism is fitted with the positioning threaded hole 301 of the piezoelectric ceramic fixing frame. The stacked piezoelectric ceramic 400 is placed in the bottom hole 303 of the piezoelectric ceramic fixing frame, and the stacked piezoelectric ceramic adapter ball head 401 is tangent to the bottom of the first flexible mechanism 200. The cylinder seat 500 is installed as a limiting device and fits into the fine thread adjusting table 600. The fine thread adjusting rod 700 is positioned through the threaded hole 602 of the fine thread adjusting table, and the adapter ball head 701 of the fine thread adjusting rod is tangent to the bottom 502 of the I-shaped flexible mechanism. By rotating the fine thread adjusting rod 700, the bottom 502 of the cylinder seat is pushed, thereby adjusting the longitudinal position of the stacked piezoelectric ceramic 400. The stacked piezoelectric ceramic adapter ball head 402 pushes the first flexible mechanism 200 to precisely adjust the surface shape of the reflector. At the same time, it also enables the weakening, enhancement, or lossless transmission of preload and driving force of stacked piezoelectric ceramics, thereby improving the service life of deformable mirror structures.

[0045] Although the invention has been described with reference to several typical embodiments, it should be understood that the terminology used is illustrative and exemplary, and not restrictive. Since the invention can be embodied in many forms without departing from the spirit or essence of the invention, it should be understood that the above embodiments are not limited to any of the foregoing details, but should be interpreted broadly within the spirit and scope defined by the appended claims. Therefore, all variations and modifications falling within the scope of the claims or their equivalents should be covered by the appended claims.

Claims

1. A piezoelectric stacked deformable mirror adjustable by a flexible mechanism, characterized in that, The device includes a sheet-like reflector, a piezoelectric ceramic fixing frame, and stacked piezoelectric ceramics disposed within the piezoelectric ceramic fixing frame. The stacked piezoelectric ceramics provide a driving force for the deformation of the reflector and act on an adjustment mechanism that adjusts the relative position between the stacked piezoelectric ceramics and the reflector, so that the stacked piezoelectric ceramics move closer to or further away from the reflector. By adjusting the position of the stacked piezoelectric ceramics, the adjustment mechanism indirectly acts on the reflector to adjust the surface shape of the reflector. It also includes a first flexible mechanism disposed between the piezoelectric ceramic fixing frame and the non-reflective surface of the reflector. The first flexible mechanism is fixedly connected to the piezoelectric ceramic fixing frame and the reflector. The first flexible mechanism can transmit the driving force generated by the stacked piezoelectric ceramic under the inverse piezoelectric effect to the reflector and provide a rebound force in the process of the mirror surface restoring its own shape. The piezoelectric ceramic fixing frame includes a cylindrical base with an opening at the bottom of the cylindrical base. A second flexible mechanism made of flexible material is provided at the bottom opening of the cylindrical base. The second flexible mechanism is located between the adjustment mechanism and the stacked piezoelectric ceramics. The force generated by the adjustment mechanism is transmitted to the stacked piezoelectric ceramics through the second flexible mechanism. The second flexible mechanism is an I-shaped flexible mechanism fixedly installed at the bottom opening of the cylindrical base. The adjustment mechanism includes a fine-threaded adjustment rod, the head of which is machined with an adapter ball head. The adapter ball head is tangentially assembled with the I-shaped flexible mechanism. The adjustment mechanism provides preload force for the stacked piezoelectric ceramics. The first flexible mechanism includes a base made of flexible material, a connecting part set on the base, the base being connected to a piezoelectric ceramic fixing frame, the connecting part being connected to a reflector, and the driving force generated by stacking piezoelectric ceramics acting directly on the base. The base deforms under the action of the driving force, causing the connecting part to move toward the reflector, thereby deforming the reflector. The base includes an integrally formed support wall and a mounting part. There are three or more support arms. One end of the support wall facing outward is connected to the piezoelectric ceramic fixing frame, and the other end supports the mounting part. The connecting part is set on the mounting part. The base is a triangular prism, and flexible grooves that run through both ends of the base are opened near the three sides of the base. Each flexible groove is open on one side to form three support arms.

2. The piezoelectric stacked deformable mirror adjustable by a flexible mechanism according to claim 1, characterized in that, The connecting part is a cylindrical structure extending from the end of the mounting part near the reflector toward the reflector, and the end of the connecting part near the reflector has a chamfer.

3. The piezoelectric stacked deformable mirror adjustable by a flexible mechanism according to claim 1, characterized in that, The piezoelectric ceramic fixing frame is a cylindrical structure. The piezoelectric ceramic fixing frame also includes a cylindrical body. A cavity is formed inside the cylindrical body and the cylindrical base to accommodate and stack piezoelectric ceramics. A through hole communicating with the cavity is opened at one end of the cylindrical body near the first flexible structure.

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