A mirror and a mirror design method

Abstract

The application is suitable for the field of reflectors, and discloses a reflector and a reflector design method. The method comprises the following steps: obtaining optical parameters of a main mirror body, a distribution mode of reinforcing ribs, support point positions and sizes of taper sleeves, and calculating interval distances of the reinforcing ribs and cutting edge angles; determining positions of the reinforcing ribs on the back of the main mirror body based on the distribution mode and the interval distances of the reinforcing ribs, and forming support holes that are adapted to the taper sleeves at the support point positions according to the sizes of the taper sleeves to obtain an initial version of the main mirror; performing weight reduction processing and enhancement processing on the initial version of the main mirror based on the cutting edge angles to obtain a lightweight main mirror; designing the taper sleeves according to the sizes of the taper sleeves and determining support positions of the taper sleeves; determining an angle between an upper flexible claw of a flexible joint and a line connecting the flexible joint and a center of the main mirror, an angle between a lower flexible claw of the flexible joint and the line connecting the flexible joint and the center of the main mirror, and a width of a first flexible joint groove of the upper flexible claw through simulation analysis, and the method can improve the surface shape precision and the structural stability of the reflector.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of mirrors, in particular to a mirror and a mirror design method. BACKGROUND

[0002] In the field of optical systems, as a core imaging element, the surface shape precision (often measured by RMS value) of the mirror directly determines the imaging quality of the optical system, and needs to maintain high consistency with the ideal surface shape under the working conditions of gravity, forced displacement, etc., so the mirror assembly design is a key difficulty in the research and development of optical systems.

[0003] At present, the existing mirror design mainly focuses on the optimization of single component parameters, and lacks the consideration of the collaborative design of lightweight primary mirror, cone sleeve and flexible joint: on the one hand, in the design of the primary mirror body, the matching of optical parameters such as clear aperture and hole diameter and the distribution and spacing of reinforcing ribs is insufficient, and the position of reinforcing ribs is often determined by experience, which may lead to uneven stress distribution of the primary mirror and large surface shape error under the action of gravity; on the other hand, the support point position planning and the size of the cone sleeve are not well matched, and the local stress concentration of the primary mirror is easily caused after the support hole is processed, which further affects the surface shape stability.

[0004] At the same time, the weight reduction processing of the primary mirror usually adopts fixed cutting angle or simple hollowing method, without dynamic optimization of the cutting parameter combined with the surface shape evaluation function, so it is difficult to balance between weight reduction and structural stiffness; and the flexible joint is a key component for balancing the forced displacement, and the existing design usually uses conventional structure, without simulation optimization of the relation between the flexible jaw angle, flexible joint slot width and stress characteristics of the primary mirror, so the flexible joint cannot balance flexibility (stress balancing ability) and rigidity (support strength), and is easy to cause mirror surface shape distortion due to forced displacement transmission.

[0005] Therefore, the existing technology needs to be improved and developed. SUMMARY

[0006] The first object of the present application is to provide a mirror design method, which aims to solve the technical problems of insufficient surface shape precision and structural stability of the existing mirror.

[0007] To achieve the above object, the scheme provided by the present application is:

[0008] A mirror design method is disclosed. The mirror design method is used to design a mirror comprising a lightweight primary mirror, a conical sleeve, and a flexible joint. The lightweight primary mirror includes a primary mirror body and reinforcing ribs. The mirror design method includes: acquiring the optical parameters of the primary mirror body, the distribution pattern of the reinforcing ribs, the position of the support points, and the dimensions of the conical sleeve; calculating the spacing distance and cutting angle of the reinforcing ribs; determining the position of the reinforcing ribs on the back of the primary mirror body based on the distribution pattern and spacing distance of the reinforcing ribs; and determining the position of the reinforcing ribs on the support points according to the dimensions of the conical sleeve. A support hole is formed at the support point to fit the conical sleeve, resulting in an initial version of the primary mirror. The initial version of the primary mirror is then weight-reduced based on the chamfer angle, and reinforced after weight reduction to obtain a lightweight primary mirror. The conical sleeve is designed according to its dimensions, and its support position is determined. The flexible joint is determined to be a three-claw type. Simulation analysis is used to determine the angle between the upper flexible claw and the line connecting the flexible joint and the center of the primary mirror, as well as the angle between the lower flexible claw and the line connecting the flexible joint and the center of the primary mirror. The width of the first flexible joint groove of the upper flexible claw is also determined.

[0009] Preferably, the step of acquiring the optical parameters of the primary mirror body, the distribution pattern of the reinforcing ribs, the position of the support points, and the size of the conical sleeve, and calculating the spacing distance and cutting angle of the reinforcing ribs, includes: acquiring the optical parameters of the primary mirror body, the distribution pattern of the reinforcing ribs, the position of the support points, and the size of the conical sleeve; the optical parameters of the primary mirror body include the aperture and the diameter of the central shield; the distribution pattern of the reinforcing ribs is triangular; the position of the support points is the intersection of the reinforcing ribs; and they are distributed symmetrically around the back center of the primary mirror body at 120°; calculating the spacing distance of the reinforcing ribs using a first surface shape evaluation function; and calculating the cutting angle using a second surface shape evaluation function.

[0010] Preferably, the interval distance is defined as The first surface evaluation function is ,but Represented as:

[0011]

[0012] In the formula, , , These represent the fitted curves of the first surface shape, respectively. Curve functions in the X, Y, and Z directions, As a weighting factor, By solving the first surface evaluation function The minimum value can be used to obtain the spacing of the reinforcing ribs. .

[0013] Preferably, the cutting angle is defined as follows: The evaluation function for the second surface shape is: The second surface shape evaluation function is represented as:

[0014]

[0015] In the formula, are the third surface shape fitting curve graph The curve function about X, Y, Z directions, is a weighting factor, The cutting edge angle can be obtained by solving the minimum value of the second surface shape evaluation function .

[0016] Preferably, the initial version of the main mirror is subjected to weight reduction processing based on the cutting edge angle, and the initial version of the main mirror after weight reduction is subjected to enhancement processing to obtain a lightweight main mirror, comprising: performing lightweight cutting edge processing on the initial version of the main mirror along the extension direction of the reinforcing rib according to the cutting edge angle; performing flanging processing on the reinforcing rib in the non-cutting edge area of the initial version of the main mirror after cutting edge, and designing lightweight holes at positions with a thickness exceeding a preset thickness threshold to form a lightweight main mirror.

[0017] Preferably, the support position of the cone sleeve should be on the same numerical plane as the center of mass of the lightweight main mirror.

[0018] Preferably, the flexible joint is determined to be a three-prong flexible joint, and the angle between the upper flexible prong of the flexible joint and the line connecting the flexible joint and the center of the main mirror and the angle between the lower flexible prong of the flexible joint and the line connecting the flexible joint and the center of the main mirror are determined by simulation analysis when determining the width of the first flexible joint groove of the upper flexible prong, and the width of the first flexible joint groove of the upper flexible prong is determined by a third surface shape evaluation function, and the width of the first flexible joint groove is defined as , and the third surface shape evaluation function is , which is represented as:

[0019]

[0020] In the formula, are the third surface shape fitting curve graph The curve function about X, Y, Z directions and forced displacement, , is a weighting factor, The values of the weighting factor are 0.2, 0.2, 0.2, and 0.4, respectively, and the width of the first flexible joint groove can be obtained by solving the minimum value of the third surface shape evaluation function , and takes a multiple of 0.1.​​​​​​

[0021] The second object of the present application is to provide a mirror, comprising a lightweight primary mirror, a taper sleeve and a flexible joint, the lightweight primary mirror comprising a primary mirror body and a reinforcing rib, the reinforcing rib being arranged on the back of the primary mirror body, and the back of the primary mirror body being provided with a support hole and a lightweight hole, the primary mirror body being provided with a cut edge bevel, the taper sleeve being installed in the support hole, and the flexible joint being installed in the taper sleeve, the flexible joint comprising a first circular ring, a second circular ring, an intermediate column, an upper flexible claw and a lower flexible claw, the upper flexible claw being provided with three, the three upper flexible claws being evenly arranged on the upper part of the intermediate column along the circumference of the intermediate column, the top edge of the upper flexible claw extending upwardly with an L-shaped connecting part, the L-shaped connecting part being connected with the first circular ring, the upper flexible claw being provided with oppositely arranged first and second flexible joint grooves, the first and second flexible joint grooves being arranged in an L shape, and the first and second flexible joint grooves being arranged in a non-interleaved manner in the axial direction, the lower flexible claw being provided with three, the three lower flexible claws being evenly arranged on the lower part of the intermediate column along the circumference of the intermediate column, and the bottom edge of the three lower flexible claws being provided with a stepped part, the stepped part being connected with the top and inner side wall of the second circular ring, respectively.

[0022] Preferably, the clear aperture is 610 mm, the diameter of the through hole is 170 mm, the interval distance of the reinforcing rib is 86.5 mm, the angle between the extension line of the cut edge bevel and the back plane of the primary mirror body is 25°, the maximum diameter of the taper sleeve is 80 mm, the minimum diameter is 74 mm, and the taper is 2.37°, and the width of the first flexible joint groove is 2.0 mm.

[0023] The present application precisely calculates the interval of the reinforcing rib and the cut edge angle based on the optical parameters of the primary mirror body, ensures that the layout of the reinforcing rib is scientific and reasonable, and through the design of the support hole with the size of the taper sleeve and the targeted weight reduction and enhancement treatment, the structural strength is ensured while the primary mirror is lightened, finally, the claw angle and the flexible joint groove width of the three-claw flexible joint are optimized combined with simulation analysis, so that the matching degree of the parameters of each component is high, the assembly cooperativity is good, the overall structural stability and surface accuracy of the mirror are effectively improved, and the weight reduction demand and mechanical properties are considered. BRIEF DESCRIPTION OF DRAWINGS

[0024] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the following will briefly introduce the drawings needed to be used in the embodiments or the prior art description. Obviously, the drawings in the following description only show some embodiments of the present application, and for those skilled in the art, other drawings can also be obtained from the structures shown in the drawings without creative labor.

[0025] Figure 1 is the flow chart of the mirror design method provided by the embodiments of the present application;

[0026] Figure 2 is an exploded view of the reflector provided by an embodiment of the present application;

[0027] Figure 3 is a front view of the reflector provided by an embodiment of the present application;

[0028] Figure 4 is a top view provided by an embodiment of the present application;

[0029] Figure 5 is a structural schematic view of the flexible joint provided by an embodiment of the present application;

[0030] Figure 6 is a front view of the flexible joint provided by an embodiment of the present application;

[0031] Figure 7 is a first surface shape fitting curve diagram provided by an embodiment of the present application;

[0032] Figure 8 is a primary mirror shape deformation simulation diagram provided by an embodiment of the present application;

[0033] Figure 9 is a second surface shape fitting curve diagram provided by an embodiment of the present application;

[0034] Figure 10 is a flexible joint installation position simulation curve diagram provided by an embodiment of the present application;

[0035] Figure 11 is a third surface shape fitting curve diagram provided by an embodiment of the present application.

[0036] BRIEF DESCRIPTION OF THE DRAWINGS

[0037] 10, lightweight primary mirror; 11, primary mirror body; 111, through hole; 112, support hole; 113, lightweight hole; 12, reinforcing rib; 20, taper sleeve; 30, flexible joint; 31, first circular ring; 32, second circular ring; 33, middle column; 34, upper flexible claw; 341, L-shaped connecting part; 342, first flexible joint groove; 343, second flexible joint groove; 35, lower flexible claw; 351, step part. DETAILED DESCRIPTION

[0038] The terms "first", "second", "third", "fourth" and the like in the description and in the claims of the present application, and above-mentioned drawings, if any, are used to distinguish between similar objects and not necessarily for describing a particular sequential or chronological order. It is to be understood that the use of the terms so-termed "first", "second", "third", "fourth" and the like, if any, in the description and in the claims of the present application is not used to denote a chronological order, a certain order of use or importance, but is used to distinguish between two or more related objects or actions. It is to be understood that the data so used can be interchanged, where appropriate, so that the embodiments described herein can be carried out in other than the order shown or described herein. Furthermore, the terms "comprise" or "have" and any variations thereof are intended to cover a non-exclusive inclusion, for example, a process, method, system, product or apparatus that comprises a list of steps or units is not necessarily limited to those steps or units which are clearly recited, but can include other steps or units that are not expressly listed or inherent to such process, method, product or apparatus.

[0039] For the sake of understanding, the specific flow of the embodiments of the present application is described below. Please refer to Figure 1 In the embodiments of the present application, a mirror design method is used to realize the design of a mirror, the mirror comprising a lightweight main mirror, a cone sleeve and a flexible joint, the lightweight main mirror comprising a main mirror body and a reinforcing rib, the mirror design method comprising:

[0040] S101, obtaining the optical parameters of the main mirror body, the distribution mode of the reinforcing rib, the support point position and the size of the cone sleeve, and calculating the interval distance and the cutting edge angle of the reinforcing rib;

[0041] S102, determining the position of the reinforcing rib on the back of the main mirror body based on the distribution mode and the interval distance of the reinforcing rib, and forming a support hole adapted to the cone sleeve at the support point position according to the size of the cone sleeve, to obtain an initial version of the main mirror;

[0042] S103, performing weight reduction processing on the initial version of the main mirror based on the cutting edge angle, and performing enhancement processing on the initial version of the main mirror after weight reduction, to obtain the lightweight main mirror;

[0043] S104, designing the cone sleeve according to the size of the cone sleeve, and determining the support position of the cone sleeve;

[0044] S105, determining that the flexible joint is a three-prong flexible joint, determining the angle between the upper flexible prong of the flexible joint and the line connecting the flexible joint and the center of the main mirror, and the angle between the lower flexible prong of the flexible joint and the line connecting the flexible joint and the center of the main mirror, and determining the width of the first flexible joint groove of the upper flexible prong.

[0045] In this embodiment, in step S101, the optical parameters of the main mirror body, the distribution mode of the reinforcing rib, the support point position and the size of the cone sleeve are obtained, and the interval distance and the cutting edge angle of the reinforcing rib are calculated, comprising:

[0046] The optical parameters of the primary mirror body, the distribution of the reinforcing ribs, the position of the support points, and the size of the cone sleeve are obtained. The optical parameters of the primary mirror body include the aperture and the diameter of the central shield. The distribution of the reinforcing ribs is triangular, and the position of the support points is the intersection of the reinforcing ribs. They are distributed symmetrically at 120° around the center of the back of the primary mirror body.

[0047] The spacing of the stiffeners is calculated using the first surface shape evaluation function;

[0048] The tangent angle is calculated using the second face shape evaluation function.

[0049] It should be noted that there are various forms of reinforcing ribs, among which triangular ribs have high stability. In this embodiment, the reinforcing ribs are distributed in a triangular pattern. To ensure that the reflector is subjected to uniform force in all directions, the reinforcing ribs are centrally symmetrically distributed at 120°. The selection of the support point position is determined by the intersection of the reinforcing ribs. In order to ensure that the primary mirror is subjected to uniform force, the support position is located at the intersection of the reinforcing ribs, and the three support points should be centrally symmetrically distributed at 120° around the center of the back.

[0050] In this embodiment, the spacing between the reinforcing ribs is defined as... ,by As a variable, through continuous change The numerical values ​​are used to simulate and analyze the RMS value of the surface shape of the reflector, and the results are presented as... Plot the first surface shape fitting curve with the x-axis as the x-axis and the RMS values ​​of the surface shape under gravity in the X, Y, and Z directions as the y-axis, as shown in the figure. Figure 7 As shown in the first surface shape fitting curve graph, the left vertical axis represents the Z-direction surface shape, and the right vertical axis represents the X and Y-direction surface shapes. It can be seen that the X and Y-direction curves have highly consistent shapes, which are significantly different from the Z-direction curve. This indicates that the x-coordinate corresponding to the optimal value of the Z-direction surface shape is not the same as the x-coordinates corresponding to the X and Y terms. Therefore, a weighted average is used to find the optimal solution. Assume the first surface shape fitting curve graph... The curve functions for the X, Y, and Z directions are respectively , , And assign weighting factors Then the first facet evaluation function Represented as:

[0051] .

[0052] In the formula, By solving the first surface evaluation function The minimum value can be used to obtain the spacing of the reinforcing ribs. .

[0053] In the embodiment, the light aperture is 610 mm, the diameter of the through hole is 170 mm, and the interval distance of the reinforcing ribs is 86.5 mm.

[0054] In the embodiment, the positions with large deformation are found, and weight reduction processing is performed, that is, lightweight trimming processing is performed on the mirror, and the optimal trimming angle is obtained through simulation numerical fitting. From the simulation analysis result of the mirror, the area with large deformation is the area far from the support point. The farther the position is from the support point, the poorer the support effect is, the greater the influence of gravity is, and the larger the deformation is. As shown in FIG. 6, the blue area represents the area with small deformation, and the yellow and red areas represent the areas with large deformation. In order to further optimize the EMS value of the surface shape, further weight reduction processing is performed on the three positions with large surface shape deformation. Figure 8

[0055] If too little is cut off, the optimization effect is not obvious, and too much is cut off, which will affect the structural stiffness. Therefore, the simulation analysis and curve fitting are used to determine the trimming angle.

[0056] As shown in FIG. 7, the second surface shape fitting curve is drawn with the trimming angle as the horizontal axis and the corresponding mirror surface shape RMS value as the vertical axis. As shown in FIG. 8, the Z direction is opposite to the X and Y directions, and the overall value of the X and Y directions is small, and the value of the Z direction is large. Assuming that the Figure 9 Figure 9 of the second surface shape fitting curve is the minimum value, the trimming angle The curve functions of the X, Y and Z directions are respectively , , , and the weighting factors are allocated. The second surface shape evaluation function is represented as:

[0057] .

[0058] In the formula, the minimum value of the second surface shape evaluation function is obtained by solving the minimum value of the second surface shape evaluation function , and the trimming angle is obtained. In the embodiment, as shown in FIG. 9, the trimming angle Figure 4 is .

[0059] In the embodiment, in step S103, the initial version of the main mirror is subjected to weight reduction processing based on the trimming angle, and the initial version of the main mirror after weight reduction is subjected to enhancement processing to obtain a lightweight main mirror, including:

[0060] The initial version of the main mirror is subjected to lightweight trimming processing along the extension direction of the reinforcing rib according to the trimming angle;

[0061] ​The stiffeners in the non-edged area of the initial version of the edged main mirror are turned up, and lightweight holes are designed at positions with a thickness exceeding a preset thickness threshold, to form a lightweight main mirror.

[0062] In this embodiment, to increase the strength and rigidity of the lightweight main mirror, the stiffeners in the non-edged area of the initial version of the edged main mirror are turned up, i.e. turned up on the plane. After the turning-up, the material is too thick at some positions. To ensure the uniformity of the thickness of the lightweight main mirror, lightweight holes are designed at the positions where the material is too thick, to ensure the uniformity of the thickness.

[0063] In step S104, in this embodiment, the support position of the cone sleeve should be on the same numerical plane as the center of mass of the lightweight main mirror.

[0064] Specifically, in this embodiment, the bottom of the cone sleeve is 55 mm away from the upper edge position of the support hole.

[0065] In this embodiment, the maximum diameter of the cone sleeve is 80 mm, the minimum diameter is 74 mm, and the taper is 2.37°. The support hole is adapted to the cone sleeve, and specifically, the size of the support hole is consistent with the size of the cone sleeve.

[0066] In step S105, in this embodiment, the installation mode of the flexure itself will affect the mirror, i.e. the angle at which the flexure is installed will affect the final result, as shown in Figure 3 , assuming that the angle between the upper flexure claw of the flexure and the line connecting the flexure and the center of the main mirror is , due to the symmetry of the flexure itself, only the change of the β angle within 0°~120° needs to be considered, and is taken as the independent variable, with a value of 0~120, for simulation analysis, and the simulation result RMS is the dependent variable. The obtained results are plotted and fitted as a simulation curve, to obtain the flexure installation position simulation curve, as shown in Figure 10 . As can be seen from the figure, when β is 0°, i.e. when the upper flexure claw of the flexure points to the center of the main mirror, the surface shape is optimal in this case. Similarly, when the lower flexure claw of the flexure points to the center of the main mirror, the surface shape is optimal in this case.

[0067] In this embodiment, as shown in Figure 5 and Figure 6 , the flexibility of the flexure is mainly determined by the first flexure slot and the second flexure slot of the upper flexure claw. The flexibility of the flexure is adjusted by adjusting the width of the first flexure slot and the second flexure slot. It should be noted that the higher the flexibility of the flexure, the stronger the stress that the flexure can balance (manifested as a better surface shape under forced displacement), and the worse the support strength (manifested as a worse surface shape under the action of X, Y, and Z gravity). Figure 6 , as shown in , the width of the first flexure slot is determined by the width of the first flexure slot, the overlap width of the first flexure groove and the second flexure groove, and which affects the flexibility of the flexure, it should be noted that, may be negative, that is, the first flexure groove and the second flexure groove are staggered. The positive and negative values will have a significant impact on the flexibility of the flexure, when is positive, the first flexure groove and the second flexure groove have no staggered parts in the axial direction, at this time the flexibility is weak and the rigidity is strong. When is negative, the two flexures have staggered parts in the axial direction, at this time the flexibility is strong and the rigidity is weak. When simulating and analyzing, first set = 0, observe the simulation results, if the simulation results show that the forced displacement surface shape is poor, that is, the flexibility is not enough, then set to a negative value, otherwise set it to a positive value. In this case, according to the simulation results, it can be obtained that is positive, that is, the first flexure groove and the second flexure groove are non-staggered in the axial direction.

[0068] Further, in the case where is positive, the value of is determined by numerical simulation, and the value of is set to 0-5, and simulation and analysis are performed, and the surface shape RMS values of the surface shape under four working conditions of X, Y, Z and forced displacement 0.01mm are shown in Figure 11 . Assuming that the curve fitting functions are , , , respectively, and the weighting factors are assigned, then the third surface shape evaluation function is represented as:

[0069] .

[0070] In the formula, , , , respectively represent the curve functions of the third surface shape fitting curve graph with respect to X, Y, Z and forced displacement, , is the weighting factor, and the values of are 0.2, 0.2, 0.2 and 0.4 respectively. By solving the minimum value of the third surface shape evaluation function , the width of the first flexure groove can be obtained, and takes a multiple of 0.1.

[0071] By solving the evaluation function of the third facet The minimum value can be used to obtain the width of the first flexible joint groove. In this embodiment, the width of the first flexible joint groove is... It is 2.0mm.

[0072] In this embodiment, the spacing of the reinforcing ribs and the angle of the cutting edge are accurately calculated based on the optical parameters of the primary mirror body to ensure that the layout of the reinforcing ribs is scientific and reasonable. Then, through the design of support holes adapted to the size of the conical sleeve and targeted weight reduction and reinforcement treatment, the structural strength is ensured while achieving the lightweighting of the primary mirror. Finally, the angle of the flexible claw and the width of the flexible joint groove of the three-claw joint are optimized by combining simulation analysis, so that the parameters of each component are highly matched and the assembly coordination is good, which effectively improves the overall structural stability and surface accuracy of the reflector, and takes into account both the weight reduction requirements and mechanical performance.

[0073] Please see Figures 2-6 As shown, the present invention also provides a reflector, including a lightweight primary mirror 10, a conical sleeve 20, and a flexible joint 30. The lightweight primary mirror 10 includes a primary mirror body 11 and a reinforcing rib 12. The reinforcing rib 12 is disposed on the back of the primary mirror body 11, and the back of the primary mirror body 11 is provided with a support hole 112 and a lightweight hole 113. The primary mirror body 11 is provided with a chamfered edge. The conical sleeve 20 is installed in the support hole 112, and the flexible joint 30 is installed in the conical sleeve 20. The flexible joint 30 includes a first ring 31, a second ring 32, a central post 33, an upper flexible claw 34, and a lower flexible claw 35. Three upper flexible claws 34 are provided, and the three upper flexible claws 34 are evenly arranged along the circumference of the central post 33. At the upper part of the column 33, the top edge of the upper flexible claw 34 extends upward with an L-shaped connecting part 341, which is connected to the first ring 31. The upper flexible claw 34 is provided with a first flexible groove 342 and a second flexible groove 343 arranged opposite to each other. Both the first flexible groove 342 and the second flexible groove 343 are L-shaped and are not staggered in the axial direction. There are three lower flexible claws 35, which are evenly arranged in the lower middle part along the circumference of the middle column 33. The bottom edge of the three lower flexible claws 35 is provided with a step part 351, which is connected to the top and inner side wall of the second ring 32 respectively.

[0074] In this embodiment, the light-transmitting aperture is 610mm, the diameter of the through hole 111 is 170mm, and the spacing between the reinforcing ribs 12 is 86.5mm.

[0075] In this embodiment, the bottom of the tapered sleeve 20 is 55mm from the upper edge of the support hole 112, with a maximum diameter of 80mm, a minimum diameter of 74mm, and a taper of 2.37°. The support hole 112 is adapted to the tapered sleeve 20; specifically, the size of the support hole is the same as the size of the tapered sleeve. The bottom of the tapered sleeve 20 is 55mm from the upper edge of the support hole 112.

[0076] In the embodiment, the angle between the extension line of the beveled edge and the back plane of the main mirror body 11 is 25°. , .

[0077] In the embodiment, the width of the first flexible slot 342 is 2.0 mm. Figure 6

[0078] In the embodiment, the lightweight main mirror 10 is enhanced in structural stability by setting the reinforcing rib 12 on the back of the main mirror body 11, is adapted to the taper sleeve 20 installation by the support hole 112, and realizes weight reduction by the lightweight hole 113. The beveled edge further optimizes the structure and weight reduction effect. The flexible joint 30 adopts the basic framework of the first ring 31, the second ring 32 and the intermediate column 33. The three upper flexible claws 34 are evenly distributed along the circumference of the intermediate column 33 and are stably connected with the first ring 31 through the L-shaped connecting part. The first flexible slot 342 and the second flexible slot 343 of the upper flexible claw 34 are arranged non-interlaced in the axial direction, which can accurately balance the flexibility and rigidity. The three lower flexible claws 35 are reliably connected with the second ring 32 through the stepped part 351. The overall structure not only guarantees the lightweight demand of the reflecting mirror, but also effectively improves the surface shape precision, structural strength and anti-external force interference ability of the reflecting mirror through the accurate adaptation and reasonable layout of each component, so as to ensure the stable operation of the reflecting mirror under working conditions.

[0079] The above only describes the preferred embodiments of the present application, and does not limit the patent scope of the present application. Any equivalent structural transformation, direct / indirect application in other related technical fields within the inventive concept of the present application, and the content of the specification and drawings are included in the patent protection scope of the present application.​​

Claims

1. A method of mirror design, characterized by, The mirror design method is used for realizing design of a mirror, the mirror comprising a lightweight primary mirror, a cone sleeve and a flexible joint, the lightweight primary mirror comprising a primary mirror body and a reinforcing rib, the mirror design method comprising: obtaining optical parameters of the primary mirror body, a distribution mode of the reinforcing rib, a support point position and a size of the cone sleeve, and calculating interval distances of the reinforcing rib and a cutting edge angle; determining positions of the reinforcing rib on a back of the primary mirror body based on the distribution mode and the interval distances of the reinforcing rib, and forming a support hole adapted to the cone sleeve at the support point position according to the size of the cone sleeve, to obtain an initial version of the primary mirror; performing weight reduction processing on the initial version of the primary mirror based on the cutting edge angle, and performing enhancement processing on the initial version of the primary mirror after the weight reduction, to obtain the lightweight primary mirror; designing the cone sleeve according to the size of the cone sleeve, and determining a support position of the cone sleeve; determining the flexible joint as a three-prong flexible joint, determining an angle between an upper flexible prong of the flexible joint and a line connecting the flexible joint and a center of the primary mirror, and an angle between a lower flexible prong of the flexible joint and the line connecting the flexible joint and the center of the primary mirror through simulation analysis, and determining a width of a first flexible joint groove of the upper flexible prong; the obtaining of the optical parameters of the primary mirror body, the distribution mode of the reinforcing rib, the support point position and the size of the cone sleeve, and the calculation of the interval distances of the reinforcing rib and the cutting edge angle, comprises: calculating the interval distances of the reinforcing rib through a first surface shape evaluation function; and calculating the cutting edge angle through a second surface shape evaluation function; The interval distance is defined as , the first surface shape evaluation function is , and is represented as: In the formula, with Plot the first surface shape fitting curve using the x-axis as the x-axis and the RMS values ​​of the surface shape under gravity in the X, Y, and Z directions as the y-axis. , , These represent the fitted curves of the first surface shape, respectively. Curve functions in the X, Y, and Z directions, As a weighting factor, By solving the first surface evaluation function The minimum value can be used to obtain the spacing of the reinforcing ribs. ; The edge cut angle is defined as , and the second surface shape evaluation function is The second surface shape evaluation function is represented as In the formula, the As the horizontal axis, the corresponding mirror surface shape RMS value is taken as the vertical coordinate to draw a second surface shape fitting curve graph, 、 、 The second surface shape fitting curve graph is respectively The curve function in X, Y, Z directions, The weighting factor, The cutting edge angle can be obtained by solving the minimum value of the second surface shape evaluation function .

2. The mirror design method of claim 1, wherein, the optical parameters of the primary mirror body comprise an aperture and a diameter of a central obscuration, the distribution mode of the reinforcing rib is triangular, and the support point position is a position of intersection of the reinforcing ribs, and is distributed in a 120° central symmetry around a center of the back of the primary mirror body.

3. The mirror design method of claim 1, wherein, the performing of the weight reduction processing on the initial version of the primary mirror based on the cutting edge angle, and the performing of the enhancement processing on the initial version of the primary mirror after the weight reduction, to obtain the lightweight primary mirror, comprises: performing lightweight cutting edge processing on the initial version of the primary mirror along an extension direction of the reinforcing rib according to the cutting edge angle; performing flanging processing on the reinforcing rib in a non-cutting edge region of the initial version of the primary mirror after the cutting edge processing, and designing lightweight holes at positions with a thickness exceeding a preset thickness threshold, to form the lightweight primary mirror.

4. The mirror design method of claim 1, wherein, the support position of the cone sleeve should be on a same numerical plane as a center of mass of the lightweight primary mirror.

5. The mirror design method of claim 1, wherein, The determination of the flexible joint as a three-prong flexible joint, the determination of the angle between the upper flexible prong of the flexible joint and the line connecting the flexible joint and the center of the primary mirror and the angle between the lower flexible prong of the flexible joint and the line connecting the flexible joint and the center of the primary mirror through simulation analysis, and the determination of the width of the first flexible joint groove of the upper flexible prong, the third surface shape evaluation function is used to determine the width of the first flexible joint groove of the upper flexible prong, the width of the first flexible joint groove is defined as , the third surface shape evaluation function is , and is expressed as: In the formula, with As the horizontal axis, the surface shape RMS values of the surface shape under four working conditions of X, Y, Z and forced displacement 0.01 mm are taken as the vertical coordinates to draw a third surface shape fitting curve graph, , , , respectively represent the curve function of X, Y, Z and forced displacement, , is a weighting factor, The values of 0.2, 0.2, 0.2, 0.4 respectively, by solving the minimum value of the third surface shape evaluation function The width of the first flexible joint groove , and Take the multiple of 0.

1.

6. A mirror, characterized by The main mirror is lightened, the taper sleeve is installed in the support hole, and the flexible joint is installed in the taper sleeve.

7. The mirror of claim 6, wherein The lightened main mirror includes a main mirror body and a reinforcing rib arranged at the back of the main mirror body, the center of the main mirror body is provided with a through hole, the back of the main mirror body is provided with a support hole and a lightened hole, the main mirror body is provided with a cut edge bevel, the taper sleeve is installed in the support hole, and the flexible joint is installed in the taper sleeve. The flexible joint includes a first circular ring, a second circular ring, an intermediate column, an upper flexible claw and a lower flexible claw, the upper flexible claw is arranged in three, the upper flexible claws are uniformly arranged on the upper part of the intermediate column along the circumference of the intermediate column, the top edge of the upper flexible claw extends upwardly to have an L-shaped connecting portion, the L-shaped connecting portion is connected with the first circular ring, the upper flexible claw is provided with oppositely arranged first and second flexible joint grooves, the first and second flexible joint grooves are arranged in an L shape, the first and second flexible joint grooves are arranged in an axial direction and are not staggered, the lower flexible claw is arranged in three, the lower flexible claws are uniformly arranged on the lower part of the intermediate column along the circumference of the intermediate column, and the bottom edge of the lower flexible claw is provided with a stepped portion, and the stepped portion is connected with the top and inner side wall of the second circular ring. The clear aperture is 610 mm, the diameter of the through hole is 170 mm, the interval distance of the reinforcing rib is 86.5 mm, the angle between the extension line of the cut edge bevel and the back plane of the main mirror body is 25°, the maximum diameter of the taper sleeve is 80 mm, the minimum diameter is 74 mm, the taper is 2.37°, and the width of the first flexible joint groove is 2.0 mm.

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