Micro-stress assembly method of spider web-shaped micro-stress structure lens holder and lens

Abstract

The invention relates to a lens holder, in particular to a cobweb-shaped micro-stress structure lens holder and a micro-stress assembly method of a lens, and aims to solve the problems that an existing lens holder structure is prone to generating large concentrated stress on a bonding interface, so that the lens is deformed, and the imaging precision, stability and reliability of an optical system or assembly are affected. And even lens breakage or bonding failure can be caused in severe cases. The spider web-shaped microstress structure mirror holder comprises a mirror holder body, a center boss is arranged at the center position of the upper end of the mirror holder body, a dispensing face is arranged on the upper end face of the mirror holder body around the center boss, the dispensing face is lower than the center boss, an outer boss is arranged on the peripheral side of the dispensing face, and the outer boss and the center boss are equal in height. N radial grooves are formed in the dispensing face around the center boss, M circles of circumferential grooves are formed in the dispensing face around the center boss, N exhaust grooves are formed in the upper surface of the outer boss, and the inner ends of the N exhaust grooves correspond to the outer ends of the N radial grooves respectively.

Description

Technical Field

[0001] The invention relates to a mirror holder, in particular to a mirror holder with a spider web-shaped micro-stress structure and a micro-stress assembly method for a lens. Background Art

[0002] In optical instrument manufacturing, the structural design of the lens holder directly affects the accuracy, stress distribution and long-term stability of the optical system and components.

[0003] When bonding the lens to the traditional lens support structure, global planar bonding or rigid fixing methods are used. Due to factors such as differences in material thermal expansion coefficients, uneven adhesive layers, adhesive curing shrinkage, and residual bubbles, large concentrated stresses are easily generated at the bonding interface. Large concentrated stresses can cause lens deformation, which in turn affects the imaging accuracy, stability, and reliability of the optical system or components. In severe cases, it can even cause the lens to break or the bonding to fail. Especially in the fields of aerospace and high-end scientific research, their high-precision optical systems and components, such as aerospace optical cameras, star sensors, fast-swing mirrors, corner reflectors, etc., have strict requirements on assembly stress. Stress problems have seriously restricted the improvement of instrument performance. At present, the existing lens support structure is difficult to effectively solve the stress problem. There is an urgent need for an innovative structure to achieve micro-stress bonding of lenses. Summary of the Invention

[0004] The purpose of the present invention is to solve the technical problem that the existing mirror holder structure is prone to generate large concentrated stress at the bonding interface, causing deformation of the lens, thereby affecting the imaging accuracy, stability and reliability of the optical system or component, and in severe cases even causing lens rupture or bonding failure. A spider-web-shaped micro-stress structure mirror holder and a micro-stress assembly method for the lens are provided.

[0005] To achieve the above object, the technical solution adopted by the present invention is:

[0006] A spider web-shaped micro-stress structure mirror holder includes a mirror holder body; the special features of the mirror holder are:

[0007] A central boss is provided at the center of the upper end of the mirror support body;

[0008] An annular glue spotting surface is provided on the upper end surface of the mirror support body around the central boss, and the height of the glue spotting surface is lower than the upper surface of the central boss;

[0009] An outer boss is provided on the upper end surface of the mirror support body and located on the outer peripheral side of the glue dispensing surface, and the upper surface of the outer boss is at the same height as the upper surface of the central boss;

[0010] N radial grooves extending in the radial direction are provided on the dispensing surface around the central boss, the outer end of each radial groove extends to the inner edge of the outer boss, and the inner end of each radial groove extends at least to the outer edge of the central boss, wherein 6≤N≤12;

[0011] M circumferential grooves are provided on the dispensing surface around the central boss. Each circumferential groove includes N sub-circumferential grooves. Both ends of each sub-circumferential groove are connected to two adjacent radial grooves. The outer edge of the outermost circumferential groove coincides with the inner edge of the outer boss. M is a positive integer, and M ≥ 3.

[0012] N exhaust grooves are arranged on the upper surface of the outer boss around the central boss, and the inner ends of the N exhaust grooves correspond to the outer ends of the N radial grooves respectively. The outer end of each exhaust groove passes through the outer edge of the outer boss and is used to connect with the atmosphere when the lens is installed.

[0013] Furthermore, the adhesive spotting surface is a concentric ring structure, and the height difference between the upper surface of the central boss and the adhesive spotting surface is defined as H, the outer diameter of the adhesive spotting surface is Dd, and the diameter of the bonded lens is D0;

[0014] Then: 0.1mm≤H≤0.2mm, 0.65×D0≤Dd≤0.85×D0; the tolerance of H is 0.005mm.

[0015] Furthermore, the width of the radial groove is defined as W1, and the distance from the bottom surface of the radial groove to the upper surface of the central boss is defined as D1. Then, 1.5×H≤D1≤2.5×H, 1.5×H≤W1≤2.5×H;

[0016] Define the width of the circumferential groove as W2, and the distance from the bottom of the circumferential groove to the upper surface of the center boss as D2, then 1.5×H≤D2≤2.5×H, 1.5×H≤W2≤2.5×H;

[0017] Define the centerline distance between two adjacent circumferential grooves as Y, then 4mm≤Y≤8mm.

[0018] Furthermore, the depth of the exhaust groove is defined as D3 and the width as W3;

[0019] D1=D2=D3, W1=W2=W3.

[0020] Furthermore, the N exhaust grooves extend radially and divide the upper surface of the outer boss into N first positioning surfaces; the N radial grooves are evenly distributed with the axis of the central boss as the center of symmetry, and the inner end of each radial groove extends to the center of the central boss, and the N radial grooves divide the upper surface of the central boss into N second positioning surfaces; the height difference between any two surfaces of all first positioning surfaces and second positioning surfaces is less than or equal to 0.005mm.

[0021] Furthermore, the outer diameter Dd of the glue spot surface is 0.85 times the diameter D0 of the bonded lens; the surface roughness of the glue spot surface is Ra6.3μm; N=6, M=3; H=0.15mm;

[0022] The outer bottom of the mirror holder body protrudes outward to form a flange, and four flange mounting holes are evenly distributed on the flange with the axis of the central boss as the symmetrical center.

[0023] Furthermore, the mirror holder body is made of aluminum-based silicon carbide or Invar material;

[0024] A NiTi film is provided on the dispensing surface.

[0025] At the same time, the present invention also provides a micro-stress assembly method for lenses, which is based on the above-mentioned spider web-shaped micro-stress structure lens holder and is special in that it includes the following steps:

[0026] S1. Preparation of NiTi thin film

[0027] S1.1, magnetron sputtering: deposit 5-10 μm NiTi film on the dispensing surface;

[0028] S1.2, surface treatment: The NiTi film prepared in step S1.1 is treated with oxygen plasma to activate the NiTi film;

[0029] S2. Apply structural adhesive

[0030] S2.1. Glue mixing: Prepare the structural adhesive and stir under vacuum to eliminate bubbles;

[0031] S2.2, Glue application: Apply glue on the glue-applying surface, ensuring that the glue completely covers the glue-applying surface. The initial glue-applying thickness is 0.25-0.40mm.

[0032] S3. Positioning

[0033] Place the lens to be bonded on the glue on the glue spotting surface, and after calibrating the center position of the lens to be bonded, place the counterweight block on the lens to be bonded and apply pressure evenly to ensure that the lens to be bonded is in full contact with the upper surfaces of the central boss and the outer boss;

[0034] S4. Curing stress control

[0035] S4.1. Pre-curing: Place the product in a pre-set temperature environment and allow it to stand for a pre-set time to set;

[0036] S4.2. Heating trigger: Maintain the temperature at 54-56°C for 2-4 hours to allow the NiTi film to deform and compensate for stress;

[0037] S4.3. Cooling: Cool naturally to room temperature to complete the micro-stress assembly of the lens.

[0038] Furthermore, in step S2.2, when applying glue to the glue-dispensing surface, a curved plate is used to apply glue from the center to the edge of the glue-dispensing surface in a scraping manner, and the amount of glue entering the radial groove and the circumferential groove is controlled to not exceed 25% of their respective spaces;

[0039] Step S4.2 is specifically as follows: maintaining the temperature at 55° C. for 3 hours to allow the NiTi film to deform and compensate for the stress.

[0040] Furthermore, step S1.1 is specifically to use a magnetron sputtering coating machine to coat a 5-10 μm NiTi film on the dispensing surface by magnetron sputtering. The working parameters of the magnetron sputtering coating machine are required to be 180W and vacuum degree ≤1×10-3P. a , temperature 200℃;

[0041] In step S1.2, the oxygen plasma treatment time is 8 minutes;

[0042] Step S2.1 specifically comprises: preparing 3M EC2216 epoxy structural adhesive at a weight ratio of 7:5 between adhesive A and adhesive B, adding 0.5% fumed silica (based on the total weight of the adhesive), and stirring under vacuum for at least 3 minutes to eliminate bubbles;

[0043] In step S3, after the lens to be bonded is in complete contact with the upper surfaces of the central boss and the outer boss, the thickness of the glue layer on the glue-dispensing surface is 0.15 mm;

[0044] In step S4.1, the preset temperature is 25°C and the preset time is 2 hours.

[0045] Compared with the prior art, the present invention has the following beneficial technical effects:

[0046] 1. The spider-web-like micro-stress structure of the present invention is provided with N radial grooves and M circumferential grooves, so that the upper end surface of the mirror holder body has a spider-web-like structure, forming multiple fan-shaped stress dispersion units. The geometric shape balances the shear force and tensile force on the lens, effectively absorbing and evenly distributing the stress generated by factors such as glue curing shrinkage and differences in material thermal expansion coefficients, achieving micro-stress bonding of the lens, preventing deformation or cracking of the lens due to stress, and ensuring that the original optical accuracy and performance of the lens are not affected.

[0047] 2. The spider-web-shaped micro-stress structure of the mirror holder of the present invention forms a flow guide system through the glue point surface and the radial grooves and circumferential grooves, which can effectively discharge glue, prevent uneven accumulation of glue layers, and achieve glue quantity control;

[0048] 3. The spider-web-shaped micro-stress structure mirror holder of the present invention is provided with exhaust grooves to discharge air in the bonding area during bonding, thereby preventing the formation of bubbles, improving the density of the bonding interface, and thus improving the bonding reliability;

[0049] 4. The spider-web-shaped micro-stress structure lens holder of the present invention provides a central boss and an outer boss to mechanically limit the lens, thereby achieving precise positioning of the lens, ensuring uniform thickness of the adhesive layer, and guaranteeing bonding strength.

[0050] 5. The spider-web-shaped micro-stress structure lens holder of the present invention can adjust the structural parameters of each part according to the size of different lenses and the requirements of the optical system. It is suitable for fixing and bonding a variety of optical lenses and has good versatility.

[0051] 6. In the spider-web-shaped micro-stress structure mirror holder of the present invention, the mirror holder body is made of aluminum-based silicon carbide or Invar material, which has high specific strength, excellent corrosion resistance and good thermal stability, and can meet the mechanical performance requirements of the mirror holder. At the same time, its thermal expansion coefficient can match that of common optical lens materials, which can reduce the stress caused by thermal expansion differences.

[0052] 7. The present invention provides a micro-stress lens assembly method, wherein the lens to be bonded is placed on the adhesive layer of the adhesive dispensing surface, uniformly pressed with a counterweight, and quickly and accurately positioned by mechanical limiters, so that the bonded lens is in full contact with the upper surfaces of the central and outer bosses. Simultaneously, the above-mentioned operation controls the adhesive layer thickness to 0.15 mm, thereby ensuring that the tilt of the bonded lens relative to the lens holder is ≤ 5 arcsec.

[0053] 8. The micro-stress assembly method of the lens of the present invention is to deposit a 5-10 μm NiTi film on the glue-dotting surface and keep it at a temperature of 54-56°C for 2-4 hours, preferably at 55°C for 3 hours. The NiTi film is deformed during curing, and the curing and stress compensation are completed simultaneously, avoiding the generation of secondary stress. The NiTi film actively compensates and cooperates with the radial groove and circumferential groove to guide the flow, thereby realizing micro-stress assembly. The lens surface error is ≤λ / 20 (λ=632.8nm), which can meet the aerospace grade optical precision. In addition, the thermal expansion coefficient of the NiTi film (8.3×10 -6 / ℃) and optical glass (such as K9 glass about 7.1×10 -6 / ℃), the thermal stress compensation efficiency reaches 85%, and the stress fluctuation is less than 5% in the cycle from -50℃ to +120℃. In addition, the thermoelastic deformation of the NiTi film combined with the uniform heat conduction of the spider web structure (temperature difference <2℃) can improve the uniformity of stress distribution by 60%;

[0054] 9. The micro-stress assembly method of the lens of the present invention applies glue by scraping glue from the center of the glue-dotting surface to the edge through a curved plate, and reserves at least 75% of the radial groove and circumferential groove space for air and glue removal, which can improve the uniformity of the glue layer by 40%. The glue-free design on the central boss and the outer boss supports non-destructive disassembly of the lens, shortens the maintenance time by 60%, and achieves a lens reuse rate of 90%. In addition, manual glue application is easy to operate, with less glue waste, suitable for small-batch production, and the equipment cost is reduced by 70% compared with the automated solution, and the unit cost is reduced by 35%. BRIEF DESCRIPTION OF THE DRAWINGS

[0055] Figure 1 This is a schematic diagram of the three-dimensional structure of an embodiment of a spider web-shaped micro-stress structure mirror holder of the present invention;

[0056] Figure 2 This is a schematic top view of a spider web-shaped micro-stress structure mirror holder embodiment of the present invention;

[0057] Figure 3 for Figure 2 AA section view in the figure;

[0058] Figure 4 for Figure 3 Enlarged view of point C in the figure;

[0059] Figure 5 for Figure 2 BB section view in the figure;

[0060] Figure 6 for Figure 5 Enlarged view of point D in .

[0061] The following are the descriptions of the reference numerals:

[0062] 1-mirror support body, 11-flange, 2-center boss, 3-glue surface, 4-outer boss, 41-first positioning surface, 5-radial groove, 6-circumferential groove, 7-exhaust groove, 8-flange mounting hole. DETAILED DESCRIPTION

[0063] To make the objects, advantages and features of the present invention more clear, the spider web-shaped micro-stress structure mirror holder and the micro-stress assembly method of the lens proposed by the present invention are further described in detail below with reference to the accompanying drawings and specific embodiments.

[0064] In the description of the present invention, it should be noted that the terms “first” and “second” are only used for descriptive purposes and should not be understood as indicating or implying relative importance.

[0065] Reference Figure 1The spiderweb-shaped microstress structure mirror holder of the present invention includes a mirror holder body 1, which is made of aluminum-based silicon carbide or Invar (4J32) steel and machined using a CNC milling machine and lathe. Made of a rigid material with high specific strength, excellent corrosion resistance, and good thermal stability, the mirror holder body 1 meets the mechanical performance requirements of the mirror holder. Its thermal expansion coefficient matches that of common optical lens materials, reducing stress caused by thermal expansion differences.

[0066] like Figure 1 and Figure 2 As shown, in order to facilitate a rigid and stable connection with other optical instruments or brackets, the outer bottom of the mirror holder body 1 protrudes outward to form a flange 11, and four flange mounting holes 8 are evenly distributed on the flange 11 with the axis of the central boss 2 as the symmetrical center. The flange mounting holes 8 are stepped holes, and screws or other fasteners can be used to make the mirror holder body 1 and other optical instruments or brackets rigid and stable.

[0067] like Figure 1 and Figure 2 As shown, a center boss 2 is provided at the center of the upper end of the mirror holder body 1. An annular adhesive spot surface 3 is provided on the upper end surface of the mirror holder body 1 around the center boss 2, and the height of the adhesive spot surface 3 is lower than the upper surface of the center boss 2. An outer boss 4 is provided on the upper end surface of the mirror holder body 1 and located on the outer peripheral side of the adhesive spot surface 3, and the upper surface of the outer boss 4 is at the same height as the upper surface of the center boss 2. The center boss 2 and the outer boss 4 are both supported below the lens to be bonded. Through mechanical limiting, the lens can be precisely positioned, the thickness of the adhesive layer can be precisely controlled, the thickness of the adhesive layer can be ensured to be uniform, and the bonding strength can be guaranteed. In addition, the center boss 2 is supported directly below the center of the bonded lens and is not glued here, which can completely avoid stress in the center of the lens. The concave design of the adhesive spot surface 3 also makes it difficult for the glue to overflow during application and bonding, and will not contaminate the mirror surface. During solidification, a uniform adhesive layer of a certain thickness is formed, reducing the stress caused by glue accumulation.

[0068] The thickness of the adhesive layer should not be too thin, otherwise it will affect the bonding strength between the lens holder and the lens. The thickness of the adhesive layer should not be too thick, otherwise it will produce great bonding stress. Figure 3 and Figure 4As shown, the height difference between the upper surface of the center boss 2 and the adhesive surface 3 is defined as H, then 0.1mm≤H≤0.2mm, the tolerance of H is 0.005mm, and H in this embodiment is 0.15mm. The adhesive surface 3 is a concentric ring structure. The outer diameter of the adhesive surface 3 should not be too small, otherwise it will result in insufficient bonding area between the lens holder and the lens, and the bonding will be unstable. The outer diameter of the adhesive surface 3 should not be too large, otherwise it will generate more bonding stress. The outer diameter of the adhesive surface 3 is defined as Dd and the diameter of the bonded lens is defined as D0. Then 0.65×D0≤Dd≤0.85×D0. In this embodiment, the outer diameter Dd of the adhesive surface 3 is 0.85 times the diameter D0 of the bonded lens, which can increase the bonding strength by 20% (shear strength ≥22MPa). To ensure the bonding quality, the surface roughness of the adhesive surface 3 is Ra6.3μm.

[0069] like Figure 2 、 Figure 3 、 Figure 4 、 Figure 5 and Figure 6 As shown, N radial grooves 5 extending radially are provided on the dispensing surface 3 around the central boss 2, N=6, and the 6 radial grooves 5 are evenly distributed with the axis of the central boss 2 as the center of symmetry. The outer end of each radial groove 5 extends to the inner edge of the outer boss 4, and the inner end of each radial groove 5 extends at least to the outer edge of the central boss 2. M circles of circumferential grooves 6 are provided around the central boss 2 on the dispensing surface 3, M=3, and each circle of circumferential grooves 6 includes 6 sub-circumferential grooves. The two ends of each sub-circumferential groove are respectively connected to the two adjacent radial grooves 5, and the outer edge of the outermost circle of circumferential grooves 6 coincides with the inner edge of the outer boss 4. The 6 radial grooves 5 and the 3 circles of circumferential grooves 6 divide the dispensing surface 3 into 18 fan-shaped sub-dispensing surfaces, and a NiTi film is provided on the sub-dispensing surface. By providing N radial grooves 5 and M circles of circumferential grooves 6 on the dispensing surface 3, and making these grooves spider-shaped The spiderweb-like uniform distribution not only guides the discharge of excess glue and air during the glue coating and curing process, avoiding uneven glue layers and residual air inside, but also provides a certain amount of space for the glue and material when they expand or contract, thereby alleviating the stress caused by the shrinkage of the glue and material; six exhaust grooves 7 are provided on the upper surface of the outer boss 4 around the central boss 2. The six exhaust grooves 7 extend radially, and the inner ends of the six exhaust grooves 7 correspond to the outer ends of the six radial grooves 5 respectively. The outer end of each exhaust groove 7 penetrates the outer edge of the outer boss 4, allowing the lens to be connected to the atmosphere during installation. By providing the exhaust grooves 7 at the ends of the radial grooves 5 and allowing the outer ends of the exhaust grooves 7 to penetrate the lens holder body 1 and connect to the atmosphere, air in the bonding area can be discharged during bonding, avoiding the formation of bubbles, improving the density of the bonding interface, and thus improving the bonding reliability. In other embodiments, the value of N can also be set to 7, 8, 9, 10, 11, or 12, and the value of M can also be set to 4, 5, 6, 8, or 10, etc.

[0070] Define the width of the radial groove 5 as W1 and the distance from the bottom of the radial groove 5 to the upper surface of the center boss 2 as D1, then 1.5×H≤D1≤2.5×H, 1.5×H≤W1≤2.5×H, define the width of the circumferential groove 6 as W2 and the distance from the bottom of the circumferential groove 6 to the upper surface of the center boss 2 as D2, then 1.5×H≤D2≤2.5×H, 1.5×H≤W2≤2.5×H, define the depth of the exhaust groove 7 as D3 and the width as W3, preferably D1=D2=D3, W1=W2=W3, unifying the groove size can reduce the processing cost by 25%, and is suitable for lenses with a diameter of 30-100mm. In this embodiment, D1=D2=D3=1.5H, W1=W2=W3=1.5H. The centerline distance between two adjacent circles of circumferential grooves 6 is defined as Y, and 4 mm ≤ Y ≤ 8 mm. In this embodiment, the centerline distance between two adjacent circles of circumferential grooves 6 is 6 mm.

[0071] By reasonably setting the dimensions of the radial grooves 5, circumferential grooves 6 and exhaust grooves 7, multiple groups of independent fan-shaped buffer units can be formed to achieve dual core performance improvement: stress concentration is reduced by more than 86%, and the thermal expansion difference stress absorption efficiency reaches 75%, which can adapt to aerospace-grade temperature cycles (-50℃~+120℃); at the same time, the three are used for both debonding and exhaust, and the mesh channel formed effectively shortens the exhaust distance, which can quickly exhaust the air in the bonding area. The groove body diversion can also improve the uniformity of the glue layer.

[0072] like Figure 2 As shown, the inner end of each radial groove 5 extends to the center of the central boss 2. This arrangement not only facilitates processing but also reduces the stress generated when bonding the lens holder to the lens. The six exhaust grooves 7 divide the upper surface of the outer boss 4 into six first positioning surfaces 41, and the six radial grooves 5 divide the upper surface of the central boss 2 into six second positioning surfaces. To achieve precise positioning of the lens and ensure the thickness of the adhesive layer during bonding, the height difference between any two of the first positioning surfaces 41 and the second positioning surfaces is less than or equal to 0.005mm. The use of submicron positioning surfaces (height difference ≤ 0.005mm) can ensure the accuracy of lens installation.

[0073] The spiderweb-like micro-stress structure of the present invention effectively disperses and releases stress generated by temperature fluctuations during bonding and use, enabling micro-stress assembly, improving bonding reliability and stability, and ensuring the imaging accuracy of optical systems or optical components. This structure is suitable for optical systems or components requiring high stability and reliability, such as those in aerospace, high-end scientific research, and other fields that require strict assembly stress. Furthermore, the structure can be adjusted to suit the different lens sizes and optical system requirements, making it suitable for the fixed bonding of a variety of optical lenses, demonstrating its versatility.

[0074] The micro-stress assembly method of the lens of the present invention is based on the above-mentioned spider web-shaped micro-stress structure lens holder, and comprises the following steps:

[0075] S1. Preparation of NiTi thin film

[0076] S1.1. Magnetron sputtering: Use a magnetron sputtering coating machine to coat a 5-10μm NiTi film on the dispensing surface 3 by magnetron sputtering. The working parameters of the magnetron sputtering coating machine are required to be 180W and vacuum degree ≤1×10-3P. a , temperature 200℃;

[0077] S1.2. Surface treatment: The NiTi film prepared in step S1.1 was treated with oxygen plasma for 8 minutes to activate the NiTi film;

[0078] S2. Apply structural adhesive

[0079] S2.1. Glue Mixing: Prepare 3M EC2216 structural epoxy adhesive at a weight ratio of 7:5 between adhesive A and adhesive B. Add 0.5% fumed silica (total weight of adhesive) and stir under vacuum for at least 3 minutes to eliminate air bubbles.

[0080] S2.2. Gluing: Apply glue to the glue-dispensing surface 3, ensuring that the glue completely covers the glue-dispensing surface 3. The initial glue thickness is 0.25-0.40 mm. When applying glue to the glue-dispensing surface 3, use a curved plate to apply glue from the center of the glue-dispensing surface 3 toward the edge by scraping. Ensure that the amount of glue entering the radial groove 5 and the circumferential groove 6 does not exceed 25% of their respective spaces.

[0081] S3. Positioning

[0082] Place the lens to be bonded on the glue on the glue-dispensing surface 3 and calibrate the center position of the lens to be bonded. Then, place a counterweight on the lens to be bonded and apply uniform pressure to ensure that the lens to be bonded is in full contact with the upper surfaces of the central boss 2 and the outer boss 4. After the lens to be bonded is in full contact with the upper surfaces of the central boss 2 and the outer boss 4, the thickness of the glue layer on the glue-dispensing surface 3 is 0.15 mm.

[0083] S4. Curing stress control

[0084] S4.1. Pre-curing: Place the film at 25°C for 2 hours to set.

[0085] S4.2. Heating trigger: Maintain the temperature at 55°C for 3 hours to allow the NiTi film to deform and compensate for stress;

[0086] S4.3. Cooling: Cool naturally to room temperature to complete the micro-stress assembly of the lens.

[0087] Conventional methods rely on adhesive layer thickness to control lens position, resulting in an error of ±0.10mm and being easily affected by the fluidity of the adhesive, leading to lens tilt of 20 arc-seconds. In contrast, the present invention's micro-stress lens assembly method places the lens to be bonded onto the adhesive layer on the adhesive-dispensing surface, applies uniform pressure using a counterweight, and achieves rapid and precise positioning with the help of mechanical limiters, ensuring full contact between the bonded lens and the upper surfaces of the central boss 2 and the outer boss 4. Simultaneously, these operations control the adhesive layer thickness to 0.15mm±0.005mm, ensuring that the bonded lens tilts ≤5 arc-second relative to the lens holder.

[0088] Compared with the conventional method of flat glue injection, the micro-stress assembly method of the lens of the present invention adopts a curved plate to apply glue from the center of the glue spot surface 3 to the edge by scraping glue, and reserves at least 75% of the radial groove 5 and the circumferential groove 6 space for air and glue removal, which can improve the uniformity of the glue layer by 40%.

[0089] The present invention's low-stress lens assembly method boasts strong process compatibility, utilizes manual glue application, minimizes glue waste, is simple to operate, and is suitable for small-batch production. Compared to automated solutions, the equipment cost is reduced by 70%, and the unit cost is reduced by 35%. The glue-free design of the central boss 2 and the outer boss 4 allows for non-destructive lens disassembly (after softening the glue layer by heating it to 80°C to 120°C, the lens can be removed from the lens holder). This reduces maintenance time by 60%, and increases the lens reuse rate to 90%.

[0090] Conventional methods only use temperature curing, rely on the elasticity of the adhesive layer or the passive stress dispersion of the lens support structure, which cannot offset the curing shrinkage and thermal stress. The residual stress is ≥0.02MPa, resulting in a lens surface error ≥λ / 8 (λ=632.8nm). In contrast, the micro-stress assembly method of the lens of the present invention deposits a 5-10μm NiTi film on the adhesive surface 3 and maintains it at a temperature of 54-56℃ for 2-4 hours to trigger the deformation of the NiTi film. Preferably, the NiTi film is triggered when it is maintained at a temperature of 55℃ for 3 hours to trigger the deformation of the NiTi film. The NiTi film (5-10μm) actively generates 0.03-0.05MPa compressive stress through the 55℃ phase transition, which can compensate for the shrinkage of the adhesive layer (the shrinkage rate is reduced from 0.5% to 0.2%). , which improves the stress dispersion efficiency by 50%, completes the curing and stress compensation simultaneously, avoids the generation of secondary stress, and cooperates with the radial groove 5 and the circumferential groove 6 for diversion. After the NiTi film is actively compensated, the residual stress is ≤0.005MPa, and the lens surface error is ≤λ / 20 (λ=632.8nm), which can meet the aerospace-grade optical precision. For example, the surface accuracy RMS of the fast-swing mirror is required to be ≤λ / 30 (λ=632.8nm). The phase change stress compensation is superimposed on the geometric buffer, and the total stress compensation efficiency is 92%.

[0091] Compared with the conventional method, which relies on the glue layer to buffer the thermal expansion difference, the compensation efficiency is less than 30%, and the thermal expansion and contraction of the material can easily lead to lens cracking. The micro-stress assembly method of the lens of the present invention has a NiTi film thermal expansion coefficient (8.3×10 -6 / ℃) and optical glass (such as K9 glass about 7.1×10 -6 / ℃), with a thermal stress compensation efficiency of 85%. Stress fluctuations during the -50℃ to +120℃ cycle are less than 5%. In addition, the thermoelastic deformation of the NiTi film combined with the uniform heat conduction of the spider-web structure (temperature difference <2℃) can improve the uniformity of stress distribution by 60%.

[0092] Compared with conventional methods, the lens is easy to crack under vibration impact, with a cracking probability of 35%. The micro-stress assembly method of the lens of the present invention can absorb mechanical energy. After random vibration with a total root mean square acceleration of 17.3 grms (frequency 20-2000 Hz, power spectrum density 0.04 g 2 / Hz, in line with GJB150.16A-2009 standard), the adhesive layer has no cracks, and the lens displacement is less than 0.003mm.

[0093] The micro-stress assembly method of the lens of the present invention, through the triple innovation of "material phase change stress compensation + mechanical precision limiting + structural diversion assistance", breaks through the limitations of conventional process methods that rely on adhesive layers and structures to passively disperse stress, and achieves multi-dimensional upgrades in stress control accuracy, process flexibility and environmental adaptability. It is particularly suitable for high-end optical component fixing scenarios that are sensitive to assembly stress.

[0094] The micro-stress assembly method of the lens of the present invention can withstand a 1000g half-sine wave shock (duration 15ms, in line with the GJB150.18A-2009 standard) and a random vibration with a total root mean square acceleration of 17.3grms (frequency 20-2000Hz, power spectrum density 0.04g 2 / Hz, in line with GJB150.16A-2009 standard), and can meet aerospace stability requirements.

[0095] In other embodiments, other structural adhesives, such as DG-4, 3MDP810, and 3MDP100, may be used depending on actual bonding requirements. Accordingly, steps S2.1 and other steps may be adapted based on the other structural adhesive used. A three-dimensional coordinate measuring machine may be used to calibrate the center position of the bonded lens.

[0096] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the specific technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the present invention.

Claims

1. A spider web-shaped micro-stress structure mirror holder, comprising a mirror holder body (1); characterized in that: A central boss (2) is provided at the center of the upper end of the mirror holder main body (1); An annular glue-dispensing surface (3) is provided on the upper end surface of the mirror holder body (1) surrounding the central boss (2), and the height of the glue-dispensing surface (3) is lower than the upper surface of the central boss (2); An outer boss (4) is provided on the upper end surface of the mirror holder body (1) and on the outer peripheral side of the glue dispensing surface (3), and the upper surface of the outer boss (4) is at the same height as the upper surface of the central boss (2); N radial grooves (5) extending in the radial direction are provided on the dispensing surface (3) around the central boss (2), the outer end of each radial groove (5) extends to the inner edge of the outer boss (4), and the inner end of each radial groove (5) extends at least to the outer edge of the central boss (2), wherein 6≤N≤12; The dispensing surface (3) is provided with M circumferential grooves (6) around the central boss (2), each circumferential groove (6) includes N sub-circumferential grooves, both ends of each sub-circumferential groove are respectively connected to two adjacent radial grooves (5), and the outer edge of the outermost circumferential groove (6) coincides with the inner edge of the outer boss (4), wherein M is a positive integer, and M≥3; N exhaust grooves (7) are provided on the upper surface of the outer boss (4) surrounding the central boss (2), the inner ends of the N exhaust grooves (7) respectively corresponding to the outer ends of the N radial grooves (5), and the outer end of each exhaust groove (7) passes through the outer edge of the outer boss (4) for communication with the atmosphere when the lens is installed.

2. The spider web-shaped micro-stress structure mirror holder according to claim 1, characterized in that: The glue spot surface (3) is a concentric ring structure, and the height difference between the upper surface of the central boss (2) and the glue spot surface (3) is defined as H, the outer diameter of the glue spot surface (3) is Dd, and the diameter of the bonded lens is D0; Then: 0.1mm≤H≤0.2mm, 0.65×D0≤Dd≤0.85×D0; the tolerance of H is 0.005mm.

3. The spider web-shaped micro-stress structure mirror holder according to claim 2, characterized in that: The width of the radial groove (5) is defined as W1, and the distance from the bottom surface of the radial groove (5) to the upper surface of the central boss (2) is defined as D1, then 1.5×H≤D1≤2.5×H, 1.5×H≤W1≤2.5×H; The width of the circumferential groove (6) is defined as W2, and the distance from the bottom surface of the circumferential groove (6) to the upper surface of the central boss (2) is defined as D2, then 1.5×H≤D2≤2.5×H, 1.5×H≤W2≤2.5×H; The centerline spacing between two adjacent circles of the circumferential grooves (6) is defined as Y, and 4mm≤Y≤8mm.

4. The spider web-shaped micro-stress structure mirror holder according to claim 3, characterized in that: The exhaust groove (7) is defined as having a depth of D3 and a width of W3; Said D1=D2=D3, W1=W2=W3.

5. The spider web-shaped micro-stress structure mirror holder according to claim 4, characterized in that: The N exhaust grooves (7) all extend radially and divide the upper surface of the outer boss (4) into N first positioning surfaces (41); the N radial grooves (5) are evenly distributed with the axis of the central boss (2) as the symmetrical center, and the inner end of each radial groove (5) extends to the center of the central boss (2), and the N radial grooves (5) divide the upper surface of the central boss (2) into N second positioning surfaces; the height difference between any two of the first positioning surfaces (41) and the second positioning surfaces is less than or equal to 0.005 mm.

6. The spider web-shaped micro-stress structure mirror holder according to claim 5, characterized in that: The outer diameter Dd of the glue-dotting surface (3) is 0.85 times the diameter D0 of the bonded lens; the surface roughness of the glue-dotting surface (3) is Ra6.3 μm; N=6, M=3; H=0.15 mm; The outer bottom of the mirror holder body (1) protrudes outward to form a flange (11), and the flange (11) is evenly distributed with four flange mounting holes (8) with the axis of the central boss (2) as the symmetrical center.

7. The spider web-shaped micro-stress structure mirror holder according to any one of claims 1 to 6, characterized in that: The mirror holder body (1) is made of aluminum-based silicon carbide or Invar material; A NiTi film is provided on the glue dispensing surface (3).

8. A micro-stress assembly method for lenses, based on the spider web-shaped micro-stress structure lens holder according to any one of claims 1 to 7, characterized in that: The following steps are involved: S1. Preparation of NiTi thin film S1.1, magnetron sputtering: depositing a 5-10 μm NiTi film on the dispensing surface (3); S1.2, surface treatment: The NiTi film prepared in step S1.1 is treated with oxygen plasma to activate the NiTi film; S2. Apply structural adhesive S2.

1. Glue mixing: Prepare the structural adhesive and stir under vacuum to eliminate bubbles; S2.2, glue application: Apply glue on the glue application surface (3), ensuring that the glue completely covers the glue application surface (3). The initial glue application thickness is 0.25-0.40 mm; S3. Positioning The lens to be bonded is placed on the glue of the glue spotting surface (3), and after calibrating the center position of the lens to be bonded, a counterweight is placed on the lens to be bonded and uniformly pressurized so that the lens to be bonded is in complete contact with the upper surfaces of the central boss (2) and the outer boss (4); S4. Curing stress control S4.

1. Pre-curing: Place the product in a pre-set temperature environment and allow it to stand for a pre-set time to set; S4.

2. Heating trigger: Maintain the temperature at 54-56°C for 2-4 hours to allow the NiTi film to deform and compensate for stress; S4.

3. Cooling: Cool naturally to room temperature to complete the micro-stress assembly of the lens.

9. The micro-stress assembly method of a lens according to claim 8, characterized in that: In step S2.2, when applying glue to the glue spot surface (3), a curved plate is used to apply glue from the center to the edge of the glue spot surface (3) in a scraping manner, and the amount of glue entering the radial groove (5) and the circumferential groove (6) is controlled to not exceed 25% of their respective spaces; Step S4.2 is specifically as follows: maintaining the temperature at 55° C. for 3 hours to allow the NiTi film to deform and compensate for the stress.

10. The micro-stress assembly method of a lens according to claim 9, characterized in that: Step S1.1 is specifically to use a magnetron sputtering coating machine to coat a 5-10 μm NiTi film on the dispensing surface (3) by magnetron sputtering. The working parameters of the magnetron sputtering coating machine are required to be 180W and vacuum degree ≤1×10-3P. a , temperature 200℃; In step S1.2, the oxygen plasma treatment time is 8 minutes; Step S2.1 specifically comprises: preparing 3M EC2216 epoxy structural adhesive at a weight ratio of 7:5 between adhesive A and adhesive B, adding 0.5% fumed silica (based on the total weight of the adhesive), and stirring under vacuum for at least 3 minutes to eliminate bubbles; In step S3, after the lens to be bonded is in complete contact with the upper surfaces of the central boss (2) and the outer boss (4), the thickness of the glue layer on the glue-dispensing surface (3) is 0.15 mm; In step S4.1, the preset temperature is 25°C and the preset time is 2 hours.

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