Multi-leaf support configuration and system with stress dispersion and directional heat conduction function

Abstract

The application provides a multi-elastic piece supporting structure and system with stress dispersion and directional heat conduction functions, and relates to the optical technology field, which comprises a ring-shaped mirror frame and a plurality of elastic pieces; a gradual transition area is arranged between the root fixed section and the elastic deformation section; a stress release hole is arranged in the middle area of the elastic deformation section, and the stress release hole is in an elliptical shape; the elastic piece comprises an elastic metal base layer, a first heat conduction layer and a second heat conduction layer which are respectively compounded on the upper and lower two side surfaces of the elastic metal base layer; a heat conduction adhesive layer is arranged between the supporting section and the lens supporting surface; an annular heat conduction collecting ring is fixedly arranged on the inner side of the ring-shaped mirror frame, and the annular heat conduction collecting ring is in heat conduction connection with the root fixed section of each elastic piece; the application meets the requirements of the compact structure and the heat management efficiency of the precise optical system without the need of additionally increasing a heat dissipation module, and helps to improve the long-term stability of the optical surface shape of the lens.

Description

Technical Field

[0001] This invention relates to the field of optical technology, and in particular to a multi-spring support configuration and system with stress dispersion and directional heat conduction functions. Background Technology

[0002] In precision optical measurement and imaging systems, the mechanical and thermal stability of the lens support structure directly affects the imaging quality of the optical system. Existing technologies often employ a circumferentially distributed multi-spring support structure, with the spring roots fixed to the lens frame and the support ends glued to the lens. However, this structure reveals several problems in practical applications: Firstly, when subjected to mechanical loads or thermal mismatch stress caused by temperature changes, stress concentration easily forms at the connection between the spring roots and the lens frame, as well as at the elastic arm. Long-term operation may lead to microcracks or plastic deformation, affecting the long-term stability of the support and the lens's surface shape retention capability. Secondly, these springs are typically made of a single stainless steel material with low thermal conductivity, making it difficult to effectively conduct the heat generated by the lens during operation to the lens frame, easily causing localized temperature rise in the lens, which in turn leads to thermal deformation and wavefront distortion. Furthermore, in existing support designs, mechanical support and thermal management are often considered as independent subsystems, lacking a solution that can integrate stress-dispersing and heat-conducting structures. Summary of the Invention

[0003] To address the aforementioned technical problems, the technical solution adopted by this invention is as follows:

[0004] According to a first aspect of this application, a multi-sheet support configuration with stress dispersion and directional heat conduction functions is provided, comprising:

[0005] A ring-shaped lens frame, and a number of spring pieces spaced circumferentially on the inner side of the ring-shaped lens frame; each spring piece includes an integrally connected root fixing section, an elastic deformation section and a support section; the root fixing section is fixedly connected to the ring-shaped lens frame, the support section is used to bond to the lens support surface, and the elastic deformation section is connected between the root fixing section and the support section.

[0006] A gradual transition zone is provided between the root fixing section and the elastic deformation section, and the cross-sectional width of the gradual transition zone decreases from the root fixing section to the elastic deformation section along the length direction of the spring sheet.

[0007] The middle region of the elastic deformation section is provided with a stress relief hole, which is elliptical and the major axis of the stress relief hole is set along the length of the elastic piece; the thickness of the elastic deformation section varies in gradient along the length direction, and the thickness at the root is greater than the thickness at the end.

[0008] The spring includes an elastic metal base layer and a first heat-conducting layer and a second heat-conducting layer respectively bonded to the upper and lower surfaces of the elastic metal base layer. The elastic metal base layer is made of stainless steel, and the first and second heat-conducting layers are made of copper or copper alloy.

[0009] A thermally conductive adhesive layer is provided between the support section and the lens support surface to reduce contact thermal resistance and guide heat into the spring sheet.

[0010] An annular heat-conducting collection ring is fixedly installed on the inner side of the annular frame. The annular heat-conducting collection ring is heat-conductingly connected to the root fixed section of each spring piece, and is used to collect the heat conducted by each spring piece and transfer it outward to the annular frame.

[0011] According to another aspect of this application, an optical system is also provided, including an optical lens and a multi-spring support configuration with stress dispersion and directional heat conduction functions as described in the first aspect, wherein the side support surface of the optical lens is bonded and fixed to the support section of the spring through the thermally conductive adhesive layer, and the thermally conductive adhesive layer completely covers the mating gap between the support section and the lens support surface.

[0012] The present invention has at least the following beneficial effects:

[0013] The multi-spring support configuration of this invention, featuring stress dispersion and directional heat conduction, incorporates a gradually decreasing cross-sectional width transition zone, an elliptical stress relief hole in the center, and an elastic deformation section with varying thickness on each spring. These three elements work together to effectively reduce the root stress concentration factor and suppress localized accumulation of thermal mismatch stress, ensuring the spring maintains good fatigue resistance during long-term use and reducing uneven constraints on the lens surface. Simultaneously, at the material level, the spring employs a multi-layer structure with a stainless steel base layer and copper or copper alloy layers on both sides. Combined with a thermally conductive adhesive layer at the support surface and an annular heat-collecting ring inside the lens frame, this constructs a low-thermal-resistance directional heat conduction path from the lens through the spring composite layer and the collecting ring to the lens frame, effectively reducing the temperature rise of the lens under steady-state operation. This structure integrates stress dispersion and heat conduction functions into a single unit, meeting the requirements of precision optical systems for structural compactness and thermal management efficiency without the need for additional heat dissipation modules, thus contributing to improved long-term stability of the lens's optical surface shape. Attached Figure Description

[0014] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0015] Figure 1This is a schematic diagram of the overall structure of the multi-spring support configuration provided in an embodiment of the present invention;

[0016] Figure 2 This is a schematic diagram of the structure of a single spring piece provided in an embodiment of the present invention;

[0017] Figure 3 This is a schematic diagram of the composite layer structure of a single spring sheet provided in an embodiment of the present invention;

[0018] Figure 4 This is a partially enlarged schematic diagram of the stress relief hole of the spring sheet provided in an embodiment of the present invention;

[0019] Figure 5 This is a schematic diagram of the heat conduction path provided in an embodiment of the present invention. Detailed Implementation

[0020] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0021] It should be noted that, based on this disclosure, those skilled in the art will understand that one aspect described herein can be implemented independently of any other aspect, and two or more of these aspects can be combined in various ways. For example, any number of aspects set forth herein can be used to implement the device and / or practice the method. Furthermore, this device and / or practice the method can be implemented using other structures and / or functionalities besides one or more of the aspects set forth herein.

[0022] The following will refer to Figure 1 The schematic diagram of the overall structure of the multi-spring support configuration shown illustrates a multi-spring support configuration with stress dispersion and directional heat conduction functions.

[0023] This multi-sheet support configuration with stress dispersion and directional heat conduction functions includes:

[0024] A ring-shaped lens frame, and a number of spring pieces spaced circumferentially on the inner side of the ring-shaped lens frame; each spring piece includes an integrally connected root fixing section, an elastic deformation section and a support section; the root fixing section is fixedly connected to the ring-shaped lens frame, the support section is used to bond to the lens support surface, and the elastic deformation section is connected between the root fixing section and the support section.

[0025] In this embodiment, the overall structure of the multi-spring support configuration is shown in the attached figure. Figure 1As shown, it mainly includes a ring-shaped metal frame and several spring clips evenly spaced along the circumference inside the frame. In actual manufacturing, the frame can be made of stainless steel, the same material as the spring clip base, to avoid assembly deviations caused by excessive differences in the coefficients of thermal expansion between different materials. The number of spring clips can be selected according to the lens diameter and weight. For example, in typical small-diameter optical lens applications, six spring clips can be used, while in larger-diameter precision systems, the number can be increased to about twelve. The core design of this configuration is to integrate the stress dispersion mechanism and heat conduction path into a single spring clip, eliminating the need for additional heat dissipation gaskets or cooling pipes. Therefore, the overall axial dimensions are compact, making it suitable for space-constrained precision optical packaging environments.

[0026] A gradual transition zone is provided between the root fixing section and the elastic deformation section, and the cross-sectional width of the gradual transition zone decreases from the root fixing section to the elastic deformation section along the length direction of the spring sheet.

[0027] Specifically, regarding the structure of each shrapnel, such as Figure 2 As shown, the spring is integrally connected longitudinally to form three parts: a root fixing section, an elastic deformation section, and a support section. The root fixing section is where the spring is fixedly connected to the side wall of the lens frame. In actual assembly, this part is fitted to the lens frame or the annular collecting ring mentioned later by welding or screws. The elastic deformation section is the main area providing flexible support and absorbing lens assembly stress and thermal mismatch deformation. The support section is responsible for bonding to the outer support surface of the lens by adhesive. Its end is usually machined into a flat or slightly curved surface to conform to the curvature of the lens, increasing the contact area and evenly distributing the bonding pressure. To ensure the spring has both sufficient support rigidity and excellent flexibility, a gradual transition zone is set between the root fixing section and the elastic deformation section. Figure 2 As can be seen, the cross-sectional width of the transition zone decreases linearly from the end of the root fixed section towards the elastic deformation section along the length of the spring sheet, for example, the width smoothly transitions from 3 mm to 1.5 mm. This design eliminates the abrupt right-angle cross-section change at the connection between the two, and can disperse the peak stress to a longer transition area when under stress, thereby avoiding microcracks caused by stress concentration.

[0028] The middle region of the elastic deformation section is provided with stress relief holes, which are elliptical in shape and whose major axis is set along the length of the spring sheet; the thickness of the elastic deformation section varies in gradient along the length direction, and the thickness at the root is greater than that at the end.

[0029] In the design of the elastic deformation section, an elliptical stress relief hole is incorporated in its central region. In engineering practice, this hole is typically formed using wire electrical discharge machining (EDM) or precision stamping, and a smooth surface finish must be ensured to eliminate microscopic burrs at the hole edges. The major axis of the elliptical hole is intentionally positioned along the length of the spring piece, and both the major and minor axes must be less than the width of the spring piece at that location. Compared to common circular openings, the elliptical hole guides stress around the hole under stress, creating a stress redistribution area around the hole. This redirects tensile stress, originally concentrated at the free edge of the spring piece, to a uniform force field around the hole, significantly reducing the maximum local peak stress. Figure 4 The simulation curves in the left and right figures visually reflect this effect: in the absence of holes, the stress spike is concentrated at the edges; however, after adding elliptical holes, the stress peak significantly decreases and the stress distribution becomes more gradual. Furthermore, to balance the stiffness of the spring and the constraint force of the lens, the thickness of the elastic deformation section varies gradient along its length, being thicker at the root and thinner at the ends. For example, Figure 2 In the illustrated embodiment, the root thickness is set to 1.0 mm, the end thickness is as thin as 0.6 mm, and a linear decreasing transition is used in the middle. This thickness gradient design allows the bending stiffness of the spring to gradually change along the length direction. Therefore, even if thermal mismatch stress is generated inside the spring when the temperature changes, the stress will not suddenly increase at a certain cross section due to the orderly gradual change in stiffness. At the same time, the thinner end design reduces the radial constraint on the lens, effectively preventing distortion of the lens's optical surface.

[0030] The spring sheet includes an elastic metal base layer and a first heat-conducting layer and a second heat-conducting layer respectively bonded to the upper and lower surfaces of the elastic metal base layer. The elastic metal base layer is made of stainless steel, and the first and second heat-conducting layers are made of copper or copper alloy.

[0031] To address the heat dissipation issue, the contact spring itself is not a single metal foil, but rather employs a multi-layered composite structure. For example... Figure 3As shown in the cross-sectional diagram of the spring, the spring consists of a central elastic metal base layer, and a first thermally conductive layer and a second thermally conductive layer respectively bonded to the upper and lower surfaces of the elastic metal base layer. In terms of material selection, the elastic metal base layer is made of 430F stainless steel, which possesses excellent yield strength and fatigue resistance, providing the necessary mechanical support for the spring. The first and second thermally conductive layers are made of T2 copper or copper alloy. The thickness ratio of the three layers directly affects the overall performance of the spring. As a preferred specific value, the thickness of the elastic stainless steel base layer can be set to 0.5 mm, and the thickness of the upper and lower copper layers is 0.15 mm each. In terms of manufacturing process, these three layers are bonded together under vacuum and high temperature conditions using a diffusion welding process. The diffusion welding temperature is typically controlled between 850℃ and 900℃, with a holding time of approximately 2 hours, to ensure that the copper layer and the stainless steel base layer form an atomic-level metallurgical bond at the interface, fundamentally preventing the risk of peeling of the composite layer during repeated bending of the spring.

[0032] A thermally conductive adhesive layer is provided between the support section and the lens support surface to reduce contact thermal resistance and guide heat into the spring.

[0033] At the assembly level, the support section and the lens support surface are not in direct contact; instead, a thermally conductive adhesive layer is used. This adhesive layer uses an epoxy resin-based adhesive as the main component, with highly thermally conductive inorganic fillers (such as approximately 30%–50% by mass of micron-sized boron nitride or aluminum oxide powder) evenly dispersed within it. During construction, the filler-containing thermally conductive adhesive is evenly applied to the surface of the support section, then the lens is pressed into place and cured. The thickness of the cured adhesive layer is controlled between 0.05 mm and 0.2 mm, ensuring sufficient bonding strength while significantly reducing thermal resistance caused by microscopic gaps at the contact surface. Figure 5 As shown, the heat generated by the lens during operation enters the spring through this point and is quickly conducted away using the high thermal conductivity of the copper layer.

[0034] An annular heat-conducting collection ring is fixedly installed on the inner side of the annular frame. The annular heat-conducting collection ring is heat-conductingly connected to the root fixed section of each spring piece, and is used to collect the heat conducted by each spring piece and transfer it outward to the annular frame.

[0035] To collect the heat conducted by the spring clips, a ring-shaped heat-conducting collection ring is specifically fixed to the inner side of the annular frame. This collection ring is also made of copper or copper alloy, and one side has a groove or mounting boss that matches the shape of the spring clip's root fixing section. During actual assembly, the root fixing sections of each spring clip are first positioned and fixed to the annular heat-conducting collection ring by brazing or laser welding. During welding, silver-based or copper-based solder is filled between the contact surfaces. After the solder melts, it completely wets and fills the microscopic gaps in the contact surfaces, achieving a low thermal resistance metallurgical connection between the components. Then, the annular collection ring containing the spring clip assembly is embedded into the inner wall of the annular frame and fixed in place. (Refer to...) Figure 5 The arrows illustrating the heat flow direction show that heat conducted from the lens to the spring support section passes rapidly through the copper layers on both sides of the spring, through the elastic deformation section, and is collected at the root by the collection ring. Finally, it is conducted to the annular frame with a large heat capacity for natural heat dissipation, forming a complete, low-thermal-resistance directional heat conduction path. The entire assembly process achieves efficient heat dissipation without the need for additional heat sinks or heat pipes.

[0036] Furthermore, the cross-sectional width of the gradual transition zone decreases linearly from the root fixed section to the elastic deformation section, forming a decreasing region, and the length of the decreasing region is less than the length of the elastic deformation section.

[0037] When implementing this multi-spring support configuration, the specific geometric dimensions and location design of the gradual transition zone must adhere to specific constraints. As described in the above embodiment, the connection between the root fixed section and the elastic deformation section is not a simple right-angle turn, but rather a transition through a gradually narrowing cross-sectional area. In actual machining, the contour of this transition zone is typically formed using precision wire cutting or CNC milling, with straight beveled edges on both sides, so that the cross-sectional width decreases uniformly and linearly from the end of the root fixed section along the spring length towards the beginning of the elastic deformation section.

[0038] by Figure 2 Taking the specific spring configuration shown as an example, a set of specific dimensional parameters can be set to enable those skilled in the art to reproduce it: assuming the width of the root fixing section is 3.0 mm, after entering the gradual transition zone, its width shrinks at a fixed slope until the starting position of the elastic deformation section, where the width drops to 1.2 mm. The extension length of this gradual transition zone along the length direction of the spring is deliberately designed to be less than the overall length of the subsequent elastic deformation section.

[0039] For example, the length of the gradient transition zone (i.e., the width-decreasing region) can be set to 6.0 mm, while the length of the subsequent elastic deformation section is 18.0 mm, with a length ratio of approximately 1:3. This design clarifies the physical location of the gradient zone—it occupies only a limited length from the root of the spring to the middle front section, while the majority of the remaining area of ​​the elastic deformation section maintains a constant width or is only affected by the elliptical hole and thickness gradient.

[0040] This method of achieving "linear decrease with a decrease length less than the length of the elastic segment" plays a crucial role in structural function. The constraint that the decrease length is less than the total length of the elastic deformation segment ensures that the flexible deformation capability of the spring sheet is mainly concentrated in the narrow region of the middle of the elastic deformation segment, rather than experiencing a sudden drop in stiffness at the root. If the length of the transition zone is too long, even exceeding the elastic deformation segment, the stiffness reduction of the spring sheet will occur throughout its entire length, resulting in insufficient connection strength at the root. Conversely, if this constraint meets the design requirements, the transition zone only serves as a "buffer zone for stiffness-flexibility transition," retaining sufficient bending cross-section at the root to resist torque and external impacts during assembly, while ensuring that the subsequent elastic segment still has enough space for flexural deformation.

[0041] At the manufacturing process level, in order to strictly ensure the accuracy of the linear decreasing dimension, it is usually necessary to reserve the corresponding gradual deformation cavity in the stamping die, or to set the precise straight line tilt angle in the EDM wire cutting program; after processing, it is also necessary to use an optical projector or a three-dimensional measuring instrument to check the uniformity of the decreasing width of the inclined edge to prevent the stress dispersion symmetry from being destroyed due to local size being too thick or too thin.

[0042] In this embodiment, the linearly decreasing hypotenuse shape is geometrically simple and regular, making it easier to perform high-precision batch processing on conventional CNC equipment compared to a curved decreasing shape. It eliminates the need for complex toolpath programming, reducing manufacturing costs. By strictly limiting the decreasing region to a short distance at the root, it creates a spatial distance from the subsequent elliptical stress relief holes, preventing excessive weakening of local structural strength due to overlap between the openings and the width-decreasing region. This layout significantly alleviates stress concentration at the root of the spring sheet when subjected to radial loads, as it enters the gradual transition zone. Simultaneously, the middle section of the elastic deformation segment retains sufficient constant width material, providing continuous flexible compensation during significant thermal expansion and contraction. This greatly enhances the fatigue life of the spring sheet support structure and extends the maintenance cycle of the precision optical system. Figure 2 The main view clearly shows the relative length relationship between the linear gradient segment and the subsequent elastic deformation segment, in conjunction with... Figure 4 The simulated stress distribution curve in the left figure confirms the effect of reducing root stress under this length constraint condition.

[0043] Furthermore, the lengths of both the major and minor axes of the elliptical stress relief hole are less than the width of the elastic deformation segment at the corresponding position, and the length of the major axis is greater than the length of the minor axis.

[0044] When creating a stress relief hole in the middle region of the elastic deformation section of a spring, the determination of its geometric parameters must consider both stress dissipation effect and structural integrity. In actual design, the hole is preferably located in the middle section of the elastic deformation section, avoiding the root gradient zone where stress concentration occurs and not close to the end support section, to ensure that there is sufficient material around the hole for stress redistribution.

[0045] For the contour of the stress relief hole, the dimensional constraints of its major and minor axes must be strictly defined before machining. Specifically, the major axis of the elliptical hole must be set along the length of the spring (i.e., parallel to the main bending direction of the spring), and its length must be greater than its length to form a narrow ellipse that conforms to the stress characteristics. For example, in practical engineering, if the effective width (i.e., the local lateral dimension without thickness gradient changes) at the corresponding position in the middle of the elastic deformation section is set to 3.0 mm, then the major axis of the elliptical hole can be set to 1.8 to 2.2 mm, and the minor axis can be set to 0.6 to 1.0 mm. The selection of these two dimensions must satisfy the condition that their absolute values ​​are both less than the total width of the elastic deformation section at that location, thereby retaining sufficient thickness of solid material at the hole edge to avoid transverse truncation of the spring due to excessively large holes, or tearing of the hole edge material during long-term fatigue bending.

[0046] From a mechanical perspective, the shape of an elliptical hole is one of the optimal geometric forms for dealing with stress concentration in thin-walled metal structures. For example... Figure 4 As shown by the curve on the right, when the spring is subjected to tensile or bending loads, the presence of this elliptical hole can guide the peak stress originally concentrated at the free edge of the spring to a uniform stress field around the hole; since the major axis is parallel to the principal direction of force, the curvature change at the edge of the hole is more gradual, according to the stress concentration factor formula... It is estimated that this elliptical profile, compared to a circular opening of the same area, can effectively reduce the maximum local peak stress at the edge of the opening. The value of the value is reduced to decrease the stress concentration factor.

[0047] pass Figure 4 A comparison of the stress distribution trends in the two figures clearly shows that after creating the elliptical hole, the original steep stress peaks of the spring are significantly smoothed out, and the stress around the hole tends to be more uniform. Simultaneously, strictly controlling the dimensions of the major and minor axes within the local width of the spring effectively prevents the hole edge from being too close to the side of the spring, avoiding the formation of thin-walled edges with sharp burrs. This design ensures that after repeated temperature cycles or mechanical vibrations, fatigue microcracks are less likely to form at the edge of the stress relief hole, thus maintaining the long-term elastic properties of the spring and the geometric accuracy of the lens support surface. Figure 2 The main view of the spring clearly shows the outline and relative position of the elliptical hole in the middle of the elastic deformation section, and... Figure 4 The simulation curves provide a complete verification.

[0048] Furthermore, the thickness of the elastic deformation section decreases linearly or curvilinearly from one end near the root fixing section to one end near the support section, so that the end of the spring sheet near the lens support surface has the lowest radial constraint stiffness.

[0049] In designing the thickness of the elastic deformation section of the spring, a continuously thinning scheme is adopted along its length. Specifically, the thickness of the elastic deformation section decreases uniformly from one end near the root fixing section towards the end near the support section. (Refer to...) Figure 2 In the specific embodiment shown, the thickness of the root fixing section itself is designed to be 1.0 mm to ensure sufficient connection strength and bending section modulus at the junction of the root and the frame; the initial thickness of the elastic deformation section is the same as that of the root, and then it is continuously thinned along the extension direction (for example, within a length range of about 15 to 20 mm) until the edge near the support section, where its thickness is reduced to about 0.6 mm.

[0050] To ensure the radial constraint stiffness at the tip of the spring is indeed minimized, the final thickness at the tip is controlled to be below 0.6 mm during implementation. In actual assembly, when the tip of the spring is subjected to a small thrust generated by the thermal expansion and contraction of the lens, the reaction force against deformation provided at that local location is significantly less than that at the root due to the extremely thin end section. In materials mechanics, the bending moment of inertia at the tip is proportional to the cube of the thickness; therefore, the stiffness reduction effect of thickness reduction is far greater than that of width adjustment. This thinning process, from... Figure 2 The thickness markings clearly show the wall thickness variation between "1.0 mm at the root" and "0.6 mm at the end". The design of the support section is to support this 0.6 mm thickness, with a thermally conductive adhesive layer coated on its upper surface and the lens bonded thereon.

[0051] This thickness-decreasing design creates a stiffness gradient along the length of the spring, characterized by high stiffness at the root and low stiffness at the ends. The practical effect of this layout is that the end of the spring near the lens edge has the lowest radial constraint stiffness. When the environment of the optical system experiences temperature changes (e.g., the temperature rises from 20°C to 40°C after the chip inspection equipment is powered on), the end of the spring, due to its minimal resistance, can flexibly conform to the slight radial thermal expansion displacement of the lens, avoiding thermal mismatch stress caused by the mismatch in the material's coefficient of thermal expansion (according to...). The stress is directly and rigidly transferred to the lens. This is crucial for protecting the lens from localized stress compression and maintaining the optical shape (PV) value from deterioration. Figure 2 Thickness steps and Figure 5 The heat conduction paths can work together: although the ends are thin and have low stiffness, their surfaces are still covered with a copper heat-conducting layer, ensuring that the heat conduction efficiency is not affected by the thinning design, thus achieving the coexistence of mechanical load reduction and heat dissipation capacity.

[0052] Furthermore, the thermally conductive adhesive layer is a composite colloid in which a highly thermally conductive filler is dispersed in an epoxy resin-based adhesive, and the highly thermally conductive filler is selected from one or more combinations of boron nitride, alumina, carbon nanotubes or graphene.

[0053] Boron nitride and aluminum oxide: These are insulating and thermally conductive fillers with relatively moderate cost, ensuring that no parasitic capacitance or electrochemical corrosion occurs along the lens support path.

[0054] Carbon nanotubes and graphene: with extremely high thermal conductivity, they are often used for high-end heat dissipation. Their fibrous or sheet-like structures can overlap within the adhesive layer to form more efficient three-dimensional thermal conduction pathways (thermal bridges).

[0055] During assembly, this thermally conductive adhesive is applied. After curing, it not only firmly adheres the lens to the spring support section but also completely fills the air gap between the lens and the spring. Since air has extremely poor thermal conductivity, the contact thermal resistance would be very high if it were not filled. After filling with this highly thermally conductive adhesive, the thermal resistance is significantly reduced, ensuring that the heat generated by the lens can smoothly and unimpededly "cross" this adhesive layer and successfully enter the copper thermally conductive layer of the spring.

[0056] Furthermore, the decreasing length of the cross-sectional width of the gradual transition zone and the thickness gradient of the elastic deformation segment are determined through the following steps:

[0057] Based on the stress concentration factor formula The length of the decreasing cross-sectional width of the gradual transition zone is determined such that the theoretical stress concentration factor corresponding to the maximum abrupt change in cross-sectional slope within the decreasing cross-sectional width range of the gradual transition zone is less than a preset threshold. The stress concentration factor is... For the maximum local stress, This represents the theoretical average stress.

[0058] In actual design, the initial geometric model of the spring is first established in CAD software. Assume the width of the fixed root section is W1, the width at the starting point of the elastic deformation section is W2, and the decreasing length is L. This step uses the stress concentration factor formula. As an evaluation criterion, among which The stress concentration factor is... The maximum local stress is extracted based on linear elastic finite element simulation (or theoretical photoelastic experiment). This represents the theoretical average stress calculated assuming a uniform cross-section.

[0059] In engineering iterations, a safety threshold for the stress concentration factor is typically pre-set, for example, by setting a safety threshold for the stress concentration factor. The length is limited to between 1.5 and 2.0. Designers input the initial decreasing length L into the simulation model and apply loads to extract... And perform the calculation. If the calculated If the gradient length is greater than the preset threshold, it indicates that the decreasing length is too short and the abrupt change in the slope of the cross-section is too large. In this case, the length L of the gradient zone needs to be appropriately increased until the theoretical value corresponding to the slope is reached. The value converges to below a preset threshold. For example, if, after multiple rounds of simulation, the length L is gradually increased from the initial 4 mm to 6 mm, The value was reduced from 2.3 to 1.7, which met the design requirements. Therefore, the 6 mm value is the final determined length of the gradient transition zone.

[0060] Based on the thermal mismatch stress formula The thickness gradient change of the elastic deformation section is determined so that the maximum thermal mismatch stress generated within the expected operating temperature range does not exceed the material yield strength of the elastic metal base layer, thereby achieving the synergistic operation of the two stress reduction structures. For thermal mismatch stress, For elastic modulus, The coefficient of linear expansion is 1 / 3. This represents the change in temperature.

[0061] When addressing thermal compatibility issues, the physical properties of the material must be considered. In practice, the thermal mismatch stress formula can be applied. To make an estimate, among which For thermal mismatch stress, For elastic modulus, The coefficient of linear expansion is 1 / 3. This represents the expected temperature change. Taking the selected 430F stainless steel elastic metal base layer as an example, the elastic modulus of this material is... Approximately 200 GPa, coefficient of linear expansion Approximately 10.5 × 10 -6 / ℃, if the expected temperature rise of the optical system's operating environment If the temperature is 20℃, the theoretical maximum thermal mismatch stress is about 42MPa, which is much lower than the yield strength of about 350MPa for 430F stainless steel.

[0062] To ensure good resilience under dynamic temperature changes, this step disperses local stress by applying different thickness gradients to the spring sheet. Specifically, during 3D modeling, an initial linear decreasing slope is set from 1.0 mm at the root to 0.6 mm at the tip, and this model is then used in a finite element thermo-structural coupling analysis. In the simulation, a temperature difference load exceeding the actual extreme operating environment (e.g., 40℃ or 50℃) is applied, and the actual maximum thermal stress at each cross-section of the spring sheet is extracted to verify whether it remains below the material's yield strength. If the simulation results indicate excessive end deformation or local stress exceeding the yield strength, the gradient slope needs to be appropriately reduced (e.g., increasing the end thickness from 0.6 to 0.7), or a curve-decreasing gradient needs to be adopted until both static and fatigue mechanical standards are met. The final determined thickness gradient change often needs to be checked in conjunction with the decreasing length from step one to ensure that the spring sheet, after combining the two, maintains its elastic working state under extreme conditions.

[0063] Introducing the above two formulas as the design basis provides clear theoretical support for the structural parameters of the spring. Step one can precisely control the geometric discontinuities at abrupt changes in the cross-section, significantly reducing the stress concentration factor at the root of the spring. Step two, by predicting the thermal stress in the temperature field, allows the stiffness of the spring to progressively match the thermal displacement requirements along its length. The combination of these two methods avoids the problems of insufficient local strength or excessive constraint that may result from traditional empirical methods, ensuring that the spring remains within a safe elastic operating range throughout its service life. Figure 2 The gradient region and thickness dimension markings in the text can be used as the final output result for parameter determination, while Figure 4 The stress comparison curve can visually verify the results in step one. The actual effect of the value decrease.

[0064] Furthermore, the thicknesses of the first thermally conductive layer and the second thermally conductive layer are determined through the following steps:

[0065] Formula based on the equivalent thermal conductivity of multilayer composite structures Based on the thickness of the elastic metal base layer, the initial thickness ratio of the first thermally conductive layer and the second thermally conductive layer is set to make the overall equivalent thermal conductivity of the spring sheet... The improvement rate compared to a single stainless steel base layer reaches the preset percentage; The equivalent thermal conductivity is The independent thermal conductivity of each layer of material, This represents the cross-sectional area through which heat flows through each layer of material.

[0066] In this embodiment, the thickness reference of the elastic metal base layer (430F stainless steel) is first determined. (See attached...) Figure 3In practical implementation, the composite layer structure shown typically uses a stainless steel base layer with a thickness of 0.5 mm as the rigid support. Then, T2 copper is selected as the material for both the first and second thermally conductive layers. The thermal conductivity of stainless steel is known. The thermal conductivity of copper is approximately 16 W / (m·K). Approximately 401 W / (m·K). Based on the formula for the equivalent thermal conductivity of multilayer composite structures... (in The equivalent thermal conductivity is The independent thermal conductivity of each layer of material, (where is the vertical cross-sectional area of ​​the heat flow through each material layer). In the initial model, the initial thickness of both the upper and lower copper layers is set at 0.1 mm. At this point, stainless steel occupies a large proportion of the overall cross-sectional area, and the calculated equivalent thermal conductivity is only about 4 to 5 times that of pure stainless steel. To achieve good thermal conductivity, a target can be set in advance, such as the equivalent thermal conductivity of the spring needing to be more than 10 times that of stainless steel. Therefore, in the iteration, the copper layers are gradually thickened, increasing the thickness of the upper and lower copper layers to 0.15 mm. At this point, the total cross-sectional area occupied by the copper layers increases significantly. Substituting into the formula, the equivalent thermal conductivity can be increased to 12 to 15 times the original, meeting the preset thermal conductivity improvement target. This 0.15 mm thickness of the upper and lower copper layers is the initial value for the next step of verification.

[0067] Based on Fourier's law of heat conduction Based on the preset heat source power of the lens and the heat dissipation conditions from the annular heat collection ring to the annular lens frame, the final thickness of the first heat-conducting layer and the second heat-conducting layer is iteratively corrected and determined so that the temperature rise at the center of the lens is lower than the allowable threshold under steady-state working conditions. For heat dissipation, Thermal conductivity, For heat transfer area, For temperature difference, This represents the length of the heat conduction path.

[0068] After obtaining the initial thickness ratio, a fine-tuning process is required based on actual heat dissipation needs. The spring and frame structure is simplified into a steady-state heat conduction model, following Fourier's law of heat conduction. (In the formula, The power of the heat source generated by the lens. The thermal conductivity of the material The heat transfer cross-sectional area is perpendicular to the heat flow direction. The desired temperature difference is between the lens and the frame. (This is the path length from the lens support section to the annular collection ring, where heat is conducted.)

[0069] In engineering design, the heat source power of the lens during operation is assumed to be... This is a fixed value (e.g., approximately 2.0 watts of heat generated when the lens absorbs laser or illumination light). See attached reference. Figure 5 The direction of heat conduction, the length of the heat path The heat transfer cross-sectional area is approximately equal to the length of the elastic deformation section plus the root fixing section (e.g., 12 mm). It is approximately equal to the width of the spring multiplied by the total thickness of the composite layer (for example, if the spring width is 3.0 mm and the total thickness of the composite layer is 0.8 mm, then the cross-sectional area of ​​a single spring is approximately 2.4 square millimeters).

[0070] Substitute the initial thickness values ​​set in step one (0.15 mm × 2 for copper layer, 0.5 mm for stainless steel) into the specific parameters. First, calculate the equivalent thermal conductivity of the spring sheet. Approximately 180 W / (m·K) (the actual value depends on the precise cross-sectional area ratio). Using a modified Fourier formula... To verify the temperature difference, substitute the values: The calculated temperature was approximately 55°C, indicating that the lens temperature rise might be excessive (the allowable temperature rise range for precision optical systems is typically between 15°C and 30°C). In this case, the designer must return to step one to correct the initial thickness, increasing the thickness of the upper and lower copper layers (e.g., increasing each layer from 0.15 mm to 0.25 mm). After rechecking, due to the significant increase in the equivalent cross-sectional area of ​​the copper layers, the equivalent thermal conductivity is significantly improved, resulting in a lower calculated steady-state temperature rise. The temperature will drop below 15℃. After multiple iterations of "correcting the thickness → recalculating the equivalent thermal conductivity → verifying the temperature rise", the thickness of the upper and lower heat-conducting layers was finally determined. In actual products, the thickness of the upper and lower copper layers is fixed at 0.2 mm or 0.25 mm, which can ensure the heat dissipation requirements and protect the copper layer from excessive fatigue when the spring is bent.

[0071] Through the derivation and verification of the above two steps, the final determined copper layer thickness parameters have sufficient theoretical basis. It avoids relying on experience to determine the thickness, ensuring that the designed composite layer can accurately match the actual heat generation power and heat dissipation path length of the optical system while meeting the target thermal conductivity improvement rate. This strictly controls the steady-state temperature rise of the lens within the design allowable threshold, suppressing thermal deformation of the lens caused by excessive temperature rise. Figure 3 The cross-sectional diagram of the composite layer visually demonstrates the thickness ratio of each layer. Figure 5 The heat flow path diagram illustrates the practical application of Fourier's law in directional heat conduction.

[0072] Furthermore, the annular heat-conducting collection ring is made of copper or copper alloy. The annular heat-conducting collection ring and the root fixing section of each spring are connected by brazing or laser welding to form a heat-conducting connection. The contact surface between the annular heat-conducting collection ring and the root fixing section of the spring is filled with heat-conducting brazing filler metal.

[0073] Even if the metal surfaces at the base of the spring and the metal surfaces of the collecting ring appear perfectly flat, countless tiny air gaps will still exist when they are directly bonded together on a microscopic scale (air is a poor conductor of heat). During the brazing process, the molten, thermally conductive brazing filler metal actively penetrates and fills these microscopic gaps, transforming the original "point contact" into a complete "surface metallurgical bond," thus completely eliminating the contact thermal resistance at this stage.

[0074] Furthermore, the thickness of the elastic metal base layer is 0.4mm~0.8mm, and the thickness of the first heat-conducting layer and the second heat-conducting layer is 0.1mm~0.3mm; and the single-layer thickness of the elastic metal base layer is greater than the single-layer thickness of the heat-conducting layer on either side.

[0075] 0.4~0.8mm stainless steel base layer: This thickness provides sufficient bending section modulus so that the spring can bear the weight of the lens and ensure a certain rigidity; at the same time, it is not too thick to cause excessive rigidity (so that the assembly stress cannot be flexibly reduced).

[0076] A copper layer of 0.1~0.3mm: This thickness is sufficient to form a continuous transverse heat conduction channel on the cross-section of the spring sheet, which greatly improves the equivalent thermal conductivity of the composite spring sheet; at the same time, it does not significantly increase the overall bending stiffness of the spring sheet, and avoids weakening the flexibility of the spring sheet due to excessive copper layer thickness.

[0077] The mandatory relationship that the thickness of the base layer is greater than the thickness of the heat-conducting layer on one side is a crucial design feature. Specifically, the core function of the spring sheet is "elastic support," not "pure heat conductor." Therefore, the stainless steel base layer must be the skeleton of the composite structure and the absolute load-bearing body.

[0078] If the copper layer thickness is greater than or equal to the stainless steel base layer thickness in engineering, the deformation of the spring sheet under bending stress will be dominated by the soft and easily yielding copper, causing the spring sheet to lose its elastic recovery force and even resulting in delamination between the copper layer and the stainless steel substrate. Mandating that "the thickness of a single layer of stainless steel base layer > the thickness of the copper layer on either side" is to ensure that the neutral layer and the main load-bearing layer of the spring sheet remain within the stainless steel layer when bent, allowing the copper layer to merely act as a "heat dissipation skin" attached to the surface of the stainless steel frame, achieving an excellent functional zoning where mechanical strength relies on steel and thermal conductivity on copper.

[0079] In an exemplary embodiment, during the assembly and testing of the above-mentioned support configuration, to address the potential microscopic surface distortions (such as irregular astigmatism detected by an optical interferometer) that may occur after the lens has cured with adhesive, this embodiment provides a method for in-situ compensation without disassembling the lens, comprising the following steps:

[0080] Step 1: For the multi-spring support configuration in the above embodiments, the current surface distortion data of the lens is obtained using an optical interferometer. Specifically, after the lens assembly and curing are completed, the actual surface shape of the lens is measured using an interferometer, and the PV value (peak-valley value) error distribution is extracted. Based on the structural finite element model, the required micro-displacement compensation amount (usually in the micrometer or even nanometer range) of each support segment in the spatial Z-axis or X-axis direction is calculated in reverse, thereby determining the required micro-displacement compensation amount of each spring support segment in the spatial coordinate system. For example, if a micro-dimple is detected at a certain point on the lens due to the shrinkage of the adhesive layer, the spring support segment at that location needs to generate a small outward displacement of 0.5 μm towards one side of the lens.

[0081] Step 2: Based on the micro-displacement compensation amount, select the corresponding spring piece that needs to be adjusted for displacement, and precisely align the micro adjustable power heat source with the local area of ​​the elastic deformation section of the selected spring piece near the root fixed section.

[0082] Because the composite layer of the spring clip (stainless steel base and copper layers on both sides) expands when heated, the copper (with a coefficient of linear expansion of approximately 17 × 10⁻⁶)... -6 The thermal expansion of stainless steel (approximately 10.5 × 10⁻⁶ °C) is significantly greater than that of stainless steel (approximately 10.5 × 10⁻⁶ °C). -6 / ℃), this composite layer structure naturally possesses actuation characteristics similar to a "bimetallic sheet". Accordingly, the operator selects the specific spring that needs to be deformed and uses a micro-power adjustable heat source (such as an infrared laser point heating device or a temporary contact micro ceramic heating plate) as an external excitation source.

[0083] Step 3: Turn on the micro adjustable power heat source to heat the local area in a controlled manner. Utilize the material property that the linear expansion coefficient of the copper thermal conductive layer in the spring sheet is greater than that of the stainless steel elastic metal base layer, so that the composite layer of the spring sheet will produce bimetallic thermal bending deformation at the heating section, thereby causing the support section of the spring sheet to produce a displacement equal to the micro displacement compensation amount.

[0084] The heat source is precisely targeted at a specific area of ​​the elastic deformation section of the selected spring (e.g., near the junction of the root fixed section and the gradual transition zone), and controlled heating power and heating time are applied. At the moment of heating, because the copper layer expands more due to heat while the stainless steel layer remains relatively stable, the bending section of the spring will undergo a slight, reverse torsional or bending deformation due to the thermal expansion mismatch in the material cross-section, thereby causing the support section to produce the expected slight displacement.

[0085] Step 4: During the heating compensation process, continuously monitor the real-time changes in the surface shape of the lens. When the lens surface shape distortion data converges to the preset qualified threshold, turn off the micro adjustable power heat source. After the spring sheet cools to room temperature, remove the heat source and use the shape locking after the internal stress redistribution during the heating process of the spring sheet to complete the in-situ compensation of the lens surface shape.

[0086] Before heating, continuously monitor the wavefront phase data of the interferometer. When the displacement compensation at the support end reaches the ideal value calculated in step one, immediately stop heating and allow the spring to cool to room temperature. Because the stress accumulated inside the spring during heating is released and redistributed, the spring will maintain its new geometric shape after cooling. Re-measure the lens surface shape; if the PV value has converged significantly, the compensation is complete.

[0087] In this embodiment, by giving the spring a "active actuation" function, in-situ non-destructive compensation of the lens surface shape is achieved. Compared with traditional methods that require disassembling the lens for re-grinding or adding a fine-tuning mechanism, this solution does not require any additional driving components or moving parts. It fully utilizes the inherent material property of the different coefficients of linear expansion between stainless steel and copper in the composite layer of the spring itself. By generating minute thermal bending deformation through controlled local heating, micron or even nanometer-level support point displacement compensation can be achieved. Combined with real-time online detection by an interferometer, this method can make precise directional adjustments based on the actual surface shape deviation of the lens, significantly reducing the rework rate caused by adhesive layer curing shrinkage or residual assembly stress in precision optical assembly, and effectively improving the final pass rate of the lens optical surface shape and the long-term imaging quality stability of the system.

[0088] Embodiments of the present invention also provide an optical system, including an optical lens and a multi-spring support configuration with stress dispersion and directional heat conduction functions as described in the above embodiments. The side support surface of the optical lens is bonded and fixed to the support section of the spring through the thermally conductive adhesive layer, and the thermally conductive adhesive layer completely covers the mating gap between the support section and the lens support surface.

[0089] While specific embodiments of the invention have been described in detail by way of examples, those skilled in the art should understand that the examples are for illustrative purposes only and are not intended to limit the scope of the invention. Those skilled in the art should also understand that various modifications can be made to the embodiments without departing from the scope and spirit of the invention.

Claims

1. A multi-sheet support configuration with stress dispersion and directional heat conduction functions, characterized in that, include: A ring-shaped lens frame, and a number of spring pieces spaced circumferentially on the inner side of the ring-shaped lens frame; each spring piece includes an integrally connected root fixing section, an elastic deformation section and a support section; the root fixing section is fixedly connected to the ring-shaped lens frame, the support section is used to bond to the lens support surface, and the elastic deformation section is connected between the root fixing section and the support section. A gradual transition zone is provided between the root fixing section and the elastic deformation section, and the cross-sectional width of the gradual transition zone decreases from the root fixing section to the elastic deformation section along the length direction of the spring sheet. The middle region of the elastic deformation section is provided with a stress relief hole, which is elliptical and the major axis of the stress relief hole is set along the length of the elastic piece; the thickness of the elastic deformation section varies in gradient along the length direction, and the thickness at the root is greater than the thickness at the end. The spring includes an elastic metal base layer and a first heat-conducting layer and a second heat-conducting layer respectively bonded to the upper and lower surfaces of the elastic metal base layer. The elastic metal base layer is made of stainless steel, and the first and second heat-conducting layers are made of copper or copper alloy. A thermally conductive adhesive layer is provided between the support section and the lens support surface to reduce contact thermal resistance and guide heat into the spring sheet. An annular heat-conducting collection ring is fixedly installed on the inner side of the annular frame. The annular heat-conducting collection ring is heat-conductingly connected to the root fixed section of each spring piece, and is used to collect the heat conducted by each spring piece and transfer it outward to the annular frame.

2. The multi-sheet support configuration with stress dispersion and directional heat conduction functions according to claim 1, characterized in that, The cross-sectional width of the gradual transition zone decreases linearly from the root fixed section to the elastic deformation section, forming a decreasing region, and the length of the decreasing region is less than the length of the elastic deformation section.

3. The multi-sheet support configuration with stress dispersion and directional heat conduction functions according to claim 1, characterized in that, The lengths of both the major and minor axes of the elliptical stress relief hole are less than the width of the elastic deformation segment at the corresponding position, and the length of the major axis is greater than the length of the minor axis.

4. The multi-sheet support configuration with stress dispersion and directional heat conduction functions according to claim 1, characterized in that, The thickness of the elastic deformation section decreases linearly or curvilinearly from the end near the root fixed section to the end near the support section, so that the end of the spring sheet near the lens support surface has the lowest radial constraint stiffness.

5. The multi-sheet support configuration with stress dispersion and directional heat conduction functions according to claim 1, characterized in that, The thermally conductive adhesive layer is a composite colloid in which a highly thermally conductive filler is dispersed in an epoxy resin-based adhesive. The highly thermally conductive filler is selected from one or more combinations of boron nitride, alumina, carbon nanotubes, or graphene.

6. The multi-sheet support configuration with stress dispersion and directional heat conduction functions according to claim 1, characterized in that, The decreasing length of the cross-sectional width of the gradual transition zone and the thickness gradient of the elastic deformation segment are determined through the following steps: Based on the stress concentration factor formula The length of the decreasing cross-sectional width of the gradual transition zone is determined such that the theoretical stress concentration factor corresponding to the maximum abrupt change in cross-sectional slope within the decreasing cross-sectional width range of the gradual transition zone is less than a preset threshold. The stress concentration factor is... For the maximum local stress, This is the theoretical average stress; Based on the thermal mismatch stress formula The thickness gradient change of the elastic deformation section is determined so that the maximum thermal mismatch stress generated within the expected operating temperature range does not exceed the material yield strength of the elastic metal base layer, thereby achieving the synergistic operation of the two stress reduction structures. For thermal mismatch stress, For elastic modulus, The coefficient of linear expansion is 1 / 3. This represents the change in temperature.

7. The multi-sheet support configuration with stress dispersion and directional heat conduction functions according to claim 1, characterized in that, The thicknesses of the first thermally conductive layer and the second thermally conductive layer are determined by the following steps: Formula based on the equivalent thermal conductivity of multilayer composite structures Based on the thickness of the elastic metal base layer, the initial thickness ratio of the first thermally conductive layer and the second thermally conductive layer is set to make the overall equivalent thermal conductivity of the spring sheet... The improvement rate compared to a single stainless steel base layer reaches the preset percentage; The equivalent thermal conductivity is The independent thermal conductivity of each layer of material, This is the cross-sectional area through which heat flows through each layer of material; Based on Fourier's law of heat conduction Based on the preset heat source power of the lens and the heat dissipation conditions from the annular heat collection ring to the annular lens frame, the final thickness of the first heat-conducting layer and the second heat-conducting layer is iteratively corrected and determined so that the temperature rise at the center of the lens is lower than the allowable threshold under steady-state working conditions. For heat dissipation, Thermal conductivity, For heat transfer area, For temperature difference, This represents the length of the heat conduction path.

8. The multi-sheet support configuration with stress dispersion and directional heat conduction functions according to claim 1, characterized in that, The annular heat-conducting collection ring is made of copper or copper alloy. The annular heat-conducting collection ring and the fixed section at the root of each spring are connected by brazing or laser welding to form a heat-conducting connection. The contact surface between the annular heat-conducting collection ring and the fixed section at the root of the spring is filled with heat-conducting brazing filler metal.

9. The multi-sheet support configuration with stress dispersion and directional heat conduction functions according to claim 1, characterized in that, The thickness of the elastic metal base layer is 0.4mm~0.8mm, and the thickness of the first heat-conducting layer and the second heat-conducting layer is 0.1mm~0.3mm; and the single-layer thickness of the elastic metal base layer is greater than the single-layer thickness of the heat-conducting layer on either side.

10. An optical system, characterized in that, The invention includes an optical lens and a multi-spring support configuration with stress dispersion and directional heat conduction functions as described in any one of claims 1 to 9, wherein the side support surface of the optical lens is bonded and fixed to the support section of the spring through the thermally conductive adhesive layer, and the thermally conductive adhesive layer completely covers the mating gap between the support section and the lens support surface.

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