Efficient processing method of large-size infrared aspheric silicon lens

Abstract

The application provides a high-efficiency processing method of large-size infrared aspheric silicon lens, according to the design requirements of drawings, a cylindrical lens blank with a processing allowance is cut; the outer cylindrical surface of the lens blank, the platform surface of the convex side and the concave side, the spherical convex surface and the aspheric concave surface are milled and ground; the outer circle and any platform surface of the lens are used as installation references, the aspheric concave surface and the spherical convex surface of the milled and ground aspheric lens are turned in sequence; a manipulator with integrated polishing tool head is used to coarsely polish and finely polish the surface of the turned silicon lens; ion beam polishing technology is used for fine polishing, and the processing of the infrared aspheric silicon lens is completed. The application provides a high-efficiency processing method of large-size aspheric silicon lens with digitization and quantization, and the technical speciality customization is carried out for the parts for infrared purposes such as infrared aspheric silicon lens, the boundaries of various process steps are defined, the process connection speed is accelerated, and the final forming precision is improved.

Description

Technical Field

[0001] This invention belongs to the field of advanced optical manufacturing and testing technology, and specifically relates to an efficient processing method for large-size infrared aspherical silicon lenses. Background Technology

[0002] Infrared optical components, represented by monocrystalline silicon, have numerous applications in semiconductors, optical remote sensing, and infrared night vision. However, due to the different application requirements in each field, monocrystalline silicon optical components vary significantly in size and manufacturing quality. For example, in the semiconductor field, monocrystalline silicon is often used as wafers with planar surface profiles and a maximum size of 300mm. In civilian applications such as infrared night vision, monocrystalline silicon is often designed as spherical surfaces with sizes ranging from 50 to 200mm and a processing accuracy requirement of approximately λ / 10RMS. In the field of space remote sensing, for the purpose of high-resolution military reconnaissance, monocrystalline silicon is used for high-order aspherical lenses in infrared channels, with a maximum size of Φ500mm and surface profiles that are mostly high-order aspherical, requiring a processing accuracy better than λ / 50RMS.

[0003] The industry's processing methods for monocrystalline silicon lenses mainly employ a combination of milling, turning, and classical polishing or CNC polishing. For small-sized aspherical silicon lenses with an aperture of 100mm or less, nanometer-level surface roughness can be achieved through single-point diamond turning, generally requiring no subsequent polishing or only a brief polishing to meet usage requirements. However, for larger-diameter silicon lenses, due to the hardness of monocrystalline silicon, a subsurface damage layer remains on the turned surface caused by tool wear and other factors. This damage layer typically has a depth of 20-40μm, requiring significant time for surface removal during subsequent aspherical silicon lens polishing, thus reducing manufacturing efficiency. In existing technologies, laser-assisted processing has been introduced to address the problem of turning monocrystalline silicon, but this process has poor engineering applicability, lacks flexibility, and produces unstable surface precision for the turned silicon lens, making it difficult to meet actual production requirements. Therefore, subsequent polishing becomes crucial. In polishing technology, classical polishing often employs single-axis polishing machines and other polishing equipment to polish the spherical surface of silicon lenses; aspherical polishing mainly uses CNC polishing technologies such as CCOS, airbags, and ion beams for aspherical surface shaping and finishing. However, these technology groups have not been specifically customized for infrared applications such as infrared aspherical silicon lenses, making it difficult to meet the high-quality processing requirements of large-size aspherical silicon lenses in the current space infrared field.

[0004] Therefore, it is necessary to provide an efficient processing method for large-size infrared aspherical silicon lenses to solve the problems in existing technologies, such as difficulty in meeting the processing accuracy requirements of large-size aspherical silicon lenses, easy deviation of key geometric parameters, and difficulty in meeting surface quality requirements. Summary of the Invention

[0005] To overcome the shortcomings of existing technologies, a highly efficient processing method for large-size infrared aspherical silicon lenses is provided. This method has advantages such as high processing accuracy and high efficiency, and also solves problems such as large edge errors and poor surface finish in traditional large-size infrared lens processing. At the same time, the proposed process has a high degree of full-chain CNC, which can eliminate the dependence on manual labor and better meet the needs of rapid batch production of large-size infrared lenses.

[0006] The technical solution provided by this invention is as follows:

[0007] A highly efficient fabrication method for large-size infrared aspherical silicon lenses includes the following steps:

[0008] According to the design requirements of the drawings, the monocrystalline silicon lens blank is cut into cylindrical lens blanks with machining allowance.

[0009] The outer cylindrical surface, convex side and concave side platform surface, spherical convex surface and aspherical concave surface of the mirror blank are milled using a milling machine;

[0010] Using a single-point diamond lathe, with the outer circle and either the convex or concave side of the lens as the mounting reference, the aspherical lens after milling is successively machined into aspherical concave surface and spherical convex surface; the high-frequency residual of the surface profile RMS after machining is better than 0.03λ under 15-20mm Gaussian high-pass filtering.

[0011] A robotic arm with an integrated polishing tool head performs rough polishing and surface profile smoothing on the surface of the turned silicon lens. After the surface profile is polished to a value better than λ / 20 and the RMS mid-to-high frequency residual is better than 0.02λ, the lens is then transferred to the robotic arm for fine polishing.

[0012] After precision polishing by the robotic arm, ion beam polishing technology is used to optimize the parameters of argon flow rate, radio frequency power, ion beam voltage, acceleration voltage, and ion source distance, and to optimize the removal function so that its frequency band removal capability matches the frequency band characteristics of the aspherical surface to be processed. After ion beam polishing, the processing of the infrared aspherical silicon lens is completed.

[0013] The efficient processing method for large-size infrared aspherical silicon lenses provided by the present invention has the following advantages:

[0014] (1) This invention provides a method for efficient processing of large-size aspherical silicon lenses using digitalization and quantification. It can eliminate the dependence on manual experience and has a high degree of automation. It has positive significance in shortening the development cycle of infrared aspherical lenses and improving processing accuracy.

[0015] (2) This invention establishes the Gaussian high-pass filter residual under the error characteristics of a specific frequency band as the main standard for whether the single-point diamond turning step is completed, which clarifies the boundaries of each process step, speeds up the process connection, and improves the final forming accuracy.

[0016] (3) Based on the high removal rate and high surface convergence efficiency of the robotic arm composite polishing, the turning quality requirements of monocrystalline silicon materials in the turning stage are reduced, and the process center is changed from the previous control of the single crystal silicon turning damage layer to rapid and effective removal. This allows large-size monocrystalline silicon aspherical lenses to be transferred to the subsequent polishing stage after one turning, reducing the number of repeated turning of the surface and reducing the difficulty of aspherical contour compensation.

[0017] (4) The robotic arm composite polishing method based on industrial robot carrier can complete the rapid removal of the surface damage layer of single crystal silicon, the rapid convergence of surface shape error and the control of surface smoothness on the same processing platform, which effectively improves the processing efficiency. Attached Figure Description

[0018] Figure 1 This is a schematic diagram of a high-efficiency processing flow for a large-size aspherical silicon lens according to the present invention.

[0019] Figure 2 This is an example of the fabrication of an aspherical silicon lens according to the present invention.

[0020] Figure 3 This is a typical surface error morphology distribution diagram during the fabrication process of the aspherical silicon lens of the present invention.

[0021] Figure 4 This is a distribution diagram of surface error morphology after high-pass filtering using a Gaussian function according to the present invention. Detailed Implementation

[0022] The features and advantages of the present invention will become clearer and more apparent from the following detailed description.

[0023] The term “exemplary” as used herein means “serving as an example, embodiment, or illustration.” Any embodiment illustrated herein as “exemplary” is not necessarily to be construed as superior to or better than other embodiments. Although various aspects of embodiments are shown in the accompanying drawings, the drawings are not necessarily drawn to scale unless specifically indicated otherwise.

[0024] This invention provides an efficient fabrication method for large-size infrared aspherical silicon lenses, such as... Figure 1 As shown, it includes the following steps:

[0025] Step 1: Blanking the mirror blank

[0026] According to the design requirements of the drawings, the monocrystalline silicon lens blank is cut into cylindrical blanks with a certain machining allowance by using rough processing equipment such as cutting machines.

[0027] Step 2: Mirror blank forming and surface milling

[0028] The mirror blank and surface are further shaped using a milling machine, mainly including milling the outer cylindrical surface, convex side and concave side platform surface, spherical convex surface and aspherical concave surface of the mirror blank.

[0029] Specifically, using the initial cylindricity of the outer circle and the bottom surface of the mirror blank as adjustment references, the upper surface of the mirror blank is milled, and the flatness error of the upper surface after milling is processed to within 10μm. Based on the completion of the upper surface machining, the concave and convex surfaces of the lens are milled sequentially on the bottom and upper surfaces. According to general design, concave surfaces are mostly aspherical, so aspherical milling of the concave surface is performed directly, and the surface accuracy after milling is controlled within 30μm PV.

[0030] The radial outer edges of the milled convex and concave sides have parallel plateau surfaces (e.g., ...). Figure 2 Using the concave B reference surface and its convex side opposite surface as a reference, a milling coordinate system is established to perform precision machining on the outer cylindrical surface of the lens.

[0031] During the milling process, the tolerances of various geometric parameters are controlled to meet the design requirements, with cylindricity error better than 10μm, flatness error of the convex and concave side platform surfaces better than 10μm, and parallelism error of the convex and concave side platform surfaces better than 10μm.

[0032] Step 3: Single-point diamond turning

[0033] The aspherical lens after milling is machined using a single-point diamond lathe. First, the flatness of the platform surface on either the convex or concave side is machined to within 2μm. Using the outer circle of the lens and either platform surface as the mounting reference, the concave aspherical surface is machined using a natural diamond circular arc tool. The tool parameters are generally: rake angle -25°, clearance angle 10–15°, arc radius 1–1.5mm, and waviness 100nm–250nm. The machining process parameters are adjusted according to the diameter of the part to be machined: spindle speed 1500–3500rpm, feed rate 2.5–10mm / min, depth of feed 3–10μm, and radial step distance 0.005–0.01mm. After completing the concave surface machining, the lens is flipped over for convex surface machining. During the flipping process, a uniform mounting reference is used to control the optical axis deviation of the lens.

[0034] After turning, the frequency band characteristics of the surface profile, under a 15-20mm Gaussian high-pass filter, show that the high-frequency residual in the surface profile RMS is better than 0.03λ, which establishes a good basic frequency band error distribution for subsequent polishing.

[0035] Step 4: Rough polishing with robotic arm

[0036] The surface roughness of the turned silicon lens is approximately 10–20 nm, eliminating the need for grinding and allowing for direct polishing. Lens polishing tool heads are integrated into mature industrial robot platforms, such as those from ABB and KUKA. An R25–R35 mm airbag polishing tool head is used to rapidly remove a large amount of surface damage after turning. Cerium oxide polishing slurry is used, with polishing particles of 1.5–2 μm in size. The polishing pad is made of polyurethane with added cerium oxide additives, reducing the depth of the surface damage layer from 5–15 μm to submicron levels. Then, a dual-frame, wheel-driven polishing tool head with a radius of R25–R30 mm is used. Cerium oxide polishing slurry is used, with polishing particles no larger than 1 μm in diameter. An additive-free polyurethane polishing pad is used to polish aspherical surfaces. Once the surface is polished to a value better than λ / 20 rms and the mid-to-high frequency residual is better than 0.02 λ rms, it can proceed to the subsequent robotic arm fine polishing stage.

[0037] Step 5: Precision polishing with robotic arm

[0038] The surface finish finishing process is still carried out using robotic polishing equipment. This step mainly addresses surface scratches, pinholes, and other processing defects left over from the previous step to control the surface finish. The polyurethane polishing pads of the wheel-type polishing tool head are replaced with damping cloth polishing pads, and the polishing fluid is a silicone liquid with polishing particles of 50-100nm. The polishing pressure and speed are reduced to uniformly smooth the surface of the mirror, achieving a conformal polishing effect. Once the surface finish meets the requirements, the process moves to the ion beam fine polishing stage.

[0039] Step Six: Ion Beam Polishing

[0040] Ion beam polishing technology was applied, and parameters such as argon flow rate, RF power, ion beam voltage, accelerating voltage, and ion source distance were optimized. The removal function was also optimized to ensure that its frequency band removal capability matched the frequency band characteristics of the aspherical surface to be processed. Multiple processing iterations were set to avoid the decrease in surface roughness of the single-crystal silicon due to temperature accumulation during long single-round processing.

[0041] Preferably, the argon flow rate of the ion source is 5-10 sscm, the radio frequency power is 80-100W, the ion beam voltage is 1050-1150V, the accelerating voltage is 200-250V, the neutralization current is 50-60mA, and the ion source distance is 50-60mm.

[0042] Example

[0043] Figure 2 This is a typical silicon aspherical lens in this embodiment of the invention. The material is single-crystal silicon, and the grade is optical. The effective aperture of the concave surface (surface 2) is 260 mm, and the surface profile is a tenth-order aspherical, expressed as follows:

[0044] The expression for the aspherical shape of the concave surface is:

[0045]

[0046] in, For the vertex curvature, R0 = -1316.93 mm; K = -e 2 =0 is the constant of the quadratic curve;

[0047] The coefficients of each higher-order term are: A4 = -2.1489e -9 A6 = 1.5077e -15 A8 = 2.3095e -19 A10 = 0.5879e -20 .

[0048] The convex surface (surface 1) is a sphere with a vertex radius of curvature R1 = 430.88 mm.

[0049] The requirements are that the surface accuracy of both sides is better than λ / 50rms, the fitting residual of 36 Zernike coefficients is better than 0.02λrms, the curvature radius error of the aspherical vertex is better than 1μm, and the thickness difference of the lens caused by optical axis deviation is better than 10μm.

[0050] The specific steps according to the various process methods described in this invention are as follows:

[0051] Step 1: Blanking the mirror blank

[0052] The outer diameter of the lens is 270mm. The monocrystalline silicon blank is rolled and cut using rough processing equipment such as a cutting machine. A 0.5mm allowance is reserved on one side of the outer circle and a 1mm allowance is reserved in the center thickness. The final cylindrical lens blank has a size of Φ271mm and a thickness of 30.89mm.

[0053] Step 2: Mirror blank forming and surface milling

[0054] The mirror blank is placed on the milling machine platform. Using the initial cylindricity of the outer circle and the bottom surface of the blank as adjustment references, the part is fastened. Then, the upper surface is milled using a milling wheel. The flatness error after milling can reach 10μm. At this time, the blank is flipped over and used as the bottom surface of the lens. The milling and shaping of lens surface 2 (concave surface) begins. Since surface 2 is a high-order aspherical surface, a 3D model is created based on the parameters of the aspherical surface equation, and the aspherical surface is directly milled in one step. Because this avoids the traditional process of milling the best-fit spherical surface and then converting it to an aspherical surface, a high aspherical surface milling accuracy can be achieved (the surface shape accuracy after milling is controlled within 30μm PV). At the same time, the surface shape contour of the milled aspherical surface is relatively smooth, which lays a good process foundation for subsequent frequency band error control.

[0055] After milling surface 2 is completed, it is flipped over for further milling until the convex spherical surface is finished. The radial outer edges of the milled convex and concave sides have parallel platform surfaces. Using plane B on the concave side as a reference, a milling coordinate system is established to machine the outer circle of the lens. During the milling process, the tolerances of various geometric parameters are controlled to meet design requirements: cylindricity error better than 3μm, flatness error better than 5–10μm, and parallelism error between the convex platform surface and the plane B reference better than 5μm.

[0056] Step 3: Single-point diamond turning

[0057] A good lens shape reference has been established during the milling process. In the single-point diamond turning stage, the aspherical concave surface is turned first. Specifically, the flatness accuracy of the B reference platform surface is improved first, and its flatness error is turned to within 2μm. The outer circle of the lens and the platform surface on the convex or concave side are used as the mounting reference, and then the aspherical concave surface is turned. After the aspherical concave surface is turned, the spherical convex surface is then turned.

[0058] The process link between turning and polishing is established by frequency band error feature matching. In traditional processes, these two parts are separate, which leads to the problem that the turned surface often needs to be repeatedly processed in the polishing stage, resulting in resource waste and repeated surface shaping. Therefore, a Gaussian function high-pass filtering method is used here for the first stage of control in the turning stage. Figure 3The figure shows a typical surface machining error distribution after turning, mainly exhibiting low-frequency surface errors. This is due to the error in the radius of curvature of the aspherical vertex caused by tool wear during the turning process, resulting in a large POWER error. Therefore, the tool parameters and process parameters for single-point diamond turning are selected and optimized. A natural single-point diamond turning tool with a 2mm radius and circular cutting edge is chosen, with a rake angle of -25°, a clearance angle of 10-15°, and a waviness of 250nm. The radial step distance of the single-point diamond is set to be no less than 0.005mm, the spindle speed is reduced to 1500rpm, and the feed depth is adjusted to the range of 5-8μm based on the damage layer of the single-crystal silicon surface. The feed rate is reduced to F 2.5mm / min. Then, the surface error after turning is detected until the result after applying a Gaussian function high-pass filter (frequency band ≥18mm) is better than 0.03λrms. The typical morphological feature distribution is shown below. Figure 4 As shown.

[0059] Step 4: Rough polishing with robotic arm

[0060] The single-crystal silicon aspherical lens that has entered the rough polishing stage of the robotic arm has a surface accuracy of about λ / 5rms. The surface is evenly distributed with damage layers of different depths. The depth of the damage layers is radially distributed. Observation by laser confocal microscopy shows that the damage layers cause pit defects, with the deepest depth being about 10 to 15 μm.

[0061] First, on the robotic polishing platform, an integrated airbag polishing tool head is used. An R30mm airbag is selected for extraction and optimization of the corresponding removal function. The process parameters are set as follows: pressure 10N, actual output 25N, and rotation speed 120rpm. Cerium oxide polishing fluid is used, with polishing particles of 1.5μm. The polishing pad is made of polyurethane material with added cerium oxide additives. A removal function covering a removal area of ​​15-23mm is selected. Airbag polishing is performed on the monocrystalline silicon aspherical lens. After processing, the subsurface damage layer area of ​​the mirror is observed. The process ends when the subsurface damage layer depth reaches the submicron level.

[0062] Then, the wheel-type polishing tool head was replaced with a polishing wheel of R25mm. The process parameters were set to a pressure of 8N, an actual output of 20N, and a rotation speed of 100rpm. Cerium oxide polishing fluid was used, but the diameter of the polishing particles was reduced to 1μm. An additive-free polyurethane polishing pad was selected. The corresponding removal function was extracted and optimized. The removal function that could cover a removal area of ​​10-15mm was selected. The local errors of the mirror surface were corrected until the surface shape accuracy of both sides was better than 0.05λrms and the mid-to-high frequency residual was better than 0.02λrms. The processing was then completed.

[0063] Step 5: Precision polishing with robotic arm

[0064] Continuing on the robotic arm processing platform, a wheel-type polishing tool head was used, and the polishing pad was replaced with a softer damping cloth. The process parameters were set as follows: pressure 6N, rotation speed 60rpm, and polishing fluid 100nm silicone liquid. Depending on the imperfections on the polished mirror surface, different dilution ratios were applied, generally between 1:5 and 1:10, while controlling the pH value within the range of 9.5-10. The surface of the silicon aspherical lens polished by the robotic arm was then finished, including removing scratches, pitting, and other surface defects. After processing, the lens was inspected using a 60-100 watt incandescent lamp against a black background using a 4-6x magnifying glass. This process was repeated until the surface finish of the silicon lens reached Grade IV requirements, at which point processing was complete.

[0065] Step Six: Ion Beam Processing

[0066] After the aforementioned processing steps, the surface finish of the aspherical silicon lens meets the final requirements, with a surface accuracy within the range of approximately 0.04–0.05 λrms. The ion beam polishing process parameters are optimized to obtain a removal function that can quickly eliminate surface errors from the previous mirror stage. Here, the parameters are set as follows: argon flow rate 8 sscm, RF power 85W, ion beam voltage 1100V, accelerating voltage 250V, neutralization current 50mA, and ion source distance 50mm. The resulting removal function has a half-width at half-maximum (FWHM) of 4.5mm, which can remove frequency band errors with a characteristic size of over 10mm from the aspherical silicon lens surface. After 1-2 rounds of ion beam processing, the final processing is completed.

[0067] Following the process methods and control points described in steps 1 to 6, the single-crystal silicon aspherical lens processed in the final embodiment has a surface accuracy of 0.02λrms for both the aspherical and convex spherical surfaces, a curvature radius error of 1μm at the vertex of the aspherical surface, a thickness difference of 5μm, a surface roughness of 2nm, and a surface finish grade of IV. The processing accuracy and quality are far superior to the industry average.

[0068] The present invention has been described in detail above with reference to specific embodiments and exemplary examples; however, these descriptions should not be construed as limiting the present invention. Those skilled in the art will understand that various equivalent substitutions, modifications, or improvements can be made to the technical solutions and embodiments of the present invention without departing from the spirit and scope of the invention, and all such modifications and improvements fall within the scope of the present invention. The scope of protection of the present invention is defined by the appended claims.

[0069] The contents not described in detail in this specification are common knowledge to those skilled in the art.

Claims

1. A highly efficient processing method for large-size infrared aspherical silicon lenses, characterized in that, Includes the following steps: According to the design requirements of the drawings, the monocrystalline silicon lens blank is cut into cylindrical lens blanks with machining allowance. The outer cylindrical surface, convex side and concave side platform surface, spherical convex surface and aspherical concave surface of the mirror blank are milled using a milling machine; Using a single-point diamond lathe, with the outer circle and either the convex or concave side of the lens as the mounting reference, the aspherical lens after milling is successively machined into aspherical concave surface and spherical convex surface; the high-frequency residual of the surface profile RMS after machining is better than 0.03λ under 15-20mm Gaussian high-pass filtering. A robotic arm with an integrated polishing tool head performs rough polishing and surface profile smoothing on the surface of the turned silicon lens. After the surface profile is polished to a value better than λ / 20 and the RMS mid-to-high frequency residual is better than 0.02λ, the lens is then transferred to the robotic arm for fine polishing. After precision polishing by the robotic arm, ion beam polishing technology is used to optimize the parameters of argon flow rate, radio frequency power, ion beam voltage, acceleration voltage, and ion source distance of the ion source, and to optimize the removal function so that its frequency band removal capability matches the frequency band characteristics of the aspherical surface to be processed. After ion beam polishing, the processing of the infrared aspherical silicon lens is completed. The step of milling the outer cylindrical surface, convex side, and concave side of the mirror blank, as well as the spherical convex surface and the aspherical concave surface, using a milling machine is implemented in the following manner: Using the initial outer cylindricity and bottom surface of the mirror blank as adjustment references, the upper surface of the mirror blank is milled, and the flatness error of the upper surface is machined to within 10μm after milling. On the basis of completing the machining of the upper surface of the mirror blank, the concave and convex surfaces of the lens are milled on the bottom and upper surfaces respectively. The radial outer edges of the convex and concave sides after milling have parallel platform surfaces. Using any platform surface as a reference, a milling coordinate system is established to perform precision machining on the outer cylindrical surface of the lens. The step of rough polishing the surface of the turned silicon lens using a robotic arm with an integrated polishing tool head is implemented as follows: First, an R25-R35mm airbag polishing tool head is used to remove the excess material from the damaged layer on the turned surface. Cerium oxide polishing fluid is used, the polishing particle size is 1.5-2μm, and the polishing pad is made of polyurethane material with added cerium oxide additives. This reduces the depth of the damaged layer on the turned surface from 5-15μm to submicron. Then, a dual-frame wheel-driven wheel polishing tool head with a radius of R25-R30mm is applied. Cerium oxide polishing fluid is used, the polishing particle diameter is no greater than 1μm, and an additive-free polyurethane polishing pad is selected. The aspherical surface is polished until the surface is polished to a value better than λ / 20. The precision polishing step of the robotic arm is implemented in the following manner: a wheel polishing tool head with dual-frame wheel drive is used, a damping cloth polishing pad is used, and the polishing liquid is a silicone liquid with a polishing particle size of 50-100nm, so as to uniformly smooth the surface of the mirror.

2. The efficient processing method for large-size infrared aspherical silicon lenses according to claim 1, characterized in that, In the step of milling the outer cylindrical surface, convex side and concave side platform surface, spherical convex surface and non-spherical concave surface of the mirror blank using a milling machine, the cylindricity error after milling is better than 10μm, the flatness error of the convex side and concave side platform surface is better than 10μm, and the parallelism error of the convex side and concave side platform surface is better than 10μm.

3. The efficient processing method for large-size infrared aspherical silicon lenses according to claim 1, characterized in that, Before performing the aspherical concave surface and spherical convex surface turning steps on the milled aspherical lens, the flatness accuracy of the platform surface on the convex or concave side is turned to within 2μm.

4. The efficient processing method for large-size infrared aspherical silicon lenses according to claim 1, characterized in that, In the step of turning the aspherical concave surface of the milled aspherical lens, the turning process parameters include: spindle speed 1500~3500rpm, feed rate 2.5~10mm / min, feed depth 3~10μm, and radial step spacing 0.005~0.01mm.

5. The efficient processing method for large-size infrared aspherical silicon lenses according to claim 1, characterized in that, In the step of turning the aspherical concave surface of the milled aspherical lens, a natural diamond circular arc tool is used, and the tool parameters include: rake angle -25°, clearance angle 10~15°, arc radius 1~1.5mm, and waviness 100nm-250nm.

6. The efficient processing method for large-size infrared aspherical silicon lenses according to claim 1, characterized in that, In the ion beam polishing step, the argon gas flow rate of the ion source is 5-10 sscm, the radio frequency power is 80-100W, the ion beam voltage is 1050-1150V, the accelerating voltage is 200-250V, the neutralizing current is 50-60mA, and the ion source distance is 50-60mm.

7. The efficient processing method for large-size infrared aspherical silicon lenses according to claim 1, characterized in that, The large-size infrared aspherical silicon lens has dimensions of Φ100~Φ500mm.

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