An ultra-thin optical element polishing process and device

Abstract

The application relates to the technical field of optical polishing, and particularly discloses a polishing process and equipment for ultrathin optical elements, wherein a first surface of an ultrathin optical element is connected to a separator through a plurality of mutually separated pitch bonding parts, polishing liquid is added between a second surface and a modified pitch polishing film, and fine polishing is carried out to obtain a stage polishing piece; the stage polishing piece is moved away from the pitch polishing film and placed in a constant-temperature environment for standing, and then is reattached to the pitch polishing film for single fine polishing, and the single fine polishing and the constant-temperature standing are alternately carried out; after the fine polishing is completed, low-temperature discing and low-temperature cleaning are carried out, and the separated ultrathin optical element is placed in the constant-temperature environment for standing. The process reduces the surface shape change caused by bonding constraints, polishing pressure and temperature change through dispersed bonding, stage release processing and low-temperature discing, and reduces the deviation between the surface shape in the processing state on the disc and the surface shape in the free state after the bonding is released.

Description

Technical Field

[0001] This application relates to the field of optical polishing technology, and more specifically, to a polishing process and equipment for ultra-thin optical components. Background Technology

[0002] Ultrathin optical elements refer to lenses, windows, filters, or mirror substrates with a relatively small thickness relative to their aperture and low overall bending stiffness. During precision polishing, these elements are easily affected by clamping constraints, processing pressure, frictional temperature rise, and residual material stress. Their surface shape under load may differ from their free state shape after being released from processing constraints. Therefore, the processing quality of ultrathin optical elements depends not only on the material removal result but also on whether the elastic deformation formed during processing can be stably released after processing.

[0003] Existing techniques typically involve first fixing the ultrathin optical element onto a support fixture, then bringing the surface to be processed into contact with a polishing tool. The surface shape is gradually corrected through continuous grinding or polishing, and the processing result is assessed while the workpiece remains fixed. Because the workpiece is simultaneously subjected to both fixing constraints and polishing loads during processing, the detected surface shape includes stress deformation. When processing is completed and the fixing constraints are released, the previously accumulated elastic deformation and residual stress gradually release, causing the element surface to spring back, resulting in a deviation between the surface shape in the processed state and its free state.

[0004] To mitigate these deviations, existing processes typically control component deformation by reducing processing pressure, decreasing the amount of material removed per cycle, increasing the stiffness of the bearing fixture, or extending the stabilization time after processing. However, reducing processing pressure and decreasing the amount of material removed prolongs the processing cycle, while increasing the stiffness of the bearing fixture strengthens the constraint of the fixed boundary on the ultrathin optical component. Simply extending the stabilization time cannot eliminate the stress deformation already formed during processing. Therefore, existing technologies still suffer from the problem of maintaining consistency between the surface shape of the ultrathin optical component in the processed state and its free state after the processing constraints are removed. Summary of the Invention

[0005] The main purpose of this application is to solve the technical problem that the surface shape in the processing state of existing ultra-thin optical element polishing processes is difficult to keep consistent with the surface shape in the free state after the processing constraints are removed.

[0006] To address the aforementioned problems, this application proposes a polishing process for ultra-thin optical components, comprising: S1. The first surface of the ultra-thin optical element is bonded to the receiving surface of the separator through multiple asphalt bonding parts that are separated from each other, and the second surface is away from the separator to obtain the upper plate. S2. Add polishing liquid between the second surface and the prepared tar polishing film, and then apply the tar polishing film to the second surface for fine polishing to obtain a staged polished part. S3. Remove the staged polished parts from the asphalt polishing film and allow them to stand at a constant temperature. Then, attach the staged polished parts back onto the asphalt polishing film after standing. Alternately perform single fine polishing and constant temperature standing to obtain finely polished parts. S4. Perform low-temperature cooling and low-temperature cleaning on the polished part, and place the ultra-thin optical element separated from the separator in a constant temperature environment.

[0007] This application also discloses an ultra-thin optical element polishing device, including a base, a polishing disk rotatably disposed in the middle of the base, and an annular tar polishing film being laid on the upper surface of the polishing disk; The base is provided with a correction disk and a planetary wheel mirror disk. The correction disk and the planetary wheel mirror disk are located above the annular tar polishing film and are distributed at intervals along the circumference of the annular tar polishing film. The working surface of the correction disk and the working end of the planetary wheel mirror disk face the annular tar polishing film respectively. A separator is detachably provided inside the planetary wheel mirror disk. The separator has a receiving surface facing the annular tar polishing film. The ultra-thin optical element is connected to the receiving surface through multiple tar adhesive parts that are separated from each other. The surface of the ultra-thin optical element facing away from the separator faces the annular tar polishing film. The base is provided with a polishing fluid pipe, and the outlet end of the polishing fluid pipe faces the contact area between the ultra-thin optical element and the annular asphalt polishing film.

[0008] Beneficial effects: This application connects ultrathin optical elements to a separator using multiple separated tar bonding sections, distributing the bonding effect across multiple locations. The fluidity and deformation capacity of tar at processing temperatures buffer localized bonding, reducing forced bending of the ultrathin optical elements due to continuous constraint. During fine polishing, a stable contact is formed between the prepared tar polishing film and the second surface. Abrasive particles in the polishing fluid slide along with both, removing surface material, while the tar polishing film buffers localized contact pressure. After a single fine polishing cycle, the ultrathin optical element maintains its bond with the separator and is removed from the tar polishing film. Constant-temperature resting gradually attenuates the transient deformation and temperature changes caused by fine polishing. Alternating between fine polishing and constant-temperature resting reduces the continuous accumulation of processing effects. After fine polishing, the tar bonding is released and tar residue is removed under low-temperature conditions. The ultrathin optical element is then placed at a constant temperature, thereby reducing surface changes caused by temperature variations and bond release during the lowering and cleaning processes.

[0009] In summary, this application can reduce the deviation between the surface shape in the processed state on the disc and the surface shape in the free state after the adhesive is released, and reduce the possibility of surface shape deviation caused by the rebound of the lower disc. Attached Figure Description

[0010] Figure 1 This is a schematic diagram of the overall steps of a polishing process for an ultra-thin optical element according to this application; Figure 2 This is a schematic diagram of the overall structure of an ultra-thin optical element polishing device according to this application; Figure 3 yes Figure 2 Enlarged structural diagram at point A in the diagram; Figure 4 yes Figure 2 Enlarged structural diagram at point B in the diagram; Figure 5 This is a schematic diagram of the planetary wheel mirror disk in an ultra-thin optical element polishing device according to this application; Figure 6 This is a schematic diagram of the asphalt bonding part in an ultra-thin optical element polishing device according to this application; Figure 7 This is a schematic diagram of the full-aperture surface shape of the initial surface shape after unloading and the stable surface shape after settling, in an optional embodiment of this application; Figure 8 This is a schematic diagram of the curves of the initial surface shape after unloading and the stable surface shape after standing in an optional embodiment of this application, along the measurement section.

[0011] The attached figures are labeled as follows: 1. Base; 11. Polishing disc; 12. Annular tar polishing film; 2. Correction disc; 3. Planetary wheel mirror disc; 4. Separator; 41. Receiving surface; 5. Tar bonding part; 6. Ultra-thin optical element; 7. Polishing fluid pipe; 8. First drive assembly; 81. First motor; 82. First driving wheel; 83. First driven wheel; 9. Second drive assembly; 91. Second motor; 92. Second driving wheel; 93. Second driven wheel.

[0012] The realization of the purpose, functional features and advantages of this application will be further explained in conjunction with the embodiments and with reference to the accompanying drawings. Detailed Implementation

[0013] To make the objectives, technical solutions, and advantages of this application clearer, the following detailed description is provided in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the scope of this application.

[0014] Those skilled in the art will understand that, unless explicitly stated otherwise, the singular forms “a,” “an,” “the,” and “the” used herein may also include the plural forms. It should be further understood that the term “comprising” as used in the specification of this application means the presence of features, integers, steps, operations, elements, modules, and / or components, but does not exclude the presence or addition of one or more other features, integers, steps, operations, elements, modules, components, and / or groups thereof. It should be understood that when an element is referred to as “connected” or “coupled” to another element, it may be directly connected or coupled to the other element, or there may be intermediate elements. Furthermore, “connected” or “coupled” as used herein may include wireless connections or wireless coupling. The term “and / or” as used herein includes all or any modules and all combinations thereof of one or more associated listed items.

[0015] Those skilled in the art will understand that, unless otherwise defined, all terms used herein (including technical and scientific terms) have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains. It should also be understood that terms such as those defined in general dictionaries should be understood to have the same meaning as in the context of the prior art, and should not be interpreted in an idealized or overly formal sense unless specifically defined as herein.

[0016] Reference Figure 1-8 This application provides a polishing process for ultra-thin optical components, including the following steps: S1: The first surface of the ultrathin optical element is bonded to the receiving surface of the separator through multiple tar adhesive parts that are separated from each other, and the second surface is away from the separator to obtain the upper plate.

[0017] In step S1, a separator is selected to match the dimensions, thickness, material type, and surface shape requirements of the ultra-thin optical element to be processed. The separator has a receiving surface facing the ultra-thin optical element. Before mounting, the receiving surface of the separator is cleaned and degreased to remove particles, oil, and residual moisture, preventing impurities from getting stuck in the tar bonding area and causing localized lifting. At the same time, the ultra-thin optical element is cleaned and dried, and its two surfaces are designated as the first surface and the second surface, respectively. The first surface faces the separator and bears the bonding, while the second surface remains exposed and serves as the fine polishing surface.

[0018] A bonding area corresponding to the contour of the first surface is defined on the receiving surface of the separator, and multiple separated asphalt bonding portions are formed within the bonding area. These asphalt bonding portions can be formed by methods such as dripping, spot coating, pre-prepared asphalt transfer, or molding. Spacing is maintained between adjacent asphalt bonding portions to avoid forming a continuous asphalt layer covering the first surface. The number and distribution range of the asphalt bonding portions are determined based on the aperture, thickness, and bending stiffness of the ultra-thin optical element, ensuring that each bonding position provides dispersed support to the first surface.

[0019] The selected asphalt maintains its bonded state at room temperature and enters a plastic state at the upper plate temperature. The upper plate temperature is determined based on the softening characteristics of the asphalt, ideally allowing the asphalt to deform and wet the first surface under pressing without significant free flow. After softening, multiple asphalt samples are flattened so that their ends facing the first surface are located on substantially the same supporting plane. The ultrathin optical element is then moved above the separator, with its first surface facing the asphalt bonding area, and the geometric center of the ultrathin optical element aligned with the center of the bonding area.

[0020] During the pressing process, pressure is gradually applied to establish contact between multiple asphalt bonding portions and the first surface, and to restrict the lateral slippage of the ultra-thin optical element relative to the separator. After pressing is completed, the temperature is gradually reduced while keeping the relative position of the ultra-thin optical element and the separator unchanged, so that the asphalt changes from a plastic state to a high-viscosity or solidified state that can maintain its shape. This forms multiple separated asphalt bonding portions connecting the first surface and the receiving surface of the separator, resulting in the upper plate.

[0021] Because the multiple asphalt bonding parts are separated from each other, a continuous integral bonding interface is not formed between the first surface and the separator; at the same time, asphalt has a certain flow and deformation capacity at the processing temperature. When the forces acting on different bonding positions are different, the corresponding asphalt bonding parts can produce local deformation, thereby reducing the overall traction of the ultra-thin optical element caused by continuous bonding.

[0022] S2: Add polishing liquid between the second surface and the prepared tar polishing film, and then apply the tar polishing film to the second surface for fine polishing to obtain a staged polished part.

[0023] In step S2, an asphalt polishing film is laid on the working area of ​​the polishing disc, covering the fine-polishing area traversed by the second surface of the ultra-thin optical element, and its surface shape is adjusted by a correction disc before fine polishing. After adjustment, the surface of the asphalt polishing film is cleaned to remove asphalt debris and other particles formed during the adjustment process, and then a polishing liquid compatible with the material of the ultra-thin optical element is added to the working area of ​​the asphalt polishing film.

[0024] The polishing slurry comprises a liquid medium and fine polishing particles dispersed therein, the type of which is selected based on the material of the ultra-thin optical element. The supply amount of polishing slurry is based on maintaining a continuous wettability between the second surface and the asphalt polishing film, ensuring that the slurry covers the actual contact area while removing grinding debris and some frictional heat generated during processing. The supply amount is increased when localized lack of slurry or a tendency towards dry grinding occurs in the contact area; conversely, the supply amount is reduced when excessive slurry buildup affects the stable contact between the second surface and the asphalt polishing film.

[0025] The upper plate is installed into the corresponding processing position, so that the second surface gradually approaches the tar polishing film. Wetting contact is first formed through the polishing fluid, and then the working contact required for fine polishing is established. The contact pressure is set according to the thickness, diameter and bending stiffness of the ultra-thin optical element to maintain stable contact of the second surface, while limiting the significant bending of the ultra-thin optical element due to axial pressure.

[0026] During the fine polishing process, the upper disc rotates, causing the second surface to slide relative to the tar polishing film. Each area of ​​the second surface sequentially passes through the working area of ​​the tar polishing film, and the fine particles in the polishing fluid remove trace amounts of material from the second surface under contact pressure and sliding action. The movement speed of the upper disc is set according to the state of the tar polishing film, the supply of polishing fluid, and the material removal rate, ensuring that there is no significant vibration, localized dry grinding, or excessive splashing of polishing fluid during the fine polishing process.

[0027] The single polishing time is set based on the remaining machining allowance on the second surface and a predetermined material removal rate. The total polishing process is divided into multiple single polishing passes, rather than removing all machining allowance in a single continuous process. Polishing fluid is continuously supplied during each single polishing pass to maintain stable wetting between the second surface and the tar polishing film. After each single polishing pass, the second surface is gradually detached from the tar polishing film, resulting in a staged polished part that still maintains the adhesion between the ultra-thin optical element and the separator.

[0028] S3: Remove the staged polished part from the tar polishing film and allow it to stand at a constant temperature. Then, attach the staged polished part back to the tar polishing film after standing. Alternately perform single fine polishing and constant temperature standing to obtain a finely polished part.

[0029] In step S3, after the stage polishing part completes one single fine polishing, the asphalt bonding relationship between the first surface of the ultra-thin optical element and the separator is not released. Instead, the overall upper plate state consisting of the separator, the asphalt bonding part and the ultra-thin optical element is maintained, and the stage polishing part is moved away from the asphalt polishing film.

[0030] When removing the second surface, first stop the sliding between the second surface and the tar polishing film, then gradually release the contact between the two, allowing the second surface to smoothly detach from the tar polishing film. If polishing liquid remains on the second surface, allow the excess polishing liquid to flow away naturally, reducing the additional load on the ultra-thin optical element caused by local blowing, wiping, or other operations.

[0031] After the polished part is removed from the processing position, the upper plate is placed in a constant temperature environment with stable temperature and minimal vibration, using the separator as the overall support base. During the resting period, the second surface is not subjected to polishing pressure, adsorption pressure, or local clamping force, and the tar adhesion between the ultra-thin optical element and the separator remains unchanged. Thus, without re-establishing the adhesive boundary, the contact pressure, frictional temperature rise, and transient changes caused by material removal generated by a single fine polishing operation gradually decrease.

[0032] The constant temperature environment is matched with the fine polishing environment temperature to prevent significant temperature changes when the polished parts transition from the fine polishing state to the resting state. The resting time is determined based on the material, thickness, and diameter of the ultra-thin optical element, the viscoelastic properties of the asphalt, and the temperature rise generated by a single fine polishing. The basic resting time can be determined during the process development stage using test pieces of the same specifications.

[0033] After settling, check the asphalt adhesion between the ultra-thin optical element and the separator, as well as the cleanliness of the second surface. When the upper plate is in normal condition, reinstall the separator in the corresponding processing position, so that the second surface faces the asphalt polishing film again, and add polishing fluid again for another single fine polishing. This forms a cycle of single fine polishing, removal of the asphalt polishing film, constant temperature settling, and fine polishing again.

[0034] The number of cycles is determined based on the total machining allowance and the amount of material removed in a single polishing pass. As the machining endpoint approaches, the amount of material removed in a single pass can be reduced accordingly. After multiple single polishing passes and constant-temperature settling, a polished part is obtained that remains connected to the separator via the asphalt bonding section.

[0035] The constant temperature settling step in this process serves as an intermediate step in the polishing process, allowing the transient deformation caused by the previous polishing to be alleviated before the next polishing, thereby reducing the continuous accumulation of processing effects during continuous processing.

[0036] S4: Perform low-temperature cooling and cleaning on the polished parts, and place the ultra-thin optical elements separated from the separator in a constant temperature environment.

[0037] In step S4, after all single polishing and intermediate constant temperature resting are completed, the polished part is removed as a whole from the polishing position and transferred to the lower platen station. The low temperature in the lower platen refers to avoiding rapid softening of the asphalt through local high temperatures significantly higher than the processing environment temperature, thereby reducing the instantaneous temperature gradient generated during the lower platen process of the ultra-thin optical components.

[0038] The temperature of the lower plate is determined based on the softening characteristics of the asphalt bonding area, allowing the asphalt bonding strength to gradually decrease while limiting significant thermal deformation of ultra-thin optical components and separators due to temperature changes. The polished parts can be brought to a temperature close to that of the lower plate environment first, and then the multiple asphalt bonding areas can be gradually softened through gentle temperature changes or the action of a medium.

[0039] When the asphalt-bonded portion reaches a state where it can deform under relatively small separation forces, the first surface of the ultrathin optical element gradually separates from the receiving surface of the separator. During the separation process, avoid applying large vertical prying forces to local locations of the ultrathin optical element, allowing the separation interface to gradually expand until the ultrathin optical element is completely detached from the separator.

[0040] After the bottom plate is installed, some tar may remain on the first surface. The ultra-thin optical element is then transferred to a low-temperature cleaning solution with a temperature close to that of the bottom plate environment to soften, swell, or detach the residual tar from the first surface. The residual tar is then removed by liquid flow, gentle agitation, or non-contact rinsing, avoiding scraping the first surface with hard tools.

[0041] After removing the tar, the cleaning solution and residual contaminants can be removed using a clean rinsing medium at a temperature close to that of the cleaning solution, allowing the ultrathin optical components to gradually return to the temperature of the constant-temperature static environment. After completing the low-temperature cleaning, the ultrathin optical components are transferred to a clean, low-vibration constant-temperature environment for static placement. At this point, neither the first nor the second surface is constrained by the tar adhesion or the fine-polishing contact pressure, and the ultrathin optical components are in a free state.

[0042] The settling time is determined based on the material, thickness, and aperture of the ultra-thin optical element, as well as the temperature changes generated during the lowering and cleaning process, so that the ultra-thin optical element can complete temperature equalization and further release of residual effects after the asphalt bonding is removed.

[0043] In summary, this application first connects the first surface of the ultrathin optical element to the separator through multiple separated tar bonding sections, keeping the ultrathin optical element in an upper plate state and exposing the second surface. Then, the second surface is brought into contact with a prepared tar polishing film, and trace amounts of material are removed through sliding between the two under the action of the polishing fluid. After a single fine polishing, without releasing the tar bonding between the ultrathin optical element and the separator, the staged polished part is removed from the tar polishing film and placed at a constant temperature for static treatment. Then, a single fine polishing is performed again. This alternation between single fine polishing and constant temperature static treatment gradually releases the transient deformation generated during processing. After fine polishing, the tar bonding between the ultrathin optical element and the separator is released at low temperature, followed by low-temperature cleaning and constant temperature static treatment, thereby reducing the change between the surface shape in the processed state and the free state surface shape after the bonding constraints are released.

[0044] In another alternative embodiment, the first surface of the ultrathin optical element is connected to the separator via multiple spaced-apart tar adhesive portions. After the second surface completes the nth single polishing pass, the entire staged polished part is removed from the tar polishing film, while maintaining the connection between the ultrathin optical element, the tar adhesive portions, and the separator. While the staged polished part is still attached to the tar polishing film and has not yet undergone a constant-temperature settling period, the surface shape data of the second surface is measured using a surface shape detector and recorded as the initial unloading surface shape W. n，0 The polished parts were then placed horizontally in a constant temperature environment and left to stand for a time t. s This allows the transient effects caused by contact pressure, surface sliding, frictional temperature rise, and viscoelastic deformation of the asphalt bond during a single polishing process to gradually dissipate. After the settling period, the surface shape data of the second surface are measured again and recorded as the stable surface shape W. n，s .

[0045] The two surface shape measurements were completed under the same effective aperture, the same support posture, and the same sampling area, and W was used to measure the surface shape. n，0 With W n，s Registered to the same surface coordinate system, the rigid body components caused by overall translation, tilting, and measurement position offset are subtracted. The unloading surface relaxation amount R corresponding to the nth single fine polishing is... n Determine by the following formula: ; In the formula, The value represents the point-by-point height difference distribution of the second surface before and after constant temperature rest, and RMS represents the root mean square value of the point-by-point height difference distribution. In addition to the root mean square value, the surface relaxation state can also be characterized by the peak and valley values ​​of the surface shape difference data, or by at least one of the changes in the defocus term, astigmatism term, and coma term obtained by Zernike polynomial fitting.

[0046] Relaxation threshold R th The allowable surface shape error of ultra-thin optical elements is determined and calibrated using processing data from samples of the same material, thickness, and diameter. When R... n >R th At this time, instead of using a low-temperature lower plate, reduce the contact pressure of another single fine polishing, shorten the single fine polishing time, extend the constant temperature standing time, or re-adjust the asphalt polishing film, and then reattach the staged polished parts to the asphalt polishing film for fine polishing.

[0047] When R n ≤R th However, if the stable surface shape is not yet within the target surface shape range, perform another single polishing pass on the second surface; when the stable surface shape... Located within the target surface area and R n ≤R thWhen the processing status meets the preset termination conditions, it is determined that the processing status meets the preset termination conditions. Preferably, after the relaxation amount of the stable surface shape and the unloading surface shape corresponding to two consecutive single polishing operations meets the preset termination conditions, low-temperature unloading and low-temperature cleaning are then performed.

[0048] Specifically, refer to Figure 7 and 8 The surface shape change of ultrathin optical elements after a single polishing cycle was quantitatively characterized. After the nth polishing cycle, the polished part was removed entirely from the tar polishing film while maintaining the tar adhesion between the ultrathin optical elements and the separator. The effective aperture of the second surface of the ultrathin optical elements was measured for the first time using a surface shape measuring instrument, and the results were as follows: Figure 7 The initial unloading surface shape W shown on the left n，0 . Figure 7 The contour lines correspond to the surface height distribution at different locations on the second surface. The peak and valley values ​​of the initial surface shape are denoted as P1, and the root mean square value is denoted as R1. After the first measurement, the polished part is placed in a constant temperature environment for a set time. During the settling period, the bonding between the ultrathin optical element and the separator is not released, and the second surface is kept free from the contact pressure generated by the tar polishing film. After the settling period, the second surface is measured again under the same effective aperture, support posture, and sampling position as the first measurement, and the results are obtained. Figure 7 The stable surface shape W shown on the right n，s The peak and valley values ​​are denoted as P2, and the root mean square value is denoted as R2. The two-dimensional surface data obtained from the two measurements are registered to the same coordinate system, and the overall translation and tilt components caused by changes in measurement attitude are subtracted, so that W n，0 With W n，s The sampling positions in the data form a corresponding relationship. Figure 7 The changes in the shape of the two sets of contour lines show that the local height distribution of the second surface changed before and after being kept at a constant temperature. This change reflects the surface relaxation of the ultrathin optical element after it is removed from the tar polishing film and left to stand.

[0049] To further visually represent the changes in local surface shape before and after static placement, such as Figure 8 As shown, in Figure 7 Select the same measurement section from the full-diameter surface data, denot the section length as L, and denot each measurement position on the section as x. Figure 8 The solid line in the figure represents the initial unloading surface shape W. n，0在该 The change in height along the transverse line, with the dashed line representing the stable surface shape W. n，s The height variation along the same cross section. Based on the data shown in the figure, W n，0 The positive peak is approximately +34 nm, the negative peak is approximately -30 nm, and the peak-to-valley variation along the cutoff direction is approximately 64 nm; W after being kept at a constant temperature n，sThe positive peak value is approximately +17 nm, and the negative peak value is approximately -11 nm, corresponding to a peak-to-valley variation of approximately 28 nm. This indicates that, on the same measurement cross-section, the surface undulation amplitude after resting is smaller than immediately after a single polishing cycle, suggesting that the polished part undergoes a transient surface change that gradually releases over time after the tar polishing film is removed. It should be noted that... Figure 8 The cross-sectional curves mainly reflect the local trend of surface shape changes before and after static loading, and the unloading surface relaxation amount R. n Preferred according to Figure 7 The calculation is based on the two-dimensional surface data of all corresponding sampling points within the effective aperture shown, rather than solely on... Figure 8 The single intercept line in the middle is determined.

[0050] In one embodiment, before fine polishing of the ultrathin optical element, both surfaces undergo rough polishing. Before processing, abrasive particles, oil, and moisture are removed from both surfaces. The ultrathin optical element is then placed between two opposing rough polishing surfaces, with each surface facing its corresponding surface. Rough polishing fluid is added to both contact areas, and both surfaces are simultaneously rough polished. This ensures that the material removal process on both surfaces is essentially synchronized, reducing the stress imbalance in the thickness direction caused by continuous material removal on one side.

[0051] The rough polishing amount is determined based on the thickness of the damaged layer formed by the previous fine grinding and the reserved processing allowance. The amount of material removed per unit time can be determined by using a test piece of the same material, and the rough polishing time can then be set accordingly. During the processing, residual rough polishing fluid and abrasive debris are removed in stages, and the processing status of both surfaces is observed. Rough polishing ends when the fine grinding damaged layer on both surfaces has been removed. After rough polishing, the ultrathin optical element is cleaned and rinsed, and then placed horizontally in a temperature-stable environment to allow the transient changes caused by the rough polishing pressure, frictional temperature rise, and cleaning temperature difference to gradually decrease.

[0052] In one embodiment, before forming the tar bond on the receiving surface of the separator, the receiving surface is first cleaned and dried, and the bonding area is delineated according to the outer contour of the ultra-thin optical element. A gap is maintained between the edge of the bonding area and the edge of the ultra-thin optical element to reduce the possibility of tar overflow during the softening and pressing process.

[0053] The quantity and spacing of asphalt are determined based on the aperture, thickness, and bending stiffness of the ultra-thin optical element. The same batch of asphalt is divided or quantitatively sampled to form multiple asphalt blocks of similar mass, which are then evenly distributed within the bonding area, with adjacent asphalt blocks kept separate. The separator and asphalt blocks are slowly heated until the asphalt reaches a plastic state, and multiple asphalt blocks are simultaneously flattened using a flattening device, ensuring that the ends of the multiple asphalt blocks facing the first surface are on the same supporting plane.

[0054] The first surface is then oriented towards multiple asphalt materials, and the center of the ultra-thin optical element is aligned with the center of the bonding area. The first surface is then gradually pressed, allowing each asphalt material to make contact with it. The ultra-thin optical element and the separator's receiving surface are kept substantially parallel while the surface is slowly cooled. Once the asphalt has recovered to a state where it can maintain its shape, the pressing is released, forming multiple asphalt bonding portions that are separated from each other and connect the first surface of the ultra-thin optical element to the separator's receiving surface.

[0055] In one embodiment, after obtaining the upper disk, the separator is aligned with the mounting position of the planetary mirror disk, and the second surface of the ultrathin optical element is kept facing the tar polishing film. The separator is installed into the corresponding mounting area along the axial direction of the planetary mirror disk, so that the outer edge of the separator forms a stable circumferential constraint with the planetary mirror disk, reducing the possibility of circumferential slippage of the separator relative to the planetary mirror disk during the fine polishing process.

[0056] After installation, adjust the separator's position within the planetary mirror disk so that the second surface of the ultra-thin optical element aligns with the effective working area of ​​the tar polishing film, and check the separator's installation stability within the planetary mirror disk. Then, rotate the planetary mirror disk at low speed to confirm its condition. When there is no significant radial wobble in the separator and the working position of the second surface is stable, complete the fine polishing and assembly of the upper disk component.

[0057] In one embodiment, an asphalt polishing film is laid on the working surface of a polishing pad, and its thickness is determined according to the diameter of the polishing pad, the hardness of the asphalt, and the shape of the target working surface. Before laying, the working surface of the polishing pad is cleaned, and the asphalt is heated to a spreadable state and then evenly laid on the predetermined working area.

[0058] After the asphalt cools, it forms a polishing film with a certain load-bearing capacity. The working surface of the correction disc is then pressed against this film. The correction disc rotates around its central axis, and its working surface slides along the surface of the polishing film, allowing for more adjustment of any raised areas. The correction pressure and duration are determined based on the hardness of the asphalt and the initial shape of the polishing film.

[0059] When the initial height difference of the tar polishing film is large, it can be trimmed in multiple stages, removing tar debris and residual particles after each trimming. Once the contact state of the working area of ​​the tar polishing film becomes uniform, stop the rotation of the trimming disc and separate the trimming disc from the tar polishing film to obtain the trimmed tar polishing film.

[0060] In one embodiment, tar debris is removed from the surface of the tar polishing film before fine polishing, and the polishing liquid is stirred until the polishing particles are evenly dispersed. The polishing liquid is dripped from above the contact area between the second surface and the tar polishing film, forming a continuous liquid layer before they come into contact.

[0061] The upper plate is then gradually brought closer to the tar polishing film, allowing the second surface to establish contact with the tar polishing film through the polishing liquid. The contact pressure is determined based on the thickness and diameter of the ultra-thin optical element, ensuring that the second surface is stably adhered to the tar polishing film while limiting significant bending of the ultra-thin optical element under pressure.

[0062] After the upper disc rotates, the second surface slides along the surface of the tar polishing film. The polishing particles remove trace amounts of material from the second surface under contact pressure and sliding action. Polishing fluid is continuously replenished during the fine polishing process to keep the contact area moist and remove abrasive debris and processing heat. After the set single fine polishing time is reached, the second surface gradually detaches from the tar polishing film, resulting in a staged polished part.

[0063] In one embodiment, after the staged polishing part completes a single fine polishing, the second surface is smoothly detached from the tar polishing film, and then the separator, along with the ultra-thin optical element, is removed from the planetary wheel mirror disk as a whole. During the removal process, the separator is clamped or supported, but the ultra-thin optical element is not directly clamped.

[0064] After the separator is removed, the multiple tar-bonded portions between the first surface of the ultra-thin optical element and the separator maintain their original connection, ensuring that the bonding boundaries remain consistent before and after settling. The upper plate is placed horizontally in a temperature-controlled and low-vibration location, with the second surface kept free, not in contact with the settling table, and not subjected to compression or adsorption.

[0065] After the settling period, check whether the asphalt bonding part is loose. Then, reinstall the separator on the planetary wheel mirror disk in the original insertion direction, so that the second surface faces the asphalt polishing film again, and enter another single fine polishing.

[0066] In one embodiment, after the polished part is completed, it is transferred to a low-temperature lower platen station, where the temperature of all parts of the polished part is first made to be uniform. The environment of the lower platen is adjusted according to the softening characteristics of the asphalt bond, so that the asphalt bond strength gradually decreases. When the asphalt bond can deform under a small separation action, the first surface of the ultrathin optical element gradually detaches from the separator receiving surface.

[0067] After the ultra-thin optical element is separated from the separator, it is transferred into a low-temperature cleaning solution with a temperature close to that of the lower plate environment. This allows the residual tar on the first surface to gradually soften or swell, and the residue is removed by liquid flow, gentle agitation, or non-contact rinsing.

[0068] After the tar residue is removed, the cleaning fluid residue is removed by a clean rinsing medium. Then, the ultra-thin optical element is placed in a constant temperature, clean and low vibration environment and left to stand. At this time, the first and second surfaces are no longer constrained by tar adhesion or fine polishing contact pressure, so that the temperature changes and residual effects formed during the lower plate and cleaning process gradually stabilize.

[0069] refer to Figure 2-6This application also discloses an ultra-thin optical element polishing device. The base 1 is configured as a box structure with a horizontal mounting surface. A circular polishing disk 11 is provided in the middle of the base 1. The polishing disk 11 is rotatably connected to the base 1 through a rotating shaft and bearing assembly. An annular working area is formed on the upper surface of the polishing disk 11, and a continuous annular asphalt polishing film 12 is laid in the annular working area.

[0070] The correction disk 2 and the planetary mirror disk 3 are located above the annular tar polishing film 12 and are arranged circumferentially around the annular tar polishing film 12. The working surface of the correction disk 2 faces the annular tar polishing film 12, and the planetary mirror disk 3 has an area for mounting the separator 4. The separator 4 is detachably mounted on the planetary mirror disk 3. The side of the separator 4 facing the annular tar polishing film 12 has a receiving surface 41. The first surface of the ultrathin optical element 6 is connected to the receiving surface 41 by a plurality of tar adhesive portions 5 spaced apart from each other, and the second surface of the ultrathin optical element 6 faces the annular tar polishing film 12.

[0071] Polishing fluid pipe 7 is installed on base 1, with its outlet extending above the contact area between ultrathin optical element 6 and annular tar polishing film 12. During operation, correction disk 2 contacts the annular tar polishing film 12 and trims its working surface. Polishing fluid enters the contact area through polishing fluid pipe 7. Ultrathin optical element 6 moves relative to the annular tar polishing film 12 under the influence of planetary wheel mirror disk 3, achieving fine polishing of the second surface. During constant temperature settling, separator 4, along with tar bonding part 5 and ultrathin optical element 6, are removed from planetary wheel mirror disk 3, maintaining the upper plate state of ultrathin optical element 6.

[0072] In one embodiment, a first drive assembly 8 is provided on the base 1 corresponding to the planetary mirror disk 3. A first motor 81 is mounted on the base 1, and the output shaft of the first motor 81 is connected to a first drive wheel 82. The wheel surface of the first drive wheel 82 abuts against the outer peripheral surface of the planetary mirror disk 3. A first driven wheel 83 is disposed on the other side of the outer peripheral surface of the planetary mirror disk 3 and abuts against the planetary mirror disk 3 from the opposite direction to the first drive wheel 82.

[0073] When the first motor 81 drives the first driving wheel 82 to rotate, the first driving wheel 82 drives the planetary wheel mirror disk 3 to rotate around its own central axis through friction with the outer peripheral surface of the planetary wheel mirror disk 3. The first driven wheel 83 rotates with the planetary wheel mirror disk 3 and forms a rolling support for the planetary wheel mirror disk 3 from the other side.

[0074] A second drive assembly 9 is provided on the base 1 corresponding to the correction disk 2. The output end of the second motor 91 is connected to the second drive wheel 92, and the second drive wheel 92 and the second driven wheel 93 respectively abut against the outer peripheral surface of the correction disk 2. When the second drive wheel 92 rotates, it drives the correction disk 2 to rotate around its own central axis through frictional contact, and the second driven wheel 93 supports the correction disk 2 from the opposite side.

[0075] The distance between the first driving wheel 82 and the first driven wheel 83 is set according to the outer diameter of the planetary wheel mirror disk 3, and the distance between the second driving wheel 92 and the second driven wheel 93 is set according to the outer diameter of the correction disk 2, so that the corresponding driving wheels can stably transmit torque, while limiting the disk body from bearing excessive radial pressure. A wear-resistant elastic friction layer can also be provided on the outer peripheral surface of the driving wheel to improve the stability of frictional contact and buffer the small dimensional errors of the outer peripheral surface of the disk body.

[0076] When the planetary wheel mirror disk 3 and the correction disk 2 rotate respectively, the annular tar polishing film 12 passes through the trimming area where the correction disk 2 is located along with the planetary wheel mirror disk 3. After being trimmed, the tar polishing film is further transferred to the fine polishing area corresponding to the ultra-thin optical element 6, so that the trimming process of the tar polishing film and the fine polishing process of the ultra-thin optical element 6 are continuously connected.

[0077] In another embodiment, multiple separators 4 can be spaced apart on the planetary wheel mirror disk 3. Each separator 4 is detachably connected to the planetary wheel mirror disk 3 and distributed along the circumference or radial direction of the planetary wheel mirror disk 3. The receiving surface 41 of each separator 4 can be divided into multiple independent bonding areas. Each bonding area is connected to an ultra-thin optical element 6 through multiple separated tar adhesive portions 5, so that the same separator 4 can simultaneously support multiple ultra-thin optical elements 6. A gap is maintained between each ultra-thin optical element 6, and the thickness of the tar adhesive portion 5 is adjusted so that each surface to be polished is at the same working height. The number of separators 4, the number of elements supported by a single separator 4, and the spacing between adjacent elements can be adjusted according to the element size, the effective mounting area of ​​the planetary wheel mirror disk 3, and the working range of the tar polishing film, thereby adapting to ultra-thin optical elements 6 of different specifications and processing quantities.

[0078] In another embodiment, the polishing disc 11 is rotatably mounted on the base 1 via a central rotating shaft and bearing assembly, and rotates around its own central axis. The annular tar polishing film 12 rotates synchronously with the polishing disc 11. The driving component of the polishing disc 11 can be located inside or below the base 1, and connected to the central rotating shaft via a coupling, gear, belt drive, or other transmission structure. To simplify the drawings and highlight the working positional relationship between the polishing disc 11, the correction disc 2, and the planetary mirror disc 3, the driving component of the polishing disc 11 is omitted in the drawings, but it can be any feasible rotary drive scheme in the prior art. During processing, the rotation of the polishing disc 11 drives the annular tar polishing film 12 to move continuously, so that the tar polishing film passes through the areas where the correction disc 2 and the ultra-thin optical element 6 are located, and together with the rotation of the correction disc 2 and the ultra-thin optical element 6, forms the relative motion required for fine polishing.

[0079] The above description is only a preferred embodiment of this application and does not limit the patent scope of this application. Any equivalent structural or procedural changes made based on the content of this application's specification and drawings, or direct or indirect applications in other related technical fields, are similarly included within the patent protection scope of this application.

Claims

1. A polishing process for ultra-thin optical components, characterized in that, include: S1. The first surface of the ultra-thin optical element is bonded to the receiving surface of the separator through multiple asphalt bonding parts that are separated from each other, and the second surface is away from the separator to obtain the upper plate. S2. Add polishing liquid between the second surface and the prepared tar polishing film, and then apply the tar polishing film to the second surface for fine polishing to obtain a staged polished part. S3. Remove the staged polished parts from the asphalt polishing film and allow them to stand at a constant temperature. Then, attach the staged polished parts back onto the asphalt polishing film after standing. Alternately perform single fine polishing and constant temperature standing to obtain finely polished parts. S4. Perform low-temperature cooling and low-temperature cleaning on the polished part, and place the ultra-thin optical element separated from the separator in a constant temperature environment.

2. The ultra-thin optical element polishing process according to claim 1, characterized in that, Prior to the step of bonding the first surface of the ultrathin optical element to the receiving surface of the separator via multiple spaced-apart tar adhesive portions, the method further includes: The ultra-thin optical element is placed between two oppositely arranged coarse polishing surfaces, and coarse polishing liquid is added between the two surfaces and the corresponding coarse polishing surfaces. Simultaneous rough polishing of the two surfaces removes the damaging layer formed on the two surfaces during the fine grinding process; Clean the two surfaces after rough polishing, and then place the cleaned ultrathin optical components horizontally.

3. The ultra-thin optical element polishing process according to claim 1, characterized in that, The step of bonding the first surface of the ultrathin optical element to the receiving surface of the separator through multiple tar adhesive portions spaced apart from each other includes: A bonding area corresponding to the outline of the ultra-thin optical element is defined on the receiving surface of the separator, and multiple equal amounts of asphalt are arranged at intervals within the bonding area. Soften and flatten multiple asphalt blocks so that the end faces of each asphalt block facing the first surface are on the same supporting plane; The first surface is pressed onto multiple asphalt materials and cooled to set, forming an asphalt bonding part that connects the first surface and the separator and is separated from each other.

4. The ultra-thin optical element polishing process according to claim 3, characterized in that, After the step of obtaining the upper disk component, the method further includes: Align the separator of the upper disc with the mounting position of the planetary wheel mirror disc, and make the second surface face the tar polishing film; The separator is placed into the planetary wheel mirror disk along the axial direction, so that the outer edge of the separator is circumferentially positioned with the planetary wheel mirror disk. Adjust the position of the upper plate in the planetary wheel mirror disk so that the second surface corresponds to the working area of ​​the tar polishing film, and obtain the lens assembly to be finely polished.

5. The ultra-thin optical element polishing process according to claim 1, characterized in that, The steps for forming the modified tar polished film include: A tar polishing film is laid on the working surface of the polishing disc, and the working surface of the correction disc is pressed onto the tar polishing film. Rotate the correction disc so that its working surface slides along the surface of the asphalt polishing film; The surface shape of the tar polishing film is adjusted to obtain the adjusted tar polishing film.

6. The ultra-thin optical element polishing process according to claim 1, characterized in that, The step of applying a tar polishing film to the second surface for fine polishing includes: Polishing liquid is dripped onto the contact area between the second surface and the asphalt polishing film, and the second surface is pressed onto the asphalt polishing film; Drive the upper disk to rotate, so that the second surface slides along the surface of the asphalt polishing film; Maintain the polishing slurry to cover the contact area to complete a single fine polishing, resulting in a staged polished part.

7. The ultra-thin optical element polishing process according to claim 4, characterized in that, The step of removing the staged polished part from the tar polishing film and allowing it to stand at a constant temperature includes: The separator, along with the ultra-thin optical elements, is removed from the planetary wheel mirror disk, causing the second surface to detach from the tar polishing film. Maintain the tar bond between the ultra-thin optical components and the separator, and place the upper plate horizontally in a constant temperature environment. After the separator has settled, it is reinstalled on the planetary wheel mirror disk so that the second surface faces the asphalt polishing film again.

8. The ultra-thin optical element polishing process according to claim 1, characterized in that, The steps of performing low-temperature lowering and low-temperature cleaning on the polished parts, and placing the ultra-thin optical components separated from the separator in a constant-temperature environment include: The asphalt bond between the first surface and the separator is softened under low temperature conditions, and the bond between the first surface and the separator is released. The residual tar on the first surface is removed using a low-temperature cleaning solution; The cleaned ultrathin optical components are placed in a constant temperature environment and left to stand.

9. A polishing device for ultra-thin optical components, characterized in that, Includes a base (1), and a polishing disc (11) is rotatably disposed in the middle of the base (1), and an annular tar polishing film (12) is laid on the upper surface of the polishing disc (11). The base (1) is provided with a correction disk (2) and a planetary wheel mirror disk (3). The correction disk (2) and the planetary wheel mirror disk (3) are located above the annular tar polishing film (12) and are distributed at intervals along the circumference of the annular tar polishing film (12). A separator (4) is detachably provided inside the planetary wheel mirror disk (3). The separator (4) has a receiving surface (41) facing the annular tar polishing film (12). The ultra-thin optical element (6) is connected to the receiving surface (41) through a plurality of tar adhesive parts (5) separated from each other. The surface of the ultra-thin optical element (6) facing away from the separator (4) faces the annular tar polishing film (12). The base (1) is provided with a polishing fluid pipe (7), and the outlet end of the polishing fluid pipe (7) is directed toward the contact area between the ultra-thin optical element (6) and the annular asphalt polishing film (12).

10. The ultra-thin optical element polishing equipment according to claim 9, characterized in that, The base (1) is provided with a first drive assembly (8) and a second drive assembly (9) respectively corresponding to the planetary wheel mirror disk (3) and the correction disk (2). The first drive assembly (8) includes a first motor (81), a first drive wheel (82) and a first driven wheel (83). The first drive wheel (82) is connected to the output end of the first motor (81), and the first drive wheel (82) and the first driven wheel (83) respectively abut against the outer peripheral surface of the planetary gear mirror disk (3). The second drive assembly (9) includes a second motor (91), a second drive wheel (92), and a second driven wheel (93). The second drive wheel (92) is connected to the output end of the second motor (91), and the second drive wheel (92) and the second driven wheel (93) respectively abut against the outer peripheral surface of the correction disc (2).

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