Polishing head for aspheric workpiece

By designing an aspherical polishing head with a conical swivel structure and polishing cloth covering, the problem of easy stripe marks on the surface of aspherical workpieces after polishing in the prior art is solved, and better surface type error control and imaging quality improvement are achieved.

CN222971778UActive Publication Date: 2025-06-13LEADING OPTICS (SHANGHAI) CO LTD
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Patent Information

Application Number
CN202421858721.1
Authority / Receiving Office
CN · China
Patent Type
Utility models(China)
Current Assignee / Owner
Filing Date
2024-08-01
Publication Date
2025-06-13
Estimated Expiration
2034-08-01

AI Technical Summary

Technical Problem

When the existing spherical polishing head polishes aspherical workpieces, it is easy to cause striped marks on the surface of the workpiece, making it difficult to achieve ideal surface type errors, and affects the imaging quality of the lens.

Method used

A polishing head for aspherical workpiece is designed, the polishing end is a swivel structure, the outer contour surface type is a conical surface formed by an arc about the central rotation axis, the curvature radius of the arc is the best fit radius of the aspherical surface type of the optical element to be polished, and the polishing cloth is coated outside the polishing end to form a linear contact state.

Benefits of technology

Through this design, the polishing head and the surface of the aspherical workpiece are as linear as possible, avoiding the formation of stripes, making the polished surface more neat and uniform, and reducing the surface surface pattern error of the workpiece.

✦ Generated by Eureka AI based on patent content.

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Abstract

The utility model relates to the field of surface polishing, in particular to a polishing head for an aspheric workpiece. Comprising a polishing end part and polishing cloth, the outer contour surface of the polishing end part is a conical surface formed by an arc line around a central rotating shaft, and the curvature radius corresponding to the arc line is the optimal fitting radius of the aspheric surface type of the optical element to be polished; and the outer contour of the polishing end part is coated with the polishing cloth. The polishing end part is the conical rotary body formed by the arc line corresponding to the surface type optimal fitting radius of the aspheric surface to be polished, so that in the polishing process, the outer contour of the polishing end part has a joint of a surface with a certain length and the surface of the aspheric surface workpiece, and the surface of the aspheric surface workpiece is not damaged in the polishing process. And the polishing head is in linear contact with the aspheric workpiece surface as far as possible. By means of the technical scheme, stripe traces formed on the polished surface of the workpiece can be avoided, the polished surface is neater and more uniform, the surface type error of the surface of the workpiece is reduced, and the surface quality of an optical element is improved.
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Description

Technical Field

[0001] The utility model relates to the field of surface polishing, in particular to a polishing head for aspherical workpieces. Background Art

[0002] Aspherical polishing is a technology for manufacturing high-quality optical lenses, especially for reducing spherical aberration and coma aberration, thereby improving the imaging quality and visual clarity of the lenses. Due to the limitation of the curved surface shape of traditional spherical lenses, the light rays often do not focus on the same plane, resulting in blurred and distorted images. Aspherical lenses, on the other hand, have a more complex curved surface through special design and processing of the lens surface, enabling better optical performance within a wider field of view. Moreover, aspherical lenses are usually thinner and lighter than spherical lenses, making them more suitable for making lightweight glasses.

[0003] During the preparation of aspherical lenses, polishing is an important step to remove the minor unevenness on the lens surface, so that the processed surface shape fits the designed surface shape more closely, thereby improving the imaging effect. However, in the existing polishing technologies, when a spherical polishing head is usually used for polishing, it has a point contact with the surface of the aspherical workpiece, which will result in obvious stripe marks on the polished surface of the workpiece, as Figure 3 shown, making it difficult for the surface shape error of the workpiece surface to reach the ideal level and causing the imaging quality of the lens to deteriorate. Summary of the Invention

[0004] In view of this, the utility model provides a polishing head for aspherical workpieces, which at least partially solves the problems existing in the prior art.

[0005] According to one aspect of the utility model, there is provided a polishing head for aspherical workpieces, comprising:

[0006] A polishing end and a polishing cloth;

[0007] The polishing end is of a rotary body structure, and the outer contour surface shape of the polishing end is a conical surface formed by an arc rotating around the central axis of rotation. The radius of curvature corresponding to the arc is the best fitting radius of the aspherical surface shape of the optical element to be polished;

[0008] The polishing cloth is coated on the outer contour surface of the polishing end.

[0009] Furthermore, the polishing end is inclined, and the inclination angle is the angle formed when the point within [3 / 5, 4 / 5] of the arc length forming the polishing end is the lowest point in the vertical direction when the tool setting is completed.

[0010] Further, the inclination angle is formed when the lowest point in the vertical direction is at the point that is 2 / 3 of the arc length forming the polished end when the tool setting is completed.

[0011] Further, the workpiece rotating spindle has a normal tracking ability, and the polished end is inclined at a preset working angle.

[0012] Further, it further includes:

[0013] A connecting part and a clamping part;

[0014] The connecting part is connected between the non-tip side of the polished end and the clamping part;

[0015] Both the connecting part and the clamping part are cylindrical rod-shaped structures, and the diameter of the connecting part is larger than that of the clamping part.

[0016] Further, the polishing cloth includes a lint-free cloth, a wool felt, or a damping cloth.

[0017] Further, the polished end, the connecting part, and the clamping part are integrally formed.

[0018] Further, the polished end, the connecting part, and the clamping part are all made of stainless steel or 45# steel.

[0019] Further, the convex side of the arc is arranged away from the central rotation axis, so that the outer contour surface shape of the polished end is a convex surface.

[0020] Further, the convex side of the arc is arranged close to the central rotation axis, so that the outer contour surface shape of the polished end is a concave surface.

[0021] The technical solution of the present utility model has at least the following beneficial effects:

[0022] In the present utility model, the polished end is a conical rotating body formed by an arc corresponding to the best fitting radius of the aspherical surface to be polished. Therefore, during the polishing process, there will be a certain length of surface of the outer contour of the polished end in contact with the surface of the aspherical workpiece, so that during the polishing process, the contact between the polishing head and the surface of the aspherical workpiece is preferably a line contact. In addition, in order to further form a line contact state, a polishing cloth is also wrapped outside the polished end. Therefore, under the flexible contact of the polishing cloth, it is easier to form a line contact state between the polishing head and the surface of the aspherical workpiece. Correspondingly, polishing under this contact state can avoid forming stripe marks on the surface of the workpiece after polishing, thereby making the polished surface more neat and uniform, and further reducing the surface shape error of the workpiece. Description of the Drawings

[0023] To more clearly illustrate the technical solutions of the embodiments of the present utility model, the following will briefly introduce the drawings required for use in the embodiments. Obviously, the drawings in the following description are only some embodiments of the present utility model. For those of ordinary skill in the art, without creative efforts, other drawings can be obtained based on these drawings.

[0024] Figure 1 Schematic diagram of the structure of the polishing head used for the convex aspherical workpiece surface profile in an embodiment of the present application;

[0025] Figure 2 Schematic diagram of the structure of the polishing head used for the concave aspherical workpiece surface profile in another embodiment of the present application;

[0026] Figure 3 Microstructure image of the workpiece surface profile after polishing with the existing spherical polishing head in the background technology;

[0027] Figure 4 Microstructure image of the workpiece surface profile after polishing with the polishing head of the present application;

[0028] Figure 5 In another embodiment of the present application, when the intersection point of the rotation axis of the workpiece rotation spindle and the formed polishing end is at a position closer to the tip of the polishing end (i.e., in the region of 0 - 1 / 5), the surface profile machining error of the workpiece surface (in the interval of -0.1 to 0.2 μm);

[0029] Figure 6 In another embodiment of the present application, when the intersection point of the rotation axis of the workpiece rotation spindle and the formed polishing end is in a position region closer to the tail of the polishing end (i.e., in the region of 9 / 10 - 1), the surface profile machining error of the workpiece surface (in the interval of -0.1 to 0.25 μm);

[0030] Figure 7 In another embodiment of the present application, when the point at 2 / 3 of the arc length forming the polishing end is the lowest point in the vertical direction, the surface profile machining error of the workpiece surface (in the interval of -0.07 to 0.06 μm);

[0031] Figure 8 Schematic diagram of the working state of the polishing head during polishing in an embodiment of the application.

[0032] Reference numerals

[0033] 1. Polishing end; 2. Connecting part; 3. Clamping part; 4. Polishing cloth; 5. Workpiece to be polished; 6. Workpiece rotation spindle. Detailed implementation manners

[0034] The following will describe the embodiments of the present utility model in detail with reference to the drawings.

[0035] It should be noted that, without conflict, the following embodiments and the features in the embodiments may be combined with each other; and, based on the embodiments in the present disclosure, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the scope of protection of the present disclosure.

[0036] It should be noted that the following describes various aspects of embodiments within the scope of the appended claims. It should be apparent that the aspects described herein can be embodied in a wide variety of forms, and any specific structure and / or function described herein is illustrative only. Based on the present disclosure, those skilled in the art should understand that one aspect described herein can be implemented independently of any other aspect, and two or more of these aspects can be combined in various ways. For example, any number of the aspects described herein can be used to implement a device and / or practice a method. Additionally, this device and / or method can be implemented using other structures and / or functions in addition to one or more of the aspects described herein.

[0037] As an embodiment of the present utility model, as Figures 1 to 8 shown, a polishing head for use with an aspherical workpiece is provided, including: a polishing end portion 1, a polishing cloth 4, a connecting portion 2, and a clamping portion 3.

[0038] The polishing end portion 1 is of a rotary body structure, and the outer contour surface type of the polishing end portion 1 is a conical surface formed by an arc rotating around a central rotation axis. The curvature radius corresponding to the arc is the best fit radius of the aspherical surface type of the optical element to be polished. The arc in this embodiment is equivalent to the generatrix of the conical rotary body.

[0039] The best fit sphere radius (BFSR) of an aspherical surface refers to the radius value of a sphere when the surface of an aspherical lens or lens can be approximately represented by a sphere. Simply put, the best fit radius is the radius of the sphere that is closest to the aspherical surface.

[0040] In addition, since the aspherical surface type to be polished has a convex surface or a concave surface, the outer contour surface type of the corresponding formed polishing end portion 1 should be a concave surface or a convex surface. Therefore, when setting the generatrix (i.e., the above-mentioned arc), its placement state can be set in the following two forms:

[0041] The convex side of the arc is set away from the central rotation axis side, so that the outer contour surface type of the polishing end portion 1 is a convex surface.

[0042] Or, the convex side of the arc is set closer to the central rotation axis side, so that the outer contour surface type of the polishing end portion 1 is a concave surface.

[0043] The connecting part 2 is connected between the non-tip side of the polishing end 1 and the clamping part 3. Both the connecting part 2 and the clamping part 3 are cylindrical rod-shaped structures, and the diameter of the connecting part 2 is larger than that of the clamping part 3. Through the change in diameter, a concave stepped surface can be formed at the connection of the connecting part 2 and the clamping part 3, and this stepped surface facilitates tying and fixing the end of the polishing cloth 4 wrapped around the polishing end 1 with a cord.

[0044] Specifically, the polishing end 1, the connecting part 2, and the clamping part 3 are integrally formed. The polishing end 1, the connecting part 2, and the clamping part 3 are all made of stainless steel or 45# steel. The material of the polishing end 1 is preferably stainless steel because polishing liquid is used during the polishing process, and stainless steel can reduce the risk of the polishing head being corroded.

[0045] Figure 8 The polishing cloth 4 is wrapped around the outer contour surface of the polishing end 1. Specifically, the polishing cloth 4 can be a lint-free cloth, a wool felt, or a damping cloth.

[0046] Thus, under the flexible contact of the polishing cloth 4, it is easier to form a line contact state between the polishing head and the aspherical workpiece surface. Correspondingly, polishing under this contact state can avoid forming stripe marks on the polished surface of the workpiece, and further make the polished surface more neat and uniform, as Figure 4 shown, thereby reducing the surface profile error of the workpiece.

[0047] As another embodiment of the present invention, in this embodiment, the workpiece rotating spindle 6 has the ability of normal tracking, and the polishing end 1 is inclined at a preset working angle. As Figure 8 shown, in actual polishing processing, the workpiece to be polished 5 is fixed on the workpiece rotating spindle 6 and rotates with the spindle. And the workpiece rotating spindle 6 has the ability of normal tracking. In the polishing process, the so-called "rotating spindle has the ability of normal tracking" usually means that the rotating spindle of the polishing equipment can adjust the placement angle of the workpiece in real time according to the curvature change of the processed surface to ensure that the polishing tool is always perpendicular to the processed surface. This ability is particularly important for processing aspherical lenses because the surface curvature of aspherical lenses is non-uniform, and it is difficult for traditional polishing methods to ensure the best contact state throughout the processing. In this embodiment, the polishing end 1 is always inclined at a preset working angle, and polishing is carried out through the normal tracking of the rotating spindle.

[0048] Furthermore, the polishing end 1 is inclined, and the inclination angle is the angle formed when the lowest point in the vertical direction is the point within [3 / 5, 4 / 5] of the arc length forming the polishing end 1 when the tool setting is completed.

[0049] Generally, in this embodiment, the size of the inclination angle of the polishing end 1 is determined by the intersection position of the rotation axis of the workpiece rotation spindle 6 when it is vertically upward and the arc forming the polishing end 1. Generally, during tool setting, the workpiece rotation spindle 6 will return to the preset position and state. In this embodiment, it can be the state where the workpiece rotation spindle 6 is at the corresponding position and the rotation axis is vertically upward, and at this time, the rotation axis will intersect with the lowest point of the polishing end 1 in the vertical direction. Thus, in this embodiment, the inclination angle of the polishing end 1 is adjusted so that the rotation axis of the workpiece rotation spindle 6 intersects with a point within [3 / 5, 4 / 5] of the arc length forming the polishing end 1, thereby forming a corresponding inclination angle. Take this angle as the working angle of the polishing end 1 during the polishing process. In the above inclination state, the surface of the workpiece has a better polishing effect, and the overall surface shape error can be controlled within a smaller range.

[0050] However, if the arc length is set to 1, then when the intersection point is in a position closer to the tip of the polishing end 1 (i.e., in the area of 0 - 1 / 5) or in a position area closer to the tail of the polishing end 1 (i.e., in the area of 9 / 10 - 1), the surface shape error will suddenly increase at different positions of the workpiece.

[0051] Specifically, when the intersection point is in the interval of [0, 1 / 5], as Figure 5 shown, the surface shape errors at the center of the workpiece and the positions near the edge are relatively large. When the intersection point is in the interval of [9 / 10, 1], as Figure 6 shown, the surface shape error at the center position of the workpiece is relatively large.

[0052] Preferably, the inclination angle is the angle formed when the lowest point in the vertical direction is the point at 2 / 3 of the arc length forming the polishing end 1 when the tool setting is completed. In this state, as Figure 7 shown, the overall surface shape error of the workpiece is reduced, and it differs by nearly an order of magnitude compared with the above error range, and the errors of each part of the workpiece are relatively uniform, and the control effect of the surface shape error is better.

[0053] The above is only the specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any changes or substitutions that can be easily thought of by those skilled in the art within the technical scope disclosed by the present invention should be covered within the protection scope of the present invention. Therefore, the protection scope of the present invention should be subject to the protection scope of the claims.

Claims

1. A polishing head for a non-spherical workpiece, characterized in that: include: Polishing tip and polishing cloth; The polishing end is a body of revolution structure, the outer contour of the polishing end is a conical surface formed by an arc around a central rotation axis, and the curvature radius corresponding to the arc is the best fitting radius of the aspheric surface of the optical element to be polished; The polishing cloth is coated on the outer contour surface of the polishing end portion.

2. The polishing head for a non-spherical workpiece according to claim 1, characterized in that: The polishing end is tilted, and the tilt angle is the angle formed when the point within [3 / 5, 4 / 5] of the arc length of the polishing end is the lowest point in the vertical direction when the tool setting is completed.

3. The polishing head for a non-spherical workpiece according to claim 2, characterized in that: The inclination angle is the angle formed when the point at 2 / 3 of the arc length of the polishing end is the lowest point in the vertical direction when the tool setting is completed.

4. The polishing head for a non-spherical workpiece according to claim 3, characterized in that: The workpiece rotating spindle has a normal tracking capability, and the polishing end is tilted at a preset working angle.

5. The polishing head for a non-spherical workpiece according to claim 1, characterized in that: Also includes: Connecting part and clamping part; The connecting portion is connected between the non-tip side of the polishing end portion and the clamping portion; The connecting portion and the clamping portion are both cylindrical rod-shaped structures, and the diameter of the connecting portion is greater than the diameter of the clamping portion.

6. The polishing head for a non-spherical workpiece according to claim 1, characterized in that: The polishing cloth includes a dust-free cloth, a wool felt or a damping cloth.

7. The polishing head for a non-spherical workpiece according to claim 1, characterized in that: The polishing end, the connecting portion and the clamping portion are integrally formed.

8. The polishing head for a non-spherical workpiece according to claim 1, characterized in that: The polished end, the connecting part and the clamping part are all made of stainless steel or No. 45 steel.

9. The polishing head for a non-spherical workpiece according to claim 1, characterized in that: The convex side of the arc is arranged away from the central rotation axis so that the outer contour surface of the polishing end is a convex surface.

10. The polishing head for a non-spherical workpiece according to claim 1, characterized in that: The convex side of the arc is arranged close to the central rotation axis so that the outer contour surface of the polishing end is a concave surface.