High-reproducibility optical device low-frequency surface shape detection supporting device

Abstract

The invention belongs to the field of surface shape detection of optical devices, and discloses a high-reproducibility optical device low-frequency surface shape detection supporting device, which comprises a supporting bottom plate, three groups of bearing roller assemblies mounted on the supporting bottom plate and three dome structures uniformly distributed and bonded on the optical device at 120 degrees, and three flexible elastic sheet structures are uniformly distributed on the supporting bottom plate at 120 degrees. The bearing roller assembly is installed at the flexible elastic sheet structure and is used for releasing the radial force in the detection process. Each bearing roller assembly comprises four angular contact bearings, four bearing pressing rings, two rollers, two first rotating shafts, two second rotating shafts and a bearing seat; and the surfaces of the roller of the bearing roller assembly and the rolling ball of the ball top structure are plated with wear-resistant and anti-attrition coatings. According to the supporting device, a bearing and roller structure is adopted to replace a traditional V-groove structure, and an elastic piece structure is added to release radial force and reduce friction force, so that the influence on the surface shape is reduced, and the reproducibility of surface shape detection is greatly improved.

Description

Technical Field

[0001] This invention belongs to the field of optical device surface shape detection technology, specifically relating to a low-frequency surface shape detection support device for high-reproducibility optical devices, which is suitable for high-end optical detection scenarios where the surface shape accuracy of optical devices is required to reach the sub-nanometer level. Background Technology

[0002] With the continuous improvement of imaging quality requirements for optical systems, especially the evolution of working wavelengths in the lithography field towards the 6-7 nm band, the surface processing and inspection accuracy of optical devices has entered the sub-nm level, which puts forward stringent requirements on the consistency and reproducibility of inspection results.

[0003] In the processing of optical devices (such as lenses, mirrors, etc.), it is necessary to repeatedly perform the iterative process of "low-frequency surface shape detection-reprocessing-re-detection". Optical devices need to be repeatedly loaded and unloaded. Due to the difference in the direction and angle of each loading and unloading, the magnitude and direction of friction force are different, which in turn causes the lens to be subjected to different forces, affecting the consistency of surface shape detection for each loading and unloading, and resulting in poor surface shape detection reproducibility.

[0004] While the commonly used 3-ball 3V-groove kinematic support device can achieve the support effect of six degrees of freedom in space, there is a large friction between the support device and the optical components. Moreover, the difference in the direction and angle of each sample loading and unloading will cause the magnitude and direction of the friction to be unstable, resulting in uneven stress on the optical components and seriously affecting the consistency of the detection results. The existing support structure that directly uses bearings to replace V-grooves has problems such as the difficulty in eliminating bearing clearance, insufficient hardness and wear resistance of bearing materials, and inconvenience in coating wear-resistant and friction-reducing coatings. Its long-term stability is poor and it cannot meet the requirements of high-precision low-frequency surface shape detection reproducibility, making it difficult to converge to the ideal surface shape during processing. Summary of the Invention

[0005] The purpose of this invention is to address the problems of poor reproducibility, significant influence of friction, and insufficient long-term stability of existing low-frequency surface shape detection support devices for optical devices, and to provide a high-reproducibility low-frequency surface shape detection support device for optical devices. This device significantly improves the surface shape reproducibility during repeated sample loading and unloading detection of optical devices, resulting in an RMS value better than 0.1 nm for the reproducibility detection results, while also enhancing the device's environmental adaptability and long-term stability.

[0006] To achieve the above objectives, the present invention adopts the following technical solution:

[0007] A support device for low-frequency surface shape detection of high reproducibility optical devices includes a support base plate, three sets of bearing roller assemblies and three dome structures; three flexible spring sheet structures are evenly distributed along the circumference of 120° on the support base plate, the bearing roller assemblies and the flexible spring sheet structures are fixedly connected one-to-one, and the dome structures are evenly distributed along the circumference of 120° on the optical devices.

[0008] The bearing roller assembly includes a bearing housing, a roller, an angular contact bearing, a bearing retaining ring, and a rotating shaft. Two angular contact bearings support one roller to form a rolling contact point. The angular contact bearings are preloaded by the bearing retaining ring to eliminate their own clearance. The dome structure forms a rolling adaptation contact with the bearing roller assembly. The three sets of bearing roller assemblies provide a total of six support points to constrain the six degrees of freedom of the optical device in space.

[0009] The bearing roller assembly, flexible spring structure, and dome structure of the present invention are all evenly distributed along the circumference at 120°, forming a symmetrical and stable three-point support layout. This layout can accurately constrain the six degrees of freedom of the optical device through six sets of rolling contact points, ensure uniform force distribution during the detection process, avoid local stress concentration affecting the surface shape detection accuracy, simplify assembly and positioning operations, and improve the practicality and adaptability of the device.

[0010] As a further description of the above technical solution: the roller is made of hard ceramic material or stainless steel material to enhance surface hardness and wear resistance, further reduce friction loss during rolling contact, and improve the long-term stability of the device.

[0011] As a further description of the above technical solution: the surface of the roller is coated with a wear-resistant and friction-reducing coating, which effectively improves the wear resistance and lubrication characteristics of the roller surface, reduces the fluctuation of the friction coefficient when rolling in contact with the dome structure, and further ensures the stability of the force during the detection process.

[0012] As a further description of the above technical solution: the rotating shaft includes a first rotating shaft and a second rotating shaft. The first rotating shaft and the second rotating shaft are respectively inserted into the mounting holes on both sides of the bearing housing to form an interference or transition fit with the inner ring of the angular contact bearing, thereby realizing the precise positioning of the angular contact bearing in the bearing housing. This simplifies the bearing assembly operation and ensures the coaxiality of the bearing after installation, thereby improving the smoothness of the roller rolling.

[0013] As a further description of the above technical solution: the dome structure includes a dome body and a rolling sphere. The dome body has a hemispherical cavity adapted to the rolling sphere. The opening end of the hemispherical cavity has a closing structure. The rolling sphere is embedded in the hemispherical cavity to form a rolling fit structure. The closing structure provides reliable radial restraint for the rolling sphere, so that the rolling sphere can only rotate freely within the cavity without falling off.

[0014] As a further description of the above technical solution: the dome body is bonded and fixed to the optical device with epoxy adhesive to form an integrated assembly structure. During the bonding process, the thickness of the adhesive layer is controlled to be uniform and there are no air bubbles. After curing, the dome body and the optical device form a stable and uniformly stressed integrated assembly structure, which avoids displacement deviation caused by loose bonding during the testing process, and at the same time reduces the influence of bonding stress on the surface shape of the optical device.

[0015] As a further description of the above technical solution: the rolling ball is made of hard ceramic material or stainless steel material, which not only ensures that it has high hardness and deformation resistance, but also forms an optimized friction pair with the wear-resistant and friction-reducing coating on the surface of the roller, further reducing friction loss and friction coefficient fluctuation during rolling contact, extending the service life of the component and ensuring the stability of detection reproducibility.

[0016] As a further description of the above technical solution: the surface of the rolling ball is coated with a wear-resistant and friction-reducing coating, which works synergistically with the wear-resistant and friction-reducing coating on the surface of the roller. This can significantly reduce the coefficient of friction during the rolling contact process, reduce wear and loss of the contact surface, and further improve the smoothness and force consistency of the rolling contact, providing a double guarantee for the stability of the detection reproducibility.

[0017] Compared with the prior art, the present invention has the following beneficial effects:

[0018] The detection support device of this invention releases the radial force during the detection process through the evenly distributed flexible spring sheet structure on the support base plate. In conjunction with the angular contact bearing in the bearing roller assembly, the clearance is eliminated by the pressure ring pre-tightening, and the rolling adaptation contact formed between the bearing roller assembly and the dome structure, which not only stably constrains the six degrees of freedom of the optical device in space with six support points, but also significantly reduces the friction fluctuations during sample loading, unloading and detection, effectively improving the reproducibility of low-frequency surface shape detection of optical devices, making the RMS value of the detection result better than 0.1 nm. At the same time, the device is easy to assemble and operate, and the wear-resistant structure design of the roller and dome also enhances the long-term stability. It can be adapted to sub-nm high-precision optical detection scenarios such as photolithography, and has strong environmental adaptability. Attached Figure Description

[0019] Figure 1 This is a side view of the assembly of the low-frequency surface shape detection support device for the high reproducibility optical device of the present invention with the optical device.

[0020] Figure 2 This is a side view of the low-frequency surface shape detection support device for the high reproducibility optical device of the present invention.

[0021] Figure 3 This is a top view of the support base plate in the low-frequency surface shape detection support device for high reproducibility optical devices of the present invention.

[0022] Figure 4This is a side view of the bearing roller assembly in the low-frequency surface shape detection support device for high-reproducibility optical devices of the present invention.

[0023] Figure 5 This is a cross-sectional view of the bearing roller assembly in the low-frequency surface shape detection support device for high-reproducibility optical devices of the present invention.

[0024] Figure 6 This is a side view of the dome structure in the low-frequency surface shape detection support device for high-reproducibility optical devices of the present invention.

[0025] Figure label:

[0026] 1-Optical components, 2-Dome structure, 21-Dome body, 22-Rolling sphere, 3-Supporting base plate, 4-Flexible spring structure, 5-Bearing roller assembly, 51-Bearing seat, 52-Roller, 53-Angular contact bearing, 54-Bearing pressure ring, 55-First rotating shaft, 56-Second rotating shaft. Detailed Implementation

[0027] The claims of the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments, but this does not constitute any limitation on the present invention. Any limited modifications made by any person within the scope of protection of the claims of the present invention shall still be within the scope of protection of the claims of the present invention.

[0028] Support device for low-frequency surface shape detection of high-reproducibility optical devices, such as Figures 1 to 6 As shown, it includes a supporting base plate 3, three sets of bearing roller assemblies 5, and three dome structures 2;

[0029] The support base plate 3, as the basic load-bearing component of the device, is made of high-strength, high-rigidity alloy material. Three flexible spring sheet structures 4 are evenly distributed at 120° on it. The uniformity of the three flexible spring sheet structures 4 is ensured by precision machining. The thickness and elastic coefficient of the spring sheet are designed according to the weight and radial force requirements of the optical device 1 to ensure that the radial force generated during the detection process can be effectively released without excessive deformation, thereby reducing the impact of the radial force on the surface shape of the optical device.

[0030] Three sets of bearing roller assemblies 5 are fixed one-to-one with each other at the flexible spring structure 4 of the supporting base plate 3. Each set of bearing roller assemblies 5 includes a bearing housing 51, two rollers 52, four angular contact bearings 53, four bearing retaining rings 54, two first rotating shafts 55, and two second rotating shafts 56. The four angular contact bearings 53 are respectively sleeved on one end of the first rotating shaft 55 and the second rotating shaft 56. The first rotating shafts 55 and the second rotating shafts 56 are respectively inserted into the mounting holes on both sides of the bearing housing 51, so that the angular contact... An angular contact bearing 53 is embedded in the mounting hole of the bearing housing 51; a roller 52 is sleeved on the outer side of the mating end of the first rotating shaft 55 and the second rotating shaft 56. The two angular contact bearings 53 together support a roller 52 to form a rolling contact point, and the two sides of the roller 52 respectively abut against the outer ring of the corresponding angular contact bearing 53; the bearing retainer 54 is threadedly connected to the mounting hole of the bearing housing 51, and after tightening, it abuts against the end face of the inner ring of the angular contact bearing 53 to achieve pre-tightening of the angular contact bearing 53 and eliminate the bearing's own clearance. The bearing housing 51 is made of aerospace-grade aluminum alloy to ensure installation accuracy; the angular contact bearing 53 is selected as a high-precision product, and the clearance is completely eliminated by pre-tightening adjustment through the bearing retainer 54; the roller 52 is made of hard ceramic material (or stainless steel material), and after precision grinding, it is coated with a wear-resistant and friction-reducing coating; the first rotating shaft 55 and the second rotating shaft 56 are made of stainless steel material, and the surface is treated with rust prevention to ensure the fitting accuracy with the inner ring of the bearing.

[0031] The dome structure 2 includes a dome body 21 and a rolling sphere 22. The dome body 21 has a hemispherical cavity adapted to the rolling sphere 22. The opening end of the hemispherical cavity has a constriction structure, the inner diameter of which is slightly smaller than the diameter of the rolling sphere 22. The rolling sphere 22 is embedded in the hemispherical cavity to form a rolling fit structure. The constriction structure radially limits the rolling sphere 22, allowing it to rotate freely within the cavity without falling off. The dome body 21 is made of hard alloy material and is bonded to the optical device 1 (reflector) at a predetermined position using optical-grade low-stress epoxy adhesive. After bonding, it undergoes curing treatment to ensure a strong integrated component with the optical device 1, and the bonding stress does not affect the surface shape of the optical device. The rolling sphere 22 is made of hard ceramic material (or stainless steel material) and its surface is coated with a wear-resistant and friction-reducing coating that matches the roller 52, reducing the coefficient of friction during rolling contact and minimizing wear on the contact surface.

[0032] Each bearing roller assembly 5 forms two support points with the corresponding dome structure 2, constraining the axial and tangential translational motion of the optical device 1. The three evenly distributed bearing roller assemblies 5 provide a total of six support points, precisely constraining the six degrees of freedom of the optical device 1 in space, ensuring support stability. The flexible spring structure 4 on the support base plate 3 can also absorb radial force through free deformation. Combined with the rolling characteristics of the rollers 52, it significantly reduces tangential, radial, and axial friction, avoiding detection deviations caused by friction fluctuations and improving reproducibility.

[0033] During assembly, the angular contact bearings 53 are first installed from both ends of the bearing housing 51 via the first rotating shaft 55 and the second rotating shaft 56. Each roller 52 is equipped with two angular contact bearings 53. After installation, the bearing pressure rings 54 are used for pre-tightening to ensure that the bearing clearance is eliminated, thus completing the assembly of the bearing roller assembly 5. The three sets of assembled bearing roller assemblies 5 are then fixed to three flexible spring structures 4 on the support base plate 3 and secured with bolts to ensure that the three sets of bearing roller assemblies 5 are evenly distributed at 120° around the support base plate 3 and that the top surfaces of the rollers 52 are at the same horizontal height. Then, the three dome structures 2 are bonded to the optical device 1 (such as a reflector) with epoxy adhesive according to the 120° even distribution requirement. After curing, the accuracy is checked to ensure that the position deviation of the dome does not exceed ±0.01 mm. Finally, the optical device 1 with the dome structure 2 bonded to it is placed on the three sets of bearing roller assemblies 5, so that the rolling ball 22 of each dome structure 2 forms two stable contact points with the corresponding roller 52, thus completing the overall assembly.

[0034] During use, this device requires no additional positioning adjustments. The optical component 1, assembled with the dome structure 2, is simply placed on the bearing roller assembly 5 for low-frequency surface shape detection. After detection, the optical component 1 is removed, and the placement process is repeated for the next detection. The flexible spring structure 4 on the support base plate 3 automatically deforms to release radial force according to the placement of the optical component 1. The rolling contact between the roller 52 and the rolling ball 22 significantly reduces friction during sample loading / unloading and detection, ensuring consistent force conditions for each detection. This results in highly reproducible detection results, with an RMS value better than 0.1 nm during low-frequency surface shape detection of the optical component.

[0035] The above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit them; those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions will not cause the essence of the corresponding technical solutions to deviate from the protection scope of the present invention.

Claims

1. A support device for low-frequency surface shape detection of high-reproducibility optical devices, characterized in that, It includes a support base plate (3), three sets of bearing roller assemblies (5) and three dome structures (2). Three flexible spring sheet structures (4) are evenly distributed along the circumference of the support base plate (3). The bearing roller assemblies (5) and the flexible spring sheet structures (4) are fixedly connected one-to-one. The dome structures (2) are evenly distributed along the circumference and assembled on the optical device (1). The bearing roller assembly (5) includes a bearing housing (51), a roller (52), an angular contact bearing (53), a bearing retainer (54), and a rotating shaft. Two angular contact bearings (53) support a roller (52) to form a rolling contact point. The angular contact bearing (53) is pre-tightened by the bearing retainer (54) to eliminate its own clearance. The dome structure (2) forms a rolling fit contact with the bearing roller assembly (5), and the three sets of bearing roller assemblies (5) provide a total of six support points to constrain the six degrees of freedom of the optical device (1) in space.

2. The support device for low-frequency surface shape detection of high-reproducibility optical devices according to claim 1, characterized in that: The roller (52) is made of hard ceramic material or stainless steel material.

3. The support device for low-frequency surface shape detection of high-reproducibility optical devices according to claim 2, characterized in that: The surface of the roller (52) is coated with a wear-resistant and friction-reducing coating.

4. The support device for low-frequency surface shape detection of high-reproducibility optical devices according to claim 1, characterized in that: The rotating shaft includes a first rotating shaft (55) and a second rotating shaft (56), which are inserted from both ends of the bearing housing (51) and form an assembly fit with the angular contact bearing (53).

5. The support device for low-frequency surface shape detection of high-reproducibility optical devices according to claim 1, characterized in that: The dome structure (2) includes a dome body (21) and a rolling sphere (22). The dome body (21) has a hemispherical cavity adapted to the rolling sphere (22). The opening end of the hemispherical cavity has a closing structure. The rolling sphere (22) is embedded in the hemispherical cavity to form a rolling fit structure.

6. The support device for low-frequency surface shape detection of high-reproducibility optical devices according to claim 5, characterized in that: The dome body (21) is bonded and fixed to the optical device (1) with epoxy adhesive to form an integrated assembly structure.

7. The support device for low-frequency surface shape detection of high-reproducibility optical devices according to claim 5 or 6, characterized in that: The rolling sphere (22) is made of hard ceramic material or stainless steel material.

8. The support device for low-frequency surface shape detection of high-reproducibility optical devices according to claim 7, characterized in that: The surface of the rolling sphere (22) is coated with a wear-resistant and friction-reducing coating.

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