Lens and device for detecting dirt in lens

Abstract

A lens comprises a lens barrel, at least two lens bases are arranged in the lens barrel in the axial direction, axial limiting structures are arranged at the two ends of a through hole of the lens barrel, a lens is fixedly arranged in any lens base, any lens base and the lens barrel form a rotating pair in the circumferential direction, and a lens base rotating driving mechanism is arranged in the lens barrel. Rotatable design is adopted for the lens, each lens can independently rotate around the optical axis, and the lens is easy to implement and compatible with an existing clamp. The laser, the positive lens and the CCD camera are used for building a detection light path, the whole lens view field is covered through light beam expansion, micron-sized dust can be detected based on the diffraction principle, and the method is superior to a traditional visual or light transmission test. By rotating the lens and observing the movement of the diffraction ring, accurate positioning of dust is realized, the accuracy and high efficiency of detection are ensured, the number of dismounting times of the lens is reduced, blind dismounting is avoided, and the cleaning efficiency is improved. The whole detection process does not need direct contact with the lens, thereby reducing the physical damage risk and reducing the rejection rate of the lens.

Description

Technical Field

[0001] This invention relates to the field of physics, and more particularly to optical lenses, especially a lens and a device for detecting dirt inside the lens. Background Technology

[0002] Photolithography machines are core equipment in semiconductor manufacturing. Their internal lenses require extremely high cleanliness. Even in Class 100 cleanrooms, tiny dust particles (such as micron-sized particles) can adhere to the inside of the lens during assembly or use, making them difficult to detect with the naked eye. This dust causes light scattering or diffraction, altering optical path characteristics, affecting optical path quality, leading to imaging deviations or performance degradation, ultimately impacting lithography precision and product yield. Existing detection methods mainly include visual inspection, transmitted light testing, or microscopic observation. These methods are often insufficiently sensitive, especially when dust is located deep inside the lens, and cannot efficiently and accurately pinpoint the dust's exact location (a lens consists of multiple lenses arranged along the optical axis, making it impossible to determine which lens the dust is on). Often, the entire lens needs to be disassembled, and each lens manually inspected and cleaned—a tedious process that can easily introduce new contamination or cause mechanical damage, affecting lens lifespan and performance.

[0003] For example, one existing lens inspection system based on lasers and cameras uses a laser to emit a beam that illuminates the lens under test through a lens assembly, and then a CCD camera receives the image of the light spot. When there is dust inside the lens, the dust will block or scatter the light, causing abnormalities in the light spot (such as dark spots or bright spots). By analyzing the changes in the image, it is possible to determine whether there is contamination in the lens. However, this approach cannot pinpoint the exact location of the dust (i.e., which lens element it is located on), requiring the entire lens to be disassembled for individual inspection. Furthermore, some automated inspection systems utilize laser scanning or image processing technology, but these typically only detect the presence of dust and cannot achieve precise localization. Summary of the Invention

[0004] The purpose of this invention is to provide a lens and a lens internal dirt detection device to solve the technical problem in the prior art that it is difficult to determine the specific location of dust in a multi-lens lens.

[0005] The present invention provides a lens, including a lens barrel, in which at least two lens mounts are arranged axially, and axial limiting structures are provided at both ends of the through hole of the lens barrel. Each lens mount has a lens fixedly disposed therein, and each lens mount forms a circumferential rotating pair with the lens barrel. The lens barrel is provided with a lens mount rotation drive mechanism.

[0006] Furthermore, the lens mount rotation drive mechanism includes a turning tool, and a first through hole is provided on the side of each lens mount in the outer circumferential surface of the lens barrel. The turning tool can extend into the first through hole and contact the outer circumferential surface of the lens mount.

[0007] Alternatively, the lens mount rotation drive mechanism includes a toggle tool, and each lens mount has a second through hole on its end face. All the second through holes are coaxially arranged, and the toggle tool can extend into the second through hole to contact each lens mount.

[0008] Furthermore, the actuating tool is an L-shaped wrench.

[0009] Alternatively, the mirror mount rotation drive mechanism may include a number of motors equal to the number of mirror mounts, with the output shaft of each motor connected to one of the mirror mounts via a transmission mechanism.

[0010] The present invention provides a lens internal dirt detection device, comprising a light source, a positive lens, a lens bracket, the lens, a camera, and a camera bracket. The light source, the positive lens, the lens, and the camera are arranged in sequence. The positive lens is fixedly mounted on the lens bracket, the lens is fixedly mounted on the lens bracket, and the camera is fixedly mounted on the camera bracket.

[0011] Furthermore, the light source is a laser.

[0012] Furthermore, the camera mentioned is a CCD camera.

[0013] Furthermore, the camera's signal terminal is electrically connected to a display or a computer.

[0014] Compared with existing technologies, the advantages of this invention are positive and significant. The lens of this invention features a rotatable design, with each lens capable of independently rotating around the optical axis, making it easy to implement and compatible with existing fixtures. A detection optical path is constructed using a laser, a positive lens, and a CCD camera. By expanding the beam to cover the entire lens field of view, it can detect micron-sized dust particles based on the principle of diffraction, outperforming traditional visual or light transmission tests. Precise dust location is achieved by rotating the lenses and observing the movement of the diffraction rings, ensuring accuracy and efficiency in detection, reducing the number of lens disassemblies, avoiding blind disassembly, and improving cleaning efficiency. The entire detection process does not require direct contact with the lenses, reducing the risk of physical damage and lowering the lens scrap rate. Attached Figure Description

[0015] Figure 1 This is a three-dimensional schematic diagram of a lens according to the present invention.

[0016] Figure 2 This is a cross-sectional schematic diagram of a lens according to the present invention.

[0017] Figure 3 This is a schematic diagram of a lens internal dirt detection device according to the present invention. Detailed Implementation

[0018] The present invention will be further described below with reference to embodiments, but the present invention is not limited to these embodiments. Any similar variations of the present invention should be included within the scope of protection of the present invention. The use of directional terms such as up, down, front, back, left, right, center, inside, and outside in the present invention is only for the convenience of clear description and is not intended to limit the technical solution of the present invention.

[0019] like Figures 1-2 As shown, the present invention provides a lens including a lens barrel 4, in which at least two lens mounts 11 are arranged axially. The two ends of the through hole of the lens barrel 4 are provided with axial limiting structures. Each lens mount 11 is fixedly provided with a lens 10. Each lens mount 11 forms a circumferential rotating pair with the lens barrel 4. The lens barrel 4 is provided with a lens mount rotation drive mechanism.

[0020] Furthermore, the lens mount rotation drive mechanism includes a toggle tool. A first through hole 5 is provided on the side of each lens mount 11 in the outer circumferential surface of the lens barrel 4. The toggle tool can extend into the first through hole 5 and contact the outer circumferential surface of the lens mount 11.

[0021] Alternatively, the rotating drive mechanism for the mirror base includes a toggle tool, and each end face of any mirror base 11 is provided with a second through hole 12. All the second through holes 12 are coaxially arranged, and the toggle tool can extend into the second through hole 12 to contact each mirror base 11.

[0022] Furthermore, the actuating tool is an L-shaped wrench 6.

[0023] Alternatively, the mirror mount rotation drive mechanism may include a number of motors (not shown) equal to the number of mirror mounts 11, with the output shaft of each motor connected to one of the mirror mounts 11 via a transmission mechanism (not shown).

[0024] like Figure 3 As shown, the present invention provides a lens internal dirt detection device, including a light source, a positive lens 7, a lens bracket 3, the lens, a camera, and a camera bracket 2. The light source, the positive lens 7, the lens, and the camera are arranged in sequence. The positive lens 7 is fixedly mounted on the lens bracket 9, the lens is fixedly mounted on the lens bracket 3, and the camera is fixedly mounted on the camera bracket 2.

[0025] Furthermore, the light source is laser 8. Other coherent light sources (such as LEDs combined with collimating lenses) can also be used instead of laser 8, but laser 8 has better coherence and a more pronounced diffraction effect. Incoherent light sources may require additional filtering or processing steps.

[0026] Furthermore, the camera is a CCD camera 1. A CMOS camera or other types of photoelectric sensors can also be used instead of the CCD camera 1 to achieve image acquisition, but CMOS cameras typically have higher sensitivity and signal-to-noise ratio.

[0027] Furthermore, the camera's signal terminal is electrically connected to a display (not shown) or a computer (not shown). The computer can achieve automated detection by recognizing the movement of the diffraction rings. However, manually observing the image on the display is equally effective and more suitable for small-batch scenarios.

[0028] Specifically, beam splitters or reflectors can be introduced to change the optical path to adapt to different spatial layouts.

[0029] Specifically, the specific structures and principles of the light source, positive lens 7, camera, laser 8, CCD camera 1, display, and computer in this invention, as well as other aspects not described in detail, all adopt well-known solutions in the prior art, which are understood and implemented by those skilled in the art, and will not be elaborated here.

[0030] Working principle:

[0031] Laser 8 emits a coherent beam of light, which is expanded by positive lens 7 to increase its diameter and completely fill the lens's field of view, ensuring no area is missed. The expanded beam passes through the lens and is finally projected onto CCD camera 1. CCD camera 1 is connected to a display, which shows the spot image in real time.

[0032] Based on the principle of light diffraction, when a tiny dust particle is present on a lens element 10 inside the lens, the dust acts as a diffraction barrier, forming a distinct diffraction ring (such as an Airy disk or concentric rings) on the display. To locate the dust particle, the lens structure is designed to allow each lens element 10 to rotate independently with the lens mount 11. Using an L-shaped wrench 6 inserted into the first through-hole 5 or the second through-hole 12, the lens mount 11 can be rotated, allowing each lens element 10 to rotate 360° relative to the lens barrel 4 around the optical axis.

[0033] The testing process is as follows:

[0034] First, fix the lens on the lens holder 9 and adjust the optical path to allow the light beam to pass through normally.

[0035] Next, observe the initial light spot on the monitor. If diffraction rings appear, it indicates that there is dust inside the lens.

[0036] Next, rotate each lens 10 one by one (rotating only one lens 10 at a time) and observe the changes in the diffraction rings on the display. If the diffraction rings rotate with the lens 10, it means that the dust is located on that lens 10; if the diffraction rings do not rotate with the lens 10, it means that the dust is not on that lens 10.

[0037] Finally, remove the dusty lens 10, clean it, reassemble it, and test it again until no diffraction rings appear.

[0038] The lens of this invention features a rotatable design, with each lens 10 capable of independently rotating around the optical axis, making it easy to implement and compatible with existing fixtures. A detection optical path is constructed using a laser 8, a positive lens 7, and a CCD camera 1. By expanding the beam to cover the entire lens field of view, it can detect micron-sized dust particles based on the principle of diffraction, outperforming traditional visual or light transmission tests. Precise dust location is achieved by rotating the lens 10 and observing the movement of the diffraction rings, ensuring accuracy and efficiency in detection, reducing the number of lens disassemblies, avoiding blind disassembly, and improving cleaning efficiency. The entire detection process does not require direct contact with the lens 10, reducing the risk of physical damage and lowering the lens scrap rate.

Claims

1. A lens, characterized in that, The lens includes a lens barrel, in which at least two lens mounts are arranged axially. Axial limiting structures are provided at both ends of the through hole of the lens barrel. Each lens mount has a lens fixedly installed in it. Each lens mount forms a circumferential rotating pair with the lens barrel. The lens barrel is provided with a lens mount rotation drive mechanism.

2. A lens according to claim 1, characterized in that, The rotating drive mechanism for the lens mount includes a turning tool. A first through hole is provided on the side of each lens mount in the outer circumferential surface of the lens barrel. The turning tool can extend into the first through hole and contact the outer circumferential surface of the lens mount.

3. A lens according to claim 1, characterized in that, The rotating drive mechanism for the lens mount includes a turning tool. Each lens mount has a second through hole on its end face. All the second through holes are coaxially arranged. The turning tool can be inserted into the second through hole to contact each lens mount.

4. A lens according to claim 2 or 3, characterized in that, The aforementioned actuating tool is an L-shaped wrench.

5. A lens according to claim 1, characterized in that, The mirror mount rotation drive mechanism includes a number of motors equal to the number of mirror mounts, and the output shaft of each motor is connected to one of the mirror mounts through a transmission mechanism.

6. A lens internal dirt detection device, characterized in that, The device includes a light source, a positive lens, a lens bracket, the lens as described in claim 1, a camera, and a camera bracket. The light source, positive lens, lens, and camera are arranged in sequence. The positive lens is fixedly mounted on the lens bracket, the lens is fixedly mounted on the lens bracket, and the camera is fixedly mounted on the camera bracket.

7. The lens internal contamination detection device according to claim 6, characterized in that, The light source is a laser.

8. A lens internal contamination detection device according to claim 6, characterized in that, The camera mentioned is a CCD camera.

9. A lens internal contamination detection device according to claim 6, characterized in that, The camera's signal terminal is electrically connected to a display or a computer.

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