Processing and positioning method of optical element

Abstract

The invention relates to the field of optical lens manufacturing, in particular to a processing and positioning method of an optical element. According to the method, the coaxial alignment of the first optical element and the second optical element can be automatically realized by utilizing the magnetic attraction effect between the magnetic positioning structures on the corresponding surfaces of the first optical element and the second optical element. According to the automatic alignment mode, the interference of human factors is greatly reduced, and the positioning precision is remarkably improved. For example, for some optical systems with extremely high requirements on coaxiality, such as a high-precision microscope and a laser interferometer, the method can ensure that the coaxiality of the optical element reaches a micron level or even a submicron level, so that the performance of the optical system is effectively improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of optical lens manufacturing, in particular to a processing positioning method of an optical element. BACKGROUND

[0002] In the field of optical system manufacturing, the combination and cementation of rod lens and meniscus lens is a key process for constructing long-focus and high-magnification imaging components. Such combination is widely used in microscope objective, astronomical telescope and precise optical measurement equipment, and the cementation precision directly affects the light collimation and system imaging quality.

[0003] However, the traditional mechanical centering method is difficult to cope with the extreme size difference between rod lens and meniscus lens; for example, the thickness of rod lens can reach 33.7mm, while the thickness of meniscus lens is only 0.9mm, and the outer diameter of both is less than Φ8mm. When the mechanical clamp clamps the slender rod lens, a small deviation will cause the light deflection to be out of tolerance, and manual visual calibration is low in efficiency and large in precision fluctuation.

[0004] Therefore, with the development of optical system towards lightweight and integration, a new cementation process considering size difference and precision control is urgently needed to break through the technical bottleneck and realize stable mass production of high-precision optical components. SUMMARY

[0005] To solve the above problems, in one aspect, the present application discloses a processing positioning method of an optical element, comprising: a pretreatment step: rough machining the optical element to leave a subsequent machining allowance outside the magnetic positioning structure; forming a magnetic positioning structure on the corresponding surface of the first optical element and the second optical element to be cemented; a cementation step: fixing the second optical element on the clamp, and realizing coaxial alignment of the two by magnetic attraction between the magnetic positioning structure of the first optical element and the magnetic positioning structure of the second optical element; injecting optical cement when the contact gap of the optical element reaches a set value, applying a predetermined pressure until the glue is preliminarily solidified, and then forming a rigid connecting body through ultraviolet curing.

[0006] The magnetic positioning structure is a soft magnetic alloy layer formed by vacuum coating process, and the radial magnetic induction intensity of the soft magnetic alloy layer ranges from 50mT to 200mT, and the thickness ranges from 0.05mm to 0.2mm.

[0007] The clamp is provided with a displacement mechanism for fine adjustment of the position of the optical element.

[0008] In the glue injection step, the pressure on the cementation surface is monitored by a pressure sensor, and the pressure fluctuation range is controlled within ±10% of the set value; in the ultraviolet curing step, a 365nm ultraviolet light source is used, and the light intensity ranges from 500mW / cm 2 to 1000mW / cm 2 , and the rotation speed of the optical element during the curing process is 5-20r / min.

[0009] In another aspect, the application also discloses an optical element gluing system, comprising: a magnetic processing unit for forming a magnetic positioning structure on the surface of an optical element; a rough machining unit for rough machining the outer diameter of the optical element; a fixed clamp unit provided with a displacement mechanism for fine adjustment of the position of the optical element; a gluing control unit comprising a glue supply system, a pressure applying mechanism and an ultraviolet curing device; and a detection feedback unit for monitoring the position deviation of the optical element, the gluing surface pressure and the curing parameters.

[0010] The magnetic processing unit is a vacuum coating device, the vacuum degree of the vacuum coating device is ≤1×10 -3 Pa, and the sputtering power adjustment range is 30-100 W.

[0011] The rough machining unit is a numerical control machining device, the numerical control machining device is provided with a coaxiality detection module, and the detection accuracy of the coaxiality detection module is ≤1 μm.

[0012] The displacement adjustment mechanism of the fixed clamp unit comprises a three-dimensional micro-motion platform, and the displacement resolution of the micro-motion platform is ≤0.01 mm.

[0013] The detection feedback unit and the gluing control unit form a closed-loop control system, and when the monitored parameters exceed the set threshold, the alarm and process parameter correction are automatically triggered.

[0014] The method of the application utilizes the magnetic attraction between the magnetic positioning structures on the corresponding surfaces of the first optical element and the second optical element, and can automatically realize the coaxial alignment of the two. This automatic alignment method greatly reduces the interference of human factors, and significantly improves the positioning accuracy. For example, for some optical systems with extremely high coaxiality requirements, such as high-precision microscopes, laser interferometers, etc., the method can ensure that the coaxiality of the optical elements reaches the micron or even sub-micron level, thereby effectively improving the performance of the optical system. BRIEF DESCRIPTION OF DRAWINGS

[0015] Figure 1 A flowchart of the processing and positioning method of the optical element in the embodiment of the application;

[0016] Figure 2 A structural schematic diagram of the adsorption plate in the embodiment of the application;

[0017] Figure 3 A position schematic diagram of the magnetic ring in the rod lens and meniscus lens in the embodiment of the application. DETAILED DESCRIPTION

[0018] In order to make the inventive purposes, features and advantages of the present application more obvious and easy to understand, the technical solutions in the embodiments of the present application will be described clearly and completely below in conjunction with the drawings in the embodiments of the present application. Obviously, the embodiments described below are only a part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative efforts fall within the scope of protection of the present application. The principles and features of the present application are described below in conjunction with the drawings, and the examples are used to explain the present application, but not to limit the scope of the present application.

[0019] The term "comprising" and other similar expressions in the description and claims of the present application and the above drawings means covering the non-exclusive inclusion, such as the process, method or system, device including a series of steps or units, which is not limited to the listed steps or units.

[0020] Embodiment 1: As shown in the figure, a processing positioning method of an optical element, comprising: Figure 1

[0021] S101: Rough machining is performed on the optical element, and a subsequent machining allowance is reserved at the outer edge of the magnetic positioning structure; for example, the outer diameter of the optical element is roughly ground to be greater than the finished product size, such as a rod lens Φ6.95 and a meniscus lens Φ6.5, so that a subsequent edge grinding allowance is reserved at the outer edge of the magnetic positioning structure;

[0022] The outer diameter size error is ≤±0.05mm, and the coaxiality error of the outer edge of the magnetic structure is ≤10μm, which lays a foundation for subsequent coaxial alignment.

[0023] S102: Forming a magnetic positioning structure on the corresponding surface of the first optical element and the second optical element to be glued;

[0024] In an embodiment, a soft magnetic alloy layer can be iron-nickel alloy is plated on the corresponding surface of the first and second optical elements by vacuum plating; the specific layer thickness is 0.05-0.2mm, the radial magnetic induction intensity is 50-200mT, which ensures that the magnetic attraction intensity is sufficient to align the elements, while avoiding affecting the optical performance.

[0025] Gluing step:

[0026] S103: Fixing the second optical element to the clamp, and realizing coaxial alignment of the two by the magnetic attraction between the magnetic positioning structure of the first optical element and the magnetic positioning structure of the second optical element;

[0027] ​The second optical element, for example, a meniscus lens, is fixed by a clamp, and a displacement fine adjustment mechanism is built in the clamp. The displacement fine adjustment mechanism can be a three-dimensional fine adjustment platform, by which the position of the element can be manually / automatically adjusted. By using the magnetic attraction of the first optical element, for example, a rod lens, and the magnetic structure of the second element, coaxial alignment is automatically achieved, replacing the traditional manual calibration, and the operation difficulty and error are reduced.

[0028] S104: When the contact gap of the optical element reaches a set value, optical glue is injected, a predetermined pressure is applied and maintained until the glue is preliminarily solidified, and then ultraviolet curing is performed to form a rigid connecting body.

[0029] During implementation, the pressure on the gluing surface can be monitored in real time by a pressure sensor, and the fluctuation range is ≤±10% of the set value, so as to ensure that the glue uniformly fills the gap. In this embodiment, when the contact gap of the element reaches a set value of 0.05 mm, low-shrinkage optical glue is injected.

[0030] In the ultraviolet curing process, 365 nm ultraviolet light (light intensity 500-1000 mW / cm 2 ) is used; the element is rotated at 5-20 revolutions per minute to accelerate the curing of the glue, and the curing degree is ≥90% within 2 minutes to form a rigid connecting body.

[0031] The scheme of this embodiment completes coaxial calibration by constructing a magnetic positioning structure on the surface of the optical element and using magnetic attraction. It is especially suitable for small-size and large-thickness-difference elements, significantly shortens the gluing centering time, and improves the operation efficiency; the magnetic attraction self-alignment reduces the risk of eccentricity, can ensure the parallelism of the lens, and reduces the scrap rate.

[0032] At the same time, a margin is reserved outside the magnetic structure during rough machining, which provides space for subsequent edge grinding correction. If there is a position deviation after gluing, the margin can be adjusted to compensate, avoiding scrapping due to one-step forming; the dependence on single-process precision is reduced, and the overall good product rate is improved.

[0033] The curing process uses a rotation process combined with an ultraviolet light source. Rotation curing reduces shrinkage and deformation, and improves the qualified rate of finished products.

[0034] Referring to Figure 3 , for example, taking a rod lens 200 and a meniscus lens 300 as an example, in specific operation, a numerical control grinding machine is used to grind the rod lens to Φ6.95±0.03 mm (0.25 mm margin is reserved in the magnetic ring area), and the meniscus lens is ground to Φ6.5±0.02 mm, so as to ensure that the coaxiality error of the outer circle of the magnetic ring area is <5 μm. At the position 201 (to-be-machined surface) of the bottom end of the rod lens and the symmetric position 301 of the edge of the meniscus lens (gluing surface), a soft magnetic alloy ring with a thickness of 0.1 mm is plated by a vacuum sputtering method (outer diameter Φ7.2 / Φ6.8, matched with the subsequent edge grinding margin), and the radial magnetic induction intensity of the magnetic ring is controlled at 50-80 mT, so as to form a magnetic reference surface that can be adsorbed and positioned.

[0035] Cylindrical and meniscus lenses are placed on the fixture and fixed by vacuum suction;

[0036] The cylindrical lens is vertically lifted to the gluing station, and the preliminary coaxial alignment is achieved by using the magnetic ring suction force. A micro-displacement table is used to press down at a speed of 0.01 mm / s, and at the same time, the machine vision system is used to monitor the gap change between the gluing surfaces. When the gap is reduced to 0.05 mm, low-viscosity optical glue is injected, and a pressure of 0.5 N / mm 2 The uniform pressure is maintained for 30 seconds to preliminarily cure the glue in the magnetic positioning state.

[0037] Turn on the 365 nm ultraviolet light source (light intensity 800 mW / cm 2 ), and rotate the fixture at 10 revolutions per minute to ensure uniform curing of the glue layer to form a rigid connection body.

[0038] Embodiment 2: An optical element gluing system, comprising: a magnetic processing unit for forming a magnetic positioning structure on the surface of an optical element; a rough machining unit for rough machining the outer diameter of the optical element; a fixed clamp unit provided with a displacement mechanism for fine adjustment of the position of the optical element; a gluing control unit including a glue supply system, a pressure applying mechanism and an ultraviolet curing device; a detection feedback unit for monitoring the position deviation of the optical element, the gluing surface pressure and the curing parameters.

[0039] The magnetic processing unit is a vacuum coating device, and the vacuum degree of the vacuum coating device is ≤1×10-3Pa, and the sputtering power adjustment range is 30-100W. The main function of the magnetic processing unit is to form a magnetic positioning structure on the surface of the optical element. The magnetic positioning structure is crucial for the subsequent gluing and positioning of the optical element. It can realize automatic coaxial alignment of the optical element by using magnetic force, and improve the precision and efficiency of gluing.

[0040] Specifically, a vacuum coating device can be used to realize the formation of the magnetic positioning structure. The vacuum degree is ≤1×10-3Pa, and the high vacuum environment helps to reduce the influence of impurities on the coating process, ensuring the quality of the magnetic positioning structure. The sputtering power adjustment range is 30-100W, and by adjusting the sputtering power, the speed and quality of the coating can be controlled to adapt to the needs of different types of optical elements and magnetic positioning structures.

[0041] The rough machining unit is a numerical control machining device, which is equipped with a coaxiality detection module, which can be a laser interferometer or a coordinate measuring machine, and the detection accuracy of the coaxiality detection module is ≤1 μm. The outer diameter of the optical element is rough machined. Before cementing, the outer diameter of the optical element needs to be machined to a suitable size, and a certain allowance is reserved for subsequent fine machining, so that the deviation that may occur in the subsequent process can be corrected. The use of numerical control machining equipment for rough machining can ensure the accuracy and consistency of machining. The numerical control machining equipment is equipped with a coaxiality detection module, and the detection accuracy is ≤1 μm. The coaxiality detection module can monitor the coaxiality of the optical element in the rough machining process in real time, and ensure that the machined optical element meets the requirements of subsequent cementing.

[0042] In an embodiment, the displacement adjustment mechanism of the fixed clamp unit comprises a three-dimensional micro-motion platform, and the displacement resolution of the micro-motion platform is ≤0.01 mm. During cementing, the optical element needs to be accurately positioned, and the displacement mechanism can accurately adjust the position of the optical element according to the actual situation to ensure the accuracy of cementing. The three-dimensional micro-motion platform can fine-tune the position of the optical element in three dimensions, and the high-resolution displacement adjustment capability can realize very accurate position adjustment, thereby improving the quality of cementing.

[0043] In another embodiment, referring to Figure 2 , the clamp comprises a hollow adsorption plate 100, one end of the adsorption plate is connected to a vacuum pumping device, and a plurality of adsorption holes are formed in the top surface of the adsorption plate. A negative pressure is formed by the vacuum pumping device to adsorb and fix the mirror body to be machined. Specifically, it can be installed on the above-mentioned three-dimensional micro-motion platform, and the mirror body fixed on the adsorption plate is adjusted by the three-dimensional micro-motion platform.

[0044] The detection feedback unit and the cementing control unit constitute a closed-loop control system, which automatically triggers an alarm and process parameter correction when the monitored parameters exceed the set threshold. The system can specifically include a glue supply system, a pressure applying mechanism and an ultraviolet curing device. The glue supply system is responsible for uniformly injecting an appropriate amount of glue into the cementing surface of the optical element; the pressure applying mechanism applies a predetermined pressure to the cemented optical element, so that the glue can fully fill the cementing surface and ensure the tightness of the cementing; and the ultraviolet curing device uses ultraviolet rays to cure the glue, so that the optical elements are firmly cemented together.

[0045] The detection feedback unit is used to monitor the position deviation of the optical element, the pressure of the cementing surface and the curing parameters. By monitoring these parameters in real time, problems that may occur during cementing can be found in time, such as excessive position deviation, abnormal pressure or curing parameters not meeting the requirements.

[0046] The detection feedback unit and the gluing control unit constitute a closed-loop control system.

[0047] The technical means disclosed in the present application are not limited to the technical means disclosed in the above embodiments, but also include technical solutions composed of any combination of the above technical features.

[0048] Without departing from the principles of the present application, those skilled in the art can make several improvements and refinements, which are also considered within the scope of protection of the present application.

[0049] of the present application.

Claims

1. A method for processing and positioning an optical element, characterized in that, include: Preprocessing step: The optical element is rough-machined to allow for subsequent machining allowance on the outer edge of the magnetic positioning structure; A magnetic positioning structure is formed on the corresponding surfaces of the first and second optical elements to be bonded; bonding steps: the second optical element is fixed to the fixture, and the magnetic attraction between the magnetic positioning structure of the first optical element and the magnetic positioning structure of the second optical element is used to achieve coaxial alignment of the two; when the contact gap of the optical elements reaches the set value, optical adhesive is injected, a predetermined pressure is applied and held until the adhesive is initially cured, and then a rigid connector is formed by ultraviolet curing.

2. The method according to claim 1, characterized in that, The magnetic positioning structure is a soft magnetic alloy layer formed by vacuum coating process. The radial magnetic induction intensity of the soft magnetic alloy layer ranges from 50 to 200 mT, and the thickness ranges from 0.05 to 0.2 mm.

3. The method according to claim 1, characterized in that, The fixture is equipped with a displacement mechanism for fine-tuning the position of the optical elements.

4. The method according to claim 1, characterized in that, In the adhesive injection step, the pressure on the bonding surface is monitored by a pressure sensor, and the pressure fluctuation range is controlled within ±10% of the set value; in the ultraviolet curing step, a 365nm ultraviolet light source is used, with a light intensity range of 500-1000mW / cm². 2 During the curing process, the rotation speed of the optical components is 5-20 revolutions per minute.

5. An optical element bonding system according to any one of claims 1-4, characterized in that, include: Magnetic processing unit, used to form magnetic positioning structures on the surface of optical elements; The roughing unit is used to roughen the outer diameter of optical components; The fixing fixture unit is equipped with a displacement mechanism for fine-tuning the position of optical components; the bonding control unit includes an adhesive supply system, a pressure application mechanism, and an ultraviolet curing device. The detection feedback unit is used to monitor the positional deviation of optical components, adhesive surface pressure, and curing parameters.

6. The bonding system according to claim 5, characterized in that, The magnetic processing unit is a vacuum coating equipment, the vacuum degree of which is ≤1×10-3Pa and the sputtering power adjustment range is 30-100W.

7. The bonding system according to claim 5, characterized in that, The roughing unit is a CNC machining equipment, which is equipped with a coaxiality detection module with a detection accuracy of ≤1μm.

8. The bonding system according to claim 5, characterized in that, The displacement adjustment mechanism of the fixed clamp unit includes a three-dimensional micro-motion platform, and the displacement resolution of the micro-motion platform is ≤0.01mm.

9. The bonding system according to claim 5, characterized in that, The detection feedback unit and the bonding control unit form a closed-loop control system. When the monitored parameters exceed the set threshold, an alarm is automatically triggered and the process parameters are corrected.

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