Optical lens with dispersion compensation function, lens and camera module
By plating an abnormal dispersion film on the optical lens body, the dispersion problem during the optical lens imaging process is solved, high-quality imaging is achieved, and production costs are reduced.
Patent Information
- Application Number
- CN202411747964.2
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-12-02
- Publication Date
- 2025-02-14
AI Technical Summary
The existing optical lenses have dispersion problems during the imaging process, which affects the chromatic purity and clarity of imaging. The existing low-dispersion optical lenses are costly and can only reduce dispersion to a certain extent.
An abnormal dispersion film is plated on the optical lens body, and a SiO2 film is formed by a physical vapor deposition process. The refractive index of the film changes symmetrically and periodically along the film thickness direction to compensate for the dispersion of the lens.
Through the compensation of the abnormal dispersion film, the dispersion phenomenon of the lens is basically eliminated, the imaging quality is significantly improved, and the production cost of the lens is reduced.
Smart Images
Figure CN119439326A_ABST
Abstract
Description
Technical Field
[0001] The present invention belongs to the field of optical lenses, and in particular relates to an optical lens, a lens and a camera module with dispersion compensation function. Background Art
[0002] In recent years, with the widespread use of mobile phones, people have higher and higher requirements for mobile phone camera functions, and the quality of mobile phone photography depends largely on the imaging quality of the lens of its camera module. However, both glass lenses and plastic lenses have dispersion phenomenon. With the existing optical lens structure, the dispersion of the optical lens directly affects the color purity and clarity of the image. Although there are also low-dispersion optical lenses that improve the material of optical lenses, their cost is high and expensive, and they can only reduce dispersion to a certain extent and still have dispersion phenomenon. Summary of the invention
[0003] In view of the above-mentioned deficiencies in the prior art, the technical problem to be solved by the present invention is to provide an optical lens, a lens and a camera module with dispersion compensation function.
[0004] In order to solve the above technical problems, the present invention provides the following technical solutions:
[0005] An optical lens with a dispersion compensation function comprises a lens body, on which an abnormal dispersion film is plated. The abnormal dispersion film is a film with abnormal dispersion performance in the visible light range and is used to compensate for the dispersion of the lens body.
[0006] Furthermore, an anti-reflection film is provided on the anomalous dispersion film; or
[0007] An anti-reflection film is arranged on the lens body, and the anomalous dispersion film is arranged on the anti-reflection film.
[0008] Furthermore, the anomalous dispersion film is formed by depositing on the surface of the lens body using a physical vapor deposition process.
[0009] Furthermore, when the anomalous dispersion film is formed by adopting the physical vapor deposition process, the distance between the evaporation source of the coating machine and the rotation center of its substrate frame is increased to increase the uniform area of the anomalous dispersion film.
[0010] Furthermore, when the anomalous dispersion film is formed by adopting the physical vapor deposition process, by selecting the rotation speed of the substrate holder, the incident angle of the evaporated molecules is continuously changed while the thickness of the anomalous dispersion film increases, so that the aggregation density and refractive index of the anomalous dispersion film are also changed accordingly; every time the substrate holder rotates one circle, a symmetrical periodic structure with a continuously changing refractive index is formed in the growth direction of the anomalous dispersion film.
[0011] Furthermore, the anomalous dispersion film is a SiO2 film deposited on the surface of the lens body using a large-aperture coating machine, and the refractive index of the SiO2 film in the visible light band remains unchanged as the wavelength increases, or the refractive index of the SiO2 film changes symmetrically and periodically along the film thickness direction.
[0012] Furthermore, the relevant parameters for preparing SiO2 thin films are: the aperture of the coating machine is greater than or equal to 1.1m, the rotation radius of the sample plate is 250mm~350mm, the rotation speed of the substrate holder is 0.2r / min~0.25r / min, the deposition rate is 0.25nm / s~0.35nm / s, and the period is 70nm~90nm.
[0013] Furthermore, the lens body is a glass lens or a plastic lens.
[0014] A lens with dispersion compensation function comprises at least one optical lens with dispersion compensation function.
[0015] A camera module with a dispersion compensation function comprises a lens with the dispersion compensation function.
[0016] In the present invention, a layer of abnormal dispersion film is added to the lens body, and the abnormal dispersion film can compensate for the chromatic aberration of the lens, greatly improving the imaging quality of the lens. When the dispersion performance of the lens and the abnormal dispersion performance reach a balance, the dispersion phenomenon can be basically eliminated, providing a new idea for the development prospects of the lens industry. BRIEF DESCRIPTION OF THE DRAWINGS
[0017] The drawings described herein are used to provide a further understanding of the present application and constitute a part of the present application. The illustrative embodiments of the present application and their descriptions are used to explain the present application and do not constitute an improper limitation on the present application. In the drawings:
[0018] Figure 1 This is a schematic diagram of the image formed by visible light passing through an ordinary optical lens.
[0019] Figure 2 Schematic diagram of the formation of visible light after passing through a low light dispersion optical lens.
[0020] Figure 3 It is a schematic structural diagram of an embodiment of an optical lens with dispersion compensation function of the present invention.
[0021] Figure 4 It is a schematic diagram of the image formed after visible light passes through the optical lens with dispersion compensation function of this embodiment.
[0022] Figure 5 It is a schematic diagram of the relationship curve between the film thickness and the refractive index of the anomalous dispersion film in a specific example.
[0023] The accompanying drawings in the specification are as follows:
[0024] Ordinary optical lens-100; low dispersion optical lens-200; optical lens with dispersion compensation function-300; lens body-310; anomalous dispersion film-320; anti-reflection film-330. DETAILED DESCRIPTION
[0025] The following describes the implementation methods of the present invention through specific examples. The illustrations provided in the following embodiments are only used to schematically illustrate the basic concept of the present invention. The following embodiments and features in the embodiments may be combined with each other without conflict.
[0026] The main reason for the dispersion of optical lenses is the difference in refractive index when light of different wavelengths passes through the lens. Figure 1 When complex color light (such as white light) passes through the ordinary optical lens 100, due to the different refractive indices of light of different wavelengths, it cannot be focused on the same point, thus forming an imaging aberration of color spots, that is, dispersion. Dispersion will cause light to scatter, making the image unclear. In addition, since different colors of light are refracted to different degrees, the color of the image will be distorted.
[0027] Low dispersion optical lens 200 is a lens with a particularly low dispersion rate for certain light wavelengths, which can effectively reduce the dispersion phenomenon produced by optical lenses. Figure 2 The low-dispersion optical lens 200 uses special optical glass materials. These special optical glass materials have a large dispersion coefficient (Vd), which can effectively reduce the difference in the refractive index of the lens at different wavelengths, thereby reducing the difference in the refractive index of the lens for light of different wavelengths. When light passes through the low-dispersion optical lens 200, light of different wavelengths can be more evenly focused within a smaller range, thereby reducing the impact of dispersion and chromatic aberration on imaging quality and improving imaging quality. However, the low-dispersion optical lens 200 still has a certain dispersion phenomenon, and these special optical glass materials are relatively expensive, which greatly increases the production cost of the lens.
[0028] In view of the above situation, the present invention discloses an optical lens with dispersion compensation function. Figure 3 An embodiment of an optical lens with dispersion compensation function of the present invention includes a lens body 310, which can be a glass lens or a plastic lens. An abnormal dispersion film 320 is plated on the lens body 310, and the abnormal dispersion film 320 is a film with abnormal dispersion performance in the visible light range, and the abnormal dispersion film 320 is used to compensate for the dispersion of the lens body 310. Of course, Figure 3It is only a schematic diagram and is not used to limit the actual shape of the lens body 310 and the actual thickness ratio of each film layer to the lens body 310.
[0029] Since the technology of coating multilayer films for optical lenses is relatively mature, in order to reduce the reflection of visible light by the optical lens and increase the anti-reflection rate of the lens, an anti-reflection film 330 can be arranged on the anomalous dispersion film 320. Of course, the anti-reflection film 330 can also be arranged on the lens body 310, and the anomalous dispersion film 320 can be arranged on the anti-reflection film 330. Therefore, when the anomalous dispersion film 320 is added in this embodiment, the arrangement of the original anti-reflection film 330 is not affected, so that a two-layer or multi-layer film structure can be formed on the lens body 310.
[0030] See also Figure 4 , Figure 4 The diagram is a schematic diagram of imaging of visible light after passing through the optical lens 300 with dispersion compensation function of this embodiment. Since the anomalous dispersion film 320 is used to compensate for the dispersion of the lens body 310, the dispersion of the lens is almost eliminated, so that the visible light is almost converged on the focal plane after passing through the optical lens 300 with dispersion compensation function, thereby greatly improving the clarity, compensating for the chromatic aberration of the imaging, and greatly improving the imaging quality of the optical lens.
[0031] The anomalous dispersion film 320 can be formed by depositing on the surface of the lens body 310 using a PVD (Physical Vapor Deposition) process. The PVD process is to use a physical process to achieve material transfer, transferring atoms or molecules from a source to the surface of a substrate. The principle of the PVD process is to use a low-voltage, high-current arc discharge technology under vacuum conditions, use gas discharge to evaporate the target material and ionize both the evaporated material and the gas, and use the acceleration of the electric field to deposit the evaporated material and its reaction products on the workpiece. The film layer coated by the PVD process is relatively thin. In this embodiment, the film layer thickness of the anomalous dispersion film 320 is only a few hundred nanometers, so it hardly affects the original size of the lens body 310. The film layer coated by the PVD process has a stronger bonding force with the surface of the lens body 310, a higher hardness, better wear resistance and corrosion resistance, and a more stable performance of the film layer.
[0032] In order to make the film layer have abnormal dispersion performance, when the abnormal dispersion film 320 is formed by the physical vapor deposition process, the evaporation source of the coating machine is generally moved away from the rotation center of its substrate frame (that is, the distance between the evaporation source and the rotation center of the substrate frame is increased) to increase the uniform area of the abnormal dispersion film 320. In addition, the degree of abnormal dispersion of the abnormal dispersion film 320 is related to the amplitude and period of the refractive index change. The larger the refractive index change period in the thickness direction of the abnormal dispersion film 320, the more obvious the abnormal dispersion phenomenon is, and the influence of the refractive index change amplitude is second. Therefore, by properly controlling the process parameters during the preparation of the film, the equivalent refractive index of the obtained film can show abnormal dispersion characteristics in the investigated band.
[0033] In the experiment, the refractive index variation period can be adjusted by changing the substrate rack rotation speed. When the substrate rack rotation speed reaches a certain speed, the deposited film shows normal dispersion. Therefore, when the abnormal dispersion film 320 is formed by the physical vapor deposition process, the incident angle of the evaporated molecules is continuously changed while the thickness of the abnormal dispersion film 320 increases by selecting the substrate rack rotation speed; due to the low mobility and shadow effect of the deposited molecules, the aggregation density and refractive index of the abnormal dispersion film 320 are also changed accordingly. When the range of the incident angle of the evaporated molecules on the deposition surface is large, the refractive index variation amplitude of the formed film in the film thickness direction will also be large, and the prepared film is easy to show abnormal dispersion characteristics. By changing the film deposition rate and the substrate rack rotation speed, the deposition refractive index variation period can be adjusted. Every time the substrate rack rotates one circle, a symmetrical periodic structure with continuous refractive index variation is formed in the growth direction of the abnormal dispersion film 320.
[0034] In this embodiment, the anomalous dispersion film 320 can be a SiO2 film deposited on the surface of the lens body 310 using a large-aperture coating machine. The refractive index of the SiO2 film in the visible light band remains unchanged as the wavelength increases, or the refractive index of the SiO2 film changes symmetrically and periodically along the film thickness direction, thereby exhibiting anomalous dispersion characteristics.
[0035] When the SiO2 film is prepared on the surface of the lens body 310 by the PVD process, the following parameters may be used:
[0036] Coating machine diameter: ≥1.1m
[0037] Rotation radius of sample plate: 250mm~350mm
[0038] The rotation speed of substrate rack: 0.2r / min~0.25r / min
[0039] Deposition speed: 0.25nm / s~0.35nm / s
[0040] Period: 70nm~90nm
[0041] In this embodiment, the aperture of the coating machine is 1.1 m, the rotation radius of the sample plate is 300 mm, the rotation speed of the substrate holder is 0.225 r / min, the deposition speed is 0.3 nm / s, and the period is 80 nm.
[0042] See also Figure 5 , Figure 5 The horizontal axis in the figure is the film thickness of the anomalous dispersion film 320, the vertical axis is the refractive index, and ρ represents the rotation radius of the sample plate. Figure 5 The solid line in FIG. 1 is a curve showing the relationship between the film thickness and the refractive index of the anomalous dispersion film 320 obtained by the PVD process using the above parameters. It can be seen that as the film thickness increases, the refractive index changes periodically between 1.36 and 1.46. Figure 5 The dotted line in FIG. 1 is a curve showing the relationship between the film thickness and the refractive index of the anomalous dispersion film 320 when the rotation radius of the sample plate is equal to 100 mm. At this time, the variation range of the refractive index is greatly reduced, and it is difficult to meet the dispersion compensation requirements.
[0043] In the present embodiment, a layer of anomalous dispersion film 320 is added to the lens body 310, and the structure of the anti-reflection film 330, which is currently the most commonly used structure in mobile phone lenses, is changed to a structure of the anti-reflection film 330 plus the anomalous dispersion film 320. The chromatic aberration of the lens can be compensated by the anomalous dispersion film 320, which greatly improves the imaging quality of the lens and provides a new idea for the development prospects of the lens industry.
[0044] The present invention also discloses a lens with a dispersion compensation function. An embodiment of the lens with a dispersion compensation function of the present invention comprises a lens group, at least one lens in the lens group adopts an optical lens with a dispersion compensation function of any of the above embodiments, so that the dispersion of the lens is compensated by the optical lens with a dispersion compensation function. When the dispersion performance of the lens reaches a balance with the abnormal dispersion performance, the dispersion can be basically eliminated, thereby greatly improving the imaging quality of the lens.
[0045] The present invention also discloses a camera module with a dispersion compensation function. An embodiment of the camera module with a dispersion compensation function of the present invention includes a lens, and the lens adopts the lens with a dispersion compensation function of any of the above embodiments. After the camera module adopts the lens with a dispersion compensation function, since the lens can compensate for dispersion, it has a very high imaging quality, and thus can also greatly improve the imaging quality of the camera module.
[0046] The above embodiments only express the preferred implementation modes of the present invention, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the invention patent. It should be pointed out that, for those of ordinary skill in the art, several variations and improvements can be made without departing from the concept of the present invention, and these all belong to the protection scope of the present invention. Therefore, the protection scope of the patent of the present invention shall be subject to the attached claims.
Claims
1. An optical lens with dispersion compensation function, characterized in that: The lens body comprises a lens body on which an abnormal dispersion film is plated. The abnormal dispersion film is a film with abnormal dispersion performance in the visible light range and is used to compensate for the dispersion of the lens body.
2. The optical lens with dispersion compensation function as claimed in claim 1, characterized in that: An anti-reflection film is provided on the anomalous dispersion film; or An anti-reflection film is arranged on the lens body, and the anomalous dispersion film is arranged on the anti-reflection film.
3. The optical lens with dispersion compensation function as claimed in claim 1, characterized in that: The anomalous dispersion film is formed by depositing on the surface of the lens body by using a physical vapor deposition process.
4. The optical lens with dispersion compensation function as claimed in claim 3, characterized in that: When the anomalous dispersion film is formed by the physical vapor deposition process, the distance between the evaporation source of the coating machine and the rotation center of its substrate frame is increased to increase the uniform area of the anomalous dispersion film.
5. The optical lens with dispersion compensation function as claimed in claim 3, characterized in that: When the anomalous dispersion film is formed by the physical vapor deposition process, the rotation speed of the substrate holder is selected so that the incident angle of the evaporated molecules changes continuously while the thickness of the anomalous dispersion film increases, thereby causing the aggregation density and refractive index of the anomalous dispersion film to change continuously accordingly; each time the substrate holder rotates one circle, a symmetrical periodic structure with a continuously changing refractive index is formed in the growth direction of the anomalous dispersion film.
6. The optical lens with dispersion compensation function according to any one of claims 3 to 5, characterized in that: The anomalous dispersion film is a SiO2 film deposited on the surface of the lens body by a large-aperture coating machine. The refractive index of the SiO2 film in the visible light band remains unchanged as the wavelength increases, or the refractive index of the SiO2 film changes symmetrically and periodically along the film thickness direction.
7. The optical lens with dispersion compensation function as claimed in claim 6, characterized in that: The relevant parameters for preparing SiO2 thin films are: the aperture of the coating machine is greater than or equal to 1.1m, the rotation radius of the sample plate is 250mm~350mm, the rotation speed of the substrate holder is 0.2r / min~0.25r / min, the deposition rate is 0.25nm / s~0.35nm / s, and the period is 70nm~90nm.
8. The optical lens with dispersion compensation function as claimed in claim 1, characterized in that: The lens body is a glass lens or a plastic lens.
9. A lens with dispersion compensation function, characterized in that: The optical lens comprises at least one optical lens with dispersion compensation function as claimed in any one of claims 1 to 8.
10. A camera module with dispersion compensation function, characterized in that: Comprising the lens with dispersion compensation function as claimed in claim 9.