Optical system having methacrylate resin

Abstract

An optical system including at least one lens formed from a methacrylate-based copolymer or a monomer polymer thereof, and at least another lens formed from the methacrylate-based copolymer or a monomer polymer thereof, or a different material; in the optical system, the difference value Vdmax-Vdmin between the Abbe number Vdmax of the lens having the maximum positive refractive power and the Abbe number Vdmin of the lens having the minimum Abbe number is greater than or equal to 18.

Description

Technical Field

[0001] The present invention relates to an optical system, and more particularly to an optical system including an optical element formed of a polymer or copolymer of a methacrylate monomer. Background Art

[0002] In recent years, optical resin materials have been widely used for lenses in camera modules of mobile terminals such as mobile phones, automobiles, surveillance cameras, AR / VR, etc. Existing optical resins are classified into high-dispersion resins and low-dispersion resins according to the dispersion coefficient.

[0003] High-dispersion resins mainly include special polycarbonate copolymers, such as the EP series of Mitsubishi Gas Chemical, the PC and SP series of Teijin, and the OKP series of Osaka Gas of special polyester fibers. These existing high-dispersion resins are characterized by a low Abbe number.

[0004] Low-dispersion resins mainly include the cycloolefin copolymer (COC) of Apel (APEL) manufactured by Mitsui Chemicals, the cycloolefin copolymer (COP) of Zeonex (ZEONEX) manufactured by Zeon Corporation of Japan, and the Arton cycloolefin resin manufactured by JSR Corporation. These existing low-dispersion resins are characterized by a high Abbe number;

[0005] However, the disadvantages of the above existing resin materials are as follows: First, the material cost is relatively high; second, there is a lack of a medium Abbe number range of 38-50 and a high Abbe number range of 56 or more, resulting in low application flexibility and limited functions of the optical system. However, the above existing resins are used in existing optical systems.

[0006] For example, Patent Document 1 discloses a photographic system including 5 lenses, and Patent Document 2 discloses a photographic lens group including 3 lenses. The disadvantages of these two optical systems in the prior art are: 1. Using existing resin materials, the cost is relatively high; 2. No new resin materials have been developed, the cost performance is low, and the application is limited.

[0007] In addition to the above existing resin materials, there is also a new resin material including a high Abbe number range and a medium Abbe number range, which has not been widely used in optical systems such as mobile phone lenses. This is a resin containing a variety of methacrylate monomer polymers and a methacrylate copolymer capable of adjusting the Abbe number. The advantages are: 1. The material cost is relatively low, 2. It includes a medium-high Abbe number range (36-66); 3. By synthesizing copolymers with different methacrylate monomers, resin materials with different Abbe numbers can be formed; 4. It can be used for an achromatic lens system composed of a lens combination formed of methacrylate copolymer materials. The disadvantage of this material is that it does not include a low Abbe number range below 36 and a high Abbe number range above 66.

[0008] If a lens combination formed entirely of a methacrylate copolymer is used for achromatism, a good lens achromatism effect can be achieved, and at the same time, the cost can be reduced. However, there are the following defects: Since the difference between the maximum Abbe number and the minimum Abbe number of lenses made of the same material is small, for example, when the difference in the maximum and minimum Abbe numbers of the lens, Vd1 - Vd2, is less than 10, axial chromatic aberration can be eliminated, but it is not conducive to simultaneously correcting aberrations such as spherical aberration and taking into account the achromatism function. In addition, since the glass transition temperature points of some monomer materials used to make the lenses are low, in order to meet the operating temperature above a certain standard, the synthesis ratio of such monomer materials needs to be reduced. This will cause the difference between the high Abbe number and the low Abbe number of the synthesized copolymer to be smaller than that of the original monomer polymer (the Abbe number range of the material is lower), resulting in a smaller difference between the maximum and minimum Abbe numbers, which further affects the realization of the functions of the lens to simultaneously meet achromatism and aberration correction. It is not conducive to the research and development and manufacture of high-performance optical systems (such as mobile phone lenses, etc.) that can simultaneously achieve aberration correction and achromatism functions.

[0009] In summary, in the prior art, whether it is the lens system in Patent Documents 1 and 2 or the optical system composed of the above-mentioned existing resin materials of methacrylate copolymers, it is difficult to form a high-performance optical system that can simultaneously achieve aberration correction and achromatism functions. In view of this, there is an urgent need to develop a high-performance optical system that can simultaneously achieve aberration correction and achromatism functions.

[0010]

References

[0011] Patent Document 1: CN202710832U

[0012] Patent Document 2: CN1790086A Summary of the Invention

[0013] In order to solve the problem that it is difficult for the optical systems in the prior art to simultaneously achieve aberration correction and achromatism functions, the present invention provides an optical system including a lens group composed of a methacrylate copolymer or a methacrylate monomer polymer and existing resin and glass materials, thereby forming a high-cost-effective optical system that can take into account both achromatism and aberration correction functions. Specifically,

[0014] The present invention provides an optical system, which includes at least two lenses;

[0015] Among them, the material of at least one lens is a methacrylate copolymer or a methacrylate monomer polymer;

[0016] Among them, in the optical system, the Abbe number of the lens with the maximum positive refractive power is Vdmax, the Abbe number of the lens with the minimum Abbe number is Vdmin, and Vdmax - Vdmin ≧ 18.

[0017] Furthermore, in the optical system, when the material of the lens with the maximum positive refractive power is glass, the Abbe number Vdmin of the lens with the minimum Abbe number satisfies Vdmin ≤ 52.

[0018] Even further, in the optical system, when the materials of all the lenses are resins, the Abbe number Vdmin of the lens with the minimum Abbe number satisfies Vdmin ≤ 36.

[0019] Even further, the optical system further includes at least another lens whose material is a polycarbonate-based or polyester fiber-based copolymer.

[0020] Even further, the optical system further includes at least another lens whose material is glass.

[0021] Even further, the lens includes an optical working surface; the shape of the optical working surface is spherical, planar, or aspherical.

[0022] Even further, the lens includes an optical working surface; the optical working surface is a refractive surface, a reflective surface, or a diffractive surface.

[0023] Even further, the methacrylate-based monomer polymer is formed by polymerizing one methacrylate-based monomer component; the methacrylate-based copolymer is formed by copolymerizing two or more different methacrylate-based monomer components;

[0024] Among them, the methacrylate-based monomer component is selected from the following monomer components:

[0025] Phenyl polymethacrylate, benzyl methacrylate, methyl methacrylate (MMA), isobornyl methacrylate (IBX), cyclohexyl methacrylate, ethyl methacrylate, isopropyl methacrylate, n-propyl methacrylate, tert-butyl methacrylate, 2-hydroxyethyl methacrylate, 2-phenoxyethyl methacrylate, 2-(n-butoxyethyl) methacrylate, glycidyl methacrylate, 2-methylglycidyl methacrylate, and 2,2,3,4,4,5,5-octafluoropentyl methacrylate (8FM), 2,2,2-trifluoroethyl methacrylate, 2,2,3,3-tetrafluoropropyl methacrylate, 2,2,3,3-pentafluoropropyl methacrylate, 1-trifluoromethyl-2,2,2-trifluoroethyl (meth)acrylate, fluorinated alkyl esters such as 2,2,3,4,4-hexafluorobutyl (meth)acrylate, 2,2,2-trifluoroethyl methacrylate, 2,2,3,3-tetrafluoropropyl methacrylate, 2,2,3,3-pentafluoropropyl methacrylate, 1-trifluoromethyl-2,2,2-trifluoroethyl methacrylate, fluorinated alkyl methacrylates such as 2,2,3,4,4,4-(meth)acrylate hexafluorobutyl, tricyclo[5.2.1.02,6]decyl methacrylate, norbornene methacrylate, phenethyl methacrylate.

[0026] Furthermore, when the lens material is a polymethacrylate monomer polymer, the polymethacrylate monomer component is selected from phenyl polymethacrylate or phenethyl methacrylate.

[0027] Furthermore, the refractive index and Abbe number of the optical system are adjusted by adjusting the polymethacrylate monomer component of the polymethacrylate monomer polymer or the polymethacrylate copolymer.

[0028] Compared with the prior art, the beneficial technical effects of the technical solution of the present invention are as follows: 1. The refractive index and Abbe number of the optical system can be flexibly adjusted by adjusting the polymethacrylate monomer component of the polymethacrylate monomer polymer or the polymethacrylate copolymer, and the applicable fields are wide; 2. The lens can simultaneously achieve the functions of achromatism and aberration correction, and improve the optical performance; 3. The material cost is reduced, which is conducive to popularization. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 It shows a schematic distribution diagram on the refractive index-Abbe number graph of the polymer obtained by polymerizing polymethacrylate monomers.

[0030] Figure 2 It is a schematic distribution diagram on the refractive index-Abbe number graph of existing high-dispersion, low-dispersion resins and new medium-low-dispersion resins.

[0031] Figures 3-1 to 3-5 They are the lens group structure diagram, astigmatism diagram, distortion diagram, spherical aberration diagram, and longitudinal chromatic aberration diagram of Example 1 in sequence.

[0032] Figures 4-1 to 4-5 They are the lens group structure diagram, astigmatism diagram, distortion diagram, spherical aberration diagram, and longitudinal chromatic aberration diagram of Example 2 in sequence.

[0033] Figures 5-1 to 5-5 They are the lens group structure diagram, astigmatism diagram, distortion diagram, spherical aberration diagram, and longitudinal chromatic aberration diagram of Example 3 in sequence.

[0034] Figures 6-1 to 6-5 They are the lens group structure diagram, astigmatism diagram, distortion diagram, spherical aberration diagram, and longitudinal chromatic aberration diagram of Example 4 in sequence.

[0035] Figures 7-1 to 7-5 They are the lens group structure diagram, astigmatism diagram, distortion diagram, spherical aberration diagram, and longitudinal chromatic aberration diagram of Example 5 in sequence.

[0036] Figure 8 It is a schematic diagram of the spherical aberration and coma distributions of a doublet lens made of a polymethyl methacrylate copolymer material when completely achromatic.

[0037] Figure 9 It is a schematic diagram of the spherical aberration and coma distributions of a doublet lens made of a polymethyl methacrylate copolymer material when not completely achromatic.

[0038] Figure 10 It is a schematic diagram of the spherical aberration and coma distributions of a doublet lens made of a combination of a polymethyl methacrylate copolymer material and a low Abbe existing resin lens when completely achromatic.

[0039]

Symbol Explanation

[0040] L1, L2, L3: Lenses Detailed Implementation Manner

[0041] In the description of the following specific embodiments, in order to clearly show the methods of the present invention, modifiers such as "about" and "approximately" that appear before numerals in this text generally include this number, and their specific meanings should be understood in combination with the context. In the case of being described as "optical element" or "lens" or "lens blank", it refers to each unit that constitutes an optical system or a lens, which is distinguished from the "optical system" or "lens" formed by combining them. An "optical system" includes a "lens", and an "optical element" includes a "lens" or a "lens blank". A lens can be composed of a single piece or a combination of two or more lenses. "The refractive index and Abbe number can be customized", which does not mean that the refractive index or Abbe number of a formed lens can be arbitrarily customized, but in the design stage, the refractive index and Abbe number parameter values of the lens are customized according to the specification requirements, and the monomer components are proportionally combined according to these parameter values, so as to form the required copolymer material and its optical element. A material formed by polymerizing one monomer is called a monomer polymer, and the refractive index and Abbe number of a monomer polymer are constant values. A material formed by polymerizing two or more monomers is called a copolymer, and the refractive index and Abbe number of the copolymer material are different from those of each monomer polymer, and the change in the proportion of each monomer component in the copolymer will affect the values of the refractive index and Abbe number of the finally formed copolymer material. Both monomer polymers and copolymers can be called resin materials. The so-called "the material has a certain heat resistance" in the present invention means that the glass transition temperature Tg of the material is ≥ 105 °C.

[0042] Preparation and parameter determination of polymethacrylate-based monomer polymers:

[0043] 1) Preparation of methyl methacrylate monomer polymer (PMMA)

[0044] In methyl methacrylate (manufactured by Mitsubishi Chemical Corporation), 0.5 parts by weight of an initiator, that is, benzoyl peroxide (BPO, Benzoylperoxide), was added, and then 0.05 parts by weight of n-dodecyl mercaptan (n-DM) was added as a chain transfer agent. After benzoyl peroxide was completely dissolved, it was made to flow into the recess of a 10 × 10 × 5 mm mold, and thermal polymerization was carried out in a dryer at 50 °C for 5 hours to obtain a transparent resin plate composed of 10 × 10 × 5 mm PMMA. After measuring the refractive index (Nf, Nd, Nc) of this resin plate at 20 °C, the Abbe number νd and Ai were calculated. The refractive index was measured using the "Multi-wavelength Abbe refractometer DR-M2" manufactured by Atago Co., Ltd. The refractive index (Nd) and Abbe number (νd) are as Figure 1 shown in Table 1.

[0045] 2) Preparation of benzyl methacrylate monomer polymer (PBzMA)

[0046] A transparent resin plate made of PBzMA was obtained by using benzyl methacrylate (manufactured by Mitsubishi Chemical Corporation) instead of methyl methacrylate and adopting the same preparation method as in 1) above.

[0047] 3) Preparation of phenyl methacrylate monomer polymer (PPhMA)

[0048] A transparent resin plate made of PPhMA was obtained by using phenyl methacrylate (manufactured by Mitsubishi Chemical Corporation) instead of methyl methacrylate and adopting the same preparation method as in 1) above.

[0049] 4) Preparation of isobornyl methacrylate monomer polymer (PIBX)

[0050] A transparent resin plate made of PIBX was obtained by using isobornyl methacrylate (manufactured by Mitsubishi Chemical Corporation) instead of methyl methacrylate and adopting the same preparation method as in 1) above.

[0051] 5) Preparation of cyclohexyl methacrylate monomer polymer (PCHMA)

[0052] A transparent resin plate made of PCHMA was obtained by using cyclohexyl methacrylate (manufactured by Mitsubishi Chemical Corporation) instead of methyl methacrylate and adopting the same preparation method as in 1) above.

[0053] 6) Preparation of 2,2,3,3,4,4,5,5-octafluoropentyl methacrylate monomer polymer (P8FM)

[0054] A transparent resin plate made of P8FM was obtained by using 2,2,3,3,4,4,5,5-octafluoropentyl methacrylate copolymer (manufactured by Osaka Organic Chemical Industry Co., Ltd.) instead of methyl methacrylate and adopting the same preparation method as in 1) above.

[0055] 7) Preparation of tricyclo[5.2.1.02,6]dec-8-yl methacrylate monomer polymer (PTDMA)

[0056] A transparent resin plate made of PTDMA was obtained by using tricyclo[5.2.1.02,6]dec-8-yl methacrylate (manufactured by Hitachi Chemical Co., Ltd.) instead of methyl methacrylate and adopting the same preparation method as in 1) above.

[0057] 8) Preparation of phenethyl methacrylate monomer polymer (PPEMA)

[0058] (1) Synthesis of phenethyl methacrylate

[0059] A magnetic stir bar, methacrylic acid (34.4 mL, 406 mmol), 2-phenylethanol (27.9 mL, 350 mmol), p-methoxyphenol (177 mg, 1.42 mmol) as a polymerization inhibitor, and hexane (100 mL) as a solvent were added to a 200 mL three-necked flask, and the mixture was stirred for 1 hour while being cooled with ice. At this time, methanesulfonic acid (1.89 mL, 29.1 mmol) was added dropwise as a catalyst.

[0060] Next, the reaction was carried out by stirring at 100 - 110 °C for 3 hours. After the reaction, hexane was added.

[0061] Next, it was neutralized with an aqueous sodium hydroxide solution (10%) and extracted with ether.

[0062] Furthermore, it was washed with brine, the organic layer was dried with anhydrous sodium hydroxide, and the solvent was distilled off under reduced pressure.

[0063] Thus, 40.9 g of a pale yellow liquid was obtained. The product was phenethyl methacrylate. The identification of the product was carried out by NMR (1H, 13C) measurement (JEOL, FT-NNMRSpectrometer, JNM-GSX270).

[0064] (2) Preparation of phenethyl methacrylate monomer polymer (PPEMA)

[0065] Except for using the phenethyl methacrylate obtained in the above step (1) instead of methyl methacrylate, a transparent resin plate composed of PPEMA was obtained by the same preparation method as in the above 1).

[0066] As shown in Table 1, the names, corresponding monomer symbols, refractive indices, Abbe numbers, and the i-th order aspheric coefficients of the above various polymethacrylate monomer polymers are listed. As Figure 1 shown is the position of the monomer polymers listed in Table 1 in the refractive index - Abbe number coordinate system. The monomer copolymers show a distribution of discrete points in the refractive index - Abbe number coordinate system.

[0067] Materials copolymerized from any two or more than three monomers in different mixing ratios can form different refractive indices and Abbe numbers within a certain range. For example, a planar distribution can be formed in the refractive index - Abbe number coordinate system. Specifically, as Figure 2 shown, the range included by the dashed line of the third type of methacrylate copolymer material is a planar distribution rather than a point distribution, and the range of the refractive index and Abbe number of the material is expanded compared to the methacrylate monomer polymer.

[0068]

[0069] Table 1

[0070] Table 1 shows the monomer polymers of the reference examples, their symbols, refractive indices, and Abbe numbers

[0071] As shown in Table 1 and Figure 1 Representative methacrylate monomers are shown. In addition, there are other types of methacrylate monomers, including but not limited to: phenyl polymethacrylate, benzyl methacrylate, methyl methacrylate (MMA), isobornyl methacrylate (IBX), cyclohexyl methacrylate, ethyl methacrylate, isopropyl methacrylate, n-propyl methacrylate, tert-butyl methacrylate, 2-hydroxyethyl methacrylate, 2-phenoxyethyl methacrylate, 2-(n-butoxyethyl) methacrylate, glycidyl methacrylate, 2-methylglycidyl methacrylate, 2,2,3,4,4,5,5-octafluoropentyl methacrylate (8FM), 2,2,2-trifluoroethyl methacrylate, 2,2,3,3-tetrafluoropropyl methacrylate, 2,2,3,3-pentafluoropropyl methacrylate, 1-trifluoromethyl-2,2,2-trifluoroethyl (meth)acrylate, fluorinated alkyl esters such as 2,2,3,4,4-hexafluorobutyl (meth)acrylate, 2,2,2-trifluoroethyl methacrylate, 2,2,3,3-tetrafluoropropyl methacrylate, 2,2,3,3-pentafluoropropyl methacrylate, 1-trifluoromethyl-2,2,2-trifluoroethyl methacrylate, 2,2,3,4,4,4-(meth)acrylate hexafluorobutyl methacrylate and other fluorinated alkyl methacrylates; tricyclo[5.2.1.0 2,6 decyl methacrylate, norbornene methacrylate, phenethyl methacrylate, etc.

[0072] It can be selected from the above-mentioned various methacrylate monomers and can be polymerized alone, or copolymerized in pairs, or copolymerized in free combination of three or more. Therefore, according to the design requirements, a methacrylate copolymer optical material with specific refractive index and Abbe number can be customized.

[0073] The following will illustrate the beneficial technical effects that can be achieved by an optical system (lens group) formed by combining a methacrylate copolymer and other materials, including: the lens simultaneously achieving the functions of achromatism and aberration correction, reducing material costs, and ultimately improving optical performance.

[0074] First, the requirements for the Abbe number difference of the optical material for lens achromatism are explained at the theoretical level. For example, for a doublet lens to correct longitudinal chromatic aberration, the positive and negative chromatic aberrations of the positive and negative lenses need to be compensated for each other. The positive lens generates negative chromatic aberration, and the negative lens generates positive chromatic aberration, and the two cancel each other out. The refractive powers of the positive and negative lenses at this time are as follows:

[0075]

[0076] Wherein, Φ1 and Φ2 are the refractive powers of the lenses, V1 and V2 are the Abbe numbers of the positive and negative lenses respectively, and Φ is the refractive power of the lens.

[0077] As shown in formula (a), when the difference between V1 - V2 is large or small, the positive and negative lenses can eliminate the axial chromatic aberration. The difference is that the refractive powers Φ1 and Φ2 of the positive and negative lenses will change accordingly, resulting in the change of monochromatic aberrations such as spherical aberration and coma of the lens, which affects the optical performance of the lens. When Φ1 and Φ2 are large, the monochromatic aberrations such as spherical aberration are large. At this time, in order to preferentially correct the monochromatic aberration and improve the optical performance, a method of leaving a certain amount of axial chromatic aberration is often used to obtain a smaller extreme value of correcting aberrations such as spherical aberration and coma to meet the optical performance of the monochromatic aberration. However, the disadvantage of this is that it will cause the remaining axial chromatic aberration, which is not conducive to the optical system with high optical performance that requires simultaneous achromatism and correction of monochromatic aberration.

[0078] As shown in formula (a), when the difference between V1 - V2 is large, the positive and negative lenses can not only completely or preferably eliminate the axial chromatic aberration, but also the refractive powers Φ1 and Φ2 of the positive and negative lenses are small, and the extreme values of monochromatic aberrations such as spherical aberration and coma are also small. Therefore, the remaining chromatic aberration is also small, which is beneficial to improving the optical performance of the optical system.

[0079] When performing achromatism on the structure of a separated lens with a gap between lenses such as a mobile phone lens, the positive and negative chromatic aberrations of the positive and negative lenses also need to be compensated for each other. The refractive power of the lens at this time has the following formula:

[0080]

[0081] Wherein, d is the interval between the positive and negative lenses, and f1 is the focal length of the positive lens.

[0082] Regarding (1 - k), since the mobile phone lens requires a small volume, d is preferably taken as a small value. And the first lens is a positive lens. Since f1 > 0 and cannot be too small, it should be taken larger. Therefore, generally d is smaller than f1, so 0 < k < 1, and then 0 < (1 - k) < 1. Therefore, to make the first lens a positive lens, the difference between V1 and V2 in formula (b) should be larger than the difference in formula (a) to make Φ1 positive and prevent the refractive powers Φ1 and Φ2 of the lenses from being too large.

[0083] When d = 0, k = 0, which is consistent with the refractive power formulas of the positive and negative lenses of a doublet lens at this time. It can be seen that for a combined lens of a cemented lens and a separated lens, the larger the difference between V1 and V2 of the positive and negative lenses, the better. When it is a lens composed of multiple lenses, the difference between V1 and V2 can be appropriately dispersed among multiple positive and negative lenses, but the difference between V1 and V2 between the two lenses that play the main refracting role still needs to reach a certain value or more. According to experience, the difference between the Abbe number Vdmax of the lens with the largest positive refractive power and the Abbe number Vdmin of the lens with the smallest Abbe number among all the lenses can be approximately used, which is also effective.

[0084] Among them, in the present invention, the definition of Vdmax is: in a lens (optical system) composed of multiple lenses, the Abbe number of the lens with the largest positive refractive power is Vdmax;

[0085] The definition of Vdmin is: in a lens (optical system) composed of multiple lenses, the Abbe number of the lens with the smallest Abbe number is Vdmin.

[0086] The above are the theoretical and empirical results of eliminating axial chromatic aberration for paraxial spherical surfaces. In an optical system with aspherical lenses such as a mobile phone, the Abbe number does not always need to be strictly corrected for chromatic aberration according to the above formulas for paraxial positive and negative lenses. For example, sometimes the Abbe number of a paraxial positive focal length lens can be smaller than that of a paraxial negative focal length lens. Therefore, it is necessary to judge whether the overall effect of the aspherical lens on the light beam is a diverging effect or a converging effect, and accordingly correct for chromatic aberration, and accordingly determine the material combination and corresponding Abbe number that satisfy the difference between Vdmax and Vdmin.

[0087] Secondly, combined with Figure 2 explain the characteristics of existing optical resins and polymethacrylate-based resin materials, their complementarity of Abbe coefficients, and the benefits for correcting chromatic aberration.

[0088] As Figure 2 shown, the existing optical resin materials are respectively the high-dispersion and low-Abbe materials of 1) located in the upper right of the figure, such as the existing EP / OKP / SP / PC and other series of materials; and the materials of 2) with low dispersion and high Abbe located in the Figure 2 lower left, such as the existing Apel / Zeonex / Arton and other series of materials. These existing resins have specific models according to different refractive indices and Abbe numbers. In the refractive index and Abbe number diagram, one model corresponds to one point, showing a characteristic of discrete dot distribution in the figure.

[0089] As Figure 1 and Figure 2 shown. Each polymethacrylate monomer polymer is similar to each model of the above existing materials and also has corresponding refractive indices and Abbe coefficients. InFigure 1 In the refractive index and Abbe number diagram, each point corresponds one-to-one, so in Figure 1 it also shows a discrete dot distribution.

[0090] As Figure 2 shown, different from existing optical resins, polymethacrylate copolymers can form methacrylate copolymers with various different refractive indices and Abbe numbers within the range of 3) through the combined ratio of different monomers. Therefore, the range of 3) is a roughly planar region rather than discrete distribution points. Based on this characteristic, the degree of freedom in material selection can be expanded within the Abbe number range of this 3) region.

[0091] Since polymethacrylate polymers and their copolymer materials are a series of materials including medium Abbe number and high Abbe number. As Figure 2 shown, the area in the refractive index and Abbe number diagram is larger than the area occupied by the existing optical resins with high Abbe numbers in region 2), and basically fully covers the low-dispersion existing optical resins in region 2). It has a higher Abbe number (such as 57) than the existing low-dispersion resins, and an intermediate Abbe number (such as 38 - 50) not present in the resins in region 2). Therefore, whether in terms of material cost or performance indicators, the methacrylate polymers and their copolymers can replace the existing optical resin materials with low dispersion and high Abbe numbers in region 2).

[0092] However, if purely using polymethacrylate copolymer materials for an achromatic lens, due to the absence of low Abbe values, the lowest Abbe value only reaches the medium dispersion Vdmid. When Vdmid is not small enough, the difference between Vdmax - Vdmid is not large enough, and the realization of the functions of simultaneously correcting spherical aberration and chromatic aberration of the lens will be limited.

[0093] For example, as Figure 8 , 9 , and 10 all show double-gauss lenses composed of positive and negative lenses both using polymethacrylate polymer materials. Among them, the vertical axis is the spherical aberration and coma values, and the horizontal axis is the magnitude of the R value. As Figure 8 shown, the Abbe numbers of the two lenses are V1 = 54, V2 = 48.8, and V1 - V2 = 5.2 respectively. When the position chromatic aberration residue of this lens is zero, that is, when it is completely achromatic, the refractive powers of the positive and negative lenses are Φ1 = 10.385 and Φ2 = -9.385 respectively, both of which are relatively large. Thus, as Figure 8 shown, the extreme value of spherical aberration is large and there is no intersection point for coma, and spherical aberration and coma cannot be corrected simultaneously. Therefore, when this lens is completely achromatic for position chromatic aberration, its optical performance is not good.

[0094] As Figure 9 shown, when Figure 8When the residual amount of the longitudinal chromatic aberration coefficient of the doublet lens is set to 0.0235 (when the focal length f = 4.86 mm, the longitudinal chromatic aberration is about 110 microns), and the materials of the lenses remain unchanged, the refractive powers of the two lenses are Φ1 = -1.524 and Φ2 = 2.524 respectively, which are relatively small. As Figure 9 shown, at this time, the minimum value of spherical aberration and coma have an intersection, and the spherical aberration is small. Therefore, when the lens does not completely correct the longitudinal chromatic aberration (i.e., there is a residual longitudinal chromatic aberration), the performance of monochromatic aberrations such as spherical aberration is good. However, as described above, Figure 8 and Figure 9 the doublet lens has the disadvantage that it cannot simultaneously achieve the correction of chromatic aberration and monochromatic aberration due to the small difference between V1 - V2.

[0095] Therefore, as described above, the achromatic lenses that all use polymethacrylate copolymers can achieve a certain degree of chromatic aberration correction and aberration correction due to the small difference between V1 - V2. However, it is not conducive to the achromatic aberration of lenses that require high performance.

[0096] Patent Documents 1 (CN202710832U) and 2 (CN1790086A) simply use existing optical resins, which cannot well reduce the material cost, and the Abbe number of the materials lacks intermediate values, which is not conducive to the compensation of chromatic aberration and aberration for lenses other than those with the maximum and minimum Abbe numbers that require intermediate Abbe numbers.

[0097] As Figure 2 shown, the refractive indices and Abbe numbers of the polymethacrylate polymers and copolymers in region 3) and the existing optical resins with high dispersion and low Abbe in region 1) do not overlap with each other in Figure 2 and show complementarity. The two can just span the entire region of the Abbe number coordinate in Figure 2 , that is, the general range of refractive index from 1.45 to 1.7 and Abbe number from 17 to 60. That is, within this range, the combination of the methacrylate-based polymer or copolymer material in region 3) and the material such as polycarbonate-based or polyester fiber-based material in region 1) has a larger Vdmax - Vdmin range compared to the material combination composed of existing optical resin materials. And due to the existence of the medium dispersion Abbe number Vdmid of this new resin material, it can make up for the Abbe number blind area therein, which is beneficial for fine-tuning the optical performance. Therefore, the combination of the high-dispersion polycarbonate-based or polyester fiber-based materials in region 1) and the low-dispersion methacrylate-based polymer or copolymer materials in region 3) has obvious beneficial effects on expanding the difference between Vdmax - Vdmin and simultaneously realizing the functions of chromatic aberration correction and aberration correction compared to the combination of existing optical resin materials. In addition, glass has a larger range of high Abbe numbers. Therefore, the combination of polymethacrylate polymers and copolymers with glass can also expand the difference between Vdmax - Vdmin.

[0098] Therefore, based on the above theory, calculation results, and experimental test results, the conclusion drawn by the present invention is that although there will be differences in achromatism and aberration correction according to different specific optical structures and performance requirements, for a pair of lenses with the maximum positive refractive power in an achromatic lens with a methacrylate copolymer lens, the difference Vdmax - Vdmin between the Abbe number Vdmax of the lens and the lens with the minimum Abbe number Vdmin should not be too small, and a specific range should be determined, that is, at least |Vdmax - Vdmin| > 18. Preferably, Vdmax - Vdmin > 30. When the difference |Vdmax - Vdmin| is above this certain range, it is beneficial for simultaneously achieving the functions of achromatism and correcting monochromatic aberration and improving the overall optical performance of the lens.

[0099] In summary, if existing low-Abbe number resin materials such as EP or other materials such as glass are combined with different materials such as high-Abbe number polymethacrylate copolymers and polymethacrylate polymers; or high-Abbe number glass is combined with medium-high Abbe number polymethacrylate resins, the available Abbe number range in the lens can be expanded, and expanding the difference range between the Abbe number of the lens with the maximum positive refractive power and the minimum Abbe number (Vdmax - Vdmin) in the lens is beneficial for achromatism and aberration correction, thereby comprehensively improving the cost performance of the optical system in terms of low cost, achromatism, and aberration correction.

[0100] As Figure 10 shown, the lens L2 of the doublet lens of Figure 8 and Figure 9 is replaced with EP10000, a low-Abbe material with an Abbe number lower than that of the polymethacrylate polymer material, that is, V2 = 18.1, V1 - V2 = 54 - 18.1 = 35.9. The difference Vdmax - Vdmin is expanded compared to the lens of Figure 8 and Figure 9 shown. As Figure 10 shown, at this time, even when the lateral chromatic aberration residue of the lens is zero, that is, when completely achromatic, the refractive powers of the positive and negative lenses are Φ1 = 1.504 and Φ2 = -0.504 respectively, both of which are relatively small. Therefore, as Figure 10 shown, the extreme value of spherical aberration and coma intersect, and the spherical aberration is small. Therefore, for this lens, an optimal solution can be found to completely eliminate lateral chromatic aberration while also correcting monochromatic aberrations such as spherical aberration. This improves the disadvantage of the lens shown in Figure 8 , 9 that it cannot simultaneously take into account the correction of lateral chromatic aberration and monochromatic aberration. The optical performance of aberrations such as lateral chromatic aberration and spherical aberration and coma is improved.

[0101] The following separately takes an aspherical mobile phone lens with three lenses as an example, referring to the embodiment of the existing patent document 2, changes the lens material, and at the same time makes fine adjustments to the optical structure, while the basic lens structure remains unchanged. That is, the existing materials of some or all of the lenses in the embodiment of the existing patent document 2 are respectively changed to the same type of polymers, copolymer resins, or other materials with the same or different Abbe numbers as those of the polymethacrylate-based polymers or copolymers according to different embodiments.

[0102] The aspherical equation used in the embodiments of the present invention is also the same as that in the above-mentioned patent document 2. k represents the conic coefficient in the aspherical curve equation, and A1 - A16 represent the aspherical coefficients of the 1st - 16th order of each surface. The following is the description of the embodiments of the present invention.

[0103] The aspherical equation of the embodiment of the present invention adopts an even-order aspherical equation, specifically as follows:

[0104]

[0105] Among them,

[0106] X: The point on the aspherical surface at a distance Y from the optical axis, and its relative height with respect to the vertex tangent plane on the optical axis that is tangent to the aspherical surface;

[0107] Y: The distance between the point on the aspherical curve and the optical axis;

[0108] R: The radius of curvature;

[0109] k: The conic coefficient;

[0110] Ai: The aspherical coefficient of the i-th order.

[0111]

Embodiment 1

[0112] As shown in the table of Embodiment 1, Embodiment 1 is a mobile phone lens structure composed of three lenses that is the same as that of Reference 2. First, referring to Embodiment 2 of Patent Document 2, when the visible light spectra are F, d, and c, Embodiment 2 of Patent Document 2 all uses existing optical resins, and the Vdmax - Vdmin is more than 25, the residual amount of longitudinal chromatic aberration is about 69.55 microns, and the lateral chromatic aberration is about 2.5 microns.

[0113] The materials of the three lenses in Embodiment 1 of the present invention are different from those in Patent Document 2, and are all formed by polymerizing methacrylate monomers. Among them, the first lens L1 is a polymer of phenethyl methacrylate monomer (PPEMA), the second lens L2 is a polymer of phenyl polymethacrylate monomer (PPhMa), and the third lens L3 is a polymer of phenethyl methacrylate monomer (PPEMA). The lenses with the largest Abbe number are L1 and L3 with Vdmax = 54, and the lens with the smallest Abbe number is L2 with Vdmin = 36, and Vdmax - Vdmin = 54 - 36 = 18. The parameters of the lens group in this Embodiment 1 are: focal length f = 4.86, aperture number Fno = 2.88, and image height Y = 2.8.

[0114] Since the Abbe number difference Vdmax - Vdmin in this Embodiment 1 is less than half of that in Embodiment 1 of Reference Patent Document 2. As Figure 3-4 shown in the spherical aberration diagram, the longitudinal chromatic aberration on the optical axis is about 65 microns, and the lateral chromatic aberration is about 2.2 microns, which is smaller than that in Embodiment 2 of Reference Patent Document 2 using existing optical resins. Therefore, the achromatic results of the lens groups in both this Embodiment 1 and Patent Document 2 are comparable. Other aberrations such as spherical aberration, astigmatism, field curvature, and distortion are also comparable.

[0115] Therefore, in this embodiment, the minimum value of Vdmax - Vdmin is set to Vdmax - Vdmin = 54 - 36 = 18, referring to the result of the residual longitudinal chromatic aberration in Embodiment 2 of the existing Patent Document 2, and a comparable residual longitudinal chromatic aberration can be obtained. At the same time, as Figures 3-2 to 3-5 shown, the aberration values such as spherical aberration are also the same. Therefore, like Patent Document 2, while correcting chromatic aberration, the correction of monochromatic aberration is also taken into account. Therefore, Vdmax - Vdmin = 54 - 36 = 18 is equivalent and feasible compared with Reference Patent Document 2.

[0116] In addition, since the material costs of Embodiments 1 and 2 in Patent Document 2 both use existing optical resins or glass and material mixtures. For example, in Embodiment 1 of Patent Document 2, the first lens uses optical glass, the second lens uses polycarbonate (PC), and the third lens uses ARTON from JST, resulting in a relatively high cost. Therefore, relatively speaking, the comprehensive material cost of this Embodiment 1 has been reduced.

[0117] Therefore, the cost performance of the material combination in this Embodiment 1 has been improved to a certain extent compared with that in Embodiment 1 of Patent Document 2.

[0118]

[0119] Table 2 Lens Parameter Table of Embodiment 1

[0120]

[0121] Table 3 Aspherical Coefficient Table of the Lenses in Example 1

[0122]

Example 2

[0123] As shown in the following table of Example 2, the lens structure of the mobile phone lens in Example 2 of the present invention is composed of 3 lenses that are the same as those in Reference 2. Different from Example 1 of the present invention, the materials of the 3 lenses are as follows: the first lens is glass FK5, and the second and third lenses are both isobornyl methacrylate monomer polymers (PIBX). The parameters of the lens group in this Example 2 are: focal length f = 4.86, f-number Fno = 2.88, image height Y = 2.8

[0124] Among the above 3 lenses, the lens with the largest positive refractive power is lens 1, and its Abbe number Vdmax is Vdmax = 70.4. The lens with the smallest Abbe number is lens 2, Vdmin = 52, and Vdmax - Vdmin = 70.4 - 52 = 18.4

[0125] As Figure 4-4 can be seen from the spherical aberration diagram shown, the longitudinal chromatic aberration at the optical axis is about 64 microns, and the lateral chromatic aberration is about 2.7 microns, which is comparable to the achromatic aberration result of the lens of the resin lens in Example 2 using the existing optical resin in Reference Patent Document 2. Other aberrations such as astigmatism, field curvature, and distortion are also comparable

[0126] Therefore, in this embodiment, the difference between Vdmax and Vdmin is set to Vdmax - Vdmin = 70.4 - 52 = 18.4, referring to the achromatic aberration result of the embodiment in the existing patent document 2. A residual longitudinal chromatic aberration amount comparable to that of patent document 2 can be obtained. At the same time, as Figures 4-2 to 4-4 shown, aberration values such as spherical aberration are also the same. Therefore, like patent document 2, while correcting achromatic aberration, aberration correction is also taken into account. Therefore, Vdmax - Vdmin = 70.4 - 52 = 18.4 is basically equivalent to and feasible compared with Reference Patent 2

[0127] Since the material cost of Example 1 in Patent Document 2 uses a mixture of existing optical resin and glass, such as the first lens in Example 1 of Patent Document 2 uses optical glass, the second lens uses polycarbonate (PC), and the third lens uses ARTON of JST Corporation, the cost is relatively high. Therefore, relatively speaking, the material cost of isobornyl methacrylate monomer polymer (PIBX) in this Example 2 is lower, and the comprehensive material cost has been reduced

[0128] Therefore, the cost performance of the material combination in this Example 2 has been improved to a certain extent compared with that of Example 1 in Patent Document 2

[0129]

[0130] Table 4 Lens Parameter Table of Example 2

[0131]

[0132] Table 5 Aspherical Coefficient Table of the Lens in Example 2

[0133]

Example 3

[0134] As shown in the table of Example 3, Example 3 is a mobile phone lens composed of three lenses. The specifications are the same as those of Example 1 of the present invention and Patent Document 2. Different from Example 1 of the present invention, the materials of the three lenses are as follows: the first lens L1 is a methacrylate copolymer with adjustable refractive index and Abbe number, the second lens L2 is a phenyl polymethacrylate monomer polymer (PPhMa), and the third lens L3 is also a methacrylate copolymer with adjustable refractive index and Abbe number.

[0135] Among the three lenses in this Example 3, the lens with the largest positive refractive power is the first lens L1, and its Abbe number Vdmax = 57; the lens with the smallest Abbe number is the second lens L2, and its Abbe number Vdmin = 36, Vdmax - Vdmin = 57 - 36 = 21, which is slightly larger than that of Example 1 and is close to the example using existing optical resins in Reference Patent Document 2. As Figure 5-4 shown, it can be seen from the spherical aberration diagram that the residual amount of axial chromatic aberration of the optical axis is about 58.5 microns, the lateral chromatic aberration is about 1.9 microns, and other aberrations such as astigmatism, field curvature, and distortion are also similar to those in Example 1 of Reference Document 2. The parameters of the lens group in this Example 3 are: focal length f = 4.86, f-number Fno = 2.88, and image height Y = 2.8.

[0136] Therefore, after the above material change, on the premise of the same structural specifications, the achromatic aberration and aberration correction performance of this Example 3 are slightly better than those in Reference Document 2 but basically equivalent, indicating that this is related to the insufficient increase in the difference of Vdmax - Vdmin. However, overall, the material cost of this Example 3 has decreased. Therefore, the achromatic aberration function and material cost performance of the material combination in this Example 3 are better than those in Patent Document 2.

[0137] At the same time, it can also be seen that since the first and third lenses use methacrylate copolymers, their Abbe numbers can be adjusted to 57, which is higher than that of the methacrylate monomer polymer in Example 1 of the present invention, and the difference of Vdmax - Vdmin is larger. Therefore, both the axial chromatic aberration and the lateral chromatic aberration are slightly improved. This characteristic of being able to flexibly adjust the Abbe number and refractive index according to needs is also an advantage of methacrylate copolymers compared to methacrylate monomer polymers or other optical materials.

[0138]

[0139] Lens parameter table of Example 3

[0140]

[0141] Aspherical coefficient table of the lens in Example 3

[0142]

Example 4

[0143] As shown in the table of Example 4, Example 4 is a mobile phone lens composed of three lenses. The specifications are the same as those of Example 1, Example 2 and Patent Document 2 of the present invention. Different from Example 3 of the present invention, the materials of the three lenses are as follows: the first lens L1 is a monomer polymer of phenethyl methacrylate (PPEMA), the second lens L2 is an existing special polycarbonate EP9000, and the third lens L3 is a methacrylate copolymer. Among the three lenses, the lens with the largest positive refractive power is the first lens L1, and its Abbe number Vdmax = 54; the lens with the smallest Abbe number is the second lens L2, and its Abbe number Vdmin = 19.3, Vdmax - Vdmin = 54 - 19.3 = 34.7. Since the difference in Abbe numbers between the lenses with the largest and smallest Abbe numbers in this Example 4 is greater than that in Examples 1 and 2, as Figure 6-4 shown, it can be seen from the spherical aberration diagram that the residual amount of chromatic aberration on the optical axis is about 30 microns, and the maximum magnification chromatic aberration is also smaller, about 1.5 microns. Aberrations such as astigmatism, field curvature, and distortion are similar to those in Patent Document 2 and Examples 1 and 2 of the present invention. Therefore, after the material change, on the premise of the same structural specifications, the achromatic performance of this example is greatly improved compared with Patent Document 2 and Examples 1 and 2, and the longitudinal chromatic aberration is reduced by nearly half compared with Example 3 (reduced by 28.5 microns). In addition, in this Example 4, the material replacement cost has decreased. Therefore, the performance-price ratio of the material combination in this Example 4 is better than that of the existing Patent Document 2. The parameters of the lens group in this Example 4 are: focal length f = 4.86, aperture number Fno = 2.88, and image height Y = 2.8.

[0144] Meanwhile, although Example 3 uses two methacrylate copolymers to participate in the adjustment of refractive index and Abbe number, which has one more lens for adjusting refractive index and Abbe number than this example, and the Abbe numbers of the first and third lenses are 3 higher than those of the lenses L1 and L3 in Example 4 of this example, however, the difference between Vdmax - Vdmin is much smaller than that in Example 4 of this example. This is because the lens L2 in this example uses the special polycarbonate series EP9000 with a lower Abbe number, resulting in the minimum Abbe number Vdmin = 19.3 in this example. Thus, the difference between Vdmax - Vdmin is increased from 21 in Example 3 to 34.7 in this example, an increase of nearly one-third or more. Therefore, the ability of Example 3 to balance achromatism and correct aberration is relatively weaker than that of Example 4 of this example, that is, relatively speaking, the change in Abbe number for adjusting the Abbe number within a smaller range compared to the difference between the maximum and minimum Abbe numbers is small. Therefore, the proportion of the overall achromatic performance is small.

[0145] It can be seen that compared with the prior art, Example 3 of the present invention only adjusts the difference between the maximum and minimum Abbe numbers (Vdmax - Vdmin) within a relatively small range, while Example 4 of the present invention greatly adjusts the difference between the maximum and minimum Abbe numbers (Vdmax - Vdmin). Therefore, the ability of Example 3 to balance achromatism and correct aberration is relatively weaker than that of Example 4, and the improvement in the overall achromatism and aberration correction ability of Example 4 is significantly enhanced.

[0146]

[0147] Table 8 Lens Parameter Table of Example 4

[0148]

[0149] Table 9 Aspherical Coefficient Table of Lenses in Example 4

[0150]

Example 5

[0151] As shown in the table of Example 5, Example 5 is a mobile phone lens composed of three lenses. The specifications are the same as those of Examples 1, 2, 3, 4 of the present invention and Patent Document 2. Different from Examples 1, 2, 3, and 4, the materials of the three lenses are as follows: the first lens L1 is a methacrylate copolymer, the second lens L2 is the existing special polycarbonate OKPA4, and the third lens L3 is a methacrylate copolymer. Among the three lenses, the lens with the largest positive refractive power is the first lens L1, and its Abbe number is Vdmax = 57; the lens with the smallest Abbe number is the second lens L2, and its Abbe number is Vdmin = 17, Vdmax - Vdmin = 57 - 17 = 40. Since the difference between the Abbe numbers of the lenses with the largest and smallest Abbe numbers in this example, Vdmax - Vdmin, is larger than that in Examples 1, 2, and 3, as Figure 7-4As shown, it can be seen from the spherical aberration diagram that the residual chromatic aberration of the optical axis position is only about 3 microns or less, and the maximum magnification chromatic aberration is even smaller, about 1 micron. The parameters of the lens group in Embodiment 5 are: focal length f = 4.86, aperture number Fno = 2.88, and image height Y = 2.8.

[0152] Since it is different from Embodiment 4, in Embodiment 5, the first and third lenses both use a methacrylate copolymer with adjustable refractive index and Abbe number. The Abbe number of the first lens is higher than that in Embodiment 4, while the Abbe number of the second lens uses the existing OKPA4 material with a lower Abbe number than that in Embodiment 4. Therefore, the Abbe number difference Vdmax - Vdmin is larger than that in Embodiment 4. Thus, as shown by the foregoing data, the comprehensive ability to correct chromatic aberration and monochromatic aberration is higher than that in Embodiment 4.

[0153] In addition, since the first and third lenses jointly participate in the adjustment of the refractive index and Abbe coefficient, the adjustment freedom is higher than that in Embodiments 1, 2, 3, and 4. Aberrations such as astigmatism, field curvature, and distortion are also smaller than those in Patent Document 2 and Embodiments 1, 2, 3, and 4. Therefore, after the material change, on the premise of the same structural specifications, the chromatic aberration correction performance and the function of correcting monochromatic aberration in this embodiment are better than those in Reference Patent Document 2 and Embodiments 1, 2, 3, and 4. It should be noted that the Abbe number of lens 3 in this embodiment does not have a relatively high Abbe number as in Embodiments 3 and 4, but has an intermediate Abbe value of 42. This is because the third lens is the last lens, and its parameters such as refractive index and Abbe number mainly act on the fine adjustment of the off-axis optical performance, which is beneficial to the improvement of optical performance. This is the special feature of the methacrylate copolymer material compared with existing materials such as existing optical resins. At the same time, in Embodiment 5, the material cost has decreased. Therefore, the performance - price ratio of the material combination in Embodiment 5 is more excellent than that of the existing Patent Document 2 and the foregoing Embodiments 1, 2, 3, and 4.

[0154]

[0155] Table 10 Lens Parameter Table of Embodiment 5

[0156]

[0157] Table 11 Aspherical Coefficient Table of Lenses in Embodiment 5

[0158] The various characteristic values of chromatic aberration correction for each lens of the polymethacrylate - based polymer or copolymer in the foregoing Embodiments 1, 2, 3, 4, and 5 or their combinations with other material lenses are summarized in the following table.

[0159] NO. Vdmax - Vdmin Vdmin Number of Abbe adjustable lenses Axial chromatic aberration (micrometers) Lateral chromatic aberration (micrometers) Patent Document 2 25 30 None 70 25 Example 1 18 36 None 65 2.2 Example 2 18 52 None 64 2.7 Example 3 21 36 2 59 19 Example 4 35 19.3 1 30 15 Example 5 37 17 2 3 1

[0160] Table 12 Summary Table of Resin Abbe Number Characteristics of Embodiments 1 - 5

[0161] Advantages of Embodiments 1, 2, 3, 4, and 5 of the present invention:

[0162] 1. By combining polymethacrylate copolymers or monomer polymers with existing optical materials, the material cost of the optical system is lower than that of the optical system using only existing materials, and the cost performance of the lens can be improved.

[0163] 2. Combining polymethacrylate polymers or copolymers with other optical resins or glass materials with lower or higher Abbe numbers can expand the Abbe number combination range of existing optical resin materials, which is beneficial to increasing the value of Vdmax - Vdmin, and is beneficial to the optical system to balance chromatic aberration correction and aberration correction and improve optical performance.

[0164] 3. The minimum value of Vdmax - Vdmin should not be less than 18, otherwise the residual chromatic aberration will be larger than that of the prior art;

[0165] 4. When the lens material with the largest Abbe number is glass, the Vdmin of the lens with the smallest Abbe number should not be greater than 52, otherwise it is difficult to balance chromatic aberration correction and aberration correction; when the lens materials are all resins, the Vdmin of the lens with the smallest Abbe number should not be greater than 36, otherwise it is difficult to balance chromatic aberration correction and aberration correction;

[0166] 5. A large number of polymethacrylate copolymer lenses with adjustable Abbe numbers are beneficial to chromatic aberration correction and optical performance correction.

[0167] The three-piece mobile phone lens of Embodiments 1, 2, 3, 4, and 5 described in this specification is only a preferred specific embodiment of the present invention, and is only used to illustrate the technical solution of the present invention rather than to limit the present invention. The chromatic aberration correction of the optical system using polymethacrylate resin lenses can also be applicable to various multi-piece fixed-focus or zoom lenses or other optical systems with more than two pieces.

[0168] When the lens is composed of four or more pieces, the maximum Abbe number should be calculated for the difference Vdmax - Vdmin according to the Abbe number Vdmax of the lens with the largest positive refractive power and the Abbe number Vdmin of the lens with the smallest Abbe number. It has the same effect.

[0169] All technical solutions that can be obtained by those skilled in the art through logical analysis, reasoning, or limited experiments based on the concept of the present invention should be within the scope of the present invention. In addition, the lenses in this embodiment usually use refractive even aspherical surfaces for mobile phone lenses, and other refractive spherical surfaces, flat surfaces, free-form surfaces, etc. or diffractive surfaces other than refractive surfaces, metasurface surfaces, etc. are also applicable to this optical system and its polymethacrylate monomer polymers and copolymer materials.

[0170] Industrial Applicability: The optical system using the methacrylate copolymer and its monomer polymer of the present invention can be applied to various digital lenses, such as lenses or optical systems in mobile phones, vehicles, surveillance, virtual and augmented reality, Internet of Things, notebooks, medical, aviation and other industries. In particular, it is beneficial to improve the cost performance of lenses that require both achromatism and aberration correction for various optical lenses using existing optical materials.

[0171] What is described in this specification is only the preferred specific embodiments of the present invention. The above embodiments are only used to illustrate the technical solutions of the present invention rather than to limit the present invention. Any technical solutions that can be obtained by those skilled in the art through logical analysis, reasoning or limited experiments based on the concept of the present invention should be within the scope of the present invention.

Claims

1. An optical system, characterized in that: Containing at least two lenses; Wherein, the material of at least one lens is a methacrylate copolymer or a methacrylate monomer polymer; In the optical system, the Abbe number of the lens with the maximum positive refractive power is Vdmax, the Abbe number of the lens with the minimum Abbe number is Vdmin, and Vdmax-Vdmin≧18.

2. The optical system according to claim 1, characterized in that When the material of the lens with the maximum positive refractive power is glass, the Abbe number Vdmin≦52 of the lens with the minimum Abbe number.

3. The optical system according to claim 1, characterized in that When the materials of the lenses are all resin, the Abbe number Vdmin≦36 of the lens having the minimum Abbe number.

4. The optical system according to claim 1, characterized in that The optical system further comprises at least one other lens whose material is a polycarbonate-based or polyester-based copolymer.

5. The optical system according to claim 1, characterized in that The optical system further includes at least one lens made of glass.

6. The optical system according to claim 1, characterized in that The lens comprises an optical working surface; the shape of the optical working surface is spherical, flat or aspherical.

7. The optical system according to claim 1, characterized in that The lens comprises an optical working surface; the optical working surface is a refractive surface, a reflective surface or a diffractive surface.

8. The optical system according to any one of claims 1 to 7, characterized in that The methacrylate monomer polymer is formed by polymerizing one methacrylate monomer component; the methacrylate copolymer is formed by copolymerizing two or more different methacrylate monomer components; Wherein, the methacrylate monomer component is selected from the following monomer components: Phenyl polymethacrylate, benzyl methacrylate, methyl methacrylate (MMA), isobornyl methacrylate (IBX), cyclohexyl methacrylate, ethyl methacrylate, isopropyl methacrylate, n-propyl methacrylate, tert-butyl methacrylate, 2-hydroxyethyl methacrylate, 2-phenoxyethyl methacrylate, 2-(n-butoxyethyl methacrylate), glycidyl methacrylate, 2-methylglycidyl methacrylate and 2,2,3,4,4,5,5-octafluoropentyl methacrylate (8FM), 2,2,2-trifluoroethyl methacrylate, 2,2,3,3-tetrafluoropropyl methacrylate, Fluorinated alkyl esters such as 2,2,3,3-pentafluoropropyl methacrylate, 1-trifluoromethyl-2,2,2-trifluoroethyl methacrylate, and 2,2,3,4,4-hexafluorobutyl (meth)acrylate, fluoroalkyl methacrylates such as 2,2,2-trifluoroethyl methacrylate, 2,2,3,3-tetrafluoropropyl methacrylate, 2,2,3,3-pentafluoropropyl methacrylate, 1-trifluoromethyl-2,2,2-trifluoroethyl methacrylate, and 2,2,3,4,4,4-hexafluorobutyl (meth)acrylate, tricyclo[5.2.1.02,6]decyl methacrylate, norbornene methacrylate, and phenylethyl methacrylate.

9. The optical system according to claim 8, characterized in that When the lens materials are all methacrylate monomer polymers, the methacrylate monomer components are selected from phenyl polymethacrylate or phenylethyl methacrylate.

10. The optical system according to claim 8, characterized in that The refractive index and the Abbe number of the optical system are adjusted by adjusting the methacrylate monomer component of the methacrylate monomer polymer or the methacrylate copolymer.

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