Optical systems and imaging devices and electronic equipment containing them

Abstract

This application provides an optical system and imaging devices and electronic devices including the same, belonging to the technical field of optical imaging. It includes a first, second, third, fourth, fifth, and sixth lens along the object-side to the image-side; the first lens is an aspherical refractive lens; the second lens is a superlens; the remaining lenses are all refractive lenses; all surfaces of the third to sixth lenses include at least one aspherical surface, which contains a point of inflection; the first lens has positive optical power; the object side of the first lens and the image side of the third lens are convex; the object side of the fourth lens is concave; the object-side radii of curvature of the fifth and sixth lenses are both negative; satisfying: 25°≤HFOV≤55°; 0.05mm≤d2≤2mm; |f2| / f≥10; where f is the focal length of the optical system; EPD is the entrance pupil diameter; HFOV is half of the maximum field of view; d2 is the thickness of the second lens; and f2 is the focal length of the second lens, achieving miniaturization.

Description

Technical Field

[0001] This application relates to the technical field of optical imaging, and more specifically, to optical systems and imaging devices and electronic devices including the same. Background Technology

[0002] With advancements in semiconductor manufacturing, the pixel size of image sensors continues to shrink, placing increasingly higher demands on the imaging performance of optical systems.

[0003] However, the common practice to achieve high performance in an optical system is to increase the number of lenses within the system. This inevitably leads to an increase in the size and weight of the optical system.

[0004] Therefore, miniaturization and weight reduction of optical systems while ensuring imaging quality has become an urgent problem to be solved. Summary of the Invention

[0005] To address the problem of increased size and weight of optical systems due to the increased number of lenses in existing technologies, embodiments of this application provide an optical system and an imaging device and electronic device including the same.

[0006] In a first aspect, embodiments of this application provide an optical system comprising a first lens, a second lens, a third lens, a fourth lens, a fifth lens, and a sixth lens arranged sequentially from the object side to the image side;

[0007] Wherein, the first lens is an aspherical refractive lens; the second lens is a superlens; the remaining lenses are all refractive lenses, and all surfaces of the third, fourth, fifth and sixth lenses include at least one aspherical surface, the aspherical surface containing a point of inflection;

[0008] The first lens has positive optical power, and the object-side surface of the first lens is convex; the image-side surface of the third lens is convex; the object-side surface of the fourth lens is concave; the radii of curvature of the object-side surfaces of the fifth lens and the sixth lens are both negative.

[0009] The optical system must satisfy at least the following relationship:

[0010] f / EPD<3

[0011] 25°≤HFOV≤55°

[0012] 0.05mm≤d2≤2mm

[0013] |f2| / f≥10;

[0014] Where f is the focal length of the optical system; EPD is the entrance pupil diameter of the optical system; HFOV is half of the maximum field of view of the optical system; d2 is the thickness of the second lens; and f2 is the focal length of the second lens.

[0015] Optionally, the optical system also satisfies the following relationship:

[0016] 0.35≤R 1o / f1≤0.58;

[0017] Among them, R 1o f1 is the radius of curvature of the object-side surface of the first lens; f1 is the focal length of the first lens.

[0018] Optionally, the optical system also satisfies:

[0019] (V1+V4) / 2-V3>20;

[0020] Wherein, V1 is the Abbe number of the first lens; V3 is the Abbe number of the third lens; and V4 is the Abbe number of the fourth lens.

[0021] Optionally, the optical system also satisfies:

[0022] 0.55 <ImgH / TTL<0.82;

[0023] Wherein, ImgH is the maximum imaging height of the optical system; TTL is the distance from the object-side surface of the first lens to the imaging surface of the optical system.

[0024] Optionally, the optical system further satisfies the following conditions: the image-side surface of the fourth lens is concave, and...

[0025] R 4i ×R 4o >0;

[0026] Among them, R 4o R is the radius of curvature of the object-side surface of the fourth lens; 4i The radius of curvature of the image-side surface of the fourth lens is given.

[0027] Optionally, the radius of curvature of the image-side surface of the fifth lens is less than zero.

[0028] Optionally, the optical system also satisfies:

[0029] 0.58≤f1 / f≤0.85;

[0030] Where f1 is the focal length of the first lens; and f is the focal length of the optical system.

[0031] Optionally, any one or more of the third lens, the fourth lens, the fifth lens, and the sixth lens may be aspherical refractive lenses.

[0032] Optionally, the superlens includes a substrate layer and at least one nanostructure layer disposed on one side of the substrate layer;

[0033] Wherein, any of the nanostructure layers comprises periodically arranged nanostructures;

[0034] The substrate layer and the nanostructure layer are configured to transmit radiation in the operating wavelength range of the optical system.

[0035] Optionally, the superlens comprises at least two nanostructure layers;

[0036] In this design, the nanostructures in any two adjacent nanostructure layers are arranged coaxially.

[0037] Optionally, the superlens includes at least two nanostructure layers; wherein the nanostructures in any adjacent nanostructure layers are staggered along a direction parallel to the substrate of the superlens.

[0038] Optionally, the arrangement period of the nanostructure is greater than or equal to 0.3λ. c And less than or equal to 2λ c , where λ c The wavelength is the center wavelength of the operating band of the optical system.

[0039] Optionally, the height of the nanostructure is greater than or equal to 0.3λ. c And less than or equal to 2λ c , where λ c The wavelength is the center wavelength of the operating band of the optical system.

[0040] Optionally, the material of the base layer includes any one or more of fused silica, quartz glass, crown glass, flint glass, sapphire, and alkaline glass.

[0041] Optionally, the material of the nanostructure includes any one or more of fused silica, quartz glass, crown glass, flint glass, sapphire, crystalline silicon, amorphous silicon, and hydrogenated amorphous silicon.

[0042] Optionally, the nanostructure is made of the same material as the substrate layer.

[0043] Optionally, the nanostructure and the substrate layer are made of different materials.

[0044] Optionally, the superlens further includes a filler;

[0045] The filler is placed between the nanostructures; the extinction coefficient of the filler for the operating wavelength of the optical system is less than 0.01.

[0046] Optionally, the absolute value of the difference between the refractive index of the filler and the refractive index of the nanostructure is greater than or equal to 0.5.

[0047] Optionally, the filler material includes any one or more of air, fused silica, quartz glass, crown glass, flint glass, sapphire, crystalline silicon, amorphous silicon, and hydrogenated amorphous silicon.

[0048] Optionally, the material of the filler is different from the material of the nanostructure.

[0049] Optionally, the material of the filler is different from the material of the base layer.

[0050] Optionally, the superlens further includes an anti-reflective coating;

[0051] Wherein, the antireflective film is disposed on the side of the nanostructure layer adjacent to air; and / or,

[0052] The antireflective film is disposed on the side of the substrate layer away from the nanostructure layer.

[0053] Optionally, the nanostructures are arranged periodically in the form of superstructural units;

[0054] The superstructure unit is in the shape of a close-packed pattern, and the nanostructure is disposed at the vertex and / or center of the close-packed pattern.

[0055] Optionally, the shape of the superstructure unit includes one or more combinations of sector, square, and hexagon.

[0056] Optionally, the shape of the nanostructure is a polarization-insensitive structure.

[0057] Optionally, the shape of the nanostructure includes one or more combinations of cylindrical, hollow cylindrical, circular hole, hollow circular hole, square column, square hole, hollow square column, and hollow square hole.

[0058] Optionally, the phase of the superlens also satisfies:

[0059]

[0060]

[0061]

[0062]

[0063]

[0064]

[0065]

[0066]

[0067] Where r is the distance from the center of the superlens to any nanostructure; λ is the operating wavelength of the superlens; f1 represents any phase related to the operating wavelength of the superlens; (x, y) represents the mirror coordinates of the superlens; f2 represents the focal length of the superlens; ai and bi are real coefficients.

[0068] Optionally, the operating wavelengths of the optical system include the visible light band and the near-infrared band.

[0069] Secondly, embodiments of this application also provide a method for fabricating a superlens, used to fabricate a superlens in an optical system as provided in any of the above embodiments, the method comprising:

[0070] Step S1: Deposit a structural layer material on the base layer;

[0071] Step S2: Coat the structural layer material with photoresist and expose the reference structure;

[0072] Step S3: Etch the periodically arranged nanostructures on the structural layer according to the reference structure to form the nanostructure layer;

[0073] Step S4: The filler is disposed between the nanostructures;

[0074] Step S5: Trim the surface of the filler so that the surface of the filler coincides with the surface of the nanostructure.

[0075] Optionally, the method further includes:

[0076] Step S6: Repeat steps S1 to S5 until all nanostructure layers are set.

[0077] Thirdly, embodiments of this application further provide an imaging device, the imaging device comprising:

[0078] The optical system and the photosensitive element disposed on the image plane of the optical system are provided in any of the above embodiments.

[0079] Fourthly, embodiments of this application also provide an electronic device, which includes the imaging device provided in the above embodiments.

[0080] In summary, the optical system provided in this application provides the main optical power by setting the first lens as an aspherical refractive lens, setting the second lens as a superlens, setting the remaining lenses as refractive lenses, and ensuring that at least one of the surfaces of the third to sixth lenses is aspherical. Furthermore, by employing a layout that satisfies f / EPD < 3; 25° ≤ HFOV ≤ 55°; 0.05mm ≤ d2 ≤ 2mm, the system length and weight of the six-element optical system are reduced while maintaining image quality, thus promoting miniaturization and weight reduction of the optical system.

[0081] The imaging device provided in this application uses the optical system provided in this application. Compared with traditional optical systems, the optical system has a smaller size, lighter weight, and excellent imaging quality. It is beneficial to combine the optical system with larger sensors and can also reduce the installation space occupied by the optical system in the imaging device, thereby promoting the miniaturization and weight reduction of the imaging device.

[0082] The electronic device provided in this application embodiment employs the imaging device provided in this application embodiment. Because the optical system provided in this application embodiment has a smaller size, lighter weight, and superior imaging quality compared to traditional optical systems, it facilitates the integration of the optical system with larger sensors and reduces the installation space occupied by the optical system in the imaging device and electronic device. Therefore, the electronic device provided in this application embodiment, by employing this imaging device, reduces the size and weight of the imaging device in the electronic device, promoting miniaturization and weight reduction of the electronic device. Attached Figure Description

[0083] The accompanying drawings are provided to further understand this application and are incorporated in and form a part of this specification. The drawings illustrate embodiments of this application and, together with the following description, serve to explain the principles of this application.

[0084] Figure 1 This paper shows a schematic diagram of an optional structure of the optical system provided in an embodiment of the present application;

[0085] Figure 2 This paper shows another optional structural schematic diagram of the optical system provided in the embodiments of this application;

[0086] Figure 3 This paper shows another optional structural schematic diagram of the optical system provided in the embodiments of this application;

[0087] Figure 4 This paper shows another optional structural schematic diagram of the optical system provided in the embodiments of this application;

[0088] Figure 5This paper shows another optional structural schematic diagram of the optical system provided in the embodiments of this application;

[0089] Figure 6 This paper shows another optional structural schematic diagram of the optical system provided in the embodiments of this application;

[0090] Figure 7 This paper shows another optional structural schematic diagram of the optical system provided in the embodiments of this application;

[0091] Figure 8 This paper shows another optional structural schematic diagram of the optical system provided in the embodiments of this application;

[0092] Figure 9 This paper shows another optional structural schematic diagram of the optical system provided in the embodiments of this application;

[0093] Figure 10 This paper shows another optional structural schematic diagram of the optical system provided in the embodiments of this application;

[0094] Figure 11 This illustration shows an optional structural diagram of a superlens in an optical system provided in an embodiment of this application;

[0095] Figure 12 This illustration shows an optional structural diagram of the nanostructure in the superlens provided in an embodiment of this application;

[0096] Figure 13 This illustration shows another optional structural diagram of the nanostructure in the superlens provided in this application embodiment;

[0097] Figure 14 This illustration shows a schematic diagram of an optional arrangement of nanostructures in a superlens provided in an embodiment of this application;

[0098] Figure 15 This illustration shows another optional arrangement of nanostructures in a superlens provided in an embodiment of this application;

[0099] Figure 16 This illustration shows another optional arrangement of nanostructures in a superlens provided in an embodiment of this application;

[0100] Figure 17 This illustration shows another optional structural diagram of the nanostructure in the superlens provided in this application embodiment;

[0101] Figure 18 This illustration shows another optional structural diagram of the nanostructure in the superlens provided in this application embodiment;

[0102] Figure 19This illustration shows another optional structural diagram of the nanostructure in the superlens provided in this application embodiment;

[0103] Figure 20 This illustration shows another optional structural diagram of the superlens provided in an embodiment of this application;

[0104] Figure 21 This illustration shows another optional structural diagram of the superlens provided in an embodiment of this application;

[0105] Figure 22 This illustration shows another optional structural diagram of the superlens provided in an embodiment of this application;

[0106] Figure 23 This illustration shows an optional phase diagram of a superlens provided in an embodiment of this application;

[0107] Figure 24 This illustration shows an optional transmittance diagram of the superlens provided in an embodiment of this application;

[0108] Figure 25 This illustration shows another optional phase diagram of the superlens provided in an embodiment of this application;

[0109] Figure 26 This illustration shows another optional transmittance diagram of the superlens provided in the embodiments of this application;

[0110] Figure 27 A schematic flowchart of an optional superlens fabrication method provided in an embodiment of this application is shown;

[0111] Figure 28 This illustration shows another optional flowchart of the superlens fabrication method provided in the embodiments of this application;

[0112] Figure 29 This illustration shows another optional flowchart of the superlens fabrication method provided in the embodiments of this application;

[0113] Figure 30 This illustration shows a schematic diagram of phase modulation of a second lens at different wavelengths in an optional optical system provided in an embodiment of this application;

[0114] Figure 31 An astigmatism diagram of an optional optical system provided in an embodiment of this application is shown;

[0115] Figure 32 The distortion diagram of an optional optical system provided in an embodiment of this application is shown;

[0116] Figure 33 This illustrates the broadband matching degree of a second lens in an optional optical system provided by an embodiment of this application;

[0117] Figure 34 This illustration shows a schematic diagram of phase modulation of the second lens at different wavelengths in another optional optical system provided in this application embodiment;

[0118] Figure 35 An astigmatism diagram of yet another optional optical system provided in an embodiment of this application is shown;

[0119] Figure 36 The distortion diagram of another optional optical system provided in the embodiments of this application is shown;

[0120] Figure 37 This illustrates the broadband matching degree of a second lens in an optional optical system provided by an embodiment of this application;

[0121] Figure 38 This illustration shows a schematic diagram of phase modulation of the second lens at different wavelengths in another optional optical system provided in this application embodiment;

[0122] Figure 39 An astigmatism diagram of yet another optional optical system provided in an embodiment of this application is shown;

[0123] Figure 40 The distortion diagram of another optional optical system provided in the embodiments of this application is shown;

[0124] Figure 41 This illustrates the broadband matching degree of a second lens in an optional optical system provided by an embodiment of this application;

[0125] Figure 42 This illustration shows a schematic diagram of phase modulation of the second lens at different wavelengths in another optional optical system provided in this application embodiment;

[0126] Figure 43 An astigmatism diagram of yet another optional optical system provided in an embodiment of this application is shown;

[0127] Figure 44 The distortion diagram of another optional optical system provided in the embodiments of this application is shown;

[0128] Figure 45 This illustrates the broadband matching degree of a second lens in an optional optical system provided by an embodiment of this application;

[0129] Figure 46 This illustration shows a schematic diagram of phase modulation of the second lens at different wavelengths in another optional optical system provided in this application embodiment;

[0130] Figure 47An astigmatism diagram of yet another optional optical system provided in an embodiment of this application is shown;

[0131] Figure 48 The distortion diagram of another optional optical system provided in the embodiments of this application is shown;

[0132] Figure 49 This illustrates the broadband matching degree of a second lens in an optional optical system provided by an embodiment of this application;

[0133] Figure 50 This illustration shows a schematic diagram of phase modulation of the second lens at different wavelengths in another optional optical system provided in this application embodiment;

[0134] Figure 51 An astigmatism diagram of yet another optional optical system provided in an embodiment of this application is shown;

[0135] Figure 52 The distortion diagram of another optional optical system provided in the embodiments of this application is shown;

[0136] Figure 53 This illustrates the broadband matching degree of a second lens in an optional optical system provided by an embodiment of this application;

[0137] Figure 54 This illustration shows a schematic diagram of phase modulation of the second lens at different wavelengths in another optional optical system provided in this application embodiment;

[0138] Figure 55 An astigmatism diagram of yet another optional optical system provided in an embodiment of this application is shown;

[0139] Figure 56 The distortion diagram of another optional optical system provided in the embodiments of this application is shown;

[0140] Figure 57 This illustrates the broadband matching degree of a second lens in an optional optical system provided by an embodiment of this application;

[0141] Figure 58 This illustration shows a schematic diagram of phase modulation of the second lens at different wavelengths in another optional optical system provided in this application embodiment;

[0142] Figure 59 An astigmatism diagram of yet another optional optical system provided in an embodiment of this application is shown;

[0143] Figure 60 The distortion diagram of another optional optical system provided in the embodiments of this application is shown;

[0144] Figure 61This illustrates the broadband matching degree of a second lens in an optional optical system provided by an embodiment of this application;

[0145] Figure 62 This illustration shows a schematic diagram of phase modulation of the second lens at different wavelengths in another optional optical system provided in this application embodiment;

[0146] Figure 63 An astigmatism diagram of yet another optional optical system provided in an embodiment of this application is shown;

[0147] Figure 64 The distortion diagram of another optional optical system provided in the embodiments of this application is shown;

[0148] Figure 65 This illustrates the broadband matching degree of a second lens in an optional optical system provided by an embodiment of this application;

[0149] Figure 66 This illustration shows a schematic diagram of phase modulation of the second lens at different wavelengths in another optional optical system provided in this application embodiment;

[0150] Figure 67 An astigmatism diagram of yet another optional optical system provided in an embodiment of this application is shown;

[0151] Figure 68 The distortion diagram of another optional optical system provided in the embodiments of this application is shown;

[0152] Figure 69 This illustrates the broadband matching degree of a second lens in an optional optical system provided by an embodiment of this application.

[0153] The reference numerals in the figure represent:

[0154] 10 - First lens; 20 - Second lens; 30 - Third lens; 40 - Fourth lens; 50 - Fifth lens; 60 - Sixth lens; 70 - Aperture stop; 80 - Infrared filter;

[0155] 201-Base layer; 202-Nanostructure layer; 203-Antireflective coating; 204-Photoresist; 205-Reference structure; 202a-Structural layer material;

[0156] 2021 - Nanostructure; 2022 - Filler; 2023 - Superstructure unit. Detailed Implementation

[0157] The present application will now be described more fully below with reference to the accompanying drawings, in which various embodiments are illustrated. However, the present application may be implemented in many different ways and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that the present application will be exhaustive and complete, and will fully convey the scope of the present application to those skilled in the art. The same reference numerals denote the same parts throughout the drawings. Furthermore, in the drawings, the thickness, proportions, and dimensions of parts are enlarged for clarity.

[0158] The terminology used herein is for descriptive purposes only and is not intended to be limiting. Unless the context clearly indicates otherwise, the terms “a,” “an,” “the,” and “at least one” as used herein are not intended to limit the quantity but are intended to include both singular and plural forms. For example, unless the context clearly indicates otherwise, “a component” has the same meaning as “at least one component.” “At least one” should not be construed as limited to the quantity “a.” “Or” means “and / or.” The term “and / or” includes any and all combinations of one or more of the associated listed items.

[0159] Unless otherwise specified, all terms used herein, including technical and scientific terms, shall have the same meaning as commonly understood by one of ordinary skill in the art. Terms defined in commonly used dictionaries shall be interpreted as having the same meaning as in the relevant technical context, and shall not be construed as having a formal meaning in an idealized or overly formal sense unless expressly defined in the specification.

[0160] The meaning of “includes” or “contains” specifies a nature, quantity, step, operation, component, part, or combination thereof, but does not exclude other natures, quantities, steps, operations, components, parts, or combinations thereof.

[0161] This document describes embodiments with reference to cross-sectional views as idealized implementations. Thus, variations in shape relative to the illustrations are anticipated as a result of, for example, manufacturing techniques and / or tolerances. Therefore, the embodiments described herein should not be construed as limited to the specific shapes of the regions shown herein, but should include deviations in shape due to, for example, manufacturing processes. For example, regions shown or described as flat may typically have rough and / or non-linear characteristics. Furthermore, acute angles shown may be rounded. Therefore, the regions shown in the figures are schematic in nature, and their shapes are not intended to show precise shapes of the regions and are not intended to limit the scope of the claims.

[0162] In the following description, exemplary embodiments according to this application will be described with reference to the accompanying drawings.

[0163] In the miniaturization of optical systems, optical systems using traditional plastic lenses are limited by their injection molding process, making it difficult to achieve breakthroughs in thickness and large curvature. This results in limitations in the thickness of individual lenses, the spacing between lenses, and the overall system length for six-element optical systems. Furthermore, the availability of only a dozen or so materials for plastic lenses restricts the freedom of aberration correction in optical systems. While glass-resin hybrid lenses have addressed chromatic aberration to some extent, the processing of aspherical glass and injection molding processes still significantly hinder the miniaturization and weight reduction of optical systems. Currently, reducing the overall length of an optical system by even 1 millimeter requires tremendous effort. Moreover, existing six-element optical systems suffer from low yield rates due to manufacturing limitations.

[0164] In a first aspect, embodiments of this application provide an optical system, such as Figures 1 to 10 As shown, the optical system includes a first lens 10, a second lens 20, a third lens 30, a fourth lens 40, a fifth lens 50, and a sixth lens 60, arranged sequentially from the object side to the image side. The first lens 10 is an aspherical refractive lens, the second lens 20 is a superlens, and the remaining lenses are all refractive lenses. Furthermore, all surfaces of the third lens 30, fourth lens 40, fifth lens 50, and sixth lens 60 include at least one aspherical surface, and this aspherical surface contains a point of inflection.

[0165] The first lens 10 has positive optical power, and its object-side surface is convex; the image-side surface of the third lens 30 is convex; the object-side surface of the fourth lens 40 is concave; and the radii of curvature of the object-side surfaces of the fifth lens 50 and the sixth lens 60 are both negative. Furthermore, the optical system provided in this embodiment also satisfies the following formulas (1-1) to (1-4):

[0166] f / EPD < 3; (1-1)

[0167] 25°≤HFOV≤55°; (1-2)

[0168] 0.05mm≤d2≤2mm; (1-3)

[0169] |f²| / f≥10; (1-4)

[0170] Where f is the focal length of the optical system; EPD is the entrance pupil diameter of the optical system; HFOV is half of the maximum field of view of the optical system; d2 is the thickness of the second lens 20; and f2 is the focal length of the second lens 20. This layout helps to reduce the total system length of the optical system. If the values ​​exceed the formulas (1-1) to (1-4) above, the resolution of the optical system will decrease and the total system length will increase. The total system length (TTL) mentioned above refers to the distance from the object-side surface of the first lens 10 to the image plane of the optical system. The surface of the refractive lens mentioned above refers to the object-side surface and the image-side surface of the refractive lens. For a schematic diagram of the superlens structure, please refer to [link to schematic diagram]. Figures 11 to 29 In this embodiment, the second lens 20 is preferably a planar superlens. Alternatively, the second lens 20 may be a non-planar superlens.

[0171] In an optional implementation, the optical system provided in this application embodiment also satisfies the following formula (2):

[0172] 0.35≤R 1o / f1≤0.58; (2)

[0173] Among them, R 1o f1 is the radius of curvature of the object-side surface of the first lens 10; f1 is the focal length of the first lens 10.

[0174] According to the embodiments of this application, optionally, the optical system provided in the embodiments of this application also satisfies the following formula (3):

[0175] (V1+V4) / 2-V3>20; (3)

[0176] Wherein, V1 is the Abbe number of the first lens 10; V3 is the Abbe number of the third lens 30; and V4 is the Abbe number of the fourth lens 40. The optical system provided in this application embodiment satisfies the above formula (3), which can reduce the size of the optical system and improve the edge image quality of the image formed by the optical system, avoiding dark edges of the image. Furthermore, this layout is beneficial for compressing the overall length of the optical system.

[0177] In some optional embodiments of this application, the optical system also satisfies:

[0178] 0.55 <ImgH / TTL<0.82; (4)

[0179] Wherein, ImgH is the maximum image height of the optical system; the maximum image height refers to half the diagonal length of the effective sensing area of ​​the electronic photosensitive element. TTL is the distance from the object-side surface of the first lens 10 to the imaging surface of the optical system.

[0180] In some alternative embodiments of this application, the image-side surface of the fourth lens 40 in the optical system is also concave, and satisfies:

[0181] R 4i ×R 4o >0; (5)

[0182] Among them, R 4o R is the radius of curvature of the object-side surface of the fourth lens 40. 4i Let be the radius of curvature of the image-side surface of the fourth lens 40. That is, both the object-side surface and the image-side surface of the fourth lens 40 are concave, and the product of the radius of curvature of the object-side surface and the radius of curvature of the image-side surface of the fourth lens 40 is greater than zero.

[0183] According to some alternative embodiments of this application, the optical system also satisfies the following formula (6):

[0184] 0.58≤f1 / f≤0.85; (6)

[0185] Where f1 is the focal length of the first lens 10; f is the focal length of the optical system. The ratio of the focal length of the first lens 10 to the focal length of the optical system satisfies formula (6), which is beneficial to compressing the total length of the optical system.

[0186] According to some optional embodiments of this application, any one or more of the third lens 30, fourth lens 40, fifth lens 50, and sixth lens 60 in the optical system are aspherical refractive lenses. Exemplarily, in the optical system provided by the embodiments of this application, the third to sixth lenses are all aspherical refractive lenses.

[0187] In the optical system provided in this application embodiment, the aspherical surfaces on the object-side and image-side surfaces of all lenses except the second lens 20 are as shown in formula (7):

[0188]

[0189] In formula (7), z is the surface vector parallel to the optical axis of the optical system provided in the embodiment of this application, c is the curvature (1 / R) of the center point of the aspherical surface, k is the quadratic surface constant, and A to J correspond to higher order coefficients respectively.

[0190] In some optional embodiments, the optical system provided in this application also includes an aperture stop 70, such as an aperture stop (STO). Theoretically, the aperture stop 70 can be disposed on one side of any lens in the optical system. Optionally, in the optical system of this application embodiment, the aperture stop 70 is disposed on the side of the first lens 10 closer to the object side. This arrangement can help control the aperture of the entire optical system, so as to avoid the aperture of the optical system being too large and thus hindering the miniaturization of the optical system.

[0191] In some alternative embodiments, the optical system provided in this application further includes an infrared filter 80. Exemplarily, the infrared filter 80 is disposed between the sixth lens 60 and the image plane of the optical system. Exemplarily, when the operating wavelength of the optical system is the visible light band, the infrared filter helps to filter infrared radiation in the incident radiation, which helps to reduce the heat generated by the incident radiation, prevents infrared radiation from burning the sensor located downstream of the optical system, and also helps to reduce the distortion of the optical system's imaging, thereby improving the imaging quality of the optical system.

[0192] The superlens (i.e., the second lens 20) provided in the embodiments of this application will now be described in detail. It will be understood that a superlens is a specific application of a metasurface, which modulates the phase, amplitude, and polarization of incident light through periodically arranged subwavelength nanostructures. According to the embodiments of this application, as... Figure 11 As shown, the superlens (i.e., the second lens 20) in the optical system includes a substrate layer 201 and at least one nanostructure layer 202 disposed on one side of the substrate layer 201. Each nanostructure layer 202 comprises periodically arranged nanostructures 2021. The aforementioned substrate layer 201 and nanostructure layer 202 are configured to transmit radiation in the operating wavelength band of the optical system provided in this embodiment.

[0193] According to embodiments of this application, optionally, in any one of the at least one nanostructure layer 202, the arrangement period of the nanostructure 2021 is greater than or equal to 0.3λ. c And less than or equal to 2λ c ; where λ c This is the center wavelength of the operating band of the optical system.

[0194] According to embodiments of this application, optionally, the height of the nanostructure 2021 in any one of the at least one nanostructure layer 202 is greater than or equal to 0.3λ. c And less than or equal to 5λ c ; where λ c This is the center wavelength of the operating band of the optical system.

[0195] Figure 12 and Figure 13 This illustration shows a perspective view of nanostructure 2021 in any nanostructure layer 202 of the superlens provided in an embodiment of this application. Optionally, Figure 12 It has a cylindrical structure. Optionally, Figure 13 The nanostructure 2021 in the image is a square prismatic structure. Optionally, such as... Figure 12 and Figure 13As shown, the superlens also includes a filler 2022, which fills the spaces between the nanostructures 2021, and the material of the filler 2022 has an extinction coefficient of less than 0.01 for the operating wavelength. Optionally, the filler may include air or other materials that are transparent or translucent for the operating wavelength. According to embodiments of this application, the absolute value of the difference between the refractive index of the filler 2022 material and the refractive index of the nanostructure 2021 should be greater than or equal to 0.5. Exemplarily, when the superlens provided in the embodiments of this application has at least two nanostructure layers 202, the filler 2022 in the nanostructure layer 202 furthest from the substrate layer 201 may be air.

[0196] In some optional embodiments of this application, such as Figures 14 to 16 As shown, nanostructures 2021 in any layer of at least one nanostructure layer 202 are periodically arranged in the form of superstructure units 2023. The superstructure unit 2023 is a densely stackable pattern, with nanostructures 2021 disposed at its vertices and / or center. In this embodiment, a densely stackable pattern refers to one or more patterns that can fill the entire plane without gaps or overlaps.

[0197] like Figure 14 As shown, according to an embodiment of this application, the superstructure units can be arranged in a fan shape. Figure 15 As shown, according to an embodiment of this application, the superstructure units can be arranged in a regular hexagonal array. Furthermore, as... Figure 16 As shown, according to an embodiment of this application, the superstructure unit 2023 can be arranged in a square array. Those skilled in the art will recognize that the superstructure unit 2023 included in the nanostructure layer 202 can also include other forms of array arrangement, and all such variations are covered within the scope of this application.

[0198] Optionally, the broadband phase of the superstructure unit 2023 provided in this application embodiment also satisfies the following requirements regarding the operating wavelength of the superlens:

[0199]

[0200] In formula (8), r is the radial coordinate of the superlens; r0 is the distance from any point on the superlens to the center of the superlens; and λ is the working wavelength of the superlens.

[0201] For example, the nanostructure 2021 provided in the embodiments of this application can be a polarization-independent structure, such a structure imposing a propagation phase on the incident light. According to embodiments of this application, such as Figure 17 , Figure 18 and Figure 19As shown, nanostructure 2021 can be either a positive or negative structure. For example, the shapes of nanostructure 2021 include cylinders, hollow cylinders, square prisms, and hollow square prisms.

[0202] More advantageously, such as Figure 20 As shown, the second lens 20 provided in this embodiment includes at least two nanostructure layers 202. Optionally, see... Figure 21 In (a) of at least two nanostructure layers 202, the nanostructures 2021 in adjacent nanostructure layers are arranged coaxially. The aforementioned coaxial arrangement means that the nanostructures 2021 in two adjacent nanostructure layers 202 have the same periodicity; or that the axes of nanostructures 2021 at the same position in two adjacent nanostructure layers coincide. Optionally, see [reference needed]. Figure 21 In (b), the nanostructures 2021 in adjacent nanostructure layers of at least two nanostructures 202 are staggered along a direction parallel to the substrate of the superlens. This arrangement helps to overcome the limitations of fabrication technology on the aspect ratio of nanostructures in the superlens, thereby achieving greater design freedom. Figure 20 A perspective view of an optional three-layer nanostructure is shown. Figure 20 The middle left figure shows a perspective view of an optional three-layer nanostructure. Figure 20 The right-middle figure shows a top view of each nanostructure layer. According to embodiments of this application, the shape, size, or material of the nanostructures 2021 in adjacent nanostructure layers 202 may be the same or different. According to embodiments of this application, the fillers 2022 in adjacent nanostructure layers 202 may be the same or different.

[0203] For example, Figure 17 a to Figure 17 The d in the figure shows that the shape of the nanostructure 2021 includes a cylinder, a hollow cylinder, a square cylinder, and a hollow square cylinder, and the nanostructure 2021 is surrounded by filler 2022. Figure 17 In this embodiment, the nanostructure 2021 is positioned at the center of the quadrilateral superstructure unit 2023. In an optional embodiment of this application, Figure 18 a to Figure 18 The d in the figure shows the shapes of the nanostructure 2021, including cylinder, hollow cylinder, square cylinder and hollow square cylinder, and there is no filler 2022 around the nanostructure 2021. Figure 18 In this structure, nanostructure 2021 is positioned at the center of the quadrilateral superstructure unit 2023.

[0204] According to the embodiments of this application, Figure 19 a to Figure 19The d in the figure shows that the shape of the nanostructure 2021 includes a square column, a cylinder, a hollow square column, and a hollow cylinder, and there is no filler 2022 around the nanostructure 2021. Figure 19 a to Figure 19 In d, the nanostructure 2021 is positioned at the center of the hexagonal superstructure unit 2023. Optionally, Figure 19 e to Figure 19 The h in the figure represents the nanostructures 2021, which are negative nanostructures, such as square pore pillars, circular pore pillars, square ring pillars, and circular ring pillars. Figure 19 e to Figure 19 In h, nanostructure 2021 is a negative structure located at the center of the superstructure unit 2023 in a regular hexagon.

[0205] In one alternative implementation, such as Figure 22 As shown, the superlens provided in this embodiment further includes an antireflective coating 203. The antireflective coating 203 is disposed on the side of the substrate layer 201 away from the nanostructure layer 202; or, the antireflective coating 203 is disposed on the side of the nanostructure layer 202 adjacent to air. The function of the antireflective coating 203 is to increase the transmission and reduce the reflection of incident radiation.

[0206] According to embodiments of this application, optionally, the material of the substrate 201 is a material with an extinction coefficient of less than 0.01 for the working wavelength band. For example, the material of the substrate 201 includes any one or more combinations of fused silica, quartz glass, crown glass, flint glass, sapphire, crystalline silicon, amorphous silicon, and hydrogenated amorphous silicon. As another example, when the working wavelength band of the superlens is the visible light band, the material of the substrate 201 includes any one or more combinations of fused silica, quartz glass, crown glass, flint glass, sapphire, and alkaline glass. In some embodiments of this application, the material of the nanostructure 2021 is the same as the material of the substrate 201. In still other embodiments of this application, the material of the nanostructure 2021 is different from the material of the substrate 201. Optionally, the material of the filler 2022 is the same as the material of the substrate 201. Optionally, the material of the filler 2022 is different from the material of the substrate 201.

[0207] It should be understood that in some optional embodiments of this application, the filler 2022 and the nanostructure 2021 are made of the same material. In still some optional embodiments of this application, the filler 2022 and the nanostructure 2021 are made of different materials. For example, the material of the filler 2022 is a high-transmittance material in the working wavelength band, with an extinction coefficient of less than 0.01. For example, the material of the filler 2022 includes fused silica, quartz glass, crown glass, flint glass, sapphire, crystalline silicon, amorphous silicon, and hydrogenated amorphous silicon.

[0208] Optionally, the equivalent refractive index range of the superlens provided in this application embodiment is less than 2. The equivalent refractive index range is the maximum refractive index of the superlens minus its minimum refractive index. According to the embodiments of this application, the phase of the superlens provided in this application embodiment also satisfies formulas (9-1) to (9-8):

[0209]

[0210]

[0211]

[0212]

[0213]

[0214]

[0215]

[0216]

[0217] In formulas (9-1) to (9-8) above, r is the distance from the center of the superlens to the center of any nanostructure; λ is the operating wavelength of the superlens. Let f1 be any phase related to the operating wavelength, (x, y) be the coordinates on the superlens (in some cases, this can be understood as the coordinates on the surface of the substrate 201), f2 be the focal length of the superlens, and a be the focal length of the superlens. i and b i The coefficients are real numbers. The phase of the superlens (i.e., the second lens 20) can be expressed by a high-order polynomial, which includes odd-order and even-order polynomials. In order not to destroy the rotational symmetry of the superlens phase, usually only the phase corresponding to the even-order polynomial can be optimized, which greatly reduces the design freedom of the superlens. However, among the above formulas (9-1) to (9-8), formulas (9-4) to (9-6) can optimize the phase that satisfies the odd-order polynomial without destroying the rotational symmetry of the superlens phase, thereby greatly improving the optimization freedom of the superlens.

[0218] Optionally, the matching between the actual phase and the ideal phase of the superlens provided in this application embodiment, that is, the broadband phase matching degree of the second lens 20, is given by formula (10):

[0219]

[0220] In formula (10) λ max and λ min These represent the upper and lower limits of the operating wavelength of the superlens, for example, λ.max =700nm, λ min =400nm. and These are the theoretical target phase and the actual phase within the database, respectively.

[0221] Example 1

[0222] This application provides a superlens comprising a substrate layer 201 and two nanostructure layers 202 disposed on the substrate layer 201, wherein the two nanostructure layers 202 are, in order, a first nanostructure layer and a second nanostructure layer along the direction away from the substrate layer 201. The specific structural parameters of the superlens are shown in Table 1. Figure 23 The phase diagram of the superlens provided in Embodiment 1 is shown. Figure 23 The horizontal axis represents the wavelength of the incident radiation, and the vertical axis represents the nanostructure 2022 designation. Figure 24 A schematic diagram of the transmittance of the superlens provided in Example 1 is shown. Figure 24 The horizontal axis represents the wavelength of the incident radiation, and the vertical axis represents the nanostructure 2022 designation.

[0223] Table 1

[0224]

[0225] Example 2

[0226] This application provides an exemplary superlens comprising a substrate layer 201 and two nanostructure layers 202 disposed on the substrate layer 201, wherein the two nanostructure layers 202 are, in order, a first nanostructure layer and a second nanostructure layer along the direction away from the substrate layer 201. The specific structural parameters of the superlens are shown in Table 2. Figure 25 The phase diagram of the superlens provided in Embodiment 1 is shown. Figure 25 The horizontal axis represents the wavelength of the incident radiation, and the vertical axis represents the nanostructure 2022 designation. Figure 26 A schematic diagram of the transmittance of the superlens provided in Example 1 is shown. Figure 26 The horizontal axis represents the wavelength of the incident radiation, and the vertical axis represents the nanostructure 2022 designation.

[0227] Table 2

[0228]

[0229] This application also provides a method for fabricating a superlens, such as... Figures 27 to 29 As shown, the method includes at least steps S1 to S5.

[0230] Step S1: A structural layer material 202a is disposed on the base layer 201.

[0231] Step S2: Photoresist 204 is coated on the structural layer material 202a, and the reference structure 205 is exposed.

[0232] Step S3: Based on the reference structure 206, periodically arranged nanostructures 2021 are etched on the structural layer material 202a to form a nanostructure layer 202.

[0233] Step S4: Filler 2022 is placed between the nanostructures 2021.

[0234] Step S5: Trim the surface of filler 2022 so that the surface of filler 2022 coincides with the surface of nanostructure 2021.

[0235] Optionally, such as Figure 28 As shown, the method provided in this application embodiment further includes:

[0236] Step S6: Repeat steps S1 to S5 until all nanostructure layers are set.

[0237] Example 3

[0238] This application provides an exemplary optical system, such as... Figure 1 As shown, the optical system includes components along the object-to-image axis (…). Figure 1 The aperture stop (STO), first lens 10, second lens 20, third lens 30, fourth lens 40, fifth lens 50, and sixth lens 60 are arranged sequentially from left to right. Optionally, as... Figure 1 As shown, an infrared filter is also disposed between the sixth lens 60 and the image plane of the optical system. The optical system provided in this application embodiment satisfies formulas (1-1) to (1-4):

[0239] f / EPD < 3; (1-1)

[0240] 25°≤HFOV≤55°; (1-2)

[0241] 0.05mm≤d2≤2mm; (1-3)

[0242] |f²| / f≥10; (1-4)

[0243] Where f is the focal length of the optical system; EPD is the entrance pupil diameter of the optical system; HFOV is half of the maximum field of view of the optical system; d2 is the thickness of the second lens 20; and f2 is the focal length of the second lens 20.

[0244] The specific parameters of the optical system provided in Example 3 are shown in Table 3-1. The parameters of each lens in this optical system, such as the curvature of the object-side and image-side surfaces, the lens thickness, and the refractive index, are shown in Table 3-2. The aspherical coefficients of each surface in this optical system are shown in Tables 3-3-1 and 3-3-2. Figure 30 The diagram shows the phase diagrams of the superlens (i.e., the second lens 20) in the optical system provided in Embodiment 3 at three different wavelengths: 486.13 nm, 587.56 nm, and 656.27 nm. Figure 30 It can be seen that the phase of this optical system covers the 2π phase in different wavebands. Figure 31 An astigmatism diagram of the optical system provided in Embodiment 3 is shown. Figure 31 It can be seen that the astigmatism of this optical system is less than 0.5 mm under different fields of view. Figure 32 A distortion diagram of the optical system provided in an embodiment of this application is shown. Figure 32 It can be seen that the distortion of the optical system is less than 5% under different fields of view. Figure 33 The broadband matching degree of the superlens (i.e., the second lens 20) in this optical system is shown. Figure 33 In this example, the broadband matching degree of the superlens is greater than 90%. As can be seen from the above, the optical system provided in Example 3 produces clear images with excellent control over astigmatism and distortion, resulting in superior image quality.

[0245] Table 3-1

[0246]

[0247]

[0248] Table 3-2

[0249]

[0250] Table 3-3-1

[0251] <![CDATA[L 1o ]]> <![CDATA[L 1i ]]> <![CDATA[L 3o ]]> <![CDATA[L 3i ]]> <![CDATA[L 4o ]]> <![CDATA[L 4i ]]> K -4.930885 -9.967591 -2.48E+16 -9.967591 -19.73647 -21.66745 A 0.2816075 -0.03333 -0.056678 -0.03333 -0.130666 -0.061622 B -0.219687 -0.00782 0.2996243 -0.00782 0.0049981 -0.093319 C 0.2763091 -0.154566 0.1635329 -0.154566 0.3531215 0.1416254 D -0.239358 0.3416499 -0.823191 0.3416499 -0.519927 0.1471917 E 0.0782505 -0.331173 0.6670421 -0.331173 0.3548887 0.1339349 F 0.1286909 0.020975 -0.71871 0.020975 0.1946845 -0.387356 G -0.204236 2.69E-09 -2.83E-07 2.69E-09 0.1440297 0.2628043

[0252] Table 3-3-2

[0253] Surface number <![CDATA[L 5o ]]> <![CDATA[L 5i ]]> <![CDATA[L 6o ]]> <![CDATA[L 6i ]]> K -16.91132 -7.037279 -0.273635 -32951.91 A -0.195216 -0.14831 -0.104358 -0.096956 B 0.0789743 0.1313335 0.0351653 0.0340921 C -0.007882 -0.098632 0.0186416 -0.008377 D 0.1315148 0.0752048 -0.015745 0.0010368 E -0.191226 -0.025525 -0.003201 -0.000259 F 0.8238655 -0.006899 0.004528 6.16E-05 G -1.021081 0.0017734 -0.001074 -5.50E-06

[0254] Example 4

[0255] This application provides an exemplary optical system, such as... Figure 2 As shown, the optical system includes components along the object-to-image axis (…). Figure 2 The aperture stop (STO), first lens 10, second lens 20, third lens 30, fourth lens 40, fifth lens 50, and sixth lens 60 are arranged sequentially from left to right. Optionally, as... Figure 2 As shown, an infrared filter is also disposed between the sixth lens 60 and the image plane of the optical system. The optical system provided in this application embodiment satisfies formulas (1-1) to (1-4):

[0256] f / EPD < 3; (1-1)

[0257] 25°≤HFOV≤55°; (1-2)

[0258] 0.05mm≤d2≤2mm; (1-3)

[0259] |f²| / f≥10; (1-4)

[0260] Where f is the focal length of the optical system; EPD is the entrance pupil diameter of the optical system; HFOV is half of the maximum field of view of the optical system; d2 is the thickness of the second lens 20; and f2 is the focal length of the second lens 20.

[0261] The specific parameters of the optical system provided in Example 4 are shown in Table 4-1. The parameters of each lens in this optical system, such as the curvature of the object-side and image-side surfaces, the lens thickness, and the refractive index, are shown in Table 4-2. The aspherical coefficients of each surface in this optical system are shown in Tables 4-3-1 and 4-3-2. Figure 34 The diagram shows the phase diagrams of the superlens (i.e., the second lens 20) in the optical system provided in Embodiment 4 at three different wavelengths: 486.13 nm, 587.56 nm, and 656.27 nm. Figure 34 It can be seen that the phase of this optical system covers the 2π phase in different wavebands. Figure 35 An astigmatism diagram of the optical system provided in Embodiment 4 is shown. Figure 35 It can be seen that the astigmatism of this optical system is less than 1 mm under different fields of view. Figure 36 A distortion diagram of the optical system provided in an embodiment of this application is shown. Figure 36 It can be seen that the distortion of this optical system is much less than 5% under different fields of view. Figure 37 The broadband matching degree of the superlens (i.e., the second lens 20) in this optical system is shown. Figure 37 In this example, the broadband matching degree of the superlens is greater than 90%. As can be seen from the above, the optical system provided in Example 4 produces clear images with excellent control over astigmatism and distortion, resulting in superior image quality.

[0262] Table 4-1

[0263] Parameter Items Numerical Operating band (WL) VIS (400-700nm) Equivalent Focal Length (EFL) 4.35mm Field of view (2ω) 66.4° F number 2.8 Like high (ImgH) 2.86mm Total system length (TTL) 4.5mm

[0264] Table 4-2

[0265]

[0266]

[0267] Table 4-3-1

[0268] Surface number <![CDATA[L 1o ]]> <![CDATA[L 1i ]]> <![CDATA[L 3o ]]> <![CDATA[L 3i ]]> <![CDATA[L 4o ]]> <![CDATA[L 4i ]]> K -5.966288 -2.42E+12 -3391307 8.9055836 -2.71E+11 3579845.4 A 0.2329433 0.0225779 0.0443395 0.0226629 -0.170495 -0.180514 B -0.190949 0.084131 -0.020353 0.0068781 -0.165075 -0.179473 C 0.2424773 -0.244019 0.3302705 0.1209795 0.3803641 0.1265254 D -0.243905 0.3094722 -0.910611 -0.309296 -0.451703 -0.092659 E 0.222551 -0.007697 1.2541605 0.4405919 0.1609811 -0.024171 F -0.073802 -0.257869 -0.789407 -0.215005 -0.032096 -0.014726 G -0.014898 0.0995529 0.099149 -0.022872 0.0635873 0.0137494

[0269] Table 4-3-2

[0270] Surface number <![CDATA[L 5o ]]> <![CDATA[L 5i ]]> <![CDATA[L 6o ]]> <![CDATA[L 6i ]]> K 7.393398 -9.831377 -1.170412 -1.08E+13 A -0.035292 -0.126365 -0.028974 -0.070661 B -0.02804 0.1243273 -0.026741 0.0042895 C -0.259869 -0.111802 0.017541 -0.005223 D 0.2856444 0.0678893 -1.33E-06 0.0018629 E -0.171787 -0.018036 -0.000505 -0.000157 F 0.0236541 0.0012701 -0.000117 7.58E-06 G -0.024701 6.25E-05 2.49E-05 -4.66E-06

[0271] Example 5

[0272] This application provides an exemplary optical system, such as... Figure 3 As shown, the optical system includes components along the object-to-image axis (…). Figure 3 The aperture stop (STO), first lens 10, second lens 20, third lens 30, fourth lens 40, fifth lens 50, and sixth lens 60 are arranged sequentially from left to right. Optionally, as... Figure 3 As shown, an infrared filter is also disposed between the sixth lens 60 and the image plane of the optical system. The optical system provided in this application embodiment satisfies formulas (1-1) to (1-4):

[0273] f / EPD < 3; (1-1)

[0274] 25°≤HFOV≤55°; (1-2)

[0275] 0.05mm≤d2≤2mm; (1-3)

[0276] |f²| / f≥10; (1-4)

[0277] Where f is the focal length of the optical system; EPD is the entrance pupil diameter of the optical system; HFOV is half of the maximum field of view of the optical system; d2 is the thickness of the second lens 20; and f2 is the focal length of the second lens 20.

[0278] The specific parameters of the optical system provided in Example 5 are shown in Table 5-1. The parameters of each lens in this optical system, such as the curvature of the object-side and image-side surfaces, the lens thickness, and the refractive index, are shown in Table 5-2. The aspherical coefficients of each surface in this optical system are shown in Tables 5-3-1 and 5-3-2. Figure 38 The diagram shows the phase diagrams of the superlens (i.e., the second lens 20) in the optical system provided in Embodiment 5 at three different wavelengths: 486.13 nm, 587.56 nm, and 656.27 nm. Figure 38 It can be seen that the phase of this optical system covers the 2π phase in different wavebands. Figure 39 An astigmatism diagram of the optical system provided in Embodiment 5 is shown. Figure 39 It can be seen that the astigmatism of this optical system is less than 0.5 mm under different fields of view. Figure 40 A distortion diagram of the optical system provided in an embodiment of this application is shown. Figure 40 It can be seen that the distortion of the optical system is less than 5% under different fields of view. Figure 41 The broadband matching degree of the superlens (i.e., the second lens 20) in this optical system is shown. Figure 41 In this example, the broadband matching degree of the superlens is greater than 90%. As can be seen from the above, the optical system provided in Example 5 produces clear images with excellent control over astigmatism and distortion, resulting in superior image quality.

[0279] Table 5-1

[0280] Parameter Items Numerical Operating band (WL) VIS (400-700nm) Equivalent Focal Length (EFL) 4.35mm Field of view (2ω) 66.4° F number 2.8 Like high (ImgH) 2.86mm Total system length (TTL) 4.5mm

[0281] Table 5-2

[0282]

[0283]

[0284] Table 5-3-1

[0285] Surface number <![CDATA[L 1o ]]> <![CDATA[L 1i ]]> <![CDATA[L 3o ]]> <![CDATA[L 3i ]]> <![CDATA[L 4o ]]> <![CDATA[L 4i ]]> K -5.966288 -2.42E+12 -3391307 8.9055836 -2.71E+11 3579845.4 A 0.2329433 0.0225779 0.0443395 0.0226629 -0.170495 -0.180514 B -0.190949 0.084131 -0.020353 0.0068781 -0.165075 -0.179473 C 0.2424773 -0.244019 0.3302705 0.1209795 0.3803641 0.1265254 D -0.243905 0.3094722 -0.910611 -0.309296 -0.451703 -0.092659 E 0.222551 -0.007697 1.2541605 0.4405919 0.1609811 -0.024171 F -0.073802 -0.257869 -0.789407 -0.215005 -0.032096 -0.014726 G -0.014898 0.0995529 0.099149 -0.022872 0.0635873 0.0137494

[0286] Table 5-3-2

[0287] Surface number <![CDATA[L 5o ]]> <![CDATA[L 5i ]]> <![CDATA[L 6o ]]> <![CDATA[L 6i ]]> K 7.393398 -9.831377 -1.170412 -1.08E+13 A -0.035292 -0.126365 -0.028974 -0.070661 B -0.02804 0.1243273 -0.026741 0.0042895 C -0.259869 -0.111802 0.017541 -0.005223 D 0.2856444 0.0678893 -1.33E-06 0.0018629 E -0.171787 -0.018036 -0.000505 -0.000157 F 0.0236541 0.0012701 -0.000117 7.58E-06 G -0.024701 6.25E-05 2.49E-05 -4.66E-06

[0288] Example 6

[0289] This application provides an exemplary optical system, such as... Figure 4 As shown, the optical system includes components along the object-to-image axis (…). Figure 4 The aperture stop (STO), first lens 10, second lens 20, third lens 30, fourth lens 40, fifth lens 50, and sixth lens 60 are arranged sequentially from left to right. Optionally, as... Figure 4 As shown, an infrared filter is also disposed between the sixth lens 60 and the image plane of the optical system. The optical system provided in this application embodiment satisfies formulas (1-1) to (1-4):

[0290] f / EPD < 3; (1-1)

[0291] 25°≤HFOV≤55°; (1-2)

[0292] 0.05mm≤d2≤2mm; (1-3)

[0293] |f²| / f≥10; (1-4)

[0294] Where f is the focal length of the optical system; EPD is the entrance pupil diameter of the optical system; HFOV is half of the maximum field of view of the optical system; d2 is the thickness of the second lens 20; and f2 is the focal length of the second lens 20.

[0295] The specific parameters of the optical system provided in Example 6 are shown in Table 6-1. The parameters of each lens in this optical system, such as the curvature of the object-side and image-side surfaces, the lens thickness, and the refractive index, are shown in Table 6-2. The aspherical coefficients of each surface in this optical system are shown in Tables 6-3-1 and 6-3-2. Figure 42 The diagram shows the phase diagrams of the superlens (i.e., the second lens 20) in the optical system provided in Embodiment 6 at three different wavelengths: 486.13 nm, 587.56 nm, and 656.27 nm. Figure 42 It can be seen that the phase of this optical system covers the 2π phase in different wavebands. Figure 43 An astigmatism diagram of the optical system provided in Embodiment 6 is shown. Figure 43 It can be seen that the astigmatism of this optical system is less than 0.5 mm under different fields of view. Figure 44 The distortion diagram of the optical system provided in an embodiment of this application is shown. Figure 44 It can be seen that the distortion of this optical system is much less than 5% under different fields of view. Figure 45 The broadband matching degree of the superlens (i.e., the second lens 20) in this optical system is shown. Figure 45 In this example, the broadband matching degree of the superlens is greater than 90%. As can be seen from the above, the optical system provided in Example 6 produces clear images with excellent control over astigmatism and distortion, resulting in superior image quality.

[0296] Table 6-1

[0297]

[0298]

[0299] Table 6-2

[0300] Surface number Surface type Radius (mm) Thickness (mm) Material STO spherical unlimited -0.179 <![CDATA[L 1o ]]> aspherical 1.502 0.4439 540000.560000 <![CDATA[L 1i ]]> aspherical -57.746 0.05 <![CDATA[L 2o ]]> metasurface unlimited 0.1 458000.676000 <![CDATA[L 2i ]]> spherical unlimited 0.05 <![CDATA[L 3o ]]> aspherical -162.64 0.5014 650000.214000 <![CDATA[L 3i ]]> aspherical 3.28 0.3897 <![CDATA[L 4o ]]> aspherical -75.68 0.2437 544000.559000 <![CDATA[L 4i ]]> aspherical -3528.37 0.2305 <![CDATA[L 5o ]]> aspherical -3.032 0.6624 544000.559000 <![CDATA[L 5i ]]> aspherical -1.385 0.833 <![CDATA[L 6o ]]> aspherical -1.441 0.437 544000.559000 <![CDATA[L 6i ]]> aspherical 103.45 0.309 <![CDATA[IR filter o ]]> spherical unlimited 0.2 517000.642000 <![CDATA[IR filter i ]]> spherical unlimited 0.351 Image plane spherical unlimited 0

[0301] Table 6-3-1

[0302]

[0303]

[0304] Table 6-3-2

[0305] Surface number <![CDATA[L 5o ]]> <![CDATA[L 5i ]]> <![CDATA[L 6o ]]> <![CDATA[L 6i ]]> K 5.449457 -4.418018 -1.591146 -923370.9 A -0.023181 -0.146235 -0.020388 -0.062532 B -0.014869 0.1181804 -0.029459 0.0096317 C -0.242987 -0.114044 0.0116144 -0.005348 D 0.2913974 0.0673508 -0.001066 0.0016265 E -0.172454 -0.01805 -0.000278 -0.000196 F 0.0284623 0.0013237 -7.08E-06 6.84E-06 G -0.008201 7.92E-05 -1.21E-05 -1.75E-06

[0306] Example 7

[0307] This application provides an exemplary optical system, such as... Figure 5 As shown, the optical system includes components along the object-to-image axis (…). Figure 5 The aperture stop (STO), first lens 10, second lens 20, third lens 30, fourth lens 40, fifth lens 50, and sixth lens 60 are arranged sequentially from left to right. Optionally, as... Figure 50 As shown, an infrared filter is also disposed between the sixth lens 60 and the image plane of the optical system. The optical system provided in this application embodiment satisfies formulas (1-1) to (1-4):

[0308] f / EPD < 3; (1-1)

[0309] 25°≤HFOV≤55°; (1-2)

[0310] 0.05mm≤d2≤2mm; (1-3)

[0311] |f²| / f≥10; (1-4)

[0312] Where f is the focal length of the optical system; EPD is the entrance pupil diameter of the optical system; HFOV is half of the maximum field of view of the optical system; d2 is the thickness of the second lens 20; and f2 is the focal length of the second lens 20.

[0313] The specific parameters of the optical system provided in Example 7 are shown in Table 7-1. The parameters of each lens in this optical system, such as the curvature of the object-side and image-side surfaces, the lens thickness, and the refractive index, are shown in Table 7-2. The aspherical coefficients of each surface in this optical system are shown in Tables 7-3-1 and 7-3-2. Figure 46 The diagram shows the phase diagrams of the superlens (i.e., the second lens 20) in the optical system provided in Embodiment 7 at three different wavelengths: 486.13 nm, 587.56 nm, and 656.27 nm. Figure 46 It can be seen that the phase of this optical system covers the 2π phase in different wavebands. Figure 47 An astigmatism diagram of the optical system provided in Embodiment 7 is shown. Figure 47 It can be seen that the astigmatism of this optical system is less than 0.5 mm under different fields of view. Figure 48 A distortion diagram of the optical system provided in an embodiment of this application is shown. Figure 48 It can be seen that the distortion of the optical system is less than 5% under different fields of view. Figure 49 The broadband matching degree of the superlens (i.e., the second lens 20) in this optical system is shown. Figure 49 In this example, the broadband matching degree of the superlens is greater than 90%. As can be seen from the above, the optical system provided in Example 7 produces clear images with excellent control over astigmatism and distortion, resulting in superior image quality.

[0314] Table 7-1

[0315] Parameter Items Numerical Operating band (WL) VIS (400-700nm) Equivalent Focal Length (EFL) 4.35mm Field of view (2ω) 66.4° F number 2.8 Like high (ImgH) 2.86mm Total system length (TTL) 5mm

[0316] Table 7-2

[0317]

[0318]

[0319] Table 7-3-1

[0320]

[0321] Table 7-3-2

[0322]

[0323]

[0324] Example 8

[0325] This application provides an exemplary optical system, such as... Figure 6 As shown, the optical system includes components along the object-to-image axis (…). Figure 6 The first lens 10, the aperture stop (STO), the second lens 20, the third lens 30, the fourth lens 40, the fifth lens 50, and the sixth lens 60 are arranged sequentially from left to right. Optionally, as... Figure 3 As shown, an infrared filter is also disposed between the sixth lens 60 and the image plane of the optical system. The optical system provided in this application embodiment satisfies formulas (1-1) to (1-4):

[0326] f / EPD < 3; (1-1)

[0327] 25°≤HFOV≤55°; (1-2)

[0328] 0.05mm≤d2≤2mm; (1-3)

[0329] |f²| / f≥10; (1-4)

[0330] Where f is the focal length of the optical system; EPD is the entrance pupil diameter of the optical system; HFOV is half of the maximum field of view of the optical system; d2 is the thickness of the second lens 20; and f2 is the focal length of the second lens 20.

[0331] The specific parameters of the optical system provided in Example 8 are shown in Table 8-1. The parameters of each lens in this optical system, such as the curvature of the object-side and image-side surfaces, the lens thickness, and the refractive index, are shown in Table 8-2. The aspherical coefficients of each surface in this optical system are shown in Tables 8-3-1 and 8-3-2. Figure 50 The diagram shows the phase diagrams of the superlens (i.e., the second lens 20) in the optical system provided in Embodiment 8 at three different wavelengths: 486.13 nm, 587.56 nm, and 656.27 nm. Figure 50 It can be seen that the phase of this optical system covers the 2π phase in different wavebands. Figure 51 An astigmatism diagram of the optical system provided in Embodiment 8 is shown. Figure 51 It can be seen that the astigmatism of this optical system is less than 0.5 mm under different fields of view. Figure 52 A distortion diagram of the optical system provided in an embodiment of this application is shown. Figure 52 It can be seen that the distortion of the optical system is less than 5% under different fields of view. Figure 53 The broadband matching degree of the superlens (i.e., the second lens 20) in this optical system is shown. Figure 53 In this example, the broadband matching degree of the superlens is greater than 90%. As can be seen from the above, the optical system provided in Example 8 produces clear images with excellent control over astigmatism and distortion, resulting in superior image quality.

[0332] Table 8-1

[0333] Parameter Items Numerical Operating band (WL) VIS (400-700nm) Equivalent Focal Length (EFL) 4mm Field of view (2ω) 66.4° F number 2.85 Like high (ImgH) 3.014mm Total system length (TTL) 3.8mm

[0334] Table 8-2

[0335]

[0336]

[0337] Table 8-3-1

[0338] Surface number <![CDATA[L 1o ]]> <![CDATA[L 1i ]]> <![CDATA[L 3o ]]> <![CDATA[L 3i ]]> <![CDATA[L 4o ]]> <![CDATA[L 4i ]]> K -4.121835 -0.301316 -2.21E+11 -31.00754 -9.637143 -4.783519 A 0.3143153 -0.040117 -0.01614 -0.011515 -0.220447 -0.201925 B -0.235618 0.0631101 0.2904891 0.3269966 0.0417757 0.0195985 C 0.3037657 -0.19679 0.3198971 0.2285097 0.4684934 0.1731913 D -0.161598 0.3463478 -0.849183 -0.46272 -0.624094 -0.024136 E -0.004637 -0.07463 1.3493986 0.2231465 0.6794831 0.1113262 F -0.031613 0.6074249 -0.674074 0.9021309 0.8751026 0.0902933 G 0.1849747 -1.287904 -0.013711 -0.057478 -4.508269 -0.144805

[0339] Table 8-3-2

[0340] Surface number <![CDATA[L 5o ]]> <![CDATA[L 5i ]]> <![CDATA[L 6o ]]> <![CDATA[L 6i <!-- 27 -->]]> K -1.248789 -3.676745 -2.905965 0.6365684 A -0.16175 -0.08591 -0.000951 0.0036439 B 0.028044 0.1591998 -0.029449 -0.003586 C -0.159878 -0.125683 0.011773 -0.008968 D 0.2038551 0.0664692 -0.000814 0.00332 E -0.241458 -0.017064 -0.000187 -0.000162 F 0.05715 -0.000206 2.10E-05 -0.000112 G 0.1186811 -0.002795 -3.44E-08 1.25E-05

[0341] Example 9

[0342] This application provides an exemplary optical system, such as... Figure 7 As shown, the optical system includes components along the object-to-image axis (…). Figure 7 The first lens 10, the aperture stop (STO), the second lens 20, the third lens 30, the fourth lens 40, the fifth lens 50, and the sixth lens 60 are arranged sequentially from left to right. Optionally, as... Figure 7 As shown, an infrared filter is also disposed between the sixth lens 60 and the image plane of the optical system. The optical system provided in this application embodiment satisfies formulas (1-1) to (1-4):

[0343] f / EPD < 3; (1-1)

[0344] 25°≤HFOV≤55°; (1-2)

[0345] 0.05mm≤d2≤2mm; (1-3)

[0346] |f²| / f≥10; (1-4)

[0347] Where f is the focal length of the optical system; EPD is the entrance pupil diameter of the optical system; HFOV is half of the maximum field of view of the optical system; d2 is the thickness of the second lens 20; and f2 is the focal length of the second lens 20.

[0348] The specific parameters of the optical system provided in Example 9 are shown in Table 9-1. The parameters of each lens in this optical system, such as the curvature of the object-side and image-side surfaces, the lens thickness, and the refractive index, are shown in Table 8-2. The aspherical coefficients of each surface in this optical system are shown in Tables 9-3-1 and 9-3-2. Figure 54 The diagram shows the phase diagrams of the superlens (i.e., the second lens 20) in the optical system provided in Embodiment 9 at three different wavelengths: 486.13 nm, 587.56 nm, and 656.27 nm. Figure 54 It can be seen that the phase of this optical system covers the 2π phase in different wavebands. Figure 55 An astigmatism diagram of the optical system provided in Embodiment 8 is shown. Figure 55 It can be seen that the astigmatism of this optical system is less than 0.5 mm under different fields of view. Figure 56 A distortion diagram of the optical system provided in an embodiment of this application is shown. Figure 56 It can be seen that the distortion of the optical system is less than 5% under different fields of view. Figure 57 This demonstrates that the broadband matching degree of the superlens (i.e., the second lens 20) in the optical system is greater than 90%. As can be seen from the above, the optical system provided in Embodiment 9 produces clear images with excellent control over astigmatism and distortion, resulting in superior image quality.

[0349] Table 9-1

[0350]

[0351]

[0352] Table 9-2

[0353]

[0354] Table 9-3-1

[0355]

[0356]

[0357] Table 9-3-2

[0358] Surface number <![CDATA[L 5o ]]> <![CDATA[L 5i ]]> <![CDATA[L 6o ]]> <![CDATA[L 6i ]]> K 1.8911075 -8.95372 -0.28186 -55836.57 A -0.102315 -0.148997 0.0384629 -0.067803 B 0.000209 0.1388092 0.0008724 0.0261372 C -0.180969 -0.125707 0.0093502 -0.009002 D 0.3159076 0.0685821 -0.003484 0.0011236 E -0.176353 -0.015608 -0.000976 -8.63E-05 F 0.0334863 0.0010858 9.34E-06 5.41E-05 G 0.0017692 -0.000596 0.0001875 -1.47E-05

[0359] Example 10

[0360] This application provides an exemplary optical system, such as... Figure 8 As shown, the optical system includes components along the object-to-image axis (…). Figure 8 The first lens 10, the aperture stop (STO), the second lens 20, the third lens 30, the fourth lens 40, the fifth lens 50, and the sixth lens 60 are arranged sequentially from left to right. Optionally, as... Figure 8 As shown, an infrared filter is also disposed between the sixth lens 60 and the image plane of the optical system. The optical system provided in this application embodiment satisfies formulas (1-1) to (1-4):

[0361] f / EPD < 3; (1-1)

[0362] 25°≤HFOV≤55°; (1-2)

[0363] 0.05mm≤d2≤2mm; (1-3)

[0364] |f²| / f≥10; (1-4)

[0365] Where f is the focal length of the optical system; EPD is the entrance pupil diameter of the optical system; HFOV is half of the maximum field of view of the optical system; d2 is the thickness of the second lens 20; and f2 is the focal length of the second lens 20.

[0366] The specific parameters of the optical system provided in Example 10 are shown in Table 10-1. The parameters of each lens in this optical system, such as the curvature of the object-side and image-side surfaces, the lens thickness, and the refractive index, are shown in Table 8-2. The aspherical coefficients of each surface in this optical system are shown in Tables 10-3-1 and 10-3-2. Figure 58 The diagram shows the phase diagrams of the superlens (i.e., the second lens 20) in the optical system provided in Embodiment 10 at three different wavelengths: 486.13 nm, 587.56 nm, and 656.27 nm. Figure 58 It can be seen that the phase of this optical system covers the 2π phase in different wavebands. Figure 59An astigmatism diagram of the optical system provided in Embodiment 10 is shown. Figure 59 It can be seen that the astigmatism of this optical system is less than 0.5 mm under different fields of view. Figure 60 A distortion diagram of the optical system provided in an embodiment of this application is shown. Figure 60 It can be seen that the distortion of the optical system is less than 5% under different fields of view. Figure 61 The broadband matching degree of the superlens (i.e., the second lens 20) in the optical system is shown. Figure 61 In this example, the broadband matching degree of the superlens is greater than 90%. As can be seen from the above, the optical system provided in Example 10 produces clear images with excellent control over astigmatism and distortion, resulting in superior image quality.

[0367] Table 10-1

[0368] Parameter Items numerical values Operating band (WL) VIS (400-700nm) Equivalent Focal Length (EFL) 4mm Field of view (2ω) 66.4° F number 2.85 Like high (ImgH) 3.014mm Total system length (TTL) 4.2mm

[0369] Table 10-2

[0370]

[0371]

[0372] Table 10-3-1

[0373] Surface number <![CDATA[L 1o ]]> <![CDATA[L 1i ]]> <![CDATA[L 3o ]]> <![CDATA[L 3i ]]> <![CDATA[L 4o ]]> <![CDATA[L 4i ]]> K -4.930885 -9.967591 -2.48E+16 -9.967591 -19.73647 -21.66745 A 0.2816075 -0.03333 -0.056678 -0.03333 -0.130666 -0.061622 B -0.219687 -0.00782 0.2996243 -0.00782 0.0049981 -0.093319 C 0.2763091 -0.154566 0.1635329 -0.154566 0.3531215 0.1416254 D -0.239358 0.3416499 -0.823191 0.3416499 -0.519927 0.1471917 E 0.0782505 -0.331173 0.6670421 -0.331173 0.3548887 0.1339349 F 0.1286909 0.020975 -0.71871 0.020975 0.1946845 -0.387356 G -0.204236 2.69E-09 -2.83E-07 2.69E-09 0.1440297 0.2628043

[0374] Table 10-3-2

[0375]

[0376]

[0377] Example 11

[0378] This application provides an exemplary optical system, such as... Figure 9 As shown, the optical system includes components along the object-to-image axis (…). Figure 9 The aperture stop (STO), first lens 10, second lens 20, third lens 30, fourth lens 40, fifth lens 50, and sixth lens 60 are arranged sequentially from left to right. Optionally, as... Figure 9 As shown, an infrared filter is also disposed between the sixth lens 60 and the image plane of the optical system. The optical system provided in this application embodiment satisfies formulas (1-1) to (1-4):

[0379] f / EPD < 3; (1-1)

[0380] 25°≤HFOV≤55°; (1-2)

[0381] 0.05mm≤d2≤2mm; (1-3)

[0382] |f²| / f≥10; (1-4)

[0383] Where f is the focal length of the optical system; EPD is the entrance pupil diameter of the optical system; HFOV is half of the maximum field of view of the optical system; d2 is the thickness of the second lens 20; and f2 is the focal length of the second lens 20.

[0384] The specific parameters of the optical system provided in Example 11 are shown in Table 11-1. The parameters of each lens in this optical system, such as the curvature of the object-side and image-side surfaces, the lens thickness, and the refractive index, are shown in Table 8-2. The aspherical coefficients of each surface in this optical system are shown in Tables 11-3-1 and 11-3-2. Figure 62 The diagram shows the phase diagrams of the superlens (i.e., the second lens 20) in the optical system provided in Embodiment 11 at three different wavelengths: 486.13 nm, 587.56 nm, and 656.27 nm. Figure 62 It can be seen that the phase of this optical system covers the 2π phase in different wavebands. Figure 63 An astigmatism diagram of the optical system provided in Embodiment 11 is shown. Figure 63 It can be seen that the astigmatism of this optical system is less than 0.5 mm under different fields of view. Figure 64 A distortion diagram of the optical system provided in an embodiment of this application is shown. Figure 64 It can be seen that the distortion of the optical system is less than 5% under different fields of view. Figure 65 The broadband matching degree of the superlens (i.e., the second lens 20) in this optical system is shown. Figure 65 In this example, the broadband matching degree of the superlens is greater than 90%. As can be seen from the above, the optical system provided in Example 11 produces clear images with excellent control over astigmatism and distortion, resulting in superior image quality.

[0385] Table 11-1

[0386] Parameter Items numerical values Operating band (WL) VIS (400-700nm) Equivalent Focal Length (EFL) 3.9mm Field of view (2ω) 74.4° F number 2.85 Like high (ImgH) 2.96mm Total system length (TTL) 3.7mm

[0387] Table 11-2

[0388]

[0389]

[0390] Table 11-3-1

[0391] Surface number <![CDATA[L 1o ]]> <![CDATA[L 1i ]]> <![CDATA[L 3o ]]> <![CDATA[L 3i ]]> <![CDATA[L 4o ]]> <![CDATA[L 4i ]]> K -6.921265 6080.8108 -6.16E+13 -0.778323 -289.2003 13.501261 A 0.2485578 -0.044799 0.1043122 0.1166528 -0.120811 -0.113485 B -0.351313 -0.062043 0.1195529 0.1301479 0.0133244 0.0304691 C 0.3233402 -0.176557 0.2924759 0.1003042 0.4990614 0.260482 D -0.384073 0.2848269 -0.885858 -0.285371 -0.456855 -0.015974 E 0.1111747 -0.234164 1.4033469 0.3671659 0.1759116 0.0192984 F 0.1334113 0.1277366 -0.754863 -0.098758 -0.111425 -0.018539 G -0.403389 -0.182789 0.014783 0.454752 -0.03331 -0.074472

[0392] Table 11-3-2

[0393]

[0394] Example 12

[0395] This application provides an exemplary optical system, such as... Figure 10 As shown, the optical system includes components along the object-to-image axis (…). Figure 10 The aperture stop (STO), first lens 10, second lens 20, third lens 30, fourth lens 40, fifth lens 50, and sixth lens 60 are arranged sequentially from left to right. Optionally, as... Figure 10 As shown, an infrared filter is also disposed between the sixth lens 60 and the image plane of the optical system. The optical system provided in this application embodiment satisfies formulas (1-1) to (1-4):

[0396] f / EPD < 3; (1-1)

[0397] 25°≤HFOV≤55°; (1-2)

[0398] 0.05mm≤d2≤2mm; (1-3)

[0399] |f²| / f≥10; (1-4)

[0400] Where f is the focal length of the optical system; EPD is the entrance pupil diameter of the optical system; HFOV is half of the maximum field of view of the optical system; d2 is the thickness of the second lens 20; and f2 is the focal length of the second lens 20.

[0401] The specific parameters of the optical system provided in Example 12 are shown in Table 12-1. The parameters of each lens in this optical system, such as the curvature of the object-side and image-side surfaces, the lens thickness, and the refractive index, are shown in Table 12-2. The aspherical coefficients of each surface in this optical system are shown in Tables 12-3-1 and 12-3-2. Figure 66 The diagram shows the phase diagrams of the superlens (i.e., the second lens 20) in the optical system provided in Embodiment 6 at three different wavelengths: 486.13 nm, 587.56 nm, and 656.27 nm. Figure 66 It can be seen that the phase of this optical system covers the 2π phase in different wavebands. Figure 67 An astigmatism diagram of the optical system provided in Embodiment 12 is shown. Figure 67 It can be seen that the astigmatism of this optical system is less than 0.5 mm under different fields of view. Figure 68 A distortion diagram of the optical system provided in an embodiment of this application is shown. Figure 68 It can be seen that the distortion of the optical system is less than 5% under different fields of view. Figure 69 The broadband matching degree of the superlens (i.e., the second lens 20) in this optical system is shown. Figure 69In this example, the broadband matching degree of the superlens is greater than 90%. As can be seen from the above, the optical system provided in Example 12 produces clear images with excellent control over astigmatism and distortion, resulting in superior image quality.

[0402] Table 12-1

[0403]

[0404]

[0405] Table 12-2

[0406]

[0407] Table 12-3-1

[0408]

[0409]

[0410] Table 12-3-2

[0411] Surface number <![CDATA[L 5o ]]> <![CDATA[L 5i ]]> <![CDATA[L 6o ]]> <![CDATA[L 6i ]]> K -15.04539 -5.696009 -2.780013 -113.4115 A -0.146435 -0.087964 0.001517 -0.016554 B 0.1148561 0.1642436 -0.040839 -0.004933 C -0.195972 -0.125797 0.0074632 -0.007158 D 0.2916657 0.0665997 -0.001059 0.0024146 E -0.175865 -0.01712 0.000584 -0.000212 F 0.027464 0.0005325 0.000378 6.71E-06 G -0.003683 -0.000604 -0.00012 -6.90E-06

[0412] Thirdly, embodiments of this application also provide an imaging device, which includes the optical system provided in any of the above embodiments and a photosensitive element disposed on the image plane of the aforementioned optical system. Preferably, the photosensitive element is an electronic photosensitive element, such as a charge-coupled device (CCD) and a complementary metal-oxide-semiconductor (CMOS).

[0413] Fourthly, embodiments of this application also provide an electronic device, which includes the imaging device provided in the above embodiments.

[0414] It should be noted that the superlens provided in any embodiment of this application can be processed by semiconductor technology, and has the advantages of being lightweight, thin, simple in structure and process, low in cost and high in mass production consistency.

[0415] In summary, the optical system provided in this application provides the main optical power by setting the first lens as an aspherical refractive lens, setting the second lens as a superlens, setting the remaining lenses as refractive lenses, and ensuring that at least one of the surfaces of the third to sixth lenses is aspherical. Furthermore, by employing a layout that satisfies f / EPD < 3; 25° ≤ HFOV ≤ 55°; 0.05mm ≤ d2 ≤ 2mm, the system length and weight of the six-element optical system are reduced while maintaining image quality, thus promoting miniaturization and weight reduction of the optical system.

[0416] The imaging device provided in this application uses the optical system provided in this application. Compared with traditional optical systems, the optical system has a smaller size, lighter weight, and excellent imaging quality. It is beneficial to combine the optical system with larger sensors and can also reduce the installation space occupied by the optical system in the imaging device, thereby promoting the miniaturization and weight reduction of the imaging device.

[0417] The electronic device provided in this application embodiment employs the imaging device provided in this application embodiment. Because the optical system provided in this application embodiment has a smaller size, lighter weight, and superior imaging quality compared to traditional optical systems, it facilitates the integration of the optical system with larger sensors and reduces the installation space occupied by the optical system in the imaging device and electronic device. Therefore, the electronic device provided in this application embodiment, by employing this imaging device, reduces the size and weight of the imaging device in the electronic device, promoting miniaturization and weight reduction of the electronic device.

[0418] The above description is merely a specific implementation of the embodiments of this application, but the protection scope of the embodiments of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the embodiments of this application should be included within the protection scope of the embodiments of this application. Therefore, the protection scope of the embodiments of this application should be determined by the protection scope of the claims.

Claims

1. An optical system, characterized in that, The optical system includes a first lens (10), a second lens (20), a third lens (30), a fourth lens (40), a fifth lens (50), and a sixth lens (60) arranged sequentially from the object side to the image side. Wherein, the first lens (10) is an aspherical refractive lens; the second lens (20) is a superlens; the remaining lenses are all refractive lenses, and all surfaces of the third lens (30), the fourth lens (40), the fifth lens (50) and the sixth lens (60) include at least one aspherical surface, the aspherical surface containing a point of inflection; The first lens (10) has positive optical power, and the object-side surface of the first lens (10) is convex; the image-side surface of the second lens (20) has an infinite radius of curvature; the object-side surface of the third lens (30) is curved; the image-side surface of the third lens (30) is convex; the object-side surface of the fourth lens (40) is concave; the object-side surfaces of the fifth lens (50) and the sixth lens (60) both have negative radii of curvature. The optical system must satisfy at least the following relationship: ； ； ； ； ； Where f is the focal length of the optical system; EPD is the entrance pupil diameter of the optical system; HFOV is half of the maximum field of view of the optical system; d2 is the thickness of the second lens (20); f2 is the focal length of the second lens (20); and TTL is the distance from the object-side surface of the first lens (10) to the imaging surface of the optical system.

2. The optical system as described in claim 1, characterized in that, The optical system also satisfies the following relationship: ； in, f1 is the radius of curvature of the object-side surface of the first lens (10); f1 is the focal length of the first lens (10).

3. The optical system as described in claim 1, characterized in that, The optical system also satisfies: ； Wherein, V1 is the Abbe number of the first lens (10); V3 is the Abbe number of the third lens (30); and V4 is the Abbe number of the fourth lens (40).

4. The optical system as claimed in claim 1, characterized in that, The optical system also satisfies: ； Wherein, ImgH is the maximum imaging height of the optical system; TTL is the distance from the object-side surface of the first lens (10) to the imaging surface of the optical system.

5. The optical system as claimed in claim 1, characterized in that, The optical system also satisfies the following: the image-side surface of the fourth lens (40) is concave, and, ； in, The radius of curvature of the object-side surface of the fourth lens (40); The radius of curvature of the image-side surface of the fourth lens (40).

6. The optical system as claimed in claim 1, characterized in that, The radius of curvature of the image-side surface of the fifth lens (50) is less than zero.

7. The optical system as claimed in claim 1, characterized in that, The optical system also satisfies: ； Where f1 is the focal length of the first lens (10); f is the focal length of the optical system.

8. The optical system as claimed in claim 1, characterized in that, Any one or more of the third lens (30), the fourth lens (40), the fifth lens (50) and the sixth lens (60) are aspherical refractive lenses.

9. The optical system as described in any one of claims 1-8, characterized in that, The superlens includes a base layer (201) and at least one nanostructure layer (202) disposed on one side of the base layer (201). Wherein, any of the nanostructure layers (202) comprises periodically arranged nanostructures (2021). The substrate layer (201) and the nanostructure layer (202) are configured to transmit radiation in the operating wavelength range of the optical system.

10. The optical system as claimed in claim 9, characterized in that, The superlens comprises at least two nanostructure layers (202); In this case, the nanostructures in any two adjacent nanostructure layers (202) are arranged coaxially.

11. The optical system as claimed in claim 9, characterized in that, The superlens includes at least two nanostructure layers (202); wherein the nanostructures in any adjacent nanostructure layers (202) are staggered along a direction parallel to the substrate of the superlens.

12. The optical system as claimed in claim 9, characterized in that, The arrangement period of the nanostructure (2021) is greater than or equal to 0.3λ. c And less than or equal to 2λ c , where λ c The wavelength is the center wavelength of the operating band of the optical system.

13. The optical system as claimed in claim 9, characterized in that, The height of the nanostructure (2021) is greater than or equal to 0.3λ. c And less than or equal to 2λ c , where λ c The wavelength is the center wavelength of the operating band of the optical system.

14. The optical system as claimed in claim 9, characterized in that, The material of the base layer (201) includes any one or more of fused silica, quartz glass, crown glass, flint glass, sapphire, and alkaline glass.

15. The optical system as claimed in claim 9, characterized in that, The materials of the nanostructure (2021) include any one or more of fused silica, quartz glass, crown glass, flint glass, sapphire, crystalline silicon, amorphous silicon, and hydrogenated amorphous silicon.

16. The optical system as claimed in claim 9, characterized in that, The nanostructure (2021) is made of the same material as the substrate (201).

17. The optical system as claimed in claim 9, characterized in that, The nanostructure (2021) and the substrate (201) are made of different materials.

18. The optical system as claimed in claim 9, characterized in that, The superlens also includes a filler (2022); The filler (2022) is filled between the nanostructures (2021); the extinction coefficient of the filler (2022) for the operating wavelength of the optical system is less than 0.

01.

19. The optical system as claimed in claim 18, characterized in that, The absolute value of the difference between the refractive index of the filler (2022) and the refractive index of the nanostructure (2021) is greater than or equal to 0.

5.

20. The optical system as claimed in claim 18, characterized in that, The filler (2022) is made of any one or more of the following materials: air, fused silica, quartz glass, crown glass, flint glass, sapphire, crystalline silicon, amorphous silicon, and hydrogenated amorphous silicon.

21. The optical system as claimed in claim 18, characterized in that, The material of the filler (2022) is different from the material of the nanostructure (2021).

22. The optical system as claimed in claim 18, characterized in that, The material of the filler (2022) is different from the material of the base layer (201).

23. The optical system as claimed in claim 9, characterized in that, The superlens also includes an anti-reflective coating (203); Wherein, the antireflective film (203) is disposed on the side of the nanostructure layer (202) adjacent to air; and / or, The antireflective membrane (203) is disposed on the side of the substrate layer (201) away from the nanostructure layer (202).

24. The optical system as claimed in claim 9, characterized in that, The nanostructure (2021) is periodically arranged in the form of superstructural units (2023); The superstructure unit (2023) has a densely packed pattern, and the nanostructure (2021) is located at the vertices and / or center of the densely packed pattern.

25. The optical system as claimed in claim 24, characterized in that, The shape of the superstructure unit (2023) includes one or more combinations of sector, square, and hexagon.

26. The optical system as claimed in claim 9, characterized in that, The shape of the nanostructure (2021) is polarization insensitive.

27. The optical system as claimed in claim 26, characterized in that, The shape of the nanostructure (2021) includes one or more combinations of cylindrical, hollow cylindrical, circular hole, hollow circular hole, square column, square hole, hollow square column and hollow square hole.

28. The optical system as claimed in claim 9, characterized in that, The phase of the superlens also satisfies: ； ； ； ； ； ； ； ； Where r is the distance from the center of the superlens to any nanostructure; λ is the operating wavelength of the superlens; φ0 is any phase related to the operating wavelength of the superlens; (x, y) are the mirror coordinates of the superlens; f2 is the focal length of the superlens; a i and b i The coefficients are real numbers.

29. The optical system as claimed in claim 8, characterized in that, The optical system operates in the visible light band and the near-infrared band.

30. An imaging device, characterized in that, The imaging device includes: The optical system as described in any one of claims 1-29 and the photosensitive element disposed on the image plane of the optical system.

31. An electronic device, characterized in that, The electronic device includes the imaging apparatus as described in claim 30.

Images