Visible light optical system and visible light optical lens

Abstract

The invention discloses a visible light optical system and a visible light optical lens. The visible light optical system comprises a super lens, a first aspheric lens, a second aspheric lens, a third aspheric lens and a fourth aspheric lens. The first aspheric lens, the second aspheric lens, the third aspheric lens and the fourth aspheric lens are sequentially arranged from the object side to the image side along the optical axis. The focal power of the super lens is positive; the focal power of the first aspheric lens is positive, and the object side surface and the image side surface of the first aspheric lens both protrude towards the object side; the focal power of the second aspheric lens is negative, and the object side surface and the image side surface of the second aspheric lens both protrude towards the image side; the focal power of the third aspheric lens is positive, the object side face and the image side face of the third aspheric lens both protrude towards the image side, and the focal power of the fourth aspheric lens is negative. According to the visible light optical system, the super lens is combined with the traditional refraction lens, so that the visible light optical system has the advantages of low cost, small size and excellent imaging quality.

Description

Technical Field

[0001] This application relates to the field of optical systems, and in particular, to a visible light optical system and a visible light optical lens. Background Art

[0002] As the market's requirements for the imaging quality of optical systems are getting higher and higher, in the prior art, methods such as gluing and separating positive and negative lenses are usually adopted to correct aberrations to improve the imaging quality of optical systems. However, the above methods will cause problems such as a larger volume, a larger number of lenses, and a higher cost of the optical system, making the optical system not advantageous in terms of volume, cost, etc.

[0003] Therefore, there is an urgent need to provide an optical system with a small volume, low cost, and excellent imaging quality through optimized design. Summary of the Invention

[0004] In view of the above technical problems, an embodiment of this application provides a visible light optical system and a visible light optical lens, aiming to provide an optical system with a small volume, low cost, and excellent imaging quality.

[0005] According to one aspect of the embodiment of this application, a visible light optical system is disclosed. The visible light optical system includes: a meta-lens, a first aspherical lens, a second aspherical lens, a third aspherical lens, and a fourth aspherical lens, wherein the first aspherical lens, the second aspherical lens, the third aspherical lens, and the fourth aspherical lens are sequentially arranged along the optical axis from the object side to the image side;

[0006] The optical power of the meta-lens is positive; the optical power of the first aspherical lens is positive, the object side surface of the first aspherical lens bulges towards the object side, and the image side surface of the first aspherical lens bulges towards the object side; the optical power of the second aspherical lens is negative, the object side surface of the second aspherical lens bulges towards the image side, and the image side surface of the second aspherical lens bulges towards the image side; the optical power of the third aspherical lens is positive, the object side surface of the third aspherical lens bulges towards the image side, and the image side surface of the third aspherical lens bulges towards the image side; the optical power of the fourth aspherical lens is negative.

[0007] In some embodiments, the visible light optical system satisfies: where f is the effective focal length of the visible light optical system, and EPD is the entrance pupil diameter of the visible light optical system.

[0008] In some embodiments, the visible light optical system satisfies: Wherein, TTL is the total optical length of the visible light optical system, FOV is the maximum full field of view angle of the visible light optical system; BFL is the optical back focal length of the visible light optical system, and f is the effective focal length of the visible light optical system.

[0009] In some embodiments, the visible light optical system satisfies: Wherein, CRA is the chief ray incidence angle of the visible light optical system, ImgH is half of the diagonal length of the imaging area of the visible light optical system on the image plane, and TTL is the total optical length of the visible light optical system.

[0010] In some embodiments, the visible light optical system satisfies: Wherein, R7 is the curvature radius of the object side surface of the fourth aspherical lens, R8 is the curvature radius of the image side surface of the fourth aspherical lens, f4 is the focal length of the fourth aspherical lens, and f is the effective focal length of the visible light optical system.

[0011] In some embodiments, the visible light optical system satisfies: f1 is the focal length of the first aspherical lens, f2 is the focal length of the second aspherical lens, f3 is the focal length of the third aspherical lens, f4 is the focal length of the fourth aspherical lens, and f m is the focal length of the metalens.

[0012] In some embodiments, the metalens satisfies: 10D ≤ ΔΦ m ≤ 25D, wherein, ΔΦ m is the difference between the maximum optical power and the minimum optical power of the metalens in the working band, and D is the unit of diopter.

[0013] In some embodiments, the visible light optical system satisfies: Wherein, f is the effective focal length of the visible light optical system, is the maximum value of the absolute value of the phase provided by the metalens, r m is the maximum effective area radius of the metalens, and f m is the focal length of the metalens.

[0014] In some embodiments, the first aspherical lens, the metalens, the second aspherical lens, the third aspherical lens, and the fourth aspherical lens are arranged in sequence along the optical axis from the object side to the image side.

[0015] In some embodiments, the visible light optical system further includes a fifth aspherical lens, the fifth aspherical lens is glued to the image side surface of the metalens, and the image side surface of the fifth aspherical lens bulges toward the object side.

[0016] A second aspect of the embodiments of the present application provides a visible light optical system, which includes an image sensor and the visible light optical system described in any one of the above; the image sensor is disposed on the image plane of the visible light optical system.

[0017] The visible light optical system provided by the present application includes a meta-lens, a first aspherical lens, a second aspherical lens, a third aspherical lens, and a fourth aspherical lens. Among them, the first aspherical lens, the second aspherical lens, the third aspherical lens, and the fourth aspherical lens are sequentially arranged along the optical axis from the object side to the image side. The optical power of the meta-lens is positive; the optical power of the first aspherical lens is positive, the object side surface of the first aspherical lens bulges towards the object side, and the image side surface of the first aspherical lens bulges towards the object side; the optical power of the second aspherical lens is negative, the object side surface of the second aspherical lens bulges towards the image side, and the image side surface of the second aspherical lens bulges towards the image side; the optical power of the third aspherical lens is positive, the object side surface of the third aspherical lens bulges towards the image side, and the image side surface of the third aspherical lens bulges towards the image side; the optical power of the fourth aspherical lens is negative. The visible light optical system provided by the present application corrects the aberration of the visible light optical system by combining a meta-lens with a traditional refractive lens, so that the visible light optical system has excellent imaging quality. Since the number of lenses in the visible light optical system is small and the total optical length is short, the visible light optical system has the advantages of low cost and small volume. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] By referring to the accompanying drawings and describing its exemplary embodiments in detail, the above and other objects, features, and advantages of the present application will become more apparent.

[0019] Figure 1 FIG. shows a schematic diagram of the architecture layout of the visible light optical system in an embodiment of the present application.

[0020] Figure 2 FIG. shows the phase distribution diagram of the meta-lens of the visible light optical system in an embodiment of the present application.

[0021] Figure 3 FIG. shows the MTF field curve diagram of the meta-lens of the visible light optical system in an embodiment of the present application.

[0022] Figure 4 FIG. shows the field curvature diagram of the meta-lens of the visible light optical system in an embodiment of the present application.

[0023] Figure 5 FIG. shows the distortion diagram of the meta-lens of the visible light optical system in an embodiment of the present application.

[0024] Figure 6 FIG. shows a schematic diagram of the architecture layout of the visible light optical system in an embodiment of the present application.

[0025] Figure 7 Shows the phase distribution diagram of the metalens of the visible light optical system in an embodiment of the present application.

[0026] Figure 8 Shows the MTF field curve diagram of the metalens of the visible light optical system in an embodiment of the present application.

[0027] Figure 9 Shows the field curvature diagram of the metalens of the visible light optical system in an embodiment of the present application.

[0028] Figure 10 Shows the distortion diagram of the metalens of the visible light optical system in an embodiment of the present application.

[0029] Figure 11 Shows the schematic diagram of the architecture layout of the visible light optical system in an embodiment of the present application.

[0030] Figure 12 Shows the phase distribution diagram of the metalens of the visible light optical system in an embodiment of the present application.

[0031] Figure 13 Shows the MTF field curve diagram of the metalens of the visible light optical system in an embodiment of the present application.

[0032] Figure 14 Shows the field curvature diagram of the metalens of the visible light optical system in an embodiment of the present application.

[0033] Figure 15 Shows the distortion diagram of the metalens of the visible light optical system in an embodiment of the present application.

[0034] Figure 16 Shows the schematic diagram of the architecture layout of the visible light optical system in an embodiment of the present application.

[0035] Figure 17 Shows the phase distribution diagram of the metalens of the visible light optical system in an embodiment of the present application.

[0036] Figure 18 Shows the MTF field curve diagram of the metalens of the visible light optical system in an embodiment of the present application.

[0037] Figure 19 Shows the field curvature diagram of the metalens of the visible light optical system in an embodiment of the present application.

[0038] Figure 20 Shows the distortion diagram of the metalens of the visible light optical system in an embodiment of the present application.

[0039] Figure 21 Shows the schematic diagram of the architecture layout of the visible light optical system in an embodiment of the present application.

[0040] Figure 22 Shows the phase distribution diagram of the metalens of the visible light optical system in an embodiment of the present application.

[0041] Figure 23 Shows the MTF field curve diagram of the metalens of the visible light optical system in an embodiment of the present application.

[0042] Figure 24 Shows the field curvature diagram of the metalens of the visible light optical system in an embodiment of the present application.

[0043] Figure 25 Shows the distortion diagram of the metalens of the visible light optical system in an embodiment of the present application.

[0044] Reference numerals

[0045] 100, visible light optical system;

[0046] 10, first aspherical lens;

[0047] 20, metalens; 210, substrate; 220, micro-nano structure;

[0048] 30, second aspherical lens;

[0049] 40, third aspherical lens;

[0050] 50, fourth aspherical lens;

[0051] 60, fifth aspherical lens;

[0052] 70, aperture stop; 80, filter; 90, optical axis;

[0053] 200, object plane; 300, image plane. Detailed implementation manners

[0054] Now, example embodiments will be described more fully with reference to the accompanying drawings. However, the example embodiments can be implemented in various forms and should not be construed as limited to the examples set forth herein; rather, these example embodiments are provided so that the description of the present application will be more comprehensive and complete, and the concept of the example embodiments will be fully conveyed to those skilled in the art. The drawings are only schematic illustrations of the present application and are not necessarily drawn to scale. The same reference numerals in the drawings denote the same or similar parts, and thus their repeated description will be omitted.

[0055] In addition, the described features, structures or characteristics can be combined in one or more example embodiments in any suitable manner. In the following description, many specific details are provided to provide a full understanding of the example embodiments of the present application. However, those skilled in the art will appreciate that the technical solutions of the present application can be practiced while omitting one or more of the specific details, or other modules, components, etc. can be adopted. In other cases, known structures, methods, implementations or operations are not shown or described in detail to avoid obscuring the main content and making various aspects of the present application vague.

[0056] This application provides a visible light optical system 100, see Figure 1 , Figure 1 A schematic diagram of the structural layout of a visible light optical system 100 in one embodiment of the present application is shown, wherein the image formed by the visible light optical system 100 is located on the right side of the rightmost lens, the right side of the rightmost lens being the image side of the visible light optical system 100, and the image plane 300 being located on the image side; the left side of the leftmost lens of the visible light optical system 100 being the object side of the visible light optical system 100, and the object plane 200 being located on the object side. Therefore, the direction from the object side to the image side along the optical axis 90 is consistent with the direction from the object plane 200 to the image plane 300 along the optical axis 90. At the same time, for ease of description, the side of each optical element in the visible light optical system 100 that is closest to the object side is referred to as the object side surface of the optical element, and the side of each optical element in the visible light optical system 100 that is closest to the image side is referred to as the image side surface of the optical element. For example, the surface of the metalens 20 that is closest to the image side is referred to as the image side surface of the metalens 20.

[0057] Please refer again Figure 1 The visible light optical system 100 includes a metalens 20, a first aspheric lens 10, a second aspheric lens 30, a third aspheric lens 40, and a fourth aspheric lens 50, wherein the first aspheric lens 10, the second aspheric lens 30, the third aspheric lens 40, and the fourth aspheric lens 50 are arranged in sequence from the object side to the image side along the optical axis 90. The position of the metalens 20 is not fixed, and the metalens 20 can be arranged between any two adjacent lenses, that is, the metalens 20 can be arranged between the first aspheric lens 10 and the second aspheric lens 30, or the metalens 20 can be arranged between the second aspheric lens 30 and the third aspheric lens 40, or the metalens 20 can be arranged between the third aspheric lens 40 and the fourth aspheric lens 50.

[0058] The optical power of the super lens 20 is positive, and the super lens 20 includes a substrate 210 and a micro-nano structure 220. The micro-nano structure 220 is a sub-wavelength structure, and the micro-nano structure 220 is disposed on the object side and / or image side of the substrate 210. Figure 1 、 Figure 6 、 Figure 11 and Figure 21, in some embodiments, the micro-nano structure 220 is disposed on the object side of the substrate 210; please refer to Figure 16 , in some embodiments, the micro-nano structure 220 is disposed on the image side of the substrate 210.

[0059] By configuring the parameters of the micro-nano structure 220, the metalens 20 can have target performance. The metalens 20 has different optical powers at different wavelengths. By reasonably arranging the micro-nano structure 220, the effect of achromatism over a wide spectrum can be achieved. At the same time, the optical power of the metalens 20 at each wavelength can correct the aberration of the visible light optical system 100.

[0060] It should be noted that the number of metalenses 20 included in the visible light optical system 100 is not limited to one. That is, two or more metalenses of other specifications (different from the metalens 20 provided in this application) can be used to achieve the target phase gradient, so that the visible light optical system 100 has the expected optical performance.

[0061] The first aspherical lens 10 has a positive optical power. The object side of the first aspherical lens 10 bulges toward the object side, and the image side of the first aspherical lens 10 bulges toward the object side.

[0062] The second aspherical lens 30 has a negative optical power. The object side of the second aspherical lens 30 bulges toward the image side, and the image side of the second aspherical lens 30 bulges toward the image side.

[0063] The third aspherical lens 40 has a positive optical power. The object side of the third aspherical lens 40 bulges toward the image side, and the image side of the third aspherical lens 40 bulges toward the image side. The fourth aspherical lens 50 has a negative optical power.

[0064] The visible light optical system 100 provided in this application corrects the aberration of the visible light optical system 100 by combining the metalens 20 with a traditional refractive lens, so that the visible light optical system 100 has excellent imaging quality. Since the number of lenses in the visible light optical system 100 is small and the total optical length is short, the visible light optical system 100 has the advantages of low cost and small volume.

[0065] Please refer to Figure 1 、 Figure 6 、 Figure 11 、 Figure 16 and Figure , in some embodiments, the paraxial region of the object side of the fourth aspherical lens 50 bulges toward the image side, and the paraxial region of the image side of the fourth aspherical lens 50 bulges toward the object side. Herein, the paraxial region in this application refers to an extremely narrow region where the angle between the light ray and the optical axis 90 is extremely small during the propagation process and is only distributed near the optical axis 90.

[0066] Please refer to again ​ 、​ , ​ , ​ and ​ , in some embodiments, the image side of the fourth aspherical lens 50 has an inflection point.

[0067] Please refer to ​ , ​ , ​ , ​ and ​ , in some embodiments, the visible light optical system 100 includes a superlens 20, a first aspherical lens 10, a second aspherical lens 30, a third aspherical lens 40, and a fourth aspherical lens 50. Among them, the first aspherical lens 10, the superlens 20, the second aspherical lens 30, the third aspherical lens 40, and the fourth aspherical lens 50 are sequentially arranged along the optical axis 90 from the object side to the image side.

[0068] In some embodiments, the visible light optical system 100 further includes a fifth aspherical lens 60. The positive and negative of the focal length of the fifth aspherical lens 60 are not completely consistent in different embodiments, that is, the focal length of the fifth aspherical lens 60 is positive and negative in different embodiments. The fifth aspherical lens 60 is glued to the superlens 20 to form a glued lens group, which can make the visible light optical system 100 have a higher design freedom.

[0069] Specifically, the fifth aspherical lens 60 is glued to the image side of the substrate 210 of the superlens 20, and the image side of the fifth aspherical lens 60 bulges toward the object side. Since the fifth aspherical lens 60 is glued to the superlens 20, the position of the fifth aspherical lens 60 in the optical system depends on the position of the superlens 20 in the visible light optical system 100.

[0070] Furthermore, please refer to ​ and ​ , in some embodiments, the visible light optical system 100 further includes a fifth aspherical lens 60, among which the first aspherical lens 10, the superlens 20, the fifth aspherical lens 60, the second aspherical lens 30, the third aspherical lens 40, and the fourth aspherical lens 50 are sequentially arranged along the optical axis 90 from the object side to the image side, so that the visible light optical system 100 has excellent imaging quality.

[0071] Even further, please refer to ​ , in some embodiments, when the first aspherical lens 10, the superlens 20, the fifth aspherical lens 60, the second aspherical lens 30, the third aspherical lens 40, and the fourth aspherical lens 50 are sequentially arranged along the optical axis 90 from the object side to the image side, the micro-nano structure 220 is provided on the image side of the substrate 210.

[0072] Even further, please refer to ​, in some embodiments, when the first aspherical lens 10, the metalens 20, the fifth aspherical lens 60, the second aspherical lens 30, the third aspherical lens 40, and the fourth aspherical lens 50 are arranged in sequence along the optical axis 90 from the object side to the image side, the micro-nano structure 220 is disposed on the object side surface of the substrate 210, and the fifth aspherical lens 60 is glued to the image side surface of the substrate 210. Since the micro-nano structure 220 and the fifth aspherical lens 60 are respectively located on both sides of the substrate 210, the two sides of the substrate 210 can be processed separately during processing, which is convenient for the processing of the metalens 20 and the fifth aspherical lens 60.

[0073] Furthermore, in some embodiments, when the first aspherical lens 10, the metalens 20, the fifth aspherical lens 60, the second aspherical lens 30, the third aspherical lens 40, and the fourth aspherical lens 50 are arranged in sequence along the optical axis 90 from the object side to the image side, the micro-nano structure 220 is disposed on the object side surface and the image side surface of the substrate 210, so that the metalens 20 has a higher design freedom.

[0074] In some embodiments, the visible light optical system 100 further includes a fifth aspherical lens 60. The material of the fifth aspherical lens 60 is photoresist. By coating photoresist on the metalens 20 and using a lithography process to process the coated photoresist, the surface of the photoresist away from the substrate 210 is processed into a target shape, and thus the fifth aspherical lens 60 can be obtained.

[0075] Specifically, please refer to ​ , when the micro-nano structure 220 and the fifth aspherical lens 60 are respectively located on both sides of the substrate 210, photoresist can be directly coated on the side surface where the substrate 210 is glued to the fifth aspherical lens 60, and the photoresist is processed to obtain a glued lens group formed by gluing the metalens 20 and the fifth aspherical lens 60. Please refer to ​ , when the micro-nano structure 220 and the fifth aspherical lens 60 are respectively located on the same side of the substrate 210, after the processing of the micro-nano structure 220 is completed, the micro-nano structure 220 is filled, photoresist is coated on the filled interface, and the photoresist is processed to obtain a glued lens group formed by gluing the metalens 20 and the fifth aspherical lens 60.

[0076] Since the metalens 20 can be manufactured by a lithography process, the processing processes of the metalens 20 and the fifth aspherical lens 60 are mutually compatible. After the processing of the metalens 20 is completed, the fifth aspherical lens 60 can be processed on the basis of the metalens 20 to obtain a glued lens group formed by gluing the metalens 20 and the fifth aspherical lens 60. The processing process of the fifth aspherical lens 60 provided in this application has the advantages of convenience and fewer steps compared with the process of separately processing the metalens 20 and the fifth aspherical lens 60 and then gluing them.

[0077] In some embodiments, the visible light optical system 100 satisfies Conditional Formula 1: Wherein, f is the effective focal length of the visible light optical system 100, and EPD (Entrance Pupil Diameter, hereinafter referred to as EPD) is the entrance pupil diameter of the visible light optical system 100. f and EPD have the same dimension, both being length units, such as millimeters.

[0078] Conditional Formula 1 reflects the range of the F-number of the visible light optical system 100. From Conditional Formula 1, it can be seen that the F-number of the visible light optical system 100 is small, and the visible light optical system 100 has a large light input amount, thereby ensuring that the image formed by the visible light optical system 100 is relatively clear and bright.

[0079] In some embodiments, the visible light optical system 100 satisfies Conditional Formula 2: Wherein, FOV (Field of View, hereinafter referred to as FOV) is the maximum full field of view angle of the visible light optical system 100, and the unit of FOV is degree. TTL (Total Track Length, hereinafter referred to as TTL) is the total optical length of the visible light optical system 100, BFL (Back focal length, hereinafter referred to as BFL) is the optical back focal length of the visible light optical system 100, and f is the effective focal length of the visible light optical system 100. TTL, BFL, and f have the same dimension, both being length units, such as millimeters.

[0080] Conditional Formula 2 can ensure that the visible light optical system 100 has a small total optical length on the premise of meeting the target specifications, and further can ensure that the visible light optical system 100 has a small volume.

[0081] In some embodiments, the visible light optical system 100 satisfies Conditional Formula 3: Wherein, CRA (Chief Ray Angle, CRA) is the chief ray incident angle of the visible light optical system 100, and the unit of CRA is degree. ImgH is half of the diagonal length of the imaging area of the visible light optical system 100 on the image plane 300, that is, ImgH is the image height of the visible light optical system 100. TTL is the total optical length of the visible light optical system 100. ImgH and TTL have the same dimension, both being length units, such as millimeters.

[0082] Conditional Formula 3 characterizes the contribution of the chief ray incident angle to the volume compression in the system. The lower limit of Conditional Formula 3 represents the maximum total optical length that can be achieved when the constraint of the chief ray incident angle is released, and the upper limit of Conditional Formula 3 represents the maximum volume compression ability provided by the chief ray incident angle.

[0083] In some embodiments, the visible light optical system 100 satisfies Conditional Formula 4: Among them, R7 is the curvature radius of the object side of the fourth aspherical lens 50, R8 is the curvature radius of the image side of the fourth aspherical lens 50, f4 is the focal length of the fourth aspherical lens 50, and f is the effective focal length of the visible light optical system 100. R7, R8, f4, and f have the same dimension, which is a length unit, such as millimeter.

[0084] Conditional formula four is used to ensure that the fourth aspherical lens 50 has sufficient light deflection ability, and at the same time, it also ensures that the fourth aspherical lens 50 has a reasonable shape, so that the fourth aspherical lens 50 has good processability.

[0085] In some embodiments, the visible light optical system 100 satisfies conditional formula five: f1 is the focal length of the first aspherical lens 10, f2 is the focal length of the second aspherical lens 30, f3 is the focal length of the third aspherical lens 40, f4 is the focal length of the fourth aspherical lens 50, and f m is the focal length of the meta-lens 20. f1, f2, f3, f4, and f m have the same dimension, which is a length unit, such as millimeter.

[0086] The lower limit of conditional formula five can avoid the meta-lens 20 from being unable to be manufactured due to excessive optical power, and the upper limit of conditional formula five can ensure that the meta-lens 20 can correct chromatic aberration in the visible light optical system 100.

[0087] In some embodiments, the meta-lens 20 satisfies conditional formula six: 10D ≤ ΔΦ m ≤ 25D, where ΔΦ m is the difference between the maximum optical power and the minimum optical power of the meta-lens 20 in the working band, and D (Diopter, abbreviated as D) is the unit of diopter, D = m -1 .

[0088] Conditional formula six reflects the chromatic aberration correction ability of the meta-lens 20. The lower limit of conditional formula six represents the minimum chromatic aberration correction requirement of the entire visible light optical system 100 and its specific lens arrangement and structure for the meta-lens 20, and the upper limit of conditional formula six represents the maximum chromatic aberration correction ability that the meta-lens 20 can provide in the visible light optical system 100.

[0089] In some embodiments, the visible light optical system 100 satisfies conditional formula seven: Among them, is the maximum value of the absolute value of the phase provided by the meta-lens 20, and the unit of is rad; if the object side and the image side of the substrate 210 are both provided with micro-nano structures 220, and at this time the meta-lens 20 is a double-sided meta-lens, then the larger one of the maximum phase values provided by the object side and the image side of the meta-lens 20 is selected as f is the effective focal length of the visible light optical system 100, fm is the focal length of the metalens 20. r m is the radius of the maximum effective area of the metalens 20. The radius of the maximum effective area of the metalens 20 refers to the radius of the maximum light-transmitting area of the metalens 20. Whether the metalens 20 is a double-sided metalens or a single-sided metalens, the larger value between the radius of the maximum light-transmitting area on the object side of the metalens 20 and the radius of the maximum light-transmitting area on the image side of the metalens 20 is selected as r m . f, f m , r m have the same dimension, which is a length unit, such as millimeters.

[0090] Conditional expression seven represents the spatial phase provided by the metalens 20 per unit radius. The upper limit of conditional expression seven represents the maximum spatial phase per unit radius that the metalens 20 can provide in the visible light optical system. The lower limit of conditional expression seven represents the minimum spatial phase per unit radius that the metalens 20 needs to provide to achieve the target optical performance and compress the volume in the visible light optical system 100.

[0091] In some embodiments, the visible light optical system 100 satisfies conditional expression eight: where V2 is the Abbe number of the second aspherical lens 30, V3 is the Abbe number of the third aspherical lens 40, and V4 is the Abbe number of the fourth aspherical lens 50.

[0092] The visible light optical system 100 satisfying conditional expression eight helps to balance the chromatic aberration of the visible light optical system 100 and can improve the imaging resolution of the visible light optical system 100.

[0093] The visible light optical system 100 further includes a diaphragm 70. The diaphragm 70 is used to control the light input amount of the visible light optical system 100 to ensure that the visible light optical system 100 can work effectively and generate high-quality images. The diaphragm 70 is disposed in the optical path of the visible light optical system 100.

[0094] In some embodiments, when the visible light optical system 100 includes a metalens 20, a first aspherical lens 10, a second aspherical lens 30, a third aspherical lens 40, and a fourth aspherical lens 50, the diaphragm 70 can be disposed at the following positions: (1) The diaphragm 70 is disposed on the object side of the first aspherical lens 10, and the diaphragm 70 is spaced apart from the first aspherical lens 10; (2) Please refer to ​ , ​ , ​ and ​ , the diaphragm 70 is disposed on the object side surface of the first aspherical lens 10, that is, the diaphragm 70 is disposed in contact with the object side surface of the first aspherical lens 10; (3) The diaphragm 70 is disposed on the image side surface of the first aspherical lens 10, that is, the diaphragm 70 is disposed in contact with the image side surface of the first aspherical lens 10; (4) Please refer to​ , the aperture 70 is arranged between the first aspheric lens 10 and the super lens 20, and the aperture 70 has a target distance from the first aspheric lens 10 and the super lens 20; (5) the aperture 70 is arranged on the object side of the super lens 20, that is, the aperture 70 is attached to the object side of the super lens 20; (6) the aperture 70 is arranged on the image side of the super lens 20, that is, the aperture 70 is attached to the image side of the super lens 20; (7) the aperture 70 is arranged between the super lens 20 and the second aspheric lens 30, and the aperture 70 has a target distance from the super lens 20 and the second aspheric lens 30; (8) the aperture 70 is arranged on the object side of the second aspheric lens 30, that is, the aperture 70 is attached to the object side of the second aspheric lens 30; (9) the aperture 70 is arranged on the image side of the second aspheric lens 30, that is, the aperture 70 is attached to the image side of the second aspheric lens 30 side arrangement; (10) the aperture 70 is arranged between the second aspheric lens 30 and the third aspheric lens 40, and the aperture 70 has a target distance from the second aspheric lens 30 and the third aspheric lens 40; (11) the aperture 70 is arranged on the object side of the third aspheric lens 40, that is, the aperture 70 is attached to the object side of the third aspheric lens 40; (12) the aperture 70 is arranged on the image side of the third aspheric lens 40, that is, the aperture 70 is attached to the image side of the third aspheric lens 40; (13) the aperture 70 is arranged between the third aspheric lens 40 and the fourth aspheric lens 50, and the aperture 70 has a target distance from the third aspheric lens 40 and the fourth aspheric lens 50; (14) the aperture 70 is arranged on the object side of the third aspheric lens 40, that is, the aperture 70 is attached to the object side of the third aspheric lens 40.

[0095] In some embodiments, the visible light optical system 100 includes a metalens 20, a first aspheric lens 10, a second aspheric lens 30, a third aspheric lens 40, a fourth aspheric lens 50, and a fifth aspheric lens 60, and when the metalens 20 and the fifth aspheric lens 60 are glued together to form a glued lens group, the aperture 70 can be set at the following positions: (1) the aperture 70 is set on the object side of the first aspheric lens 10, and the aperture 70 is spaced apart from the first aspheric lens 10; (2) refer to ​ 、 ​ 、 ​ and ​ , the aperture 70 is arranged on the object side of the first aspheric lens 10, that is, the aperture 70 is attached to the object side of the first aspheric lens 10; (3) the aperture 70 is arranged on the image side of the first aspheric lens 10, that is, the aperture 70 is attached to the image side of the first aspheric lens 10; (4) please refer to ​, the aperture stop 70 is disposed between the first aspherical lens 10 and the cemented lens group, and the aperture stop 70 has a target distance from both the first aspherical lens 10 and the cemented lens group; (5) the aperture stop 70 is disposed on the object side of the cemented lens group, that is, the aperture stop 70 is disposed in contact with the object side of the cemented lens group; (6) the aperture stop 70 is disposed on the image side of the cemented lens group, that is, the aperture stop 70 is disposed in contact with the image side of the cemented lens group; (7) the aperture stop 70 is disposed between the cemented lens group and the second aspherical lens 30, and the aperture stop 70 has a target distance from both the cemented lens group and the second aspherical lens 30; (8) the aperture stop 70 is disposed on the object side of the second aspherical lens 30, that is, the aperture stop 70 is disposed in contact with the object side of the second aspherical lens 30; (9) the aperture stop 70 is disposed on the image side of the second aspherical lens 30, that is, the aperture stop 70 is disposed in contact with the image side of the second aspherical lens 30; (10) the aperture stop 70 is disposed between the second aspherical lens 30 and the third aspherical lens 40, and the aperture stop 70 has a target distance from both the second aspherical lens 30 and the third aspherical lens 40; (11) the aperture stop 70 is disposed on the object side of the third aspherical lens 40, that is, the aperture stop 70 is disposed in contact with the object side of the third aspherical lens 40; (12) the aperture stop 70 is disposed on the image side of the third aspherical lens 40, that is, the aperture stop 70 is disposed in contact with the image side of the third aspherical lens 40; (13) the aperture stop 70 is disposed between the third aspherical lens 40 and the fourth aspherical lens 50, and the aperture stop 70 has a target distance from both the third aspherical lens 40 and the fourth aspherical lens 50; (14) the aperture stop 70 is disposed on the object side of the third aspherical lens 40, that is, the aperture stop 70 is disposed in contact with the object side of the third aspherical lens 40.

[0096] Please refer to ​ , ​ , ​ , ​ and ​ , in some embodiments, the visible light optical system 100 further includes a filter 80, the filter 80 is located between the fourth aspherical lens 50 and the image plane 300, and the filter 80 is configured to filter light in other wavelength bands except visible light.

[0097] The visible light optical system 100 provided by the present application has the following advantages:

[0098] (1) The overall optical length is less than 3.1 mm;

[0099] (2) At a spatial frequency of 100 lp / mm, the MTF (Modulation Transfer Function, abbreviated as MTF) is greater than 0.35 within the full field of view.

[0100] Exemplarily, five visible light optical systems 100 that meet the usage requirements are provided in five embodiments of this application. Next, a detailed introduction to the visible light optical systems 100 provided in each embodiment of this application will be given.

[0101] Embodiment 1

[0102] ​ The schematic diagram of the architecture layout of the visible light optical system 100 provided in Embodiment 1 of this application is shown. ​ In the visible light optical system 100, along the optical axis 90 from the object surface 200 to the image surface 300, it successively includes: a diaphragm 70, a first aspherical lens 10, a meta-lens 20, a second aspherical lens 30, a third aspherical lens 40, a fourth aspherical lens 50, and a filter 80. Some parameters of the visible light optical system 100 provided in Embodiment 1 are shown in Table 1-1.

[0103] Table 1-1. Some parameters of the visible light optical system 100 provided in Embodiment 1

[0104] ​ ​ ​ ​ ​ 90° ​ 2.18 ​ ​ ​ ​

[0105] As can be seen from Table 1-1, the overall optical length of the visible light optical system 100 is relatively short, only 2.453 mm. The volume of the visible light optical system 100 provided in Embodiment 1 is relatively small and can be installed in various relatively thin and light electronic products. The F-number of the visible light optical system 100 is 2.18, and the light input amount of the visible light optical system 100 is relatively large, which can ensure that the formed image is relatively clear and bright. Along the direction of the optical axis 90 from the object surface 200 to the image surface 300, starting from the diaphragm 70, each surface in the visible light optical system 100 is numbered, and after summarizing the parameters of each surface, the following Table 1-2 is obtained.

[0106] Table 1-2. Parameters of each surface in the visible light optical system 100 provided in Embodiment 1

[0107]

[0108]

[0109] For each of the surfaces in Table 1-2, surface 1 is the aperture stop 70, surface 2 is the object side surface of the first aspherical lens 10, and surface 3 is the image side surface of the first aspherical lens 10. Surface 4 is the image side surface of the metalens 20. Since the micro-nano structure 220 is provided on the image side surface of the substrate 210, surface 4 is denoted as the structured surface. Surface 5 is the image side surface of the metalens 20. Surface 6 is the object side surface of the second aspherical lens 30, and surface 7 is the image side surface of the second aspherical lens 30. Surface 8 is the object side surface of the third aspherical lens 40, and surface 9 is the image side surface of the third aspherical lens 40. Surface 10 is the object side surface of the fourth aspherical lens 50, and surface 11 is the image side surface of the fourth aspherical lens 50. Surface 12 is the object side surface of the filter 80, and surface 13 is the image side surface of the filter 80. Surface 14 is the image plane 300.

[0110] Combined with ​As can be seen from Table 1-2, the radius of curvature of Surface 1 is infinite, that is, Surface 1 is a plane. The distance between Surface 1 and Surface 2 is -1.9E-01 mm. The negative sign in "-1.9E-01" indicates that the vertex of Surface 2 protrudes towards the object side beyond Surface 1. The radius of curvature of Surface 2 is 7.0E-01 mm. The distance between Surface 2 and Surface 3 is 2.7E-01 mm. The refractive index and Abbe number of the material between Surface 2 and Surface 3 are 1.54 and 56 respectively. The radius of curvature of Surface 3 is 1.5E+00 mm. The distance between Surface 2 and Surface 3 is 1.1E-01 mm. The material between Surface 3 and Surface 4 is air. The radius of curvature of Surface 4 is infinite, that is, Surface 4 is a plane. The distance between Surface 4 and Surface 5 is 2.0E-01 mm. The refractive index and Abbe number of the material between Surface 4 and Surface 5 are 1.46 and 67.8 respectively. The radius of curvature of Surface 5 is infinite, that is, Surface 5 is a plane. The distance between Surface 5 and Surface 6 is 8.3E-02 mm. The material between Surface 5 and Surface 6 is air. The radius of curvature of Surface 6 is -5.0E+00 mm. The distance between Surface 6 and Surface 7 is 1.9E-01 mm. The refractive index and Abbe number of the material between Surface 6 and Surface 7 are 1.66 and 20.4 respectively. The radius of curvature of Surface 7 is -5.8E+00 mm. The distance between Surface 7 and Surface 8 is 2.2E-01 mm. The material between Surface 7 and Surface 8 is air. The radius of curvature of Surface 8 is -1.3E+00 mm. The distance between Surface 8 and Surface 9 is 2.5E-01 mm. The refractive index and Abbe number of the material between Surface 8 and Surface 9 are 1.54 and 56 respectively. The radius of curvature of Surface 9 is -6.2E-01 mm. The distance between Surface 9 and Surface 10 is 1.0E-01 mm. The material between Surface 9 and Surface 10 is air. The radius of curvature of Surface 10 is -7.9E+00 mm. The distance between Surface 10 and Surface 11 is 3.2E-01 mm. The refractive index and Abbe number of the material between Surface 10 and Surface 11 are 1.54 and 56 respectively. The radius of curvature of Surface 11 is 9.0E-01 mm. The distance between Surface 11 and Surface 12 is 1.1E-01 mm. The material between Surface 11 and Surface 12 is air. The radius of curvature of Surface 12 is infinite, that is, Surface 12 is a plane. The distance between Surface 12 and Surface 13 is 1.1E-01 mm. The refractive index and Abbe number of the material between Surface 12 and Surface 13 are 1.52 and 54.5 respectively. The radius of curvature of Surface 13 is infinite, that is, Surface 13 is a plane. The distance between Surface 13 and Surface 14 is 4.9E-01 mm. The material between Surface 13 and Surface 14 is air.

[0111] Surfaces 2, 3, 6, 7, 8, 9, 10, and 11 are all even aspherical surfaces, and their surface profiles satisfy the following relationship:

[0112]

[0113] Among them, Z(r) is the distance sag from the vertex of the aspheric surface at the position with height r along the optical axis 90 direction of the aspheric surface; c is the surface curvature of the aspheric surface, c = 1 / R, and R is the radius of curvature of the aspheric surface; k is the conic coefficient; A, B, C, D... are the aspheric coefficients. The values of K, A, B, C, D... of surfaces 2, 3, 6, 7, 8, 9, 10, and 11 can be obtained by querying Table 1-3.

[0114] Table 1-3. Coefficients of Each Order of Even Aspheric Surfaces in the Visible Light Optical System 100 Provided in Embodiment 1

[0115]

[0116] Please refer to Table 1-3. For surface 2, K is -2.4E+01, A is 6.1E+00, B is -5.7E+01, C is 4.2E+02, D is -1.9E+03, E is 4.5E+03, F is -2.6E+03, G is -1.1E+04, H is 2.0E+04, and I is 1.7E+03. The values of K, A, B, C, D... of surfaces 3, 6, 7, 8, 9, 10, and 11 can be obtained by querying Table 1-3 with reference to surface 2, and will not be elaborated here one by one.

[0117] Please refer to ​ , ​ which shows the phase distribution diagram of the metalens 20 of the visible light optical system 100 provided in Embodiment 1. ​ The horizontal axis in it represents the distance from the center of the metalens 20, and the unit is millimeter; ​ the vertical axis in it represents the phase, and the unit is 2πrad. It can be known from ​ that the maximum value of the absolute value of the phase provided by the metalens 20 is 34.671rad. It is worth mentioning that ​ what is given is the actual phase distribution of the metalens 20 in Embodiment 1. Since the phase is a periodic function about 2π, that is, there is a relational expression (n is an integer), therefore, the phase of the metalens 20 in Embodiment 1 can be modulo 2π as needed based on ​ to achieve normalization processing to meet the actual processing needs of the metalens 20.

[0118] Please refer to ​ , ​ which shows the MTF field of view curve diagram of the visible light optical system 100 provided in Embodiment 1. ​ The abscissa in it is the X-axis field of view angle, and its unit is degree;​ The ordinate in ​ lists the sagittal curve S1 and meridional curve T1 of the MTF varying with the field of view at a spatial frequency of 50 lp / mm, and the sagittal curve S2 and meridional curve T2 of the MTF varying with the field of view at a spatial frequency of 100 lp / mm. From ​ it can be seen that within the field of view of 0.9 (40.5°), the MTF is greater than 0.5, and within the field of view of 1.0 (45°), the MTF is greater than 0.48. The imaging quality of the visible light optical system 100 is excellent.

[0119] Please refer to ​ , ​ which shows the field curvature diagram of the visible light optical system 100 provided in Embodiment 1. ​ The horizontal axis in ​ is the field curvature, and its unit is millimeter; ​ the vertical axis in ​ shows the sagittal field curvature S and meridional field curvature T of the visible light optical system 100 at visible light wavelengths of 0.650 μm, 0.610 μm, 0.555 μm, 0.510 μm, and 0.470 μm. Since some curves are too dense, the wavelengths corresponding to each curve are not distinguished in this embodiment. From

[0120] Please refer to ​ , ​ which shows the distortion of the visible light optical system 100 provided in Embodiment 1 at visible light wavelengths of 0.650 μm, 0.610 μm, 0.555 μm, 0.510 μm, and 0.470 μm. Since the 5 curves almost completely overlap, the wavelengths corresponding to each curve are not distinguished in this embodiment. From ​ it can be seen that the maximum distortion of the visible light optical system 100 provided in Embodiment 1 at the above wavelengths is 2.66%, and the distortion is small.

[0121] Embodiment 2

[0122] ​ shows a schematic diagram of the architecture layout of the visible light optical system 100 provided in Embodiment 2 of the present application. ​The visible light optical system 100 sequentially includes, along the optical axis 90 from the object surface 200 to the image surface 300: a diaphragm 70, a first aspherical lens 10, a meta-lens 20, a fifth aspherical lens 60, a second aspherical lens 30, a third aspherical lens 40, a fourth aspherical lens 50, and a filter 80. Among them, the optical power of the fifth aspherical lens 60 is positive, and the fifth aspherical lens 60 is glued to the meta-lens 20 to form a glued lens group. Some parameters of the visible light optical system 100 provided in Embodiment 2 are shown in Table 2-1.

[0123] Table 2-1. Some parameters of the visible light optical system 100 provided in Embodiment 2

[0124] ​ ​ ​ ​ ​ 93° ​ 2.19 ​ ​ ​ ​

[0125] As can be seen from Table 2-1, the overall optical length of the visible light optical system 100 is relatively short, only 2.4437 mm. The volume of the visible light optical system 100 provided in Embodiment 2 is relatively small and can be installed in various relatively thin and light electronic products. The F number of the visible light optical system 100 is 2.19, and the light incident amount of the visible light optical system 100 is relatively large, which can ensure that the formed image is relatively clear and bright. Along the direction of the optical axis 90 from the object surface 200 to the image surface 300, starting from the diaphragm 70, each surface in the visible light optical system 100 is numbered, and after summarizing the parameters of each surface, the following Table 2-2 is obtained.

[0126] Table 2-2. Parameters of each surface in the visible light optical system 100 provided in Embodiment 2

[0127]

[0128]

[0129] For the analysis of each surface in Table 2-2, reference can be made to Embodiment 1, and details will not be elaborated in this embodiment.

[0130] Surfaces 2, 3, 6, 7, 8, 9, 10, 11, and 12 are all even aspherical surfaces, and their surface shapes satisfy the following relational expression:

[0131]

[0132] Among them, Z(r) is the distance sagitta from the vertex of the aspherical surface at the position with a height of r along the optical axis 90 direction; c is the curvature of the aspherical surface, c = 1 / R, and R is the radius of curvature of the aspherical surface; k is the conic coefficient; A, B, C, D... are aspherical coefficients. The values of K, A, B, C, D... of surfaces 2, 3, 6, 7, 8, 9, 10, 11, and 12 can be queried from Table 2-3.

[0133] Table 2-3. Coefficients of each order of even aspheres in the visible light optical system 100 provided in Example 2

[0134]

[0135] The values of K, A, B, C, D... of surfaces 2, 3, 6, 7, 8, 9, 10, 11, and 12 can be queried from Table 2-3 and will not be elaborated here one by one.

[0136] Please refer to ​ , ​ which shows the phase distribution diagram of the metalens 20 of the visible light optical system 100 provided in Example 2. ​ The horizontal axis in it represents the distance from the center of the metalens 20, and the unit is millimeter; ​ the vertical axis in it represents the phase, and the unit is 2πrad. As can be seen from ​ , the maximum value of the absolute value of the phase provided by the metalens 20 is 35.739rad. It is worth mentioning that ​ what is given is the actual phase distribution of the metalens 20 in Example 2. Since the phase is a periodic function of 2π, that is, there is a relational expression (n is an integer), therefore, the phase of the metalens 20 in Example 2 can be modulo 2π as needed based on ​ to achieve normalization processing to meet the actual processing needs of the metalens 20.

[0137] Please refer to ​ , ​ which shows the MTF field curve graph of the visible light optical system 100 provided in Example 2. ​ The abscissa in it is the X-axis field angle, and its unit is degree; ​ the ordinate in it is the MTF value. ​ It lists the sagittal curve S1 and meridional curve T1 of the MTF varying with the field of view at a spatial frequency of 50 lp / mm, and the sagittal curve S2 and meridional curve T2 of the MTF varying with the field of view at a spatial frequency of 100 lp / mm. As can be seen from ​ , within the range of 0.9 field of view (46.5°), the MTF is greater than 0.5, and within the range of 1.0 field of view (46.5°), the MTF is greater than 0.35. The imaging quality of the visible light optical system 100 is excellent.

[0138] Please refer to ​ , ​ which shows the field curvature graph of the visible light optical system 100 provided in Example 2. ​ The horizontal axis in it is the field curvature, and its unit is millimeter; ​The vertical axis in the middle is the Y-axis field of view, and its unit is degree. ​ The sagittal field curvature S and the meridional field curvature T of the visible light optical system 100 are respectively shown under visible light with wavelengths of 0.650 μm, 0.610 μm, 0.555 μm, 0.510 μm, and 0.470 μm. Since some curves are too dense, the wavelengths corresponding to each curve are not distinguished in this embodiment. ​ It can be seen that the maximum field curvature of the visible light optical system 100 provided in Embodiment 2 in the sagittal direction at the above wavelengths is 0.115 mm, and the maximum field curvature of the visible light optical system 100 in the meridional direction at the above wavelengths is 0.202 mm. The field curvature is small and meets the requirements for field curvature in the excellent imaging quality standard.

[0139] Please refer to ​ , ​ The distortion of the visible light optical system 100 provided in Embodiment 2 is shown under visible light with wavelengths of 0.650 μm, 0.610 μm, 0.555 μm, 0.510 μm, and 0.470 μm. Since the five curves almost completely overlap, the wavelengths corresponding to each curve are not distinguished in this embodiment. ​ It can be seen that the maximum distortion of the visible light optical system 100 provided in Embodiment 2 at the above wavelengths is 2.05%, and the distortion is small.

[0140] Embodiment 3

[0141] ​ The schematic diagram of the architecture layout of the visible light optical system 100 provided in Embodiment 3 of the present application is shown. ​ In the visible light optical system 100 along the optical axis 90 from the object surface 200 to the image surface 300, it successively includes: a diaphragm 70, a first aspherical lens 10, a meta-lens 20, a second aspherical lens 30, a third aspherical lens 40, a fourth aspherical lens 50, and a filter 80. Some parameters of the visible light optical system 100 provided in Embodiment 3 are shown in Table 3-1.

[0142] Table 3-1. Some parameters of the visible light optical system 100 provided in Embodiment 3

[0143] ​ ​ ​ ​ ​ 90° ​ 2.20 ​ ​ ​ ​

[0144] As can be seen from Table 3-1, the total optical length of the visible light optical system 100 is relatively short, only 2.88 mm. The volume of the visible light optical system 100 provided in Embodiment 3 is relatively small and can be installed in various relatively thin and light electronic products. The F number of the visible light optical system 100 is 2.20, and the amount of incident light of the visible light optical system 100 is relatively large, which can ensure that the formed image is relatively clear and bright. Along the optical axis 90 from the object surface 200 to the image surface 300 direction, starting from the aperture stop 70, each surface in the visible light optical system 100 is numbered, and after summarizing the parameters of each surface, the following Table 3-2 is obtained.

[0145] Table 3-2. Parameters of each surface in the visible light optical system 100 provided in Embodiment 3

[0146]

[0147] For the analysis of each surface in Table 3-2, reference can be made to Embodiment 1, and details will not be repeated in this embodiment.

[0148] Surfaces 2, 3, 6, 7, 8, 9, 10, and 11 are all even aspherical surfaces, and their surface profiles satisfy the following relationship:

[0149]

[0150] Among them, Z(r) is the distance sag from the vertex of the aspherical surface at the position with a height of r along the optical axis 90 direction; c is the surface curvature of the aspherical surface, c = 1 / R, and R is the radius of curvature of the aspherical surface; k is the conic coefficient; A, B, C, D... are the aspherical coefficients. The values of K, A, B, C, D... of surfaces 2, 3, 6, 7, 8, 9, 10, and 11 can be queried from Table 1-3.

[0151] Table 3-3. Coefficients of each order of the even aspherical surfaces in the visible light optical system 100 provided in Embodiment 3

[0152]

[0153] The values of K, A, B, C, D... of surfaces 2, 3, 6, 7, 8, 9, 10, and 11 can be queried from Table 3-3, and will not be elaborated one by one here.

[0154] Please refer to ​ , ​ which shows the phase distribution diagram of the metalens 20 of the visible light optical system 100 provided in Embodiment 2. ​ The horizontal axis in it represents the distance from the center of the metalens 20, with the unit of millimeter; ​ the vertical axis in it represents the phase, with the unit of 2πrad. From​ It can be seen that the maximum value of the absolute value of the phase provided by the metalens 20 is 53.068 rad. It is worth mentioning that ​ what is given is the actual phase distribution of the metalens 20 in Embodiment 2. Since the phase is a periodic function of 2π, that is, there is a relational expression (n is an integer), therefore, according to the need, based on ​ the phase of the metalens 20 in Embodiment 2 is taken modulo 2π to achieve normalization processing to meet the actual processing needs of the metalens 20.

[0155] Please refer to ​ , ​ which shows the MTF field curve diagram of the visible light optical system 100 provided in Embodiment 3. ​ The abscissa in ​ is the X-axis field angle, and its unit is degree; ​ The ordinate in ​ is the MTF value. The sagittal curve S1 and meridional curve T1 of the MTF varying with the field of view at a spatial frequency of 50 lp / mm, and the sagittal curve S2 and meridional curve T2 of the MTF varying with the field of view at a spatial frequency of 100 lp / mm are listed in

[0156] Please refer to ​ , ​ which shows the field curvature diagram of the visible light optical system 100 provided in Embodiment 3. ​ The horizontal axis in ​ is the field curvature, and its unit is millimeter; ​ The vertical axis in ​ is the Y-axis field of view, and its unit is degree. The sagittal field curvature S and meridional field curvature T of the visible light optical system 100 at wavelengths of 0.650 μm, 0.610 μm, 0.555 μm, 0.510 μm, and 0.470 μm visible light are respectively shown in

[0157] Please refer to ​ , ​The distortion of the visible light optical system 100 provided in Embodiment 3 at visible light wavelengths of 0.650 μm, 0.610 μm, 0.555 μm, 0.510 μm, and 0.470 μm is shown. Since the five curves almost completely overlap, the wavelengths corresponding to each curve are not distinguished in this embodiment. From ​ it can be seen that the maximum distortion of the visible light optical system 100 provided in Embodiment 3 at the above wavelengths is 2.57%, and the distortion is relatively small.

[0158] Embodiment 4

[0159] ​ The schematic diagram of the architecture layout of the visible light optical system 100 provided in Embodiment 4 of the present application is shown. ​ In the visible light optical system 100, along the optical axis 90 from the object surface 200 to the image surface 300, it successively includes: a diaphragm 70, a first aspherical lens 10, a meta-lens 20, a fifth aspherical lens 60, a second aspherical lens 30, a third aspherical lens 40, a fourth aspherical lens 50, and a filter 80. Among them, the optical power of the fifth aspherical lens 60 is negative, and the fifth aspherical lens 60 is glued to the meta-lens 20 to form a glued lens group. Some parameters of the visible light optical system 100 provided in Embodiment 4 are shown in Table 4-1.

[0160] Table 4-1. Some parameters of the visible light optical system 100 provided in Embodiment 4

[0161]

[0162]

[0163] As can be seen from Table 4-1, the overall optical length of the visible light optical system 100 is relatively short, only 2.4678 mm. The volume of the visible light optical system 100 provided in Embodiment 4 is relatively small and can be installed in various relatively thin and light electronic products. The F-number of the visible light optical system 100 is 2.19, and the light input amount of the visible light optical system 100 is relatively large, which can ensure that the formed image is relatively clear and bright. Along the direction of the optical axis 90 from the object surface 200 to the image surface 300, starting from the diaphragm 70, each surface in the visible light optical system 100 is numbered, and after summarizing the parameters of each surface, the following Table 4-2 is obtained.

[0164] Table 4-2. Parameters of each surface in the visible light optical system 100 provided in Embodiment 4

[0165]

[0166] For the analysis of each surface in Table 4-2, reference can be made to Embodiment 1, and details will not be repeated in this embodiment.

[0167] Surfaces 2, 3, 6, 7, 8, 9, 10, 11, and 12 are all even aspherical surfaces, and their surface profiles satisfy the following relationship:

[0168]

[0169] Among them, Z(r) is the distance sag from the vertex of the aspherical surface along the optical axis 90 direction at a position with a height of r; c is the surface curvature of the aspherical surface, c = 1 / R, and R is the radius of curvature of the aspherical surface; k is the conic coefficient; A, B, C, D... are the aspherical coefficients. The values of K, A, B, C, D... of surfaces 2, 3, 6, 7, 8, 9, 10, 11, and 12 can be obtained by querying Table 2-3.

[0170] Table 4-3. Coefficients of each order of the even aspherical surfaces in the visible light optical system 100 provided in Example 4

[0171]

[0172] The values of K, A, B, C, D... of surfaces 2, 3, 6, 7, 8, 9, 10, 11, and 12 can be obtained by querying Table 4-3, and will not be elaborated here one by one.

[0173] Please refer to ​ , ​ which shows the phase distribution diagram of the metalens 20 of the visible light optical system 100 provided in Example 4. ​ The horizontal axis in ​ represents the distance from the center of the metalens 20, and the unit is millimeter; ​ The vertical axis in represents the phase, and the unit is 2πrad. It can be seen from ​ that the maximum value of the absolute value of the phase provided by the metalens 20 is 27.238rad. It is worth mentioning that ​ shows the actual phase distribution of the metalens 20 in Example 4. Since the phase is a periodic function of 2π, that is, there is a relationship

[0174] Please refer to ​ , ​ which shows the MTF field of view curve diagram of the visible light optical system 100 provided in Example 4. ​ The abscissa in is the X-axis field of view angle, and its unit is degree; ​ The ordinate in is the MTF value. ​The sagittal curve S1 and meridional curve T1 of the MTF varying with the field of view at a spatial frequency of 50 lp / mm are listed, as well as the sagittal curve S2 and meridional curve T2 of the MTF varying with the field of view at a spatial frequency of 100 lp / mm. From ​ it can be seen that within the field of view of 0.9 (40.5°), the MTF is greater than 0.52, and within the field of view of 1.0 (45°), the MTF is greater than 0.39. The imaging quality of the visible light optical system 100 is excellent.

[0175] Please refer to ​ , ​ which shows the field curvature diagram of the visible light optical system 100 provided in Embodiment 4. ​ In it, the horizontal axis is the field curvature, and its unit is millimeter; ​ in it, the vertical axis is the field of view of the Y axis, and its unit is degree. ​ It respectively shows the sagittal field curvature S and meridional field curvature T of the visible light optical system 100 under visible light with wavelengths of 0.650 μm, 0.610 μm, 0.555 μm, 0.510 μm, and 0.470 μm. Since some curves are too dense, the wavelengths corresponding to each curve are not distinguished in this embodiment. From ​ it can be seen that the maximum sagittal field curvature of the visible light optical system 100 provided in Embodiment 4 at the above wavelengths is 0.064 mm, and the maximum meridional field curvature of the visible light optical system 100 at the above wavelengths is 0.108 mm. The field curvature is small, meeting the requirements for field curvature in the excellent imaging quality standard.

[0176] Please refer to ​ , ​ which shows the distortion of the visible light optical system 100 provided in Embodiment 4 under visible light with wavelengths of 0.650 μm, 0.610 μm, 0.555 μm, 0.510 μm, and 0.470 μm. Since the five curves almost completely overlap, the wavelengths corresponding to each curve are not distinguished in this embodiment. From ​ it can be seen that the maximum distortion of the visible light optical system 100 provided in Embodiment 4 at the above wavelengths is 2.99%, and the distortion is small.

[0177] Embodiment 5

[0178] ​ It shows a schematic diagram of the architecture layout of the visible light optical system 100 provided in Embodiment 5 of the present application, ​ in which the visible light optical system 100 along the optical axis 90 from the object surface 200 to the image surface 300 sequentially includes: a first aspherical lens 10, a diaphragm 70, a meta-lens 20, a second aspherical lens 30, a third aspherical lens 40, a fourth aspherical lens 50, and a filter 80. Some parameters of the visible light optical system 100 provided in Embodiment 5 are shown in Table 5-1.

[0179] Table 5-1. Partial parameters of the visible light optical system 100 provided in Example 5

[0180] ​ ​ ​ ​ ​ 90° ​ 2.18 ​ ​ ​ ​

[0181] As can be seen from Table 5-1, the total optical length of the visible light optical system 100 is relatively short, only 3.05 mm. The volume of the visible light optical system 100 provided in Example 5 is relatively small and can be installed in various thin and light electronic products. The F number of the visible light optical system 100 is 2.18, and the light input amount of the visible light optical system 100 is relatively large, which can ensure that the formed image is relatively clear and bright. Along the optical axis 90 from the object surface 200 to the image surface 300 direction, starting from the aperture stop 70, each surface in the visible light optical system 100 is numbered, and after summarizing the parameters of each surface, the following Table 5-2 is obtained.

[0182] Table 5-2. Parameters of each surface in the visible light optical system 100 provided in Example 5

[0183]

[0184] For the analysis of each surface in Table 5-2, reference can be made to Example 1, and this example will not be elaborated here.

[0185] Surfaces 1, 2, 6, 7, 8, 9, 10, and 11 are all even aspherical surfaces, and their surface shapes satisfy the following relationship:

[0186]

[0187] Among them, Z(r) is the distance sagitta from the vertex of the aspherical surface at the position with a height of r along the optical axis 90 direction; c is the surface curvature of the aspherical surface, c = 1 / R, and R is the radius of curvature of the aspherical surface; k is the conic coefficient; A, B, C, D... are the aspherical coefficients. The values of K, A, B, C, D... of Surfaces 1, 2, 6, 7, 8, 9, 10, and 11 can be queried from Table 5-3.

[0188] Table 5-3. Coefficients of each order of the even aspherical surfaces in the visible light optical system 100 provided in Example 5

[0189]

[0190]

[0191] The values of K, A, B, C, D... of Surfaces 1, 2, 6, 7, 8, 9, 10, and 11 can be queried from Table 5-3, and will not be elaborated one by one here.

[0192] Please refer to ​ , ​ which shows the phase distribution diagram of the metalens 20 of the visible light optical system 100 provided in Embodiment 5. ​ The horizontal axis in it represents the distance from the center of the metalens 20, with the unit of millimeter; ​ the vertical axis in it represents the phase, with the unit of 2πrad. It can be seen from ​ that the maximum value of the absolute value of the phase provided by the metalens 20 is 29.198rad. It is worth mentioning that ​ what is given is the actual phase distribution of the metalens 20 in Embodiment 5. Since the phase is a periodic function of 2π, that is, there is a relational expression (n is an integer), therefore, the phase of the metalens 20 in Embodiment 5 can be modulo 2π as needed ​ to achieve normalization processing to meet the actual processing needs of the metalens 20.

[0193] Please refer to ​ , ​ which shows the MTF field curve diagram of the visible light optical system 100 provided in Embodiment 5. ​ The abscissa in it is the X-axis field angle, and its unit is degree; ​ the ordinate in it is the MTF value. ​ It lists the sagittal curve S1 and meridional curve T1 of the MTF varying with the field for the spatial frequency of 50lp / mm, and the sagittal curve S2 and meridional curve T2 of the MTF varying with the field for the spatial frequency of 100lp / mm. It can be seen from ​ that within the field of view of 0.9 (40.5°), the MTF is greater than 0.48, and within the field of view of 1.0 (45°), the MTF is greater than 0.42. The imaging quality of the visible light optical system 100 is excellent.

[0194] Please refer to ​ , ​ which shows the field curvature diagram of the visible light optical system 100 provided in Embodiment 5. ​ The horizontal axis in it is the field curvature, and its unit is millimeter; ​ the vertical axis in it is the Y-axis field of view, and its unit is degree. ​ It respectively shows the sagittal field curvature S and meridional field curvature T of the visible light optical system 100 under visible light with wavelengths of 0.650 μm, 0.610 μm, 0.555 μm, 0.510 μm, and 0.470 μm. Since some curves are too dense, the wavelengths corresponding to each curve are not distinguished in this embodiment. It can be seen from ​It can be known that the maximum field curvature of the visible light optical system 100 provided in Embodiment 5 in the sagittal direction at the above wavelength is 0.056 mm, and the maximum field curvature of the visible light optical system 100 in the meridional direction at the above wavelength is 0.290 mm. The field curvature is small, meeting the requirements for field curvature in the excellent imaging quality standard.

[0195] Please refer to ​ , ​ which shows the distortion of the visible light optical system 100 provided in Embodiment 5 under visible light with wavelengths of 0.650 μm, 0.610 μm, 0.555 μm, 0.510 μm, and 0.470 μm. Since the five curves almost completely overlap, the wavelengths corresponding to each curve are not distinguished in this embodiment. It can be ​ known that the maximum distortion of the visible light optical system 100 provided in Embodiment 5 at the above wavelength is 2.72%, and the distortion is small.

[0196] After summarizing the various parameters of the visible light optical system 100 provided in the above 5 embodiments, Table 6 as shown below is obtained. The display of Table 6 is mainly used to illustrate that the various conditions met by the visible light optical system 100 provided in this application are all experimentally verified and supported.

[0197] Table 6. Various parameters of the visible light optical system 100 provided in each embodiment

[0198]

[0199]

[0200] This application also provides a visible light optical lens (not shown in the figure). The visible light optical system 100 includes an image sensor and the above visible light optical system 100. Among them, the architecture of the visible light optical system 100 can be referred to above and will not be elaborated here. The image sensor is disposed on the image plane 300 of the visible light optical system 100. The image sensor includes, but is not limited to, CMOS (Complementary Metal Oxide Semiconductor, abbreviated as CMOS, complementary metal oxide semiconductor) and CCD (Charge Coupled Device, abbreviated as CCD, charge coupled device).

[0201] Since the visible light optical system 100 provided in this application has a relatively small volume and excellent image quality, it is ensured that the visible light optical lens provided in this application also has a small volume and excellent imaging quality. Therefore, the visible light optical lens can be widely applied to various electronic products, including but not limited to relatively thin and light electronic products such as mobile phones, computers, and tablet computers.

[0202] Other embodiments of the present application will be readily apparent to those skilled in the art upon consideration of the specification and practice of the invention disclosed herein. This application is intended to cover any variations, uses, or adaptations of the present application that follow the general principles of the present application and include known common general knowledge or conventional technical means in the technical field not disclosed in the present application. The specification and examples are only to be considered as exemplary, and the true scope and spirit of the present application are pointed out by the appended claims.

Claims

1. A visible light optical system, characterized in that, The visible light optical system includes: a metalens, a first aspherical lens, a second aspherical lens, a third aspherical lens, and a fourth aspherical lens, wherein the first aspherical lens, the second aspherical lens, the third aspherical lens, and the fourth aspherical lens are sequentially arranged along the optical axis from the object side to the image side; The metalens has a positive optical power; the first aspherical lens has a positive optical power, the object side surface of the first aspherical lens bulges towards the object side, and the image side surface of the first aspherical lens bulges towards the object side; the second aspherical lens has a negative optical power, the object side surface of the second aspherical lens bulges towards the image side, and the image side surface of the second aspherical lens bulges towards the image side; the third aspherical lens has a positive optical power, the object side surface of the third aspherical lens bulges towards the image side, and the image side surface of the third aspherical lens bulges towards the image side; the fourth aspherical lens has a negative optical power.

2. The visible light optical system according to claim 1, characterized in that, The visible light optical system satisfies: where f is the effective focal length of the visible light optical system, and EPD is the entrance pupil diameter of the visible light optical system.

3. The visible light optical system according to claim 1, wherein The visible light optical system satisfies: Wherein, TTL is the total optical length of the visible light optical system, FOV is the maximum full field of view angle of the visible light optical system; BFL is the optical back focus of the visible light optical system, and f is the effective focal length of the visible light optical system.

4. The visible light optical system according to claim 1, characterized in that, The visible light optical system satisfies the following: wherein, CRA is the chief ray angle of incidence of the visible light optical system, ImgH is half of the diagonal length of the imaging area of the visible light optical system on the image plane, and TTL is the total optical length of the visible light optical system.

5. The visible light optical system according to claim 1, wherein The visible light optical system satisfies: wherein, R7 is the curvature radius of the object side surface of the fourth aspherical lens, R8 is the curvature radius of the image side surface of the fourth aspherical lens, f4 is the focal length of the fourth aspherical lens, and f is the effective focal length of the visible light optical system.

6. The visible light optical system according to claim 1, wherein The visible light optical system satisfies: f1 is the focal length of the first aspherical lens, f2 is the focal length of the second aspherical lens, f3 is the focal length of the third aspherical lens, f4 is the focal length of the fourth aspherical lens, and f m is the focal length of the metalens.

7. The visible light optical system according to claim 1, wherein: The superlens satisfies: 10D ≤ ΔΦ m ≤ 25D, where ΔΦ m is the difference between the maximum optical power and the minimum optical power of the superlens in the working band, and D is the unit of diopter.

8. The visible light optical system according to claim 1, wherein The visible light optical system satisfies: where f is the effective focal length of the visible light optical system, is the maximum value of the absolute value of the phase provided by the metalens, r m is the maximum effective area radius of the metalens, f m is the focal length of the metalens.

9. The visible light optical system according to claim 1, characterized in that, The first aspherical lens, the metalens, the second aspherical lens, the third aspherical lens, and the fourth aspherical lens are sequentially arranged along the optical axis from the object side to the image side.

10. The visible light optical system according to claim 1, wherein: The visible light optical system further includes a fifth aspherical lens, the fifth aspherical lens is glued to the image side surface of the metalens, and the image side surface of the fifth aspherical lens bulges towards the object side.

11. A visible light optical system, characterized in that, The visible light optical system includes: an image sensor and the visible light optical system according to any one of claims 1-10; the image sensor is disposed on the image plane of the visible light optical system.

Images