Far infrared optical system and far infrared optical lens

Abstract

The utility model discloses a far-infrared optical system and a far-infrared optical lens. The far-infrared optical system sequentially comprises a refractor and a super lens from an object side to an image side along an optical axis, the object side surface of the refraction lens protrudes towards the image side, and the image side surface of the refraction lens protrudes towards the image side; the super lens has positive focal power, the super lens comprises a substrate and a micro-nano structure, and the micro-nano structure is arranged on the object side surface and / or the image side surface of the substrate; wherein the far infrared optical system meets the condition that L is larger than or equal to 0.02 mm and smaller than or equal to 1 mm, and L is the distance between the image side face of the super lens and the image face of the far infrared optical system. The total optical length of the far-infrared optical system is small, so that the size of the far-infrared optical system is small. The super lens not only has the function of modulating light, but also has the function of protecting glass, so that the far-infrared optical system provided by the utility model does not need to be provided with an optical element, namely protecting glass, the integration level of the far-infrared optical system can be improved, and the volume and the production cost of the far-infrared optical system can be further reduced.

Description

Technical Field

[0001] The present application relates to the field of optical systems, and in particular, to a far-infrared optical system and a far-infrared optical lens. Background Art

[0002] Infrared rays, also known as infrared radiation, are electromagnetic waves in the infrared band with a wavelength range of 0.76 - 1000 micrometers, which is between visible light and microwaves. A far-infrared optical system refers to an optical system operating in the far-infrared light band.

[0003] In the prior art, a far-infrared optical system usually includes a relatively large number of optical elements, resulting in a low integration degree of the far-infrared optical system. Since increasing the integration degree of the far-infrared optical system can reduce the number of optical elements of the far-infrared optical system, the cost and volume of the far-infrared optical system can be reduced accordingly. Summary of the Utility Model

[0004] In view of the above technical problems, the embodiments of the present application provide a far-infrared optical system and a far-infrared optical lens, aiming to improve the integration degree of the far-infrared optical system.

[0005] According to one aspect of the embodiments of the present application, a far-infrared optical system is disclosed. The far-infrared optical system sequentially includes, along the optical axis from the object side to the image side: a refractive lens and a metasurface lens; the object side surface of the refractive lens bulges towards the image side, and the image side surface of the refractive lens bulges towards the image side; the optical power of the metasurface lens is positive, and the metasurface lens includes a substrate and a micro-nano structure, and the micro-nano structure is disposed on the object side surface and / or the image side surface of the substrate;

[0006] Wherein, the far-infrared optical system satisfies: 0.02 mm ≤ L ≤ 1 mm, where L is the distance between the image side surface of the metasurface lens and the image plane of the far-infrared optical system.

[0007] In some embodiments, the refractive lens is a spherical lens.

[0008] In some embodiments, the far-infrared optical system satisfies: Wherein, the TTL is the total optical length of the far-infrared optical system, the f s is the focal length of the refractive lens, the BFL is the back focal length of the far-infrared optical system, and the f is the effective focal length of the far-infrared optical system.

[0009] In some embodiments, the far-infrared optical system satisfies: The ImgH is the radius of the imaging area corresponding to the maximum half field of view angle on the image plane of the far-infrared optical system, the FOV is the maximum field of view angle of the far-infrared optical system, the f is the effective focal length of the far-infrared optical system, and the TTL is the total optical length of the far-infrared optical system.

[0010] In some embodiments, the far-infrared optical system satisfies: wherein, the BFL is the back focal length of the far-infrared optical system, and the CT m is the central thickness of the metalens, and the L sm is the distance between the image side of the refractive lens and the object side of the metalens on the optical axis, the f is the effective focal length of the far-infrared optical system, and the f m is the focal length of the metalens.

[0011] In some embodiments, the far-infrared optical system satisfies: wherein, the R 1 is the radius of curvature of the object side of the refractive lens, and the R 2 is the radius of curvature of the image side of the refractive lens, the r 1 is half of the effective diameter of the object side of the refractive lens, and the r 2 is half of the effective diameter of the image side of the refractive lens, the CT m is the central thickness of the metalens; the surface of the substrate provided with the micro-nano structure is the target surface, and the r m is half of the effective diameter of the target surface.

[0012] In some embodiments, the far-infrared optical system satisfies: wherein, the is the maximum phase difference of the metalens at the working wavelength, the f m is the focal length of the metalens, the BFL is the back focal length of the far-infrared optical system, and the CT m is the central thickness of the metalens, and the FOV is the maximum field of view angle of the far-infrared optical system.

[0013] In some embodiments, the far-infrared optical system satisfies: wherein, the f is the effective focal length of the far-infrared optical system, and the EPD is the entrance pupil diameter of the far-infrared optical system.

[0014] In some embodiments, the far-infrared optical system further includes a diaphragm, and the diaphragm is disposed on the object side of the refractive lens; alternatively, the diaphragm is disposed between the refractive lens and the metalens.

[0015] A second aspect of the embodiments of the present application provides a far-infrared optical lens, which includes an imaging detector and the far-infrared optical system as described in any one of the above; the imaging detector is disposed on the image plane of the far-infrared optical system.

[0016] The far-infrared optical system provided by the present application sequentially includes, along the optical axis from the object side to the image side: a refractive lens and a metalens; the object side surface of the refractive lens bulges toward the image side, and the image side surface of the refractive lens bulges toward the image side; the optical power of the metalens is positive, and the metalens includes a substrate and a micro-nano structure, and the micro-nano structure is disposed on the object side surface and / or the image side surface of the substrate; wherein, the far-infrared optical system satisfies: 0.02 mm ≤ L ≤ 1 mm, where L is the distance between the image side surface of the metalens and the image plane of the far-infrared optical system. The overall optical length of the far-infrared optical system provided by the present application is relatively small. Therefore, the volume of the far-infrared optical system is small. The far-infrared optical system includes a refractive lens and a metalens. Since the metalens not only has the function of modulating light, but also can act as a protective glass, therefore, the far-infrared optical system provided by the present application does not need to be provided with a protective glass as an optical element, which can improve the integration of the far-infrared optical system, and further can further compress the volume and production cost of the far-infrared optical system. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] 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 obvious.

[0018] Figure 1 FIG. shows a schematic diagram of the architecture layout of the far-infrared optical system in an embodiment of the present application.

[0019] Figure 2 FIG. shows the field curvature diagram of the far-infrared optical system in an embodiment of the present application.

[0020] Figure 3 FIG. shows the distortion diagram of the far-infrared optical system in an embodiment of the present application.

[0021] Figure 4 FIG. shows the lateral chromatic aberration diagram of the far-infrared optical system in an embodiment of the present application.

[0022] Figure 5 FIG. shows a schematic diagram of the architecture layout of the far-infrared optical system in an embodiment of the present application.

[0023] Figure 6 FIG. shows the field curvature diagram of the far-infrared optical system in an embodiment of the present application.

[0024] Figure 7 FIG. shows the distortion diagram of the far-infrared optical system in an embodiment of the present application.

[0025] Figure 8Shows the vertical chromatic aberration diagram of the far-infrared optical system in an embodiment of the present application.

[0026] Figure 9 Shows the schematic diagram of the architecture layout of the far-infrared optical system in an embodiment of the present application.

[0027] Figure 10 Shows the field curvature diagram of the far-infrared optical system in an embodiment of the present application.

[0028] Figure 11 Shows the distortion diagram of the far-infrared optical system in an embodiment of the present application.

[0029] Figure 12 Shows the vertical chromatic aberration diagram of the far-infrared optical system in an embodiment of the present application.

[0030] Reference numerals

[0031] 100, far-infrared optical system;

[0032] 10, refractive lens;

[0033] 20, metalens; 210, substrate; 220, micro-nano structure;

[0034] 30, aperture;

[0035] A, object plane; B, image plane; S, optical axis. Detailed implementation manners

[0036] 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 this application will be more complete and comprehensive, and will fully convey the concept of the example embodiments to those skilled in the art. The drawings are merely 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.

[0037] In addition, the described features, structures, or characteristics can be combined in any suitable manner in one or more example embodiments. In the following description, numerous specific details are provided to give a thorough understanding of the example embodiments of the present application. However, those skilled in the art will realize that the technical solutions of the present application can be practiced without one or more of the specific details, or other modules, components, etc. can be adopted. In other cases, well-known structures, methods, implementations, or operations are not shown or described in detail to avoid obscuring the various aspects of the present application.

[0038] Please refer to Figure 1 , Figure 1FIG. 0 shows a schematic diagram of the architecture layout of a far-infrared optical system 100 according to an embodiment of the present application. Among them, the optical axis S is the center line of the light beam. In Figure 1 it, the object is located on the left side of the leftmost lens, that is, the object side is located on the left side of the leftmost lens, and the object surface A is located on the object side. The image formed by the far-infrared optical system 100 is located on the right side of the rightmost lens, that is, the image side is located on the right side of the rightmost lens, and the image surface B is located on the image side. Therefore, the direction from the object surface A to the image surface B along the optical axis S is the same as the direction from the object side to the image side along the optical axis S.

[0039] The side of each optical element of the far-infrared optical system 100 close to the object side is the object side of the corresponding optical element, and the side of each optical element of the far-infrared optical system 100 close to the image side is the image side of the corresponding optical element. For example, the side of the aperture 30 close to the object side is the object side of the aperture 30. The surface of each optical element of the far-infrared optical system 100 close to the object side is the object side surface of the corresponding optical element, and the surface of each optical element of the far-infrared optical system 100 close to the image side is the image side surface of the corresponding optical element. For example, the surface of the aperture 30 close to the image side is the image side surface of the aperture 30.

[0040] The far-infrared optical system 100 includes a refractive lens 10 and a meta-lens 20, and the refractive lens 10 and the meta-lens 20 are arranged in sequence along the direction from the object side to the image side of the optical axis S.

[0041] The focal length of the refractive lens 10 can be positive or negative. Specifically, in some embodiments, the optical power of the refractive lens 10 is positive, and in other embodiments, the optical power of the refractive lens 10 is negative. The object side surface of the refractive lens 10 bulges toward the image side, and the image side surface of the refractive lens 10 bulges toward the image side.

[0042] The optical power of the meta-lens 20 is positive. The meta-lens 20 includes a substrate 210 and a micro-nano structure 220, and the micro-nano structure 220 is arranged on the object side surface and / or the image side surface of the substrate 210. According to the adopted phase modulation method, the corresponding phase modulation formula can be adaptively used to configure the parameters of the micro-nano structure 220, so that the meta-lens 20 has the expected optical performance.

[0043] The far-infrared optical system 100 satisfies Condition 1: 0.02 mm ≤ L ≤ 1 mm, where L is the distance between the image side surface of the meta-lens 20 and the image surface B of the far-infrared optical system 100.

[0044] Conditional formula 1 reflects the distance between the metalens 20 and the image plane B of the far-infrared optical system 100. It can be seen from conditional formula 1 that the distance between the metalens 20 and the image plane B of the far-infrared optical system 100 is relatively close. An imaging detector adapted to the far-infrared optical system 100 is usually arranged at the image plane B of the far-infrared optical system 100. Therefore, the distance between the metalens 20 and the imaging detector is also relatively close. Thus, the metalens 20 can protect the imaging detector arranged at the image plane B. Therefore, the far-infrared optical system 100 provided in this application does not need to be provided with an optical element of a protective glass, which can improve the integration of the far-infrared optical system 100, and further can reduce the volume and production cost of the far-infrared optical system 100.

[0045] It is worth mentioning that, from another perspective, it can also be understood that: the substrate 210 of the metalens 20 is used as a protective glass, and the micro-nano structure 220 is processed on the substrate 210, so that the metalens 20 not only has the function of the metalens 20 itself, but also the metalens 20 plays the role of a protective glass. Since there is no need to additionally provide a protective glass, the usage amount of optical elements can also be reduced. The far-infrared optical system 100 also has the advantages of high integration and small volume, making the far-infrared optical system 100 have the advantages of miniaturization and light weight.

[0046] The optical total length of the far-infrared optical system 100 provided in this application is relatively small. Therefore, the volume of the far-infrared optical system 100 is relatively small. The far-infrared optical system 100 includes a refractive lens 10 and a metalens 20. Since the metalens 20 not only has the function of modulating light, but also the metalens 20 can play the role of a protective glass. Therefore, the far-infrared optical system 100 provided in this application does not need to be provided with an optical element of a protective glass, which can improve the integration of the far-infrared optical system 100, and further can further compress the volume and production cost of the far-infrared optical system 100.

[0047] Further, in some embodiments, the far-infrared optical system 100 satisfies conditional formula 2: 0.05 mm ≤ L ≤ 0.10 mm. Since the size of L affects the optical total length of the far-infrared optical system 100, the smaller L is, the smaller the volume of the far-infrared optical system 100 is; but when L is relatively small, the distance between the metalens 20 and the imaging detector is relatively close, and it is easy for the metalens 20 to collide with the imaging detector during assembly, making the assembly difficult. Therefore, when L = 0.05 mm, the optical total length of the far-infrared optical system 100 is relatively short, and the installation difficulty can be reduced.

[0048] Further, in some embodiments, L = 0.05 mm, so that the far-infrared optical system 100 takes into account the advantages of both a relatively short optical total length and a relatively low installation difficulty.

[0049] In some embodiments, the micro-nano structure 220 is arranged on the object side of the substrate 210.

[0050] In some embodiments, the micro-nano structure 220 is disposed on the image side of the substrate 210.

[0051] In some embodiments, the micro-nano structure 220 is disposed on both the object side and the image side of the substrate 210, so that the metalens 20 has a high degree of design freedom.

[0052] In some embodiments, the micro-nano structure 220 is a positive micro-nano structure.

[0053] In some embodiments, the micro-nano structure 220 is a negative micro-nano structure.

[0054] In some embodiments, the micro-nano structure 220 has one layer, so that the manufacturing process of the metalens 20 is compatible with the existing semiconductor manufacturing process, which is convenient for the manufacturing of the metalens 20.

[0055] In some embodiments, the micro-nano structure 220 has two or more layers, so that the metalens 20 has a large and expected optical power.

[0056] For the metalens 20, the position where the micro-nano structure 220 is disposed, the positive or negative of the micro-nano structure 220, and the number of layers of the micro-nano structure 220 can be freely combined as long as the metalens 20 has expected performance.

[0057] In some embodiments, the phase distribution of the metalens 20 satisfies the following formula:

[0058]

[0059]

[0060] where r is the distance between the center of the surface of the metalens 20 where the micro-nano structure 220 is disposed and any point on the surface of the metalens 20 where the micro-nano structure 220 is disposed, λ is the central wavelength of the working band of the metalens 20, is the phase constant, (x, y) is the two-dimensional coordinate of the surface of the metalens 20, a i 、b i 、a ij 、b ij are all real coefficients, N is the number of phase coefficient terms, f m is the focal length of the metalens 20.

[0061] In some embodiments, the refractive lens 10 is an aspherical lens, so that the far-infrared optical system 100 has excellent performance in aberration control, and the imaging quality of the far-infrared optical system 100 can be further improved.

[0062] In some embodiments, the refractive lens 10 is a spherical lens. Since spherical lenses have low cost and are easy to process, the production cost and processing difficulty of the far-infrared optical system 100 can be further reduced.

[0063] In some embodiments, the material of the refractive lens 10 is chalcogenide glass, which enables the refractive lens 10 to be either an aspherical lens or a spherical lens, increasing the design freedom of the refractive lens 10. Moreover, the refractive lens 10 made of chalcogenide glass has a high transmittance, which can improve the imaging quality of the far-infrared optical system 100.

[0064] In some embodiments, the material of the refractive lens 10 is silicon. Since the cost of silicon lenses is relatively low, when the material of the refractive lens 10 is silicon, the production cost of the far-infrared optical system 100 can be further reduced.

[0065] In some embodiments, the material of the refractive lens 10 is germanium. Since germanium has a relatively high refractive index, the thickness of the refractive lens 10 can be reduced, and thus the far-infrared optical system 100 can have the advantage of being lightweight.

[0066] In some embodiments, the far-infrared optical system 100 satisfies Conditional Equation Three: where TTL (Total Track Length, abbreviated as TTL) is the total optical length of the far-infrared optical system 100, f s is the focal length of the refractive lens 10, BFL (Back Focal Length, abbreviated as BFL) is the back focal length of the far-infrared optical system 100. In this application, BFL is equal to the distance between the image side of the last lens (the meta-lens 20) and the image plane B on the optical axis. f is the effective focal length of the far-infrared optical system 100. TTL, f s , BFL, and f have the same dimension, which is a length unit, such as millimeters.

[0067] The upper and lower limits of Conditional Equation Three represent the influence degree of different back focal lengths on the total optical length. It can be seen from Conditional Equation Three that the shorter the back focal length, the larger the value of Conditional Equation Three. Through Conditional Equation Three, the far-infrared optical system 100 can have an appropriate back focal length, which is convenient for the assembly of the far-infrared optical system 100.

[0068] In some embodiments, the far-infrared optical system 100 satisfies Conditional Equation Four: ImgH is the radius of the imaging area corresponding to the maximum half field of view angle on the image plane B of the far-infrared optical system 100. Here, "corresponding to the maximum half field of view angle" means the angular range from the central field of view to the maximum half field of view angle, rather than a specific angle of the maximum half field of view angle. FOV (Field of View, abbreviated as FOV) is the maximum field of view angle of the far-infrared optical system 100, and the unit of FOV is degree. f is the effective focal length of the far-infrared optical system 100, and TTL is the total optical length of the far-infrared optical system 100. ImgH, f, and TTL have the same dimension, which is a length unit, such as millimeter.

[0069] Conditional formula four reflects that the maximum image height that the far-infrared optical system 100 can achieve is related to the effective focal length and the total optical length of the far-infrared optical system 100. From conditional formula four, it can be seen that as the effective focal length and the total length of the far-infrared optical system 100 decrease, the image height of the far-infrared optical system 100 will increase. Through conditional formula four, the far-infrared optical system 100 can have an appropriate image height.

[0070] In some embodiments, the far-infrared optical system 100 satisfies conditional formula five: where, BFL is the back focal length of the far-infrared optical system 100, CT m is the central thickness of the superlens 20, that is, CT m is the thickness of the superlens 20 on the optical axis S. L sm is the distance between the image side of the refractive lens 10 and the object side of the superlens 20 on the optical axis S, f is the effective focal length of the far-infrared optical system 100, f m is the focal length of the superlens 20. BFL, CT m , L sm , f, f m have the same dimension, which is a length unit, such as millimeter.

[0071] The lower limit of conditional formula five reflects the maximum optical power that the superlens 20 can achieve when the back focal length of the far-infrared optical system 100 decreases, and the upper limit of conditional formula five reflects the minimum optical power that the superlens 20 can achieve when the back focal length of the far-infrared optical system 100 increases. Conditional formula five can ensure that the superlens 20 has an appropriate optical power, so that the superlens 20 can compensate for the chromatic aberration of the far-infrared optical system 100, and at the same time can avoid introducing a large amount of chromatic aberration by the superlens 20.

[0072] In some embodiments, the far-infrared optical system 100 satisfies conditional formula six: where, R 1 is the radius of curvature of the object side of the refractive lens 10, R 2 is the radius of curvature of the image side of the refractive lens 10. r 1 is half of the effective diameter of the object side of the refractive lens 10, r2 is half of the effective diameter of the image side of the refractive lens 10. In this application, the "effective diameter" of the lens refers to the diameter of the largest light-transmitting area of the lens. CT m is the central thickness of the metalens 20. The surface of the substrate 210 provided with the micro-nano structure 220 is the target surface, r m is half of the effective diameter of the target surface. If the object side and the image side of the substrate 210 are both provided with the micro-nano structure 220, at this time, both the object side and the image side of the substrate 210 are the target surfaces, and at this time r m is equal to the average value of half of the effective diameter of the object side of the substrate 210 and half of the effective diameter of the image side of the substrate 210. R 1 、R 2 、r 1 、r 2 、r m 、CT m have the same dimension, which is a length unit, such as millimeter.

[0073] Conditional formula six indicates that the radius of curvature and the effective diameter of the refractive lens 10 will affect the effective diameter of the metalens 20. Through conditional formula six, the effective diameter of the metalens 20 can be controlled within a reasonable range, and then the diameter of the metalens 20 can be indirectly controlled within a reasonable range, which is beneficial to the processing of the metalens 20.

[0074] In some embodiments, the far-infrared optical system 100 satisfies conditional formula seven: Among them, is the maximum phase difference of the metalens 20 at the working wavelength, The unit of is rad. f m is the focal length of the metalens 20, BFL is the optical back focal length of the far-infrared optical system 100, CT m is the central thickness of the metalens 20. FOV is the maximum field of view angle of the far-infrared optical system 100, and the unit of FOV is degree. f m 、BFL、CT m have the same dimension, which is a length unit, such as millimeter.

[0075] Conditional formula seven reflects the relationship between the optical back focal length of the far-infrared optical system 100 and the maximum phase difference of the metalens 20. The lower limit of conditional formula seven represents the maximum value of the maximum phase difference of the metalens 20 corresponding to the shortening of the optical back focal length, and the upper limit of conditional formula seven represents the minimum value of the maximum phase difference of the metalens 20 corresponding to the increase of the optical back focal length.

[0076] In some embodiments, the far-infrared optical system 100 satisfies conditional formula eight: Among them, f is the effective focal length of the far-infrared optical system 100, and EPD (Entrance Pupil Diameter, abbreviated as EPD) is the entrance pupil diameter of the far-infrared optical system 100. f and EPD have the same dimension, both are length units, such as millimeters.

[0077] Conditional formula eight reflects the range of the F-number of the far-infrared optical system 100. It can be seen from conditional formula eight that the F-number of the far-infrared optical system 100 is relatively small, which can greatly improve the light input of the far-infrared optical system 100, and when the imaging detector has a low response to light energy, collect as much energy entering the far-infrared optical system 100 as possible, thereby ensuring excellent imaging quality.

[0078] In some embodiments, the maximum field of view angle of the far-infrared optical system 100 can reach 160°, so that the far-infrared optical system 100 can meet the requirements of large field of view imaging.

[0079] In some embodiments, the far-infrared optical system 100 further includes a diaphragm 30, and the diaphragm 30 is used to control the light input of the far-infrared optical system 100 to ensure that the far-infrared optical system 100 can work effectively and generate high-quality images.

[0080] Furthermore, in some embodiments, the diaphragm 30 is disposed on the object side of the refractive lens 10. Specifically, the setting position of the diaphragm 30 satisfies any one of the following conditions:

[0081] (1) The diaphragm 30 is located on the object side of the refractive lens 10, and the diaphragm 30 is spaced from the refractive lens 10.

[0082] (2) The diaphragm 30 is located on the object side of the refractive lens 10, and the diaphragm 30 is disposed in contact with the object side surface of the refractive lens 10.

[0083] Furthermore, in some embodiments, the diaphragm 30 is disposed between any two adjacent lenses. Specifically, the setting position of the diaphragm 30 satisfies any one of the following conditions:

[0084] (1) The diaphragm 30 is located between the refractive lens 10 and the meta-lens 20, and the diaphragm 30 is disposed in contact with the image side surface of the refractive lens 10.

[0085] (2) The diaphragm 30 is located between the refractive lens 10 and the meta-lens 20, and the diaphragm 30 is spaced from both the refractive lens 10 and the meta-lens 20.

[0086] (3) The diaphragm 30 is located between the refractive lens 10 and the meta-lens 20, and the diaphragm 30 is disposed in contact with the object side surface of the meta-lens 20.

[0087] The far-infrared optical system 100 provided by this application has the following advantages:

[0088] (1) There is no need to use a protective glass. Saving this optical component of the protective glass can reduce the production cost of the far-infrared optical system 100, and moreover, it can also improve the integration of the far-infrared optical system 100;

[0089] (2) F-number ≤ 1.05, which can ensure that the lens has a high light intensity response rate;

[0090] (3) TTL ≤ 2.1 mm, with a relatively short overall optical length;

[0091] (4) The maximum field of view angle can reach 160°, which can meet large-field imaging.

[0092] Embodiment 1

[0093] Figure 1 Shows a schematic diagram of the architectural layout of the far-infrared optical system 100 provided by Embodiment 1. Figure 1 The mid- and far-infrared optical system 100 sequentially includes, along the optical axis S from the object surface A to the image surface B: a diaphragm 30, a refractive lens 10, and a metalens 20. Among them, the refractive lens 10 is a spherical lens, and the micro-nano structure 220 is located on the image side surface of the metalens 20. Some parameters of the far-infrared optical system 100 provided by Embodiment 1 are shown in Table 1-1.

[0094] Table 1-1. Some parameters of the far-infrared optical system 100 provided by Embodiment 1

[0095] Parameter Data Optical Total Length (TTL) 2.0766 mm Maximum Field of View (2ω) 160° F - number 0.99 Effective Focal Length 0.857 mm Operating Wavelength Band Far - Infrared (8μm - 12μm)

[0096] As can be seen from Table 1-1, the working band of the far-infrared optical system 100 is 8 μm - 12 μm, the maximum field of view angle of the far-infrared optical system 100 is 160°, and the field of view of the far-infrared optical system 100 is relatively large. The overall optical length of the far-infrared optical system 100 is relatively short, only 2.0766 mm. Therefore, the volume of the far-infrared optical system 100 provided by Embodiment 1 is relatively small. The F-number of the far-infrared optical system 100 is 0.99, which can greatly increase the light input amount of the far-infrared optical system 100, and can collect as much energy as possible entering the far-infrared optical system 100 under the condition that the imaging detector has a low response to light energy, thereby ensuring excellent imaging quality.

[0097] Along the direction of the optical axis S from the object surface A to the image surface B, starting from the diaphragm 30, each surface in the far-infrared optical system 100 is numbered, and after summarizing the parameters of each surface, the following Table 1-2 is obtained.

[0098] Table 1-2. Parameters of each surface in the far-infrared optical system 100 provided by Embodiment 1

[0099] Surface Number Surface Type Radius of Curvature (mm) Thickness (mm) Material 1 Aperture Infinity 5.36E-02 - 2 Spherical Surface -6.28E+00 9.96E-01 Silicon 3 Spherical Surface -1.46E+00 4.77E-01 - 4 Spherical Surface Infinity 5.00E-01 Silicon 5 Structural Surface Infinity 5.00E-02 - 6 Image Plane Infinity - -

[0100] For each surface in Table 1-2, surface 1 is the aperture stop 30. Surface 2 is the object side surface of the refractive lens 10, and surface 3 is the image side surface of the refractive lens 10. Surface 4 is the object side surface of the metalens 20, and surface 5 is the image side surface of the metalens 20. Surface 6 is the image plane B.

[0101] 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 5.36E-02 mm, and the material between surface 1 and surface 2 is air. Surface 2 is a spherical surface, the radius of curvature of surface 2 is -6.28E+00 mm, the distance between surface 2 and surface 3 is 9.96E-01 mm, and the material between surface 2 and surface 3 is silicon. Surface 3 is a spherical surface, the radius of curvature of surface 3 is -1.46E+00 mm, the distance between surface 3 and surface 4 is 4.77E-01 mm, and 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 5.00E-01 mm, and the material between surface 4 and surface 5 is silicon. 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 5.00E-02 mm, and the material between surface 5 and surface 6 is air.

[0102] Please refer to Figure 2 , Figure 2 which shows the field curvature diagram of the far-infrared optical system 100 provided in Embodiment 1. Figure 2 In the figure, the horizontal axis is the field curvature, and its unit is mm; Figure 2 the vertical axis in the figure is the Y-axis field of view, and its unit is degree. Among them, Figure 2 the field curvatures of far-infrared light with wavelengths of 8 μm, 9 μm, 10 μm, 11 μm, and 12 μm in the sagittal and meridional directions are shown. Since the field curvature curves of far-infrared light with wavelengths of 8 μm, 9 μm, 10 μm, 11 μm, and 12 μm in the sagittal direction almost completely overlap, therefore, in this embodiment, they are not distinguished and are uniformly marked as S; since the field curvature curves of far-infrared light with wavelengths of 8 μm, 9 μm, 10 μm, 11 μm, and 12 μm in the meridional direction almost completely overlap, therefore, in this embodiment, they are not distinguished and are uniformly marked as T. From Figure 2 it can be known that the maximum field curvature of the far-infrared optical system 100 provided in Embodiment 1 in the sagittal direction under far-infrared light with a wavelength of 10 μm is 0.123 mm, and the maximum field curvature of the far-infrared optical system 100 provided in Embodiment 1 in the meridional direction under far-infrared light with a wavelength of 10 μm is 0.157 mm. The field curvature is small, meeting the requirements for field curvature in the excellent imaging quality standard.

[0103] Please refer to Figure 3 , Figure 3The distortion diagram of the far-infrared optical system 100 provided in Embodiment 1 is shown, Figure 3 where the horizontal axis in Figure 3 is distortion, and its unit is percentage; Figure 3 where the vertical axis in Figure 3 is the Y-axis field of view, and its unit is degree.

[0104] Please refer to Figure 4 , Figure 4 which shows the vertical chromatic aberration diagram of the far-infrared optical system 100 provided in Embodiment 1 under far-infrared light with wavelengths of 8 μm, 9 μm, 10 μm, 11 μm, and 12 μm. Figure 4 The abscissa of Figure 4 is the position of light rays with different wavelengths on the vertical image plane B, and the unit is micrometer. Figure 4 The ordinate of Figure 4 is the field angle, and its unit is degree.

[0105] Embodiment 2

[0106] Figure 5 The schematic diagram of the architecture layout of the far-infrared optical system 100 provided in Embodiment 2 is shown. Figure 5 In

[0107] the far-infrared optical system 100 along the optical axis S from the object plane A to the image plane B sequentially includes: a diaphragm 30, a refractive lens 10, and a metalens 20. Among them, the refractive lens 10 is a spherical lens, and the micro-nano structure 220 is located on the image side of the metalens 20. Some parameters of the far-infrared optical system 100 provided in Embodiment 2 are shown in Table 2-1.

[0108] Parameter Data Optical Total Length (TTL) 1.892 mm Maximum Field of View (2ω) 160° F - number 1.05 Effective Focal Length 0.66 mm Operating Wavelength Band Far - Infrared (8μm - 12μm)

[0109] As can be seen from Table 2-1, the working wavelength band of the far-infrared optical system 100 is 8μm - 12μm, the maximum field of view angle of the far-infrared optical system 100 is 160°, and the field of view of the far-infrared optical system 100 is relatively large. The total optical length of the far-infrared optical system 100 is relatively short, only 1.892 mm. Therefore, the volume of the far-infrared optical system 100 provided in Embodiment 2 is relatively small. The F number of the far-infrared optical system 100 is 1.05, which can greatly increase the amount of incident light of the far-infrared optical system 100, and collect as much energy as possible entering the far-infrared optical system 100 when the imaging detector has a low response to light energy, thereby ensuring excellent imaging quality.

[0110] Along the optical axis S from the object plane A to the image plane B, starting from the aperture 30, each surface in the far-infrared optical system 100 is numbered, and after summarizing the parameters of each surface, the following Table 2-2 is obtained.

[0111] Table 2-2. Parameters of each surface in the far-infrared optical system 100 provided in Embodiment 2

[0112] Surface Number Surface Type Radius of Curvature (mm) Thickness (mm) Material 1 Aperture Infinity 6.23E-02 - 2 Spherical Surface -8.00E+00 9.92E-01 Silicon 3 Spherical Surface -1.53E+00 3.77E-02 - 4 Spherical Surface Infinity 3.00E-01 Silicon 5 Structural Surface Infinity 5.00E-01 - 6 Image Plane Infinity - -

[0113] For the analysis of each surface in Table 2-2, reference can be made to Embodiment 1, and this embodiment will not analyze it again.

[0114] Please refer to Figure 6 , Figure 6 , which shows the field curvature diagram of the far-infrared optical system 100 provided in Embodiment 2. Figure 6 In Figure 6 , the horizontal axis is the field curvature, and its unit is mm; Figure 6 In Figure 6 , the vertical axis is the Y-axis field of view, and its unit is degree. Among them,

[0115] Please refer to Figure 7 ,Figure 7 The distortion diagram of the far-infrared optical system 100 provided in Embodiment 2 is shown, Figure 7 where the horizontal axis in it is distortion, and its unit is percentage; Figure 7 the vertical axis in it is the Y-axis field of view, and its unit is degree. Figure 7 The distortion curves of the far-infrared optical system 100 provided in Embodiment 2 under far-infrared light with wavelengths of 8 μm, 9 μm, 10 μm, 11 μm, and 12 μm are respectively shown. Since the five curves almost completely overlap, they are not distinguished in this embodiment. From Figure 7 it can be seen that the maximum distortion of the far-infrared optical system 100 provided in Embodiment 2 is -80%.

[0116] Please refer to Figure 8 , Figure 8 which shows the lateral chromatic aberration diagram of the far-infrared optical system 100 provided in Embodiment 2 under far-infrared light with wavelengths of 8 μm, 9 μm, 10 μm, 11 μm, and 12 μm, Figure 8 the abscissa of which is the position of light rays with different wavelengths on the lateral image plane B, and the unit is micrometer, Figure 8 and the ordinate of which is the field angle, and its unit is degree. Figure 8 A total of five curves are shown in it. Among them, the M1 curve is the far-infrared light with a wavelength of 8 μm, the M2 curve is the far-infrared light with a wavelength of 9 μm, the M3 curve is the far-infrared light with a wavelength of 10 μm, the M4 curve is the far-infrared light with a wavelength of 11 μm, and the M5 curve is the far-infrared light with a wavelength of 12 μm. Among them, the abscissa of the far-infrared light curve M3 with a wavelength of 10 μm is 0 μm. From Figure 8 it can be seen that within the full field of view, the maximum lateral chromatic aberration is about 4.2 μm, the chromatic aberration is small, the dispersion is not obvious, and it meets the requirements for chromatic aberration in the excellent imaging quality standard.

[0117] Embodiment 3

[0118] Figure 9 The schematic diagram of the architecture layout of the far-infrared optical system 100 provided in Embodiment 3 is shown, Figure 9 in which the far-infrared optical system 100 along the optical axis S from the object plane A to the image plane B successively includes: a diaphragm 30, a refractive lens 10, and a meta-lens 20. Among them, the refractive lens 10 is a spherical lens, and the micro-nano structure 220 is located on the image side of the meta-lens 20. Some parameters of the far-infrared optical system 100 provided in Embodiment 3 are shown in Table 3-1.

[0119] Table 3-1. Some parameters of the far-infrared optical system 100 provided in Embodiment 3

[0120] Parameter Data Optical Total Length (TTL) 2.0177 mm Maximum Field of View (2ω) 160° F - number 1.01 Effective Focal Length 0.59 mm Operating Wavelength Band Far - Infrared (8μm - 12μm)

[0121] As can be seen from Table 3-1, the working wavelength band of the far-infrared optical system 100 is 8 μm - 12 μm, the maximum field of view angle of the far-infrared optical system 100 is 160°, and the field of view of the far-infrared optical system 100 is relatively large. The total optical length of the far-infrared optical system 100 is relatively short, only 2.0177 mm. Therefore, the volume of the far-infrared optical system 100 provided in Embodiment 3 is relatively small. The F number of the far-infrared optical system 100 is 1.01, which can greatly increase the amount of incident light of the far-infrared optical system 100, and can collect as much energy entering the far-infrared optical system 100 as possible when the imaging detector has a low response to light energy, thereby ensuring excellent imaging quality.

[0122] Along the optical axis S from the object plane A to the image plane B, starting from the aperture 30, each surface in the far-infrared optical system 100 is numbered, and after summarizing the parameters of each surface, the following Table 3-2 is obtained.

[0123] Table 3-2. Parameters of each surface in the far-infrared optical system 100 provided in Embodiment 3

[0124] Surface Number Surface Type Radius of Curvature (mm) Thickness (mm) Material 1 Aperture Infinity 5.17E-02 - 2 Spherical Surface -8.45E+00 9.82E-01 Silicon 3 Spherical Surface -1.53E+00 2.84E-01 - 4 Spherical Surface Infinity 5.00E-01 Silicon 5 Structural Surface Infinity 2.00E-01 - 6 Image Plane Infinity - -

[0125] For the analysis of each surface in Table 3-2, reference can be made to Embodiment 1, and this embodiment will not analyze it again.

[0126] Please refer to Figure 10 , Figure 10 which shows the field curvature diagram of the far-infrared optical system 100 provided in Embodiment 3. Figure 10 In the horizontal axis is the field curvature, and its unit is mm; Figure 10 in the vertical axis is the Y-axis field of view, and its unit is degree. Among them, Figure 10 shows the field curvature of far-infrared light with wavelengths of 8 μm, 9 μm, 10 μm, 11 μm, and 12 μm in the sagittal and meridional directions. Since the field curvature curves of far-infrared light with wavelengths of 8 μm, 9 μm, 10 μm, 11 μm, and 12 μm in the sagittal direction almost completely overlap, therefore, this embodiment does not distinguish them and uniformly marks them as S; since the field curvature curves of far-infrared light with wavelengths of 8 μm, 9 μm, 10 μm, 11 μm, and 12 μm in the meridional direction almost completely overlap, therefore, this embodiment does not distinguish them and uniformly marks them as T. As can be seen from Figure 10 , the maximum field curvature of the far-infrared optical system 100 provided in Embodiment 3 in the sagittal direction under far-infrared light with a wavelength of 10 μm is 0.061 mm, and the maximum field curvature of the far-infrared optical system 100 provided in Embodiment 3 in the meridional direction under far-infrared light with a wavelength of 10 μm is 0.152 mm. The field curvature is small, meeting the requirements for field curvature in the excellent imaging quality standard.

[0127] Please refer to Figure 11 ,Figure 11 Shows the distortion diagram of the far-infrared optical system 100 provided in Embodiment 3, Figure 11 where the horizontal axis in it is distortion, and its unit is percentage; Figure 11 the vertical axis in it is the Y-axis field of view, and its unit is degree. Figure 11 shows the distortion curves of the far-infrared optical system 100 provided in Embodiment 3 under far-infrared light with wavelengths of 8 μm, 9 μm, 10 μm, 11 μm, and 12 μm. Since the five curves almost completely overlap, they are not distinguished in this embodiment. From Figure 11 it can be known that the maximum distortion of the far-infrared optical system 100 provided in Embodiment 3 is -79.6%.

[0128] Please refer to Figure 12 , Figure 12 shows the lateral chromatic aberration diagram of the far-infrared optical system 100 provided in Embodiment 3 under far-infrared light with wavelengths of 8 μm, 9 μm, 10 μm, 11 μm, and 12 μm, Figure 12 the abscissa of which is the position of light rays with different wavelengths on the lateral image plane B, and the unit is micrometer, Figure 12 the ordinate of which is the field angle, and its unit is degree. Figure 12 A total of 5 curves are shown in it. Among them, the M1 curve is far-infrared light with a wavelength of 8 μm, the M2 curve is far-infrared light with a wavelength of 9 μm, the M3 curve is far-infrared light with a wavelength of 10 μm, the M4 curve is far-infrared light with a wavelength of 11 μm, and the M5 curve is far-infrared light with a wavelength of 12 μm. Among them, the abscissa of the far-infrared light curve M3 with a wavelength of 10 μm is 0 μm. From Figure 12 it can be known that within the full field of view range, the maximum lateral chromatic aberration is about 3.9 micrometers, the chromatic aberration is small, the dispersion is not obvious, and it meets the requirements for chromatic aberration in the excellent imaging quality standard.

[0129] After summarizing the various parameters of the far-infrared optical system 100 provided in the above 3 embodiments, Table 4 as shown below is obtained. The display of Table 4 is mainly used to illustrate that the various conditions met by the far-infrared optical system 100 provided in this application are all experimentally verified and supported.

[0130] Table 4. Various parameters of the far-infrared optical system 100 provided in each embodiment

[0131]

[0132]

[0133] The present application also provides a far-infrared optical lens (not shown in the figure), the far-infrared optical lens includes an imaging detector (not shown in the figure) and the above-mentioned far-infrared optical system 100. For the specific architecture of the far-infrared optical system 100, reference can be made to the above text and will not be elaborated here. The imaging detector is disposed on the image plane B of the far-infrared optical system 100. The imaging detector 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).

[0134] Those skilled in the art will readily conceive of other embodiments of the present application after considering the specification and practicing the utility model disclosed herein. The present application is intended to cover any variations, uses, or adaptations of the present application, which follow the general principles of the present application and include known common knowledge or conventional technical means in the technical field not disclosed in the present application. The specification and examples are only regarded as exemplary, and the true scope and spirit of the present application are pointed out by the appended claims.

Claims

1. A far-infrared optical system, characterized in that: The far-infrared optical system comprises, in order from the object side to the image side along the optical axis: a refractive lens and a super lens; the object side surface of the refractive lens is convex to the image side, and the image side surface of the refractive lens is convex to the image side; the optical power of the super lens is positive, the super lens comprises a substrate and a micro-nano structure, and the micro-nano structure is arranged on the object side surface and / or the image side surface of the substrate; The far-infrared optical system satisfies: 0.02 mm ≤ L ≤ 1 mm, wherein L is the distance between the image side surface of the super lens and the image plane of the far-infrared optical system.

2. The far-infrared optical system according to claim 1, characterized in that: The refractive lens is a spherical lens.

3. The far-infrared optical system according to claim 1 or 2, characterized in that: The far-infrared optical system meets the following requirements: Wherein, the TTL is the total optical length of the far-infrared optical system, and the f s is the focal length of the refractive lens, the BFL is the optical back focal length of the far-infrared optical system, and f is the effective focal length of the far-infrared optical system.

4. The far-infrared optical system according to claim 1 or 2, characterized in that: The far-infrared optical system meets the following requirements: The ImgH is the imaging area radius of the far-infrared optical system on the image plane corresponding to the maximum half field of view angle, the FOV is the maximum field of view angle of the far-infrared optical system, f is the effective focal length of the far-infrared optical system, and the TTL is the total optical length of the far-infrared optical system.

5. The far-infrared optical system according to claim 1 or 2, characterized in that: The far-infrared optical system meets the following requirements: Wherein, the BFL is the optical back focal length of the far-infrared optical system, and the CT m is the center thickness of the superlens, the L sm is the distance between the image side of the refractive lens and the object side of the super lens on the optical axis, f is the effective focal length of the far-infrared optical system, and f m is the focal length of the metalens.

6. The far-infrared optical system according to claim 1 or 2, characterized in that: The far-infrared optical system meets the following requirements: Wherein, R1 is the curvature radius of the object side surface of the refractive lens, R2 is the curvature radius of the image side surface of the refractive lens, r1 is half of the effective diameter of the object side surface of the refractive lens, r2 is half of the effective diameter of the image side surface of the refractive lens, and CT m is the center thickness of the superlens; the surface of the substrate provided with the micro-nano structure is the target surface, and the r m is half of the effective diameter of the target surface.

7. The far-infrared optical system according to claim 1 or 2, characterized in that: The far-infrared optical system meets the following requirements: Among them, the is the maximum phase difference of the metalens at the working wavelength, and the f m is the focal length of the metalens, the BFL is the optical back focal length of the far-infrared optical system, and the CT m is the central thickness of the metalens, and the FOV is the maximum field of view of the far-infrared optical system.

8. The far-infrared optical system according to claim 1 or 2, characterized in that: The far-infrared optical system meets the following requirements: Wherein, f is the effective focal length of the far-infrared optical system, and EPD is the entrance pupil diameter of the far-infrared optical system.

9. The far-infrared optical system according to claim 1 or 2, characterized in that: The far-infrared optical system further includes an aperture, which is disposed on the object side of the refractive lens; or, the aperture is disposed between the refractive lens and the super lens.

10. A far-infrared optical lens, characterized in that: The far-infrared optical lens comprises: an imaging detector and a far-infrared optical system as described in any one of claims 1 to 9; the imaging detector is arranged on the image plane of the far-infrared optical system.

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