Far infrared optical system and far infrared optical lens
By combining the first aspherical lens, the ultra-lens and the second aspherical lens, the ultra-lens are produced using micro-nano structure and semiconductor technology, the problems of imaging quality, cost and volume of the far-infrared optical system are solved, and efficient Imaging and cost reduction.
Patent Information
- Application Number
- CN202421215459.9
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-05-30
- Publication Date
- 2025-01-07
- Estimated Expiration
- 2034-05-30
AI Technical Summary
Existing far-infrared optical systems cannot take into account both better imaging quality, lower production costs and smaller volumes.
Using an optical system consisting of a first aspherical lens, an ultralens and a second aspherical lens, the ultralens includes a substrate and a micro-nano structure, with the opposite optical power, so that the far-infrared optical system has a higher imaging quality through combination, and Use semiconductor processes to produce ultralens to reduce costs.
On the premise of ensuring imaging quality, the system volume and production cost are compressed, achieving lower production costs and smaller volumes.
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Figure CN222319207U_ABST
Abstract
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] In the prior art, optical systems with better imaging quality have appeared in the far-infrared field, but most of them are realized by using germanium materials and setting multiple aspheric surfaces. The high price of germanium materials and the difficulty in processing aspheric lenses result in high production costs of the optical systems. In addition, the volume of the optical systems is still relatively large. The above shortcomings mean that there is still room for improvement. Utility Model Content
[0003] In response to the above technical problems, the embodiments of the present application provide a far-infrared optical system and a far-infrared optical lens, which aim to solve the problem that the far-infrared optical system in the prior art cannot simultaneously take into account better imaging quality, lower production cost and smaller size.
[0004] According to one aspect of an embodiment of the present application, a far-infrared optical system is disclosed, wherein the far-infrared optical system includes, in order from the object side to the image side along the optical axis: a first aspheric lens, a super lens, and a second aspheric lens, wherein the first aspheric lens is a negative lens, and the surface of the first aspheric lens close to the object side and the surface of the first aspheric lens close to the image side are both convex toward the object side; the second aspheric lens is a positive lens, and the surface of the second aspheric lens close to the object side and the surface of the second aspheric lens close to the image side are both convex toward the image side;
[0005] The superlens comprises a substrate and a micro-nano structure, wherein the micro-nano structure is respectively arranged on the surface of the substrate facing the object side and the surface of the substrate facing the image side; the surface of the superlens close to the object side is the front surface, and the surface of the superlens close to the image side is the rear surface, the optical focal length of the front surface of the superlens is opposite to the optical focal length of the rear surface of the superlens, and the optical focal length of the superlens is positive.
[0006] In some embodiments, the far-infrared optical system satisfies: Among them, f is the effective focal length of the far-infrared optical system, FOV is the maximum field of view angle of the far-infrared optical system, D is the entrance pupil diameter of the far-infrared optical system, and TTL is the total optical length of the far-infrared optical system.
[0007] In some embodiments, the far-infrared optical system satisfies: Wherein, the BFL is the optical back focal length of the far-infrared optical system, and the F Wis the working F number of the far-infrared optical system, D is the entrance pupil diameter of the far-infrared optical system, and TTL is the total optical length of the far-infrared optical system.
[0008] In some embodiments, the far-infrared optical system satisfies: Among them, the d 1 is the effective aperture of the first aspheric lens, and the f g1 is the paraxial focal length of the first aspheric lens, and the d 2 is the effective aperture of the second aspheric lens, and the f g2 is the paraxial focal length of the second aspheric lens.
[0009] In some embodiments, the far-infrared optical system satisfies: Among them, the is the phase distribution of any one of the front surface of the super lens and the rear surface of the super lens, is the phase distribution of the other of the front surface of the superlens and the rear surface of the superlens, and r is the distance between any point in the effective area of the superlens and the center of the superlens.
[0010] In some embodiments, the far-infrared optical system satisfies: Wherein, f is the effective focal length of the far-infrared optical system, and f m is the focal length of the metalens.
[0011] In some embodiments, the far-infrared optical system satisfies: Among them, the d 2 is the effective aperture of the second aspheric lens, the CT 2 is the center thickness of the second aspheric lens, the F W is the working F number of the far-infrared optical system, D is the entrance pupil diameter of the far-infrared optical system, and FOV is the maximum field of view angle of the far-infrared optical system.
[0012] In some embodiments, the far-infrared optical system satisfies: Among them, the n F is the refractive index of the first aspherical lens, the EPD is the exit pupil diameter of the far-infrared optical system, the FOV is the maximum field angle of the far-infrared optical system, and the R F1 is the radius of curvature of the surface of the first aspheric lens close to the object side.
[0013] In some embodiments, the far-infrared optical system satisfies: Among them, the R L1is the radius of curvature of the surface of the second aspheric lens close to the object side, and the R L2 is the radius of curvature of the surface of the second aspheric lens close to the image side, and the K L1 is the conic coefficient of the surface of the second aspheric lens close to the object side, and the K L2 is the conic coefficient of the surface of the second aspheric lens close to the image side.
[0014] In some embodiments, the far-infrared optical system satisfies: Wherein, the TTL is the total optical length of the far-infrared optical system, and the d 2 is the effective aperture of the second aspheric lens, the CT 1 is the center thickness of the first aspheric lens, the CT 2 is the center thickness of the second aspheric lens.
[0015] In some embodiments, the far-infrared optical system satisfies: Wherein, the TTL is the total optical length of the far-infrared optical system, and the f m is the focal length of the metalens, the F W is the working F number of the far-infrared optical system, and D is the entrance pupil diameter of the far-infrared optical system.
[0016] In some embodiments, the far-infrared optical system further includes an aperture stop, and the aperture stop is disposed on a side of the first aspherical lens close to the object side;
[0017] or,
[0018] The aperture is disposed between the first aspheric lens and the super lens;
[0019] or,
[0020] The aperture is disposed between the super lens and the second aspherical lens.
[0021] A second aspect of an embodiment of the present application provides a far-infrared optical lens, comprising: an imaging detector and any of the far-infrared optical systems described above; the imaging detector is arranged on the image plane of the far-infrared optical system.
[0022] The far-infrared optical system provided by the present application includes, from the object side to the image side along the optical axis, a first aspheric lens, a super lens, and a second aspheric lens in sequence. The first aspheric lens is a negative lens, and the surface of the first aspheric lens close to the object side and the surface of the first aspheric lens close to the image side are both convex to the object side; the second aspheric lens is a positive lens, and the surface of the second aspheric lens close to the object side and the surface of the second aspheric lens close to the image side are both convex to the image side. Among them, the super lens includes a substrate and a micro-nano structure, and the micro-nano structure is respectively arranged on the surface of the substrate facing the object side and the surface of the substrate facing the image side; the surface of the super lens close to the object side is the front surface, and the surface of the super lens close to the image side is the back surface, and the optical focal length of the front surface of the super lens is opposite to the optical focal length of the back surface of the super lens, and the optical focal length of the super lens is positive. In the present application, the optical power of the front surface of the metalens and the optical power of the rear surface of the metalens are opposite in positive and negative, the front surface of the metalens and the rear surface of the metalens are complementary, the metalens can eliminate certain chromatic aberrations of itself, and the optical power of the first aspheric lens and the second aspheric lens are opposite. Through the combination of the first aspheric lens, the metalens and the second aspheric lens, the far-infrared optical system has a higher imaging quality. The far-infrared optical system has a small number of lenses, which is conducive to controlling the cost of lens materials. In addition, the metalens can be produced using semiconductor technology. When mass-produced, the cost of a single metalens is low, which can further reduce the production cost of the far-infrared optical system. At the same time, the total optical length of the far-infrared optical system is relatively small. That is, the far-infrared optical system provided by the present application compresses the system volume and production cost to a certain extent while ensuring the imaging quality. BRIEF DESCRIPTION OF THE DRAWINGS
[0023] The above and other objects, features and advantages of the present application will become more apparent by describing in detail exemplary embodiments thereof with reference to the attached drawings.
[0024] Figure 1 A schematic diagram of the architecture layout of a far-infrared optical system in an embodiment of the present application is shown.
[0025] Figure 2 The MTF field of view curve of the far-infrared optical system in one embodiment of the present application is shown.
[0026] Figure 3 A field curvature diagram of a far-infrared optical system in an embodiment of the present application is shown.
[0027] Figure 4 A distortion diagram of a far-infrared optical system in an embodiment of the present application is shown.
[0028] Figure 5 A schematic diagram of the architecture layout of a far-infrared optical system in an embodiment of the present application is shown.
[0029] Figure 6The MTF field of view curve of the far-infrared optical system in one embodiment of the present application is shown.
[0030] Figure 7 A field curvature diagram of a far-infrared optical system in an embodiment of the present application is shown.
[0031] Figure 8 A distortion diagram of a far-infrared optical system in an embodiment of the present application is shown.
[0032] Fig. 9 A schematic diagram of the architecture layout of a far-infrared optical system in an embodiment of the present application is shown.
[0033] Fig.10 The MTF field of view curve of the far-infrared optical system in one embodiment of the present application is shown.
[0034] Fig.11 A field curvature diagram of a far-infrared optical system in an embodiment of the present application is shown.
[0035] Fig.12 A distortion diagram of a far-infrared optical system in an embodiment of the present application is shown.
[0036] Reference numerals
[0037] 100. Far infrared optical system;
[0038] 1. The first aspheric lens;
[0039] 2. Super lens; 21. Substrate; 22. Micro-nano structure;
[0040] 3. Second aspheric lens;
[0041] 4. Aperture;
[0042] 5. Protective parts;
[0043] A, object plane; B, image plane; S, optical axis. DETAILED DESCRIPTION
[0044] Example embodiments will now be described more fully with reference to the accompanying drawings. However, example embodiments can be implemented in a variety of 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 concepts of the example embodiments will be fully conveyed to those skilled in the art. The accompanying drawings are only schematic illustrations of the present application and are not necessarily drawn to scale. The same reference numerals in the figures represent the same or similar parts, and thus their repeated description will be omitted.
[0045] In addition, the described features, structures or characteristics may 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 solution of the present application may be practiced while omitting one or more of the specific details, or other modules, components, etc. may be adopted. In other cases, known structures, methods, implementations or operations are not shown or described in detail to avoid obscuring the present application and making the various aspects of the present application obscure.
[0046] See also Figure 1 , Figure 1 FIG. 1 shows a schematic diagram of the architecture layout of a far-infrared optical system 100 in an embodiment of the present application, wherein the optical axis S is the center line of the light beam. Figure 1 In the figure, the object to be measured 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 plane 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 plane B is located on the image side. Therefore, the direction from the object plane A to the image plane B along the optical axis S is consistent with the direction from the object side to the image side along the optical axis S.
[0047] The far-infrared optical system 100 includes a first aspheric lens 1, a super lens 2, and a second aspheric lens 3. The first aspheric lens 1, the super lens 2, and the second aspheric lens 3 are arranged in sequence along the optical axis S from the object plane A to the image plane B.
[0048] The first aspheric lens 1 is a negative lens. The surface of the first aspheric lens 1 close to the object side is convex toward the object side, and the surface of the first aspheric lens 1 close to the image side is convex toward the object side.
[0049] The second aspheric lens 3 is a positive lens. The surface of the second aspheric lens 3 close to the object side is convex toward the image side, and the surface of the second aspheric lens 3 close to the image side is convex toward the image side.
[0050] The optical focal length of the superlens 2 is positive. The superlens 2 includes a substrate 21 and a superstructure unit located on the surface of the substrate 21. The vertex and / or center of the superstructure unit are provided with a micro-nanostructure 22. The micro-nanostructure 22 is respectively provided on the surface of the substrate 21 facing the object side and the surface of the substrate 21 facing the image side, that is, the superlens 2 is a double-sided superlens 2. The surface of the superlens 2 close to the object side is the front surface, and the front surface of the superlens 2 includes the substrate 21 and the micro-nanostructure 22 provided on the surface of the substrate 21 close to the object side. The surface of the superlens 2 close to the image side is the rear surface, and the rear surface of the superlens 2 includes the substrate 21 and the micro-nanostructure 22 provided on the surface of the substrate 21 close to the image side.
[0051] In the prior art, superlenses are usually produced using semiconductor processes, which have great cost advantages over traditional lenses. However, superlenses usually introduce a certain amount of dispersion, which is not conducive to controlling the aberration of the system. If additional lenses are provided, the production cost of the optical system will increase and the volume of the system will also increase.
[0052] In the present application, the optical focal length of the front surface of the metalens 2 and the optical focal length of the rear surface of the metalens 2 are opposite in sign, that is, the optical focal length of any one of the front surface of the metalens 2 and the rear surface of the metalens 2 is a positive value, and the optical focal length of the other of the front surface of the metalens 2 and the rear surface of the metalens 2 is a negative value. Therefore, the front surface of the metalens 2 and the rear surface of the metalens 2 are complementary, and the metalens 2 can eliminate a certain chromatic aberration of itself, and can avoid the metalens 2 from introducing excessive chromatic aberration, which is beneficial to controlling the aberration of the far-infrared optical system 100.
[0053] In the present application, the optical focal power of the front surface of the metalens 2 and the optical focal power of the rear surface of the metalens 2 are opposite in positive and negative, the front surface of the metalens 2 and the rear surface of the metalens 2 are complementary, the metalens 2 can eliminate a certain chromatic aberration of itself, and the optical focal power of the first aspheric lens 1 and the second aspheric lens 3 are opposite. Through the combination of the first aspheric lens 1, the metalens 2 and the second aspheric lens 3, the far-infrared optical system 100 has a higher imaging quality. The number of lenses of the far-infrared optical system 100 is small, which is conducive to controlling the cost of lens materials, and the metalens 2 can be produced by semiconductor technology. The cost of a single metalens 2 is low in mass production, which can further reduce the production cost of the far-infrared optical system 100. At the same time, the total optical length of the far-infrared optical system 100 is relatively short. That is, the far-infrared optical system 100 provided by the present application compresses the system volume and production cost to a certain extent while ensuring the imaging quality.
[0054] In some embodiments, the optical power of the front surface of the superlens 2 is a negative value, the optical power of the rear surface of the superlens 2 is a positive value, and the optical power of the superlens 2 as a whole is a positive value.
[0055] In some embodiments, the optical power of the front surface of the metalens 2 is positive, the optical power of the rear surface of the metalens 2 is negative, and the optical power of the metalens 2 as a whole is positive.
[0056] In some embodiments, the micro-nano structure 22 is a negative micro-nano structure 22 .
[0057] In some embodiments, the micro-nano structure 22 is a positive micro-nano structure 22 .
[0058] In some embodiments, the micro-nano structure 22 is provided with a layer to adapt the processing technology of the superlens 2 to the existing semiconductor process, thereby facilitating the processing and manufacturing of the superlens 2.
[0059] In some embodiments, the micro-nano structure 22 is provided with two or more layers, and each layer of the micro-nano structure 22 can be configured separately so that the metalens 2 can easily achieve the expected performance while having a higher degree of design freedom.
[0060] It should be noted that the number of layers of the micro-nano structure 22 on the surface of the substrate 21 close to the object side and the number of layers of the micro-nano structure 22 on the surface of the substrate 21 close to the image side can be equal or unequal, as long as the superlens 2 has the expected optical performance.
[0061] In some embodiments, the phase distribution of the metalens 2 satisfies the following formula:
[0062]
[0063] Wherein, r is the distance from the center of the superlens 2 to any micro-nanostructure 22, λ is the central wavelength of the working band of the superlens 2, is the phase constant, (x, y) is the two-dimensional coordinate of the surface of the superlens 2, and f m is the focal length of the metalens 2; ai and bi are real coefficients.
[0064] In some embodiments, the far-infrared optical system 100 satisfies Conditional Formula 1: Wherein, f is the effective focal length of the far-infrared optical system 100, and the dimension of f is the unit of length. FOV (Field of View, FOV for short) is the maximum field of view of the far-infrared optical system 100. D is the entrance pupil diameter of the far-infrared optical system 100, and the dimension of D is the unit of length. TTL (Total Track Length, TTL for short) is the total optical length of the far-infrared optical system 100, and the dimension of TTL is the unit of length. In the present application, TTL is the distance between the surface of the first aspheric lens 1 close to the object side and the image plane B on the optical axis S. The dimensions of f, D, and TTL are the same, and they are all units of length, such as millimeters.
[0065] The upper limit of conditional formula 1 ensures the amount of light entering the far-infrared optical system 100, so that the image formed by the far-infrared optical system 100 has higher brightness and clearer details. The lower limit of conditional formula 1 ensures that the far-infrared optical system 100 has a sufficiently large field of view and a small volume.
[0066] In some embodiments, the far-infrared optical system 100 satisfies conditional formula 2: Among them, BFL (Back Focal Length, referred to as BFL) is the optical back focal length of the far-infrared optical system 100. In the present application, BFL is the distance between the surface of the second aspheric lens 3 close to the image side and the image plane B on the optical axis S. The dimension of BFL is the unit of length. Wis the working F number of the far-infrared optical system 100. D is the entrance pupil diameter of the far-infrared optical system 100, and the dimension of D is the unit of length. TTL is the total optical length of the far-infrared optical system 100, and the dimension of TTL is the unit of length. BFL, D, and TTL have the same dimension, which is the unit of length, such as millimeters.
[0067] The upper limit of conditional expression 2 ensures that the far-infrared optical system 100 has more light input and better imaging quality. The lower limit of conditional expression 2 ensures that the far-infrared optical system 100 has a suitable optical back focal length, which can ensure that the far-infrared optical system 100 can be assembled smoothly.
[0068] In some embodiments, the far-infrared optical system 100 satisfies conditional formula 3: Among them, d 1 is the effective aperture of the first aspherical lens 1, specifically, d 1 is the diameter of the light-transmitting area of the first aspherical lens 1, d 1 The dimension of is the unit of length. g1 is the paraxial focal length of the first aspheric lens 1, f g1 The dimension of is the unit of length. 2 is the effective aperture of the second aspherical lens 3. Specifically, d 2 is the diameter of the light-transmitting area of the second aspherical lens 3, d 2 The dimension of is the unit of length. g2 is the paraxial focal length of the second aspheric lens 3, f g2 The dimension of is the unit of length. 1 、f g1 ,d 2 、f g2 have the same dimension, which is a unit of length, such as millimeter.
[0069] The upper limit of conditional expression 3 can prevent the effective aperture of the first aspheric lens 1 and the effective aperture of the second aspheric lens 3 from exceeding the limit. The lower limit of conditional expression 3 can ensure that the first aspheric lens 1 and the second aspheric lens 3 have a certain optical power, so that the far-infrared optical system 100 formed by the first aspheric lens 1, the second aspheric lens 3 and the metalens 2 has better imaging quality.
[0070] In some embodiments, the far-infrared optical system 100 satisfies Condition 4: in, is the phase distribution of any one of the front surface of the superlens 2 and the rear surface of the superlens 2, The unit is rad, is the phase change amount of any one of the front surface of the super lens 2 and the rear surface of the super lens 2. is the phase distribution of the other of the front surface of the superlens 2 and the rear surface of the superlens 2, The unit is rad, The phase change amount of the other of the front surface of the metalens 2 and the rear surface of the metalens 2. r is the distance from the center of the metalens 2 to any point in the effective area of the metalens 2. In the present application, the effective area of the metalens 2 refers to the area where the micro-nano structure 22 is provided on the metalens 2. The unit of r is the unit of length. dr is the change amount of the distance from the center of the metalens 2 to any point in the effective area of the metalens 2.
[0071] The upper limit of conditional formula 4 ensures that the optical focal length of the front surface of the metalens 2 and the optical focal length of the rear surface of the metalens 2 are complementary to a certain extent, so that the metalens 2 itself can correct a certain chromatic aberration, avoid the metalens 2 introducing a large chromatic aberration, and ensure the imaging quality of the far-infrared optical system 100. The lower limit of conditional formula 4 ensures that the metalens 2 has a certain optical focal length, so that the metalens 2 has a certain focusing ability.
[0072] In some embodiments, the far-infrared optical system 100 satisfies Condition 5: Wherein, f is the effective focal length of the far-infrared optical system 100, and the dimension of f is the unit of length. m is the focal length of the superlens 2, f m The dimension of is the unit of length. m , f have the same dimension, both are length units, such as millimeters.
[0073] Conditional formula five characterizes the ratio of the effective focal length of the far-infrared optical system 100 to the focal length of the metalens 2. In the present application, the metalens 2 has less optical focal length in the far-infrared optical system 100, and the main function of the metalens 2 is to provide aberration compensation for the full field of view. The lower limit of conditional formula five can ensure that the metalens 2 plays a certain role in focusing or diverging light in the far-infrared optical system 100. In addition, the lower limit of conditional formula five reduces the curvature of the first aspheric lens 1 and the second aspheric lens 3 to a certain extent, ensuring that the first aspheric lens 1 and the second aspheric lens 3 have good machinability. The upper limit of conditional formula five can avoid the optical focal length of the metalens 2 being too large, thereby avoiding the far-infrared optical system 100 from having large chromatic aberration in a wide spectral band.
[0074] In some embodiments, the far-infrared optical system 100 satisfies conditional formula 6: Among them, d 2 is the effective aperture of the second aspherical lens 3, d 2 The dimension of is length unit. 2 is the center thickness of the second aspheric lens 3, i.e. CT 2is the thickness of the second aspheric lens 3 on the optical axis S, CT 2 The dimension of F is the unit of length. W is the working F number of the far-infrared optical system 100. D is the entrance pupil diameter of the far-infrared optical system 100, and the dimension of D is the unit of length. FOV is the maximum field of view of the far-infrared optical system 100.
[0075] Conditional formula six is used to ensure that the effective aperture of the far-infrared optical system 100, the volume of each lens, and the size of the image plane B of the far-infrared optical system 100 are all within a reasonable range. Specifically, the upper limit of conditional formula six limits the effective aperture of the optical system and the volume of each lens from being too large, thereby ensuring that the volume of the far-infrared optical system 100 is relatively small, which is conducive to the miniaturization of the far-infrared optical system 100 and can also reduce the material cost of the lens. The lower limit of conditional formula six can ensure that the size of the image plane B of the far-infrared optical system 100 and the entrance pupil diameter meet the preset specifications and are adapted to the field of view.
[0076] In some embodiments, the far-infrared optical system 100 satisfies conditional equation 7: Among them, n F is the refractive index of the first aspherical lens 1, FOV is the maximum field angle of the far-infrared optical system 100. EPD is the exit pupil diameter of the far-infrared optical system 100, and the dimension of EPD is the unit of length. F1 is the radius of curvature of the surface of the first aspheric lens 1 close to the object side, R F1 The dimension of R is the unit of length. F1 , EPD have the same dimension, both are length units, such as millimeters.
[0077] The upper limit of conditional expression 7 can prevent the curvature radius of the surface of the first aspheric lens 1 close to the object side from being too large and difficult to process, and the lower limit of conditional expression 7 can ensure that the entrance pupil diameter and the field angle of the far-infrared optical system 100 meet the expected values.
[0078] In some embodiments, the far-infrared optical system 100 satisfies Conditional Formula 8: Among them, R L1 is the curvature radius of the surface of the second aspherical lens 3 close to the object side, R L1 The dimension of R is the unit of length. L2 is the curvature radius of the surface of the second aspheric lens 3 close to the image side, R L2 The dimension of R is the unit of length. L2 , R L1 have the same dimension, both are length units, such as millimeters. L1 is the conic coefficient of the surface of the second aspheric lens 3 close to the object side, K L2 is the conic coefficient of the surface of the second aspherical lens 3 close to the image side.
[0079] Conditional formula eight characterizes the processing difficulty and light focusing ability of the second aspheric lens 3. Specifically, the lower limit of conditional formula eight can ensure that the difference between the curvature radius of the surface of the second aspheric lens 3 close to the object side and the curvature radius of the surface of the second aspheric lens 3 close to the image side is within a reasonable range, thereby ensuring that the second aspheric lens 3 has good processability. The upper limit of conditional formula eight can ensure that the second aspheric lens 3 has the expected focusing ability, which helps to reduce the aberration of the far-infrared optical system 100 and control the optical back focal length of the far-infrared optical system 100 to have a suitable size.
[0080] In some embodiments, the far-infrared optical system 100 satisfies Condition 9: Wherein, TTL is the total optical length of the far-infrared optical system 100, and the dimension of TTL is the unit of length. 2 is the effective aperture of the second aspherical lens 3, d 2 The dimension of is length unit. 1 is the center thickness of the first aspheric lens 1, i.e. CT 1 is the thickness of the first aspheric lens 1 on the optical axis S, CT 1 The dimension of is length unit. 2 is the center thickness of the second aspheric lens 3, i.e. CT 2 is the thickness of the second aspheric lens 3 on the optical axis S, CT 2 The dimension is the unit of length. TTL, d 2 , CT 1 , CT 2 have the same dimension, which is a unit of length, such as millimeter.
[0081] The upper limit of conditional formula nine is used to limit the total optical length and aperture of the far-infrared optical system 100. Limiting the total optical length of the far-infrared optical system 100 can ensure that the far-infrared optical system 100 has thicker lenses to a certain extent, and thicker lenses help reduce the field curvature of the far-infrared optical system 100. The lower limit of conditional formula nine can ensure that the lenses of the far-infrared optical system 100 are not too thick, thereby leaving space for the air gap between the lenses to ensure the structure and imaging quality of the far-infrared optical system 100.
[0082] In some embodiments, the far-infrared optical system 100 satisfies Conditional Formula 10: Wherein, TTL is the total optical length of the far-infrared optical system 100, and the dimension of TTL is the unit of length. m is the focal length of the superlens 2, f m The dimension of F is the unit of length. Wis the working F number of the far-infrared optical system 100. D is the entrance pupil diameter of the far-infrared optical system 100, and the dimension of D is the unit of length. m , D have the same dimension, both are units of length.
[0083] Condition 10 represents the contribution of the metalens 2 to reducing the volume of the far-infrared optical system 100. The lower limit of Condition 10 is the minimum contribution of the metalens 2 in reducing the volume of the far-infrared optical system 100, and the upper limit of Condition 10 is the maximum contribution of the metalens 2 in reducing the volume of the far-infrared optical system 100.
[0084] In some embodiments, the far-infrared optical system 100 further includes an aperture 4, which is used to limit the amount of light entering the far-infrared optical system 100 to ensure that the far-infrared optical system 100 can work effectively and generate high-quality images. The position of the aperture 4 can be any of the following:
[0085] (1) The aperture 4 is provided on the object side of the first aspherical lens 1 .
[0086] (2) The aperture 4 is provided between the first aspherical lens 1 and the super lens 2 .
[0087] (3) The aperture 4 is provided between the super lens 2 and the second aspherical lens 3 .
[0088] Furthermore, in some embodiments, the aperture 4 is disposed between the first aspheric lens 1 and the superlens 2 so that the far-infrared optical system 100 has better imaging quality.
[0089] In some embodiments, the far-infrared optical system 100 further includes a protective member 5, which can transmit light, and is located on a side of the second aspheric lens 3 away from the super lens 2 along the optical axis S. The protective member 5 may be in the form of protective glass, but the material of the protective member 5 is not limited to silicon, and illustratively, the material of the protective member 5 may also be germanium.
[0090] The present application exemplarily provides three far-infrared optical systems 100 that meet usage requirements in three embodiments. Next, the far-infrared optical systems 100 provided by the various embodiments of the present application are introduced in detail.
[0091] Example 1
[0092] Figure 1 FIG. 1 shows a schematic diagram of the architecture layout of the far-infrared optical system 100 provided in Example 1. Figure 1The mid-infrared optical system 100 includes, along the optical axis S, from the object plane A to the image plane B, a first aspheric lens 1, an aperture 4, a super lens 2, a second aspheric lens 3 and a protective member 5, wherein the protective member 5 is a protective glass. Some parameters of the far-infrared optical system 100 in Example 1 are shown in Table 1.
[0093] Table 1. Partial parameters of the far-infrared optical system 100 in Example 1
[0094] parameter data Total optical length (TTL) 20.00mm Maximum field of view (2ω) 64° F-number 0.949 Effective focal length 9.24mm Working band Far infrared (8000nm-12000nm)
[0095] As can be seen from Table 1, the total optical length of the far-infrared optical system 100 in this embodiment is 20.00 mm. The F number of the far-infrared optical system 100 in this embodiment is 0.949, which can greatly increase the amount of light entering the far-infrared optical system 100, and collect as much energy as possible entering the far-infrared optical system 100 when the image sensor has a low response to light energy, thereby ensuring excellent imaging quality. The effective focal length of the far-infrared optical system 100 in this embodiment is 9.24 mm.
[0096] Starting from the object plane A, along the optical axis S from the object plane A to the image plane B, each surface in the far-infrared optical system 100 is numbered, and the parameters of each surface are summarized to obtain the following Table 2.
[0097] Table 2. Parameters of various surfaces in the far-infrared optical system 100 provided in Example 1
[0098] Surface serial number Surface type Curvature radius (mm) Thickness(mm) Material refractive index 0 Physical surface unlimited - - 1 Aspheric 6.38 1.31 2.78 2 Aspheric 5.41 2.26 - 3 Aperture unlimited 0.39 - 4 Spherical surface (hypersurface) unlimited 0.30 3.42 5 Spherical surface (hypersurface) unlimited 1.08 - 6 Aspheric -41.62 6.20 2.77 7 Aspheric -14.09 6.97 - 8 Spherical unlimited 1.00 4.00 9 Spherical unlimited 0.50 - 10 Image plane unlimited - -
[0099] For each surface in Table 2, surface 0 is object surface A. Surface 1 is the surface of the first aspheric lens 1 close to the object side, and surface 2 is the surface of the first aspheric lens 1 close to the image side. Surface 3 is aperture 4, surface 4 is the surface of the super lens 2 close to the object side, and surface 5 is the surface of the super lens 2 close to the image side. Surface 6 is the surface of the second aspheric lens 3 close to the object side, and surface 7 is the surface of the second aspheric lens 3 close to the image side. Surface 8 is the surface of the protective member 5 close to the object side, and surface 9 is the surface of the protective member 5 close to the image side. Surface 10 is image surface B.
[0100] As can be seen from Table 2, the radius of curvature of surface 0 is infinite, that is, surface 0 is a plane, the distance between surface 0 and surface 1 is uncertain, and the material between surface 0 and surface 1 is air. Surface 1 is an aspherical surface, the radius of curvature of surface 1 is 6.38 mm, the distance between surface 1 and surface 2 is 1.31 mm, and the refractive index of the material between surface 1 and surface 2 is 2.78. Surface 2 is an aspherical surface, the radius of curvature of surface 2 is 5.41 mm, the distance between surface 2 and surface 3 is 2.26 mm, and the material between surface 2 and surface 3 is air. The radius of curvature of surface 3 is infinite, that is, surface 3 is a plane, the distance between surface 3 and surface 4 is 0.39 mm, and the material between surface 3 and surface 4 is air. The micro-nano structure 22 is provided on surface 4 and surface 5, so surface 4 and surface 5 are both recorded as super surfaces, 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 0.30 mm, and the refractive index of the material between surface 4 and surface 5 is 3.42. 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 1.08 mm, and the material between surface 5 and surface 6 is air. Surface 6 is an aspherical surface, the radius of curvature of surface 6 is -41.62 mm, the distance between surface 6 and surface 7 is 6.20 mm, and the refractive index of the material between surface 6 and surface 7 is 2.77. Surface 7 is an aspherical surface, the radius of curvature of surface 7 is -14.09 mm, the distance between surface 7 and surface 8 is 6.97 mm, and the material between surface 7 and surface 8 is air. The radius of curvature of surface 8 is infinite, that is, surface 8 is a plane, the distance between surface 8 and surface 9 is 1.00 mm, and the refractive index of the material between surface 8 and surface 9 is 4.00. The radius of curvature of surface 9 is infinite, that is, surface 9 is a plane, the distance between surface 9 and surface 10 is 0.50 mm, and the material between surface 9 and surface 10 is air.
[0101] Surface 1, surface 2, surface 6 and surface 7 are even-order aspheric surfaces, and their surface shapes satisfy the following relationship:
[0102]
[0103] Among them, Z(r) is the distance vector height from the vertex of the aspheric surface when the aspheric surface is at a height of r along the optical axis S direction; c is the curvature of the aspheric surface, c=1 / R, R is the curvature radius of the aspheric surface; k is the cone coefficient; A, B, C, D are the aspheric coefficients. The values of k, A, B, C, D of surface 1, surface 2, surface 6 and surface 7 can be obtained from Table 3.
[0104] Table 3. Coefficients of the even-order aspheric surfaces in the far-infrared optical system 100 provided in Example 1
[0105] Surface serial number K A B C D 1 -5.44E-001 2.49E-004 -4.28E-005 1.22E-006 6.99E-008 2 -1.27E+000 1.10E-003 -1.22E-004 1.25E-005 -8.89E-007 6 -1.00E+002 -1.48E-004 -1.62E-005 3.66E-006 -2.61E-007 7 -3.08E+000 -1.81E-004 1.65E-006 -1.18E-009 -3.44E-009
[0106] Referring to Table 3, for surface 1, K is -5.44E-001, A is 2.49E-004, B is -4.28E-005, C is 1.22E-006, and D is 6.99E-008. The values of k, A, B, C, and D for surfaces 2, 6, and 7 are not repeated again.
[0107] See also Figure 2 , Figure 2 The MTF (Modulation Transfer Function, MTF for short) field of view curve of the far-infrared optical system 100 provided in Example 1 is shown. Figure 2 The horizontal axis in is the X-axis field of view angle, and its unit is degree. Figure 2 The vertical axis in is the MTF value. MTF, also known as modulation transfer function, is an important indicator used to describe the imaging quality of an optical system. The larger the MTF value, the better the imaging quality. Figure 2 The sagittal image curve S1 and the meridional image curve T1 of the MTF of 10lp / mm spatial frequency as it changes with the field of view, the sagittal image curve S2 and the meridional image curve T2 of the MTF of 21lp / mm spatial frequency as it changes with the field of view, and the sagittal image curve S3 and the meridional image curve T3 of the MTF of 42lp / mm spatial frequency as it changes with the field of view are listed.
[0108] Depend on Figure 2 It can be seen that within the full field of view, the MTF is greater than 0.2, and within the 0.7 field of view (22.4°), the MTF is greater than 0.4. Therefore, the far-infrared optical system 100 provided in Example 1 has excellent imaging quality. Figure 2 There is little difference between the MTF of 0 field of view (center of the picture) and the MTF of 1.0 field of view (32°) at the same spatial frequency, indicating that the field curvature of the far-infrared optical system 100 is better controlled and the overall imaging quality is better.
[0109] See also Figure 3 , Figure 3 1 shows a field curvature diagram of the far-infrared optical system 100 provided in Example 1, Figure 3 The horizontal axis is the field curvature, and its unit is millimeter. Figure 3 The vertical coordinate is the field of view angle, and its unit is degree. Figure 3 The T1, T2, and T3 curves are the field curvatures of infrared light with wavelengths of 8 microns, 10 microns, and 12 microns in the meridional direction, and the S1, S2, and S3 curves are the field curvatures of infrared light with wavelengths of 8 microns, 10 microns, and 12 microns in the sagittal direction. Figure 3 It can be seen that the maximum field curvature of the far-infrared optical system 100 in the sagittal direction is 0.0880 mm, and the maximum field curvature of the far-infrared optical system 100 in the meridional direction is 0.1096 mm, which meets the requirements for field curvature in the excellent imaging quality standard.
[0110] See also Figure 4 , Figure 4 The distortion diagram of the far-infrared optical system 100 provided in Example 1 under infrared light with wavelengths of 8 microns, 9 microns, 10 microns, 11 microns, and 12 microns is shown. Figure 4 The horizontal axis is the percentage of distortion. Figure 4 The vertical axis is the field of view angle, in degrees. Figure 4 The spacing between the five curves in is too small, so that the five curves almost overlap, so the five curves are not distinguished. Figure 4 It can be seen that the maximum distortion is 13.51%.
[0111] Example 2
[0112] Figure 5 FIG. 1 shows a schematic diagram of the architecture layout of the far-infrared optical system 100 provided in Example 2. Figure 5 The mid-infrared optical system 100 includes, along the optical axis S, from the object plane A to the image plane B, a first aspheric lens 1, an aperture 4, a super lens 2, a second aspheric lens 3, and a protective member 5, wherein the protective member 5 is a protective glass. Some parameters of the far-infrared optical system 100 in Example 2 are shown in Table 4.
[0113] Table 4. Partial parameters of the far-infrared optical system 100 in Example 2
[0114]
[0115]
[0116] As can be seen from Table 4, the total optical length of the far-infrared optical system 100 in this embodiment is 20.49 mm. The F number of the far-infrared optical system 100 in this embodiment is 1.030, which can greatly increase the amount of light entering the far-infrared optical system 100, and collect as much energy as possible entering the far-infrared optical system 100 when the image sensor has a low response to light energy, thereby ensuring excellent imaging quality. The effective focal length of the far-infrared optical system 100 in this embodiment is 9.36 mm.
[0117] Starting from the object plane A, along the optical axis S from the object plane A to the image plane B, each surface in the far-infrared optical system 100 is numbered, and the parameters of each surface are summarized to obtain the following Table 5.
[0118] Table 5. Parameters of various surfaces in the far-infrared optical system 100 provided in Example 2
[0119] Surface serial number Surface type Curvature radius (mm) Thickness(mm) Material refractive index 0 Physical surface unlimited - - 1 Aspheric 6.99 2.02 - 2 Aspheric 5.65 2.36 2.77 3 Aperture unlimited 0.05 - 4 Spherical surface (hypersurface) unlimited 0.30 3.42 5 Spherical surface (hypersurface) unlimited 0.61 - 6 Aspheric -50.01 6.19 2.77 7 Aspheric -11.57 7.57 - 8 Spherical unlimited 1.00 4.00 9 Spherical unlimited 0.50 - 10 Image plane unlimited - -
[0120] The analysis of each surface in Table 5 can refer to Example 1 and will not be repeated here.
[0121] Surface 1, surface 2, surface 6 and surface 7 are even-order aspheric surfaces, and their surface shapes satisfy the following relationship:
[0122]
[0123] Among them, Z(r) is the distance vector height from the vertex of the aspherical surface when the aspherical surface is at a height of r along the optical axis S direction; c is the surface curvature of the aspherical surface, c=1 / R, R is the curvature radius of the aspherical surface; k is the cone coefficient; A, B, C, D are the aspherical coefficients. The values of k, A, B, C, D of surface 1, surface 2, surface 6 and surface 7 can be obtained from Table 6.
[0124] Table 6. Coefficients of the even-order aspheric surfaces in the far-infrared optical system 100 provided in Example 2
[0125]
[0126]
[0127] The method of querying the coefficients of the even-order aspheric surfaces of surface 1, surface 2, surface 6, and surface 7 through Table 6 can refer to Example 1, which will not be repeated here.
[0128] See also Figure 6 , Figure 6 FIG. 2 shows the MTF field curve of the far-infrared optical system 100 provided in Example 2. Figure 6 The horizontal axis in is the X-axis field of view angle, and its unit is degree. Figure 6 The vertical axis is the MTF value. Figure 6 The sagittal image curve S1 and the meridional image curve T1 of the MTF of 10lp / mm spatial frequency as it changes with the field of view, the sagittal image curve S2 and the meridional image curve T2 of the MTF of 21lp / mm spatial frequency as it changes with the field of view, and the sagittal image curve S3 and the meridional image curve T3 of the MTF of 42lp / mm spatial frequency as it changes with the field of view are listed.
[0129] Depend on Figure 6 It can be seen that the MTF is greater than 0.3 within the 0.9 field of view (28.8°). Therefore, the far-infrared optical system 100 provided in Example 2 has excellent imaging quality.
[0130] See also Figure 7 , Figure 7 2 shows a field curvature diagram of the far-infrared optical system 100 provided in Example 2, Figure 7 The horizontal axis is the field curvature, and its unit is millimeter. Figure 7 The vertical coordinate is the field of view angle, and its unit is degree. Figure 7 The T1, T2, and T3 curves are the field curvatures of infrared light with wavelengths of 8 microns, 10 microns, and 12 microns in the meridional direction, and the S1, S2, and S3 curves are the field curvatures of infrared light with wavelengths of 8 microns, 10 microns, and 12 microns in the sagittal direction. Figure 7 It can be seen that the maximum field curvature of the far-infrared optical system 100 in the sagittal direction is 0.0507 mm, and the maximum field curvature of the far-infrared optical system 100 in the meridional direction is 0.0214 mm, which meets the requirements for field curvature in the excellent imaging quality standard.
[0131] See also Figure 8 , Figure 8 The distortion diagram of the far-infrared optical system 100 provided in Example 2 under infrared light with wavelengths of 8 microns, 9 microns, 10 microns, 11 microns, and 12 microns is shown. Figure 8 The horizontal axis is the percentage of distortion. Figure 8 The vertical axis is the field of view angle, in degrees. Figure 8 The spacing between the five curves in is too small, so that the five curves almost overlap, so the five curves are not distinguished. Figure 8 It can be seen that the maximum distortion is 15.47%.
[0132] Example 3
[0133] Fig. 9 FIG. 1 shows a schematic diagram of the architecture layout of the far-infrared optical system 100 provided in Example 3. Fig. 9 The mid-infrared optical system 100 includes, along the optical axis S, from the object plane A to the image plane B, a first aspheric lens 1, an aperture 4, a super lens 2, a second aspheric lens 3, and a protective member 5, wherein the protective member 5 is a protective glass. Some parameters of the far-infrared optical system 100 in Example 3 are shown in Table 7.
[0134] Table 7. Partial parameters of the far-infrared optical system 100 in Example 3
[0135] parameter data Total optical length (TTL) 19.50mm Maximum field of view (2ω) 64° F-number 0.952 Effective focal length 9.47mm Working band Far infrared (8000nm-12000nm)
[0136] As can be seen from Table 7, the total optical length of the far-infrared optical system 100 in this embodiment is 19.50 mm. The F number of the far-infrared optical system 100 in this embodiment is 0.952, which can greatly increase the amount of light entering the far-infrared optical system 100, and collect as much energy as possible entering the far-infrared optical system 100 when the image sensor has a low response to light energy, thereby ensuring excellent imaging quality. The effective focal length of the far-infrared optical system 100 in this embodiment is 9.47 mm.
[0137] Starting from the object plane A, along the optical axis S from the object plane A to the image plane B, each surface in the far-infrared optical system 100 is numbered, and the parameters of each surface are summarized to obtain the following Table 8.
[0138] Table 8. Parameters of various surfaces in the far-infrared optical system 100 provided in Example 3
[0139] Surface serial number Surface type Curvature radius (mm) Thickness(mm) Refractive index of the material 0 Physical surface unlimited - - 1 Aspheric 6.36 2.07 2.78 2 Aspheric 5.04 2.34 - 3 Aperture unlimited 0.05 - 4 Spherical surface (hypersurface) unlimited 0.30 3.42 5 Spherical surface (hypersurface) unlimited 1.14 - 6 Aspheric -82.48 5.42 2.77 7 Aspheric -12.19 6.74 - 8 Spherical unlimited 1.00 4.00 9 Spherical unlimited 0.50 - 10 Image plane unlimited - -
[0140] The analysis of each surface in Table 8 can be referred to Example 1, which will not be repeated here.
[0141] Surface 1, surface 2, surface 6 and surface 7 are even-order aspheric surfaces, and their surface shapes satisfy the following relationship:
[0142]
[0143] Among them, Z(r) is the distance vector height from the vertex of the aspheric surface when the aspheric surface is at a height of r along the optical axis S direction; c is the surface curvature of the aspheric surface, c=1 / R, R is the curvature radius of the aspheric surface; k is the cone coefficient; A, B, C, D are the aspheric coefficients. The values of k, A, B, C, D of surface 1, surface 2, surface 6 and surface 7 can be obtained from Table 9.
[0144] Table 9. Coefficients of the even-order aspheric surfaces in the far-infrared optical system 100 provided in Example 3
[0145] Surface serial number K A B C D 1 -3.08E-001 3.02E-004 -1.99E-005 1.30E-006 5.68E-008 2 -9.22E-001 1.29E-003 -3.58E-005 1.33E-005 -1.17E-006 6 -9.78E+001 -2.61E-004 -1.91E-005 2.08E-006 -2.08E-007 7 -1.02E+000 -2.49E-004 3.67E-006 -2.89E-007 5.01E-009
[0146] The method of querying the coefficients of the even-order aspheric surfaces of surface 1, surface 2, surface 6, and surface 7 through Table 9 can refer to Example 1, which will not be repeated here.
[0147] See also Fig.10 , Fig.10 FIG. 1 shows the MTF field curve of the far-infrared optical system 100 provided in Example 3. Fig.10 The horizontal axis in is the X-axis field of view angle, and its unit is degree. Fig.10 The vertical axis is the MTF value. Fig.10 The sagittal image curve S1 and the meridional image curve T1 of the MTF of 10lp / mm spatial frequency as it changes with the field of view, the sagittal image curve S2 and the meridional image curve T2 of the MTF of 21lp / mm spatial frequency as it changes with the field of view, and the sagittal image curve S3 and the meridional image curve T3 of the MTF of 42lp / mm spatial frequency as it changes with the field of view are listed.
[0148] Depend on Fig.10 It can be seen that within the 0.8 field of view (26.5°), the MTF is greater than 0.2. Therefore, the imaging quality of the far-infrared optical system 100 provided in Example 3 is better. Fig.10 The difference between the sagittal curve and the meridional curve at the same spatial frequency is not large, indicating that the astigmatism control of the far-infrared optical system 100 is excellent.
[0149] See also Fig.11 , Fig.11 1 shows a field curvature diagram of the far-infrared optical system 100 provided in Example 3, Fig.11 The horizontal axis is the field curvature, and its unit is millimeter. Fig.11 The vertical coordinate is the field of view angle, and its unit is degree. Fig.11 The T1, T2, and T3 curves are the field curvatures of infrared light with wavelengths of 8 microns, 10 microns, and 12 microns in the meridional direction, and the S1, S2, and S3 curves are the field curvatures of infrared light with wavelengths of 8 microns, 10 microns, and 12 microns in the sagittal direction. Fig.11 It can be seen that the maximum field curvature of the far-infrared optical system 100 in the sagittal direction is 0.1763 mm, and the maximum field curvature of the far-infrared optical system 100 in the meridional direction is 0.2264 mm, which meets the requirements for field curvature in the excellent imaging quality standard.
[0150] See also Fig.12 , Fig.12 The distortion diagram of the far-infrared optical system 100 provided in Example 3 under infrared light with wavelengths of 8 microns, 9 microns, 10 microns, 11 microns, and 12 microns is shown. Fig.12 The horizontal axis is the percentage of distortion. Fig.12 The vertical axis is the field of view angle, in degrees. Fig.12 The spacing between the five curves in is too small, so that the five curves almost overlap, so the five curves are not distinguished. Fig.12 It can be seen that the maximum distortion is 16.99%.
[0151] After summarizing the various parameters of the far-infrared optical system 100 provided by the above three embodiments, the following Table 10 is obtained. Table 10 is mainly used to illustrate that the various conditions satisfied by the far-infrared optical system 100 provided by the present application are all verified and supported by experiments.
[0152] Table 10. Parameters of the far-infrared optical system 100 provided in various embodiments
[0153]
[0154]
[0155] The present application also provides a far-infrared optical lens (not shown), which includes an imaging detector (not shown) and the above-mentioned far-infrared optical system 100. The imaging detector is arranged on the image plane B of the far-infrared optical system 100, and the imaging detector includes but is not limited to CMOS (Complementary Metal Oxide Semiconductor, referred to as CMOS, complementary metal oxide semiconductor) and CCD (Charge Coupled Device, referred to as CCD, charge coupled device).
[0156] Those skilled in the art will readily appreciate 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 modification, use or adaptation of the present application, which follows the general principles of the present application and includes common knowledge or customary techniques in the art that are not disclosed in the present application. The specification and examples are intended to be exemplary only, and the true scope and spirit of the present application are indicated by the appended claims.
Claims
1. A far-infrared optical system, characterized in that: The far-infrared optical system includes, from the object side to the image side along the optical axis, a first aspheric lens, a super lens, and a second aspheric lens, wherein the first aspheric lens is a negative lens, and the surface of the first aspheric lens close to the object side and the surface of the first aspheric lens close to the image side are both convex toward the object side; the second aspheric lens is a positive lens, and the surface of the second aspheric lens close to the object side and the surface of the second aspheric lens close to the image side are both convex toward the image side; The superlens comprises a substrate and a micro-nano structure, wherein the micro-nano structure is respectively arranged on the surface of the substrate facing the object side and the surface of the substrate facing the image side; the surface of the superlens close to the object side is the front surface, and the surface of the superlens close to the image side is the rear surface, the optical focal length of the front surface of the superlens is opposite to the optical focal length of the rear surface of the superlens, and the optical focal length of the superlens is positive.
2. The far-infrared optical system according to claim 1, characterized in that: The far-infrared optical system meets the following requirements: Among them, f is the effective focal length of the far-infrared optical system, FOV is the maximum field of view angle of the far-infrared optical system, D is the entrance pupil diameter of the far-infrared optical system, and TTL is the total optical length of the far-infrared optical system.
3. The far-infrared optical system according to claim 1, 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 F W is the working F number of the far-infrared optical system, D is the entrance pupil diameter of the far-infrared optical system, and TTL is the total optical length of the far-infrared optical system.
4. The far-infrared optical system according to claim 1, characterized in that: The far-infrared optical system meets the following requirements: Wherein, d1 is the effective aperture of the first aspheric lens, and f g1 is the paraxial focal length of the first aspheric lens, d2 is the effective aperture of the second aspheric lens, and f g2 is the paraxial focal length of the second aspheric lens.
5. The far-infrared optical system according to claim 1, characterized in that: The far-infrared optical system meets the following requirements: Among them, the is the phase distribution of any one of the front surface of the super lens and the rear surface of the super lens, is the phase distribution of the other of the front surface of the superlens and the rear surface of the superlens, and r is the distance between any point in the effective area of the superlens and the center of the superlens.
6. The far-infrared optical system according to claim 1, 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 f m is the focal length of the metalens.
7. The far-infrared optical system according to claim 1, characterized in that: The far-infrared optical system meets the following requirements: Wherein, d2 is the effective aperture of the second aspheric lens, CT2 is the center thickness of the second aspheric lens, and F W is the working F number of the far-infrared optical system, D is the entrance pupil diameter of the far-infrared optical system, and FOV is the maximum field of view angle of the far-infrared optical system.
8. The far-infrared optical system according to claim 1, characterized in that: The far-infrared optical system meets the following requirements: Among them, the n F is the refractive index of the first aspherical lens, the EPD is the exit pupil diameter of the far-infrared optical system, the FOV is the maximum field angle of the far-infrared optical system, and the R F1 is the radius of curvature of the surface of the first aspheric lens close to the object side.
9. The far-infrared optical system according to claim 1, characterized in that: The far-infrared optical system meets the following requirements: Among them, the R L1 is the radius of curvature of the surface of the second aspheric lens close to the object side, and the R L2 is the radius of curvature of the surface of the second aspheric lens close to the image side, and the K L1 is the conic coefficient of the surface of the second aspheric lens close to the object side, and the K L2 is the conic coefficient of the surface of the second aspheric lens close to the image side.
10. The far-infrared optical system according to claim 1, characterized in that: The far-infrared optical system meets the following requirements: Among them, the TTL is the total optical length of the far-infrared optical system, the d2 is the effective aperture of the second aspheric lens, the CT1 is the center thickness of the first aspheric lens, and the CT2 is the center thickness of the second aspheric lens.
11. The far-infrared optical system according to claim 1, 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 m is the focal length of the metalens, the F W is the working F number of the far-infrared optical system, and D is the entrance pupil diameter of the far-infrared optical system.
12. The far-infrared optical system according to any one of claims 1 to 11, characterized in that: The far-infrared optical system further comprises an aperture, which is arranged on a side of the first aspherical lens close to the object side; or, The aperture is disposed between the first aspheric lens and the super lens; or, The aperture is disposed between the super lens and the second aspherical lens.
13. A far-infrared optical lens, characterized in that: include: An imaging detector and a far-infrared optical system as claimed in any one of claims 1 to 12; The imaging detector is arranged on the image plane of the far-infrared optical system.