Far infrared optical system and far infrared optical lens
By designing a far-infrared optical system including refractive lenses and ultralens, and using the substrate of the ultralens instead of protective glass, the problems of large volume and high cost caused by the large number of optical components in the existing system are solved, and the effects of miniaturization, lightweighting and high integration are achieved.
Patent Information
- Application Number
- CN202422178533.0
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-09-05
- Publication Date
- 2025-06-10
- Estimated Expiration
- 2034-09-05
AI Technical Summary
The existing far-infrared optical systems include multiple optical components, including protective glass, which leads to larger system size, higher cost and lower integration.
A far-infrared optical system is designed, which includes a refractive lens and an ultralens in sequence along the optical axis from the object side to the image side. The substrate of the ultralens can replace the protective glass, reduce the number of optical components and improve the integration.
By reducing the number of optical components, the volume and cost of the far-infrared optical system are compressed, achieving the advantages of miniaturization and lightweighting, while improving the integration of the system.
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Figure CN222965481U_ABST
Abstract
Description
Technical Field
[0001] This application relates to the field of optical systems, and particularly to a far-infrared optical system and a far-infrared optical lens. Background Art
[0002] A far-infrared optical system refers to an optical system operating in the far-infrared band. The far-infrared optical system and the imaging detector are important components of a far-infrared optical lens.
[0003] To protect the imaging detector disposed on the image plane of the far-infrared optical system, in the prior art, the far-infrared optical system usually includes a protective glass, and the protective glass is generally disposed close to the image plane of the far-infrared optical system. Since the far-infrared optical system usually further includes a certain number of lenses in addition to the protective glass, and increasing the integration degree of the far-infrared optical system can generally reduce the volume and cost of the far-infrared optical system, therefore, the far-infrared optical system also needs to reduce the number of optical elements including the protective glass in the far-infrared optical system. Summary of the Utility Model
[0004] In view of the above technical problems, embodiments of this 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 and the far-infrared optical lens.
[0005] According to one aspect of the embodiments of this 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 metalens; the refractive lens has a positive optical power, the object side surface of the refractive lens bulges toward the object side, and the image side surface of the refractive lens bulges toward the image side; the metalens has a positive optical power, 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;
[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 metalens 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 f g is the focal length of the refractive lens, and the f m is the focal length of the metalens.
[0009] In some embodiments, the far-infrared optical system satisfies: Wherein, the R g1 is the radius of curvature of the object side surface of the refractive lens, and the Rg2 is the radius of curvature of the image side of the refractive lens, and the f is the effective focal length of the far-infrared optical system.
[0010] In some embodiments, the far-infrared optical system satisfies: wherein the CT g is the central thickness of the refractive lens, the n is the refractive index of the refractive lens, and the c g1 is the curvature of the object side of the refractive lens, and the c g2 is the curvature of the image side of the refractive lens.
[0011] 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.
[0012] 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 meta-lens.
[0013] In some embodiments, the diaphragm is disposed on the object side of the refractive lens, and the far-infrared optical system satisfies: wherein the L a2 is the distance between the image side of the refractive lens and the object side of the meta-lens on the optical axis, and the L a3 is the distance between the image side of the meta-lens and the image plane of the far-infrared optical system, and the TTL is the total optical length of the far-infrared optical system.
[0014] In some embodiments, the diaphragm is disposed on the object side of the refractive lens, and the far-infrared optical system satisfies: wherein the n is the refractive index of the refractive lens, the FOV is the maximum field of view angle of the far-infrared optical system, and the L a1 is the distance between the diaphragm and the object side of the refractive lens on the optical axis, and the R g1 is the radius of curvature of the object side of the refractive lens, and the CT g is the central thickness of the refractive lens.
[0015] A second aspect of the embodiments of the present application provides a far-infrared optical lens, and the far-infrared optical lens 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 this application sequentially includes, along the optical axis from the object side to the image side: a refractive lens and a metasurface lens; the refractive lens has a positive optical power, the object side surface of the refractive lens bulges towards the object side, and the image side surface of the refractive lens bulges towards the image side; the metasurface lens has a positive optical power, 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; 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. The optical total length of the far-infrared optical system provided by this 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 metasurface lens, and the metasurface lens includes a substrate and a micro-nano structure. Since the substrate can replace the protective glass, the metasurface lens has the functions of both the metasurface lens itself and the protective glass. Therefore, the far-infrared optical system does not need to use a protective glass, which can reduce the number of optical elements of the far-infrared optical system, and can improve the integration degree of the far-infrared optical system, and can further compress the volume and cost of the far-infrared optical system, making the far-infrared optical system have the advantages of miniaturization and light weight. Description of the Drawings
[0017] By referring to the accompanying drawings and describing its exemplary embodiments in detail, the above and other objectives, features, and advantages of this application will become more apparent.
[0018] Figure 1 Fig. shows a schematic diagram of the architecture layout of the far-infrared optical system in an embodiment of this application.
[0019] Figure 2 Fig. shows the MTF field curve diagram of the far-infrared optical system in an embodiment of this application;
[0020] Figure 3 Fig. shows the field curvature diagram of the far-infrared optical system in an embodiment of this application.
[0021] Figure 4 Fig. shows the distortion diagram of the far-infrared optical system in an embodiment of this application.
[0022] Figure 5 Fig. shows a schematic diagram of the architecture layout of the far-infrared optical system in an embodiment of this application.
[0023] Figure 6 Fig. shows the MTF field curve diagram of the far-infrared optical system in an embodiment of this application;
[0024] Figure 7 Fig. shows the field curvature diagram of the far-infrared optical system in an embodiment of this application.
[0025] Figure 8 Fig. shows the distortion diagram of the far-infrared optical system in an embodiment of this 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 MTF field curve graph of the far-infrared optical system in an embodiment of the present application;
[0028] Figure 11 Shows the field curvature graph of the far-infrared optical system in an embodiment of the present application.
[0029] Figure 12 Shows the distortion graph of the far-infrared optical system in an embodiment of the present application.
[0030] Figure 13 Shows the schematic diagram of the architecture layout of the far-infrared optical system in an embodiment of the present application.
[0031] Figure 14 Shows the MTF field curve graph of the far-infrared optical system in an embodiment of the present application;
[0032] Figure 15 Shows the field curvature graph of the far-infrared optical system in an embodiment of the present application.
[0033] Figure 16 Shows the distortion graph of the far-infrared optical system in an embodiment of the present application.
[0034] Reference numerals
[0035] 100, far-infrared optical system;
[0036] 10, refractive lens;
[0037] 20, metasurface; 210, substrate; 220, micro-nano structure;
[0038] 30, aperture;
[0039] A, object plane; B, image plane; S, optical axis. Detailed implementation manners
[0040] Now, example embodiments will be described more fully with reference to the accompanying drawings. However, the example embodiments can be implemented in various forms and should not be construed as limited to the examples set forth herein; rather, these example embodiments are provided so that the description of the present application will be more complete and thorough, and will fully convey the concept of the example embodiments 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 drawings denote the same or similar parts, and thus their repeated description will be omitted.
[0041] In addition, the described features, structures, or characteristics may 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 one or more of the specific details may be omitted to practice the technical solutions of the present application, or other modules, components, etc. may be used. In other cases, well-known structures, methods, implementations, or operations are not shown or described in detail to avoid obscuring various aspects of the present application.
[0042] Please refer to Figure 1 , Figure 1 which 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 , the object is located on the left side of the leftmost lens, that is, the object side is on the left side of the leftmost lens, and the object surface A is 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 on the right side of the rightmost lens, and the image surface B is on the image side. Therefore, the direction from the object surface A to the image surface B along the optical axis S is consistent with the direction from the object side to the image side along the optical axis S.
[0043] For each optical element of the far-infrared optical system 100, the side close to the object side is the object side of the corresponding optical element, and the side 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. For each optical element of the far-infrared optical system 100, the surface close to the object side is the object side surface of the corresponding optical element, and the surface 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.
[0044] The far-infrared optical system 100 includes a refractive lens 10 and a metasurface lens 20, and the refractive lens 10 and the metasurface lens 20 are arranged in sequence along the direction of the optical axis S from the object side to the image side.
[0045] The refractive power of the refractive lens 10 is positive. The object side surface of the refractive lens 10 bulges towards the object side, and the image side surface of the refractive lens 10 bulges towards the image side.
[0046] The refractive power of the metasurface lens 20 is positive. The metasurface lens 20 includes a substrate 210 and a micro-nano structure 220. The micro-nano structure 220 is provided on the object side surface and / or the image side surface of the substrate 210, and the filling material between the micro-nano structures 220 is air or other materials that are transparent in the working wavelength band. 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 metasurface lens 20 can achieve the corresponding optical performance.
[0047] The far-infrared optical system 100 satisfies Conditional Equation 1: 0.02 mm ≤ L ≤ 1 mm, where L is the distance between the image side of the metalens 20 and the image plane B of the far-infrared optical system 100. Since the imaging detector matched with the far-infrared optical system 100 is arranged on the image plane B, when the far-infrared optical system 100 satisfies Conditional Equation 1, the substrate 210 is located on the object side of the imaging detector, and the substrate 210 is relatively close to the imaging detector. The substrate 210 can be used as a protective glass to protect the imaging detector. Since the substrate 210 can replace the protective glass and reduces the number of optical elements, the far-infrared optical system 100 has the advantages of high integration and small volume, making the far-infrared optical system 100 have the advantages of miniaturization and light weight.
[0048] 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 functions as a protective glass. Since there is no need to additionally set 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.
[0049] 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. The metalens 20 includes a substrate 210 and a micro-nano structure 220. Since the substrate 210 can replace the protective glass, the metalens 20 simultaneously has the functions of the metalens 20 itself and the protective glass. Therefore, the far-infrared optical system 100 does not need to use a protective glass, which can reduce the number of optical elements of the far-infrared optical system 100, and can improve the integration of the far-infrared optical system 100, and can further compress the volume and cost of the far-infrared optical system 100, making the far-infrared optical system 100 have the advantages of miniaturization and light weight.
[0050] In some embodiments, the far-infrared optical system 100 satisfies Conditional Equation 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 small, the distance between the metalens 20 and the imaging detector is relatively close, and the metalens 20 is likely to collide with the imaging detector during assembly, resulting in difficult installation. 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.
[0051] Further, in some embodiments, L = 0.05 mm, so that the far-infrared optical system 100 takes into account both the advantages of a relatively short overall optical length and relatively low installation difficulty.
[0052] In some embodiments, the micro-nano structure 220 is disposed on the object side of the substrate 210.
[0053] In some embodiments, the micro-nano structure 220 is disposed on the image side of the substrate 210.
[0054] 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.
[0055] In some embodiments, the micro-nano structure 220 is a positive micro-nano structure.
[0056] In some embodiments, the micro-nano structure 220 is a negative micro-nano structure.
[0057] In some embodiments, the micro-nano structure 220 has one layer, so that the processing technology of the metalens 20 is compatible with the existing semiconductor processing technology, which is convenient for the processing and manufacturing of the metalens 20.
[0058] 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.
[0059] 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 the expected performance.
[0060] In some embodiments, the phase distribution of the metalens 20 satisfies the following formula:
[0061]
[0062]
[0063] 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, and f m is the focal length of the metalens 20.
[0064] In some embodiments, the refractive lens 10 is an aspherical lens, such that the far-infrared optical system 100 has excellent performance in aberration control, and can further improve the imaging quality of the far-infrared optical system 100.
[0065] 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.
[0066] In some embodiments, the material of the refractive lens 10 is chalcogenide glass, such that the refractive lens 10 can be 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.
[0067] In some embodiments, the material of the refractive lens 10 is silicon. Since lenses made of silicon have low cost, when the material of the refractive lens 10 is silicon, the production cost of the far-infrared optical system 100 can be further reduced.
[0068] In some embodiments, the material of the refractive lens 10 is germanium. Since germanium has a 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.
[0069] In some embodiments, the far-infrared optical system 100 satisfies Conditional Equation Three: where f g is the focal length of the refractive lens 10, and f m is the focal length of the meta-lens 20. The dimensions of f g , f m are the same, both being length units, such as millimeters.
[0070] The upper limit of Conditional Equation Three is used to ensure that the refractive lens 10 bears the main optical power in the far-infrared optical system 100 to effectively focus the light beam. The lower limit of Conditional Equation Three is used to ensure that the meta-lens 20 has a reasonable optical power, which helps to correct aberrations.
[0071] In some embodiments, the far-infrared optical system 100 satisfies Conditional Equation Four: where R g1 is the radius of curvature of the object side of the refractive lens 10, R g2 is the radius of curvature of the image side of the refractive lens 10, and f is the effective focal length of the far-infrared optical system 100. The dimensions of R g1 , R g2 , and f are the same, all being length units, such as millimeters.
[0072] The upper limit of Conditional Formula Four can ensure that the object side of the refractive lens 10 has a relatively large radius of curvature, thereby reducing the incident angle of the light beam on the object side of the refractive lens 10 to reduce aberration. At the same time, the upper limit of Conditional Formula Four can ensure that the light beam can be effectively focused after passing through the image side of the refractive lens 10. The lower limit of Conditional Formula Four is used to control the curvature of the refractive lens 10, thereby controlling field curvature and aberration, and the lower limit of Conditional Formula Four can ensure that the refractive lens 10 has good processability.
[0073] In some embodiments, the far-infrared optical system 100 satisfies Conditional Formula Five: where CT g is the central thickness of the refractive lens 10, that is, CT g is the thickness of the refractive lens 10 on the optical axis S, and the dimension of CT g is a length unit, such as millimeters. n is the refractive index of the refractive lens 10, and c g1 is the curvature of the object side of the refractive lens 10, and c g2 is the curvature of the image side of the refractive lens 10. The dimensions of c g1 and c g2 are the same, both being the negative first power of a length unit, such as mm -1 .
[0074] The upper limit of Conditional Formula Five can prevent the central thickness of the refractive lens 10 from being too large. If the central thickness of the refractive lens 10 is too large, it will result in a higher cost. At the same time, the upper limit of Conditional Formula Five also ensures that the refractive lens 10 can bear sufficient optical power to effectively focus the light beam. The lower limit of Conditional Formula Five can prevent the central thickness of the refractive lens 10 from being too small. If the central thickness of the refractive lens 10 is too small, it will be difficult to process.
[0075] In some embodiments, the far-infrared optical system 100 satisfies Conditional Formula Six: where 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. The dimensions of f and EPD are the same, both being length units, such as millimeters.
[0076] Conditional Formula Six reflects the range of the F-number of the far-infrared optical system 100. From Conditional Formula Six, it can be seen that the F-number of the far-infrared optical system 100 is relatively small, which can greatly increase the light input of the far-infrared optical system 100 and collect as much energy as possible entering the far-infrared optical system 100, thereby ensuring excellent imaging quality.
[0077] 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.
[0078] Further, in some embodiments, the aperture 30 is disposed on the object side of the refractive lens 10. Specifically, the position of the aperture 30 satisfies any one of the following conditions:
[0079] (1) Refer to Figure 1 、 Figure 5 、 Figure 9 and Figure 13 , the aperture 30 is located on the object side of the refractive lens 10, and the aperture 30 is spaced apart from the refractive lens 10;
[0080] (2) The aperture 30 is located on the object side of the refractive lens 10, and the aperture 30 is disposed in contact with the object side surface of the refractive lens 10;
[0081] Further, in some embodiments, the aperture 30 is disposed between any two adjacent lenses. Specifically, the position of the aperture 30 satisfies any one of the following conditions:
[0082] (1) The aperture 30 is located between the refractive lens 10 and the metalens 20, and the aperture 30 is disposed in contact with the image side surface of the refractive lens 10;
[0083] (2) The aperture 30 is located between the refractive lens 10 and the metalens 20, and the aperture 30 is spaced apart from both the refractive lens 10 and the metalens 20;
[0084] (3) The aperture 30 is located between the refractive lens 10 and the metalens 20, and the aperture 30 is disposed in contact with the object side surface of the metalens 20.
[0085] In some embodiments, the aperture 30 is disposed on the object side of the refractive lens 10, and the aperture 30 is spaced apart from the refractive lens 10. The far-infrared optical system 100 satisfies Condition VII: where L a2 is the distance between the image side surface of the refractive lens 10 and the object side surface of the metalens 20 on the optical axis S, L a3 is the distance between the image side surface of the metalens 20 and the image plane B of the far-infrared optical system 100. TTL (Total Track Length, abbreviated as TTL) is the total optical length of the far-infrared optical system 100. L a2 、L a3 、TTL have the same dimension, which is a length unit, such as millimeters.
[0086] The upper limit of Condition VII can avoid an excessive air gap between the refractive lens 10 and the image plane B. If the air gap is too large, it will cause the volume of the optical system to be too large, and it will also cause the volume and weight of the lens corresponding to the optical system to be too large. The lower limit of Condition VII is used to ensure that the far-infrared optical system 100 has an appropriate optical back focal length, which is convenient for the installation of the lens corresponding to the optical system.
[0087] In some embodiments, the aperture 30 is disposed on the object side of the refractive lens 10, and the aperture 30 is spaced apart from the refractive lens 10. The far-infrared optical system 100 satisfies Condition VIII: where n is the refractive index of the refractive lens 10, 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. L a1 is the distance between the aperture 30 and the object side surface of the refractive lens 10 on the optical axis S, R g1 is the radius of curvature of the object side surface of the refractive lens 10, CT g is the central thickness of the refractive lens 10. L a1 、R g1 、CT g have the same dimension, which is a length unit, such as millimeter.
[0088] The upper limit of Condition VIII can ensure that the turning angle of the off-axis beam in the far-infrared optical system 100 is within a reasonable range, and can avoid the increase of aberration of the far-infrared optical system 100 due to too large a turning angle. At the same time, the upper limit of Condition VIII can control the thickness of the refractive lens 10, and can avoid the increase of cost due to too large a volume of the refractive lens 10. The lower limit of Condition VIII can ensure that the refractive lens 10 has an appropriate optical power, so as to effectively focus the beam, and can control the incident angle of the chief ray of the off-axis field of view on the image plane B, so that the far-infrared optical system 100 has a high relative illumination.
[0089] The far-infrared optical system 100 provided by the present application has the following advantages:
[0090] (1) There is no need to use a protective glass. Saving this optical element of the protective glass can reduce the production cost of the far-infrared optical system 100, and can also improve the integration of the far-infrared optical system 100;
[0091] (2) F number ≤ 1.20, which can ensure that the lens has a high light intensity response rate;
[0092] (3) TTL ≤ 3.72 mm, the overall optical length is short, and the volume of the optical system is small;
[0093] (4) The MTF (Modulation Transfer Function, abbreviated as MTF) of the 0.8 field of view at a frequency of 42 lp / mm is above 0.2, and the imaging quality of the far-infrared optical system 100 is better;
[0094] (5) The absolute value of distortion is less than 16%.
[0095] Exemplarily, this application provides four far-infrared optical systems 100 that meet the usage requirements in four embodiments. Next, a detailed introduction to the far-infrared optical systems 100 provided in each embodiment of this application will be given.
[0096] Embodiment 1
[0097] Figure 1 Fig. 7 shows a schematic diagram of the architecture layout of the far-infrared optical system 100 provided in Embodiment 1. Figure 1 The mid- and far-infrared optical system 100 includes, in sequence along the optical axis S from the object surface A to the image surface B: a diaphragm 30, a refractive lens 10, and a metasurface 20. Among them, the refractive lens 10 is a spherical lens, and the micro-nano structure 220 is located on the object side surface of the metasurface 20. Some parameters of the far-infrared optical system 100 provided in Embodiment 1 are shown in Table 1-1.
[0098] Table 1-1. Some parameters of the far-infrared optical system 100 provided in Embodiment 1
[0099] Parameter Data Total Track Length (TTL) 3.71 mm Maximum Field Angle (2ω) 71.3° F - number 1.10 Effective Focal Length 1.26 mm Operating Wavelength Band Long - wave Infrared (8μm - 12μm)
[0100] As can be seen from Table 1-1, the overall optical length of the far-infrared optical system 100 is relatively short, only 3.71 mm. Therefore, the volume of the far-infrared optical system 100 provided in Embodiment 1 is relatively small. The F-number of the far-infrared optical system 100 is 1.10, which can greatly improve the light input 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.
[0101] Along the direction of the optical axis S from the object surface A to the image surface B, starting from the object surface A, 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.
[0102] Table 1-2. Parameters of each surface in the far-infrared optical system 100 provided in Embodiment 1
[0103] Surface Number Surface Type Radius of Curvature (mm) Thickness (mm) Material 0 Object Surface Infinity Infinity - 1 Aperture Infinity 0.50 - 2 Spherical Surface 13.00 1.70 Silicon 3 Spherical Surface -4.16 0.96 - 4 Structural Surface Infinity 0.50 Silicon 5 Spherical Surface Infinity 0.05 - 6 Image Surface Infinity - -
[0104] For each surface in Table 1-2, surface 0 is the object surface A, and surface 1 is the diaphragm 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 metasurface 20, and surface 5 is the image side surface of the metasurface 20. Surface 6 is the image surface B.
[0105] 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 0.50 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 13.00 mm, the distance between Surface 2 and Surface 3 is 1.70 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 -4.16 mm, the distance between Surface 3 and Surface 4 is 0.96 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 0.50 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 0.05 mm, and the material between Surface 5 and Surface 6 is air.
[0106] Please refer to Figure 2 , Figure 2 which shows the MTF field curve graph of the far-infrared optical system 100 provided in Embodiment 1. Figure 2 In Figure 2 , the horizontal axis is the image height, and its unit is millimeter, that is, Figure 2 the horizontal axis in Figure 2 measures the field of view with the image height; Figure 2 The vertical axis in
[0107] Please refer to Figure 3 , Figure 3 which shows the field curvature graph of the far-infrared optical system 100 provided in Embodiment 1. Figure 3 In Figure 3 , the horizontal axis is the field curvature, and its unit is millimeter; Figure 3 the vertical axis in Figure 3It can be known that the maximum field curvature of the far-infrared optical system 100 provided in Embodiment 1 in the sagittal direction under the far-infrared light of 10 microns is 0.049 mm, and the maximum field curvature of the far-infrared optical system 100 provided in Embodiment 1 in the meridional direction under the far-infrared light of 10 microns is 0.077 mm. The field curvature is small, meeting the requirements for field curvature in the excellent imaging quality standard.
[0108] Please refer to Figure 4 , Figure 4 which shows the distortion diagram of the far-infrared optical system 100 provided in Embodiment 1. Figure 4 In Figure 4 , the horizontal axis is distortion, and its unit is percentage; Figure 4 In Figure 4 , the distortion curves M1, M2, and M3 of the far-infrared optical system 100 provided in Embodiment 1 under the far-infrared light with wavelengths of 8 microns, 10 microns, and 12 microns are respectively shown. It can be known from
[0109] Embodiment 2
[0110] Figure 5 which shows the schematic diagram of the architecture layout of the far-infrared optical system 100 provided in Embodiment 2. Figure 5 In the far-infrared optical system 100, along the optical axis S from the object surface A to the image surface B, it successively includes: a diaphragm 30, a refractive lens 10, and a metasurface lens 20. Among them, the refractive lens 10 is a spherical lens, and the micro-nano structure 220 is located on the object side surface of the metasurface lens 20. Some parameters of the far-infrared optical system 100 provided in Embodiment 2 are shown in Table 2-1.
[0111] Table 2-1. Some parameters of the far-infrared optical system 100 provided in Embodiment 2
[0112] Parameter Data Total Track Length (TTL) 3.55 mm Maximum Field Angle (2ω) 71.1° F - number 1.13 Effective Focal Length 1.30 mm Operating Wavelength Band Long - wave Infrared (8μm - 12μm)
[0113] It can be known from Table 2-1 that the overall optical length of the far-infrared optical system 100 is relatively short, only 3.55 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 1.13, which can greatly improve the light input of the far-infrared optical system 100 and collect as much energy entering the far-infrared optical system 100 as possible under the condition that the imaging detector has a low response to light energy, thereby ensuring excellent imaging quality.
[0114] Along the direction of the optical axis S from the object surface A to the image surface B, starting from the object surface A, 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.
[0115] Table 2-2. Parameters of Each Surface in the Far-Infrared Optical System 100 Provided in Embodiment 2
[0116] Surface Number Surface Type Radius of Curvature (mm) Thickness (mm) Material 0 Object Surface Infinity Infinity - 1 Aperture Infinity 0.59 - 2 Spherical Surface 16.21 1.40 Silicon 3 Spherical Surface -4.07 1.01 - 4 Structural Surface Infinity 0.50 Silicon 5 Spherical Surface Infinity 0.05 - 6 Image Surface Infinity - -
[0117] For the analysis of each surface in Table 2-2, reference can be made to Embodiment 1, and this embodiment will not be analyzed in detail here.
[0118] Please refer to Figure 6 , Figure 6 which shows the MTF field curve graph of the far-infrared optical system 100 provided in Embodiment 2. Figure 6 The horizontal axis in Figure 6 is the image height, and its unit is millimeter, that is, Figure 6 the horizontal axis in Figure 6 measures the field of view with the image height; Figure 6 The vertical axis in
[0119] Please refer to Figure 7 , Figure 7 which shows the field curvature graph of the far-infrared optical system 100 provided in Embodiment 2. Figure 7 The horizontal axis in Figure 7 is the field curvature, and its unit is millimeter; Figure 7 The vertical axis in Figure 7 is the Y-axis field of view, and its unit is degree. Among them,
[0120] Please refer to Figure 8 , Figure 8 which shows the distortion graph of the far-infrared optical system 100 provided in Embodiment 2.Figure 8 The horizontal axis in it is distortion, and its unit is percentage; Figure 8 The vertical axis in it is the Y-axis field of view, and its unit is degree. Figure 8 The distortion curves M1, M2, and M3 of the far-infrared optical system 100 provided in Example 2 under far-infrared light with wavelengths of 8 μm, 10 μm, and 12 μm are respectively shown in it. From Figure 8 it can be seen that the maximum distortion of the far-infrared optical system 100 provided in Example 2 is -14%.
[0121] Example 3
[0122] Figure 9 The schematic diagram of the architecture layout of the far-infrared optical system 100 provided in Example 3 is shown. Figure 9 In the far-infrared optical system 100, along the optical axis S from the object surface A to the image surface B, it successively includes: a diaphragm 30, a refractive lens 10, and a super lens 20. Among them, the refractive lens 10 is a spherical lens, and the micro-nano structure 220 is located on the object side surface of the super lens 20. Some parameters of the far-infrared optical system 100 provided in Example 3 are shown in Table 3-1.
[0123] Table 3-1. Some parameters of the far-infrared optical system 100 provided in Example 3
[0124] Parameter Data Total Track Length (TTL) 3.67 mm Maximum Field Angle (2ω) 72.6° F - number 1.11 Effective Focal Length 1.28 mm Operating Wavelength Band Long - wave Infrared (8μm - 12μm)
[0125] It can be seen from Table 2-1 that the overall optical length of the far-infrared optical system 100 is relatively short, only 3.67 mm. Therefore, the volume of the far-infrared optical system 100 provided in Example 3 is relatively small. The F number of the far-infrared optical system 100 is 1.11, which can greatly improve the light input of the far-infrared optical system 100 and 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.
[0126] Along the direction of the optical axis S from the object surface A to the image surface B, starting from the object surface A, 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.
[0127] Table 2-2. Parameters of each surface in the far-infrared optical system 100 provided in Example 3
[0128] Surface Number Surface Type Radius of Curvature (mm) Thickness (mm) Material 0 Object Surface Infinity Infinity - 1 Aperture Infinity 0.35 - 2 Spherical Surface 65.27 1.74 Silicon 3 Spherical Surface -3.46 1.03 - 4 Structural Surface Infinity 0.50 Silicon 5 Spherical Surface Infinity 0.05 - 6 Image Surface Infinity - -
[0129] For the analysis of each surface in Table 3-2, reference can be made to Example 1, and this example will not be analyzed in detail.
[0130] Please refer to Figure 10 , Figure 10Shows the MTF field curve graph of the far-infrared optical system 100 provided in Embodiment 3, Figure 10 where the horizontal axis in Figure 10 is the image height, and its unit is millimeter, that is, Figure 10 the horizontal axis in Figure 10 measures the field of view with the image height; Figure 10 the vertical axis in
[0131] Please refer to Figure 11 and Figure 11 shows the field curvature graph of the far-infrared optical system 100 provided in Embodiment 3, Figure 11 where the horizontal axis in Figure 11 is the field curvature, and its unit is millimeter; Figure 11 the vertical axis in Figure 11 is the Y-axis field of view, and its unit is degree. Among them,
[0132] Please refer to Figure 12 and Figure 12 shows the distortion graph of the far-infrared optical system 100 provided in Embodiment 3, Figure 12 where the horizontal axis in Figure 12 is the distortion, and its unit is percentage; Figure 12 the vertical axis in Figure 12 is the Y-axis field of view, and its unit is degree. Figure 12 respectively shows the distortion curves M1, M2, and M3 of the far-infrared optical system 100 provided in Embodiment 3 under far-infrared light with wavelengths of 8 microns, 10 microns, and 12 microns. From Figure 12 it can be known that the maximum distortion of the far-infrared optical system 100 provided in Embodiment 3 is -14%.
[0133] Example 4
[0134] Figure 13 Fig. 5 shows a schematic diagram of the architecture layout of the far-infrared optical system 100 provided in Example 4. Figure 13 The mid- and far-infrared optical system 100 sequentially includes, along the optical axis S from the object plane A to the image plane B: a diaphragm 30, a refractive lens 10, and a metasurface lens 20. Among them, the refractive lens 10 is a spherical lens, and the micro-nano structure 220 is located on the object side surface of the metasurface lens 20. Some parameters of the far-infrared optical system 100 provided in Example 4 are shown in Table 4-1.
[0135] Table 4-1. Some parameters of the far-infrared optical system 100 provided in Example 4
[0136] Parameter Data Total Track Length (TTL) 3.63 mm Maximum Field Angle (2ω) 71.6° F - number 1.20 Effective Focal Length 1.38 mm Operating Wavelength Band Long - wave Infrared (8μm - 12μm)
[0137] As can be seen from Table 4-1, the overall optical length of the far-infrared optical system 100 is relatively short, only 3.63 mm. Therefore, the volume of the far-infrared optical system 100 provided in Example 4 is relatively small. The F-number of the far-infrared optical system 100 is 1.20, which can greatly increase the light input of the far-infrared optical system 100 and 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.
[0138] Along the direction of the optical axis S from the object plane A to the image plane B, starting from the object plane A, each surface in the far-infrared optical system 100 is numbered, and after summarizing the parameters of each surface, the following Table 4-2 is obtained.
[0139] Table 4-2. Parameters of each surface in the far-infrared optical system 100 provided in Example 4
[0140]
[0141]
[0142] For the analysis of each surface in Table 4-2, reference can be made to Example 1, and this example will not be analyzed in detail.
[0143] Please refer to Figure 14 , Figure 14 Fig. 8 shows the MTF field-of-view curve graph of the far-infrared optical system 100 provided in Example 4. Figure 14 The horizontal axis in Fig. 8 is the image height, and its unit is mm, that is, Figure 14 the horizontal axis in Fig. 8 measures the field of view with the image height; Figure 14 the vertical axis in Fig. 8 is the MTF value. Figure 14The sagittal curve S3 and meridional curve T3 of the MTF varying with the field of view at a spatial frequency of 10 lp / mm are listed, the sagittal curve S2 and meridional curve T2 of the MTF varying with the field of view at a spatial frequency of 21 lp / mm, and the sagittal curve S1 and meridional curve T1 of the MTF varying with the field of view at a spatial frequency of 42 lp / mm. From Figure 14 it can be seen that within the field of view of 0.8 (image height of 0.6512 mm), the MTF is greater than 0.21, and the imaging quality of the far-infrared optical system 100 is relatively good.
[0144] Please refer to Figure 15 , Figure 15 which shows the field curvature diagram of the far-infrared optical system 100 provided in Embodiment 4. Figure 15 In it, the horizontal axis is the field curvature, and its unit is millimeter; Figure 15 the vertical axis is the Y-axis field of view, and its unit is degree. Among them, Figure 15 shows the field curvature T1 in the meridional direction of the far-infrared light with a wavelength of 8 μm; the field curvature T2 in the meridional direction of the far-infrared light with a wavelength of 10 μm; the field curvature T3 in the meridional direction of the far-infrared light with a wavelength of 12 μm. Since the field curvature curves of the far-infrared light with wavelengths of 8 μm, 10 μm, and 12 μm in the sagittal direction almost overlap, therefore, in this embodiment, they are not distinguished and are uniformly marked as S. From Figure 15 it can be seen that the maximum field curvature of the far-infrared optical system 100 provided in Embodiment 4 in the sagittal direction under the far-infrared light of 10 μm is 0.082 mm, and the maximum field curvature of the far-infrared optical system 100 provided in Embodiment 1 in the meridional direction under the far-infrared light of 10 μm is 0.079 mm. The field curvature is small and meets the requirements for the field curvature in the excellent imaging quality standard.
[0145] Please refer to Figure 16 , Figure 16 which shows the distortion diagram of the far-infrared optical system 100 provided in Embodiment 4. Figure 16 In it, the horizontal axis is the distortion, and its unit is percentage; Figure 16 the vertical axis is the Y-axis field of view, and its unit is degree. Figure 16 shows the distortion curves of the far-infrared optical system 100 provided in Embodiment 4 under the far-infrared light with wavelengths of 8 μm, 10 μm, and 12 μm respectively. Since the three curves almost completely overlap, therefore, in this embodiment, they are not distinguished. From Figure 16 it can be seen that the maximum distortion of the far-infrared optical system 100 provided in Embodiment 4 is -15.6%.
[0146] After summarizing the various parameters of the far-infrared optical system 100 provided in the above 4 embodiments, Table 5 as shown below is obtained. The display of Table 5 is mainly used to illustrate that the various conditions satisfied by the far-infrared optical system 100 provided in this application are all experimentally verified and supported.
[0147] Table 5. Parameters of the far-infrared optical system 100 provided in each embodiment
[0148]
[0149] This application also provides a far-infrared optical lens. The far-infrared optical lens includes an imaging detector (not shown in the figure) and the above-mentioned far-infrared optical system 100. The architecture of the far-infrared optical system 100 can be referred to above 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).
[0150] Those skilled in the art will readily conceive of other embodiments of this application after considering the specification and practicing the utility model disclosed herein. This application is intended to cover any variations, uses, or adaptations of this application, which follow the general principles of this application and include known common knowledge or conventional technical means in the technical field not disclosed in this application. The specification and examples are only regarded as exemplary, and the true scope and spirit of this 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 refractive lens has a positive focal power, the object side surface of the refractive lens is convex to the object side, and the image side surface of the refractive lens is convex to the image side; the super lens has a 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 of the substrate 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: Among them, the f g is the focal length of the refractive lens, the f m is the focal length of the metalens.
4. 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 R g1 is the radius of curvature of the object side of the refractive lens, and the R g2 is the curvature radius of the image side surface of the refractive lens, and f is the effective focal 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: Among them, the CT g is the center thickness of the refractive lens, n is the refractive index of the refractive lens, and c g1 is the curvature of the object side of the refractive lens, and c g2 is the curvature of the image-side surface of the refractive lens.
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, 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.
7. 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.
8. The far-infrared optical system according to claim 7, characterized in that: The aperture is arranged on the object side of the refractive lens, and the far-infrared optical system satisfies: Among them, the L a2 is the distance between the image side of the refractive lens and the object side of the super lens on the optical axis, and L a3 is the distance between the image side surface of the superlens and the image plane of the far-infrared optical system, and the TTL is the total optical length of the far-infrared optical system.
9. The far-infrared optical system according to claim 7, characterized in that: The aperture is arranged on the object side of the refractive lens, and the far-infrared optical system satisfies: Wherein, n is the refractive index of the refractive lens, FOV is the maximum field of view of the far-infrared optical system, and L a1 is the distance between the aperture and the object side of the refractive lens on the optical axis, and R g1 is the radius of curvature of the object side of the refractive lens, the CT g is the center thickness of the refractive 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.