Far infrared optical system and far infrared optical lens

Abstract

The utility model discloses a far infrared optical system and a far infrared optical lens, the far infrared optical system comprises a super lens, the focal power of the super lens is positive, and the super lens comprises a substrate and a micro-nano structure; at least one of the object side surface and the image side surface of the substrate is provided with a micro-nano structure. The far infrared optical system meets the condition that delta phi m is larger than or equal to 4D and smaller than or equal to 1000D, delta phi m is the difference value between the maximum focal power and the minimum focal power of the super lens under the working wave band, and D is equal to m-1. The total optical length of the far-infrared optical system provided by the utility model is short, so that the size of the far-infrared optical system is small, and miniaturization can be realized. According to the far infrared optical system, only the super-lens is used as the lens for modulating the light, and the production cost of the single super-lens is low when the super-lens is produced in batches, so that the far infrared optical system has the advantage of low cost. Moreover, the super lens is a plane lens, so that the far infrared optical system also has the advantages of being easy to produce, assemble and integrate on a large scale.

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] The far-infrared optical system has good anti-interference performance and can work around the clock. It is widely used in industrial, security, medical and other fields.

[0003] In the prior art, the far-infrared optical system usually has a large number of lenses, which results in a large volume of the far-infrared optical system, making it difficult to install in a small space. In addition, the large number of lenses in the far-infrared optical system also results in high cost and difficulty in assembly. Utility Model Content

[0004] 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, aiming to provide a far-infrared optical system and a far-infrared optical lens that are small in size, low in cost and easy to assemble.

[0005] According to one aspect of an embodiment of the present application, a far-infrared optical system is disclosed, the far-infrared optical system comprising: a superlens, the optical focal power of the superlens is positive, the superlens comprising: a substrate and a micro-nano structure; at least one of the object side surface of the substrate and the image side surface of the substrate is provided with the micro-nano structure;

[0006] The far-infrared optical system satisfies: 4D≤ΔΦ m ≤1000D, where the ΔΦ m is the difference between the maximum optical focal length and the minimum optical focal length of the metalens in the working band, and D=m -1 .

[0007] In some embodiments, the far-infrared optical system satisfies: Among them, the Φ m is the optical power provided by the metalens at the central wavelength, and the T m is the thickness of the superlens.

[0008] In some embodiments, the far-infrared optical system satisfies: The surface of the substrate provided with the micro-nano structure is a structural surface, and the surface with the largest phase value provided by each of the structural surfaces is a first target structural surface. is the maximum phase value provided by the first target structure surface; the r m is the effective area radius of the metalens, and p represents a radian of 2π.

[0009] In some embodiments, the far-infrared optical system satisfies: The surface of the substrate provided with the micro-nano structure is a structural surface, and the surface having the largest difference between the maximum spatial phase gradient and the minimum spatial phase gradient at the central wavelength is a second target structural surface. is the maximum spatial phase gradient provided by the second target structure surface at the central wavelength, It is the minimum spatial phase gradient provided by the second target structure surface at the central wavelength.

[0010] In some embodiments, the far-infrared optical system satisfies: Among them, the TTL is the total optical length of the far-infrared optical system, the ImgH is the imaging area radius of the far-infrared optical system on the image plane corresponding to the maximum half field of view angle, the BFL is the optical back focal length of the far-infrared optical system, and f is the effective focal length of the far-infrared optical system.

[0011] In some embodiments, the far-infrared optical system satisfies: Wherein, ImgH is the imaging area radius of the far-infrared optical system on the image plane corresponding to the maximum half field angle, and E L is the maximum vertical axis chromatic aberration of the far-infrared optical system, and F# is the aperture number of the far-infrared optical system.

[0012] In some embodiments, the far-infrared optical system further includes an aperture, and the aperture and the super lens are sequentially arranged along the optical axis from the object side to the image side.

[0013] In some embodiments, the far-infrared optical system satisfies: The L 1 is the distance between the image side surface of the aperture and the image side surface of the super lens on the optical axis, and the TTL is the total optical length of the far-infrared optical system.

[0014] In some embodiments, the far-infrared optical lens comprises: an imaging detector and a far-infrared optical system as described in any one of the above items, and the imaging detector is arranged on the image plane of the far-infrared optical system.

[0015] A second aspect of an embodiment of the present application provides a far-infrared optical lens, which also includes a lens barrel, the lens barrel is provided with a through hole, the through hole includes a first hole segment, a second hole segment, a third hole segment, and a fourth hole segment connected in sequence, the diameter of the second hole segment is smaller than the diameter of the third hole segment, and the diameter of the third hole segment is smaller than the diameter of the fourth hole segment; the super lens is accommodated in the fourth hole segment.

[0016] The far-infrared optical system provided by the present application includes a metalens, the optical power of the metalens is positive, and the metalens includes: a substrate and a micro-nano structure; at least one of the object side surface and the image side surface of the substrate is provided with a micro-nano structure. The far-infrared optical system satisfies: 4D≤ΔΦ m ≤1000D, where ΔΦ m is the difference between the maximum and minimum focal lengths of the metalens in the working band, D = m -1 . The far-infrared optical system provided by the present application has a short total optical length, so the far-infrared optical system is small in size and can be miniaturized. The only lens in the far-infrared optical system that modulates light is the metalens. When the metalens are mass-produced, the production cost of a single metalens is low, which makes the far-infrared optical system have the advantage of low cost. In addition, the metalens is a flat lens, which makes the far-infrared optical system also have the advantages of easy production and assembly and easy large-scale integration. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] 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.

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

[0019] Figure 2 The MTF field of view curve of the far-infrared optical system in one embodiment of the present application is shown.

[0020] Figure 3 A schematic diagram of the architecture layout of a far-infrared optical system in an embodiment of the present application is shown.

[0021] Figure 4 The MTF field of view curve of the far-infrared optical system in one embodiment of the present application is shown.

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

[0023] Figure 6 The MTF field of view curve of the far-infrared optical system in one embodiment of the present application is shown.

[0024] Figure 7 A schematic diagram of the architecture layout of a far-infrared optical system in an embodiment of the present application is shown.

[0025] Figure 8 The MTF field of view curve of the far-infrared optical system in one embodiment of the present application is shown.

[0026] Fig. 9A schematic diagram of the architecture layout of a far-infrared optical system in an embodiment of the present application is shown.

[0027] Fig.10 The MTF field of view curve of the far-infrared optical system in one embodiment of the present application is shown.

[0028] Fig.11 A schematic diagram of the architecture layout of a far-infrared optical system in an embodiment of the present application is shown.

[0029] Fig.12 The MTF field of view curve of the far-infrared optical system in one embodiment of the present application is shown.

[0030] Fig.13 A schematic diagram of the architecture layout of a far-infrared optical system in an embodiment of the present application is shown.

[0031] Fig.14 The MTF field of view curve of the far-infrared optical system in one embodiment of the present application is shown.

[0032] Fig.15 A schematic diagram of the partial structure of a far-infrared optical lens in an embodiment of the present application is shown.

[0033] Reference numerals

[0034] 100. Far infrared optical system;

[0035] 10. Super lens; 110. Substrate; 120. Micro-nano structure;

[0036] 20. Aperture;

[0037] 30. Protective glass;

[0038] A, object plane; B, image plane; S, optical axis;

[0039] 200, lens barrel; 2001, perforation; 2001a, first hole segment; 2001b, second hole segment; 2001c, third hole segment; 2001d, fourth hole segment;

[0040] 1000. Far infrared optical lens. DETAILED DESCRIPTION

[0041] 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.

[0042] 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.

[0043] 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 far-infrared optical system 100, 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 far-infrared optical system 100, and the image plane B is located on the image side.

[0044] The side of each optical element of the far-infrared optical system 100 close to the object side is the object side of the corresponding optical element, and the side of each optical element of the far-infrared optical system 100 close to the image side is the image side of the corresponding optical element. For example, the side of the diaphragm 20 close to the object side is the object side of the diaphragm 20. The surface of each optical element of the far-infrared optical system 100 close to the object side is the object side surface of the corresponding optical element, and the surface of each optical element of the far-infrared optical system 100 close to the image side is the image side surface of the corresponding optical element. For example, the surface of the diaphragm 20 close to the image side is the image side surface of the diaphragm 20.

[0045] The far-infrared optical system 100 includes a metalens 10, and the optical focal power of the metalens 10 is positive. The metalens 10 includes a substrate 110 and a micro-nano structure 120, and at least one of the object side surface of the substrate 110 and the image side surface of the substrate 110 is provided with the micro-nano structure 120, and the micro-nano structure 120 is a sub-wavelength structure. According to the phase modulation method adopted, the corresponding phase modulation formula can be adaptively used to configure the various parameters of the micro-nano structure 120, so that the metalens 10 has the expected optical performance.

[0046] The far-infrared optical system 100 satisfies the conditional formula 1: 4D≤ΔΦ m ≤1000D, where ΔΦ m is the maximum optical focal length Φ of the metalens 10 in the working band max With minimum focal power Φ min The difference, ΔΦ m =Φ max -Φ min , D is the unit of optical power, D = m -1The conditional expression 1 reflects the chromatic aberration correction capability of the metalens 10 . The lower limit of the conditional expression 1 represents the minimum chromatic aberration correction requirement of the far-infrared optical system 100 for the metalens 10 . The upper limit of the conditional expression 1 represents the maximum chromatic aberration correction capability that the metalens 10 can provide in the far-infrared optical system 100 .

[0047] The far-infrared optical system 100 provided by the present application has a short total optical length, so the far-infrared optical system 100 is small in size and can be miniaturized. The only lens in the far-infrared optical system 100 that modulates light is the metalens 10. When the metalens 10 are mass-produced, the production cost of a single metalens 10 is low, so that the far-infrared optical system 100 has the advantage of low cost. In addition, the metalens 10 is a flat lens, so that the far-infrared optical system 100 also has the advantages of easy production and assembly and easy large-scale integration.

[0048] In some embodiments, the micro-nano structure 120 is disposed on the object-side surface of the substrate 110 .

[0049] In some embodiments, the micro-nano structure 120 is disposed on the image side of the substrate 110 .

[0050] In some embodiments, the image-side surface of the substrate 110 and the object-side surface of the substrate 110 are both provided with a micro-nano structure 120 , so that the metalens 10 has a higher degree of design freedom.

[0051] In some embodiments, the micro-nano structure 120 is a positive micro-nano structure.

[0052] In some embodiments, the micro-nano structure 120 is a negative micro-nano structure.

[0053] In some embodiments, the micro-nano structure 120 is provided with a layer to make the processing technology of the superlens 10 compatible with the existing semiconductor processing technology, which can facilitate the processing and manufacturing of the superlens 10.

[0054] In some embodiments, the micro-nano structure 120 has two or more layers, so that the superlens 10 has a larger and expected optical focal length.

[0055] For the superlens 10, the position of the micro-nano structure 120, the positive and negative positions of the micro-nano structure 120, and the number of layers of the micro-nano structure 120 can be freely combined as long as the superlens 10 has the expected performance.

[0056] In some embodiments, the phase distribution of the metalens 10 satisfies the following formula:

[0057]

[0058] Wherein, r is the distance from the center of the superlens 10 to any micro-nanostructure 120, λ is the central wavelength of the working band of the superlens 10, is the phase constant, (x, y) is the two-dimensional coordinate of the surface of the metalens 10, a i , b i 、a ij , b ij are all real coefficients, N is the number of phase coefficients, f m is the focal length of the metalens 10. Since the only optical element capable of modulating light in the far-infrared optical system 100 provided in the present application is the metalens 10, the focal length f of the metalens 10 is m That is the effective focal length f of the far-infrared optical system 100.

[0059] Furthermore, in some embodiments, the far-infrared optical system 100 satisfies the conditional equation 2: 4.7D≤ΔΦ m ≤910D, where ΔΦ m is the difference between the maximum optical power and the minimum optical power of the metalens 10 in the working band, D is the unit of optical power, D=m -1 Conditional formula 2 reflects the chromatic aberration correction capability of the metalens 10. When the metalens 10 satisfies conditional formula 2, the metalens 10 can have a suitable optical focal length and good chromatic aberration correction capability, thereby improving the imaging quality of the far-infrared optical system 100.

[0060] In some embodiments, the far-infrared optical system 100 satisfies conditional formula 3: Among them, Φ m is the optical focal length provided by the metalens 10 at the central wavelength, D is the unit of optical focal length, D=m -1 . T m is the thickness of the superlens 10, T m The dimension of is a unit of length, such as millimeters.

[0061] Conditional formula 3 reflects the optical focal length provided by the super lens 10 unit thickness. The lower limit of conditional formula 3 represents the minimum optical focal length provided by the super lens 10 unit thickness, and the upper limit of conditional formula 3 represents the maximum optical focal length provided by the super lens 10 unit thickness in the far-infrared optical system 100.

[0062] In some embodiments, the far-infrared optical system 100 satisfies Condition 4: The surface of the substrate 110 provided with the micro-nano structure 120 is a structural surface, and the surface with the largest phase value provided by each structural surface is a first target structural surface. is the maximum phase value provided by the first target structural surface. Exemplarily, when the metalens 10 has only one structural surface, the target is the first target structural surface. is the phase value provided by the structural surface; when the metalens 10 has two structural surfaces, the maximum phase value provided by the structural surface located on the object side of the metalens 10 is A 2πrad, and the maximum phase value provided by the structural surface located on the object side of the metalens 10 is B 2πrad. If A>B, the structural surface located on the object side of the metalens 10 is the first target structural surface, and r m is the effective area radius of the superlens 10. The effective area of ​​the superlens 10 refers to the maximum light transmission area of ​​the superlens 10. m The dimension of is a unit of length, such as millimeters. p represents one radian of 2π.

[0063] Conditional formula 4 reflects the ratio of the maximum phase value of the metalens 10 to the effective area radius of the metalens 10, and conditional formula 4 represents the spatial phase provided by the unit effective area radius of the metalens 10. The upper limit of conditional formula 4 represents the maximum spatial phase per unit radius that the metalens 10 can provide, and the lower limit of conditional formula 4 represents the minimum spatial phase per unit radius that the metalens 10 needs to provide in order to achieve the target optical performance and compress the volume in the far-infrared optical system 100.

[0064] In some embodiments, the far-infrared optical system 100 satisfies Condition 5: The surface of the substrate 110 provided with the micro-nano structure 120 is a structural surface, and the surface having the largest difference between the maximum spatial phase gradient and the minimum spatial phase gradient at the central wavelength is a second target structural surface. is the maximum spatial phase gradient provided by the second target structural surface at the central wavelength. Exemplarily, when the metalens 10 has only one structural surface, the target is the second target structural surface. is the maximum spatial phase gradient provided by the structural surface at the central wavelength, is the minimum spatial phase gradient provided by the structural surface at the central wavelength; when the superlens 10 has two structural surfaces, the maximum spatial phase gradient provided by the structural surface located on the object side of the superlens 10 is C 1 2πrad / mm, the minimum spatial phase gradient provided by the structural surface located on the object side of the superlens 10 is C 2 2πrad / mm, the maximum spatial phase gradient provided by the structural surface located on the image side of the superlens 10 is D 1 2πrad / mm, the minimum spatial phase gradient provided by the structural surface located on the image side of the superlens 10 is D 2 2πrad / mm, if C 1 -C 2 >D 1 -D 2 , then the structural surface located on the object side of the super lens 10 is the second target structural surface, and

[0065] Conditional formula 5 represents the focusing capability range that the metalens 10 can provide, because the spatial phase gradient determines the light beam deflection capability of the metalens 10. The upper limit of conditional formula 5 represents the maximum focusing range provided by the metalens 10, and the lower limit of conditional formula 5 represents the minimum focusing range provided by the metalens 10.

[0066] In some embodiments, the far-infrared optical system 100 satisfies conditional formula 6: TTL (Total Track Length, TTL for short) is the total optical length of the far-infrared optical system 100, ImgH is the imaging area radius of the far-infrared optical system 100 corresponding to the maximum half field angle on the image plane B, BFL (Backfocal length, BFL for short) is the optical back focal length of the far-infrared optical system 100, and f is the effective focal length of the far-infrared optical system 100. TTL, ImgH, BFL, and f have the same dimension, which is a length unit, such as millimeters.

[0067] In conditional expression six, The value of is positively correlated with the field of view of the far-infrared optical system 100. The value of is positively correlated with the volume compression of the far-infrared optical system 100, and conditional formula 6 reflects the volume compression degree of the far-infrared optical system 100 within a specific field of view. The upper limit of conditional formula 6 reflects the minimum volume compression degree of the far-infrared optical system 100 within a specific field of view, and the lower limit of conditional formula 6 reflects the maximum volume compression degree of the far-infrared optical system 100 within a specific field of view.

[0068] In some embodiments, the far-infrared optical system 100 satisfies conditional equation 7: Wherein, ImgH is the imaging area radius of the far-infrared optical system 100 on the image plane B corresponding to the maximum half-viewing angle, E L is the maximum vertical axis chromatic aberration of the far-infrared optical system 100, F# is the aperture number of the far-infrared optical system 100, and F# is also the F number. L have the same dimension, which is a unit of length, such as millimeter.

[0069] For the same far-infrared optical system 100, the higher the image height and the smaller the F# and vertical axis chromatic aberration, the more the light beam control capability of the far-infrared optical system 100 is tested. The upper limit of conditional expression 7 represents the maximum light beam control capability of the metalens 10, and the lower limit of conditional expression 7 represents the minimum light beam control capability of the metalens 10.

[0070] See also Figure 1 , Figure 3 , Figure 5 , Figure 7 , Fig. 9 , Fig.11 and Fig.13 In some embodiments, the far-infrared optical system 100 further includes an aperture 20, which is used to control 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.

[0071] The aperture 20 is disposed on the object side of the super lens 10, specifically:

[0072] (1) The aperture 20 is located on the object side of the super lens 10, and the aperture 20 is spaced apart from the super lens 10;

[0073] (2) The aperture 20 is disposed on the object side of the superlens 10 , that is, the aperture 20 is disposed in contact with the surface of the superlens 10 close to the object side.

[0074] In some embodiments, the aperture 20 is located on the object side of the superlens 10, and the aperture 20 is spaced apart from the superlens 10, and the far-infrared optical system 100 satisfies conditional formula eight: L 1 L is the distance between the image side surface of the aperture 20 and the image side surface of the super lens 10 on the optical axis S, and TTL is the total optical length of the far-infrared optical system 100. 1 , TTL have the same dimension, both are length units, such as millimeters.

[0075] In the far-infrared optical system 100, L 1 The length L is the length of the main part of the lens corresponding to the far-infrared optical system 100, 1 The length of directly affects the mechanical length of the lens corresponding to the far-infrared optical system 100. The upper limit of conditional formula eight represents the minimum proportion of the main part of the lens corresponding to the far-infrared optical system 100 in the optical path, that is, the limit of the length compression of the main part of the lens corresponding to the far-infrared optical system 100. The upper limit of conditional formula eight represents the maximum proportion of the main part of the lens corresponding to the infrared optical system in the optical path.

[0076] See also Figure 1 , Figure 3 , Figure 5 and Figure 7 In some embodiments, the far-infrared optical system 100 further includes a protective glass 30 , which is located on the object side of the superlens 10 , and is used to protect an imaging detector matched with the far-infrared optical system 100 .

[0077] See also Fig. 9 , Fig.11 and Fig.13In some embodiments, the far-infrared optical system 100 does not include a protective glass. Along the incident direction of the light, the metalens 10 is located in front of an imaging detector that matches the far-infrared optical system 100 to protect the imaging detector. That is, the metalens 10 in this embodiment has the functions of imaging and protecting the imaging detector. In addition, when the far-infrared optical system 100 does not include a protective glass, it is beneficial to package the metalens 10 and the image detector.

[0078] The maximum working bandwidth of the far-infrared optical system 100 provided in the present application is 8μm-14μm. It can be understood that the actual working band of the far-infrared optical system 100 can be any sub-interval of 8μm-14μm, for example, 8μm-10μm, 8μm-11μm, 10μm-12μm, etc. In addition, since the actual working band of the far-infrared optical system 100 is not fixed, the central wavelength of the working band of the far-infrared optical system 100 is not limited to 10μm, and the central wavelength of the working band of the far-infrared optical system 100 depends on its specific working band.

[0079] The far-infrared optical system 100 provided by the present application has the following benefits:

[0080] (1) Total optical length ≤ 1.64 mm;

[0081] (2) F number ≤ 1.4;

[0082] (3) The superlens 10 is a monolithic flat lens, which is conducive to integrated packaging.

[0083] (4) At a spatial frequency of 14lp / mm, the MTF (Modulation Transfer Function) is greater than 0.34 within a 0.8 field of view.

[0084] (5) The monolithic metalens 10 can achieve wide spectrum imaging in the far-infrared band.

[0085] The present application exemplarily provides 7 far-infrared optical systems 100 that meet usage requirements in 7 embodiments. Next, the far-infrared optical systems 100 provided by the various embodiments of the present application are introduced in detail.

[0086] Example 1

[0087] 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-to-far infrared optical system 100 includes, in order from the object plane A to the image plane B along the optical axis S: an aperture 20, a super lens 10, and a protective glass 30, wherein the aperture 20 is disposed on the object side of the super lens 10. Some parameters of the far-infrared optical system 100 provided in Example 1 are shown in Table 1-1.

[0088] Table 1-1. Partial parameters of the far-infrared optical system 100 provided in Example 1

[0089] parameter data Total optical length (TTL) 1.64mm Maximum field of view (2ω) 146° F-number 1 Effective focal length 0.64mm Working band 8μm-12μm

[0090] As can be seen from Table 1-1, the working band of the far-infrared optical system 100 is 8 microns to 12 microns, and the central wavelength is 10 microns. The total optical length of the far-infrared optical system 100 is relatively short, only 1.64 mm, so the volume of the far-infrared optical system 100 provided in Example 1 is relatively small. The F number of the far-infrared optical system 100 is 1, which can greatly increase the amount of light entering the far-infrared optical system 100, and when the image sensor has a low response to light energy, the energy entering the far-infrared optical system 100 is collected as much as possible, thereby ensuring excellent imaging quality.

[0091] Along the optical axis S from the object plane A to the image plane B, starting from the aperture 20, each surface in the far-infrared optical system 100 is numbered, and the parameters of each surface are summarized to obtain the following Table 1-2.

[0092] Table 1-2. Parameters of various surfaces in the far-infrared optical system 100 provided in Example 1

[0093]

[0094]

[0095] For each surface in Table 1-2, surface 1 is the aperture 20, surface 2 is the object side of the metalens 10, and surface 3 is the image side of the metalens 10. Since the micro-nano structure 120 is provided on surface 3, surface 3 is recorded as the structural surface. Surface 4 is the object side of the protective glass 30, and surface 5 is the image side of the protective glass 30. Surface 6 is the image surface B.

[0096] 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 0.37 mm, and the material between surface 1 and surface 2 is air. Surface 2 is a spherical surface, and its radius of curvature is infinite, that is, surface 2 is a plane, the distance between surface 2 and surface 3 is 0.30 mm, and the material between surface 2 and surface 3 is silicon. Surface 3 is a spherical surface, and its radius of curvature is infinite, that is, surface 3 is a plane, the distance between surface 3 and surface 4 is 0.24 mm, and the material between surface 3 and surface 4 is air. Surface 4 is a spherical surface, and its radius of curvature is infinite, that is, surface 4 is a plane, the distance between surface 4 and surface 5 is 0.5 mm, and the material between surface 4 and surface 5 is silicon. Surface 5 is a spherical surface, and its radius of curvature is infinite, that is, surface 5 is a plane, the distance between surface 5 and surface 6 is 0.23 mm, and the material between surface 5 and surface 6 is air.

[0097] See also Figure 2 , Figure 2 FIG. 1 shows the MTF field curve of the far-infrared optical system 100 provided in Example 1. Figure 2 The horizontal axis in is the Y-axis field of view, and its unit is degree. Figure 2 The vertical axis is the MTF value. Figure 2 The sagittal curve S1 and the meridional curve T1 of the MTF with 7lp / mm spatial frequency as the field of view changes, and the sagittal curve S2 and the meridional curve T2 of the MTF with 14lp / mm spatial frequency as the field of view changes are listed in the table. Figure 2 It can be seen that at a spatial frequency of 14lp / mm, within a field of view of 0.8 (58.4°), the MTF of the far-infrared optical system 100 is greater than 0.62, and the imaging quality of the far-infrared optical system 100 is excellent.

[0098] Example 2

[0099] Figure 3 FIG. 1 shows a schematic diagram of the architecture layout of the far-infrared optical system 100 provided in Example 2. Figure 3 The mid-infrared optical system 100 includes, along the optical axis S from the object plane A to the image plane B, an aperture 20, a super lens 10, and a protective glass 30, wherein the aperture 20 is disposed on the object side of the super lens 10. Some parameters of the far-infrared optical system 100 provided in Example 2 are shown in Table 2-1.

[0100] Table 2-1. Partial parameters of the far-infrared optical system 100 provided in Example 2

[0101]

[0102]

[0103] As can be seen from Table 2-1, the working band of the far-infrared optical system 100 is 8 microns to 12 microns, and the central wavelength is 10 microns. The total optical length of the far-infrared optical system 100 is relatively short, only 1.545 mm, so the volume of the far-infrared optical system 100 provided in Example 2 is relatively small. The F number of the far-infrared optical system 100 is 1.2, which can greatly increase the amount of light entering the far-infrared optical system 100, and when the image sensor has a low response to light energy, the energy entering the far-infrared optical system 100 is collected as much as possible, thereby ensuring excellent imaging quality.

[0104] Along the optical axis S from the object plane A to the image plane B, starting from the aperture 20, each surface in the far-infrared optical system 100 is numbered, and the parameters of each surface are summarized to obtain the following Table 2-2.

[0105] Table 2-2. Parameters of various surfaces in the far-infrared optical system 100 provided in Example 2

[0106] Surface serial number Surface type Curvature radius (mm) Thickness(mm) Material 1 Aperture unlimited 0.22 - 2 Spherical unlimited 0.375 silicon 3 Structural surface unlimited 0.10 - 4 Spherical unlimited 0.50 silicon 5 Spherical unlimited 0.35 - 6 Image plane unlimited - -

[0107] The analysis of each surface in Table 2-2 can refer to Example 1, and no further analysis is performed in this example.

[0108] See also Figure 4 , Figure 4 FIG. 2 shows the MTF field curve of the far-infrared optical system 100 provided in Example 2. Figure 4 The horizontal axis in is the Y-axis field of view, and its unit is degree. Figure 4 The vertical axis is the MTF value. Figure 4 The sagittal curve S1 and the meridional curve T1 of the MTF with 7lp / mm spatial frequency as the field of view changes, and the sagittal curve S2 and the meridional curve T2 of the MTF with 14lp / mm spatial frequency as the field of view changes are listed in the table. Figure 4 It can be seen that at a spatial frequency of 14lp / mm, within a field of view of 0.8 (58.4°), the MTF of the far-infrared optical system 100 is greater than 0.6, and the imaging quality of the far-infrared optical system 100 is excellent.

[0109] Example 3

[0110] Figure 5 FIG. 1 shows a schematic diagram of the architecture layout of the far-infrared optical system 100 provided in Example 3. Figure 5 The mid-infrared optical system 100 includes, along the optical axis S, from the object plane A to the image plane B, an aperture 20, a super lens 10, and a protective glass 30, wherein the aperture 20 is disposed on the object side of the super lens 10. Some parameters of the far-infrared optical system 100 provided in Example 3 are shown in Table 3-1.

[0111] Table 3-1. Partial parameters of the far-infrared optical system 100 provided in Example 3

[0112] parameter data Total optical length (TTL) 1.52mm Maximum field of view (2ω) 146° F-number 1.4 Effective focal length 0.62mm Working band 8μm-12μm

[0113] As can be seen from Table 3-1, the working band of the far-infrared optical system 100 is 8 microns to 12 microns, and the central wavelength is 10 microns. The total optical length of the far-infrared optical system 100 is relatively short, only 1.52 mm, so 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 1.4, which can greatly increase the amount of light entering the far-infrared optical system 100, and when the image sensor has a low response to light energy, the energy entering the far-infrared optical system 100 is collected as much as possible, thereby ensuring excellent imaging quality.

[0114] Along the optical axis S from the object plane A to the image plane B, starting from the aperture 20, each surface in the far-infrared optical system 100 is numbered, and the parameters of each surface are summarized to obtain the following Table 1-2.

[0115] Table 3-2. Parameters of various surfaces in the far-infrared optical system 100 provided in Example 3

[0116] Surface serial number Surface type Curvature radius (mm) Thickness(mm) Material 1 Aperture unlimited 0.24 - 2 Spherical unlimited 0.30 silicon 3 Structural surface unlimited 0.13 - 4 Spherical unlimited 0.50 silicon 5 Spherical unlimited 0.35 - 6 Image plane unlimited - -

[0117] The analysis of each surface in Table 3-2 can refer to Example 1, and no further analysis is performed in this example.

[0118] See also Figure 6 , Figure 6 FIG. 1 shows the MTF field curve of the far-infrared optical system 100 provided in Example 3. Figure 6 The horizontal axis in is the Y-axis field of view, and its unit is degree. Figure 6 The vertical axis is the MTF value. Figure 6 The sagittal curve S1 and the meridional curve T1 of the MTF with 7lp / mm spatial frequency as the field of view changes, and the sagittal curve S2 and the meridional curve T2 of the MTF with 14lp / mm spatial frequency as the field of view changes are listed in the table. Figure 6 It can be seen that at a spatial frequency of 14lp / mm, within a field of view of 0.8 (58.4°), the MTF of the far-infrared optical system 100 is greater than 0.42, and the imaging quality of the far-infrared optical system 100 is excellent.

[0119] Example 4

[0120] Figure 7 FIG. 1 shows a schematic diagram of the architecture layout of the far-infrared optical system 100 provided in Example 4. Figure 7The mid-infrared optical system 100 includes, from the object plane A to the image plane B along the optical axis S, an aperture 20, a super lens 10, and a protective glass 30, wherein the aperture 20 is disposed on the object side of the super lens 10. Some parameters of the far-infrared optical system 100 provided in Example 4 are shown in Table 4-1.

[0121] Table 4-1. Partial parameters of the far-infrared optical system 100 provided in Example 4

[0122] parameter data Total optical length (TTL) 1.46mm Maximum field of view (2ω) 146° F-number 0.95 Effective focal length 0.60mm Working band 8μm-12μm

[0123] As can be seen from Table 4-1, the working band of the far-infrared optical system 100 is 8 microns to 12 microns, and the central wavelength is 10 microns. The total optical length of the far-infrared optical system 100 is relatively short, only 1.46 mm, so 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 0.95, which can greatly increase the amount of light entering the far-infrared optical system 100, and when the image sensor has a low response to light energy, the energy entering the far-infrared optical system 100 is collected as much as possible, thereby ensuring excellent imaging quality.

[0124] Along the optical axis S from the object plane A to the image plane B, starting from the aperture 20, each surface in the far-infrared optical system 100 is numbered, and the parameters of each surface are summarized to obtain the following Table 4-2.

[0125] Table 4-2. Parameters of various surfaces in the far-infrared optical system 100 provided in Example 4

[0126] Surface serial number Surface type Curvature radius (mm) Thickness(mm) Material 1 Aperture unlimited 0.23 - 2 Spherical unlimited 0.30 silicon 3 Structural surface unlimited 0.08 - 4 Spherical unlimited 0.50 silicon 5 Spherical unlimited 0.35 - 6 Image plane unlimited - -

[0127] The analysis of each surface in Table 4-2 can refer to Example 1, and no further analysis is performed in this example.

[0128] See also Figure 8 , Figure 8 FIG. 4 shows the MTF field curve of the far-infrared optical system 100 provided in Example 4. Figure 8 The horizontal axis in is the Y-axis field of view, and its unit is degree. Figure 8 The vertical axis is the MTF value. Figure 8 The sagittal curve S1 and the meridional curve T1 of the MTF with 7lp / mm spatial frequency as the field of view changes, and the sagittal curve S2 and the meridional curve T2 of the MTF with 14lp / mm spatial frequency as the field of view changes are listed in the table. Figure 8 It can be seen that at a spatial frequency of 14lp / mm, within a field of view of 0.8 (58.4°), the MTF of the far-infrared optical system 100 is greater than 0.5, and the imaging quality of the far-infrared optical system 100 is excellent.

[0129] Example 5

[0130] Fig. 9 FIG. 1 shows a schematic diagram of the architecture layout of the far-infrared optical system 100 provided in Example 5. Fig. 9 The mid-infrared optical system 100 includes, along the optical axis S from the object plane A to the image plane B, an aperture 20 and a super lens 10, wherein the aperture 20 is disposed on the object side of the super lens 10. Some parameters of the far-infrared optical system 100 provided in Example 5 are shown in Table 5-1.

[0131] Table 5-1. Partial parameters of the far-infrared optical system 100 provided in Example 5

[0132] parameter data Total optical length (TTL) 1.21mm Maximum field of view (2ω) 148° F-number 0.95 Effective focal length 0.39mm Working band 8μm-12μm

[0133] As can be seen from Table 5-1, the working band of the far-infrared optical system 100 is 8 microns to 12 microns, and the central wavelength is 10 microns. The total optical length of the far-infrared optical system 100 is relatively short, only 1.21 mm, so the volume of the far-infrared optical system 100 provided in Example 5 is relatively small. The F number of the far-infrared optical system 100 is 0.95, which can greatly increase the amount of light entering the far-infrared optical system 100, and when the image sensor has a low response to light energy, the energy entering the far-infrared optical system 100 is collected as much as possible, thereby ensuring excellent imaging quality.

[0134] Along the optical axis S from the object plane A to the image plane B, starting from the aperture 20, each surface in the far-infrared optical system 100 is numbered, and the parameters of each surface are summarized to obtain the following Table 5-2.

[0135] Table 5-2. Parameters of various surfaces in the far-infrared optical system 100 provided in Example 5

[0136] Surface serial number Surface type Curvature radius (mm) Thickness(mm) Material 1 Aperture unlimited 0.11 - 2 Spherical unlimited 0.50 silicon 3 Structural surface unlimited 0.60 - 4 Image plane unlimited - -

[0137] The analysis of each surface in Table 5-2 can refer to Example 1, and no further analysis is performed in this example.

[0138] See also Fig.10 , Fig.10 FIG. 5 shows the MTF field curve of the far-infrared optical system 100 provided in Example 5. Fig.10 The horizontal axis in is the Y-axis field of view, and its unit is degree. Fig.10 The vertical axis is the MTF value. Fig.10 The sagittal curve S1 and the meridional curve T1 of the MTF with 7lp / mm spatial frequency as the field of view changes, and the sagittal curve S2 and the meridional curve T2 of the MTF with 14lp / mm spatial frequency as the field of view changes are listed in the table. Fig.10It can be seen that at a spatial frequency of 14lp / mm, within a field of view of 0.9 (66.6°), the MTF of the far-infrared optical system 100 is greater than 0.32, and the imaging quality of the far-infrared optical system 100 is excellent.

[0139] Example 6

[0140] Fig.11 FIG. 1 shows a schematic diagram of the architecture layout of the far-infrared optical system 100 provided in Example 6. Fig.11 The mid-infrared optical system 100 includes, from the object plane A to the image plane B along the optical axis S, an aperture 20, a super lens 10, and a protective glass 30, wherein the aperture 20 is disposed on the object side of the super lens 10. Some parameters of the far-infrared optical system 100 provided in Example 6 are shown in Table 6-1.

[0141] Table 6-1. Partial parameters of the far-infrared optical system 100 provided in Example 6

[0142] parameter data Total optical length (TTL) 1.43mm Maximum field of view (2ω) 148° F-number 0.90 Effective focal length 0.64 Working band 8μm-12μm

[0143] As can be seen from Table 6-1, the working band of the far-infrared optical system 100 is 8 microns to 12 microns, and the central wavelength is 10 microns. The total optical length of the far-infrared optical system 100 is relatively short, only 1.43 mm, so the volume of the far-infrared optical system 100 provided in Example 6 is relatively small. The F number of the far-infrared optical system 100 is 0.90, which can greatly increase the amount of light entering the far-infrared optical system 100, and when the image sensor has a low response to light energy, the energy entering the far-infrared optical system 100 is collected as much as possible, thereby ensuring excellent imaging quality.

[0144] Along the optical axis S from the object plane A to the image plane B, starting from the aperture 20, each surface in the far-infrared optical system 100 is numbered, and the parameters of each surface are summarized to obtain the following Table 6-2.

[0145] Table 6-2. Parameters of various surfaces in the far-infrared optical system 100 provided in Example 6

[0146] Surface serial number Surface type Curvature radius (mm) Thickness(mm) Material 1 Aperture unlimited 0.33 - 2 Spherical unlimited 0.50 silicon 3 Structural surface unlimited 0.60 - 4 Image plane unlimited - -

[0147] The analysis of each surface in Table 6-2 can refer to Example 1, and no further analysis is performed in this example.

[0148] See also Fig.12 , Fig.12 FIG. 1 shows the MTF field curve of the far-infrared optical system 100 provided in Example 6. Fig.12 The horizontal axis in is the Y-axis field of view, and its unit is degree. Fig.12 The vertical axis is the MTF value. Fig.12The sagittal curve S1 and the meridional curve T1 of the MTF with 7lp / mm spatial frequency as the field of view changes, and the sagittal curve S2 and the meridional curve T2 of the MTF with 14lp / mm spatial frequency as the field of view changes are listed in the table. Fig.12 It can be seen that at a spatial frequency of 14lp / mm, within a field of view of 0.8 (59.2°), the MTF of the far-infrared optical system 100 is greater than 0.58, and the imaging quality of the far-infrared optical system 100 is excellent.

[0149] Example 7

[0150] Fig.13 FIG. 1 shows a schematic diagram of the architecture layout of the far-infrared optical system 100 provided in Example 7. Fig.13 The mid-infrared optical system 100 includes, in order from the object plane A to the image plane B along the optical axis S: an aperture 20, a super lens 10, and a protective glass 30, wherein the aperture 20 is disposed on the object side of the super lens 10. Some parameters of the far-infrared optical system 100 provided in Example 7 are shown in Table 7-1.

[0151] Table 7-1. Partial parameters of the far-infrared optical system 100 provided in Example 7

[0152] parameter data Total optical length (TTL) 1.48mm Maximum field of view (2ω) 148° F-number 0.9 Effective focal length 0.43mm Working band 8μmm-12μmm

[0153] As can be seen from Table 7-1, the working band of the far-infrared optical system 100 is 8 microns to 12 microns, and the central wavelength is 10 microns. The total optical length of the far-infrared optical system 100 is relatively short, only 1.48 mm, so the volume of the far-infrared optical system 100 provided in Example 7 is relatively small. The F number of the far-infrared optical system 100 is 0.9, which can greatly increase the amount of light entering the far-infrared optical system 100, and when the image sensor has a low response to light energy, the energy entering the far-infrared optical system 100 is collected as much as possible, thereby ensuring excellent imaging quality.

[0154] Along the optical axis S from the object plane A to the image plane B, starting from the aperture 20, each surface in the far-infrared optical system 100 is numbered, and the parameters of each surface are summarized to obtain the following Table 7-2.

[0155] Table 7-2. Parameters of various surfaces in the far-infrared optical system 100 provided in Example 7

[0156] Surface serial number Surface type Curvature radius (mm) Thickness(mm) Material 1 Aperture unlimited 0.155 - 2 Structural surface unlimited 0.725 silicon 3 Structural surface unlimited 0.600 - 4 Image plane unlimited - -

[0157] The analysis of each surface in Table 7-2 can refer to Example 1, and no further analysis is performed in this example.

[0158] See also Fig.14 , Fig.14FIG. 1 shows the MTF field curve of the far-infrared optical system 100 provided in Example 7. Fig.14 The horizontal axis in is the Y-axis field of view, and its unit is degree. Fig.14 The vertical axis is the MTF value. Fig.14 The sagittal curve S1 and the meridional curve T1 of the MTF with 7lp / mm spatial frequency as the field of view changes, and the sagittal curve S2 and the meridional curve T2 of the MTF with 14lp / mm spatial frequency as the field of view changes are listed in the table. Fig.14 It can be seen that at a spatial frequency of 14lp / mm, within a field of view of 0.8 (59.2°), the MTF of the far-infrared optical system 100 is greater than 0.4, and the imaging quality of the far-infrared optical system 100 is excellent.

[0159] After summarizing the various parameters of the far-infrared optical system 100 provided by the above 7 embodiments, the following Table 8 is obtained. The display of Table 8 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.

[0160] Table 8. Parameters of the far-infrared optical system 100 provided in various embodiments

[0161]

[0162]

[0163] This application also provides a far-infrared optical lens, see Fig.15 , Fig.15 The schematic diagram of the partial structure of the far-infrared optical lens is shown, and the far-infrared optical lens includes an imaging detector (not shown) and the above-mentioned far-infrared optical system 100. The architecture of the far-infrared optical system 100 can be found above and will not be repeated here. 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).

[0164] Please refer again Fig.15The far-infrared optical lens also includes a lens barrel 200, which is roughly cylindrical and is provided with a through hole 2001. The through hole 2001 includes a first hole segment 2001a, a second hole segment 2001a, a third hole segment 2001c, and a fourth hole segment 2001d that are connected in sequence. The diameter of the second hole segment 2001a is smaller than the diameter of the third hole segment 2001c, and the diameter of the third hole segment 2001c is smaller than the diameter of the fourth hole segment 2001d. The second hole segment 2001a plays the role of the diaphragm 20, that is, the second hole segment 2001a is an aperture diaphragm 20. By accurately controlling the depth of the third hole segment 2001c, the distance between the diaphragm 20 and the super lens 10 can be accurately controlled. The super lens 10 is accommodated in the fourth hole segment 2001d to install the super lens 10.

[0165] In some embodiments, the first hole segment 2001a is a conical hole, and the diameter of the first hole segment 2001a gradually decreases along the optical axis S from the object side to the image side, so that incident light with a larger angle with the optical axis S can also enter the far-infrared optical system 100, thereby improving the relative illumination of the image formed by the far-infrared optical lens.

[0166] In some embodiments, the superlens 10 is adhesively connected to the lens barrel 200 to fix the superlens 10 .

[0167] In some embodiments, the far-infrared optical lens further includes a gland (not shown), which is located on the side of the lens barrel 200 away from the aperture 20, and is connected to the lens barrel 200 to fix the metalens 10. The connection between the gland and the lens barrel 200 includes but is not limited to bonding, threaded connection, and clamping.

[0168] 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 comprises: a super lens, the optical focal power of the super lens is positive, and the super lens comprises: a substrate and a micro-nano structure; at least one of the object side surface of the substrate and the image side surface of the substrate is provided with the micro-nano structure; The far-infrared optical system satisfies: 4D≤ΔΦ m ≤1000D, where the ΔΦ m is the difference between the maximum optical focal length and the minimum optical focal length of the metalens in the working band, and D=m -1 .

2. The far-infrared optical system according to claim 1, characterized in that: The far-infrared optical system meets the following requirements: Among them, the Φ m is the optical power provided by the metalens at the central wavelength, and the T m is the thickness of the superlens.

3. The far-infrared optical system according to claim 1, characterized in that: The far-infrared optical system meets the following requirements: The surface of the substrate provided with the micro-nano structure is a structural surface, and the surface with the largest phase value provided by each of the structural surfaces is a first target structural surface. is the maximum phase value provided by the first target structure surface; the r m is the effective area radius of the metalens, and p represents a radian of 2π.

4. The far-infrared optical system according to claim 1, characterized in that: The far-infrared optical system meets the following requirements: The surface of the substrate provided with the micro-nano structure is a structural surface, and the surface having the largest difference between the maximum spatial phase gradient and the minimum spatial phase gradient at the central wavelength is a second target structural surface. is the maximum spatial phase gradient provided by the second target structure surface at the central wavelength, It is the minimum spatial phase gradient provided by the second target structure surface at the central wavelength.

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 TTL is the total optical length of the far-infrared optical system, the ImgH is the imaging area radius of the far-infrared optical system on the image plane corresponding to the maximum half field of view angle, the BFL is the optical back focal length of the far-infrared optical system, and f is the effective focal length of the far-infrared optical system.

6. The far-infrared optical system according to claim 1, characterized in that: The far-infrared optical system meets the following requirements: Wherein, ImgH is the imaging area radius of the far-infrared optical system on the image plane corresponding to the maximum half field angle, and E L is the maximum vertical axis chromatic aberration of the far-infrared optical system, and F# is the aperture number of the far-infrared optical system.

7. The far-infrared optical system according to any one of claims 1 to 6, characterized in that: The far-infrared optical system also includes an aperture, and the aperture and the super lens are arranged in sequence along the direction from the object side to the image side of the optical axis.

8. The far-infrared optical system according to claim 7, characterized in that: The far-infrared optical system meets the following requirements: The L1 is the distance between the image side surface of the aperture and the image side surface of the super lens on the optical axis, and the TTL is the total optical length of the far-infrared optical system.

9. 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 8, and the imaging detector is arranged on the image plane of the far-infrared optical system.

10. The far-infrared optical lens according to claim 9, characterized in that: The far-infrared optical lens also includes a lens barrel, which is provided with a through hole, and the through hole includes a first hole segment, a second hole segment, a third hole segment, and a fourth hole segment that are connected in sequence, the diameter of the second hole segment is smaller than the diameter of the third hole segment, and the diameter of the third hole segment is smaller than the diameter of the fourth hole segment; the super lens is accommodated in the fourth hole segment.

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