Far infrared optical system and far infrared optical lens

Abstract

The invention discloses a far infrared optical system and a far infrared optical lens. The far infrared optical system sequentially comprises a first aspheric lens, a super lens and a second aspheric lens from an object side to an image side along an optical axis, the focal power of the first aspheric lens is positive, and the object side surface and the image side surface of the first aspheric lens both protrude towards the object side; the focal power of the super lens is positive; the focal power of the second aspheric lens is positive, and the object side surface and the image side surface of the second aspheric lens both protrude towards the object side; the far infrared optical system meets the following conditions: phi a1 + phi m is less than phi a2, phi m is less than or equal to phi a1, and phi a1, phi m and phi a2 are respectively the focal power of the first aspheric lens, the focal power of the super lens and the focal power of the second aspheric lens. The far infrared optical system provided by the invention can reduce the risk of generating annular stray light on the premise of having excellent imaging quality and smaller system volume, and has higher transmittance. The super lens has good machinability, high production efficiency and low production cost, and the production cost and the size of the far infrared optical system can be reduced.

Description

Technical Field

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

[0002] Since the concept of binary optics was proposed, the application of diffractive optical elements has developed rapidly. Diffractive surfaces are a common type of diffractive optical element, which has good achromatic and athermal effects. In the prior art, some far-infrared optical systems have good achromatic and athermal effects by combining diffractive surfaces with refractive elements and / or reflective elements.

[0003] Although the use of diffractive surfaces can improve the design freedom of far-infrared optical systems and provide new ideas for reducing the volume of the system, the introduction of diffractive surfaces makes the far-infrared optical system at risk of generating annular stray light, and the diffractive surfaces also have problems such as low transmittance, high processing difficulty, and low production efficiency. Summary of the invention

[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 solve at least one of the above problems.

[0005] According to one aspect of an embodiment of the present application, a far-infrared optical system is disclosed, and the far-infrared optical system includes, in order from the object side to the image side along the optical axis: a first aspheric lens, a super lens, and a second aspheric lens; the optical power of the first aspheric lens is positive, the object side surface of the first aspheric lens is convex toward the object side, and the image side surface of the first aspheric lens is convex toward the object side; the optical power of the super lens is positive; the optical power of the second aspheric lens is positive, the object side surface of the second aspheric lens is convex toward the object side, and the image side surface of the second aspheric lens is convex toward the object side;

[0006] The far-infrared optical system satisfies: Φ a1 +Φ m <Φ a2 , Φ m ≤Φ a1 , where the Φ a1 is the focal length of the first aspheric lens, the Φ m is the optical power of the metalens, the Φ a2 is the optical power of the second aspherical lens.

[0007] In some embodiments, the far-infrared optical system satisfies: Wherein, f is the effective focal length of the far-infrared optical system, and f a1 is the focal length of the first aspheric lens, and the f a2is the focal length of the second aspheric lens, the f m is the focal length of the metalens.

[0008] In some embodiments, the far-infrared optical system satisfies: Among them, the f a1 is the focal length of the first aspheric lens, and the f a2 is the focal length of the second aspheric lens, D1 is the maximum effective diameter of the first aspheric lens, and D2 is the maximum effective diameter of the second aspheric lens.

[0009] In some embodiments, the far-infrared optical system satisfies: Among them, the L 13 is the distance between the image side surface of the first aspheric lens and the object side surface of the second aspheric lens on the optical axis, the TTL is the total optical length of the far-infrared optical system, and the FOV is the maximum field of view angle of the far-infrared optical system.

[0010] In some embodiments, the far-infrared optical system satisfies: Wherein, the Sag1 is the sag height of the object side surface of the first aspheric lens at the maximum effective diameter; and the R1 is the radius of curvature of the object side surface of the first aspheric lens.

[0011] In some embodiments, the far-infrared optical system satisfies: D1 is the maximum effective diameter of the first aspheric lens, m is the maximum effective diameter of the super lens, and D2 is the maximum effective diameter of the second aspheric lens.

[0012] In some embodiments, the far-infrared optical system satisfies: Among them, f is the effective focal length of the far-infrared optical system, n is the refractive index of the first aspheric lens, FNO is the aperture number of the far-infrared optical system, and R1 is the curvature radius of the object side of the first aspheric lens.

[0013] In some embodiments, the far-infrared optical system satisfies: Wherein, D1 is the maximum effective diameter of the first aspheric lens, D2 is the maximum effective diameter of the second aspheric lens, and L 13 is the distance between the image side surface of the first aspheric lens and the object side surface of the second aspheric lens on the optical axis, and L B is the distance between the image side surface of the second aspherical lens and the image plane of the far-infrared optical system on the optical axis, and f is the effective focal length of the far-infrared optical system.

[0014] In some embodiments, the far-infrared optical system further includes an aperture, and the aperture is disposed on the object side of the first aspheric lens; or, the aperture is disposed between any two adjacent lenses.

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

[0016] The far-infrared optical system provided by the present application comprises, in order from the object side to the image side along the optical axis: a first aspheric lens, a super lens and a second aspheric lens; the optical power of the first aspheric lens is positive, the object side surface of the first aspheric lens is convex to the object side, and the image side surface of the first aspheric lens is convex to the object side; the optical power of the super lens is positive; the optical power of the second aspheric lens is positive, the object side surface of the second aspheric lens is convex to the object side, and the image side surface of the second aspheric lens is convex to the object side; the far-infrared optical system satisfies: Φ a1 +Φ m <Φ a2 , Φ m ≤Φ a1 , where Φ a1 is the focal power of the first aspheric lens, Φ m is the focal power of the metalens, Φ a2 is the optical focal length of the second aspheric lens. In the present application, the far-infrared optical system has excellent imaging quality and a small volume. Compared with the far-infrared optical system using a diffraction surface in the prior art, the far-infrared optical system provided by the present application can reduce the risk of generating annular stray light while having excellent imaging quality and a small system volume, and has a higher transmittance. Compared with the diffraction surface, the superlens can be processed by semiconductor technology, and its processing technology is compatible with the existing semiconductor processing technology, so that the superlens has good processability, high production efficiency, and low production cost, which can reduce the production cost and volume of the far-infrared optical system. 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 phase diagram of the metalens of the far-infrared optical system in one embodiment of the present application is shown.

[0020] Figure 3The MTF field of view curve of the far-infrared optical system in one embodiment of the present application is shown.

[0021] Figure 4 A field curvature curve diagram of a far-infrared optical system in an embodiment of the present application is shown.

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

[0023] Figure 6 A schematic diagram of the architecture layout of a far-infrared optical system in an embodiment of the present application is shown.

[0024] Figure 7 The phase diagram of the metalens of the far-infrared optical system in one 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. 9 A field curvature curve diagram of a far-infrared optical system in an embodiment of the present application is shown.

[0027] Fig.10 A distortion curve diagram of a far-infrared optical system in an 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 phase diagram of the metalens of the far-infrared optical system in one embodiment of the present application is shown.

[0030] Fig.13 The MTF field of view curve of the far-infrared optical system in one embodiment of the present application is shown.

[0031] Fig.14 A field curvature curve diagram of a far-infrared optical system in an embodiment of the present application is shown.

[0032] Fig.15 A distortion curve diagram of a far-infrared optical system in an embodiment of the present application is shown.

[0033] Fig.16 A schematic diagram of the architecture layout of a far-infrared optical system in an embodiment of the present application is shown.

[0034] Fig.17 The phase diagram of the metalens of the far-infrared optical system in one embodiment of the present application is shown.

[0035] Fig.18The MTF field of view curve of the far-infrared optical system in one embodiment of the present application is shown.

[0036] Fig.19 A field curvature curve diagram of a far-infrared optical system in an embodiment of the present application is shown.

[0037] Fig. 20 A distortion curve diagram of a far-infrared optical system in an embodiment of the present application is shown.

[0038] Fig.21 A schematic diagram of the architecture layout of a far-infrared optical system in an embodiment of the present application is shown.

[0039] Fig. 22 The phase diagram of the metalens of the far-infrared optical system in one embodiment of the present application is shown.

[0040] Fig.23 The MTF field of view curve of the far-infrared optical system in one embodiment of the present application is shown.

[0041] Fig.24 A field curvature curve diagram of a far-infrared optical system in an embodiment of the present application is shown.

[0042] Fig.25 A distortion curve diagram of a far-infrared optical system in an embodiment of the present application is shown.

[0043] Reference numerals

[0044] 100. Far infrared optical system;

[0045] 10. A first aspheric lens;

[0046] 20. Super lens; 210. Substrate; 220. Micro-nano structure;

[0047] 30. A second aspheric lens;

[0048] 40. Aperture;

[0049] 50. Protective glass;

[0050] 60. Object surface;

[0051] 70. Image plane;

[0052] 80. Optical axis. DETAILED DESCRIPTION

[0053] 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.

[0054] 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.

[0055] 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 80 is the center line of the light beam. Figure 1 In the figure, the object to be measured is located on the left side of the leftmost lens, that is, the object side is located on the left side of the leftmost lens, and the object plane 60 is located on the object side. The image formed by the far-infrared optical system 100 is located on the right side of the rightmost lens, that is, the image side is located on the right side of the rightmost lens, and the image plane 70 is located on the image side. Therefore, the direction from the object plane 60 to the image plane 70 along the optical axis 80 is consistent with the direction from the object side to the image side along the optical axis 80.

[0056] 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 40 close to the object side is the object side of the diaphragm 40. 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 40 close to the image side is the image side surface of the diaphragm 40.

[0057] The far-infrared optical system 100 includes a first aspheric lens 10 , a super lens 20 , and a second aspheric lens 30 , which are sequentially arranged along the optical axis 80 from the object side to the image side.

[0058] The first aspheric lens 10 has a positive refractive power, an object-side surface of the first aspheric lens 10 is convex toward the object side, and an image-side surface of the first aspheric lens 10 is convex toward the object side.

[0059] The optical power of the superlens 20 is positive. The superlens 20 includes a substrate 210 and a micro-nano structure 220. The micro-nano structure 220 is disposed on a surface of the substrate 210 close to the object side and / or a surface of the substrate 210 close to the image side.

[0060] The optical power of the second aspheric lens 30 is positive, the object-side surface of the second aspheric lens 30 is convex toward the object side, and the image-side surface of the second aspheric lens 30 is convex toward the object side.

[0061] The far-infrared optical system 100 satisfies the conditional formula 1: Φ a1 +Φ m <Φ a2 , Φ m ≤Φ a1 , where Φ a1 is the focal length of the first aspheric lens 10, Φ m is the focal power of the superlens 20, Φ a2 is the optical power of the second aspherical lens 30. a1 , Φ m , Φ a2 The dimensions are the same, which are all negative first powers of length units, such as mm -1 .

[0062] The optical power of the far-infrared optical system 100 can be reasonably allocated by conditional formula 1, ensuring that the second aspheric lens 30 is used to provide the main optical power, and ensuring that the super lens 20 is mainly used to correct aberrations in the full field of view and spherical aberrations in the edge field of view. In addition, the super lens 20 has negative dispersion, and the super lens 20 has a good achromatic effect when combined with the first aspheric lens 10 and the second aspheric lens 30, thereby ensuring that the far-infrared optical system 100 has excellent imaging quality.

[0063] In the present application, the far-infrared optical system 100 has excellent imaging quality and a small volume. Compared with the far-infrared optical system using a diffraction surface in the prior art, the far-infrared optical system 100 provided in the present application can reduce the risk of generating annular stray light and has a high transmittance while having excellent imaging quality and a small system volume. Compared with the diffraction surface, the superlens 20 can be processed by semiconductor technology, and its processing technology is compatible with the existing semiconductor processing technology, so that the superlens 20 has good processability, high production efficiency, and low production cost, which can reduce the production cost and volume of the far-infrared optical system 100.

[0064] It should be noted that, based on the principle of phase superposition, the target phase can be provided by one, two, or more than three super lenses 20, as long as the sum of the phases of each super lens 20 in the phase far-infrared optical system 100 is equal to the target phase. Therefore, the present application does not limit the number of super lenses 20, that is, the number of super lenses 20 in the far-infrared optical system 100 can be one, two, or more than three.

[0065] In some embodiments, the far-infrared optical system 100 satisfies conditional formula 2: Wherein, f is the effective focal length of the far-infrared optical system 100, and f a1 is the focal length of the first aspheric lens 10, f a2 is the focal length of the second aspherical lens 30, f m is the focal length of the super lens 20. f, f a1 、f a2 、f m have the same dimension, which is a unit of length, such as millimeter.

[0066] Conditional expression 2 indicates the focal power distribution relationship of the far-infrared optical system 100. Meeting conditional expression 2 is beneficial to the aberration correction of the far-infrared optical system 100, ensuring that the far-infrared optical system 100 provides excellent imaging quality.

[0067] In some embodiments, the far-infrared optical system 100 satisfies conditional formula 3: Among them, f a1 is the focal length of the first aspheric lens 10, f a2 is the focal length of the second aspheric lens 30. D1 is the maximum effective diameter of the first aspheric lens 10. In the present application, the maximum effective diameter of a lens refers to the larger of the maximum effective diameter of the object side of the lens and the maximum effective diameter of the image side of the lens; the maximum effective diameter of a certain surface of the lens refers to the diameter of the maximum light transmission area of ​​the surface corresponding to the lens, the same below. D2 is the maximum effective diameter of the second aspheric lens 30. a1 、f a2 , D1, and D2 have the same dimension, which is a length unit, such as millimeter.

[0068] The lower limit of conditional expression 3 can ensure that the far-infrared optical system 100 has a smaller volume and the aperture of the far-infrared optical system 100 is not too large. The upper limit of conditional expression 3 can reduce the tolerance sensitivity of the far-infrared optical system 100, which is conducive to improving the assembly yield of the far-infrared optical system 100.

[0069] In some embodiments, the far-infrared optical system 100 satisfies Condition 4: Among them, L 13L is the distance between the image side surface of the first aspheric lens 10 and the object side surface of the second aspheric lens 30 on the optical axis 80. TTL (Total Track Length, TTL for short) is the total optical length of the far-infrared optical system 100. FOV (Field of View, FOV for short) is the maximum field of view of the far-infrared optical system 100. The unit of FOV is degree. 13 , TTL have the same dimension, both are length units, such as millimeters.

[0070] The upper limit of conditional expression 4 can ensure that the far-infrared optical system 100 has a smaller total optical length, which is beneficial to reducing the volume of the far-infrared optical system 100. The lower limit of conditional expression 4 can ensure that the far-infrared optical system 100 has excellent imaging quality.

[0071] In some embodiments, the far-infrared optical system 100 satisfies Condition 5: Wherein, Sag1 is the sagittal height of the object side surface of the first aspheric lens 10 at the maximum effective diameter. Specifically, if the maximum effective diameter of the object side surface of the first aspheric lens 10 is 2a, then Sag1 is the sagittal height at a distance a from the center of the object side surface of the first aspheric lens 10. The sagittal height has positive and negative values. The judgment of the positive and negative values ​​of the sagittal height can refer to the prior art and will not be repeated herein. R1 is the radius of curvature of the object side surface of the first aspheric lens 10. Sag1 and R1 have the same dimension, both of which are length units, such as millimeters.

[0072] The upper limit of conditional formula 5 can avoid the first aspheric lens 10 from being too difficult to process, and at the same time, the upper limit of conditional formula 5 can also ensure that the first aspheric lens 10 has a good coating effect after coating. The lower limit of conditional formula 5 can ensure that the first aspheric lens 10 has sufficient optical power, thereby avoiding the metalens 20 and the second aspheric lens 30 from being too large in diameter.

[0073] In some embodiments, the far-infrared optical system 100 satisfies conditional formula 6: D1 is the maximum effective diameter of the first aspheric lens 10, D m D1 is the maximum effective diameter of the super lens 20, and D2 is the maximum effective diameter of the second aspheric lens 30. m , D2 have the same dimension, both are length units, such as millimeters.

[0074] Conditional expression 6 can ensure that the propagation path of light in the far-infrared optical system 100 is relatively smooth, which can reduce the overall tolerance sensitivity of the far-infrared optical system 100 and further improve the imaging quality of the far-infrared optical system 100 .

[0075] In some embodiments, the far-infrared optical system 100 satisfies conditional equation 7: Wherein, f is the effective focal length of the far-infrared optical system 100, and n is the refractive index of the first aspheric lens 10. FNO is the aperture number of the far-infrared optical system 100, that is, FNO is the F number of the far-infrared optical system 100. R1 is the radius of curvature of the object side surface of the first aspheric lens 10. f and R1 have the same dimension, both of which are length units, such as millimeters.

[0076] Conditional formula 7 can ensure that the far-infrared optical system 100 has good compatibility with the imaging detector of the target specification and has excellent imaging quality. The imaging detector of the target specification includes but is not limited to an imaging detector with a pixel number of 384×288 and a pixel size of 12 microns.

[0077] In some embodiments, the far-infrared optical system 100 satisfies Conditional Formula 8: Wherein, D1 is the maximum effective diameter of the first aspheric lens 10, D2 is the maximum effective diameter of the second aspheric lens 30, and L 13 is the distance between the image side surface of the first aspheric lens 10 and the object side surface of the second aspheric lens 30 on the optical axis 80, L B is the distance between the image side surface of the second aspherical lens 30 and the image plane 70 of the far-infrared optical system 100 on the optical axis 80, and f is the effective focal length of the far-infrared optical system 100. 13 , L B , f have the same dimension, both are length units, such as millimeters.

[0078] The upper limit of conditional formula eight can ensure that the far-infrared optical system 100 has a small volume while having excellent imaging quality. At the same time, the upper limit of conditional formula eight is conducive to reducing the sensitivity of the far-infrared optical system 100 to assembly coaxiality tolerance. The lower limit of conditional formula eight can ensure that the far-infrared optical system 100 has a small volume, a large field of view and a high relative illumination, thereby making the brightness of the image formed by the far-infrared optical system 100 more uniform.

[0079] The far-infrared optical system 100 further includes an aperture 40, which is used to control the amount of light entering the far-infrared optical system 100, thereby ensuring that the far-infrared optical system 100 can work effectively and generate high-quality images.

[0080] See also Figure 1 , Fig.11 and Fig.16 In some embodiments, the aperture 40 is disposed on the object side of the first aspheric lens 10. Specifically, the position where the aperture 40 is disposed satisfies any of the following conditions:

[0081] (1) The aperture 40 is disposed on the object side of the first aspheric lens 10, and the aperture 40 and the first aspheric lens 10 are spaced apart;

[0082] (2) The aperture 40 is disposed on the object side of the first aspheric lens 10 , and the aperture 40 is attached to the first aspheric lens 10 , that is, the aperture 40 is attached to the object side surface of the first aspheric lens 10 .

[0083] See also Figure 6 and Fig.21 In some embodiments, the aperture 40 is disposed between any two adjacent lenses. Specifically, the position where the aperture 40 is disposed satisfies any of the following conditions:

[0084] (1) The aperture 40 is located between the first aspheric lens 10 and the metalens 20, and the aperture 40 is attached to the image side surface of the first aspheric lens 10;

[0085] (2) the aperture 40 is located between the first aspheric lens 10 and the super lens 20, and the aperture 40 is located between the first aspheric lens 10 and the super lens 20;

[0086] (3) The aperture 40 is located between the first aspheric lens 10 and the super lens 20, and the aperture 40 is attached to the object side surface of the super lens 20;

[0087] (4) The aperture 40 is located between the super lens 20 and the second aspheric lens 30, and the aperture 40 is arranged in contact with the image side surface of the super lens 20;

[0088] (5) the aperture 40 is located between the super lens 20 and the second aspheric lens 30, and the aperture 40 is located between the super lens 20 and the second aspheric lens 30;

[0089] (6) The aperture 40 is located between the super lens 20 and the second aspheric lens 30 , and the aperture 40 is attached to the object side surface of the second aspheric lens 30 .

[0090] Furthermore, in some embodiments, when the aperture 40 is disposed on the object side of the first aspheric lens 10 , the far-infrared optical system 100 has better imaging quality than when the aperture 40 is disposed at other positions.

[0091] In some embodiments, the far-infrared optical system 100 further includes a protective glass 50, which is located on the image side of the second aspheric lens 30 and on the object side of the image plane 70. The protective glass 50 is used to protect the imaging detector disposed on the image plane 70 to reduce the probability of damage to the imaging detector.

[0092] The far-infrared optical system 100 provided by the present application has the following benefits:

[0093] (1) Total optical length (TTL) ≤ 30 mm;

[0094] (2) The MTF (Modulation Transfer Function, MTF for short) is greater than 0.36 at a cutoff frequency of 42 lp / mm within the field of view;

[0095] (3) Distortion ≤ 1%;

[0096] (4)F number ≤ 1.

[0097] The present application exemplarily provides five far-infrared optical systems 100 that meet usage requirements in five embodiments. Next, the far-infrared optical systems 100 provided by the various embodiments of the present application are introduced in detail.

[0098] Example 1

[0099] Figure 1 FIG. 1 shows a schematic diagram of the architecture layout of the far-infrared optical system 100 provided in Example 1. Figure 1 The mid-infrared optical system 100 includes, along the optical axis 80, from the object plane 60 to the image plane 70, an aperture 40, a first aspheric lens 10, a super lens 20, a second aspheric lens 30, and a protective glass 50, wherein the micro-nano structure 220 is disposed on the object side of the substrate 210. Some parameters of the far-infrared optical system 100 provided in Example 1 are shown in Table 1-1.

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

[0101] parameter data Total optical length (TTL) 28.11mm Maximum field of view (2ω) 17.30° F-number 1.0 Effective focal length 19.01mm Working band Far infrared (8μm-12μm)

[0102] As can be seen from Table 1-1, the total optical length of the far-infrared optical system 100 is relatively short, only 28.11 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 1.0, which can ensure that the far-infrared optical system 100 has a large amount of light entering, thereby ensuring excellent imaging quality.

[0103] Each surface in the far-infrared optical system 100 is numbered along the optical axis 80 from the object plane 60 to the image plane 70, and the parameters of each surface are summarized to obtain the following Table 1-2.

[0104] Table 1-2. Parameters of various surfaces in the far-infrared optical system 100 provided in Example 1

[0105]

[0106]

[0107] For each surface in Table 1-2, surface 1 is the aperture 40, surface 2 is the object side of the first aspheric lens 10, and surface 3 is the image side of the first aspheric lens 10. Surface 4 is the object side of the super lens 20. Since the micro-nano structure 220 is arranged on the image side of the substrate 210, that is, the micro-nano structure 220 is located on surface 4, surface 4 is recorded as the structural surface, and surface 5 is the image side of the super lens 20. Surface 6 is the object side of the second aspheric lens 30, and surface 7 is the image side of the second aspheric lens 30. Surface 8 is the object side of the protective glass 50, and surface 9 is the image side of the protective glass 50. Surface 10 is the image surface 70.

[0108] As can be seen from Table 1-2, the radius of curvature of surface 1 is infinite, that is, surface 1 is a plane, and the distance between surface 1 and surface 2 is -3.57 mm. The negative sign in "-3.57" indicates that the vertex of surface 2 is convex from surface 1 toward the object side. Surface 2 is an even-order aspheric surface, the radius of curvature of surface 2 is 12.46 mm, the distance between surface 2 and surface 3 is 3.09 mm, and the material between surface 2 and surface 3 is chalcogenide glass. Surface 3 is an even-order aspheric surface, the radius of curvature of surface 3 is 12.36 mm, the distance between surface 3 and surface 4 is 12.58 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 0.30 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 0.14 mm, and the material between surface 5 and surface 6 is air. Surface 6 is an even aspheric surface, the radius of curvature of surface 6 is 11.67 mm, the distance between surface 6 and surface 7 is 2.81 mm, and the material between surface 6 and surface 7 is chalcogenide glass. Surface 7 is an even aspheric surface, the radius of curvature of surface 7 is 14.57 mm, the distance between surface 7 and surface 8 is 8.49 mm, and the material between surface 7 and surface 8 is air. The radius of curvature of surface 8 is infinite, that is, surface 8 is a plane, the distance between surface 8 and surface 9 is 0.60 mm, and the material between surface 8 and surface 9 is silicon. The radius of curvature of surface 9 is infinite, that is, surface 9 is a plane, the distance between surface 9 and surface 10 is 0.10 mm, and the material between surface 9 and surface 10 is air.

[0109] Surface 2, surface 3, surface 6 and surface 7 are even-order aspheric surfaces, and their surface shapes satisfy the following relationship:

[0110]

[0111] Among them, Z(r) is the distance vector height from the vertex of the aspheric surface when the aspheric surface is at a height of r along the optical axis 80; c is the curvature of the aspheric surface, c=1 / R, R is the curvature radius of the aspheric surface; k is the cone coefficient; A, B, C, D... are the aspheric coefficients. The values ​​of k, A, B, C, D... of surface 2, surface 3, surface 6 and surface 7 can be obtained from Table 1-3.

[0112] Table 1-3. Coefficients of the even-order aspheric surfaces in the far-infrared optical system 100 provided in Example 1

[0113]

[0114] Please refer to Table 1-3. For surface 2, k is -8.65E-01, A is 5.75E-06, B is 8.11E-07, C is -9.94E-09, D is 2.30E-11, E is -4.40E-13, F is 2.14E-15, and G is -4.16E-18. The coefficients of the even-order aspheric surfaces of surface 3, surface 6, and surface 7 can be obtained from Table 1-3, and will not be elaborated here one by one.

[0115] See also Figure 2 , Figure 2 : shows a phase distribution diagram of the super lens 20 of the far-infrared optical system 100 provided in Example 1, Figure 2 The horizontal axis represents the distance from the center of the superlens 20. Figure 2 The vertical axis represents the phase. It is worth mentioning that Figure 2 The actual phase distribution of the superlens 20 in Example 1 is given. Since the phase is a periodic function about 2π, there is a relationship: (n is an integer), so it can be based on Figure 2 The phase of the superlens 20 in Example 1 is modulo 2π to achieve normalization processing to meet the needs of actual processing of the superlens 20.

[0116] See also Figure 3 , Figure 3 FIG. 1 shows the MTF field curve of the far-infrared optical system 100 provided in Example 1. Figure 3 The horizontal axis in is the image height, and its unit is millimeter, that is, the horizontal axis measures the field of view with the image height; Figure 3 The vertical axis is the MTF value. Figure 3 The MTF of 10lp / mm spatial frequency is listed as the sagittal curve S1 and the meridional curve T1 of the field of view, the MTF of 21lp / mm spatial frequency is listed as the sagittal curve S2 and the meridional curve T2 of the field of view, and the MTF of 42lp / mm spatial frequency is listed as the sagittal curve S3 and the meridional curve T3 of the field of view. Figure 3It can be seen that within the entire field of view, the MTF is greater than 0.36, and the imaging quality of the far-infrared optical system 100 is excellent.

[0117] See also Figure 4 , Figure 4 1 shows a field curvature diagram of the far-infrared optical system 100 provided in Example 1, Figure 4 The central horizontal axis is the field curvature, which is in millimeters; Figure 4 The vertical axis is the Y-axis field of view, and its unit is degree. Figure 4 S1 is the field curvature of far-infrared light with a wavelength of 8 microns in the sagittal direction, and T1 is the field curvature of far-infrared light with a wavelength of 8 microns in the meridional direction; S2 is the field curvature of far-infrared light with a wavelength of 10 microns in the sagittal direction, and T2 is the field curvature of far-infrared light with a wavelength of 10 microns in the meridional direction; S3 is the field curvature of far-infrared light with a wavelength of 12 microns in the sagittal direction, and T3 is the field curvature of far-infrared light with a wavelength of 12 microns in the meridional direction. Figure 4 It can be seen that the maximum field curvature of the far-infrared optical system 100 in the sagittal direction is 0.0293 mm, and the maximum field curvature of the far-infrared optical system 100 in the meridional direction is 0.1054 mm, which meets the requirements for field curvature in the excellent imaging quality standard.

[0118] See also Figure 5 , Figure 5 The distortion diagram of the far-infrared optical system 100 provided in Example 1 under far-infrared light with wavelengths of 8 microns, 10 microns and 12 microns is shown. Figure 5 The horizontal axis is distortion, and its unit is percentage; Figure 5 The vertical axis is the Y-axis field of view, and its unit is degree. Figure 5 M1 is the distortion curve of far-infrared light with a wavelength of 8 microns, M2 is the distortion curve of far-infrared light with a wavelength of 10 microns, and M3 is the distortion curve of far-infrared light with a wavelength of 12 microns. Figure 5 It can be seen that within the full field of view, the maximum distortion of the far-infrared optical system 100 is 0.85%, which is relatively small and meets the distortion requirement of the excellent imaging quality standard.

[0119] Example 2

[0120] Figure 6 FIG. 1 shows a schematic diagram of the architecture layout of the far-infrared optical system 100 provided in Example 2. Figure 6 The mid-infrared optical system 100 includes, along the optical axis 80, from the object plane 60 to the image plane 70, a first aspheric lens 10, an aperture 40, a super lens 20, a second aspheric lens 30, and a protective glass 50, wherein the micro-nano structure 220 is disposed on the image side of the substrate 210. Some parameters of the far-infrared optical system 100 provided in Example 2 are shown in Table 2-1.

[0121] Table 2-1. Partial parameters of the far-infrared optical system 100 provided in Example 2

[0122] parameter data Total optical length (TTL) 30.00mm Maximum field of view (2ω) 17.26° F-number 1.0 Effective focal length 19.07mm Working band Far infrared (8μm-12μm)

[0123] As can be seen from Table 2-1, the total optical length of the far-infrared optical system 100 is relatively short, only 30.00 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 1.0, which can ensure that the far-infrared optical system 100 has a large amount of light entering, thereby ensuring excellent imaging quality.

[0124] Each surface in the far-infrared optical system 100 is numbered along the optical axis 80 from the object plane 60 to the image plane 70, and the parameters of each surface are summarized to obtain the following Table 2-2.

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

[0126] Surface serial number Surface type Curvature radius (mm) Thickness(mm) Material 1 even aspherical surface 13.15 2.63 Chalcogenide glass 2 even aspherical surface 13.17 2.78 - 3 Aperture unlimited 8.88 - 4 Spherical unlimited 0.30 silicon 5 Structural surface unlimited 2.00 - 6 even aspherical surface 12.24 3.35 Chalcogenide glass 7 even aspherical surface 15.52 9.36 - 8 Spherical unlimited 0.60 silicon 9 Spherical unlimited 0.10 - 10 Image plane unlimited - -

[0127] The analysis of each surface in Table 2-2 can refer to Example 1, and this example will not be analyzed in detail.

[0128] Surface 1, surface 2, surface 6 and surface 7 are even-order aspheric surfaces, and their surface shapes satisfy the following relationship:

[0129]

[0130] Among them, Z(r) is the distance vector height from the vertex of the aspheric surface when the aspheric surface is at a height of r along the optical axis 80; c is the curvature of the aspheric surface, c=1 / R, R is the curvature radius of the aspheric surface; k is the cone coefficient; A, B, C, D... are the aspheric coefficients. The values ​​of k, A, B, C, D... of Surface 1, Surface 2, Surface 6 and Surface 7 can be obtained from Table 2-3.

[0131] Table 2-3. Coefficients of the even-order aspheric surfaces in the far-infrared optical system 100 provided in Example 2

[0132]

[0133] The coefficients of the even-order aspheric surfaces of surface 1, surface 2, surface 6 and surface 7 can be obtained from Table 2-3, and will not be described one by one in this embodiment.

[0134] See also Figure 7 , Figure 7 : shows a phase distribution diagram of the metalens 20 of the far-infrared optical system 100 provided in Example 2, Figure 7The horizontal axis represents the distance from the center of the superlens 20. Figure 7 The vertical axis represents the phase. It is worth mentioning that Figure 7 The actual phase distribution of the superlens 20 in Example 2 is given. Since the phase is a periodic function about 2π, there is a relationship: (n is an integer), so it can be based on Figure 7 The phase of the superlens 20 in Example 2 is modulo 2π to achieve normalization processing to meet the needs of actual processing of the superlens 20.

[0135] See also Figure 8 , Figure 8 FIG. 2 shows the MTF field curve of the far-infrared optical system 100 provided in Example 2. Figure 8 The horizontal axis in is the image height, and its unit is millimeter, that is, the horizontal axis measures the field of view with the image height; Figure 8 The vertical axis is the MTF value. Figure 8 The MTF of 10lp / mm spatial frequency is listed as the sagittal curve S1 and the meridional curve T1 of the field of view, the MTF of 21lp / mm spatial frequency is listed as the sagittal curve S2 and the meridional curve T2 of the field of view, and the MTF of 42lp / mm spatial frequency is listed as the sagittal curve S3 and the meridional curve T3 of the field of view. Figure 8 It can be seen that within the entire field of view, the MTF is greater than 0.45, and the imaging quality of the far-infrared optical system 100 is excellent.

[0136] See also Fig. 9 , Fig. 9 2 shows a field curvature diagram of the far-infrared optical system 100 provided in Example 2, Fig. 9 The central horizontal axis is the field curvature, which is in millimeters; Fig. 9 The vertical axis is the Y-axis field of view, and its unit is degree. Fig. 9 S1 is the field curvature of far-infrared light with a wavelength of 8 microns in the sagittal direction, and T1 is the field curvature of far-infrared light with a wavelength of 8 microns in the meridional direction; S2 is the field curvature of far-infrared light with a wavelength of 10 microns in the sagittal direction, and T2 is the field curvature of far-infrared light with a wavelength of 10 microns in the meridional direction; S3 is the field curvature of far-infrared light with a wavelength of 12 microns in the sagittal direction, and T3 is the field curvature of far-infrared light with a wavelength of 12 microns in the meridional direction. Fig. 9 It can be seen that the maximum field curvature of the far-infrared optical system 100 in the sagittal direction is 0.0043 mm, and the maximum field curvature of the far-infrared optical system 100 in the meridional direction is 0.0894 mm, which meets the requirements for field curvature in the excellent imaging quality standard.

[0137] See also Fig.10 , Fig.10 The distortion diagram of the far-infrared optical system 100 provided in Example 2 under far-infrared light with wavelengths of 8 microns, 10 microns and 12 microns is shown. Fig.10 The horizontal axis is distortion, and its unit is percentage; Fig.10 The vertical axis is the Y-axis field of view, and its unit is degree. Fig.10 M1 is the distortion curve of far-infrared light with a wavelength of 8 microns, M2 is the distortion curve of far-infrared light with a wavelength of 10 microns, and M3 is the distortion curve of far-infrared light with a wavelength of 12 microns. Fig.10 It can be seen that within the full field of view, the maximum distortion of the far-infrared optical system 100 is 0.92%, which is relatively small and meets the distortion requirement of the excellent imaging quality standard.

[0138] Example 3

[0139] Fig.11 FIG. 1 shows a schematic diagram of the architecture layout of the far-infrared optical system 100 provided in Example 3. Fig.11 The mid-infrared optical system 100 includes, along the optical axis 80, from the object plane 60 to the image plane 70, an aperture 40, a first aspheric lens 10, a super lens 20, a second aspheric lens 30, and a protective glass 50, wherein the micro-nano structure 220 is disposed on the object side of the substrate 210. Some parameters of the far-infrared optical system 100 provided in Example 3 are shown in Table 3-1.

[0140] Table 3-1. Partial parameters of the far-infrared optical system 100 provided in Example 3

[0141] parameter data Total optical length (TTL) 30.01mm Maximum field of view (2ω) 17.28° F-number 1.0 Effective focal length 19.06mm Working band Far infrared (8μm-12μm)

[0142] As can be seen from Table 3-1, the total optical length of the far-infrared optical system 100 is relatively short, only 30.01 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 1.0, which can ensure that the far-infrared optical system 100 has a large amount of light entering, thereby ensuring excellent imaging quality.

[0143] Each surface in the far-infrared optical system 100 is numbered along the optical axis 80 from the object plane 60 to the image plane 70, and the parameters of each surface are summarized to obtain the following Table 3-2.

[0144] Table 3-2. Parameters of various surfaces in the far-infrared optical system 100 provided in Example 3

[0145] Surface serial number Surface type Curvature radius (mm) Thickness(mm) Material 1 Aperture unlimited -3.53 - 2 even aspherical surface 13.06 3.03 Chalcogenide glass 3 even aspherical surface 12.83 13.67 - 4 Structural surface unlimited 0.30 silicon 5 Spherical unlimited 0.12 - 6 even aspherical surface 12.34 3.19 Chalcogenide glass 7 even aspherical surface 16.18 9.00 - 8 Spherical unlimited 0.60 silicon 9 Spherical unlimited 0.10 - 10 Image plane unlimited - -

[0146] The analysis of each surface in Table 3-2 can refer to Example 1, and this example will not be analyzed in detail.

[0147] Surface 2, surface 3, surface 6 and surface 7 are even-order aspheric surfaces, and their surface shapes satisfy the following relationship:

[0148]

[0149] Among them, Z(r) is the distance vector height from the vertex of the aspherical surface when the aspherical surface is at a height of r along the optical axis 80; c is the curvature of the aspherical surface, c = 1 / R, R is the radius of curvature of the aspherical surface; k is the cone coefficient; A, B, C, D... are the aspherical coefficients. The values ​​of k, A, B, C, D... of surface 2, surface 3, surface 6 and surface 7 can be obtained from Table 3-3.

[0150] Table 3-3. Coefficients of the even-order aspheric surfaces in the far-infrared optical system 100 provided in Example 3

[0151]

[0152] The coefficients of the even-order aspheric surfaces of surface 2, surface 3, surface 6 and surface 7 can be obtained from Table 3-3, and will not be elaborated one by one in this embodiment.

[0153] See also Fig.12 , Fig.12 : shows a phase distribution diagram of the super lens 20 of the far-infrared optical system 100 provided in Example 3, Fig.12 The horizontal axis represents the distance from the center of the superlens 20. Fig.12 The vertical axis represents the phase. It is worth mentioning that Fig.12 The actual phase distribution of the superlens 20 in Example 3 is given. Since the phase is a periodic function about 2π, there is a relationship: (n is an integer), so it can be based on Fig.12 The phase of the superlens 20 in Example 3 is modulo 2π to achieve normalization processing to meet the needs of actual processing of the superlens 20.

[0154] See also Fig.13 , Fig.13 FIG. 1 shows the MTF field curve of the far-infrared optical system 100 provided in Example 3. Fig.13 The horizontal axis in is the image height, and its unit is millimeter, that is, the horizontal axis measures the field of view with the image height; Fig.13 The vertical axis is the MTF value. Fig.13 The MTF of 10lp / mm spatial frequency is listed as the sagittal curve S1 and the meridional curve T1 of the field of view, the MTF of 21lp / mm spatial frequency is listed as the sagittal curve S2 and the meridional curve T2 of the field of view, and the MTF of 42lp / mm spatial frequency is listed as the sagittal curve S3 and the meridional curve T3 of the field of view. Fig.13 It can be seen that within the entire field of view, the MTF is greater than 0.38, and the imaging quality of the far-infrared optical system 100 is excellent.

[0155] See also Fig.14 , Fig.14 1 shows a field curvature diagram of the far-infrared optical system 100 provided in Example 3, Fig.14 The central horizontal axis is the field curvature, which is in millimeters; Fig.14 The vertical axis is the Y-axis field of view, and its unit is degree. Fig.14 S1 is the field curvature of far-infrared light with a wavelength of 8 microns in the sagittal direction, and T1 is the field curvature of far-infrared light with a wavelength of 8 microns in the meridional direction; S2 is the field curvature of far-infrared light with a wavelength of 10 microns in the sagittal direction, and T2 is the field curvature of far-infrared light with a wavelength of 10 microns in the meridional direction; S3 is the field curvature of far-infrared light with a wavelength of 12 microns in the sagittal direction, and T3 is the field curvature of far-infrared light with a wavelength of 12 microns in the meridional direction. Fig.14 It can be seen that the maximum field curvature of the far-infrared optical system 100 in the sagittal direction is 0.0155 mm, and the maximum field curvature of the far-infrared optical system 100 in the meridional direction is 0.0521 mm, which meets the requirements for field curvature in the excellent imaging quality standard.

[0156] See also Fig.15 , Fig.15 The distortion diagram of the far-infrared optical system 100 provided in Example 3 under far-infrared light with wavelengths of 8 microns, 10 microns and 12 microns is shown. Fig.15 The horizontal axis is distortion, and its unit is percentage; Fig.15 The vertical axis is the Y-axis field of view, and its unit is degree. Fig.15 M1 is the distortion curve of far-infrared light with a wavelength of 8 microns, M2 is the distortion curve of far-infrared light with a wavelength of 10 microns, and M3 is the distortion curve of far-infrared light with a wavelength of 12 microns. Fig.15 It can be seen that within the full field of view, the maximum distortion of the far-infrared optical system 100 is 1.0%, which is relatively small and meets the distortion requirement of the excellent imaging quality standard.

[0157] Example 4

[0158] Fig.16 FIG. 1 shows a schematic diagram of the architecture layout of the far-infrared optical system 100 provided in Example 4. Fig.16 The mid-infrared optical system 100 includes, along the optical axis 80, from the object plane 60 to the image plane 70, an aperture 40, a first aspheric lens 10, a super lens 20, a second aspheric lens 30, and a protective glass 50, wherein the micro-nano structure 220 is disposed on the object side of the substrate 210. Some parameters of the far-infrared optical system 100 provided in Example 4 are shown in Table 4-1.

[0159] Table 4-1. Partial parameters of the far-infrared optical system 100 provided in Example 4

[0160] parameter data Total optical length (TTL) 30.01mm Maximum field of view (2ω) 17.28° F-number 1.0 Effective focal length 19.12mm Working band Far infrared (8μm-12μm)

[0161] As can be seen from Table 4-1, the total optical length of the far-infrared optical system 100 is relatively short, only 30.00 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 1.0, which can ensure that the far-infrared optical system 100 has a large amount of light entering, thereby ensuring excellent imaging quality.

[0162] Each surface in the far-infrared optical system 100 is numbered along the optical axis 80 from the object plane 60 to the image plane 70, and the parameters of each surface are summarized to obtain the following Table 4-2.

[0163] Table 4-2. Parameters of various surfaces in the far-infrared optical system 100 provided in Example 4

[0164] Surface serial number Surface type Curvature radius (mm) Thickness(mm) Material 1 Aperture unlimited -3.06 - 2 even aspherical surface 14.26 4.05 Chalcogenide glass 3 even aspherical surface 13.62 7.55 - 4 Structural surface unlimited 0.30 silicon 5 Spherical unlimited 5.05 - 6 even aspherical surface 13.34 4.02 Chalcogenide glass 7 even aspherical surface 17.75 8.34 - 8 Spherical unlimited 0.60 silicon 9 Spherical unlimited 0.10 - 10 Image plane unlimited - -

[0165] The analysis of each surface in Table 4-2 can refer to Example 1, and this example will not be analyzed in detail.

[0166] Surface 2, surface 3, surface 6 and surface 7 are even-order aspheric surfaces, and their surface shapes satisfy the following relationship:

[0167]

[0168] Among them, Z(r) is the distance vector height from the vertex of the aspheric surface when the aspheric surface is at a height of r along the optical axis 80; c is the curvature of the aspheric surface, c = 1 / R, R is the radius of curvature of the aspheric surface; k is the cone coefficient; A, B, C, D... are the aspheric coefficients. The values ​​of k, A, B, C, D... of Surface 2, Surface 3, Surface 6 and Surface 7 can be obtained from Table 4-3.

[0169] Table 4-3. Coefficients of the even-order aspheric surfaces in the far-infrared optical system 100 provided in Example 4

[0170]

[0171] The coefficients of the even-order aspheric surfaces of surface 2, surface 3, surface 6 and surface 7 can be obtained from Table 4-3, and will not be described one by one in this embodiment.

[0172] See also Fig.17 , Fig.17 1 shows a phase distribution diagram of the metalens 20 of the far-infrared optical system 100 provided in Example 4, Fig.17 The horizontal axis represents the distance from the center of the superlens 20. Fig.17 The vertical axis represents the phase. It is worth mentioning that Fig.17 The actual phase distribution of the superlens 20 in Example 4 is given. Since the phase is a periodic function about 2π, there is a relationship: (n is an integer), so it can be based on Fig.17 The phase of the superlens 20 in Example 4 is modulo 2π to achieve normalization processing to meet the needs of actual processing of the superlens 20.

[0173] See also Fig.18 , Fig.18 FIG. 4 shows the MTF field curve of the far-infrared optical system 100 provided in Example 4. Fig.18 The horizontal axis in is the image height, and its unit is millimeter, that is, the horizontal axis measures the field of view with the image height; Fig.18 The vertical axis is the MTF value. Fig.18 The MTF of 10lp / mm spatial frequency is listed as the sagittal curve S1 and the meridional curve T1 of the field of view, the MTF of 21lp / mm spatial frequency is listed as the sagittal curve S2 and the meridional curve T2 of the field of view, and the MTF of 42lp / mm spatial frequency is listed as the sagittal curve S3 and the meridional curve T3 of the field of view. Fig.18 It can be seen that within the entire field of view, the MTF is greater than 0.46, and the imaging quality of the far-infrared optical system 100 is excellent.

[0174] See also Fig.19 , Fig.19 1 shows a field curvature diagram of the far-infrared optical system 100 provided in Example 4, Fig.19 The central horizontal axis is the field curvature, which is in millimeters; Fig.19 The vertical axis is the Y-axis field of view, and its unit is degree. Fig.19 S1 is the field curvature of far-infrared light with a wavelength of 8 microns in the sagittal direction, and T1 is the field curvature of far-infrared light with a wavelength of 8 microns in the meridional direction; S2 is the field curvature of far-infrared light with a wavelength of 10 microns in the sagittal direction, and T2 is the field curvature of far-infrared light with a wavelength of 10 microns in the meridional direction; S3 is the field curvature of far-infrared light with a wavelength of 12 microns in the sagittal direction, and T3 is the field curvature of far-infrared light with a wavelength of 12 microns in the meridional direction. Fig.19 It can be seen that the maximum field curvature of the far-infrared optical system 100 in the sagittal direction is 0.0434 mm, and the maximum field curvature of the far-infrared optical system 100 in the meridional direction is 0.1817 mm, which meets the requirements for field curvature in the excellent imaging quality standard.

[0175] See also Fig. 20 , Fig. 20 The distortion diagram of the far-infrared optical system 100 provided in Example 4 under far-infrared light with wavelengths of 8 microns, 10 microns and 12 microns is shown. Fig. 20 The horizontal axis is distortion, and its unit is percentage; Fig. 20 The vertical axis is the Y-axis field of view, and its unit is degree. Fig. 20M1 is the distortion curve of far-infrared light with a wavelength of 8 microns, M2 is the distortion curve of far-infrared light with a wavelength of 10 microns, and M3 is the distortion curve of far-infrared light with a wavelength of 12 microns. Fig. 20 It can be seen that within the full field of view, the maximum distortion of the far-infrared optical system 100 is 0.83%, which is relatively small and meets the distortion requirement of the excellent imaging quality standard.

[0176] Example 5

[0177] Fig.21 FIG. 1 shows a schematic diagram of the architecture layout of the far-infrared optical system 100 provided in Example 5. Fig.21 The mid-infrared optical system 100 includes, along the optical axis 80, from the object plane 60 to the image plane 70, a first aspheric lens 10, an aperture 40, a super lens 20, a second aspheric lens 30, and a protective glass 50, wherein the micro-nano structure 220 is disposed on the image side of the substrate 210. Some parameters of the far-infrared optical system 100 provided in Example 5 are shown in Table 5-1.

[0178] Table 5-1. Partial parameters of the far-infrared optical system 100 provided in Example 5

[0179] parameter data Total optical length (TTL) 29.22mm Maximum field of view (2ω) 17.25° F-number 1.0 Effective focal length 19.01mm Working band Far infrared (8μm-12μm)

[0180] As can be seen from Table 5-1, the total optical length of the far-infrared optical system 100 is relatively short, only 29.22 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 1.0, which can ensure that the far-infrared optical system 100 has a large amount of light entering, thereby ensuring excellent imaging quality.

[0181] Each surface in the far-infrared optical system 100 is numbered along the optical axis 80 from the object plane 60 to the image plane 70, and the parameters of each surface are summarized to obtain the following Table 5-2.

[0182] Table 5-2. Parameters of various surfaces in the far-infrared optical system 100 provided in Example 5

[0183] Surface serial number Surface type Curvature radius (mm) Thickness(mm) Material 1 even aspherical surface 13.17 2.65 Chalcogenide glass 2 even aspherical surface 13.29 8.11 - 3 Aperture unlimited 0.10 - 4 Spherical unlimited 0.30 silicon 5 Structural surface unlimited 4.87 - 6 even aspherical surface 12.34 3.17 Chalcogenide glass 7 even aspherical surface 15.64 9.32 - 8 Spherical unlimited 0.60 silicon 9 Spherical unlimited 0.10 - 10 Image plane unlimited - -

[0184] The analysis of each surface in Table 5-2 can refer to Example 1, and this example will not be analyzed in detail.

[0185] Surface 1, surface 2, surface 6 and surface 7 are even-order aspheric surfaces, and their surface shapes satisfy the following relationship:

[0186]

[0187] Among them, Z(r) is the distance vector height from the vertex of the aspherical surface when the aspherical surface is at a height of r along the optical axis 80; c is the curvature of the aspherical surface, c = 1 / R, R is the curvature radius of the aspherical surface; k is the cone coefficient; A, B, C, D... are the aspherical coefficients. The values ​​of k, A, B, C, D... of surface 1, surface 2, surface 6 and surface 7 can be obtained from Table 5-3.

[0188] Table 5-3. Coefficients of the even-order aspheric surfaces in the far-infrared optical system 100 provided in Example 5

[0189]

[0190] The coefficients of the even-order aspheric surfaces of surface 1, surface 2, surface 6 and surface 7 can be obtained from Table 5-3, and will not be elaborated one by one in this embodiment.

[0191] See also Fig. 22 , Fig. 22 : shows a phase distribution diagram of the super lens 20 of the far-infrared optical system 100 provided in Example 5, Fig. 22 The horizontal axis represents the distance from the center of the superlens 20. Fig. 22 The vertical axis represents the phase. It is worth mentioning that Fig. 22 The actual phase distribution of the superlens 20 in Example 5 is given. Since the phase is a periodic function about 2π, there is a relationship: (n is an integer), so it can be based on Fig. 22 The phase of the superlens 20 in Example 5 is modulo 2π to achieve normalization processing to meet the needs of actual processing of the superlens 20.

[0192] See also Fig.23 , Fig.23 FIG. 5 shows the MTF field curve of the far-infrared optical system 100 provided in Example 5. Fig.23 The horizontal axis in is the image height, and its unit is millimeter, that is, the horizontal axis measures the field of view with the image height; Fig.23 The vertical axis is the MTF value. Fig.23 The MTF of 10lp / mm spatial frequency is listed as the sagittal curve S1 and the meridional curve T1 of the field of view, the MTF of 21lp / mm spatial frequency is listed as the sagittal curve S2 and the meridional curve T2 of the field of view, and the MTF of 42lp / mm spatial frequency is listed as the sagittal curve S3 and the meridional curve T3 of the field of view. Fig.23 It can be seen that within the entire field of view, the MTF is greater than 0.45, and the imaging quality of the far-infrared optical system 100 is excellent.

[0193] See also Fig.24 , Fig.241 shows a field curvature diagram of the far-infrared optical system 100 provided in Example 5, Fig.24 The central horizontal axis is the field curvature, which is in millimeters; Fig.24 The vertical axis is the Y-axis field of view, and its unit is degree. Fig.24 S1 is the field curvature of far-infrared light with a wavelength of 8 microns in the sagittal direction, and T1 is the field curvature of far-infrared light with a wavelength of 8 microns in the meridional direction; S2 is the field curvature of far-infrared light with a wavelength of 10 microns in the sagittal direction, and T2 is the field curvature of far-infrared light with a wavelength of 10 microns in the meridional direction; S3 is the field curvature of far-infrared light with a wavelength of 12 microns in the sagittal direction, and T3 is the field curvature of far-infrared light with a wavelength of 12 microns in the meridional direction. Fig.24 It can be seen that the maximum field curvature of the far-infrared optical system 100 in the sagittal direction is 0.0400 mm, and the maximum field curvature of the far-infrared optical system 100 in the meridional direction is 0.1605 mm, which meets the requirements for field curvature in the excellent imaging quality standard.

[0194] See also Fig.25 , Fig.25 The distortion diagram of the far-infrared optical system 100 provided in Example 5 under far-infrared light with wavelengths of 8 microns, 10 microns and 12 microns is shown. Fig.25 The horizontal axis is distortion, and its unit is percentage; Fig.25 The vertical axis is the Y-axis field of view, and its unit is degree. Fig.25 The distortion curves of far-infrared light with medium wavelengths of 8 microns, 10 microns, and 12 microns are almost overlapping, so this embodiment does not distinguish between the three curves. Fig.25 It can be seen that within the full field of view, the maximum distortion of the far-infrared optical system 100 is 0.85%, which is relatively small and meets the distortion requirement of the excellent imaging quality standard.

[0195] After summarizing the various parameters of the far-infrared optical system 100 provided by the above five embodiments, the following Table 6 is obtained. Table 6 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.

[0196] Table 6. Parameters of the far-infrared optical system 100 provided in various embodiments

[0197]

[0198]

[0199] The present application also provides a far-infrared optical lens, which includes an imaging detector (not shown) and the above-mentioned far-infrared optical system 100. The specific structure of the far-infrared optical system 100 can be found above, and its specific structure will not be repeated here. The imaging detector is arranged on the image plane 70 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).

[0200] Those skilled in the art will readily appreciate other embodiments of the present application after considering the specification and practicing the invention 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, in order from the object side to the image side along the optical axis: a first aspheric lens, a super lens and a second aspheric lens; the optical power of the first aspheric lens is positive, the object side surface of the first aspheric lens is convex to the object side, and the image side surface of the first aspheric lens is convex to the object side; the optical power of the super lens is positive; the optical power of the second aspheric lens is positive, the object side surface of the second aspheric lens is convex to the object side, and the image side surface of the second aspheric lens is convex to the object side; The far-infrared optical system satisfies: Φ a1 +Φ m <Φ a2 , Φ m ≤Φ a1 , where the Φ a1 is the focal length of the first aspheric lens, the Φ m is the optical power of the metalens, the Φ a2 is the optical power of the second aspherical lens.

2. The far-infrared optical system according to claim 1, characterized in that: The far-infrared optical system meets the following requirements: Wherein, f is the effective focal length of the far-infrared optical system, and f a1 is the focal length of the first aspheric lens, and the f a2 is the focal length of the second aspheric lens, the f m is the focal length of the metalens.

3. The far-infrared optical system according to claim 1, characterized in that: The far-infrared optical system meets the following requirements: Among them, the f a1 is the focal length of the first aspheric lens, and the f a2 is the focal length of the second aspheric lens, D1 is the maximum effective diameter of the first aspheric lens, and D2 is the maximum effective diameter of the second aspheric lens.

4. The far-infrared optical system according to claim 1, characterized in that: The far-infrared optical system meets the following requirements: Among them, the L 13 is the distance between the image side surface of the first aspheric lens and the object side surface of the second aspheric lens on the optical axis, the TTL is the total optical length of the far-infrared optical system, and the FOV is the maximum field of view angle of the far-infrared optical system.

5. The far-infrared optical system according to claim 1, characterized in that: The far-infrared optical system meets the following requirements: Wherein, the Sag1 is the sag height of the object side surface of the first aspheric lens at the maximum effective diameter; and the R1 is the radius of curvature of the object side surface of the first aspheric lens.

6. The far-infrared optical system according to claim 1, characterized in that: The far-infrared optical system meets the following requirements: D1 is the maximum effective diameter of the first aspheric lens, m is the maximum effective diameter of the super lens, and D2 is the maximum effective diameter of the second aspheric lens.

7. The far-infrared optical system according to claim 1, characterized in that: The far-infrared optical system meets the following requirements: Among them, f is the effective focal length of the far-infrared optical system, n is the refractive index of the first aspheric lens, FNO is the aperture number of the far-infrared optical system, and R1 is the curvature radius of the object side of the first aspheric lens.

8. The far-infrared optical system according to claim 1, characterized in that: The far-infrared optical system meets the following requirements: Wherein, D1 is the maximum effective diameter of the first aspheric lens, D2 is the maximum effective diameter of the second aspheric lens, and L 13 is the distance between the image side surface of the first aspheric lens and the object side surface of the second aspheric lens on the optical axis, and L B is the distance between the image side surface of the second aspherical lens and the image plane of the far-infrared optical system on the optical axis, and f is the effective focal length of the far-infrared optical system.

9. The far-infrared optical system according to any one of claims 1 to 8, characterized in that: The far-infrared optical system further includes an aperture, which is disposed on the object side of the first aspheric lens; or, the aperture is disposed between any two adjacent lenses.

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

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