Infrared optical system and infrared optical lens

Abstract

The utility model discloses an infrared optical system and an infrared optical lens. The infrared optical system sequentially comprises a first aspheric lens with negative focal power, a second aspheric lens with positive focal power, a super lens with positive focal power and a third aspheric lens with positive focal power from an object side to an image side. The surfaces, close to the object side and away from the object side, of the first aspheric lens protrude towards the object side. The surface, close to the object side, of the second aspheric lens protrudes towards the object side, and the surface, away from the object side, of the second aspheric lens protrudes towards the object side or the image side. The surfaces, close to the object side and away from the object side, of the third aspheric lens protrude towards the image side. The infrared optical system provided by the utility model has relatively high resolution and can be matched with an imaging detector with relatively high resolution for use. The infrared optical system has a large imaging range, can obtain more imaging information, and can distinguish more imaging details at the same time. Meanwhile, the infrared optical system also has the advantage of relatively low cost.

Description

Technical Field

[0001] The present application relates to the field of lenses, and in particular to an infrared optical system and an infrared optical lens. Background Art

[0002] The lens is generally composed of two parts: the optical system and the structural parts. The infrared lens is also called the infrared thermal imaging lens, and its working band is far infrared, that is, the imaging lens with a working wavelength of 8-12μm. The infrared lens can make up for the defects of the visible light imaging lens, and can replace the visible light imaging in fog, haze, rain, snow, night and other environments. It is widely used in security, vehicle-mounted, military and other fields.

[0003] With the continuous development of image sensor technology, the demand for high-pixel and high-resolution imaging in society and production is increasing. In the field of far-infrared imaging, with the advancement of technology, the resolution of image detectors has increased from the initial 50,000 to 300,000, and now even image sensors with one million pixels have been launched. The pixel size has also gradually decreased from the initial 35μm to 17μm and 12μm. As the pixel size becomes smaller and smaller, the imaging resolution of the matching lens also needs to be improved. Utility Model Content

[0004] In view of the above technical problems, the embodiments of the present application provide an infrared optical system and an infrared optical lens, which aim to solve the problem of low resolution of infrared optical lenses in the prior art.

[0005] According to one aspect of an embodiment of the present application, an infrared optical system is disclosed, which includes, in sequence from the object side to the image side along the optical axis: a first aspheric lens, a second aspheric lens, a super lens and a third aspheric lens; the first aspheric lens has a negative optical focal length, the first aspheric lens is a germanium lens, the surface of the first aspheric lens close to the object side is convex toward the object side, and the surface of the first aspheric lens away from the object side is convex toward the object side; the second aspheric lens has a positive optical focal length, the surface of the second aspheric lens close to the object side is convex toward the object side, and the surface of the second aspheric lens away from the object side is convex toward the object side or the image side; the super lens has a positive optical focal length; the third aspheric lens has a positive optical focal length, the surface of the third aspheric lens close to the object side is convex toward the image side, and the surface of the third aspheric lens away from the object side is convex toward the image side.

[0006] In some embodiments, the infrared optical system satisfies: Wherein, fno is the relative aperture of the infrared optical system, and R 1 is the radius of curvature of the surface of the first aspheric lens close to the object side, and the R S1is the effective radius of the surface of the first aspheric lens close to the object side; 9 is the radius of curvature of the surface of the third aspheric lens close to the image side, and the R S9 is the effective radius of the surface of the third aspheric lens close to the image side; the TTL is the total optical length of the infrared optical system, and the BFL is the back focal length of the infrared optical system.

[0007] In some embodiments, the infrared optical system satisfies: Among them, the R S1 is the effective radius of the surface of the first aspheric lens close to the object side, and the R S2 is the effective radius of the surface of the first aspheric lens close to the image side; the surface of the first aspheric lens close to the object side is the first surface, and the SAG 11 is the intersection of the first surface and the optical axis, and the distance from the vertex of the effective radius of the first surface on the optical axis; the surface of the first aspheric lens close to the object side is the second surface, and the SAG 12 is the distance between the intersection of the second surface and the optical axis and the vertex of the effective radius of the second surface on the optical axis.

[0008] In some embodiments, the infrared optical system satisfies: Among them, f is the effective focal length of the infrared optical system, Semi_FOV is half of the maximum field of view angle of the incident light of the infrared optical system, and Semi_ImgH is half of the maximum image height of the infrared optical system.

[0009] In some embodiments, the infrared optical system satisfies: Among them, the is the maximum value of the phase difference provided by the metalens, and the R M is the optical effective radius of the metalens.

[0010] In some embodiments, the infrared optical system satisfies: Among them, the R 8 is the radius of curvature of the surface of the third aspheric lens close to the object side, and the R 9 is the curvature radius of the surface of the third aspheric lens close to the image side, and the C S8 is the center thickness of the third aspheric lens, and the E S8 is the edge thickness of the third aspheric lens.

[0011] In some embodiments, the infrared optical system satisfies: Among them, the C S3is the center thickness of the second aspheric lens, the C S45 is the distance between the surface of the second aspheric lens close to the image side and the surface of the super lens close to the object side on the optical axis; S8 is the center thickness of the third aspheric lens, and the C S67 is the distance between the surface of the superlens close to the object side and the third aspheric lens on the optical axis.

[0012] In some embodiments, the infrared optical system satisfies: Among them, the R 4 is the radius of curvature of the surface of the second aspheric lens close to the image side, and the R 8 is the radius of curvature of the surface of the third aspheric lens close to the object side.

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

[0014] In some embodiments, the infrared optical system satisfies: Wherein, the BFL is the back focal length of the infrared optical system, and f is the effective focal length of the infrared optical system.

[0015] In some embodiments, the infrared optical system satisfies: Wherein, the BFL is the back focal length of the infrared optical system, and the TTL is the total optical length of the infrared optical system.

[0016] In some embodiments, the infrared optical system satisfies: Among them, the f 1 is the focal length of the first aspheric lens, and f is the effective focal length of the infrared optical system.

[0017] In some embodiments, the infrared optical system satisfies: Among them, the f 2 is the focal length of the second aspheric lens, and f is the effective focal length of the infrared optical system.

[0018] In some embodiments, the infrared optical system satisfies: Among them, the f M is the focal length of the superlens, and f is the effective focal length of the infrared optical system.

[0019] In some embodiments, the infrared optical system satisfies: Among them, the f 3is the focal length of the third aspheric lens, and f is the effective focal length of the infrared optical system.

[0020] A second aspect of an embodiment of the present application provides an infrared optical lens, comprising: an imaging detector and an infrared optical system as described in any one of the above items; the imaging detector is arranged on the image plane of the infrared optical system.

[0021] In some embodiments, the infrared optical lens further comprises a lens barrel, the lens barrel is provided with a mounting through hole, and the mounting through hole comprises a first hole segment, a second hole segment, a third hole segment and a fourth hole segment in sequence from the object side to the image side along the optical axis;

[0022] The diameter of the first hole segment is greater than the diameter of the second hole segment, and the first aspheric lens is accommodated in a side of the first hole segment close to the second hole segment; the diameter of the second hole segment is greater than the diameter of the third hole segment, and the second aspheric lens and the super lens are both accommodated in the second hole segment, and the super lens is located in a side of the second hole segment close to the third hole segment; the diameter of the third hole segment is greater than the diameter of the fourth hole segment, and the third aspheric lens is accommodated in a side of the third hole segment close to the fourth hole segment.

[0023] In some embodiments, the infrared optical lens further includes a pressure ring, a first spacer ring, and a second spacer ring;

[0024] The pressure ring is accommodated in the first hole section, and the pressure ring abuts against the surface of the first aspheric lens close to the object side; the first spacer is accommodated in the second hole section, one side of the first spacer abuts against the surface of the first aspheric lens close to the image side, and the other side of the first spacer abuts against the surface of the second aspheric lens close to the object side; one side of the second spacer abuts against the surface of the second aspheric lens close to the image side, and the other side of the second spacer abuts against the surface of the super lens close to the object side; the super lens abuts against the third aspheric lens.

[0025] The infrared optical system provided by the present application includes a first aspheric lens, a second aspheric lens, a super lens and a third aspheric lens from the object side to the image side in sequence; the first aspheric lens has a negative optical focal length, the first aspheric lens is a germanium lens, the surface of the first aspheric lens close to the object side is convex to the object side, and the surface of the first aspheric lens away from the object side is convex to the object side; the second aspheric lens has a positive optical focal length, the surface of the second aspheric lens close to the object side is convex to the object side, and the surface of the second aspheric lens away from the object side is convex to the object side or the image side; the super lens has a positive optical focal length; the third aspheric lens has a positive optical focal length, the surface of the third aspheric lens close to the object side is convex to the image side, and the surface of the third aspheric lens away from the object side is convex to the image side. The infrared optical system provided by the present application using a three-piece aspheric lens plus a super lens structure has a high resolution and can match an imaging detector with a high resolution, for example, an imaging detector with a resolution of 1280×1024 and a pixel size of 8 microns. The infrared optical system has a horizontal field of view of 120°, has a large imaging range, can obtain more imaging information, and can distinguish more imaging details. At the same time, the infrared optical system uses only one germanium lens, and the infrared optical system also uses a super lens, which is produced by semiconductor technology and has a low single-chip cost when mass-produced. Therefore, the infrared optical system provided by the present application also has the advantage of relatively low cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] 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.

[0027] Figure 1 A schematic diagram of the architecture layout of an infrared optical system in an embodiment of the present application is shown.

[0028] Figure 2 The MTF field of view curve diagram of the infrared optical system in one embodiment of the present application is shown.

[0029] Figure 3 A field curvature curve diagram of an infrared optical system in an embodiment of the present application is shown.

[0030] Figure 4 A distortion grid diagram of an infrared optical system in one embodiment of the present application is shown.

[0031] Figure 5 A spot diagram of an infrared optical system in an embodiment of the present application is shown.

[0032] Figure 6 A relative illumination curve diagram of an infrared optical system in an embodiment of the present application is shown.

[0033] Figure 7 A phase curve diagram of a metalens of an infrared optical system in an embodiment of the present application is shown.

[0034] Figure 8 A schematic diagram of the architecture layout of an infrared optical system in an embodiment of the present application is shown.

[0035] Fig. 9 The MTF field of view curve diagram of the infrared optical system in one embodiment of the present application is shown.

[0036] Fig.10 A field curvature curve diagram of an infrared optical system in an embodiment of the present application is shown.

[0037] Fig.11 A distortion grid diagram of an infrared optical system in one embodiment of the present application is shown.

[0038] Fig.12 A spot diagram of an infrared optical system in an embodiment of the present application is shown.

[0039] Fig.13 A relative illumination curve diagram of an infrared optical system in an embodiment of the present application is shown.

[0040] Fig.14 A phase curve diagram of a metalens of an infrared optical system in an embodiment of the present application is shown.

[0041] Fig.15 A schematic diagram of the architecture layout of an infrared optical system in an embodiment of the present application is shown.

[0042] Fig.16 The MTF field of view curve diagram of the infrared optical system in one embodiment of the present application is shown.

[0043] Fig.17 A field curvature curve diagram of an infrared optical system in an embodiment of the present application is shown.

[0044] Fig.18 A distortion grid diagram of an infrared optical system in one embodiment of the present application is shown.

[0045] Fig.19 A spot diagram of an infrared optical system in an embodiment of the present application is shown.

[0046] Fig. 20 A relative illumination curve diagram of an infrared optical system in an embodiment of the present application is shown.

[0047] Fig.21 A phase curve diagram of a metalens of an infrared optical system in an embodiment of the present application is shown.

[0048] Fig. 22 A schematic diagram of the architecture layout of an infrared optical system in an embodiment of the present application is shown.

[0049] Fig.23The MTF field of view curve diagram of the infrared optical system in one embodiment of the present application is shown.

[0050] Fig.24 A field curvature curve diagram of an infrared optical system in an embodiment of the present application is shown.

[0051] Fig.25 A distortion grid diagram of an infrared optical system in one embodiment of the present application is shown.

[0052] Fig.26 A spot diagram of an infrared optical system in an embodiment of the present application is shown.

[0053] Fig. 27 A relative illumination curve diagram of an infrared optical system in an embodiment of the present application is shown.

[0054] Fig.28 A phase curve diagram of a metalens of an infrared optical system in an embodiment of the present application is shown.

[0055] Fig.29 A schematic diagram of the structure of an infrared optical lens in an embodiment of the present application is shown.

[0056] Reference numerals

[0057] 100. Infrared optical system;

[0058] 1. The first aspheric lens;

[0059] 2. A second aspheric lens;

[0060] 3. Super lens; 31. Micro-nano structure;

[0061] 4. The third aspheric lens;

[0062] 5. Aperture;

[0063] 6. Protective parts;

[0064] 7. Window materials;

[0065] A, object plane; B, image plane; S, optical axis;

[0066] 200, lens barrel; 2001, mounting through hole; 2001a, first hole section; 2001b, second hole section;

[0067] 2001c, third hole section; 2001d, fourth hole section;

[0068] 300, press circle;

[0069] 400, first spacer;

[0070] 500, Second Spacer

[0071] 1000. Infrared optical lens. DETAILED DESCRIPTION

[0072] 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.

[0073] 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 unclear.

[0074] The present application provides an infrared optical system 100. The prior art closest to the specifications to be implemented by the present application is Chinese patent CN115079378A, which discloses a short-focus, low-distortion, athermal infrared lens. The effective focal length of the lens is close to the effective focal length of the infrared optical system provided by the present application, but the lens can only match low-resolution detectors (such as conventional 384×288, 17 micron pixel size detectors), which cannot meet the requirements of high-specification detectors for clear imaging, and is not conducive to improving the image quality of the lens. In addition, the lens includes a germanium lens and a zinc sulfide lens, resulting in a high cost of the lens.

[0075] See also Figure 1 , Figure 1 FIG. 1 shows a schematic diagram of the structure layout of an 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 left side of the leftmost lens is the object side, and the object plane A is located on the object side. The right side of the rightmost lens is the image side, and the image plane B is located on the image side. Therefore, the direction from the object plane A to the image plane B along the optical axis S is consistent with the direction from the object side to the image side along the optical axis S.

[0076] The infrared optical system 100 includes a first aspheric lens 1, a second aspheric lens 2, a super lens 3 and a third aspheric lens 4. The first aspheric lens 1, the second aspheric lens 2, the super lens 3 and the third aspheric lens 4 are arranged in sequence along the optical axis S from the object plane A to the image plane B.

[0077] The first aspheric lens 1 is a meniscus lens, has negative optical power, and is a germanium lens. The surface of the first aspheric lens 1 close to the object plane A is convex to the object plane A, and the surface of the first aspheric lens 1 far from the object plane A is convex to the object plane A.

[0078] The second aspheric lens 2 has positive focal power, the surface of the second aspheric lens 2 close to the object plane A is convex toward the object plane A, and the surface of the second aspheric lens 2 away from the object plane A is convex toward the object plane A or the image plane B, that is, the second aspheric lens 2 is a meniscus lens or a double convex lens.

[0079] The superlens 3 includes a substrate and a superstructure unit located on the surface of the substrate, and a micro-nanostructure 31 is provided at the vertex and / or center of the superstructure unit. The filling material between the micro-nanostructures 31 is air or other materials that are transparent in the working band. The micro-nanostructure 31 can be provided on the surface of the substrate facing the object side, or on the surface of the substrate facing the image side. The micro-nanostructure 31 can be provided with one layer, two layers or more than three layers. According to the phase modulation method adopted, the various parameters of the micro-nanostructure 31 can be adaptively configured using a matching phase modulation formula, so that the superlens 3 can achieve corresponding optical performance.

[0080] The superlens 3 has positive optical power and provides different focal lengths at different wavelengths. Therefore, the superlens 3 cooperates with other lenses to converge the focus of each single wavelength light image plane at the same position to achieve the achromatic function.

[0081] The third aspheric lens 4 is a meniscus lens and has positive optical power. The surface of the third aspheric lens 4 close to the object surface A is convex toward the image surface B, and the surface of the third aspheric lens 4 far from the object surface A is convex toward the image surface B.

[0082] The present application provides an infrared optical system 100 using three aspheric lenses plus a super lens 3 structure, which can be adapted to high-resolution and small-pixel large-image imaging detectors, for example, imaging detectors with a resolution of 1280×1024 and a pixel size of 8 microns. It should be noted that the infrared optical system 100 is not only adapted to imaging detectors with a resolution of 1280×1024 and a pixel size of 8 microns. Here, only an exemplary imaging detector specification that an infrared optical system 100 can adapt to is provided. The infrared optical system 100 has a horizontal field of view of 120°, has a large imaging range, can obtain more imaging information, and can distinguish more imaging details, and has better imaging quality. At the same time, the infrared optical system 100 uses only one germanium lens, and the infrared optical system 100 also uses a super lens 3. The super lens 3 is produced by semiconductor technology, and its single-chip cost is low when it is mass-produced. Therefore, the infrared optical system 100 provided in the present application also has the advantage of relatively low cost.

[0083] In some embodiments, the infrared optical system 100 satisfies conditional formula (1):

[0084]

[0085] Wherein, fno is the relative aperture of the infrared optical system 100, which is also called the aperture number, and is the ratio of the focal length of the infrared optical system 100 to the entrance pupil diameter. 1 R is the radius of curvature of the surface of the first aspheric lens 1 close to the object surface A, and its unit is length unit. 9 R is the curvature radius of the surface of the third aspheric lens 4 close to the image plane B, and its unit is a length unit. S1 is the effective radius of the surface of the first aspheric lens 1 close to the object surface A, and its unit is the length unit. For the effective radius, the distance from the edge position that the incident light can reach on the lens to the center of the lens is the effective radius, so R S1 R is the distance from the edge of the first aspheric lens 1 close to the object plane A that the incident light can reach to the center of the first aspheric lens 1. S9 is the effective radius of the surface of the third aspheric lens 4 close to the image surface B, that is, R S9 R is the distance from the edge of the third aspheric lens 4 close to the image plane B to the center of the third aspheric lens 4. S9 The unit is the length unit. 1 , R 9 , R S1 and R S9 have the same dimension, for example, millimeters.

[0086] TTL (Total Track Length, abbreviated as TTL, total optical length) is the total optical length of the infrared optical system 100. The total optical length refers to the distance from the center of the front surface of the first lens in the optical system to the imaging plane, and its unit is millimeter. In the infrared optical system 100 provided in the present application, the total optical length is the distance from the center of the surface of the first aspheric lens 1 close to the object plane A to the image plane. BFL (Back focal length, abbreviated as BFL, back focal length) is the distance from the vertex of the last optical surface of the optical system to the image plane B, and its unit is millimeter. In the infrared optical system 100 provided in the present application, BFL is the distance from the vertex of the surface of the third aspheric lens 4 close to the image plane B to the image plane B.

[0087] The infrared optical system 100 satisfies the conditional expression (1), so that the infrared optical system 100 can meet the requirements of large aperture and miniaturization while realizing the imaging requirements of high resolution, large field of view and large image surface.

[0088] In some embodiments, the infrared optical system 100 satisfies conditional formula (2):

[0089]

[0090] Among them, R S1 R is the effective radius of the surface of the first aspheric lens 1 close to the object surface A, and its unit is length unit. S2 is the effective radius of the surface of the first aspheric lens 1 close to the image plane B, and its unit is the length unit. The definition of the effective radius can be referred to above and will not be elaborated in this article. The surface of the first aspheric lens 1 close to the object plane A is the first surface, SAG 11 is the intersection of the first surface and the optical axis S, and the distance from the vertex of the effective radius of the first surface on the optical axis S, and its unit is the unit of length. The surface of the first aspheric lens 1 close to the object surface A is the second surface, SAG 12 is the distance between the intersection of the second surface and the optical axis S and the vertex of the effective radius of the second surface on the optical axis S, and its unit is the unit of length. S1 , R S2 、SAG 11 、SAG 12 have the same dimension, for example, millimeters.

[0091] The infrared optical system 100 satisfies the conditional formula (2) and can effectively control the on-axis spherical aberration and off-axis coma caused by the first aspheric lens 1. At the same time, the surface shape of the first aspheric lens 1 is reasonably controlled, reducing its processing difficulty. And the strength of the first aspheric lens 1 is increased, making it less fragile. In addition, satisfying the conditional formula (2) also ensures that the volume of the first aspheric lens 1 does not increase while ensuring the increase of the amount of light entering the infrared optical system 100, which can effectively reduce the consumables of the first aspheric lens 1, reduce the waste generated when the first aspheric lens 1 is polished, and reduce costs.

[0092] In some embodiments, the infrared optical system 100 satisfies conditional formula (3):

[0093]

[0094] Wherein, f is the effective focal length of the infrared optical system 100, and its unit is a length unit. Semi_FOV is half of the maximum field angle of the incident light of the infrared optical system 100, and its unit is a degree. Semi_ImgH is half of the maximum image height of the infrared optical system 100, and its unit is a length unit. Semi_ImgH and f have the same dimension, for example, both are millimeters. Satisfying conditional formula (3) can ensure that the infrared optical system 100 has a large field angle and a large imaging surface height, so that the infrared optical system 100 has a large field of view and a large image height.

[0095] In some embodiments, the infrared optical system 100 satisfies conditional formula (4):

[0096]

[0097] in, is the maximum value of the phase difference provided by the super lens 3, and its unit is radian (rad). M is the optical effective radius of the metalens 3, in millimeters. The definition of the optical effective radius is referred to above and will not be elaborated in this article.

[0098] Conditional equation (4) reflects the average phase gradient of the superlens 3. Satisfying conditional equation (4) is beneficial for the superlens 3 to correct the dispersion generated by the infrared optical system 100, while the average phase gradient will not be too large to exceed the phase modulation capability of the superlens 3 for light.

[0099] In some embodiments, the infrared optical system 100 satisfies conditional equation (5):

[0100]

[0101] Among them, R 8R is the radius of curvature of the surface of the third aspheric lens 4 close to the object surface A, and its unit is length unit. 9 C is the curvature radius of the surface of the third aspherical lens 4 close to the image plane B, and its unit is a length unit. S8 is the center thickness of the third aspheric lens 4, which is also the thickness on the optical axis S, that is, C S8 is the thickness of the third aspheric lens 4 on the optical axis S, C S8 The unit of is length unit. S8 is the edge thickness of the third aspherical lens 4, that is, E S8 is the thickness of the third aspheric lens 4 at the farthest point from the optical axis S, E S8 The unit is the length unit. 8 , R 9 , C S8 and E S8 have the same dimension, for example, millimeters.

[0102] Conditional formula (5) constrains the surface parameters and thickness parameters of the third aspherical lens 4, which can effectively limit the field curvature generated by different fields of view of the infrared optical system 100 and reduce off-axis aberrations. In addition, it also effectively controls the outgoing light of the infrared optical system 100 and improves the relative illumination of the optical system.

[0103] In some embodiments, the infrared optical system 100 satisfies conditional equation (6):

[0104]

[0105] Among them, C S3 is the center thickness of the second aspheric lens 2, that is, C S3 is the thickness of the second aspherical lens 2 on the optical axis S, and its unit is a length unit. S45 C is the distance between the surface of the second aspherical lens 2 close to the image plane B and the surface of the super lens 3 close to the object plane A on the optical axis S, and its unit is the unit of length. S8 is the center thickness of the third aspheric lens 4, that is, C S8 is the thickness of the third aspherical lens 4 on the optical axis S, and its unit is a length unit. S67 C is the distance between the surface of the super lens 3 close to the object plane A and the third aspheric lens 4 on the optical axis S, and its unit is the length unit. S3 , C S45 , C S8 and C S67 have the same dimension, for example, millimeters.

[0106] Satisfying conditional formula (6) can achieve complementary astigmatism and correction of on-axis chromatic aberration and off-axis chromatic aberration between the second aspheric lens 2, the metalens 3 and the third aspheric lens 4, thereby reducing off-axis aberration and chromatic aberration of the infrared optical system 100 and improving imaging quality.

[0107] In some embodiments, the infrared optical system 100 satisfies conditional equation (7):

[0108]

[0109] Among them, R 4 R is the radius of curvature of the surface of the second aspheric lens 2 close to the image plane B, and its unit is a length unit. 8 R is the radius of curvature of the surface of the third aspheric lens 4 close to the object surface A, and its unit is length unit. 8 With R 4 have the same dimension, for example, millimeters.

[0110] Satisfying the conditional formula (7) can effectively reduce the reflection of light between the surface of the second aspheric lens 2 close to the image plane B and the surface of the third aspheric lens 4 close to the object plane A, thereby reducing the probability of ghost images and stray light, and improving the imaging quality.

[0111] In some embodiments, the infrared optical system 100 satisfies conditional equation (8):

[0112]

[0113] Wherein, f is the effective focal length of the infrared optical system 100, and its unit is a length unit. D is the entrance pupil diameter of the infrared optical system 100, and its unit is a length unit. D and f have the same dimension, for example, both are millimeters.

[0114] Conditional formula (8) constrains the relative aperture of the optical system. Compared with the common optical system with a relative aperture of 1 on the market, the relative aperture of the infrared optical system 100 provided in the present application is 0.9 to 0.93, which effectively increases the amount of light entering the infrared optical system 100, so that the lens corresponding to the infrared optical system 100 has a higher amount of light entering and a higher light energy utilization rate.

[0115] In some embodiments, the infrared optical system 100 satisfies conditional equation (9):

[0116]

[0117] Wherein, BFL is the back focal length of the infrared optical system 100, and its unit is a length unit. f is the effective focal length of the infrared optical system 100, and its unit is a length unit. f and BFL have the same dimension, for example, both are millimeters.

[0118] The infrared optical system 100 satisfies conditional formula (9) and can effectively control the optical back focus, so that the infrared optical system 100 can maintain the optical back focus of the infrared optical system 100 greater than 8 mm while maintaining the field of view unchanged, thereby reducing the collision risk when the infrared optical system 100 is installed.

[0119] In some embodiments, the infrared optical system 100 satisfies conditional formula (10):

[0120]

[0121] Wherein, BFL is the back focal length of the infrared optical system 100, and its unit is a length unit. TTL is the total optical length of the infrared optical system 100, and its unit is a length unit. TTL and BFL have the same dimension, for example, both are millimeters. Conditional formula (10) constrains the proportion of the optical back focal length in the total optical length. Since this ratio is small, the miniaturization of the infrared optical system 100 can be achieved.

[0122] In some embodiments, the infrared optical system 100 satisfies condition 1:

[0123]

[0124] Among them, f 1 is the focal length of the first aspherical lens 1, and its unit is the length unit. f is the effective focal length of the infrared optical system 100, and its unit is the length unit. 1 have the same dimension, for example, millimeters.

[0125] Meeting condition 1 can make the field angle of external light absorbed by the infrared optical system 100 larger, realize the wide angle of the infrared optical system 100, and make the light pass smoothly through the infrared optical system 100 and form an image on the image plane. The compression ratio of the light of the infrared optical system 100 is improved, and the utilization rate of light energy is improved.

[0126] In some embodiments, the infrared optical system 100 satisfies condition 2:

[0127]

[0128] Among them, f 2 is the focal length of the second aspherical lens 2, and its unit is the length unit. f is the effective focal length of the infrared optical system 100, and its unit is the length unit. 2 have the same dimension, for example, millimeters.

[0129] When the infrared optical system 100 meets the second condition, several on-axis and off-axis primary aberrations generated by the infrared optical system 100 can be effectively corrected, the sensitivity of the infrared optical system 100 can be reduced, and the assembly yield of the infrared optical system 100 can be improved.

[0130] In some embodiments, the infrared optical system 100 satisfies condition three:

[0131]

[0132] Among them, f M is the effective focal length of the super lens 3, and its unit is the length unit. f is the effective focal length of the infrared optical system 100, and its unit is the length unit. M have the same dimension, for example, millimeters.

[0133] Meeting condition three is conducive to reducing the sensitivity of the superlens 3 to coaxiality and tilt, reducing the difficulty of assembling the superlens 3, relaxing the structural tolerance of the superlens 3, and improving the usability of the superlens 3.

[0134] In some embodiments, the infrared optical system 100 satisfies condition 4:

[0135]

[0136] Among them, f 3 is the effective focal length of the third aspherical lens 4, and its unit is a length unit. f is the effective focal length of the infrared optical system 100, and its unit is a length unit. 3 have the same dimension, for example, millimeters.

[0137] Meeting condition 4 is conducive to reasonably distributing the optical power of the third aspheric lens 4 , maintaining the symmetry of the position of the second aspheric lens 2 relative to the aperture 5 , reducing the sensitivity of the infrared optical system 100 , and improving the assembly yield of the infrared optical system 100 .

[0138] In some embodiments, the material of the second aspherical lens 2 and the third aspherical lens 4 is chalcogenide glass.

[0139] In some embodiments, the second aspheric lens 2 is a biconvex lens, and a surface of the second aspheric lens 2 close to the image plane B has an inflection point.

[0140] In some embodiments, the infrared optical system 100 further includes an aperture 5, which is arranged corresponding to the superlens 3, and is used to limit the amount of light entering, thereby affecting the imaging quality and performance of the infrared optical system 100.

[0141] In some embodiments, the aperture 5 is disposed on a surface of the superlens 3 close to the object plane A.

[0142] In some embodiments, the aperture 5 is disposed between the second aspherical lens 2 and the super lens 3 .

[0143] In some embodiments, the infrared optical system 100 further includes a protective member 6, which is located along the optical axis S on the side of the third aspheric lens 4 away from the super lens 3. The protective member 6 can transmit light and is used to isolate the external environment, thereby reducing the probability of damage to the devices inside it.

[0144] The protective member 6 may be in the form of protective glass, but the material of the protective member 6 is not limited to silicon. For example, the material of the protective member 6 may also be germanium.

[0145] In some embodiments, the infrared optical system 100 further includes a window material 7, which is located on the side of the protective member 6 away from the third aspheric lens 4 along the optical axis S. The window material 7 can be used to isolate the external environment, protect the internal components, and has a high transmittance to light of a specific wavelength or wavelength range. In the present application, the window material 7 has a high transmittance to far-infrared light and acts as a window. The window material 7 has various forms and can be single crystal, polycrystalline, glass or film.

[0146] The present application exemplarily provides four infrared optical systems 100 that meet the use requirements in four embodiments. Next, the infrared optical systems 100 provided by the various embodiments of the present application are described in detail. Table 1 shows the optical specifications achieved by the following four embodiments.

[0147] Table 1. Optical specifications achieved by the following four embodiments

[0148] Working band 8μm~12μm Resolution 1280×1024@8μm Fno. <0.93 Field of view (H×D) ≥120°×160° TTL ≤50mm BFL ≥8.5mm RI ≥70％ Optical distortion |<50％|

[0149] Example 1

[0150] Figure 1 The schematic diagram of the architecture layout of the infrared optical system 100 provided in Example 1 is shown. In Example 1, the effective focal length of the infrared optical system 100 is 4.63 mm, and the infrared optical system 100 includes, along the optical axis S from the object plane A to the image plane B, a first aspheric lens 1, a second aspheric lens 2, an aperture 5, a super lens 3, a third aspheric lens 4, a protective member 6, and a window material 7. Starting from the object plane, along the optical axis S from the object plane A to the image plane B, the surfaces in the infrared optical system 100 are numbered, and the parameters of the surfaces are summarized to obtain the following Table 2.

[0151] Table 2. Parameters of various surfaces in the infrared optical system 100 provided in Example 1

[0152]

[0153]

[0154] For each surface in Table 2, surface S0 is the object plane. Surface S1 is the surface of the first aspheric lens 1 close to the object plane A, and surface S2 is the surface of the first aspheric lens 1 away from the object plane A. Surface S3 is the surface of the second aspheric lens 2 close to the object plane A, and surface S4 is the surface of the second aspheric lens 2 away from the object plane A. Surface S5 is the aperture 5. Surface S6 is the surface of the superlens 3 close to the object plane A. Since the micro-nano structure is provided on the surface of the superlens 3 close to the object plane A, it is recorded as the supersurface 31, and surface S7 is the surface of the superlens 3 away from the object plane A. Surface S8 is the surface of the third aspheric lens 4 close to the object plane A, and surface S9 is the surface of the third aspheric lens 4 away from the object plane A. Surface S10 is the surface of the protective member 6 close to the object plane A, and surface S11 is the surface of the protective member 6 away from the object plane A. Surface S12 is the surface of the window material 7 close to the object plane A, and surface S13 is the surface of the window material 7 away from the object plane A. Surface S14 is an image surface.

[0155] As can be seen from Table 2, surface S0 is a plane, the distance between surface S0 and surface S1 is uncertain, and the material between surface S0 and surface S1 is air. Surface S1 is an aspherical surface, the radius of curvature of surface S1 is 15.425 mm, the distance between surface S1 and surface S2 is 4.163 mm, and the material between surface S1 and surface S2 is germanium. Surface S2 is an aspherical surface, the radius of curvature of surface S2 is 8.322 mm, the distance between surface S2 and surface S3 is 13.650 mm, and the material between surface S2 and surface S3 is air. Surface S3 is an aspherical surface, the radius of curvature of surface S3 is 21.876 mm, the distance between surface S3 and surface S4 is 6.036 mm, and the material between surface S3 and surface S4 is chalcogenide glass. Surface S4 is an aspherical surface, the radius of curvature of surface S4 is 142.767 mm, the distance between surface S4 and surface S5 is 2.906 mm, and the material between surface S4 and surface S5 is air. Surface S5 is a plane, the distance between surface S5 and surface S6 is 0.925 mm, and the material between surface S5 and surface S6 is air. Surface S6 is a super surface 31, which is a plane. The distance between surface S6 and surface S7 is 0.300 mm, and the material between surface S6 and surface S7 is silicon. Surface S7 is a plane, the distance between surface S7 and surface S8 is 1.510 mm, and the material between surface S7 and surface S8 is air. Surface S8 is an aspherical surface, the radius of curvature of which is -38.636 mm, the distance between surface S8 and surface S9 is 9.889 mm, and the material between surface S8 and surface S9 is chalcogenide glass. Surface S9 is an aspherical surface, and its radius of curvature is -14.388 mm. The distance between surface S9 and surface S10 is 5.543 mm, and the material between surface S9 and surface S10 is air. Surface S10 is a plane, and the distance between surface S10 and surface S11 is 0.300 mm, and the material between surface S10 and surface S11 is germanium. Surface S11 is a plane, and the distance between surface S11 and surface S12 is 2.000 mm, and the material between surface S11 and surface S12 is air. Surface S12 is a plane, and the distance between surface S12 and surface S13 is 0.725 mm, and the material between surface S12 and surface S13 is germanium. Surface S13 is a plane, and the distance between surface S13 and surface S14 is 0.500 mm, and the material between surface S13 and surface S14 is air.

[0156] Surface S1, surface S2, surface S3, surface S4, surface S8 and surface S9 are even-order aspheric surfaces, and their surface shapes satisfy the following relationship:

[0157]

[0158] 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 SS; 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, etc. of surface 2, surface 3, surface 6 and surface 7 can be obtained from Table 3.

[0159] Table 3. Coefficients of the even-order aspheric surfaces in the infrared optical system 100 provided in Example 1

[0160] Serial number S1 S2 S3 S4 S8 S9 K -4.626525 -1.272837 -0.108378 0.028481 9.842111 -0.756416 4th order coefficients 1.10562E-04 2.71212E-04 1.58831E-05 1.73719E-05 -2.26001E-04 -4.83620E-05 6th order coefficient -5.42997E-07 3.34040E-07 -1.40981E-08 -5.94473E-08 -2.14123E-06 -2.58915E-07 8th order coefficient 8.78499E-10 -2.69782E-08 -3.68684E-10 -1.38358E-09 -4.51405E-08 1.24415E-10 10th order coefficient -3.84773E-13 1.09272E-10 -8.61822E-13 -5.03568E-12 9.40167E-11 1.37056E-11

[0161] See also Figure 2 , Figure 2 The MTF (Modulation Transfer Function, MTF for short) field of view curve of the infrared optical system 100 provided in Example 1 is shown. MTF is also called modulation transfer function, which is an important indicator for describing the imaging quality of an optical system. The larger the MTF value, the better the imaging quality. Figure 2 The table lists the sagittal curve S1 and meridional curve T1 of the MTF of 15lp / mm spatial frequency as it changes with the field of view, the sagittal image curve S2 and meridional image curve T2 of the MTF of 30lp / mm spatial frequency as it changes with the field of view, the sagittal image curve S3 and meridional image curve T3 of the MTF of 45lp / mm spatial frequency as it changes with the field of view, and the sagittal curve S4 and meridional curve T4 of the MTF of 62.5lp / mm spatial frequency as it changes with the field of view.

[0162] in, Figure 2 The horizontal axis in is the image height, and its unit is millimeters. Figure 2 The vertical axis in is the MTF value. It can be seen from the above eight curves that the MTF of the infrared optical system 100 in the whole field of view is almost all greater than 0.2. Within the 0.8 field of view (5.248 mm), the MTF value of 62.5lp / mm is greater than 0.25, so the imaging quality of the infrared optical system 100 is better.

[0163] Figure 3 The figure shows the field curvature of the infrared optical system 100 provided in Example 1 under infrared light with wavelengths of 8 microns, 10 microns and 12 microns, wherein L1, L2 and L3 are the field curvatures of infrared light with wavelengths of 8 microns, 10 microns and 12 microns in the meridian direction, and S1, S2 and S3 are the field curvatures of infrared light with wavelengths of 8 microns, 10 microns and 12 microns in the sagittal direction. Figure 3 It can be seen that within the full field of view, the central wavelength meridian field curvature is less than 0.025 mm, and the sagittal field curvature is less than 0.056 mm, which meets the requirements for field curvature in the excellent imaging quality standard.

[0164] Figure 4 The distortion grid diagram of the infrared optical system 100 provided in Example 1 is shown. The field of view of the infrared optical system 100 is 120°×96°. Figure 4 It can be seen that the optical distortion of the infrared optical system 100 is -45.12%, and the TV distortion is -23.41%, which meets the imaging requirements of a wide-angle lens.

[0165] Figure 5 The point diagram of the infrared optical system 100 provided in Example 1 is shown. The root mean square error radius (RMS radius) of the light spot in the entire field of view is smaller than the radius of the Airy disk, the imaging position is concentrated, and the resolution is high.

[0166] Figure 6 The relative illumination curve of the infrared optical system 100 provided in Example 1 is shown in FIG. Figure 6 It can be seen that the relative illumination in the entire field of view is greater than 79%, and the brightness of the picture is relatively uniform.

[0167] Figure 7 The phase curve of the superlens 3 is shown.

[0168] Example 2

[0169] Figure 8 The schematic diagram of the architecture layout of the infrared optical system 100 provided in Example 2 is shown. In Example 2, the effective focal length of the infrared optical system 100 is 4.83 mm, and the infrared optical system 100 includes, along the optical axis S from the object plane A to the image plane B, a first aspheric lens 1, a second aspheric lens 2, an aperture 5, a super lens 3, a third aspheric lens 4, a protective member 6, and a window material 7. Starting from the object plane, along the optical axis S from the object plane A to the image plane B, the surfaces in the infrared optical system 100 are numbered, and the parameters of the surfaces are summarized to obtain the following Table 4.

[0170] Table 4. Parameters of various surfaces in the infrared optical system 100 provided in Example 2

[0171]

[0172]

[0173] Since the order of the surfaces in Example 2 is consistent with that in Example 1, the analysis of the planes in Table 4 can refer to Example 1, and this example does not analyze each surface one by one.

[0174] Surface S1, surface S2, surface S3, surface S4, surface S8 and surface S9 are even-order aspheric surfaces, and their surface shapes satisfy the following relationship:

[0175]

[0176] 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 SS; 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, etc. of surface 2, surface 3, surface 6 and surface 7 can be obtained from Table 5.

[0177] Table 5. Coefficients of the even-order aspheric surfaces in the infrared optical system 100 provided in Example 2

[0178] Serial number S1 S2 S3 S4 S8 S9 K -2.354523 -1.125728 0.056935 0.003342 22.766106 -0.685175 4th order coefficients 1.02970E-04 2.06691E-04 2.10232E-05 -2.29501E-05 -2.64941E-04 -5.23057E-05 6th order coefficient -8.73197E-07 -2.57879E-07 -3.17545E-07 -3.79577E-07 -3.82218E-06 -3.29067E-07 8th order coefficient 1.09502E-09 -1.14397E-08 -3.34109E-10 -9.61266E-09 -5.16163E-08 -1.50237E-10 10th order coefficient 7.01612E-12 -1.81065E-10 -3.34206E-13 -3.69179E-11 -1.54914E-09 2.05248E-11

[0179] See also Fig. 9 , Fig. 9 The MTF field of view curve diagram of the infrared optical system 100 provided in Example 2 is shown. Figure 3 The table lists the sagittal curve S1 and meridional curve T1 of the MTF of 15lp / mm spatial frequency as it changes with the field of view, the sagittal image curve S2 and meridional image curve T2 of the MTF of 30lp / mm spatial frequency as it changes with the field of view, the sagittal image curve S3 and meridional image curve T3 of the MTF of 45lp / mm spatial frequency as it changes with the field of view, and the sagittal curve S4 and meridional curve T4 of the MTF of 62.5lp / mm spatial frequency as it changes with the field of view.

[0180] in, Fig. 9 The horizontal axis in is the image height, and its unit is millimeters. Fig. 9 The vertical axis in is the MTF value. It can be seen from the above eight curves that the MTF of the infrared optical system 100 in the whole field of view is almost all greater than 0.2. Within the 0.8 field of view (5.248 mm), the MTF value of 62.5lp / mm is greater than 0.24, so the imaging quality of the infrared optical system 100 is better.

[0181] Fig.10 The figure shows the field curvature of the infrared optical system 100 provided in Example 2 under infrared light with wavelengths of 8 microns, 10 microns and 12 microns, wherein L1, L2 and L3 are the field curvatures of infrared light with wavelengths of 8 microns, 10 microns and 12 microns in the meridian direction, and S1, S2 and S3 are the field curvatures of infrared light with wavelengths of 8 microns, 10 microns and 12 microns in the sagittal direction. Fig.10 It can be seen that within the full field of view, the central wavelength meridian field curvature is less than 0.06 mm, and the sagittal field curvature is less than 0.08 mm, which meets the requirements for field curvature in the excellent imaging quality standard.

[0182] Fig.11The distortion grid diagram of the infrared optical system 100 provided in Example 2 is shown. The field of view of the infrared optical system 100 is 120°×96°. Fig.11 It can be seen that the optical distortion of the infrared optical system 100 is -47.68%, and the TV distortion is -24.29%, which meets the imaging requirements of a wide-angle lens.

[0183] Fig.12 The point diagram of the infrared optical system 100 provided in Example 2 is shown. The root mean square error radius (RMS radius) of the light spot in the entire field of view is smaller than the radius of the Airy disk, the imaging position is concentrated, and the resolution is high.

[0184] Fig.13 The relative illumination curve of the infrared optical system 100 provided in Example 2 is shown in FIG. Fig.13 It can be seen that the relative illumination in the entire field of view is greater than 76%, and the brightness of the picture is relatively uniform.

[0185] Fig.14 The phase curve of the superlens 3 is shown.

[0186] Example 3

[0187] Fig.15 The schematic diagram of the architecture layout of the infrared optical system 100 provided in Example 3 is shown. In Example 3, the effective focal length of the infrared optical system 100 is 4.75 mm. The infrared optical system 100 includes, along the optical axis S from the object plane A to the image plane B, a first aspheric lens 1, a second aspheric lens 2, an aperture 5, a super lens 3, a third aspheric lens 4, a protective member 6, and a window material 7. Starting from the object plane, along the optical axis S from the object plane A to the image plane B, the surfaces in the infrared optical system 100 are numbered, and the parameters of the surfaces are summarized to obtain the following Table 6.

[0188] Table 6. Parameters of various surfaces in the infrared optical system 100 provided in Example 3

[0189]

[0190]

[0191] Since the order of the surfaces in Example 3 is consistent with that in Example 1, the analysis of the planes in Table 6 can refer to Example 1, and this example does not analyze each surface one by one.

[0192] Surface S1, surface S2, surface S3, surface S4, surface S8 and surface S9 are even-order aspheric surfaces, and their surface shapes satisfy the following relationship:

[0193]

[0194] 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 SS; 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, etc. of surface 2, surface 3, surface 6 and surface 7 can be obtained from Table 7.

[0195] Table 7. Coefficients of the even-order aspheric surfaces in the infrared optical system 100 provided in Example 3

[0196] Serial number S1 S2 S3 S4 S8 S9 K -0.968986 -0.608656 -0.113255 78.364592 18.384735 -0.546869 4th order coefficients 3.39331E-07 6.48311E-05 2.87967E-08 -2.31703E-05 -3.22131E-04 -6.76836E-05 6th order coefficient -2.50386E-07 -1.02944E-06 -1.62605E-07 -1.12129E-07 3.06186E-06 -3.92891E-07 8th order coefficient 5.36899E-10 9.33488E-10 -6.50533E-10 -6.00025E-10 -3.85797E-07 -6.91963E-10 10th order coefficient 2.36129E-13 -1.37691E-10 -4.19314E-12 3.15073E-12 8.07237E-09 1.18906E-11

[0197] See also Fig.16 , Fig.16 The MTF field of view curve diagram of the infrared optical system 100 provided in Example 3 is shown. Fig.16 The table lists the sagittal curve S1 and meridional curve T1 of the MTF of 15lp / mm spatial frequency as it changes with the field of view, the sagittal image curve S2 and meridional image curve T2 of the MTF of 30lp / mm spatial frequency as it changes with the field of view, the sagittal image curve S3 and meridional image curve T3 of the MTF of 45lp / mm spatial frequency as it changes with the field of view, and the sagittal curve S4 and meridional curve T4 of the MTF of 62.5lp / mm spatial frequency as it changes with the field of view.

[0198] in, Fig.16 The horizontal axis in is the image height, and its unit is millimeters. Fig.16 The vertical axis in is the MTF value. It can be seen from the above eight curves that the MTF of the infrared optical system 100 in the whole field of view is all greater than 0.2. Within the 0.8 field of view (5.248 mm), the MTF value of 62.5lp / mm is greater than 0.2, so the imaging quality of the infrared optical system 100 is better.

[0199] Fig.17 The figure shows the field curvature of the infrared optical system 100 provided in Example 3 under infrared light with wavelengths of 8 microns, 10 microns and 12 microns, where L1, L2 and L3 are the field curvatures of infrared light with wavelengths of 8 microns, 10 microns and 12 microns in the meridian direction, and S1, S2 and S3 are the field curvatures of infrared light with wavelengths of 8 microns, 10 microns and 12 microns in the sagittal direction. Fig.17 It can be seen that within the full field of view, the central wavelength meridian field curvature is less than 0.127 mm, and the sagittal field curvature is less than 0.036 mm, which meets the requirements for field curvature in the excellent imaging quality standard.

[0200] Fig.18 The distortion grid diagram of the infrared optical system 100 provided in Example 3 is shown. The field of view of the infrared optical system 100 is 120°×96°. Fig.18It can be seen that the optical distortion of the infrared optical system 100 is -46.40%, and the TV distortion is -23.60%, which meets the imaging requirements of a wide-angle lens.

[0201] Fig.19 The point diagram of the infrared optical system 100 provided in Example 3 is shown. The root mean square error radius (RMS radius) of the light spot in the entire field of view is smaller than the radius of the Airy disk, the imaging position is concentrated, and the resolution is high.

[0202] Fig. 20 The relative illumination curve of the infrared optical system 100 provided in Example 3 is shown. Fig. 20 It can be seen that the relative illumination in the entire field of view is greater than 80%, and the brightness of the picture is relatively uniform.

[0203] Fig.21 The phase curve of the superlens 3 is shown.

[0204] Example 4

[0205] Fig. 22 The schematic diagram of the architecture layout of the infrared optical system 100 provided in Example 4 is shown. In Example 4, the effective focal length of the infrared optical system 100 is 4.82 mm, and the infrared optical system 100 includes, along the optical axis S from the object plane A to the image plane B, a first aspheric lens 1, a second aspheric lens 2, an aperture 5, a super lens 3, a third aspheric lens 4, a protective member 6, and a window material 7. Starting from the object plane, along the optical axis S from the object plane A to the image plane B, the surfaces in the infrared optical system 100 are numbered, and the parameters of the surfaces are summarized to obtain the following Table 8.

[0206] Table 8. Parameters of various surfaces in the infrared optical system 100 provided in Example 4

[0207]

[0208]

[0209] Since the order of the surfaces in Example 4 is consistent with that in Example 1, the analysis of the planes in Table 8 can refer to Example 1, and this example does not analyze each surface one by one.

[0210] Surface S1, surface S2, surface S3, surface S4, surface S8 and surface S9 are even-order aspheric surfaces, and their surface shapes satisfy the following relationship:

[0211]

[0212] 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 SS; c is the surface 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, etc. of surface 2, surface 3, surface 6 and surface 7 can be obtained from Table 9.

[0213] Table 9. Coefficients of the even-order aspheric surfaces in the infrared optical system 100 provided in Example 4

[0214] Serial number S1 S2 S3 S4 S8 S9 K -2.395070 -1.268647 -0.438957 0.002877 15.820259 -0.179030 4th order coefficients 7.67401E-05 1.86814E-04 1.05246E-05 -2.01151E-05 -2.41292E-04 -7.13033E-05 6th order coefficient -7.07741E-07 3.84061E-07 -3.67411E-07 -6.27607E-07 -2.57510E-06 -4.33573E-07 8th order coefficient 1.07799E-09 -2.48652E-08 -2.58628E-09 -3.95651E-09 -5.81567E-08 3.46264E-10 10th order coefficient 3.41525E-12 6.77736E-12 -1.55082E-11 4.04257E-11 -2.61119E-10 3.92730E-12

[0215] See also Fig.23 , Fig.23 FIG. 4 shows the MTF field curve of the infrared optical system 100 provided in Example 4. MTF is also called modulation transfer function. Figure 2 The table lists the sagittal curve S1 and meridional curve T1 of the MTF of 15lp / mm spatial frequency as it changes with the field of view, the sagittal image curve S2 and meridional image curve T2 of the MTF of 30lp / mm spatial frequency as it changes with the field of view, the sagittal image curve S3 and meridional image curve T3 of the MTF of 45lp / mm spatial frequency as it changes with the field of view, and the sagittal curve S4 and meridional curve T4 of the MTF of 62.5lp / mm spatial frequency as it changes with the field of view.

[0216] in, Fig.23 The horizontal axis in is the image height, and its unit is millimeters. Fig.23 The vertical axis in is the MTF value. It can be seen from the above eight curves that the MTF value of the infrared optical system 100 within the 0.8 field of view (5.248 mm) at 62.5 lp / mm is greater than 0.23, so the imaging quality of the infrared optical system 100 is relatively good.

[0217] Fig.24 The figure shows the field curvature of the infrared optical system 100 provided in Example 4 under infrared light with wavelengths of 8 microns, 10 microns and 12 microns, wherein L1, L2 and L3 are the field curvatures of infrared light with wavelengths of 8 microns, 10 microns and 12 microns in the meridian direction, and S1, S2 and S3 are the field curvatures of infrared light with wavelengths of 8 microns, 10 microns and 12 microns in the sagittal direction. Figure 3 It can be seen that within the full field of view, the central wavelength meridian field curvature is less than 0.06 mm, and the sagittal field curvature is less than 0.05 mm, which meets the requirements for field curvature in the excellent imaging quality standard.

[0218] Fig.25 The distortion grid diagram of the infrared optical system 100 provided in Example 4 is shown. The field of view of the infrared optical system 100 is 120°×96°. Fig.25It can be seen that the optical distortion of the infrared optical system 100 is -47.58%, and the TV distortion is -24.29%, which meets the imaging requirements of a wide-angle lens.

[0219] Fig.26 The point diagram of the infrared optical system 100 provided in Example 4 is shown. The root mean square error radius (RMS radius) of the light spot in the entire field of view is smaller than the radius of the Airy disk, the imaging position is concentrated, and the resolution is high.

[0220] Fig. 27 The relative illumination curve of the infrared optical system 100 provided in Example 4 is shown. Figure 6 It can be seen that the relative illumination in the entire field of view is greater than 75%, and the brightness of the picture is relatively uniform.

[0221] Fig.28 The phase curve of the superlens 3 is shown.

[0222] In summary, the infrared optical system 100 provided in the present application can match an imaging detector with high resolution and small pixels and large image plane. The resolution of the imaging detector is 1280×1024, the pixel size is 8 microns, the image plane size is 10.24 mm×8.192 mm, and the maximum image plane diameter is 13.12 mm. The horizontal field of view of the infrared optical system 100 reaches 120°, has a large imaging range, can obtain more imaging information, and can distinguish more imaging details. Since the infrared optical system 100 uses a relatively small number of lenses, the infrared optical system 100 also has the advantage of low cost. The total optical length of the infrared optical system 100 is less than 50 mm, so the infrared optical system 100 also has the advantage of a small size.

[0223] After summarizing the various parameters of the infrared optical system 100 provided by the above four embodiments, the following Table 9 is obtained. The display of Table 9 is mainly used to illustrate that the various conditions satisfied by the infrared optical system 100 provided by the present application are all verified and supported by experiments.

[0224] Table 9. Parameters of the infrared optical system 100 provided in various embodiments

[0225]

[0226]

[0227]

[0228] See also Fig.29The present application also provides an infrared optical lens 1000, which includes an imaging detector (not shown) and the above-mentioned infrared optical system 100. The architecture of the infrared optical system 100 can be found above, and its specific architecture will not be described herein.

[0229] The imaging detector is arranged on the image plane of the infrared optical system 100 , and the imaging detector includes but is not limited to CMOS (Complementary Metal Oxide Semiconductor, abbreviated as CMOS) and CCD (Charge Coupled Device, abbreviated as CCD).

[0230] In some embodiments, the resolution of the image generated by the imaging detector is 1280×1024, so that the image generated by the imaging detector can distinguish more details and has better imaging quality.

[0231] In some embodiments, the imaging detector has a pixel size of 8 μm.

[0232] In some embodiments, a dimension of the imaging detector along a first direction is 10.24 mm, a dimension of the imaging detector along a second direction is 8.192 mm, and the first direction is perpendicular to the second direction.

[0233] See also Fig.29 In some embodiments, the infrared optical lens 1000 further includes a lens barrel 200, which is roughly cylindrical and has a mounting through hole 2001. The mounting through hole 2001 is used to provide a receiving space for the optical system 100. The mounting through hole 2001 includes a first hole segment 2001a, a second hole segment 2001b, a third hole segment 2001c and a fourth hole segment 2001d in sequence from the object plane A to the image plane B along the optical axis S.

[0234] The diameter of the first hole segment 2001a on the side close to the second hole segment 2001b is larger than the diameter of the second hole segment 2001b on the side close to the first hole segment 2001a, so that the connection transition between the first hole segment 2001a and the second hole segment 2001b is in a step shape. The first aspheric lens 1 is accommodated in the side of the first hole segment 2001a close to the second hole segment 2001b, that is, the first aspheric lens 1 is installed at the step, which can prevent the first aspheric lens 1 from moving toward the image surface B.

[0235] The diameter of the second hole segment 2001b on the side close to the third hole segment 2001c is larger than the diameter of the third hole segment 2001c on the side close to the second hole segment 2001b, so that the connection transition between the second hole segment 2001b and the third hole segment 2001c is in a step shape. The super lens 3 is accommodated in the side of the second hole segment 2001b close to the third hole segment 2001c, that is, the super lens 3 is installed at the step in the lens barrel 1, which can prevent the super lens 3 from moving toward the image plane B.

[0236] The diameter of the third hole segment 2001c on the side close to the fourth hole segment 2001d is larger than the diameter of the fourth hole segment 2001d on the side close to the third hole segment 2001c, so that the connection transition between the third hole segment 2001c and the fourth hole segment 2001d is in a step shape. The third aspheric lens 4 is accommodated in the side of the third hole segment 2001c close to the fourth hole segment 2001d, that is, the third aspheric lens 4 is installed at the step in the lens barrel 1, which can prevent the third aspheric lens 4 from moving toward the image plane B.

[0237] See also Fig.29 In some embodiments, the infrared optical lens 1000 further includes a pressure ring 300 , a first spacer ring 400 and a second spacer ring 500 .

[0238] The pressing ring 300 is generally annular, and is received in the first hole section 2001a. The pressing ring 300 is connected to the inner wall of the lens barrel 1, and the pressing ring 300 abuts against the surface of the first aspheric lens 1 close to the object surface A to fix the first aspheric lens 1. Since the first aspheric lens 1 is installed at the step in the lens barrel 1, the shaking degree of the first aspheric lens 1 can be reduced, and its installation stability can be improved.

[0239] The first spacer ring 400 is roughly annular and is accommodated in the second hole section 2001b. The first spacer ring 400 is connected to the inner wall of the lens barrel 1. One side of the first spacer ring 400 abuts against the surface of the first aspheric lens 1 close to the image plane B, and the other side of the first spacer ring 400 abuts against the surface of the second aspheric lens 2 close to the object plane A.

[0240] The second spacer 500 is generally annular, and is received in the second hole section 2001b. The second spacer 500 is located on the side of the first spacer 400 close to the image plane B, and is connected to the inner wall of the lens barrel 1. One side of the second spacer 500 abuts against the surface of the second aspheric lens 2 close to the image plane B, and the other side of the second spacer 500 abuts against the super lens 3. Therefore, the super lens 3 is fixed at the step in the lens barrel 1 under the action of the second spacer 500, which can reduce the shaking degree of the super lens 3 and improve its installation stability.

[0241] The surface of the super lens 3 close to the image plane B is in contact with the surface of the third aspheric lens 4 close to the object plane A, so that the third aspheric lens 4 is fixed at the step in the lens barrel 1 under the action of the super lens 3 and the second spacer ring 500, which can reduce the shaking degree of the third aspheric lens 4 and improve its installation stability.

[0242] Since the surface of the second aspheric lens 2 close to the object plane A abuts against the first spacer ring 400, and the surface of the second aspheric lens 2 close to the image plane B abuts against the second spacer ring 500, the second aspheric lens 2 is fixed in the lens barrel 1, which can reduce the shaking degree of the second aspheric lens 2 and has higher installation stability.

[0243] The connection modes between the pressure ring 300 and the inner wall of the lens barrel 1 , between the first spacer ring 400 and the inner wall of the lens barrel 1 , and between the second spacer ring 500 and the inner wall of the lens barrel 1 include but are not limited to threaded connection and bonding.

[0244] The installation method of the infrared optical lens 1000 provided in the present application is roughly as follows: first, the third aspheric lens 4 is placed in a preset position in the mounting through hole 2001 of the lens barrel 1, and then the super lens 3 is placed in a preset position in the mounting through hole 2001 of the lens barrel 1, and then the second spacer 500 is placed in a preset position in the mounting through hole 2001 of the lens barrel 1. Next, the second aspheric lens 2 is placed in a preset position in the mounting through hole 2001 of the lens barrel 1, and then the first spacer 400 is placed in a preset position in the mounting through hole 2001 of the lens barrel 1. Finally, the first aspheric lens 1 is placed in a preset position in the mounting through hole 2001 of the lens barrel 1, and then the pressure ring 300 is placed in a preset position in the mounting through hole 2001 of the lens barrel 1, and the pressure ring 300 is adjusted so that the pressure ring 300 abuts against the first aspheric lens 1.

[0245] 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. An infrared optical system, characterized in that: The infrared optical system includes, from the object side to the image side along the optical axis, a first aspheric lens, a second aspheric lens, a super lens and a third aspheric lens in sequence; the first aspheric lens has a negative optical focal length, the first aspheric lens is a germanium lens, the surface of the first aspheric lens close to the object side is convex toward the object side, and the surface of the first aspheric lens away from the object side is convex toward the object side; the second aspheric lens has a positive optical focal length, the surface of the second aspheric lens close to the object side is convex toward the object side, and the surface of the second aspheric lens away from the object side is convex toward the object side or the image side; the super lens has a positive optical focal length; the third aspheric lens has a positive optical focal length, the surface of the third aspheric lens close to the object side is convex toward the image side, and the surface of the third aspheric lens away from the object side is convex toward the image side.

2. The infrared optical system according to claim 1, characterized in that: The infrared optical system meets the following requirements: Wherein, fno is the relative aperture of the infrared optical system, R1 is the radius of curvature of the surface of the first aspheric lens close to the object side, and R S1 is the effective radius of the surface of the first aspheric lens close to the object side; R9 is the curvature radius of the surface of the third aspheric lens close to the image side, and R S9 is the effective radius of the surface of the third aspheric lens close to the image side; the TTL is the total optical length of the infrared optical system, and the BFL is the back focal length of the infrared optical system.

3. The infrared optical system according to claim 1, characterized in that: The infrared optical system meets the following requirements: Among them, the R S1 is the effective radius of the surface of the first aspheric lens close to the object side, and the R S2 is the effective radius of the surface of the first aspheric lens close to the image side; the surface of the first aspheric lens close to the object side is the first surface, and the SAG 11 is the intersection of the first surface and the optical axis, and the distance from the vertex of the effective radius of the first surface on the optical axis; the surface of the first aspheric lens close to the object side is the second surface, and the SAG 12 is the distance between the intersection of the second surface and the optical axis and the vertex of the effective radius of the second surface on the optical axis.

4. The infrared optical system according to claim 1, characterized in that: The infrared optical system meets the following requirements: Among them, f is the effective focal length of the infrared optical system, Semi_FOV is half of the maximum field of view angle of the incident light of the infrared optical system, and Semi_ImgH is half of the maximum image height of the infrared optical system.

5. The infrared optical system according to claim 1, characterized in that: The infrared optical system meets the following requirements: Among them, the is the maximum value of the phase difference provided by the metalens, and the R M is the optical effective radius of the metalens.

6. The infrared optical system according to claim 1, characterized in that: The infrared optical system meets the following requirements: Wherein, R8 is the curvature radius of the surface of the third aspheric lens close to the object side, R9 is the curvature radius of the surface of the third aspheric lens close to the image side, and C S8 is the center thickness of the third aspheric lens, and the E S8 is the edge thickness of the third aspheric lens.

7. The infrared optical system according to claim 1, characterized in that: The infrared optical system meets the following requirements: Among them, the C S3 is the center thickness of the second aspheric lens, the C S45 is the distance between the surface of the second aspheric lens close to the image side and the surface of the super lens close to the object side on the optical axis; S8 is the center thickness of the third aspheric lens, and the C S67 is the distance between the surface of the superlens close to the object side and the third aspheric lens on the optical axis.

8. The infrared optical system according to claim 1, characterized in that: The infrared optical system meets the following requirements: Wherein, R4 is the curvature radius of the surface of the second aspheric lens close to the image side, and R8 is the curvature radius of the surface of the third aspheric lens close to the object side.

9. The infrared optical system according to claim 1, characterized in that: The infrared optical system meets the following requirements: Wherein, f is the effective focal length of the infrared optical system, and D is the entrance pupil diameter of the infrared optical system.

10. The infrared optical system according to claim 1, characterized in that: The infrared optical system meets the following requirements: Wherein, the BFL is the back focal length of the infrared optical system, and f is the effective focal length of the infrared optical system.

11. The infrared optical system according to claim 1, characterized in that: The infrared optical system meets the following requirements: Wherein, the BFL is the back focal length of the infrared optical system, and the TTL is the total optical length of the infrared optical system.

12. The infrared optical system according to any one of claims 1 to 11, characterized in that: The infrared optical system satisfies at least one of conditions 1, 2, 3 and 4; Condition one: Wherein, f1 is the focal length of the first aspheric lens, and f is the effective focal length of the infrared optical system; Condition two: Wherein, f2 is the focal length of the second aspherical lens, and f is the effective focal length of the infrared optical system; Condition three: Among them, the f M is the focal length of the metalens, and f is the effective focal length of the infrared optical system; Condition four: Wherein, f3 is the focal length of the third aspheric lens, and f is the effective focal length of the infrared optical system.

13. An infrared optical lens, characterized in that: include: An imaging detector and an infrared optical system as claimed in any one of claims 1 to 12; The imaging detector is arranged on the image plane of the infrared optical system.

14. The infrared optical lens according to claim 13, characterized in that: The infrared optical lens further comprises a lens barrel, the lens barrel is provided with a mounting through hole, and the mounting through hole comprises a first hole segment, a second hole segment, a third hole segment and a fourth hole segment in sequence from the object side to the image side along the optical axis; The diameter of the first hole segment on the side close to the second hole segment is larger than the diameter of the second hole segment on the side close to the first hole segment, and the first aspheric lens is accommodated in the side of the first hole segment close to the second hole segment; The diameter of the second hole segment on the side close to the third hole segment is larger than the diameter of the third hole segment on the side close to the second hole segment, the second aspheric lens and the super lens are both accommodated in the second hole segment, and the super lens is located on the side of the second hole segment close to the third hole segment; The diameter of the third hole segment on the side close to the fourth hole segment is larger than the diameter of the fourth hole segment on the side close to the third hole segment, and the third aspherical lens is accommodated in the side of the third hole segment close to the fourth hole segment.

15. The infrared optical lens according to claim 14, characterized in that: The infrared optical lens further comprises a pressure ring, a first spacer ring and a second spacer ring; The pressure ring is accommodated in the first hole section, and the pressure ring abuts against the surface of the first aspheric lens close to the object side; the first spacer is accommodated in the second hole section, one side of the first spacer abuts against the surface of the first aspheric lens close to the image side, and the other side of the first spacer abuts against the surface of the second aspheric lens close to the object side; one side of the second spacer abuts against the surface of the second aspheric lens close to the image side, and the other side of the second spacer abuts against the surface of the super lens close to the object side; the super lens abuts against the third aspheric lens.

Images