A far-infrared optical system and a far-infrared optical lens for image taking

Abstract

The application discloses a far-infrared optical system and a far-infrared optical lens for image acquisition. The far-infrared optical system for image acquisition comprises a first refractive lens, a second refractive lens and a diffractive optical element, and the first refractive lens and the second refractive lens are sequentially arranged along an optical axis from an object side to an image side. The paraxial region of the object side surface of the first refractive lens is convex to the object side, and the paraxial region of the image side surface of the first refractive lens is convex to the object side. The paraxial region of the object side surface of the second refractive lens is convex to the object side, and the paraxial region of the image side surface of the second refractive lens is convex to the object side. The far-infrared optical system for image acquisition satisfies f1>0 and f2>0, wherein f1 is the focal length of the first refractive lens, and f2 is the focal length of the second refractive lens. The far-infrared optical system for image acquisition provided by the application has a small number of lenses, which is conducive to lightening and miniaturization. Meanwhile, the far-infrared optical system for image acquisition has a large amount of light, can capture more details, and can improve the imaging quality.

Description

Technical Field

[0001] This application relates to the field of optical systems, and more particularly to a far-infrared optical system and a far-infrared optical lens for image acquisition. Background Technology

[0002] Infrared lenses image objects based on their temperature characteristics, enabling all-weather imaging. Compared to visible light imaging lenses, they are more versatile for outdoor exploration or nighttime observation.

[0003] In order to collect more light, existing far-infrared lenses typically use a larger aperture, which in turn requires more lens elements. However, using more lens elements leads to a continuous increase in lens size, which is not conducive to the requirements of lightweighting and miniaturization. Utility Model Content

[0004] To address the aforementioned technical problems, this application provides a far-infrared optical system and a far-infrared optical lens for image acquisition, aiming to provide a lightweight and miniaturized far-infrared optical system and a far-infrared optical lens with a large light intake for image acquisition.

[0005] According to one aspect of the embodiments of this application, a far-infrared optical system for image acquisition is disclosed. The far-infrared optical system for image acquisition includes: a first refractive lens, a second refractive lens, and a diffractive optical element. The first refractive lens and the second refractive lens are arranged sequentially along the optical axis from the object side to the image side.

[0006] The paraxial region of the object-side surface of the first refractive lens convexes towards the object side, and the paraxial region of the image-side surface of the first refractive lens convexes towards the object side.

[0007] The paraxial region of the object-side surface of the second refractive lens convexes towards the object side, and the paraxial region of the image-side surface of the second refractive lens convexes towards the object side;

[0008] The far-infrared optical system used for image acquisition satisfies:

[0009] f1 > 0;

[0010] f2 > 0;

[0011] Where f1 is the focal length of the first refracting lens and f2 is the focal length of the second refracting lens.

[0012] A second aspect of this application provides a far-infrared optical lens, the far-infrared optical lens comprising: an imaging detector and a far-infrared optical system for image acquisition; the imaging detector is disposed on the image plane of the far-infrared optical system for image acquisition.

[0013] The far-infrared optical system for image acquisition provided in this application includes: a first refractive lens, a second refractive lens, and a diffractive optical element. The first and second refractive lenses are arranged sequentially along the optical axis from the object side to the image side. The paraxial region of the object side of the first refractive lens convexes towards the object side, and the paraxial region of the image side of the first refractive lens also convexes towards the object side. The far-infrared optical system for image acquisition satisfies: f1 > 0; f2 > 0; where f1 is the focal length of the first refractive lens and f2 is the focal length of the second refractive lens. The far-infrared optical system for image acquisition provided in this application has a relatively small number of lenses, which is beneficial for weight reduction and miniaturization. At the same time, the far-infrared optical system for image acquisition has a large light intake, which can capture more details and thus improve image quality. Attached Figure Description

[0014] The above and other objectives, features and advantages of this application will become more apparent from a detailed description of exemplary embodiments thereof with reference to the accompanying drawings.

[0015] Figure 1 This is a schematic diagram of the architecture layout of a far-infrared optical system used for image acquisition in one embodiment.

[0016] Figure 2 This is an MTF field-of-view curve of a far-infrared optical system used for image acquisition in one embodiment.

[0017] Figure 3 This is a dot diagram of a far-infrared optical system used for image acquisition in one embodiment.

[0018] Figure 4 This is a field curve diagram of a far-infrared optical system used for image acquisition in one embodiment.

[0019] Figure 5 This is a distortion diagram of a far-infrared optical system used for image acquisition in one embodiment.

[0020] Figure 6 This is a relative illumination curve of a far-infrared optical system used for image acquisition in one embodiment.

[0021] Figure 7 This is a chromatic aberration curve of a far-infrared optical system used for image acquisition in one embodiment.

[0022] Figure 8 This is a schematic diagram of the architecture layout of a far-infrared optical system used for image acquisition in one embodiment.

[0023] Figure 9 This is an MTF field-of-view curve of a far-infrared optical system used for image acquisition in one embodiment.

[0024] Figure 10This is a field curve diagram of a far-infrared optical system used for image acquisition in one embodiment.

[0025] Figure 11 This is a distortion diagram of a far-infrared optical system used for image acquisition in one embodiment.

[0026] Figure 12 This is a schematic diagram of the architecture layout of a far-infrared optical system used for image acquisition in one embodiment.

[0027] Figure 13 This is an MTF field-of-view curve of a far-infrared optical system used for image acquisition in one embodiment.

[0028] Figure 14 This is a field curve diagram of a far-infrared optical system used for image acquisition in one embodiment.

[0029] Figure 15 This is a distortion diagram of a far-infrared optical system used for image acquisition in one embodiment.

[0030] Figure 16 This is a schematic diagram of the architecture layout of a far-infrared optical system used for image acquisition in one embodiment.

[0031] Figure 17 This is an MTF field-of-view curve of a far-infrared optical system used for image acquisition in one embodiment.

[0032] Figure 18 This is a dot diagram of a far-infrared optical system used for image acquisition in one embodiment.

[0033] Figure 19 This is a field curve diagram of a far-infrared optical system used for image acquisition in one embodiment.

[0034] Figure 20 This is a distortion diagram of a far-infrared optical system used for image acquisition in one embodiment.

[0035] Figure 21 This is a relative illumination curve of a far-infrared optical system used for image acquisition in one embodiment.

[0036] Figure 22 This is a chromatic aberration curve of a far-infrared optical system used for image acquisition in one embodiment.

[0037] Figure 23 This is a schematic diagram of the architecture layout of a far-infrared optical system used for image acquisition in one embodiment.

[0038] Figure 24 This is an MTF field-of-view curve of a far-infrared optical system used for image acquisition in one embodiment.

[0039] Figure 25 This is a field curve diagram of a far-infrared optical system used for image acquisition in one embodiment.

[0040] Figure 26 This is a distortion diagram of a far-infrared optical system used for image acquisition in one embodiment.

[0041] Figure 27 This is a schematic diagram of the architecture layout of a far-infrared optical system used for image acquisition in one embodiment.

[0042] Figure 28 This is an MTF field-of-view curve of a far-infrared optical system used for image acquisition in one embodiment.

[0043] Figure 29 This is a field curve diagram of a far-infrared optical system used for image acquisition in one embodiment.

[0044] Figure 30 This is a distortion diagram of a far-infrared optical system used for image acquisition in one embodiment.

[0045] Figure 31 This is a schematic diagram of the architecture layout of a far-infrared optical system used for image acquisition in one embodiment.

[0046] Figure 32 This is an MTF field-of-view curve of a far-infrared optical system used for image acquisition in one embodiment.

[0047] Figure 33 This is a dot diagram of a far-infrared optical system used for image acquisition in one embodiment.

[0048] Figure 34 This is a field curve diagram of a far-infrared optical system used for image acquisition in one embodiment.

[0049] Figure 35 This is a distortion diagram of a far-infrared optical system used for image acquisition in one embodiment.

[0050] Figure 36 This is a relative illumination curve of a far-infrared optical system used for image acquisition in one embodiment.

[0051] Figure 37 This is a chromatic aberration curve of a far-infrared optical system used for image acquisition in one embodiment.

[0052] Figure 38 This is a schematic diagram of the architecture layout of a far-infrared optical system used for image acquisition in one embodiment.

[0053] Figure 39 This is an MTF field-of-view curve of a far-infrared optical system used for image acquisition in one embodiment.

[0054] Figure 40 This is a field curve diagram of a far-infrared optical system used for image acquisition in one embodiment.

[0055] Figure 41This is a distortion diagram of a far-infrared optical system used for image acquisition in one embodiment.

[0056] Figure 42 This is a schematic diagram of the architecture layout of a far-infrared optical system used for image acquisition in one embodiment.

[0057] Figure 43 This is an MTF field-of-view curve of a far-infrared optical system used for image acquisition in one embodiment.

[0058] Figure 44 This is a field curve diagram of a far-infrared optical system used for image acquisition in one embodiment.

[0059] Figure 45 This is a distortion diagram of a far-infrared optical system used for image acquisition in one embodiment.

[0060] Figure Labels

[0061] 100. Far-infrared optical system for image acquisition; 10. First refractive lens; 20. Second refractive lens; 30. Diffractive optical element; 40. Aperture stop; 50. Protective glass; 60. Optical axis; 70. Object plane; 80. Image plane. Detailed Implementation

[0062] Exemplary embodiments will now be described more fully with reference to the accompanying drawings. However, these exemplary embodiments can be implemented in many forms and should not be construed as limited to the examples set forth herein; rather, they are provided to make the description of this application more comprehensive and complete, and to fully convey the concept of the exemplary embodiments to those skilled in the art. The drawings are merely illustrative of this application and are not necessarily drawn to scale. The same reference numerals in the drawings denote the same or similar parts, and therefore repeated descriptions of them will be omitted.

[0063] Furthermore, the described features, structures, or characteristics can be combined in any suitable manner in one or more exemplary embodiments. Numerous specific details are provided in the following description to give a full understanding of exemplary embodiments of this application. However, those skilled in the art will recognize that the technical solutions of this application can be practiced with one or more specific details omitted, or other modules, components, etc., can be employed. In other instances, well-known structures, methods, implementations, or operations are not shown or described in detail to avoid obscuring various aspects of this application.

[0064] Please see Figure 1 , Figure 1 A schematic diagram of the architecture layout of a far-infrared optical system 100 for image acquisition in one embodiment of this application is shown, wherein the optical axis 60S is the center line of the light beam. Figure 1In the image-capturing far-infrared optical system 100, the left side is the object side, with the object surface 70 located on the object side; the right side is the image side, with the image surface 80 located on the image side. The surface of the optical element in the image-capturing far-infrared optical system 100 closest to the object side is its object-side surface; similarly, the surface of the optical element in the image-capturing far-infrared optical system 100 closest to the image side is its image-side surface.

[0065] Please see Figure 1 The far-infrared optical system 100 for image acquisition includes: a first refractive lens 10, a second refractive lens 20 and a diffractive optical element 30, wherein the first refractive lens 10 and the second refractive lens 20 are arranged sequentially from the object side to the image side along the optical axis 60.

[0066] The paraxial region on the object side of the first refractive lens 10 convexes towards the object side, and the paraxial region on the image side of the first refractive lens 10 convexes towards the object side. In this application, "paraxial region" refers to a very small area of ​​the lens close to the optical axis 60, and the angle (aperture angle) between the light ray and the optical axis 60 is very small.

[0067] The paraxial region of the object-side surface of the second refractive lens 20 convexes towards the object side, and the paraxial region of the image-side surface of the second refractive lens 20 convexes towards the object side.

[0068] The diffractive optical element 30 is disposed in the optical path of the far-infrared optical system 100 for image acquisition. For example, the diffractive optical element 30 is disposed on the object side of the first refractive lens 10, or between the first refractive lens 10 and the second refractive lens 20, or on the image side of the second refractive lens 20. The diffractive optical element 30 includes, but is not limited to, a superlens and a binary diffractive surface.

[0069] The far-infrared optical system 100 used for image acquisition satisfies:

[0070] f1 > 0;

[0071] f2 > 0;

[0072] Where f1 is the focal length of the first refractive lens 10 and f2 is the focal length of the second refractive lens 20.

[0073] The far-infrared optical system 100 for image acquisition provided in this application has a small number of lenses, which is beneficial for weight reduction and miniaturization. At the same time, the far-infrared optical system 100 for image acquisition has a large amount of light intake, which can capture more details and thus improve image quality.

[0074] Please see Figure 42In some embodiments, the edges of both the object side and the image side of the first refractive lens 10 have inflection points. The inflection points of the first refractive lens 10 are beneficial for balancing and correcting the aberrations of the far-infrared optical system 100 used for image acquisition, thereby improving the imaging quality.

[0075] Please see Figure 16 , Figure 23 , Figure 27 In some embodiments, the edges of both the object side and the image side of the second refractive lens 20 have inflection points. The inflection points of the second refractive lens 20 are beneficial for balancing and correcting the aberrations of the far-infrared optical system 100 used for image acquisition, thereby improving the imaging quality.

[0076] Please see Figure 31 In some embodiments, the edge of the image-side surface of the second refractive lens 20 has a curvature point. The curvature point of the second refractive lens 20 is beneficial for balancing and correcting the aberrations of the far-infrared optical system 100 used for image acquisition, thereby improving the image quality.

[0077] In some embodiments, the diffractive optical element 30 is a binary diffractive surface. A binary diffractive surface refers to a special type of optical surface that controls the diffraction behavior of light by forming a specific binary structure on its surface. The binary diffractive surface is disposed on the object-side surface of the first refractive lens 10, or on the image-side surface of the first refractive lens 10, or on the object-side surface of the second refractive lens 20, or on the image-side surface of the second refractive lens 20. When the diffractive optical element 30 is a binary diffractive surface, the binary diffractive surface is integrated into the surface of the first refractive lens 10 or the second refractive lens 20, which can improve the integration of the far-infrared optical system 100 used for image acquisition and help reduce the size and weight of the far-infrared optical system 100 used for image acquisition.

[0078] The absolute value of the maximum phase difference of the binary diffraction plane satisfy: It is worth mentioning that the absolute value of the maximum phase difference of the aforementioned binary diffraction planes The range is obtained based on the actual phase distribution of the binary diffraction surface. Since the phase is a periodic function of 2π, there exists a relationship... (n is an integer). Therefore, the phase of the binary diffraction surface can be normalized by taking the remainder of 2π as needed to meet the actual processing requirements of the binary diffraction surface.

[0079] The design formula for a binary diffraction surface satisfies the following formula:

[0080]

[0081] Where r is the radius of the binary diffraction surface, r0 is the normalized radius of the diffraction surface, and A i is the phase coefficient of the diffraction surface, and N is the number of terms in the polynomial.

[0082] Further, please refer to Figure 1 , Figure 8 , Figure 12 , Figure 16 , Figure 23 , Figure 27 , Figure 31 , Figure 38 , Figure 42 In some embodiments, the diffractive optical element 30 is a binary diffractive surface, and the binary diffractive surface is disposed on the image side of the first refractive lens 10, so that the far-infrared optical system 100 used for image acquisition has excellent imaging quality.

[0083] In some embodiments, the far-infrared optical system 100 for image acquisition satisfies equation (1):

[0084]

[0085] Wherein, FNO is the aperture number of the far-infrared optical system 100 used for image acquisition, that is, FNO is the F-number of the far-infrared optical system 100 used for image acquisition, and FNO characterizes the light-gathering capability of the far-infrared optical system 100 used for image acquisition. D1 is the maximum effective diameter of the first refractive lens 10. In this application, the maximum effective diameter of the lens refers to the larger of the diameter of the maximum light-transmitting area on the object side of the lens and the diameter of the maximum light-transmitting area on the image side of the lens, that is, D1 is the larger of the diameter of the maximum light-transmitting area on the object side of the first refractive lens 10 and the diameter of the maximum light-transmitting area on the image side of the first refractive lens 10. TTL (Total Track Length, abbreviated as TTL) is the total optical length of the far-infrared optical system 100 used for image acquisition. RDY 11 Let RDY be the radius of curvature of the object-side surface of the first refractive lens 10. 12 Let RDY be the radius of curvature of the image-side surface of the first refracting lens 10. 21 Let RDY be the radius of curvature of the object-side surface of the second refractive lens 20. 22 Let D1 be the radius of curvature of the image-side surface of the second refracting lens 20. (D1, TTL, RDY) 11 RDY 12 RDY 21 RDY 22 All of these are units of length, such as millimeters.

[0086] Equation (1) ensures that the far-infrared optical system 100 used for image acquisition has a small size while meeting the requirements of large aperture and high light intake, and at the same time has excellent imaging quality.

[0087] In some embodiments, the far-infrared optical system 100 for image acquisition satisfies equation (2):

[0088]

[0089] Wherein, CT1 is the center thickness of the first refractive lens 10, that is, CT1 is the thickness of the first refractive lens 10 along the optical axis 60. ET1 is the edge thickness of the first refractive lens 10, and CT2 is the center thickness of the second refractive lens 20, that is, CT2 is the thickness of the second refractive lens 20 along the optical axis 60. ET2 is the edge thickness of the second refractive lens 20. The dimensions of CT1, ET1, CT2, and ET2 are all units of length, such as millimeters.

[0090] Equation (2) is the ratio of the difference between the center thickness and the edge thickness of the first refractive lens 10 to the difference between the center thickness and the edge thickness of the second refractive lens 20. Condition (2) ensures that the far-infrared optical system 100 used for image acquisition has a small total optical length and controls the distance between the lenses. Simultaneously, satisfying condition (2) can reduce the inflection points on the surfaces of the first refractive lens 10 and the second refractive lens 20, thereby reducing the processing difficulty of the first refractive lens 10 and the second refractive lens 20 and improving processing efficiency.

[0091] In some embodiments, the far-infrared optical system 100 for image acquisition satisfies equation (3):

[0092]

[0093] Where f1 is the focal length of the first refractive lens 10 and f2 is the focal length of the second refractive lens 20. The dimensions of f1 and f2 are both units of length, such as millimeters.

[0094] Equation (3) can ensure that the optical power distribution of the far-infrared optical system 100 used for image acquisition is relatively uniform, which can reduce the tolerance sensitivity of the far-infrared optical system 100 used for image acquisition and is conducive to improving product yield.

[0095] In some embodiments, the far-infrared optical system 100 for image acquisition satisfies equation (4):

[0096]

[0097] Where f1 is the focal length of the first refractive lens 10, f2 is the focal length of the second refractive lens 20, f is the effective focal length of the far-infrared optical system 100 used for image acquisition, and FNO is the aperture number of the far-infrared optical system 100 used for image acquisition. The dimensions of f1, f2, and f are all units of length, such as millimeters.

[0098] Equation (4) can ensure that the optical power distribution of the far-infrared optical system 100 used for image acquisition is relatively uniform, which can reduce the tolerance sensitivity of the far-infrared optical system 100 used for image acquisition and is conducive to improving product yield.

[0099] In some embodiments, the far-infrared optical system 100 for image acquisition satisfies equation (5):

[0100]

[0101] Where TTL is the total optical length of the far-infrared optical system 100 used for image acquisition, ImgH is the radius of the imaging area of ​​the far-infrared optical system 100 on the image plane 80, that is, the half-image height of the far-infrared optical system 100 used for image acquisition. f2 is the focal length of the second refractive lens 20. The dimensions of TTL, ImgH, and f2 are all units of length, such as millimeters.

[0102] Equation (5) indirectly constrains the incident beam at the second refractive lens 20 by constraining the focal length of the second refractive lens 20, which can effectively reduce the transverse chromatic aberration generated by the far-infrared optical system 100 used for image acquisition.

[0103] In some embodiments, the far-infrared optical system 100 for image acquisition satisfies equation (6):

[0104]

[0105] Where D1 is the maximum effective diameter of the first refractive lens 10, D2 is the maximum effective diameter of the second refractive lens 20, and FOV (Field of View) is the maximum field of view of the far-infrared optical system 100 used for image acquisition. The dimensions of D1 and D2 are both units of length, such as millimeters. The dimensions of FOV are both units of angle, such as degrees.

[0106] Equation (6) can ensure that the apertures of the first refractive lens 10 and the second refractive lens 20 are reasonably allocated to achieve clear imaging of light within the incident angle range.

[0107] In some embodiments, the far-infrared optical system 100 for image acquisition satisfies equation (7):

[0108]

[0109] Where f1 is the focal length of the first refractive lens 10, n1 is the refractive index of the first refractive lens 10, FNO is the aperture number of the far-infrared optical system 100 used for image acquisition, and RDY 11 Let RDY be the radius of curvature of the object-side surface of the first refractive lens 10. 12 Let f1 and RDY be the radius of curvature of the image-side surface of the first refractive lens 10. 11 RDY 12 All of these are units of length, such as millimeters.

[0110] Equation (7) ensures that the far-infrared optical system 100 used for image acquisition has a large aperture and a strong ability to converge light, which can enhance the sharpness of the image and make the far-infrared optical system 100 used for image acquisition have excellent image quality.

[0111] In some embodiments, the far-infrared optical system 100 for image acquisition satisfies equation (8):

[0112]

[0113] Where f1 is the focal length of the first refractive lens 10, SAG 11 SAG is the sagitta of the object-side surface of the first refractive lens 10. 12 f1, SAG is the sagittal height of the image-side surface of the first refractive lens 10. 11 SAG 12 All of these are units of length, such as millimeters.

[0114] Equation (8) can effectively reduce the tolerance sensitivity of the far-infrared optical system 100 used for image acquisition by constraining the optical power of the first refractive lens 10, and the far-infrared optical system 100 used for image acquisition can have a high processing yield.

[0115] In some embodiments, the far-infrared optical system 100 for image acquisition satisfies equation (9):

[0116]

[0117] Where TTL is the total optical length of the far-infrared optical system 100 used for image acquisition, BFL (Back focal length) is the back focal length of the far-infrared optical system 100 used for image acquisition, and FOV is the maximum field of view of the far-infrared optical system 100 used for image acquisition. Both TTL and BFL are measured in units of length, such as millimeters. FOV is measured in units of angle, such as degrees.

[0118] Equation (9) can be used in far-infrared optical systems 100 for image acquisition to ensure image uniformity and improve the relative illumination at the edges of the image, provided that the total optical length and the optical back focus are small.

[0119] In some embodiments, the far-infrared optical system 100 for image acquisition satisfies equation (10):

[0120]

[0121] Where TTL is the total optical length of the far-infrared optical system 100 used for image acquisition, BFL is the optical back focal length of the far-infrared optical system 100 used for image acquisition, and f is the effective focal length of the far-infrared optical system 100 used for image acquisition. The dimensions of TTL, BFL, and f are all units of length, such as millimeters.

[0122] Equation (10) ensures that the far-infrared optical system 100 used for image acquisition has a reasonable length and volume, as well as a sufficiently long optical back focal length, while meeting the target specifications.

[0123] In some embodiments, the far-infrared optical system 100 for image acquisition further includes an aperture stop 40, which controls the amount of light entering the far-infrared optical system 100 for image acquisition. The aperture stop 40 is disposed on the object side of the first refractive lens 10, or the aperture stop 40 is disposed between the first refractive lens 10 and the second refractive lens 20. Specifically, the position of the aperture stop 40 can be any of the following:

[0124] (1) The aperture 40 is disposed on the object side of the first refractive lens 10, and the aperture 40 and the first refractive lens 10 are disposed at intervals;

[0125] (2) Please refer to Figure 1 , Figure 8 , Figure 12 , Figure 16 , Figure 23 , Figure 27 The aperture 40 is disposed on the object side of the first refractive lens 10, and the aperture 40 is disposed in contact with the object side of the first refractive lens 10.

[0126] (3) Please refer to Figure 31 , Figure 38 , Figure 42 The aperture 40 is positioned between the first refractive lens 10 and the second refractive lens 20.

[0127] In some embodiments, the far-infrared optical system 100 for image acquisition further includes a protective glass 50, which is the last optical element of the far-infrared optical system 100 for image acquisition along the optical axis 60 from the object side to the image side. The protective glass 50 is disposed close to the image plane 80, and the material of the protective glass 50 includes, but is not limited to, silicon and germanium.

[0128] This application provides, exemplarily, nine far-infrared optical systems 100 for image acquisition that meet usage requirements in nine embodiments. The design specifications of the far-infrared optical systems 100 for image acquisition are shown in Table 0. Next, the far-infrared optical systems 100 for image acquisition provided in various embodiments of this application will be described in detail.

[0129] Table 0. Design specifications of the far-infrared optical system 100 used for image acquisition

[0130] Effective focal length 19~25mm±5% F-number 0.9 resolution 256×192 or 640×512 Pixel size 10μm or 12μm distortion ≤|1％| Relative Illuminance ＞90％ Total optical length (TTL) <36mm Optical Back Focus (BFL) >5mm Operating band Far-infrared (8μm-12μm)

[0131] Example 1

[0132] Figure 1 A schematic diagram of the architecture layout of the far-infrared optical system 100 for image acquisition provided in Embodiment 1 is shown. Figure 1 The far-infrared optical system 100 used for image acquisition includes, along the optical axis 60 from the object plane 70 to the image plane 80, the following components in sequence: an aperture stop 40, a first refractive lens 10, a diffractive optical element 30, a second refractive lens 20, and a protective glass 50. The aperture stop 40 is located on the object-side surface of the first refractive lens 10. The diffractive optical element 30 is a binary diffraction surface, located on the image-side surface of the first refractive lens 10. The absolute value of the maximum phase difference between the binary diffraction surfaces is... Some parameters of the far-infrared optical system 100 for image acquisition provided in Example 1 are shown in Table 1-1.

[0133] Table 1-1. Partial parameters of the far-infrared optical system 100 for image acquisition provided in Example 1

[0134] Effective focal length 25mm F-number 0.9 resolution 256×192 Pixel size 12μm distortion -0.005％ Relative Illuminance ＞98.5％ Total optical length (TTL) 35.555mm Optical Back Focus (BFL) 11.405mm Operating band Far-infrared (8μm-12μm) Maximum field of view (FOV) (2ω) 8.8°

[0135] As shown in Table 1-1, the total optical length and back focal length of the far-infrared optical system 100 used for image acquisition both meet the design specifications. The far-infrared optical system 100 has an F-number of 0.9, which can significantly increase the amount of light entering the far-infrared optical system 100 and collect as much energy as possible from the far-infrared optical system 100 when the image sensor has a low response to light energy, thereby ensuring excellent image quality.

[0136] Starting from object plane 70, along the optical axis 60 from object plane 70 to image plane 80, each surface in the far-infrared optical system 100 used for image acquisition is numbered, and the parameters of each surface are summarized to obtain Table 1-2 below.

[0137] Table 1-2. Parameters of each surface in the far-infrared optical system 100 for image acquisition provided in Example 1

[0138]

[0139] For each surface in Table 1-2, surface 0 is the object plane 70, surface 1 is the aperture stop 40. Surface 2 is the object-side surface of the first refractive lens 10, and the binary diffraction surface is disposed on surface 2; surface 3 is the image-side surface of the first refractive lens 10. Surface 4 is the object-side surface of the second refractive lens 20, and surface 5 is the image-side surface of the second refractive lens 20. Surface 6 is the object-side surface of the protective glass 50, and surface 7 is the image-side surface of the protective glass 50. Surface 8 is the image plane 80.

[0140] As shown in Table 1-2, surface 1 has an infinite radius of curvature, meaning it is a plane. The distance between surface 1 and surface 2 is -6.950 mm, where "-6.950 mm" indicates that surface 2 protrudes 6.950 mm beyond surface 1 towards the object. Surface 2 has a radius of curvature of 18.852 mm, and the distance between surface 2 and surface 3 is 5.000 mm. The material between surfaces 2 and 3 is chalcogenide glass. Surface 3 has a radius of curvature of 20.058 mm, and the distance between surface 3 and surface 4 is 16.650 mm. The material between surfaces 3 and 4 is air. Surface 4 has a radius of curvature of 27.607 mm, and the distance between surface 4 and surface 5 is 2.500 mm. The material between surfaces 4 and 5 is chalcogenide glass. Surface 5 has a radius of curvature of 62.760 mm, and the distance between surface 5 and surface 6 is 10.580 mm. The material between surfaces 5 and 6 is air. Surface 6 has an infinite radius of curvature, meaning it is a plane. The distance between surface 6 and surface 7 is 0.725 mm, and the material between them is silicon. Surface 7 has an infinite radius of curvature, meaning it is a plane. The distance between surface 7 and surface 8 is 0.100 mm, and the material between them is air.

[0141] Surfaces 2, 3, 4 and 5 are even-order aspherical surfaces, and their surface shapes satisfy equation (12):

[0142]

[0143] Equation (12) is the formula for aspherical surfaces, where Z(r) is the distance vector from the vertex of the aspherical surface along the optical axis 60 at a position with radius r; c is the surface curvature of the aspherical surface, c = 1 / R, where R is the radius of curvature of the aspherical surface; K is the conic coefficient; A, B, C, D... are aspherical coefficients. The values ​​of K, A, B, C, D... for surfaces 2, 3, 4, and 5 can be obtained from Table 1-3.

[0144] Table 1-3. Coefficients of even-order aspherical surfaces in the far-infrared optical system 100 for image acquisition provided in Example 1

[0145] 2 2.10E-01 1.04E-05 -1.43E-08 1.01E-10 4.04E-13 0 3 2.94E-02 4.09E-05 -8.37E-08 1.38E-09 -4.49E-13 0 4 1.90E+00 6.57E-05 -1.10E-06 1.61E-08 -1.08E-10 0 5 0 1.02E-04 -1.36E-06 2.04E-08 -1.34E-10 0

[0146] In this embodiment, the diffractive optical element 30 is a binary diffraction surface, and the coefficients of the binary diffraction surface can be obtained from Table 1-4.

[0147] Table 1-4. Coefficients of the binary diffraction plane in the far-infrared optical system 100 for imaging provided in Example 1

[0148] 3 Binary Diffraction Surface 11.8mm -3.21E+01 1.56E+00 -9.67E+00 4.38E+00

[0149] Please see Figure 2 , Figure 2 The diagram shows the MTF (Modulation Transfer Function) field-of-view curve of the far-infrared optical system 100 for image acquisition provided in Embodiment 1. Figure 2 The horizontal axis in the image represents the image height, and its unit is millimeters. Figure 2 The field of view is measured using image height on the horizontal axis. Figure 2 The vertical axis represents the MTF value. Figure 2 The table lists the sagittal and meridional curves of the MTF (Mean Transmission Frequency) as a function of field of view at a spatial frequency of 21 lp / mm, and the sagittal and meridional curves of the MTF at a spatial frequency of 42 lp / mm. Figure 2 It can be seen that the MTF is greater than 0.44 throughout the entire field of view, indicating that the far-infrared optical system 100 used for image acquisition has excellent imaging quality.

[0150] Please see Figure 3 , Figure 3 A dot plot of the far-infrared optical system 100 for image acquisition provided in Embodiment 1 is shown. Figure 3 It can be seen that, within the entire field of view, the RMS (root mean square) radius of the dot plot is smaller than the Airy disk radius, demonstrating that the far-infrared optical system 100 used for image acquisition has excellent light-gathering effect.

[0151] Please see Figure 4 , Figure 4 The field curvature diagram of the far-infrared optical system 100 for image acquisition provided in Embodiment 1 is shown. Figure 4 The horizontal axis represents the field curvature, measured in millimeters. Figure 4 The central vertical axis represents the field of view angle, in degrees. Figure 4 The image shows the field curvature of the far-infrared optical system 100 used for imaging under 8-micron, 10-micron, and 12-micron far-infrared light. Figure 4 As can be seen, the far-infrared optical system 100 for image acquisition provided in Example 1 has a meridional field curvature of 0.015 mm and a sagittal field curvature of 0.023 mm at the center wavelength (10 micrometers), which is extremely small and results in excellent image quality.

[0152] Please see Figure 5 , Figure 5 The distortion diagram of the far-infrared optical system 100 for image acquisition provided in Embodiment 1 is shown. Figure 5 The middle horizontal axis represents the distortion ratio. Figure 5 The central vertical axis represents the field of view angle, in degrees. Figure 5 The image shows the distortion of the far-infrared optical system 100 used for imaging under 8-micron, 10-micron, and 12-micron far-infrared light. Due to... Figure 5 The three curves almost overlap, therefore this embodiment does not distinguish between them. Figure 5 As can be seen, the maximum absolute value of distortion is only 0.005%, and the image is almost distortion-free.

[0153] Please see Figure 6 , Figure 6 The relative illumination curve of the far-infrared optical system 100 for image acquisition provided in Embodiment 1 is shown. Figure 6 The horizontal axis represents the image height, in millimeters. Figure 6 The central vertical axis represents relative illuminance, expressed as a percentage. Figure 6 It can be seen that the relative illumination is greater than 98.5% across the entire field of view, indicating that the image uniformity is good and the transition from the center to the edge is uniform.

[0154] Please see Figure 7 , Figure 7 The diagram shows the chromatic aberration curves of the far-infrared optical system 100 for image acquisition provided in Example 1 under far-infrared light with wavelengths of 8 micrometers, 10 micrometers, and 12 micrometers. Figure 7 The x-axis represents the position of light rays of different wavelengths on the perpendicular image plane 80, in micrometers. Figure 7 The ordinate represents the normalized field of view angle, in degrees. Figure 7 It can be seen that the maximum vertical chromatic difference is 3.75 micrometers across the entire field of view, which is smaller than the pixel size of 12 micrometers, demonstrating excellent chromatic difference control capabilities.

[0155] Example 2

[0156] Figure 8 A schematic diagram of the architecture layout of the far-infrared optical system 100 for image acquisition provided in Embodiment 2 is shown. Figure 8 The far-infrared optical system 100 used for image acquisition includes, along the optical axis 60 from the object plane 70 to the image plane 80, the following components in sequence: an aperture stop 40, a first refractive lens 10, a diffractive optical element 30, a second refractive lens 20, and a protective glass 50. The aperture stop 40 is located on the object-side surface of the first refractive lens 10. The diffractive optical element 30 is a binary diffraction surface, located on the image-side surface of the first refractive lens 10. The absolute value of the maximum phase difference between the binary diffraction surfaces is... Some parameters of the far-infrared optical system 100 for image acquisition provided in Example 2 are shown in Table 2-1.

[0157] Table 2-1. Partial parameters of the far-infrared optical system 100 for image acquisition provided in Example 2

[0158] Effective focal length 25mm F-number 0.9 resolution 256×192 Pixel size 12μm distortion -0.12％ Relative Illuminance ＞98％ Total optical length (TTL) 35.142mm Optical Back Focus (BFL) 11.300mm Operating band Far-infrared (8μm-12μm) Maximum field of view (FOV) (2ω) 8.8°

[0159] As shown in Table 2-1, the total optical length and back focal length of the far-infrared optical system 100 used for image acquisition both meet the design specifications. The far-infrared optical system 100 has an F-number of 0.9, which can significantly increase the amount of light entering the far-infrared optical system 100 and collect as much energy as possible from the far-infrared optical system 100 when the image sensor has a low response to light energy, thereby ensuring excellent image quality.

[0160] Starting from object plane 70, along the optical axis 60 from object plane 70 to image plane 80, each surface in the far-infrared optical system 100 used for image acquisition is numbered, and the parameters of each surface are summarized to obtain Table 2-2 below.

[0161] Table 2-2. Parameters of each surface in the far-infrared optical system 100 for image acquisition provided in Example 2

[0162]

[0163] For the analysis of each surface in Table 2-2, please refer to Example 2. This example will not analyze them again.

[0164] Surfaces 2, 3, 4 and 5 are even-order aspherical surfaces, and their surface shapes satisfy equation (12). The values ​​of K, A, B, C, D... of surfaces 2, 3, 4 and 5 can all be found in Table 2-3.

[0165] Table 2-3. Coefficients of even-order aspherical surfaces in the far-infrared optical system 100 for image acquisition provided in Example 2

[0166] 2 -7.25E-03 2.69E-06 3.61E-08 -1.91E-10 0 0 3 -6.93E-02 1.28E-05 1.23E-07 -1.80E-10 0 0 4 1.55E+00 -2.38E-05 -2.03E-07 2.78E-09 0 0 5 2.03E-02 -7.67E-05 -1.55E-07 4.99E-09 0 0

[0167] In this embodiment, the diffractive optical element 30 is a binary diffraction surface, and the coefficients of the binary diffraction surface can be obtained from Table 2-4.

[0168] Table 2-4. Coefficients of the binary diffraction plane in the far-infrared optical system 100 for imaging provided in Example 2

[0169] 3 Binary Diffraction Surface 12mm -3.19E+01 -2.22E+00 -2.19E+00 1.46E+00

[0170] Please see Figure 9 , Figure 9 The MTF field-of-view curve of the far-infrared optical system 100 for image acquisition provided in Embodiment 2 is shown. Figure 9 The horizontal axis in the image represents the image height, and its unit is millimeters. Figure 9 The field of view is measured using image height on the horizontal axis. Figure 9 The vertical axis represents the MTF value. Figure 9 The table lists the sagittal and meridional curves of the MTF (Mean Transmission Frequency) as a function of field of view at a spatial frequency of 21 lp / mm, and the sagittal and meridional curves of the MTF at a spatial frequency of 42 lp / mm. Figure 9 It can be seen that the MTF is greater than 0.46 across the entire field of view, indicating that the far-infrared optical system 100 used for image acquisition has excellent imaging quality.

[0171] The far-infrared optical system 100 for image acquisition provided in Example 2 has a dot plot RMS (root mean square) radius smaller than the Airy disk radius across the entire field of view, demonstrating that the far-infrared optical system 100 for image acquisition has excellent light-gathering effect.

[0172] Please see Figure 10 , Figure 10 The field curvature diagram of the far-infrared optical system 100 for image acquisition provided in Embodiment 2 is shown. Figure 10 The horizontal axis represents the field curvature, measured in millimeters. Figure 10 The central vertical axis represents the field of view angle, in degrees. Figure 10 The image shows the field curvature of the far-infrared optical system 100 used for imaging under 8-micron, 10-micron, and 12-micron far-infrared light. Figure 10 It can be seen that the far-infrared optical system 100 for image acquisition provided in Example 2 has a meridional field curvature of 0.002 mm and a sagittal field curvature of 0.019 mm at the center wavelength (10 micrometers), with extremely small field curvature and excellent image quality.

[0173] Please see Figure 11 , Figure 11 The distortion diagram of the far-infrared optical system 100 for image acquisition provided in Embodiment 2 is shown. Figure 11 The middle horizontal axis represents the distortion ratio. Figure 11 The central vertical axis represents the field of view angle, in degrees. Figure 11 The image shows the distortion of the far-infrared optical system 100 used for imaging under 8-micron, 10-micron, and 12-micron far-infrared light. Due to... Figure 11 The three curves almost overlap, therefore this embodiment does not distinguish between them. Figure 11 As can be seen, the maximum absolute value of distortion is only 0.12%, and the image is almost distortion-free.

[0174] The far-infrared optical system 100 for image acquisition provided in Example 2 has a relative illumination greater than 98% across the entire field of view, indicating that its image uniformity is good and the transition from the center to the edge is uniform.

[0175] The far-infrared optical system 100 for image acquisition provided in Example 2 exhibits a maximum vertical chromatic difference of 3.52 micrometers under 8-micrometer, 10-micrometer, and 12-micrometer far-infrared light across the entire field of view, which is smaller than the pixel size of 12 micrometers, demonstrating excellent chromatic difference control capabilities.

[0176] Example 3

[0177] Figure 12 A schematic diagram of the architecture layout of the far-infrared optical system 100 for image acquisition provided in Embodiment 3 is shown. Figure 12 The far-infrared optical system 100 used for image acquisition includes, along the optical axis 60 from the object plane 70 to the image plane 80, the following components in sequence: an aperture stop 40, a first refractive lens 10, a diffractive optical element 30, a second refractive lens 20, and a protective glass 50. The aperture stop 40 is located on the object-side surface of the first refractive lens 10. The diffractive optical element 30 is a binary diffraction surface, located on the image-side surface of the first refractive lens 10. The absolute value of the maximum phase difference between the binary diffraction surfaces is... Some parameters of the far-infrared optical system 100 for image acquisition provided in Example 3 are shown in Table 3-1.

[0178] Table 3-1. Partial parameters of the far-infrared optical system 100 for image acquisition provided in Example 3

[0179] Effective focal length 25mm F-number 0.9 resolution 256×192 Pixel size 12μm distortion -0.16％ Relative Illuminance ＞98.8％ Total optical length (TTL) 36.000mm Optical Back Focus (BFL) 11.337mm Operating band Far-infrared (8μm-12μm) Maximum field of view (FOV) (2ω) 8.8°

[0180] As shown in Table 3-1, the total optical length and back focal length of the far-infrared optical system 100 used for image acquisition both meet the design specifications. The far-infrared optical system 100 has an F-number of 0.9, which can significantly increase the amount of light entering the far-infrared optical system 100 and collect as much energy as possible from the far-infrared optical system 100 when the image sensor has a low response to light energy, thereby ensuring excellent image quality.

[0181] Starting from object plane 70, along the optical axis 60 from object plane 70 to image plane 80, each surface in the far-infrared optical system 100 used for image acquisition is numbered, and the parameters of each surface are summarized to obtain Table 3-2 below.

[0182] Table 3-2. Parameters of each surface in the far-infrared optical system 100 for image acquisition provided in Example 3

[0183]

[0184] The analysis of each surface in Table 3-2 can be referred to Example 1, and will not be analyzed again in this example.

[0185] Surfaces 2, 3, 4 and 5 are even-order aspherical surfaces, and their surface shapes satisfy equation (12). The values ​​of K, A, B, C, D... of surfaces 2, 3, 4 and 5 can all be found in Table 3-3.

[0186] Table 3-3. Coefficients of even-order aspherical surfaces in the far-infrared optical system 100 for image acquisition provided in Example 3

[0187] 2 -7.92E-03 3.21E-06 3.65E-08 -2.69E-11 -6.61E-14 0 3 -3.90E-02 1.45E-05 1.19E-07 -1.96E-10 -1.47E-13 0 4 2.37E+00 -1.63E-05 -6.71E-08 4.28E-09 -2.15E-11 0 5 1.09E+01 -1.44E-06 1.41E-07 5.72E-09 -2.45E-11 0

[0188] In this embodiment, the diffractive optical element 30 is a binary diffraction surface, and the coefficients of the binary diffraction surface can be obtained from Table 3-4.

[0189] Table 3-4. Coefficients of the binary diffraction plane in the far-infrared optical system 100 for imaging provided in Example 3.

[0190] 3 Binary Diffraction Surface 11.9mm -3.21E+01 3.68E+00 -1.31E+01 7.34E+00

[0191] Please see Figure 13 , Figure 13 The MTF field-of-view curve of the far-infrared optical system 100 for image acquisition provided in Embodiment 3 is shown. Figure 13 The horizontal axis in the image represents the image height, and its unit is millimeters. Figure 13 The field of view is measured using image height on the horizontal axis. Figure 13 The vertical axis represents the MTF value. Figure 13 The table lists the sagittal and meridional curves of the MTF (Mean Transmission Frequency) as a function of field of view at a spatial frequency of 21 lp / mm, and the sagittal and meridional curves of the MTF at a spatial frequency of 42 lp / mm. Figure 13 It can be seen that the MTF is greater than 0.48 across the entire field of view, indicating that the far-infrared optical system 100 used for image acquisition has excellent imaging quality.

[0192] The far-infrared optical system 100 for image acquisition provided in Example 3 has a dot plot RMS (root mean square) radius smaller than the Airy disk radius across the entire field of view, demonstrating that the far-infrared optical system 100 for image acquisition has excellent light-gathering effect.

[0193] Please see Figure 14 , Figure 14 The field curvature diagram of the far-infrared optical system 100 for image acquisition provided in Embodiment 3 is shown. Figure 14 The horizontal axis represents the field curvature, measured in millimeters. Figure 14 The central vertical axis represents the field of view angle, in degrees. Figure 14 The image shows the field curvature of the far-infrared optical system 100 used for imaging under 8-micron, 10-micron, and 12-micron far-infrared light. Figure 14It can be seen that the far-infrared optical system 100 for image acquisition provided in Example 3 has a meridional field curvature of 0.0034 mm and a sagittal field curvature of 0.0193 mm at the center wavelength (10 micrometers), which is extremely small and has excellent image quality.

[0194] Please see Figure 15 , Figure 15 The distortion diagram of the far-infrared optical system 100 for image acquisition provided in Embodiment 3 is shown. Figure 15 The middle horizontal axis represents the distortion ratio. Figure 15 The central vertical axis represents the field of view angle, in degrees. Figure 15 The image shows the distortion of the far-infrared optical system 100 used for imaging under 8-micron, 10-micron, and 12-micron far-infrared light. Due to... Figure 15 The three curves almost overlap, therefore this embodiment does not distinguish between them. Figure 15 As can be seen, the maximum absolute value of distortion is only 0.16%, and the image is almost distortion-free.

[0195] The far-infrared optical system 100 for image acquisition provided in Example 3 has a relative illumination greater than 98.8% across the entire field of view, indicating that its image uniformity is good and the transition from the center to the edge is uniform.

[0196] The far-infrared optical system 100 for image acquisition provided in Example 3 has a maximum vertical chromatic difference of 3.72 micrometers under 8-micrometer, 10-micrometer, and 12-micrometer far-infrared light, which is smaller than the pixel size of 12 micrometers, demonstrating excellent chromatic difference control capability.

[0197] Example 4

[0198] Figure 16 A schematic diagram of the architecture layout of the far-infrared optical system 100 for image acquisition provided in Embodiment 4 is shown. Figure 16 The far-infrared optical system 100 used for image acquisition includes, along the optical axis 60 from the object plane 70 to the image plane 80, the following components in sequence: an aperture stop 40, a first refractive lens 10, a diffractive optical element 30, a second refractive lens 20, and a protective glass 50. The aperture stop 40 is located on the object-side surface of the first refractive lens 10. The diffractive optical element 30 is a binary diffraction surface, located on the image-side surface of the first refractive lens 10. The absolute value of the maximum phase difference between the binary diffraction surfaces is... Some parameters of the far-infrared optical system 100 for image acquisition provided in Example 4 are shown in Table 4-1.

[0199] Table 4-1. Partial parameters of the far-infrared optical system 100 for image acquisition provided in Example 4

[0200] Effective focal length 25mm F-number 0.9 resolution 640×512 Pixel size 12μm distortion -0.4％ Relative Illuminance ＞94.6％ Total optical length (TTL) 33.806mm Optical Back Focus (BFL) 10.256mm Operating band Far-infrared (8μm-12μm) Maximum field of view (FOV) (2ω) 22.36°

[0201] As shown in Table 4-1, the total optical length and back focal length of the far-infrared optical system 100 used for image acquisition both meet the design specifications. The far-infrared optical system 100 has an F-number of 0.9, which can significantly increase the amount of light entering the far-infrared optical system 100 and collect as much energy as possible into the far-infrared optical system 100 when the image sensor has a low response to light energy, thereby ensuring excellent image quality.

[0202] Starting from object plane 70, along the optical axis 60 from object plane 70 to image plane 80, each surface in the far-infrared optical system 100 used for image acquisition is numbered, and the parameters of each surface are summarized to obtain Table 4-2 below.

[0203] Table 4-2. Parameters of each surface in the far-infrared optical system 100 for image acquisition provided in Example 4

[0204]

[0205] For the analysis of each surface in Table 4-2, please refer to Example 1. This example will not analyze them further.

[0206] Surfaces 2, 3, 4 and 5 are even-order aspherical surfaces, and their surface shapes satisfy equation (12). The values ​​of K, A, B, C, D... of surfaces 2, 3, 4 and 5 can all be found in Table 4-3.

[0207] Table 4-3. Coefficients of even-order aspherical surfaces in the far-infrared optical system 100 for image acquisition provided in Example 4

[0208]

[0209] In this embodiment, the diffractive optical element 30 is a binary diffraction surface, and the coefficients of the binary diffraction surface can be obtained from Table 4-4.

[0210] Table 4-4. Coefficients of the binary diffraction plane in the far-infrared optical system 100 for imaging provided in Example 4

[0211] 3 Binary Diffraction Surface 13.0mm -3.28E+01 -3.17E+01 7.06E+01 -5.70E+01 1.75E+01

[0212] Please see Figure 17 , Figure 17 The MTF field-of-view curve of the far-infrared optical system 100 for image acquisition provided in Embodiment 4 is shown. Figure 17 The horizontal axis in the image represents the image height, and its unit is millimeters. Figure 17 The field of view is measured using image height on the horizontal axis. Figure 17 The vertical axis represents the MTF value. Figure 17The table lists the sagittal and meridional curves of the MTF (Mean Transmission Frequency) as a function of field of view at a spatial frequency of 21 lp / mm, and the sagittal and meridional curves of the MTF at a spatial frequency of 42 lp / mm. Figure 17 It can be seen that the MTF is greater than 0.39 across the entire field of view, indicating that the far-infrared optical system 100 used for image acquisition has excellent imaging quality.

[0213] Please see Figure 18 , Figure 18 A dot plot of the far-infrared optical system 100 for image acquisition provided in Embodiment 4 is shown, according to Figure 18 It can be seen that the point array converges within the entire field of view, resulting in excellent imaging performance.

[0214] Please see Figure 19 , Figure 19 The field curvature diagram of the far-infrared optical system 100 for image acquisition provided in Embodiment 4 is shown. Figure 19 The horizontal axis represents the field curvature, measured in millimeters. Figure 19 The central vertical axis represents the field of view angle, in degrees. Figure 19 The image shows the field curvature of the far-infrared optical system 100 used for imaging under 8-micron, 10-micron, and 12-micron far-infrared light. Figure 19 It can be seen that the far-infrared optical system 100 for image acquisition provided in Example 4 has a meridional field curvature of 0.0362 mm and a sagittal field curvature of 0.0581 mm at the center wavelength (10 micrometers), which is extremely small and has excellent image quality.

[0215] Please see Figure 20 , Figure 20 The distortion diagram of the far-infrared optical system 100 for image acquisition provided in Embodiment 4 is shown. Figure 20 The middle horizontal axis represents the distortion ratio. Figure 20 The central vertical axis represents the field of view angle, in degrees. Figure 20 The image shows the distortion of the far-infrared optical system 100 used for imaging under 8-micron, 10-micron, and 12-micron far-infrared light. Due to... Figure 20 The three curves almost overlap, therefore this embodiment does not distinguish between them. Figure 20 As can be seen, the maximum absolute value of distortion is only 0.12%, and the image is almost distortion-free.

[0216] Please see Figure 21 , Figure 21 The relative illumination curve of the far-infrared optical system 100 for image acquisition provided in Embodiment 4 is shown. Figure 21 The horizontal axis represents the image height, in millimeters. Figure 21 The central vertical axis represents relative illuminance, expressed as a percentage. Figure 21It can be seen that the relative illumination is greater than 94.6% across the entire field of view, indicating that the image uniformity is good and the transition from the center to the edge is uniform.

[0217] Please see Figure 22 , Figure 22 The diagram shows the chromatic aberration curves of the far-infrared optical system 100 for image acquisition provided in Example 4 under far-infrared light with wavelengths of 8 micrometers, 10 micrometers, and 12 micrometers. Figure 22 The x-axis represents the position of light rays of different wavelengths on the perpendicular image plane 80, in micrometers. Figure 22 The ordinate represents the normalized field of view angle, in degrees. Figure 22 It can be seen that the maximum vertical chromatic difference is 5.92 micrometers across the entire field of view, which is smaller than the pixel size of 12 micrometers, demonstrating excellent chromatic difference control capabilities.

[0218] Example 5

[0219] Figure 23 A schematic diagram of the architecture layout of the far-infrared optical system 100 for image acquisition provided in Embodiment 5 is shown. Figure 23 The far-infrared optical system 100 used for image acquisition includes, along the optical axis 60 from the object plane 70 to the image plane 80, the following components in sequence: an aperture stop 40, a first refractive lens 10, a diffractive optical element 30, a second refractive lens 20, and a protective glass 50. The aperture stop 40 is located on the object-side surface of the first refractive lens 10. The diffractive optical element 30 is a binary diffraction surface, located on the image-side surface of the first refractive lens 10. The absolute value of the maximum phase difference between the binary diffraction surfaces is... Some parameters of the far-infrared optical system 100 for image acquisition provided in Example 5 are shown in Table 5-1.

[0220] Table 5-1. Partial parameters of the far-infrared optical system 100 for image acquisition provided in Example 5

[0221] Effective focal length 25mm F-number 0.9 resolution 640×512 Pixel size 12μm distortion -0.9％ Relative Illuminance ＞96％ Total optical length (TTL) 35.000mm Optical Back Focus (BFL) 10.690mm Operating band Far-infrared (8μm-12μm) Maximum field of view (FOV) (2ω) 22.4°

[0222] As shown in Table 5-1, the total optical length and back focal length of the far-infrared optical system 100 used for image acquisition both meet the design specifications. The far-infrared optical system 100 has an F-number of 0.9, which can significantly increase the amount of light entering the far-infrared optical system 100 and collect as much energy as possible from the far-infrared optical system 100 when the image sensor has a low response to light energy, thereby ensuring excellent image quality.

[0223] Starting from object plane 70, along the optical axis 60 from object plane 70 to image plane 80, each surface in the far-infrared optical system 100 used for image acquisition is numbered, and the parameters of each surface are summarized to obtain Table 5-2 below.

[0224] Table 5-2. Parameters of each surface in the far-infrared optical system 100 for image acquisition provided in Example 5

[0225]

[0226] The analysis of each surface in Table 5-2 can be referred to Example 1, and will not be analyzed again in this example.

[0227] Surfaces 2, 3, 4 and 5 are even-order aspherical surfaces, and their surface shapes satisfy equation (12). The values ​​of K, A, B, C, D... of surfaces 2, 3, 4 and 5 can all be found in Table 5-3.

[0228] Table 5-3. Coefficients of even-order aspherical surfaces in the far-infrared optical system 100 for image acquisition provided in Example 5

[0229]

[0230] In this embodiment, the diffractive optical element 30 is a binary diffraction surface, and the coefficients of the binary diffraction surface can be found in Table 5-4.

[0231] Table 5-4. Coefficients of the binary diffraction plane in the far-infrared optical system 100 for imaging provided in Example 5

[0232] 3 Binary Diffraction Surface 13.4mm -4.06E+01 5.42E+00 1.07E+00 5.45E+00 -4.40E+000

[0233] Please see Figure 24 , Figure 24 The MTF field-of-view curve of the far-infrared optical system 100 for image acquisition provided in Embodiment 5 is shown. Figure 24 The horizontal axis in the image represents the image height, and its unit is millimeters. Figure 24 The field of view is measured using image height on the horizontal axis. Figure 24 The vertical axis represents the MTF value. Figure 24 The table lists the sagittal and meridional curves of the MTF (Mean Transmission Frequency) as a function of field of view at a spatial frequency of 21 lp / mm, and the sagittal and meridional curves of the MTF at a spatial frequency of 42 lp / mm. Figure 24 It can be seen that the MTF is greater than 0.38 throughout the entire field of view, indicating that the far-infrared optical system 100 used for image acquisition has excellent imaging quality.

[0234] The far-infrared optical system 100 for image acquisition provided in Example 5 has excellent imaging effect with point pattern convergence across the entire field of view.

[0235] Please see Figure 25 , Figure 25 The field curvature diagram of the far-infrared optical system 100 for image acquisition provided in Embodiment 5 is shown. Figure 25The horizontal axis represents the field curvature, measured in millimeters. Figure 25 The central vertical axis represents the field of view angle, in degrees. Figure 25 The image shows the field curvature of the far-infrared optical system 100 used for imaging under 8-micron, 10-micron, and 12-micron far-infrared light. Figure 25 It can be seen that the far-infrared optical system 100 for image acquisition provided in Example 5 has a meridional field curvature of 0.0478 mm and a sagittal field curvature of 0.0484 mm at the center wavelength (10 micrometers), which is extremely small and has excellent image quality.

[0236] Please see Figure 26 , Figure 26 The distortion diagram of the far-infrared optical system 100 for image acquisition provided in Embodiment 5 is shown. Figure 26 The middle horizontal axis represents the distortion ratio. Figure 26 The central vertical axis represents the field of view angle, in degrees. Figure 26 The image shows the distortion of the far-infrared optical system 100 used for imaging under 8-micron, 10-micron, and 12-micron far-infrared light. Due to... Figure 26 The three curves almost overlap, therefore this embodiment does not distinguish between them. Figure 26 It can be seen that the maximum absolute value of distortion is only 0.92%, indicating that the degree of image distortion is relatively small.

[0237] The far-infrared optical system 100 for image acquisition provided in Example 5 has a relative illumination greater than 96% across the entire field of view, indicating that its image uniformity is good and the transition from the center to the edge is uniform.

[0238] The far-infrared optical system 100 for image acquisition provided in Example 5 has a maximum vertical chromatic difference of 7.85 micrometers under 8-micrometer, 10-micrometer, and 12-micrometer far-infrared light, which is smaller than the pixel size of 12 micrometers, demonstrating excellent chromatic difference control capability.

[0239] Example 6

[0240] Figure 27 A schematic diagram of the architecture layout of the far-infrared optical system 100 for image acquisition provided in Embodiment 6 is shown. Figure 27 The far-infrared optical system 100 used for image acquisition includes, along the optical axis 60 from the object plane 70 to the image plane 80, the following components in sequence: an aperture stop 40, a first refractive lens 10, a diffractive optical element 30, a second refractive lens 20, and a protective glass 50. The aperture stop 40 is located on the object-side surface of the first refractive lens 10. The diffractive optical element 30 is a binary diffraction surface, located on the image-side surface of the first refractive lens 10. The absolute value of the maximum phase difference between the binary diffraction surfaces is... Some parameters of the far-infrared optical system 100 for image acquisition provided in Example 6 are shown in Table 6-1.

[0241] Table 6-1. Partial parameters of the far-infrared optical system 100 for image acquisition provided in Example 6

[0242] Effective focal length 25mm F-number 0.9 resolution 640×512 Pixel size 12μm distortion -0.65％ Relative Illuminance ＞95％ Total optical length (TTL) 34.134mm Optical Back Focus (BFL) 10.351mm Operating band Far-infrared (8μm-12μm) Maximum field of view (FOV) (2ω) 22.38°

[0243] As shown in Table 6-1, the total optical length and back focal length of the far-infrared optical system 100 used for image acquisition both meet the design specifications. The far-infrared optical system 100 has an F-number of 0.9, which can significantly increase the amount of light entering the far-infrared optical system 100 and collect as much energy as possible from the far-infrared optical system 100 when the image sensor has a low response to light energy, thereby ensuring excellent image quality.

[0244] Starting from object plane 70, along the optical axis 60 from object plane 70 to image plane 80, each surface in the far-infrared optical system 100 used for image acquisition is numbered, and the parameters of each surface are summarized to obtain Table 6-2 below.

[0245] Table 6-2. Parameters of each surface in the far-infrared optical system 100 for image acquisition provided in Example 6

[0246]

[0247]

[0248] The analysis of each surface in Table 6-2 can be referred to Example 1, and will not be analyzed again in this example.

[0249] Surfaces 2, 3, 4 and 5 are even-order aspherical surfaces, and their surface shapes satisfy equation (12). The values ​​of K, A, B, C, D... of surfaces 2, 3, 4 and 5 can all be found in Table 6-3.

[0250] Table 6-3. Coefficients of even-order aspherical surfaces in the far-infrared optical system 100 for image acquisition provided in Example 6

[0251]

[0252] In this embodiment, the diffractive optical element 30 is a binary diffraction surface, and the coefficients of the binary diffraction surface can be found in Table 6-4.

[0253] Table 6-4. Coefficients of the binary diffraction plane in the far-infrared optical system 100 for imaging provided in Example 6

[0254] 3 Binary Diffraction Surface 13.0mm -3.39E+01 -2.03E+01 4.19E+01 -2.68E+01 6.11E+00

[0255] Please see Figure 28 , Figure 28The MTF field-of-view curve of the far-infrared optical system 100 for image acquisition provided in Embodiment 6 is shown. Figure 28 The horizontal axis in the image represents the image height, and its unit is millimeters. Figure 28 The field of view is measured using image height on the horizontal axis. Figure 28 The vertical axis represents the MTF value. Figure 28 The table lists the sagittal and meridional curves of the MTF (Mean Transmission Frequency) as a function of field of view at a spatial frequency of 21 lp / mm, and the sagittal and meridional curves of the MTF at a spatial frequency of 42 lp / mm. Figure 28 It can be seen that the MTF is greater than 0.40 throughout the entire field of view, indicating that the far-infrared optical system 100 used for image acquisition has excellent imaging quality.

[0256] The far-infrared optical system 100 for image acquisition provided in Example 6 has excellent imaging effect with point pattern convergence across the entire field of view.

[0257] Please see Figure 29 , Figure 29 The field curvature diagram of the far-infrared optical system 100 for image acquisition provided in Embodiment 6 is shown. Figure 29 The horizontal axis represents the field curvature, measured in millimeters. Figure 29 The central vertical axis represents the field of view angle, in degrees. Figure 29 The image shows the field curvature of the far-infrared optical system 100 used for imaging under 8-micron, 10-micron, and 12-micron far-infrared light. Figure 29 It can be seen that the far-infrared optical system 100 for image acquisition provided in Example 6 has a meridional field curvature of 0.0478 mm and a sagittal field curvature of 0.0484 mm at the center wavelength (10 micrometers), which is extremely small and has excellent image quality.

[0258] Please see Figure 30 , Figure 30 The distortion diagram of the far-infrared optical system 100 for image acquisition provided in Embodiment 6 is shown. Figure 30 The middle horizontal axis represents the distortion ratio. Figure 30 The central vertical axis represents the field of view angle, in degrees. Figure 30 The image shows the distortion of the far-infrared optical system 100 used for imaging under 8-micron, 10-micron, and 12-micron far-infrared light. Due to... Figure 30 The three curves almost overlap, therefore this embodiment does not distinguish between them. Figure 30 As can be seen, the maximum absolute value of distortion is only 0.65%, and the image is almost distortion-free.

[0259] The far-infrared optical system 100 for image acquisition provided in Example 6 has a relative illumination greater than 95% across the entire field of view, indicating that its image uniformity is good and the transition from the center to the edge is uniform.

[0260] The far-infrared optical system 100 for image acquisition provided in Example 6 has a maximum vertical chromatic difference of 6.62 micrometers under 8-micrometer, 10-micrometer, and 12-micrometer far-infrared light, which is smaller than the pixel size of 12 micrometers, demonstrating excellent chromatic difference control capability.

[0261] Example 7

[0262] Figure 31 A schematic diagram of the architecture layout of the far-infrared optical system 100 for image acquisition provided in Embodiment 7 is shown. Figure 31 The far-infrared optical system 100 used for image acquisition includes, along the optical axis 60 from the object plane 70 to the image plane 80, the following components in sequence: a first refractive lens 10, a diffractive optical element 30, an aperture 40, a second refractive lens 20, and a protective glass 50. The aperture 40 is located between the first refractive lens 10 and the second refractive lens 20. The diffractive optical element 30 is a binary diffraction surface, and the binary diffraction surface is located on the image side of the first refractive lens 10. The absolute value of the maximum phase difference between the binary diffraction surfaces is... Some parameters of the far-infrared optical system 100 for image acquisition provided in Example 7 are shown in Table 7-1.

[0263] Table 7-1. Partial parameters of the far-infrared optical system 100 for image acquisition provided in Example 7

[0264]

[0265]

[0266] As shown in Table 7-1, the total optical length and back focal length of the far-infrared optical system 100 used for image acquisition both meet the design specifications. The far-infrared optical system 100 has an F-number of 0.9, which can significantly increase the amount of light entering the far-infrared optical system 100 and collect as much energy as possible from the far-infrared optical system 100 when the image sensor has a low response to light energy, thereby ensuring excellent image quality.

[0267] Starting from object plane 70, along the optical axis 60 from object plane 70 to image plane 80, each surface in the far-infrared optical system 100 used for image acquisition is numbered, and the parameters of each surface are summarized to obtain Table 7-2 below.

[0268] Table 7-2. Parameters of each surface in the far-infrared optical system 100 for image acquisition provided in Example 7

[0269]

[0270] The analysis of each surface in Table 7-2 can be referred to Example 1, and will not be analyzed again in this example.

[0271] Surfaces 1, 2, 4 and 5 are even-order aspherical surfaces, and their surface shapes satisfy equation (12). The values ​​of K, A, B, C, D... of surfaces 1, 2, 4 and 5 can all be found in Table 7-3.

[0272] Table 7-3. Coefficients of even-order aspherical surfaces in the far-infrared optical system 100 for image acquisition provided in Example 7

[0273]

[0274] In this embodiment, the diffractive optical element 30 is a binary diffraction surface, and the coefficients of the binary diffraction surface can be found in Table 7-4.

[0275] Table 7-4. Coefficients of the binary diffraction plane in the far-infrared optical system 100 for imaging provided in Example 7

[0276] 2 Binary Diffraction Surface 10.0mm -1.09E+01 -5.73E+01 9.02E+01 -5.37E+01 1.04E+01

[0277] Please see Figure 32 , Figure 32 The MTF field-of-view curve of the far-infrared optical system 100 for image acquisition provided in Embodiment 7 is shown. Figure 32 The horizontal axis in the image represents the image height, and its unit is millimeters. Figure 32 The field of view is measured using image height on the horizontal axis. Figure 32 The vertical axis represents the MTF value. Figure 32 The table lists the sagittal and meridional curves of the MTF at a spatial frequency of 25 lp / mm as a function of the field of view, and the sagittal and meridional curves of the MTF at a spatial frequency of 50 lp / mm as a function of the field of view. Figure 32 It can be seen that the MTF is greater than 0.31 throughout the entire field of view, indicating that the far-infrared optical system 100 used for image acquisition has extremely high resolution and imaging quality.

[0278] Please see Figure 33 , Figure 33 A dot plot of the far-infrared optical system 100 for image acquisition provided in Embodiment 7 is shown, according to Figure 33 It can be seen that the point array converges within the entire field of view, resulting in excellent imaging performance.

[0279] Please see Figure 34 , Figure 34 The field curvature diagram of the far-infrared optical system 100 for image acquisition provided in Embodiment 7 is shown. Figure 34 The horizontal axis represents the field curvature, measured in millimeters. Figure 34 The central vertical axis represents the field of view angle, in degrees. Figure 34 The image shows the field curvature of the far-infrared optical system 100 used for imaging under 8-micron, 10-micron, and 12-micron far-infrared light. Figure 34 As can be seen, the far-infrared optical system 100 for image acquisition provided in Example 7 has a meridional field curvature of 0.0462 mm and a sagittal field curvature of 0.0226 mm at the center wavelength (10 micrometers), which is extremely small and results in excellent image quality.

[0280] Please see Figure 35 , Figure 35 The distortion diagram of the far-infrared optical system 100 for image acquisition provided in Embodiment 7 is shown. Figure 35 The middle horizontal axis represents the distortion ratio. Figure 35 The central vertical axis represents the field of view angle, in degrees. Figure 35 The image shows the distortion of the far-infrared optical system 100 used for imaging under 8-micron, 10-micron, and 12-micron far-infrared light. Due to... Figure 35 The three curves almost overlap, therefore this embodiment does not distinguish between them. Figure 35 As can be seen, the maximum absolute value of distortion is only 0.5%, and the image is almost distortion-free.

[0281] Please see Figure 36 , Figure 36 A relative illumination curve of the far-infrared optical system 100 for image acquisition provided in Embodiment 7 is shown. Figure 36 The horizontal axis represents the image height, in millimeters. Figure 36 The central vertical axis represents relative illuminance, expressed as a percentage. Figure 36 It can be seen that the relative illumination is greater than 94.5% across the entire field of view, indicating that the image uniformity is good and the transition from the center to the edge is uniform.

[0282] Please see Figure 37 , Figure 37 The diagram shows the chromatic aberration curves of the far-infrared optical system 100 for image acquisition provided in Example 7 under far-infrared light with wavelengths of 8 micrometers, 10 micrometers, and 12 micrometers. Figure 37 The x-axis represents the position of light rays of different wavelengths on the perpendicular image plane 80, in micrometers. Figure 37 The ordinate represents the normalized field of view angle, in degrees. Figure 37 It can be seen that the maximum vertical chromatic difference is 0.687 micrometers across the entire field of view, which is much smaller than the pixel size of 10 micrometers, demonstrating excellent chromatic difference control capabilities.

[0283] Example 8

[0284] Figure 38 A schematic diagram of the architecture layout of the far-infrared optical system 100 for image acquisition provided in Embodiment 8 is shown. Figure 38The far-infrared optical system 100 used for image acquisition includes, along the optical axis 60 from the object plane 70 to the image plane 80, the following components in sequence: a first refractive lens 10, a diffractive optical element 30, an aperture 40, a second refractive lens 20, and a protective glass 50. The aperture 40 is located between the first refractive lens 10 and the second refractive lens 20. The diffractive optical element 30 is a binary diffraction surface, and the binary diffraction surface is located on the image side of the first refractive lens 10. The absolute value of the maximum phase difference between the binary diffraction surfaces is... Some parameters of the far-infrared optical system 100 for image acquisition provided in Example 8 are shown in Table 8-1.

[0285] Table 8-1. Partial parameters of the far-infrared optical system 100 for image acquisition provided in Example 8

[0286] Effective focal length 19mm F-number 0.9 resolution 640×512 Pixel size 10μm distortion -0.87％ Relative Illuminance ＞94.8％ Total optical length (TTL) 26.212mm Optical Back Focus (BFL) 7.740mm Operating band Far-infrared (8μm-12μm) Maximum field of view (FOV) (2ω) 24.44°

[0287] As shown in Table 8-1, the total optical length and back focal length of the far-infrared optical system 100 used for image acquisition both meet the design specifications. The far-infrared optical system 100 has an F-number of 0.9, which can significantly increase the amount of light entering the far-infrared optical system 100 and collect as much energy as possible from the far-infrared optical system 100 when the image sensor has a low response to light energy, thereby ensuring excellent image quality.

[0288] Starting from object plane 70, along the optical axis 60 from object plane 70 to image plane 80, each surface in the far-infrared optical system 100 used for image acquisition is numbered, and the parameters of each surface are summarized to obtain Table 8-2 below.

[0289] Table 8-2. Parameters of each surface in the far-infrared optical system 100 for image acquisition provided in Example 8

[0290]

[0291] The analysis of each surface in Table 8-2 can be referred to Example 1, and will not be analyzed again in this example.

[0292] Surfaces 1, 2, 4 and 5 are even-order aspherical surfaces, and their surface shapes satisfy equation (12). The values ​​of K, A, B, C, D... of surfaces 1, 2, 4 and 5 can all be found in Table 8-3.

[0293] Table 8-3. Coefficients of even-order aspherical surfaces in the far-infrared optical system 100 for image acquisition provided in Example 8

[0294]

[0295] In this embodiment, the diffractive optical element 30 is a binary diffraction surface, and the coefficients of the binary diffraction surface can be obtained from Table 8-4.

[0296] Table 8-4. Coefficients of the binary diffraction plane in the far-infrared optical system 100 for imaging provided in Example 8

[0297] 2 Binary Diffraction Surface 10.0mm -1.29E+01 -4.58E+01 7.58E+01 -4.79E+01 1.03E+01

[0298] Please see Figure 39 , Figure 39 The MTF field-of-view curve of the far-infrared optical system 100 for image acquisition provided in Embodiment 8 is shown. Figure 39 The horizontal axis in the image represents the image height, and its unit is millimeters. Figure 39 The field of view is measured using image height on the horizontal axis. Figure 39 The vertical axis represents the MTF value. Figure 39 The table lists the sagittal and meridional curves of the MTF at a spatial frequency of 25 lp / mm as a function of the field of view, and the sagittal and meridional curves of the MTF at a spatial frequency of 50 lp / mm as a function of the field of view. Figure 39 It can be seen that the MTF is greater than 0.26 across the entire field of view, indicating that the far-infrared optical system 100 used for image acquisition has extremely high resolution and imaging quality.

[0299] The far-infrared optical system 100 for image acquisition provided in Example 8 has excellent imaging effect with point pattern convergence across the entire field of view.

[0300] Please see Figure 40 , Figure 40 The field curvature diagram of the far-infrared optical system 100 for image acquisition provided in Embodiment 8 is shown. Figure 40 The horizontal axis represents the field curvature, measured in millimeters. Figure 40 The central vertical axis represents the field of view angle, in degrees. Figure 40 The image shows the field curvature of the far-infrared optical system 100 used for imaging under 8-micron, 10-micron, and 12-micron far-infrared light. Figure 40 It can be seen that the far-infrared optical system 100 for image acquisition provided in Example 8 has a meridional field curvature of 0.0064 mm and a sagittal field curvature of 0.1085 mm at the center wavelength (10 micrometers), which is extremely small and has excellent image quality.

[0301] Please see Figure 41 , Figure 41 The distortion diagram of the far-infrared optical system 100 for image acquisition provided in Embodiment 8 is shown. Figure 41 The middle horizontal axis represents the distortion ratio. Figure 41 The central vertical axis represents the field of view angle, in degrees. Figure 41The image shows the distortion of the far-infrared optical system 100 used for imaging under 8-micron, 10-micron, and 12-micron far-infrared light. Due to... Figure 41 The three curves almost overlap, therefore this embodiment does not distinguish between them. Figure 41 As can be seen, the maximum absolute value of distortion is only 0.87%, and the image is almost distortion-free.

[0302] The far-infrared optical system 100 for image acquisition provided in Example 8 has a relative illumination greater than 94.8% across the entire field of view, indicating that its image uniformity is good and the transition from the center to the edge is uniform.

[0303] The far-infrared optical system 100 for image acquisition provided in Example 8 has a maximum vertical chromatic difference of 3.79 micrometers under 8-micrometer, 10-micrometer, and 12-micrometer far-infrared light, which is smaller than the pixel size of 10 micrometers, demonstrating excellent chromatic difference control capability.

[0304] Example 9

[0305] Figure 42 A schematic diagram of the architecture layout of the far-infrared optical system 100 for image acquisition provided in Embodiment 9 is shown. Figure 42 The far-infrared optical system 100 used for image acquisition includes, along the optical axis 60 from the object plane 70 to the image plane 80, the following components in sequence: a first refractive lens 10, a diffractive optical element 30, an aperture 40, a second refractive lens 20, and a protective glass 50. The aperture 40 is located between the first refractive lens 10 and the second refractive lens 20. The diffractive optical element 30 is a binary diffraction surface, and the binary diffraction surface is located on the image side of the first refractive lens 10. The absolute value of the maximum phase difference between the binary diffraction surfaces is... Some parameters of the far-infrared optical system 100 for image acquisition provided in Example 9 are shown in Table 9-1.

[0306] Table 9-1. Partial parameters of the far-infrared optical system 100 for image acquisition provided in Example 9

[0307] Effective focal length 21mm F-number 0.9 resolution 640×512 Pixel size 10μm distortion -0.95％ Relative Illuminance ＞95％ Total optical length (TTL) 29.065mm Optical Back Focus (BFL) 7.750mm Operating band Far-infrared (8μm-12μm) Maximum field of view (FOV) (2ω) 24.40°

[0308] As shown in Table 9-1, the total optical length and back focal length of the far-infrared optical system 100 used for image acquisition both meet the design specifications. The far-infrared optical system 100 has an F-number of 0.9, which can significantly increase the amount of light entering the far-infrared optical system 100 and collect as much energy as possible from the far-infrared optical system 100 when the image sensor has a low response to light energy, thereby ensuring excellent image quality.

[0309] Starting from object plane 70, along the optical axis 60 from object plane 70 to image plane 80, each surface in the far-infrared optical system 100 used for image acquisition is numbered, and the parameters of each surface are summarized to obtain Table 9-2 below.

[0310] Table 9-2. Parameters of each surface in the far-infrared optical system 100 for image acquisition provided in Example 9

[0311]

[0312]

[0313] The analysis of each surface in Table 9-2 can be referred to Example 1, and will not be analyzed again in this example.

[0314] Surfaces 1, 2, 4 and 5 are even-order aspherical surfaces, and their surface shapes satisfy equation (12). The values ​​of K, A, B, C, D... of surfaces 1, 2, 4 and 5 can all be found in Table 9-3.

[0315] Table 9-3. Coefficients of even-order aspherical surfaces in the far-infrared optical system 100 for image acquisition provided in Example 9

[0316]

[0317] In this embodiment, the diffractive optical element 30 is a binary diffraction surface, and the coefficients of the binary diffraction surface can be obtained from Table 9-4.

[0318] Table 9-4. Coefficients of the binary diffraction plane in the far-infrared optical system 100 for imaging provided in Example 9

[0319] 2 Binary Diffraction Surface 12.6mm 1.26E+01 -3.85E+01 2.64E+01 -8.62E+01 1.54E+02

[0320] Please see Figure 43 , Figure 43 The MTF field-of-view curve of the far-infrared optical system 100 for image acquisition provided in Embodiment 9 is shown. Figure 43 The horizontal axis in the image represents the image height, and its unit is millimeters. Figure 43 The field of view is measured using image height on the horizontal axis. Figure 43 The vertical axis represents the MTF value. Figure 43 The table lists the sagittal and meridional curves of the MTF at a spatial frequency of 25 lp / mm as a function of the field of view, and the sagittal and meridional curves of the MTF at a spatial frequency of 50 lp / mm as a function of the field of view. Figure 43 It can be seen that the MTF is greater than 0.31 throughout the entire field of view, indicating that the far-infrared optical system 100 used for image acquisition has extremely high resolution and imaging quality.

[0321] The far-infrared optical system 100 for image acquisition provided in Example 9 has excellent imaging effect with point pattern convergence across the entire field of view.

[0322] Please see Figure 44 , Figure 44 The field curvature diagram of the far-infrared optical system 100 for image acquisition provided in Embodiment 9 is shown. Figure 44 The horizontal axis represents the field curvature, measured in millimeters. Figure 44 The central vertical axis represents the field of view angle, in degrees. Figure 44 The image shows the field curvature of the far-infrared optical system 100 used for imaging under 8-micron, 10-micron, and 12-micron far-infrared light. Figure 44 As can be seen, the far-infrared optical system 100 for image acquisition provided in Example 9 has a meridional field curvature of 0.0404 mm and a sagittal field curvature of 0.0737 mm at the center wavelength (10 micrometers), which is extremely small and has excellent image quality.

[0323] Please see Figure 45 , Figure 45 The distortion diagram of the far-infrared optical system 100 for image acquisition provided in Embodiment 9 is shown. Figure 45 The middle horizontal axis represents the distortion ratio. Figure 45 The central vertical axis represents the field of view angle, in degrees. Figure 45 The image shows the distortion of the far-infrared optical system 100 used for imaging under 8-micron, 10-micron, and 12-micron far-infrared light. Due to... Figure 45 The three curves almost overlap, therefore this embodiment does not distinguish between them. Figure 45 As can be seen, the maximum absolute value of distortion is only 0.95%, and the image is almost distortion-free.

[0324] The far-infrared optical system 100 for image acquisition provided in Example 9 has a relative illumination greater than 95% across the entire field of view, indicating that its image uniformity is good and the transition from the center to the edge is uniform.

[0325] The far-infrared optical system 100 for image acquisition provided in Example 9 has a maximum vertical chromatic difference of 6.576 micrometers under 8-micrometer, 10-micrometer, and 12-micrometer far-infrared light, which is smaller than the pixel size of 10 micrometers, demonstrating excellent chromatic difference control capability.

[0326] After summarizing the parameters of the far-infrared optical system 100 for image acquisition provided in the above nine embodiments, Table 10 is obtained as shown below. The table 10 is mainly used to illustrate that the conditions satisfied by the far-infrared optical system 100 for image acquisition provided in this application have all been verified and supported by experiments.

[0327] Table 10. Parameters of the far-infrared optical system 100 for image acquisition provided in each embodiment

[0328]

[0329]

[0330] This application also provides a far-infrared optical lens, which includes an imaging detector (not shown) and the aforementioned far-infrared optical system 100 for image acquisition. The imaging detector is disposed on the image plane 80 of the far-infrared optical system 100 for image acquisition, and the imaging detector includes, but is not limited to, CMOS (Complementary Metal Oxide Semiconductor) and CCD (Charge Coupled Device).

[0331] Other embodiments of this application will readily occur to those skilled in the art upon consideration of the specification and practice of the utility models disclosed herein. This application is intended to cover any variations, uses, or adaptations of this application that follow the general principles of this application and include common knowledge or customary techniques in the art not disclosed herein. The specification and examples are to be considered exemplary only, and the true scope and spirit of this application are indicated by the appended claims.

Claims

1. A far-infrared optical system for image acquisition, characterized in that, The far-infrared optical system for image acquisition includes: a first refractive lens, a second refractive lens, and a diffractive optical element, wherein the first refractive lens and the second refractive lens are arranged sequentially along the optical axis from the object side to the image side; The paraxial region of the object-side surface of the first refractive lens convexes towards the object side, and the paraxial region of the image-side surface of the first refractive lens convexes towards the object side. The paraxial region of the object-side surface of the second refractive lens convexes towards the object side, and the paraxial region of the image-side surface of the second refractive lens convexes towards the object side; The far-infrared optical system used for image acquisition satisfies: ； ； ； in, Let be the focal length of the first refracting lens. is the focal length of the second refracting lens.

2. The far-infrared optical system for image acquisition according to claim 1, characterized in that, The far-infrared optical system used for image acquisition satisfies: ； in, The aperture number of the far-infrared optical system used for image acquisition. The maximum effective diameter of the first refractive lens is... The total optical length of the far-infrared optical system used for image acquisition is given. Let be the radius of curvature of the object-side surface of the first refractive lens. Let be the radius of curvature of the image-side surface of the first refracting lens. Let be the radius of curvature of the object-side surface of the second refracting lens. Let be the radius of curvature of the image-side surface of the second refracting lens.

3. The far-infrared optical system for image acquisition according to claim 1, characterized in that, The far-infrared optical system used for image acquisition satisfies: ； in, The center thickness of the first refractive lens is [missing information]. The edge thickness of the first refractive lens. The center thickness of the second refractive lens The edge thickness of the second refractive lens.

4. The far-infrared optical system for image acquisition according to claim 1, characterized in that, The far-infrared optical system used for image acquisition satisfies: ； in, The effective focal length of the far-infrared optical system used for image acquisition is... The aperture number of the far-infrared optical system used for image acquisition.

5. The far-infrared optical system for image acquisition according to claim 1, characterized in that, The far-infrared optical system used for image acquisition satisfies: ； in, The total optical length of the far-infrared optical system used for image acquisition is given. The radius of the imaging area on the image plane of the far-infrared optical system used for image acquisition is given.

6. The far-infrared optical system for image acquisition according to claim 1, characterized in that, The far-infrared optical system used for image acquisition satisfies: ； in, The maximum effective diameter of the first refractive lens is... The maximum effective diameter of the second refractive lens is... The maximum field of view of the far-infrared optical system used for image acquisition is denoted as .

7. The far-infrared optical system for image acquisition according to claim 1, characterized in that, The far-infrared optical system used for image acquisition satisfies: ； in, Let be the refractive index of the first refractive lens. The aperture number of the far-infrared optical system used for image acquisition. Let be the radius of curvature of the object-side surface of the first refractive lens. Let be the radius of curvature of the image-side surface of the first refracting lens.

8. The far-infrared optical system for image acquisition according to claim 1, characterized in that, The far-infrared optical system used for image acquisition satisfies: ； in, Let be the sagittal of the object-side surface of the first refracting lens. It is the sagittal height of the image-side surface of the first refracting lens.

9. A far-infrared optical lens, characterized in that, The far-infrared optical lens includes: an imaging detector and a far-infrared optical system for image acquisition as described in any one of claims 1-8; the imaging detector is disposed on the image plane of the far-infrared optical system for image acquisition.

Images