Far infrared optical system and far infrared optical lens

Abstract

The utility model discloses a far-infrared optical system and a far-infrared optical lens. The far-infrared optical system sequentially comprises a super lens and a refraction lens from an object side to an image side along an optical axis, the focal power of the super lens is positive, and the effective refractive index neff of the super lens is more than 1 and less than 12; the surface, close to the object side, of the refraction lens protrudes towards the image side, and the surface, close to the image side, of the refraction lens protrudes towards the image side. And the focal power phi 2 of the refraction lens is more than 0.3 mm <-1 > and less than 1mm <-1 >. According to the far infrared optical system, the super lens performs aberration compensation on the refraction lens, so that the far infrared optical system has better imaging quality. The super lens is processed through a semiconductor technology, the processing technology is compatible with an existing semiconductor processing technology, and the super lens has good machinability. By reasonably distributing the focal power of the refraction lens, the refraction lens also has good machinability, that is, the far infrared optical system provided by the utility model has good machinability on the premise of having better imaging quality.

Description

Technical Field

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

[0002] Far-infrared optical systems offer the advantage of all-weather imaging. While some existing systems offer excellent imaging quality, they suffer from irrational optical power distribution. Some lenses have excessive focal lengths, which in turn makes processing these lenses more difficult and results in lower yields, hindering mass production of these systems. Utility Model Content

[0003] In response to the above technical problems, the embodiments of the present application provide a far-infrared optical system and a far-infrared optical lens, aiming to provide a far-infrared optical system and a far-infrared optical lens with good processability while having better imaging quality.

[0004] According to one aspect of the embodiment of the present application, a far-infrared optical system is disclosed, wherein the far-infrared optical system comprises, in order from the object side to the image side along the optical axis: a super lens and a refractive lens; the optical power of the super lens is positive, and the equivalent refractive index n of the super lens is eff Satisfy: 1<n eff <12; the refractive lens is a positive lens, the surface of the refractive lens close to the object side is convex to the image side, and the surface of the refractive lens close to the image side is convex to the image side; the optical power Φ2 of the refractive lens satisfies: 0.3mm -1 <Φ2<1.0mm -1 .

[0005] In some embodiments, the refractive lens is a spherical lens.

[0006] In some embodiments, the far-infrared optical system satisfies: Wherein, the Δλ is the difference between the maximum working wavelength and the minimum working wavelength of the far-infrared optical system, is the phase of the metalens, and x is the distance between any point on the metalens and the center of the metalens.

[0007] In some embodiments, the far-infrared optical system satisfies: Wherein, T2 is the center thickness of the refractive lens, R1 is the curvature radius of the surface of the refractive lens close to the object side, and R2 is the curvature radius of the surface of the refractive lens close to the image side.

[0008] In some embodiments, the far-infrared optical system satisfies: Wherein, the TTL is the total optical length of the far-infrared optical system, and the T 12 is the thickness of the air gap between the metalens and the refractive lens on the optical axis.

[0009] In some embodiments, the far-infrared optical system satisfies: Wherein, L is the distance between the phase inflection point of the metalens and the center of the metalens, and r m is the effective radius of the metalens.

[0010] In some embodiments, the far-infrared optical system satisfies: Among them, f is the effective focal length of the far-infrared optical system, T2 is the center thickness of the refractive lens, F# is the aperture number of the far-infrared optical system, and R1 is the curvature radius of the surface of the refractive lens close to the object side.

[0011] In some embodiments, the far-infrared optical system further comprises an aperture, wherein the aperture is disposed on the object side of the superlens;

[0012] or,

[0013] The aperture is provided on a surface of the metalens close to the object side;

[0014] or,

[0015] The aperture is provided on the surface of the super lens close to the image side;

[0016] or,

[0017] The aperture is arranged between the super lens and the refractive lens.

[0018] A second aspect of an embodiment of the present application provides a far-infrared optical lens, which includes: an imaging detector and a far-infrared optical system as described above; the imaging detector is arranged on the image plane of the far-infrared optical system.

[0019] In some embodiments, the far-infrared optical lens further includes a lens barrel and an adhesive, the lens barrel being provided with a mounting through hole, the far-infrared optical system being accommodated in the mounting through hole, and the adhesive being arranged corresponding to at least one of the metalens and the refractive lens to seal at least one axial end of the mounting through hole.

[0020] In some embodiments, the mounting through hole includes a first hole segment, a second hole segment, and a third hole segment that are sequentially connected, the diameter of the first hole segment is larger than the diameter of the second hole segment, and the diameter of the second hole segment is larger than the diameter of the third hole segment;

[0021] At least a portion of the refractive lens is accommodated in the second hole segment, and at least a portion of the refractive lens is located in the first hole segment; the adhesive is disposed in a first gap between the refractive lens and the hole wall of the first hole segment; the super lens is accommodated in the first hole segment;

[0022] The far-infrared optical lens further includes a pressure cover, which is provided with a first light-transmitting hole. The axial direction of the first light-transmitting hole is arranged along the optical axis. The pressure cover is located on a side of the superlens away from the refractive lens, and the pressure cover is connected to the lens barrel.

[0023] In some embodiments, the far-infrared optical lens further comprises a first sealing member, and a receiving groove is provided at one end of the lens barrel close to the gland;

[0024] The pressure cover is covered on the lens barrel, and one end of the pressure cover close to the lens barrel is received in the receiving groove. A second gap is defined between the pressure cover and the groove wall of the receiving groove, and the first sealing member fills the second gap.

[0025] In some embodiments, the mounting through hole includes a fourth hole segment, a fifth hole segment, and a sixth hole segment that are sequentially connected, the diameter of the fourth hole segment is smaller than the diameter of the fifth hole segment, and the diameter of the fifth hole segment is smaller than the diameter of the sixth hole segment;

[0026] The super lens is accommodated in the fifth hole segment; at least a portion of the refractive lens is accommodated in the fifth hole segment, and at least a portion of the refractive lens is located in the sixth hole segment, and the adhesive is arranged in a third gap between the refractive lens and the inner wall of the sixth hole segment.

[0027] In some embodiments, the far-infrared optical lens further includes a second sealing member, the second sealing member is provided with a second light-transmitting hole, and the axial direction of the second light-transmitting hole is arranged along the optical axis;

[0028] The second sealing member is located on a side of the super lens away from the refractive lens, and the second sealing member abuts against the lens barrel.

[0029] The far-infrared optical system provided by the present application includes: a super lens and a refractive lens in order from the object side to the image side along the optical axis. The optical power of the super lens is positive, and the equivalent refractive index n of the super lens is eff Satisfy: 1<n eff <12. The refractive lens is a positive lens. The surface of the refractive lens close to the object side is convex to the image side. The surface of the refractive lens close to the image side is convex to the image side. The optical power Φ2 of the refractive lens meets the following requirements: 0.3mm -1 <Φ2<1.0mm -1. In the present application, the metalens compensates for the aberration of the refractive lens so that the far-infrared optical system has better imaging quality. The metalens is processed by semiconductor technology, and its processing technology is compatible with existing semiconductor processing technology. The metalens has good machinability. By reasonably allocating the optical focal length of the refractive lens, the refractive lens also has good machinability. That is, the far-infrared optical system provided by the present application has good machinability while having better imaging quality. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] The above and other objects, features and advantages of the present application will become more apparent by describing in detail example embodiments thereof with reference to the attached drawings.

[0031] Figure 1 A schematic diagram of the architecture layout of a far-infrared optical system in one embodiment of the present application is shown.

[0032] Figure 2 FIG. 4 shows a phase distribution diagram of a metalens in an embodiment of the present application.

[0033] Figure 3 The figure shows the MTF field of view curve of the far-infrared optical system in one embodiment of the present application.

[0034] Figure 4 A field curvature diagram of a far-infrared optical system in an embodiment of the present application is shown.

[0035] Figure 5 A vertical axis chromatic aberration curve of a far-infrared optical system in an embodiment of the present application is shown.

[0036] Figure 6 A schematic diagram of the architecture layout of a far-infrared optical system in one embodiment of the present application is shown.

[0037] Figure 7 The figure shows the MTF field of view curve of the far-infrared optical system in one embodiment of the present application.

[0038] Figure 8 A field curvature diagram of a far-infrared optical system in an embodiment of the present application is shown.

[0039] Figure 9 A vertical axis chromatic aberration curve of a far-infrared optical system in an embodiment of the present application is shown.

[0040] Figure 10 A schematic diagram of the architecture layout of a far-infrared optical system in one embodiment of the present application is shown.

[0041] Figure 11 The figure shows the MTF field of view curve of the far-infrared optical system in one embodiment of the present application.

[0042] Figure 12A field curvature diagram of a far-infrared optical system in an embodiment of the present application is shown.

[0043] Figure 13 A vertical axis chromatic aberration curve of a far-infrared optical system in an embodiment of the present application is shown.

[0044] Figure 14 A schematic structural diagram of a far-infrared optical lens in one embodiment of the present application is shown.

[0045] Figure 15 A schematic structural diagram of a far-infrared optical lens in one embodiment of the present application is shown.

[0046] Reference numerals

[0047] 100. Far infrared optical system;

[0048] 1. Superlens; 11. Substrate; 12. Micro-nanostructure;

[0049] 2. Refractive lens;

[0050] 3. Aperture;

[0051] 4. Protective parts;

[0052] A, object plane; B, image plane; S, optical axis;

[0053] 200, lens barrel; 2001, mounting through hole; 2001a, first hole segment; 2001b, second hole segment; 2001c, third hole segment; 2001d, fourth hole segment; 2001e, fifth hole segment; 2001f, sixth hole segment; 2002, receiving groove;

[0054] G1, first gap; G2, second gap; G3, preset gap; G4, third gap;

[0055] 300, gland; 300a, first light-transmitting hole;

[0056] 400, second sealing member; 400a, second light-transmitting hole;

[0057] 1000. Far-infrared optical lens. DETAILED DESCRIPTION

[0058] Example embodiments will now be described more fully with reference to the accompanying drawings. However, example embodiments can be implemented in a variety of forms and should not be construed as limited to the examples set forth herein; rather, these example embodiments are provided so that the description of this application will be more comprehensive and complete and will fully convey the concepts of the example embodiments to those skilled in the art. The accompanying drawings are merely schematic illustrations of the present application and are not necessarily drawn to scale. Identical reference numerals in the figures indicate identical or similar parts, and thus repeated descriptions thereof will be omitted.

[0059] In addition, the described features, structures or characteristics can be combined in one or more example embodiments in any suitable manner. In the following description, many specific details are provided to provide a full understanding of the example embodiments of the present application. However, those skilled in the art will appreciate that the technical solutions of the present application can be practiced while omitting one or more of the specific details, or other modules, components, etc. can be adopted. In other cases, known structures, methods, implementations or operations are not shown or described in detail to avoid obscuring the main content and making various aspects of the present application vague.

[0060] See also Figure 1 , Figure 1 FIG1 shows a schematic diagram of the structure layout of the optical system in one embodiment of the present application, wherein the optical axis S is the center line of the light beam. Figure 1 In the figure, the object to be measured is located to the left of the leftmost lens, that is, the object side is located to the left of the leftmost lens, and object plane A is located on the object side. The image formed by the optical system is located to the right of the rightmost lens, that is, the image side is located to the right of the rightmost lens, and image plane B is located on the image side. Therefore, the direction from object plane A to image plane B along the optical axis S is the same as the direction from the object side to the image side along the optical axis S.

[0061] The far-infrared optical system 100 includes a super lens 1 and a refractive lens 2 , which are sequentially arranged along the optical axis S from the object side to the image side.

[0062] The optical power of the metalens 1 is positive. The metalens 1 includes a substrate 11 and a micro-nanostructure 12. The micro-nanostructure 12 is provided on the surface of the substrate 11 close to the object side and / or the surface of the substrate 11 close to the image side. According to the phase modulation method adopted, the corresponding phase modulation formula can be adaptively used to configure the various parameters of the micro-nanostructure 12, so that the metalens 1 can achieve the corresponding optical performance. The equivalent refractive index n of the metalens 1 is eff Satisfy: 1<n eff <12, so that the superlens 1 has the expected deflection ability for far-infrared light.

[0063] The refractive lens 2 is a positive lens. The surface of the refractive lens 2 close to the object side is convex to the image side. The surface of the refractive lens 2 close to the image side is convex to the image side. The optical power Φ2 of the refractive lens 2 satisfies: 0.3mm -1 <Φ2<1.0mm -1 , so that the refractive lens 2 has an expected optical focal length and good processability.

[0064] In this application, the metalens 1 compensates for the aberrations of the refractive lens 2, thereby enabling the far-infrared optical system 100 to have superior imaging quality. The metalens 1 is fabricated using a semiconductor process compatible with existing semiconductor processing techniques, resulting in excellent machinability. By rationally allocating the optical power of the refractive lens 2, the refractive lens 2 also exhibits excellent machinability. In other words, the far-infrared optical system 100 provided by this application exhibits excellent machinability while maintaining superior imaging quality.

[0065] In some embodiments, the focal length Φ2 of the refractive lens 2 further satisfies: 0.5 mm -1 <Φ2<0.6mm -1 , so that the actual optical focal length of the far-infrared optical system 100 is more matched with the target optical focal length of the far-infrared optical system 100, and at the same time, the refractive lens 2 still has good machinability.

[0066] In some embodiments, the equivalent refractive index n of the metalens 1 is eff Further satisfy: 1<n eff <6, so that the deflection of far-infrared light by the superlens 1 is more precise.

[0067] In some embodiments, the micro-nano structure 12 is disposed on a surface of the substrate 11 close to the object side.

[0068] In some embodiments, the surface of the substrate 11 close to the object side and the surface of the substrate 11 close to the image side are both provided with micro-nano structures 12, so that the metalens 1 has a higher degree of design freedom.

[0069] In some embodiments, the micro-nanostructure 12 is a positive micro-nanostructure 12 .

[0070] In some embodiments, the micro-nanostructure 12 is a negative micro-nanostructure 12 .

[0071] In some embodiments, the micro-nano structure 12 is provided with a layer to make the processing technology of the superlens 1 compatible with the existing semiconductor processing technology, which can facilitate the processing and manufacturing of the superlens 1.

[0072] In some embodiments, the micro-nanostructure 12 has two or more layers, so that the metalens 1 has a larger and expected optical focal length.

[0073] For the metalens 1 , the position of the micro-nanostructure 12 , the positive and negative orientation of the micro-nanostructure 12 , and the number of layers of the micro-nanostructure 12 can be freely combined, as long as the metalens 1 has the expected performance.

[0074] In some embodiments, the specific structure of the metalens 1 is as follows: the micro-nanostructure 12 is provided on the image-side surface of the substrate 11, and the micro-nanostructure 12 is a negative micro-nanostructure 12. Furthermore, the micro-nanostructure 12 is provided in only one layer. This ensures that the metalens 1 has good processability while also having the desired optical power. It should be noted that this is for illustrative purposes only and should not be construed as limiting the specific structure of the metalens 1.

[0075] In some embodiments, the refractive lens 2 is an aspheric lens, so that the far-infrared optical system 100 has better performance in aberration control, thereby improving the imaging quality of the far-infrared optical system 100 to a certain extent.

[0076] In some embodiments, the refractive lens 2 is a spherical lens, which helps to further reduce the production cost of the far-infrared optical system 100 .

[0077] In some embodiments, the far-infrared optical system 100 satisfies Conditional Formula 1: Among them, f m is the focal length of the super lens 1, and f is the effective focal length of the far-infrared optical system 100. m , f have the same dimension, both are length units, such as millimeters.

[0078] Conditional equation 1 represents the ratio of the focal length of the metalens 1 to the effective focal length of the far-infrared optical system. Conditional equation 1 shows that the optical focal length provided by the metalens 1 in the far-infrared optical system 100 is much smaller than the optical focal length of the far-infrared optical system 100. The main function of the metalens 1 is to provide aberration compensation within the entire field of view. The upper limit of conditional equation 1 is used to ensure that the metalens 1 has a minimum optical focal length that meets the requirements, thereby completing light adjustment within the system length and ensuring that the metalens 1 can provide aberration compensation capabilities. The lower limit of conditional equation 1 prevents the optical focal length provided by the metalens 1 from being too large. If the optical focal length provided by the metalens 1 is too large, it will cause overcompensation and introduce significant dispersion. In other words, the lower limit of conditional equation 1 is used to ensure that the optical focal length provided by the metalens 1 meets the requirements and does not introduce significant dispersion, which is beneficial for controlling the aberrations of the far-infrared optical system 100.

[0079] In some embodiments, the far-infrared optical system 100 satisfies Conditional Formula 2: Wherein, Δλ is the difference between the maximum operating wavelength and the minimum operating wavelength of the far-infrared optical system 100. x is the distance between any point on the metalens 1 and the center of the metalens 1, and dx represents the change in the distance between any point on the metalens 1 and the center of the metalens 1. dx and Δλ have the same dimension, both being units of length, such as millimeters.

[0080] is the phase of superlens 1, represents the phase change of the superlens 1, The unit of is rad, and the unit of "2πrad" in conditional equation 2 is also rad. Since the focal lengths provided by the metalens 1 for light of different wavelengths are slightly different, the larger the Δλ, the greater the negative chromatic aberration brought by the metalens 1 with the same coefficient. is the maximum value of the phase gradient of the structural surface of the metalens 1, where To control the aberration of the far-infrared optical system 100 , the phase distribution slope of the structural surface of the metalens 1 must satisfy Condition 2, reflecting the magnitude of the negative chromatic aberration introduced by the structural surface of the metalens 1. The upper limit of Condition 2 ensures that the positive chromatic aberration introduced by the refractive lens 2 can be compensated by the metalens 1, while the lower limit of Condition 2 prevents the metalens 1 from introducing significant chromatic aberration and causing overcompensation.

[0081] In some embodiments, the far-infrared optical system 100 satisfies Condition 3: Wherein, T2 is the central thickness of refractive lens 2, that is, the thickness of refractive lens 2 along optical axis S. R1 is the radius of curvature of the object-side surface of refractive lens 2. R2 is the radius of curvature of the image-side surface of refractive lens 2. T2, R1, and R2 have the same dimension, all in units of length, such as millimeters.

[0082] The upper limit of Conditional Formula 3 prevents the refractive lens 2 from being too thick, which would increase the material cost of the lens. The lower limit of Conditional Formula 3 ensures that the refractive lens 2 has an appropriate thickness and curvature, thereby making the refractive lens 2 well-manufacturable while also ensuring that the refractive lens 2 has a certain optical power.

[0083] In some embodiments, the far-infrared optical system 100 satisfies Condition 4: Wherein, EPD (Entrance Pupil Diameter, abbreviated as EPD) is the entrance pupil diameter of far-infrared optical system 100, and r2 is the effective radius of the image-side surface of refractive lens 2. In this application, the effective radius refers to the radius of the maximum light transmission area of ​​the surface corresponding to the lens. EPD and r2 have the same dimension, both in length units, such as millimeters.

[0084] The value of conditional expression 4 can directly affect the aperture of the far-infrared optical system 100. Limiting it within the range of 0.95 to 1.1 helps to constrain the aperture of the far-infrared optical system 100, avoid the radial dimension of the far-infrared optical system 100 from being too large, and enable the far-infrared optical system 100 to have a smaller volume.

[0085] In some embodiments, the far-infrared optical system 100 satisfies Condition 5: Wherein, TTL (Total Track Length, abbreviated as TTL) is the total optical length of the far-infrared optical system 100. In this application, TTL is the distance from the surface of the metalens 1 close to the object side to the image plane B on the optical axis S. 12 is the thickness of the air gap between the metalens 1 and the refractive lens 2 on the optical axis S. TTL, T 12 have the same dimension, both are units of length, such as millimeters.

[0086] The value of Conditional Expression 5 represents the ratio of the total optical length to the thickness of the air gap between metalens 1 and refractive lens 2. The upper limit of Conditional Expression 5 prevents excessive air gap thickness, leaving adequate space for metalens 1 and refractive lens 2. It also ensures an appropriate optical back focal length, facilitating assembly of far-infrared optical system 100. The lower limit of Conditional Expression 5 ensures appropriate spacing between the lenses, making far-infrared optical system 100 easier to assemble.

[0087] In some embodiments, the far-infrared optical system 100 satisfies Conditional Formula 6: Wherein, L is the distance between the phase inflection point of the superlens 1 and the center of the superlens 1. The phase inflection point of the superlens 1 is the point where the monotonicity of the phase of the superlens 1 changes within the range from the center of the superlens 1 to the edge of the superlens 1. m is the effective radius of the metalens 1, r m , L have the same dimension, both are units of length, such as millimeters.

[0088] In the far-infrared optical system 100, the aberration correction capabilities required for the central field of view and the peripheral field of view are different, and the magnitude of the aberration caused by the center and the peripheral of the refractive lens 2 is also different. Therefore, the phase of the metalens 1 does not change monotonically. Figure 2 , Figure 2 shows a phase distribution diagram of the metalens 1 in one embodiment of the present application, Figure 2 The horizontal axis is the distance between any point on the metalens 1 and the center of the metalens 1, and its unit is millimeter; Figure 2 The vertical axis represents the phase, and its unit is 2πrad. Figure 2 It can be seen that the monotonicity of the metalens' phase changes at point P, which is the phase inflection point. The phase gradients on both sides of the phase inflection point P of the metalens 1 are different, allowing the metalens 1 to correct aberrations within different ranges. The range of conditional equation 6 can effectively balance aberrations in the central and peripheral fields of view, thereby improving the imaging quality of the far-infrared optical system 100.

[0089] In some embodiments, the far-infrared optical system 100 satisfies Condition 7: Wherein, f is the effective focal length of far-infrared optical system 100, T2 is the center thickness of refractive lens 2, F# is the aperture number of far-infrared optical system 100, also known as the F-number, and R1 is the radius of curvature of the object-side surface of refractive lens 2. f, T2, and R1 have the same dimension, i.e., units of length, such as millimeters.

[0090] Conditional Formula 7 limits the amount of light entering the far-infrared optical system 100, so that the far-infrared optical system 100 has a sufficient light aperture. At the same time, it can also avoid excessive absorption of far-infrared light due to the refractive lens 2 being too thick. If the refractive lens 2 absorbs too much far-infrared light, the far-infrared light reaching the image plane B will be reduced. That is, Conditional Formula 7 can also ensure that there is sufficient incident light on the image plane B of the far-infrared optical system 100, so that the image formed by the far-infrared optical system has higher brightness and higher relative illumination.

[0091] In some embodiments, the far-infrared optical system 100 further includes an aperture 3, which is used to control the amount of light entering the far-infrared optical system 100 to ensure that the far-infrared optical system 100 can work effectively and generate high-quality images.

[0092] In some embodiments, the far-infrared optical system 100 further includes an aperture 3 , which is disposed on the object side of the superlens 1 , that is, the aperture 3 is located on the side of the superlens 1 away from the refractive lens 2 , and there is a preset distance between the aperture 3 and the superlens 1 .

[0093] In some embodiments, the aperture 3 is disposed on the surface of the superlens 1 close to the object side, that is, the aperture 3 is disposed on the front surface of the superlens 1 .

[0094] In some embodiments, the aperture 3 is disposed on the surface of the superlens 1 close to the image side, that is, the aperture 3 is disposed on the front surface of the superlens 1 .

[0095] In some embodiments, the aperture 3 is disposed between the metalens 1 and the refractive lens 2 .

[0096] In a preferred embodiment, the aperture 3 is disposed between the metalens 1 and the refractive lens 2 so that the far-infrared optical system 100 has an expected amount of light input, thereby ensuring that the infrared optical system 100 can work effectively and generate high-quality images.

[0097] In some embodiments, the far-infrared optical system 100 further includes a protective member 4 for protecting each lens. The protective member 4 is permeable to far-infrared light and is located on the side of the refractive lens 2 facing away from the metalens 1. The protective member 4 includes, but is not limited to, protective glass.

[0098] The present application illustratively provides three far-infrared optical systems 100 that meet usage requirements in three embodiments. Next, the far-infrared optical systems 100 provided in each embodiment of the present application are introduced in detail.

[0099] Example 1

[0100] Figure 1 FIG. 1 shows a schematic diagram of the architecture layout of the far-infrared optical system 100 provided in Example 1. Figure 1 The mid- and far-infrared optical system 100 comprises, in order from object plane A to image plane B along the optical axis S: a metalens 1, an aperture 3, a refractive lens 2, and a protective member 4. The aperture 3 is located on the image-side surface of the metalens 1, the refractive lens 2 is a spherical lens, and the protective member 4 is a protective glass. Some parameters of the far-infrared optical system 100 provided in Example 1 are shown in Table 1.

[0101] Table 1. Partial parameters of the far-infrared optical system 100 provided in Example 1

[0102] parameter data Total optical length (TTL) 4.38mm Maximum field of view (2ω) 64° F-number 0.95 Effective focal length 1.59mm Working band Far infrared (8um-12um)

[0103] As shown in Table 1, the far-infrared optical system 100 has a relatively short total optical length of only 4.38 mm. Therefore, the far-infrared optical system 100 provided in Example 1 is relatively compact. The far-infrared optical system 100 has an F-number of 0.95, which significantly increases the amount of light entering the far-infrared optical system 100. Furthermore, even when the image sensor has a low response to light energy, the system maximizes the amount of energy entering the far-infrared optical system 100, thereby ensuring excellent imaging quality.

[0104] Starting from the object plane A, along the optical axis S from the object plane A to the image plane B, starting from the surface of the metalens 1 close to the object side, each surface in the far-infrared optical system 100 is numbered, and the parameters of each surface are summarized to obtain the following Table 2.

[0105] Table 2. Parameters of various surfaces in the far-infrared optical system 100 provided in Example 1

[0106] Surface serial number Surface type Curvature radius (mm) Thickness (mm) Material 1 spherical surface unlimited 0.3 silicon 2 Structural surface-aperture unlimited 0.49 - 3 spherical surface -5.7 1.55 silicon 4 spherical surface -2.9 1.4 - 5 spherical surface unlimited 0.5 silicon 6 spherical surface unlimited 0.1 - 7 spherical surface unlimited - -

[0107] For each surface in Table 2, surface 1 is the surface of the metalens 1 near the object side, and surface 2 is the surface of the metalens 1 near the image side. Since the micro-nanostructure 12 is provided on surface 2 and the aperture 3 is located on surface 2, surface 2 is denoted as structure surface-aperture 3. Surface 3 is the surface of the refractive lens 2 near the object side, and surface 4 is the surface of the refractive lens 2 near the image side. Surface 5 is the surface of the protective member 4 near the object side, and surface 6 is the surface of the protective member 4 near the image side. Surface 7 is image plane B.

[0108] As shown in Table 2, the radius of curvature of surface 1 is infinite, meaning that surface 1 is flat. The distance between surface 1 and surface 2 is 0.3 mm, and the material between surfaces 1 and 2 is silicon. The radius of curvature of surface 2 is infinite, meaning that surface 2 is flat. The distance between surface 2 and surface 3 is 0.49 mm, and the material between surfaces 2 and 3 is air. The radius of curvature of surface 3 is -5.7 mm, the distance between surface 3 and surface 4 is 1.55 mm, and the material between surfaces 3 and 4 is silicon. The radius of curvature of surface 4 is -2.9 mm, the distance between surface 4 and surface 5 is 1.4 mm, and the material between surfaces 4 and 5 is air. The radius of curvature of surface 5 is infinite, meaning that surface 5 is flat. The distance between surface 5 and surface 6 is 0.5 mm, and the material between surface 5 and surface 6 is silicon. The radius of curvature of surface 6 is infinite, meaning that surface 6 is flat. The distance between surface 6 and surface 7 is 0.1 mm, and the material between surface 6 and surface 7 is air.

[0109] See also Figure 3 , Figure 3 The MTF (Modulation Transfer Function, MTF for short) field of view curve of the far-infrared optical system 100 provided in Example 1 is shown. Figure 3 The horizontal axis is the X-axis field of view angle, and its unit is degree. Figure 3 The vertical axis is the MTF value. Figure 3 The figure lists the sagittal curve S1 and meridional curve T1 of the MTF with 10lp / mm spatial frequency as it changes with the field of view, the sagittal image curve S2 and meridional image curve T2 of the MTF with 21lp / mm spatial frequency as it changes with the field of view, and the sagittal image curve S3 and meridional image curve T3 of the MTF with 42lp / mm spatial frequency as it changes with the field of view. Figure 3 It can be seen that within the 0.9 field of view (28.8°), the MTF is greater than 0.3, and within the 1.0 field of view (32°), the MTF is greater than 0.2, indicating that the far-infrared optical system 100 has excellent imaging quality.

[0110] See also Figure 4 , Figure 4 : shows the field curvature diagram of the far-infrared optical system 100 provided in Example 1, Figure 4 The horizontal axis is the field curvature, and its unit is millimeters. Figure 4 The vertical axis is the field of view angle, and its unit is degree. Figure 4S1 is the field curvature of far-infrared light with a wavelength of 8 microns in the sagittal direction, and T1 is the field curvature of far-infrared light with a wavelength of 8 microns in the meridional direction; S2 is the field curvature of far-infrared light with a wavelength of 9 microns in the sagittal direction, and T2 is the field curvature of far-infrared light with a wavelength of 9 microns in the meridional direction; S3 is the field curvature of far-infrared light with a wavelength of 10 microns in the sagittal direction, and T3 is the field curvature of far-infrared light with a wavelength of 10 microns in the meridional direction; S4 is the field curvature of far-infrared light with a wavelength of 11 microns in the sagittal direction, and T4 is the field curvature of far-infrared light with a wavelength of 11 microns in the meridional direction; S5 is the field curvature of far-infrared light with a wavelength of 12 microns in the sagittal direction, and T5 is the field curvature of far-infrared light with a wavelength of 12 microns in the meridional direction. Figure 4 It can be seen that the maximum field curvature of the far-infrared optical system 100 in the sagittal direction is 0.0577 mm, and the maximum field curvature of the far-infrared optical system 100 in the meridional direction is 0.1025 mm, which meets the requirements for field curvature in the excellent imaging quality standard.

[0111] See also Figure 5 , Figure 5 The vertical axis chromatic aberration diagram of the far-infrared optical system 100 provided in Example 1 under far-infrared light with wavelengths of 8 microns, 9 microns, 10 microns, 11 microns and 12 microns is shown. Figure 5 The horizontal axis is the position of light of different wavelengths on the vertical axis image plane B, and the unit is millimeter. Figure 5 The vertical axis is the field of view angle, and its unit is degree. Figure 5 A total of 5 curves are shown, among which the M curve at 0 microns is the far-infrared light with a wavelength of 8 microns. Since the other 4 curves are too close together, the other 4 curves are not distinguished. Figure 5 It can be seen that within the full field of view, the maximum vertical chromatic aberration is about 0.2 microns, the chromatic aberration is small, and the dispersion is not obvious, meeting the chromatic aberration requirements of the excellent imaging quality standard.

[0112] Example 2

[0113] Figure 6 FIG. 1 shows a schematic diagram of the architecture layout of the far-infrared optical system 100 provided in Example 2. Figure 6 The mid- and far-infrared optical system 100 comprises, in order from object plane A to image plane B along the optical axis S, a metalens 1, an aperture 3, a refractive lens 2, and a protective member 4. The refractive lens 2 is a spherical lens, the aperture 3 is located on the image-side surface of the metalens 1, and the protective member 4 is a protective glass. Table 3 shows some parameters of the far-infrared optical system 100 provided in Example 2.

[0114] Table 3. Partial parameters of the far-infrared optical system 100 provided in Example 2

[0115] parameter data Total optical length (TTL) 4.42mm Maximum field of view (2ω) 74.4° F-number 0.95 Effective focal length 1.62mm Working band Far infrared (8um-12um)

[0116] As shown in Table 3, the far-infrared optical system 100 has a relatively short total optical length of only 4.42 mm. Therefore, the far-infrared optical system 100 provided in Example 2 is relatively compact. The far-infrared optical system 100 has an F-number of 0.95, which significantly increases the amount of light entering the far-infrared optical system 100. Furthermore, even when the image sensor has a low response to light energy, the system collects as much energy as possible, thereby ensuring excellent imaging quality.

[0117] Starting from the object plane A, along the optical axis S from the object plane A to the image plane B, starting from the surface of the metalens 1 close to the object side, each surface in the far-infrared optical system 100 is numbered, and the parameters of each surface are summarized to obtain the following Table 4.

[0118] Table 4. Parameters of various surfaces in the far-infrared optical system 100 provided in Example 2

[0119] Surface serial number Surface type Curvature radius (mm) Thickness (mm) Material 1 spherical surface unlimited 0.3 silicon 2 Structural surface-aperture unlimited 0.49 - 3 spherical surface -5.6 1.55 silicon 4 spherical surface -2.9 1.4 - 5 spherical surface unlimited 0.5 silicon 6 spherical surface unlimited 0.1 - 7 spherical surface unlimited - -

[0120] The analysis of each surface in Table 4 can be referred to Example 1 and will not be repeated here.

[0121] See also Figure 7 , Figure 7 FIG. 2 shows the MTF field curve of the far-infrared optical system 100 provided in Example 2. Figure 7 The horizontal axis is the X-axis field of view angle, and its unit is degree. Figure 7 The vertical axis is the MTF value. Figure 7 The figure lists the sagittal curve S1 and meridional curve T1 of the MTF with 10lp / mm spatial frequency as it changes with the field of view, the sagittal image curve S2 and meridional image curve T2 of the MTF with 21lp / mm spatial frequency as it changes with the field of view, and the sagittal image curve S3 and meridional image curve T3 of the MTF with 42lp / mm spatial frequency as it changes with the field of view. Figure 7 It can be seen that within the 0.9 field of view (33.48°), the MTF is greater than 0.2, and the imaging quality of the far-infrared optical system 100 is relatively good.

[0122] See also Figure 8 , Figure 8 : shows a field curvature diagram of the far-infrared optical system 100 provided in Example 2, Figure 8 The horizontal axis is the field curvature, and its unit is millimeters. Figure 8 The vertical axis is the field of view angle, and its unit is degree. Figure 8S1 is the field curvature of far-infrared light with a wavelength of 8 microns in the sagittal direction, and T1 is the field curvature of far-infrared light with a wavelength of 8 microns in the meridional direction; S2 is the field curvature of far-infrared light with a wavelength of 9 microns in the sagittal direction, and T2 is the field curvature of far-infrared light with a wavelength of 9 microns in the meridional direction; S3 is the field curvature of far-infrared light with a wavelength of 10 microns in the sagittal direction (since the S2 curve and the S3 curve almost completely overlap, the S2 curve and the S3 curve are not distinguished), and T3 is the field curvature of far-infrared light with a wavelength of 10 microns in the meridional direction (since the T2 curve and the T3 curve almost completely overlap, the T2 curve and the T3 curve are not distinguished); S4 is the field curvature of far-infrared light with a wavelength of 11 microns in the sagittal direction, and T4 is the field curvature of far-infrared light with a wavelength of 11 microns in the meridional direction; S5 is the field curvature of far-infrared light with a wavelength of 12 microns in the sagittal direction, and T5 is the field curvature of far-infrared light with a wavelength of 12 microns in the meridional direction. Figure 8 It can be seen that the maximum field curvature of the far-infrared optical system 100 in the sagittal direction is 0.0537 mm, and the maximum field curvature of the far-infrared optical system 100 in the meridional direction is 0.0869 mm, which meet the requirements for field curvature in the excellent imaging quality standard.

[0123] See also Figure 9 , Figure 9 The vertical axis chromatic aberration diagram of the far-infrared optical system 100 provided in Example 2 under far-infrared light with wavelengths of 8 microns, 9 microns, 10 microns, 11 microns and 12 microns is shown. Figure 9 The horizontal axis is the position of light of different wavelengths on the vertical axis image plane B, and the unit is millimeter. Figure 9 The vertical axis is the field of view angle, and its unit is degree. Figure 9 The M curve in the figure is far infrared light with a wavelength of 10 microns. Figure 9 A total of 5 curves are shown, among which the M curve at 0 microns is the far-infrared light with a wavelength of 8 microns. Since the other 4 curves are too close together, the other 4 curves are not distinguished. Figure 9 It can be seen that within the full field of view, the maximum vertical chromatic aberration is about 0.2 microns, the chromatic aberration is small, and the dispersion is not obvious, meeting the chromatic aberration requirements of the excellent imaging quality standard.

[0124] Example 3

[0125] Figure 10 FIG. 1 shows a schematic diagram of the architecture layout of the far-infrared optical system 100 provided in Example 3. Figure 10 The mid- and far-infrared optical system 100 comprises, in order from object plane A to image plane B along the optical axis S, a metalens 1, an aperture 3, a refractive lens 2, and a protective member 4. The refractive lens 2 is a spherical lens, the aperture 3 is located on the image-side surface of the metalens 1, and the protective member 4 is a protective glass. Table 5 shows some parameters of the far-infrared optical system 100 provided in Example 3.

[0126] Table 5. Some parameters of the far-infrared optical system 100 provided in Example 3

[0127]

[0128]

[0129] As shown in Table 5, the far-infrared optical system 100 has a relatively short total optical length of only 4.53 mm. Therefore, the far-infrared optical system 100 provided in Example 3 is relatively compact. The far-infrared optical system 100 has an F-number of 0.95, which significantly increases the amount of light entering the far-infrared optical system 100. Furthermore, even when the image sensor has a low response to light energy, the system collects as much energy as possible, thereby ensuring excellent imaging quality.

[0130] Starting from the object plane A, along the optical axis S from the object plane A to the image plane B, starting from the surface of the metalens 1 close to the object side, each surface in the far-infrared optical system 100 is numbered, and the parameters of each surface are summarized to obtain the following Table 6.

[0131] Table 6. Parameters of various surfaces in the far-infrared optical system 100 provided in Example 3

[0132] Surface serial number Surface type Curvature radius (mm) Thickness (mm) Material 1 spherical surface unlimited 0.3 silicon 2 Structural surface-aperture unlimited 0.51 - 3 spherical surface -6.4 1.62 silicon 4 spherical surface -3.1 1.5 - 5 spherical surface unlimited 0.5 silicon 6 spherical surface unlimited 0.1 - 7 spherical surface unlimited - -

[0133] The analysis of each surface in Table 6 can be referred to Example 1 and will not be repeated here.

[0134] See also Figure 11 , Figure 11 FIG. 1 shows the MTF field curve of the far-infrared optical system 100 provided in Example 3. Figure 11 The horizontal axis is the field of view angle, and its unit is degree. Figure 11 The vertical axis is the MTF value. Figure 11 The figure lists the sagittal curve S1 and meridional curve T1 of the MTF with 10lp / mm spatial frequency as it changes with the field of view, the sagittal image curve S2 and meridional image curve T2 of the MTF with 21lp / mm spatial frequency as it changes with the field of view, and the sagittal image curve S3 and meridional image curve T3 of the MTF with 42lp / mm spatial frequency as it changes with the field of view. Figure 11 It can be seen that within the range of 0.8 field of view (29.6°), the MTF is greater than 0.3, and the imaging quality of the far-infrared optical system 100 is relatively good.

[0135] See also Figure 12 , Figure 12 : shows a field curvature diagram of the far-infrared optical system 100 provided in Example 3, Figure 12 The horizontal axis is the field curvature, and its unit is millimeters. Figure 12The vertical axis is the field of view angle, and its unit is degree. Figure 12 S1 is the field curvature of far-infrared light with a wavelength of 8 microns in the sagittal direction, and T1 is the field curvature of far-infrared light with a wavelength of 8 microns in the meridional direction; S2 is the field curvature of far-infrared light with a wavelength of 9 microns in the sagittal direction, and T2 is the field curvature of far-infrared light with a wavelength of 9 microns in the meridional direction; S3 is the field curvature of far-infrared light with a wavelength of 10 microns in the sagittal direction, and T3 is the field curvature of far-infrared light with a wavelength of 10 microns in the meridional direction; S4 is the field curvature of far-infrared light with a wavelength of 11 microns in the sagittal direction (since the S3 curve and the S4 curve almost completely overlap, the S3 curve and the S4 curve are not distinguished), and T4 is the field curvature of far-infrared light with a wavelength of 11 microns in the meridional direction (since the T3 curve and the T4 curve almost completely overlap, the T3 curve and the T4 curve are not distinguished); S5 is the field curvature of far-infrared light with a wavelength of 12 microns in the sagittal direction, and T5 is the field curvature of far-infrared light with a wavelength of 12 microns in the meridional direction. Figure 12 It can be seen that the maximum field curvature of the far-infrared optical system 100 in the sagittal direction is 0.0563 mm, and the maximum field curvature of the far-infrared optical system 100 in the meridional direction is 0.0919 mm, which meets the requirements for field curvature in the excellent imaging quality standard.

[0136] See also Figure 13 , Figure 13 The vertical axis chromatic aberration diagram of the far-infrared optical system 100 provided in Example 3 under far-infrared light with wavelengths of 8 microns, 9 microns, 10 microns, 11 microns and 12 microns is shown. Figure 13 The horizontal axis is the position of light of different wavelengths on the vertical axis image plane B, and the unit is millimeter. Figure 13 The vertical axis is the field of view angle, and its unit is degree. Figure 13 The M curve in the figure is far infrared light with a wavelength of 10 microns. Figure 13 A total of 5 curves are shown, among which the M curve at 0 microns is the far-infrared light with a wavelength of 8 microns. Since the other 4 curves are too close together, the other 4 curves are not distinguished. Figure 13 It can be seen that within the full field of view, the maximum vertical chromatic aberration is about 0.2 microns, the chromatic aberration is small, and the dispersion is not obvious, meeting the chromatic aberration requirements of the excellent imaging quality standard.

[0137] After summarizing the various parameters of the far-infrared optical system 100 provided by the above three embodiments, the following Table 7 is obtained. Table 7 is mainly used to illustrate that the various conditions met by the far-infrared optical system 100 provided by this application are all verified and supported by experiments.

[0138] Table 7. Parameters of the far-infrared optical system 100 provided in various embodiments

[0139]

[0140]

[0141] See also Figure 14 The present application also provides a far-infrared optical lens 1000, which includes an imaging detector (not shown) and the above-mentioned far-infrared optical system 100. The imaging detector is disposed on the image plane B of the far-infrared optical system 100, and includes, but is not limited to, a CMOS (Complementary Metal Oxide Semiconductor) and a CCD (Charge Coupled Device).

[0142] See also Figure 14 In some embodiments, the far-infrared optical lens 1000 further includes a lens barrel 200 and an adhesive member (not shown). The lens barrel 200 is generally cylindrical and has a mounting hole 2001 defined therein. The mounting hole 2001 is axially aligned with the axial direction of the far-infrared optical system 100 and provides a mounting space for the far-infrared optical system 100. The far-infrared optical system 100 is accommodated in the mounting hole 2001.

[0143] The adhesive member is provided corresponding to at least one of the metalens 1 and the refractive lens 2. The adhesive member is used to fill the gap between the lens and the lens barrel 200 to seal at least one axial end of the mounting through hole 2001, thereby improving the sealing performance of the far-infrared optical lens 1000, reducing the probability of dust and water vapor entering the interior of the lens barrel 200 to a certain extent, and expanding the scope of application of the far-infrared optical lens 1000, so that the far-infrared optical lens 1000 can also be used in humid and / or dusty environments.

[0144] See also Figure 14 In some embodiments, the mounting through hole 2001 includes a first hole segment 2001a, a second hole segment 2001b, and a third hole segment 2001c that are sequentially connected along the optical axis S, wherein the diameter of the first hole segment 2001a is larger than the diameter of the second hole segment 2001b, and the diameter of the second hole segment 2001b is larger than the diameter of the third hole segment 2001c. Therefore, the second hole segment 2001b and the third hole segment 2001c together form a step structure.

[0145] The diameter of refractive lens 2 matches the diameter of second hole segment 2001b. At least a portion of refractive lens 2 is accommodated in second hole segment 2001b, and at least a portion of refractive lens 2 is located in first hole segment 2001a. Because the diameter of first hole segment 2001a is larger than that of refractive lens 2, a first gap G1 is formed between refractive lens 2 and the wall of first hole segment 2001a. An adhesive is disposed in first gap G1 to fill the first gap G1, thereby filling the first gap G1 between refractive lens 2 and the wall of first hole segment 2001a. The adhesive includes, but is not limited to, adhesives, caulking agents, and the like.

[0146] The diameter of the super lens 1 matches the diameter of the first hole section 2001 a , and the super lens 1 is accommodated in the first hole section 2001 a .

[0147] The far-infrared optical lens 1000 further includes a pressure cap 300, which is provided with a first light-transmitting hole 300a. The first light-transmitting hole 300a is axially arranged along the optical axis S, so that light can enter the lens barrel 200 through the first light-transmitting hole 300a. The pressure cap 300 is located on the side of the metalens 1 facing away from the refractive lens 2. The pressure cap 300 is connected to the lens barrel 200 and abuts the metalens 1. Since the surface of the metalens 1 is flat, the pressure cap 300 can be tightly fitted with the metalens 1 to seal the gap at one axial end of the mounting through-hole 2001.

[0148] In the present application, a sealed space is formed between the pressure cover 300 and the adhesive component in the mounting through hole 2001 of the lens barrel 200 of the far-infrared optical lens 1000, which can reduce the entry of dust and water vapor into the sealed space, so that the far-infrared optical lens 1000 has good sealing performance.

[0149] See also Figure 14 In some embodiments, a preset gap G3 is provided between the superlens 1 and the hole wall of the first hole segment 2001a, and a first adhesive is also filled between the superlens 1 and the hole wall of the first hole segment 2001a to seal the preset gap G3 between the superlens 1 and the lens barrel 200, thereby further improving the sealing performance of the far-infrared optical lens 1000.

[0150] See also Figure 14 In some embodiments, a receiving groove 2002 is provided at one end of the lens barrel 200 near the gland 300. The receiving groove 2002 is annular. The gland 300 covers one end of the lens barrel 200 and is received in the receiving groove 2002 at the end of the gland 300 near the lens barrel 200. A second gap G2 is defined between the gland 300 and the receiving groove 2002.

[0151] The far-infrared optical lens 1000 further includes a first sealing member (not shown), which is received in the second gap G2 to fill the second gap G2, thereby improving the sealing performance between the gland 300 and the lens barrel 200, and further improving the sealing performance of the far-infrared optical system 100. The first sealing member includes, but is not limited to, a sealing ring, a sealing gasket, an adhesive, a caulking agent, etc.

[0152] See also Figure 15 The present application also provides a lens barrel 200 of another structure, and both ends of the far-infrared optical lens 1000 along the optical axis S direction using the lens barrel 200 are also sealed.

[0153] See also Figure 15 In some embodiments, the far-infrared optical lens 1000 further includes a lens barrel 200 and an adhesive member (not shown). The lens barrel 200 is generally cylindrical and has a mounting hole 2001 defined therein. The mounting hole 2001 is axially aligned with the axial direction of the far-infrared optical system 100 and provides a mounting space for the far-infrared optical system 100. The far-infrared optical system 100 is accommodated in the mounting hole 2001.

[0154] The adhesive member is provided corresponding to at least one of the metalens 1 and the refractive lens 2. The adhesive member is used to fill the gap between the lens and the lens barrel 200 to seal at least one axial end of the mounting through hole 2001, thereby improving the sealing performance of the far-infrared optical lens 1000, reducing the probability of dust and water vapor entering the interior of the lens barrel 200 to a certain extent, and expanding the scope of application of the far-infrared optical lens 1000, so that the far-infrared optical lens 1000 can also be used in humid and / or dusty environments.

[0155] See also Figure 15 In some embodiments, the mounting through hole 2001 includes a fourth hole segment 2001d, a fifth hole segment 2001e, and a sixth hole segment 2001f, which are sequentially connected along the optical axis S. The diameter of the fourth hole segment 2001d is smaller than the diameter of the fifth hole segment 2001e. Therefore, the fourth hole segment 2001d and the fifth hole segment 2001e together form a stepped structure. The diameter of the fifth hole segment 2001e is smaller than the diameter of the sixth hole segment 2001f.

[0156] The diameter of the metalens 1 matches the diameter of the fifth hole segment 2001e, and the metalens 1 is accommodated in the fifth hole segment 2001e. Because both sides of the metalens 1 along the optical axis S are flat, the metalens 1 fits tightly against the lens barrel 200. The fourth hole segment 2001d and the fifth hole segment 2001e together form a stepped structure that prevents the metalens 1 from moving away from the refractive lens 2, thereby securing the metalens 1. Furthermore, the metalens 1 fits tightly against the lens barrel 200, sealing the gap at one axial end of the mounting through-hole 2001.

[0157] At least a portion of refractive lens 2 is received within fifth hole segment 2001e, and at least a portion of refractive lens 2 is located within sixth hole segment 2001f. Because the diameter of sixth hole segment 2001f is larger than that of refractive lens 2, a third gap G4 is formed between refractive lens 2 and the wall of sixth hole segment 2001f. An adhesive is disposed in third gap G4 to fill it, thereby sealing the gap at the other axial end of mounting through-hole 2001.

[0158] It should be noted that when sealing the third gap G4 , the refractive lens 2 may be pressed in the direction from the refractive lens 2 to the superlens 1 along the optical axis S to provide a pre-tightening force, thereby allowing the superlens 1 to fit the lens barrel 200 .

[0159] This application utilizes the flat nature of the metalens 1. By tightly fitting the metalens 1 to the lens barrel 200, the gap at one end of the far-infrared optical lens 1000 can be sealed without the use of adhesives, for example. The gap at the other end of the far-infrared optical lens 1000 can then be sealed by filling it with adhesive. During installation, only the other end of the far-infrared optical lens 1000 needs to be filled with adhesive, resulting in simple operation and high installation efficiency.

[0160] See also Figure 15 Furthermore, in some embodiments, the far-infrared optical lens 1000 also includes a second seal 400, and the second seal 400 is provided with a second light-transmitting hole 400a. The axial direction of the second light-transmitting hole 400a is arranged along the optical axis S, and the light passing through the fourth hole segment 2001d can be incident on the superlens 1 through the second light-transmitting hole 400a.

[0161] The second seal 400 is located on the side of the metalens 1 away from the refractive lens 2 and abuts against the lens barrel 200. The second seal 400 forms a buffer between the metalens 1 and the lens barrel 200. This allows the refractive lens 2 to apply a greater preload force to the metalens 1 and the second seal 400, thereby improving the sealing of one end of the far-infrared optical lens 1000 and achieving better sealing performance for the far-infrared optical lens 1000. The second seal 400 includes, but is not limited to, a sealing ring and a sealing gasket.

[0162] Those skilled in the art will readily appreciate other embodiments of the present application after considering the specification and practicing the utility model disclosed herein. This application is intended to cover any variations, uses, or adaptations of the present application that follow the general principles of the present application and include common knowledge or customary techniques in the art not disclosed herein. The description and examples are to be considered merely as exemplary, and the true scope and spirit of the present application are indicated by the appended claims.

Claims

1. A far-infrared optical system, characterized in that: The far-infrared optical system includes: a super lens and a refractive lens in sequence from the object side to the image side along the optical axis; the optical power of the super lens is positive, and the equivalent refractive index n of the super lens is eff Satisfy: 1<n eff <12; the refractive lens is a positive lens, the surface of the refractive lens close to the object side is convex to the image side, and the surface of the refractive lens close to the image side is convex to the image side; the focal power Φ2 of the refractive lens satisfies: 0.3mm -1 <Φ2<1.0mm -1 .

2. The far-infrared optical system according to claim 1, characterized in that: The refractive lens is a spherical lens.

3. The far-infrared optical system according to claim 1 or 2, characterized in that: The far-infrared optical system meets the following requirements: Wherein, Δλ is the difference between the maximum working wavelength and the minimum working wavelength of the far-infrared optical system, is the phase of the superlens, and x is the distance between any point on the superlens and the center of the superlens.

4. The far-infrared optical system according to claim 1 or 2, characterized in that: The far-infrared optical system meets the following requirements: Wherein, T2 is the central thickness of the refractive lens, R1 is the curvature radius of the surface of the refractive lens close to the object side, and R2 is the curvature radius of the surface of the refractive lens close to the image side.

5. The far-infrared optical system according to claim 1 or 2, characterized in that: The far-infrared optical system meets the following requirements: Wherein, the TTL is the total optical length of the far-infrared optical system, and the T 12 is the thickness of the air gap between the superlens and the refractive lens on the optical axis.

6. The far-infrared optical system according to claim 1 or 2, characterized in that: The far-infrared optical system meets the following requirements: Wherein, L is the distance between the phase inflection point of the superlens and the center of the superlens, and r m is the effective radius of the superlens.

7. The far-infrared optical system according to claim 1 or 2, characterized in that: The far-infrared optical system meets the following requirements: Among them, f is the effective focal length of the far-infrared optical system, T2 is the center thickness of the refractive lens, F# is the aperture number of the far-infrared optical system, and R1 is the curvature radius of the surface of the refractive lens close to the object side.

8. The far-infrared optical system according to claim 1 or 2, characterized in that: The far-infrared optical system further comprises an aperture, which is arranged on the object side of the super lens; or, The aperture is arranged on a surface of the superlens close to the object side; or, The aperture is arranged on a surface of the super lens close to the image side; or, The aperture is disposed between the super lens and the refractive lens.

9. A far-infrared optical lens, characterized in that: include: An imaging detector and a far-infrared optical system as claimed in any one of claims 1 to 8; The imaging detector is arranged on the image plane of the far-infrared optical system.

10. The far-infrared optical lens according to claim 9, characterized in that: The far-infrared optical lens also includes a lens barrel and an adhesive. The lens barrel is provided with a mounting through hole. The far-infrared optical system is accommodated in the mounting through hole. The adhesive is arranged corresponding to at least one of the super lens and the refractive lens to seal at least one axial end of the mounting through hole.

11. The far-infrared optical lens according to claim 10, characterized in that: The mounting through hole comprises a first hole segment, a second hole segment and a third hole segment which are connected in sequence, the diameter of the first hole segment is larger than the diameter of the second hole segment, and the diameter of the second hole segment is larger than the diameter of the third hole segment; At least a portion of the refractive lens is received in the second hole segment, and at least a portion of the refractive lens is located in the first hole segment; the adhesive is disposed in a first gap between the refractive lens and a hole wall of the first hole segment; the super lens is received in the first hole segment; The far-infrared optical lens also includes a pressure cover, which is provided with a first light-transmitting hole. The axial direction of the first light-transmitting hole is arranged along the optical axis. The pressure cover is located on a side of the superlens away from the refractive lens, and the pressure cover is connected to the lens barrel.

12. The far-infrared optical lens according to claim 11, characterized in that: The far-infrared optical lens further comprises a first sealing member, and a receiving groove is provided at one end of the lens barrel close to the gland; The pressure cover is covered on the lens barrel, and one end of the pressure cover close to the lens barrel is received in the receiving groove. A second gap is formed between the pressure cover and the groove wall of the receiving groove, and the first sealing member fills the second gap.

13. The far-infrared optical lens according to claim 10, characterized in that: The mounting through hole comprises a fourth hole segment, a fifth hole segment and a sixth hole segment which are connected in sequence, the diameter of the fourth hole segment is smaller than the diameter of the fifth hole segment, and the diameter of the fifth hole segment is smaller than the diameter of the sixth hole segment; The super lens is accommodated in the fifth hole segment; at least a portion of the refractive lens is accommodated in the fifth hole segment, and at least a portion of the refractive lens is located in the sixth hole segment, and the adhesive is arranged in a third gap between the refractive lens and the inner wall of the sixth hole segment.

14. The far-infrared optical lens according to claim 13, characterized in that: The far-infrared optical lens further comprises a second sealing member, the second sealing member is provided with a second light-transmitting hole, and the axial direction of the second light-transmitting hole is arranged along the optical axis; The second sealing member is located on a side of the super lens away from the refractive lens, and the second sealing member abuts against the lens barrel.

Images