An athermalized super-wide-angle lens

Abstract

The application relates to the technical field of optical lenses, in particular to an athermalized ultra-wide-angle lens, which comprises a lens barrel, a first lens group, a diaphragm and a second lens group which are coaxially arranged in the lens barrel in sequence; from the object side to the image side, the first lens group comprises lens one, lens two, lens three and lens four which are arranged in sequence, and the second lens group comprises lens five, lens six and lens seven which are arranged in sequence; wherein the lens one is a fisheye type meniscus negative lens, and the concave surface is arranged towards the image side; the lens two and the lens three are both meniscus negative lenses, and the concave surfaces are both arranged towards the image side; the lens four is a positive lens; the lens five, the lens six and the lens seven are all positive lenses. The lens provided by the application has a field of view angle of 185 degrees, can fully and without dead angle shoot all objects in front; the aperture value can reach 1.4, can quickly image; and the lens can adapt to an environment with a temperature range of -40 DEG C to 80 DEG C, covers most outdoor temperature environments, and effectively improves the environmental adaptability of the lens.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of optical lenses, in particular to an athermalized ultra-wide-angle lens. BACKGROUND

[0002] In some special application occasions, such as law enforcement and security, artistic creation, sports photography, and VR panoramic content production image collection, which require no dead angle monitoring, an ultra-wide-angle (field of view reaching or exceeding 180 degrees) and imaging fast and stable lens is expected to meet the needs. For an optical system, the larger the field of view, the greater the distortion, and when reaching 180 degrees, the distortion will be 100%, but the distortion only causes the image to deform, and does not affect the clarity of the image. Through software algorithm correction, the distorted image can be restored to the original real image. The existing ultra-wide-angle lens usually has problems such as insufficient field of view, small aperture, poor imaging quality, or difficulty in adapting to large temperature difference environment, which is difficult to meet the increasingly stringent market demand. SUMMARY

[0003] The purpose of the embodiments of the present application is to provide an athermalized ultra-wide-angle lens to solve the problems of insufficient field of view, small aperture, poor imaging quality, or difficulty in adapting to large temperature difference environment of the existing ultra-wide-angle lens.

[0004] In order to achieve the above-mentioned purpose, the present application provides an athermalized ultra-wide-angle lens, which comprises a lens barrel and a first lens group, a diaphragm and a second lens group coaxially arranged in the lens barrel; the first lens group is composed of four lenses, which are in order from the object side to the image side as follows: lens one, lens two, lens three and lens four; wherein the lens one is a fisheye type meniscus negative lens, and the concave surface is arranged towards the image side; the lens two and the lens three are both meniscus negative lenses, and both the concave surfaces are arranged towards the image side; the lens four is a positive lens; the second lens group is composed of three lenses, which are in order from the object side to the image side as follows: lens five, lens six and lens seven, and the lens five, the lens six and the lens seven are all positive lenses.

[0005] In the embodiments of the present application, the lens one is made of high light transmission glass material which is wear-resistant, high-temperature-resistant and heat-insulating.

[0006] In the embodiments of the present application, the lens diameters of the lens one, the lens two and the lens three decrease in order.

[0007] In the embodiments of the present application, the lens four is an asymmetric biconvex positive lens, and the side with larger curvature of the lens surface is arranged towards the object side; the lens four is composed of a meniscus negative lens and a biconvex positive lens.

[0008] In the embodiments of the present application, the lens five is a meniscus positive lens, and the convex surface is arranged towards the image side.

[0009] In the embodiment of the present application, the sixth lens is a biconvex positive lens, and the side with larger curvature is arranged towards the object side, and the sixth lens is composed of a biconvex positive lens and a meniscus negative lens.

[0010] In the embodiment of the present application, the seventh lens is a plano-convex positive lens, and the convex surface of the seventh lens is arranged towards the object side.

[0011] In the embodiment of the present application, the F number of the athermalized ultra-wide-angle lens is in the range of 1.2≤F≤1.4.

[0012] In the embodiment of the present application, the athermalization temperature range of the athermalized ultra-wide-angle lens is -40℃~80℃.

[0013] The scheme provided in the present application has at least the following beneficial effects:

[0014] The field of view of the lens provided in the present application reaches 185°, and all objects in the front can be fully and non-dead-angle photographed; the aperture value can reach 1.4, and fast imaging can be achieved; in addition, the lens can adapt to an environment with a temperature range of -40℃~80℃, covering most outdoor temperature environments, and effectively improving the adaptability of the lens to the environment. While meeting the requirements of large field of view, high-speed imaging and wide-range athermalization, excellent imaging quality is also ensured.

[0015] Other features and advantages of the embodiment of the present application will be described in detail in the subsequent specific implementation manner part. DETAILED DESCRIPTION

[0016] The accompanying drawings are used to provide a further understanding of the embodiments of the present application, and constitute a part of the specification, and are used together with the following specific implementation to explain the embodiments of the present application, but do not constitute a limitation on the embodiments of the present application. In the drawings:

[0017] Figure 1 The structure and distribution of each lens in the athermalized ultra-wide-angle lens are schematically shown;

[0018] Figure 2 The MTF diagram of the athermalized ultra-wide-angle lens in the embodiment of the present application at -40℃ and focusing on infinity is shown;

[0019] Figure 3 The MTF diagram of the athermalized ultra-wide-angle lens in the embodiment of the present application at 20℃ and focusing on infinity is shown;

[0020] Figure 4 The MTF diagram of the athermalized ultra-wide-angle lens in the embodiment of the present application at 80℃ and focusing on infinity is shown;

[0021] Figure 5A spot diagram measured for the athermalized super wide-angle lens in this embodiment when focusing at infinity;

[0022] Figure 6 A lateral chromatic aberration distribution diagram measured for the athermalized super wide-angle lens in this embodiment when focusing at infinity;

[0023] Figure 7 An f-theta distortion diagram measured for the athermalized super wide-angle lens in this embodiment when focusing at infinity.

[0024] BRIEF DESCRIPTION OF DRAWINGS

[0025] 1, lens one; 2, lens two; 3, lens three; 4, lens four; 5, lens five; 6, lens six; 7, lens seven. DETAILED DESCRIPTION

[0026] In order to make the objects, technical solutions and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be described clearly and completely below in conjunction with the drawings in the embodiments of the present application. It should be understood that the specific embodiments described herein are only used to explain and illustrate the embodiments of the present application and should not be used to limit the embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without making creative efforts fall within the scope of protection of the present application.

[0027] It should be noted that if the embodiments of the present application involve directional indications (such as up, down, left, right, front, back, etc.), the directional indications are only used to explain the relative positional relationship, motion condition, etc. between components in a certain posture (as shown in the drawings), and if the certain posture changes, the directional indications also change accordingly.

[0028] In addition, if the embodiments of the present application involve descriptions such as “first”, “second”, etc., the descriptions of “first”, “second”, etc. are only for description purposes and should not be understood as indicating or implying the relative importance of the indicated technical features or implicitly indicating the number of the indicated technical features. Therefore, the features limited by “first”, “second” can explicitly or implicitly include at least one of the features. In addition, the technical solutions of the various embodiments can be combined with each other, but it must be based on the fact that a person of ordinary skill in the art can realize it, and when the combination of technical solutions contradicts each other or cannot be realized, it should be considered that the combination of technical solutions does not exist and is not within the scope of protection claimed by the present application.

[0029] Embodiment 1

[0030] As Figure 1As shown, the embodiment provides athermalized super wide-angle lens, which comprises a lens barrel and a first lens group, a diaphragm and a second lens group coaxially arranged in the lens barrel in sequence; the first lens group comprises four lenses, which are sequentially lens one 1, lens two 2, lens three 3 and lens four 4 from the object side to the image side; wherein the lens one 1 is a fisheye type meniscus negative lens, and the concave surface is arranged towards the image side; the lens two 2 and the lens three 3 are both meniscus negative lenses, and both the concave surfaces are arranged towards the image side; the lens four 4 is a positive lens; the second lens group comprises three lenses, which are sequentially lens five 5, lens six 6 and lens seven 7 from the object side to the image side, and the lens five 5, the lens six 6 and the lens seven 7 are all positive lenses.

[0031] Specifically, the lens one 1 is located at the outermost periphery of the lens on the object side, is made of high light transmission glass material resistant to wear, high temperature and heat insulation (such as high borosilicate glass, quartz glass, etc.), can isolate the internal precision lenses, prevent dust, moisture or touch damage, is placed at the front end, can protect other lenses in the lens system, ensure that the subsequent lens group works in a controlled environment, and effectively provide the adaptability of the entire lens system to the environment. In the embodiment, the diameter of the lens one 1 is greater than 50 mm, and the meniscus lens with the convex surface towards the object side can directly receive light of a field of view greater than 180°, which is the physical basis of the super wide-angle (fisheye) view angle. As the front end lens, its shape can gently introduce the edge light into the lens group, avoiding the large incidence angle of light causing serious aberration or reflection. Its negative focal power can make the light diverge, creating conditions for the relay correction of the subsequent negative lens group (lens two 2 and lens three 3).

[0032] The lens two 2 and the lens three 3 are both meniscus negative lenses, which are used for aberration pre-correction and light angle relay control. The lens two 2 is arranged not far behind the lens one 1, which is used to continue to maintain the negative focal power of the front group and further expand the effective field of view. The curvature of the convex surface of the lens two 2 is smaller than that of the lens one 1 (more flat), which begins to moderate the extreme aberration (especially distortion and spherical aberration) generated by the first lens, so that the incidence angle of the light collected by the lens one 1 becomes gentle, and the light is more orderly guided to the rear. The lens three 3 forms a three-piece negative lens sequence with the previous two lenses, which can sufficiently lengthen the back focal length. After the light passes through the three negative lenses, even the edge light of the extreme field of view (such as 180°), the angle of the light entering the subsequent lens group has become relatively gentle, greatly reducing the correction pressure of the rear group.

[0033] The lens one 1 to the lens three 3, the lens diameter decreases in turn, which ensures that even for the light of the extreme edge field of view, after passing through the edge concave surface of the previous lens, it will not be blocked by the lens frame of the next lens, ensuring the smoothness of the super wide-angle light path.

[0034] The fourth lens 4 is composed of a meniscus negative lens and a biconvex positive lens, and the refractive difference of the cemented surface can be used to eliminate chromatic aberration (especially axial chromatic aberration). The overall lens is a biconvex lens, and the side with larger curvature is arranged towards the object side, that is, the convex surface facing the image side is flatter. This arrangement helps to gently guide the light, leaving room for subsequent aberration correction. After being diverged by the three negative lenses in front, the light needs to be strongly converged to form an image, so the fourth lens 4 starts to provide the positive focal power required by the system. In addition, the negative lens in the cemented lens is often made of special optical materials (such as calcium fluoride CaF2, abnormal dispersion glass, etc.). These materials not only help to correct chromatic aberration, but also have a complementary relationship with the positive lens material in terms of thermal expansion coefficient and refractive index temperature coefficient (dn / dT). By carefully designing the focal power distribution and material matching of the two lenses, the focal position of this combination can be offset with temperature changes.

[0035] The diaphragm is located between the first lens group and the second lens group (behind the fourth lens 4 and in front of the fifth lens 5). By placing the diaphragm at this position, the incident height and angle of the off-axis light (especially the chief ray) in the second lens group can be effectively controlled, thereby optimizing the correction of off-axis aberrations such as coma and astigmatism.

[0036] The fifth lens 5 is a meniscus positive lens, with the convex surface facing the image side. This shape is very effective for correcting astigmatism and field curvature, and it helps to "flatten" the image plane, making the edges and center clear at the same time. It can also continue to correct the residual spherical aberration of the system.

[0037] The sixth lens 6 is also composed of a biconvex positive lens and a meniscus negative lens, and the overall lens is a biconvex positive lens, with the side of larger curvature facing the object side, for fine correction of high-order aberrations and chromatic aberration. The material combination of the sixth lens 6 (for example, the positive lens uses ordinary glass, and the negative lens uses special low dn / dT material) and the focal power distribution are similar to those of the fourth lens 4. The sixth lens 6 works with the fourth lens to ensure that the focal point of the entire optical system drifts very little within a wide temperature range. The seventh lens 7 is a plano-convex positive lens, with the convex surface facing the object side. As the last surface of the system, it is responsible for fine-tuning the remaining aberrations (such as distortion and field curvature). The flat side can be directly close to or attached to the sensor protection glass, so that the chief ray from the lens can be incident vertically to the sensor plane as much as possible, perfectly matching modern digital imaging systems. This can minimize the refraction and reflection of edge light, significantly improving edge image quality and reducing glare.

[0038] The lens provided by the embodiment adopts a reverse telephoto lens structure of "front negative and rear positive", which can achieve a short focal length (a large viewing angle) while providing a long back intercept, and can be adapted to various types of cameras (such as single-lens reflex cameras / mirrorless cameras), effectively expanding the application range of the lens. By reasonably distributing aberrations, gradually shrinking the light beam and eliminating aberrations, the tolerance sensitivity of the optical lens is effectively reduced. In addition, unlike the traditional reverse telephoto structure, in the embodiment, the diaphragm is not located on the boundary line between the "positive lens" and the "negative lens", but is located behind the fourth lens (positive lens), which aims to control the chief ray angle, optimize distortion and astigmatism, and correct large aberrations. For fisheye lenses with more than 180°, the aberrations generated by the front negative group are disastrous and nonlinear. If a completely symmetrical "negative-diaphragm-positive" layout is adopted, the positive lens group in the rear may need extremely high curvature and complexity to resist the aberrations of the front group (which is difficult to achieve in the process). Moving the diaphragm backward essentially breaks the symmetry of the structure, allowing the rear positive group to have stronger positive refractive power and more lenses (the fourth lens to the seventh lens are all part of the rear positive group), so that the aberrations generated by the front group can be more finely and more effectively corrected step by step.

[0039] Embodiment 2

[0040] In the embodiment, the F number of the athermalized ultra-wide-angle lens ranges from 1.2 to 1.4, which can quickly image and is suitable for high-speed cameras.

[0041] In addition, in order to adapt to the complex outdoor environment with varying temperatures, the athermalized ultra-wide-angle lens provided by the embodiment is a passive athermalized lens, which does not need to be refocused in a temperature range of -40°C to 80°C, and can adapt to occasions with large environmental changes.

[0042] For example, the materials of the lens barrel, the first lens to the seventh lens can refer to Table 1:

[0043] Table 1

[0044] Lens No. Material No. 1 H-LAK53A 2 H-ZF62 3 H-K9L 4a H-ZF62 4b H-ZF88 5 H-FK95 6a H-LAK10 6b H-ZF96 7 H-PK3 Lens Barrel Aluminum Alloy

[0045] In Table 1, the lens numbers 1-3, 5 and 7 correspond to the first lens 1, the second lens 2, the third lens 3, the fifth lens 5 and the seventh lens 7, respectively, 4a corresponds to the meniscus negative lens constituting the fourth lens 4, 4b corresponds to the biconvex positive lens constituting the fourth lens 4, 6a corresponds to the biconvex positive lens constituting the sixth lens 6, and 6b corresponds to the meniscus negative lens constituting the sixth lens 6.

[0046] For example, Table 2 shows the basic parameters of each lens element in a heat-free ultra-wide-angle lens, where the units for radius of curvature and air gap are millimeters (mm). It should be noted that all radii of curvature (the larger the radius of curvature, the smaller the curvature), lens center thickness, and air gap in the table are normalized values, and the sign of the radius of curvature value only indicates the direction, not the magnitude. The value is positive when the lens surface is curved towards the image side, and negative when the lens surface is curved towards the object side.

[0047] Table 2

[0048] Lens Surface No. Curvature Radius Air Gap / Glass Center Thickness Refractive Index Abbe Number S1 18.622 1.62 1.8348 49.366 S2 8.589 5.85 1.0000 0 (Air) S3 34.924 1.08 1.8040 46.574 S4 5.096 8.63 1.0000 0 (Air) S5 30.987 0.86 1.6385 55.446 S6 3.883 2.57 1.0000 0 (Air) S7 9.128 0.86 1.8040 46.574 S8 3.419 1.36 1.7408 27.760 S9 -21.061 2.77 1.0000 0 (Air) S10 (Diaphragm) Inf 1.51 1.0000 0 (Air) S11 -18.588 1.00 1.4970 81.605 S12 -5.317 0.11 1.0000 0 (Air) S13 10.584 1.33 1.6230 58.120 S14 -5.074 0.65 1.9459 17.941 S15 -31.949 0.11 1.0000 0 (Air) S16 5.909 1.13 1.5928 68.642 S17 Inf 5.15 1.0000 0 (Air)

[0049] In Table 2, the lens surface serial numbers S1~S18 and Figure 1 The numbers S1 to S18 in the table correspond to the following: S10 represents the aperture stop; the air gap / glass center thickness value corresponding to S1 indicates the gap between S1 and S2, i.e., the (center) thickness of lens 1; the refractive index corresponding to S1 is the refractive index of the object between S1 and S2, i.e., the refractive index of lens 1; the Abbe number corresponding to S1 is the Abbe number of the object between S1 and S2, i.e., the Abbe number of lens 1. The air gap / glass center thickness value corresponding to S2 indicates the gap between S2 and S3, i.e., the air gap between lens 1 and lens 2; the corresponding refractive index and Abbe number for S2 are the refractive index and Abbe number of air. The explanations of the values ​​corresponding to the other lens surface numbers in the table can be found in the [reference needed]. Figure 1 And so on, without going into further detail here.

[0050] This embodiment also verifies the imaging effect of the athermalized ultra-wide-angle lens designed based on the above data, and obtains the following results through imaging analysis: Figure 2~Figure 4 The MTF chart shown is as follows: Figure 5 The image point diffusion pattern shown is as follows: Figure 6 The color difference distribution diagram shown and as follows Figure 7 The distortion diagram shown.

[0051] Figure 2~Figure 4 These figures represent the MTF (Mean Transformation Factor) charts of an athermal ultra-wide-angle lens at -40℃, 20℃, and 80℃ when focused at infinity. The MTF value describes the lens's efficiency in transferring object-side contrast to the image-side (0~100%). The horizontal axis represents spatial frequency: unit lp / mm (line pairs / millimeter), indicating the number of black and white line pairs per millimeter; the vertical axis represents the MTF value: 0~1 (or 0%~100%), with higher values ​​indicating a closer approximation to ideal imaging. Figure 2For example, there are numerous color curves in the figure, in which the solid line represents the MTF curve measured in the tangential (sagittal) direction on the image plane, the dashed line represents the MTF curve measured in the meridional (radial) direction on the image plane, the black solid line in the figure corresponds to "Diff. Limit-Tangential" indicates the theoretical upper limit curve of the performance of the ideal optical system (only subject to physical diffraction limitation) in the tangential direction; the black dashed line in the figure corresponds to "Diff. Limit-Sagittal" indicates the theoretical upper limit curve of the performance of the ideal optical system (only subject to physical diffraction limitation) in the meridional direction; the green dashed line corresponds to "17.00 (deg)-Sagittal" indicates the MTF curve measured in the meridional (radial) direction at a field angle of 17 degrees; the red solid line corresponds to "17.00 (deg)-Sagittal" indicates the MTF curve measured in the tangential (tangential) direction at a field angle of 27 degrees. Other in turn, not described here. Reference Figure 2~Figure 4 In the temperature range of -40℃~80℃, the overall MTF curve does not fluctuate greatly, and maintains a high (OTF) value at both low frequency (10 lp / mm) and high frequency (30 lp / mm), i.e. the athermalized ultra-wide-angle lens provided in this embodiment has a wide temperature range of athermalization performance and superior imaging capability.

[0052] Figure 5 The image point spot diagram measured by the athermalized ultra-wide-angle lens when focusing on infinity, wherein the horizontal and vertical coordinate axes of the 10 image point spot sub-diagrams (a~j) shown have units of μm (the maximum coordinate scale is 20 μm), representing the size of the image point spot diagram. Figure 5 (a) represents the image point spot diagram measured at the center of the (image plane center) sensor imaging center position, and the view shows a circular spot, indicating that the center imaging effect of the microscope lens is excellent, sharp and without chromatic aberration; Figure 5 (b) represents the image point spot diagram measured at a distance of 0.551mm from the (image plane center) sensor imaging center position, at a field angle of 17 degrees, Figure 5 (c)~ Figure 5 (j) the corresponding numerical explanation can be combined with Figure 5 (b) by analogy, not described here. Figure 5 The field angle position sampled in Figure 2~Figure 4 The field angle position sampled in Figure 5 The image point spot diagrams shown in each sub-diagram in can directly show the change in the imaging effect of the lens from the center of the image plane to the edge and when the field angle gradually increases.Figure 5 The root mean square radius and the geometric radius corresponding to each subgraph diffraction spot are shown in Table 3 as follows:

[0053] Table 3

[0054] Subfigure No. RMS Radius (μm) Geometric Radius (μm) a 1.825 3.254 b 2.052 4.111 c 2.380 4.464 d 2.614 4.924 e 2.649 4.930 f 2.455 4.933 g 2.310 4.949 h 2.203 5.172 i 2.148 5.249 j 2.167 5.208

[0055] As shown in Table 3, the difference between the root mean square radius and the geometric radius of each diffraction spot is substantially between 2-3 μm, that is, the stray light is effectively suppressed at each field point, the lens does not have obvious defects that cause light scattering, and the lens has sharp and high-resolution imaging capability.

[0056] Figure 6 The chromatic aberration distribution graph can intuitively reflect the axial chromatic aberration of the athermalized ultra-wide-angle lens. The abscissa represents the focal point offset (unit: μm), and the ordinate represents the wavelength (unit: μm). This graph represents the axial offset of each wavelength of light relative to the Wavelength=0.5573 μm (reference wavelength) focal point (zero point) when the image plane is fixed at Focus=9.222 mm, from 0.486 μm (F light, blue) to 0.6563 μm (C light, red) in the continuous waveband. 0.486 μm-0.6563 μm almost completely covers the most sensitive visible light spectrum of the human eye, and is also the core response range of most color imaging sensors (CMOS / CCD). As can be seen from the graph, the focal point offset corresponding to the light of this range of wavelengths is within ±10 μm, which means that the lens system has excellent chromatic aberration correction performance.

[0057] Figure 7 The f-theta distortion graph of the athermalized ultra-wide-angle lens provided in this embodiment when focusing on infinity is shown. The abscissa is the distortion rate, and the ordinate is the field of view angle. The formula for calculating the distortion rate is: distortion rate = [(actual image height-ideal image height) / ideal image height] x 100%. If it is positive, it is pincushion distortion (image convex outward), and if it is negative, it is barrel distortion (image concave inward). As can be seen from the graph, Figure 7 It can be seen that the distortion rate is controlled within 7% in the field of view angle range of 92.5°, which is lower than the distortion rate allowable range (within 8%) of the fisheye lens, and meets the expected standard.

[0058] It should also be noted that the terms "comprising", "including", or any other variant thereof are intended to cover non-exclusive inclusions, so that processes, methods, articles, or devices that include a series of elements not only include those elements, but also include other elements not explicitly listed, or inherent to such processes, methods, articles, or devices. Without more limitations, the element defined by the statement "including a" does not exclude the presence of additional identical elements in the process, method, article, or device including the element.

[0059] The above merely provides an example of the present application, but is not intended to limit the present application. The present application can have various modifications and changes for those skilled in the art. Any modification, equivalent replacement, improvement, etc. within the spirit and principle of the present application shall be included in the scope of claims of the present application.

Claims

1. An athermalized ultra-wide-angle lens characterized in that, The athermalized super-wide-angle lens is composed of a lens barrel and a first lens group, a diaphragm and a second lens group arranged coaxially in the lens barrel in sequence; the first lens group comprises four lenses arranged in sequence from an object side to an image side as a first lens (1), a second lens (2), a third lens (3) and a fourth lens (4); wherein the first lens (1) is a fisheye type meniscus negative lens with a concave surface facing the image side; the second lens (2) and the third lens (3) are both meniscus negative lenses with concave surfaces facing the image side; the fourth lens (4) is an asymmetric biconvex positive lens with a side of larger curvature facing the object side; the fourth lens (4) is composed of a meniscus negative lens and a biconvex positive lens bonded together; the second lens group comprises three lenses arranged in sequence from the object side to the image side as a fifth lens (5), a sixth lens (6) and a seventh lens (7), and the fifth lens (5), the sixth lens (6) and the seventh lens (7) are all positive lenses.

2. The athermalized ultra-wide-angle lens according to claim 1, characterized in that, The first lens (1) is made of a high-transmittance glass material resistant to wear, high temperature and heat insulation.

3. The athermalized ultra-wide-angle lens of claim 1, wherein The diameters of the first lens (1), the second lens (2) and the third lens (3) are sequentially decreased.

4. The athermalized ultra-wide-angle lens of claim 1, wherein The fifth lens (5) is a meniscus positive lens with a convex surface facing the image side.

5. The athermalized ultra-wide-angle lens of claim 1, wherein, The sixth lens (6) is a biconvex positive lens with a side of larger curvature facing the object side, and the sixth lens (6) is composed of a biconvex positive lens and a meniscus negative lens bonded together.

6. The athermalized ultra-wide-angle lens of claim 1, wherein, The seventh lens (7) is a plano-convex positive lens with a convex surface facing the object side.

7. The athermalized ultra-wide-angle lens of claim 1, wherein The F number of the athermalized super-wide-angle lens is in the range of 1.2≤F≤1.

4.

8. The athermalized ultra-wide-angle lens of claim 1, wherein, The athermalization temperature range of the athermalized super-wide-angle lens is -40℃~80℃.

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