Large-zoom-ratio long-wave infrared continuous zooming optical lens and electronic equipment

Abstract

The invention discloses a large-zoom-ratio long-wave infrared continuous zooming optical lens and electronic equipment. The lens sequentially comprises a first fixed group, a zooming group, a compensation group, a second fixed group and a focusing group from an object side to an image side. When the lens changes from the short focus to the long focus, the first fixed group and the second fixed group are fixed, the zoom group moves towards the direction close to the image side, the compensation group moves towards the direction away from the image side, and the zoom ratio is 9 times. At the short focus end, the distance between the zooming group and the compensation group is the largest, and the distance between the zooming group and the target surface is the largest; at the long focus end, the distance between the zooming group and the compensation group is minimum, and the distance between the zooming group and the target surface is minimum; wherein the first fixed group comprises a positive lens; wherein the zoom group is composed of two negative lenses; wherein the compensation group is composed of a positive lens; wherein the second fixed group is composed of a negative lens; wherein the focusing group is composed of a positive lens. According to the long-wave infrared continuous zooming system, five-component zooming is adopted, so that the imaging performance of high resolution and wide zoom ratio is achieved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of zoom optical lenses, in particular to a large- zoom-ratio long-wave infrared continuous zoom optical lens and an electronic device. BACKGROUND

[0002] The long-wave infrared continuous zoom optical lens has a large zoom ratio and is widely used in key fields such as military reconnaissance, astronomical observation, and remote sensing detection. The infrared light capturing capability of the lens enables effective target identification and monitoring even in low-light conditions or completely dark environments, such as night operations. In addition, the continuous zoom mechanism of the lens allows users to adjust the focal length, avoiding frequent lens replacement or non-continuous focal length switching, thereby ensuring the convenience of operation and the continuity of observation. These characteristics collectively endow the long-wave infrared continuous zoom optical lens with important value and practical advantages in various application scenarios. However, existing medium and long focal length lenses have at least one of the following shortcomings:

[0003] 1) In terms of materials, there are fewer optical materials on the market that can transmit long-wave infrared wavelengths, and these materials are expensive. It is difficult to achieve the best cost and imaging effect at the same time.

[0004] 2) Conventional visible light lenses cannot be used in harsh environments. For example, in fog, haze, and other harsh weather conditions, the clarity of the image will be greatly reduced, and even normal use will be affected.

[0005] 3) The structure of a typical zoom lens is complex and bulky, making it inconvenient to carry. At the same time, the zoom ratio of lenses on the market is relatively small for the same optical length.

[0006] 4) To meet different environmental needs, not only does it need to be stable within a certain range, but it also needs to take into account temperature changes. The MTF curve of existing similar systems on the market drops significantly at high temperatures (+60℃) and low temperatures (-40℃), and the image quality changes poorly.

[0007] 5) Compared to a single-focus lens, it is difficult to achieve clear imaging in different field-of-view ranges while maintaining the same image size. SUMMARY

[0008] Therefore, the purpose of the present application is to provide a large- zoom-ratio long-wave infrared continuous zoom optical lens and an electronic device. The lens can at least solve one of the technical shortcomings mentioned in the background.

[0009] According to one aspect of the present application, a large- zoom-ratio long-wave infrared continuous zoom optical lens is provided, which comprises, in order from the object side to the image side, a first fixed group, a zoom group, a compensation group, a second fixed group, and a focusing group.

[0010] When the lens changes from short focal length to long focal length, the first fixed group and the second fixed group remain unchanged, the variable group moves towards the image side, and the compensation group moves away from the image side, with a variable ratio of 9 times; at the short focal length end, the variable group and the compensation group are farthest apart and farthest from the target surface; at the long focal length end, the variable group and the compensation group are closest together and closest to the target surface;

[0011] The first fixed group includes a positive lens.

[0012] The variable group consists of two negative lenses.

[0013] The compensation group consists of a positive lens.

[0014] The second fixed group consists of a negative lens.

[0015] The focusing group consists of a positive lens.

[0016] In the above technical solution, the long-wave infrared continuous zoom system uses five-group variable zoom to achieve high-resolution and wide zoom ratio imaging performance. The first group is a fixed group that provides a stable optical reference; the second group is a variable group responsible for changing the magnification of the system; the third group is a compensation group used to correct optical distortion during zooming; the fourth group is a fixed group to maintain the optical stability of the system; and the fifth group is a focusing group used to fine-tune the focal length for optimal imaging results.

[0017] During the zooming process of the five-group variable zoom lens, when the lens focal length changes from short to long, the variable group moves towards the imaging plane, while the compensation group moves away from the imaging plane, and the relative position between the two changes to achieve continuous zooming of the optical system. At the short focal length position, the spacing between the variable group and the compensation group reaches a maximum, and at this time the distance between the variable group and the imaging plane also reaches a maximum value to ensure the imaging quality of the system. At the long focal length position, the spacing between the variable group and the compensation group is at a minimum, but still maintains a certain minimum center spacing to ensure the stability and imaging quality of the optical system, and at this time the distance between the variable group and the imaging plane reaches a minimum value. The combined focal length range of the system is 25 to 225 mm, the variable ratio is 9 times, and the field of view angle (DFOV) changes from 32.76° to 2.21°. The total length (TTL) of the system is <=253mm, and the relative aperture is between 1 / 1 and 1 / 1.25, ensuring high imaging quality and wide field of view angle. The imaging range is >=φ13.93mm, suitable for 640*512-17um or 640*512-12um sensors. The overall structure design is compact, small in size, easy to install and use, and has high practicality and operational convenience.

[0018] In some embodiments, the lens comprises, in order from the object side to the image side along an optical axis, a first lens, a second lens, a third lens, a fourth lens, a fifth lens, and a sixth lens;

[0019] The first lens has a positive refractive power, and an object-side surface is convex, and an image-side surface is concave;

[0020] The second lens has a negative refractive power, and an object-side surface is convex, and an image-side surface is concave;

[0021] The third lens has a negative refractive power, and an object-side surface is concave, and an image-side surface is convex;

[0022] The fourth lens has a positive refractive power, and an object-side surface is convex, and an image-side surface is convex;

[0023] The fifth lens has a negative refractive power, and an object-side surface is convex, and an image-side surface is concave;

[0024] The sixth lens has a positive refractive power, and an object-side surface is convex, and an image-side surface is concave.

[0025] In the above technical solution, in the optical zoom system, the second and third lenses are designed as negative lenses, which mainly undertake the function of system zoom. By precisely controlling the relative movement of the two lenses, the system can smoothly transition from short focal length to long focal length while maintaining image quality. The fourth lens is a positive lens, which mainly undertakes the function of compensating for image plane movement. During zooming, due to the movement of the second and third negative lenses, the position of the imaging plane changes, and the presence of the positive lens can effectively correct this change, ensuring the stability of the imaging quality. The fifth lens is a negative lens, and the sixth lens is a positive lens. This specific lens combination not only helps to achieve the zoom function of the system, but also has significant advantages in correcting residual aberrations. Through this combination, the system can effectively reduce optical distortion during zooming, improving the clarity and accuracy of the image. The system not only realizes high-ratio continuous zooming, but also ensures high imaging quality throughout the zoom range through effective aberration correction.

[0026] In some embodiments, the stop is disposed on the object side of the lens of the compensation group.

[0027] In the above technical solution, the stop is located on the object side of the lens of the compensation group; the movement of the stop is synchronized with the displacement of the lens of the compensation group to adapt to changes in optical requirements during zooming. This design not only helps to reduce the physical size of the optical system, but also effectively controls the aperture stop of the optical system, thereby optimizing the imaging quality and reducing the mirror aperture.

[0028] In some embodiments, the lens satisfies the following conditional expression:

[0029] Nd1>4, 150<|f1|<160

[0030] In the formula, f1 is the focal length of the first fixed group; and Nd1 is the refractive index of the first fixed group.

[0031] In the above technical solution, the focal length and refractive index of the first fixed group are set to correct high-order aberrations, thereby optimizing the imaging quality of the long focal length section. By controlling the focal length and refractive index, high-order aberrations in the optical system, such as spherical aberration, chromatic aberration, and astigmatism, are effectively corrected. The setting of the focal length ensures that the optical path length of the imaging system is reasonably controlled in the long focal length section, thereby reducing the imaging errors caused by the difference in optical path. At the same time, the optimization of the refractive index helps to adjust the refractive power of the lens to light, further reducing the influence of chromatic aberration and improving the clarity and contrast of the image.

[0032] In some embodiments, the lens satisfies the following conditional expression:

[0033] Nd2<4; Nd3>2.8

[0034] In the formula, Nd2 is the refractive index of the first lens on the object side of the variable magnification group; and Nd3 is the refractive index of the second lens on the object side of the variable magnification group.

[0035] In the above technical solution, the two negative lenses of the variable magnification group are designed with different refractive indices to balance the material cost and optical performance. The first lens uses a material with a lower refractive index (Nd2<4, refractive index ≈2.4), reducing the proportion of high-cost germanium material; and the second lens uses a material with a higher refractive index (Nd3>2.8, refractive index ≈3.1), enhancing the negative focal power to improve the variable magnification efficiency. The combination of the two ensures the divergence control ability of the variable magnification group to light while correcting residual aberrations through aspheric design, ensuring the stability of the image surface and the clarity of the edge field of view during zooming.

[0036] In some embodiments, both lenses of the variable magnification group are aspheric lenses.

[0037] In the above technical solution, aspheric lenses can effectively correct optical aberrations, which helps to minimize spherical aberration, coma, astigmatism, and distortion in the optical system. This can significantly improve the imaging quality, reduce the size and weight of the system.

[0038] In some embodiments, the lens satisfies the following conditional expression:

[0039] Nd4>4

[0040] In the formula, Nd4 is the refractive index of the lens of the compensation group, and the lens of the compensation group is an aspheric lens.

[0041] In the technical solution, the positive lens of the compensation group is made of high refractive index material (Nd4>4, such as germanium Ge, refractive index ≈4.0), so that it can provide sufficient optical power compensation for image surface deviation within a limited moving stroke, and the lens aperture is reduced to reduce the weight of the system. In combination with the aspheric surface type, the image surface deviation caused by temperature change during zooming can be effectively inhibited, the MTF curve stability in the range of-40℃ to +85℃ is ensured, and the problem of image quality degradation at high and low temperatures in the traditional lens is solved.

[0042] According to another aspect of the present application, there is provided an electronic device comprising a large- zoom-ratio long-wave infrared continuous zoom optical lens according to the above; and an image sensor configured to receive an image formed by the large-zoom-ratio long-wave infrared continuous zoom optical lens.

[0043] In the technical solution, the advantages of the electronic device depend on the large-zoom-ratio long-wave infrared continuous zoom optical lens, which will not be described here. BRIEF DESCRIPTION OF DRAWINGS

[0044] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the drawings needed in the embodiments or prior art description will be briefly introduced below. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can also be obtained by those skilled in the art without creative labor.

[0045] Figure 1 、 6 , 11 are structure schematic diagrams of example 1 to example 3 of a large-zoom-ratio long-wave infrared continuous zoom optical lens according to the present application, respectively;

[0046] Figure 2 、 7 , 12 are short-focus on-axis chromatic aberration diagrams of example 1 to example 3 of a large-zoom-ratio long-wave infrared continuous zoom optical lens according to the present application, respectively;

[0047] Figure 3 、 8 , 13 are long-focus on-axis chromatic aberration diagrams of example 1 to example 3 of a large-zoom-ratio long-wave infrared continuous zoom optical lens according to the present application, respectively;

[0048] Figure 4 、 9 , 14 are short-focus MTF diagrams of example 1 to example 3 of a large-zoom-ratio long-wave infrared continuous zoom optical lens according to the present application, respectively;

[0049] Figure 5 、 10 , 15 are long-focus MTF diagrams of example 1 to example 3 of a large-zoom-ratio long-wave infrared continuous zoom optical lens according to the present application, respectively;

[0050] Figure 16 Fig. 4 is a schematic configuration diagram of an electronic device according to Example 4 of the present application. DETAILED DESCRIPTION

[0051] The present application will be further described below in conjunction with the accompanying drawings and examples. It is particularly pointed out that the following examples are for illustration only and are not intended to limit the scope of the present application. Similarly, the following examples are only some of the embodiments of the present application, but not all the embodiments, and all other embodiments obtained by those of ordinary skill in the art without creative labor are within the scope of the present application.

[0052] The purpose of the present application is to propose a large- zoom-ratio long-wave infrared continuous zoom optical lens with high optical performance and an electronic device. Embodiments according to the present application will now be described in detail with reference to the accompanying drawings. Figure 1 、 Figure 6 、 Figure 11 are cross-sectional diagrams of large-zoom-ratio long-wave infrared continuous zoom optical lenses (optical systems) according to Examples 1 to 3, respectively. The large-zoom-ratio long-wave infrared continuous zoom optical lenses according to the respective examples are used in an imaging device including, for example, a digital video camera, a digital still camera, a broadcast camera, a surveillance camera, and the like, and an electronic device with a replaceable lens. In each cross-sectional diagram, the left side is the object side OBJ and the right side is the image side IMA. In each cross-sectional diagram, Li represents the i-th lens group, and Lij represents the j-th lens of the i-th lens group. ST represents a stop (a fixed stop or a variable stop), OA represents an optical axis, and G1 is a protective sheet. IMA represents an image plane, and a solid-state imaging element (photoelectric conversion element) such as a CMOS image sensor or a CCD image sensor is disposed on the imaging plane IMA when the large-zoom-ratio long-wave infrared continuous zoom optical lenses 1 to 3 according to the respective examples are used as an imaging optical system of a digital video camera or a digital still camera.

[0053] The large-zoom-ratio long-wave infrared continuous zoom optical lens according to each example includes, in order from the object side to the image side:

[0054] a first fixed group L1, a zoom group L2, a compensation group L3, a second fixed group L4, and a focus group L5;

[0055] When the lens is changed from a short focal length to a long focal length, the first fixed group L1 and the second fixed group L4 are fixed, the zoom group L2 moves toward the image side, and the compensation group L3 moves away from the image side, and the zoom ratio is 9 times. At the short focal length end, the zoom group L2 and the compensation group L3 are spaced apart the most and are farthest from the target plane IMA. At the long focal length end, the zoom group L2 and the compensation group L3 are spaced apart the least and are closest to the target plane IMA.

[0056] The first fixed group L1 includes a positive lens;

[0057] The zoom group L2 consists of two negative lenses;

[0058] The compensation group L3 consists of a single positive lens;

[0059] The second fixed group L4 consists of a negative lens;

[0060] The focusing group L5 consists of a single positive lens.

[0061] In this embodiment, the long-wave infrared continuous zoom system employs a five-element zoom to achieve high-resolution and wide zoom ratio imaging performance. The first element is a fixed element, providing a stable optical reference; the second element is a zoom element, responsible for changing the system's magnification; the third element is a compensation element, used to correct optical distortion during zooming; the fourth element is a fixed element, maintaining the system's optical stability; and the fifth element is a focusing element, used to fine-tune the focal length for optimal imaging. During zooming, as the lens focal length changes from short to long focal length, the zoom element moves closer to the imaging plane, while the compensation element moves further away, changing their relative positions to achieve continuous zooming of the optical system. At the short focal length, the interval between the zoom element and the compensation element reaches its maximum, and the distance between the zoom element and the imaging plane also reaches its maximum, ensuring the system's imaging quality. At the long focal length, the interval between the zoom element and the compensation element is minimum, but a certain minimum center distance is still maintained to ensure the stability of the optical system and imaging quality; at this point, the distance between the zoom element and the imaging plane reaches its minimum. The system features a combined focal length range of 25 to 225 mm, a zoom ratio of 9x, and a field of view (DFOV) varying from 32.76° to 2.21°. With a total length (TTL) of less than or equal to 253 mm and a relative aperture between 1 / 1 and 1 / 1.25, it ensures high image quality and a wide field of view. The imaging range is ≥ φ13.93 mm, suitable for 640*512-17 μm or 640*512-12 μm sensors. Its compact design and small size facilitate installation and use, offering high practicality and ease of operation.

[0062] In this embodiment, the lens includes a first lens L11, a second lens L21, a third lens L22, a fourth lens L31, a fifth lens L41, and a sixth lens L51 arranged sequentially along an optical axis from the object side to the image side.

[0063] The first lens L11 has positive refractive power, with a convex object-side surface and a concave image-side surface;

[0064] The second lens L21 has negative refractive power, with a convex object-side surface and a concave image-side surface;

[0065] The third lens L22 has negative refractive power, with a concave object side and a convex image side.

[0066] The fourth lens L31 has positive refractive power, and the object side is convex; the image side is also convex.

[0067] The fifth lens L41 has negative refractive power, with a convex object-side surface and a concave image-side surface;

[0068] The sixth lens L51 has positive refractive power, with a convex object side and a concave image side.

[0069] In this embodiment, the second and third lenses in this optical zoom system are designed as negative lenses, primarily responsible for the system's zoom function. By precisely controlling the relative movement of these two lenses, the system can achieve a smooth transition from short focal length to long focal length while maintaining image quality. The fourth lens is a positive lens, mainly responsible for compensating for image plane movement. During zooming, the position of the imaging plane changes due to the movement of the second and third negative lenses; the presence of the positive lens effectively corrects this change, ensuring the stability of image quality. The fifth lens is a negative lens, while the sixth lens is a positive lens. This specific lens combination not only helps to achieve the system's zoom function but also has significant advantages in correcting residual aberrations. Through this combination, the system can effectively reduce optical distortion during zooming, improving image sharpness and accuracy. This system not only achieves high-magnification continuous zoom but also ensures high image quality throughout the entire zoom range through effective aberration correction.

[0070] In this embodiment, the aperture stop ST is disposed on the object-side surface of the lens of the compensation group L3, specifically on the object-side surface of the fourth lens L31. The aperture stop is located on the object-side surface of the lens of the compensation group; the movement of the aperture stop is synchronized with the displacement of the lens of the compensation group to adapt to changes in optical requirements during zooming. This design not only helps to reduce the physical size of the optical system, but also effectively controls the aperture stop of the optical system, thereby optimizing image quality and reducing the mirror aperture.

[0071] In this embodiment, both lenses in the zoom group are aspherical lenses. Aspherical lenses can effectively correct optical aberrations, helping to minimize aberrations such as spherical aberration, coma, astigmatism, and distortion in the optical system. This can significantly improve image quality and reduce system size and weight.

[0072] In this embodiment, the lens of compensation group L3 is an aspherical lens. Specifically, the fourth lens L31 is an aspherical lens. This balances chromatic aberration correction with system compactness.

[0073] According to the examples of high zoom ratio long-wave infrared continuous zoom optical lenses, at least one of the following setting conditions 1) to 3) can be satisfied:

[0074] 1) Nd1>4, 150<|f1|<160;

[0075] 2) Nd2>4; Nd3>2.8;

[0076] 3) Nd4 > 4;

[0077] In the above conditional expressions, f1 is the focal length of the first fixed group; Nd1 is the refractive index of the first fixed group; Nd2 is the refractive index of the first lens on the object side of the zoom group; Nd3 is the refractive index of the second lens on the object side of the zoom group; and Nd4 is the refractive index of the lens in the compensation group.

[0078] Condition 1) defines the focal length and refractive index of the first fixed group, specifically the focal length and refractive index of the first lens. By appropriately setting these conditions, higher-order aberrations can be corrected, thereby optimizing the imaging quality in the long focal length range. By controlling the focal length and refractive index, higher-order aberrations in the optical system, such as spherical aberration, chromatic aberration, and astigmatism, are effectively corrected. The focal length setting ensures that the optical path length of the imaging system is reasonably controlled in the long focal length range, thereby reducing imaging errors caused by differences in the optical path. At the same time, optimizing the refractive index helps adjust the lens's ability to refract light, further reducing the influence of chromatic aberration and improving image sharpness and contrast. In the above settings: if the refractive index Nd1 of the first fixed group is lower than the lower limit, the lens material has insufficient dispersion capability, making chromatic aberration correction difficult at the telephoto end, and the axial dispersion will exceed 1.5 pixel size at a focal length of 225mm; if the focal length |f1| is higher than the upper limit, the first group of optical focal length is too weak and cannot effectively compress the movement space of the subsequent zoom group, causing the total system length to exceed the design constraint of 253mm; if the focal length |f1| is lower than the lower limit, the field curvature distortion at the short focal length end will increase; in addition, in order to reliably obtain the effect of condition 1), it is more preferable to set the value of condition 1) to limit Nd1 to 4.0-4.2 (germanium material), which can balance chromatic aberration correction and system compactness.

[0079] Condition 2) defines the refractive index Nd2>4 of the first lens on the object side of the zoom group; and the refractive index Nd3>2.8 of the second lens on the object side of the zoom group. Specifically, if Nd2≤4 (e.g., Nd=2.4 when using ZnSe), the negative optical power is insufficient, resulting in a zoom ratio that cannot reach 9x, and the focal length at the telephoto end will be limited to below 180mm. If Nd3≤2.8 (e.g., Nd=2.2 when using ZnS), the optical power matching between the two lenses in the zoom group is unbalanced, and the image plane drift exceeds ±0.1mm during movement, requiring an additional compensation group travel. Therefore, Nd2=4.0-4.3(Ge) and Nd3=2.8-3.2 are selected. Combined with the aspherical coefficients K1=-0.8 to -1.2 of the two negative lenses, the nonlinear error of the zoom trajectory can be suppressed to within ±5μm.

[0080] Condition 3) If Nd4 ≤ 4 (e.g., if Si is used, Nd = 3.4), then the positive optical power needs to be compensated by increasing the curvature, resulting in a lens edge thickness of less than 0.5 mm and a processing yield dropping below 60%; at the same time, the coefficient of thermal expansion of low refractive index materials (e.g., Si's CTE = 2.6 × 10⁻⁶) will be affected. -6 / ℃) and lens barrel material (aluminum alloy CTE=23×10 -6 / ℃) mismatch, resulting in 0.05mm defocus at -40℃ and a 30% drop in MTF; therefore, choosing Nd4 = 4.0-4.5 (Ge), with an aspherical term number ≥ 6, can correct coma during zooming to below λ / 4, and utilize the negative thermal expansion characteristic of Ge (dn / dT≈-400×10) -6 / ℃) to offset lens barrel deformation, ensuring MTF fluctuations at high and low temperatures are ≤10%.

[0081] A detailed description of high zoom ratio long-wave infrared continuous zoom optical lenses based on various examples is now provided.

[0082] Example 1

[0083] Please refer to the optical structure of Example 1. Figure 1 The specific parameters of Example 1 are shown in Tables 1, 2, and 3 below. In Example 1, the combined focal length of the lens is 25–225 mm, the zoom ratio is 9x, the DFOV is 32.76°–2.21°, the TTL is <= 253 mm, the relative aperture is 1 / 1–1 / 1.25, the imaging quality is high, the imaging range is ≥ φ13.93 mm, it is suitable for 640*512-17 μm or 640*512-12 μm sensors, the overall structure is compact, the size is small, the practicality is strong, and the installation and use are extremely convenient.

[0084] Conditions 1) to 3) are as follows:

[0085] 1) Nd1=4.0032, |f1|=155.8545;

[0086] 2)Nd2=4.0032; Nd3=2.7781;

[0087] 3) Nd4 = 4.0032;

[0088] Table 1 Example 1 Parameter Table

[0089] Surface No. Surface Radius of curvature Interval Material Refractive index Focal length 0 OBJ Infinity Infinity 1 First lens 165.7951 16.20 Glass 4.0032 155.8545 2 237.9156 48.55 3 Second lens 151.7661 3.50 Glass 4.0032 -42.3372 4 67.9880 9.25 5 Third lens -118.5856 3.45 Glass 2.7781 -101.655 6 -351.2216 87.31 7 Infinity 0.00 8 Fourth lens / stop 459.9393 8.25 Glass 4.0032 47.52285 9 -204.1469 1.12 10 Fifth lens 75.86671 11.39 Glass 2.7781 -184.549 11 55.6990 34.01 12 Infinity 5.43 13 Sixth lens 44.4262 5.68 Glass 4.0032 45.75126 14 59.3574 2.00 15 Infinity 13.10 16 Protective sheet Infinity 1.00 Glass 4.0032 Infinity 17 Infinity 1.48 18 Infinity 1.34 19 Image surface Infinity

[0090] Table 2 Example 1 Aspherical Surface Parameter Table

[0091] Surface No. S3 S4 S5 S6 S8 conic 0 0 0 0 0 A4 7.36E-07 1.6E-06 -1.5E-07 -9.6E-07 -6E-07 A6 -7.4E-09 -9.8E-09 -7.9E-09 -5.9E-09 8.8E-10 A8 6.75E-12 7.82E-12 1.23E-11 1.05E-11 -3.5E-13 A10 -1.9E-15 -1.7E-15 -5.1E-15 -4.5E-15 7.59E-17 A12 0 0 0 0 0 A14 0 0 0 0 0 A16 0 0 0 0 0 Surface No. S9 S10 S11 S13 S14 conic 0 0 0 0 0 A4 -4.9E-07 -3.9E-06 -7E-06 1.11E-06 2.14E-06 A6 8.31E-10 -3.7E-09 -8.5E-09 -2.5E-08 -4.6E-08 A8 -3.2E-13 1.02E-12 1.26E-11 2.66E-12 2.31E-11 A10 7.14E-17 4.68E-16 -6E-15 -4.1E-14 -2.9E-15 A12 0 0 0 0 0 A14 0 0 0 0 0 A16 0 0 0 0 0

[0092] Table 3 Example 1: Variation parameters of zoom lenses

[0093] Short focal length end Long focal length end d1 48.4011 mm 1.4232 mm [d2] 87.5264 mm 93.7611 mm Field of view DFOV 32.76° 2.21° Focal length 25 mm 225 mm Aperture 1.0 1.28 Image surface size φ 13.93 mm φ 13.93 mm Total optical length 253 mm 253 mm

[0094] Please see Figure 2 Example 1 shows the chromatic aberration diagram on the short focal length axis of the lens, which achieves consistency in multispectral imaging at the short focal length.

[0095] Please see Figure 3 Example 1 shows the chromatic aberration diagram on the telephoto axis of the lens, which achieves consistency in multispectral imaging at the telephoto end.

[0096] Please see Figure 4 Example 1 shows the MTF chart of a short focal length lens, which achieved clear imaging at 25mm.

[0097] Please see Figure 5 Example 1 shows the MTF chart of the telephoto lens, which achieved clear imaging at 225mm.

[0098] Example 2

[0099] Please refer to the optical structure of Example 2. Figure 6 The specific parameters of Example 2 are shown in Tables 4, 5, and 6 below. In Example 2, the combined focal length of the lens is 25–225 mm, the magnification ratio is 9x, the DFOV is 32.76°–2.21°, the TTL is <= 253 mm, the relative aperture is 1 / 1 to 1 / 1.25, the image quality is high, and the imaging range is ≥ φ.

[0100] With a diameter of 13.93mm, it is suitable for 640*512-17um or 640*512-12um sensors. It has a compact overall structure, small size, strong practicality, and is extremely convenient to install and use.

[0101] Conditions 1) to 3) are as follows:

[0102] 4) Nd1=4.0032, |f1|=156.1013;

[0103] 5)Nd2=4.0032; Nd3=2.7781;

[0104] 6) Nd4 = 4.0032;

[0105] Table 4 Example 2 Parameter Table

[0106] Surface No. Surface Radius of curvature Interval Material Refractive index Focal length 0 OBJ Infinity Infinity 1 First lens 165.7801 16.20 Glass 4.0032 156.1013 2 237.6730 48.52 3 Second lens 142.8538 3.50 Glass 4.0032 -41.2663 4 65.1408 9.41 5 Third lens -122.5170 3.45 Glass 2.7781 -107.258 6 -348.8030 87.14 7 Infinity 0 8 Fourth lens / stop 457.0803 8.29 Glass 4.0032 47.26195 9 -203.0620 1.17 10 Fifth lens 76.8963 12.20 Glass 2.7781 -176.627 11 55.4956 32.61 12 Infinity 6.09 13 Sixth lens 44.5036 5.64 Glass 4.0032 45.90952 14 59.4712 3.00 15 Infinity 12.10 16 Protective sheet Infinity 1.00 Glass 4.0032 Infinity 17 Infinity 1.62 18 Infinity 1.10 19 Image surface Infinity

[0107] Table 5 Example 2 Aspherical Surface Parameter Table

[0108]

[0109]

[0110] Table 6 Example 2: Variation Parameters of Zoom Lenses

[0111] Short focal length end Long focal length end d1 47.6451 mm 93.7611 mm [d2] 88.4825 mm 1.4869 mm Field of view DFOV 32.75° 2.22° Focal length 25 mm 225 mm Aperture 1.0 1.27 Image surface size φ 13.93 mm φ 13.93 mm Total optical length 253 mm 253 mm

[0112] Please see Figure 7 Example 2 shows the chromatic aberration diagram on the short focal length axis of the lens, which achieves consistency in multispectral imaging at the short focal length.

[0113] Please see Figure 8 Example 2: Chromatic aberration diagram on the telephoto axis of the lens. The telephoto section achieves consistency in multispectral imaging.

[0114] Please see Figure 9 Example 2 shows the MTF chart of a short focal length lens, demonstrating that clear imaging was achieved at 25mm.

[0115] Please see Figure 10 Example 2 shows the MTF chart of the telephoto lens, which achieved clear imaging at 225mm.

[0116] Example 3

[0117] Please refer to the optical structure of Example 3. Figure 11 The specific parameters of Example 3 are shown in Tables 7, 8, and 9 below. In Example 3, the combined focal length of the lens is 25–225 mm, the magnification ratio is 9x, the DFOV is 32.76°–2.21°, the TTL is <= 253 mm, the relative aperture is 1 / 1 to 1 / 1.25, the image quality is high, and the imaging range is ≥ φ.

[0118] With a diameter of 13.93mm, it is suitable for 640*512-17um or 640*512-12um sensors. It has a compact overall structure, small size, strong practicality, and is extremely convenient to install and use.

[0119] Conditions 1) to 3) are as follows:

[0120] 7) Nd1=4.0032, |f1|=152.5658;

[0121] 8) Nd2=4.0032; Nd3=2.7781;

[0122] 9) Nd4 = 4.0032;

[0123] Table 7 Example 3 Parameter Table

[0124]

[0125]

[0126] Table 8 Example 3 Aspherical Surface Parameter Table

[0127] Surface No. S3 S4 S5 S6 S8 conic 0 0 0 0 0 A4 -1.9E-06 -1.9E-06 -3.4E-06 -3.2E-06 -9.2E-07 A6 -7.1E-10 -1.1E-09 1.06E-09 1.3E-09 1.68E-09 A8 6.69E-13 1.48E-13 2.33E-12 1.8E-12 -1.3E-12 A10 -4.7E-18 3.98E-16 -1.2E-15 -8.8E-16 4.47E-16 A12 0 0 0 0 0 A14 0 0 0 0 0 A16 0 0 0 0 0 Surface No. S9 S10 S11 S13 S14 conic 0 0 0 0 0 A4 -8.1E-07 -3.9E-06 -6.7E-06 2.32E-06 4.04E-06 A6 1.6E-09 -4.8E-09 -1.1E-08 -2.7E-08 -5.2E-08 A8 -1.2E-12 8.06E-13 1.52E-11 8.06E-12 4.06E-11 A10 4.19E-16 1.19E-15 -6.9E-15 -3.2E-14 -1.2E-14 A12 0 0 0 0 0 A14 0 0 0 0 0 A16 0 0 0 0 0

[0128] Table 9 Example 3: Variation parameters of zoom lenses

[0129]

[0130]

[0131] Please see Figure 12 Example 3 shows the chromatic aberration diagram on the short focal length axis of the lens, which achieves consistency in multispectral imaging at the short focal length.

[0132] Please see Figure 13 Example 3 demonstrates that the chromatic aberration map on the telephoto axis of the lens achieves consistency in multispectral imaging at the telephoto end.

[0133] Please see Figure 14 Example 3 shows the MTF chart of a short focal length lens, demonstrating that clear imaging was achieved at 25mm.

[0134] Please see Figure 15 Example 3 shows the MTF chart of the telephoto lens, which achieved clear imaging at 225mm.

[0135] Based on Examples 1 to 3, this case has the following advantages:

[0136] 1. In terms of materials, the present invention uses germanium-based materials for the first, second, fourth, and sixth lenses, and chalcogenide-based materials for the third and fifth lenses, effectively correcting the aberrations of the optical system when the magnification ratio is 9x.

[0137] 2. Among existing lenses of the same optical length, the zoom ratio of lenses on the market is relatively small, while this zoom system achieves 9x zoom;

[0138] 3. It adopts a mechanical active compensation calorimetric design, which can output high-definition images in high and low temperature environments (-40℃ to 60℃).

[0139] 4. The lens can be used with both 640*512@12um and 640*512@17um uncooled detectors, providing high resolution across the entire target area and consistent imaging quality from the center to the edge.

[0140] 5. By rationally allocating optical power and using aspherical lenses, the number of lenses can be reduced, thereby lowering production costs.

[0141] 6. Select a suitable zoom structure to achieve a continuous zoom optical system design of 25-225mm, ensuring clear imaging at different focal lengths.

[0142] 7. With the same optical specifications, the total length of this system is 253mm, which effectively shortens the length of the optical system and reduces the weight of the system, making it easy to carry and install in various situations.

[0143] Example 4

[0144] For reference Figure 16 A description of an electronic device A according to Example 5 of the present invention will be given. Figure 16 This is a schematic diagram of an electronic device (industrial camera) used in a camera optical system, based on any of the high zoom ratio long-wave infrared continuous zoom optical lenses according to Examples 1 to 3. Figure 16 In the figures, reference numeral A2 indicates the main body of the electronic device, and reference numeral A1 indicates any of the camera optical systems (interchangeable lenses) including the large zoom ratio long-wave infrared continuous zoom optical lenses according to Examples 1 to 3. Reference numeral A3 indicates an image sensor (photoelectric conversion element) such as a CMOS image sensor or a CCD image sensor, which is built into the camera body A2 and receives light (the optical image formed by the camera optical system A1) from the camera optical system A1 and performs photoelectric conversion.

[0145] By using a high zoom ratio long-wave infrared continuous zoom optical lens according to any one of Examples 1 to 3 in an electronic device such as a digital still camera, an electronic device with a high zoom ratio long-wave infrared continuous zoom optical lens can be obtained. The various examples can provide an electronic device with high optical performance.

[0146] Although the invention has been described with reference to exemplary embodiments, it should be understood that the invention is not limited to the disclosed exemplary embodiments. The scope of the following claims will be given the broadest interpretation to cover all such modifications and equivalent structures and functions.

Claims

1. A large zoom ratio long wave infrared continuous zoom optical lens characterized by, The first fixed group, the zooming group, the compensation group, the second fixed group and the focusing group are arranged in order from the object side to the image side. When the lens changes from short focal length to long focal length, the first fixed group and the second fixed group remain unchanged, the zooming group moves towards the image side, and the compensation group moves away from the image side, and the zooming ratio is 9 times; at the short focal length end, the zooming group and the compensation group are farthest apart and farthest from the target surface; at the long focal length end, the zooming group and the compensation group are closest together and closest to the target surface. The first fixed group includes a positive lens. The zooming group includes two negative lenses. The compensation group includes a positive lens. The second fixed group includes a negative lens. The focusing group includes a positive lens.

2. The long-wave infrared continuous zoom optical lens of claim 1, wherein the lens comprises, in order from an object side to an image side along an optical axis, a first lens, a second lens, a third lens, a fourth lens, a fifth lens, and a sixth lens. The first lens has a positive refractive power, and an object side surface is convex and an image side surface is concave. The second lens has a negative refractive power, and an object side surface is convex and an image side surface is concave. The third lens has a negative refractive power, and an object side surface is concave and an image side surface is convex. The fourth lens has a positive refractive power, and an object side surface is convex and an image side surface is convex. The fifth lens has a negative refractive power, and an object side surface is convex and an image side surface is concave. The sixth lens has a positive refractive power, and an object side surface is convex and an image side surface is concave.

3. The long-wave infrared continuous zoom optical lens of claim 1, wherein the stop is disposed on an object side surface of a lens of the compensation group.

4. The long-wave infrared continuous zoom optical lens of claim 1, wherein the lens satisfies the following condition formula: Nd1>4, 150<|f1|<160 wherein f1 is a focal length of the first fixed group, and Nd1 is a refractive index of the first fixed group.

5. The long-wave infrared continuous zoom optical lens of claim 1, wherein the lens satisfies the following condition formula: Nd2<4; Nd3>2.8 wherein Nd2 is a refractive index of a first lens of the zooming group, and Nd3 is a refractive index of a second lens of the zooming group.

6. The long-wave infrared continuous zoom optical lens of claim 1, wherein both lenses of the zooming group are aspherical lenses.

7. The long-wave infrared continuous zoom optical lens of claim 1, wherein the lens satisfies the following condition formula: Nd4>4 wherein Nd4 is a refractive index of a lens of the compensation group. The long-wave infrared continuous zoom optical lens of any one of claims 1-7; and an image sensor configured to receive an image formed by the long-wave infrared continuous zoom optical lens.

8. A long-wave infrared continuous zoom optical lens, comprising: a first fixed group; a zooming group; a compensation group; a second fixed group; and a focusing group, wherein the first fixed group, the zooming group, the compensation group, the second fixed group and the focusing group are arranged in order from an object side to an image side along an optical axis, and wherein the first fixed group includes a positive lens, the zooming group includes two negative lenses, the compensation group includes a positive lens, the second fixed group includes a negative lens, and the focusing group includes a positive lens. ​ ​ ​ 8. An electronic device, comprising: ​ ​

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