Athermal continuous zoom optical system

Abstract

The present invention belongs to the technical field of imaging optical systems, and relates to an athermal continuous zoom optical system, which is composed of a front fixed lens group with positive focal length, a variable lens group with negative focal length, a compensating lens group with positive focal length, a rear fixed lens group with negative focal length, and a target surface, which are arranged in sequence along the optical axis from the object side to the image side; when zooming, the front fixed lens group and the rear fixed lens group are fixed, and the variable lens group and the compensating lens group move in opposite directions to achieve the system's magnification change and compensate for the deviation of the image surface. The present invention has a wide working band range, and can achieve parfocal imaging from visible light to near-infrared without the need to add additional filters or move the target surface, and can achieve clear imaging without focusing when the ambient temperature changes within the range of ‑40°C to 60°C, quickly realizes the recognition and tracking of typical targets at different distances, avoids adverse effects such as target loss caused by repeated focusing, and is conducive to the needs of miniaturization and lightweight optoelectronic tracking systems.

Description

Technical Field

[0001] The present invention belongs to the technical field of imaging optical systems, and in particular relates to an athermal continuous zoom optical system. Background Art

[0002] Photoelectric tracking systems generally use multi-channel spectral detection technology to achieve all-weather identification and tracking of targets. The visible light imaging tracker in the photoelectric tracking system usually uses a continuous zoom optical system to achieve identification and tracking of typical targets at different distances. With the increasing demand for target identification in foggy, rainy weather or low-light conditions, it is necessary for the design band of the visible light continuous zoom optical system to cover both the visible light band and the near-infrared band to adapt to various working environments. In actual use, with the changes in altitude, climate, region and season, the operating temperature will vary over a large range, and the resulting thermal defocus will also have a great impact on the imaging quality of the optical system. Summary of the invention

[0003] The technical problem to be solved by the present invention is to provide an athermal continuous zoom optical system which can simultaneously cover the visible light and near infrared bands of 450 to 900 nm to meet the requirements of working through fog or in low illumination conditions.

[0004] In order to solve the above technical problems, the athermal continuous zoom optical system of the present invention is composed of a front fixed lens group with positive optical power, a variator lens group with negative optical power, a compensator lens group with positive optical power, a rear fixed lens group with negative optical power and a target surface, which are arranged in sequence along the optical axis from the object side to the image side; the focal length f1 of the front fixed lens group, the focal length f2 of the variator lens group, the focal length f3 of the compensator lens group, the focal length f4 of the rear fixed lens group and the shortest focal length fs satisfy the relationship:

[0005] 8.81<f1 / fs<9.03; -1.93<f2 / fs<-1.86; 2.00<f3 / fs<2.10; -20.00<f4 / fs<-7.20;

[0006] When the focal length changes from the shortest focal length to the longest focal length, the front fixed lens group and the rear fixed lens group are fixed, and the magnification lens group moves along the optical axis from the object side to the image side to achieve the system's magnification change, and at the same time the compensation lens group moves along the optical axis from the image side to the object side to compensate for the offset of the image plane; when the focal length changes from the longest focal length to the shortest focal length, the front fixed lens group and the rear fixed lens group are fixed, and the magnification lens group moves along the optical axis from the image side to the object side to achieve the system's magnification change, and at the same time the compensation lens group moves along the optical axis from the object side to the image side to compensate for the offset of the image plane.

[0007] Furthermore, the total length TL1 of the front fixed lens group on the optical axis, the total length TL2 of the zoom lens group on the optical axis, the total length TL3 of the compensation lens group on the optical axis, the total length TL4 of the rear fixed lens group on the optical axis and the total length TTL of the optical system satisfy the following relationship:

[0008] 0.11<TL1 / TTL<0.15; 0.077<TL2 / TTL<0.080; 0.043<TL3 / TTL<0.055; 0.095<TL4 / TTL<0.118.

[0009] The front fixed lens group consists of a first lens, a second lens and a third lens arranged in sequence from the object side to the image side; the zoom lens group consists of a fourth lens, a fifth lens and a sixth lens arranged in sequence from the object side to the image side; the compensation lens group consists of a seventh lens, an eighth lens, a ninth lens and a tenth lens arranged in sequence from the object side to the image side; the rear fixed lens group consists of an eleventh lens, a twelfth lens, a thirteenth lens and a fourteenth lens arranged in sequence from the object side to the image side; the thickness of the first lens is 3.80mm~4.50mm, the thickness of the second lens is 1.05mm~1.40mm, the thickness of the third lens is 9.01mm~12.76mm, and the thickness of the fourth lens is 1.00mm ~1.05mm, the thickness of the fifth lens is 5.00mm~5.22mm, the thickness of the sixth lens is 1.20mm~1.50mm, the thickness of the seventh lens is 1.48mm~1.81mm, the thickness of the eighth lens is 1.00mm~1.04mm, the thickness of the ninth lens is 2.12mm~2.18mm, the thickness of the tenth lens is 1.02mm~1.27mm, the thickness of the eleventh lens is 1.18mm~1.66mm, the thickness of the twelfth lens is 1.00mm~1.13mm, the thickness of the thirteenth lens is 0.88mm~1.06mm, and the thickness of the fourteenth lens is 2.66mm~2.90mm.

[0010] The air gap between the first lens and the second lens is 0.13mm~0.46mm, the air gap between the second lens and the third lens is 1.26mm~1.80mm, the air gap between the third lens and the fourth lens is 1.50mm~48.98mm, the air gap between the fourth lens and the fifth lens is 0, the air gap between the fifth lens and the sixth lens is 3.38mm~3.60mm, the air gap between the sixth lens and the seventh lens is 0.97mm~65.87mm, and the air gap between the seventh lens and the eighth lens is 0.11m m~0.46mm, the air gap between the eighth lens and the ninth lens is 0.28mm~1.16mm, the air gap between the ninth lens and the tenth lens is 0~0.15mm, the air gap between the tenth lens and the eleventh lens is 1.09mm~22.02mm, the air gap between the eleventh lens and the twelfth lens is 5.33mm~7.63mm, the air gap between the twelfth lens and the thirteenth lens is 1.10mm~1.39mm, and the air gap between the thirteenth lens and the fourteenth lens is 0.14mm~0.23mm.

[0011] The air distance between the third lens and the fourth lens is 47.03mm~48.98mm at long focus, 38.98mm~40.75mm at medium focus, and 1.50mm~2.59mm at short focus; the air distance between the sixth lens and the seventh lens is 0.97mm~1.05mm at long focus, 15.69mm~16.36mm at medium focus, and 63.44mm~65.87mm at short focus; the air distance between the tenth lens and the eleventh lens is 17.71mm~22.02mm at long focus, 11.06mm~14.74mm at medium focus, and 1.09mm~2.92mm at short focus.

[0012] The first lens, the second lens, the third lens, the fourth lens, the fifth lens, the sixth lens, the seventh lens, the eighth lens, the ninth lens, the tenth lens, the eleventh lens, the twelfth lens, the thirteenth lens and the fourteenth lens are all glass spherical lenses, and their refractive indices n1, n2, ..., n14 and Abbe numbers v1, v2, ..., v14 respectively satisfy the following relationship:

[0013] 1.48<n1<1.56, 1.60<n2<1.63, 1.59<n3<1.60, 1.64<n4 <1.67, 1.80<n5<1.85, 1.61<n6<1.63, 1.43<n7<1.46, 1. 85<n8<1.96, 1.49<n9<1.60, 1.74<n10<1.78, 1.61<n11< 1.65, 1.51<n12<1.53, 1.85<n13<1.86, 1.61<n14<1.63;

[0014] 59.50<v1<70.60, 35.50<v2<38.30, 67.00<v3<69.00, 54.50<v4 <60.50, 23.50<v5<25.60, 55.50<v6<56.80, 90.10<v7<95.00, 31 .20<v8<32.50, 68.20<v9<82.00, 49.20<v10<49.65, 33.50<v11< 37.20, 58.50<v12<64.50, 30.00<v13<32.50, 35.50<v14<36.80.

[0015] The first lens is a biconvex lens; the second lens is a meniscus lens with negative focal power, and its convex surface faces the object; the third lens is a meniscus lens with positive focal power, and its convex surface faces the object; the fourth lens and the fifth lens form a first cemented lens group, the fourth lens is a biconcave lens, the fifth lens is a meniscus lens with positive focal power, and its convex surface faces the object; the sixth lens is a biconcave lens; the seventh lens is a biconvex lens; the eighth lens is a meniscus lens with negative focal power, and its convex surface faces the object; the ninth lens is a biconvex lens; the tenth lens is a meniscus lens with negative focal power, and its convex surface faces the image; the ninth lens and the tenth lens form a second cemented lens group; the eleventh lens is a meniscus lens with negative focal power, and its convex surface faces the image; the twelfth lens is a meniscus lens with negative focal power, and its convex surface faces the object; the thirteenth lens is a biconcave lens; and the fourteenth lens is a biconvex lens.

[0016] The first lens is a biconvex lens; the second lens is a meniscus lens with negative focal power, and the convex surface faces the object; the third lens is a biconvex lens; the fourth lens and the fifth lens form a first cemented lens group, the fourth lens is a biconcave lens, the fifth lens is a meniscus lens with positive focal power, and the convex surface faces the object; the sixth lens is a biconcave lens; the seventh lens is a biconvex lens; the eighth lens is a meniscus lens with negative focal power, and the convex surface faces the object; the ninth lens is a biconvex lens; the tenth lens is a meniscus lens with negative focal power, and the convex surface faces the image; the ninth lens and the tenth lens form a second cemented lens group; the eleventh lens is a meniscus lens with negative focal power, and the convex surface faces the image; the twelfth lens is a meniscus lens with negative focal power, and the convex surface faces the object; the thirteenth lens is a biconcave lens; and the fourteenth lens is a biconvex lens.

[0017] The first lens is a biconvex lens; the second lens is a meniscus lens with negative focal power, and its convex surface faces the object; the third lens is a biconvex lens; the fourth lens and the fifth lens form a first cemented lens group, the fourth lens is a biconcave lens, the fifth lens is a meniscus lens with positive focal power, and its convex surface faces the object; the sixth lens is a biconcave lens; the seventh lens is a biconvex lens; the eighth lens is a meniscus lens with negative focal power, and its convex surface faces the object; the ninth lens is a meniscus lens with positive focal power, and its convex surface faces the object; the tenth lens is a meniscus lens with positive focal power, and its convex surface faces the object; the ninth lens and the tenth lens form a second cemented lens group; the eleventh lens is a meniscus lens with positive focal power, and its convex surface faces the image; the twelfth lens is a meniscus lens with negative focal power, and its convex surface faces the object; the thirteenth lens is a biconcave lens; and the fourteenth lens is a biconvex lens.

[0018] The first lens is a biconvex lens; the second lens is a meniscus lens with negative focal power, and its convex surface faces the object; the third lens is a biconvex lens; the fourth lens and the fifth lens form a first cemented lens group, the fourth lens is a biconcave lens, the fifth lens is a meniscus lens with positive focal power, and its convex surface faces the object; the sixth lens is a biconcave lens; the seventh lens is a biconvex lens; the eighth lens is a meniscus lens with negative focal power, and its convex surface faces the object; the ninth lens and the tenth lens are single lenses respectively; the ninth lens is a meniscus lens with positive focal power, and its convex surface faces the object; the tenth lens is a meniscus lens with positive focal power, and its convex surface faces the object; the eleventh lens is a meniscus lens with negative focal power, and its convex surface faces the image; the twelfth lens is a meniscus lens with negative focal power, and its convex surface faces the object; the thirteenth lens is a meniscus lens with negative focal power, and its convex surface faces the object; and the fourteenth lens is a biconvex lens.

[0019] The beneficial effects of the present invention are as follows: the athermal continuous zoom optical system has a wide operating band range, and can achieve parfocal imaging from visible light to near-infrared without the need to add additional filters or move the target surface. In addition, appropriate filters can be flexibly introduced according to scene requirements to achieve separate imaging in the visible light or near-infrared bands. It can be flexibly adapted to 2 / 3", 1 / 2", and 1 / 1.7" detectors currently on the market, and can achieve clear imaging without focusing when the ambient temperature changes within the range of -40°C to 60°C. It quickly realizes the recognition and tracking of typical targets at different distances, avoids adverse effects such as target loss caused by repeated focusing, and is beneficial to the miniaturization and lightweight requirements of the optoelectronic tracking system. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 to Figure 3 They are respectively optical structure diagrams of the long focus, medium focus and short focus of Example 1 of the athermal continuous zoom optical system of the present invention.

[0021] Figures 4 to 6They are respectively the modulation transfer function curves of the long focus, medium focus and short focus of Example 1 of the athermal continuous zoom optical system of the present invention when the working temperature is 20°C.

[0022] Figure 7 to Figure 9 They are respectively the modulation transfer function curves of the long focus, medium focus and short focus of Example 1 of the athermal continuous zoom optical system of the present invention when the working temperature is -40°C.

[0023] Figure 10 to Figure 12 They are respectively the modulation transfer function curves of the long focus, medium focus and short focus of Example 1 of the athermal continuous zoom optical system of the present invention when the working temperature is 60°C.

[0024] Figure 13 to Figure 15 They are respectively the optical structure diagrams of the long focus, medium focus and short focus of Example 2 of the athermal continuous zoom optical system of the present invention.

[0025] Figure 16 to Figure 18 They are respectively the modulation transfer function curves of the long focus, medium focus and short focus of Embodiment 2 of the athermal continuous zoom optical system of the present invention when the working temperature is 20°C.

[0026] Figure 19 to Figure 21 They are respectively the modulation transfer function curves of long focus, medium focus and short focus of embodiment 2 of the athermal continuous zoom optical system of the present invention when the working temperature is -40°C.

[0027] Figure 22 to Figure 24 They are respectively the modulation transfer function curves of the long focus, medium focus and short focus of Embodiment 2 of the athermal continuous zoom optical system of the present invention when the working temperature is 60°C.

[0028] Figure 25 to Figure 27 They are respectively optical structure diagrams of the long focus, medium focus and short focus of Example 3 of the athermal continuous zoom optical system of the present invention.

[0029] Figure 28 to Figure 30 They are respectively the modulation transfer function curves of the long focus, medium focus and short focus of Example 3 of the athermal continuous zoom optical system of the present invention when the working temperature is 20°C.

[0030] Figure 31 to Figure 33 They are respectively the modulation transfer function curves of long focus, medium focus and short focus of Example 3 of the athermal continuous zoom optical system of the present invention when the working temperature is -40°C.

[0031] Figure 34 to Figure 36 They are respectively the modulation transfer function curves of the long focus, medium focus and short focus of Example 3 of the athermal continuous zoom optical system of the present invention when the working temperature is 60°C.

[0032] Figure 37 to Figure 39 They are respectively optical structure diagrams of the long focus, medium focus and short focus of Example 4 of the athermal continuous zoom optical system of the present invention.

[0033] Figure 40 to Figure 42 They are respectively the modulation transfer function curves of the long focus, medium focus and short focus of Example 4 of the athermal continuous zoom optical system of the present invention when the working temperature is 20°C.

[0034] Figure 43 to Figure 45 They are respectively the modulation transfer function curves of the long focus, medium focus and short focus of Example 4 of the athermal continuous zoom optical system of the present invention when the working temperature is -40°C.

[0035] Figure 46-48 They are respectively the modulation transfer function curves of the long focus, medium focus and short focus of Embodiment 4 of the athermal continuous zoom optical system of the present invention when the working temperature is 60°C.

[0036] The above drawings include the following markings:

[0037] G1, first lens; G2, second lens; G3, third lens; G4, fourth lens; G5, fifth lens; G6, sixth lens; G7, seventh lens; G8, eighth lens; G9, ninth lens; G10, tenth lens; G11, eleventh lens; G12, twelfth lens; G13, thirteenth lens; G14, fourteenth lens; IMG, target surface. DETAILED DESCRIPTION

[0038] The present invention is further described in detail below with reference to the accompanying drawings and embodiments.

[0039] The athermal continuous zoom optical system of the present invention is composed of a front fixed lens group with positive optical power, a variable magnification lens group with negative optical power, a compensating lens group with positive optical power, a rear fixed lens group with negative optical power and a target surface IMG, which are arranged in sequence along the optical axis from the object side to the image side.

[0040] The relationship between the focal length f1 of the front fixed lens group, the focal length f2 of the zoom lens group, the focal length f3 of the compensation lens group, the focal length f4 of the rear fixed lens group and the shortest focal length fs is:

[0041] 8.81<f1 / fs<9.03; -1.93<f2 / fs<-1.86; 2.00<f3 / fs<2.10; -20.00<f4 / fs<-7.20;

[0042] The total length TL1 of the front fixed lens group on the optical axis, the total length TL2 of the zoom lens group on the optical axis, the total length TL3 of the compensation lens group on the optical axis, the total length TL4 of the rear fixed lens group on the optical axis, and the total length TTL of the optical system satisfy the relationship:

[0043] 0.11<TL1 / TTL<0.15; 0.077<TL2 / TTL<0.080; 0.043<TL3 / TTL<0.055; 0.095<TL4 / TTL<0.118.

[0044] The front fixed lens group consists of a first lens, a second lens and a third lens arranged in sequence from the object side to the image side; the zoom lens group consists of a fourth lens, a fifth lens and a sixth lens arranged in sequence from the object side to the image side; the compensation lens group consists of a seventh lens, an eighth lens, a ninth lens and a tenth lens arranged in sequence from the object side to the image side; the rear fixed lens group consists of an eleventh lens, a twelfth lens, a thirteenth lens and a fourteenth lens arranged in sequence from the object side to the image side; TTL is the distance between the front surface of the first lens and the image plane on the optical axis, TL1 is the distance between the front surface of the first lens and the rear surface of the third lens on the optical axis; TL2 is the distance between the front surface of the fourth lens and the rear surface of the sixth lens on the optical axis; TL3 is the distance between the front surface of the seventh lens and the rear surface of the tenth lens on the optical axis; TL4 is the distance between the front surface of the eleventh lens and the rear surface of the fourteenth lens on the optical axis.

[0045] The thickness of the first lens is 3.80mm~4.50mm, the thickness of the second lens is 1.05mm~1.40mm, the thickness of the third lens is 9.01mm~12.76mm, the thickness of the fourth lens is 1.00mm~1.05mm, the thickness of the fifth lens is 5.00mm~5.22mm, the thickness of the sixth lens is 1.20mm~1.50mm, the thickness of the seventh lens is 1.48mm~1.81mm, the thickness of the eighth lens is 1.00mm~1.04mm, the thickness of the ninth lens is 2.12mm~2.18mm, the thickness of the tenth lens is 1.02mm~1.27mm, the thickness of the eleventh lens is 1.18mm~1.66mm, the thickness of the twelfth lens is 1.00mm~1.13mm, the thickness of the thirteenth lens is 0.88mm~1.06mm, and the thickness of the fourteenth lens is 2.66mm~2.90mm.

[0046] The air gap between the first lens and the second lens is 0.13mm~0.46mm, the air gap between the second lens and the third lens is 1.26mm~1.80mm, the air gap between the third lens and the fourth lens is 1.50mm~48.98mm, 47.03mm~48.98mm at long focus, 38.98mm~40.75mm at medium focus, and 1.50mm~2.59mm at short focus; the air gap between the fourth lens and the fifth lens is 0, the air gap between the fifth lens and the sixth lens is 3.38mm~3.60mm, the air gap between the sixth lens and the seventh lens is 0.97mm~65.87mm, 0.97mm~1.05mm at long focus, 15.69mm~16.36mm at medium focus, and 63.44mm~16.36mm at short focus. The air distance between the seventh lens and the eighth lens is 0.11mm~0.46mm, the air distance between the eighth lens and the ninth lens is 0.28mm~1.16mm, the air distance between the ninth lens and the tenth lens is 0~0.15mm, the air distance between the tenth lens and the eleventh lens is 1.09mm~22.02mm, the air distance between the telephoto lens and the eleventh lens is 17.71mm~22.02mm, the air distance between the medium focal length and the short focal length is 11.06mm~14.74mm, the air distance between the eleventh lens and the twelfth lens is 5.33mm~7.63mm, the air distance between the twelfth lens and the thirteenth lens is 1.10mm~1.39mm, and the air distance between the thirteenth lens and the fourteenth lens is 0.14mm~0.23mm.

[0047] The first lens, the second lens, the third lens, the fourth lens, the fifth lens, the sixth lens, the seventh lens, the eighth lens, the ninth lens, the tenth lens, the eleventh lens, the twelfth lens, the thirteenth lens and the fourteenth lens are all glass spherical lenses, and their refractive indices n1, n2, ..., n14 and Abbe numbers v1, v2, ..., v14 respectively satisfy the following relationship:

[0048] 1.48<n1<1.56, 1.60<n2<1.63, 1.59<n3<1.60, 1.64<n4 <1.67, 1.80<n5<1.85, 1.61<n6<1.63, 1.43<n7<1.46, 1. 85<n8<1.96, 1.49<n9<1.60, 1.74<n10<1.78, 1.61<n11< 1.65, 1.51<n12<1.53, 1.85<n13<1.86, 1.61<n14<1.63;

[0049] 59.50<v1<70.60, 35.50<v2<38.30, 67.00<v3<69.00, 54.50<v4 <60.50, 23.50<v5<25.60, 55.50<v6<56.80, 90.10<v7<95.00, 31 .20<v8<32.50, 68.20<v9<82.00, 49.20<v10<49.65, 33.50<v11< 37.20, 58.50<v12<64.50, 30.00<v13<32.50, 35.50<v14<36.80.

[0050] The first lens is made of crown glass material, such as H-K9LA, barium crown glass material H-BAK2, H-BAK4 or light crown glass material H-QK3L; the second lens is made of flint glass material, such as H-F3, H-F13, F14HT or F2G12; the third lens is made of crown glass material, such as heavy phosphorus crown glass material H-ZPK5 or H-ZPK3; the fourth lens is made of crown glass material, such as lanthanum crown glass material H-LAK11, H-LAK1 or H-LAK4L; the fifth lens is made of flint glass material, such as heavy flint glass material H-ZF7LA or H-ZF52; the sixth lens is made of crown glass material, such as heavy crown glass material H-ZK5 or H-ZK10; the seventh lens is made of crown glass material, such as fluorine crown glass material H-FK95N or H-FK71 ; The eighth lens uses a flint glass material, such as heavy lanthanum flint glass material H-ZLAF75B, H-ZLAF71 or H-ZLAF89L; the ninth lens uses a crown glass material, such as heavy phosphorus crown glass material H-ZPK5 or fluorine crown glass material H-FK61; the tenth lens uses a flint glass material, such as lanthanum flint glass material H-LAF53 or H-LAF50B; the eleventh lens uses a flint glass material, such as H-F2, H-F5, H-F13 or heavy flint glass material H-ZF1; the twelfth lens uses a crown glass material, such as H-K9LA or H-K51; the thirteenth lens uses a flint glass material, such as heavy lanthanum flint glass material H-ZLAF71 or H-ZLAF76; the fourteenth lens uses a flint glass material, such as H-F3, H-F4 or H-F5.

[0051] The front surface of the seventh lens is the aperture of the optical system, and there is no need to add an additional mechanical aperture; when the focal length changes from the shortest focal length to the longest focal length, the front fixed lens group and the rear fixed lens group are fixed, and the magnification lens group moves along the optical axis from the object side to the image side to achieve the magnification change of the system, and at the same time the compensation lens group moves along the optical axis from the image side to the object side to compensate for the offset of the image plane; when the focal length changes from the longest focal length to the shortest focal length, the front fixed lens group and the rear fixed lens group are fixed, and the magnification lens group moves along the optical axis from the image side to the object side to achieve the magnification change of the system, and at the same time the compensation lens group moves along the optical axis from the object side to the image side to compensate for the offset of the image plane.

[0052] The athermal continuous zoom optical system of the present invention is described in detail below with reference to specific embodiments.

[0053] Example 1: Figure 1 to Figure 3 As shown, in this embodiment, the first lens is a biconvex lens with positive focal power, the second lens is a meniscus lens with negative focal power, with the convex surface facing the object side and the concave surface facing the image side, the third lens is a meniscus lens with positive focal power, with the convex surface facing the object side and the concave surface facing the image side; the fourth lens and the fifth lens form a first cemented lens group, the fourth lens is a biconcave lens with negative focal power, the fifth lens is a meniscus lens with positive focal power, with the convex surface facing the object side and the concave surface facing the image side, the sixth lens is a biconcave lens with negative focal power; the seventh lens is a biconvex lens with positive focal power, and the eighth lens is a meniscus lens with negative focal power, with the convex surface facing the object side and the concave surface facing the image side, the ninth lens is a double convex lens with positive focal power, the tenth lens is a meniscus lens with negative focal power, with the convex surface facing the image side and the concave surface facing the object side; the ninth lens and the tenth lens form a second cemented lens group; the eleventh lens is a meniscus lens with negative focal power, with the convex surface facing the image side and the concave surface facing the object side, the twelfth lens is a meniscus lens with negative focal power, with the convex surface facing the object side and the concave surface facing the image side, the thirteenth lens is a double concave lens with negative focal power, and the fourteenth lens is a double convex lens with positive focal power.

[0054] The specific parameters of each lens in this embodiment are shown in Table 1.

[0055] Table 1

[0056] In this embodiment, the focal lengths of the long focus, medium focus, and short focus, the air gap d1 between the third lens and the fourth lens on the optical axis, the air gap d2 between the sixth lens and the seventh lens on the optical axis, the air gap d3 between the tenth lens and the eleventh lens on the optical axis, and the air gap d4 between the fourteenth lens and the target surface on the optical axis are as shown in Table 2.

[0057] Table 2

[0058] In this embodiment, the focal length f1 of the front fixed lens group, the focal length f2 of the zoom lens group, the focal length f3 of the compensation lens group, the focal length f4 of the rear fixed lens group and the shortest focal length fs satisfy the relationship, and the total length TL1 of the front fixed lens group on the optical axis, the total length TL2 of the zoom lens group on the optical axis, the total length TL3 of the compensation lens group on the optical axis, the total length TL4 of the rear fixed lens group on the optical axis and the total length TTL of the optical system are as shown in Table 3.

[0059] Table 3

[0060] In this embodiment, the operating wavelength band of the continuous zoom optical system is 450-900 nm, the F number is 3.9-6.2, it can be adapted to 2 / 3", 1 / 2", 1 / 1.7" detectors, and the operating temperature is -40°C to 60°C. Figures 4 to 12 It is the optical transfer function curve (MTF) of the optical system at long focus, medium focus and short focus when the optical system works in the temperature range of -40℃~60℃. The MTF curve can comprehensively reflect the imaging properties of the optical system and is the simplest and most intuitive method for evaluating image quality. The horizontal axis of the MTF curve represents the spatial frequency, and the unit is the number of line pairs / mm. The vertical axis represents the modulation amount. The smaller the modulation amount, the worse the spatial resolution. As can be seen from the figure, the MTF curve at different temperatures with the same focal length changes little, indicating that the temperature has little effect on the imaging quality of the optical system. Clear imaging can be achieved without focusing at different ambient temperatures, and it has a non-thermal function.

[0061] Example 2: Figure 13 to Figure 15 As shown, the difference between this embodiment and embodiment 1 is that the third lens is a biconvex lens with positive optical power.

[0062] The specific parameters of each lens in this embodiment are shown in Table 4.

[0063] Table 4

[0064] In this embodiment, the focal lengths of the long focus, medium focus, and short focus, the air gap d1 between the third lens and the fourth lens on the optical axis, the air gap d2 between the sixth lens and the seventh lens on the optical axis, the air gap d3 between the tenth lens and the eleventh lens on the optical axis, and the air gap d4 between the fourteenth lens and the target surface on the optical axis are as shown in Table 5.

[0065] Table 5

[0066] In this embodiment, the focal length f1 of the front fixed lens group, the focal length f2 of the zoom lens group, the focal length f3 of the compensation lens group, the focal length f4 of the rear fixed lens group and the shortest focal length fs satisfy the relationship, and the total length TL1 of the front fixed lens group on the optical axis, the total length TL2 of the zoom lens group on the optical axis, the total length TL3 of the compensation lens group on the optical axis, the total length TL4 of the rear fixed lens group on the optical axis and the total length TTL of the optical system are as shown in Table 6.

[0067] Table 6

[0068] In this embodiment, the operating wavelength band of the continuous zoom optical system is 450-900 nm, the F number is 3.9-6.2, it can be adapted to 2 / 3", 1 / 2", 1 / 1.7" detectors, and the operating temperature is -40°C to 60°C. Figure 16 to Figure 24 It is the optical transfer function curve (MTF) at long focus, medium focus and short focus when the optical system works in the temperature range of -40℃ ~ 60℃. It can be seen from the figure that the MTF curve at different temperatures with the same focal length changes little, indicating that temperature has little effect on the imaging quality of the optical system. Clear imaging can be achieved without focusing at different ambient temperatures, and it has the function of athermalization.

[0069] Example 3: Figure 25 to Figure 27 As shown, the difference between this embodiment and Embodiment 1 is that the third lens is a double convex lens with positive focal power; the ninth lens is a meniscus lens with positive focal power, with the convex surface facing the object side and the concave surface facing the image side; the tenth lens is a meniscus lens with positive focal power, with the convex surface facing the object side and the concave surface facing the image side; the eleventh lens is a meniscus lens with positive focal power, with the convex surface facing the image side and the concave surface facing the object side.

[0070] The specific parameters of each lens in this embodiment are shown in Table 7.

[0071] Table 7

[0072] In this embodiment, the focal lengths of the long focus, medium focus, and short focus, the air gap d1 between the third lens and the fourth lens on the optical axis, the air gap d2 between the sixth lens and the seventh lens on the optical axis, the air gap d3 between the tenth lens and the eleventh lens on the optical axis, and the air gap d4 between the fourteenth lens and the target surface on the optical axis are as shown in Table 8.

[0073] Table 8

[0074] In this embodiment, the focal length f1 of the front fixed lens group, the focal length f2 of the zoom lens group, the focal length f3 of the compensation lens group, the focal length f4 of the rear fixed lens group and the shortest focal length fs satisfy the relationship, and the total length TL1 of the front fixed lens group on the optical axis, the total length TL2 of the zoom lens group on the optical axis, the total length TL3 of the compensation lens group on the optical axis, the total length TL4 of the rear fixed lens group on the optical axis and the total length TTL of the optical system are as shown in Table 9.

[0075] Table 9

[0076] In this embodiment, the operating wavelength band of the continuous zoom optical system is 450-900 nm, the F number is 3.9-6.2, it can be adapted to 2 / 3", 1 / 2", 1 / 1.7" detectors, and the operating temperature is -40°C to 60°C. Figure 28 to Figure 36 It is the optical transfer function curve (MTF) at long focus, medium focus and short focus when the optical system works in the temperature range of -40℃ ~ 60℃. It can be seen from the figure that the MTF curve at different temperatures with the same focal length changes little, indicating that temperature has little effect on the imaging quality of the optical system. Clear imaging can be achieved without focusing at different ambient temperatures, and it has the function of athermalization.

[0077] Example 4: Figure 37 to Figure 39 As shown, the difference between this embodiment and embodiment 1 is that the third lens is a biconvex lens with positive focal power; the ninth lens and the tenth lens are single lenses respectively, the ninth lens is a meniscus lens with positive focal power, with the convex surface facing the object side and the concave surface facing the image side, the tenth lens is a meniscus lens with positive focal power, with the convex surface facing the object side and the concave surface facing the image side; the thirteenth lens is a meniscus lens with negative focal power, with the convex surface facing the object side and the concave surface facing the image side.

[0078] The specific parameters of each lens in this embodiment are shown in Table 10.

[0079] Table 10

[0080] In this embodiment, the focal lengths of the long focus, medium focus, and short focus, the air gap d1 between the third lens and the fourth lens on the optical axis, the air gap d2 between the sixth lens and the seventh lens on the optical axis, the air gap d3 between the tenth lens and the eleventh lens on the optical axis, and the air gap d4 between the fourteenth lens and the target surface on the optical axis are as shown in Table 11.

[0081] Table 11

[0082] In this embodiment, the focal length f1 of the front fixed lens group, the focal length f2 of the zoom lens group, the focal length f3 of the compensation lens group, the focal length f4 of the rear fixed lens group and the shortest focal length fs satisfy the relationship, and the total length TL1 of the front fixed lens group on the optical axis, the total length TL2 of the zoom lens group on the optical axis, the total length TL3 of the compensation lens group on the optical axis, the total length TL4 of the rear fixed lens group on the optical axis and the total length TTL of the optical system are as shown in Table 12.

[0083] Table 12

[0084] In this embodiment, the operating wavelength band of the continuous zoom optical system is 450-900 nm, the F number is 3.9-6.2, it can be adapted to 2 / 3", 1 / 2", 1 / 1.7" detectors, and the operating temperature is -40°C to 60°C. Figures 40 to 48 It is the optical transfer function curve (MTF) at long focus, medium focus and short focus when the optical system works in the temperature range of -40℃ ~ 60℃. It can be seen from the figure that the MTF curve at different temperatures with the same focal length changes little, indicating that temperature has little effect on the imaging quality of the optical system. Clear imaging can be achieved without focusing at different ambient temperatures, and it has the function of athermalization.

Claims

1. An athermal continuous zoom optical system, characterized in that: The system consists of a front fixed lens group with positive focal power, a zoom lens group with negative focal power, a compensating lens group with positive focal power, a rear fixed lens group with negative focal power, and a target surface, which are arranged in sequence along the optical axis from the object side to the image side; the focal length f1 of the front fixed lens group, the focal length f2 of the zoom lens group, the focal length f3 of the compensating lens group, the focal length f4 of the rear fixed lens group and the shortest focal length fs satisfy the relationship: 8.81<f1 / fs<9.03; -1.93<f2 / fs<-1.86; 2.00<f3 / fs<2.10; -20.00<f4 / fs<-7.20; When the focal length changes from the shortest focal length to the longest focal length, the front fixed lens group and the rear fixed lens group are fixed, and the zoom lens group moves along the optical axis from the object side to the image side to achieve the system's zoom, and at the same time the compensation lens group moves along the optical axis from the image side to the object side to compensate for the offset of the image plane; when the focal length changes from the longest focal length to the shortest focal length, the front fixed lens group and the rear fixed lens group are fixed, and the zoom lens group moves along the optical axis from the image side to the object side to achieve the system's zoom, and at the same time the compensation lens group moves along the optical axis from the object side to the image side to compensate for the offset of the image plane; The front fixed lens group consists of a first lens, a second lens and a third lens arranged in sequence from the object side to the image side; the zoom lens group consists of a fourth lens, a fifth lens and a sixth lens arranged in sequence from the object side to the image side; the compensation lens group consists of a seventh lens, an eighth lens, a ninth lens and a tenth lens arranged in sequence from the object side to the image side; and the rear fixed lens group consists of an eleventh lens, a twelfth lens, a thirteenth lens and a fourteenth lens arranged in sequence from the object side to the image side.

2. The athermalized continuous zoom optical system according to claim 1, characterized in that: The total length TL1 of the front fixed lens group on the optical axis, the total length TL2 of the zoom lens group on the optical axis, the total length TL3 of the compensation lens group on the optical axis, the total length TL4 of the rear fixed lens group on the optical axis and the total length TTL of the optical system satisfy the following relationship: 0.11<TL1 / TTL<0.15; 0.077<TL2 / TTL<0.080; 0.043<TL3 / TTL<0.055; 0.095<TL4 / TTL<0.

118.

3. The athermalized continuous zoom optical system according to claim 1, wherein: The thickness of the first lens is 3.80 mm to 4.50 mm, the thickness of the second lens is 1.05 mm to 1.40 mm, the thickness of the third lens is 9.01 mm to 12.76 mm, the thickness of the fourth lens is 1.00 mm to 1.05 mm, the thickness of the fifth lens is 5.00 mm to 5.22 mm, the thickness of the sixth lens is 1.20 mm to 1.50 mm, the thickness of the seventh lens is 1.48 mm to 1.81 mm, the thickness of the eighth lens is 1.00 mm to 1.04 mm, the thickness of the ninth lens is 2.12 mm to 2.18 mm, the thickness of the tenth lens is 1.02 mm to 1.27 mm, the thickness of the eleventh lens is 1.18 mm to 1.66 mm, the thickness of the twelfth lens is 1.00 mm to 1.13 mm, the thickness of the thirteenth lens is 0.88 mm to 1.06 mm, and the thickness of the fourteenth lens is 2.66 mm to 2.90 mm.

4. The athermalized continuous zoom optical system according to claim 3, characterized in that: The air gap between the first lens and the second lens is 0.13mm-0.46mm, the air gap between the second lens and the third lens is 1.26mm-1.80mm, the air gap between the third lens and the fourth lens is 1.50mm-48.98mm, the air gap between the fourth lens and the fifth lens is 0, the air gap between the fifth lens and the sixth lens is 3.38mm-3.60mm, the air gap between the sixth lens and the seventh lens is 0.97mm-65.87mm, and the air gap between the seventh lens and the eighth lens is 0.11m m~0.46mm, the air space between the eighth lens and the ninth lens is 0.28mm~1.16mm, the air space between the ninth lens and the tenth lens is 0~0.15mm, the air space between the tenth lens and the eleventh lens is 1.09mm~22.02mm, the air space between the eleventh lens and the twelfth lens is 5.33mm~7.63mm, the air space between the twelfth lens and the thirteenth lens is 1.10mm~1.39mm, and the air space between the thirteenth lens and the fourteenth lens is 0.14mm~0.23mm.

5. The athermalized continuous zoom optical system according to claim 4, characterized in that: The air distance between the third lens and the fourth lens is 47.03mm-48.98mm at long focus, 38.98mm-40.75mm at medium focus, and 1.50mm-2.59mm at short focus; the air distance between the sixth lens and the seventh lens is 0.97mm-1.05mm at long focus, 15.69mm-16.36mm at medium focus, and 63.44mm-65.87mm at short focus; the air distance between the tenth lens and the eleventh lens is 17.71mm-22.02mm at long focus, 11.06mm-14.74mm at medium focus, and 1.09mm-2.92mm at short focus.

6. The athermalized continuous zoom optical system according to claim 3, characterized in that: The first lens, the second lens, the third lens, the fourth lens, the fifth lens, the sixth lens, the seventh lens, the eighth lens, the ninth lens, the tenth lens, the eleventh lens, the twelfth lens, the thirteenth lens and the fourteenth lens are all glass spherical lenses, and their refractive indices n1, n2, ..., n14 and Abbe numbers v1, v2, ..., v14 respectively satisfy the following relationship: 1.48<n1<1.56, 1.60<n2<1.63, 1.59<n3<1.60, 1.64<n4 <1.67, 1.80<n5<1.85, 1.61<n6<1.63, 1.43<n7<1.46, 1. 85<n8<1.96, 1.49<n9<1.60, 1.74<n10<1.78, 1.61<n11< 1.65, 1.51<n12<1.53, 1.85<n13<1.86, 1.61<n14<1.63; 59.50<v1<70.60, 35.50<v2<38.30, 67.00<v3<69.00, 54.50<v4 <60.50, 23.50<v5<25.60, 55.50<v6<56.80, 90.10<v7<95.00, 31 .20<v8<32.50, 68.20<v9<82.00, 49.20<v10<49.65, 33.50<v11< 37.20, 58.50<v12<64.50, 30.00<v13<32.50, 35.50<v14<36.

80.

7. The athermalized continuous zoom optical system according to claim 3, characterized in that: The first lens is a biconvex lens; the second lens is a meniscus lens with negative focal power, and its convex surface faces the object; the third lens is a meniscus lens with positive focal power, and its convex surface faces the object; the fourth lens and the fifth lens form a first cemented lens group, the fourth lens is a biconcave lens, the fifth lens is a meniscus lens with positive focal power, and its convex surface faces the object; the sixth lens is a biconcave lens; the seventh lens is a biconvex lens; the eighth lens is a meniscus lens with negative focal power, and its convex surface faces the object; the ninth lens is a biconvex lens; the tenth lens is a meniscus lens with negative focal power, and its convex surface faces the image; the ninth lens and the tenth lens form a second cemented lens group; the eleventh lens is a meniscus lens with negative focal power, and its convex surface faces the image; the twelfth lens is a meniscus lens with negative focal power, and its convex surface faces the object; the thirteenth lens is a biconcave lens; and the fourteenth lens is a biconvex lens.

8. The athermalized continuous zoom optical system according to claim 3, wherein: The first lens is a biconvex lens; the second lens is a meniscus lens with negative focal power, and the convex surface faces the object; the third lens is a biconvex lens; the fourth lens and the fifth lens form a first cemented lens group, the fourth lens is a biconcave lens, the fifth lens is a meniscus lens with positive focal power, and the convex surface faces the object; the sixth lens is a biconcave lens; the seventh lens is a biconvex lens; the eighth lens is a meniscus lens with negative focal power, and the convex surface faces the object; the ninth lens is a biconvex lens; the tenth lens is a meniscus lens with negative focal power, and the convex surface faces the image; the ninth lens and the tenth lens form a second cemented lens group; the eleventh lens is a meniscus lens with negative focal power, and the convex surface faces the image; the twelfth lens is a meniscus lens with negative focal power, and the convex surface faces the object; the thirteenth lens is a biconcave lens; and the fourteenth lens is a biconvex lens.

9. The athermalized continuous zoom optical system according to claim 3, wherein: The first lens is a biconvex lens; the second lens is a meniscus lens with negative focal power, and its convex surface faces the object; the third lens is a biconvex lens; the fourth lens and the fifth lens form a first cemented lens group, the fourth lens is a biconcave lens, the fifth lens is a meniscus lens with positive focal power, and its convex surface faces the object; the sixth lens is a biconcave lens; the seventh lens is a biconvex lens; the eighth lens is a meniscus lens with negative focal power, and its convex surface faces the object; the ninth lens is a meniscus lens with positive focal power, and its convex surface faces the object; the tenth lens is a meniscus lens with positive focal power, and its convex surface faces the object; the ninth lens and the tenth lens form a second cemented lens group; the eleventh lens is a meniscus lens with positive focal power, and its convex surface faces the image; the twelfth lens is a meniscus lens with negative focal power, and its convex surface faces the object; the thirteenth lens is a biconcave lens; and the fourteenth lens is a biconvex lens.

10. The athermalized continuous zoom optical system according to claim 3, characterized in that: The first lens is a biconvex lens; the second lens is a meniscus lens with negative focal power, and its convex surface faces the object; the third lens is a biconvex lens; the fourth lens and the fifth lens form a first cemented lens group, the fourth lens is a biconcave lens, the fifth lens is a meniscus lens with positive focal power, and its convex surface faces the object; the sixth lens is a biconcave lens; the seventh lens is a biconvex lens; the eighth lens is a meniscus lens with negative focal power, and its convex surface faces the object; the ninth lens and the tenth lens are single lenses respectively; the ninth lens is a meniscus lens with positive focal power, and its convex surface faces the object; the tenth lens is a meniscus lens with positive focal power, and its convex surface faces the object; the eleventh lens is a meniscus lens with negative focal power, and its convex surface faces the image; the twelfth lens is a meniscus lens with negative focal power, and its convex surface faces the object; the thirteenth lens is a meniscus lens with negative focal power, and its convex surface faces the object; and the fourteenth lens is a biconvex lens.

Images