Large-target-surface high-definition continuous zooming optical system
By designing a large-target-area high-definition continuous zoom optical system and employing lens combinations and ultra-low dispersion materials, the problems of small target area and low resolution in existing optical systems have been solved, realizing an optical system with high-definition resolution and a large target area, which is suitable for airborne high-altitude reconnaissance systems.
Patent Information
- Application Number
- CN202511037741.1
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-07-28
- Publication Date
- 2025-10-17
AI Technical Summary
The existing optical system has a small target surface and low resolution, which cannot meet the matching requirements of airborne high-altitude reconnaissance systems for high-definition cameras.
Design a large-target-area high-definition continuous zoom optical system, including a front fixed group with positive optical power, a zoom group with negative optical power, a compensation group with positive optical power, and a rear fixed group with positive optical power. The lens assembly adopts ultra-low dispersion material. The focal length change and image plane stabilization are achieved by moving the lens assembly, and various aberrations are corrected.
It achieves an optical system with an ultra-large target surface of 20mm and high-definition resolution, suitable for high-definition cameras and airborne optoelectronic systems, improving the detection and identification capabilities of long-distance targets, and is suitable for CCD or CMOS with a pixel count of 4096×4096 and a pixel size of 3.45μm×3.45μm.
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Figure CN120802477A_ABST
Abstract
Description
TECHNICAL FIELD
[0001] The application belongs to the zoom optical system of photoelectric equipment, and particularly relates to a super-large target surface high-definition continuous zoom optical system. BACKGROUND
[0002] At present, the airborne high-altitude reconnaissance system requires that the optical system has a large range target search and a small range target identification, and the demand for resolution develops from standard definition to high definition, so the optical system should have the advantages of long focal length, high resolution and large zoom ratio.
[0003] The existing optical system has a small target surface and low resolution, and cannot meet the requirements of the airborne high-altitude reconnaissance system that the optical system should have a high resolution and a large target surface. SUMMARY
[0004] In view of the problem of the small target surface and low resolution of the existing system, the application provides a super-large target surface continuous zoom optical system to solve the problem that it cannot be matched with a high-definition camera.
[0005] The technical scheme adopted by the application to solve the technical problem is as follows: a large target surface high-definition continuous zoom optical system is provided, which is sequentially provided with a front fixed group with positive focal power, a zoom group with negative focal power, a compensation group with positive focal power and a rear fixed group with positive focal power along the propagation direction of light rays from left to right, and an aperture stop is arranged between the compensation group and the rear fixed group; the front fixed group comprises a first cemented lens group and a third front fixed lens which is a plano-convex positive lens and are sequentially arranged, the first cemented lens group is composed of a first front fixed lens which is a concave negative lens facing the aperture stop and a second front fixed lens which is a biconvex positive lens; the zoom group comprises a first zoom lens, a second zoom lens and a second cemented lens group which are sequentially arranged, the first zoom lens is a concave negative lens with the concave surface facing the aperture stop, the second zoom lens is a biconcave negative lens, and the second cemented lens group is composed of a third zoom lens which is a biconcave negative lens and a fourth zoom lens which is a concave positive lens with the concave surface facing the aperture stop; the compensation group comprises a first compensation lens, a second compensation lens and a third cemented lens group which are sequentially arranged, the first compensation lens and the second compensation lens are biconvex positive lenses, and the third cemented lens group is composed of a third compensation lens which is a biconvex positive lens and a fourth compensation lens which is a plano-concave negative lens; and the rear fixed group is composed of a first rear fixed lens, a second rear fixed lens, a third rear fixed lens and a fourth rear fixed lens, the first rear fixed lens is a biconcave negative lens, the second rear fixed lens is a convex positive lens with the convex surface facing the aperture stop, the third rear fixed lens is a convex negative lens with the convex surface facing the aperture stop, and the fourth rear fixed lens is a convex positive lens with the convex surface facing the aperture stop.
[0006] Further, the air gap between the front fixed group and the variable group is 4-71.48mm, the air gap between the variable group and the compensation group is 91.38-1.0mm, and the air gap between the compensation group and the rear fixed group is 3.1-26mm.
[0007] Further, at least one of the first front fixed lens, the second front fixed lens and the third front fixed lens is made of ultra-low dispersion optical material, such as H-FK61, H-FK71 or CaF2 optical material.
[0008] Further, the gap between the first cemented lens group and the third front fixed lens is 0.2mm, the gap between the first variable lens and the second variable lens is 6.26mm, and the gap between the second variable lens and the second cemented lens group is 5.10mm.
[0009] Further, the gap between the first compensation lens and the second compensation lens is 16.97mm, and the gap between the second compensation lens and the third cemented lens group is 0.2mm.
[0010] Further, the air gap between the first rear fixed lens and the second rear fixed lens is 4.86mm, the air gap between the second rear fixed lens and the third rear fixed lens is 12mm, and the air gap between the third rear fixed lens and the fourth rear fixed lens is 16mm.
[0011] The present application provides a continuous zoom optical system working in the visible light band, which adopts 15 lenses, all surfaces of all lenses are spherical surfaces, the super large target surface is 20mm, and is suitable for high-definition CCD or CMOS with a pixel number of 4096*4096 and a pixel size of 3.45*3.45um.
[0012] Compared with the prior art, the resolution of the optical system is greatly improved, and the optical system is suitable for high-definition cameras and some airborne photoelectric systems with strict requirements on resolution, and the focal length of the optical system is 24.5-202mm, so that the detection and identification of long-distance targets are greatly improved, and the application range is very wide. BRIEF DESCRIPTION OF DRAWINGS
[0013] Figure 1 Schematic view of components of the optical structure; Figure 2 Optical system in short-focus state; Figure 3 Optical system in medium-focus state; Figure 4 Optical system in long-focus state; Figure 5Optical system in short focus state at spatial frequency 100 lp / mm transfer function diagram; Figure 6 Optical system in mid focus state at spatial frequency 100 lp / mm transfer function diagram; Figure 7 Optical system in long focus state at spatial frequency 100 lp / mm transfer function diagram; Figure 8 Optical system in short focus state at field curvature distortion diagram; Figure 9 Optical system in mid focus state at field curvature distortion diagram; Figure 10 Optical system in long focus state at field curvature distortion diagram.
[0014] The reference signs are as follows: A - front fixed group, A1 - first front fixed lens, A2 - second front fixed lens, A3 - third front fixed lens, B - zoom group, B1 - first zoom lens, B2 - second zoom lens, B3 - third zoom lens, B4 - fourth zoom lens, C - compensation group, C1 - first compensation lens, C2 - second compensation lens, C3 - third compensation lens, C4 - fourth compensation lens, D - rear fixed group, D1 - first rear fixed lens, D2 - second rear fixed lens, D3 - third rear fixed lens, D4 - fourth rear fixed lens, ST - stop. DETAILED DESCRIPTION
[0015] In order to make the objectives, technical solutions and advantages of the present application clearer, the present application will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and should not be used to limit the present application.
[0016] Reference Figure 1As shown, the large target surface high-definition continuous zoom optical system disclosed by the embodiment of the present application comprises a front fixed group A with positive focal power, a zoom group B with negative focal power, a compensation group C with positive focal power and a rear fixed group D with positive focal power in sequence along the light propagation direction of the light rays incident into the optical system from the object side, and a diaphragm ST is arranged on the optical path between the compensation group C and the rear fixed group D. The air gap between the front fixed group A and the zoom group B is 4-71.48 mm, the air gap between the zoom group B and the compensation group C is 91.38-1.0 mm, and the air gap between the compensation group C and the rear fixed group D is 3.1-26 mm. In addition, the interval between the first cemented lens group and the third front fixed lens A3 is 0.2 mm; the interval between the first zoom lens B1 and the second zoom lens B2 is 6.26 mm; the interval between the second zoom lens B2 and the second cemented lens group is 5.10 mm; the interval between the first compensation lens C1 and the second compensation lens C2 is 16.97 mm; the interval between the second compensation lens C2 and the third cemented lens group is 0.2 mm; the air gap between the first rear fixed lens D1 and the second rear fixed lens D2 is 4.86 mm; the air gap between the second rear fixed lens D2 and the third rear fixed lens D3 is 12 mm; and the air gap between the third rear fixed lens D3 and the fourth rear fixed lens D4 is 16 mm.
[0017] The front fixed group A is composed of three lenses, i.e., the first front fixed lens A1 is a negative lens with a concave surface facing the diaphragm ST, the second front fixed lens A2 is a double-convex positive lens, and the third front fixed lens A3 is a plano-convex positive lens, wherein the negative lens and the double-convex positive lens form a first cemented lens group.
[0018] The zoom group B is composed of four lenses, i.e., the first zoom lens B1 is a negative lens with a concave surface facing the diaphragm ST, the second zoom lens B2 is a double-concave negative lens, the third zoom lens B3 is a double-concave negative lens, and the fourth zoom lens B4 is a positive lens with a concave surface facing the diaphragm ST, wherein the third zoom lens B3 and the fourth zoom lens B4 form a second cemented lens group.
[0019] The compensation group C is composed of four lenses, i.e., the first compensation lens C1 is a double-convex positive lens, the second compensation lens C2 is a double-convex positive lens, the third compensation lens C3 is a double-convex positive lens, and the fourth compensation lens C4 is a plano-concave negative lens, wherein the third compensation lens C3 and the fourth compensation lens C4 form a third cemented lens group.
[0020] The rear fixed group D is composed of four lenses, i.e., the first rear fixed lens D1 is a double-concave negative lens, the second rear fixed lens D2 is a positive lens with a convex surface facing the diaphragm ST, the third rear fixed lens D3 is a negative lens with a convex surface facing the diaphragm ST, and the fourth rear fixed lens D4 is a positive lens with a convex surface facing the diaphragm ST.
[0021] In order to realize higher resolution, a cemented lens group and a positive lens are arranged in the front fixed group A, two positive lenses bending to the diaphragm are made of super low dispersion optical material, so that the secondary spectrum aberration is effectively reduced, and the resolution of the lens is significantly improved. Compared with ordinary optical lens, the lens can adapt to larger target surface and higher resolution, and is suitable for complex airborne conditions and some photoelectric devices with strict requirements on resolution.
[0022] The technical index realized by the optical system is that the working waveband is a visible light waveband, the optical system F#:4, the focal length is 24.5-202mm, the super large target surface is 20mm, the adaptive pixel number is 4096x4096, and the pixel size is 3.45umx3.45um of a CCD or CMOS.
[0023] The optical system utilizes the front fixed group A to correct various aberrations of the long focus, the first cemented lens group and the third front fixed lens A3 are added in the front fixed group A, and the radius of curvature and the air gap are utilized to correct the aberration of the long focus end. At least one lens in the three lenses in the front fixed group A is selected from H-FK61, H-FK71 or CaF2 and the like super low dispersion optical material, which is used to reduce the secondary spectrum and the like aberration of the optical system at a long angle. In the optical system, 15 lenses are adopted, all the surfaces of all the lenses are spherical surfaces, and domestic materials are adopted for the lens materials, so that the optical system is easy to process and manufacture and low in cost.
[0024] The optical system realizes the change of the focal length through the relative movement of the zoom group B and the compensation group C. When the focal length changes from the short focus to the long focus, the zoom group B moves backward relative to the front fixed group A, the compensation group C moves backward relative to the rear fixed group D, and the two groups move relative to each other according to different movement rules to compensate the movement of the image surface, so that the effect of keeping the image surface stable is achieved.
[0025] When the distance of the measured target changes, the system is defocused, so the optical system needs to be focused, and the lens in the rear fixed group D is moved to realize the focusing of the optical system, so that the image surface is located on the focal plane of the detector.
[0026] The function of the zoom group B is mainly to correct chromatic aberration, the second cemented lens group is added in the zoom group B for correcting chromatic aberration, the first zoom lens B1 and the second zoom lens B2 are added in front of the cemented lens, that is, the structure form of the negative lens in front and the cemented lens behind. The light rays borne by the cemented lens are the divergent light rays passing through the first zoom lens B1 and the second zoom lens B2, and the incidence angle of the light rays in the cemented lens group is reduced, and then the aberration is reduced.
[0027] The focal length of the compensation group C should not be too short or too long. If it is too short, the relative aperture of the compensation group C is too large, and if it is too long, the compensation amount required for the compensation of the image surface displacement is too large, and the aberration correction is difficult. Generally, the focal length of the compensation group C is controlled to be about 2.5 times of the focal length of the variable magnification group B.
[0028] As shown in Figure 2 , Figure 3 , Figure 4 , Figure 2 is an optical system in a short-focus state, Figure 3 is an optical system in a medium-focus state, Figure 4 is an optical system in a long-focus state.
[0029] The transfer function diagram of the optical system at a spatial frequency of 100 lp / mm is shown in Figure 5 , Figure 6 , Figure 7 , Figures 5 to 7 It can be seen that the minimum transfer function of the system in each field of view is 0.2.
[0030] The field curvature distortion of the optical system is shown in Figure 8 , Figure 9 , Figure 10 , Figures 8 to 10 It can be seen that the distortion is less than 3% in the large field of view.
[0031] The optical parameters of each lens of the optical system are shown in the following table.
[0032]
[0033] It should be understood that, for those skilled in the art, improvements or changes can be made according to the above description, and all these improvements and changes shall belong to the protection scope of the appended claims of the present application.
Claims
1. A large-area, high-definition, continuous zoom optical system, characterized by: Along the propagation direction of the light, a front fixed group (A) with positive optical power, a zoom group (B) with negative optical power, a compensation group (C) with positive optical power, and a rear fixed group (D) with positive optical power are sequentially arranged, and a stop (ST) is provided between the compensation group (C) and the rear fixed group (D); The front fixed group (A) comprises a first cemented lens group and a third front fixed lens (A3) of a plano-convex positive lens arranged in sequence, wherein the first cemented lens group comprises a first front fixed lens (A1) having a concave surface and a negative lens, and a second front fixed lens (A2) of a biconvex positive lens; The zoom group (B) comprises a first zoom lens (B1), a second zoom lens (B2), and a second cemented lens group arranged in sequence, wherein the first zoom lens (B1) is a negative lens with a concave curved aperture (ST), the second zoom lens (B2) is a double-concave negative lens, and the second cemented lens group comprises a third zoom lens (B3) which is a double-concave negative lens, a fourth zoom lens (B4) which is a concave curved aperture (ST), and a positive lens; The compensation group (C) includes a first compensation lens (C1), a second compensation lens (C2), and a third cemented lens group arranged in sequence, the first compensation lens (C1) and the second compensation lens (C2) are biconvex positive lenses, and the third cemented lens group is composed of a third compensation lens (C3) which is a biconvex positive lens and a fourth compensation lens (C4) which is a plano-concave negative lens; The rear fixed group (D) is composed of a first rear fixed lens (D1), a second rear fixed lens (D2), a third rear fixed lens (D3) and a fourth rear fixed lens (D4). The first rear fixed lens (D1) is a biconcave negative lens, the second rear fixed lens (D2) is a positive lens with a convex surface curved toward the aperture (ST), the third rear fixed lens (D3) is a negative lens with a convex surface curved toward the aperture (ST), and the fourth rear fixed lens (D4) is a positive lens with a convex surface facing the aperture (ST).
2. The large-area, high-definition, continuous zoom optical system according to claim 1, characterized in that: The air gap between the front fixing group (A) and the zoom group (B) is 4 to 71.48 mm, the air gap between the zoom group (B) and the compensation group (C) is 91.38 to 1.0 mm, and the air gap between the compensation group (C) and the rear fixing group (D) is 3.1 to 26 mm.
3. A large-surface, high-definition, continuous zoom optical system according to claim 1 or 2, characterized in that: At least one of the first front fixed lens (A1), the second front fixed lens (A2) and the third front fixed lens (A3) is made of H-FK61, H-FK71 or CaF2 optical material.
4. The large-area, high-definition, continuous zoom optical system according to claim 3, characterized in that: The interval between the first cemented lens group and the third front fixed lens (A3) is 0.2 mm; the interval between the first variable magnification lens (B1) and the second variable magnification lens (B2) is 6.26 mm; and the interval between the second variable magnification lens (B2) and the second cemented lens group is 5.10 mm.
5. The large-area, high-definition, continuous zoom optical system according to claim 3, characterized in that: The distance between the first compensating lens (C1) and the second compensating lens (C2) is 16.97 mm; the distance between the second compensating lens (C2) and the third cemented lens group is 0.2 mm.
6. The large-area, high-definition, continuous zoom optical system according to claim 3, characterized in that: The air gap between the first rear fixed lens (D1) and the second rear fixed lens (D2) is 4.86 mm; the air gap between the second rear fixed lens (D2) and the third rear fixed lens (D3) is 12 mm; and the air gap between the third rear fixed lens (D3) and the fourth rear fixed lens (D4) is 16 mm.