Large-aperture zoom objective lens for infrared polarization imaging system

Abstract

The invention discloses a large-aperture zoom objective lens for an infrared polarization imaging system, and relates to the technical field of optical system imaging. The compensation mode of the zoom objective optical system provided by the invention adopts a full-motion compensation mode, and the first zoom group G1, the second zoom group G2, the first compensation group G3 and the second compensation group G4 move independently to realize the purposes of changing the focal length of the optical system and keeping the position of an image plane unchanged. In the design process, the optical surfaces of all lenses in the zoom objective optical system adopt spherical design. The large-aperture zoom objective lens for the infrared polarization imaging system has the advantages of being large in aperture, very high in imaging quality, high in relative illumination, good in image plane uniformity, loose in machining and adjustment tolerance and the like.

Description

Technical Field

[0001] The invention relates to the technical field of optical system imaging, and in particular to a large-aperture zoom objective lens used in an infrared polarization imaging system. Background Art

[0002] As a new type of optical imaging technology, polarization imaging technology can obtain polarization information of different targets in different bands, and can achieve functions such as suppressing background noise, increasing detection distance, obtaining target details and identifying camouflaged targets. It is widely used in target detection and identification, remote sensing detection, industrial detection and biomedical detection. The polarization imaging system uses polarization imaging technology to reconstruct the target image. The structure includes imaging lens, polarization analyzer and imaging detector. The imaging lens is the core component of the polarization imaging system, which directly undertakes the task of obtaining target light information.

[0003] The focal length of a zoom optical system can be changed continuously within a certain range, and a clearer image can be obtained while the position of the system image plane remains unchanged. It can clearly observe different parts of an object without changing the position of the object by enlarging or reducing the focal length of the optical system. By changing the magnification, global observation and local precise detection of the object can be achieved, which are functions that a single fixed-focus optical system cannot have. The currently designed large-aperture zoom objective for polarization imaging works in the short-wave infrared band. The aberrations of this type of optical system are often difficult to correct, so its current design often uses aspherical surfaces to increase the design freedom to correct the system aberrations, but this will lead to production and assembly costs; therefore, providing a large-aperture zoom objective for polarization imaging with good imaging quality and simple structure has very important practical application value. Summary of the invention

[0004] The purpose of the present invention is to propose a large-aperture zoom objective lens for an infrared polarization imaging system to solve the problems raised in the background technology. Compared with the existing design, the present invention has the characteristics of large aperture, very high imaging quality, high relative illumination, good image surface uniformity, and loose processing and adjustment tolerances.

[0005] To achieve the above object, the present invention provides the following solutions:

[0006] The present invention is based on the design principle of zoom optical system and the aberration analysis method. On the basis of determining the initial structure of the optical system, the present invention uses optical design software to design a large aperture zoom objective lens for polarization imaging system. In the design process, the optical surfaces of all lenses are designed with spherical surfaces, and finally a large aperture zoom objective lens with good imaging quality is achieved. The specific contents include the following:

[0007] The zoom objective lens comprises a first zoom group with positive optical power, a second zoom group with negative optical power, a first compensation group with positive optical power, and a second compensation group with positive optical power, which are arranged in sequence from the object side to the image side;

[0008] The first zoom group is composed of a first lens with positive focal power, a second lens with negative focal power, and a third lens with positive focal power;

[0009] The second zoom group is composed of a fourth lens with negative optical power, a fifth lens with negative optical power, and a sixth lens with positive optical power;

[0010] The first compensation group is composed of a seventh lens with positive focal power, an eighth lens with negative focal power, a ninth lens with negative focal power, and a tenth lens with positive focal power;

[0011] The second compensation group consists of an 11th lens with negative optical power, a 12th lens with positive optical power, a 13th lens with negative optical power and a 14th lens with positive optical power.

[0012] Preferably, the optical surface of the first lens facing the object side is convex toward the object side, and the optical surface facing the image side is convex toward the image side; the optical surface of the second lens facing the object side is convex toward the image side, and the optical surface facing the image side is convex toward the object side; the optical surfaces of the third lens facing the object side and the image side are both convex toward the object side; wherein the first lens and the second lens are double-cemented lenses.

[0013] Preferably, the optical surfaces of the fourth lens facing the object side and the image side are both convex toward the object side; the optical surface of the fifth lens facing the object side is convex toward the image side, and the optical surface facing the image side is convex toward the object side; the optical surfaces of the sixth lens facing the object side and the image side are both convex toward the object side; wherein the fifth lens and the sixth lens are double-cemented lenses.

[0014] Preferably, the optical surface of the 7th lens facing the object side is convex towards the object side, and the optical surface facing the image side is convex towards the image side; the optical surface of the 8th lens facing the object side is convex towards the image side, and the optical surface facing the image side is convex towards the object side; the optical surface of the 9th lens facing the object side is convex towards the object side, and the optical surface facing the image side is convex towards the image side; the optical surface of the 10th lens facing the object side is convex towards the object side, and the optical surface facing the image side is convex towards the image side; wherein, the 8th lens and the 9th lens are double-cemented lenses.

[0015] Preferably, the optical surfaces of the 11th lens facing the object side and the image side are both convex toward the image side; the optical surface of the 12th lens facing the object side is convex toward the object side, and the optical surface facing the image side is convex toward the image side; the optical surfaces of the 13th lens facing the object side and the image side are both convex toward the object side; the optical surfaces of the 14th lens facing the object side and the image side are both convex toward the object side.

[0016] Preferably, an aperture stop is provided between the 12th lens and the 13th lens.

[0017] Preferably, the optical surfaces of all lenses in the zoom objective are spherical in design; the first zoom group, the second zoom group, the first compensation group and the second compensation group move independently to achieve the purpose of changing the focal length of the optical system and keeping the image plane position unchanged.

[0018] Preferably, the focal length variation range of the zoom objective lens is 12 mm to 80 mm, the corresponding maximum field angle range is 28.1° to 4.3°, the F / # value is 4, the detected wavelength range is 900 nm to 1100 nm, and the main wavelength is 1000 nm.

[0019] Preferably, the materials used for 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 724442.464637, 754892.275920, 642057.526629, and 63910 respectively. 2.568686, 563200.637232, 755201.275795, 664977.519714, 676542.316563, 648228.515702, 638444.540739, 747065.279163, 569291.508986, 740815.281858, 642104.563677.

[0020] Preferably, when the focal length of the zoom objective lens is 12 mm, the distance between the first magnification group and the second magnification group is 1 mm, the distance between the second magnification group and the first compensation group is 102.27 mm, and the distance between the first compensation group and the second compensation group is 2.24 mm; when the focal length of the zoom objective lens is 48 mm, the distance between the first magnification group and the second magnification group is 42.69 mm, the distance between the second magnification group and the first compensation group is 23.69 mm, and the distance between the first compensation group and the second compensation group is 14.92 mm; when the focal length of the zoom objective lens is 80 mm, the distance between the first magnification group and the second magnification group is 50.24 mm, the distance between the second magnification group and the first compensation group is 4.49 mm, and the distance between the first compensation group and the second compensation group is 15.66 mm.

[0021] Compared with the prior art, the present invention provides a large-aperture zoom objective lens for an infrared polarization imaging system, which has the following beneficial effects:

[0022] The present invention is based on the design principle of zoom optical system and the aberration analysis method, and rationally uses the optimization function to perform aberration correction, and then applies the optical design software to repeatedly optimize it, thereby obtaining a large-aperture zoom objective lens for infrared polarization imaging system with the advantages of good image uniformity and good imaging quality. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings involved in the embodiments are briefly introduced. Obviously, the drawings in the following description are only schematic illustrations of some embodiments of the present invention. For those skilled in the art, other forms of drawings can also be constructed based on these drawings without creative work.

[0024] Figure 1 It is a schematic structural diagram of a large aperture zoom objective lens used in an infrared polarization imaging system mentioned in an embodiment of the present invention;

[0025] Figure 2 Based on Figure 1 The modulation transfer function (MTF) curve of the zoom objective lens shown is when the focal length is 12 mm;

[0026] Figure 3 Based on Figure 1 The modulation transfer function (MTF) curve of the zoom objective lens shown is 48mm in focal length;

[0027] Figure 4 Based on Figure 1 The modulation transfer function (MTF) curve of the zoom objective lens shown is when the focal length is 80mm;

[0028] Figure 5 Based on Figure 1 The relative illumination curve of the zoom objective lens shown is when the focal length is 12mm;

[0029] Figure 6 Based on Figure 1 The relative illumination curve of the zoom objective lens shown is when the focal length is 48mm;

[0030] Figure 7 Based on Figure 1 The relative illumination curve of the zoom objective lens shown is when the focal length is 80mm;

[0031] Figure 8 Based on Figure 1 The optical path diagram of the zoom objective lens is shown when the focal length is 12mm, 48mm and 80mm.

[0032] Description of the numbers in the figure:

[0033] G1, 1st zoom group; L11, 1st lens; L12, 2nd lens; L13, 3rd lens;

[0034] G2, the second zoom group; L21, the fourth lens; L22, the fifth lens; L23, the sixth lens;

[0035] G3, the first compensation group; L31, the seventh lens; L32, the eighth lens; L33, the ninth lens; L34, the tenth lens;

[0036] G4, the second compensation group; L41, the 11th lens; L42, the 12th lens; L43, the 13th lens; L44, the 14th lens. DETAILED DESCRIPTION

[0037] The following is a clear and comprehensive description of the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings in the embodiments of the present invention. It should be noted that the embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0038] In order to make the above-mentioned objects, features and advantages of the present invention more clear, the technical solution of the present invention is described in detail below in conjunction with the accompanying drawings and specific implementation methods.

[0039] Embodiment 1:

[0040] like Figure 1 and Figure 8As shown, this example proposes a large aperture zoom objective lens for an infrared polarization imaging system, wherein the first zoom group G1 with positive optical power is arranged in sequence from the object side to the image side along the direction of the optical axis, and is composed of the first lens L11, the second lens L12 and the third lens L13; the second zoom group G2 with negative optical power is composed of the fourth lens L21, the fifth lens L22 and the sixth lens L23; the first compensation group G3 with positive optical power is composed of the seventh lens L31, the eighth lens L32, the ninth lens L33 and the tenth lens L34; the second compensation group G4 with positive optical power is composed of the eleventh lens L41, the twelfth lens L42, the thirteenth lens L43 and the fourteenth lens L44; and the aperture stop is located between the lens L41 and the lens L42. The zoom objective optical system adopts a full-motion compensation method, and the first zoom group G1, the second zoom group G2, the first compensation group G3 and the second compensation group G4 move independently to achieve the purpose of changing the focal length of the optical system and keeping the image plane position unchanged. In the design process, the optical surfaces of all lenses are spherical.

[0041] The focal length of the zoom objective lens ranges from 12mm to 80mm, the corresponding maximum field angle range is 28.1° to 4.3°, the F / # value is 4, the detectable wavelength range is 900nm to 1100nm, and the main wavelength is 1000nm.

[0042] The materials used for the first lens L11, the second lens L12, the third lens L13, the fourth lens L21, the fifth lens L22, the sixth lens L23, the seventh lens L31, the eighth lens L32, the ninth lens L33, the tenth lens L34, the eleventh lens L41, the twelfth lens L42, the thirteenth lens L43, and the fourteenth lens L44 are 724442.464637, 754892.275920, and 6 42057.526629, 639102.568686, 563200.637232, 755201.275795, 664977.519714, 676542.316563, 648228.515702, 638444.540739, 747065.279163, 569291.508986, 740815.281858, 642104.563677.

[0043] Figure 2 , Figure 3 and Figure 4 These are the modulation transfer function (MTF) curves of a large aperture zoom objective lens used in an infrared polarization imaging system when the focal lengths are 12mm, 48mm and 80mm respectively; Figure 5 , Figure 6 and Figure 7 The following are relative illumination curves of a large aperture zoom objective lens used in an infrared polarization imaging system when the focal lengths are 12mm, 48mm, and 80mm, respectively. Figure 2 to Figure 7 It can be seen that the large aperture zoom objective lens for infrared polarization imaging system claimed by the present invention has the characteristics of high imaging quality, various aberrations are corrected to a very good level, and high relative illumination.

[0044] In order to facilitate understanding of the above technical solutions of the present invention, the above technical solutions of the present invention are described in detail below in terms of specific usage.

[0045] In the design of a large aperture zoom objective lens for an infrared polarization imaging system of the present invention, along the direction of the optical axis, it includes a first zoom group G1 with positive optical power, a second zoom group G2 with negative optical power, a first compensation group G3 with positive optical power, and a second compensation group G4 with positive optical power, which are arranged in sequence from the object side to the image side;

[0046] The first zoom group G1 is composed of a first lens L11 with positive power, a second lens L12 with negative power, and a third lens L13 with positive power; the optical surface of the first lens L11 facing the object side is convex toward the object side, and the optical surface facing the image side is convex toward the image side, the optical surface of the second lens L12 facing the object side is convex toward the image side, and the optical surface facing the image side is convex toward the object side, and the optical surface of the third lens L13 facing the object side and the image side are both convex toward the object side; wherein, the first lens L11 and the second lens L12 are doublet lenses;

[0047] The first compensation group G3 is composed of the seventh lens L31 with positive power, the eighth lens L32 with negative power, the ninth lens L33 with negative power, and the tenth lens L34 with positive power; the seventh lens L31 has its optical surface facing the object side convex toward the object side, and its optical surface facing the image side convex toward the image side, the eighth lens L32 has its optical surface facing the object side convex toward the image side, and its optical surface facing the image side convex toward the object side, the ninth lens L33 has its optical surface facing the object side convex toward the object side, and its optical surface facing the image side convex toward the image side, and the tenth lens L34 has its optical surface facing the object side convex toward the object side, and its optical surface facing the image side convex toward the image side. Among them, the eighth lens L32 and the ninth lens L33 are double cemented lenses;

[0048] The second compensation group G4 is composed of an 11th lens L41 with negative optical power, a 12th lens L42 with positive optical power, a 13th lens L43 with negative optical power and a 14th lens L44 with positive optical power; the optical surfaces facing the object side and the image side of the 11th lens L41 are convex toward the image side, the optical surface facing the object side of the 12th lens L42 is convex toward the object side, and the optical surface facing the image side is convex toward the image side, the optical surfaces facing the object side and the image side of the 13th lens L43 are convex toward the object side, and the optical surfaces facing the object side and the image side of the 14th lens L44 are convex toward the object side.

[0049] The aperture stop is located between lens L41 and lens L42.

[0050] The first zoom group G1, the second zoom group G2, the first compensation group G3 and the second compensation group G4 in the zoom objective lens move independently to achieve the purpose of changing the focal length of the optical system and keeping the image plane position unchanged.

[0051] For a large aperture zoom objective lens used in an infrared polarization imaging system, when the focal length of the objective lens is 12 mm, the distance between the first zoom group G1 and the second zoom group G2 is 1 mm, the distance between the second zoom group G2 and the first compensation group G3 is 102.27 mm, and the distance between the first compensation group G3 and the second compensation group is 2.24 mm; when the focal length of the objective lens is 48 mm, the distance between the first zoom group G1 and the second zoom group G2 is 42.6 mm. 9mm, the distance between the second magnification group G2 and the first compensation group G3 is 23.69mm, and the distance between the first compensation group G3 and the second compensation group is 14.92mm; when the focal length of the objective lens is 80mm, the distance between the first magnification group G1 and the second magnification group G2 is 50.24mm, the distance between the second magnification group G2 and the first compensation group G3 is 4.49mm, and the distance between the first compensation group G3 and the second compensation group is 15.66mm.

[0052] The optical structural parameters of a large aperture zoom objective lens for an infrared polarization imaging system proposed in this embodiment are shown in Table 1.

[0053] Table 1 Optical structural parameters of a large aperture zoom objective lens for infrared polarization imaging system with focal lengths of 12 mm, 48 mm, and 80 mm

[0054]

[0055]

[0056] In summary, with the aid of the above technical solution of the invention, the objective lens can achieve better image uniformity, higher imaging quality, compact structure, and easier processing and installation during continuous zooming.

[0057] The remaining technical features in this embodiment can be flexibly selected by those skilled in the art according to actual conditions to meet different specific practical needs. However, it is obvious to those of ordinary skill in the art that it is not necessary to adopt these specific details to implement the present invention. In other examples, in order to avoid confusing the present invention, the composition, structure or components of the formula are not specifically described, and they are all within the technical protection scope defined by the technical solution claimed for protection in the claims of the present invention.

[0058] Modifications and changes made by those skilled in the art that do not depart from the spirit and scope of the present invention should be within the scope of protection of the claims attached to the present invention. In the above description, a large number of specific details are set forth in order to provide a thorough understanding of the present invention. However, it is obvious to those of ordinary skill in the art that these specific details are not necessary to practice the present invention. In other examples, in order to avoid confusing the present invention, well-known technologies, such as specific construction details, operating conditions and other technical conditions, are not specifically described.

[0059] The principles and implementation methods of the present invention are described in this article using specific examples. The description of the above embodiments is only used to help understand the method and core idea of ​​the present invention. At the same time, for those skilled in the art, according to the idea of ​​the present invention, there will be changes in the specific implementation methods and application scope. In summary, the content of this specification should not be understood as limiting the present invention.

Claims

1. A large aperture zoom objective lens for an infrared polarization imaging system, characterized in that: The zoom objective lens comprises a first zoom group (G1) with positive optical power, a second zoom group (G2) with negative optical power, a first compensation group (G3) with positive optical power, and a second compensation group (G4) with positive optical power, which are arranged in sequence from the object side to the image side; The first zoom group (G1) is composed of a first lens (L11) with positive focal power, a second lens (L12) with negative focal power, and a third lens (L13) with positive focal power; The second zoom group (G2) is composed of a fourth lens (L21) with negative optical power, a fifth lens (L22) with negative optical power, and a sixth lens (L23) with positive optical power; The first compensation group (G3) is composed of a seventh lens (L31) with positive focal power, an eighth lens (L32) with negative focal power, a ninth lens (L33) with negative focal power, and a tenth lens (L34) with positive focal power; The second compensation group (G4) consists of an 11th lens (L41) with negative optical focal power, a 12th lens (L42) with positive optical focal power, a 13th lens (L43) with negative optical focal power and a 14th lens (L44) with positive optical focal power.

2. The large aperture zoom objective lens for an infrared polarization imaging system according to claim 1, characterized in that: The optical surface of the first lens (L11) facing the object side is convex toward the object side, and the optical surface facing the image side is convex toward the image side; the optical surface of the second lens (L12) facing the object side is convex toward the image side, and the optical surface facing the image side is convex toward the object side; the optical surfaces of the third lens (L13) facing both the object side and the image side are convex toward the object side; wherein the first lens (L11) and the second lens (L12) are double-cemented lenses.

3. The large aperture zoom objective lens for an infrared polarization imaging system according to claim 1, characterized in that: The optical surfaces of the fourth lens (L21) facing the object side and the image side are both convex toward the object side; the optical surface of the fifth lens (L22) facing the object side is convex toward the image side, and the optical surface facing the image side is convex toward the object side; the optical surfaces of the sixth lens (L23) facing the object side and the image side are both convex toward the object side; wherein the fifth lens (L22) and the sixth lens (L23) are double-cemented lenses.

4. The large aperture zoom objective lens for an infrared polarization imaging system according to claim 1, characterized in that: The optical surface of the seventh lens (L31) facing the object side is convex toward the object side, and the optical surface of the seventh lens (L31) facing the image side is convex toward the image side; the optical surface of the eighth lens (L32) facing the object side is convex toward the image side, and the optical surface of the eighth lens (L32) facing the image side is convex toward the object side; the optical surface of the ninth lens (L33) facing the object side is convex toward the object side, and the optical surface of the ninth lens (L33) facing the image side is convex toward the image side; the optical surface of the tenth lens (L34) facing the object side is convex toward the object side, and the optical surface of the tenth lens (L34) facing the object side is convex toward the object side, and the optical surface of the tenth lens (L34) facing the image side is convex toward the image side; wherein the eighth lens (L32) and the ninth lens (L33) are double-cemented lenses.

5. The large aperture zoom objective lens for an infrared polarization imaging system according to claim 1, characterized in that: The optical surfaces of the 11th lens (L41) facing the object side and the image side are both convex toward the image side; the optical surface of the 12th lens (L42) facing the object side is convex toward the object side, and the optical surface facing the image side is convex toward the image side; the optical surfaces of the 13th lens (L43) facing the object side and the image side are both convex toward the object side; and the optical surfaces of the 14th lens (L44) facing the object side and the image side are both convex toward the object side.

6. The large aperture zoom objective lens for an infrared polarization imaging system according to claim 5, characterized in that: An aperture stop is provided between the 12th lens (L42) and the 13th lens (L43).

7. The large aperture zoom objective lens for an infrared polarization imaging system according to claim 1, characterized in that: The optical surfaces of all lenses in the zoom objective lens are spherical in design; the first zoom group (G1), the second zoom group (G2), the first compensation group (G3) and the second compensation group (G4) move independently to achieve the purpose of changing the focal length of the optical system and keeping the image plane position unchanged.

8. The large aperture zoom objective lens for an infrared polarization imaging system according to claim 1, characterized in that: The focal length of the zoom objective lens varies in the range of 12 mm to 80 mm, the corresponding maximum field angle range is 28.1° to 4.3°, the F / # value is 4, the detected wavelength range is 900 nm to 1100 nm, and the main wavelength is 1000 nm.

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