A medium-long wave dual-color composite infrared lens

Abstract

The application discloses a middle-long wave dual-color composite infrared lens, the applicable spectral range of the lens is 3-5 mu m and 8-12 mu m, the lens comprises a first lens, a second lens, a third lens, a fourth lens and a fifth lens which are sequentially arranged along the transmission direction of the optical axis, the first lens and the fourth lens are both meniscus positive lenses with the convex surface facing the object side, the second lens is a flat-concave negative lens, and the third lens and the fifth lens are both meniscus negative lenses with the convex surface facing the object side. The lens structure provided by the application is simple, the target surface is large, the imaging is clear, and the lens can be applied to the middle-long wave spectral range, so the application range is relatively large.

Description

Technical Field

[0001] This application belongs to the field of infrared optical equipment technology, specifically relating to a mid-to-long-wave dual-color composite infrared lens. Background Technology

[0002] With the development of science and technology, infrared imaging technology has been widely used in national defense, industry, medicine, power detection, and other fields, showing broad application prospects and practical value. Infrared detection can be performed without contact with the target, which can be a high-temperature object or an object with a very low temperature; infrared instruments can detect very small temperature differences on the surface of an object. Based on abnormal temperatures on the object's surface, abnormal points can be detected, facilitating troubleshooting. However, existing short-range detection instruments typically use long-wavelength detection, limiting their applicability. Summary of the Invention

[0003] Based on this, this application provides a medium-to-long-wave dual-color composite infrared lens with a wide range of applications.

[0004] The technical solution proposed in this application is as follows:

[0005] A mid-to-long-wave dual-color composite infrared lens, the applicable spectral range of the lens is 3~5μm and 8~12μm, the lens includes a first lens, a second lens, a third lens, a fourth lens and a fifth lens arranged sequentially along the optical axis transmission direction; the first lens and the fourth lens are both meniscus positive lenses with the convex surface facing the object side, the second lens is a plano-concave negative lens, and the third lens and the fifth lens are both meniscus negative lenses with the convex surface facing the object side.

[0006] Furthermore, the air gap between the object plane and the first lens is 720 mm, the air gap between the first lens and the second lens is 5.488 mm, the air gap between the second lens and the third lens is 6.607 mm, the air gap between the third lens and the fourth lens is 177.889 mm, the air gap between the fourth lens and the fifth lens is 6.416 mm, and the air gap between the fifth lens and the image plane is 25 mm.

[0007] Further, the first lens has a center thickness of 32.6 mm, an object-side radius of curvature of 163.732 mm, and an image-side radius of curvature of 7304.96 mm; the second lens has a center thickness of 15 mm, an object-side surface that is flat, and an image-side radius of curvature of 1201.752 mm; the third lens has a center thickness of 15 mm, an object-side radius of curvature of 3294.154 mm, and an image-side radius of curvature of 185.775 mm; the fourth lens has a center thickness of 21 mm, an object-side radius of curvature of 71.381 mm, and an image-side radius of curvature of 190 mm; and the fifth lens has a center thickness of 20 mm, an object-side radius of curvature of 90 mm, and an image-side radius of curvature of 47.953 mm.

[0008] Furthermore, it also includes an aperture stop, which is disposed between the object surface and the first lens.

[0009] Furthermore, the first lens and the lens satisfy the following condition: 0 < f1 / f < 1, where f1 is the effective focal length of the first lens and f is the effective focal length of the lens.

[0010] Furthermore, the fifth lens and the lens satisfy the following condition: 0 < f5 / f < 1, where f5 is the effective focal length of the fifth lens and f is the effective focal length of the lens.

[0011] Furthermore, the lens has a focal length of 170mm and a field of view of 8°.

[0012] Furthermore, the entrance pupil diameter of the lens is 70mm.

[0013] Furthermore, the first lens is made of CVD zinc selenide, the second and fifth lenses are both made of germanium single crystal, the third lens is made of CVD zinc sulfide, and the fourth lens is made of chalcogenide glass.

[0014] The lens provided in this application has a simple structure, a large target surface, clear imaging, and is applicable to the medium and long wavelength spectral range, making it suitable for a wide range of applications. Attached Figure Description

[0015] The accompanying drawings are provided to further understand this application and form part of the specification. They are used together with the embodiments of this application to explain this application and do not constitute a limitation thereof.

[0016] Figure 1 A schematic diagram of the structure of a mid-to-long-wave dual-color composite infrared lens provided in an embodiment of this application;

[0017] Figure 2 MTF diagram of a mid-to-long wavelength dual-color composite infrared lens provided in an embodiment of this application at wavelengths of 3~5μm;

[0018] Figure 3 A dot plot of a mid-to-long-wave dual-color composite infrared lens provided in an embodiment of this application at wavelengths of 3~5μm;

[0019] Figure 4 MTF diagram of a mid-to-long wavelength dual-color composite infrared lens provided in an embodiment of this application at wavelengths of 8~12μm;

[0020] Figure 5 A dot plot of a medium-long wavelength dual-color composite infrared lens provided in an embodiment of this application at wavelengths of 8~12μm.

[0021] Label Explanation:

[0022] 11. Object plane; 12. First lens; 13. Second lens; 14. Third lens; 15. Fourth lens; 16. Fifth lens; 17. Image plane. Detailed Implementation

[0023] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of this application.

[0024] One embodiment of this application provides a mid-to-long-wave dual-color composite infrared lens. The lens has a focal length of 170mm, an applicable spectral range of 3~5μm and 8~12μm, and a field of view of 8°. It also features a large aperture design with an entrance pupil diameter of 70mm.

[0025] Please see Figure 1 The lens includes a first lens 12, a second lens 13, a third lens 14, a fourth lens 15, and a fifth lens 16 arranged sequentially along the optical axis transmission direction. The first lens 12 and the fourth lens 15 are both meniscus positive lenses with their convex surfaces facing the object side, the second lens 13 is a plano-concave negative lens, and the third lens 14 and the fifth lens 16 are both meniscus negative lenses with their convex surfaces facing the object side.

[0026] As shown in Table 1, as an example, the air gap between the object plane 11 and the first lens 12 is 720 mm, the air gap between the first lens 12 and the second lens 13 is 5.488 mm, the air gap between the second lens 13 and the third lens 14 is 6.607 mm, the air gap between the third lens 14 and the fourth lens 15 is 177.889 mm, the air gap between the fourth lens 15 and the fifth lens 16 is 6.416 mm, and the air gap between the fifth lens 16 and the image plane 17 is 25 mm. It should be understood that the above air gaps refer to the air gaps along the optical axis.

[0027] Furthermore, the first lens 12 has a center thickness of 32.6 mm, an object-side radius of curvature of 163.732 mm, and an image-side radius of curvature of 7304.96 mm; the second lens 13 has a center thickness of 15 mm, an object-side surface that is flat, and an image-side radius of curvature of 1201.752 mm; the third lens 14 has a center thickness of 15 mm, an object-side radius of curvature of 3294.154 mm, and an image-side radius of curvature of 185.775 mm; the fourth lens 15 has a center thickness of 21 mm, an object-side radius of curvature of 71.381 mm, and an image-side radius of curvature of 190 mm; and the fifth lens 16 has a center thickness of 20 mm, an object-side radius of curvature of 90 mm, and an image-side radius of curvature of 47.953 mm.

[0028] Understandably, in Figure 1 In the illustrated embodiment, the optical axis transmission direction is from left to right, with the left side of the lens being the object side and the right side being the image side. For example, the S1 surface of the first lens 12 is the object side surface, and the S2 surface is the image side surface. Other lenses are not described in detail.

[0029] In one embodiment, the lens further includes an aperture stop disposed between the object plane 11 and the first lens 12.

[0030] In one embodiment, the first lens 12, the fifth lens 16, and the lens satisfy the following conditions:

[0031] 0 < f1 / f < 1, 0 < f5 / f < 1; where f is the effective focal length of the lens, f1 is the effective focal length of the first lens 12, and f5 is the effective focal length of the fifth lens 16.

[0032] Table 1 Component Parameters

[0033]

[0034] As shown in Table 1, the first lens 12 is made of CVD (Chemical Vapor Deposition) zinc selenide, the second lens 13 and the fifth lens 16 are both made of germanium single crystal, the third lens 14 is made of CVD zinc sulfide, and the fourth lens 15 is made of chalcogenide glass. It should be noted that all the lenses mentioned above are made using domestically produced optical materials. In one specific embodiment, the fourth lens 15 is made of IRG207 material.

[0035] Based on Table 1, it can be further determined that the image-side surfaces of the third lens 14, the fourth lens 15, and the fifth lens 16 are all aspherical, and all aspherical surfaces satisfy the aspherical formula:

[0036]

[0037] Where z represents the distance of the surface from the vertex of the surface along the optical axis, c represents the curvature of the vertex of the surface, K represents the quadratic surface coefficient, h represents the distance from the optical axis to the surface, and B, C, D, E, and F represent the fourth, sixth, eighth, tenth, and twelfth order surface coefficients, respectively. Meanwhile, the aspherical data for each lens are shown in Table 2.

[0038] Table 2 Aspherical Data

[0039]

[0040] Figure 2 and Figure 3 The MTF and dot plots of the mid-to-long-wave dual-color composite infrared lens are shown respectively, at wavelengths of 3~5μm. Figure 4 and Figure 5 The images show the MTF (Medium-Frequency Formulation) and dot plot of the mid-to-long-wave dual-color composite infrared lens at wavelengths of 8–12 μm. In the MTF chart, the horizontal axis represents different spatial frequencies, and the vertical axis represents modulation depth. As can be seen from the drawings, this lens corrects various aberrations across different wavelengths, ensuring sufficient resolution in both the center and peripheral fields of view.

[0041] In summary, the operating wavelengths of the mid-to-long-wave dual-color composite infrared lens provided in this application are 3~5μm and 8~12μm; the focal length is f=170mm and the field of view is 8°. The lens provided in this application has a simple structure, a large target surface, clear imaging, and is applicable to the mid-to-long-wave spectrum, thus having a wide range of applications.

[0042] Although embodiments of this application have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and variations can be made to these embodiments without departing from the principles and spirit of this application, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A mid-to-long-wave dual-color composite infrared lens, characterized in that, The applicable spectral range of the lens is 3~5μm and 8~12μm, and the focal length is 170mm. The lens is composed of a first lens, a second lens, a third lens, a fourth lens and a fifth lens arranged sequentially along the optical axis transmission direction. The first lens and the fourth lens are both meniscus positive lenses with their convex surfaces facing the object side, the second lens is a plano-concave negative lens, and the third lens and the fifth lens are both meniscus negative lenses with their convex surfaces facing the object side. The air gap between the object plane and the first lens is 720 mm. The center thickness of the first lens is 32.6 mm, the radius of curvature of the object side is 163.732 mm, and the radius of curvature of the image side is 7304.96 mm. The center thickness of the second lens is 15 mm, the object side is flat, and the radius of curvature of the image side is 1201.752 mm. The center thickness of the third lens is 15 mm, the radius of curvature of the object side is 3294.154 mm, and the radius of curvature of the image side is 185.775 mm. The center thickness of the fourth lens is 21 mm, the radius of curvature of the object side is 71.381 mm, and the radius of curvature of the image side is 190 mm. The center thickness of the fifth lens is 20 mm, the radius of curvature of the object side is 90 mm, and the radius of curvature of the image side is 47.953 mm. The image-side surfaces of the third lens, the fourth lens, and the fifth lens are all aspherical. The air gap between the first lens and the second lens is 5.488 mm, the air gap between the second lens and the third lens is 6.607 mm, the air gap between the third lens and the fourth lens is 177.889 mm, the air gap between the fourth lens and the fifth lens is 6.416 mm, and the air gap between the fifth lens and the image plane is 25 mm. The first lens is made of CVD zinc selenide, the second and fifth lenses are both made of germanium single crystal, the third lens is made of CVD zinc sulfide, and the fourth lens is made of chalcogenide glass.

2. The mid-to-long-wave dual-color composite infrared lens according to claim 1, characterized in that, It also includes an aperture stop, which is disposed between the object surface and the first lens.

3. The mid-to-long-wave dual-color composite infrared lens according to claim 1, characterized in that, The first lens and the lens satisfy the following condition: 0 < f1 / f < 1, where f1 is the effective focal length of the first lens and f is the effective focal length of the lens.

4. The mid-to-long-wave dual-color composite infrared lens according to claim 1, characterized in that, The fifth lens and the lens satisfy the following condition: 0 < f5 / f < 1, where f5 is the effective focal length of the fifth lens and f is the effective focal length of the lens.

5. The mid-to-long-wave dual-color composite infrared lens according to claim 1, characterized in that, The field of view is 8°.

6. The mid-to-long-wave dual-color composite infrared lens according to claim 1, characterized in that, The entrance pupil diameter of the lens is 70mm.

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