A long focal length, large aperture, mid-wave cooled infrared lens and imaging device

Abstract

This application discloses a long-focal-length, large-aperture, mid-wave cooled infrared lens, comprising a first lens, a second lens, a third lens, a fourth lens, a fifth lens, a sixth lens, a seventh lens, and an eighth lens arranged sequentially along the optical axis transmission direction. The first and third lenses are both meniscus positive lenses with their convex surfaces facing the object side; the second, fourth, and fifth lenses are all meniscus negative lenses with their convex surfaces facing the object side; the sixth and eighth lenses are both biconvex lenses; and the seventh lens is a meniscus negative lens with its convex surface facing the image side. The lens provided by this application has a simple structure, a large target area, and clear imaging, and can be used with a 640×512 resolution, 15μm cooled detector. This application also discloses an imaging device.

Description

Technical Field

[0001] This application belongs to the field of infrared optical equipment technology, specifically relating to a long focal length, large aperture, mid-wave cooled infrared lens and imaging device. Background Technology

[0002] Mid-wave cooled infrared thermal imaging core is an advanced device that operates based on the principle of infrared radiation. It is the core component of a cooled infrared thermal imager. The core employs cooling technology, which significantly reduces detector thermal noise and improves detection sensitivity and image quality. Mid-wave cooled infrared thermal imaging cores feature high sensitivity, long-range detection, clear image details, modular design, and intelligent image processing, and are widely used in military and defense, industrial monitoring, and medical diagnostics. To improve long-range detection accuracy, a long focal length lens is required. Summary of the Invention

[0003] Based on this, this application provides a long focal length, large aperture, mid-wave cooled infrared lens and imaging device.

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

[0005] A long focal length, large aperture, mid-wave cooled infrared lens includes a first lens, a second lens, a third lens, a fourth lens, a fifth lens, a sixth lens, a seventh lens, and an eighth lens arranged sequentially along the optical axis transmission direction; the first lens and the third lens are both meniscus positive lenses with their convex surfaces facing the object side, the second lens, the fourth lens, and the fifth lens are all meniscus negative lenses with their convex surfaces facing the object side, the sixth lens and the eighth lens are both biconvex lenses, and the seventh lens is a meniscus negative lens with its convex surface facing the image side;

[0006] The air gap between the first lens and the second lens is 55.917 mm, the air gap between the second lens and the third lens is 8.491 mm, the air gap between the third lens and the fourth lens is 143.845 mm, the air gap between the fourth lens and the fifth lens is 43.299 mm, the air gap between the fifth lens and the sixth lens is 89.976 mm, the air gap between the sixth lens and the seventh lens is 10.514 mm, and the air gap between the seventh lens and the eighth lens is 3.327 mm.

[0007] Further, the first lens has a center thickness of 22 mm, an object-side radius of curvature of 255.26 mm, and an image-side radius of curvature of 495.716 mm; the second lens has a center thickness of 8.5 mm, an object-side radius of curvature of 866.535 mm, and an image-side radius of curvature of 315.04 mm; the third lens has a center thickness of 11.5 mm, an object-side radius of curvature of 322.545 mm, and an image-side radius of curvature of 626.092 mm; and the fourth lens has a center thickness of 4 mm, an object-side radius of curvature of 68.319 mm, and an image-side radius of curvature of 47.546 mm. The fifth lens has a center thickness of 5 mm, an object-side radius of curvature of 17.496 mm, and an image-side radius of curvature of 14.102 mm. The sixth lens has a center thickness of 7.5 mm, an object-side radius of curvature of 185.744 mm, and an image-side radius of curvature of -450.442 mm. The seventh lens has a center thickness of 4 mm, an object-side radius of curvature of -67.692 mm, and an image-side radius of curvature of -437.05 mm. The eighth lens has a center thickness of 12.5 mm, an object-side radius of curvature of 352.081 mm, and an image-side radius of curvature of -67.924 mm.

[0008] 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.

[0009] 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.

[0010] Furthermore, the applicable spectral range of the lens is 3.7~4.8μm, the focal length of the lens is 460mm, and the F number is 2.

[0011] Furthermore, the lens adopts a long back focal length design.

[0012] An imaging device includes a long focal length, large aperture, mid-wave cooled infrared lens as described above, and a detector that receives the image captured by the lens.

[0013] Furthermore, the detector has 640×512 pixels and a pixel size of 15μm.

[0014] Furthermore, the detector includes a first window, a second window, a filter, and a detector focal plane array arranged sequentially.

[0015] Furthermore, the detector also includes an aperture stop, which is disposed between the filter and the detector focal plane array.

[0016] The lens provided in this application has a simple structure, a large target surface, clear imaging, and can be used with a cooled detector with a resolution of 640×512 and 15μm. Attached Figure Description

[0017] 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.

[0018] Figure 1 This is a schematic diagram of the structure of an imaging device provided in an embodiment of this application;

[0019] Figure 2 for Figure 1 A schematic diagram of the detector structure in the imaging device is shown.

[0020] Figure 3 MTF diagram of a long focal length, large aperture, mid-wave cooled infrared lens provided in an embodiment of this application;

[0021] Figure 4 A dot diagram of a long focal length, large aperture, mid-wave cooled infrared lens provided in an embodiment of this application.

[0022] Label Explanation:

[0023] 11. First lens; 12. Second lens; 13. Third lens; 14. Fourth lens; 15. Fifth lens; 16. Sixth lens; 17. Seventh lens; 18. Eighth lens; 20. Detector; 21. First window; 22. Second window; 23. Filter; 24. Aperture; 25. Detector focal plane array. Detailed Implementation

[0024] 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.

[0025] One embodiment of this application provides an imaging device, which includes a long focal length, large aperture, mid-wave cooled infrared lens and a detector for receiving the image captured by the lens. The lens has a focal length of 460mm, an applicable spectral range of 3.7~4.8μm, and an F-number of 2. The detector is a cooled detector with a pixel count of 640×512 and a pixel size of 15μm.

[0026] Please see Figure 1The lens includes a first lens 11, a second lens 12, a third lens 13, a fourth lens 14, a fifth lens 15, a sixth lens 16, a seventh lens 17, and an eighth lens 18 arranged sequentially along the optical axis transmission direction. The first lens 11 and the third lens 13 are both meniscus positive lenses with their convex surfaces facing the object side; the second lens 12, the fourth lens 14, and the fifth lens 15 are all meniscus negative lenses with their convex surfaces facing the object side; the sixth lens 16 and the eighth lens 18 are both biconvex lenses; and the seventh lens 17 is a meniscus negative lens with its convex surface facing the image side.

[0027] like Figure 2 As shown, the detector 20 further includes a first window 21, a second window 22, a filter 23, and a detector focal plane array 25 arranged sequentially, so as to... Figure 1 and Figure 2 For example, the light beam passes through multiple lenses from left to right and then forms an image on the detector focal plane array 25 through the first window 21, the second window 22, and the filter 23.

[0028] In one embodiment, the detector 20 further includes an aperture 24 disposed between the filter 23 and the detector focal plane array 25.

[0029] In one embodiment, the lens employs a long back focal length design.

[0030] As shown in Table 1, as an example, the air gap between the first lens 11 and the second lens 12 is 55.917 mm, the air gap between the second lens 12 and the third lens 13 is 8.491 mm, the air gap between the third lens 13 and the fourth lens 14 is 143.845 mm, the air gap between the fourth lens 14 and the fifth lens 15 is 43.299 mm, the air gap between the fifth lens 15 and the sixth lens 16 is 89.976 mm, the air gap between the sixth lens 16 and the seventh lens 17 is 10.514 mm, and the air gap between the seventh lens 17 and the eighth lens 18 is 3.327 mm; the air gap between the eighth lens 18 and the first window 21 is 14 mm, the air gap between the first window 21 and the second window 22 is 6 mm, the air gap between the second window 22 and the filter 23 is 2.6 mm, the air gap between the filter 23 and the aperture 24 is 0.26 mm, and the air gap between the aperture 24 and the detector focal plane array 25 is 20.47 mm. It is understandable that the air gap mentioned above refers to the air gap along the optical axis.

[0031] Furthermore, the first lens 11 has a center thickness of 22 mm, an object-side radius of curvature of 255.26 mm, and an image-side radius of curvature of 495.716 mm; the second lens 12 has a center thickness of 8.5 mm, an object-side radius of curvature of 866.535 mm, and an image-side radius of curvature of 315.04 mm; the third lens 13 has a center thickness of 11.5 mm, an object-side radius of curvature of 322.545 mm, and an image-side radius of curvature of 626.092 mm; and the fourth lens 14 has a center thickness of 4 mm, an object-side radius of curvature of 68.319 mm, and an image-side radius of curvature of 47.546 mm. The fifth lens 15 has a center thickness of 5mm, an object-side radius of curvature of 17.496mm, and an image-side radius of curvature of 14.102mm; the sixth lens 16 has a center thickness of 7.5mm, an object-side radius of curvature of 185.744mm, and an image-side radius of curvature of -450.442mm; the seventh lens 17 has a center thickness of 4mm, an object-side radius of curvature of -67.692mm, and an image-side radius of curvature of -437.05mm; the eighth lens 18 has a center thickness of 12.5mm, an object-side radius of curvature of 352.081mm, and an image-side radius of curvature of -67.924mm.

[0032] 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 11 is the object side surface, and the S2 surface is the image side surface. Other components are similar and will not be described in detail here.

[0033] In one embodiment, the first lens 11, the fifth lens 15, and the lens satisfy the following conditions:

[0034] 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 11, and f5 is the effective focal length of the fifth lens 15.

[0035] Table 1 Component Parameters

[0036]

[0037] It should be noted, in conjunction with Table 1, that all the lenses mentioned above are made using domestically produced optical materials.

[0038] As shown in Table 1, the image-side surfaces of the fourth lens 14, the fifth lens 15, and the eighth lens 18, as well as the object-side surface of the seventh lens 17, are aspherical surfaces; all other surfaces are spherical. All aspherical surfaces satisfy the aspherical formula:

[0039]

[0040] 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.

[0041] Table 2 Aspherical Data

[0042]

[0043] Figure 3 and Figure 4 The images show the MTF and dot plot of a long-focal-length, large-aperture mid-wave cooled infrared lens. In the MTF chart, the horizontal axis represents different spatial frequencies, and the vertical axis represents modulation. The diagrams show that the lens corrects various aberrations across different wavelengths, ensuring sufficient resolution at both the center and periphery.

[0044] In summary, the long focal length, large aperture, mid-wave cooled infrared lens provided in this application operates in the 3.7~4.8μm band; has a focal length of f=460mm; and an F-number of 2. The lens provided in this application has a simple structure, a large target surface, and clear imaging, and can be used with a 640×512 resolution, 15μm cooled detector 20.

[0045] 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 long focal length, large aperture, mid-wave cooled infrared lens, characterized in that, It consists of a first lens, a second lens, a third lens, a fourth lens, a fifth lens, a sixth lens, a seventh lens, and an eighth lens arranged sequentially along the optical axis transmission direction; the first lens and the third lens are both meniscus positive lenses with their convex surfaces facing the object side, the second lens, the fourth lens, and the fifth lens are all meniscus negative lenses with their convex surfaces facing the object side, the sixth lens and the eighth lens are both biconvex lenses, and the seventh lens is a meniscus negative lens with its convex surface facing the image side; The air gap between the first lens and the second lens is 55.917 mm, the air gap between the second lens and the third lens is 8.491 mm, the air gap between the third lens and the fourth lens is 143.845 mm, the air gap between the fourth lens and the fifth lens is 43.299 mm, the air gap between the fifth lens and the sixth lens is 89.976 mm, the air gap between the sixth lens and the seventh lens is 10.514 mm, and the air gap between the seventh lens and the eighth lens is 3.327 mm.

2. The long focal length, large aperture, mid-wave cooled infrared lens according to claim 1, characterized in that, The first lens has a center thickness of 22 mm, an object-side radius of curvature of 255.26 mm, and an image-side radius of curvature of 495.716 mm; the second lens has a center thickness of 8.5 mm, an object-side radius of curvature of 866.535 mm, and an image-side radius of curvature of 315.04 mm; the third lens has a center thickness of 11.5 mm, an object-side radius of curvature of 322.545 mm, and an image-side radius of curvature of 626.092 mm; the fourth lens has a center thickness of 4 mm, an object-side radius of curvature of 68.319 mm, and an image-side radius of curvature of 47.546 mm. The fifth lens has a center thickness of 5 mm, an object-side radius of curvature of 17.496 mm, and an image-side radius of curvature of 14.102 mm; the sixth lens has a center thickness of 7.5 mm, an object-side radius of curvature of 185.744 mm, and an image-side radius of curvature of -450.442 mm; the seventh lens has a center thickness of 4 mm, an object-side radius of curvature of -67.692 mm, and an image-side radius of curvature of -437.05 mm; and the eighth lens has a center thickness of 12.5 mm, an object-side radius of curvature of 352.081 mm, and an image-side radius of curvature of -67.924 mm.

3. The long focal length, large aperture, mid-wave cooled 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 long focal length, large aperture, mid-wave cooled 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 long focal length, large aperture, mid-wave cooled infrared lens according to claim 1, characterized in that, The applicable spectral range of the lens is 3.7~4.8μm, the focal length of the lens is 460mm, and the F number is 2.

6. The long focal length, large aperture, mid-wave cooled infrared lens according to claim 1, characterized in that, The lens features a long back focal length design.

7. An imaging device, characterized in that, It includes the long focal length, large aperture, mid-wave cooled infrared lens as described in any one of claims 1-6, and the detector that receives the image from the lens.

8. The imaging apparatus according to claim 7, characterized in that, The detector has 640×512 pixels and a pixel size of 15μm.

9. The imaging apparatus according to claim 7, characterized in that, The detector includes a first window, a second window, a filter, and a detector focal plane array arranged sequentially.

10. The imaging apparatus according to claim 9, characterized in that, The detector also includes an aperture stop, which is disposed between the filter and the detector focal plane array.

Images