Two-color composite uncooled athermalization infrared lens and imaging device

Abstract

The invention provides a double-color composite uncooled athermalization infrared lens, the applicable spectral ranges are 3-5 [mu] m and 8-12 [mu] m, and the lens comprises a first lens, a second lens, a third lens, a fourth lens and a fifth lens which are sequentially arranged in the optical axis transmission direction; the first lens and the fourth lens are meniscus positive lenses with convex surfaces facing the object side; the second lens, the third lens and the fifth lens are meniscus negative lenses with convex surfaces facing the object side; the air gap between the first lens and the second lens is 0.5 mm, the air gap between the second lens and the third lens is 18.2 mm, the air gap between the third lens and the fourth lens is 31.89 mm, and the air gap between the fourth lens and the fifth lens is 0.5 mm. The lens provided by the invention is simple in structure, large in target surface and clear in imaging, is adaptive to a double-color movement, and can be matched with an uncooled detector with the resolution of 1280 * 1024 and 12 [mu] m for use. The invention further discloses an imaging device.

Description

Technical Field

[0001] The present application belongs to the field of infrared optical equipment technology, and specifically relates to a two-color composite non-cooled athermal infrared lens and an imaging device. Background Art

[0002] With the rapid development of science and technology, the emergence of uncooled infrared movement with two colors of medium wave 3~5μm and long wave 8~14μm has become inevitable. Two-color infrared thermal imagers with this movement are widely used in many fields such as industry, meteorology, autonomous driving and aerospace, but infrared lenses with two-color movement are relatively rare in the market. Summary of the invention

[0003] Based on this, the present application provides a two-color composite uncooled athermal infrared lens and an imaging device.

[0004] The technical solution proposed in this application is: A two-color composite uncooled athermal infrared lens, applicable to the spectral range of 3-5 μm and 8-12 μm, the lens comprises a first lens, a second lens, a third lens, a fourth lens and a fifth lens arranged in sequence along the transmission direction of the optical axis; the first lens and the fourth lens are both positive meniscus lenses with convex surfaces facing the object side, the second lens, the third lens and the fifth lens are all negative meniscus lenses with convex surfaces facing the object side; the air gap between the first lens and the second lens is 0.5 mm, the air gap between the second lens and the third lens is 18.2 mm, the air gap between the third lens and the fourth lens is 31.89 mm, and the air gap between the fourth lens and the fifth lens is 0.5 mm.

[0005] Further, the center thickness of the first lens is 16.5mm, the radius of curvature of the object side is 60.78mm, and the radius of curvature of the image side is 239.376mm; the center thickness of the second lens is 4mm, the radius of curvature of the object side is 111.71mm, and the radius of curvature of the image side is 78.161; the center thickness of the third lens is 3.2mm, the radius of curvature of the object side is 123.785mm, and the radius of curvature of the image side is 50.86mm; the center thickness of the fourth lens is 13mm, the radius of curvature of the object side is 37.662mm, and the radius of curvature of the image side is 168.539mm; the center thickness of the fifth lens is 4.8mm, the radius of curvature of the object side is 34.728mm, and the radius of curvature of the image side is 24.363mm.

[0006] Furthermore, it also includes an aperture, which is arranged between the first lens and the second lens.

[0007] Furthermore, the first lens and the lens meet the following condition: f1 / f<1, wherein f1 is the effective focal length of the first lens, and f is the effective focal length of the lens.

[0008] Furthermore, the fifth lens and the lens satisfy the following condition: 1<f5 / f<2, wherein f5 is the effective focal length of the fifth lens, and f is the effective focal length of the lens.

[0009] Furthermore, the focal length of the lens is 75 mm and the F number is 0.9.

[0010] Furthermore, the lens adopts an optical athermal design.

[0011] An imaging device comprises the above-mentioned two-color composite uncooled athermal infrared lens and a detector for receiving the image formed by the lens.

[0012] Furthermore, the number of pixels of the detector is 1280×1024, and the pixel size is 12 μm.

[0013] The lens provided in this application has a simple structure, a large target surface, and clear imaging, is suitable for a two-color movement, and can be matched with a resolution of 1280×1024, 12μm uncooled detector. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] The accompanying drawings are used to provide further understanding of the present application and constitute a part of the specification. They are used to explain the present application together with the embodiments of the present application and do not constitute a limitation of the present application.

[0015] Figure 1 A schematic diagram of the structure of an imaging device provided in one embodiment of the present application; Figure 2 This is an MTF diagram of a two-color composite uncooled athermal infrared lens provided in an embodiment of the present application at a wavelength of 3-5 μm; Figure 3 This is a spot diagram of a two-color composite uncooled athermal infrared lens provided in an embodiment of the present application at a wavelength of 3-5 μm; Figure 4 This is the MTF diagram of the two-color composite uncooled athermal infrared lens provided in one embodiment of the present application at a wavelength of 8-12 μm; Figure 5 This is a spot diagram of a two-color composite uncooled athermal infrared lens provided in an embodiment of the present application at a wavelength of 8-12 μm.

[0016] Description of labels: 11. First lens; 12. Second lens; 13. Third lens; 14. Fourth lens; 15. Fifth lens; 21. Protection window; 22. Detector focal plane array. DETAILED DESCRIPTION

[0017] The following will be combined with the drawings in the embodiments of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0018] An embodiment of the present application provides an imaging device, which includes a two-color composite uncooled athermal infrared lens and a detector for receiving the image formed by the lens. The focal length of the lens is 75 mm, the applicable spectral range is: 3~5μm and 8~12μm, and the F number is 0.9. The detector is an uncooled detector, and the number of pixels of the detector is 1280×1024, and the pixel size is 12μm.

[0019] See also Figure 1 The lens comprises a first lens 11, a second lens 12, a third lens 13, a fourth lens 14 and a fifth lens 15 arranged in sequence along the optical axis transmission direction. The first lens 11 and the fourth lens 14 are positive meniscus lenses with convex surfaces facing the object side, and the second lens 12, the third lens 13 and the fifth lens 15 are negative meniscus lenses with convex surfaces facing the object side. Further, the detector comprises a protective window 21 and a detector focal plane array 22 arranged in sequence, so as to Figure 1 For example, after the light beam passes through the first lens 11 , the second lens 12 , the third lens 13 , the fourth lens 14 and the fifth lens 15 from left to right, it forms an image on the detector focal plane array 22 through the protection window 21 .

[0020] In one embodiment, the lens further includes an aperture, which is disposed between the first lens 11 and the second lens 12. Furthermore, the lens adopts an optical athermal design.

[0021] As shown in Table 1, as an example, the air gap between the first lens 11 and the second lens 12 is 0.5 mm, the air gap between the second lens 12 and the third lens 13 is 18.2 mm, the air gap between the third lens 13 and the fourth lens 14 is 31.89 mm, the air gap between the fourth lens 14 and the fifth lens 15 is 0.5 mm; the air gap between the fifth lens 15 and the protective window 21 is 17.472 mm, and the air gap between the protective window 21 and the detector focal plane array 22 is 1 mm. It can be understood that the above-mentioned air gaps are air gaps on the optical axis.

[0022] Further, the center thickness of the first lens 11 is 16.5 mm, the radius of curvature of the object side is 60.78 mm, and the radius of curvature of the image side is 239.376 mm; the center thickness of the second lens 12 is 4 mm, the radius of curvature of the object side is 111.71 mm, and the radius of curvature of the image side is 78.161; the center thickness of the third lens 13 is 3.2 mm, the radius of curvature of the object side is 123.785 mm, and the radius of curvature of the image side is 50.86 mm; the center thickness of the fourth lens 14 is 13 mm, the radius of curvature of the object side is 37.662 mm, and the radius of curvature of the image side is 168.539 mm; the center thickness of the fifth lens 15 is 4.8 mm, the radius of curvature of the object side is 34.728 mm, and the radius of curvature of the image side is 24.363 mm.

[0023] It is understandable that in Figure 1 In the embodiment shown, the optical axis transmission direction is from left to right, the left side of the lens is the object side, and the right side is the image side, such as the S1 surface of the first lens 11 is the object side surface, and the S2 surface is the image side surface. Other lenses are not described in detail.

[0024] In one embodiment, the first lens 11, the fifth lens 15 and the lens meet the following conditions: f1 / f<1, 1<f5 / f<2; wherein 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.

[0025] Table 1 Component parameters It should be noted that the above lenses are all made of domestic optical materials. Meanwhile, in a specific embodiment, the first lens 11 and the fourth lens 14 are both made of IRG202 material.

[0026] As shown in Table 1, the object side surfaces of the first lens 11, the second lens 12, the third lens 13, the fourth lens 14 and the fifth lens 15 are all spherical surfaces, and the image side surfaces are all aspherical surfaces, and all the aspherical surfaces satisfy the aspherical surface formula: Among them, z represents the distance of the surface from the vertex of the surface in the direction of 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-order, sixth-order, eighth-order, tenth-order and twelfth-order surface coefficients respectively. At the same time, the aspherical data of each lens are shown in Table 2.

[0027] Table 2 Aspheric surface data Figure 2 and Figure 3They are the MTF diagram and spot diagram of the two-color composite uncooled athermal infrared lens at a wavelength of 3~5μm; Figure 4 and Figure 5 These are the MTF and point diagrams of the dual-color composite uncooled athermal infrared lens at wavelengths of 8 to 12 μm. In the MTF diagram, the horizontal axis represents different spatial frequencies, and the vertical axis represents the modulation degree. Combined with the drawings, it can be seen that the lens corrects various aberrations in each band, so that both the center and edge markets have sufficient resolution.

[0028] In summary, the working band of the two-color composite uncooled athermal infrared lens provided by the present application is 3~5μm and 8~12μm; the focal length is f=75mm; the F number is 0.9. The lens provided by the present application has a simple structure, a large target surface, and clear imaging, is suitable for a two-color movement, and can be used with a resolution of 1280×1024 and a 12μm uncooled detector.

[0029] Although the embodiments of the present application have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present application, and that the scope of the present application is defined by the appended claims and their equivalents.

Claims

1. A two-color composite uncooled athermal infrared lens, characterized in that: 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 which are arranged in sequence along the transmission direction of the optical axis; the first lens and the fourth lens are both positive meniscus lenses with convex surfaces facing the object side, and the second lens, the third lens and the fifth lens are both negative meniscus lenses with convex surfaces facing the object side; the air gap between the first lens and the second lens is 0.5mm, the air gap between the second lens and the third lens is 18.2mm, the air gap between the third lens and the fourth lens is 31.89mm, and the air gap between the fourth lens and the fifth lens is 0.5mm.

2. The dual-color composite uncooled athermal infrared lens according to claim 1, characterized in that: The center thickness of the first lens is 16.5mm, the radius of curvature of the object side is 60.78mm, and the radius of curvature of the image side is 239.376mm; the center thickness of the second lens is 4mm, the radius of curvature of the object side is 111.71mm, and the radius of curvature of the image side is 78.161mm; the center thickness of the third lens is 3.2mm, the radius of curvature of the object side is 123.785mm, and the radius of curvature of the image side is 50.86mm; the center thickness of the fourth lens is 13mm, the radius of curvature of the object side is 37.662mm, and the radius of curvature of the image side is 168.539mm; the center thickness of the fifth lens is 4.8mm, the radius of curvature of the object side is 34.728mm, and the radius of curvature of the image side is 24.363mm.

3. The dual-color composite uncooled athermal infrared lens according to claim 1, characterized in that: Also included is an aperture, which is disposed between the first lens and the second lens.

4. The dual-color composite uncooled athermal infrared lens according to claim 1, characterized in that: The first lens and the lens meet the following condition: f1 / f<1, where f1 is the effective focal length of the first lens, and f is the effective focal length of the lens.

5. The dual-color composite uncooled athermal infrared lens according to claim 1, characterized in that: The fifth lens and the lens meet the following condition: 1<f5 / f<2, wherein f5 is the effective focal length of the fifth lens, and f is the effective focal length of the lens.

6. The dual-color composite uncooled athermal infrared lens according to claim 1, characterized in that: The focal length of the lens is 75 mm and the F number is 0.

9.

7. The dual-color composite uncooled athermal infrared lens according to claim 1, characterized in that: The lens adopts an optical athermal design.

8. An imaging device, characterized in that: It comprises the two-color composite uncooled athermal infrared lens as described in any one of claims 1 to 7 and a detector for receiving the image formed by the lens.

9. The imaging device according to claim 8, characterized in that: The number of pixels of the detector is 1280×1024, and the pixel size is 12 μm.

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