A dual-color composite non-cooled athermal infrared lens and imaging device

Abstract

The application provides a dual-color composite non-cooled athermal infrared lens, which is suitable for a spectral range of 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 arranged in sequence 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, and the second lens, the third lens and the fifth lens are all meniscus negative lenses with the convex surface 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 application has the advantages of simple structure, large target surface, clear imaging, adaptation to a dual-color core, and matching with a resolution of 1280x1024 and a 12 mu m non-cooled detector. The application also discloses an imaging device.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of infrared optical equipment, and particularly relates to a dual-color composite non-cooled heat-difference infrared lens and an imaging device. BACKGROUND

[0002] With the rapid development of science and technology, a dual-color integrated non-cooled infrared core in the middle wave 3-5 mu m and long wave 8-14 mu m becomes inevitable. The dual-color infrared thermal imager adopting the core is widely used in many fields such as industry, meteorology, automatic driving and aerospace, but there are few infrared lenses with dual-color cores on the market. SUMMARY

[0003] Based on this, the application provides a dual-color composite non-cooled heat-difference infrared lens and an imaging device.

[0004] The technical scheme provided by the application is as follows:

[0005] A dual-color composite non-cooled heat-difference infrared lens, the spectral range of which is 3-5 mu m and 8-12 mu m, the lens comprising first, second, third, fourth and fifth lenses arranged in sequence along the transmission direction of the optical axis; the first and fourth lenses are both convex moon positive lenses with the convex surface facing the object side, and the second, third and fifth lenses are all convex moon negative lenses with the convex surface facing the object side; the air gap between the first and second lenses is 0.5 mm, the air gap between the second and third lenses is 18.2 mm, the air gap between the third and fourth lenses is 31.89 mm, and the air gap between the fourth and fifth lenses is 0.5 mm.

[0006] Further, the center thickness of the first lens is 16.5 mm, the curvature radius of the object side surface is 60.78 mm, and the curvature radius of the image side surface is 239.376 mm; the center thickness of the second lens is 4 mm, the curvature radius of the object side surface is 111.71 mm, and the curvature radius of the image side surface is 78.161; the center thickness of the third lens is 3.2 mm, the curvature radius of the object side surface is 123.785 mm, and the curvature radius of the image side surface is 50.86 mm; the center thickness of the fourth lens is 13 mm, the curvature radius of the object side surface is 37.662 mm, and the curvature radius of the image side surface is 168.539 mm; and the center thickness of the fifth lens is 4.8 mm, the curvature radius of the object side surface is 34.728 mm, and the curvature radius of the image side surface is 24.363 mm.

[0007] Further, a diaphragm is arranged between the first and second lenses.

[0008] Further, the first lens and the lens satisfy the following condition: f1 / f<1, wherein f1 is an effective focal length of the first lens, and f is an effective focal length of the lens.

[0009] Further, the fifth lens and the lens satisfy the following condition: 1

[0010] Further, the lens has a focal length of 75 mm and an F number of 0.9.

[0011] Further, the lens adopts optical athermalization design.

[0012] An imaging device includes the dual-color composite non-cooled athermalization infrared lens and a detector receiving an image formed by the lens.

[0013] Further, the detector has a pixel number of 1280x1024 and a pixel size of 12 μm.

[0014] The lens structure provided by the present application is simple, has a large target surface, and forms a clear image, is suitable for a dual-color core, and can match a non-cooled detector with a resolution of 1280x1024 and a pixel size of 12 μm. BRIEF DESCRIPTION OF DRAWINGS

[0015] The accompanying drawings are included to provide a further understanding of the present application, and constitute a part of the specification, illustrate the present application, and are used to explain the present application, and do not constitute a limitation on the present application.

[0016] Figure 1 A structure schematic diagram of an imaging device provided by an embodiment of the present application is shown in FIG. 1.

[0017] Figure 2 An MTF diagram of the dual-color composite non-cooled athermalization infrared lens provided by an embodiment of the present application at a wavelength of 3-5 μm is shown in FIG. 2.

[0018] Figure 3 A point column diagram of the dual-color composite non-cooled athermalization infrared lens provided by an embodiment of the present application at a wavelength of 3-5 μm is shown in FIG. 3.

[0019] Figure 4 An MTF diagram of the dual-color composite non-cooled athermalization infrared lens provided by an embodiment of the present application at a wavelength of 8-12 μm is shown in FIG. 4.

[0020] Figure 5 A point column diagram of the dual-color composite non-cooled athermalization infrared lens provided by an embodiment of the present application at a wavelength of 8-12 μm is shown in FIG. 5.

[0021] Label explanation:

[0022] 11, first lens; 12, second lens; 13, third lens; 14, fourth lens; 15, fifth lens; 21, protective window; 22, detector focal plane array. DETAILED DESCRIPTION

[0023] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative work fall within the scope of protection of the present application.

[0024] An embodiment of the present application provides an imaging device, which comprises a dual-color composite uncooled athermal infrared lens and a detector for receiving an image formed by the lens. The focal length of the lens is 75 mm, the applicable spectral range is 3-5 μm and 8-12 μm, and the F number is 0.9. The detector is a non-cooled detector, and the number of pixels of the detector is 1280x1024, and the pixel size is 12 μm.

[0025] Referring to FIG. 1, Figure 1 The lens comprises, in sequence along the transmission direction of the optical axis, a first lens 11, a second lens 12, a third lens 13, a fourth lens 14, and a fifth lens 15. The first lens 11 and the fourth lens 14 are both meniscus positive lenses with the convex surface facing the object side, and the second lens 12, the third lens 13, and the fifth lens 15 are all meniscus negative lenses with the convex surface facing the object side. Further, the detector comprises, in sequence, a protective window 21 and a detector focal plane array 22, so as to Figure 1 For example, 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 in sequence from left to right, and then forms an image on the detector focal plane array 22 through the protective window 21.

[0026] In an embodiment, the lens further comprises a diaphragm, which is arranged between the first lens 11 and the second lens 12. Further, the lens adopts optical athermalization design.

[0027] 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 air gaps described above are air gaps on the optical axis.

[0028] Further, the central thickness of the first lens 11 is 16.5 mm, the object-side surface radius of curvature is 60.78 mm, and the image-side surface radius of curvature is 239.376 mm; the central thickness of the second lens 12 is 4 mm, the object-side surface radius of curvature is 111.71 mm, and the image-side surface radius of curvature is 78.161; the central thickness of the third lens 13 is 3.2 mm, the object-side surface radius of curvature is 123.785 mm, and the image-side surface radius of curvature is 50.86 mm; the central thickness of the fourth lens 14 is 13 mm, the object-side surface radius of curvature is 37.662 mm, and the image-side surface radius of curvature is 168.539 mm; and the central thickness of the fifth lens 15 is 4.8 mm, the object-side surface radius of curvature is 34.728 mm, and the image-side surface radius of curvature is 24.363 mm.

[0029] It can be understood that, in the embodiment shown in the figure, 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. For example, the S1 surface of the first lens 11 is the object side surface, and the S2 surface is the image side surface. The other lenses are not described in detail. Figure 1

[0030] In one embodiment, the first lens 11, the fifth lens 15, and the lens satisfy the following conditions:

[0031] 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.

[0032] Table 1 Component parameters

[0033]

[0034] It needs to be explained in combination with Table 1 that the lenses described above 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.

[0035] As shown in Table 1, the object side surface of the first lens 11, the second lens 12, the third lens 13, the fourth lens 14, and the fifth lens 15 is a spherical surface, the image side surface is an aspherical surface, and all the aspherical surfaces satisfy the aspherical surface formula:

[0036]

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

[0038] Table 2 Aspherical surface data​

[0039]

[0040] Figure 2 and Figure 3 respectively are the MTF chart and the point column chart of the dual-color composite non-cooled achromatic infrared lens at the wavelength of 3~5μm; Figure 4 and Figure 5 respectively are the MTF chart and the point column chart of the dual-color composite non-cooled achromatic infrared lens at the wavelength of 8~12μm. In the MTF chart, the horizontal axis represents different spatial frequencies, and the vertical axis represents modulation. It can be known from the chart that the lens corrects various aberrations of each waveband, so that there is sufficient resolution at the center and the edge.

[0041] In summary, the working waveband of the dual-color composite non-cooled achromatic infrared lens provided in the application is 3~5μm and 8~12μm; the focal length f=75mm; and the F number is 0.9. The lens provided in the application has simple structure, large target surface and clear imaging, is suitable for dual-color cores, and can match a resolution of 1280×1024 and a 12μm non-cooled detector.

[0042] Although the embodiments of the application have been shown and described, it can be understood by those of ordinary skill in the art that various changes, modifications, replacements and variations can be made to the embodiments without departing from the principles and spirits of the application, and the scope of the application is defined by the appended claims and their equivalents.

Claims

1. A dual-color compound uncooled athermal infrared lens, characterized in that, The lens has an applicable spectral range of 3-5 μm and 8-12 μm, and is composed of 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 convex moon positive lenses facing the object side, and the second lens, the third lens and the fifth lens are all convex moon negative lenses 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 central thickness of the first lens is 16.5 mm, the curvature radius of the object side surface is 60.78 mm, and the curvature radius of the image side surface is 239.376 mm; the central thickness of the second lens is 4 mm, the curvature radius of the object side surface is 111.71 mm, and the curvature radius of the image side surface is 78.161 mm; the central thickness of the third lens is 3.2 mm, the curvature radius of the object side surface is 123.785 mm, and the curvature radius of the image side surface is 50.86 mm; the central thickness of the fourth lens is 13 mm, the curvature radius of the object side surface is 37.662 mm, and the curvature radius of the image side surface is 168.539 mm; and the central thickness of the fifth lens is 4.8 mm, the curvature radius of the object side surface is 34.728 mm, and the curvature radius of the image side surface is 24.363 mm.

2. The dual-color compound uncooled athermal infrared lens according to claim 1, wherein, A diaphragm is further included and arranged between the first lens and the second lens.

3. The dual-color compound uncooled athermal infrared lens of claim 1, wherein, The first lens and the lens satisfy the 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.

4. The dual-color compound uncooled athermal infrared lens of claim 1, wherein, The fifth lens and the lens satisfy the 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.

5. The dual-color compound uncooled athermal infrared lens of claim 1, wherein, The focal length of the lens is 75 mm, and the F number is 0.

9.

6. The dual-color compound uncooled athermal infrared lens of claim 1, wherein, The lens adopts optical athermalization design.

7. An image forming apparatus characterized by comprising: The application further discloses a dual-color composite non-cooled athermalization infrared lens and a detector receiving the image formed by the lens.

8. The imaging apparatus according to claim 7, characterized by The number of pixels of the detector is 1280x1024, and the pixel size is 12 μm.

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