Long-wave uncooled infrared continuous zoom lens and imaging system

Abstract

The invention provides an imaging system which comprises a long-wave uncooled infrared continuous zoom lens, 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, and the second lens and the third lens can reciprocate in the optical axis direction. The first lens, the second lens, the third lens, the fourth lens, the first lens, the second lens, the third lens, the fourth lens, the fourth lens, the fifth lens, the sixth lens, the seventh lens, the seventh lens, the seventh lens, the seventh lens, the seventh lens, the seventh lens, the seventh lens, the seventh lens, the seventh lens, the seventh lens, the seventh lens, the seventh lens, the seventh lens, the seventh lens, the seventh lens, the seventh lens, the seventh lens, the seventh lens, the seventh lens, the seventh lens, the seventh lens, the seventh lens, the seventh lens, the seventh lens and the seventh lens are sequentially arranged from top to bottom. And the air gap between the fourth lens and the fifth lens is 46.82 mm. The lens can give consideration to the measurement range and measurement details, is clear in imaging, and can be suitable for monitoring subject matters with different sizes.

Description

Technical Field

[0001] The present application belongs to the field of infrared optical technology, and specifically relates to a long-wave uncooled infrared continuous zoom lens and an imaging system. Background Art

[0002] Infrared thermal imagers can convert the thermal radiation energy emitted by an object into electronic signals, and then obtain the temperature distribution information of the object. When current passes through electronic components, part of the electrical energy will be converted into internal energy, generating a heating phenomenon of varying degrees. In many cases, the heating of electronic components can be used to evaluate the efficiency of the circuit or diagnose faults. At this time, long-wave infrared microscopes based on heat detection become an indispensable tool. Although the magnification can be changed by using a fixed-focus lens and changing the object distance and image distance, under the condition of microscopic imaging with a very close object distance, changing the object distance and image distance will lead to deterioration of aberration and degradation of lens imaging quality. However, the use of a lens that can continuously zoom can take into account both the measurement range and measurement details, and can be applied to the monitoring of targets of different sizes. Therefore, it is necessary to design a long-wave uncooled infrared continuous zoom lens. Summary of the invention

[0003] Based on this, it is necessary to provide a long-wave uncooled infrared continuous zoom lens and imaging system that can take into account both measurement range and measurement details.

[0004] The technical solution proposed in this application is: A long-wave uncooled infrared continuous zoom lens comprises a first lens, a second lens, a third lens, a fourth lens and a fifth lens which are sequentially arranged along an optical axis transmission direction, wherein the second lens and the third lens can both move back and forth along the optical axis direction, and an air gap between the first lens and the second lens is 29.221-62.672 mm, an air gap between the second lens and the third lens is 7.845-62.57 mm, an air gap between the third lens and the fourth lens is 7.577-28.851 mm, an air gap between the first lens and the fourth lens is 110.048 mm, and an air gap between the fourth lens and the fifth lens is 46.82 mm.

[0005] Further, the center thickness of the first lens is 11.3 mm, the object side curvature radius is 147.22 mm, and the image side curvature radius is 230.75 mm; the center thickness of the second lens is 3 mm, the object side curvature radius is -206.11 mm, and the image side curvature radius is 143.84 mm; the center thickness of the third lens is 7.68 mm, the object side curvature radius is 226.28 mm, and the image side curvature radius is -206.31 mm; the center thickness of the fourth lens is 3 mm, the object side curvature radius is -59.46 mm, and the image side curvature radius is -74.19 mm; the center thickness of the fifth lens is 3.7 mm, the object side curvature radius is 100 mm, and the image side curvature radius is 348.16 mm.

[0006] Further, the focal length is 30~150mm; When the focal length is 30 mm, the air interval between the first lens and the second lens is 29.221 mm, the air interval between the second lens and the third lens is 62.57 mm, and the air interval between the third lens and the fourth lens is 7.577 mm; When the focal length is 90 mm, the air gap between the first lens and the second lens is 54.979 mm, the air gap between the second lens and the third lens is 24.155 mm, and the air gap between the third lens and the fourth lens is 20.234 mm; When the focal length is 150 mm, the air space between the first lens and the second lens is 62.672 mm, the air space between the second lens and the third lens is 7.845 mm, and the air space between the third lens and the fourth lens is 28.851 mm.

[0007] Furthermore, the first lens, the second lens, the third lens, the fourth lens and the fifth lens are made of germanium glass.

[0008] Furthermore, the first lens and the fifth lens are both meniscus positive lenses with their convex surfaces facing the object side, the second lens is a double concave negative lens, the third lens is a double convex positive lens, and the fourth lens is a meniscus positive lens with its convex surface facing the image side.

[0009] Furthermore, the object side surface of the second lens, the object side surface of the third lens, the object side surface of the fourth lens, and the image side surface of the fifth lens are all aspherical surfaces, and satisfy the aspherical surface formula: Among them, Z is the distance vector height from the vertex of the aspherical surface when the aspherical surface is at a height r along the optical axis; c=1 / R; R is the paraxial curvature fitting radius of the mirror; k is the cone coefficient; A, B, C, D, and E are high-order aspherical coefficients.

[0010] Furthermore, the lens has an operating band of 8-12 μm and an F number of 1.2.

[0011] An imaging system comprises the long-wave uncooled infrared continuous zoom lens as described above and a detector for receiving images formed by the long-wave uncooled infrared continuous zoom lens.

[0012] Furthermore, the detector is a non-cooled detector, and the resolution of the detector is 640×512, and the pixel size is 17 μm.

[0013] The imaging system provided by the present application includes a long-wave uncooled infrared continuous zoom lens and a detector. The focal length of the lens is 30-150 mm, the working band is 8-12 μm, and the F number is 1.2. The detector is an uncooled detector, and the resolution of the detector is 640×542, and the pixel size is 17 μm. At the same time, the lens can take into account both the measurement range and the measurement details, and the imaging is clear, and it can be applied to the monitoring of objects of different sizes. 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 diagram of the lens composition of the imaging system provided for this application; Figure 2 The optical path diagram of the imaging system provided in this application when the focal length is 30 mm; Figure 3 The optical path diagram of the imaging system provided in this application when the focal length is 90 mm; Figure 4 The optical path diagram of the imaging system provided in this application when the focal length is 150mm; Figure 5 MTF diagram of the long-wave uncooled infrared continuous zoom lens provided for this application at a focal length of 30mm; Figure 6 The spot diagram of the long-wave uncooled infrared continuous zoom lens provided for this application when the focal length is 30mm; Figure 7 MTF diagram of the long-wave uncooled infrared continuous zoom lens provided for this application at a focal length of 90mm; Figure 8The spot diagram of the long-wave uncooled infrared continuous zoom lens provided for this application when the focal length is 90mm; Fig. 9 MTF diagram of the long-wave uncooled infrared continuous zoom lens provided for this application at a focal length of 150mm; Fig.10 The spot diagram of the long-wave uncooled infrared continuous zoom lens provided for this application when the focal length is 150mm; Fig.11 This is a schematic diagram of the cam curve for the movement of the second lens and the third lens in the long-wave uncooled infrared continuous zoom lens provided in the present application.

[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] The present application provides an imaging system, which includes a long-wave uncooled infrared continuous zoom lens and a detector. The focal length of the lens is 30~150mm, the working band is 8~12μm, and the F number is 1.2; the detector is an uncooled detector, and the resolution of the detector is 640×542, and the pixel size is 17μm.

[0019] like Figures 1 to 4 As shown, the lens comprises a first lens 11, a second lens 12, a third lens 13, a fourth lens 14 and a fifth lens 15 which are sequentially arranged along the optical axis transmission direction. The second lens 12 and the third lens 13 can both move back and forth along the optical axis direction, and the air interval between the first lens 11 and the second lens 12 is 29.221-62.672 mm, the air interval between the second lens 12 and the third lens 13 is 7.845-62.57 mm, the air interval between the third lens 13 and the fourth lens 14 is 7.577-28.851 mm, the air interval between the first lens 11 and the fourth lens 14 is 110.048 mm, and the air interval between the fourth lens 14 and the fifth lens 15 is 46.82 mm.

[0020] Specifically, when the focal length is 30 mm, the air interval between the first lens 11 and the second lens 12 is 29.221 mm, the air interval between the second lens 12 and the third lens 13 is 62.57 mm, and the air interval between the third lens 13 and the fourth lens 14 is 7.577 mm.

[0021] When the focal length is 90 mm, the air interval between the first lens 11 and the second lens 12 is 54.979 mm, the air interval between the second lens 12 and the third lens 13 is 24.155 mm, and the air interval between the third lens 13 and the fourth lens 14 is 20.234 mm.

[0022] When the focal length is 150 mm, the air interval between the first lens 11 and the second lens 12 is 62.672 mm, the air interval between the second lens 12 and the third lens 13 is 7.845 mm, and the air interval between the third lens 13 and the fourth lens 14 is 28.851 mm.

[0023] In one embodiment, the detector includes a protection window 21 and a detector focal plane array 22, such as Figure 1 As shown, 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, and then forms an image on the detector focal plane array 22 through the protective window 21. In practical applications, the air gap between the fifth lens 15 and the protective window 21 is 18.63 mm.

[0024] In one embodiment, the first lens 11 and the fifth lens 15 are both positive meniscus lenses with convex surfaces facing the object side, the second lens 12 is a double concave negative lens, the third lens 13 is a double convex positive lens, and the fourth lens 14 is a positive meniscus lens with convex surfaces facing the image side.

[0025] Further, the center thickness of the first lens 11 is 11.3 mm, the radius of curvature of the object side is 147.22 mm, and the radius of curvature of the image side is 230.75 mm; the center thickness of the second lens 12 is 3 mm, the radius of curvature of the object side is -206.11 mm, and the radius of curvature of the image side is 143.84 mm; the center thickness of the third lens 13 is 7.68 mm, the radius of curvature of the object side is 226.28 mm, and the radius of curvature of the image side is -206.31 mm; the center thickness of the fourth lens 14 is 3 mm, the radius of curvature of the object side is -59.46 mm, and the radius of curvature of the image side is -74.19 mm; the center thickness of the fifth lens 15 is 3.7 mm, the radius of curvature of the object side is 100 mm, and the radius of curvature of the image side is 348.16 mm.

[0026] It can be understood that the incident direction of the light is the object side, and the outgoing direction is the image side. Figure 1For example, along the optical axis 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. Other lenses are not described here.

[0027] In one embodiment, the first lens 11, the second lens 12, the third lens 13, the fourth lens 14 and the fifth lens 15 are all made of germanium glass. Parameters of each lens can be found in Table 1.

[0028] Table 1 Lens parameters In one embodiment, the object side surface of the second lens 12, the object side surface of the third lens 13, the object side surface of the fourth lens 14, and the image side surface of the fifth lens 15 are all aspherical surfaces and satisfy the aspherical surface formula Among them, Z is the distance vector height from the vertex of the aspherical surface when the aspherical surface is at a height r along the optical axis; c=1 / R; R is the paraxial curvature fitting radius of the mirror; k is the cone coefficient; A, B, C, D, and E are high-order aspherical coefficients.

[0029] Table 2 Aspheric coefficients Figure 5 This is the MTF diagram when the focal length is 30mm. Figure 6 This is the spot diagram when the focal length is 30mm; Figure 7 This is the MTF diagram when the focal length is 90mm. Figure 8 This is the spot diagram when the focal length is 90mm; Fig. 9 This is the MTF diagram when the focal length is 150mm. Fig.10 This is the spot diagram when the focal length is 150mm. In the MTF diagram, the horizontal axis represents different spatial frequencies and the vertical axis represents the modulation degree. It can be seen that the MTF is close to the diffraction limit, the RMS of the diffuse spot is smaller than the Airy disk diameter, and the image quality is good.

[0030] Fig.11The figure is a schematic diagram of the cam curve of the movement of the second lens 12 and the third lens 13, q1 is the movement curve of the second lens 12, and the ordinate corresponding to q1 is the sum of the air gap between the second lens 12 and the first lens 11 and the center thickness of the first lens 11; q2 is the movement curve of the third lens, and the ordinate corresponding to q2 is the sum of the air gap between the third lens 13 and the first lens 11 and the center thickness of the first lens 11; the abscissa is 200 points selected during the movement of the second lens 12 and the third lens 13. In the actual operation process, the third lens 13 moves with the second lens 12, and it can be seen from the figure that when q1 is smooth, q2 also remains smooth without any tortuosity fluctuations, so it can be determined that the continuous zoom lens is smooth and has no jamming during the zooming process.

[0031] In summary, the imaging system provided by the present application includes a long-wave uncooled infrared continuous zoom lens and a detector. The focal length of the lens is 30-150 mm, the working band is 8-12 μm, and the F number is 1.2. The detector is an uncooled detector, and the resolution of the detector is 640×542, and the pixel size is 17 μm. At the same time, the lens can take into account both the measurement range and the measurement details, and the imaging is clear, and it can be applied to the monitoring of objects of different sizes.

[0032] 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 long-wave uncooled infrared continuous zoom lens, characterized in that: It 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 second lens and the third lens can both move back and forth along the optical axis direction, and the air gap between the first lens and the second lens is 29.221~62.672mm, the air gap between the second lens and the third lens is 7.845~62.57mm, the air gap between the third lens and the fourth lens is 7.577~28.851mm, the air gap between the first lens and the fourth lens is 110.048mm, and the air gap between the fourth lens and the fifth lens is 46.82mm.

2. The long-wave uncooled infrared continuous zoom lens according to claim 1, characterized in that: The center thickness of the first lens is 11.3mm, the radius of curvature of the object side is 147.22mm, and the radius of curvature of the image side is 230.75mm; the center thickness of the second lens is 3mm, the radius of curvature of the object side is -206.11mm, and the radius of curvature of the image side is 143.84 mm; the center thickness of the third lens is 7.68mm, the radius of curvature of the object side is 226.28mm, and the radius of curvature of the image side is -206.31mm; the center thickness of the fourth lens is 3mm, the radius of curvature of the object side is -59.46mm, and the radius of curvature of the image side is -74.19mm; the center thickness of the fifth lens is 3.7mm, the radius of curvature of the object side is 100mm, and the radius of curvature of the image side is 348.16mm.

3. The long-wave uncooled infrared continuous zoom lens according to claim 1, characterized in that: Focal length is 30~150mm; When the focal length is 30 mm, the air interval between the first lens and the second lens is 29.221 mm, the air interval between the second lens and the third lens is 62.57 mm, and the air interval between the third lens and the fourth lens is 7.577 mm; When the focal length is 90 mm, the air gap between the first lens and the second lens is 54.979 mm, the air gap between the second lens and the third lens is 24.155 mm, and the air gap between the third lens and the fourth lens is 20.234 mm; When the focal length is 150 mm, the air space between the first lens and the second lens is 62.672 mm, the air space between the second lens and the third lens is 7.845 mm, and the air space between the third lens and the fourth lens is 28.851 mm.

4. The long-wave uncooled infrared continuous zoom lens according to claim 1, characterized in that: The first lens, the second lens, the third lens, the fourth lens and the fifth lens are made of germanium glass.

5. The long-wave uncooled infrared continuous zoom lens according to claim 1, characterized in that: The first lens and the fifth lens are both positive meniscus lenses with their convex surfaces facing the object side, the second lens is a double concave negative lens, the third lens is a double convex positive lens, and the fourth lens is a positive meniscus lens with its convex surface facing the image side.

6. The long-wave uncooled infrared continuous zoom lens according to claim 1, characterized in that: The object side surface of the second lens, the object side surface of the third lens, the object side surface of the fourth lens, and the image side surface of the fifth lens are all aspherical surfaces, and satisfy the aspherical surface formula: Among them, Z is the distance vector height from the vertex of the aspherical surface when the aspherical surface is at a height r along the optical axis; c=1 / R; R is the paraxial curvature fitting radius of the mirror; k is the cone coefficient; A, B, C, D, and E are high-order aspherical coefficients.

7. The long-wave uncooled infrared continuous zoom lens according to claim 1, characterized in that: The lens has an operating band of 8 to 12 μm and an F number of 1.

2.

8. An imaging system, characterized in that: The invention comprises the long-wave uncooled infrared continuous zoom lens as claimed in any one of claims 1 to 7 and a detector for receiving images formed by the long-wave uncooled infrared continuous zoom lens.

9. The imaging system according to claim 8, characterized in that The detector is a non-cooling detector, and the resolution of the detector is 640×512, and the pixel size is 17 μm.

Images