Long-wave uncooled infrared continuous zoom lens and imaging system

Abstract

The application provides an imaging system, comprising a long-wave uncooled infrared continuous zoom lens, the lens comprising 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 second lens and the third lens can reciprocate along the direction of the optical axis, and the air gap between the first lens and the second lens is 29.221-62.672 mm, the air gap between the second lens and the third lens is 7.845-62.57 mm, the air gap between the third lens and the fourth lens is 7.577-28.851 mm, the air gap between the first lens and the fourth lens is 110.048 mm, and the air gap between the fourth lens and the fifth lens is 46.82 mm. The lens can balance the measurement range and the measurement details, the imaging is clear, and the lens can be applied to the monitoring of different size targets.

Description

Technical Field

[0001] This application belongs to the field of infrared optical technology, specifically relating to a long-wavelength uncooled infrared continuous zoom lens and imaging system. Background Technology

[0002] Infrared thermal imagers convert the thermal radiation energy emitted by an object into electronic signals, thereby acquiring information about the object's temperature distribution. When an electric current passes through electronic components, some electrical energy is converted into internal energy, generating heat of varying degrees. In many cases, the heating status of electronic components can be used to assess circuit efficiency or diagnose faults, making long-wavelength infrared microscopy based on thermal detection an indispensable tool. While fixed-focus lenses can achieve magnification by changing the object distance and image distance, this leads to aberration deterioration and decreased image quality under microscopic imaging conditions where the object distance is very close. Lenses capable of continuous zoom, however, can balance measurement range and detail, making them suitable for monitoring objects of varying sizes. Therefore, it is necessary to design long-wavelength uncooled infrared continuous zoom lenses. Summary of the Invention

[0003] Therefore, it is necessary to provide a long-wavelength 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 as follows: A long-wavelength uncooled infrared continuous zoom 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 second lens and the third lens are both capable of reciprocating along the optical axis direction. 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.

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

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

[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 biconcave negative lens, the third lens is a biconvex 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 formula: Where Z is the distance vector from the vertex of the aspherical surface at a height r along the optical axis; c = 1 / R; R is the paraxial curvature fitting radius of the mirror; k is the conic coefficient; A, B, C, D, and E are higher-order aspherical coefficients.

[0010] Furthermore, the lens operates in the 8~12μm wavelength range and has an F-number of 1.2.

[0011] An imaging system includes a long-wavelength uncooled infrared continuous zoom lens as described above and a detector for receiving images from the long-wavelength uncooled infrared continuous zoom lens.

[0012] Furthermore, the detector is an uncooled detector, and the detector has a resolution of 640×512 and a pixel size of 17μm.

[0013] The imaging system provided in this application includes a long-wavelength uncooled infrared continuous zoom lens and a detector. The lens has a focal length of 30-150mm, an operating wavelength of 8-12μm, and an F-number of 1.2. The detector is an uncooled detector with a resolution of 640×542 and a pixel size of 17μm. Furthermore, the lens balances measurement range and detail, provides clear imaging, and is suitable for monitoring objects of different sizes. Attached Figure Description

[0014] 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.

[0015] Figure 1 A lens composition diagram of the imaging system provided in this application; Figure 2 The optical path diagram of the imaging system provided in this application at a focal length of 30mm; Figure 3 The optical path diagram of the imaging system provided in this application at a focal length of 90mm; Figure 4 The optical path diagram of the imaging system provided in this application at a focal length of 150mm; Figure 5 MTF diagram of the long-wave uncooled infrared continuous zoom lens provided in this application at a focal length of 30mm; Figure 6 A dot plot of the long-wave uncooled infrared continuous zoom lens provided in this application at a focal length of 30mm. Figure 7 MTF diagram of the long-wave uncooled infrared continuous zoom lens provided in this application at a focal length of 90mm; Figure 8A dot plot of the long-wave uncooled infrared continuous zoom lens provided in this application at a focal length of 90mm. Figure 9 MTF diagram of the long-wave uncooled infrared continuous zoom lens provided in this application at a focal length of 150mm; Figure 10 A dot plot of the long-wave uncooled infrared continuous zoom lens provided in this application at a focal length of 150mm. Figure 11 This is a schematic diagram of the cam curves for the movement of the second and third lenses in the long-wave uncooled infrared continuous zoom lens provided in this application.

[0016] Label Explanation: 11. First lens; 12. Second lens; 13. Third lens; 14. Fourth lens; 15. Fifth lens; 21. Protective window; 22. Detector focal plane array. Detailed Implementation

[0017] 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.

[0018] This application provides an imaging system, which includes a long-wave uncooled infrared continuous zoom lens and a detector. The lens has a focal length of 30~150mm, an operating wavelength of 8~12μm, and an F number of 1.2. The detector is an uncooled detector with a resolution of 640×542 and a pixel size of 17μm.

[0019] like Figures 1 to 4 As shown, the lens includes a first lens 11, a second lens 12, a third lens 13, a fourth lens 14, and a fifth lens 15 arranged sequentially along the optical axis transmission direction. The second lens 12 and the third lens 13 are both capable of reciprocating along the optical axis direction. The air gap between the first lens 11 and the second lens 12 is 29.221~62.672mm, the air gap between the second lens 12 and the third lens 13 is 7.845~62.57mm, the air gap between the third lens 13 and the fourth lens 14 is 7.577~28.851mm, the air gap between the first lens 11 and the fourth lens 14 is 110.048mm, and the air gap between the fourth lens 14 and the fifth lens 15 is 46.82mm.

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

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

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

[0023] In one embodiment, the detector includes a protective window 21 and a detector focal plane array 22, such as Figure 1 As shown, the light beam passes sequentially from left to right through the first lens 11, the second lens 12, the third lens 13, the fourth lens 14, and the fifth lens 15, and then through the protective window 21 to form an image on the detector focal plane array 22. 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 meniscus positive lenses with their convex surfaces facing the object side, the second lens 12 is a biconcave negative lens, the third lens 13 is a biconvex positive lens, and the fourth lens 14 is a meniscus positive lens with its convex surface facing the image side.

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

[0026] It is understandable that the incident direction of light is on the object side, and the exit direction is on the image side. With... 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 will not be described in detail 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. The parameters of each lens can be found in Table 1.

[0028] Table 1 Parameters of each lens 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 formula. Where Z is the distance vector from the vertex of the aspherical surface at a height r along the optical axis; c = 1 / R; R is the paraxial curvature fitting radius of the mirror; k is the conic coefficient; A, B, C, D, and E are higher-order aspherical coefficients.

[0029] Table 2 Aspherical Coefficients Figure 5 This is the MTF chart when the focal length is 30mm. Figure 6 This is a dot plot when the focal length is 30mm; Figure 7 This is the MTF chart at a focal length of 90mm. Figure 8 This is a dot plot when the focal length is 90mm; Figure 9 This is the MTF chart at a focal length of 150mm. Figure 10 This is a dot plot at a focal length of 150mm. In the MTF plot, the horizontal axis represents different spatial frequencies, and the vertical axis represents modulation. It can be seen that the MTF is close to the diffraction limit, the root mean square of the diffuse spot is smaller than the Airy disk diameter, and the image quality is good.

[0030] Figure 11This diagram illustrates the cam curves of the movement of the second lens 12 and the third lens 13. q1 represents the movement curve of the second lens 12, with the vertical axis corresponding to q1 being 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 represents the movement curve of the third lens, with the vertical axis corresponding to q2 being 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 horizontal axis represents 200 points selected during the movement of the second lens 12 and the third lens 13. In actual operation, the third lens 13 moves with the second lens 12. As can be seen in the diagram, when q1 is smooth, q2 also remains smooth without any twists or fluctuations. Therefore, it can be determined that the continuous zoom lens operates smoothly without any stuttering during zooming.

[0031] In summary, the imaging system provided in this application includes a long-wavelength uncooled infrared continuous zoom lens and a detector. The lens has a focal length of 30-150mm, an operating wavelength of 8-12μm, and an F-number of 1.2. The detector is an uncooled detector with a resolution of 640×542 and a pixel size of 17μm. Furthermore, the lens balances measurement range and detail, provides clear imaging, and is suitable for monitoring targets of different sizes.

[0032] 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-wavelength uncooled infrared continuous zoom lens, characterized in that, It consists 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 second lens and the third lens can reciprocate along the optical axis direction. 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. The first lens has a center thickness of 11.3 mm, an object-side radius of curvature of 147.22 mm, and an image-side radius of curvature of 230.75 mm; the second lens has a center thickness of 3 mm, an object-side radius of curvature of -206.11 mm, and an image-side radius of curvature of 143.84 mm; the third lens has a center thickness of 7.68 mm, an object-side radius of curvature of 226.28 mm, and an image-side radius of curvature of -206.31 mm; the fourth lens has a center thickness of 3 mm, an object-side radius of curvature of -59.46 mm, and an image-side radius of curvature of -74.19 mm; and the fifth lens has a center thickness of 3.7 mm, an object-side radius of curvature of 100 mm, and an image-side radius of curvature of 348.16 mm.

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

3. The long-wavelength 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.

4. The long-wavelength uncooled infrared continuous zoom lens according to claim 1, characterized in that, 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 biconcave negative lens, the third lens is a biconvex positive lens, and the fourth lens is a meniscus positive lens with its convex surface facing the image side.

5. The long-wavelength 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 formula: Where Z is the distance vector from the vertex of the aspherical surface at a height r along the optical axis; c = 1 / R; R is the paraxial curvature fitting radius of the mirror; k is the conic coefficient; A, B, C, D, and E are higher-order aspherical coefficients.

6. The long-wavelength uncooled infrared continuous zoom lens according to claim 1, characterized in that, The lens operates in the 8~12μm wavelength range and has an F-number of 1.

2.

7. An imaging system, characterized in that, It includes the long-wave uncooled infrared continuous zoom lens as described in any one of claims 1-6 and a detector for receiving the image formed by the long-wave uncooled infrared continuous zoom lens.

8. The imaging system according to claim 7, characterized in that, The detector is an uncooled detector with a resolution of 640×512 and a pixel size of 17μm.

Images