Short-wave infrared hyperspectral telephoto lens

Abstract

The short-wave infrared hyperspectral telephoto lens is composed of six lenses, the six lenses are a positive lens, a negative lens, a negative lens, a negative lens, a positive lens and a positive lens in sequence in the light incidence direction, the focal length of the short-wave infrared hyperspectral telephoto lens is 13.94 mm, the image space F number is 2.3, the field angle is 12 degrees, and the total length is 19.25 mm; the operating wavelength range of the short-wave infrared hyperspectral telephoto lens is 1000 nm to 2500 nm. The short-wave infrared hyperspectral telephoto lens adopts an image space telecentric structure and can provide constant magnification in a certain object distance range, so that perspective errors are effectively eliminated, and emergent light of the short-wave infrared hyperspectral telephoto lens is parallel to an optical axis and can be better matched with a light splitting system. The short-wave infrared hyperspectral telephoto lens is provided with four aspherical lenses, the design freedom degree is increased, the propagation path of wave band light can be flexibly controlled, aberration such as spherical aberration and coma aberration is effectively eliminated, the imaging quality is remarkably improved, and the short-wave infrared hyperspectral telephoto lens has the advantages of being small in size, good in image quality and the like.

Description

Technical Field

[0001] This invention relates to the field of optical design technology, and in particular to a shortwave infrared hyperspectral telescope head. Background Technology

[0002] Spectral imaging technology, by reconstructing spectral "data cubes," provides a crucial data foundation for hyperspectral classification, enabling it to play a significant role in fields such as mineral exploration and environmental monitoring. However, the actual performance of this technology, especially the accuracy and stability of hyperspectral classification, is heavily constrained by the inherent characteristics of the operating wavelength: visible light-based systems are susceptible to scattering interference from atmospheric particles such as clouds, fog, and smoke, leading to a significant decrease in data quality under adverse weather conditions, directly affecting the reliability of classification models; while mid-infrared-based systems, although possessing certain penetrating capabilities, face problems such as a scarcity of effective observation channels and severe signal attenuation due to strong absorption by atmospheric water vapor, which limits the spectral information dimensions available for classification and identification.

[0003] The shortwave infrared band lies within a typical atmospheric transmission window, and its dual advantages of low atmospheric scattering and weak water vapor absorption endow it with excellent all-weather detection performance. This characteristic allows it to effectively penetrate harsh environments such as fog, haze, and snow, acquiring spectral data that is less affected by interference and more discriminative of ground features, thus providing a cleaner and more stable input source for hyperspectral classification models. Simultaneously, it performs excellently in target recognition, exhibiting high spatial resolution and strong anti-interference capabilities; these characteristics ideally complement hyperspectral technology. Therefore, this paper designs a shortwave infrared hyperspectral telescope. Summary of the Invention

[0004] This invention provides a short-wave infrared hyperspectral telescope head with an operating wavelength range of 1000nm~2500nm. The short-wave infrared hyperspectral telescope head includes six lenses, four of which are aspherical lenses. Aspherical lenses offer greater design freedom than traditional spherical lenses, allowing for flexible control of the propagation path of light in the specified wavelength range, effectively eliminating aberrations such as spherical aberration and coma, and significantly improving image quality. This invention provides a short-wave infrared hyperspectral telescope head, comprising a first positive lens, a first negative lens, a second negative lens, a third negative lens, a second positive lens, and a third positive lens arranged coaxially along the incident light direction. The first positive lens is made of HLAF3A_CDGM, with dimensions of 5.5mm < aperture diameter < 6.5mm, 3.0mm < thickness < 4.0mm, 32.0mm < first surface radius of curvature < 33.0mm, and -6.0mm < second surface radius of curvature < -5.0mm. The first surface refers to the optical surface of the lens that first contacts the light when it enters the lens, and the second surface refers to the optical surface of the lens that the light contacts when it exits after propagation through the lens. The first negative lens is made of HLAF2_CDGM, with dimensions of 5.5mm < aperture diameter < 6.5mm, 1.0mm < thickness < 2.0mm, and -6.0mm < first surface radius of curvature < -5.0mm. The second negative lens is made of HLAK51_CDGM, with a light-transmitting aperture of 5.5mm and a thickness of 1.0mm, a first surface curvature radius of -33.5mm and a second surface curvature radius of 8.0mm and a third negative lens of HQK3L_CDGM, with a light-transmitting aperture of 6.0mm and a thickness of 1.0mm and a second surface curvature radius of 2.0mm, a first surface curvature radius of 11.5mm and a second surface curvature radius of 2.5mm and a third positive lens of HZK10_CDGM, with a light-transmitting aperture of 6.5mm and a thickness of 4.0mm and a second surface curvature radius of 5.5mm and a third positive lens of HZK10_CDGM, respectively. -6.0mm < second surface curvature radius < -5.0mm; the material of the third positive lens is HZK11_CDGM, 6.5mm < light transmission diameter < 7.0mm, 2.0mm < thickness < 3.0mm, 35.5mm < first surface curvature radius < 36.5mm, 208.0mm < second surface curvature radius < 209.0mm.

[0005] Optionally, the first positive lens has a light-transmitting aperture of 6.1 mm, a thickness of 3.5 mm, a first surface radius of curvature of 32.5 mm, and a second surface radius of curvature of -5.4 mm; the first negative lens has a light-transmitting aperture of 6.0 mm, a thickness of 1.5 mm, a first surface radius of curvature of -5.4 mm, and a second surface radius of curvature of -19.2 mm; the second negative lens has a light-transmitting aperture of 6.1 mm, a thickness of 1.5 mm, a first surface radius of curvature of -33.1 mm, and a second surface radius of curvature of 8.5 mm. The third negative lens has a light-transmitting aperture of 6.4 mm, a thickness of 1.5 mm, a first surface radius of curvature of 11.9 mm, and a second surface radius of curvature of 3.1 mm; the second positive lens has a light-transmitting aperture of 6.8 mm, a thickness of 4.2 mm, a first surface radius of curvature of 6.1 mm, and a second surface radius of curvature of -5.7 mm; the third positive lens has a light-transmitting aperture of 6.6 mm, a thickness of 2.6 mm, a first surface radius of curvature of 36.1 mm, and a second surface radius of curvature of 208.7 mm.

[0006] Optionally, the first positive lens and the first negative lens form a cemented lens.

[0007] Optionally, the distance between the center of the light-emitting surface of the third positive lens and the image plane is 8.0 mm.

[0008] Optionally, the optical dimensions of the shortwave infrared hyperspectral telescope are φ6.8×19.25mm.

[0009] Optionally, the shortwave infrared hyperspectral telescope has a system focal length of 13.94 mm and an F number of 2.3.

[0010] Optionally, the operating wavelength range of the shortwave infrared hyperspectral telescope head is 1000nm~2500nm.

[0011] Optionally, the shortwave infrared hyperspectral telescope has a full field of view of 12°.

[0012] As can be seen from the above technical solutions, the embodiments of the present invention have the following advantages: 1. The shortwave infrared hyperspectral telescope head has a working wavelength range of 1000nm~2500nm and consists of 6 lenses, including four aspherical lenses. Aspherical lenses have a higher degree of design freedom than traditional spherical lenses, which can flexibly control the propagation path of light in the wavelength range, effectively eliminate aberrations such as spherical aberration and coma, and significantly improve imaging quality.

[0013] 2. The shortwave infrared hyperspectral telescope head has a focal length of 13.94mm, an F number of 2.3, a field of view of 12°, and a total optical length of 19.25mm. During the design process, all aberrations were corrected and balanced, giving it advantages such as miniaturization and excellent image quality. Attached Figure Description

[0014] Figure 1 This is a schematic diagram of the optical path structure of the shortwave infrared hyperspectral telescope head of the present invention; Figure 2 This is a dot diagram of the shortwave infrared hyperspectral telescope head of the present invention; Figure 3 The modulation transfer function of the shortwave infrared hyperspectral telescope head of the present invention; Figure reference numerals: STO - aperture stop; 1 - first positive lens; 2 - first negative lens; 3 - second negative lens; 4 - third negative lens; 5 - second positive lens; 6 - third positive lens; IMA - image plane. Detailed Implementation

[0015] To enable those skilled in the art to better understand the present invention, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of the present invention.

[0016] Please refer to Figure 1The diagram below illustrates the optical path structure of this invention. The short-wave infrared hyperspectral telescope consists of six lenses arranged in a positive-negative-negative-positive-positive configuration, including four aspherical lenses, significantly improving image quality. The six lenses are arranged coaxially along the incident light direction: a first positive lens 1, a first negative lens 2, a second negative lens 3, a third negative lens 4, a second positive lens 5, and a third positive lens 6. The first positive lens 1 is made of HLAF3A_CDGM, with a diameter of 5.5mm < aperture < 6.5mm, a thickness of 3.0mm < 4.0mm, a first surface curvature radius of 32.0mm < 33.0mm, and a second surface curvature radius of -6.0mm < -5.0mm. The first negative lens 2 is made of HLAF2_CDGM, with a diameter of 5.5mm < aperture < 6.5mm, a thickness of 1.0mm < 2.0mm, and a first surface curvature radius of -6.0mm. The second negative lens 3 is made of HLAK51_CDGM, with a light-transmitting aperture of 5.5mm and a thickness of 1.0mm, a first surface curvature radius of -33.5mm and a second surface curvature radius of 8.0mm and a third negative lens 4 made of HQK3L_CDGM, with a light-transmitting aperture of 6.0mm and a thickness of 1.0mm and a second surface curvature radius of 2.0mm, a first surface curvature radius of 11.5mm and a third surface curvature radius of 2.5mm and a third surface curvature radius of 3.5mm. The second positive lens 5 is made of HZK10_CDGM, with a light-transmitting aperture of 6.5mm and a thickness of 4.0mm and a second surface curvature radius of 5.5mm and a third surface curvature radius of 6.5mm. -6.0mm < second surface curvature radius < -5.0mm; the material of the third positive lens 6 is HZK11_CDGM, 6.5mm < light transmission diameter < 7.0mm, 2.0mm < thickness < 3.0mm, 35.5mm < first surface curvature radius < 36.5mm, 208.0mm < second surface curvature radius < 209.0mm.

[0017] In one embodiment, the first positive lens 1 has a light-transmitting aperture of 6.1 mm, a thickness of 3.5 mm, a first surface radius of curvature of 32.5 mm, and a second surface radius of curvature of -5.4 mm; the first negative lens 2 has a light-transmitting aperture of 6.0 mm, a thickness of 1.5 mm, a first surface radius of curvature of -5.4 mm, and a second surface radius of curvature of -19.2 mm; the second negative lens 3 has a light-transmitting aperture of 6.1 mm, a thickness of 1.5 mm, a first surface radius of curvature of -33.1 mm, and a second surface radius of curvature of 8.5 mm; the third negative lens 4 has a light-transmitting aperture of 6.4 mm, a thickness of 1.5 mm, and a first surface radius of curvature of -5.4 mm. The second positive lens 5 has a radius of curvature of 11.9 mm and a second surface radius of curvature of 3.1 mm. The second positive lens 5 has a aperture of 6.8 mm, a thickness of 4.2 mm, a first surface radius of curvature of 6.1 mm, and a second surface radius of curvature of -5.7 mm. The third positive lens 6 has a aperture of 6.6 mm, a thickness of 2.6 mm, a first surface radius of curvature of 36.1 mm, and a second surface radius of curvature of 208.7 mm. This results in a shortwave infrared hyperspectral telescope with a system focal length of 13.94 mm, an F-number of 2.3, a field of view of 12°, and dimensions of φ6.8 × 19.25 mm. The system boasts advantages such as miniaturization and excellent image quality.

[0018] In one embodiment, the first positive lens 1 and the first negative lens 2 form a cemented lens, and the system achieves good correction of chromatic aberration through the combination of the optical materials of the two lenses.

[0019] In one embodiment, the shortwave infrared hyperspectral telescope has a working wavelength range of 1000nm~2500nm, a focal length of 13.94mm, an F number of 2.3, a field of view of 12°, and a total optical length of 19.25mm. During the design process, all aberrations were corrected and balanced, giving it advantages such as image miniaturization and excellent image quality.

[0020] In this embodiment of the invention, the shortwave infrared hyperspectral telescope head consists of six lenses, four of which are aspherical lenses, which significantly improves the imaging quality.

[0021] Please refer to Figure 2 The figure shows a dot plot of the shortwave infrared hyperspectral telescope lens of the present invention. It can be seen from the figure that the RMS of the imaging spot at each field of view is less than 9.2 μm, indicating that the lens has good imaging quality.

[0022] Please refer to Figure 3The figure shows the optical modulation transfer function (MTF) of the short-wave infrared hyperspectral telescope head of the present invention. As can be seen from the figure, the MTF of each field of view is higher than 0.7 in the spatial frequency range of less than 30 cycles / mm, indicating that the short-wave infrared hyperspectral telescope head has good imaging quality.

[0023] The following shows the lens data for the shortwave infrared hyperspectral telescope. Table 1 shows the relevant optical parameters of each glass lens in the shortwave infrared hyperspectral telescope.

[0024] Table 1 Face number Surface type radius of curvature R Thickness D Refractive index nd / Dispersion coefficient vd K OBJ spherical endless endless STO aspherical 32.5570 3.4660 1.744 / 44.9 77.8097 S2 spherical -5.4046 1.5000 1.717 / 47.9 S3 aspherical -19.2396 3.7710 -171.5271 S4 spherical -33.1346 1.5000 1.697 / 55.5 S5 spherical 8.4756 0.1953 S6 aspherical 11.8553 1.5000 1.487 / 70.4 -34.0070 S7 aspherical 3.0788 0.3107 -6.1790 S8 aspherical 6.0744 4.2224 1.622 / 56.7 -22.3377 S9 aspherical -5.7217 0.1000 -3.3978 S10 aspherical 36.0778 2.5893 1.639 / 55.5 74.4768 S11 aspherical 208.7141 0.1004 -726.3442 S12 spherical endless 8.0000 IMA spherical endless 0.0000 The aspherical surface formula used in this embodiment of the invention is as follows: Where z is the sag of the aspherical surface at a position of radius r along the optical axis, from the vertex of the aspherical surface; c is the paraxial curvature of the aspherical surface; and k is the conic coefficient. i is the correction coefficient of the i-th order for the aspherical surface.

[0025] Table 2 shows the coefficients of higher-order terms for each aspherical surface in this embodiment.

[0026] Table 2 4th order coefficients 6th order coefficients 8th order coefficients 10th order coefficients 12th order coefficients STO 0.00056 -5.689675e-05 5.229103e-06 -2.958309e-07 -1.846870e-09 S3 -0.00036 0.00024 -1.195017e-05 -1.906358e-08 2.996364e-08 S6 0.00097 0.00011 2.718677e-07 4.108458e-07 -3.256427e-08 S7 -0.00091 8.450604e-05 6.016291e-06 -5.246070e-08 -1.964582e-08 S8 0.00227 9.687483e-05 -1.009814e-05 5.380036e-07 -1.910553e-08 S9 0.00239 -0.00012 -2.205962e-06 3.388482e-07 -1.307101e-09 S10 0.00132 -0.00035 5.457694e-06 -9.785261e-08 2.345143e-08 S11 -0.00280 5.760134e-05 -2.339901e-06 -2.753348e-08 1.094830e-08 The shortwave infrared hyperspectral telescope head described in this invention has a focal length of 13.94mm, an F-number of 2.3, a field of view of 12°, a total optical length of 19.25mm, and a wavelength range of 1000nm~2500nm. It consists of 6 lenses, including four aspherical lenses. Aspherical lenses offer greater design freedom than traditional spherical lenses, allowing for flexible control of the propagation path of light in different wavelength bands. This effectively eliminates aberrations such as spherical aberration and coma, significantly improving imaging quality and giving it advantages such as miniaturization and excellent image quality.

[0027] The specific embodiments of the present invention described above do not constitute a limitation on the scope of protection of the present invention. Any other corresponding changes and modifications made in accordance with the technical concept of the present invention should be included within the scope of protection of the claims of the present invention.

Claims

1. A shortwave infrared hyperspectral telescope head, characterized in that: It consists of a first positive lens, a first negative lens, a second negative lens, a third negative lens, a second positive lens, and a third positive lens arranged coaxially along the direction of light incidence. The first positive lens is made of HLAF3A_CDGM, with a light transmission diameter of 5.5mm and a thickness of 3.0mm, a first surface radius of curvature of 32.0mm and a second surface radius of curvature of -6.0mm and -5.0mm respectively. The material of the first negative lens is HLAF2_CDGM, with 5.5mm < aperture diameter < 6.5mm, 1.0mm < thickness < 2.0mm, -6.0mm < first surface radius of curvature < -5.0mm, and -20.0mm < second surface radius of curvature < -19.0mm; The material of the second negative lens is HLAK51_CDGM, with a light transmission diameter of 5.5mm and a thickness of 1.0mm, a first surface curvature radius of -33.5mm and a second surface curvature radius of 8.0mm and a third surface curvature radius of 9.0mm. The material of the third negative lens is HQK3L_CDGM, with a light transmission diameter of 6.0mm and a thickness of 1.0mm, a first surface curvature radius of 11.5mm and a second surface curvature radius of 2.5mm, and a diameter of 2.5mm and a third surface curvature radius of 3.5mm. The material of the second positive lens is HZK10_CDGM, with a light transmission diameter of 6.5mm and a thickness of 4.0mm, a first surface radius of curvature of 5.5mm and a second surface radius of curvature of -6.0mm and -5.0mm respectively. The material of the third positive lens is HZK11_CDGM, with a light transmission diameter of 6.5mm and a thickness of 3.0mm, a first surface curvature radius of 35.5mm and a second surface curvature radius of 208.0mm and a third surface curvature radius of 209.0mm.

2. The shortwave infrared hyperspectral telescope head as described in claim 1, characterized in that: The first positive lens has a light-transmitting aperture of 6.1 mm, a thickness of 3.5 mm, a first surface radius of curvature of 32.5 mm, and a second surface radius of curvature of -5.4 mm. The first negative lens has a light-transmitting aperture of 6.0 mm, a thickness of 1.5 mm, a first surface radius of curvature of -5.4 mm, and a second surface radius of curvature of -19.2 mm. The second negative lens has a light-transmitting aperture of 6.1 mm, a thickness of 1.5 mm, a first surface radius of curvature of -33.1 mm, and a second surface radius of curvature of 8.5 mm. The third negative lens has a light-transmitting aperture of 6.4 mm, a thickness of 1.5 mm, a first surface radius of curvature of 11.9 mm, and a second surface radius of curvature of 3.1 mm. The second positive lens has a light-transmitting aperture of 6.8 mm, a thickness of 4.2 mm, a first surface radius of curvature of 6.1 mm, and a second surface radius of curvature of -5.7 mm. The third positive lens has a light-transmitting aperture of 6.6 mm, a thickness of 2.6 mm, a first surface radius of curvature of 36.1 mm, and a second surface radius of curvature of 208.7 mm.

3. The shortwave infrared hyperspectral telescope head as described in claim 1, characterized in that: The first positive lens and the first negative lens together form a cemented lens.

4. The shortwave infrared hyperspectral telescope head as described in claim 1, characterized in that: The distance between the center of the light-emitting surface of the third positive lens and the image plane is 8.0 mm.

5. The shortwave infrared hyperspectral telescope head as described in claim 1, characterized in that: The optical dimensions are φ6.8×19.25mm.

6. The shortwave infrared hyperspectral telescope head as described in claim 1, characterized in that: The focal length is 13.94mm and the F-number is 2.

3.

7. The shortwave infrared hyperspectral telescope head as described in claim 1, characterized in that: The operating wavelength range is 1000nm~2500nm.

8. The shortwave infrared hyperspectral telescope head as described in claim 1, characterized in that: Full field of view 12°.

9. The shortwave infrared hyperspectral telescope head as described in claim 1, characterized in that: The principal rays in each field of view are perpendicular to the image plane.

Images