A mid-wave infrared and long-wave infrared multispectral imaging system

Abstract

This invention discloses a mid-wave infrared and long-wave infrared multispectral imaging system, belonging to the field of mid-wave infrared and long-wave infrared multispectral imaging. It includes a beam splitter for separating the incident beam, a long-wave infrared multispectral imaging system arranged along the transmission path of the beam splitter, and a mid-wave infrared multispectral imaging system arranged along the reflection path of the beam splitter. The long-wave infrared multispectral imaging system, arranged sequentially along the optical path, comprises a beam splitter, four long-wave infrared refractors, a long-wave infrared multispectral filter, a long-wave infrared detector window, a long-wave infrared detector cold stop, and a long-wave infrared detector imaging surface. The mid-wave infrared multispectral imaging system, arranged sequentially along the optical path, comprises a beam splitter, a mid-wave infrared reflector, six mid-wave infrared refractors, a mid-wave infrared multispectral filter, a mid-wave infrared detector window, a mid-wave infrared detector cold stop, and a mid-wave infrared detector imaging surface. This invention achieves miniaturization of the filters through a reasonable filter layout design, effectively improving the system's compactness.

Description

Technical Field

[0001] This invention belongs to the field of mid-wave infrared and long-wave infrared multispectral imaging, and specifically relates to a mid-wave infrared and long-wave infrared multispectral imaging system. Background Technology

[0002] To achieve all-weather target scene detection and more accurate target detection and identification, imaging systems need to possess multispectral information acquisition capabilities. Mid-wave infrared and long-wave infrared imaging utilize the radiation characteristics of targets and scenes, providing all-weather imaging capabilities. By further subdividing the mid-wave infrared and long-wave infrared spectra, spectral information of target scenes can be acquired more accurately, thereby improving target recognition capabilities.

[0003] Due to significant differences in wavelengths and limitations imposed by the detector's operating wavelength, mid-wave infrared and long-wave infrared imaging systems typically use independent imaging optical paths for detection and imaging. However, long-range target detection systems are characterized by large imaging apertures and long focal lengths. To achieve system compactness, long-range imaging systems often employ a shared telescope array and two independent converging imaging optical paths for each wavelength band. Because of the relatively complex optical path composition, achieving miniaturization and high-sensitivity detection capabilities requires a compact and high-transmittance design for the converging imaging optical path.

[0004] The mid-wave infrared and long-wave infrared bands have a wide range, and there are fewer choices of infrared optical materials, making it difficult to correct aberrations in imaging systems. Usually, it is necessary to increase the number of optical lenses and aspherical surfaces to ensure better imaging quality. However, increasing the number of optical lenses reduces the transmittance of the imaging system, which is not conducive to the detection of distant targets. Increasing the number of aspherical surfaces increases the processing and assembly difficulty of optical components, which is not conducive to the engineering application of imaging systems.

[0005] Multispectral imaging systems require the addition of filter elements with different spectral ranges in the imaging optical path to acquire information on different spectral bands of the target scene. The size of the filter element directly determines the size of the multispectral switching mechanism, so the size of the filter element in a multispectral imaging system needs to be designed to be small. Summary of the Invention

[0006] The technical problem to be solved:

[0007] To overcome the shortcomings of existing technologies, this invention provides a mid-wave infrared and long-wave infrared multispectral imaging system. Based on optimized aberration allocation and a reasonable combination of optical materials, it utilizes four long-wave infrared lenses to achieve long-wave infrared converging imaging and six mid-wave infrared lenses to achieve mid-wave infrared converging imaging. Furthermore, only three aspherical surfaces are used in the mid-wave infrared and long-wave infrared optical paths, resulting in excellent fabrication and assembly adaptability. Through a rational filter layout design, this invention achieves miniaturized filter design, effectively improving the system's compactness.

[0008] The technical solution of the present invention is: a mid-wave infrared and long-wave infrared multispectral imaging system, comprising a beam splitter 1 for separating incident beams, a long-wave infrared multispectral imaging system arranged along the transmission light path of the beam splitter, and a mid-wave infrared multispectral imaging system arranged along the reflection light path of the beam splitter.

[0009] The long-wave infrared multispectral imaging system is provided with a beam splitter 1, a first long-wave infrared refracting mirror 2, a second long-wave infrared refracting mirror 3, a third long-wave infrared refracting mirror 4, a fourth long-wave infrared refracting mirror 5, a long-wave infrared multispectral filter 6, a long-wave infrared detector window 7, a long-wave infrared detector cold aperture 8, and a long-wave infrared detector imaging surface 9 along the optical path.

[0010] The mid-wave infrared multispectral imaging system is provided with the following components along the optical path: a beam splitter 1, a mid-wave infrared reflector 10, a first mid-wave infrared refractor 11, a second mid-wave infrared refractor 12, a third mid-wave infrared refractor 13, a fourth mid-wave infrared refractor 14, a fifth mid-wave infrared refractor 15, a sixth mid-wave infrared refractor 16, a mid-wave infrared multispectral filter 17, a mid-wave infrared detector window 18, a mid-wave infrared detector cold aperture 19, and a mid-wave infrared detector imaging surface 20.

[0011] A further technical solution of the present invention is as follows: the beam splitter 1 is a plane mirror, the mid-wave infrared reflector 10 is a plane reflector, the long-wave infrared multispectral filter 6 and the mid-wave infrared multispectral filter 17 are plane mirrors, the first long-wave infrared refractor 2, the third long-wave infrared refractor 4, the first mid-wave infrared refractor 11, the third mid-wave infrared refractor 13, the fourth mid-wave infrared refractor 14 and the sixth mid-wave infrared refractor 16 are convex lenses, and the second long-wave infrared refractor 3, the fourth long-wave infrared refractor 5, the second mid-wave infrared refractor 12 and the fifth mid-wave infrared refractor 15 are concave lenses.

[0012] A further technical solution of the present invention is that the rear surface of the first long-wave infrared refractor 2, the front surface of the second long-wave infrared refractor 3, the rear surface of the third long-wave infrared refractor 4, the rear surface of the first medium-wave infrared refractor 11, the rear surface of the second medium-wave infrared refractor 12, and the rear surface of the fourth medium-wave infrared refractor 14 are aspherical, while the other surfaces are spherical.

[0013] A further technical solution of the present invention is: the front surface of the beam splitter 1 along the incident direction is provided with a beam splitting film layer with a reflection band range of 3.7 to 4.8 μm and a transmission band range of 8 to 12.5 μm.

[0014] A further technical solution of the present invention is as follows: the rear surface of the beam splitter 1, the first long-wave infrared refractor 2, the second long-wave infrared refractor 3, the third long-wave infrared refractor 4, and the fourth long-wave infrared refractor 5 are provided with a material having a transmission band range of 8 to 12.5 μm; the surface of the long-wave infrared multispectral filter 6 is provided with a beam splitting band within any range of 8 to 12.5 μm; the surface of the mid-wave infrared reflector 10, the first mid-wave infrared refractor 11, the second mid-wave infrared refractor 12, the third mid-wave infrared refractor 13, the fourth mid-wave infrared refractor 14, the fifth mid-wave infrared refractor 15, and the sixth mid-wave infrared refractor 16 is provided with a material having a transmission band range of 3.7 to 4.8 μm; and the surface of the mid-wave infrared multispectral filter 17 is provided with a beam splitting band within any range of 3.7 to 4.8 μm.

[0015] A further technical solution of the present invention is: the optical parameters of the mid-wave infrared multispectral imaging system are,

[0016]

[0017] A further technical solution of the present invention is: the mid-wave infrared multispectral filter is provided with filters of different wavelength ranges, and multispectral detection is achieved by switching them.

[0018] A further technical solution of the present invention is: the optical parameters of the long-wave infrared multispectral imaging system are,

[0019]

[0020] A further technical solution of the present invention is: the long-wave infrared multispectral filter is provided with filters of different wavelength ranges, and multispectral detection is achieved by switching them.

[0021] A further technical solution of the present invention is as follows: the materials on the beam splitter 1, the first long-wave infrared refractor 2, the second long-wave infrared refractor 3, the third long-wave infrared refractor 4, the second mid-wave infrared refractor 12, the fifth mid-wave infrared refractor 15, the long-wave infrared multispectral filter 6, and the mid-wave infrared multispectral filter 17 are single-crystal germanium; the materials on the first mid-wave infrared refractor 11, the third mid-wave infrared refractor 13, the fourth mid-wave infrared refractor 14, and the sixth mid-wave infrared refractor 16 are single-crystal silicon; and the material on the fourth long-wave infrared refractor 5 is zinc selenide.

[0022] Beneficial effects

[0023] The beneficial effects of this invention are as follows: This invention provides a high-transmittance, compact mid-wave infrared and long-wave infrared multispectral imaging system with operating wavelengths of 3.7–4.8 μm and 8–12.5 μm. Specifically, a beam splitter separates the mid-wave infrared and long-wave infrared bands, a mid-wave infrared reflector makes the imaging system more compact, and the long-wave infrared multispectral filter and mid-wave infrared multispectral filter can achieve multispectral imaging by switching multiple filters.

[0024] This invention achieves a compact and high-transmittance design for mid-wave infrared and long-wave infrared multispectral imaging systems by rationally combining optical materials in the imaging system, rationally allocating aberration compensation for each optical element, and rationally designing the filter layout to reduce the size of the filters. Attached Figure Description

[0025] Figure 1 This is a structural diagram of the high transmittance, compact mid-wave infrared and long-wave infrared multispectral imaging system of the present invention.

[0026] Explanation of reference numerals in the attached diagram: 1. Beam splitter; 2. First long-wave infrared refractor; 3. Second long-wave infrared refractor; 4. Third long-wave infrared refractor; 5. Fourth long-wave infrared refractor; 6. Long-wave infrared multispectral filter; 7. Long-wave infrared detector window; 8. Long-wave infrared detector cold stop; 9. Long-wave infrared detector imaging surface; 10. Mid-wave infrared reflector; 11. First mid-wave infrared refractor; 12. Second mid-wave infrared refractor; 13. Third mid-wave infrared refractor; 14. Fourth mid-wave infrared refractor; 15. Fifth mid-wave infrared refractor; 16. Sixth mid-wave infrared refractor; 17. Mid-wave infrared multispectral filter; 18. Mid-wave infrared detector window; 19. Mid-wave infrared detector cold stop; 20. Mid-wave infrared detector imaging surface. Detailed Implementation

[0027] The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain the invention, and should not be construed as limiting the invention.

[0028] In existing technologies, mid-wave infrared and long-wave infrared imaging systems typically use independent imaging optical paths for detection and imaging. However, long-range target detection systems are characterized by large imaging apertures and long focal lengths. To achieve a compact imaging system, long-range imaging systems often employ a shared telescope group and two independent converging imaging optical paths for each band, resulting in problems such as large size and low light transmittance. This invention provides a mid-wave infrared and long-wave infrared multispectral imaging system, comprising a beam splitter 1 for separating the incident beam, a long-wave infrared multispectral imaging system arranged along the transmission optical path of the beam splitter, and a mid-wave infrared multispectral imaging system arranged along the reflection optical path of the beam splitter. The long-wave infrared multispectral imaging system has the following components arranged sequentially along the optical axis of the incident direction: beam splitter 1, first long-wave infrared refractor 2, second long-wave infrared refractor 3, third long-wave infrared refractor 4, fourth long-wave infrared refractor 5, long-wave infrared multispectral filter 6, long-wave infrared detector window 7, and long-wave infrared... The external detector has a cold aperture 8 and a long-wave infrared detector imaging surface 9. The mid-wave infrared multispectral imaging system is provided with a beam splitter 1, a mid-wave infrared reflector 10, a first mid-wave infrared refractor 11, a second mid-wave infrared refractor 12, a third mid-wave infrared refractor 13, a fourth mid-wave infrared refractor 14, a fifth mid-wave infrared refractor 15, a sixth mid-wave infrared refractor 16, a mid-wave infrared multispectral filter 17, a mid-wave infrared detector window 18, a mid-wave infrared detector cold aperture 19, and a mid-wave infrared detector imaging surface 20 along the optical axis of the incident direction.

[0029] The beam splitter 1 separates the mid-wave infrared and long-wave infrared bands, the mid-wave infrared reflector 10 makes the imaging system more compact, and the long-wave infrared multispectral filter 6 and the mid-wave infrared multispectral filter 17 can achieve multispectral imaging by switching multiple filters, resulting in a high-transmittance, compact mid-wave infrared and long-wave infrared multispectral imaging system.

[0030] Specifically, beam splitter 1 is a plane mirror, mid-wave infrared reflector 10 is a plane reflector, long-wave infrared multispectral filter 6 and mid-wave infrared multispectral filter 17 are plane mirrors, first long-wave infrared refractor 2, third long-wave infrared refractor 4, first mid-wave infrared refractor 11, third mid-wave infrared refractor 13, fourth mid-wave infrared refractor 14 and sixth mid-wave infrared refractor 16 are convex lenses, and second long-wave infrared refractor 3, fourth long-wave infrared refractor 5, second mid-wave infrared refractor 12 and fifth mid-wave infrared refractor 15 are concave lenses. The rear surface of first long-wave infrared refractor 2, the front surface of second long-wave infrared refractor 3, the rear surface of third long-wave infrared refractor 4, the rear surface of first mid-wave infrared refractor 11, the rear surface of second mid-wave infrared refractor 12 and the rear surface of fourth mid-wave infrared refractor 14 are aspherical surfaces, and all other surfaces are spherical surfaces.

[0031] Specifically, the front surface of the beam splitter 1 along the incident direction is provided with a beam-splitting film layer with a reflection band range of 3.7–4.8 μm and a transmission band range of 8–12.5 μm. The rear surface of the beam splitter 1, the first long-wave infrared refractor 2, the second long-wave infrared refractor 3, the third long-wave infrared refractor 4, and the fourth long-wave infrared refractor 5 are provided with a material with a transmission band range of 8–12.5 μm. The long-wave infrared multispectral filter 6 is provided with a beam-splitting band within any range of 8–12.5 μm. The mid-wave infrared reflector 10, the first mid-wave infrared refractor 11, the second mid-wave infrared refractor 12, the third mid-wave infrared refractor 13, the fourth mid-wave infrared refractor 14, the fifth mid-wave infrared refractor 15, and the sixth mid-wave infrared refractor 16 are provided with a material with a transmission band range of 3.7–4.8 μm. The mid-wave infrared multispectral filter 17 is provided with a beam-splitting band within any range of 3.7–4.8 μm.

[0032] Beam splitter 1 separates the mid-wave infrared and long-wave infrared bands, the mid-wave infrared reflector makes the imaging system more compact, and the long-wave infrared multispectral filter and the mid-wave infrared multispectral filter can achieve multispectral imaging by switching multiple filters respectively.

[0033] The mid-wave infrared reflector makes the mid-wave infrared imaging optical path more compact. The reflector material can be glass, crystal, metal, semiconductor, or composite material. The materials on beam splitter 1, first long-wave infrared refractor 2, second long-wave infrared refractor 3, third long-wave infrared refractor 4, second mid-wave infrared refractor 12, fifth mid-wave infrared refractor 15, long-wave infrared multispectral filter 6, and mid-wave infrared multispectral filter 17 are made of single-crystal germanium. The materials on first mid-wave infrared refractor 11, third mid-wave infrared refractor 13, fourth mid-wave infrared refractor 14, and sixth mid-wave infrared refractor 16 are made of single-crystal silicon. The material on fourth long-wave infrared refractor 5 is zinc selenide.

[0034] Specifically, the parameters such as the mid-wave infrared curvature radius and thickness of the lens are shown in Table 1, and the parameters such as the long-wave infrared curvature radius and thickness are shown in Table 2.

[0035] Table 1

[0036]

[0037]

[0038] Table 2

[0039]

[0040]

[0041]

[0042] The objectives achievable by this invention are as follows: the working band for mid-wave infrared is 3.7–4.8 μm, and the working band for long-wave infrared is 8–12.5 μm. The focal length of both mid-wave infrared and long-wave infrared multispectral imaging systems is 62.5 mm, the imaging aperture is 25 mm, the F-number of both imaging systems is 2.5, the imaging field of view is 12°, and the multispectral filter size is 21 mm. Multispectral detection can be achieved by switching filters of different bands. The transmittance of both mid-wave infrared and long-wave infrared imaging systems can reach above 0.90.

[0043] Although embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those skilled in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of the present invention without departing from the principles and spirit of the present invention.

Claims

1. A mid-wave infrared and long-wave infrared multispectral imaging system, characterized in that: Includes a beam splitter (1) that separates the incident beam, a long-wave infrared multispectral imaging system set along the transmission light path of the beam splitter, and a mid-wave infrared multispectral imaging system set along the reflection light path of the beam splitter; The long-wave infrared multispectral imaging system is provided with a beam splitter (1), a first long-wave infrared refracting mirror (2), a second long-wave infrared refracting mirror (3), a third long-wave infrared refracting mirror (4), a fourth long-wave infrared refracting mirror (5), a long-wave infrared multispectral filter (6), a long-wave infrared detector window (7), a long-wave infrared detector cold aperture (8), and a long-wave infrared detector imaging surface (9) in sequence along the optical path. The mid-wave infrared multispectral imaging system is provided with the following components along the optical path: a beam splitter (1), a mid-wave infrared reflector (10), a first mid-wave infrared refractor (11), a second mid-wave infrared refractor (12), a third mid-wave infrared refractor (13), a fourth mid-wave infrared refractor (14), a fifth mid-wave infrared refractor (15), a sixth mid-wave infrared refractor (16), a mid-wave infrared multispectral filter (17), a mid-wave infrared detector window (18), a mid-wave infrared detector cold aperture (19), and a mid-wave infrared detector imaging surface (20). The beam splitter (1) is a plane mirror, the mid-wave infrared reflector (10) is a plane reflector, the long-wave infrared multispectral filter (6) and the mid-wave infrared multispectral filter (17) are plane mirrors, the first long-wave infrared refractor (2), the third long-wave infrared refractor (4), the first mid-wave infrared refractor (11), the third mid-wave infrared refractor (13), the fourth mid-wave infrared refractor (14) and the sixth mid-wave infrared refractor (16) are convex lenses, and the second long-wave infrared refractor (3), the fourth long-wave infrared refractor (5), the second mid-wave infrared refractor (12) and the fifth mid-wave infrared refractor (15) are concave lenses; The rear surface of the first long-wave infrared refractor (2), the front surface of the second long-wave infrared refractor (3), the rear surface of the third long-wave infrared refractor (4), the rear surface of the first medium-wave infrared refractor (11), the rear surface of the second medium-wave infrared refractor (12), and the rear surface of the fourth medium-wave infrared refractor (14) are aspherical, while the other surfaces are spherical.

2. The mid-wave infrared and long-wave infrared multispectral imaging system according to claim 1, characterized in that: The beam splitter (1) has a beam splitting film layer with a reflection band range of 3.7 to 4.8 μm and a transmission band range of 8 to 12.5 μm on its front surface along the incident direction.

3. The mid-wave infrared and long-wave infrared multispectral imaging system according to claim 2, characterized in that: The back surface of the beam splitter (1), the first long-wave infrared refractor (2), the second long-wave infrared refractor (3), the third long-wave infrared refractor (4), and the fourth long-wave infrared refractor (5) are provided with materials that transmit wavelengths in the range of 8 to 12.5 μm. The long-wave infrared multispectral filter (6) is provided with filters in different wavelength ranges within 8 to 12.5 μm. The mid-wave infrared reflector (10), the first mid-wave infrared refractor (11), the second mid-wave infrared refractor (12), the third mid-wave infrared refractor (13), the fourth mid-wave infrared refractor (14), the fifth mid-wave infrared refractor (15), and the sixth mid-wave infrared refractor (16) are provided with materials that transmit wavelengths in the range of 3.7 to 4.8 μm. The mid-wave infrared multispectral filter (17) is provided with filters in different wavelength ranges within 3.7 to 4.8 μm.

4. The midwave and longwave infrared multispectral imaging system of claim 3, wherein: The mid-wave infrared multispectral filter (17) is equipped with filters of different wavelength ranges, and multispectral detection is achieved by switching the filters.

5. The midwave and longwave infrared multispectral imaging system of claim 3, wherein: The long-wave infrared multispectral filter (6) is equipped with filters of different wavelength ranges, and multispectral detection is achieved by switching the filters.

6. A mid-wave infrared and long-wave infrared multispectral imaging system according to any one of claims 3, characterized in that: The materials on the beam splitter (1), the first long-wave infrared refractor (2), the second long-wave infrared refractor (3), the third long-wave infrared refractor (4), the second mid-wave infrared refractor (12), the fifth mid-wave infrared refractor (15), the long-wave infrared multispectral filter (6), and the mid-wave infrared multispectral filter (17) are single-crystal germanium, the materials on the first mid-wave infrared refractor (11), the third mid-wave infrared refractor (13), the fourth mid-wave infrared refractor (14), and the sixth mid-wave infrared refractor (16) are single-crystal silicon, and the material on the fourth long-wave infrared refractor (5) is zinc selenide.

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