Compact co-aperture three-waveband infrared optical system

Abstract

This invention discloses a compact common-aperture three-band infrared optical system, comprising an infrared optical system body, a short-wave infrared imaging component, a mid-wave infrared imaging component, and a long-wave infrared imaging component. The infrared optical system body is sequentially arranged along the light incident direction with a Cassegrain afocal system, a secondary beam-shrinking structure, a first dichroic mirror, a second dichroic mirror, a short-wave infrared imaging component, a mid-wave infrared imaging component, and a long-wave infrared imaging component. All imaging components on the infrared optical system body are arranged in the axial space behind the primary mirror. The two dichroic separations achieve optical path separation, eliminating the need for complex folding and reflection structures, significantly reducing volume and weight, providing strong adaptability, simple processing and assembly, all-weather multi-feature detection, and simultaneously acquiring reflection features, high-temperature features, and room-temperature thermal radiation features, thereby improving target recognition rate.

Description

Technical Field

[0001] This invention relates to the field of optical imaging technology, specifically to a compact common aperture three-band infrared optical system. Background Technology

[0002] With the rapid development of photoelectric detection technology, single-band imaging systems are no longer sufficient to meet the demands of target identification and precise detection in complex environments. Infrared imaging offers advantages such as good concealment, independence from lighting conditions, and all-weather operation. However, different infrared sub-bands reflect different target characteristics: short-wave infrared primarily reflects the target's reflectivity, resulting in high image contrast; mid-wave infrared is sensitive to high-temperature targets and has strong smoke penetration capabilities; long-wave infrared has strong thermal radiation detection capabilities for targets at normal temperatures, making it suitable for observing detailed temperature distribution. Fusion imaging using short-wave, mid-wave, and long-wave infrared bands can significantly improve target detection and identification capabilities.

[0003] Existing multi-band infrared detection systems typically employ three independent optical systems combined via mechanical structures, resulting in problems such as large size, heavy weight, and dispersed layout. Furthermore, the spatial consistency of multi-band images is poor, hindering image fusion processing. Simultaneously, compact optical systems capable of simultaneously covering short-wave, mid-wave, and long-wave bands and achieving co-aperture integration are lacking. Therefore, there is an urgent need for a more compact, rationally laid-out, and high-quality three-band infrared co-aperture optical system. Consequently, an improved technology is urgently needed to address these issues present in existing technologies. Summary of the Invention

[0004] The purpose of this invention is to provide a compact, common-aperture, three-band infrared optical system that provides an imaging component arranged in the axial space behind the primary mirror, achieves optical path separation through two color separations, eliminates the need for complex folding and reflection structures, significantly reduces volume and weight, has strong adaptability, is easy to process and assemble, and enables all-weather multi-feature detection: simultaneously acquiring reflection features, high-temperature features, and room-temperature thermal radiation features, thereby improving target recognition rate. This system aims to solve the problems mentioned in the background art.

[0005] To achieve the above objectives, the present invention provides the following technical solution: a compact common aperture three-band infrared optical system, comprising an infrared optical system body, a short-wave infrared imaging component, a mid-wave infrared imaging component, and a long-wave infrared imaging component. The infrared optical system body is provided with the following components sequentially along the incident direction of light: a Cassegrain afocal system, a secondary beam-shrinking structure, a first dichroic mirror, a second dichroic mirror, a short-wave infrared imaging component, a mid-wave infrared imaging component, and a long-wave infrared imaging component. The Cassegrain afocal system includes a primary mirror and a secondary mirror. The primary mirror is a parabolic reflector with a central aperture, and the secondary mirror is a parabolic reflector used to collect short-wave, mid-wave, and long-wave infrared radiation. The secondary beam-shrinking structure is located in the optical path on the back of the primary mirror, behind the Cassegrain afocal system. The first dichroic mirror is used to transmit long-wave infrared beams and reflect mixed short-wave infrared and mid-wave infrared beams; The second dichroic mirror is disposed in the reflective optical path of the first dichroic mirror and is used to transmit short-wave infrared beams and reflect mid-wave infrared beams; The short-wave infrared imaging component, mid-wave infrared imaging component, and long-wave infrared imaging component respectively receive beams of their respective wavelength bands. Except for the primary and secondary mirrors of the Cassegrain afocal system, which have parabolic aspherical structures, all other mirrors in the system have spherical structures.

[0006] Preferably, the secondary beam-shrinking structure includes, in sequence along the optical path: a secondary beam-shrinking first lens, a secondary beam-shrinking first cemented lens, a secondary beam-shrinking second lens, and a secondary beam-shrinking third lens.

[0007] Preferably, the shortwave infrared imaging component includes, in sequence along the optical path, a first shortwave infrared lens, a second shortwave infrared lens, a third shortwave infrared lens, a fourth shortwave infrared lens, and a fifth shortwave infrared lens.

[0008] Preferably, the mid-wave infrared imaging component includes a mid-wave infrared first lens, a mid-wave infrared second lens, a mid-wave infrared third lens, and a mid-wave infrared fourth lens arranged sequentially along the optical path.

[0009] Preferably, the long-wave infrared imaging component includes a long-wave infrared first lens, a long-wave infrared second lens, a long-wave infrared third lens, and a long-wave infrared fourth lens arranged sequentially along the optical path.

[0010] Preferably, the short-wave infrared imaging component, the mid-wave infrared imaging component, and the long-wave infrared imaging component are all arranged in the back axial space of the Cassegrain afocal system primary mirror.

[0011] Compared with the prior art, the beneficial effects of the present invention are: All imaging components on the main body of this infrared optical system are arranged in the axial space on the back of the primary mirror. The optical path is separated by two color separations, eliminating the need for complex folding and reflection structures, significantly reducing the size and weight. It has strong adaptability, is simple to process and assemble, and can detect multiple features in all weather conditions. It can simultaneously acquire reflection features, high temperature features, and room temperature thermal radiation features, thereby improving the target recognition rate. Attached Figure Description

[0012] Figure 1 This is a schematic diagram of the overall structure of the compact common aperture three-band infrared optical system of the present invention; Figure 2 This is a schematic diagram of the common aperture optical antenna structure of the present invention; Figure 3 This is a schematic diagram of the shortwave infrared imaging component structure of the present invention; Figure 4 This is a schematic diagram of the mid-wave infrared imaging component structure of the present invention; Figure 5 This is a schematic diagram of the structure of the long-wave infrared imaging component of the present invention.

[0013] In the diagram: 1. Primary lens of the Cassette afocal system; 2. Secondary lens of the Cassette afocal system; 3. Secondary beam-shrinking first lens; 4. Secondary beam-shrinking first cemented lens; 5. Secondary beam-shrinking second lens; 6. Secondary beam-shrinking third lens; 7. First short-wave infrared lens; 8. Second short-wave infrared lens; 9. Third short-wave infrared lens; 10. Fourth short-wave infrared lens; 11. Fifth short-wave infrared lens; 12. First mid-wave infrared lens; 13. Second mid-wave infrared lens; 14. Third mid-wave infrared lens; 15. Fourth mid-wave infrared lens; 16. First long-wave infrared lens; 17. Second long-wave infrared lens; 18. Third long-wave infrared lens; 19. Fourth long-wave infrared lens; 20. Infrared optical system body; 21. Short-wave infrared imaging component; 22. Mid-wave infrared imaging component; 23. Long-wave infrared imaging component. Detailed Implementation

[0014] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. 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 are within the scope of protection of the present invention.

[0015] Please see Figures 1-5 The present invention provides a technical solution: a compact common aperture three-band infrared optical system, comprising an infrared optical system body 20, a short-wave infrared imaging component 21, a mid-wave infrared imaging component 22, and a long-wave infrared imaging component 23. The infrared optical system body 20 is provided with the following components in sequence along the incident direction of light: a Cassegrain afocal system, a secondary beam-shrinking structure, a first dichroic mirror, a second dichroic mirror, the short-wave infrared imaging component 21, the mid-wave infrared imaging component 22, and the long-wave infrared imaging component 23.

[0016] The secondary beam-shrinking structure includes, in sequence along the optical path: a secondary beam-shrinking first lens 3, a secondary beam-shrinking first cemented lens 4, a secondary beam-shrinking second lens 5, and a secondary beam-shrinking third lens 6.

[0017] The shortwave infrared imaging component 24 includes the following components arranged sequentially along the optical path: a shortwave infrared first lens 7, a shortwave infrared second lens 8, a shortwave infrared third lens 9, a shortwave infrared fourth lens 10, and a shortwave infrared fifth lens 11. The shortwave infrared imaging component 21, the midwave infrared imaging component 22, and the longwave infrared imaging component 23 are all arranged in the axial space behind the primary mirror of the Cassegrain afocal system.

[0018] The mid-wave infrared imaging component 22 includes a mid-wave infrared first lens 12, a mid-wave infrared second lens 13, a mid-wave infrared third lens 14, and a mid-wave infrared fourth lens 15 arranged sequentially along the optical path.

[0019] The long-wave infrared imaging component 23 includes a long-wave infrared first lens 16, a long-wave infrared second lens 17, a long-wave infrared third lens 18, and a long-wave infrared fourth lens 19 arranged sequentially along the optical path.

[0020] The Cassegrain afocal system includes a Cassegrain afocal system primary mirror 1 and a Cassegrain afocal system secondary mirror 2. The Cassegrain afocal system primary mirror 1 is a parabolic reflector with a light-passing aperture in the center. The Cassegrain afocal system secondary mirror 2 is a parabolic reflector used to collect short-wave, mid-wave, and long-wave infrared radiation across the entire spectrum. The front end of the system shares the Cassegrain afocal system, achieving common-aperture collection of short-wave, mid-wave, and long-wave infrared radiation, ensuring spatial consistency of multi-band images, and facilitating fusion.

[0021] The secondary beam-shrinking structure is located in the optical path on the back of the primary mirror, behind the Cassegrain afocal system. The first dichroic mirror is used to transmit long-wave infrared beams and reflect mixed short-wave and mid-wave infrared beams.

[0022] The second dichroic mirror is placed in the reflective optical path of the first dichroic mirror and is used to transmit short-wave infrared beams and reflect mid-wave infrared beams.

[0023] The short-wave infrared imaging component 21, the mid-wave infrared imaging component 22, and the long-wave infrared imaging component 23 respectively receive beams of their respective bands. Except for the primary and secondary mirrors of the Cassegrain afocal system, which adopt parabolic aspherical structures, all other mirrors adopt spherical structures.

[0024] Example 1 A compact common aperture three-band infrared optical system includes an infrared optical system body 20, a short-wave infrared imaging component 21, a mid-wave infrared imaging component 22, and a long-wave infrared imaging component 23. The entire system is arranged along the incident direction of light by a Cassegrain afocal system, a secondary beam-shrinking structure, a first dichroic mirror, a second dichroic mirror, and imaging components for each band.

[0025] Cassegrain Focusless System The Cassegrain afocal system consists of a primary mirror 1 and a secondary mirror 2. The primary mirror 1 is a parabolic reflector with a central aperture for transmitting the full-band infrared beam reflected by the secondary mirror 2. The secondary mirror 2 is also a parabolic reflector, which, together with the primary mirror 1, forms an afocal optical path. This allows for the common-aperture collection and collimation of the target's short-wave infrared, mid-wave infrared, and long-wave infrared radiation, ensuring that the incident light paths for the three bands are completely consistent.

[0026] The secondary beam-shrinking structure is located in the optical path on the back of the primary mirror 1, behind the Cassegrain afocal system. Along the optical path, it includes a secondary beam-shrinking first lens 3, a secondary beam-shrinking first cemented lens 4, a secondary beam-shrinking second lens 5, and a secondary beam-shrinking third lens 6. This structure performs beam-shrinking and aberration correction on the parallel beam output from the afocal system, compressing the large-aperture beam into a small-aperture beam suitable for subsequent imaging components, optimizing the optical path aperture and overall length, and providing a basis for system miniaturization.

[0027] The beam, after being reduced to a single beam size, is incident on the first dichroic mirror: The first dichroic mirror transmits a long-wave infrared beam, which directly enters the long-wave infrared imaging component 23.

[0028] The first dichroic mirror reflects a mixed beam of short-wave infrared and mid-wave infrared light, guiding it to the second dichroic mirror.

[0029] The mixed beam is further separated after being incident on the second dichroic mirror: The second dichroic mirror transmits a short-wave infrared beam, which enters the short-wave infrared imaging component 21. The second dichroic mirror reflects the mid-wave infrared beam, which then enters the mid-wave infrared imaging component 22.

[0030] By performing two beam splits, independent imaging of the short-wave, medium-wave, and long-wave bands is achieved. Moreover, all beam splitting elements are planar elements, without introducing additional complex curved surfaces, resulting in a simple and reliable structure.

[0031] Imaging components for each band The shortwave infrared imaging component 21 is provided with a first shortwave infrared lens 7, a second lens 8, a third lens 9, a fourth lens 10, and a fifth lens 11 along the optical path to focus and image the shortwave infrared beam and obtain a high-contrast reflection feature image of the target.

[0032] The mid-wave infrared imaging component 22 is equipped with a first mid-wave infrared lens 12, a second lens 13, a third lens 14, and a fourth lens 15 along the optical path to complete mid-wave infrared beam imaging and effectively detect high-temperature targets and smoke-penetrating scenes.

[0033] The long-wave infrared imaging component 23 is provided with a first long-wave infrared lens 16, a second lens 17, a third lens 18, and a fourth lens 19 along the optical path to achieve clear imaging of the thermal radiation of a target at room temperature and output detailed information on temperature distribution.

[0034] The short-wave infrared imaging component 21, the mid-wave infrared imaging component 22, and the long-wave infrared imaging component 23 are all arranged in the axial space behind the primary mirror 1 of the cassette afocal system, making full use of the unused space behind the primary mirror without increasing the radial dimension of the system. At the same time, the folding mirror assembly and mechanical splicing structure of the traditional multi-band system are eliminated, which significantly reduces the overall size and weight of the system.

[0035] All mirrors and lenses in the system adopt a spherical structure. Compared with aspherical components, the processing technology is mature, the testing is convenient, and the assembly and adjustment are less difficult. This can effectively improve the system yield and environmental stability, making it suitable for engineering mass production.

[0036] In this embodiment, the full-band infrared radiation emitted by the target is collected by the Cassegrain afocal system through a common aperture. After secondary beam contraction, it is separated into three independent imaging optical paths—short-wave, mid-wave, and long-wave—by two-stage dichroic mirrors. Finally, the corresponding imaging components output three-channel infrared images. The three images have high spatial consistency and can be directly fused, enabling all-weather, multi-feature, and high-precision target detection and identification.

[0037] All imaging components on the main body 20 of the infrared optical system are arranged in the axial space on the back of the primary mirror. The light path is separated by two color separations, eliminating the need for a complex folding and reflection structure, significantly reducing the size and weight. It has strong adaptability, simple processing and assembly, and all-weather multi-feature detection: it can simultaneously acquire reflection features, high temperature features, and room temperature thermal radiation features, thereby improving the target recognition rate.

[0038] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A compact common-aperture three-band infrared optical system, comprising an infrared optical system body (20), a short-wave infrared imaging component (21), a mid-wave infrared imaging component (22), and a long-wave infrared imaging component (23), characterized in that: The infrared optical system body (20) is provided with the following components in sequence along the incident direction of light: Cassegrain afocal system, secondary beam-shrinking structure, first dichroic mirror, second dichroic mirror, short-wave infrared imaging component (21), mid-wave infrared imaging component (22), and long-wave infrared imaging component (23). The Cassegrain afocal system includes a Cassegrain afocal system primary mirror (1) and a Cassegrain afocal system secondary mirror (2). The Cassegrain afocal system primary mirror (1) is a parabolic reflector with a light-passing hole in the center. The Cassegrain afocal system secondary mirror (2) is a parabolic reflector used to collect short-wave, medium-wave, and long-wave infrared radiation. The secondary beam-shrinking structure is located in the optical path on the back of the primary mirror, behind the Cassegrain afocal system. The first dichroic mirror is used to transmit long-wave infrared beams and reflect mixed short-wave infrared and mid-wave infrared beams; The second dichroic mirror is disposed in the reflective optical path of the first dichroic mirror and is used to transmit short-wave infrared beams and reflect mid-wave infrared beams; The short-wave infrared imaging component (21), the mid-wave infrared imaging component (22), and the long-wave infrared imaging component (23) respectively receive beams of their respective wavelength bands. Except for the primary and secondary mirrors of the Cassegrain afocal system, which have parabolic aspherical structures, all other mirrors in the system have spherical structures.

2. The compact common-aperture three-band infrared optical system according to claim 1, characterized in that: The secondary beam-shrinking structure includes, in sequence along the optical path: a secondary beam-shrinking first lens (3), a secondary beam-shrinking first cemented lens (4), a secondary beam-shrinking second lens (5), and a secondary beam-shrinking third lens (6).

3. A compact common-aperture three-band infrared optical system according to claim 1, characterized in that: The shortwave infrared imaging component (21) includes the following components arranged sequentially along the optical path: a shortwave infrared first lens (7), a shortwave infrared second lens (8), a shortwave infrared third lens (9), a shortwave infrared fourth lens (10), and a shortwave infrared fifth lens (11).

4. A compact common-aperture three-band infrared optical system according to claim 1, characterized in that: The mid-wave infrared imaging component (22) includes a mid-wave infrared first lens (12), a mid-wave infrared second lens (13), a mid-wave infrared third lens (14), and a mid-wave infrared fourth lens (15) arranged sequentially along the optical path.

5. A compact common-aperture three-band infrared optical system according to claim 1, characterized in that: The long-wave infrared imaging component (23) includes a long-wave infrared first lens (16), a long-wave infrared second lens (17), a long-wave infrared third lens (18), and a long-wave infrared fourth lens (19) arranged sequentially along the optical path.

6. A compact common-aperture three-band infrared optical system according to claim 1, characterized in that: The short-wave infrared imaging component (21), the mid-wave infrared imaging component (22), and the long-wave infrared imaging component (23) are all arranged in the back axial space of the Cassegrain afocal system primary mirror.

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