Optical system and method for implementing mid-wave infrared spectral imaging and mid-wave infrared imaging based on dyson improved concentric structure

Abstract

The present application relates to infrared optical system, specifically to the optical system and method for realizing mid-wave infrared spectral imaging and mid-wave infrared imaging based on Dyson improved concentric structure, which is used to solve the problems of large volume, complex structure and limited transmittance in the realization of existing mid-wave infrared system and mid-wave infrared spectral imaging system. The optical system for realizing mid-wave infrared spectral imaging and mid-wave infrared imaging based on Dyson improved concentric structure, by switching the switching device to a plane reflective grating or a plane mirror, using the plane reflective grating and the plane mirror, realizing the common optical path design of the mid-wave infrared spectral imaging system and the mid-wave infrared system, the optical parameters of the two systems are consistent, the transmittance is high, the switching method is simple, and the time-sharing imaging of the mid-wave infrared spectral imaging and the mid-wave infrared imaging can be realized.

Description

Technical Field

[0001] This invention relates to infrared optical systems, and more specifically to an optical system and method for realizing mid-wave infrared spectral imaging and mid-wave infrared imaging based on a Dyson improved concentric structure. Background Technology

[0002] Mid-wave infrared (MBIR) systems are a technology for detecting and imaging infrared thermal radiation, primarily receiving the infrared radiation energy emanating from the target itself. They have important applications in civilian industrial production and the medical field. In civilian industrial production, MBIR systems are used for equipment status monitoring, quality inspection, and process control. In the medical field, MBIR technology is used for lesion detection, body temperature monitoring, and intraoperative navigation.

[0003] Mid-wave infrared spectral imaging is a technique that uses multiple channels to detect and image the radiation spectrum of a target. This technique can be used not only to analyze the radiation spectrum of an object's composition but also to analyze the radiation spectrum of high-temperature objects (such as aircraft and exhaust plumes). By acquiring the spectral information of the target object, mid-wave infrared spectral imaging can provide more detailed and accurate spectral information than traditional infrared imaging.

[0004] The Dyson concentric structure is a concentric structure composed of a plano-convex lens and a concave mirror, featuring "optical path multiplexing" of the incident and outgoing beams. The beam emitted from the object point is imaged by the plano-convex lens onto the concave mirror, then reflected again by the concave mirror and imaged once more onto the image plane by the plano-convex lens. The object-image magnification is -1, and the Seidel aberration of the system approaches zero. This structure has advantages such as compact structure, small size, and light weight, and is widely used in optical systems.

[0005] Traditional mid-wave infrared (MWI) systems and MWI spectral imaging systems are generally implemented through two approaches: one is to design two separate optical systems, and the other is to use a common aperture and a semi-reflective / semi-transparent beam splitting method. While the former offers high transmittance for each optical system, it requires two independent systems, resulting in a larger size and scale. The latter, although halving the transmittance of each system through energy-based beam splitting, increases the difficulty of system design and makes the structure more complex.

[0006] In summary, existing mid-wave infrared systems and mid-wave infrared spectral imaging systems suffer from problems such as large size, complex structure, and limited transmittance during implementation. A new design scheme is urgently needed to overcome these technical bottlenecks and improve the overall performance of the system. Summary of the Invention

[0007] The purpose of this invention is to address the shortcomings of existing mid-wave infrared systems and mid-wave infrared spectral imaging systems, such as large size, complex structure, and limited transmittance, and to provide an optical system and method for realizing mid-wave infrared spectral imaging based on a Dyson improved concentric structure.

[0008] To address the shortcomings of the existing technology, the present invention provides the following technical solution:

[0009] The optical system based on the Dyson improved concentric structure for realizing mid-wave infrared spectral imaging and mid-wave infrared imaging is special in that it includes a front objective lens group, a Dyson imaging lens group, a switching device, a folding mirror and a relay lens group.

[0010] The front objective lens group is used to focus the infrared beam radiated by the target onto the primary image plane; the front objective lens group has the characteristic of telecentric pupil on the image side, including a primary reflector, a secondary reflector, a first front objective lens, and a second front objective lens arranged sequentially along the optical path; the infrared beam radiated by the target passes sequentially through the primary reflector, the secondary reflector, the central through-hole on the primary reflector, the first front objective lens, and the second front objective lens, and is then focused onto the primary image plane;

[0011] The Dyson imaging lens group is used to image the infrared beam at the primary image plane onto the secondary image plane, and uses a switching device to achieve time-division imaging of the infrared spectrum and infrared image; the Dyson imaging lens group has the characteristics of object-side and image-side telecentric pupils, including a first lens, a second lens and a third lens; the infrared beam at the primary image plane passes through the first lens, the second lens and the third lens in sequence before entering the switching device.

[0012] The switching device includes a switchable planar reflective grating and a planar reflector. The planar reflective grating is used to perform spectral splitting on the infrared beam output by the third lens and reflect it back to the third lens. The planar reflector is used to reflect the infrared beam output by the third lens back to the third lens.

[0013] The folding mirror is used to fold the outgoing imaging light path in the Dyson imaging mirror group and image it at the secondary image plane.

[0014] The relay lens group is used to image the infrared beam at the secondary image plane onto the image plane; the relay lens group has the characteristic of object-side telecentric pupil, including a fourth lens, a fifth lens, and a sixth lens arranged sequentially along the optical path; the exit pupil of the relay lens group is used to coincide with the cold screen of the infrared detector, and the image plane is used to coincide with the target surface of the infrared detector.

[0015] Furthermore, the first lens is a lens with a bending direction switching device and positive optical power, and the side away from the second lens is a high-order aspherical surface containing even-order 10; the second lens is a lens with a bending direction switching device and positive optical power, and the third lens is a lens with a bending direction switching device, containing double-sided high-order aspherical surface containing even-order 8 and negative optical power.

[0016] Furthermore, the first lens, the second lens, and the third lens are made of Ge, Si, and Ge, respectively.

[0017] Furthermore, the reflecting surface of the primary reflector is a parabolic surface with negative optical power, the reflecting surface of the secondary reflector is a hyperboloid with negative optical power, the first front objective lens is a biconvex lens with positive optical power and the incident surface is an aspheric surface containing even-order 8; the second front objective lens is a biconcave lens with negative optical power and the incident surface is an aspheric surface containing even-order 8.

[0018] Furthermore, the first front objective lens and the second front objective lens are made of ZnSe and ZnS, respectively.

[0019] Furthermore, the centerline obstruction ratio of the primary reflector and the secondary reflector is 0.35.

[0020] Furthermore, the fourth lens is a positive power lens bent towards the image plane, the fifth lens is a negative power lens bent towards the image plane containing an 8th even-order double-sided high-order aspherical surface, and the sixth lens is a positive power lens.

[0021] Furthermore, the fourth lens, the fifth lens, and the sixth lens are made of Si, Ge, and Si, respectively.

[0022] Meanwhile, this invention also provides a method for realizing mid-wave infrared spectral imaging and mid-wave infrared imaging based on a Dyson improved concentric structure, which is characterized by including the following steps:

[0023] Step 1: Construct the optical system based on the improved Dyson concentric structure to realize mid-wave infrared spectral imaging and mid-wave infrared imaging. The exit pupil of the relay lens group coincides with the cold screen of the infrared detector, and the image plane coincides with the target surface of the infrared detector.

[0024] Step 2: Switch the switching device to a planar reflective grating;

[0025] Step 3: The infrared beam radiated by the target is focused onto the primary image plane by passing it sequentially through the primary mirror, secondary mirror, first front objective lens, and second front objective lens. The infrared beam at the primary image plane then passes sequentially through the first lens, second lens, and third lens before being projected onto a planar reflective grating. The planar reflective grating performs spectral dispersion and reflection, and the beam is then focused again onto the secondary image plane by passing it through the third lens, second lens, first lens, and folding mirror, and the wavelength is spread along the dispersion direction. Finally, the beam passes sequentially through the fourth lens, fifth lens, and sixth lens to be imaged onto the image plane, thus achieving mid-wave infrared spectral imaging of the target in a wide field of view.

[0026] Step 4: Switch the switching device to a plane mirror, and move the folding mirror, relay mirror group and infrared detector as a whole away from the image plane along the optical axis of the relay mirror group to adjust the front and rear distance of the folding mirror and the propagation path of the imaging beam, so as to ensure that the infrared beam is accurately focused on the image plane.

[0027] Step 5: The infrared beam radiated by the target is focused onto the primary image plane by passing through the primary mirror, secondary mirror, first front objective lens, and second front objective lens in sequence. The infrared beam at the primary image plane passes through the first lens, second lens, and third lens in sequence before being projected onto the plane mirror. It is reflected by the plane mirror and then focused onto the secondary image plane by passing through the third lens, second lens, first lens, and folding mirror in sequence. Finally, it passes through the fourth lens, fifth lens, and sixth lens in sequence to form an image on the secondary image plane, thus achieving mid-wave infrared imaging of the target.

[0028] Compared with the prior art, the beneficial effects of the present invention are:

[0029] This invention discloses an optical system for realizing mid-wave infrared spectral imaging and mid-wave infrared imaging based on a Dyson improved concentric structure. By switching the switching device to a plane reflection grating or a plane reflection mirror, and utilizing the cut-in and cut-out plane reflection gratings and plane reflection mirrors, a common optical path design is achieved for the mid-wave infrared spectral imaging system and the mid-wave infrared system. The optical parameters of the two systems are consistent, the transmittance is high, the switching method is simple, and time-division imaging of mid-wave infrared spectral imaging and mid-wave infrared imaging can be realized. Moreover, mid-wave infrared spectral imaging breaks the limited slit field of view of traditional spectral systems and can acquire infrared spectral information under a wide field of view. It has the characteristics of simple system structure and small size. Attached Figure Description

[0030] Figure 1 This is a schematic diagram of the optical system embodiment of the present invention, which realizes mid-wave infrared spectral imaging and mid-wave infrared imaging based on the Dyson improved concentric structure;

[0031] Figure 2This is an optical path diagram for mid-wave infrared spectral imaging, based on an embodiment of the method for realizing mid-wave infrared spectral imaging and mid-wave infrared imaging using a Dyson improved concentric structure according to the present invention.

[0032] Figure 3 This is a spectral footprint map generated during mid-wave infrared spectral imaging in an embodiment of the present invention;

[0033] Figure 4 This is an optical path diagram for implementing mid-wave infrared imaging in an embodiment of the present invention.

[0034] Explanation of reference numerals in the attached figures:

[0035] 1-Front objective lens group, 101-Primary reflecting mirror, 102-Secondary reflecting mirror, 103-First front objective lens, 104-Second front objective lens;

[0036] 2-Dyson imaging lens group, 201-first lens, 202-second lens, 203-third lens;

[0037] 3-Switching device; 4-Folding reflector;

[0038] 5 - Relay lens group, 501 - Fourth lens, 502 - Fifth lens, 503 - Sixth lens;

[0039] 601 - Primary image plane, 602 - Secondary image plane, 603 - Image plane. Detailed Implementation

[0040] The present invention will be further described below with reference to the accompanying drawings and exemplary embodiments.

[0041] Reference Figure 1 An optical system for realizing mid-wave infrared spectral imaging and mid-wave infrared imaging based on a Dyson improved concentric structure includes a front objective lens group 1, a Dyson imaging lens group 2, a switching device 3, a folding mirror 4, and a relay lens group 5.

[0042] The front objective lens group 1 has a telecentric pupil on the image side, the relay lens group 5 has a telecentric pupil on the object side, and the Dyson imaging lens group 2 has a telecentric pupil on both the object side and the image side. That is, each lens group satisfies the pupil matching principle.

[0043] The front objective lens group 1 is used to focus the infrared beam radiated by the target onto the primary image plane 601. The front objective lens group 1 includes a primary reflector 101, a secondary reflector 102, a first front objective lens 103, and a second front objective lens 104 arranged sequentially along the optical path. The infrared beam radiated by the target passes sequentially through the primary reflector 101, the secondary reflector 102, the central through hole on the primary reflector 101, the first front objective lens 103, and the second front objective lens 104, and is then focused onto the primary image plane 601.

[0044] The parameters of the primary mirror 101, secondary mirror 102, first front objective lens 103, and second front objective lens 104 are shown in Table 1.

[0045] Table 1

[0046]

[0047] The primary reflector 101 has a parabolic surface with negative optical power, and the secondary reflector 102 has a hyperboloid surface with negative optical power. The first front objective lens 103 is a biconvex lens with positive optical power, and its incident surface is an aspheric surface containing even-order 8th order. The second front objective lens 104 is a biconcave lens with negative optical power, and its incident surface is an aspheric surface containing even-order 8th order. The first front objective lens 103 converges light rays, while the second front objective lens 104 diverges light rays. The use of high-order aspheric surfaces corrects aberrations, optimizes the optical path, and improves the overall imaging performance of the optical system.

[0048] The distances between the reflecting surface of the primary mirror 101 and the reflecting surface of the secondary mirror 102, the reflecting surface of the secondary mirror 102 and the incident surface of the first front objective lens 103, the incident surface of the first front objective lens 103 and the exit surface, the exit surface of the first front objective lens 103 and the incident surface of the second front objective lens 104, the incident surface of the second front objective lens 104 and the exit surface, and the exit surface of the second front objective lens 104 and the primary image plane 601 are 294.31, 405.31, 9.4, 7.48, 6.8, and 81.55 mm, respectively.

[0049] The first front objective lens 103 and the second front objective lens 104 are made of ZnSe and ZnS, respectively. The two infrared materials ZnSe and ZnS are matched to correct primary aberrations and combined with higher-order aspherical surfaces to correct higher-order aberrations, thereby improving the imaging quality. The first front objective lens 103 and the second front objective lens 104 are used to achieve image-side telecentric design.

[0050] The centerline obstruction ratio of the primary reflector 101 and the secondary reflector 102 is 0.35.

[0051] The Dyson imaging lens group 2 is used to image the infrared beam at the primary image plane 601 onto the secondary image plane 602, and to realize time-division imaging of the infrared spectrum and the infrared image using the switching device 3; the Dyson imaging lens group 2 includes a first lens 201, a second lens 202 and a third lens 203; the infrared beam at the primary image plane 601 passes through the first lens 201, the second lens 202 and the third lens 203 in sequence before entering the switching device 3.

[0052] The parameters of the first lens 201, the second lens 202, and the third lens 203 are shown in Table 2.

[0053] Table 2

[0054]

[0055] The first lens 201 is a lens with a positive optical power and a bending direction switching device 3, and the side away from the second lens 202 (the first side) is a high-order aspherical surface containing even-order 10; the second lens 202 is a lens with a positive optical power and a bending direction switching device 3, and the third lens 203 is a lens with a negative optical power and a bending direction switching device 3, containing a high-order double-sided aspherical surface containing even-order 8.

[0056] The distances between the first and second surfaces of the first lens 201, the second surface of the first lens 201 and the first surface of the second lens 202, the first and second surfaces of the second lens 202 and the first surface of the third lens 203, the first and second surfaces of the third lens 203, and the second surface of the third lens 203 and the secondary image plane 602 are 13.9, 50.24, 13.5, 1.68, 11.84, and 183.55 mm, respectively.

[0057] The first lens 201, the second lens 202, and the third lens 203 are made of Ge, Si, and Ge, respectively. The two infrared materials Ge and Si are matched to correct primary aberrations, and higher-order aspherical surfaces are added to the surface of Ge to correct higher-order aberrations, thereby achieving a dual telecentric design between the object and image sides.

[0058] The Dyson imaging lens group 2 achieves "optical path multiplexing" for incident and outgoing light, with a magnification of -1x.

[0059] The switching device 3 includes a switchable planar reflective grating and a planar reflector. The planar reflective grating is used to spectrally split the infrared beam output by the third lens 203 and reflect it back to the third lens 203. The planar reflective grating is a planar reflective blazed grating with a scribe line width of 40 μm. The planar reflector is used to reflect the infrared beam output by the third lens 203 back to the third lens 203.

[0060] The folding mirror 4 is used to fold the outgoing imaging light path in the Dyson imaging mirror group 2 and to image at the secondary image plane 602.

[0061] The relay lens group 5 is used to image the infrared beam at the secondary image plane 602 onto the image plane 603. The relay lens group 5 includes a fourth lens 501, a fifth lens 502, and a sixth lens 503 arranged sequentially along the optical path. The exit pupil (exit pupil of the system) of the relay lens group 5 is used to coincide with the cold screen of the infrared detector to meet 100% cold aperture efficiency. The image plane 603 is used to coincide with the target surface of the infrared detector.

[0062] The fourth lens 501 is a positive power lens bent towards the image plane 603; the fifth lens 502 is a negative power lens bent towards the image plane 603, containing an 8th even-order double-sided aspherical surface; and the sixth lens 503 is a positive power lens. The infrared beam output from the Dyson imaging lens group 2 passes sequentially through the fourth lens 501, the fifth lens 502, and the sixth lens 503 to be imaged at the image plane 603. The magnification of the relay lens group 5 is -0.5x.

[0063] The parameters of the fourth lens 501, the fifth lens 502, and the sixth lens 503 are shown in Table 3.

[0064] Table 3

[0065]

[0066] The distances between the incident and exit surfaces of the fourth lens 501, the distances between the exit surface of the fourth lens 501 and the incident surface of the fifth lens 502, the distances between the incident and exit surfaces of the fifth lens 502, the distances between the exit surface of the fifth lens 502 and the incident surface of the sixth lens 503, and the distances between the incident and exit surfaces of the sixth lens 503 are 12.65, 3.05, 9.08, 13.5, and 12.5 mm, respectively.

[0067] The fourth lens 501, the fifth lens 502, and the sixth lens 503 are made of Si, Ge, and Si, respectively. The two infrared materials Ge and Si are matched to correct primary aberrations, and higher-order aspherical surfaces are added to the surface of Ge to correct higher-order aberrations, thereby achieving object-side telecentric design.

[0068] The method for achieving mid-wave infrared spectral imaging and mid-wave infrared imaging based on the improved Dyson concentric structure includes the following steps:

[0069] Step 1: Construct the optical system based on the improved Dyson concentric structure to realize mid-wave infrared spectral imaging and mid-wave infrared imaging. The exit pupil of the relay lens group 5 coincides with the cold screen of the infrared detector, and the image plane 603 coincides with the target surface of the infrared detector.

[0070] Step 2: Switch the switching device 3 to a planar reflection grating;

[0071] Step 3, refer to Figure 2The infrared beam radiated by the target passes sequentially through the primary reflector 101, secondary reflector 102, first front objective lens 103, and second front objective lens 104, and is focused onto the primary image plane 601. The infrared beam at the primary image plane 601 then passes sequentially through the first lens 201, second lens 202, and third lens 203 before being projected onto a planar reflection grating. The planar reflection grating performs spectral dispersion and reflection, and the beam is then focused again through the third lens 203, second lens 202, first lens 201, and folding reflector 4, forming an image at the secondary image plane 602. The beam then spreads along the dispersion direction, such as... Figure 3 As shown; then the image is sequentially formed at image plane 603 by the fourth lens 501, the fifth lens 502, and the sixth lens 503. In the entire spectral imaging process, the limited slit field of view of the traditional spectral imaging system is broken, and mid-wave infrared spectral imaging of the target under a wide field of view is realized.

[0072] Step 4: Switch the switching device 3 to a plane mirror, and move the folding mirror 4, the relay mirror group 5, and the infrared detector as a whole, away from the image plane 603 along the optical axis of the relay mirror group 5, in order to adjust the front-to-back distance of the folding mirror 4 and the propagation path of the imaging beam, so as to ensure that the infrared beam is accurately focused on the image plane 603; the front-to-back distance of the folding mirror 4 is the distance between the folding mirror 4 and the first lens 201, and the distance between the folding mirror 4 and the fourth lens 501;

[0073] Step 5, refer to Figure 4 The infrared beam radiated by the target passes sequentially through the primary reflector 101, secondary reflector 102, first front objective lens 103, and second front objective lens 104 to be focused onto the primary image plane 601. The infrared beam at the primary image plane 601 passes sequentially through the first lens 201, second lens 202, and third lens 203 before being projected onto the plane reflector. It is reflected by the plane reflector and then passes again through the third lens 203, second lens 202, first lens 201, and folding reflector 4 to be focused onto the secondary image plane 602. Then, it passes sequentially through the fourth lens 501, fifth lens 502, and sixth lens 503 to be imaged onto the image plane 603, thus achieving mid-wave infrared imaging of the target.

[0074] The order of achieving mid-wave infrared spectral imaging of the target in a wide field of view (steps 2-3) and achieving mid-wave infrared imaging of the target (steps 4-5) can be reversed.

Claims

1. An optical system for realizing mid-wave infrared spectral imaging and mid-wave infrared imaging based on a Dyson improved concentric structure, characterized in that: It includes a front objective lens group (1), a Dyson imaging lens group (2), a switching device (3), a folding mirror (4), and a relay lens group (5); The front objective lens group (1) is used to focus the infrared beam radiated by the target onto the primary image plane (601). The front objective lens group (1) has a telecentric pupil feature and includes a primary reflector (101), a secondary reflector (102), a first front objective lens (103), and a second front objective lens (104) arranged sequentially along the optical path. The reflecting surface of the primary reflector (101) is a parabolic surface with negative optical power, the reflecting surface of the secondary reflector (102) is a hyperboloid with negative optical power, the first front objective lens (103) is a biconvex lens with positive optical power, and the second front objective lens (104) is a biconcave lens with negative optical power. The infrared beam radiated by the target passes sequentially through the primary reflector (101), the secondary reflector (102), the central through hole on the primary reflector (101), the first front objective lens (103), and the second front objective lens (104) before being focused onto the primary image plane (601). The Dyson imaging lens group (2) is used to image the infrared beam at the primary image plane (601) onto the secondary image plane (602), and to realize time-division imaging of the infrared spectrum and infrared image using the switching device (3); the Dyson imaging lens group (2) has the characteristic of object-side and image-side telecentric pupils, including a first lens (201), a second lens (202) and a third lens (203); the first lens (201) is a lens with positive optical power that is oriented towards the switching device (3), the second lens (202) is a lens with positive optical power that is oriented towards the switching device (3), and the third lens (203) is a lens with negative optical power that is oriented towards the switching device (3); the infrared beam at the primary image plane (601) passes through the first lens (201), the second lens (202) and the third lens (203) in sequence before entering the switching device (3); The switching device (3) includes a switchable planar reflective grating and a planar reflector. The planar reflective grating is used to perform spectral splitting on the infrared beam output by the third lens (203) and reflect it back to the third lens (203). The planar reflector is used to reflect the infrared beam output by the third lens (203) back to the third lens (203). The folding mirror (4) is used to fold the outgoing imaging light path in the Dyson imaging mirror group (2) and image it at the secondary image plane (602); The relay lens group (5) is used to image the infrared beam at the secondary image plane (602) onto the image plane (603); the relay lens group (5) has the characteristic of object-side telecentric pupil, including a fourth lens (501), a fifth lens (502), and a sixth lens (503) arranged sequentially along the optical path; the fourth lens (501) is a lens with positive optical power that bends toward the image plane (603), the fifth lens (502) is a lens with negative optical power that bends toward the image plane (603), and the sixth lens (503) is a lens with positive optical power; the exit pupil of the relay lens group (5) is used to coincide with the cold screen of the infrared detector, and the image plane (603) is used to coincide with the target surface of the infrared detector.

2. The optical system for realizing mid-wave infrared spectral imaging and mid-wave infrared imaging based on the improved Dyson concentric structure according to claim 1, characterized in that: The side of the first lens (201) away from the second lens (202) is a high-order aspherical surface containing even-order 10; the third lens (203) is a lens containing a high-order double-sided aspherical surface containing even-order 8.

3. The optical system for realizing mid-wave infrared spectral imaging and mid-wave infrared imaging based on the improved Dyson concentric structure according to claim 2, characterized in that: The materials of the first lens (201), the second lens (202), and the third lens (203) are Ge, Si, and Ge, respectively.

4. The optical system for realizing mid-wave infrared spectral imaging and mid-wave infrared imaging based on the improved Dyson concentric structure according to any one of claims 1 to 3, characterized in that: The incident surface of the first front objective lens (103) is an aspherical surface containing even-order 8; the incident surface of the second front objective lens (104) is an aspherical surface containing even-order 8.

5. The optical system for realizing mid-wave infrared spectral imaging and mid-wave infrared imaging based on the improved Dyson concentric structure according to claim 4, characterized in that: The materials of the first front objective lens (103) and the second front objective lens (104) are ZnSe and ZnS, respectively.

6. The optical system for realizing mid-wave infrared spectral imaging and mid-wave infrared imaging based on the improved Dyson concentric structure according to claim 5, characterized in that: The centerline obstruction ratio of the primary reflector (101) and the secondary reflector (102) is 0.

35.

7. The optical system for realizing mid-wave infrared spectral imaging and mid-wave infrared imaging based on the improved Dyson concentric structure according to claim 4, characterized in that: The fifth lens (502) is a lens containing an 8th even-order double-sided high-order aspherical surface.

8. The optical system for realizing mid-wave infrared spectral imaging and mid-wave infrared imaging based on the improved Dyson concentric structure according to claim 7, characterized in that: The fourth lens (501), the fifth lens (502), and the sixth lens (503) are made of Si, Ge, and Si, respectively.

9. A method for achieving mid-wave infrared spectral imaging and mid-wave infrared imaging based on a Dyson improved concentric structure, characterized in that, Includes the following steps: Step 1: Construct the optical system for realizing mid-wave infrared spectral imaging and mid-wave infrared imaging based on the Dyson improved concentric structure as described in claim 1. The exit pupil of the relay lens group (5) coincides with the cold screen of the infrared detector, and the image plane (603) coincides with the target surface of the infrared detector. Step 2: Switch the switching device (3) to a planar reflective grating; Step 3: The infrared beam radiated by the target is focused onto the primary image plane (601) by passing through the primary reflector (101), secondary reflector (102), first front objective lens (103), and second front objective lens (104) in sequence. The infrared beam at the primary image plane (601) passes through the first lens (201), second lens (202), and third lens (203) in sequence and is then projected onto the planar reflection grating. The planar reflection grating performs spectral dispersion and reflection, and then passes through the third lens (203), second lens (202), first lens (201), and folding reflector (4) again to focus and image onto the secondary image plane (602), and expands along the wavelength of the dispersion direction. Then, it passes through the fourth lens (501), fifth lens (502), and sixth lens (503) in sequence to image onto the image plane (603), thus realizing mid-wave infrared spectral imaging of the target in a wide field of view. Step 4: Switch the switching device (3) to a plane mirror, and move the folding mirror (4), the relay mirror group (5) and the infrared detector as a whole, away from the image plane (603) along the optical axis of the relay mirror group (5) to adjust the front and rear distance of the folding mirror (4) and the propagation path of the imaging beam, so as to ensure that the infrared beam is accurately focused on the image plane (603). Step 5: The infrared beam radiated by the target is focused onto the primary image plane (601) by the primary reflector (101), secondary reflector (102), first front objective lens (103), and second front objective lens (104) in sequence. The infrared beam at the primary image plane (601) is then projected onto the plane reflector by the first lens (201), second lens (202), and third lens (203) in sequence. After being reflected by the plane reflector, the beam is focused onto the secondary image plane (602) by the third lens (203), second lens (202), first lens (201), and folding reflector (4) in sequence. Then, it is imaged onto the image plane (603) by the fourth lens (501), fifth lens (502), and sixth lens (503) in sequence, thus achieving mid-wave infrared imaging of the target. The primary reflector (101) has a parabolic reflector with negative optical power, the secondary reflector (102) has a hyperboloid reflector with negative optical power, the first front objective (103) is a biconvex lens with positive optical power, and the second front objective (104) is a biconcave lens with negative optical power; the first lens (201) is a lens with positive optical power and a bending-direction switching device (3), the second lens (202) is a lens with positive optical power and a bending-direction switching device (3), the third lens (203) is a lens with negative optical power and a bending-direction switching device (3); the fourth lens (501) is a lens with positive optical power that bends toward the image plane (603), the fifth lens (502) is a lens with negative optical power that bends toward the image plane (603), and the sixth lens (503) is a lens with positive optical power.

Images