CN214122557U

CN214122557U - Refrigeration type wide-angle infrared dual-waveband optical system

Info

Publication number: CN214122557U
Application number: CN202022938258.XU
Authority: CN
Inventors: 栗洋洋; 刘琳; 彭晴晴
Original assignee: CETC 11 Research Institute
Current assignee: CETC 11 Research Institute
Priority date: 2020-12-10
Filing date: 2020-12-10
Publication date: 2021-09-03
Anticipated expiration: 2030-12-10

Abstract

The utility model discloses a refrigeration type wide angle infrared dual waveband optical system. The optical system includes: the lens comprises a first lens, a second lens, a third lens and a fourth lens which are coaxial and arranged at intervals in sequence; a spectroscope for reflecting the medium wave band and transmitting the long wave band, which is positioned between the second lens and the third lens; the central axis of the fifth lens and the central axis of the second lens are intersected with the spectroscope; the first lens has negative focal power, and the other lenses have positive focal power; the first lens, the second lens, the third lens, the fourth lens and the beam splitter form a long-wave light path, the first lens, the second lens, the fifth lens, the sixth lens and the beam splitter form a medium-wave light path, the F number, the focal length and the half-field angle of the medium-wave light path are F1, F1 'and w1 in sequence, the F number, the focal length and the half-field angle of the long-wave light path are F2, F2' and w2 in sequence, F1 is larger than or equal to 1.4 and smaller than or equal to F2 and smaller than or equal to 1.8, F1 'is larger than or equal to 7mm and smaller than or equal to F2' and smaller than or equal to 16mm, and 2w1 is larger than or equal to 92 degrees and smaller than or equal to 2w2 and smaller than or equal to 120 degrees. Thus, dual-band imaging with a small F number and a wide field of view can be realized.

Description

Refrigeration type wide-angle infrared dual-waveband optical system

Technical Field

The utility model relates to the field of optical technology, especially, relate to an infrared dual waveband optical system of refrigeration type wide angle.

Background

With the development of the camouflage technology, the information quantity of a single wave band acquired by a single wave band infrared imaging system is limited, and particularly for scenes with complex target backgrounds, variable climatic environments and the like, the single wave band infrared reconnaissance alarm system cannot meet the reconnaissance and identification of targets. The medium-wave and long-wave dual-band detection can simultaneously acquire the dual-band information of the target, and the complex background can be suppressed through image fusion, so that the detection and identification capabilities of the target are improved.

In the related art, the form of the dual-band detection optical system includes a branch optical path and a common optical path. The optical design in the form of light splitting paths has the advantages of large system volume, complex structure and low reliability; the optical design of the common optical path mode has the advantages of more lenses, low transmittance and high cost, and especially, a large-area-array dual-band detector in a wide-angle system is not developed to be mature.

SUMMERY OF THE UTILITY MODEL

An embodiment of the utility model provides an infrared dual waveband optical system of refrigeration type wide angle for optical design that the branch light path exists the reliability low, the transmissivity is low, working range is little, the cost is expensive scheduling problem in the solution prior art with the common light path.

According to the utility model discloses refrigeration type wide angle infrared dual waveband optical system, include:

the lens comprises a first lens, a second lens, a third lens and a fourth lens which are coaxial and arranged at intervals in sequence;

a beam splitter located between the second lens and the third lens, the beam splitter being configured to reflect a medium-wave band and transmit a long-wave band;

the fifth lens is positioned below the spectroscope, and the central axis of the fifth lens and the central axis of the second lens are intersected with the spectroscope;

a sixth lens, which is positioned below the fifth lens and is coaxially arranged with the fifth lens;

the first lens has a negative optical power, and the second lens, the third lens, the fourth lens, the fifth lens, and the sixth lens each have a positive optical power;

the first lens, the second lens, the beam splitter, the third lens and the fourth lens are configured to form a long-wave light path, the first lens, the second lens, the beam splitter, the fifth lens and the sixth lens are configured to form a medium-wave light path, and a focal length f1 'of the medium-wave light path and a focal length f 2' of the long-wave light path satisfy: f1 'is equal to or less than 7mm, f 2' is equal to or less than 16mm, and the half field angle w1 of the medium wave optical path and the half field angle w2 of the long wave optical path meet the following conditions: 2w1 is more than or equal to 92 degrees and less than or equal to 120 degrees, 2w 2.

According to some embodiments of the invention, the F-number F1 of the medium wave optical path and the F-number F2 of the long wave optical path satisfy: f2 is not less than 1.8 and is not less than 1.4 and not more than F1.

According to some embodiments of the present invention, the first lens, the second lens, the third lens, and the fifth lens are all meniscus-shaped, and the first lens is convex toward a direction away from the second lens, the second lens is convex toward the third lens, the third lens is convex toward the second lens, and the fifth lens is convex toward the beam splitter;

the fourth lens and the sixth lens are both of a double-sided convex type, the thickness of the fourth lens is gradually reduced from the center of the fourth lens to the peripheral direction, and the thickness of the sixth lens is gradually reduced from the center of the sixth lens to the peripheral direction.

According to some embodiments of the invention, the first lens, the second lens, the third lens, the fourth lens, the sixth lens are all germanium lenses;

the fifth lens is a silicon lens;

the spectroscope is a germanium spectroscope.

According to some embodiments of the invention, the beam splitter is a planar beam splitter;

the spectroscope is suitable for reflecting a wave band with a wavelength within the range of 3.5-4.8 mu m and transmitting a wave band with a wavelength within the range of 7.5-11 mu m.

According to some embodiments of the utility model, the spectroscope orientation one side of second lens is equipped with the beam split membrane, the spectroscope orientation one side of third lens is equipped with the antireflection coating.

According to some embodiments of the invention, the aperture of the first lens satisfies: 4.1 < D/f1 ═ D/f2 < 5.3.

According to the utility model discloses a some embodiments, refrigeration type wide angle infrared dual waveband optical system still includes:

the long-wave diaphragm is positioned on one side, far away from the third lens, of the fourth lens, and the long-wave diaphragm and the fourth lens are coaxial and arranged at intervals;

and the medium wave diaphragm is positioned on one side of the sixth lens, which is far away from the fifth lens, and the medium wave diaphragm and the sixth lens are coaxial and are arranged at intervals.

According to some embodiments of the invention, a front-to-back spacing of the fourth lens is adjustable;

the front-back distance of the sixth lens is adjustable.

According to some embodiments of the present invention, the phase equation of the sixth lens when the center wavelength λ 0 undergoes + m order diffraction is:

phi is the phase of each point on the diffraction surface, N is the order number of the phase equation, i is the order, + m is the diffraction order, alpha i is the order coefficient, r is the radial coordinate of the diffraction zone, lambda 0 is the central wavelength of + m diffraction, N is the refractive index of the material at the wavelength lambda 0, and C1, C2 and C3 are the diffraction surface coefficients respectively.

Adopt the embodiment of the utility model provides an, utilize the spectroscope to carry out the beam split to medium wave band and long wave band, cooperate a plurality of lens, can realize the part and visit optical system with the dual waveband of light path altogether, simple structure and low cost adopt wide angle field of view design moreover, are favorable to enlarging observation scope, and the formation of image target surface is big, the refrigeration type detector of the little target surface of downward compatible.

The above description is only an overview of the technical solutions of the present invention, and in order to make the technical means of the present invention more clearly understood, the present invention may be implemented according to the content of the description, and in order to make the above and other objects, features, and advantages of the present invention more obvious and understandable, the following detailed description of the present invention is given.

Drawings

Various other advantages and benefits will become apparent to those of ordinary skill in the art upon reading the following detailed description of the embodiments. The drawings are only for purposes of illustrating the preferred embodiments and are not to be construed as limiting the invention. In the drawings:

fig. 1 is a schematic structural view of a refrigeration type wide-angle infrared dual-band optical system in an embodiment of the present invention;

FIG. 2 is a graph of the transfer function of a 3.5-4.8 μm (medium wave) band at a characteristic frequency in an embodiment of the present invention;

FIG. 3 is a graph of the transfer function of a 7.5-11 μm (long wavelength) band at a characteristic frequency in an embodiment of the present invention;

FIG. 4 is a distorted grid diagram of 3.5-4.8 μm (medium wave) band in the embodiment of the present invention;

FIG. 5 is a distorted grid diagram of 7.5-11 μm (long wave) band in the embodiment of the present invention;

FIG. 6 is a dot-column diagram of a 3.5-4.8 μm (medium wave) band in an embodiment of the present invention;

FIG. 7 is a dot-column diagram of a 7.5-11 μm (long wave) band in an embodiment of the present invention.

Reference numerals:

a first lens G1, a second lens G2, a third lens G3, a fourth lens G4, a fifth lens G5, a sixth lens G6,

the light-splitting mirror M1 is,

a long wave diaphragm C1, and a medium wave diaphragm C2.

Detailed Description

Exemplary embodiments of the present invention will be described in more detail below with reference to the accompanying drawings. While exemplary embodiments of the invention are shown in the drawings, it should be understood that the invention can be embodied in various forms and should not be limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art.

As shown in fig. 1, according to the utility model discloses refrigeration type wide angle infrared dual waveband optical system, include:

the lens comprises a first lens G1, a second lens G2, a third lens G3 and a fourth lens G4 which are coaxially and alternately arranged in sequence;

a beam splitter M1 located between the second lens G2 and the third lens G3, the beam splitter M1 being configured to reflect the medium wave band and transmit the long wave band;

the fifth lens G5 is positioned below the beam splitter M1, and the central axis of the fifth lens G5 and the central axis of the second lens G2 intersect at the beam splitter M1;

a sixth lens G6 positioned below the fifth lens G5 and coaxially disposed with the fifth lens G5;

the first lens G1 has negative power, and the second lens G2, the third lens G3, the fourth lens G4, the fifth lens G5, and the sixth lens G6 each have positive power;

the first lens G1, the second lens G2, the beam splitter M1, the third lens G3 and the fourth lens G4 are configured to form a long-wave optical path, the first lens G1, the second lens G2, the beam splitter M1, the fifth lens G5 and the sixth lens G6 are configured to form a medium-wave optical path, and the focal length f1 'of the medium-wave optical path and the focal length f 2' of the long-wave optical path satisfy the following conditions: f1 'is not less than 7mm, f 2' is not less than 16mm, and the half field angle w1 of the medium wave optical path and the half field angle w2 of the long wave optical path meet the following requirements: 2w1 is more than or equal to 92 degrees and less than or equal to 120 degrees, 2w 2.

Adopt the embodiment of the utility model provides an utilize spectroscope M1 to carry out the beam split to medium wave band and long wave band, cooperate a plurality of lens, can realize the part and visit optical system with the dual-band of light path altogether, simple structure and low cost adopt wide angle field of view design moreover, are favorable to enlarging observation scope, and the formation of image target surface is big, can be compatible little target surface's refrigeration type detector downwards.

On the basis of the above-described embodiment, various modified embodiments are further proposed, and it is to be noted herein that, in order to make the description brief, only the differences from the above-described embodiment are described in the various modified embodiments.

According to some embodiments of the invention, the F-number F1 of the medium wave optical path and the F-number F2 of the long wave optical path satisfy: f2 is not less than 1.8 and is not less than 1.4 and not more than F1. The optical design of the small F number and wide angle field can provide higher resolution and larger target detection range, and meets the use requirements of a large-target-surface and high-resolution detector.

As shown in fig. 1, according to some embodiments of the present invention, the first lens G1, the second lens G2, the third lens G3, and the fifth lens G5 are all meniscus-shaped, and the first lens G1 is convex toward a direction away from the second lens G2, the second lens G2 is convex toward the third lens G3, the third lens G3 is convex toward the second lens G2, and the fifth lens G5 is convex toward the beam splitter M1;

the fourth lens G4 and the sixth lens G6 are both double-sided convex, and the thickness of the fourth lens G4 gradually decreases from the center of the fourth lens G4 to the periphery, and the thickness of the sixth lens G6 gradually decreases from the center of the sixth lens G6 to the periphery.

Further, the concave surface of the second lens G2 (i.e., the surface of the second lens G2 on the side facing the first lens G1) is aspheric to correct coma and astigmatism of the optical system. The rear surface of the fourth lens G4 (i.e., the surface of the fourth lens G4 on the side away from the third lens G3) is aspheric for correcting spherical aberration, astigmatism and coma on the long-wave optical path of the optical system. The rear surface of the sixth lens G6 (i.e., the surface of the sixth lens G6 on the side away from the fifth lens G5) is a diffraction surface for correcting chromatic aberration of the optical path of the wave in the optical system. Furthermore, the diffraction surface is aspheric and is used for correcting spherical aberration, astigmatism and coma aberration of the wave path in the optical system.

According to some embodiments of the present invention, the first lens G1, the second lens G2, the third lens G3, the fourth lens G4, the sixth lens G6 are all germanium lenses;

the fifth lens G5 is a silicon lens;

beam splitter M1 is a germanium beam splitter.

Thus, the processing cost of the optical system can be effectively reduced.

According to some embodiments of the present invention, beamsplitter M1 is a planar beamsplitter;

the beam splitter M1 is suitable for reflecting the wave band with the wavelength ranging from 3.5 mu M to 4.8 mu M and transmitting the wave band with the wavelength ranging from 7.5 mu M to 11 mu M.

According to some embodiments of the present invention, the spectroscope M1 is provided with a spectroscopic film on one side facing the second lens G2, and the spectroscope M1 is provided with an antireflection film on one side facing the third lens G3.

According to some embodiments of the present invention, the aperture of the first lens G1 satisfies: 4.1 < D/f1 ═ D/f2 < 5.3. Therefore, on the premise of ensuring the large visual field of the optical system, the optical system can be more compact in structure and lower in processing cost.

the long-wave diaphragm C1 is positioned on the side, far away from the third lens G3, of the fourth lens G4, and the long-wave diaphragm C1 is coaxial with and spaced from the fourth lens G4;

and the medium wave diaphragm C2 is positioned on the side, away from the fifth lens G5, of the sixth lens G6, and the medium wave diaphragm C2 is coaxial with and spaced from the sixth lens G6.

According to some embodiments of the present invention, the front-to-back spacing of the fourth lens G4 is adjustable;

the front-to-back spacing of the sixth lens G6 is adjustable.

According to some embodiments of the present invention, the distance between the fourth lens G4 and the third lens G3 is adjustable; the distance between the sixth lens G6 and the fifth lens G5 is adjustable.

Therefore, mechanical temperature compensation can be realized, and clear imaging in a temperature range of-40 ℃ to 60 ℃ can be met. Specifically, when the temperature changes to a low temperature, the fourth lens G4 and the sixth lens G6 move simultaneously along the axial object direction; when the temperature changes to a high temperature, the fourth lens G4 and the sixth lens G6 simultaneously move in the axial image direction.

According to some embodiments of the present invention, the phase equation of the sixth lens G6 when the + m order diffraction occurs at the center wavelength λ 0 is:

A refrigeration-type wide-angle infrared dual-band optical system according to an embodiment of the present invention is described in detail below in a specific embodiment with reference to fig. 1 to 7. It is to be understood that the following description is illustrative only and is not intended as a specific limitation on the invention. All adopt the utility model discloses a similar structure and similar change all should be listed in the protection scope of the utility model.

As shown in fig. 1, the utility model discloses refrigeration type wide angle infrared dual-band optical system (hereinafter referred to as optical system) of embodiment includes: a first lens G1, a second lens G2, a third lens G3, a fourth lens G4, a beam splitter M1, a fifth lens G5, a sixth lens G6, a long wave diaphragm C1, and a medium wave diaphragm C2.

Specifically, the first lens G1, the second lens G2, the third lens G3 and the fourth lens G4 are coaxially and alternately arranged in sequence. The beam splitter M1 is located between the second lens G2 and the third lens G3, and the beam splitter M1 is used for reflecting the middle wave band and transmitting the long wave band to realize wide-angle dual-band imaging. The fifth lens G5 is located below the beam splitter M1, and the central axis of the fifth lens G5 and the central axis of the second lens G2 intersect at the center of the beam splitter M1. The sixth lens G6 is located below the fifth lens G5 and is disposed coaxially with the fifth lens G5.

The first lens G1, the second lens G2, the third lens G3 and the fifth lens G5 are meniscus-shaped, the first lens G1 protrudes in a direction away from the second lens G2, the second lens G2 protrudes toward the third lens G3, the third lens G3 protrudes toward the second lens G2, and the fifth lens G5 protrudes toward the beam splitter M1. The fourth lens G4 and the sixth lens G6 are both double-sided convex, and the thickness of the fourth lens G4 gradually decreases from the center of the fourth lens G4 to the periphery, and the thickness of the sixth lens G6 gradually decreases from the center of the sixth lens G6 to the periphery.

The aperture of the first lens G1 satisfies: 4.1 < D/f1 ═ D/f2 < 5.3. The concave surface of the second lens G2 (i.e., the surface of the second lens G2 on the side facing the first lens G1) is aspheric to correct coma and astigmatism of the optical system. The rear surface of the fourth lens G4 (i.e., the surface of the fourth lens G4 on the side away from the third lens G3) is aspheric for correcting spherical aberration, astigmatism and coma on the long-wave optical path of the optical system. The rear surface of the sixth lens G6 (i.e., the surface of the sixth lens G6 on the side away from the fifth lens G5) is a diffraction surface for correcting chromatic aberration of the optical path of the wave in the optical system. Furthermore, the diffraction surface is aspheric and is used for correcting spherical aberration, astigmatism and coma aberration of the wave path in the optical system. The distance between the fourth lens G4 and the third lens G3 is adjustable. The distance between the sixth lens G6 and the fifth lens G5 is adjustable.

The phase equation of the sixth lens G6 for + m order diffraction at the center wavelength λ 0 is:

The first lens G1, the second lens G2, the third lens G3, the fourth lens G4, and the sixth lens G6 are all germanium lenses. The fifth lens G5 is a silicon lens. Beam splitter M1 is germanium beam splitter M1. Beam splitter M1 is planar beam splitter M1; a beam splitter film is arranged on one side of the beam splitter M1 facing the second lens G2, and an antireflection film is arranged on one side of the beam splitter M1 facing the third lens G3. The beam splitter M1 is suitable for reflecting the wave band with the wavelength ranging from 3.5 mu M to 4.8 mu M and transmitting the wave band with the wavelength ranging from 7.5 mu M to 11 mu M.

And the long-wave diaphragm C1 is positioned on the side, far away from the third lens G3, of the fourth lens G4, and the long-wave diaphragm C1 is coaxial with and spaced from the fourth lens G4. And the medium wave diaphragm C2 is positioned on the side, away from the fifth lens G5, of the sixth lens G6, and the medium wave diaphragm C2 is coaxial with and spaced from the sixth lens G6. The first grating and the second grating are respectively superposed with the cold light barriers of the long-wave detector and the medium-wave detector so as to realize 100% of cold light barrier efficiency. The F-number of the optical system is the same as the aperture of the applicable detector.

The first lens G1, the second lens G2, the beam splitter M1, the third lens G3, and the fourth lens G4 are configured to form a long-wave optical path. The first lens G1, the second lens G2, the beam splitter M1, the fifth lens G5, and the sixth lens G6 are configured to form a medium wave optical path. The focal length f1 'of the medium wave optical path and the focal length f 2' of the long wave optical path satisfy that: f1 'is not less than 7mm, and f 2' is not less than 16 mm. The half field angle w1 of the medium wave optical path and the half field angle w2 of the long wave optical path satisfy: 2w1 is more than or equal to 92 degrees and less than or equal to 120 degrees, 2w 2. F number F1 of the medium wave optical path and F number F2 of the long wave optical path satisfy: f2 is not less than 1.8 and is not less than 1.4 and not more than F1.

Further, the aperture of the refrigeration type wide-angle infrared dual-band optical system is the same as that of the refrigeration type detector; the diaphragm of the refrigeration wide-angle infrared dual-band optical system is superposed with the cold light diaphragm of the refrigeration detector.

The embodiment of the utility model adopts the aspheric surface and the diffraction surface technology, the system structure is simple, the transmittance is high, the cost is low, and the imaging performance is good; moreover, the design of small F number is adopted, so that the light collecting capacity and the imaging resolution of the system are improved; in addition, the wide-angle view field design is adopted, the observation range is favorably enlarged, the imaging target surface is large, and the refrigeration type detector can be downward compatible with the small target surface.

For example, each lens, spectroscope and each diaphragm are prepared according to the parameters listed in tables 1-4, the two-waveband focal length of the optical system can reach 8.5mm, the F number can reach 1.5, the field angle can reach +/-56 degrees, the total length of the medium-wave optical path is 165mm, the total length of the long-wave optical path is 170mm, and the working waveband is 3.5-4.8 μm and 7.5-11 μm.

TABLE 1 Medium wave optical system parameter table

TABLE 2 Long-wave optical system parameter table

Table 3 aspheric coefficients.

TABLE 4 diffraction surface coefficients

Surface of	Center wavelength	Diffraction order	A	B	C
						S3	4μm	1	-2.23659e-5	9.25807e-9	-1.28937e-12

In tables 1 and 2, the radius of curvature is the radius of curvature of each surface in mm. The spacing is the distance between two adjacent surfaces in mm.

Additionally, the embodiment of the utility model provides an aspheric surface and diffraction face have been designed, wherein, the aspheric surface equation of face type is:

in the above formula, Z is an aspheric rise; c is the vertex curvature radius; k is a conic coefficient; A. b, C, D are aspheric coefficients, respectively; r is the radial coordinate on the aspheric surface.

The diffraction surface satisfies the following equation:

wherein phi is the phase of each point on the diffraction surface; n is the order of the phase equation; i is the order; + m is the diffraction order; alpha i is a rank coefficient; r is the radial coordinate of the diffraction zone; λ 0 is the central wavelength of + m order diffraction; n is the refractive index of the material at wavelength λ 0; c1, C2, and C3 are diffraction surface coefficients, respectively.

Fig. 2 and fig. 3 are schematic diagrams of optical transfer functions of the optical system according to an embodiment of the present invention, and it can be seen from the diagrams that the optical transfer function of the 3.5-4.8 μm wavelength band at the pair of the medium-wave characteristic frequency 33 lines is greater than 0.5, and the optical transfer function of the 7.5-11 μm wavelength band at the pair of the long-wave characteristic frequency 20 lines is greater than 0.5, so that the optical system has good imaging quality.

Fig. 4 and 5 are distortion grid diagrams of the medium wave optical path and the long wave optical path respectively, and it can be seen from the diagrams that the distortion of the medium wave and the long wave are the same, and the distortion correction can be simultaneously performed on the medium wave and the long wave images.

Fig. 6 and 7 are the dot diagrams of the medium wave system and the long wave system, respectively, and it can be seen from the diagrams that the root mean square value of the dot diagrams is smaller than the diameter of the airy disk, and the dot diagrams have good image resolution.

The utility model discloses a part is aperture form altogether, utilizes the spectroscope to carry out the beam split to the long wave, has realized wide angle dual waveband formation of image. The optical system adopts aspheric surface and diffraction surface technology, only uses two materials of germanium single crystal and silicon single crystal, balances various aberrations of dual-waveband and wide field of view by optimizing parameters of each surface, enables the image quality of medium and long waves to reach the diffraction limit, and improves the working range and the resolution capability of the system while reducing the cost.

Finally, it should be noted that although the preferred embodiments of the present invention have been disclosed for illustrative purposes, those skilled in the art will appreciate that various modifications, additions and substitutions are possible, and that the scope of the present invention should not be limited to the embodiments disclosed. The embodiment is only for illustrating the present invention and not for limiting the technical solution of the present invention; any dual wave bands included in the medium wave band and the long wave band of the present invention are all included in the scope of the claims claimed in the present invention; any improvement that does not depart from the technical solution of the present invention is intended to be covered by the scope of the claims of the present invention.

Furthermore, in the description provided herein, numerous specific details are set forth. It is understood, however, that embodiments of the invention may be practiced without these specific details. In some instances, well-known methods, structures and techniques have not been shown in detail in order not to obscure an understanding of this description.

Claims

1. A refrigerated wide-angle infrared dual-band optical system, comprising:

2. The refrigerant-type wide-angle infrared dual-band optical system as set forth in claim 1, wherein F-number F1 of said medium-wave optical path and F-number F2 of said long-wave optical path satisfy: f2 is not less than 1.8 and is not less than 1.4 and not more than F1.

3. The refrigeration wide-angle infrared dual band optical system of claim 2 wherein the first lens, the second lens, the third lens, and the fifth lens are meniscus shaped, and the first lens is convex toward the second lens, the second lens is convex toward the third lens, the third lens is convex toward the second lens, and the fifth lens is convex toward the beam splitter;

4. The refrigeration wide-angle infrared dual band optical system of claim 2, wherein the first lens, the second lens, the third lens, the fourth lens, and the sixth lens are germanium lenses;

the fifth lens is a silicon lens;

the spectroscope is a germanium spectroscope.

5. The refrigerated wide-angle infrared dual-band optical system of claim 1 wherein the beam splitter is a planar beam splitter;

6. The cryogenic wide-angle infrared dual-band optical system of claim 1,

and a light splitting film is arranged on one side of the light splitter, which faces the second lens, and an antireflection film is arranged on one side of the light splitter, which faces the third lens.

7. The refrigerated wide-angle infrared dual-band optical system of claim 1 wherein the first lens has a caliber that satisfies: 4.1 < D/f1 ═ D/f2 < 5.3.

8. The refrigerated wide-angle infrared dual-band optical system as recited in claim 1 further comprising:

9. The refrigeration wide-angle infrared dual-band optical system of claim 1, wherein the front-to-back spacing of the fourth lens is adjustable;

the front-back distance of the sixth lens is adjustable.

10. The refrigeration type wide-angle infrared dual-band optical system of claim 1, wherein the phase equation of the sixth lens when the center wavelength λ 0 undergoes + m order diffraction is: