Long-wave refrigeration infrared optical system capable of quickly zooming

Abstract

The invention relates to the technical field of optics, in particular to a long-wave refrigeration infrared optical system capable of quickly zooming, which comprises a box body; the main lens cone is arranged in the box body; the telephoto lens group comprises a first lens, a fourth lens and an optical filter; the turnover device is configured to rotate between a first preset position and a second preset position; the zoom lens group comprises a second lens and a third lens; when the zoom lens group is cut into a light path between the first lens and the fourth lens, the optical system is in a short focal length state; when the zoom lens group cuts out of an optical path between the first lens and the fourth lens, the optical system is in a long-focal-length state; incident light enters the long-wave infrared refrigeration detector through the optical filter, and the long-wave infrared refrigeration detector receives the light and forms an image. The zoom lens group has the advantages that the zoom lens group cuts in or cuts out the light path between the first lens and the fourth lens, so that the problem that the transmittance is reduced due to the fact that a refrigeration type infrared optical system is too long and the number of lenses is too large is effectively solved.

Description

Technical Field

[0001] This invention relates to the field of optical technology, and in particular to a long-wavelength cooled infrared optical system with rapid zoom capability. Background Technology

[0002] In the design of cooled infrared optical systems, secondary imaging techniques are often used to reduce the system aperture. Although this method can effectively compress the aperture, it results in a system length that is significantly greater than the focal length. In addition, to achieve secondary imaging, the number of lenses needs to be increased, and in the optomechanical design, to reduce the axial dimension, the optical path usually needs to be folded and two or more mirrors need to be introduced, which inevitably and significantly reduces the system transmittance. Summary of the Invention

[0003] Based on this, the long-wavelength cooled infrared optical system with rapid zoom proposed in this invention effectively solves the problem of excessive length and reduced transmittance caused by too many lenses in the cooled infrared optical system by cutting into or out of the optical path between the first lens and the fourth lens.

[0004] To achieve the above objectives, the technical solution of this invention is implemented as follows: A long-wavelength cooled infrared optical system with rapid zoom capability, comprising: a housing having a light-transmitting opening for transmitting infrared light; a main lens barrel disposed within the housing; a telephoto lens group disposed within the main lens barrel, comprising a first lens, a fourth lens, and a filter arranged sequentially along the light incident direction; a flipping device disposed within the housing; the flipping device being configured to rotate between a first preset position and a second preset position; and a zoom lens group disposed on the flipping device. The system includes a second lens and a third lens arranged sequentially along the incident direction of light. When the flipping device moves the zoom lens group to a first preset position, the zoom lens group cuts into the optical path between the first lens and the fourth lens, putting the optical system in a short focal length state. When the flipping device moves the zoom lens group to a second preset position, the zoom lens group cuts out the optical path between the first lens and the fourth lens, putting the optical system in a long focal length state. A long-wave infrared cooled detector receives incident light through a filter and forms an image.

[0005] Furthermore, the flipping device includes a drive mechanism, a mounting base, a rotating shaft, and a flipping lens barrel; both the drive mechanism and the mounting base are connected to the housing; the rotating shaft is rotatably connected to the mounting base; the input end of the rotating shaft is connected to the output end of the drive mechanism; the flipping lens barrel is sleeved outside the rotating shaft; the zoom lens assembly is disposed inside the flipping lens barrel; the drive mechanism drives the flipping lens barrel through the rotating shaft, causing the zoom lens assembly to rotate between a first preset position and a second preset position.

[0006] Furthermore, the drive mechanism includes a power source, a bracket, a rack, a gear, and a slide rail; the power source is connected to the housing via the bracket; the slide rail is connected to the mounting base; the rack is movably embedded in the guide groove of the slide rail; one end of the rack is connected to the output end of the power source; the gear is sleeved on the input end of the rotating shaft and meshes with the rack; when the power source drives the rack to move along the length direction of the slide rail, the gear drives the rotating shaft and the flipping mirror tube to rotate.

[0007] Furthermore, the mounting base includes a base and two spaced-apart support frames; each support frame is provided with a mounting hole; the two ends of the rotating shaft pass through the corresponding mounting holes and are rotatably supported on the two support frames.

[0008] Furthermore, the flipping device also includes a locking bracket and a support; the locking bracket is mounted on the mounting base and is located on one side of the drive mechanism; the support is connected to the housing and is located on the side opposite to the locking bracket; when the zoom lens group enters the optical path, the flipping lens barrel is locked to the locking bracket; when the zoom lens group exits the optical path, the flipping lens barrel abuts against the support.

[0009] Furthermore, the flip lens barrel includes a lens barrel and an adapter; the first end of the adapter is connected to the lens barrel, and the second end of the adapter is sleeved on the outside of the rotating shaft; the second lens and the third lens are arranged alternately inside the lens barrel along the incident direction of light; a locking part extends radially outward from the outer periphery of the adapter; when the zoom lens group enters the optical path, the locking part locks with the locking bracket.

[0010] Furthermore, the main lens barrel includes a lens barrel body and two spaced-apart legs; the two legs are connected to the housing; the lens barrel body is mounted on the two legs; the outer circumference of the lens barrel body is provided with a clearance opening to provide clearance space for the rotation of the flipping device between a first preset position and a second preset position.

[0011] Furthermore, the first, third, and fourth lenses all have positive optical power; the second lens has negative optical power. The ratio of the long focal length to the short focal length of an optical system is: ; The ratio of the focal length of the zoom lens group to the telephoto length of the optical system is: ; The ratio of the focal length of the first lens to the focal length of the optical system is: ; The ratio of the focal length of the fourth lens to the focal length of the optical system is: ; The ratio of the focal length of the second lens to the short focal length of the optical system is: ; The ratio of the focal length of the third lens to the short focal length of the optical system is: ; The ratio of the focal length to the total length of the optical system is: ; The ratio of the short focal length to the total length of the optical system is: ; in, Indicates the focal length of the optical system; Indicates a short focal length in the optical system; Indicates the focal length of the zoom lens group; , , , These are the focal lengths of the first, second, third, and fourth lenses, respectively; T is the total length of the optical system.

[0012] Furthermore, the first lens is made of germanium single crystal with a thickness of 20mm to 30mm; the front surface of the first lens is spherical with a radius of curvature of 122mm to 168mm; and the rear surface of the first lens is aspherical. The second lens is made of germanium single crystal or zinc selenide, with a thickness of 9mm to 28mm; the front surface of the second lens is aspherical; the rear surface of the second lens is spherical, with a radius of curvature of -480mm to -∞mm. The third lens is made of zinc selenide or germanium single crystal, with a thickness of 7mm to 22mm; the front surface of the third lens is spherical with a radius of curvature of 300mm to 900mm; the rear surface of the third lens is spherical with a radius of curvature of -239mm to -450mm. The fourth lens is made of germanium single crystal with a thickness of 12mm to 28mm; the front surface of the fourth lens is spherical with a radius of curvature of 60mm to 180mm; the rear surface of the fourth lens is aspherical.

[0013] Furthermore, the maximum length of the primary lens barrel along the Y-axis direction The maximum length of the flipping device along the X-axis The ratio is: ; The maximum outer diameter R of the lens barrel and the rotation radius of the flipping device The ratio is: ; Length of telephoto lens group along the direction of light incidence Rotation radius of the flipping device The ratio is: ; Rotation radius of the flipping device Distance between the center of mass of the zoom lens assembly and the axis of rotation The ratio is: ; The X-axis and Y-axis are perpendicular to each other, and both the X-axis and Y-axis are perpendicular to the direction of light incidence.

[0014] The present invention can achieve the following beneficial effects: 1) The zoom lens group effectively solves the problem of excessive length and reduced transmittance caused by too many lenses in the cooled infrared optical system by cutting into or out the optical path between the first lens and the fourth lens.

[0015] 2) Only 4 lenses and 2 types of optical materials are used to achieve image quality correction and focal length switching for the entire optical system.

[0016] 3) The outer circumference of the lens barrel body is provided with a clearance opening, which allows the flipping device to rotate between the first preset position and the second preset position, while keeping the overall structure of the main lens barrel simple, reducing the number of assembly parts, and ensuring that the zoom lens group does not interfere when cutting into or out of the optical path.

[0017] 4) The use of a flip device to cut in or out of the optical path of the zoom lens group can save the axial length of the system compared with the traditional sliding rail switching mechanism, making the overall structure of the optical system more compact. Attached Figure Description

[0018] The accompanying drawings, which form part of this invention, are used to provide a further understanding of the invention. The illustrative embodiments and descriptions of the invention are used to explain the invention and do not constitute an undue limitation of the invention. In the drawings: Figure 1 This is a schematic diagram of the structure of a long-wavelength cooled infrared optical system with rapid zoom capability according to an embodiment of the present invention. Figure 2 This is a schematic diagram of the structure of a long-wavelength cooled infrared optical system with rapid zoom capability provided according to an embodiment of the present invention, from another perspective. Figure 3 This is a schematic diagram of the main lens barrel provided according to an embodiment of the present invention; Figure 4 This is a schematic diagram of the optical path of the zoom lens assembly according to an embodiment of the present invention; Figure 5 This is a schematic diagram of the structure of the flipping device provided in an embodiment of the present invention; Figure 6This is a schematic diagram of the structure of the flipping device provided in the embodiment of the present invention, which positions the zoom lens assembly in a first preset position and a second preset position; Figure 7 This is a schematic diagram of the drive mechanism provided according to an embodiment of the present invention; Figure 8 This is a schematic diagram of the structure of the flip lens barrel provided according to an embodiment of the present invention; Figure 9 This is a schematic diagram of the structure of the locking bracket provided according to an embodiment of the present invention; Figure 10 This is an MTF curve of the optical system provided according to an embodiment of the present invention at a short focal length of 100mm; Figure 11 This is an MTF curve of the optical system provided according to an embodiment of the present invention at a focal length of 200mm; Figure 12 This is a distortion curve diagram of the optical system provided according to an embodiment of the present invention when it is at a short focal length of 100mm; Figure 13 This is a distortion curve diagram of the optical system provided according to an embodiment of the present invention at a focal length of 200mm; Figure 14 This is an energy concentration curve of the optical system provided according to an embodiment of the present invention at a short focal length of 100mm; Figure 15 This is an energy concentration curve of the optical system provided according to an embodiment of the present invention at a focal length of 200mm.

[0019] The reference numerals in the attached drawings include: 1. Housing; 2. Main lens barrel; 21. Lens barrel body; 22. Support leg; 23. Clearance opening; 3. Telephoto lens group; 31. First lens; 32. Fourth lens; 33. Filter; 4. Tilting device; 41. Drive mechanism; 411. Power source; 412. Bracket; 413. Rack; 414. Gear; 415. Slide rail; 42. Mounting base; 43. Rotating shaft; 44. Tilting lens barrel; 441. Lens barrel; 442. Adapter; 443. Locking part; 444. Locking cavity; 45. Locking bracket; 451. Fixing block; 452. Locking block; 46. Support; 5. Zoom lens group; 51. Second lens; 52. Third lens; 6. Long-wave infrared cooled detector. Detailed Implementation

[0020] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and specific embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and do not constitute a limitation thereof.

[0021] It should be noted that, unless otherwise specified, the embodiments and features described in the present invention can be combined with each other.

[0022] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," and "outer," etc., indicating orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation on this invention. Furthermore, the terms "first," "second," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, features defined with "first," "second," etc., may explicitly or implicitly include one or more of that feature. In the description of this invention, unless otherwise stated, "a plurality of" means two or more.

[0023] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art will understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0024] The invention will now be described in detail with reference to specific embodiments.

[0025] like Figures 1 to 15 As shown in the figure, an embodiment of the present invention provides a long-wavelength cooled infrared optical system with fast zoom capability, comprising: a housing 1, a main lens barrel 2, a telephoto lens group 3, a flip device 4, a zoom lens group 5, and a long-wavelength infrared cooled detector 6.

[0026] The housing 1 has a light-transmitting opening for transmitting infrared light. The main lens barrel 2, the telephoto lens group 3, the zoom lens group 5, the flip device 4, and the long-wave infrared cooled detector 6 are all located inside the housing 1.

[0027] The main lens barrel 2 is connected to the base plate of the housing 1. The main lens barrel 2 includes a lens barrel body 21 and two spaced-apart support legs 22. The two support legs 22 are connected to the base plate of the housing 1, and the lens barrel body 21 is mounted on the two support legs 22. A clearance opening 23 is provided on the outer circumference of the lens barrel body 21. The clearance opening 23 provides clearance space for the rotation of the flipping device 4 between a first preset position and a second preset position.

[0028] In this embodiment, the first preset position is the position of the zoom lens group 5 when it enters the optical path between the first lens 31 and the fourth lens 32. The second preset position is the position of the zoom lens group 5 when it exits the optical path between the first lens 31 and the fourth lens 32.

[0029] The telephoto lens group 3 is housed within the main lens barrel 2. Along the direction of light incidence, the telephoto lens group 3 comprises a first lens 31, a fourth lens 32, and a switchable filter 33 arranged sequentially. Incident light passes through the filter 33 and enters the long-wave infrared cooled detector 6, which receives the light and forms an image.

[0030] Both the first lens 31 and the fourth lens 32 have positive optical power. The first lens 31 is made of germanium single crystal with a thickness of 20mm to 30mm. The front surface of the first lens 31 is spherical with a radius of curvature of 122mm to 168mm; the rear surface of the first lens 31 is aspherical.

[0031] The fourth lens 32 is made of germanium single crystal with a thickness of 12mm to 28mm. The front surface of the fourth lens 32 is spherical with a radius of curvature of 60mm to 180mm. The rear surface of the fourth lens 32 is aspherical.

[0032] The filter 33 is made of germanium single crystal. Both the front and back surfaces of the filter 33 are flat, and the thickness is 1.5mm to 3mm.

[0033] A flipping device 4 is disposed inside the housing 1, and the flipping device 4 is configured to rotate between a first preset position and a second preset position. In this embodiment, the rotation angle range of the flipping device 4 is 0° to 90°.

[0034] The flipping device 4 includes a drive mechanism 41, a mounting base 42, a rotating shaft 43, a flipping lens tube 44, a locking bracket 45, and a support 46.

[0035] like Figures 5 to 9 As shown, both the drive mechanism 41 and the mounting base 42 are connected to the bottom plate of the housing 1, and the mounting base 42 is located between the two legs 22 of the main lens barrel 2. A rotating shaft 43 is rotatably connected to the mounting base 42. The input end of the rotating shaft 43 is connected to the output end of the drive mechanism 41. The flip lens barrel 44 is fitted outside the rotating shaft 43. The zoom lens assembly 5 is disposed inside the flip lens barrel 44. Locking brackets 45 are all mounted on the mounting base 42, located on the side of the mounting base 42 closest to the drive mechanism 41. A support 46 is connected to the bottom plate of the housing 1 and is located on the side opposite to the locking brackets 45. The drive mechanism 41 drives the flip lens barrel 44 via the rotating shaft 43, causing the zoom lens assembly 5 to rotate between a first preset position and a second preset position. Figure 6 As shown.

[0036] When the zoom lens group 5 enters the optical path (i.e., the zoom lens group 5 is in the first preset position), the lens barrel 44 is flipped and locked with the locking bracket 45.

[0037] When the zoom lens group 5 cuts out of the optical path (i.e., the zoom lens group 5 is in the second preset position), the flip lens barrel 44 abuts against the support 46.

[0038] Furthermore, the mounting base 42 includes a base and two spaced-apart support frames. Each support frame has a mounting hole, and the two ends of the rotating shaft 43 pass through the corresponding mounting holes and are rotatably supported on the two support frames by bearings.

[0039] The drive mechanism 41 includes a power source 411, a bracket 412, a rack 413, a gear 414, and a slide rail 415. The bracket 412 is connected to the bottom plate of the housing 1, and the fixed end of the power source 411 is connected to the bracket 412.

[0040] The slide rail 415 is connected to the side wall of the mounting base 42. The slide rail 415 has a guide groove. The rack 413 is movably embedded in the guide groove. One end of the rack 413 is connected to the output end of the power source 411, and the gear 414 is sleeved on the input end of the rotating shaft 43 and meshes with the rack 413. When the power source 411 drives the rack 413 to move along the slide rail 415, the gear 414 drives the rotating shaft 43 and the flip mirror barrel 44 to rotate.

[0041] In this embodiment, the power source 411 is a DC motor.

[0042] The flip lens barrel 44 includes a lens barrel 441 and an adapter 442. The first end of the adapter 442 is connected to the lens barrel 441, and the second end of the adapter 442 is sleeved on the outside of the rotating shaft 43. A locking portion 443 extends radially outward from the outer periphery of the adapter 442. When the zoom lens assembly 5 enters the optical path, the locking portion 443 locks with the locking bracket 45.

[0043] Furthermore, the adapter 442 includes a connecting body and an arc-shaped connector. The arc-shaped connector is connected to one end of the connecting body, and the arc surface of the arc-shaped connector is adapted to the outer contour of the lens barrel 441. The other end of the connecting body is provided with a connecting hole, through which the flip lens barrel 44 is fitted onto the outside of the rotating shaft 43.

[0044] The locking part 443 has a locking cavity 444, the inner wall of which has a first inclined surface. The locking bracket 45 is connected to the base of the mounting base 42, located between the two support frames of the mounting base 42, and close to the drive mechanism 41. The locking bracket 45 includes a fixing block 451 and a locking block 452 that are perpendicular to each other. The top of the locking block 452 has a second inclined surface that matches the first inclined surface. When the locking part 443 is locked with the locking bracket 45, the top of the locking block 452 extends into the locking cavity 444, and the first inclined surface and the second inclined surface form a wedge fit. The locking fit between the locking part 443 and the locking bracket 45 is used to ensure the positional accuracy of the zoom lens assembly 5 after it enters the optical path and to prevent displacement during operation.

[0045] The support 46 is provided with an arc-shaped surface that matches the outer contour of the lens barrel 441. When the zoom lens group 5 cuts out the optical path, the flip lens barrel 44 is located on the arc-shaped surface of the support 46.

[0046] The zoom lens assembly 5 includes, along the direction of light incidence, a second lens 51 and a third lens 52 spaced apart. The second lens 51 has negative optical power. All fourth lenses 32 have positive optical power.

[0047] The second lens 51 is made of germanium single crystal or zinc selenide, and its thickness is 9mm to 28mm. The front surface of the second lens 51 is aspherical, and the rear surface of the second lens 51 is spherical, with a radius of curvature of -480mm to -∞mm.

[0048] The third lens 52 is made of zinc selenide or germanium single crystal, with a thickness of 7mm to 22mm. The front surface of the third lens 52 is spherical, with a radius of curvature of 300mm to 900mm. The rear surface of the third lens 52 is spherical, with a radius of curvature of -239mm to -450mm.

[0049] Furthermore, the ratio of the long focal length to the short focal length of the optical system is: ; The ratio of the focal length of zoom lens group 5 to the telephoto length of the optical system is: ; The ratio of the focal length of the first lens 31 to the focal length of the optical system is: ; The ratio of the focal length of the fourth lens 32 to the focal length of the optical system is: ; The ratio of the focal length of the second lens 51 to the short focal length of the optical system is: ; The ratio of the focal length of the third lens 52 to the short focal length of the optical system is: ; The ratio of the focal length to the total length of the optical system is: ; The ratio of the short focal length to the total length of the optical system is: ; in, Indicates the focal length of the optical system; Indicates a short focal length in the optical system; This indicates the focal length of zoom lens group 5; , , , These are the focal lengths of the first lens 31, the second lens 51, the third lens 52, and the fourth lens 32, respectively; T is the total length of the optical system.

[0050] like Figures 10 to 15 The figures show the MTF curve, distortion curve, and energy concentration curve of the optical system when the short focal length is 100mm and the long focal length is 200mm, respectively. It can be seen from the figures that the optical system meets the usage requirements.

[0051] Figure 10 This is the MTF curve of the optical system at a short focal length of 100mm.

[0052] Figure 11 This is the MTF curve of the optical system at a focal length of 200mm.

[0053] Figure 12 This is a distortion curve of the optical system at a short focal length of 100mm.

[0054] Figure 13 This is a distortion curve of the optical system at a focal length of 200mm.

[0055] Figure 14 This is a graph showing the energy concentration of the optical system at a short focal length of 100mm.

[0056] Figure 15 This is a graph showing the energy concentration of the optical system at a focal length of 200mm.

[0057] Furthermore, such as Figure 2 and Figure 6 As shown, the maximum length of the main lens barrel 2 along the Y-axis is... The maximum length of the flipping device 4 along the X-axis direction (That is, when the flip lens tube 44 is in the second preset position, the ratio of the length of the flipping device 4 along the X-axis is:) ; The maximum outer diameter R of the lens barrel 441 and the rotation radius of the flipping device 4 The ratio is: ; The length of the telephoto lens group 3 along the direction of light incidence Rotation radius of the flipping device 4 The ratio is: ; Rotation radius of flipping device 4 The distance between the center of mass of zoom lens group 5 and the axis of rotation 43 The ratio is: ; The X-axis and Y-axis are perpendicular to each other, and both the X-axis and Y-axis are perpendicular to the direction of light incidence.

[0058] In this embodiment, the relative aperture of the fast-zooming long-wave cooled infrared optical system is F / 2, the matching image plane resolution is 640×512, the matching pixel size is 25um, and the operating wavelength is 7.7um~9.4um.

[0059] In summary, by cutting into or out the optical path between the first and fourth lenses, the magnifying lens group effectively solves the problem of excessive length and reduced transmittance caused by too many lenses in the cooled infrared optical system.

[0060] The entire optical system achieves image quality correction and focal length switching using only 4 lenses and 2 optical materials.

[0061] The outer circumference of the lens barrel body is provided with a clearance opening, which allows the flipping device to rotate between the first preset position and the second preset position, while maintaining the overall structure of the main lens barrel is simple, reducing the number of assembly parts, and ensuring that the zoom lens group does not interfere when cutting into or out of the optical path.

[0062] The use of a flipping device to cut in or out of the optical path of the zoom lens group can save the axial length of the system compared with the traditional sliding rail switching mechanism, making the overall structure of the optical system more compact.

[0063] The specific embodiments described above do not constitute a limitation on the scope of protection of this invention. Those skilled in the art should understand that various modifications, combinations, sub-combinations, and substitutions can be made according to design requirements and other factors. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of this invention should be included within the scope of protection of this invention.

Claims

1. A long-wavelength cooled infrared optical system with rapid zoom capability, characterized in that, include: The enclosure has a light-transmitting opening for infrared light to pass through; The main lens barrel is disposed inside the housing; A telephoto lens assembly, wherein the telephoto lens assembly is disposed within the main lens barrel, and includes a first lens, a fourth lens, and a filter arranged sequentially along the light incident direction; A flipping device is disposed inside the box; the flipping device is configured to rotate between a first preset position and a second preset position. A zoom lens assembly, which is mounted on the flipping device, includes a second lens and a third lens arranged sequentially along the light incident direction; When the flipping device positions the zoom lens group in the first preset position, the zoom lens group cuts into the optical path between the first lens and the fourth lens, so that the optical system is in a short focal length state. When the flipping device moves the zoom lens group to the second preset position, the zoom lens group cuts out the optical path between the first lens and the fourth lens, so that the optical system is in a long focal length state. The long-wave infrared cooled detector receives incident light through the filter and forms an image.

2. The long-wavelength cooled infrared optical system with rapid zoom capability according to claim 1, characterized in that, The flipping device includes a drive mechanism, a mounting base, a rotating shaft, and a flipping mirror tube; The drive mechanism and the mounting base are both connected to the housing; the rotating shaft is rotatably connected to the mounting base; the input end of the rotating shaft is connected to the output end of the drive mechanism; the flip lens barrel is sleeved outside the rotating shaft; the zoom lens group is disposed inside the flip lens barrel; The drive mechanism drives the flip lens barrel through the rotating shaft, causing the zoom lens assembly to rotate between the first preset position and the second preset position.

3. The long-wavelength cooled infrared optical system with rapid zoom capability according to claim 2, characterized in that, The drive mechanism includes a power source, a bracket, a rack, a gear, and a slide rail; The power source is connected to the housing via a bracket; the slide rail is connected to the mounting base; the rack is movably embedded in the guide groove of the slide rail; one end of the rack is connected to the output end of the power source; the gear is sleeved on the input end of the rotating shaft and meshes with the rack. When the power source drives the rack to move along the length of the slide rail, the gear drives the rotating shaft and the flipping mirror barrel to rotate.

4. The long-wavelength cooled infrared optical system with rapid zoom capability according to claim 2, characterized in that, The mounting base includes a base and two spaced-apart support frames; each support frame is provided with a mounting hole; the two ends of the rotating shaft pass through the corresponding mounting holes and are rotatably supported on the two support frames.

5. The long-wavelength cooled infrared optical system with rapid zoom capability according to claim 2, characterized in that, The flipping device further includes a locking bracket and a support; the locking bracket is mounted on the mounting base and is located on one side of the drive mechanism; the support is connected to the housing and is located on the side opposite to the locking bracket. When the zoom lens group enters the optical path, the flip lens barrel locks with the locking bracket; When the zoom lens group cuts out of the optical path, the flip lens barrel abuts against the support.

6. The long-wavelength cooled infrared optical system with rapid zoom capability according to claim 5, characterized in that, The flip lens barrel includes a lens barrel and an adapter; the first end of the adapter is connected to the lens barrel, and the second end of the adapter is sleeved on the outside of the rotating shaft; the second lens and the third lens are arranged sequentially and spaced apart inside the lens barrel along the incident direction of light; a locking part extends radially outward from the outer periphery of the adapter; when the zoom lens group enters the optical path, the locking part locks with the locking bracket.

7. The long-wavelength cooled infrared optical system with rapid zoom capability according to claim 1, characterized in that, The main lens barrel includes a lens barrel body and two spaced-apart legs; the two legs are connected to the housing; the lens barrel body is mounted on the two legs; The outer circumference of the lens barrel body is provided with a clearance opening to provide clearance space for the rotation of the flipping device between the first preset position and the second preset position.

8. The long-wavelength cooled infrared optical system with rapid zoom capability according to claim 1, characterized in that, The first lens, the third lens, and the fourth lens all have positive optical power; the second lens has negative optical power. The ratio of the long focal length to the short focal length of the optical system is: ； The ratio of the focal length of the zoom lens group to the telephoto length of the optical system is: ； The ratio of the focal length of the first lens to the focal length of the optical system is: ； The ratio of the focal length of the fourth lens to the focal length of the optical system is: ； The ratio of the focal length of the second lens to the short focal length of the optical system is: ； The ratio of the focal length of the third lens to the short focal length of the optical system is: ； The ratio of the focal length of the optical system to the total length of the optical system is: ； The ratio of the short focal length to the total length of the optical system is: ； in, Indicates the focal length of the optical system; Indicates a short focal length in the optical system; This indicates the focal length of the zoom lens group; , , , These are the focal lengths of the first lens, the second lens, the third lens, and the fourth lens, respectively; T is the total length of the optical system.

9. The long-wavelength cooled infrared optical system with rapid zoom capability according to claim 8, characterized in that, The first lens is made of germanium single crystal with a thickness of 20mm to 30mm; the front surface of the first lens is spherical with a radius of curvature of 122mm to 168mm; the rear surface of the first lens is aspherical. The second lens is made of germanium single crystal or zinc selenide, with a thickness of 9mm to 28mm; the front surface of the second lens is aspherical; the rear surface of the second lens is spherical, with a radius of curvature of -480mm to -∞mm. The third lens is made of zinc selenide or germanium single crystal, with a thickness of 7mm to 22mm; the front surface of the third lens is spherical with a radius of curvature of 300mm to 900mm; the rear surface of the third lens is spherical with a radius of curvature of -239mm to -450mm. The fourth lens is made of germanium single crystal with a thickness of 12mm to 28mm; the front surface of the fourth lens is spherical with a radius of curvature of 60mm to 180mm; the rear surface of the fourth lens is aspherical. The filter is made of germanium single crystal, with both its front and back surfaces being planar and its thickness ranging from 1.5 mm to 3 mm.

10. The long-wavelength cooled infrared optical system with rapid zoom capability according to claim 6, characterized in that, The maximum length of the main lens barrel along the Y-axis direction The maximum length of the flipping device along the X-axis direction The ratio is: ； The maximum outer diameter R of the lens barrel and the rotation radius of the flipping device The ratio is: ； The length of the telephoto lens group along the direction of light incidence Rotation radius of the flipping device The ratio is: ； The rotation radius of the flipping device The distance between the center of mass of the zoom lens assembly and the axis of rotation The ratio is: ； The X-axis and Y-axis are perpendicular to each other, and both the X-axis and Y-axis are perpendicular to the direction of light incidence.

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