Low-cost large-target-surface infrared continuous zoom lens

Abstract

The utility model relates to a low-cost large-target-surface infrared continuous zoom lens, which belongs to the technical field of optical lenses and comprises a lens barrel, a mounting ring coaxial with the lens barrel is fixed on the left side of the lens barrel, and a second lens, a third lens and a fourth lens are sequentially and movably connected on the inner side of the lens barrel from right to left. A first lens is fixed on the inner side of the lens barrel and located on the right side of the second lens, and adjusting assemblies which penetrate through the side wall of the lens barrel and can achieve continuous zooming are arranged on the outer sides of the second lens, the third lens and the fourth lens. The low-cost large-target-surface infrared continuous zoom lens is suitable for a large-target-surface detector with the resolution ratio of 1280 * 1024, the total number of lenses of the lens is small, the total number of the lenses is four, the lenses of the lens are made of three chalcogenide glass and one germanium glass, and the diffraction surface is not on the lens with the large diameter. And by using the adjusting assembly, the focal length adjusting effect can be ensured, the structure is relatively simple, and the cost can be effectively reduced.

Description

Technical Field

[0001] The utility model relates to the technical field of optical lenses, in particular to a low-cost large-target-surface infrared continuous zoom lens. Background Art

[0002] In recent years, with the development of science and technology, infrared lenses have been widely used in various fields. Compared with infrared fixed-focus lenses, infrared continuous zoom lenses can search, track and aim at targets. When switching between large and small fields of view, they can maintain image stability and continuity. The target image will not be lost and can remain clear. It has the advantages of taking into account both large field of view search and small field of view recognition at the same time, and is widely used in security monitoring, search and tracking, forest fire prevention and other fields.

[0003] For example, a Chinese patent (publication number: CN214504008U) discloses a white-light near-infrared zoom lens, which belongs to the field of zoom lenses. The white-light near-infrared zoom lens includes a main lens barrel, and also includes: an oil filling device, fixedly connected to the outer wall of the main lens barrel, the oil filling device includes a first transmission assembly and a fixed assembly; the first transmission assembly includes a first pulley, a screw, a connecting rod, a lifting plate and a second baffle, the first pulley is rotatably connected to the side wall of the fixed frame, the screw is threadedly connected to the first pulley, the connecting rod is rotatably connected to one end of the screw close to the oil tank, and the lifting plate is fixedly connected to the other end of the connecting rod; a zoom device, rotatably connected to the outer wall of the main lens barrel; a motor, fixedly connected to the outer wall of the main lens barrel; the utility model increases the smoothness of the lens zooming process, reduces the user's later maintenance costs for the lens, and avoids the lens from getting stuck during the zooming process, which causes damage to the internal components of the lens.

[0004] However, the device is expensive, the overall structure is complex, and the materials used in the lens are expensive. Both maintenance and production require high costs. Therefore, a low-cost large-target infrared continuous zoom lens is proposed to solve the above problems. Utility Model Content

[0005] In view of the shortcomings of the existing technology, the utility model provides a low-cost large-target infrared continuous zoom lens, which has the advantages of ensuring imaging effects while having low costs, and solves the problem of high costs of traditional zoom lenses.

[0006] To achieve the above objectives, the present invention provides the following technical solution: a low-cost, large-target-area infrared continuous zoom lens, comprising a lens barrel, a mounting ring coaxial with the lens barrel being fixed to the left side of the lens barrel, a second lens, a third lens, and a fourth lens being movably connected to the inner side of the lens barrel from right to left, a first lens being fixed to the inner side of the lens barrel and to the right of the second lens, and an adjustment assembly penetrating the side wall of the lens barrel and capable of achieving continuous zooming being provided on the outer sides of the second, third, and fourth lenses;

[0007] The side wall of the inner cavity of the lens barrel is provided with six strip-shaped limit grooves, three transmission grooves, six connecting grooves, six stabilizing grooves and three adjustment grooves. The opposite sides of each two limit grooves are connected to the annular transmission groove, the outer side of each transmission groove is connected to the annular adjustment groove, the left and right sides of each adjustment groove and located outside the transmission groove are respectively connected to two annular connecting grooves, and the opposite sides of the two connecting grooves are connected to the annular stabilizing groove;

[0008] Each of the adjustment components includes two limit blocks that are movably connected to the two limit grooves respectively. The opposite sides of the two limit blocks are threadedly connected to a transmission ring that is movably connected to the transmission groove. The outer side of the transmission ring is fixed with a holding ring that passes through the transmission groove and the adjustment groove in sequence and extends to the outside of the lens barrel. The left and right sides of the holding ring are provided with connecting parts that pass through the connecting groove and extend into the stabilizing groove.

[0009] Furthermore, a threaded strip is fixed on the outer surface of the mounting ring, and the inner side of the mounting ring is flush with the inner side of the lens barrel.

[0010] Furthermore, each of the connecting parts includes a connecting ring that is fixed to the gripping ring and passes through the connecting groove, and a stabilizing ring that is movably connected to the stabilizing groove is fixed on the side of the connecting ring away from the gripping ring.

[0011] Furthermore, a plurality of friction blocks for increasing friction force are fixed on the outer surface of the grip ring and located outside the lens barrel, and the side wall of each friction block is sloped.

[0012] Furthermore, the first lens is composed of a meniscus germanium lens with a convex surface facing the object side, the second lens is composed of a biconcave chalcogenide glass, the third lens is composed of a meniscus chalcogenide glass, and the fourth lens is composed of a meniscus chalcogenide glass.

[0013] Furthermore, the tops and bottoms of the second lens, the third lens and the fourth lens are all fixed to the limiting blocks, and each of the limiting blocks passes through the limiting slot and extends into the lens barrel.

[0014] Furthermore, an external thread is fixed on one side of each of the limit blocks close to the transmission ring, and an internal thread is fixed on one side of each of the transmission rings close to the limit blocks, and each of the internal threads is threadedly connected to the external thread.

[0015] Furthermore, the lens barrel is cylindrical, and each of the adjustment components is located at the same axis as the lens barrel.

[0016] Compared with the existing technology, the technical solution of this application has the following beneficial effects:

[0017] This low-cost large-target infrared continuous zoom lens is suitable for large-target detectors with a resolution of 1280*1024. The lens has a small number of lenses, with a total of four lenses. The lenses are made of three chalcogenide glasses and one germanium glass, and the diffraction surface is not on the lens with a large diameter, which can effectively control costs and reduce overall weight. The use of adjustment components can ensure the focal length adjustment effect while the structure is relatively simple, which can effectively reduce costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 This is a schematic diagram of the structure of the utility model;

[0019] Figure 2 It is a three-dimensional cross-sectional view of the connection between the lens barrel and the mounting ring of the utility model;

[0020] Figure 3 A three-dimensional cross-sectional view of the adjustment component of the present invention;

[0021] Figure 4 This is a schematic diagram of the MTF curve of a large field of view embodiment of the present utility model;

[0022] Figure 5 Schematic diagram of the MTF curve of a small field of view of an embodiment of the present utility model;

[0023] Figure 6 This is a schematic diagram of field curvature and distortion of a large field of view according to an embodiment of the present utility model;

[0024] Figure 7 Schematic diagram of field curvature and distortion of a small field of view according to an embodiment of the present invention.

[0025] In the figure: 1 lens barrel, 2 mounting ring, 3 adjustment assembly, 301 limit block, 302 transmission ring, 303 holding ring, 304 connecting part, 3041 connecting ring, 3042 stabilizing ring, 4 first lens, 5 second lens, 6 third lens, 7 fourth lens. DETAILED DESCRIPTION

[0026] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0027] See also Figures 1 to 2In this embodiment, a low-cost, large-target-area infrared continuous zoom lens includes a lens barrel 1. A mounting ring 2 coaxial with the lens barrel 1 is fixed to the left side of the lens barrel 1. The mounting ring 2 is used to fix the lens to a subsequent imaging device, ensuring the stability of the connection while facilitating disassembly. A second lens 5, a third lens 6, and a fourth lens 7 are movably connected to the inner side of the lens barrel 1 from right to left. A first lens 4 is fixed to the inner side of the lens barrel 1 and to the right of the second lens 5. An adjustment component 3 that penetrates the side wall of the lens barrel 1 and can achieve continuous zoom is provided on the outer sides of the second lens 5, the third lens 6, and the fourth lens 7. The adjustment component 3 can control the movement of the second lens 5, the third lens 6, and the fourth lens 7, thereby achieving a continuous zoom effect.

[0028] In addition, six strip-shaped limit grooves, three transmission grooves, six connecting grooves, six stabilizing grooves and three adjustment grooves are provided on the side wall of the inner cavity of the lens barrel 1. The opposite sides of each two limit grooves are connected to the annular transmission groove, and the outer side of each transmission groove is connected to the annular adjustment groove. The left and right sides of each adjustment groove and the outer side of the transmission groove are respectively connected to two annular connecting grooves, and the opposite sides of the two connecting grooves are connected to the annular stabilizing groove. They can improve the overall stability of the adjustment component 3 while ensuring the smooth rotation of the adjustment component 3.

[0029] It can be known that a threaded strip is fixed on the outer surface of the mounting ring 2, which can conveniently and quickly connect or disconnect the lens from the imaging device, ensuring the stability of the connection while facilitating the replacement of different lenses. The inner side of the mounting ring 2 is flush with the inner side of the lens barrel 1, which can ensure the imaging effect.

[0030] In this embodiment, the overall structure of the device is simple, and the second lens 5, the third lens 6 and the fourth lens 7 are all made of chalcogenide glass. Chalcogenide glass is less expensive than germanium-based glass, which can effectively reduce the overall production cost and subsequent maintenance cost.

[0031] Please refer again Figure 1 and Figure 3 In order to reduce costs while ensuring the zoom effect, each adjustment assembly 3 in this embodiment includes two limit blocks 301 that are movably connected to the two limit grooves respectively. When the limit blocks 301 are driven by the transmission ring 302 to move, they can smoothly drive the lens to move, thereby achieving the effect of changing the focal length. The opposite sides of the two limit blocks 301 are threadedly connected to the transmission ring 302 that is movably connected to the transmission groove. The outer side of the transmission ring 302 is fixed with a holding ring 303 that passes through the transmission groove and the adjustment groove in sequence and extends to the outside of the lens barrel 1. When adjustment is needed, the adjustment can be completed by directly rotating the holding ring 303. Both the left and right sides of the holding ring 303 are provided with connecting parts 304 that pass through the connecting groove and extend to the stabilizing groove.

[0032] It can be known that the lens barrel 1 is cylindrical, and each adjustment component 3 is located on the same axis as the lens barrel 1. The coaxiality of the adjustment component 3 and the lens barrel 1 can improve the stability of the overall adjustment. Each limit block 301 is fixed with an external thread on the side close to the transmission ring 302, and each transmission ring 302 is fixed with an internal thread on the side close to the limit block 301. Each internal thread is threadedly connected to the external thread. The threaded connection and the limit groove cooperate to ensure that the limit block 301 smoothly converts the rotational power into the moving power, thereby driving the lens to move.

[0033] In addition, each connecting portion 304 includes a connecting ring 3041 that is fixed to the holding ring 303 and passes through the connecting groove. The connecting ring 3041 serves to connect the stabilizing ring 3042. The stabilizing ring 3042 cooperates with the stabilizing groove to achieve a good connection effect, thereby improving the overall stability of the adjustment assembly 3. A stabilizing ring 3042 that is movably connected to the stabilizing groove is fixed on the side of the connecting ring 3041 away from the holding ring 303.

[0034] Furthermore, a plurality of friction blocks are fixed on the outer surface of the grip ring 303 and located outside the lens barrel 1 to increase friction. The friction blocks are used to increase friction and facilitate the user to rotate the grip ring 303. The sidewalls of each friction block are sloped. The first lens 4 is composed of a meniscus germanium lens with a convex surface facing the object side, the second lens 5 is composed of a biconcave chalcogenide glass, and the third lens 6 is composed of a meniscus chalcogenide glass. The first lens 4 has a positive refractive power, the second lens 5 has a negative refractive power, and the third lens 6 has a positive refractive power. The fourth lens 7 has positive refractive power and is composed of a meniscus-type chalcogenide glass. The top and bottom of the second lens 5, the third lens 6 and the fourth lens 7 are fixed to the limit block 301. Each limit block 301 passes through the limit groove and extends into the lens barrel 1. The focal length of the first lens 4 must be greater than 50 mm, the focal length of the second lens 5 must be between 10 mm and 100 mm, the focal length of the third lens 6 must be between 30 mm and 100 mm, and the focal length of the fourth lens 7 must be greater than 50 mm.

[0035] In this embodiment, the transmission ring 302 can be controlled to rotate by rotating the holding ring 303, which further drives the limit block 301 to move, thereby driving the lens to move and change the focal length. The movement of the three lenses can achieve a continuous zoom effect.

[0036] See also Figures 4 to 7 To further illustrate the imaging effect, the Figures 4 to 5 The horizontal axis represents the spatial frequency of line pairs / mm, and the vertical axis represents the MTF value. The resolution required to achieve 42 line pairs with a 1280x1024 (12μm) detector is given by Figures 4 to 5It can be clearly seen that the infrared optical system has been well compensated for various aberrations. Figures 6 to 7 It can be clearly seen that the imaging curvature is good and the distortion is small.

[0037] It can be understood that this lens can ensure the imaging effect while effectively reducing the cost and weight, and can be better applied to optoelectronic systems with high weight requirements. In addition, the continuous zoom of this lens is stable and smooth, which can effectively improve the imaging quality.

[0038] The working principle of the above embodiment is:

[0039] When the focal length needs to be adjusted, the second lens 5, the third lens 6 and the fourth lens 7 can be controlled separately by rotating the three holding rings 303 to achieve the effect of continuous zoom, thereby realizing switching between a large field of view and a small field of view. The holding ring 303 is held and rotated, and the power is transmitted to the transmission ring 302 through the holding ring 303. Due to the limitation of the limit groove, the limit block 301 will not rotate with the transmission ring 302, but will move, thereby achieving the effect of adjusting the focal length of the lens. The first lens 4 is a meniscus germanium lens with the convex surface facing the object side, and the second lens 5, the third lens 6 and the fourth lens 7 are all chalcogenide glass, which can reduce the overall weight and can be applied to optoelectronic systems with high weight requirements while also effectively controlling costs.

[0040] It should be noted that, in this document, relational terms such as first and second, etc., are used only to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply the existence of any such actual relationship or order between these entities or operations. Moreover, the terms "comprises," "comprising," or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article, or device comprising a series of elements includes not only those elements, but also other elements not explicitly listed, or elements inherent to such process, method, article, or device. In the absence of further limitations, an element defined by the phrase "comprising a ..." does not exclude the presence of other identical elements in the process, method, article, or device comprising the element.

[0041] Although the embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to these embodiments without departing from the principles and spirit of the present invention.

Claims

1. A low-cost, large-area infrared continuous zoom lens, comprising a lens barrel (1), characterized in that: A mounting ring (2) coaxial with the lens barrel (1) is fixed on the left side of the lens barrel (1); a second lens (5), a third lens (6) and a fourth lens (7) are movably connected in sequence from right to left on the inner side of the lens barrel (1); a first lens (4) is fixed on the inner side of the lens barrel (1) and on the right side of the second lens (5); and an adjustment component (3) penetrating the side wall of the lens barrel (1) and capable of achieving continuous zoom is provided on the outer sides of the second lens (5), the third lens (6) and the fourth lens (7); The inner cavity side wall of the lens barrel (1) is provided with six strip-shaped limiting grooves, three transmission grooves, six connecting grooves, six stabilizing grooves and three adjusting grooves. The opposite sides of each two limiting grooves are connected to the annular transmission groove. The outer side of each transmission groove is connected to the annular adjusting groove. The left and right sides of each adjusting groove and the outer side of the transmission groove are respectively connected to two annular connecting grooves. The opposite sides of the two connecting grooves are connected to the annular stabilizing groove. Each of the adjustment components (3) comprises two limit blocks (301) movably connected to the two limit slots respectively; a transmission ring (302) movably connected to the transmission slot is threadedly connected to the opposite sides of the two limit blocks (301); a gripping ring (303) is fixed on the outer side of the transmission ring (302), which passes through the transmission slot and the adjustment slot in sequence and extends to the outside of the lens barrel (1); and a connecting portion (304) is provided on both the left and right sides of the gripping ring (303), which passes through the connection slot and extends to the inside of the stabilizing slot.

2. The low-cost, large-area infrared continuous zoom lens according to claim 1, characterized in that: A threaded strip is fixed on the outer surface of the mounting ring (2), and the inner side of the mounting ring (2) is flush with the inner side of the lens barrel (1).

3. The low-cost, large-area infrared continuous zoom lens according to claim 1, characterized in that: Each of the connecting parts (304) includes a connecting ring (3041) fixed to the gripping ring (303) and passing through the connecting groove. A stabilizing ring (3042) movably connected to the stabilizing groove is fixed on the side of the connecting ring (3041) away from the gripping ring (303).

4. The low-cost, large-area infrared continuous zoom lens according to claim 1, characterized in that: A plurality of friction blocks for increasing friction force are fixed on the outer surface of the gripping ring (303) and located outside the lens barrel (1), and the side wall of each friction block is sloped.

5. The low-cost, large-area infrared continuous zoom lens according to claim 1, characterized in that: The first lens (4) is composed of a meniscus germanium lens with a convex surface facing the object side, the second lens (5) is composed of a biconcave chalcogenide glass, the third lens (6) is composed of a meniscus chalcogenide glass, and the fourth lens (7) is composed of a meniscus chalcogenide glass.

6. The low-cost, large-area infrared continuous zoom lens according to claim 1, characterized in that: The tops and bottoms of the second lens (5), the third lens (6) and the fourth lens (7) are all fixed to the limiting blocks (301), and each limiting block (301) passes through the limiting slot and extends into the lens barrel (1).

7. The low-cost, large-area infrared continuous zoom lens according to claim 1, characterized in that: An external thread is fixed on one side of each of the limit blocks (301) close to the transmission ring (302), and an internal thread is fixed on one side of each of the transmission rings (302) close to the limit block (301), and each of the internal threads is threadedly connected to the external thread.

8. The low-cost, large-area infrared continuous zoom lens according to claim 1, characterized in that: The lens barrel (1) is cylindrical, and each of the adjustment components (3) is located on the same axis as the lens barrel (1).

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