Low-cost large-target-surface infrared double-view-field lens

Abstract

The utility model relates to a low-cost large-target-surface infrared double-view-field lens, which belongs to the technical field of optical lenses and comprises a shell, an optical system assembly is arranged in the shell, and a round bin is fixed on the front wall of the shell. The optical system assembly comprises a first lens fixed to the left end of the inner cavity of the shell and further comprises a second lens sliding in the shell. The low-cost large-target-surface infrared double-field-of-view 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 lens is provided with four lenses, the lenses of the lens adopt chalcogenide glass with relatively low price to replace most of germanium glass with high price, the cost of the infrared double-field-of-view lens can be greatly reduced, and the large-target-surface infrared double-field-of-view lens is suitable for large-target-surface detectors with the resolution ratio of 1280 * 1024. And the density of chalcogenide glass adopted by the lens is smaller than that of germanium glass, so that the weight can be reduced, the infrared double-view-field lens can be better applied to a photoelectric system with high weight requirement, and meanwhile, the infrared double-view-field lens can be switched between a short-focus large view field and a long-focus small view field.

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 dual-field-of-view lens. Background Art

[0002] With the advancement of science and technology in recent years, infrared lenses have been widely used in various fields. Common infrared lenses include fixed-focus infrared lenses and zoom infrared lenses. Among these, zoom infrared lenses include continuous zoom infrared lenses and dual-field infrared lenses. Dual-field infrared lenses offer advantages such as simple structure, compact size, and high transmittance. They can perform large-field search and precise identification within a small field of view. They also offer fast field-of-view changes and are less likely to lose sight of the target. However, currently used dual-field infrared lenses in China generally suffer from drawbacks such as a large number of lenses and the use of expensive germanium glass as the primary lens material. Furthermore, detector resolutions are generally limited to 640*512 pixels. With the advancement of infrared detector technology, the development and design of a low-cost, large-area infrared dual-field infrared lens is becoming increasingly important.

[0003] In existing technical reports, Chinese patent (CN 212379655 U) discloses a lightweight, uncooled long-wave infrared dual-field-of-view lens. This lens uses five lenses, four of which are made of expensive germanium glass, resulting in high cost, and the detector resolution is 640*512. Chinese patent CN 118688943 A discloses a dual-field-of-view infrared zoom lens and infrared thermal imaging system. This lens uses four lenses, but all four lenses are made of expensive germanium glass, resulting in high cost, and the detector resolution is also 640*512, resulting in high cost. Utility Model Content

[0004] In view of the shortcomings of the existing technology, the utility model provides a low-cost large-target infrared dual-field-of-view lens, which has the advantages of low cost and solves the problem of high cost.

[0005] To achieve the above object, the present invention provides the following technical solution: a low-cost large-target-area infrared dual-field-of-view lens, comprising a housing, an optical system component is disposed inside the housing, and a circular silo is fixed to the front wall of the housing;

[0006] The optical system assembly includes a first lens fixed to the left end of the inner cavity of the shell, the optical system assembly also includes a second lens sliding inside the shell, the optical system assembly also includes a third lens and a fourth lens respectively fixed to the right end of the inner cavity of the shell, the optical system assembly also includes a detector window fixed to the right side wall of the shell, an image plane is fixed to the inner side of the detector window, and the optical system assembly also includes an adjustment structure arranged at the front end of the second lens.

[0007] Furthermore, the first lens is a meniscus germanium lens with a convex surface facing the object side, the second lens is a biconcave chalcogenide glass, and the third lens and the fourth lens are both meniscus chalcogenide glasses.

[0008] Furthermore, the focal length of the first lens is 204.7 mm, the focal length of the second lens is -64.3 mm, the focal length of the third lens is 57.8 mm, and the focal length of the fourth lens is 1201.1 mm.

[0009] Furthermore, the adjustment structure includes an adjustment block fixed to the front end of the second lens, and the adjustment structure also includes a screw rotatably connected to the left and right walls of the inner cavity of the circular warehouse through bearings, a worm gear is fixed to the outer surface of the screw, a worm is engaged with the rear end of the worm gear, and an operating block is fixed to the top end of the worm.

[0010] Furthermore, a wall of the shell opposite to the silo is provided with a sliding hole for the adjustment block to pass through and slide inside the wall.

[0011] Furthermore, a threaded hole for a screw to pass through is opened on the right side wall of the adjustment block, and the screw is threadedly connected to the inner side of the threaded hole.

[0012] Furthermore, a rotating hole is provided at the top of the silo for the worm to pass through and rotate inside.

[0013] Compared with the existing technology, the technical solution of this application has the following beneficial effects:

[0014] This low-cost, large-target infrared dual-field-of-view 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 lens lenses use relatively low-priced chalcogenide glass instead of most expensive germanium glass, which can greatly reduce the cost of the infrared dual-field-of-view lens. In addition, the density of the chalcogenide glass used in the lens lenses is lower than that of germanium glass, which can reduce weight and thus be better used in optoelectronic systems with high weight requirements. At the same time, the infrared dual-field-of-view lens switches between short-focus large field of view and long-focus small field of view. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 This is a schematic diagram of the structure of the utility model;

[0016] Figure 2 This is a schematic diagram of the structure of the shell and the round silo of the utility model;

[0017] Figure 3 This is a schematic diagram of the internal structure of the circular silo of the utility model;

[0018] Figure 4 This is an optical schematic diagram of the large field of view of the low-cost, large-target-area infrared dual-field-of-view lens of the utility model;

[0019] Figure 5 This is an optical schematic diagram of the small field of view of the low-cost, large-target infrared dual-field lens of the utility model;

[0020] Figure 6 This is a schematic diagram of the MTF curve of the utility model with a large field of view;

[0021] Figure 7 Schematic diagram of the MTF curve of the small field of view of the utility model;

[0022] Figure 8 Schematic diagram of field curvature and distortion of the large field of view of the present invention;

[0023] Figure 9 Schematic diagram of field curvature and distortion of a small field of view of the present invention.

[0024] In the figure: 1 housing, 21 first lens, 22 second lens, 221 adjustment block, 222 round silo, 223 screw, 224 worm gear, 225 worm, 226 operating block, 23 third lens, 24 fourth lens, 25 detector window, 26 image plane. DETAILED DESCRIPTION

[0025] 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.

[0026] See also Figures 1 to 2 In this embodiment, a low-cost, large-target-area infrared dual-field-of-view lens includes a housing 1, an optical system component is provided inside the housing 1, and a circular silo 222 is fixed to the front wall of the housing 1.

[0027] See also Figures 1 to 9 The optical system assembly in this embodiment includes a first lens 21 fixed to the left end of the inner cavity of the shell 1, the optical system assembly also includes a second lens 22 sliding inside the shell 1, the optical system assembly also includes a third lens 23 and a fourth lens 24 respectively fixed to the right end of the inner cavity of the shell 1, the optical system assembly also includes a detector window 25 fixed to the right side wall of the shell 1, and an image plane 26 is fixed to the inner side of the detector window 25. The optical system assembly also includes an adjustment structure arranged at the front end of the second lens 22.

[0028] The first lens 21 is a meniscus-shaped germanium lens with a convex surface facing the object side and having positive refractive power. The second lens 22 is a biconcave chalcogenide glass lens with negative refractive power. The third lens 23 and the fourth lens 24 are both meniscus-shaped chalcogenide glass lenses with positive refractive power. The number of lenses used is relatively small, and relatively inexpensive chalcogenide glass is used instead of most expensive germanium glass. This can significantly reduce the cost of infrared dual-field-of-view lenses. Furthermore, the density of chalcogenide glass is lower than that of germanium glass, which can reduce weight and thus be better used in optoelectronic systems with high weight requirements.

[0029] In addition, the focal length of the first lens 21 is 204.7, and its focal length ratio to the entire lens satisfies: f1>50, f1 is the first lens 21, the focal length of the second lens 22 is -64.3mm, and its focal length ratio to the entire lens satisfies: 10<f2<100, f2 is the second lens 22, the focal length of the third lens 23 is 57.8mm, and its focal length ratio to the entire lens satisfies: 30<f3<100, f3 is the third lens 23, the focal length of the fourth lens 24 is 1201.1mm, and its focal length ratio to the entire lens satisfies: f4>50, f4 is the fourth lens 24, so that it can be used in a large target surface detector with a resolution of 1280*1024.

[0030] In addition, a system aperture ST is provided on the left side wall of the third lens 23 and is fixed to the inner wall of the housing 1. From the object side to the imaging side, it includes the first lens 21, the second lens 22, the system aperture ST, the third lens 23, the fourth lens 24, the detector window 25 and the image plane 26 in sequence.

[0031] Meanwhile, the first lens 21 and the fourth lens 24 are both aspherical surfaces, and the second lens 22 and the third lens 23 are both diffraction surfaces and aspherical surfaces.

[0032] Furthermore, a fixing hole is formed on the right side wall of the housing 1 , and the detector window 25 is fixed inside the fixing hole.

[0033] See also Figures 1 to 3 The adjustment structure in this embodiment includes an adjustment block 221 fixed to the front end of the second lens 22, and the adjustment structure also includes a screw 223 rotatably connected to the left and right walls of the inner cavity of the circular warehouse 222 through bearings. A worm gear 224 is fixed to the outer surface of the screw 223, and a worm 225 is engaged with the rear end of the worm gear 224. An operating block 226 is fixed to the top of the worm 225.

[0034] Secondly, a sliding hole is provided on the wall opposite to the circular silo 222 for the adjustment block 221 to pass through and slide inside, so that the adjustment block 221 can be connected to the second lens 22 so as to adjust the position of the second lens 22, thereby changing the device to a large field of view or a small field of view.

[0035] At the same time, a threaded hole for the screw 223 to pass through is opened on the right side wall of the adjusting block 221, and the screw 223 is threadedly connected to the inner side of the threaded hole so that the screw 223 can be threadedly connected to the adjusting block 221 through the threaded hole, thereby enabling the screw 223 to drive the adjusting block 221 to move.

[0036] In addition, a rotation hole is provided at the top of the silo 222 for the worm 225 to pass through and rotate inside, so that the worm 225 can be connected to the operating block 226, thereby driving it to rotate.

[0037] The working principle of the above embodiment is:

[0038] When in use, by adopting a first lens 21 of a meniscus-type germanium lens with the convex surface facing the object side, a second lens 22 of a biconcave chalcogenide glass, and a third lens 23 and a fourth lens 24 of a meniscus-type chalcogenide glass, the number of lenses used can be reduced, which can greatly reduce the cost of the infrared dual-field-of-view lens. It is also suitable for large-target detectors with a resolution of 1280*1024.

[0039] The operating block 226 is rotated to drive the worm 225 to rotate, and the worm 225 engages with the worm wheel 224, so that the worm wheel 224 drives the screw 223 to rotate, and the screw 223 can drive the adjustment block 221 to move in the housing 1. The adjustment block 221 can drive the second lens 22 to move so that it is close to the first lens 21, and the field of view becomes larger. Conversely, when it is close to the third lens 23, the field of view becomes smaller, so as to have a dual field of view.

[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 understood 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, and the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A low-cost, large-area infrared dual-field-of-view lens, comprising a housing (1), characterized in that: An optical system component is provided inside the housing (1), and a round bin (222) is fixed to the front wall of the housing (1); The optical system assembly comprises a first lens (21) fixed to the left end of the inner cavity of the housing (1), the optical system assembly further comprises a second lens (22) sliding inside the housing (1), the optical system assembly further comprises a third lens (23) and a fourth lens (24) respectively fixed to the right end of the inner cavity of the housing (1), the optical system assembly further comprises a detector window (25) fixed to the right side wall of the housing (1), an image plane (26) is fixed inside the detector window (25), and the optical system assembly further comprises an adjustment structure arranged at the front end of the second lens (22).

2. The low-cost, large-area infrared dual-field-of-view lens according to claim 1, characterized in that: The first lens (21) is a meniscus germanium lens with a convex surface facing the object side, the second lens (22) is a biconcave chalcogenide glass, and the third lens (23) and the fourth lens (24) are both meniscus chalcogenide glasses.

3. The low-cost, large-area infrared dual-field-of-view lens according to claim 1, characterized in that: The focal length of the first lens (21) is 204.7 mm, the focal length of the second lens (22) is -64.3 mm, the focal length of the third lens (23) is 57.8 mm, and the focal length of the fourth lens (24) is 1201.1 mm.

4. The low-cost, large-area infrared dual-field-of-view lens according to claim 1, characterized in that: The adjustment structure comprises an adjustment block (221) fixed to the front end of the second lens (22), and the adjustment structure further comprises a screw (223) rotatably connected to the left and right walls of the inner cavity of the circular silo (222) via bearings, a worm gear (224) being fixed to the outer surface of the screw gear (223), a worm gear (225) being meshed with the rear end of the worm gear (224), and an operating block (226) being fixed to the top end of the worm gear (225).

5. The low-cost, large-area infrared dual-field-of-view lens according to claim 4, characterized in that: A sliding hole is provided on a wall of the housing (1) opposite to the round bin (222) for the adjustment block (221) to pass through and slide inside the wall.

6. The low-cost, large-area infrared dual-field-of-view lens according to claim 4, characterized in that: The right side wall of the adjusting block (221) is provided with a threaded hole for a screw rod (223) to pass through, and the screw rod (223) is threadedly connected to the inner side of the threaded hole.

7. The low-cost, large-area infrared dual-field-of-view lens according to claim 4, characterized in that: The top end of the circular bin (222) is provided with a rotation hole for the worm (225) to pass through and rotate inside.

Images