F4.5mm compact infrared lens and its assembly method

Abstract

The present invention relates to an F4.5mm compact infrared lens, which is characterized by comprising a lens barrel, wherein a negative crescent lens A, a positive crescent lens B, and a biconvex lens C are sequentially arranged in the lens barrel along the incident direction of light from left to right, the air interval between the negative crescent lens A and the positive crescent lens B is 14.61mm, the air interval between the positive crescent lens B and the biconvex lens C is 8.85mm, and the air interval between the biconvex lens C and the image plane is 8.21mm. The lens has a compact structure, a short lens structure length, is easy to carry, and has a high transmittance. In the optical design, the optical focal length is reasonably allocated to achieve the optical athermal characteristics of temperature self-adaptation, and can be adapted to a long-wave infrared non-cooling 384×288, 17μm detector to perform real-time recording and monitoring tasks. The production cost is low and it is suitable for large-scale production.

Description

Technical Field

[0001] The invention relates to an F4.5mm compact infrared lens and an assembling method thereof. Background Art

[0002] With the development of science and technology, infrared imaging technology has been widely used in defense, industry, medical and other fields. Infrared detection has a certain ability to penetrate smoke, fog, haze, snow and other fields, as well as the ability to identify camouflage. It is not blinded by strong light or flash on the battlefield, and can achieve long-distance and all-weather observation, especially suitable for target detection at night and under adverse weather conditions.

[0003] Temperature not only affects the refractive index of optical materials, but also causes thermal expansion and contraction of the lens barrel material, resulting in changes in optical power and shifting of the best image plane. This reduces the quality of optical imaging, blurs the image, reduces contrast, and ultimately affects the imaging performance of the lens. Since the temperature coefficient of the refractive index of infrared optical materials is large, drastic changes in operating temperature will have a serious impact on the infrared optical system. In order to adapt to special applications, the lens is also required to be temperature-adaptive and portable. Summary of the invention

[0004] In view of the deficiencies in the prior art, the technical problem to be solved by the present invention is to provide a F4.5mm compact infrared lens and an assembly method thereof.

[0005] In order to solve the above technical problems, the technical solution of the present invention is: an F4.5mm compact infrared lens, including a lens barrel, in which a negative meniscus lens A, a positive meniscus lens B, and a biconvex lens C are arranged in sequence along the incident direction of light from left to right, the air gap between the negative meniscus lens A and the positive meniscus lens B is 14.61mm, the air gap between the positive meniscus lens B and the biconvex lens C is 8.85mm, and the air gap between the biconvex lens C and the image plane is 8.21mm.

[0006] Preferably, the lens barrel comprises an outer cover, and a main barrel and a main lens barrel which are sequentially arranged in the outer cover.

[0007] Preferably, the negative meniscus lens A is installed on the inner wall of the front end of the main lens barrel, and an A-plate pressure ring is provided on the front side of the negative meniscus lens A. The positive meniscus lens B and the biconvex lens C are installed on the inner wall of the rear end of the main lens barrel, and a B-plate pressure ring is provided on the rear side of the positive meniscus lens B, and a rear pressure ring is provided on the rear side of the biconvex lens C.

[0008] The invention discloses an assembly method of a F4.5mm compact infrared lens, which is performed according to the following steps: a negative meniscus lens A is installed from the front end of a main lens barrel and fixed by an A-piece pressing ring, and shellac is used to seal between the A-piece pressing ring and the negative meniscus lens A; a positive meniscus lens B, a B-piece pressing ring, and a double convex lens C are assembled from the rear end of the main lens barrel in sequence and fixed by the B-piece pressing ring.

[0009] Compared with the prior art, the present invention has the following beneficial effects: compact structure, short lens structure length, easy to carry, high transmittance, reasonable distribution of optical focal length in optical design, realization of temperature-adaptive optical athermalization, and can be adapted to long-wave infrared non-cooled 384×288, 17μm detectors for real-time recording and monitoring tasks. The production cost is low and suitable for large-scale production.

[0010] The present invention is further described in detail below with reference to the accompanying drawings and specific embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] Figure 1 Schematic diagram of the structure of an embodiment of the present invention.

[0012] Figure 2 Schematic diagram of the optical system.

[0013] In the figure:

[0014] 1-main tube, 2-outer cover, 3-telescopic ring 1, 4-countersunk screw, 5-fixing part, 6-telescopic ring 2, 7-elastic gasket, 8-limiting pressure ring, 9-negative crescent lens A, 10-A plate pressure ring, 11-main lens tube, 12-positive crescent lens B, 13-B plate pressure ring, 14-rear pressure ring, 15-double convex lens C. DETAILED DESCRIPTION

[0015] In order to make the above features and advantages of the present invention more clearly understood, embodiments are given below with reference to the accompanying drawings for detailed description.

[0016] like Figure 1~2 As shown, a F4.5mm compact infrared lens comprises a lens barrel, in which a negative meniscus lens A, a positive meniscus lens B, and a biconvex lens C are sequentially arranged along the incident direction of light from left to right. The air gap between the negative meniscus lens A and the positive meniscus lens B is 14.61mm, the air gap between the positive meniscus lens B and the biconvex lens C is 8.85mm, and the air gap between the biconvex lens C and the image plane is 8.21mm.

[0017] In the embodiment of the present invention, the lens barrel includes an outer cover, a main barrel and a main lens barrel which are sequentially arranged in the outer cover.

[0018] In the embodiment of the present invention, the negative meniscus lens A is installed on the inner wall of the front end of the main lens barrel, and an A-plate pressing ring is arranged on the front side of the negative meniscus lens A. The positive meniscus lens B and the biconvex lens C are installed on the inner wall of the rear end of the main lens barrel, and a B-plate pressing ring is arranged on the rear side of the positive meniscus lens B, and a rear pressing ring is arranged on the rear side of the biconvex lens C.

[0019] In the embodiment of the present invention, the negative meniscus lens A is limited by the front end of the main lens barrel, and the A-piece pressure ring and the negative meniscus lens A are sealed with shellac, which has good sealing performance.

[0020] In the embodiment of the present invention, a series of measures are taken to improve the vibration and impact resistance of the lens while ensuring a compact structure, and a structure with two front and rear lens barrels is adopted to ensure the use requirements of the system.

[0021] In the embodiment of the present invention, the countersunk screw is used to limit the position, and the lens can be manually focused within a specified movement range by rotating the outer cover, which is simpler and more convenient.

[0022] In the embodiment of the present invention, the main lens barrel and the main tube are threadedly matched, and a component which is easy to rotate and consists of a telescopic ring 1, a fixing piece and a telescopic ring 2 is arranged between the main lens barrel and the main tube, and the main tube is threadedly matched with the outer cover.

[0023] In the embodiment of the present invention, optical athermalization utilizes the difference between the characteristics of optical materials in the optical design, and eliminates the influence of temperature by combining characteristic materials, thereby ensuring stable image quality within a large temperature range and achieving optical athermalization.

[0024] The invention discloses an assembly method of an F4.5mm compact infrared lens, which is carried out according to the following steps: a telescopic ring 2, a fixing member and a telescopic ring 1 are sequentially assembled into a main lens barrel, the main lens barrel is then assembled into the main barrel and fixed by an elastic gasket limit pressure ring, an outer cover is connected to the main barrel by a thread and assembled with a countersunk screw; a negative crescent lens A is installed from the front end of the main lens barrel and fixed by an A-piece pressure ring, and shellac is used to seal between the A-piece pressure ring and the negative crescent lens A; a positive crescent lens B, a B-piece pressure ring and a double convex lens C are sequentially assembled from the rear end of the main lens barrel and fixed by the B-piece pressure ring. Such assembly is conducive to reducing the difficulty of assembly, improving the assembly efficiency and facilitating the debugging of the lens. Shellac is dotted on all the threaded mating places between the outer cover and the lens barrel, and this method is conducive to improving the vibration resistance and impact resistance of the optical lens part and improving the anti-seismic performance of the overall lens.

[0025] In this embodiment, the optical structure formed by the above lens group achieves the following optical indicators:

[0026] Working band: 8μm-12μm;

[0027] Focal length: f′=4.5mm;

[0028] Detector: Long-wave infrared uncooled type 384×288, 17μm;

[0029] Field of view: 79.44°×60.86°;

[0030] Relative aperture D / f′: 1.0;

[0031] The specific parameters of each lens are as follows:

[0032]

[0033] The present invention is not limited to the above-mentioned best implementation mode. Anyone can derive other various forms of F4.5mm compact infrared lens and its assembly method under the enlightenment of the present invention. All equivalent changes and modifications made according to the scope of the patent application of the present invention shall fall within the scope of the present invention.

Claims

1. A F4.5mm compact infrared lens, characterized by: The invention comprises a lens barrel, wherein a negative meniscus lens A, a positive meniscus lens B, and a biconvex lens C are sequentially arranged in the lens barrel along the incident direction of light from left to right, the air interval between the negative meniscus lens A and the positive meniscus lens B is 14.61 mm, the air interval between the positive meniscus lens B and the biconvex lens C is 8.85 mm, and the air interval between the biconvex lens C and the image plane is 8.21 mm; the lens barrel comprises an outer cover, and a main barrel and a main lens barrel sequentially arranged in the outer cover; the negative meniscus lens A is mounted on the inner wall of the front end of the main lens barrel, an A-piece pressure ring is arranged on the front side of the negative meniscus lens A, the positive meniscus lens B and the biconvex lens C are mounted on the inner wall of the rear end of the main lens barrel, a B-piece pressure ring is arranged on the rear side of the positive meniscus lens B, and a rear pressure ring is arranged on the rear side of the biconvex lens C; the curvature radius of the negative meniscus lens A toward the object side is 14.97 mm, the curvature radius toward the image side is 9.71 mm, the curvature radius of the positive meniscus lens B toward the object side is 32.89 mm, the curvature radius of the lens facing the image side is 30.29 mm, the curvature radius of the biconvex lens C facing the object side is 64.77 mm, and the curvature radius of the lens facing the image side is 42.68 mm; the center thickness of the negative crescent lens A is 2.91 mm, the center thickness of the positive crescent lens B is 2.82 mm, and the center thickness of the biconvex lens C is 4.35 mm; the working band of the lens: 8μm-12μm; focal length: f′=4.5mm; lens detector: long-wave infrared uncooled type 384×288, 17μm; field of view: 79.44°×60.86°; relative aperture D / f′: 1.0; The assembly method of the F4.5mm compact infrared lens is carried out in the following steps: a negative meniscus lens A is installed from the front end of the main lens barrel and fixed by the A-piece pressing ring, and the A-piece pressing ring and the negative meniscus lens A are sealed with shellac; a positive meniscus lens B, a B-piece pressing ring, and a double convex lens C are assembled from the rear end of the main lens barrel in sequence and fixed by the B-piece pressing ring.

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