A lightweight low-light-level night vision device optical system

Abstract

The present invention discloses a lightweight low-light-level night vision device optical system, which comprises an objective lens mechanism, an image intensifier and an eyepiece mechanism. The objective lens mechanism comprises a first double convex lens, a second concave-convex lens, a double glued lens, a rear glued lens and a third concave-convex lens. The eyepiece mechanism comprises a plano-convex lens, a fourth concave-convex lens, a front double glued lens and a rear double glued lens. The lightweight structure is adopted to reduce the mass, the distortion rate is low, the imaging is clear, the structure is compact, and the device is convenient for wide range use.

Description

Technical Field

[0001] The invention relates to the technical field of optical systems, and in particular to a lightweight low-light-level night vision device optical system. Background Art

[0002] Night vision goggles are a type of optoelectronic technology that uses optoelectronic imaging devices to achieve nighttime observation. Night vision technologies include low-light-level night vision and infrared night vision. Low-light-level night vision technology is also known as image enhancement technology, which is a night vision goggles with an image intensifier. Photoelectric technology that enhances the faint target image illuminated by night sky light for observation. Low-light-level night vision goggles are the night vision equipment with the largest production and equipment volume and the most extensive uses at home and abroad. They can be divided into direct observation and indirect observation. The main application scenarios of low-light-level night vision goggles are military requirements, customs inspections, and outdoor hobbies. There are currently three more advanced night vision goggles: one is a low-light-level binocular eyepiece with a fixed eye distance, which shares an eyepiece end image plane at the eyepiece end, and uses a parallelogram prism to split light to both eyes, so that the number of lenses in the eyepiece system can be halved, but only a parallelogram prism is used to split light. Another is a night vision optical system, in which the eyepiece system includes a positive focal length cemented lens, a positive focal length plastic aspheric single lens, etc. Due to the use of aspheric lenses, the night vision optical system has a high cost, is difficult to debug, and is difficult to apply to civilian use; another is a military high-light low-light night vision device, which is mainly equipped with a high-light filter on the objective lens, mainly used to protect the fluorescent screen and the photocathode. This increases the cost of the entire system, and the structure is too large to be installed and used. Combining these three night vision devices, they have poor optical performance, complex structure, high cost, and a small application range. Summary of the invention

[0003] The object of the present invention is to provide a lightweight low-light-level night vision device optical system which can be used in a wide range.

[0004] To achieve the above-mentioned object, the present invention provides a lightweight low-light-level night vision device optical system, the lightweight low-light-level night vision device optical system comprising an objective lens mechanism, an image intensifier and an eyepiece mechanism, the image intensifier is detachably connected to the objective lens mechanism and is located on one side of the objective lens mechanism, the eyepiece mechanism is detachably connected to the image intensifier and is located on a side away from the objective lens mechanism;

[0005] The objective lens mechanism comprises a first shell, a first biconvex lens, a second concave-convex lens, a doublet lens, a rear doublet lens and a third concave-convex lens, the first biconvex lens is detachably connected to the first shell and is located in the first shell, the second concave-convex lens is detachably connected to the first shell and is located on one side of the first biconvex lens, the doublet lens is detachably connected to the first shell and is located away from the first biconvex lens, the rear doublet lens is detachably connected to the first shell and is located away from the second concave-convex lens, and the third concave-convex lens is detachably connected to the first shell and is located away from the doublet lens;

[0006] The eyepiece mechanism includes a second shell, a plano-convex lens, a fourth concave-convex lens, a front doublet lens and a rear doublet lens. The plano-convex lens is detachably connected to the second shell and is located on a side of the third concave-convex lens. The fourth concave-convex lens is detachably connected to the second shell and is located on a side away from the third concave-convex lens. The front doublet lens is detachably connected to the second shell and is located on a side away from the plano-convex lens. The rear doublet lens is detachably connected to the second shell and is located on a side away from the fourth concave-convex lens.

[0007] The length of the objective lens mechanism is 78.7 mm ± 0.5 mm, the focal length is 65 mm, the relative aperture is 1 / 1.38, the field of view is 10°, the wavelengths are 560 mm, 720 mm and 867 mm, and the distortion is less than 2%.

[0008] The image intensifier has a diameter of 18 mm, a magnification of 1, and an optical length of 10 mm.

[0009] The length of the eyepiece mechanism is 34 mm and the focal length is 14.5 mm.

[0010] The present invention discloses a lightweight low-light-level night vision device optical system, which comprises an objective lens mechanism, an image intensifier and an eyepiece mechanism. The objective lens mechanism comprises a first double convex lens, a second concave-convex lens, a double cemented lens, a rear cemented lens and a third concave-convex lens. The eyepiece mechanism comprises a plano-convex lens, a fourth concave-convex lens, a front double cemented lens and a rear double cemented lens. The lightweight structure is adopted to reduce the mass, the distortion rate is low, the imaging is clear, the structure is compact, and the device is convenient for wide range use. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0012] Figure 1 It is a structural schematic diagram of an optical system of a lightweight low-light-level night vision device provided by the present invention.

[0013] Figure 2 It is a structural schematic diagram of the objective lens mechanism provided by the present invention.

[0014] Figure 3 It is a structural schematic diagram of the eyepiece mechanism provided by the present invention.

[0015] 1-objective lens mechanism, 2-image intensifier, 3-eyepiece mechanism, 11-first double convex lens, 12-second concave-convex lens, 13-double cemented lens, 14-rear cemented lens, 15-third concave-convex lens, 16-first shell, 31-plano-convex lens, 32-fourth concave-convex lens, 33-front double cemented lens, 34-rear double cemented lens, 35-second shell. DETAILED DESCRIPTION

[0016] Embodiments of the present invention are described in detail below, examples of which are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are intended to be used to explain the present invention, and should not be construed as limiting the present invention.

[0017] In the description of the present invention, it should be understood that the terms "length", "width", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside" and the like indicate positions or positional relationships based on the positions or positional relationships shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention. In addition, in the description of the present invention, "multiple" means two or more, unless otherwise clearly and specifically defined.

[0018] See also Figure 1The present invention provides a lightweight low-light-level night vision device optical system, the lightweight low-light-level night vision device optical system comprises an objective lens mechanism 1, an image intensifier 2 and an eyepiece mechanism 3, the image intensifier 2 is detachably connected to the objective lens mechanism 1 and is located at one side of the objective lens mechanism 1, the eyepiece mechanism 3 is detachably connected to the image intensifier 2 and is located at a side away from the objective lens mechanism 1;

[0019] The objective lens mechanism 1 comprises a first shell 16, a first biconvex lens 11, a second concave-convex lens 12, a doublet lens 13, a rear doublet lens 14 and a third concave-convex lens 15, wherein the first biconvex lens 11 is detachably connected to the first shell 16 and is located in the first shell 16, the second concave-convex lens 12 is detachably connected to the first shell 16 and is located on one side of the first biconvex lens 11, the doublet lens 13 is detachably connected to the first shell 16 and is located away from the first biconvex lens 11, the rear doublet lens 14 is detachably connected to the first shell 16 and is located away from the second concave-convex lens 12, and the third concave-convex lens 15 is detachably connected to the first shell 16 and is located away from the doublet lens 13;

[0020] The eyepiece mechanism 3 includes a second shell 35, a plano-convex lens 31, a fourth concave-convex lens 32, a front doublet lens 33 and a rear doublet lens 34. The plano-convex lens 31 is detachably connected to the second shell 35 and is located on a side of the third concave-convex lens 15. The fourth concave-convex lens 32 is detachably connected to the second shell 35 and is located on a side away from the third concave-convex lens 15. The front doublet lens 33 is detachably connected to the second shell 35 and is located on a side away from the plano-convex lens 31. The rear doublet lens 34 is detachably connected to the second shell 35 and is located on a side away from the fourth concave-convex lens 32.

[0021] In this embodiment, the structural features of the low-light-level night vision optical system designed according to the target include, from left to right, an objective lens mechanism 1, an image intensifier 2, and an eyepiece mechanism 3. Since the image intensifier 2 is used in the low-light-level night vision optical system, the objective lens mechanism 1 and the eyepiece mechanism 3 are separated and designed. The main function of the objective lens mechanism 1 is to image the object, and the function of the eyepiece mechanism 3 is equivalent to an observation mirror. The image formed by the objective lens mechanism 1 is magnified by the image intensifier 2 and imaged at the far point position of the human eye, so that the human eye can observe more comfortably. The objective lens mechanism 1 is imaged on the image intensifier 2, undergoes photoelectric conversion, electronic enhancement, and then magnified by the eyepiece. Therefore, there is no conjugate relationship between the entrance pupil and the exit pupil in the ordinary telescopic system, so both the objective lens mechanism 1 and the eyepiece mechanism 3 need to correct the aberration separately.

[0022] The objective lens mechanism 1 comprises a first biconvex lens 11, a second concave-convex lens 12, a doublet lens 13, a rear-cemented lens 14 and a third concave-convex lens 15. Figure 2 As shown in the structural schematic diagram of the objective lens mechanism 1 provided, a double cemented lens 13 is used to correct aberrations, thereby avoiding the high cost problem caused by using an aspheric lens. The optical parameter table is shown in Table 1.

[0023] Table 1 Optical parameters of objective lens mechanism

[0024] Serial number Curvature radius R Lens center thickness Refractive index Nd Abbe number Vd FWHM 1 101.123 7.11 1.746 51.008 23.5 2 -434.25 0.2 23.5 3 43.838 6 1.671 47.281 23.5 4 72.007 0.1 23.5 5 26.036 12.74 1.622 56.951 19.5 6 -84.186 2.28 1.728 28.319 19.5 7 15.55 10 11 8 -34.2 0.82 1.622 56.951 8.5 9 24.626 6.77 1.672 32.178 8.5 10 -33.82 18 8.5 11 15.527 6.29 1.744 44.904 8.5 12 15.747 8.679 4

[0025] To ensure that the cathode surface of the image intensifier 2 obtains more light energy, the lens of the objective mechanism 1 should be coated with an anti-reflection film in the visible light to near-infrared band to match the spectral response of the image intensifier 2 to increase the transmittance of the optical system and reduce the absorption of incident light.

[0026] The function of the eyepiece mechanism 3 is to further amplify the target image formed by the objective lens mechanism 1 on the fluorescent screen of the image intensifier 2 to adapt to the human eye's observation for a longer period of time. The low-light night vision device works under low illumination conditions, so the exit pupil diameter of the eyepiece mechanism 3 is required to match the diameter of the human eye's through hole and be larger than the exit pupil diameter of a general visible light visual system. At the same time, since the main wavelength band of the fluorescent screen emission spectrum of the image intensifier 2 is mainly around 550nm, the eyepiece mechanism 3 can be regarded as a quasi-monochromatic light imaging system, and the chromatic aberration of the efficient eyepiece can be ignored. The eyepiece mechanism 3 is composed of a plano-convex lens 31, a concave-convex lens, a front double cemented lens 33, and a rear double cemented lens 34, as shown in FIG. Figure 3 The structural schematic diagram of the eyepiece mechanism 3 is shown in FIG. 2 , and the optical parameters of the eyepiece mechanism 3 are shown in Table 2.

[0027] Table 2 Optical parameters of eyepiece mechanism

[0028] Serial number Curvature radius R Lens center thickness Refractive index Nd Abbe number Vd FWHM 1 Inf 4.67 1.638 55.471 9 2 -26.931 1 9 3 -31.7 5.52 1.638 55.471 6.2 4 -13.01 1 9 5 -54.358 1.38 1.744 44.904 9 6 13.272 6.26 1.57 41.506 9 7 -19 1 9 8 19.953 1.443 1.755 27.548 9 9 11.315 6.58 1.696 55.534 9 10 46.13 5.9 9

[0029] The working distance of the eyepiece is the distance from the vertex of the front surface of the eyepiece to the fluorescent screen of the image intensifier. In order to meet the needs of myopia or hyperopia, the eyepiece should have a certain moderate adjustment ability. The size of the working distance should ensure the axial movement distance when the eyepiece diopter is adjusted. When the eyepiece diopter adjustment range is SD, the corresponding eyepiece axial movement sd is:

[0030]

[0031] The multi-piece optical structure design can effectively reduce the distortion rate of the entire optical system and best ensure the image quality. The lightweight structure design concept avoids the use of high-density glass materials in the optical design and avoids the use of metal supports in the assembly structure, thereby reducing the weight of the entire night vision device and achieving the purpose of lightweight. The structure is compact, the application range is expanded, and it can be used for night combat.

[0032] Furthermore, the length of the objective lens mechanism 1 is 78.7 mm ± 0.5 mm, the focal length is 65 mm, the relative aperture is 1 / 1.38, the field of view is 10°, the wavelengths are 560 mm, 720 mm and 867 mm, and the distortion is less than 2%.

[0033] In this embodiment, according to the image plane illumination formula, the illumination at the center of the image plane of the objective lens mechanism 1 is proportional to the square of the relative aperture of the objective lens mechanism 1. In order to obtain sufficient image plane illumination, the objective lens mechanism 1 should obtain as large a relative aperture as possible. The larger the relative aperture of the objective lens mechanism 1, the stronger the light-gathering ability. Its illumination formula satisfies the following expression:

[0034]

[0035] Where L is the brightness of the light source; θ1 and θ2 are the luminous surface dA s The angle between the normal to the illuminated surface dA and the direction of distance r.

[0036] The objective lens group is designed to have a total length of about 78.7 mm, a focal length f0′=65 mm, a relative aperture D / f0′=1 / 1.38, a field of view 2W=10°, a design wavelength of 560 nm, 720 nm, and 867 nm, and a distortion of less than 2%. The large relative aperture objective lens mechanism 1 is used in combination with the image intensifier 2, so that the image is clear, the structure is compact, and the image is easy to use.

[0037] Furthermore, the image intensifier 2 has a diameter of 18 mm, a magnification of 1, and an optical length of 10 mm.

[0038] In this embodiment, the image intensifier 2 with an effective aperture of 18 mm is used in conjunction with the objective lens mechanism 1, and has clear imaging, a compact and small structure, and is convenient for wide-range use.

[0039] Furthermore, the length of the eyepiece mechanism 3 is 34 mm and the focal length is 14.5 mm.

[0040] In this embodiment, the field of view of the eyepiece mechanism 3 is determined by the effective diameter D′ of the fluorescent screen of the image intensifier 2. c Determined together with the focal length of the eyepiece mechanism 3, the eyepiece field of view satisfies the following expression:

[0041]

[0042] The present invention discloses a lightweight low-light-level night vision device optical system, which comprises an objective lens mechanism 1, an image intensifier 2 and an eyepiece mechanism 3. The objective lens mechanism 1 comprises a first double convex lens 11, a second concave-convex lens 12, a double cemented lens 13, a rear cemented lens 14 and a third concave-convex lens 15. The eyepiece mechanism 3 comprises a plano-convex lens 31, a fourth concave-convex lens 32, a front double cemented lens 33 and a rear double cemented lens 34. The lightweight structure is adopted to reduce the mass, the distortion rate is low, the imaging is clear, the structure is compact, and the device is convenient for wide range use.

[0043] What is disclosed above is only a preferred embodiment of the present invention, and it certainly cannot be used to limit the scope of rights of the present invention. Ordinary technicians in this field can understand that all or part of the processes of the above embodiment and equivalent changes made according to the claims of the present invention still fall within the scope of the invention.

Claims

1. A lightweight low-light-level night vision device optical system, characterized in that: The optical system of the lightweight low-light-level night vision device comprises an objective lens mechanism, an image intensifier and an eyepiece mechanism, wherein the image intensifier is detachably connected to the objective lens mechanism and is located at one side of the objective lens mechanism, and the eyepiece mechanism is detachably connected to the image intensifier and is located at a side away from the objective lens mechanism; The objective lens mechanism comprises a first shell, a first biconvex lens, a second concave-convex lens, a doublet lens, a rear doublet lens and a third concave-convex lens, wherein the first biconvex lens is detachably connected to the first shell and is located in the first shell, the second concave-convex lens is detachably connected to the first shell and is located on one side of the first biconvex lens, the doublet lens is detachably connected to the first shell and is located on a side away from the first biconvex lens, the rear doublet lens is detachably connected to the first shell and is located on a side away from the second concave-convex lens, and the third concave-convex lens is detachably connected to the first shell and is located on a side away from the doublet lens; The eyepiece mechanism includes a second shell, a plano-convex lens, a fourth concave-convex lens, a front doublet lens and a rear doublet lens. The plano-convex lens is detachably connected to the second shell and is located on a side of the third concave-convex lens. The fourth concave-convex lens is detachably connected to the second shell and is located on a side away from the third concave-convex lens. The front doublet lens is detachably connected to the second shell and is located on a side away from the plano-convex lens. The rear doublet lens is detachably connected to the second shell and is located on a side away from the fourth concave-convex lens.

2. The lightweight low-light-level night vision device optical system according to claim 1, characterized in that: The objective lens mechanism has a length of 78.7 mm ± 0.5 mm, a focal length of 65 mm, a relative aperture of 1 / 1.38, a field of view of 10°, wavelengths of 560 mm, 720 mm and 867 mm, and a distortion of less than 2%.

3. The lightweight low-light-level night vision device optical system according to claim 1, characterized in that: The image intensifier has a diameter of 18 mm, a magnification of 1, and an optical length of 10 mm.

4. The lightweight low-light-level night vision device optical system as claimed in claim 1, characterized in that: The length of the eyepiece mechanism is 34 mm and the focal length is 14.5 mm.

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