Infrared prime lens for unmanned aerial vehicle

Abstract

The utility model provides an infrared prime lens for an unmanned aerial vehicle. The infrared prime lens comprises a first lens, a diaphragm, a second lens, a window and a detector which are sequentially arranged from an object side to an image side, the first lens has negative focal power, the second lens has positive focal power, the object side surface and the image side surface of the first lens are a convex surface and a concave surface in sequence, and the object side surface and the image side surface of the second positive lens are convex surfaces. The infrared prime lens provided by the utility model meets the requirement of infrared thermal imaging, effectively controls the cost and weight of the lens, and is suitable for being carried by an unmanned aerial vehicle.

Description

TECHNICAL FIELD

[0001] The utility model relates to infrared lens technical field, especially a kind of infrared fixed focus lens for unmanned aerial vehicle. BACKGROUND

[0002] Infrared lens is increasingly widely used in the field of unmanned aerial vehicle, and gives unmanned aerial vehicle powerful environmental perception and target recognition capability.Unmanned aerial vehicle carrying infrared lens can clearly image in completely no light, smoke or dust and other complex environments, greatly expands the operation time and application scenarios of unmanned aerial vehicle.Therefore, infrared lens unmanned aerial vehicle plays an important role in night patrol, search and rescue action, agricultural monitoring, power line patrol and other fields.However, as the core component of these devices, the manufacturing cost of infrared lens is high, which is mainly limited by the use of special materials and complex processing technology.Currently, the infrared lens on the market generally adopts two or more lens design scheme, which further increases the overall cost.Therefore, developing a new lens design scheme that can meet the requirements of infrared thermal imaging performance and has cost-effectiveness has become an important issue to be solved. SUMMARY

[0003] The utility model provides a kind of infrared fixed focus lens for unmanned aerial vehicle, meets infrared thermal imaging requirement, and effectively controls lens cost and weight, and is suitable for unmanned aerial vehicle carrying application.

[0004] The technical scheme of the utility model is realized as follows: a kind of infrared fixed focus lens for unmanned aerial vehicle, including first lens, diaphragm, second lens, window and detector arranged in order from object side to image side;First lens is negative optical power, and second lens is positive optical power, and the object side surface and image side surface of first lens are convex and concave in turn, and the object side surface and image side surface of second positive lens are both convex.

[0005] Further, the aperture number Fno of the infrared fixed focus lens is less than or equal to 1.0.

[0006] Further, |f1 / f|>35, 0.7<|f2 / f|<1, wherein f1 is the focal length of the first lens, f2 is the focal length of the second lens, and f is the focal length of the lens.

[0007] Further, the first lens and the second lens are both aspherical lenses, and satisfy the following equation:

[0008]

[0009] Wherein, Y is the distance (height) from the optical axis to the lens surface (mm), C is the curvature radius of the lens, C=1 / R, K is the conic constant, b, c, d, e, f, g, h are the coefficients of aspherical lens.

[0010] Further, the second lens is an aspheric lens with a diffraction surface.

[0011] Further, Nd1(10.6)<3, Nd2(10.6)<3, wherein, Nd1(10.6) is the refractive index of the first lens at the wavelength of 10.6 μm; and Nd2(10.6) is the refractive index of the second lens at the wavelength of 10.6 μm.

[0012] The present application has the following beneficial effects:

[0013] The infrared fixed-focus lens of the present application has a large aperture and a compact structure, and has a lower cost than the prior art.

[0014] The infrared fixed-focus lens of the present application is suitable for unmanned aerial vehicle applications, and can meet the requirements of infrared imaging and effectively control the weight and cost of the lens. BRIEF DESCRIPTION OF DRAWINGS

[0015] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the following will briefly introduce the drawings needed to be used in the embodiments or prior art description. Obviously, the drawings described below are only some embodiments of the present application, and for those skilled in the art, other drawings can also be obtained from these drawings without creative labor.

[0016] Figure 1 is a structural schematic diagram of the present application;

[0017] Figure 2 is a spherical aberration schematic diagram of the infrared fixed-focus lens;

[0018] Figure 3 is a coma schematic diagram of the infrared fixed-focus lens at room temperature;

[0019] Figure 4 is a distortion schematic diagram of the infrared fixed-focus lens at room temperature;

[0020] Figure 5 is a RI schematic diagram of the infrared fixed-focus lens at room temperature.

[0021] The first lens 1, the diaphragm 2, the second lens 3, the window 4, and the detector 5. DETAILED DESCRIPTION

[0022] The technical solutions in the embodiments of the utility model will be clearly and completely described below with reference to the drawings in the embodiments of the utility model. Obviously, the described embodiments are only part of the embodiments of the utility model, rather than all the embodiments. Based on the embodiments of the utility model, all other embodiments obtained by those skilled in the art without creative labor fall within the protection scope of the utility model.

[0023] As shown in the drawings, Figure 1 An infrared fixed-focus lens for a UAV, comprising a first lens 1, a diaphragm 2, a second lens 3, a window 4 and a detector 5 arranged in sequence from an object side to an image side, the diaphragm 2 being located between the first positive lens and the second positive lens; the infrared fixed-focus lens can guarantee a large light flux and a high-quality imaging effect. The first lens 1 has a negative focal power, the second lens 3 has a positive focal power, and the object side and the image side of the first lens 1 are a convex surface and a concave surface in sequence, and the object side and the image side of the second positive lens are both convex surfaces. The object side refers to one side of the lens close to the object side, and the image side refers to one side of the lens close to the image side.

[0024] The aperture number Fno of the infrared fixed-focus lens is less than or equal to 1.0, the smaller the aperture number of the lens, the larger the overall light flux, and the stronger the light intensity received by the detector 5, and the more accurate the temperature measurement.

[0025] |f1 / f|>3.5, 0.7<|f2 / f|<1, wherein f1 is the focal length of the first lens 1, f2 is the focal length of the second lens 3, and f is the focal length of the lens. The focal length of the lens is determined by the structure of the front and rear surfaces of the lens and the material of the lens. The focal length of the lens reflects the overall situation of the combination of the front and rear surfaces of the lens, which is a structural parameter of the lens. In a single-lens system, the smaller the focal length, the larger the field of view; the larger the focal length, the smaller the field of view; different focal lengths can realize different field angles.

[0026] Nd1(10.6)<3, Nd2(10.6)<3, wherein Nd1(10.6) is the refractive index of the first lens 1 at a wavelength of 10.6 μm, and Nd2(10.6) is the refractive index of the second lens 3 at a wavelength of 10.6 μm. The lens is made of a material with low refractive index, which slightly reduces the cost of the material, thereby effectively controlling the cost of the lens.

[0027] For example, Fno=1.0, the lens is made of sulfur material, and f=7.

[0028] The basic lens data is shown in Table 1.

[0029] Table 1: Basic lens data

[0030]

[0031]

[0032] In the above table, the radius of curvature R represents the radius of curvature value of the corresponding surface, in mm, the surface interval D represents the lens thickness or the interval value between lenses, in mm, and the lens material is given in the above table.

[0033] The first lens 1 and the second lens 3 are both aspherical lenses, the coefficients of the aspherical lenses are taken as the origin of the lens surface center, the optical axis as the x-axis, and the aspherical surface expression of the lens surface satisfies the following formula:

[0034]

[0035] wherein X is the depth of the aspherical lens, in mm; Y is the distance (height) from the optical axis to the lens surface, in mm; C is the radius of curvature of the aspherical lens, C = 1 / R; K is the conic constant; and b, c, d, e, f, g, and h are the coefficients of the aspherical lens.

[0036] Table 2: Specific parameters of aspherical lens coefficients

[0037]

[0038] Table 3: Optical system parameters

[0039] f FNO. 2ω TTL 7 1.0 31.6 12.4

[0040] In Table 3, the unit of the near-axis focal length f is mm, Fno. is the aperture size, ω in the view angle 2ω represents the half view angle, and the unit of the total optical length TTL is mm.

[0041] The infrared fixed-focus lens of the present embodiment was tested at room temperature, Figures 2-5 The ball aberration diagram, the astigmatism diagram, the distortion diagram, and the RI diagram at room temperature are shown in FIGS. 6-9, respectively. Figures 2-4 It can be seen that the various aberrations of the infrared fixed-focus lens of the present embodiment are well corrected, and the infrared fixed-focus lens can be applied to unmanned aerial vehicle applications.

[0042] The above merely provides the preferred embodiments of the present application and is not intended to limit the present application, and any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. An infrared prime lens for a drone, characterized by: The infrared focusing lens comprises, in sequence from the object side to the image side, a first lens, a diaphragm, a second lens, a window and a detector; the first lens has negative focal power, and the second lens has positive focal power; the object side surface and the image side surface of the first lens are a convex surface and a concave surface in sequence, and the object side surface and the image side surface of the second lens are both convex surfaces; The curvature radius R of the object side surface of the first lens is 6.52, and the curvature radius R of the image side surface of the first lens is 5.30; The curvature radius R of the object side surface of the second lens is 30.14, and the curvature radius R of the image side surface of the second lens is -14.69; The second lens is a non-spherical lens with a diffraction surface. 2.The infrared fixed-focus lens for a UAV according to claim 1, wherein: The aperture number Fno of the infrared focusing lens is less than or equal to 1.

0. 3.The infrared fixed-focus lens for a UAV according to claim 1, wherein: |f1 / f|>35, 0.7<|f2 / f|<1, wherein f1 is the focal length of the first lens, f2 is the focal length of the second lens, and f is the focal length of the lens.

4. The infrared fixed focus lens for a UAV according to claim 1, wherein: The first lens and the second lens are both non-spherical lenses.

5. The infrared prime lens for a UAV according to claim 1, wherein: Nd1(10.6)<3, Nd2(10.6)<3, wherein Nd1(10.6) is the refractive index of the first lens at a wavelength of 10.6 μm, and Nd2(10.6) is the refractive index of the second lens at a wavelength of 10.6 μm. ​

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