Infrared prime lens for non-contact gun aiming instrument
By using a two-lens structure and a specially designed aspherical lens, the problem of high cost of infrared lenses has been solved, realizing a low-cost and high-imaging-quality infrared fixed-focus lens that meets the infrared thermal imaging requirements of non-contact gun sights.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2025-03-18
- Publication Date
- 2026-03-06
AI Technical Summary
Existing infrared lenses are expensive and fail to meet the performance requirements of infrared thermal imaging, especially in non-contact gun sights where the image clarity requirements are not effectively met.
It adopts a two-lens structure, with both the first and second lenses having positive optical power and being aspherical lenses. Combined with a specific aperture number and refractive index, it uses low refractive index materials and is designed with a single-sided concave and single-sided convex structure, with a diffraction surface to reduce costs.
It achieves a low-cost infrared fixed-focus lens with a large aperture and high imaging quality, suitable for the infrared thermal imaging needs of non-contact gun sights.
Smart Images
Figure CN223977423U_ABST
Abstract
Description
Technical Field
[0001] This utility model relates to the field of infrared lens technology, and in particular to an infrared fixed-focus lens for non-contact gun sights. Background Technology
[0002] Infrared thermography equipment and firearm sights, among other non-contact instruments, are widely used in outdoor search and rescue, hunting activities, and forest security monitoring due to their high imaging quality and low power consumption. Currently, most infrared lenses on the market employ a design with two or more large lenses, resulting in high costs. Therefore, developing a new type of lens that meets the performance requirements of infrared thermal imaging while also being cost-effective has become a crucial and urgent issue. Utility Model Content
[0003] This invention proposes an infrared fixed-focus lens for non-contact gun sights, which meets the requirements of infrared thermal imaging and effectively controls the lens cost.
[0004] The technical solution of this utility model is implemented as follows: an infrared fixed-focus lens for a non-contact gun sight includes a first lens, an aperture, a second lens, a window, and a detector arranged sequentially from the object side to the image side; both the first lens and the second lens are positive optical power, the object side and the image side of the first positive lens are convex and concave respectively, and the object side and the image side of the second positive lens are convex and concave respectively.
[0005] Furthermore, the first lens is an aspherical lens with a diffraction surface, and the second lens is an aspherical lens.
[0006] Furthermore, the aperture number Fno of the infrared fixed-focus lens is ≤1.0.
[0007] Furthermore, 1.6 < |f1 / f| < 1.8, 1.4 < |f2 / f| < 1.6, where 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.
[0008] Furthermore, both the first and second lenses are aspherical lenses and satisfy the following equation:
[0009]
[0010] Where X is the depth (mm) of the aspherical lens; Y is the distance (height) from the optical axis to the lens surface (mm); C is the radius of curvature of the lens, C=1 / R; K is the conic constant; and b, c, d, e, f, g, and h are the aspherical lens coefficients.
[0011] Furthermore, the first lens is an aspherical lens with a diffraction surface. The first lens with the diffraction surface has a gain effect.
[0012] Furthermore, Nd1(10.6)<3, Nd2(10.6)<3, where Nd1(10.6) is the refractive index of the first lens at a wavelength of 10.6μm; and Nd2(10.6) is the refractive index of the second lens at a wavelength of 10.6μm.
[0013] The beneficial effects of this utility model are:
[0014] This invention relates to an infrared fixed-focus lens, employing a two-lens structure. Both the first and second lenses are of positive optical power. The combined structural design of these two lenses results in an infrared fixed-focus lens with a large aperture and compact structure, achieving a lower cost compared to existing infrared fixed-focus lenses. It is suitable for non-contact infrared gun sights, where the primary purpose is thermal imaging detection, requiring high image clarity. This invention meets the needs of infrared thermal imaging while effectively controlling lens costs. Attached Figure Description
[0015] To more clearly illustrate the technical solutions in the embodiments of this utility model or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.
[0016] Figure 1 This is a schematic diagram of the structure of this utility model;
[0017] Figure 2 This is a schematic diagram of spherical aberration in an infrared fixed-focus lens.
[0018] Figure 3 This is a schematic diagram of astigmatism in an infrared fixed-focus lens at room temperature.
[0019] Figure 4 This is a schematic diagram of the distortion of an infrared fixed-focus lens at room temperature.
[0020] Figure 5 This is a schematic diagram of the infrared fixed-focus lens at room temperature.
[0021] First lens 1, aperture 2, second lens 3, window 4, detector 5. Detailed Implementation
[0022] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.
[0023] like Figure 1 As shown, an infrared fixed-focus lens for a non-contact gun sight includes a first lens 1 with positive optical power, an aperture 2, a second lens 3 with positive optical power, a window 4, and a detector 5, arranged sequentially from the object side to the image side. The aperture 2 is located between the first lens 1 and the second lens 3, which ensures a large light throughput and high-quality imaging effect.
[0024] The first positive lens has an object-side surface that is convex and an image-side surface that is concave, respectively. The second positive lens also has an object-side surface that is convex and an image-side surface that is concave, respectively. The lenses are designed with one concave side and one convex side for ease of manufacturing and assembly with the platform. The object-side surface is the side of the lens closest to the object, and the image-side surface is the side of the lens closest to the image.
[0025] The aperture number of the infrared fixed-focus lens is Fno≤1.0; the smaller the aperture number, the greater the overall light transmission, which can ensure that the detector 5 receives stronger light and the temperature measurement is more accurate.
[0026] 1.6 < |f1 / f| < 1.8, 1.4 < |f2 / f| < 1.6, where 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 a lens is determined by the structure of its front and rear surfaces and the material of the lens. The focal length reflects the overall situation after the front and rear surfaces of the lens are combined, and 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 achieve different field of view angles.
[0027] Nd1(10.6)<3, Nd2(10.6)<3, where Nd1(10.6) represents the refractive index of the first lens 1 at a wavelength of 10.6 μm; and Nd2(10.6) represents the refractive index of the second lens 3 at a wavelength of 10.6 μm. The lenses are made of a low-refractive-index material, resulting in slightly lower material costs and thus effectively controlling the cost of the lens.
[0028] Taking Fno = 1.0, the lens as sulfur material, and f = 35 as an example.
[0029] Table 1: Basic Lens Data
[0030] Face number radius of curvature R Surface spacing D Material First lens 1 object side 10.80 5.00 sulfur glass Image side view of first lens 1 10.59 10.37 Guanglan K-face Infinity 9.47 The object side of the second lens 3 21.00 5.00 sulfur glass The image side of the second lens 3 130.00 2.00 Germanium window (window 4) Infinity 1.00 Germanium / silicon glass Detector 5 Image Surface Infinity 11.60
[0031] In the table above, the radius of curvature R represents the radius of curvature value of the corresponding surface, in mm, and the surface spacing D represents the lens thickness or the spacing between lenses, in mm. The table also provides the lens material.
[0032] In this embodiment, both the first lens 1 and the second lens 3 are aspherical lenses. The coefficients of the aspherical lens are expressed with the center of the lens surface as the origin and the optical axis as the x-axis. The expression for the aspherical surface shape of the lens surface satisfies the following formula:
[0033]
[0034] Where X is the depth of the aspherical lens (mm); Y is the distance from the optical axis to the lens surface (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, h are the aspherical lens coefficients.
[0035] Table 2 Specific parameters of aspherical lens coefficients
[0036]
[0037] Table 3 Optical System Parameters
[0038] f FNO. 2ω TTL 35 1.0 16.1 46.5
[0039] In the table above, the lens focal length f is in mm, Fno. is the aperture size, ω in the angle of view 2ω represents the half angle of view, and the total optical length TTL is in mm.
[0040] The infrared fixed-focus lens of this embodiment was tested at room temperature. Figures 2-5 These are the spherical aberration diagram, astigmatism diagram, distortion diagram, and RI diagram at room temperature.
[0041] From Table 3 and Appendix Figure 2-4 As can be seen, the various aberrations of the infrared fixed-focus lens in this embodiment are well corrected, making it suitable for non-contact infrared gun aiming devices.
[0042] The above description is only a preferred embodiment of the present utility model and is not intended to limit the present utility model. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present utility model should be included within the protection scope of the present utility model.
Claims
1. An infrared fixed focus lens for a non-contact gunsight instrument, characterized by: The infrared fixed focus 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 and the second lens are both positive lenses, the object side and the image side of the first positive lens are a convex surface and a concave surface in sequence, and the object side and the image side of the second positive lens are a convex surface and a concave surface in sequence. The first lens and the second lens are sulfur glass. The focal length f of the infrared fixed focus lens is 35 mm. 1.6 < |f1 / f| < 1.8, 1.4 < |f2 / f| < 1.6, 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.
2. The infrared fixed focus lens for a non-contact gunsight device according to claim 1, characterized in that: The first lens and the second lens are both aspheric lenses.
3. An infrared fixed focus lens for a non-contact gunsight device according to claim 2, characterized in that: The first lens is an aspheric lens with a diffraction surface.
4. An infrared fixed focus lens for a non-contact gunsight device according to any one of claims 1 to 3, characterized in that: The aperture number Fno of the infrared fixed focus lens is less than or equal to 1.
0.
5. An infrared fixed focus lens for a non-contact gunsight device according to any one of claims 1-3, characterized in that: 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.