A gun sight infrared lens, lens module

Abstract

The application belongs to the field of infrared optical technology and discloses a gun sighting infrared lens and a lens module. The lens comprises a first lens and a second lens arranged in sequence from an object side to an image side. The first lens and the second lens are both meniscus lenses with convex surfaces facing the object side. The optical powers of the first lens and the second lens are both positive. The air gap between the first lens and the second lens is 19.01 mm. The application makes the lens structure compact by reasonably distributing the optical power, corrects various aberrations by reasonably arranging the lenses, improves the edge image quality, and thus improves the imaging quality. The F number is 1, so that the lens can clearly image under weak light and has stable working performance. The application only adopts one piece of germanium lens and one piece of lens made of chalcogenide glass, so that the imaging quality is ensured and the cost is low.

Description

Technical Field

[0001] This technology belongs to the field of infrared optical technology, and specifically relates to a gun sight infrared lens and lens module. Background Technology

[0002] Infrared imaging technology currently has wide applications in both military and civilian fields. Infrared thermal imaging gun sights primarily rely on the temperature difference of the target surface to detect thermal targets. They can achieve all-weather observation, have strong anti-interference capabilities, long operating range, and are suitable for low-light environments and adverse weather conditions. They have a strong ability to detect and identify targets and are widely used in security reconnaissance, military confrontation, and other fields.

[0003] Existing rifle scope lenses typically employ multiple lenses to achieve higher image quality, and these lenses often use high-cost germanium materials. Therefore, they cannot meet the needs of a compact, high-quality, and economical infrared system. Summary of the Invention

[0004] To address the above problems, one objective of this invention is to provide a gun sight infrared lens. The specific technical solution is as follows:

[0005] An infrared scope for rifle aiming, the lens comprising a first lens and a second lens arranged sequentially from the object side to the image side; both the first lens and the second lens are meniscus lenses with their convex surfaces facing the object side; both the first lens and the second lens have positive optical power; the air gap between the first lens and the second lens is 19.01 mm.

[0006] Furthermore, the first lens has a center thickness of 2.3 mm, an object-side radius of curvature of 20.43 mm, and an image-side radius of curvature of 22.87 mm; the second lens has a center thickness of 2.2 mm, an object-side radius of curvature of 15.80 mm, and an image-side radius of curvature of 18.98 mm.

[0007] Furthermore, the first lens and the second lens are made of germanium and chalcogenide glass, respectively.

[0008] Furthermore, the object-side surface of the first lens, the image-side surface of the first lens, and the object-side surface of the second lens are aspherical surfaces, and satisfy the aspherical surface formula:

[0009]

[0010] Where Z is the distance vector from the vertex of the aspherical surface at a height r along the optical axis; c = 1 / R; R is the paraxial curvature fitting radius of the mirror; k is the conic coefficient; A, B, C, D, and E are higher-order aspherical coefficients.

[0011] Furthermore, the image-side surface of the second lens is a binary surface, satisfying the aspherical formula and the equation for the binary surface in Zemax: M(B1ρ) 2 +B2ρ 4 ); where M is the diffraction order, B1 and B2 are the binary phase coefficients, and ρ is the normalized radius.

[0012] Furthermore, M=1, B1=-13.18, B2=0.88, ρ=6.40.

[0013] Furthermore, an aperture is provided on the image side of the first lens.

[0014] Furthermore, the lens operates in the wavelength range of 8μm to 12μm and has an F-number of 1.

[0015] Another object of the present invention is to provide a lens module, including the above-mentioned gun sight infrared lens and a photosensitive element, wherein the photosensitive element is used to convert the optical image formed by the gun sight infrared lens into an electrical signal.

[0016] Furthermore, the photosensitive element is a detector, the detector has 384×288 pixels and a pixel size of 12μm.

[0017] Compared with the prior art, one or more of the above technical solutions can achieve at least one of the following beneficial effects:

[0018] This invention achieves a compact lens structure through reasonable allocation of optical power and corrects various aberrations by rationally arranging the lenses, thereby improving edge image quality and thus enhancing overall image quality. With an F-number of 1, the lens can achieve clear imaging even in low light and maintains stable performance. This lens uses only one germanium lens and one chalcogenide glass lens, ensuring image quality while maintaining low cost. Attached Figure Description

[0019] To more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0020] Figure 1 This is the optical path diagram of the infrared lens for the gun sight in Example 1.

[0021] Figure 2 This is a diagram showing the lens composition of the infrared lens for a rifle sight in Example 1.

[0022] Figure 3 This is a dot diagram of the infrared lens used for gun aiming in Example 1.

[0023] Figure 4 This is the MTF diagram of the infrared lens of the gun sight in Example 1.

[0024] Reference numerals: 1. First lens; 2. Second lens; 3. Protective window; 4. Image plane. Detailed Implementation

[0025] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention. It should be noted that the terms "first" and "second" are used only for descriptive purposes and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features.

[0026] To facilitate understanding, the relevant terms are explained below.

[0027] The object side is the side where the object is located, with the lens as the boundary; the object side surface is the surface of the lens closest to the object side; the image side is the side where the image of the object is located, with the lens as the boundary; the image side surface is the surface of the lens closest to the image side; a meniscus lens, also known as a crescent-shaped lens, has one concave surface and the other convex surface.

[0028] Example 1

[0029] like Figure 1 As shown, this embodiment provides a gun sight infrared lens. The lens includes a first lens 1 and a second lens 2 arranged sequentially from the object side to the image side; the first lens 1 is a meniscus lens with its convex surface facing the object side, and the second lens 2 is a meniscus lens with its convex surface facing the object side; the optical power of both the first lens 1 and the second lens 2 is positive.

[0030] As shown in Table 1, Figure 2 As shown, the center thickness of the first lens 1 is 2.3 mm, the radius of curvature of the object-side surface S1 is 20.43 mm, and the radius of curvature of the image-side surface S2 is 22.87 mm; the center thickness of the second lens 2 is 2.2 mm, the radius of curvature of the object-side surface S3 is 15.80 mm, and the radius of curvature of the image-side surface S4 is 18.98 mm. The air gap between the first lens 1 and the second lens 2 is 19.01 mm. The object-side surface S1 of the first lens 1 is a convex surface of a meniscus lens, and the image-side surface S2 is a concave surface of a meniscus lens.

[0031] In one specific implementation, an aperture is provided on the image-side surface S2 of the first lens 1.

[0032] The first lens 1 and the second lens 2 are made of germanium and chalcogenide glass, respectively. Compared with the prior art where all lenses are made of germanium, this embodiment significantly reduces costs.

[0033] Table 1 Parameters of each component

[0034]

[0035] As a specific implementation, as shown in Table 2, the object-side surface S1 of the first lens 1, the image-side surface S2 of the first lens, and the object-side surface S3 of the second lens 2 are aspherical surfaces and satisfy the aspherical surface formula:

[0036]

[0037] Where Z is the distance vector from the vertex of the aspherical surface at a height r along the optical axis; c = 1 / R; R is the paraxial curvature fitting radius of the mirror; k is the conic coefficient; A, B, C, D, and E are higher-order aspherical coefficients.

[0038] Table 2 Aspherical data of lenses

[0039]

[0040] The image-side surface S4 of the second lens 2 is a binary surface, satisfying the above aspherical formula while also satisfying the expression equation for a binary surface in Zemax: M(B1ρ 2 +B2ρ 4 ); where M is the diffraction order, the diffraction order is 1, B1 and B2 are the phase coefficients of the binary surface, B1 = -13.18, B2 = 0.88, and the normalized radius ρ is 6.40.

[0041] Figure 3 , Figure 4 These are the dot plot and MTF plot of the lens, respectively. In the MTF plot, the horizontal axis represents different spatial frequencies, and the vertical axis represents modulation. All fields of view represent the MTF curves of the meridional plane. It can be seen that the MTF is close to the diffraction limit, the root mean square diameter of the spot of confusion is smaller than the diameter of the Airy disk, and the image quality is good.

[0042] The infrared lens of the rifle sight in this embodiment achieves the following optical parameters:

[0043] Operating wavelength: 8μm~12μm;

[0044] F-number: 1;

[0045] Resolution: 384×288, 12μm;

[0046] Focal length: 25mm.

[0047] The lens in this embodiment achieves high image quality while maintaining a compact structure and low cost through the reasonable allocation of optical power and the design of optical materials, aspherical surfaces, and diffraction surfaces. It is an economical lens that is particularly suitable for fields such as security reconnaissance and military confrontation.

[0048] This embodiment also provides a lens module, including the aforementioned rifle sight infrared lens and a photosensitive element. The photosensitive element is used to convert the optical image formed by the rifle sight infrared lens into an electrical signal. In this embodiment, the photosensitive element is a detector with a pixel count of 384×288 and a pixel size of 12μm.

[0049] Obviously, the above embodiments are merely examples to clearly illustrate the technical solutions of the present invention, and are not intended to limit the implementation of the present invention. Those skilled in the art can make other variations or modifications based on the above description. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the protection scope of the claims of the present invention.

Claims

1. A rifle sight infrared lens, characterized in that, The lens includes a first lens and a second lens arranged sequentially from the object side to the image side; both the first and second lenses are meniscus lenses with their convex surfaces facing the object side; both the first and second lenses have positive optical power; the air gap between the first and second lenses is 19.01 mm; the center thickness of the first lens is 2.3 mm, the object-side radius of curvature is 20.43 mm, and the image-side radius of curvature is 22.87 mm; the center thickness of the second lens is 2.2 mm, the object-side radius of curvature is 15.80 mm, and the image-side radius of curvature is 18.98 mm; the first and second lenses are made of germanium and chalcogenide glass, respectively; the object-side surface of the first lens, the image-side surface of the first lens, and the object-side surface of the second lens are aspherical; the image-side surface of the second lens is a binary surface; the lens has two lenses with optical power.

2. The infrared lens for gun aiming according to claim 1, characterized in that, The aspherical surface satisfies the aspherical surface formula: Where Z is the distance vector from the vertex of the aspherical surface at a height r along the optical axis; c = 1 / R; R is the paraxial curvature fitting radius of the mirror; k is the conic coefficient; A, B, C, D, and E are higher-order aspherical coefficients.

3. The infrared lens for gun aiming according to claim 2, characterized in that, The binary surface satisfies the aspherical formula and the equation for the binary surface in Zemax: M(B1ρ) 2 +B2ρ 4 ); where M is the diffraction order, B1 and B2 are the binary phase coefficients, and ρ is the normalized radius.

4. The infrared gun sight lens according to claim 3, characterized in that, M=1, B1=-13.18, B2=0.88, ρ=6.

40.

5. The infrared lens for gun aiming according to claim 1, characterized in that, An aperture is provided on the image side of the first lens.

6. The gun-aiming infrared lens according to any one of claims 1 to 5, characterized in that, The lens operates in the wavelength range of 8μm to 12μm and has an F-number of 1.

7. A lens module, characterized in that, The invention includes a rifle sight infrared lens as described in any one of claims 1 to 6 and a photosensitive element, wherein the photosensitive element is used to convert the optical image formed by the rifle sight infrared lens into an electrical signal.

8. The lens module according to claim 7, characterized in that, The photosensitive element is a detector, and the detector has 384×288 pixels and a pixel size of 12μm.

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