Small-angle infrared detection lens

Abstract

The utility model discloses a small-angle infrared detection lens, which relates to the technical field of imaging, and is characterized in that the small-angle infrared detection lens sequentially comprises a first lens, a second lens and a diaphragm from an object plane to an image plane, the diaphragm is positioned between the first lens and the second lens, the first lens has a positive focal length, the second lens has a negative focal length, and the diaphragm is positioned between the first lens and the second lens. The first lens is a convex lens of a spherical structure, and the second lens is a concave lens of an even aspheric structure. According to the utility model, the optical distortion is controlled within-3.5%, the TV distortion is less than 1%, and the imaging quality is excellent. Glass or plastic materials are utilized, the glass lens is of a high refractive index and aspherical design, aberration such as spherical aberration, coma and astigmatism is effectively corrected, the resolution reaches 300 thousand pixels or above, and the requirement for high resolution is met. And the diaphragm adjustment is flexible. The structure is stable and easy to assemble.

Description

Technical Field

[0001] This utility model relates to the field of imaging technology, specifically a small-angle infrared detection lens. Background Technology

[0002] With the rapid development of infrared detection technology, its applications are becoming increasingly widespread, especially in fields such as smart cars, smart homes, industrial inspection, and consumer electronics. As a core component of infrared detection systems, the performance of infrared lenses directly affects detection accuracy and imaging quality. However, existing infrared lenses still have some shortcomings in design and performance, making it difficult to fully meet the growing market demand.

[0003] Existing infrared lenses often struggle to effectively control distortion in their optical design, especially in wide-angle or narrow-angle detection scenarios, where optical and TV distortions are significant, impacting image quality. Distortion issues cause shape distortion of detected objects, reducing detection accuracy, particularly in high-precision applications such as automotive driver assistance and industrial inspection. The resolution of existing infrared lenses is generally low, failing to meet high-resolution imaging requirements. This is especially true in consumer electronics such as smart locks and smart screens, where user demand for high-definition imaging is increasing. Low resolution limits the application of infrared lenses in detail and long-distance detection. Furthermore, the aperture design of existing infrared lenses is relatively simple, lacking a flexible light flux adjustment mechanism, making it difficult to adapt to detection needs under different lighting conditions. This inconvenience in light flux adjustment leads to poor imaging performance in strong or low-light environments. Utility Model Content

[0004] The purpose of this invention is to provide a small-angle infrared detection lens to solve the problems existing in the background technology.

[0005] To achieve the above objectives, this utility model provides the following technical solution:

[0006] A small-angle infrared detection lens, characterized in that: from the object plane to the image plane, it includes a first lens, a second lens and an aperture stop, the aperture stop being located between the first lens and the second lens, the first lens having a positive focal length, the second lens having a negative focal length, the first lens being a convex lens with a spherical structure, and the second lens being a concave lens with an even-order aspherical structure.

[0007] In a preferred embodiment, the first lens is made of glass, the radius of curvature of the R1 surface of the first lens is 4.19 to 4.34 mm, the radius of curvature of the R2 surface is -17.12 to -18.01 mm, the thickness is 2.56 to 2.41 mm, the refractive index of the material is 1.764 to 1.993, and the dispersion coefficient is 21.946 to 25.996.

[0008] In a preferred embodiment, the second lens is made of plastic, with an RI surface radius of curvature of -2.45 to -2.75 mm, an R2 surface radius of curvature of -6.11 to -6.23 mm, a thickness of 2.15 to 2.31 mm, a refractive index of 1.524 to 1.593, and a dispersion coefficient of 55.946 to 55.996. It is also an even-order aspherical lens.

[0009] A preferred technical solution further includes a fixed housing, which includes a first lens sleeve, a second lens sleeve, and an outer sleeve. The first lens is fixedly disposed inside the first lens sleeve, and the second lens is fixedly disposed inside the second lens sleeve. One of the first lens sleeve and the second lens sleeve is fixedly disposed at one end of the outer sleeve, and the other is disposed at the other end of the outer sleeve by a threaded connection.

[0010] In a preferred embodiment, the aperture is set inside the outer sleeve via an adjustment mechanism. The adjustment mechanism includes a fixed plate fixedly set inside the outer sleeve, the aperture being rotatably set on the fixed plate, the aperture having light-transmitting holes of different sizes, and an adjustment tooth being set on the outer side of the aperture. An adjustment gear is rotatably set on the outer sleeve, the adjustment gear meshing with the adjustment tooth, and one side of the adjustment gear passing through the outer sleeve and extending to the outer side of the outer sleeve.

[0011] Compared with the prior art, the beneficial effects of this utility model are as follows:

[0012] Low distortion design:

[0013] By using the even-order aspherical design of the first lens 1 and the second lens 2, optical distortion is controlled within -3.5%, TV distortion is less than 1%, and the imaging quality is excellent.

[0014] High resolution:

[0015] Utilizing the low dispersion coefficient of glass or plastic materials and the aspherical design, it effectively corrects aberrations such as spherical aberration, coma, and astigmatism, achieving a resolution of over 300,000 pixels to meet high-resolution requirements.

[0016] The aperture is adjustable.

[0017] The aperture 3 is designed with multiple light-transmitting holes 31. The light flux can be manually adjusted by adjusting the gear 53 to adapt to different lighting conditions, and the operation is simple.

[0018] Sturdy structure and easy assembly:

[0019] The fixed housing 4 adopts a threaded connection design, which facilitates assembly and adjustment, while ensuring the stability and durability of the lens structure.

[0020] Wide range of application scenarios:

[0021] Suitable for high-precision, high-temperature environments (such as automotive infrared detection and industrial inspection). Also suitable for low-cost, lightweight applications (such as smart locks, consumer electronics, and drones). Attached Figure Description

[0022] To more clearly illustrate the technical solutions of the embodiments of this utility model, the accompanying drawings used in the description of the embodiments 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.

[0023] Figure 1 This is a cross-sectional structural diagram of the present invention.

[0024] Figure 2 This is a three-dimensional structural diagram of the present invention.

[0025] Figure 3 This is a schematic diagram of the aperture and adjustment mechanism of this utility model.

[0026] Figure 4 This is a schematic diagram of the Mtf diagram of Embodiment 1 of this utility model.

[0027] Figure 5 This is a focus curve diagram of an embodiment of the present invention.

[0028] Figure 6 A series of diagrams are shown for an embodiment of this utility model.

[0029] Figure 7 This is a relative illumination diagram of one embodiment of the present utility model.

[0030] Figure reference numerals: 1-First lens, 2-Second lens, 3-Aperture, 4-Fixed housing, 5-Adjustment mechanism, 31-Light transmission hole, 41-First lens sleeve, 42-Second lens sleeve, 43-Outer sleeve, 51-Fixed piece, 52-Adjusting tooth, 53-Adjusting gear. Detailed Implementation

[0031] The following embodiments will be described in detail with reference to the accompanying drawings. In the drawings and description, similar or identical parts are referred to by the same reference numerals. Furthermore, in practical applications, the shape, thickness, or height of each component may be enlarged or reduced. The embodiments listed in this utility model are merely illustrative and not intended to limit the scope of the utility model. Any obvious modifications or alterations made to this utility model do not depart from its spirit and scope.

[0032] like Figures 1-7 As shown,

[0033] Example 1

[0034] 1. Lens Structure

[0035] Optical structure from object plane to image plane:

[0036] First lens 1: Positive focal length, spherical convex lens, made of glass.

[0037] Aperture 3: Located between the first lens 1 and the second lens 2, used to control the light flux.

[0038] Second lens 2: a concave lens with negative focal length and an even-order aspherical structure, made of plastic.

[0039] 2. Lens parameters

[0040] First lens 1:

[0041] RI radius of curvature: 4.19~4.34mm; R2 radius of curvature: -17.12~-18.01

[0042] Thickness: 2.56~2.41mm

[0043] Material refractive index: 1.764~1.993

[0044] Dispersion coefficient: 21.946~25.996

[0045] Second lens 2:

[0046] RI radius of curvature: -2.45 to -2.75; RI radius of curvature: -6.11 to -6.23

[0047] Thickness: 2.15~2.31mm

[0048] Material refractive index: 1.524~1.593

[0049] Dispersion coefficient: 55.946~55.996

[0050] The even-order aspherical coefficients of the second lens are as follows:

[0051]

[0052] 3. Mechanical structure

[0053] Fixed outer casing 4:

[0054] First lens sleeve 41: used to fix the first lens 1.

[0055] Second lens sleeve 42: used to fix the second lens 2.

[0056] Outer sleeve 43: The first lens sleeve 41 and the second lens sleeve 42 are respectively fixed at their two ends, one of which is connected by a thread for easy adjustment and assembly.

[0057] Aperture 3 and adjustment mechanism 5:

[0058] Aperture 3: Located inside the outer sleeve 43, it has multiple light-transmitting holes 31 of different sizes for adjusting the light flux.

[0059] Adjustment mechanism 5:

[0060] Fixing plate 51: Fixed inside the outer sleeve 43, used to support the aperture 3.

[0061] Adjustment gear 52: Located outside the aperture 3, it meshes with the adjustment gear 53.

[0062] Adjustment gear 53: Rotatably mounted on the outer sleeve 43. By rotating the adjustment gear 53, the aperture 3 is rotated to select different sizes of light-transmitting holes 31.

[0063] 4. Optical performance

[0064] Low distortion: Through the even-order aspherical design of the first lens 1 and the second lens 2, optical distortion is controlled within -5%, and TV distortion is less than 1%.

[0065] High resolution: By utilizing the high refractive index and low dispersion coefficient of the glass material, aberrations such as spherical aberration, coma, and astigmatism are corrected, achieving a resolution of over 8 million pixels.

[0066] Temperature stability: The glass material has good thermal stability and can work without defocusing in environments ranging from -40℃ to +60℃.

[0067] Example 2

[0068] The first lens 1 is made of plastic, with a radius of curvature of -2.58 to -2.73 mm, a thickness of 2.25 to 2.40 mm, a refractive index of 1.524 to 1.593, and a dispersion coefficient of 55.946 to 55.996. The second lens 2 is also made of plastic, with a radius of curvature of -6.09 to -6.24 mm and a thickness of 0.02 to 0.17 mm. Other structural features are consistent with those of Embodiment 1.

[0069] Optical performance

[0070] Low distortion: Through the design of even-order aspherical surfaces made of plastic, optical distortion is controlled within -5%, and TV distortion is less than 1%.

[0071] High resolution: Through the low dispersion coefficient of plastic material and even-order aspherical design, aberrations are corrected, and the resolution reaches more than 8 million pixels.

[0072] Low cost: Plastic materials are cheaper than glass materials, making them suitable for mass production.

[0073] Lightweight: The plastic material is lightweight, making it suitable for weight-sensitive applications (such as drones and portable devices).

[0074] In this utility model

[0075] Aperture adjustment mechanism: The light-transmitting hole 31 of the aperture 3 is designed with multiple holes of different diameters. By rotating the adjustment gear 53, the appropriate light flux can be selected to adapt to different lighting conditions. The adjustment gear 53 extends to the outside of the outer sleeve 43 for easy manual adjustment by the user.

[0076] Advantages of aspherical design: The first lens 1 and the second lens 2 adopt an even-order aspherical design, which effectively corrects aberrations such as spherical aberration, coma, and astigmatism, thereby improving image quality. The aspherical design can also simplify the lens structure, reduce the number of lenses, and lower costs.

[0077] Temperature compensation design: Example 1 uses glass, which has good thermal stability and requires no additional temperature compensation. Example 2 uses plastic, and temperature compensation can be achieved through structural design (such as reserving thermal expansion gaps) or material selection (such as plastics with low thermal expansion coefficients).

[0078] Application scenarios:

[0079] Example 1: Suitable for high-precision, high-temperature environments, such as automotive infrared detection and industrial inspection.

[0080] Example 2: Applicable to low-cost, lightweight scenarios, such as smart door locks, consumer electronics, drones, etc.

[0081] Furthermore, it should be understood that although this specification describes embodiments, not every embodiment contains only one independent technical solution. This narrative style is merely for clarity. Those skilled in the art should consider the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.

Claims

1. A small angle infrared detection lens characterized in that: From object plane to image plane successively include first lens (1), second lens (2) and diaphragm (3), the diaphragm (3) is located between first lens (1) and second lens (2), the first lens (1) is positive focal length, the second lens (2) is negative focal length, the first lens is the convex lens of spherical spherical structure, and the second lens is the concave lens of even aspheric structure.

2. The small-angle infrared detection lens according to claim 1, characterized in that, The first lens (1) is glass material, the curvature radius of R1 surface of first lens is 4.19-4.34 mm, the curvature radius of R2 surface is-17.12- -18.01, the thickness is 2.56-2.41 mm, the material refractive index is 1.764-1.993, and the dispersion coefficient is 21.946-25.

996.

3. The small-angle infrared detection lens according to claim 2, characterized in that, The second lens (2) is plastic material, the curvature radius of RI surface of second lens (2) is-2.45- -2.75 mm, the curvature radius of R2 surface is-6.11- -6.23 mm, the thickness is 2.15-2.31 mm, the material refractive index is 1.524-1.593, and the dispersion coefficient is 55.946-55.

996. And it is even aspheric lens.

4. The small-angle infrared detection lens according to claim 1, wherein, It also includes a fixed shell (4), the fixed shell (4) includes a first lens sleeve (41), a second lens sleeve (42) and an external sleeve (43), the first lens (1) is fixedly arranged in the first lens sleeve (41), the second lens (2) is fixedly arranged in the second lens sleeve (42), one of the first lens sleeve (41), the second lens sleeve (42) is fixedly arranged at one end of the external sleeve (43), and the other is arranged at the other end of the external sleeve (43) through threaded connection.

5. The small-angle infrared detection lens according to claim 4, characterized in that, The diaphragm (3) is arranged on the inside of the external sleeve (43) through an adjusting mechanism (5), the adjusting mechanism (5) includes a fixed sheet (51) fixedly arranged on the inside of the external sleeve (43), the diaphragm (3) is rotatably arranged on the fixed sheet (51), the diaphragm (3) is provided with light transmission holes (31) of different sizes, the outside of the diaphragm (3) is provided with adjusting teeth (52), the external sleeve (43) is rotatably provided with an adjusting gear (53), the adjusting gear (53) is engaged with the adjusting teeth (52), and one side of the adjusting gear (53) extends to the outside of the external sleeve (43) through the external sleeve (43).

Images