A high-quality wide-angle, low-distortion lens

Abstract

This invention relates to the field of imaging optics technology, specifically to a high-quality wide-angle, low-distortion lens. It achieves the same imaging quality as using cemented lenses without requiring them, resulting in a total optical length (TTL) of 12.2mm, resistance to temperatures above 85 degrees Celsius, a pixel count of over 300W, an ultra-wide-angle diagonal of 146 degrees, low distortion (TV distortion only 16%), a large aperture of F / NO=2.15, day / night confocal focusing capability, and high cost-effectiveness (only 1G3P). The first lens is a glass lens, while the remaining lenses are plastic lenses. Traditionally, achieving the same effect requires 5G.

Description

Technical Field

[0001] This invention relates to the field of imaging optics, and more specifically, to a high-quality wide-angle, low-distortion lens. Background Technology

[0002] With the development of lens and electronic technology, lenses are no longer limited to camera systems. Besides traditional DV shooting, lenses are now used in various other video capture environments, such as surveillance systems capturing the surrounding environment, and various vehicle devices including buses, trucks, and motorcycles. Existing traditional lenses, such as the wide-angle low-distortion lens with patent publication number CN115113376A, often use cemented lenses to ensure image quality. Cemented lenses bond multiple optical elements during manufacturing to reduce lens size and improve optical performance. However, this structure suffers from optical performance degradation, internal contamination, and difficulty in cleaning and repair under temperature changes, humidity fluctuations, and prolonged use. Therefore, a new lens design is urgently needed that can achieve the image quality of cemented lenses without cementing the lens elements, thus overcoming the shortcomings of traditional cemented lenses. Summary of the Invention

[0003] In view of the shortcomings of the existing technology, the purpose of this invention is to provide a high-quality wide-angle low-distortion lens to solve the problems existing in the background technology.

[0004] The above-mentioned technical objective of the present invention is achieved through the following technical solution: a high-quality wide-angle low-distortion lens, comprising: a first lens, a second lens, a third lens, and a fourth lens arranged sequentially along the optical axis from the object side to the image side; the first lens is a meniscus lens with negative optical power; the first lens is convex to the object side; the second lens is a biconvex lens with positive optical power; the third lens is a biconvex lens with positive optical power; the fourth lens is a meniscus lens with negative optical power; the fourth lens is convex to the image side; an aperture stop is disposed between the first lens and the second lens; the distance between the image plane of the third lens and the object plane of the fourth lens is 0.02 mm.

[0005] Optionally, the first lens has a d-ray refractive index Nd ≥ 1.535037 and an Abbe constant Vd ≥ 55.71.

[0006] Optionally, the second lens has a d-ray refractive index Nd ≤ 1.5928 and an Abbe constant Vd ≥ 68.34.

[0007] Optionally, the focal length F1 of the first lens and the focal length F of the high-quality wide-angle low-distortion lens satisfy the following relationship: 1.03≤|F1 / F|≤1.43.

[0008] Optionally, both the object plane and the image plane of the second lens are spherical, with the radius of curvature of the object plane of the second lens being 21.90 mm and the radius of curvature of the image plane of the second lens being 2.66 mm.

[0009] Optionally, a color filter is provided on the side of the fourth lens near the image side. The thickness of the color filter is 2.63 mm, and both the image plane and the object plane of the color filter are planar.

[0010] Optionally, the focal length F1 of the first lens and the focal length F2 of the second lens satisfy the following relationship: 0.64≤|F1 / F2|≤1.04.

[0011] In summary, the present invention has the following beneficial effects:

[0012] 1. The design structure of this invention avoids the high distortion phenomenon commonly found in traditional lenses. By rationally configuring the shape and refractive index of the lens, the geometric integrity of the image can be maintained at a wide angle of view, ensuring that the captured landscapes and objects are not distorted. At the same time, the non-cemented design avoids performance degradation caused by environmental changes (such as temperature and humidity). The lens can maintain stable optical performance and image quality under different usage conditions, solving the aging and optical degradation problems that may occur in cemented lenses during long-term use.

[0013] 2. The overall design makes the lens assembly easy to disassemble and clean. If a lens becomes dirty or moldy, it can be replaced individually without replacing the entire lens, which improves the maintainability of the product and reduces long-term usage costs. Because it does not use the complex structure of a cemented lens, this lens has a simpler design, a relatively smaller size, and is easy to carry, further increasing the lens's adaptability to different scenarios. Attached Figure Description

[0014] Figure 1 This is a schematic diagram of the lens structure of the present invention;

[0015] Figure 2 This is the lens optical path diagram of the present invention;

[0016] Figure 3 This is a color difference curve diagram of the optical performance curve of the present invention;

[0017] Figure 4 This is an astigmatism curve diagram of the optical performance curve of the present invention;

[0018] Figure 5 This is a distortion curve of the optical performance curve of the present invention;

[0019] Figure 6 This is the MTF curve of the optical performance curve of the present invention;

[0020] Figure 7 This is a wavefront distortion curve of the optical performance curve of the present invention. Detailed Implementation

[0021] To make the objectives, features, and advantages of the present invention more apparent and understandable, specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings. Several embodiments of the present invention are shown in the drawings. However, the present invention can be implemented in many different forms and is not limited to the embodiments described herein.

[0022] In this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances. The terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, a feature defined with "first" or "second" may explicitly or implicitly include one or more of that feature.

[0023] In this invention, unless otherwise expressly specified and limited, "above" or "below" a second feature can include direct contact between the first and second features, or contact between the first and second features through another feature between them. Furthermore, "above," "over," and "on top" of a second feature includes the first feature being directly above or diagonally above the second feature, or simply indicates that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" of a second feature includes the first feature being directly below or diagonally below the second feature, or simply indicates that the first feature is at a lower horizontal level than the second feature. The terms "vertical," "horizontal," "left," "right," "above," "below," and similar expressions are for illustrative purposes only and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed or operated in a specific orientation, and therefore should not be construed as limiting the invention.

[0024] The present invention will now be described in detail with reference to the accompanying drawings and embodiments.

[0025] This invention provides a high-quality wide-angle, low-distortion lens, such as... Figure 1As shown, it includes: a first lens, a second lens, a third lens, and a fourth lens arranged sequentially along the optical axis from the object side to the image side; the first lens is a meniscus lens with negative optical power; the first lens is convex towards the object side; the second lens is a biconvex lens with positive optical power; the third lens is a biconvex lens with positive optical power; the fourth lens is a meniscus lens with negative optical power; the fourth lens is convex towards the image side; an aperture is provided between the first lens and the second lens; the distance between the image plane of the third lens and the object plane of the fourth lens is 0.02 mm.

[0026] This invention employs an optical system composed of four reasonably matched lenses with different positive and negative optical powers and different concave and convex shapes, along with an aperture stop (STO). This system achieves the same imaging quality as using cemented lenses without requiring them. The resulting high-quality wide-angle, low-distortion lens has a total optical length (TTL) of 12.2mm, can withstand temperatures above 85 degrees Celsius, has over 3 million pixels, an ultra-wide angle of 146 degrees, low distortion (TV distortion only 16%), a large aperture (F / NO = 2.15), day / night confocal focusing capability, and offers excellent value for money (only 1G3P). The first lens is a glass lens, while the remaining lenses are plastic lenses.

[0027] Furthermore, the first lens has a d-ray refractive index Nd ≥ 1.535037 and an Abbe constant Vd ≥ 55.71.

[0028] Specifically, the first lens has good optical stability, is suitable for high-resolution imaging, can effectively reduce chromatic aberration caused by light refraction, ensure the detail and sense of layering of the image, and enhance the overall image quality.

[0029] Furthermore, the second lens has a d-ray refractive index Nd ≤ 1.5928 and an Abbe constant Vd ≥ 68.34.

[0030] Specifically, the second lens is designed with a biconvex shape. Through precise surface configuration, optical distortion can be effectively controlled, light convergence error can be reduced, the dispersion performance of the lens can be improved, and chromatic aberration and aberration can be reduced. This allows the image to maintain high-quality sharpness and balanced color performance even under extreme lighting conditions when shooting at a wide angle.

[0031] Furthermore, the focal length F1 of the first lens and the focal length F of the high-quality wide-angle low-distortion lens satisfy the following relationship: 1.03≤|F1 / F|≤1.43.

[0032] Specifically, the relationship between the focal length F1 of the first lens and the overall focal length F of the lens ensures that the lens has ideal perspective and clarity in wide-angle mode, reduces edge blur, and enables the entire image to achieve relatively consistent high imaging quality.

[0033] Furthermore, both the object plane and the image plane of the second lens are spherical, the radius of curvature of the object plane of the second lens is 21.90 mm, and the radius of curvature of the image plane of the second lens is 2.66 mm.

[0034] Specifically, the design of the second lens involves calculating and adjusting the required optical path to focus the light more precisely, ensuring optimal imaging results, reducing optical distortion, providing a more uniform defocus effect, and ensuring high-resolution images are obtained throughout the entire imaging range.

[0035] Furthermore, a color filter is provided on the side of the fourth lens near the image side. The thickness of the color filter is 2.63 mm, and both the image plane and the object plane of the color filter are planar.

[0036] Specifically, color filters are designed as flat surfaces to ensure that the paths of light entering and leaving are undisturbed. Appropriate materials are chosen for the color filters to minimize light loss.

[0037] Furthermore, the focal length F1 of the first lens and the focal length F2 of the second lens satisfy the following relationship: 0.64≤|F1 / F2|≤1.04.

[0038] Specifically, this setting ensures that the relationship between the focal length of the first lens and the focal length of the second lens maintains image quality while improving the optical performance of the lens, guaranteeing the optical alignment performance of the lens, reducing the error of light propagation between lenses, and improving the accuracy and clarity of imaging.

[0039] Optionally, it also includes: a lens barrel; the lens barrel is provided with a locking component for locking and limiting the third lens and the fourth lens so that the distance between the image plane of the third lens and the object plane of the fourth lens is maintained at 0.02 mm.

[0040] Specifically, the lens barrel design improves the stability of the lens's optical structure, enabling the lens to achieve the effect of a cemented lens without the need for cemented lenses. It also facilitates subsequent optical adjustments and effectively reduces imaging deviations caused by changes in lens spacing.

[0041] The high-quality wide-angle, low-distortion lens of the present invention will be specifically described below with reference to the above specific embodiments, the accompanying drawings, and tables.

[0042] The specific parameters that conform to the above lens relationship are as follows:

[0043] The first lens, the second lens, the third lens, and the fourth lens satisfy the following condition formula:

[0044] F1=-4.115997mm, F2=+4.888908mm,

[0045] F3=+2.907962mm, F4=-3.605768mm,

[0046] F = 3.35 mm.

[0047] F1-F4 represent the focal lengths of the first to fourth lenses, and F represents the effective focal length of the entire lens.

[0048] In embodiments of the present invention, such as Figure 1 As shown, with the object side as the base point, the first to fourth lenses along the optical axis are labeled L1 to L4 respectively. Then, the mirror surfaces of each lens are numbered sequentially. The mirror curvature radii of the first lens are R1 and R2, the aperture surface of the aperture is R3, the mirror curvature radii of the second lens are R4 and R5, the mirror curvature radii of the third lens are R6 and R7, the mirror curvature radii of the fourth lens are R8 and R9, and the lens of the color filter IR is R10 and R11.

[0049] The optical system parameters of this invention are shown in Table 1:

[0050] Table 1

[0051]

[0052] In Table 1, the Abbe constant Vd is given by Abbe number vd = (nd-1) / (nF-nC), where nd, nF, and nC are the refractive indices of D-ray, F-ray, and C-ray, respectively, and D-ray, F-ray, and C-ray are yellow light, cyan light, and red light, respectively.

[0053] Figure 2 This is the optical path diagram corresponding to this embodiment, i.e., a schematic diagram of the imaging process; Figures 3 to 7 For the optical performance curves corresponding to this embodiment, wherein Figure 3 This is a color difference curve, also known as a spherical aberration curve, which is indicated by the wavelengths of the commonly used F, D, and C colors of light, with the unit being nm. Figure 4 The astigmatism curve is represented by the wavelengths of the commonly used F, D, and C colors. Figure 5 This is a distortion curve graph, showing the magnitude of lens distortion at different field of view angles, in percentage (%). Figure 6 The MTF curve represents the overall resolution of the lens's optical system. Figure 7 This is a wavefront distortion curve, used to evaluate the imaging quality and diffraction characteristics of an optical system.

[0054] In the performance testing of the actual optical system of this invention, the optical specifications are as follows:

[0055] The total optical length TTL = 12.2 mm ± 0.2 mm;

[0056] Effective focal length (EFL) = 3.35mm ± 5%;

[0057] Aperture F / NO = 2.15 ± 5%;

[0058] Optical back focal length (BFL(O)) = 3.64 mm;

[0059] Mechanical back focus BFL(M) = 3.41mm;

[0060] The lens has a maximum field of view of 146°, and with an aperture setting of F22, the horizontal field of view is 134° and the vertical field of view is 110°.

[0061] In summary, considering the aforementioned optical specifications, Table 1, and... Figures 3-7 As shown, the high-quality wide-angle low-distortion lens of this embodiment can achieve the same imaging quality as a cemented lens without the need for a cemented lens. This results in a total optical length (TTL) of 12.2mm, the ability to withstand temperatures above 85 degrees Celsius, a pixel count of over 300W, an ultra-wide angle of 146 degrees, low distortion (TV distortion only 16%), a large aperture (F / NO=2.15), day / night confocal focusing capability, and high cost-effectiveness (only 1G3P). The first lens is a glass lens, while the remaining lenses are plastic lenses. In contrast, achieving the same effect as this invention traditionally requires 5G.

[0062] The above description is merely a preferred embodiment of the present invention. The scope of protection of the present invention is not limited to the above embodiments. All technical solutions falling within the scope of the present invention's concept are within the scope of protection of the present invention. It should be noted that for those skilled in the art, any improvements and modifications made without departing from the principles of the present invention should also be considered within the scope of protection of the present invention.

Claims

1. A high-quality wide-angle, low-distortion lens, characterized in that, It consists of a first lens, a second lens, a third lens, and a fourth lens arranged sequentially along the optical axis from the object side to the image side; The first lens is a meniscus lens with negative optical power; the first lens is convex to the object side; the second lens is a concave-convex lens with positive optical power, its object side is concave and its image side is convex; the third lens is a biconvex lens with positive optical power; the fourth lens is a meniscus lens with negative optical power; the fourth lens is convex to the image side. An aperture stop is provided between the first lens and the second lens; the distance between the image plane of the third lens and the object plane of the fourth lens is 0.02 mm; the third lens and the fourth lens are fixed by a non-cementing method; The first lens has a d-ray refractive index Nd ≥ 1.535037 and an Abbe constant Vd ≥ 55.71; The second lens has a d-ray refractive index Nd ≤ 1.5928 and an Abbe constant Vd ≥ 68.34; The focal length F1 of the first lens and the focal length F of the high-quality wide-angle low-distortion lens satisfy the following relationship: 1.03≤|F1 / F|≤1.43; The object plane and the image plane of the second lens are both spherical. The radius of curvature of the object plane of the second lens is -21.89 mm, and the radius of curvature of the image plane is -2.66 mm.

2. The high-quality wide-angle low-distortion lens according to claim 1, characterized in that, A color filter is provided on the side of the fourth lens near the image side. The thickness of the color filter is 2.63 mm, and both the image plane and the object plane of the color filter are planar.

3. The high-quality wide-angle low-distortion lens according to claim 1, characterized in that, The focal length F1 of the first lens and the focal length F2 of the second lens satisfy the following relationship: 0.64≤|F1 / F2|≤1.04.

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