High-quality wide-angle low-distortion lens

Abstract

The invention relates to the technical field of imaging optics, in particular to a high-quality wide-angle low-distortion lens, which can realize imaging quality by using a glued lens without using the glued lens, so that the total optical length TTL of the high-quality wide-angle low-distortion lens is 12.2 mm, the high-quality wide-angle low-distortion lens can resist high temperature of more than 85 DEG C, the lens pixel is more than 300W, and the high-quality wide-angle low-distortion lens has the advantages of ultra-wide-angle opposite angle of 146 degrees, low distortion degree and high resolution. The TV distortion is only 16%, the large aperture F / NO is 2.15, the lens has a day-night confocal function, the cost performance of the lens is high and is only 1G3P, the first lens is a glass lens, the other lenses are plastic lenses, and 5G is needed for achieving the effect of the invention traditionally.

Description

Technical Field

[0001] The present invention relates to the field of imaging optical technology, and more particularly to a high-quality wide-angle low-distortion lens. Background Art

[0002] With the development of lens and electronic technology, lens is no longer limited to camera system. In addition to traditional DV shooting, lens is also used in various other video acquisition environments; for example, the monitoring system shoots the surrounding environment, various vehicle devices including passenger cars, trucks, motorcycles, etc.; existing traditional lenses, such as the wide-angle low-distortion lens with patent publication number CN115113376A, often use glued lens in the lens to ensure the image quality. The glued lens is made by gluing multiple optical elements during the manufacturing process to reduce the size of the lens and improve the optical performance; however, this structure has defects such as optical performance degradation, internal contamination, and difficulty in cleaning and repair under the condition of temperature changes, humidity fluctuations and long-term use; therefore, a new lens design is urgently needed to meet the imaging quality of the glued lens without gluing the lens, so as to solve the shortcomings of the traditional glued lens. Summary of the invention

[0003] In view of the shortcomings of the prior art, an object of the present invention is to provide a high-quality wide-angle low-distortion lens to solve the problems existing in the above-mentioned background technology.

[0004] The above technical objectives of the present invention are achieved through the following technical solutions: a high-quality wide-angle low-distortion lens, comprising: a first lens, a second lens, a third lens and a fourth lens arranged in sequence along the optical axis from the object side to the image side; the first lens is a meniscus lens with negative optical focal length; the first lens is convex to the object side; the second lens is a biconvex lens with positive optical focal length; the third lens is a biconvex lens with positive optical focal length; the fourth lens is a meniscus lens with negative optical focal length; the fourth lens is convex to the image side; an aperture member 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.

[0005] Optionally, the d-light refractive index Nd of the first lens is ≥1.535037, and the Abbe constant Vd is ≥55.71.

[0006] Optionally, the d-light refractive index Nd of the second lens is ≤1.5928, and the Abbe constant Vd is ≥68.34.

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

[0008] Optionally, both the object surface of the second lens and the image surface of the second lens are spherical surfaces, the curvature radius of the object surface of the second lens is 21.90 mm, and the curvature radius of the image surface of the second lens is 2.66 mm.

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

[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 the present invention avoids the high distortion phenomenon commonly seen 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 viewing angle, so that the captured scenery and objects are not distorted. At the same time, the non-glued design is adopted to avoid performance degradation caused by environmental changes (such as temperature and humidity). The lens can still maintain stable optical performance and image quality under different use conditions, solving the aging and optical degradation problems that may occur in glued lenses during long-term use.

[0013] 2. The overall design makes the lens assembly easy to disassemble and clean. If one of the lenses is dirty or moldy, it can be replaced individually without replacing the entire lens, which improves the maintainability of the product and reduces the long-term use cost. Since the complex structure of the glued lens is not used, this lens is simpler in design, relatively small in size, and easy to carry, which further increases the scene adaptability of the lens. BRIEF DESCRIPTION OF THE DRAWINGS

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

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

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

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

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

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

[0020] Figure 7 It is a wavefront distortion curve diagram of the optical performance curve of the present invention. DETAILED DESCRIPTION

[0021] In order to make the purpose, features and advantages of the present invention more obvious and easy to understand, the specific implementation methods of the present invention are described in detail below in conjunction with the accompanying drawings. Several embodiments of the present invention are shown in the accompanying drawings. However, the present invention can be implemented in many different forms and is not limited to the embodiments described herein.

[0022] In the present invention, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal connection of two elements. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to the specific circumstances. The terms "first" and "second" are used for descriptive purposes only and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features.

[0023] In the present invention, unless otherwise clearly specified and limited, the first feature being "above" or "below" the second feature may include the first and second features being in direct contact, or may include the first and second features being in contact not directly but through another feature between them. Moreover, the first feature being "above", "above" and "above" the second feature includes the first feature being directly above and obliquely above the second feature, or simply indicates that the first feature is higher in level than the second feature. The first feature being "below", "below" and "below" the second feature includes the first feature being directly below and obliquely below the second feature, or simply indicates that the first feature is lower in 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 and operated in a specific orientation, and therefore should not be understood as limiting the present invention.

[0024] The present invention is described in detail below in conjunction with the accompanying drawings and embodiments.

[0025] The present 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 in sequence along the optical axis from the object side to the image side; the first lens is a meniscus lens with negative optical focal length; the first lens is convex to the object side; the second lens is a biconvex lens with positive optical focal length; the third lens is a biconvex lens with positive optical focal length; the fourth lens is a meniscus lens with negative optical focal length; the fourth lens is convex to the image side; an aperture member 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] The embodiment of the present invention adopts the above-mentioned four reasonably matched lenses with different positive and negative optical powers and different concave and convex shapes and an optical system composed of an aperture member STO. Without the need to use a cemented lens, the imaging quality of the cemented lens can also be achieved, so that the total optical length TTL of the high-quality wide-angle low-distortion lens is 12.2mm, it can withstand high temperatures above 85 degrees, the lens pixels are above 300W, it has an ultra-wide-angle angle of 146 degrees, low distortion, TV distortion of only 16%, a large aperture F / NO=2.15, a day and night confocal function, a high cost-effective lens, only 1G3P, wherein the first lens is a glass lens, and the remaining lenses are plastic lenses.

[0027] Furthermore, the d-light refractive index Nd of the first lens is ≥1.535037, and the Abbe constant Vd is ≥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, ensures imaging details and layering, and enhances the overall image quality.

[0029] Furthermore, the d-light refractive index Nd of the second lens is ≤1.5928, and the Abbe constant Vd is ≥68.34.

[0030] Specifically, the design of the second lens adopts a biconvex form. Through precise curved surface configuration, it can effectively control optical distortion, reduce light convergence error, improve the dispersion performance of the lens, and reduce chromatic aberration and aberration, so that when shooting at wide angles, even under extreme lighting conditions, the image can still maintain high-quality clarity and balanced color performance.

[0031] Furthermore, the focal length F1 of the first lens and the focal length F of the high-quality wide-angle and 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 can ensure that the lens has an ideal perspective effect and clarity in a wide-angle state, reduce edge blur, and enable the entire picture to achieve relatively consistent high imaging quality.

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

[0034] Specifically, the design of the second lens is based on the required optical path adjustment, so that the light can be focused more accurately and the best imaging effect can be guaranteed, so as to reduce optical distortion, provide a more uniform defocus effect, and ensure that high-resolution images can be obtained within the entire imaging range.

[0035] Furthermore, a color filter is provided on a side of the fourth lens close to 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 flat.

[0036] Specifically, the color filter is designed to be flat to ensure that the path of light entering and leaving is not disturbed. The color filter is made of suitable materials to minimize the loss of light by the color filter.

[0037] Further, 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 arrangement improves the optical performance of the lens while maintaining image quality, ensures the optical alignment performance of the lens, reduces the error of light propagation between lenses, and improves the accuracy and clarity of imaging.

[0039] Optionally, it also includes: a lens barrel; the lens barrel is provided with: a clamping component for clamping 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 design of the lens barrel improves the stability of the optical structure of the lens, so that the effect of a glued lens can be achieved without using a glued lens, and also provides convenience for subsequent optical adjustment, which can effectively reduce the imaging deviation caused by changes in lens spacing.

[0041] The high-quality wide-angle and low-distortion lens of the present invention is described in detail below with reference to the above specific embodiments in combination with the accompanying drawings and tables.

[0042] The parameters that specifically 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 conditional formula:

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

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

[0046] F=3.35mm.

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

[0048] In an embodiment of the present invention, Figure 1 As shown, taking the object side as the base point, the first lens to the fourth lens along the optical axis direction are marked as L1 to L4, and then the mirror surfaces of each lens are numbered in turn, the mirror curvature radius of the first lens is R1, R2, the aperture surface of the aperture member is R3, the mirror curvature radius of the second lens is R4, R5, the mirror curvature radius of the third lens is R6, R7, the mirror curvature radius of the fourth lens is R8, R9, and the lens of the color filter IR is R10, R11.

[0049] The optical system parameter table of the present invention is shown in Table 1:

[0050] Table 1

[0051]

[0052] The Abbe constant Vd in Table 1, Abbe number vd = (nd-1) / (nF-nC), wherein nd, nF and nC are the refractive indices of D light, F light and C light respectively, and D light, F light and C light are yellow light, cyan light and red light respectively.

[0053] Figure 2 is a light path diagram corresponding to this embodiment, that is, a schematic diagram of the imaging process; Figures 3 to 7 is an optical performance curve corresponding to this embodiment, wherein Figure 3 It is a chromatic aberration curve, also known as a spherical aberration curve, which is indicated by the wavelengths of the three commonly used colors F, D, and C, and the unit is nm; Figure 4 It is an astigmatism curve diagram, indicated by the wavelengths of the three commonly used colors F, D, and C; Figure 5 It is a distortion curve diagram, which shows the distortion value of the lens under different field of view angles, in %. Figure 6 It is an MTF curve, which represents the comprehensive resolution level of the lens' optical system; Figure 7 It is a wavefront distortion curve, which is used to evaluate the imaging quality and diffraction characteristics of the optical system.

[0054] During the performance test of the actual optical system of the present invention, the optical specifications are:

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

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

[0057] Aperture F / NO=2.15±5%;

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

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

[0060] The lens field of view has a maximum angle of 146°. When the aperture is set to F22, the horizontal field of view is 134° and the vertical field of view is 110°.

[0061] In summary, combined with the above optical specifications, Table 1 and Figure 3-Figure 7 As shown, the high-quality wide-angle low-distortion lens of this embodiment can also achieve the imaging quality of using a cemented lens without using a cemented lens, so that the total optical length TTL of the high-quality wide-angle low-distortion lens is 12.2mm, it can withstand high temperatures above 85 degrees, the lens pixel is more than 300W, it has an ultra-wide-angle angle of 146 degrees, low distortion, TV distortion of only 16%, a large aperture F / NO=2.15, and a day and night confocal function. The lens has a high cost performance ratio and is only 1G3P, wherein the first lens is a glass lens and the remaining lenses are plastic lenses, while the traditional method requires 5G to achieve the effect achieved by the present invention.

[0062] The above is only a preferred embodiment of the present invention, and the protection scope of the present invention is not limited to the above embodiments. All technical solutions under the concept of the present invention belong to the protection scope of the present invention. It should be pointed out that for ordinary technicians in this technical field, some improvements and modifications without departing from the principle of the present invention should also be regarded as the protection scope of the present invention.

Claims

1. A high-quality wide-angle low-distortion lens, characterized in that: include: A first lens, a second lens, a third lens and a fourth lens are arranged in sequence along the optical axis from the object side to the image side; The first lens is a meniscus lens with negative power; the first lens is convex to the object side; the second lens is a biconvex lens with positive power; the third lens is a biconvex lens with positive power; the fourth lens is a meniscus lens with negative power; the fourth lens is convex to the image side; An aperture member is arranged between the first lens and the second lens; and a distance between the image plane of the third lens and the object plane of the fourth lens is 0.02 mm.

2. The high-quality wide-angle low-distortion lens according to claim 1, characterized in that: The d-light refractive index Nd of the first lens is ≥1.535037, and the Abbe constant Vd is ≥55.

71.

3. The high-quality wide-angle low-distortion lens according to claim 2, characterized in that: The d-light refractive index Nd of the second lens is ≤1.5928, and the Abbe constant Vd is ≥68.

34.

4. 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 F of the high-quality wide-angle and low-distortion lens satisfy the following relationship: 1.03≤|F1 / F|≤1.

43.

5. The high-quality wide-angle low-distortion lens according to claim 1, characterized in that: The object surface of the second lens and the image surface of the second lens are both spherical surfaces. The curvature radius of the object surface of the second lens is 21.90 mm, and the curvature radius of the image surface of the second lens is 2.66 mm.

6. The high-quality wide-angle low-distortion lens according to claim 1, characterized in that: A color filter is arranged on the side of the fourth lens close to the image side, the thickness of the color filter is 2.63 mm, and both the image surface and the object surface of the color filter are planes.

7. 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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