Optical lens

Abstract

The application provides an optical lens, which comprises six lenses in sequence from an object side to an imaging surface along an optical axis, and the six lenses comprise: a first lens with negative optical power, wherein the object side surface of the first lens is a concave surface and the image side surface of the first lens is a convex surface; a second lens with positive optical power, wherein the image side surface of the second lens is a convex surface; a third lens with positive optical power, wherein the object side surface of the third lens is a concave surface and the image side surface of the third lens is a convex surface; a fourth lens with negative optical power, wherein the object side surface and the image side surface of the fourth lens are both concave surfaces; a fifth lens with positive optical power, wherein the object side surface and the image side surface of the fifth lens are both convex surfaces; and a sixth lens with negative optical power, wherein the object side surface of the sixth lens is a concave surface. The optical lens provided by the application has one or more advantages, such as low cost, high resolution and high imaging quality, by specific surface shape matching and reasonable optical power distribution.

Description

Technical Field

[0001] This invention relates to the technical field of imaging lenses, and in particular to an optical lens. Background Technology

[0002] In modern automotive technology, in-vehicle cameras play a crucial role. These cameras come in various types, such as interior, rear, front, side, and surround-view cameras, each with its unique application scenarios. For example, rear-view cameras are primarily used for reversing imaging, while surround-view cameras provide a 360-degree panoramic view, greatly enhancing the driver's perception.

[0003] In automotive cameras, the forward-facing camera is a core component of ADAS (Advanced Driver Assistance Systems). It is typically mounted on the windshield and primarily responsible for functions such as forward collision warning, lane departure warning, and pedestrian detection. Currently, due to the complex algorithms and chip processing involved, forward-facing cameras are generally much more expensive than other types of cameras, reflecting their crucial role in automotive camera systems. With the rapid development of advanced driver assistance systems, the requirements for forward-facing lenses are also increasing. Therefore, there is a need to develop an optical lens with high imaging quality. Summary of the Invention

[0004] To address the aforementioned problems, the present invention aims to provide an optical lens with the advantage of excellent image quality.

[0005] The technical solution adopted in this invention is as follows:

[0006] An optical lens comprises six lenses, arranged sequentially along the optical axis from the object side to the imaging plane:

[0007] The first lens with negative optical power has a concave object side and a convex image side.

[0008] A second lens with positive optical power has a convex image-side surface.

[0009] A third lens with positive optical power has a concave object side and a convex image side.

[0010] The fourth lens with negative optical power has concave object-side and image-side surfaces;

[0011] The fifth lens with positive optical power has convex surfaces on both its object side and image side.

[0012] The sixth lens has negative optical power and its object side is concave.

[0013] Wherein, the radius of curvature R2 of the image side of the first lens and the effective focal length f of the optical lens satisfy: R2 / f<-3.

[0014] More preferably, the focal length f1 of the first lens and the effective focal length f of the optical lens satisfy: -5.9 < f1 / f < -2.9.

[0015] More preferably, the focal length f6 of the sixth lens and the effective focal length f of the optical lens satisfy: -4.5 < f6 / f < -0.8.

[0016] More preferably, the combined focal length f12 of the first lens and the second lens and the effective focal length f of the optical lens satisfy: 0.9 < f12 / f < 1.6.

[0017] More preferably, the radius of curvature R2 of the image side of the first lens and the focal length f1 of the first lens satisfy: 1.5 < R2 / f1 < 2.9.

[0018] More preferably, the radius of curvature R4 of the image side of the second lens and the focal length f2 of the second lens satisfy: -3.9 < R4 / f2 < -0.3; the radius of curvature R11 of the object side of the sixth lens and the focal length f6 of the sixth lens satisfy: 0 < R11 / f6 < 2.5.

[0019] More preferably, the radius of curvature R5 of the object side of the third lens and the focal length f3 of the third lens satisfy: -5.2 < R5 / f3 < -1.9; the radius of curvature R7 of the object side of the fourth lens and the focal length f4 of the fourth lens satisfy: 1.9 < R7 / f4 < 13.4.

[0020] More preferably, the true image height IH corresponding to the maximum field angle of the optical lens, the effective focal length f of the optical lens, and the radian θ of the maximum half field angle of the optical lens satisfy: 0.88 < (IH / 2) / (f×θ) < 1.00.

[0021] More preferably, the maximum field angle FOV of the optical lens, the effective focal length f of the optical lens, and the true image height IH corresponding to the maximum field angle of the optical lens satisfy: 60° < FOV×f / IH < 70°.

[0022] More preferably, the clear aperture semi-diameter d2 of the image side of the first lens and the sagittal height Sag2 of the clear aperture of the image side of the first lens satisfy: -0.1 < Sag2 / d2 < 0; the center-to-center distance CT12 of the first lens and the second lens on the optical axis and the center-to-center distance CT23 of the second lens and the third lens on the optical axis satisfy: CT12 / CT23 > 15.

[0023] The optical lens provided by this invention uses six lenses with specific optical power. Through specific surface shape matching and reasonable optical power distribution, it can improve the imaging quality of the optical lens, reduce aberrations, and enhance the imaging quality of the optical lens, giving the lens one or more advantages such as low cost, high resolution, and high imaging quality. Attached Figure Description

[0024] The above and / or additional aspects and advantages of the present invention will become apparent and readily understood from the description of the embodiments taken in conjunction with the following drawings, in which:

[0025] Figure 1 This is a schematic diagram of the optical lens structure in Embodiment 1 of the present invention.

[0026] Figure 2 This is a field curvature curve diagram of the optical lens in Embodiment 1 of the present invention.

[0027] Figure 3 This is the F-θ distortion curve of the optical lens in Embodiment 1 of the present invention.

[0028] Figure 4 This is an axial aberration curve of the optical lens in Embodiment 1 of the present invention.

[0029] Figure 5 This is a chromatic aberration curve of the optical lens in Embodiment 1 of the present invention.

[0030] Figure 6 This is an MTF curve of the optical lens in Embodiment 1 of the present invention.

[0031] Figure 7 This is a schematic diagram of the optical lens structure in Embodiment 2 of the present invention.

[0032] Figure 8 This is a field curvature curve diagram of the optical lens in Embodiment 2 of the present invention.

[0033] Figure 9 This is the F-θ distortion curve of the optical lens in Embodiment 2 of the present invention.

[0034] Figure 10 This is an axial aberration curve of the optical lens in Embodiment 2 of the present invention.

[0035] Figure 11 This is a chromatic aberration curve of the optical lens in Embodiment 2 of the present invention.

[0036] Figure 12 This is the MTF curve of the optical lens in Embodiment 2 of the present invention.

[0037] Figure 13 This is a schematic diagram of the optical lens in Embodiment 3 of the present invention.

[0038] Figure 14 This is a field curvature curve diagram of the optical lens in Embodiment 3 of the present invention.

[0039] Figure 15 This is the F-θ distortion curve of the optical lens in Embodiment 3 of the present invention.

[0040] Figure 16 This is an axial aberration curve of the optical lens in Embodiment 3 of the present invention.

[0041] Figure 17 This is a chromatic aberration curve of the optical lens in Embodiment 3 of the present invention.

[0042] Figure 18 This is an MTF curve of the optical lens in Embodiment 3 of the present invention.

[0043] The following detailed description, in conjunction with the accompanying drawings, will further illustrate the present invention. Detailed Implementation

[0044] To better understand this application, various aspects of this application will be described in more detail with reference to the accompanying drawings. It should be understood that these detailed descriptions are merely illustrative of embodiments of this application and are not intended to limit the scope of this application in any way. Throughout the specification, the same reference numerals refer to the same elements. The expression "and / or" includes any and all combinations of one or more of the associated listed items.

[0045] It should be noted that in this specification, the terms "first," "second," "third," etc., are used only to distinguish one feature from another and do not imply any limitation on the features. Therefore, without departing from the teachings of the invention, the first lens discussed below may also be referred to as the second lens or the third lens.

[0046] In the accompanying drawings, the thickness, size, and shape of the lenses have been slightly exaggerated for ease of illustration. Specifically, the shapes of the spherical or aspherical surfaces shown in the drawings are illustrated by way of example. That is, the shapes of the spherical or aspherical surfaces are not limited to those shown in the drawings. The drawings are for illustrative purposes only and are not strictly to scale.

[0047] In this article, "near the optical axis" refers to the region near the optical axis. If the lens surface is convex and its location is not defined, it means that the lens surface is convex at least near the optical axis; if the lens surface is concave and its location is not defined, it means that the lens surface is concave at least near the optical axis. The surface of each lens closest to the subject is called the object-side surface of the lens, and the surface of each lens closest to the imaging plane is called the image-side surface of the lens.

[0048] It should also be understood that the terms "comprising," "including," "having," "containing," and / or "comprising," when used in this specification, indicate the presence of the stated features, elements, and / or components, but do not exclude the presence or addition of one or more other features, elements, components, and / or combinations thereof. Furthermore, when expressions such as "at least one of..." appear after a list of listed features, they modify the entire list of features, not individual elements in the list. Additionally, when describing embodiments of this application, the word "may" is used to mean "one or more embodiments of this application." And the term "exemplary" is intended to refer to an example or illustration.

[0049] Unless otherwise specified, all terms used herein (including technical and scientific terms) shall have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains. It should also be understood that terms (e.g., those defined in common dictionaries) shall be interpreted as having the meaning consistent with their meaning in the context of the relevant art and shall not be interpreted in an idealized or overly formal sense unless expressly so specified herein.

[0050] It should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other. This application will now be described in detail with reference to the accompanying drawings and embodiments.

[0051] The optical lens provided in this embodiment of the invention consists of six lenses, which are arranged sequentially from the object side to the imaging plane along the optical axis as a first lens, a second lens, a third lens, a fourth lens, a fifth lens, and a sixth lens.

[0052] In some embodiments, the first lens may have negative optical power, with its object-side surface being concave and its image-side surface being convex. The second lens may have positive optical power, with its image-side surface being convex. The third lens may have positive optical power, with its object-side surface being concave and its image-side surface being convex. The fourth lens may have negative optical power, with both its object-side and image-side surfaces being concave. The fifth lens may have positive optical power, with both its object-side and image-side surfaces being convex. The sixth lens may have negative optical power, with its object-side surface being concave and its image-side surface being either convex or concave.

[0053] In some embodiments, the second lens has positive optical power and its object-side surface is convex; the sixth lens has negative optical power and its image-side surface is concave.

[0054] In some embodiments, the second lens has positive optical power and its object side is concave; the sixth lens has negative optical power and its image side is convex.

[0055] In some embodiments, the optical lens may further include an aperture, which may be located between the second lens and the third lens. It can be understood that the aperture can be used to limit the amount of incident light to change the brightness of the image. Additionally, when the aperture is located between the second lens and the third lens, the aperture can reasonably distribute the functions of the first lens to the sixth lens. For example, the first lens and the second lens can be used to receive light to a greater extent, and the third lens to the sixth lens can be used to correct aberrations, which is beneficial to balancing the structure of the entire optical system. Furthermore, when the aperture is located between the second lens and the third lens, it is convenient to correct the aperture aberration.

[0056] In some embodiments, the optical lens may further include a filter and a protective glass, which may be sequentially arranged along the optical axis between the sixth lens and the imaging surface. The filter is used to filter out interfering light to prevent the interfering light from reaching the imaging surface of the optical lens and affecting normal imaging. The protective glass plays a role in protecting the optical lens, preventing the photosensitive chip from being damaged, and can improve the anti-impact and scratch-resistant capabilities of the optical lens, while having almost no impact on the imaging quality of the optical lens.

[0057] In some embodiments, the radius of curvature R2 of the image side surface of the first lens and the effective focal length f of the optical lens satisfy: R2 / f < -3. Meeting the above range and reasonably defining the radius of curvature of the image side surface of the first lens and the effective focal length of the optical lens can control the light direction, increase the depth of field, reduce spherical aberration, correct coma, increase the light utilization rate, and improve stability. Preferably, -8.8 < R2 / f < -8.3.

[0058] In some embodiments, the focal length f1 of the first lens and the effective focal length f of the optical lens satisfy: -5.9 < f1 / f < -2.9. Meeting the above range gives the first lens an appropriate negative optical power to achieve large-angle light collection; at the same time, it is beneficial to reduce the inclination angle of the incident light and reduce the generation of high-order aberrations. Preferably, -5.4 < f1 / f < -3.2.

[0059] In some embodiments, the focal length f6 of the sixth lens and the effective focal length f of the optical lens satisfy: -4.5 < f6 / f < -0.8. Meeting the above range gives the sixth lens an appropriate negative optical power, which can increase the imaging area and improve the imaging quality. Preferably, -4.2 < f6 / f < -1.1.

[0060] In some embodiments, the combined focal length f12 of the first lens and the second lens and the effective focal length f of the optical lens satisfy: 0.9 < f12 / f < 1.6. Meeting the above range makes the optical power of the front lens group of the optical lens within an appropriate range, which can converge light, reduce the difficulty of lens aberration correction, and improve the imaging quality of the optical lens. Preferably, 1.1 < f12 / f < 1.5.

[0061] In some embodiments, the radius of curvature R2 of the image side surface of the first lens and the focal length f1 of the first lens satisfy: 1.5 < R2 / f1 < 2.9. Satisfying the above range and reasonably defining the radius of curvature of the image side surface of the first lens and the focal length of the first lens can reduce the difficulty of aberration correction of the rear lens. Preferably, 1.6 < R2 / f1 < 2.8.

[0062] In some embodiments, the radius of curvature R4 of the image side surface of the second lens and the focal length f2 of the second lens satisfy: -3.9 < R4 / f2 < -0.3; the radius of curvature R11 of the object side surface of the sixth lens and the focal length f6 of the sixth lens satisfy: 0 < R11 / f6 < 2.5. Satisfying the above range and reasonably defining the radius of curvature of the image side surface of the second lens and the focal length of the second lens, as well as the radius of curvature of the object side surface of the sixth lens and the focal length of the sixth lens, can effectively reduce astigmatism and improve the resolution of the optical lens. Preferably, -3.2 < R4 / f2 < -0.7; 0 < R11 / f6 < 2.3.

[0063] In some embodiments, the radius of curvature R5 of the object side surface of the third lens and the focal length f3 of the third lens satisfy: -5.2 < R5 / f3 < -1.9; the radius of curvature R7 of the object side surface of the fourth lens and the focal length f4 of the fourth lens satisfy: 1.9 < R7 / f4 < 13.4. Satisfying the above range and reasonably defining the radius of curvature of the object side surface of the third lens and the focal length of the third lens, as well as the radius of curvature of the object side surface of the fourth lens and the focal length of the fourth lens, can reduce the distortion generated by the first lens, reduce the requirements for distortion correction of the front lens, and improve the imaging quality of the optical lens. Preferably, -4.9 < R5 / f3 < -2.3; 2.2 < R7 / f4 < 11.5.

[0064] In some embodiments, the true image height IH corresponding to the maximum field angle of the optical lens, the effective focal length f of the optical lens, and the radian θ of the maximum half field angle of the optical lens satisfy: 0.88 < (IH / 2) / (f×θ) < 1.00. Satisfying the above range is beneficial to achieving the balance between a large image plane and high-quality imaging of the optical lens, enabling the lens to have a large imaging area and at the same time having higher resolution ability. Preferably, 0.88 < (IH / 2) / (f×θ) < 0.92.

[0065] In some embodiments, the maximum field angle FOV of the optical lens, the effective focal length f of the optical lens, and the true image height IH corresponding to the maximum field angle of the optical lens satisfy: 60° < FOV×f / IH < 70°. Satisfying the above range and reasonably controlling the field angle, focal length, and true image height of the optical lens within a reasonable range can improve the imaging quality of the lens while meeting the specification requirements. Preferably, 63.2° < FOV×f / IH < 64.4°.

[0066] In some embodiments, the clear aperture semi-diameter d2 of the image side of the first lens and the sagittal height Sag2 of the clear aperture of the image side of the first lens satisfy: -0.1 < Sag2 / d2 < 0; the center-to-center distance CT12 between the first lens and the second lens on the optical axis and the center-to-center distance CT23 between the second lens and the third lens on the optical axis satisfy: CT12 / CT23 > 15. Meeting the above ranges and reasonably defining the clear aperture semi-diameter of the image side of the second lens and the corresponding sagittal height of the clear aperture can effectively control the light path of the marginal field of view and improve the imaging quality of the marginal field of view; reasonably configuring the center-to-center distance between the first lens and the second lens and the center-to-center distance between the second lens and the third lens is beneficial to meeting the processability and manufacturability requirements of the lens, reducing the assembly difficulty, and improving the yield. Preferably, -0.07 < Sag2 / d2 < -0.03; 15.5 < CT12 / CT23 < 39.2.

[0067] In some embodiments, the overall optical length TTL of the optical lens and the true image height IH corresponding to the maximum field angle of the optical lens satisfy: 3.1 < TTL / IH < 4.3. Meeting the above range is beneficial to achieving the balance of a small volume and a large image plane of the optical lens, enabling the lens to have a smaller overall length while having higher resolution ability. Preferably, 3.3 < TTL / IH < 4.0.

[0068] In some embodiments, the maximum field angle FOV of the optical lens and the f-number FNO of the optical lens satisfy: 35° < FOV / FNO < 42°. Meeting the above range is beneficial to expanding the field angle of the optical lens and increasing the aperture of the optical lens, facilitating the optical lens to obtain more scene information and meeting the requirements of large-range detection. The realization of the large-aperture characteristic is beneficial to improving the problem of rapid decline of the relative brightness of the marginal field of view, and thus is also beneficial to obtaining more scene information. Preferably, 38.6° < FOV / FNO < 39.8°.

[0069] In some embodiments, the true image height IH corresponding to the maximum field angle of the optical lens and the entrance pupil diameter EPD of the optical lens satisfy: 1.7 < IH / EPD < 2.1. Meeting the above range can increase the width of the light beam entering the optical lens, improving the brightness at the image plane of the optical lens and avoiding vignetting. Preferably, 1.8 < IH / EPD < 2.0.

[0070] In some embodiments, the back focal length BFL of the optical lens and the effective focal length f of the optical lens satisfy: BFL / f > 0.3. Meeting the above range reduces the interference of aberrations such as spherical aberration and coma, improving the resolution and clarity of imaging; improving the stability of the optical lens. Preferably, 0.31 < BFL / f < 0.36.

[0071] In some embodiments, the focal length f2 of the second lens and the effective focal length f of the optical lens satisfy: 0.9 < f2 / f < 1.7. Meeting the above range enables the second lens to have an appropriate positive optical power, which can converge light and make the light trend stable. Preferably, 1.1 < f2 / f < 1.6.

[0072] In some embodiments, the focal length f3 of the third lens and the effective focal length f of the optical lens satisfy: 1.2 < f3 / f < 3.4. Meeting the above range enables the third lens to have an appropriate positive optical power, which can balance lens aberrations and improve imaging quality. Preferably, 1.5 < f3 / f < 3.2.

[0073] In some embodiments, the focal length f4 of the fourth lens and the effective focal length f of the optical lens satisfy: -0.9 < f4 / f < -0.4. Meeting the above range enables the fourth lens to have an appropriate negative optical power, which can optimize lens chromatic aberration and improve imaging quality. Preferably, -0.8 < f4 / f < -0.5.

[0074] In some embodiments, the focal length f5 of the fifth lens and the effective focal length f of the optical lens satisfy: 0.5 < f5 / f < 0.9. Meeting the above range enables the fifth lens to have an appropriate positive optical power, which can optimize spherical aberration and achieve high-quality imaging. Preferably, 0.6 < f5 / f < 0.8.

[0075] In some embodiments, the combined focal length f12 of the first lens and the second lens and the combined focal length f3456 of the third lens, the fourth lens, the fifth lens and the sixth lens satisfy: -0.5 < f12 / f3456 < 0.9. Meeting the above range enables the optical powers of the front and rear lens groups of the optical lens to be within an appropriate range, which can converge light, reduce the difficulty of lens aberration correction, and improve the imaging quality of the optical lens. Preferably, -0.2 < f12 / f3456 < 0.4.

[0076] In some embodiments, the curvature radius R5 of the object side surface of the third lens and the effective focal length f of the optical lens satisfy: -8.3 < R5 / f < -6.5; the curvature radius R7 of the object side surface of the fourth lens and the effective focal length f of the optical lens satisfy: -7.9 < R7 / f < -0.9. Meeting the above range can reasonably limit the curvature radius of the object side surface of the third lens and the effective focal length of the optical lens, as well as the curvature radius of the object side surface of the fourth lens and the effective focal length of the optical lens, which can reduce astigmatism and spherical aberration and improve imaging quality. Preferably, -7.8 < R5 / f < -7.4; -7.4 < R7 / f < -1.2.

[0077] In some embodiments, the radius of curvature R2 of the image side of the first lens and the radius of curvature R5 of the object side of the third lens satisfy: 0.9 < R2 / R5 < 1.3. Satisfying the above range and reasonably controlling the radius of curvature of the image side of the first lens and the radius of curvature of the object side of the third lens helps to improve the imaging quality. Preferably, 1.0 < R2 / R5 < 1.2.

[0078] In some embodiments, the radius of curvature R2 of the image side of the first lens and the radius of curvature R7 of the object side of the fourth lens satisfy: 1.0 < R2 / R7 < 7.9. Satisfying the above range and reasonably controlling the radius of curvature of the image side of the first lens and the radius of curvature of the object side of the fourth lens helps to improve the imaging quality. Preferably, 1.1 < R2 / R7 < 7.2.

[0079] In some embodiments, the radius of curvature R5 of the object side of the third lens and the radius of curvature R7 of the object side of the fourth lens satisfy: 0.9 < R5 / R7 < 6.8. Satisfying the above range and reasonably controlling the radius of curvature of the object side of the third lens and the radius of curvature of the object side of the fourth lens helps to improve the imaging quality. Preferably, 1.0 < R5 / R7 < 6.2.

[0080] In some embodiments, the semi-aperture d5 of the light passing through the object side of the third lens and the sagittal height Sag5 of the semi-aperture of the light passing through the object side of the third lens satisfy: -0.1 < Sag5 / d5 < 0; the semi-aperture d7 of the light passing through the object side of the fourth lens and the sagittal height Sag7 of the semi-aperture of the light passing through the object side of the fourth lens satisfy: -0.2 < Sag7 / d7 < 0. Satisfying the above range and reasonably defining the semi-aperture of the light passing through the object side of the third lens and the corresponding sagittal height of the semi-aperture, the semi-aperture of the light passing through the object side of the fourth lens and the corresponding sagittal height of the semi-aperture can effectively control the light trend in the marginal field of view and improve the imaging quality in the marginal field of view. Preferably, -0.04 < Sag5 / d5 < -0.01; -0.19 < Sag7 / d7 < -0.02.

[0081] In some embodiments, the semi-aperture d1 of the light passing through the object side of the first lens, the true image height IH corresponding to the maximum field angle of the optical lens, and the maximum field angle FOV of the optical lens satisfy: 0.9 < d1 / (IH / 2) / tan(FOV / 2) < 1.3. Satisfying the above range and reasonably defining the front aperture diameter, true image height, and maximum field angle of the optical lens can reasonably arrange the overall geometric shape of the optical lens and improve its structural stability. Preferably, 0.9 < d1 / (IH / 2) / tan(FOV / 2) < 1.2. [[ID=1...]]

[0082] In some embodiments, the total optical length TTL of the optical lens and the sum ∑CT of the central thicknesses of the first lens, the second lens, the third lens, the fourth lens, the fifth lens, and the sixth lens satisfy: 1.5 < TTL / ∑CT < 2.6. Meeting the above range can achieve high pixel characteristics and improve the imaging quality of the optical lens. Preferably, 1.7 < TTL / ∑CT < 2.4.

[0083] In some embodiments, the fourth lens and the fifth lens form a cemented lens group, and the image side of the fourth lens and the object side of the fifth lens are cemented surfaces. Meeting the above range can effectively correct the chromatic aberration of the optical lens, reduce the eccentricity sensitivity of the optical lens, balance the aberration of the optical lens, and improve the imaging quality of the optical lens; it can also reduce the assembly sensitivity of the optical lens, thereby reducing the processing difficulty of the optical lens and improving the assembly yield of the optical lens.

[0084] In some embodiments, the fourth lens and the fifth lens form a cemented lens group with positive optical power, and the image side of the fourth lens and the object side of the fifth lens are cemented surfaces. The combined focal length f45 of the fourth lens and the fifth lens and the effective focal length f of the optical lens satisfy: 16.6 < f45 / f < 17.9.

[0085] In some embodiments, the fourth lens and the fifth lens form a cemented lens group with negative optical power, and the image side of the fourth lens and the object side of the fifth lens are cemented surfaces. The combined focal length f45 of the fourth lens and the fifth lens and the effective focal length f of the optical lens satisfy: -10.0 < f45 / f < -9.8.

[0086] In some embodiments, the optical lens satisfies the following conditional expressions: 5.3 mm < f < 6.7 mm; 65° < FOV < 75°; 3.1 mm < EPD < 3.6 mm; 20 mm < TTL < 28 mm; 1.6 < FNO < 1.9; 5.9 mm < IH < 7.1 mm; 22° < CRA < 35°; BFL > 1.9 mm. In the above conditional expressions, f represents the effective focal length of the optical lens, FOV represents the maximum field of view angle of the optical lens, EPD represents the entrance pupil diameter of the optical lens, TTL represents the total optical length of the optical lens, FNO represents the aperture value of the optical lens, IH represents the true image height corresponding to the maximum field of view angle of the optical lens, CRA represents the chief ray incident angle at the maximum image height of the optical lens, and BFL represents the back focal length of the optical lens. Preferably, 5.8 mm < f < 6.1 mm; 67° < FOV < 72°; 3.3 mm < EPD < 3.5 mm; 21.9 mm < TTL < 26.1 mm; 1.7 < FNO < 1.9; 6.5 mm < IH < 6.6 mm; 25.4° < CRA < 33.7°; 1.9 mm < BFL < 2.1 mm. Meeting the above ranges, the optical lens has at least one or more advantages such as a large target surface, low cost, and high resolution.

[0087] In some embodiments, the first lens, the second lens, the third lens, the fourth lens, the fifth lens, and the sixth lens can be spherical lenses or aspherical lenses. Compared with the spherical structure, the aspherical structure can effectively reduce the aberration of the optical system, thereby reducing the number of lenses and the size of the lenses, and better achieving the miniaturization of the lens. More specifically, the first lens, the third lens, the fourth lens, and the fifth lens of the present invention are spherical lenses, and the second lens and the sixth lens are aspherical lenses.

[0088] In each embodiment of the present invention, when the lens is an aspherical lens, the shapes of the aspherical surfaces of the optical lens satisfy the following equations:

[0089]

[0090] where z is the distance between the surface and the vertex of the surface in the optical axis direction, h is the distance from the optical axis to the surface, c is the curvature of the vertex of the surface, K is the conic coefficient, and B, C, D, E, and F are the fourth-order, sixth-order, eighth-order, tenth-order, and twelfth-order surface coefficients, respectively.

[0091] The present invention will be further described below with reference to several embodiments. In each embodiment, the thickness, radius of curvature, and material selection of each lens in the optical lens are different; for specific differences, please refer to the parameter tables of each embodiment. The following embodiments are merely preferred embodiments of the present invention, but the embodiments of the present invention are not limited to the following embodiments. Any changes, substitutions, combinations, or simplifications made without departing from the innovative points of the present invention should be considered equivalent substitutions and are included within the protection scope of the present invention.

[0092] Example 1

[0093] Please see Figure 1 The diagram shows a schematic of the structure of the optical lens 100 provided in Embodiment 1 of the present invention. The optical lens 100 includes, along the optical axis from the object side to the imaging surface, the following components in sequence: a first lens L1, a second lens L2, an aperture ST, a third lens L3, a fourth lens L4, a fifth lens L5, a sixth lens L6, a filter G1, and a protective glass G2.

[0094] Among them, the first lens L1 has negative optical power, its object side S1 is concave, and its image side S2 is convex.

[0095] The second lens L2 has positive optical power, and its object side surface S3 and image side surface S4 are both convex surfaces.

[0096] The third lens L3 has positive optical power, its object side S5 is concave, and its image side S6 is convex.

[0097] The fourth lens L4 has negative optical power, and both its object-side surface S7 and image-side surface S8 are concave.

[0098] The fifth lens L5 has positive optical power, and both its object-side surface S8 and image-side surface S9 are convex.

[0099] The fourth lens L4 and the fifth lens L5 form a cemented lens group with positive optical power, that is, the cemented surface of the image side of the fourth lens L4 and the object side of the fifth lens L5 is S8.

[0100] The sixth lens L6 has negative optical power, and both its object-side surface S10 and image-side surface S11 are concave.

[0101] The object-side surface S12 and the image-side surface S13 of the filter G1 are both planar.

[0102] The object side S14 and image side S15 of the protective glass G2 are both flat.

[0103] The imaging plane S16 is a plane.

[0104] The first lens L1, the third lens L3, the fourth lens L4, and the fifth lens L5 are glass spherical lenses, while the second lens L2 and the sixth lens L6 are glass aspherical lenses.

[0105] The relevant parameters of each lens in the optical lens 100 in Example 1 are shown in Table 1-1.

[0106] Table 1-1

[0107]

[0108]

[0109] The surface profile parameters of the aspherical lens of the optical lens 100 in Example 1 are shown in Table 1-2.

[0110] Table 1-2

[0111] Face number K B C D E F S3 4.57E+00 -1.72E-03 -5.64E-05 -7.14E-06 3.47E-07 -3.00E-08 S4 2.40E+01 -3.88E-04 -8.34E-05 1.38E-05 -2.45E-06 1.67E-07 S10 3.26E+01 -2.46E-02 3.09E-03 -3.04E-04 5.40E-06 1.00E-06 S11 4.12E+00 -2.25E-02 3.13E-03 -3.54E-04 2.09E-05 -4.73E-07

[0112] In this embodiment, the field curvature curve, F-θ distortion curve, axial aberration curve, transverse chromatic aberration curve, and MTF (modulation transfer function) curve of the optical lens 100 are respectively as follows: Figure 2 , Figure 3 , Figure 4 , Figure 5 and Figure 6 As shown.

[0113] Figure 2 The field curvature curve of Example 1 is shown, which represents the degree of curvature of light of different wavelengths in the meridional and sagittal image planes. The horizontal axis represents the offset (unit: mm), and the vertical axis represents the half field of view (unit: °). As can be seen from the figure, the field curvature of the meridional and sagittal image planes is controlled within -0.02 mm to 0.02 mm, indicating that the optical lens can effectively correct field curvature.

[0114] Figure 3 The F-θ distortion curve of Example 1 is shown, which represents the F-θ distortion of light of different wavelengths at different image heights on the imaging plane. The horizontal axis represents the F-θ distortion value (unit: %), and the vertical axis represents the half field of view (unit: °). As can be seen from the figure, the F-θ distortion of the optical lens is controlled within -12% to 0, and the image compression in the edge angle region is relatively smooth, effectively improving the sharpness of the unfolded image.

[0115] Figure 4The axial aberration curve of Example 1 is shown, which represents the aberration of each wavelength on the optical axis at the imaging plane. The horizontal axis represents the axial aberration value (unit: mm), and the vertical axis represents the normalized pupil radius. As can be seen from the figure, the axial aberration offset is controlled within -0.01 mm to 0.02 mm, indicating that the optical lens can correct axial aberration well.

[0116] Figure 5 The diagram shows the transverse chromatic aberration curves for Example 1, representing the chromatic aberration of each wavelength relative to the center wavelength (0.55 μm) at different image heights on the imaging plane. The horizontal axis represents the transverse chromatic aberration value of each wavelength relative to the center wavelength (unit: μm), and the vertical axis represents the normalized field of view. As can be seen from the diagram, the transverse chromatic aberration of the longest and shortest wavelengths is controlled within -2.5 μm to 3.5 μm, indicating that the optical lens can excellently correct chromatic aberration at the edge of the field of view and the secondary spectrum of the entire image plane.

[0117] Figure 6 The MTF (Modulation Transfer Function) curve of Example 1 is shown, which represents the lens imaging modulation at different spatial frequencies in each field of view. The horizontal axis represents the spatial frequency (unit: lp / mm), and the vertical axis represents the MTF value. As can be seen from the figure, the MTF value of this example is above 0.4 throughout the entire field of view. Within the range of 0–160 lp / mm, the MTF curve decreases smoothly and evenly from the center to the edge of the field of view, exhibiting good image quality and good detail resolution.

[0118] Example 2

[0119] Please see Figure 7 The figure shown is a schematic diagram of the structure of the optical lens 200 provided in Embodiment 2 of the present invention. The main difference between this embodiment and Embodiment 1 is that the optical parameters such as the radius of curvature and lens thickness of each lens surface are different.

[0120] The relevant parameters of each lens in the optical lens 200 in Example 2 are shown in Table 2-1.

[0121] Table 2-1

[0122]

[0123] The surface profile parameters of the aspherical lens of the optical lens 200 in Example 2 are shown in Table 2-2.

[0124] Table 2-2

[0125] Face number K B C D E F S3 -5.45E+00 -8.69E-04 6.88E-06 -8.87E-06 8.95E-07 -1.73E-08 S4 -1.32E+00 -1.47E-04 -1.17E-05 2.56E-06 -1.32E-08 2.53E-08 S10 -9.06E-01 -1.12E-02 2.67E-03 -3.18E-04 1.80E-05 -3.35E-07 S11 4.97E+01 -1.02E-02 2.08E-03 -1.92E-04 8.04E-06 -5.30E-08

[0126] In this embodiment, the field curvature curve, F-θ distortion curve, axial aberration curve, transverse chromatic aberration curve, and MTF (modulation transfer function) curve of the optical lens 200 are respectively as follows: Figure 8 , Figure 9 , Figure 10 , Figure 11 and Figure 12 As shown. From Figure 8 As can be seen, the field curvature of the meridional and sagittal image planes is controlled within -0.03mm to 0.03mm, indicating that the optical lens can effectively correct field curvature. From Figure 9 As can be seen, the F-θ distortion of the optical lens is controlled within -10% to 0, and the image compression in the edge angle region is relatively smooth, effectively improving the sharpness of the unfolded image. From Figure 10 As can be seen, the axial aberration offset in this embodiment is controlled within -0.02mm to 0.03mm, indicating that the optical lens can effectively correct axial aberration. From Figure 11 As can be seen, the transverse chromatic aberration of the longest and shortest wavelengths is controlled within -3μm to 3.5μm, indicating that this optical lens can excellently correct chromatic aberration at the edges of the field of view and the second-order spectrum of the entire image plane. From Figure 12 As can be seen, the MTF value of this embodiment is above 0.35 throughout the entire field of view. Within the range of 0 to 160 lp / mm, the MTF curve decreases smoothly and evenly from the center to the edge of the field of view, indicating that the optical lens has good imaging quality and good detail resolution.

[0127] Example 3

[0128] Please see Figure 13 The figure shows a schematic diagram of the structure of the optical lens 300 provided in Embodiment 3 of the present invention. The main differences between this embodiment and Embodiment 1 are: the optical parameters such as the radius of curvature and lens thickness of each lens surface are different; the object side surface S3 of the second lens L2 is concave; the image side surface S11 of the sixth lens L6 is convex; and the fourth lens L4 and the fifth lens L5 form a cemented lens group with negative optical power.

[0129] The relevant parameters of each lens in the optical lens 300 in Example 3 are shown in Table 3-1.

[0130] Table 3-1

[0131]

[0132]

[0133] The surface profile parameters of the aspherical lens of the optical lens 300 in Example 3 are shown in Table 3-2.

[0134] Table 3-2

[0135] Face number K B C D E F S3 5.00E+01 -2.14E-03 -8.36E-07 -9.07E-06 1.42E-06 -4.05E-08 S4 -1.50E+00 -4.89E-04 4.65E-06 3.53E-06 -1.64E-07 2.21E-08 S10 -1.21E+00 5.52E-02 -8.98E-03 8.40E-04 -4.14E-05 7.74E-07 S11 -8.66E-01 5.67E-02 -5.85E-03 3.14E-04 3.31E-07 -4.99E-07

[0136] In this embodiment, the field curvature curve, F-θ distortion curve, axial aberration curve, transverse chromatic aberration curve, and MTF (modulation transfer function) curve of the optical lens 300 are respectively as follows: Figure 14 , Figure 15 , Figure 16 , Figure 17 and Figure 18 As shown. From Figure 14 As can be seen, the field curvature of the meridional and sagittal image planes is controlled within -0.03mm to 0.02mm, indicating that the optical lens can effectively correct field curvature. From Figure 15 As can be seen, the F-θ distortion of the optical lens is controlled within -10% to 0, and the image compression in the edge angle region is relatively smooth, effectively improving the sharpness of the unfolded image. From Figure 16 As can be seen, the axial aberration offset in this embodiment is controlled within -0.01mm to 0.02mm, indicating that the optical lens can effectively correct axial aberration. From Figure 17 As can be seen, the transverse chromatic aberration of the longest and shortest wavelengths is controlled within -2.5μm to 3.5μm, indicating that this optical lens can excellently correct chromatic aberration at the edges of the field of view and the second-order spectrum of the entire image plane. From Figure 18 As can be seen, the MTF value of this embodiment is above 0.35 throughout the entire field of view. Within the range of 0 to 160 lp / mm, the MTF curve decreases smoothly and evenly from the center to the edge of the field of view, indicating that the optical lens has good imaging quality and good detail resolution.

[0137] Please refer to Table 4 for the optical characteristics corresponding to each of the above embodiments, including the effective focal length f, total optical length TTL, aperture value Fno, true image height IH corresponding to the maximum field of view, maximum field of view FOV, and the values ​​corresponding to each conditional expression in each embodiment.

[0138] Table 4

[0139]

[0140]

[0141]

[0142] In summary, the optical lens provided by the present invention uses six lenses with specific optical power. Through specific surface shape matching and reasonable optical power distribution, it can improve the imaging quality of the optical lens, reduce aberrations, and enhance the imaging quality of the optical lens, giving the lens one or more advantages such as low cost, high resolution, and high imaging quality.

[0143] In the description of this specification, references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0144] The embodiments described above are merely illustrative of several implementations of the present invention, and while the descriptions are specific and detailed, they should not be construed as limiting the scope of the present invention. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these modifications and improvements all fall within the scope of protection of the present invention. Therefore, the scope of protection of this patent should be determined by the appended claims.

Claims

1. An optical lens comprising six lenses, characterized in that, It sequentially includes from the object side to the imaging plane along the optical axis: A first lens with a negative optical power, whose object side is concave and whose image side is convex; A second lens with a positive optical power, whose image side is convex; A third lens with a positive optical power, whose object side is concave and whose image side is convex; A fourth lens with a negative optical power, whose object side and image side are both concave; A fifth lens with a positive optical power, whose object side and image side are both convex; A sixth lens with a negative optical power, whose object side is concave; Wherein, the radius of curvature R2 of the image side of the first lens and the effective focal length f of the optical lens satisfy: -8.79 ≤ R2 / f < -3; The true image height IH corresponding to the maximum field angle of the optical lens and the entrance pupil diameter EPD of the optical lens satisfy: 1.7 < IH / EPD < 2.

1.

2. The optical lens according to claim 1, characterized in that, The focal length f1 of the first lens and the effective focal length f of the optical lens satisfy: -5.9 < f1 / f < -2.

9.

3. The optical lens according to claim 1, characterized in that, The focal length f6 of the sixth lens and the effective focal length f of the optical lens satisfy: -4.5 < f6 / f < -0.

8.

4. The optical lens according to claim 1, characterized in that, The combined focal length f12 of the first lens and the second lens and the effective focal length f of the optical lens satisfy: 0.9 < f12 / f < 1.

6.

5. The optical lens according to claim 1, characterized in that, The radius of curvature R2 of the image side of the first lens and the focal length f1 of the first lens satisfy: 1.5 < R2 / f1 < 2.

9.

6. The optical lens according to claim 1, characterized in that, The radius of curvature R4 of the image side of the second lens and the focal length f2 of the second lens satisfy: -3.9 < R4 / f2 < -0.3; the radius of curvature R11 of the object side of the sixth lens and the focal length f6 of the sixth lens satisfy: 0 < R11 / f6 < 2.

5.

7. The optical lens according to claim 1, characterized in that, The radius of curvature R5 of the object side of the third lens and the focal length f3 of the third lens satisfy: -5.2 < R5 / f3 < -1.9; the radius of curvature R7 of the object side of the fourth lens and the focal length f4 of the fourth lens satisfy: 1.9 < R7 / f4 < 13.

4.

8. The optical lens according to claim 1, characterized in that, The true image height IH corresponding to the maximum field angle of the optical lens, the effective focal length f of the optical lens, and the radian θ of the maximum half field angle of the optical lens satisfy: 0.88 < (IH / 2) / (f×θ) < 1.

00.

9. The optical lens according to claim 1, characterized in that, The maximum field angle FOV of the optical lens, the effective focal length f of the optical lens, and the true image height IH corresponding to the maximum field angle of the optical lens satisfy: 60° < FOV×f / IH < 70°.

10. The optical lens according to claim 1, characterized in that, The clear aperture semi-diameter d2 of the image side of the first lens and the sagittal height Sag2 of the clear aperture of the image side of the first lens satisfy: -0.1 < Sag2 / d2 < 0; the center-to-center distance CT12 of the first lens and the second lens on the optical axis and the center-to-center distance CT23 of the second lens and the third lens on the optical axis satisfy: 15 < CT12 / CT23 ≤ 39.1; The radius of curvature R2 of the image side of the first lens and the effective focal length f of the optical lens satisfy: -8.79 ≤ R2 / f ≤ -8.39; The true image height IH corresponding to the maximum field angle of the optical lens and the entrance pupil diameter EPD of the optical lens satisfy: 1.8 < IH / EPD < 2.0.

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