Optical lens

Abstract

This invention provides an optical lens comprising eight lenses of optical power, arranged sequentially along the optical axis from the object side to the image plane: a first lens with negative optical power, having a convex object side and a concave image side; a second lens with negative optical power, having a convex object side and a concave image side; a third lens with negative optical power, having a concave object side and a convex image side near the optical axis; a fourth lens with positive optical power, having a convex object side and a convex image side; a fifth lens with positive optical power, having a convex object side and a concave image side; a sixth lens with negative optical power, having a convex object side and a concave image side; a seventh lens with negative optical power, having a convex object side near the optical axis and a concave image side; and an eighth lens with positive optical power, having a convex object side. The optical lens provided by this invention can improve the image quality of an optical lens, reduce aberrations, and enhance the overall image quality.

Description

Technical Field

[0001] The present invention relates to the technical field of imaging lenses, in particular to an optical lens. Background Art

[0002] In the field of modern motion image capture, high-performance portable optical systems are the core demand. Most motion camera lenses currently on the market adopt a large-aperture, ultra-wide-angle design to adapt to high-speed motion scenes and extreme environment shooting. However, these traditional optical structures generally have the problems of degraded imaging quality in low-light environments and insufficient dynamic range. At the same time, the increase of the field of view of the lens leads to difficulty in correcting system aberrations and the degradation of imaging quality; in addition, the existing lenses have a small imaging target surface, which is difficult to meet market demands. Summary of the Invention

[0003] In view of the above problems, an object of the present invention is to provide an optical lens, which has the advantage of excellent imaging quality.

[0004] To achieve the above object, the technical solution adopted by the present invention is: An optical lens has eight lenses with optical power, and sequentially includes from the object side to the imaging surface along the optical axis: A first lens with negative optical power, whose object side surface is convex and whose image side surface is concave; A second lens with negative optical power, whose object side surface is convex and whose image side surface is concave; A third lens with negative optical power, whose object side surface is concave and whose image side surface is convex near the optical axis; A fourth lens with positive optical power, whose object side surface is convex and whose image side surface is convex; A fifth lens with positive optical power, whose object side surface is convex and whose image side surface is concave; A sixth lens with negative optical power, whose object side surface is convex and whose image side surface is concave; A seventh lens with negative optical power, whose object side surface is convex near the optical axis and whose image side surface is concave; An eighth lens with positive optical power, whose object side surface is convex and whose image side surface is convex; Wherein, the real image height IH corresponding to the maximum field of view of the optical lens and the effective focal length f of the optical lens satisfy: 2.7<IH / f<3.9; the combined focal length f5678 of the fifth lens, the sixth lens, the seventh lens and the eighth lens and the effective focal length f of the optical lens satisfy: 0.7<f5678 / f<1.7.

[0005] Further preferably, the optical lens satisfies one or several of the following conditional expressions: the total optical length TTL of the optical lens and the effective focal length f of the optical lens satisfy: 5.7<TTL / f<8.2; the total optical length TTL of the optical lens and the real image height IH corresponding to the maximum field of view of the optical lens satisfy: 1.9<TTL / IH<2.4.

[0006] Further preferably, the optical lens satisfies one or several of the following conditional expressions: the maximum field of view FOV of the optical lens and the aperture value Fno of the optical lens satisfy: 48°<FOV / Fno<60°; the real image height IH corresponding to the maximum field of view of the optical lens and the entrance pupil diameter EPD of the optical lens satisfy: 7.5<IH / EPD<11.

[0007] Further preferably, the optical lens satisfies one or several of the following conditional expressions: the effective focal length f of the optical lens, the real image height IH corresponding to the maximum field of view of the optical lens and the maximum field of view FOV of the optical lens satisfy: 40°<f×FOV / IH<58°; the clear half-aperture d1 of the object side of the first lens, the real image height IH corresponding to the maximum field of view of the optical lens and the maximum field of view FOV of the optical lens satisfy: 0.18<d1 / (IH / 2) / tan(FOV / 2)<0.34; the real image height IH corresponding to the maximum field of view of the optical lens, the effective focal length f of the optical lens and the radian value θ of the maximum half field of view of the optical lens satisfy: 1.05<(IH / 2) / (f×θ)<1.3.

[0008] Further preferably, the optical lens satisfies one or several of the following conditional expressions: the focal length f1 of the first lens and the effective focal length f of the optical lens satisfy: -35<f1 / f<-5.7; the focal length f2 of the second lens and the effective focal length f of the optical lens satisfy: -5.3<f2 / f<-1.4; the focal length f3 of the third lens and the effective focal length f of the optical lens satisfy: -250<f3 / f<-4.8; the focal length f4 of the fourth lens and the effective focal length f of the optical lens satisfy: 1.3<f4 / f<2.4; the focal length f7 of the seventh lens and the effective focal length f of the optical lens satisfy: -5.7<f7 / f<-0.9; the focal length f8 of the eighth lens and the effective focal length f of the optical lens satisfy: 0.7<f8 / f<1.4.

[0009] Further preferably, the optical lens satisfies one or more of the following conditional expressions: the focal length f5 of the fifth lens and the effective focal length f of the optical lens satisfy: 1.2<f5 / f<1.8; the radius of curvature R9 of the object-side surface of the fifth lens and the effective focal length f of the optical lens satisfy: 0.7<R9 / f<1; the radius of curvature R10 of the image-side surface of the fifth lens and the effective focal length f of the optical lens satisfy: 20<R10 / f<26.

[0010] Further preferably, the optical lens satisfies one or more of the following conditional expressions: the focal length f6 of the sixth lens and the effective focal length f of the optical lens satisfy: -1.4<f6 / f<-1; the radius of curvature R11 of the object-side surface of the sixth lens and the effective focal length f of the optical lens satisfy: 20<R11 / f<26; the radius of curvature R12 of the image-side surface of the sixth lens and the effective focal length f of the optical lens satisfy: 0.8<R12 / f<0.9.

[0011] Further preferably, the optical lens satisfies one or more of the following conditional expressions: the combined focal length f1234 of the first lens, the second lens, the third lens and the fourth lens and the combined focal length f5678 of the fifth lens, the sixth lens, the seventh lens and the eighth lens satisfy: 1<f1234 / f5678<2.5; the focal length f5 of the fifth lens and the combined focal length f5678 of the fifth lens, the sixth lens, the seventh lens and the eighth lens satisfy: 0.8<f5 / f5678<2.1; the focal length f6 of the sixth lens and the combined focal length f5678 of the fifth lens, the sixth lens, the seventh lens and the eighth lens satisfy: -1.7<f6 / f5678<-0.7.

[0012] Further preferably, the optical lens satisfies one or more of the following conditional expressions: the focal length f4 of the fourth lens and the focal length f5 of the fifth lens satisfy: 1<f4 / f5<1.6; the focal length f5 of the fifth lens and the focal length f6 of the sixth lens satisfy: -1.5<f5 / f6<-1; the focal length f6 of the sixth lens and the focal length f7 of the seventh lens satisfy: 0.2<f6 / f7<1.3.

[0013] Further preferably, the optical lens satisfies one or more of the following conditional expressions: the real image height IH corresponding to the maximum field angle of the optical lens and the effective focal length f of the optical lens satisfy: 2.95<IH / f<3.56; the combined focal length f5678 of the fifth lens, the sixth lens, the seventh lens and the eighth lens and the effective focal length f of the optical lens satisfy: 0.77<f5678 / f<1.52.

[0014] The optical lens provided by this invention uses eight 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 miniaturization, large field of view, large image plane, high pixel count, and high imaging quality. Attached Figure Description

[0015] 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: Figure 1 This is a schematic diagram of the optical lens structure in Embodiment 1 of the present invention.

[0016] Figure 2 This is an F-Theta distortion curve of the optical lens in Embodiment 1 of the present invention.

[0017] Figure 3 This is an axial aberration curve of the optical lens in Embodiment 1 of the present invention.

[0018] Figure 4 This is a chromatic aberration curve of the optical lens in Embodiment 1 of the present invention.

[0019] Figure 5 This is an MTF curve of the optical lens in Embodiment 1 of the present invention.

[0020] Figure 6 This is a schematic diagram of the optical lens structure in Embodiment 2 of the present invention.

[0021] Figure 7 This is the F-Theta distortion curve of the optical lens in Embodiment 2 of the present invention.

[0022] Figure 8 This is an axial aberration curve of the optical lens in Embodiment 2 of the present invention.

[0023] Figure 9 This is a chromatic aberration curve of the optical lens in Embodiment 2 of the present invention.

[0024] Figure 10 This is the MTF curve of the optical lens in Embodiment 2 of the present invention.

[0025] Figure 11 This is a field curvature curve diagram of the optical lens in Embodiment 3 of the present invention.

[0026] Figure 12 This is the F-Theta distortion curve of the optical lens in Embodiment 3 of the present invention.

[0027] Figure 13This is an axial aberration curve of the optical lens in Embodiment 3 of the present invention.

[0028] Figure 14 This is a chromatic aberration curve of the optical lens in Embodiment 3 of the present invention.

[0029] Figure 15 This is an MTF curve of the optical lens in Embodiment 3 of the present invention.

[0030] The following detailed description, in conjunction with the accompanying drawings, will further illustrate the present invention. Detailed Implementation

[0031] 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.

[0032] 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.

[0033] 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.

[0034] In this article, the paraxial region refers to the region near the optical axis. If the lens surface is convex and the location of the convexity is not defined, it means that the lens surface is convex at least in the paraxial region; if the lens surface is concave and the location of the concaveness is not defined, it means that the lens surface is concave at least in the paraxial region. 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.

[0035] 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.

[0036] 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.

[0037] 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.

[0038] The optical lens of this embodiment of the invention has eight lenses with optical power, arranged sequentially along the optical axis from the object side to the imaging plane as follows: first lens, second lens, third lens, fourth lens, fifth lens, sixth lens, seventh lens, and eighth lens.

[0039] In some embodiments, the first lens may have negative optical power, with a convex object-side surface and a concave image-side surface. The second lens may have negative optical power, with a convex object-side surface and a concave image-side surface. The third lens may have negative optical power, with a concave object-side surface and a convex image-side surface near the optical axis. The fourth lens may have positive optical power, with both its object-side and image-side surfaces being convex. The fifth lens may have positive optical power, with a convex object-side surface and a concave image-side surface. The sixth lens may have negative optical power, with a convex object-side surface and a concave image-side surface. The seventh lens may have negative optical power, with a convex object-side surface near the optical axis and a concave image-side surface. The eighth lens may have positive optical power, with both its object-side and image-side surfaces being convex.

[0040] In some embodiments, the optical lens may also include an aperture stop, which may be located between the fourth and fifth lenses. It is understood that the aperture stop is used to limit the amount of light entering the lens, thereby altering the brightness of the image.

[0041] In some embodiments, the optical lens may further include an optical filter, which is disposed between the eighth lens and the imaging surface. The optical filter is configured to filter out interfering light, preventing the interfering light from reaching the imaging surface of the optical lens and affecting normal imaging.

[0042] In some embodiments, the fifth lens and the sixth lens may be cemented to form a cemented lens group with optical power, which can effectively correct chromatic aberration of the optical lens, reduce the eccentricity sensitivity of the optical lens, balance the aberrations 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 lowering the processing difficulty of the optical lens and increasing the assembly yield of the optical lens.

[0043] In some embodiments, the real image height IH corresponding to the maximum field angle of the optical lens and the effective focal length f of the optical lens satisfy: 2.7<IH / f<3.9. When the above range is satisfied, by reasonably controlling the ratio of the image height to the focal length of the lens, the characteristics of ultra-wide angle and large image surface are realized. More specifically, 2.95<IH / f<3.56.

[0044] In some embodiments, the combined focal length f5678 of the fifth lens, the sixth lens, the seventh lens and the eighth lens and the effective focal length f of the optical lens satisfy: 0.7<f5678 / f<1.7; the combined focal length f1234 of the first lens, the second lens, the third lens and the fourth lens and the combined focal length f5678 of the fifth lens, the sixth lens, the seventh lens and the eighth lens satisfy: 1<f1234 / f5678<2.5; the combined focal length f1234 of the first lens, the second lens, the third lens and the fourth lens and the effective focal length f of the optical lens satisfy: 1.5<f1234 / f<2.1. When the above ranges are satisfied, by reasonably setting the focal lengths of the lens groups before and after the aperture stop, it is beneficial to balance various aberrations generated by the lens group in front of the aperture stop and improve the overall imaging quality. More specifically, 0.77<f5678 / f<1.52; 1.1<f1234 / f5678<2.26; 1.66<f1234 / f<1.86.

[0045] In some embodiments, the total optical length TTL of the optical lens and the effective focal length f of the optical lens satisfy: 5.7<TTL / f<8.2. When the above range is satisfied, the length of the lens can be effectively limited, which is beneficial to realize the miniaturization of the optical lens. More specifically, 6.27<TTL / f<7.59.

[0046] In some embodiments, the total optical length TTL of the optical lens and the real image height IH corresponding to the maximum field of view angle of the optical lens satisfy: 1.9<TTL / IH<2.4. Meeting the above range ensures that the lens has a larger image plane under the condition of the same total length, can match an imaging chip of a larger size to achieve high-definition imaging, and better realize the balance between the small total length and the large image plane of the lens. More specifically, 2.07<TTL / IH<2.15.

[0047] In some embodiments, the maximum field of view angle FOV of the optical lens and the aperture value Fno of the optical lens satisfy: 48°<FOV / Fno<60°. Meeting the above conditions is beneficial to expanding the field of view angle of the lens and increasing the aperture of the lens, so as to realize the characteristics of wide angle and large aperture of the lens. The wide-angle characteristic can meet the demand for large-range detection. More specifically, 51.94°<FOV / Fno<56.8°.

[0048] In some embodiments, the real image height IH corresponding to the maximum field of view angle of the optical lens and the entrance pupil diameter EPD of the optical lens satisfy: 7.5<IH / EPD<11. Meeting the above range can increase the width of the light beam entering the optical lens, so that the brightness of the optical lens at the image plane is improved and vignetting is avoided. More specifically, 8.28<IH / EPD<9.94.

[0049] In some embodiments, the effective focal length f of the optical lens, the real image height IH corresponding to the maximum field of view angle of the optical lens, and the maximum field of view angle FOV of the optical lens satisfy: 40°<f×FOV / IH<58°. Meeting the above conditional expressions, by reasonably limiting the relationship among the focal length, the field of view angle and the image height of the optical lens, is conducive to realizing the balance between the field of view angle of the optical lens and large-target-surface imaging, and better meets the use demand of the optical lens for high-image-quality shooting. More specifically, 44.81°<f×FOV / IH<52.59°.

[0050] In some embodiments, the clear aperture half-diameter d1 of the object-side surface of the first lens, the real image height IH corresponding to the maximum field of view angle of the optical lens, and the maximum field of view angle FOV of the optical lens satisfy: 0.18<d1 / (IH / 2) / tan(FOV / 2)<0.34. Meeting the above range can ensure the balance among the size of the optical lens, the field of view angle and the image plane.

[0051] In some embodiments, the real image height IH corresponding to the maximum field of view angle of the optical lens, the effective focal length f of the optical lens, and the radian value θ of the maximum half field of view angle of the optical lens satisfy: 1.05<(IH / 2) / (f×θ)<1.3. Meeting the above range can make the lens have a small distortion value and provide a high-definition imaging effect. More specifically, 1.08<(IH / 2) / (f×θ)<1.29.

[0052] In some embodiments, the focal length f1 of the first lens and the effective focal length f of the optical lens satisfy: -35<f1 / f<-5.7. When the above range is satisfied, the first lens has an appropriate negative focal length, which is beneficial to expanding the field of view of the optical lens. More specifically, -31.27<f1 / f<-6.36.

[0053] In some embodiments, the focal length f2 of the second lens and the effective focal length f of the optical lens satisfy: -5.3<f2 / f<-1.4. When the above range is satisfied, the second lens also adopts a negative lens, which can further diverge light rays and improve the field of view of the imaging system. More specifically, -4.87<f2 / f<-1.59.

[0054] In some embodiments, the focal length f3 of the third lens and the effective focal length f of the optical lens satisfy: -250<f3 / f<-4.8. When the above range is satisfied, the third lens has an appropriate optical power, which can control the direction of the optical path, provide a more reasonable incident angle of light for subsequent lenses, improve the uniformity of relative illumination, and enhance the imaging quality. More specifically, -227.32<f3 / f<-5.33.

[0055] In some embodiments, the focal length f4 of the fourth lens and the effective focal length f of the optical lens satisfy: 1.3<f4 / f<2.4. When the above range is satisfied, the fourth lens has an appropriate optical power to converge the light rays incident from the front end, which is beneficial to correcting the aberration caused by the front lens group and the distortion of the marginal field of view, so that the lens has low distortion and can provide a high-definition imaging effect. More specifically, 1.5<f4 / f<2.17.

[0056] In some embodiments, the focal length f7 of the seventh lens and the effective focal length f of the optical lens satisfy: -5.7<f7 / f<-0.9. When the above range is satisfied, it is beneficial to the smooth transition of light rays, and at the same time corrects the field curvature and distortion of the optical lens, so as to improve the imaging quality of the optical lens. More specifically, -5.2<f7 / f<-0.98.

[0057] In some embodiments, the focal length f8 of the eighth lens and the effective focal length f of the optical lens satisfy: 0.7<f8 / f<1.4. When the above range is satisfied, it is beneficial to the smooth transition of light rays, facilitates the correction of astigmatism and field curvature, improves the imaging quality of the optical lens, and ensures the stability of the optical system. More specifically, 0.79<f8 / f<1.28.

[0058] In some embodiments, the focal length f5 of the fifth lens and the effective focal length f of the optical lens satisfy: 1.2<f5 / f<1.8; the radius of curvature R9 of the object-side surface of the fifth lens and the effective focal length f of the optical lens satisfy: 0.7<R9 / f<1; the radius of curvature R10 of the image-side surface of the fifth lens and the effective focal length f of the optical lens satisfy: 20<R10 / f<26. Meeting the above ranges is conducive to the smooth transition of light rays, facilitates the correction of astigmatism and field curvature, improves the imaging quality of the optical lens, and ensures the stability of the optical system. More specifically, 1.36<f5 / f<1.51; 0.78<R9 / f<0.87; 22.14<R10 / f<23.48.

[0059] In some embodiments, the focal length f6 of the sixth lens and the effective focal length f of the optical lens satisfy: -1.4<f6 / f<-1; the radius of curvature R11 of the object-side surface of the sixth lens and the effective focal length f of the optical lens satisfy: 20<R11 / f<26; the radius of curvature R12 of the image-side surface of the sixth lens and the effective focal length f of the optical lens satisfy: 0.8<R12 / f<0.9. Meeting the above ranges enables sufficient correction of various aberrations of the optical lens, which can improve the resolution and achieve high definition. More specifically, -1.25<f6 / f<-1.15; 22.14<R11 / f<23.48; 0.84<R12 / f<0.87.

[0060] In some embodiments, the focal length f5 of the fifth lens and the combined focal length f5678 of the fifth lens, the sixth lens, the seventh lens and the eighth lens satisfy: 0.8<f5 / f5678<2.1; the focal length f6 of the sixth lens and the combined focal length f5678 of the fifth lens, the sixth lens, the seventh lens and the eighth lens satisfy: -1.7<f6 / f5678<-0.7. Meeting the above ranges is conducive to the smooth transition of light rays, and simultaneously corrects the field curvature and distortion of the optical lens, so as to improve the imaging quality of the optical lens. More specifically, 0.9<f5 / f5678<1.93; -1.5<f6 / f5678<-0.81.

[0061] In some embodiments, the focal length f4 of the fourth lens and the focal length f5 of the fifth lens satisfy: 1<f4 / f5<1.6; the focal length f5 of the fifth lens and the focal length f6 of the sixth lens satisfy: -1.5<f5 / f6<-1; the focal length f6 of the sixth lens and the focal length f7 of the seventh lens satisfy: 0.2<f6 / f7<1.3. Meeting the above ranges is conducive to the smooth transition of light rays, facilitates the correction of aberrations of the optical lens, and improves the imaging quality of the optical lens. More specifically, 1.08<f4 / f5<1.45; -1.3<f5 / f6<-1.09; 0.23<f6 / f7<1.19.

[0062] In some embodiments, the distance BL on the optical axis from the image side of the eighth lens to the imaging plane and the effective focal length f of the optical lens satisfy: 0.39<BL / f<0.52. Meeting the above conditions is beneficial to achieving a short back focal length of the lens, and facilitates the miniaturization of the lens while ensuring sufficient space for the installation of optical elements.

[0063] In some embodiments, the curvature radius R5 of the object side of the third lens and the effective focal length f of the optical lens satisfy: -1.6<R5 / f<-1.1; the curvature radius R6 of the image side of the third lens and the effective focal length f of the optical lens satisfy: -2.4<R6 / f<-1.3. Meeting the above ranges, the third lens is a meniscus lens, which collects as much light with a large field of view angle as possible and allows the light to smoothly enter the rear system, increases the light throughput of the optical lens, and effectively expands the field of view range of the optical lens. More specifically, -1.42<R5 / f<-1.3; -2.2<R6 / f<-1.45.

[0064] In some embodiments, the curvature radius R9 of the object side of the fifth lens and the focal length f5 of the fifth lens satisfy: 0.5<R9 / f5<0.6; the curvature radius R10 of the image side of the fifth lens and the focal length f5 of the fifth lens satisfy: 14<R10 / f5<18. Meeting the above ranges helps converge the light in the marginal field of view and improve the relative illumination. More specifically, 0.56<R9 / f5<0.59; 15.68<R10 / f5<16.25.

[0065] In some embodiments, the curvature radius R11 of the object side of the sixth lens and the curvature radius R12 of the image side of the sixth lens satisfy: 23<R11 / R12<30. Meeting the above ranges can make the sixth lens have a suitable surface profile, which can balance various aberrations generated by the optical lens and improve the imaging quality of the optical lens. More specifically, 25.74<R11 / R12<27.53.

[0066] In some embodiments, the optical lens satisfies the following conditional expressions: 4.3mm<f<5.7mm; 1.5mm<EPD<2.1mm; 32mm<TTL<37mm; 2.6<Fno<3; 10°<CRA<16°; 2mm<BL<2.5mm; 140°<FOV<170°; 15mm<IH<17mm. In the above conditional expressions, f denotes the effective focal length of the optical lens, EPD denotes the entrance pupil diameter of the optical lens, TTL denotes the total optical length of the optical lens, Fno denotes the F-number of the optical lens, CRA denotes the chief ray incident angle at the maximum image height of the optical lens, BL denotes the distance on the optical axis from the image-side surface of the eighth lens to the imaging plane, FOV denotes the maximum field angle of the optical lens, and IH denotes the real image height corresponding to the maximum field angle of the optical lens. By satisfying the above ranges, the optical lens has at least one or more advantages such as miniaturization, large image plane, and large field angle. More specifically, 4.61mm<f<5.42mm; 1.64mm<EPD<1.94mm; 33.9mm<TTL<35.1mm; 2.79<Fno<2.81; 11.19°<CRA<15.43°; 2.17mm<BL<2.34mm; 145.44°<FOV<159.1°; 16.01mm<IH<16.39mm.

[0067] In some embodiments, the material of the lenses in the optical lens provided by the present invention can be glass or plastic. When the lens material is plastic, the production cost can be effectively reduced. In addition, when the lens material is glass, the geometric chromatic aberration of the optical system can be effectively corrected by utilizing the low dispersion characteristic of glass itself. The optical lens provided by the present invention can adopt an all-glass lens structure, which can reduce dispersion, effectively correct the chromatic aberration of the optical lens, and improve the imaging quality.

[0068] In some embodiments, the first lens, the second lens, the third lens, the fourth lens, the fifth lens, the sixth lens, the seventh lens, and the eighth lens can be spherical lenses or aspheric lenses. Compared with the spherical structure, the aspheric structure can effectively reduce the aberration of the optical system, thereby reducing the number of lenses and the size of the lenses, and better realizing the miniaturization of the lens. More specifically, the second lens, the third lens, the seventh lens, and the eighth lens of the present invention adopt aspheric lenses; the first lens, the fourth lens, the fifth lens, and the sixth lens adopt spherical lenses.

[0069] In various embodiments of the present invention, when the lenses adopt aspheric lenses, each aspheric surface shape of the optical lens satisfies the following equation: ; Where z is the distance between the surface and the vertex of the surface in the direction of the optical axis, h is the distance from the optical axis to the surface, c is the curvature of the vertex of the surface, K is the quadratic surface coefficient, and A, B, C, D, E, and F are the second, fourth, sixth, eighth, tenth, and twelfth order surface coefficients, respectively.

[0070] 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.

[0071] Example 1

[0072] Please see Figure 1 The diagram shown is a structural schematic of the optical lens 100 provided in Embodiment 1 of the present invention. The optical lens includes, in sequence along the optical axis from the object side to the imaging plane: a first lens L1, a second lens L2, a third lens L3, a fourth lens L4, an aperture ST, a fifth lens L5, a sixth lens L6, a seventh lens L7, an eighth lens L8, and a filter G1.

[0073] Among them, the first lens L1 has negative optical power, its object side S1 is convex, and its image side S2 is concave. The second lens L2 has negative optical power, its object side S3 is convex, and its image side S4 is concave. The third lens L3 has negative optical power, its object side S5 is concave, and its image side S6 is convex near the optical axis. The fourth lens L4 has positive optical power, its object side S7 is convex, and its image side S8 is convex. The fifth lens L5 has positive optical power, its object side S9 is convex, and its image side is concave. The sixth lens L6 has negative optical power, its object side is convex, and its image side S11 is concave. The fifth lens L5 and the sixth lens L6 form a cemented lens group with negative optical power, that is, the cemented surface of the image side of the fifth lens L5 and the object side of the sixth lens L6 is S10. The seventh lens L7 has negative optical power, its object side S12 is convex near the optical axis, and its image side S13 is concave. The eighth lens L8 has positive optical power, its object side S14 is convex, and its image side S15 is convex. The object-side surface S16 and the image-side surface S17 of filter G1 are both planar. The imaging plane S18 is a plane.

[0074] The first, fourth, fifth, and sixth lenses are glass spherical lenses, while the second, third, seventh, and eighth lenses are glass aspherical lenses.

[0075] The relevant parameters of each lens in the optical lens 100 in Example 1 are shown in Table 1-1.

[0076] Table 1-1

[0077] The surface profile parameters of the aspherical lens of the optical lens 100 in Example 1 are shown in Table 1-2.

[0078] Table 1-2

[0079] In this embodiment, the F-Theta distortion curve, axial aberration curve, transverse chromatic aberration curve, and MTF curve of the optical lens 100 are respectively as follows: Figure 2 , Figure 3 , Figure 4 , Figure 5 As shown.

[0080] Figure 2 The F-Theta distortion curve of Example 1 is shown, which represents the F-Theta distortion of light at different image heights on the imaging plane. The horizontal axis represents the distortion value (unit: %), and the vertical axis represents the half field of view (unit: °). As can be seen from the figure, the F-Theta distortion of the optical lens is controlled within 0~50%, indicating that the optical lens can correct distortion well.

[0081] Figure 3 The 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 -0.04 mm to 0.06 mm, indicating that the optical lens can correct axial aberration well.

[0082] Figure 4 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 -3 μm to 5 μm, indicating that the optical lens can effectively correct chromatic aberration.

[0083] Figure 5The 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 0.2 throughout the entire field of view. Within the range of 0–120 lp / mm, the MTF curve decreases smoothly and uniformly from the center to the edge of the field of view, exhibiting good image quality and good detail resolution.

[0084] Example 2

[0085] Please see Figure 6 The figure shows a schematic diagram of the structure of the optical lens 200 provided in Embodiment 2 of the present invention. The optical lens in this embodiment is roughly the same as that in Embodiment 1. The main difference is that the fifth lens L5 and the sixth lens L6 form a cemented lens group with positive optical power; the optical parameters such as the radius of curvature, aspherical coefficient, and thickness of each lens surface are different.

[0086] The relevant parameters of each lens in the optical lens 200 in Example 2 are shown in Table 2-1.

[0087] Table 2-1

[0088] The surface profile parameters of the aspherical lens of the optical lens 200 in Example 2 are shown in Table 2-2.

[0089] Table 2-2

[0090] In this embodiment, the F-Theta distortion curve, axial aberration curve, transverse chromatic aberration curve, and MTF curve of the optical lens 200 are respectively as follows: Figure 7 , Figure 8 , Figure 9 , Figure 10 As shown.

[0091] from Figure 7 As can be seen, the F-Theta distortion of the optical lens is controlled within 0~20%, indicating that the optical lens can correct distortion well.

[0092] from Figure 8 As can be seen, the axial aberration offset is controlled within -0.06mm to 0.04mm, indicating that the optical lens can effectively correct axial aberration.

[0093] from Figure 9 As can be seen, the transverse chromatic aberration of the longest and shortest wavelengths is controlled within -4μm to 3μm, indicating that the optical lens can correct chromatic aberration well.

[0094] from Figure 10 As can be seen, the MTF value of this embodiment is above 0.3 throughout the entire field of view. In the range of 0 to 120 lp / mm, the MTF curve decreases smoothly and evenly from the center to the edge of the field of view, which has good imaging quality and good detail resolution.

[0095] Example 3

[0096] Please see Figure 11 The figure shows a schematic diagram of the structure of the optical lens 300 provided in Embodiment 3 of the present invention. The optical lens of this embodiment is roughly the same as that of Embodiment 1. The main difference is that the optical parameters such as the radius of curvature, aspherical coefficient, and thickness of each lens surface are different.

[0097] The relevant parameters of each lens in the optical lens 300 in Example 3 are shown in Table 3-1.

[0098] Table 3-1

[0099] The surface profile parameters of the aspherical lens of the optical lens 300 in Example 3 are shown in Table 3-2.

[0100] Table 3-2

[0101] In this embodiment, the F-Theta distortion curve, axial aberration curve, transverse chromatic aberration curve, and MTF curve of the optical lens 300 are respectively as follows: Figure 12 , Figure 13 , Figure 14 , Figure 15 As shown.

[0102] from Figure 12 As can be seen, the F-Theta distortion of the optical lens is controlled within 0-70%, indicating that the optical lens can correct distortion well.

[0103] from Figure 13 As can be seen, the axial aberration offset is controlled within -0.04mm to 0.02mm, indicating that the optical lens can effectively correct axial aberration.

[0104] from Figure 14 As can be seen, the transverse chromatic aberration of the longest and shortest wavelengths is controlled within -3μm to 2μm, indicating that the optical lens can correct chromatic aberration well.

[0105] from Figure 15As can be seen, the MTF value of this embodiment is above 0.4 throughout the entire field of view. In the range of 0 to 120 lp / mm, the MTF curve decreases smoothly and evenly from the center to the edge of the field of view, which has good imaging quality and good detail resolution.

[0106] 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, principal ray incident angle CRA at the maximum image height, maximum field of view FOV, distance BL from the image side of the eighth lens to the imaging plane on the optical axis, and the numerical value corresponding to each conditional expression in each embodiment.

[0107] Table 4

[0108] In summary, the optical lens provided by the present invention uses eight 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 miniaturization, large field of view, large image plane, high pixel count, and high imaging quality.

[0109] 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.

[0110] 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 eight lenses having optical power, characterized in that, Along the optical axis from the object side to the image plane, the components are sequentially included: A first lens with negative optical power, wherein the object side surface thereof is convex, and the image side surface thereof is concave; A second lens with negative optical power, wherein the object side surface thereof is convex, and the image side surface thereof is concave; A third lens with negative optical power, wherein the object side surface thereof is concave, and the image side surface thereof is convex at the paraxial region; A fourth lens with positive optical power, wherein the object side surface thereof is convex, and the image side surface thereof is convex; A fifth lens with positive optical power, wherein the object side surface thereof is convex, and the image side surface thereof is concave; A sixth lens with negative optical power, wherein the object side surface thereof is convex, and the image side surface thereof is concave; A seventh lens with negative optical power, wherein the object side surface thereof is convex at the paraxial region, and the image side surface thereof is concave; An eighth lens with positive optical power, wherein the object side surface thereof is convex, and the image side surface thereof is convex; Wherein a real image height IH corresponding to the maximum field of view of the optical lens and an effective focal length f of the optical lens satisfy: 2.7<IH / f<3.9; a combined focal length f5678 of the fifth lens, the sixth lens, the seventh lens and the eighth lens and the effective focal length f of the optical lens satisfy: 0.7<f5678 / f<1.

7.

2. The optical lens according to claim 1, characterized in that, The optical lens satisfies one or more of the following conditional expressions: an optical total length TTL of the optical lens and the effective focal length f of the optical lens satisfy: 5.7<TTL / f<8.2; the optical total length TTL of the optical lens and the real image height IH corresponding to the maximum field of view of the optical lens satisfy: 1.9<TTL / IH<2.

4.

3. The optical lens according to claim 1, characterized in that, The optical lens satisfies one or more of the following conditional expressions: a maximum field of view FOV of the optical lens and an F-number Fno of the optical lens satisfy: 48°<FOV / Fno<60°; the real image height IH corresponding to the maximum field of view of the optical lens and an entrance pupil diameter EPD of the optical lens satisfy: 7.5<IH / EPD<11.

4. The optical lens according to claim 1, characterized in that, The optical lens satisfies one or more of the following conditional expressions: the effective focal length f of the optical lens, the real image height IH corresponding to the maximum field of view of the optical lens and the maximum field of view FOV of the optical lens satisfy: 40°<f×FOV / IH<58°; a clear aperture half-diameter d1 of the object side surface of the first lens, the real image height IH corresponding to the maximum field of view of the optical lens and the maximum field of view FOV of the optical lens satisfy: 0.18<d1 / (IH / 2) / tan(FOV / 2)<0.34; the real image height IH corresponding to the maximum field of view of the optical lens, the effective focal length f of the optical lens and the radian value θ of the maximum half field of view of the optical lens satisfy: 1.05<(IH / 2) / (f×θ)<1.

3.

5. The optical lens according to claim 1, characterized in that, The optical lens satisfies one or more of the following conditional expressions: the focal length f1 of the first lens and the effective focal length f of the optical lens satisfy: -35<f1 / f<-5.7; the focal length f2 of the second lens and the effective focal length f of the optical lens satisfy: -5.3<f2 / f<-1.4; the focal length f3 of the third lens and the effective focal length f of the optical lens satisfy: -250<f3 / f<-4.8; the focal length f4 of the fourth lens and the effective focal length f of the optical lens satisfy: 1.3<f4 / f<2.4; the focal length f7 of the seventh lens and the effective focal length f of the optical lens satisfy: -5.7<f7 / f<-0.9; the focal length f8 of the eighth lens and the effective focal length f of the optical lens satisfy: 0.7<f8 / f<1.

4.

6. The optical lens according to claim 1, characterized in that, The optical lens satisfies one or more of the following conditional expressions: the focal length f5 of the fifth lens and the effective focal length f of the optical lens satisfy: 1.2<f5 / f<1.8; the radius of curvature R9 of the object-side surface of the fifth lens and the effective focal length f of the optical lens satisfy: 0.7<R9 / f<1; the radius of curvature R10 of the image-side surface of the fifth lens and the effective focal length f of the optical lens satisfy: 20<R10 / f<26.

7. The optical lens according to claim 1, characterized in that, The optical lens satisfies one or more of the following conditional expressions: the focal length f6 of the sixth lens and the effective focal length f of the optical lens satisfy: -1.4<f6 / f<-1; the radius of curvature R11 of the object-side surface of the sixth lens and the effective focal length f of the optical lens satisfy: 20<R11 / f<26; the radius of curvature R12 of the image-side surface of the sixth lens and the effective focal length f of the optical lens satisfy: 0.8<R12 / f<0.

9.

8. The optical lens according to claim 1, characterized in that, The optical lens satisfies one or more of the following conditional expressions: the combined focal length f1234 of the first lens, the second lens, the third lens and the fourth lens and the combined focal length f5678 of the fifth lens, the sixth lens, the seventh lens and the eighth lens satisfy: 1<f1234 / f5678<2.5; the focal length f5 of the fifth lens and the combined focal length f5678 of the fifth lens, the sixth lens, the seventh lens and the eighth lens satisfy: 0.8<f5 / f5678<2.1; the focal length f6 of the sixth lens and the combined focal length f5678 of the fifth lens, the sixth lens, the seventh lens and the eighth lens satisfy: -1.7<f6 / f5678<-0.

7.

9. The optical lens according to claim 1, characterized in that, The optical lens satisfies one or more of the following conditional expressions: the focal length f4 of the fourth lens and the focal length f5 of the fifth lens satisfy: 1<f4 / f5<1.6; the focal length f5 of the fifth lens and the focal length f6 of the sixth lens satisfy: -1.5<f5 / f6<-1; the focal length f6 of the sixth lens and the focal length f7 of the seventh lens satisfy: 0.2<f6 / f7<1.

3.

10. The optical lens according to claim 1, characterized in that, The optical lens satisfies one or more of the following conditional expressions: the real image height IH corresponding to the maximum field angle of the optical lens and the effective focal length f of the optical lens satisfy: 2.95<IH / f<3.56; the combined focal length f5678 of the fifth lens, the sixth lens, the seventh lens and the eighth lens and the effective focal length f of the optical lens satisfy: 0.77<f5678 / f<1.52.

Images