Optical lens

Abstract

The invention provides an optical lens, which comprises eight lenses with focal power and sequentially comprises a first lens with negative focal power, a second lens with positive focal power, a third lens with negative focal power, a fourth lens with negative focal power, a fifth lens with negative focal power and a sixth lens with negative focal power from an object side to an image side along an optical axis, the object side surface of the second lens is a concave surface, and the image side surface of the second lens is a convex surface; the object side surface of the third lens is a convex surface, and the image side surface of the third lens is a convex surface; the image side surface of the fourth lens is a convex surface; the fifth lens has negative focal power, the object side surface of the fifth lens is a convex surface near the optical axis, and the image side surface of the fifth lens is a concave surface; the sixth lens has positive focal power, and the image side surface of the sixth lens is a convex surface; the object side surface of the seventh lens is a convex surface near the optical axis, and the image side surface of the seventh lens is a convex surface; and the object side surface of the eighth lens is a convex surface near the optical axis, and the image side surface of the eighth lens is a concave surface near the optical axis. The optical lens provided by the invention has one or more advantages of large field angle, small distortion, low sensitivity, high imaging quality and the like.

Description

TECHNICAL FIELD

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

[0002] With the rapid development of electronic product performance and technology, the resolution of video conference equipment is continuously improved, from the common 1080P to 4K or even higher, and there are also higher requirements for image distortion. At present, the main video conference lens main camera adopts a target surface smaller than 1 / 2 inch, a full glass structure or a full plastic structure. Therefore, either the cost is too high or the volume is too large, or the poor heat resistance leads to defocus and image blur. Therefore, it is necessary to develop an optical lens with one or more advantages of high resolution, low cost, small volume, small distortion and the like, so as to better meet the market demand. SUMMARY

[0003] In view of the above problems, the purpose of the present application is to provide an optical lens with the advantages of excellent imaging quality.

[0004] The technical scheme adopted by the present application is as follows: An optical lens, which comprises eight lenses with optical power, and sequentially comprises, along the optical axis from the object side to the imaging surface: a first lens with negative optical power, whose object side surface is a convex surface and whose image side surface is a concave surface; a second lens with positive optical power, whose object side surface is a concave surface and whose image side surface is a convex surface; a third lens with positive optical power, whose object side surface is a convex surface and whose image side surface is a convex surface; a fourth lens with positive optical power, whose image side surface is a convex surface; a fifth lens with negative optical power, whose object side surface is a convex surface near the optical axis and whose image side surface is a concave surface; a sixth lens with positive optical power, whose image side surface is a convex surface; a seventh lens with positive optical power, whose object side surface is a convex surface near the optical axis and whose image side surface is a convex surface; an eighth lens with negative optical power, whose object side surface is a convex surface near the optical axis and whose image side surface is a concave surface near the optical axis; wherein 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: 2.5<IH / f<2.9; and the effective focal length f of the optical lens and the entrance pupil diameter EPDI of the optical lens satisfy: 1.7<f / EPDI<2.3.

[0005] Further preferably, the effective focal length f of the optical lens, the aperture value Fno of the optical lens and the total optical length TTL of the optical lens satisfy: 0.4<fxFno / TTL<0.75.

[0006] Further preferably, the focal length f1 of the first lens and the effective focal length f of the optical lens satisfy: -1.7 < f1 / f < -1.5; the focal length f1 of the first lens, the object side surface curvature radius R1 of the first lens and the image side surface curvature radius R2 of the first lens satisfy: -0.4 < f1 / (R1+R2) < -0.3.

[0007] Further preferably, the focal length f2 of the second lens and the effective focal length f of the optical lens satisfy: 6.4 < f2 / f < 12.2; the object side surface curvature radius R3 of the second lens and the image side surface curvature radius R4 of the second lens satisfy: 4 < (R3+R4) / (R3-R4) < 6.9.

[0008] Further preferably, the focal length f3 of the third lens and the effective focal length f of the optical lens satisfy: 1.2 < f3 / f < 2.2; the object side surface curvature radius R5 of the third lens and the effective focal length f of the optical lens satisfy: 1 < R5 / f < 2.1.

[0009] Further preferably, the focal length f4 of the fourth lens and the effective focal length f of the optical lens satisfy: 2 < f4 / f < 4.1; the image side surface curvature radius R8 of the fourth lens and the effective focal length f of the optical lens satisfy: -21 < R8 / f < -2.

[0010] Further preferably, the focal length f6 of the sixth lens and the effective focal length f of the optical lens satisfy: 8 < f6 / f < 29; the image side surface curvature radius R12 of the sixth lens and the effective focal length f of the optical lens satisfy: -5.8 < R12 / f < -2.

[0011] Further preferably, the focal length f7 of the seventh lens and the effective focal length f of the optical lens satisfy: 1.3 < f7 / f < 2; the image side surface curvature radius R14 of the seventh lens and the effective focal length f of the optical lens satisfy: -3.6 < R14 / f < -1.3.

[0012] Further preferably, the focal length f1 of the first lens, the focal length f2 of the second lens and the effective focal length f of the optical lens satisfy: 4.8 < (f1+f2) / f < 10.6.

[0013] Further preferably, the object side surface half sagittal height SAG81 of the eighth lens, the image side surface half sagittal height SAG82 of the eighth lens and the central thickness CT8 of the eighth lens satisfy: -1.8 < (SAG81+SAG82) / CT8 < -0.8.

[0014] The optical lens provided by the application adopts eight lenses with specific optical powers, and through specific surface shape matching and reasonable optical power distribution, the imaging quality of the optical lens is improved, the aberration is reduced, and the imaging quality of the optical lens is improved, so that the lens has one or more advantages of large field of view, large entrance pupil diameter, short total length, large aperture, large image surface, small distortion, and low sensitivity. BRIEF DESCRIPTION OF DRAWINGS

[0015] The above and / or additional aspects and advantages of the present application will become apparent and more readily appreciated from the following description of the embodiments, taken in conjunction with the accompanying drawings in which: Figure 1 FIG. 1 is a structural schematic diagram of an optical lens according to an embodiment of the present application.

[0016] Figure 2 FIG. 2 is an F-Tan(Theta) distortion curve diagram of the optical lens according to the embodiment 1 of the present application.

[0017] Figure 3 FIG. 3 is a field curvature curve diagram of the optical lens according to the embodiment 1 of the present application.

[0018] Figure 4 FIG. 4 is a sagittal color difference curve diagram of the optical lens according to the embodiment 1 of the present application.

[0019] Figure 5 FIG. 5 is a structural schematic diagram of an optical lens according to an embodiment of the present application.

[0020] Figure 6 FIG. 6 is an F-Tan(Theta) distortion curve diagram of the optical lens according to the embodiment 2 of the present application.

[0021] Figure 7 FIG. 7 is a field curvature curve diagram of the optical lens according to the embodiment 2 of the present application.

[0022] Figure 8 FIG. 8 is a sagittal color difference curve diagram of the optical lens according to the embodiment 2 of the present application.

[0023] Figure 9 FIG. 9 is a structural schematic diagram of an optical lens according to an embodiment of the present application.

[0024] Figure 10 FIG. 10 is an F-Tan(Theta) distortion curve diagram of the optical lens according to the embodiment 3 of the present application.

[0025] Figure 11 FIG. 11 is a field curvature curve diagram of the optical lens according to the embodiment 3 of the present application.

[0026] Figure 12 FIG. 12 is a sagittal color difference curve diagram of the optical lens according to the embodiment 3 of the present application.

[0027] The following detailed description, in conjunction with the accompanying drawings, will further illustrate the present invention. Detailed Implementation

[0028] 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.

[0029] 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.

[0030] 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.

[0031] 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.

[0032] 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.

[0033] Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. It will be further understood that terms, such as those defined in commonly used dictionaries, should be interpreted as having a meaning that is consistent with their meaning in the context of the relevant art and will not be interpreted in an idealized or overly formal sense unless expressly so defined herein.

[0034] It should be noted that the embodiments and features of the embodiments in the present application can be combined with each other without conflict. The present application will be described in detail below with reference to the drawings and in combination with the embodiments.

[0035] The optical lens provided by the embodiment of the present application comprises eight lenses with optical power, which are sequentially arranged along the optical axis from the object side to the imaging surface as 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.

[0036] In some embodiments, the first lens can have negative optical power, the object side surface thereof can be a convex surface, and the image side surface thereof can be a concave surface. The second lens can have positive optical power, the object side surface thereof can be a concave surface, and the image side surface thereof can be a convex surface. The third lens can have positive optical power, the object side surface thereof can be a convex surface, and the image side surface thereof can be a convex surface. The fourth lens can have positive optical power, the object side surface thereof can be a convex surface or a concave surface, and the image side surface thereof can be a convex surface. The fifth lens can have negative optical power, the object side surface thereof can be a convex surface at the near optical axis, and the image side surface thereof can be a concave surface. The sixth lens can have positive optical power, the object side surface thereof can be a concave surface or a convex surface at the near optical axis, and the image side surface thereof can be a convex surface. The seventh lens can have positive optical power, the object side surface thereof can be a convex surface at the near optical axis, and the image side surface thereof can be a convex surface. The eighth lens can have negative optical power, the object side surface thereof can be a convex surface at the near optical axis, and the image side surface thereof can be a concave surface at the near optical axis.

[0037] In some embodiments, the optical lens can further comprise a diaphragm, which can be located between the second lens and the third lens. It can be understood that the diaphragm is used to limit the amount of light to change the brightness of the imaging.

[0038] In some embodiments, the optical lens can further comprise a filter, which is arranged between the eighth lens and the imaging surface along the optical axis. The filter is used to filter out interference light to prevent the interference light from reaching the imaging surface of the optical lens and affecting normal imaging.

[0039] In some embodiments, a real image height IH corresponding to a maximum field of view angle of the optical lens satisfies: 2.5<IH / f<2.9; and an effective focal length f of the optical lens satisfies: 1.7<f / EPDI<2.3. Satisfying the above ranges, shortening the effective focal length can expand the field of view angle, so that the optical lens can capture a wider object space, and meanwhile, the optical lens can match a large image chip to improve the imaging quality of the optical lens. Meanwhile, controlling the ratio of the effective focal length of the optical lens to the entrance pupil diameter of the optical lens can help to improve the light receiving capability of the optical lens, so as to obtain imaging information with higher brightness and resolution.

[0040] In some embodiments, an effective focal length f of the optical lens, an aperture value Fno of the optical lens, and an optical total length TTL of the optical lens satisfy: 0.4<fxFno / TTL<0.75. Satisfying the above ranges, the optical lens satisfies the characteristics of short focal length and large aperture, so that the optical lens has sufficient light amount, can capture more scene information with a large wide-angle field of view, and can control the depth of field flexibly to strengthen the picture layering, thereby being beneficial to capturing a clearer image. Meanwhile, the limitation of the optical total length makes the optical lens satisfy miniaturization.

[0041] In some embodiments, a focal length f1 of the first lens and an effective focal length f of the optical lens satisfy: -1.7<f1 / f<-1.5; and the focal length f1 of the first lens, a curvature radius R1 of an object side surface of the first lens, and a curvature radius R2 of an image side surface of the first lens satisfy: -0.4<f1 / (R1+R2)<-0.3. Satisfying the above ranges, the first lens has negative refractive power, can capture light rays with a large angle entering the optical lens, expand the field of view angle range of the optical lens, and is beneficial to reducing the sensitivity of the optical lens and realizing miniaturization design of the optical lens. Meanwhile, controlling the surface shape of the first lens is beneficial to reducing the bending degree of the light rays at the image side surface of the first lens, reducing the astigmatism amount of the optical lens, balancing the astigmatism problem caused by the large field of view angle of the optical lens, so that the optical lens has a large field of view while the astigmatism is not too large, and thus the optical lens has excellent imaging quality.

[0042] In some embodiments, the focal length f2 of the second lens and the effective focal length f of the optical lens satisfy: 6.4 < f2 / f < 12.2; the radius of curvature R3 of the object side surface of the second lens and the radius of curvature R4 of the image side surface of the second lens satisfy: 4 < (R3+R4) / (R3-R4) < 6.9. Satisfying the above ranges, the second lens has positive refractive power, cooperates with the first lens to make large-angle light incident into the optical lens, is beneficial to expanding the field of view of the optical lens, corrects the astigmatism and chromatic aberration of the optical lens, and improves the imaging quality of the optical lens. At the same time, the surface shape of the second lens is reasonably set, so that the object side surface and the image side surface of the second lens are close to concentric circular structures, which effectively improves the astigmatism, distortion and coma of the optical lens, and further improves the imaging quality of the optical lens.

[0043] 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 < 2.2; the radius of curvature R5 of the object side surface of the third lens and the effective focal length f of the optical lens satisfy: 1 < R5 / f < 2.1. Satisfying the above ranges, the third lens has positive refractive power, which is beneficial to adjusting the light path from the first lens and the second lens, so that the optical lens has certain large field of view, low sensitivity and small size characteristics. At the same time, the object side surface of the third lens is set as a convex surface, which can make the light passing through the second lens shrink into the third lens, is beneficial to reducing the size of the rear lens, and is helpful to realize the small size characteristics of the optical lens. And the third lens can effectively reduce the spherical aberration and astigmatism to improve the imaging quality of the optical lens.

[0044] In some embodiments, the focal length f4 of the fourth lens and the effective focal length f of the optical lens satisfy: 2 < f4 / f < 4.1; the radius of curvature R8 of the image side surface of the fourth lens and the effective focal length f of the optical lens satisfy: -21 < R8 / f < -2. Satisfying the above ranges, the fourth lens has positive refractive power, which can effectively improve the aberration of the edge field of view and improve the overall imaging quality. At the same time, the surface shape of the image side surface of the fourth lens is controlled, which can effectively correct the spherical aberration of the optical lens, reduce the influence of astigmatism on the imaging of the optical lens, adjust the light path, and make the optical lens have large field of view and ultra-thin characteristics.

[0045] In some embodiments, the focal length f6 of the sixth lens and the effective focal length f of the optical lens satisfy: 8 < f6 / f < 29; the image-side surface curvature radius R12 of the sixth lens and the effective focal length f of the optical lens satisfy: -5.8 < R12 / f < -2. Satisfying the above ranges, the sixth lens has positive refractive power, which can limit the light path, correct chromatic aberration, reduce the sensitivity to decentration, correct system aberration, and improve imaging resolution. Meanwhile, the surface shape of the image side of the sixth lens is controlled, and thus the edge ray path of the image side of the sixth lens is controlled, so that the optical lens can accept a larger angle of light, which is beneficial to reducing the distortion of the optical lens. Meanwhile, the turning angle of the light reaching the sixth lens is small, which is beneficial to reducing the tolerance sensitivity of the optical lens.

[0046] In some embodiments, the focal length f7 of the seventh lens and the effective focal length f of the optical lens satisfy: 1.3 < f7 / f < 2; the image-side surface curvature radius R14 of the seventh lens and the effective focal length f of the optical lens satisfy: -3.6 < R14 / f < -1.3. Satisfying the above ranges, the seventh lens provides a strong positive refractive power for the optical lens, which can effectively correct chromatic aberration and correct the aberration caused by the decentration of each lens on the object side, that is, the sensitivity to decentration of the optical lens is reduced, the astigmatism caused by the decentration of each lens on the object side is suppressed, thereby correcting the aberration of the optical lens and improving the imaging resolution. Meanwhile, the surface shape of the image side of the seventh lens is controlled, which can effectively correct the spherical aberration of the optical lens, reduce the influence of astigmatism on the imaging of the optical lens, and also adjust the light path, so that the optical lens has a large field of view and an ultrathin feature.

[0047] In some embodiments, the focal length f1 of the first lens, the focal length f2 of the second lens, and the effective focal length f of the optical lens satisfy: 4.8 < (f1+f2) / f < 10.6. Satisfying the above ranges, the ratio of the sum of the effective focal lengths of the first lens and the second lens to the effective focal length of the optical lens is reasonably configured, which is beneficial to the mutual correction of the aberration caused by the first lens and the second lens, thereby improving the imaging quality of the optical lens and converging the incident angle of the light entering the stop to ensure a large field of view.

[0048] In some embodiments, the eighth lens satisfies: -1.8 < (SAG81 + SAG82) / CT8 < -0.8. Satisfying the above range can control the refractive power and thickness of the eighth lens at different positions in the direction perpendicular to the optical axis, avoid the eighth lens being too thick or too thin, reduce the incidence angle of light on the object side of the eighth lens, and reduce the tolerance sensitivity of the optical lens. Meanwhile, the eighth lens has multiple inflection points, which can correct the distortion and field curvature generated by the object side lens of the eighth lens, and make the refractive power of the multiple lenses close to the imaging surface of the optical lens be uniformly distributed.

[0049] In some embodiments, the first lens satisfies: 11 < R1 / SAG11 < 33. Satisfying the above range can reasonably control the ratio between the curvature radius of the object side of the first lens and the sag at the maximum effective aperture, provide negative refractive power for the optical lens, capture light rays with large angles entering the optical lens, expand the field angle range of the optical lens, and achieve the large field angle characteristics of the optical lens.

[0050] In some embodiments, the fifth lens satisfies: -2.4 < f5 / f < -1.7. Satisfying the above range can expand the width of the light beam exiting the optical lens, and the fifth lens located in the middle position has a certain negative focal power, which is beneficial to the photosensitive element to receive light carrying image information with the maximum area, and ensures the high-pixel imaging quality of the optical imaging lens.

[0051] In some embodiments, the eighth lens satisfies: -2.8 < f8 / f < -1.3. Satisfying the above range can expand the width of the light beam, so that the light beam with a large angle expands in width after passing through the first lens to the seventh lens, and the wide light beam is fully incident on the imaging surface of the optical lens, which realizes the large target surface imaging characteristics and is beneficial to high-pixel imaging.

[0052] In some embodiments, the seventh lens satisfies: -0.4 < SAG71 / CT7 ≤ -0.03. Satisfying the above range can make the surface shape and thickness of the seventh lens reasonable, thereby ensuring that the seventh lens has good optical performance and molding yield, and at the same time, the seventh lens has good assembly stability.

[0053] In some embodiments, the object-side half-aperture radius CSD11 of the first lens and the object-side half-aperture radius CSD81 of the eighth lens satisfy: 0.8 < CSD11 / CSD81 < 0.95. Satisfying the above range, the optical lens has a larger aperture, can better realize large-angle light collection, realize large-aperture imaging of the optical lens, and can increase the imaging area of the optical lens, realizing large-target imaging of the optical lens.

[0054] In some embodiments, the optical lens satisfies the following conditional expressions: 4.1 mm < f < 4.3 mm; 1.8 mm < EPDI < 2.4 mm; 13.5 mm < TTL < 19 mm; 1.75 < Fno < 2.3; 10.5 mm < IH < 12 mm; 18° < CRA < 30°. In the above conditional expressions, f represents the effective focal length of the optical lens, EPDI 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 real image height corresponding to the maximum field angle of the optical lens, and CRA represents the chief ray angle of incidence at the maximum image height of the optical lens. Satisfying the above range, the optical lens has one or more advantages of large field angle, large entrance pupil diameter, short total length, large aperture, large image surface, small distortion, and low sensitivity.

[0055] In some embodiments, the lens material in the optical lens provided by the present application can be glass or plastic. When the lens material is plastic, the production cost can be effectively reduced. When the lens material is glass, the geometric chromatic aberration of the optical system can be effectively corrected by the low dispersion characteristic of the glass itself. The third lens in the optical lens provided by the present application can be made of glass, and the first lens, the second lens, the fourth lens, the fifth lens, the sixth lens, the seventh lens, and the eighth lens can be made of plastic. The use of a glass-plastic hybrid structure can effectively reduce the cost, correct the aberration, reduce the size, improve the thermal stability, and provide an optical lens product with higher cost performance.

[0056] 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 a spherical lens or an aspherical lens. Compared with a spherical structure, an 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 realizing miniaturization of the lens. More specifically, 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 in the present application are all aspherical lenses.

[0057] In various embodiments of the present application, when the lens is an aspherical lens, the shape of each aspherical surface of the optical lens satisfies the following equation: ; wherein z is the distance of the curved surface to the vertex of the curved surface in the direction of the optical axis, h is the distance of the optical axis to the curved surface, c is the curvature of the vertex of the curved surface, K is the coefficient of the quadratic surface, and B, C, D, E, F, G, and H are the coefficients of the fourth-order, sixth-order, eighth-order, tenth-order, twelfth-order, fourteenth-order, and sixteenth-order curved surfaces, respectively.

[0058] The application will be further described in the following embodiments. In each embodiment, the thickness, the radius of curvature, and the material selection of each lens in the optical lens are different, and the specific differences can be referred to the parameter table of each embodiment. The following embodiments are merely the preferred embodiments of the application, but the embodiments of the application are not limited to the following embodiments only, and any change, replacement, combination, or simplification made without departing from the innovative points of the application should be regarded as equivalent replacement, and should be included in the protection scope of the application.

[0059] Embodiment 1 Please refer to Figure 1 , which is a structural schematic diagram of an optical lens 100 provided in the embodiment 1 of the application. The optical lens 100 includes, in sequence from the object side to the imaging surface along the optical axis, a first lens L1, a second lens L2, a stop ST, a third lens L3, a fourth lens L4, a fifth lens L5, a sixth lens L6, a seventh lens L7, an eighth lens L8, and a filter G1.

[0060] The first lens L1 has a negative focal power, the object side surface S1 thereof is a convex surface, and the image side surface S2 thereof is a concave surface; The second lens L2 has a positive focal power, the object side surface S3 thereof is a concave surface, and the image side surface S4 thereof is a convex surface; The third lens L3 has a positive focal power, the object side surface S5 thereof is a convex surface, and the image side surface S6 thereof is a convex surface; The fourth lens L4 has a positive focal power, the object side surface S7 thereof is a convex surface, and the image side surface S8 thereof is a convex surface; The fifth lens L5 has a negative focal power, the object side surface S9 thereof is a convex surface at the near optical axis, and the image side surface S10 thereof is a concave surface; The sixth lens L6 has a positive focal power, the object side surface S11 thereof is a concave surface at the near optical axis, and the image side surface S12 thereof is a convex surface; The seventh lens L7 has a positive focal power, the object side surface S13 thereof is a convex surface at the near optical axis, and the image side surface S14 thereof is a convex surface; The eighth lens L8 has a negative focal power, the object side surface S15 thereof is a convex surface at the near optical axis, and the image side surface S16 thereof is a concave surface at the near optical axis; The object side surface S17 and the image side surface S18 of the filter G1 are both flat surfaces; The imaging surface S19 is a flat surface.

[0061] The third lens L3 is a glass aspherical lens, and the first lens L1, the second lens L2, the fourth lens L4, the fifth lens L5, the sixth lens L6, the seventh lens L7, and the eighth lens L8 are plastic aspherical lenses.

[0062] The related parameters of the lenses in the optical lens 100 in Embodiment 1 are shown in Table 1-1.

[0063] Table 1-1 The surface parameters of the aspherical lenses in the optical lens 100 in Embodiment 1 are shown in Table 1-2.

[0064] Table 1-2 In this embodiment, the F-Tan(Theta) distortion curve, the field curvature curve, and the axial chromatic aberration curve of the optical lens 100 are shown in Figure 2 、 Figure 3 、 Figure 4 .

[0065] Figure 2 The F-Tan(Theta) distortion curve of Embodiment 1 is shown, which represents the distortion of light rays of different wavelengths at different image heights on the imaging plane, the horizontal axis represents the distortion value (unit: %), and the vertical axis represents the half field angle (unit: °). As can be seen from the figure, the distortion of the optical lens is controlled within-8%~2%, which shows that the optical lens 100 can well correct the distortion.

[0066] Figure 3 The field curvature curve of Embodiment 1 is shown, which represents the curvature degree of light rays of different wavelengths on the meridional image surface and the sagittal image surface, the horizontal axis represents the offset (unit: mm), and the vertical axis represents the half field angle (unit: °). As can be seen from the figure, the field curvature of the meridional image surface and the sagittal image surface is controlled within ±0.05mm, which shows that the optical lens 100 can well correct the field curvature.

[0067] Figure 4 The axial chromatic aberration curve of Embodiment 1 is shown, which represents the chromatic aberration of each wavelength relative to the central wavelength (0.555μm) at different image heights on the imaging plane, the horizontal axis represents the axial chromatic aberration value of each wavelength relative to the central wavelength (unit: μm), and the vertical axis represents the normalized field angle. As can be seen from the figure, the axial chromatic aberration of the longest wavelength and the shortest wavelength is controlled within-2μm~5μm, which shows that the optical lens can very well correct the chromatic aberration of the edge field and the secondary spectrum of the entire image surface.

[0068] Embodiment 2 Please refer to Figure 5The 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 object side surface S7 of the fourth lens L4 is concave; the optical parameters such as the radius of curvature and lens thickness of each lens surface are different.

[0069] The relevant parameters of each lens in the optical lens 200 in Example 2 are shown in Table 2-1.

[0070] Table 2-1 The surface profile parameters of the aspherical lens of the optical lens 200 in Example 2 are shown in Table 2-2.

[0071] Table 2-2 In this embodiment, the F-Tan (Theta) distortion curve, field curvature curve, and transverse chromatic aberration curve of the optical lens 200 are as follows: Figure 6 , Figure 7 , Figure 8 As shown.

[0072] from Figure 6 As can be seen, the distortion of the optical lens is controlled within -5% to 2%, indicating that the optical lens 200 can correct distortion well.

[0073] from Figure 7 As can be seen, the field curvature of the meridional and sagittal image planes is controlled within -0.05mm to 0.1mm, indicating that the optical lens 200 can effectively correct field curvature.

[0074] from Figure 8 As can be seen, the transverse chromatic aberration of the longest and shortest wavelengths is controlled within 0μm~5μm, indicating that the optical lens can correct the chromatic aberration at the edge of the field of view and the secondary spectrum of the entire image plane very well.

[0075] Example 3 Please see Figure 9 The figure shows a schematic diagram of the structure of the optical lens 300 provided in Embodiment 3 of the present invention. The main difference between this embodiment and Embodiment 1 is that the object side surface S11 of the sixth lens L6 is convex near the optical axis; the optical parameters such as the radius of curvature and lens thickness of each lens surface are different.

[0076] The relevant parameters of each lens in the optical lens 300 in Example 3 are shown in Table 3-1.

[0077] Table 3-1 The surface shape parameters of the aspherical lens of the optical lens 300 in Embodiment 3 are shown in Table 3-2.

[0078] Table 3-2 In this embodiment, the F-Tan(Theta) distortion curve, the field curvature curve, and the axial chromatic aberration curve of the optical lens 300 are shown in Figure 10 、 Figure 11 、 Figure 12

[0079] As can be seen from Figure 10 , the distortion of the optical lens is controlled within -16%~0%, which indicates that the optical lens 300 can correct the distortion.

[0080] As can be seen from Figure 11 , the field curvature of the sagittal image surface and the tangential image surface is controlled within ±0.05mm, which indicates that the optical lens 300 can correct the field curvature well.

[0081] As can be seen from Figure 12 , the axial chromatic aberration of the longest wavelength and the shortest wavelength is controlled within -2μm~4μm, which indicates that the optical lens can correct the chromatic aberration of the edge field of view and the secondary spectrum of the entire image surface very well.

[0082] Please refer to Table 4 for the optical characteristics corresponding to each of the above embodiments, including the effective focal length f, the total optical length TTL, the aperture value Fno, the chief ray angle of incidence CRA at the maximum image height, the real image height IH corresponding to the maximum field of view angle, the maximum field of view angle FOV, the entrance pupil diameter EPDI, and the numerical value corresponding to each conditional expression in each embodiment.

[0083] Table 4 In summary of the above embodiments, the optical lens provided by the present application adopts eight lenses with specific optical power, and through specific surface shape matching and reasonable optical power distribution, the imaging quality of the optical lens can be improved, the aberration can be reduced, and the imaging quality of the optical lens can be improved, so that the lens has one or more advantages of large field of view angle, large entrance pupil diameter, short total length, large aperture, large image surface, small distortion, and low sensitivity.

[0084] ​In the description of the present specification, the description of the terms "one embodiment", "some embodiments", "an example", "a specific example", or "some examples" and the like means that the specific features, structures, materials or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present application. In the present 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 can be combined in any one or more embodiments or examples in a suitable manner.

[0085] The above-described embodiments only express several implementation manners of the present application, which are described in a more specific and detailed manner, but cannot be understood as a limitation on the patent scope of the present application. It should be noted that, for those of ordinary skill in the art, several modifications and improvements can be made without departing from the concept of the present application, which are all within the protection scope of the present application. Therefore, the protection scope of the patent of the present application should be subject to the appended claims.

Claims

1. An optical lens, eight pieces of lenses with optical power, characterized in that, In order from the object side to the imaging plane along the optical axis, successively comprise: a first lens with negative refractive power, the object side surface of which is convex, and the image side surface of which is concave; a second lens with positive refractive power, the object side surface of which is concave, and the image side surface of which is convex; a third lens with positive refractive power, the object side surface of which is convex, and the image side surface of which is convex; a fourth lens with positive refractive power, the image side surface of which is convex; a fifth lens with negative refractive power, the object side surface of which is convex at the near optical axis, and the image side surface of which is concave; a sixth lens with positive refractive power, the image side surface of which is convex; a seventh lens with positive refractive power, the object side surface of which is convex at the near optical axis, and the image side surface of which is convex; an eighth lens with negative refractive power, the object side surface of which is convex at the near optical axis, and the image side surface of which is concave at the near optical axis; wherein 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: 2.5<IH / f<2.9; and the effective focal length f of the optical lens and the entrance pupil diameter EPDI of the optical lens satisfy: 1.7<f / EPDI<2.

3.

2. The optical lens of claim 1, wherein, The effective focal length f of the optical lens, the aperture value Fno of the optical lens, and the total optical length TTL of the optical lens satisfy: 0.4<f×Fno / TTL<0.

75.

3. The optical lens of claim 1, wherein, The focal length f1 of the first lens and the effective focal length f of the optical lens satisfy: -1.7<f1 / f<-1.5; and the focal length f1 of the first lens, the object side surface curvature radius R1 of the first lens, and the image side surface curvature radius R2 of the first lens satisfy: -0.4<f1 / (R1+R2)<-0.

3.

4. The optical lens of claim 1, wherein, The focal length f2 of the second lens and the effective focal length f of the optical lens satisfy: 6.4<f2 / f<12.2; and the object side surface curvature radius R3 of the second lens and the image side surface curvature radius R4 of the second lens satisfy: 4<(R3+R4) / (R3-R4)<6.

9.

5. The optical lens of claim 1, wherein, The focal length f3 of the third lens and the effective focal length f of the optical lens satisfy: 1.2<f3 / f<2.2; and the object side surface curvature radius R5 of the third lens and the effective focal length f of the optical lens satisfy: 1<R5 / f<2.

1.

6. The optical lens of claim 1, wherein, The focal length f4 of the fourth lens and the effective focal length f of the optical lens satisfy: 2<f4 / f<4.1; and the image side surface curvature radius R8 of the fourth lens and the effective focal length f of the optical lens satisfy: -21<R8 / f<-2.

7. The optical lens of claim 1, wherein, The focal length f6 of the sixth lens and the effective focal length f of the optical lens satisfy: 8<f6 / f<29; and the image side surface curvature radius R12 of the sixth lens and the effective focal length f of the optical lens satisfy: -5.8<R12 / f<-2.

8. The optical lens of claim 1, wherein, The focal length f7 of the seventh lens and the effective focal length f of the optical lens satisfy: 1.3<f7 / f<2; and the image side surface curvature radius R14 of the seventh lens and the effective focal length f of the optical lens satisfy: -3.6<R14 / f<-1.

3.

9. The optical lens of claim 1, wherein, The focal length f1 of the first lens, the focal length f2 of the second lens and the effective focal length f of the optical lens satisfy: 4.8<(f1+f2) / f<10.

6.

10. The optical lens of claim 1, wherein, The object side half-field aperture height SAG81 of the eighth lens, the image side half-field aperture height SAG82 of the eighth lens and the central thickness CT8 of the eighth lens satisfy: -1.8<(SAG81+SAG82) / CT8<-0.8.

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