Optical lens

Abstract

The invention provides an optical lens, which comprises eight lenses from an object side to an imaging surface along an optical axis: a first lens with negative focal power, a second lens with negative 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, 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 negative focal power, and the object side surface of the sixth lens is a concave surface near the optical axis; the object side surface of the seventh lens is a convex surface, 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 in a paraxial position, and the image side surface of the eighth lens is a concave surface in a paraxial position. 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. As such, either the cost is too high and the volume is too large, or the heat resistance is poor, resulting in 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 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 negative optical power, whose object side surface is a concave surface near the optical axis; a seventh lens with positive optical power, whose object side surface is a convex surface 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 total optical length TTL of the optical lens and the real image height IH corresponding to the maximum field angle of the optical lens satisfy: 1.1 < TTL / IH < 1.6.

[0005] Further preferably, the real image height IH corresponding to the maximum field angle of the optical lens and the entrance pupil diameter EPDI of the optical lens satisfy: 5.2 < IH / EPDI < 6.2.

[0006] It is further preferred that the effective focal length f of the optical lens and the aperture value Fno of the optical lens satisfy: 1.8mm < f / Fno < 2.3mm.

[0007] It is further preferred that the focal length f1 of the first lens and the effective focal length f of the optical lens satisfy: -1.7 < f1 / f < -1.3; 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.

[0008] It is further preferred that the focal length f2 of the second lens and the effective focal length f of the optical lens satisfy: 5 < f2 / f < 13.

[0009] It is further preferred that the focal length f3 of the third lens and the effective focal length f of the optical lens satisfy: 1.1 < f3 / f < 2.3.

[0010] It is further preferred that the focal length f4 of the fourth lens and the effective focal length f of the optical lens satisfy: 2.1 < f4 / f < 9.7; the image side surface curvature radius R8 of the fourth lens and the focal length f4 of the fourth lens satisfy: -1.2 < R8 / f4 < -0.5.

[0011] It is further preferred that the focal length f5 of the fifth lens and the effective focal length f of the optical lens satisfy: -2.4 < f5 / f < -1.9; the distance CT56 of the fifth lens and the sixth lens on the optical axis and the focal length f5 of the fifth lens satisfy: -0.2 ≤ CT56 / f5 ≤ -0.1.

[0012] It is further preferred that the focal length f7 of the seventh lens and the effective focal length f of the optical lens satisfy: 0.6 < f7 / f < 1.4.

[0013] It is further preferred that the focal length f8 of the eighth lens and the effective focal length f of the optical lens satisfy: -2 < f8 / f < -1; the object side surface curvature radius R15 of the eighth lens and the image side surface curvature radius R16 of the eighth lens satisfy: 0.4 < (R15-R16) / (R15+R16) < 0.6.

[0014] It is further preferred that the object side surface half-hydraulic radius sag of the eighth lens, the image side surface half-hydraulic radius sag of the eighth lens and the central thickness CT8 of the eighth lens satisfy: -1.5 ≤ (SAG81+SAG82) / CT8 ≤ -0.7.

[0015] 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

[0016] 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 in Embodiment 1 of the present application.

[0017] Figure 2 FIG. 2 is an F-Tan(Theta) distortion curve diagram of the optical lens in Embodiment 1 of the present application.

[0018] Figure 3 FIG. 3 is a field curvature curve diagram of the optical lens in Embodiment 1 of the present application.

[0019] Figure 4 FIG. 4 is a sagittal chromatic aberration curve diagram of the optical lens in Embodiment 1 of the present application.

[0020] Figure 5 FIG. 5 is a structural schematic diagram of an optical lens in Embodiment 2 of the present application.

[0021] Figure 6 FIG. 6 is an F-Tan(Theta) distortion curve diagram of the optical lens in Embodiment 2 of the present application.

[0022] Figure 7 FIG. 7 is a field curvature curve diagram of the optical lens in Embodiment 2 of the present application.

[0023] Figure 8 FIG. 8 is a sagittal chromatic aberration curve diagram of the optical lens in Embodiment 2 of the present application.

[0024] Figure 9 FIG. 9 is a structural schematic diagram of an optical lens in Embodiment 3 of the present application.

[0025] Figure 10 FIG. 10 is an F-Tan(Theta) distortion curve diagram of the optical lens in Embodiment 3 of the present application.

[0026] Figure 11 FIG. 11 is a field curvature curve diagram of the optical lens in Embodiment 3 of the present application.

[0027] Figure 12 FIG. 12 is a sagittal chromatic aberration curve diagram of the optical lens in Embodiment 3 of the present application.

[0028] The following detailed description will further explain the present application with reference to the accompanying drawings. DETAILED DESCRIPTION

[0029] For a better understanding of the present application, various aspects of the present application will be described in relation to the annexed drawings. It is stressed that these descriptions are only illustrative of embodiments of the present application and are not meant to limit the scope of the present application in any way. Throughout the present description, like reference numerals refer to similar parts. The expression "and / or" includes any and all combinations of one or more of the associated listed items.

[0030] It is noted that, in this description, the terms first, second, third, etc., are used only to distinguish one feature from another, and do not imply any limitation on the features. Thus, a first lens discussed below could also be termed a second lens or a third lens, without departing from the teachings of the present application.

[0031] In the drawings, the thickness, size, and shape of the lenses have been exaggerated slightly for the sake of explanation. Specifically, the shape of the spherical or aspherical surfaces shown in the drawings is shown by way of example. That is, the shape of the spherical or aspherical surfaces is not limited to the shape of the spherical or aspherical surfaces shown in the drawings. The drawings are merely examples and are not drawn to scale.

[0032] In this description, the paraxial region refers to a region near the optical axis. If a lens surface is convex and the position of the convex surface is not specified, it means that the lens surface is convex at least in the paraxial region. If a lens surface is concave and the position of the concave surface is not specified, it means that the lens surface is concave at least in the paraxial region. The surface of each lens closest to the object is referred to as the object side surface of the lens, and the surface of each lens closest to the image plane is referred to as the image side surface of the lens.

[0033] It is also to be understood that the use of the terms "including", "comprising", "having" and / or "containing" when used in this specification, particularly in the claims, means that there are no restrictions on the presence of one or more other features, elements, components, and / or combinations thereof. In addition, the use of the term "at least one" when used in this specification, particularly in the claims, means that there is one or more of the listed features, elements, components, and / or combinations thereof. Furthermore, the use of the term "about" when used in this specification, particularly in the claims, means that there are no restrictions on the values of the elements, and that the values of the elements can vary by more than 10% of the value. Moreover, the use of the term "example" when used in this specification, particularly in the claims, means that the example is an example of one or more embodiments of the present application. Furthermore, the use of the term "exemplary" when used in this specification, particularly in the claims, means that the example is an example of one or more embodiments of the present application.

[0034] 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.

[0035] 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 accompanying drawings and in conjunction with the embodiments.

[0036] 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.

[0037] In some embodiments, the first lens can have a 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 a positive optical power, the object side surface thereof can be a convex surface or a concave surface near the optical axis, and the image side surface thereof can be a convex surface. The third lens can have a 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 a 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 a negative optical power, the object side surface thereof can be a convex surface near the optical axis, and the image side surface thereof can be a concave surface. The sixth lens can have a negative optical power, the object side surface thereof can be a concave surface near the optical axis, and the image side surface thereof can be a concave surface or a convex surface near the optical axis. The seventh lens can have a 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 eighth lens can have a negative optical power, the object side surface thereof can be a convex surface near the optical axis, and the image side surface thereof can be a concave surface near the optical axis.

[0038] 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.

[0039] 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.

[0040] In some embodiments, the total optical length TTL of the optical lens and the real image height IH corresponding to the maximum field angle of the optical lens satisfy: 1.1 < TTL / IH < 1.6. Satisfying the above range can ensure that the optical lens has high pixels while effectively shortening the total optical length of the optical lens, so that the optical lens meets the miniaturization while having high imaging quality.

[0041] In some embodiments, a real image height IH corresponding to a maximum field of view angle of the optical lens and an entrance pupil diameter EPDI of the optical lens satisfy: 5.2<IH / EPDI<6.2. With the above range satisfied, the optical lens has a large image surface, a large entrance pupil diameter and a high light throughput, thereby increasing the imaging effect of the optical lens when working in a dark environment, so as to reduce the aberration of the edge field of view.

[0042] In some embodiments, an effective focal length f of the optical lens and an aperture value Fno of the optical lens satisfy: 1.8mm<f / Fno<2.3mm. With the above range satisfied, the optical lens has a large aperture, so that the optical lens has sufficient light quantity, thereby making the captured image clearer. At the same time, the problem of weak light shooting is solved by a large aperture, and the depth of field is controlled flexibly to strengthen the picture layering.

[0043] 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<-1.3; the focal length f1 of the first lens, a curvature radius R1 of the object side of the first lens and a curvature radius R2 of the image side of the first lens satisfy: -0.4<f1 / (R1+R2)<-0.3. With the above range satisfied, the first lens is defined to have a negative focal power, so that the light rays with a large angle of incidence can be captured by the optical lens, thereby expanding the field of view angle of the optical lens. At the same time, the sensitivity of the optical lens is reduced, and the miniaturization design is realized. At the same time, the surface shape of the first lens is reasonably set, so as to reduce the bending degree of the light rays at the image side of the first lens, reduce the astigmatism of the optical lens, balance the astigmatism problem caused by the large field of view angle, so that the optical lens has a large field of view without excessive astigmatism, thereby ensuring that the optical lens has excellent imaging quality.

[0044] In some embodiments, a focal length f2 of the second lens and an effective focal length f of the optical lens satisfy: 5<f2 / f<13. With the above range satisfied, the light rays with a large angle of incidence are incident into the optical lens in cooperation with the first lens, thereby expanding the field of view angle of the optical lens. At the same time, the astigmatism and chromatic aberration are corrected, and the imaging quality of the optical lens is improved.

[0045] In some embodiments, a focal length f3 of the third lens and an effective focal length f of the optical lens satisfy: 1.1<f3 / f<2.3. With the above range satisfied, the third lens is defined to have a positive focal power, and the ratio of the focal power of the third lens is defined, so as to adjust the light ray trend from the first lens and the second lens, so that the optical lens has a large field of view angle, low sensitivity and miniaturization characteristics.

[0046] In some embodiments, the focal length f4 of the fourth lens and the effective focal length f of the optical lens satisfy: 2.1 < f4 / f < 9.7; the image-side surface curvature radius R8 of the fourth lens and the focal length f4 of the fourth lens satisfy: -1.2 < R8 / f4 < -0.5. By setting the fourth lens to have a relatively large positive refractive power, the aberration of the edge field of view can be effectively improved, and the overall imaging quality of the optical lens can be improved, when the above ranges are satisfied. Meanwhile, the optical power of the fourth lens and the surface shape of the image-side surface are reasonably limited, which is conducive to converging light rays while reducing the deflection angle of the light rays, shortening the distance of the light rays reaching the next lens, and reducing the total length of the lens.

[0047] In some embodiments, the focal length f5 of the fifth lens and the effective focal length f of the optical lens satisfy: -2.4 < f5 / f < -1.9; the distance CT56 between the fifth lens and the sixth lens on the optical axis and the focal length f5 of the fifth lens satisfy: -0.2 ≤ CT56 / f5 ≤ -0.1. When the above ranges are satisfied, the fifth lens has a certain negative optical power, which can expand the width of the incident light beam exiting the optical lens, is conducive to the maximum area of the photosensitive element receiving light rays carrying image information, and ensures the high-pixel imaging quality of the optical lens. Meanwhile, the optical lens can have a certain back focus on the basis of being miniaturized, which reduces the assembly interference between the optical lens and the imaging chip, and also makes the total length of the optical lens shorter and the structure more compact.

[0048] In some embodiments, the focal length f7 of the seventh lens and the effective focal length f of the optical lens satisfy: 0.6 < f7 / f < 1.4. When the above ranges are satisfied, the positive refractive power strength provided by the seventh lens to the optical lens can be better constrained to correct the rear-end light rays, thereby effectively correcting chromatic aberration. Meanwhile, as a lens at the rear end of the optical lens, the seventh lens can correct the aberration caused by the decentration of each lens on the object side, that is, the decentration sensitivity of the optical lens can be reduced, the astigmatism caused by the decentration of each lens on the object side can be suppressed, thereby correcting the aberration of the optical lens and improving the imaging resolution.

[0049] In some embodiments, the focal length f8 of the eighth lens and the effective focal length f of the optical lens satisfy: -2 < f8 / f < -1; the object-side surface curvature radius R15 of the eighth lens and the image-side surface curvature radius R16 of the eighth lens satisfy: 0.4 < (R15-R16) / (R15+R16) < 0.6. When the above ranges are satisfied, the eighth lens is limited to have a negative optical power, which is conducive to expanding the width of the light beam, so that the light beam with a large angle is expanded 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 satisfies the large target surface imaging and is conducive to realizing high-pixel imaging. Meanwhile, the surface shape of the eighth lens is reasonably limited, which can correct the aberration caused by the front lens, is conducive to improving the imaging quality of the optical lens, and reduces the difficulty of forming the eighth lens.

[0050] In some embodiments, the object-side half-aperture sag of the eighth lens SAG81, the image-side half-aperture sag of the eighth lens SAG82, and the center thickness of the eighth lens CT8 satisfy: -1.5≤(SAG81+SAG82) / CT8≤-0.7. Satisfying the above range helps to control the refractive power and thickness of the eighth lens at different positions 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 surface of the eighth lens, and reduce the tolerance sensitivity of the optical lens. Meanwhile, the eighth lens has multiple inflection points, which helps to correct the distortion and field curvature generated by the object-side lens of the eighth lens, and makes the refractive power of multiple lenses close to the imaging surface of the optical lens be uniformly distributed.

[0051] In some embodiments, the maximum field of view FOV of the optical lens and the chief ray angle of incidence CRA at the maximum image height of the optical lens satisfy: 4.7<FOV / CRA<5.9. Satisfying the above range helps the incident light of different field angles of the optical lens to be incident on the image sensor at a suitable angle, which helps to improve the photosensitive performance of the image sensor, and further improves the imaging quality of the optical lens.

[0052] In some embodiments, the object-side half-aperture sag of the seventh lens SAG71 and the center thickness of the seventh lens CT7 satisfy: 0.01≤SAG71 / CT7≤0.21. 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, ensuring that the seventh lens has good assembly stability.

[0053] In some embodiments, the object-side half-aperture of the first lens CSD11 and the object-side half-aperture of the eighth lens CSD81 satisfy: 0.6<CSD11 / CSD81<1. Satisfying the above range makes the optical lens have a larger aperture, which can better realize large-angle light collection, realize large-wide-angle imaging of the optical lens, and at the same time, can increase the imaging area of the optical lens, and realize large-target imaging of the optical lens.

[0054] In some embodiments, the object-side curvature radius of the first lens R1 and the object-side half-aperture sag of the first lens SAG11 satisfy: 11<R1 / SAG11<20. Satisfying the above range reasonably controls the ratio between the object-side curvature radius of the first lens and the sag at the maximum effective aperture, provides negative refractive power for the optical lens, thereby capturing light rays with large angles entering the optical lens, expanding the field of view angle range of the optical lens, and realizing large field of view angle characteristics of the optical lens.

[0055] In some embodiments, the optical lens satisfies the following conditional expressions: 4.1mm < f < 4.3mm; 105° < FOV < 115°; 1.9mm ≤ EPDI < 2.3mm; 13mm < TTL < 19mm; 1.8 < Fno < 2.2; 11.5mm ≤ IH ≤ 12mm. In the above conditional expressions, f represents the effective focal length of the optical lens, FOV represents the maximum field of view angle of the optical lens, 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, and IH represents the real image height corresponding to the maximum field of view angle of the optical lens. Satisfying the above ranges, the optical 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.

[0056] 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 the glass-plastic hybrid structure can effectively reduce the cost, correct the aberration, reduce the volume, improve the thermal stability, and provide an optical lens product with higher performance-price ratio.

[0057] 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 the spherical structure, the aspherical structure can effectively reduce the aberration of the optical system, thereby reducing the number of lenses and the size of the lenses, and better achieving lens miniaturization. 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.

[0058] 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 from the vertex of the curved surface in the direction of the optical axis, h is the distance from the optical axis to the curved surface, c is the curvature of the vertex of the curved surface, K is the quadratic surface coefficient, and B, C, D, E, F, G, and H are the fourth-order, sixth-order, eighth-order, tenth-order, twelfth-order, fourteenth-order, and sixteenth-order surface coefficients, respectively.

[0059] The application will be further described in the following embodiments. In each embodiment, the thickness, the radius of curvature, 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 only the preferred embodiments of the application, but the embodiments of the application are not limited to the following embodiments only, any changes, substitutions, combinations or simplifications made without departing from the innovative points of the application should be regarded as equivalent replacement, and are included in the protection scope of the application.

[0060] Embodiment 1 Please refer to Figure 1 , which is a structural schematic diagram of the optical lens 100 provided in the embodiment 1 of the application, the optical lens 100 includes, along the optical axis from the object side to the imaging surface, 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.

[0061] The first lens L1 has a negative focal power, the object side surface S1 is a convex surface, and the image side surface S2 is a concave surface; The second lens L2 has a positive focal power, the object side surface S3 is a convex surface at the near optical axis, and the image side surface S4 is a convex surface; The third lens L3 has a positive focal power, the object side surface S5 is a convex surface, and the image side surface S6 is a convex surface; The fourth lens L4 has a positive focal power, the object side surface S7 is a convex surface, and the image side surface S8 is a convex surface; The fifth lens L5 has a negative focal power, the object side surface S9 is a convex surface at the near optical axis, and the image side surface S10 is a concave surface; The sixth lens L6 has a negative focal power, the object side surface S11 is a concave surface at the near optical axis, and the image side surface S12 is a concave surface at the near optical axis; The seventh lens L7 has a positive focal power, the object side surface S13 is a convex surface, and the image side surface S14 is a convex surface; The eighth lens L8 has a negative focal power, the object side surface S15 is a convex surface at the near optical axis, and the image side surface S16 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.

[0062] The third lens L3 is a glass aspheric 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 all plastic aspheric lenses.

[0063] The related parameters of each lens in the optical lens 100 in the embodiment 1 are shown in Table 1-1.

[0064] Table 1-1 The surface shape parameters of the aspherical lenses of the optical lens 100 in Example 1 are shown in Table 1-2.

[0065] 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 .

[0066] Figure 2 The F-Tan(Theta) distortion curve of Example 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-6%~2%, which shows that the optical lens 100 can better correct the distortion.

[0067] Figure 3 The field curvature curve of Example 1 is shown, which represents the curvature of the meridional image surface and the sagittal image surface of light rays of different wavelengths, 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.

[0068] Figure 4 The axial chromatic aberration curve of Example 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-4μm~6μm, 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.

[0069] Example 2 Please refer to Figure 5 , which is a structural schematic diagram of the optical lens 200 provided in Example 2 of the present application. Compared with Example 1, the main difference is that the object side S3 of the second lens L2 is concave near the optical axis; the object side S7 of the fourth lens L4 is concave; the image side S12 of the sixth lens L6 is convex near the optical axis; and the optical parameters such as the curvature radius and the lens thickness of each lens surface are different.

[0070] The related parameters of each lens in the optical lens 200 in Embodiment 2 are shown in Table 2-1.

[0071] Table 2-1 The surface profile parameters of the aspheric lens of the optical lens 200 in Embodiment 2 are shown in Table 2-2.

[0072] Table 2-2 In the present embodiment, the F-Tan(Theta) distortion curve, the field curvature curve and the axial chromatic aberration curve of the optical lens 200 are shown in Figure 6 、 Figure 7 、 Figure 8

[0073] As can be seen from Figure 6 , the distortion of the optical lens is controlled within ±5%, which indicates that the optical lens 200 can well correct the distortion.

[0074] As can be seen from Figure 7 , the field curvature of the meridional image surface and the sagittal image surface is controlled within -0.15mm~0.1mm, which indicates that the optical lens 200 can well correct the field curvature.

[0075] As can be seen from Figure 8 , the axial chromatic aberration of the longest wavelength and the shortest wavelength is controlled within -2μm~5μm, which indicates that the optical lens can well correct the chromatic aberration of the edge field of view and the secondary spectrum of the entire image surface.

[0076] Embodiment 3 Please refer to Figure 9 , which is a structural schematic diagram of the optical lens 300 provided in Embodiment 3 of the present application. Compared with Embodiment 1, the main difference is that the object side S3 of the second lens L2 is a concave surface near the optical axis; the image side S12 of the sixth lens L6 is a convex surface near the optical axis; and the optical parameters such as the curvature radius and the lens thickness of each lens surface are different.

[0077] The related parameters of each lens in the optical lens 300 in Embodiment 3 are shown in Table 3-1.

[0078] Table 3-1 The surface profile parameters of the aspheric lens of the optical lens 300 in Embodiment 3 are shown in Table 3-2.

[0079] Table 3-2 ​In this embodiment, the F-Tan (Theta) distortion curve, field curvature curve, and transverse chromatic aberration curve of the optical lens 300 are as follows: Figure 10 , Figure 11 , Figure 12 As shown.

[0080] from Figure 10 As can be seen, the distortion of the optical lens is controlled within -6% to 2%, indicating that the optical lens 300 can correct distortion well.

[0081] from Figure 11 As can be seen, the field curvature of the meridional and sagittal image planes is controlled within -0.1mm to 0.05mm, indicating that the optical lens 300 can effectively correct field curvature.

[0082] from Figure 12 As can be seen, the transverse chromatic aberration of the longest and shortest wavelengths is controlled within -2μm to 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.

[0083] 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, principal ray incident angle CRA at the maximum image height, true image height IH corresponding to the maximum field of view, maximum field of view FOV, entrance pupil diameter EPDI, and the values ​​corresponding to each conditional expression in each embodiment.

[0084] Table 4 In summary, the optical lens provided by the present invention employs 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. This allows the lens to possess one or more of the following advantages: large field of view, large entrance diameter, short overall length, large aperture, large image plane, low distortion, and low sensitivity.

[0085] 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.

[0086] The above embodiments only express several implementation manners of the present application, and the description is more specific and detailed, but it should not be understood as a limitation on the patent scope of the present application. It should be noted that for ordinary skilled persons in the art, without departing from the concept of the present application, several modifications and improvements can be made, 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 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 negative refractive power, the object side surface of which is concave at the near optical axis; a seventh lens with positive refractive power, the object side surface of which is convex, 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 total track length TTL of the optical lens and the real image height IH corresponding to the maximum field angle of the optical lens satisfy: 1.1 < TTL / IH < 1.

6.

2. The optical lens of claim 1, wherein, The real image height IH corresponding to the maximum field angle of the optical lens and the entrance pupil diameter EPDI of the optical lens satisfy: 5.2 < IH / EPDI < 6.

2.

3. The optical lens of claim 1, wherein, The effective focal length f of the optical lens and the aperture value Fno of the optical lens satisfy: 1.8 mm < f / Fno < 2.3 mm.

4. 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 < -1.3; 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.

5. 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: 5 < f2 / f < 13.

6. 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: 1.1 < f3 / f < 2.

3.

7. 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: 2.1 < f4 / f < 9.7; the image side surface curvature radius R8 of the fourth lens and the focal length f4 of the fourth lens satisfy: -1.2 < R8 / f4 < -0.

5.

8. The optical lens of claim 1, wherein, The focal length f5 of the fifth lens and the effective focal length f of the optical lens satisfy: -2.4 < f5 / f < -1.9; the distance CT56 of the fifth lens and the sixth lens on the optical axis and the focal length f5 of the fifth lens satisfy: -0.2 ≤ CT56 / f5 ≤ -0.

1.

9. 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: 0.6 < f7 / f < 1.

4.

10. The optical lens of claim 1, wherein, The focal length f8 of the eighth lens and the effective focal length f of the optical lens satisfy: -2 < f8 / f < -1; the object side surface curvature radius R15 of the eighth lens and the image side surface curvature radius R16 of the eighth lens satisfy: 0.4 < (R15-R16) / (R15+R16) < 0.

6.

11. The optical lens of claim 1, wherein, An object-side half-sagittal radius of the eighth lens SAG81, an image-side half-sagittal radius of the eighth lens SAG82, and a central thickness CT8 of the eighth lens satisfy: -1.5 ≤ (SAG81 + SAG82) / CT8 ≤ -0.7.

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