Optical lens

Abstract

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

Description

Technical Field

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

[0002] With the rapid development of electronic product performance and technology, the resolution of video conferencing equipment has been continuously improving, evolving from the common 1080P to 4K and even higher, while also placing higher demands on image distortion control. Currently, mainstream video conferencing lenses use a sensor surface smaller than 1 / 2 inch, with an all-glass or all-plastic structure. This results in either excessively high costs and bulky size, or poor heat resistance leading to defocusing and blurry images. Therefore, there is a need to develop an optical lens with one or more advantages such as high resolution, low cost, small size, and low distortion to better meet market demands. Summary of the Invention

[0003] To address the aforementioned problems, the present invention aims to provide an optical lens with the advantage of excellent image quality.

[0004] The technical solution adopted in this invention is as follows:

[0005] An optical lens comprises eight lenses with optical power, arranged sequentially along the optical axis from the object side to the imaging plane:

[0006] The first lens with negative optical power has a convex object side and a concave image side.

[0007] A second lens with positive optical power has a convex image-side surface.

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

[0009] The fourth lens has positive optical power and its image-side surface is convex.

[0010] The fifth lens with negative optical power has a convex object-side surface near the optical axis and a concave image-side surface.

[0011] The sixth lens, which has negative optical power, has a concave object-side surface near the optical axis.

[0012] The seventh lens with positive optical power has a convex object-side surface and a convex image-side surface.

[0013] The eighth lens with negative optical power has an object-side surface that is convex near the optical axis and an image-side surface that is concave near the optical axis.

[0014] Wherein, the total optical length TTL of the optical lens and the true image height IH corresponding to the maximum field of view of the optical lens satisfy: 1.1 <TTL / IH<1.6。

[0015] Further preferably, the true 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.

[0016] Further preferably, the effective focal length f of the optical lens and the f-number Fno of the optical lens satisfy: 1.8 mm < f / Fno < 2.3 mm.

[0017] 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 < -1.3; the focal length f1 of the first lens, the curvature radius R1 of the object side surface of the first lens, and the curvature radius R2 of the image side surface of the first lens satisfy: -0.4 < f1 / (R1 + R2) < -0.3.

[0018] Further preferably, the focal length f2 of the second lens and the effective focal length f of the optical lens satisfy: 5 < f2 / f < 13.

[0019] Further preferably, 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.

[0020] Further preferably, 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 curvature radius R8 of the image side surface of the fourth lens and the focal length f4 of the fourth lens satisfy: -1.2 < R8 / f4 < -0.5.

[0021] Further preferably, 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 on the optical axis between the fifth lens and the sixth lens and the focal length f5 of the fifth lens satisfy: -0.2 ≤ CT56 / f5 ≤ -0.1.

[0022] Further preferably, 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.

[0023] Further preferably, the focal length f8 of the eighth lens and the effective focal length f of the optical lens satisfy: -2 < f8 / f < -1; the curvature radius R15 of the object side surface of the eighth lens and the curvature radius R16 of the image side surface of the eighth lens satisfy: 0.4 < (R15 - R16) / (R15 + R16) < 0.6.

[0024] Further preferably, the object-side half-aperture height SAG81 of the eighth lens, the image-side half-aperture height SAG82 of the eighth lens, and the center thickness CT8 of the eighth lens satisfy: -1.5≤(SAG81+SAG82) / CT8≤-0.7.

[0025] 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. This gives the lens one or more advantages such as a large field of view, a large entrance diameter, a short overall length, a large aperture, a large image plane, low distortion, and low sensitivity. Attached Figure Description

[0026] 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:

[0027] Figure 1 This is a schematic diagram of the optical lens in Embodiment 1 of the present invention.

[0028] Figure 2 This is an F-Tan (Theta) distortion curve of the optical lens in Embodiment 1 of the present invention.

[0029] Figure 3 This is a field curvature curve diagram of the optical lens in Embodiment 1 of the present invention.

[0030] Figure 4 This is a chromatic aberration curve of the optical lens in Embodiment 1 of the present invention.

[0031] Figure 5 This is a schematic diagram of the optical lens structure in Embodiment 2 of the present invention.

[0032] Figure 6 This is an F-Tan (Theta) distortion curve of the optical lens in Embodiment 2 of the present invention.

[0033] Figure 7 This is a field curvature curve diagram of the optical lens in Embodiment 2 of the present invention.

[0034] Figure 8 This is a chromatic aberration curve of the optical lens in Embodiment 2 of the present invention.

[0035] Figure 9 This is a schematic diagram of the optical lens in Embodiment 3 of the present invention.

[0036] Figure 10 This is an F-Tan (Theta) distortion curve of the optical lens in Embodiment 3 of the present invention.

[0037] Figure 11 This is a field curvature curve diagram of the optical lens in Embodiment 3 of the present invention.

[0038] Figure 12 This is a chromatic aberration curve of the optical lens in Embodiment 3 of the present invention.

[0039] The following detailed description, in conjunction with the accompanying drawings, will further illustrate the present invention. Detailed Implementation

[0040] 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.

[0041] 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.

[0042] 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.

[0043] 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.

[0044] 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.

[0045] Unless otherwise defined, 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 (such as those defined in a common dictionary) shall be interpreted as having a meaning 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.

[0046] It should be noted that, without conflict, the embodiments in this application and the features in the embodiments may be combined with each other. The following will describe this application in detail with reference to the drawings and in combination with the embodiments.

[0047] The optical lens provided by an embodiment of the present invention includes eight lenses with optical power, which are, in order from the object side to the imaging surface along the optical axis, a first lens, a second lens, a third lens, a fourth lens, a fifth lens, a sixth lens, a seventh lens, and an eighth lens.

[0048] In some embodiments, the first lens may have negative optical power, its object side may be convex, and its image side may be concave. The second lens may have positive optical power, its object side may be convex or concave near the optical axis, and its image side may be convex. The third lens may have positive optical power, its object side may be convex, and its image side may be convex. The fourth lens may have positive optical power, its object side may be convex or concave, and its image side may be convex. The fifth lens may have negative optical power, its object side may be convex near the optical axis, and its image side may be concave. The sixth lens may have negative optical power, its object side may be concave near the optical axis, and its image side may be concave or convex near the optical axis. The seventh lens may have positive optical power, its object side may be convex, and its image side may be convex. The eighth lens may have negative optical power, its object side may be convex near the optical axis, and its image side may be concave near the optical axis.

[0049] In some embodiments, the optical lens may further include an aperture stop, which may be located between the second lens and the third lens. It can be understood that the aperture stop is used to limit the amount of incident light to change the brightness of the image formation.

[0050] In some embodiments, the optical lens may further include a filter, which is disposed along the optical axis between the eighth lens and the imaging surface. The filter is used to filter out interfering light to prevent the interfering light from reaching the imaging surface of the optical lens and affecting normal image formation.

[0051] In some embodiments, the total optical length TTL of the optical lens and the true image height IH corresponding to the maximum field angle of view of the optical lens satisfy: 1.1 < TTL / IH < 1.6. Meeting the above range can ensure that the optical lens has high pixels while effectively shortening the total optical length of the optical lens, enabling the optical lens to meet miniaturization requirements while having relatively high imaging quality.

[0052] In some embodiments, the true 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. Meeting the above range, while the optical lens has a large image plane, it has a relatively large entrance pupil diameter and a relatively high light transmittance, thereby improving the imaging effect when the optical lens works in a dark environment, and reducing the aberration of the edge field of view.

[0053] In some embodiments, the effective focal length f of the optical lens and the f-number Fno of the optical lens satisfy: 1.8 mm < f / Fno < 2.3 mm. Meeting the above range is conducive to the optical lens obtaining the characteristic of a large aperture, enabling the optical lens to have sufficient light input, so that the captured images are clearer. At the same time, the problem of shooting in low light is solved through a large aperture, and the sense of layering of the picture is enhanced by flexible depth-of-field control.

[0054] In some embodiments, 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 curvature radius R1 of the object side surface of the first lens, and the curvature radius R2 of the image side surface of the first lens satisfy: -0.4 < f1 / (R1 + R2) < -0.3. Meeting the above range, it is defined that the first lens has a negative optical power, which can capture the light rays entering the optical lens at a large angle, expanding the field angle range of the optical lens. At the same time, it is beneficial to reduce the sensitivity of the optical lens and achieve a miniaturized design. At the same time, reasonably setting 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 of the optical lens, so as to balance the astigmatism problem brought by the large field angle, so that the astigmatism of the optical lens is not too large while having a large field of view, thereby ensuring that the optical lens has excellent imaging quality.

[0055] In some embodiments, the focal length f2 of the second lens and the effective focal length f of the optical lens satisfy: 5 < f2 / f < 13. Meeting the above range, in cooperation with the first lens, it enables light rays at a large angle to enter the optical lens, thereby expanding the field angle of the optical lens. At the same time, it is beneficial to correct astigmatism and chromatic aberration and improve the imaging quality of the optical lens.

[0056] In some embodiments, 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. Meeting the above range, it is defined that the third lens has a positive optical power and defines the proportion of the optical power of the third lens, which is beneficial to adjusting the light ray trend from the first lens and the second lens, enabling the optical lens to have certain characteristics of a large field angle, low sensitivity and miniaturization.

[0057] 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 curvature radius R8 of the fourth lens and the focal length f4 of the fourth lens satisfy: -1.2 < R8 / f4 < -0.5. Meeting the above ranges, by setting the fourth lens to have a large positive refractive power, the aberration of the peripheral field of view can be effectively improved, and the overall imaging quality of the optical lens can be enhanced. At the same time, reasonably limiting the optical power and the surface shape of the image side of the fourth lens is beneficial to converging light while reducing the deflection angle of the light, shortening the distance for the light to reach the next lens, and is beneficial to reducing the total length of the lens.

[0058] 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 spacing 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. Meeting the above ranges, the fifth lens has a certain negative optical power, which can expand the width of the incident light beam exiting the optical lens, facilitating the photosensitive element to receive the light carrying image information with the largest area, and ensuring the high-pixel imaging quality of the optical lens. At the same time, on the basis of achieving miniaturization of the optical lens, the optical lens can have the characteristic of a certain back focal length, reducing the assembly interference between the optical lens and the imaging chip, and can also make the total length of the optical lens shorter and the structure more compact.

[0059] 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. Meeting the above ranges, the positive refractive power intensity provided by the seventh lens for the optical lens can better constrain the rear-end light, thereby effectively correcting chromatic aberration. At the same time, as the lens at the rear-end position in the optical lens, the seventh lens can better correct the aberration generated by the decentration difference of each lens on the object side, that is, it can reduce the decentration sensitivity of the optical lens, suppress the astigmatism generated by the decentration of each lens on the object side, and thus achieve the correction of the aberration of the optical lens and improve the imaging resolution.

[0060] 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 curvature radius R15 of the eighth lens and the image-side curvature radius R16 of the eighth lens satisfy: 0.4 < (R15 - R16) / (R15 + R16) < 0.6. Meeting the above ranges, limiting the eighth lens to have a negative optical power is beneficial to expanding the width of the light beam, enabling the width of the light beam at a larger angle to expand after passing through the first lens to the seventh lens, allowing the wide light beam to fully enter the imaging surface of the optical lens, meeting large-format imaging, and being beneficial to achieving high-pixel imaging. At the same time, reasonably limiting the surface shape of the eighth lens can correct the aberration generated by the previous lens, which is beneficial to improving the imaging quality of the optical lens and reducing the forming difficulty of the eighth lens.

[0061] In some embodiments, the sagittal height SAG81 of the clear aperture semi-diameter on the object side of the eighth lens, the sagittal height SAG82 of the clear aperture semi-diameter on the image side of the eighth lens, and the central thickness CT8 of the eighth lens satisfy: -1.5 ≤ (SAG81 + SAG82) / CT8 ≤ -0.7. Meeting the above range is beneficial to controlling the refractive power and thickness at various positions of the eighth lens in the direction perpendicular to the optical axis, avoiding the eighth lens being too thick or too thin, reducing the incident angle of light on the object side of the eighth lens, and reducing the tolerance sensitivity of the optical lens. At the same time, the eighth lens has multiple inflection points, which is beneficial to correcting the distortion and field curvature generated by the lens on the object side of the eighth lens, and evenly distributing the refractive power of multiple lenses on the imaging surface close to the optical lens.

[0062] In some embodiments, the maximum field angle 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. Meeting the above range, the incident light rays at different field angles of the optical lens can all enter the image sensor at an appropriate angle, which is beneficial to improving the photosensitive performance of the image sensor and thus improving the imaging quality of the optical lens.

[0063] In some embodiments, the sagittal height SAG71 of the clear aperture semi-diameter on the object side of the seventh lens and the central thickness CT7 of the seventh lens satisfy: 0.01 ≤ SAG71 / CT7 ≤ 0.21. Meeting 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 good assembly stability of the seventh lens.

[0064] In some embodiments, the clear aperture semi-diameter CSD11 on the object side of the first lens and the clear aperture semi-diameter CSD81 on the object side of the eighth lens satisfy: 0.6 < CSD11 / CSD81 < 1. Meeting the above range enables the optical lens to have a larger aperture, better collect light rays at large angles, achieve large-angle imaging of the optical lens, and at the same time increase the imaging area of the optical lens to achieve large-target imaging of the optical lens.

[0065] In some embodiments, the radius of curvature R1 of the object side of the first lens and the sagittal height SAG11 of the clear aperture semi-diameter on the object side of the first lens satisfy: 11 < R1 / SAG11 < 20. Meeting the above range reasonably controls the ratio relationship between the radius of curvature of the object side of the first lens and the sagittal height at the maximum effective aperture, provides negative refractive power for the optical lens, thereby capturing the light rays entering the optical lens at large angles, expanding the field angle range of the optical lens, and achieving the large-field angle characteristic of the optical lens.

[0066] In some embodiments, the optical lens satisfies the following conditional expressions: 4.1 mm < f < 4.3 mm; 105° < FOV < 115°; 1.9 mm ≤ EPDI < 2.3 mm; 13 mm < TTL < 19 mm; 1.8 < Fno < 2.2; 11.5 mm < IH ≤ 12 mm. In the above conditional expressions, f represents the effective focal length of the optical lens, FOV represents the maximum field 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 true image height corresponding to the maximum field angle of the optical lens. Meeting the above ranges, the optical lens has at least one or more advantages such as a large field angle, a large entrance pupil diameter, a short total length, a large aperture, a large image plane, small distortion, and low sensitivity characteristics.

[0067] In some embodiments, the lens material of 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. Additionally, when the lens material is glass, due to the low dispersion characteristic of glass itself, the geometric chromatic aberration of the optical system can be effectively corrected. The third lens in the optical lens provided by the present invention can adopt a glass material, and the first lens, the second lens, the fourth lens, the fifth lens, the sixth lens, the seventh lens, and the eighth lens can adopt plastic materials. Adopting a glass-plastic hybrid structure can effectively reduce costs, correct aberrations, reduce the volume, improve the thermal stability performance, and provide an optical lens product with higher cost performance.

[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 adopt spherical lenses or aspherical lenses. Compared with the spherical structure, the aspherical structure can effectively reduce the aberration of the optical system, thereby reducing the number of lenses and the size of the lenses, and better realizing the 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 of the present invention all adopt aspherical lenses.

[0069] In various embodiments of the present invention, when the lens adopts an aspherical lens, the shapes of the aspherical surfaces of the optical lens satisfy the following equations:

[0070] ;

[0071] where z is the distance between the surface and the vertex of the surface in the optical axis direction, h is the distance from the optical axis to the surface, c is the curvature of the vertex of the surface, K is the conic coefficient, and B, C, D, E, F, G, H are the surface coefficients of the fourth order, sixth order, eighth order, tenth order, twelfth order, fourteenth order, and sixteenth order respectively.

[0072] 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.

[0073] Example 1

[0074] Please see Figure 1 The diagram shows a schematic of the structure of the optical lens 100 provided in Embodiment 1 of the present invention. The optical lens 100 includes, along the optical axis from the object side to the imaging plane, the following components in sequence: a first lens L1, a second lens L2, an aperture ST, a third lens L3, a fourth lens L4, a fifth lens L5, a sixth lens L6, a seventh lens L7, an eighth lens L8, and a filter G1.

[0075] Among them, the first lens L1 has negative optical power, its object side S1 is convex, and its image side S2 is concave.

[0076] The second lens L2 has positive optical power, its object side S3 is convex near the optical axis, and its image side S4 is convex.

[0077] The third lens L3 has positive optical power, its object side S5 is convex, and its image side S6 is convex.

[0078] The fourth lens L4 has positive optical power, its object side S7 is convex, and its image side S8 is convex.

[0079] The fifth lens L5 has negative optical power, its object side S9 is convex near the optical axis, and its image side S10 is concave.

[0080] The sixth lens L6 has negative optical power, its object side S11 is concave near the optical axis, and its image side S12 is concave near the optical axis.

[0081] The seventh lens L7 has positive optical power, its object side S13 is convex, and its image side S14 is convex.

[0082] The eighth lens L8 has negative optical power, its object side S15 is convex near the optical axis, and its image side S16 is concave near the optical axis.

[0083] The object-side surface S17 and the image-side surface S18 of filter G1 are both planar.

[0084] The imaging plane S19 is a plane.

[0085] The third lens L3 is a glass aspherical lens, while 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 aspherical lenses.

[0086] The relevant parameters of each lens in the optical lens 100 in Example 1 are shown in Table 1-1.

[0087] Table 1-1

[0088]

[0089] The surface profile parameters of the aspherical lens of the optical lens 100 in Example 1 are shown in Table 1-2.

[0090] Table 1-2

[0091]

[0092] In this embodiment, the F-Tan (Theta) distortion curve, field curvature curve, and transverse chromatic aberration curve of the optical lens 100 are as follows: Figure 2 , Figure 3 , Figure 4 As shown.

[0093] Figure 2 The F-Tan (Theta) distortion curve of Example 1 is shown, which represents the distortion of light 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 of view (unit: °). As can be seen from the figure, the distortion of the optical lens is controlled within -6% to 2%, indicating that the optical lens 100 can correct distortion well.

[0094] Figure 3 The field curvature curve of Embodiment 1 is shown, which represents the degree of curvature of light of different wavelengths in the meridional and sagittal image planes. The horizontal axis represents the offset (unit: mm), and the vertical axis represents the half field of view (unit: °). As can be seen from the figure, the field curvature of the meridional and sagittal image planes is controlled within ±0.05 mm, indicating that the optical lens 100 can effectively correct the field curvature.

[0095] 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 (0.555 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 -4 μm to 6 μm, indicating that the optical lens can excellently correct chromatic aberration at the edge of the field of view and the secondary spectrum of the entire image plane.

[0096] Example 2

[0097] Please see Figure 5 The figure shows 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 S3 of the second lens L2 is concave near the optical axis; the object side surface S7 of the fourth lens L4 is concave; the image side surface S12 of the sixth lens L6 is convex near the optical axis; and the optical parameters such as the radius of curvature and lens thickness of each lens surface are different.

[0098] The relevant parameters of each lens in the optical lens 200 in Example 2 are shown in Table 2-1.

[0099] Table 2-1

[0100]

[0101] The surface profile parameters of the aspherical lens of the optical lens 200 in Example 2 are shown in Table 2-2.

[0102] Table 2-2

[0103]

[0104] 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.

[0105] from Figure 6 As can be seen, the distortion of the optical lens is controlled within ±5%, indicating that the optical lens 200 can correct distortion well.

[0106] from Figure 7 As can be seen, the field curvature of the meridional and sagittal image planes is controlled within -0.15mm to 0.1mm, indicating that the optical lens 200 can effectively correct field curvature.

[0107] from Figure 8 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.

[0108] Example 3

[0109] Please see Figure 9The 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 S3 of the second lens L2 is concave near the optical axis; the image side surface S12 of the sixth lens L6 is convex near the optical axis; and the optical parameters such as the radius of curvature and lens thickness of each lens surface are different.

[0110] The relevant parameters of each lens in the optical lens 300 in Example 3 are shown in Table 3-1.

[0111] Table 3-1

[0112]

[0113] The surface profile parameters of the aspherical lens of the optical lens 300 in Example 3 are shown in Table 3-2.

[0114] Table 3-2

[0115]

[0116] 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.

[0117] 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.

[0118] 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.

[0119] 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.

[0120] 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.

[0121] Table 4

[0122]

[0123] 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.

[0124] 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.

[0125] 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, 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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