Optical lens

Abstract

The application provides an optical lens, which comprises eight lenses with optical power, and sequentially comprises, along an optical axis from an object side to an imaging surface: a first lens with negative optical power, the object side being a convex surface and the image side being a concave surface; a second lens with positive optical power, the object side being a concave surface and the image side being a convex surface; a third lens with positive optical power, the object side being a convex surface and the image side being a convex surface; a fourth lens with positive optical power, the image side being a convex surface; a fifth lens with negative optical power, the object side being a convex surface at a near optical axis and the image side being a concave surface; a sixth lens with positive optical power, the image side being a convex surface; a seventh lens with positive optical power, the object side being a convex surface at a near optical axis and the image side being a convex surface; and an eighth lens with negative optical power, the object side being a convex surface at a near optical axis and the image side being a concave surface at a near optical axis. The optical lens provided by the application has one or more advantages of 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 concave object side and a convex image side.

[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 has positive optical power and its image-side surface is convex.

[0012] The seventh lens with positive optical power has an object-side surface that is convex near the optical axis and an image-side surface that is convex.

[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] Among them, the true 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; 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.

[0015] Further preferably, the effective focal length f of the optical lens, the aperture value Fno of the optical lens, and the overall optical length TTL of the optical lens satisfy: 0.4 < f×Fno / TTL < 0.75.

[0016] 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 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.

[0017] 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 curvature radius R3 of the object side surface of the second lens and the curvature radius R4 of the image side surface of the second lens satisfy: 4 < (R3 + R4) / (R3 - R4) < 6.9.

[0018] 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 curvature radius 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.

[0019] 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 curvature radius 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.

[0020] 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 curvature radius R12 of the image side surface of the sixth lens and the effective focal length f of the optical lens satisfy: -5.8 < R12 / f < -2.

[0021] 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 curvature radius R14 of the image side surface of the seventh lens and the effective focal length f of the optical lens satisfy: -3.6 < R14 / f < -1.3.

[0022] More 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.

[0023] Further preferably, the object-side light-transmitting half-aperture height SAG81 of the eighth lens, the image-side light-transmitting half-aperture height SAG82 of the eighth lens, and the center thickness CT8 of the eighth lens satisfy: -1.8 < (SAG81 + SAG82) / CT8 < -0.8.

[0024] 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

[0025] 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:

[0026] Figure 1 This is a schematic diagram of the optical lens structure in Embodiment 1 of the present invention.

[0027] Figure 2 This is an F-Tan (Theta) distortion curve of the optical lens in Embodiment 1 of the present invention.

[0028] Figure 3 This is a field curvature curve diagram of the optical lens in Embodiment 1 of the present invention.

[0029] Figure 4 This is a chromatic aberration curve of the optical lens in Embodiment 1 of the present invention.

[0030] Figure 5 This is a schematic diagram of the optical lens structure in Embodiment 2 of the present invention.

[0031] Figure 6 This is an F-Tan (Theta) distortion curve of the optical lens in Embodiment 2 of the present invention.

[0032] Figure 7 This is a field curvature curve diagram of the optical lens in Embodiment 2 of the present invention.

[0033] Figure 8 This is a chromatic aberration curve of the optical lens in Embodiment 2 of the present invention.

[0034] Figure 9 This is a schematic diagram of the optical lens in Embodiment 3 of the present invention.

[0035] Figure 10 This is an F-Tan (Theta) distortion curve of the optical lens in Embodiment 3 of the present invention.

[0036] Figure 11 This is a field curvature curve diagram of the optical lens in Embodiment 3 of the present invention.

[0037] Figure 12 This is a chromatic aberration curve of the optical lens in Embodiment 3 of the present invention.

[0038] The following detailed description, in conjunction with the accompanying drawings, will further illustrate the present invention. Detailed Implementation

[0039] 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.

[0040] 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.

[0041] 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.

[0042] 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.

[0043] 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.

[0044] Unless otherwise specified, all terms used herein (including technical and scientific terms) shall have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains. It should also be understood that terms (e.g., those defined in common dictionaries) shall be interpreted as having the meaning consistent with their meaning in the context of the relevant art and shall not be interpreted in an idealized or overly formal sense unless expressly so specified herein.

[0045] It should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other. This application will now be described in detail with reference to the accompanying drawings and embodiments.

[0046] The optical lens provided in this embodiment of the invention includes eight lenses with optical power, which are arranged sequentially from the object side to the imaging plane along the optical axis as a first lens, a second lens, a third lens, a fourth lens, a fifth lens, a sixth lens, a seventh lens, and an eighth lens.

[0047] In some embodiments, the first lens may have negative optical power, its object-side surface may be convex, and its image-side surface may be concave. The second lens may have positive optical power, its object-side surface may be concave, and its image-side surface may be convex. The third lens may have positive optical power, its object-side surface may be convex, and its image-side surface may be convex. The fourth lens may have positive optical power, its object-side surface may be convex or concave, and its image-side surface may be convex. The fifth lens may have negative optical power, its object-side surface may be convex near the optical axis, and its image-side surface may be concave. The sixth lens may have positive optical power, its object-side surface may be concave or convex near the optical axis, and its image-side surface may be convex. The seventh lens may have positive optical power, its object-side surface may be convex near the optical axis, and its image-side surface may be convex. The eighth lens may have negative optical power, its object-side surface may be convex near the optical axis, and its image-side surface may be concave near the optical axis.

[0048] In some embodiments, the optical lens may also include an aperture stop, which may be located between the second lens and the third lens. It is understood that the aperture stop is used to limit the amount of light entering the lens, thereby altering the brightness of the image.

[0049] In some embodiments, the optical lens may further include a filter disposed between the eighth lens and the imaging surface along the optical axis. The filter is used to filter out interfering light and prevent the interfering light from reaching the imaging surface of the optical lens and affecting normal imaging.

[0050] In some embodiments, the true 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; 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. Meeting the above ranges, shortening the effective focal length can expand the field angle, enabling the optical lens to capture a wider object-side space, while enabling the optical lens to match a chip with a large image surface and improving the imaging quality of the optical lens. At the same time, controlling the ratio of the effective focal length to the entrance pupil diameter of the optical lens helps to improve the light-receiving ability of the optical lens, obtain as much object-side information as possible, and thus obtain imaging information with higher brightness and resolution.

[0051] In some embodiments, 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. Meeting the above ranges, the optical lens satisfies the characteristics of a short focal length with a large aperture, allowing the optical lens to have sufficient light input, enabling the optical lens to have a large wide-angle field of view to capture more scene information, and using flexible depth-of-field control to enhance the sense of hierarchy of the picture, which is beneficial for the captured image to be clearer. At the same time, the limitation of the total optical length enables the optical lens to meet the miniaturization requirement.

[0052] 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 < -1.5; 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 ranges, the first lens has a negative optical power, which can capture the light rays entering the optical lens at large angles, expand the field angle range of the optical lens, and is beneficial for reducing the sensitivity of the optical lens and realizing the miniaturized design of the optical lens. At the same time, controlling the surface shape of the first lens is beneficial for reducing the bending degree of the light rays at the image side surface of the first lens and reducing the astigmatism of the optical lens to balance the astigmatism problem brought by the large field angle of the optical lens, so that the astigmatism of the optical lens is not too large while having a large field of view, and thus ensuring that the optical lens has excellent imaging quality.

[0053] 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 curvature radius R3 of the object side surface of the second lens and the curvature radius 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 a positive optical power. Cooperating with the first lens, it enables large-angle light to enter the optical lens, which is beneficial to expanding the field angle of the optical lens, correcting the astigmatism and chromatic aberration of the optical lens, and improving the imaging quality of the optical lens. At the same time, by reasonably setting the surface shape of the second lens, the object side surface and the image side surface of the second lens can be made close to a concentric circle structure, effectively improving the astigmatism, distortion and coma of the optical lens, and further improving the imaging quality of the optical lens.

[0054] 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 curvature radius 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 a positive optical power, which is beneficial to adjusting the light path 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. At the same time, setting the object side surface shape of the third lens to be convex can make the light passing through the second lens converge into the third lens, which is beneficial to reducing the size of the subsequent lenses and contributing to the miniaturization characteristics of the optical lens. And the third lens can effectively reduce the generation of spherical aberration and astigmatism to improve the imaging quality of the optical lens.

[0055] 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 curvature radius 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 a positive optical power, which can effectively improve the aberration of the edge field of view and improve the overall imaging quality. At the same time, controlling the surface shape of the image side surface of the fourth lens can effectively correct the spherical aberration of the optical lens, reduce the influence of astigmatism on the imaging of the optical lens, and adjust the light path, enabling the optical lens to have the characteristics of a large field angle and ultra-thinness.

[0056] 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 curvature radius R12 of the sixth lens and the effective focal length f of the optical lens satisfy: -5.8 < R12 / f < -2. Meeting the above ranges, the sixth lens has a positive optical power, which can restrict the light path, is beneficial to correcting chromatic aberration, reducing the eccentricity sensitivity, correcting the system aberration, and improving the imaging resolution. At the same time, by controlling the surface shape of the image side of the sixth lens, and then controlling the light path of the marginal rays on the image side of the sixth lens, the optical lens can accept light at a larger angle, which is beneficial to reducing the distortion of the optical lens. At the same time, the turning angle of the light when it reaches the sixth lens is small, which is beneficial to reducing the tolerance sensitivity of the optical lens.

[0057] 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 curvature radius R14 of the seventh lens and the effective focal length f of the optical lens satisfy: -3.6 < R14 / f < -1.3. Meeting the above ranges, the positive refractive power provided by the seventh lens for the optical lens can better constrain the rear-end light, effectively correct chromatic aberration. At the same time, as a lens at the rear-end position in the optical lens, the seventh lens can better correct the aberration generated by the eccentricity difference of each lens on the object side, that is, it can reduce the eccentricity sensitivity of the optical lens, suppress the astigmatism generated by the eccentricity of each lens on the object side, and thus achieve the correction of the aberration of the optical lens and improve the imaging resolution. At the same time, by controlling the surface shape of the image side of the seventh lens, it can effectively correct the spherical aberration of the optical lens, reduce the influence of astigmatism on the imaging of the optical lens, and can also adjust the light path, enabling the optical lens to have the characteristics of a large field angle and ultra-thinness.

[0058] 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. Meeting the above ranges, by reasonably configuring 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, it is beneficial to mutually correct the aberrations generated 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 aperture to ensure a large field angle.

[0059] 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: -1.8 < (SAG81 + SAG82) / CT8 < -0.8. Meeting the above range is beneficial to controlling the refractive power and thickness of each part 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 surface 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 near the imaging surface of the optical lens.

[0060] In some embodiments, the radius of curvature R1 of the object side surface of the first lens and the sagittal height SAG11 of the clear aperture semi-diameter on the object side surface of the first lens satisfy: 11 < R1 / SAG11 < 33. Meeting the above range can reasonably control the ratio relationship between the radius of curvature of the object side surface of the first lens and the sagittal height at the maximum effective aperture, provide a 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 realizing the large field angle characteristic of the optical lens.

[0061] 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 < -1.7. Meeting the above range, the fifth lens located in the middle position has a certain negative optical power, which can expand the width of the incident light beam exiting the optical lens, is beneficial for the photosensitive element to receive the light rays carrying image information with the largest area, and ensures the high-pixel imaging quality of the optical imaging lens.

[0062] In some embodiments, the focal length f8 of the eighth lens and the effective focal length f of the optical lens satisfy: -2.8 < f8 / f < -1.3. Meeting the above range, the eighth lens has a certain negative optical power, which is beneficial for 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, realizing the large target surface imaging characteristic, and being beneficial for achieving high-pixel imaging.

[0063] In some embodiments, the sagittal height SAG71 of the clear aperture semi-diameter on the object side surface of the seventh lens and the central thickness CT7 of the seventh lens satisfy: -0.4 < SAG71 / CT7 ≤ -0.03. 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 that the seventh lens has good assembly stability.

[0064] In some embodiments, the clear aperture diameter CSD11 of the object side surface of the first lens and the clear aperture diameter CSD81 of the object side surface of the eighth lens satisfy: 0.8 < CSD11 / CSD81 < 0.95. Meeting the above range enables the optical lens to have a larger aperture, better achieve large-angle light collection, realize large-angle imaging of the optical lens, and at the same time increase the imaging area of the optical lens to achieve large-format imaging of the optical lens.

[0065] 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 overall optical length of the optical lens, Fno represents the f-number of the optical lens, IH represents the true 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. Meeting the above range, the optical lens has at least one or more advantages such as a large field angle, a large entrance pupil diameter, a short overall length, a large aperture, a large image plane, low distortion, and low sensitivity characteristics.

[0066] In some embodiments, the lens material in the optical lens provided by the present invention can be glass or plastic. When the lens material is plastic, the production cost can be effectively reduced. On the other hand, 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 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 hybrid glass-plastic 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.

[0067] 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.

[0068] In each embodiment of the present invention, when the lens adopts an aspherical lens, the surface shapes of the aspherical surfaces of the optical lens satisfy the following equation:

[0069] ;

[0070] Where z is the distance between the surface and the vertex of the surface in the direction of the optical axis, h is the distance from the optical axis to the surface, c is the curvature of the vertex of the surface, K is the quadratic surface coefficient, and B, C, D, E, F, G, and H are the fourth, sixth, eighth, tenth, twelfth, fourteenth, and sixteenth order surface coefficients, respectively.

[0071] 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.

[0072] Example 1

[0073] 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.

[0074] Among them, the first lens L1 has negative optical power, its object side S1 is convex, and its image side S2 is concave.

[0075] The second lens L2 has positive optical power, its object side S3 is concave, and its image side S4 is convex.

[0076] The third lens L3 has positive optical power, its object side S5 is convex, and its image side S6 is convex.

[0077] The fourth lens L4 has positive optical power, its object side S7 is convex, and its image side S8 is convex.

[0078] 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.

[0079] The sixth lens L6 has positive optical power, its object side S11 is concave near the optical axis, and its image side S12 is convex.

[0080] The seventh lens L7 has positive optical power, its object side S13 is convex near the optical axis, and its image side S14 is convex.

[0081] 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.

[0082] The object-side surface S17 and the image-side surface S18 of filter G1 are both planar.

[0083] The imaging plane S19 is a plane.

[0084] 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.

[0085] The relevant parameters of each lens in the optical lens 100 in Example 1 are shown in Table 1-1.

[0086] Table 1-1

[0087]

[0088] The surface profile parameters of the aspherical lens of the optical lens 100 in Example 1 are shown in Table 1-2.

[0089] Table 1-2

[0090]

[0091] 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.

[0092] 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 -8% to 2%, indicating that the optical lens 100 can correct distortion well.

[0093] 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.

[0094] Figure 4The 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 -2 μm to 5 μm, indicating that the optical lens can excellently correct chromatic aberration at the edge of the field of view and the secondary spectrum of the entire image plane.

[0095] Example 2

[0096] Please see Figure 5 The figure shown is a schematic diagram of the structure of the optical lens 200 provided in Embodiment 2 of the present invention. The main difference between this embodiment and Embodiment 1 is that the 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.

[0097] The relevant parameters of each lens in the optical lens 200 in Example 2 are shown in Table 2-1.

[0098] Table 2-1

[0099]

[0100] The surface profile parameters of the aspherical lens of the optical lens 200 in Example 2 are shown in Table 2-2.

[0101] Table 2-2

[0102]

[0103] 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.

[0104] 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.

[0105] 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.

[0106] 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.

[0107] Example 3

[0108] 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.

[0109] The relevant parameters of each lens in the optical lens 300 in Example 3 are shown in Table 3-1.

[0110] Table 3-1

[0111]

[0112] The surface profile parameters of the aspherical lens of the optical lens 300 in Example 3 are shown in Table 3-2.

[0113] Table 3-2

[0114]

[0115] 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.

[0116] from Figure 10 As can be seen, the distortion of the optical lens is controlled within -16% to 0%, indicating that the optical lens 300 can correct distortion.

[0117] from Figure 11 As can be seen, the field curvature of the meridional and sagittal image planes is controlled within ±0.05mm, indicating that the optical lens 300 can effectively correct field curvature.

[0118] from Figure 12 As can be seen, the transverse chromatic aberration of the longest and shortest wavelengths is controlled within -2μm to 4μm, 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.

[0119] 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.

[0120] Table 4

[0121]

[0122] 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.

[0123] 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.

[0124] 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 a convex surface, and the image side surface of which is a concave surface; a second lens with positive refractive power, the object side surface of which is a concave surface, and the image side surface of which is a convex surface; a third lens with positive refractive power, the object side surface of which is a convex surface, and the image side surface of which is a convex surface; a fourth lens with positive refractive power, the image side surface of which is a convex surface; a fifth lens with negative refractive power, the object side surface of which is a convex surface at the near optical axis, and the image side surface of which is a concave surface; a sixth lens with positive refractive power, the image side surface of which is a convex surface; a seventh lens with positive refractive power, the object side surface of which is a convex surface at the near optical axis, and the image side surface of which is a convex surface; an eighth lens with negative refractive power, the object side surface of which is a convex surface at the near optical axis, and the image side surface of which is a concave surface at the near optical axis; wherein a real image height IH corresponding to a maximum field angle of the optical lens and an 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 an 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, an aperture value Fno of the optical lens, and an optical total length TTL of the optical lens satisfy: 0.4<f×Fno / TTL<0.

75.

3. The optical lens of claim 1, wherein, A 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, a radius of curvature R1 of the object side surface of the first lens, and a radius of curvature R2 of the image side surface of the first lens satisfy: -0.4<f1 / (R1+R2)<-0.

3.

4. The optical lens of claim 1, wherein, A 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 a radius of curvature R3 of the object side surface of the second lens and a radius of curvature R4 of the image side surface of the second lens satisfy: 4<(R3+R4) / (R3-R4)<6.

9.

5. The optical lens of claim 1, wherein, A 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 a 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.

6. The optical lens of claim 1, wherein, A focal length f4 of the fourth lens and the effective focal length f of the optical lens satisfy: 2<f4 / f<4.1; and a 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.

7. The optical lens of claim 1, wherein, A focal length f6 of the sixth lens and the effective focal length f of the optical lens satisfy: 8<f6 / f<29; and a radius of curvature R12 of the image side surface 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, A focal length f7 of the seventh lens and the effective focal length f of the optical lens satisfy: 1.3<f7 / f<2; and a radius of curvature R14 of the image side surface 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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