Optical lens

Abstract

The present invention provides an optical lens comprising eight lenses, which, along the optical axis, from the object side to the imaging plane, comprise: a front lens group having positive optical power and a rear lens group having negative optical power; the front lens group, along the optical axis, from the object side to the imaging plane, comprises: a first lens group having negative optical power; a second lens group having negative optical power; a third lens group having positive optical power; and a fourth lens group having positive optical power; the rear lens group, along the optical axis, from the object side to the imaging plane, comprises: a fifth lens group having negative optical power; a sixth lens group having positive optical power; a seventh lens group having negative optical power; and an eighth lens group having negative optical power. The optical lens provided by the present invention, through a specific surface shape combination and a reasonable optical power distribution, can improve the imaging quality of the optical lens and has the advantage of excellent imaging quality.

Description

Technical Field

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

[0002] High-quality image transmission is crucial in modern video conferencing systems. Currently, most video conferencing lenses on the market utilize fixed-focus or variable-focus designs to meet the needs of various application scenarios. However, these traditional lenses are often bulky and heavy, which not only limits device miniaturization but also increases manufacturing costs. Therefore, there is an urgent need for an optical lens that balances miniaturization with excellent image quality to meet the needs of video conferencing. Summary of the Invention

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

[0004] The present invention provides an optical lens having eight lenses, which comprises, in order from the object side to the imaging surface along the optical axis: a front group having positive focal power and a rear group having negative focal power;

[0005] The front group includes, in order from the object side to the imaging surface along the optical axis:

[0006] The first lens has a negative optical power, its object-side surface is convex and its image-side surface is concave;

[0007] a second lens having negative optical power, whose object-side surface is concave and whose image-side surface is convex;

[0008] a third lens element having positive optical power, whose object-side surface is convex and whose image-side surface is convex;

[0009] a fourth lens element having positive optical power and a convex object-side surface;

[0010] The rear group includes, in order from the object side to the imaging surface along the optical axis:

[0011] a fifth lens element having negative optical power and a concave image-side surface;

[0012] a sixth lens element having positive refractive power, whose object-side surface is convex and whose image-side surface is convex;

[0013] a seventh lens element having negative optical power, whose object-side surface is concave and whose image-side surface is convex;

[0014] an eighth lens element having negative optical power, whose object-side surface is convex near the optical axis and whose image-side surface is concave near the optical axis;

[0015] Among them, the total optical length TTL of the optical lens and the effective focal length f of the optical lens satisfy: 2.4 < TTL / f < 3; the total optical length TTL of the optical lens and the true image height IH corresponding to the maximum field angle of the optical lens satisfy: 1.5 < TTL / IH < 1.7.

[0016] Further preferably, the combined focal length fa of the front group and the combined focal length fb of the rear group satisfy: -0.8 < fa / fb < -0.5.

[0017] Further preferably, the true image height IH corresponding to the maximum field angle of the optical lens and the aperture value Fno of the optical lens satisfy: 5.6 mm < IH / Fno < 6.1 mm.

[0018] Further preferably, the effective focal length f of the optical lens and the focal length f1 of the first lens satisfy: -25 < f1 / f < -2; the curvature radius R1 of the object side of the first lens, the curvature radius R2 of the image side of the first lens, and the central thickness CT1 of the first lens on the optical axis satisfy: 0.85 < R1 / (R2 + CT1) < l.3.

[0019] Further preferably, the effective focal length f of the optical lens and the focal length f2 of the second lens satisfy: -3.6 < f2 / f < -1.8; the curvature radius R4 of the image side of the second lens and the effective focal length f of the optical lens satisfy: -50 < R4 / f < -1.5.

[0020] Further preferably, the effective focal length f of the optical lens and the focal length f3 of the third lens satisfy: 1.3 < f3 / f < 1.8; the effective focal length f of the optical lens and the focal length f4 of the fourth lens satisfy: 0.9 < f4 / f < 1. **3**.

[0021] Further preferably, the effective focal length f of the optical lens and the focal length f5 of the fifth lens satisfy: -1.85 < f5 / f < -1.4; the effective focal length f of the optical lens and the focal length f6 of the sixth lens satisfy: 1.2 < f6 / f < 1.7.

[0022] Further preferably, the effective focal length f of the optical lens and the focal length f7 of the seventh lens satisfy: -10 < f7 / f < -6; the focal length f7 of the seventh lens and the focal length f8 of the eighth lens satisfy: 4 < f7 / f8 < 7.

[0023] Further preferably, the effective focal length f of the optical lens and the focal length f8 of the eighth lens satisfy: -1.8 < f8 / f < -1.1; the central thickness CT1 of the first lens on the optical axis and the edge thickness ET1 of the first lens satisfy: 0.8 < CT1 / ET1 < 1.

[0024] Further preferably, the object-side light-transmitting aperture DM11 of the first lens and the image-side light-transmitting aperture DM82 of the eighth lens satisfy the following conditions: 1.2 <DM11 / DM82<1.5。

[0025] Compared with the existing technology, the optical lens provided by the present invention uses eight lenses with specific optical powers. Through the combination of specific surface shapes and reasonable optical power distribution, it can improve the imaging quality of the optical lens, reduce aberrations, and improve the imaging quality of the optical lens, so that the lens has one or more advantages such as miniaturization, large aperture, large image height, and high imaging quality. BRIEF DESCRIPTION OF THE DRAWINGS

[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 with reference to the following drawings, in which:

[0027] Figure 1 Schematic diagram of the structure of the optical lens in Example 1 of the present invention.

[0028] Figure 2 4 is an astigmatism curve diagram of the optical lens in Example 1 of the present invention.

[0029] Figure 3 1 is an axial aberration curve diagram of the optical lens in Example 1 of the present invention.

[0030] Figure 4 Graph showing the vertical axis chromatic aberration of the optical lens in Example 1 of the present invention.

[0031] Figure 5 Schematic diagram of the structure of the optical lens in Example 2 of the present invention.

[0032] Figure 6 Graph showing the astigmatism of the optical lens in Example 2 of the present invention.

[0033] Figure 7 2 is an axial aberration curve diagram of the optical lens in Example 2 of the present invention.

[0034] Figure 8 Graph showing vertical axis chromatic aberration of the optical lens in Example 2 of the present invention.

[0035] Figure 9 Schematic diagram of the structure of the optical lens in Example 3 of the present invention.

[0036] Figure 10 4 is an astigmatism curve diagram of the optical lens in Example 3 of the present invention.

[0037] Figure 11 4 is an axial aberration curve diagram of the optical lens in Example 3 of the present invention.

[0038] Figure 12 Graph showing vertical axis chromatic aberration of the optical lens in Example 3 of the present invention.

[0039] Figure 13 Schematic diagram of the structure of the optical lens in Example 4 of the present invention.

[0040] Figure 14 4 is an astigmatism curve diagram of the optical lens in Example 4 of the present invention.

[0041] Figure 15 4 is an axial aberration curve diagram of the optical lens in Example 4 of the present invention.

[0042] Figure 16 Graph showing vertical axis chromatic aberration of the optical lens in Example 4 of the present invention.

[0043] The following specific embodiments will further illustrate the present invention in conjunction with the above-mentioned drawings. DETAILED DESCRIPTION

[0044] For a better understanding of the present application, various aspects of the present application will be described in more detail with reference to the accompanying drawings. It should be understood that these detailed descriptions are merely descriptions of embodiments of the present application and are not intended to limit the scope of the present 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.

[0045] It should be noted that in this specification, the terms "first," "second," "third," etc., are used solely to distinguish one feature from another and do not limit the features. Thus, the first lens discussed below could also be referred to as the second lens or the third lens without departing from the teachings of the present invention.

[0046] In the drawings, the thickness, size, and shape of the lenses are slightly exaggerated for ease of illustration. Specifically, the shapes of the spherical and aspherical surfaces shown in the drawings are provided by way of example. That is, the shapes of the spherical and aspherical surfaces are not limited to those shown in the drawings. The drawings are for illustration only and are not drawn strictly to scale.

[0047] In this article, the paraxial region refers to the area near the optical axis. If a lens surface is convex and the location of the convex surface is undefined, it means that the lens surface is convex at least in the paraxial region. If a lens surface is concave and the location of the concave surface is undefined, 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.

[0048] It should also be understood that the terms "comprises," "including," "having," "includes," and / or "comprising," when used in this specification, indicate the presence of the stated features, elements, and / or components, but do not preclude the presence or addition of one or more other features, elements, components, and / or combinations thereof. In addition, when expressions such as "at least one of..." appear after a list of listed features, they modify the entire list of features rather than modifying the individual elements in the list. In addition, when describing embodiments of the present application, "may" is used to mean "one or more embodiments of the present application." And, the term "exemplary" is intended to refer to an example or illustration.

[0049] Unless otherwise defined, all terms used herein (including technical and scientific terms) have the same meaning as commonly understood by those skilled in the art to which this application belongs. It should also be understood that terms (such as those defined in commonly used dictionaries) should be interpreted as having a meaning consistent with their meaning in the context of the relevant technology and will not be interpreted in an idealized or overly formal sense unless expressly defined as such herein.

[0050] It should be noted that, in the absence of conflict, the embodiments and features of the embodiments in this application can be combined with each other. The present application will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

[0051] The optical lens provided by the embodiment of the present invention comprises eight lenses in total, and includes, along the optical axis from the object side to the imaging plane, a front group with positive optical power and a rear group with negative optical power.

[0052] The front lens group includes, in order from the object side to the image plane along the optical axis: a first lens, a second lens, a third lens, and a fourth lens. The first lens may have negative optical power, with its object-side surface being convex and its image-side surface being concave. The second lens may have negative optical power, with its object-side surface being concave and its image-side surface being convex. The third lens may have positive optical power, with its object-side surface being convex and its image-side surface being convex. The fourth lens may have positive optical power, with its object-side surface being convex and its image-side surface being either concave or convex.

[0053] The rear lens group includes, in order from the object side to the image plane along the optical axis, the fifth lens, the sixth lens, the seventh lens, and the eighth lens. The fifth lens may have negative optical power, with its object-side surface being concave or convex, and its image-side surface being concave. The sixth lens may have positive optical power, with its object-side surface being convex, and its image-side surface being convex. The seventh lens may have negative optical power, with its object-side surface being concave, and its image-side surface being convex. The eighth lens may have negative optical power, with its object-side surface being convex near the optical axis, and its image-side surface being concave near the optical axis.

[0054] In some embodiments, the optical lens may further include an aperture, which may be located between the fourth lens and the fifth lens, that is, between the front lens group and the rear lens group. It can be understood that the aperture is used to limit the amount of incident light to change the brightness of the image. At the same time, an aperture for limiting the light beam is provided between the front lens group and the rear lens group, which can reduce the generation of ghost images in the optical lens, is beneficial to converge the light entering the optical system, reduce the aperture of the rear port of the optical lens, and the aperture arranged here also enables the optical lens to have a larger aperture, increasing the light input of the lens, so that the lens can also achieve high-definition imaging in a dim environment.

[0055] In some embodiments, the optical lens may further include a filter, which is disposed 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 imaging.

[0056] In some embodiments, the total optical length TTL of the optical lens and the effective focal length f of the optical lens satisfy: 2.4 < TTL / f < 3. Meeting the above conditions can effectively limit the length of the lens, which is beneficial to the miniaturization of the optical lens.

[0057] 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 the optical lens satisfy: 1.5 < TTL / IH < 1.7. Meeting the above conditions can better achieve the miniaturization of the lens. At the same time, when ensuring the same total length of the lens, it has a larger image plane, can match a larger-sized imaging chip to achieve high-definition imaging.

[0058] In some embodiments, the combined focal length fa of the front lens group and the combined focal length fb of the rear lens group satisfy: -0.8 < fa / fb < -0.5. Meeting the above conditions, by reasonably setting the ratio of the combined focal lengths of the front and rear lens groups, on the one hand, it is beneficial to the convergence of light, enabling the light entering the system from the front to smoothly enter the rear optical system, making the overall light path more gentle, and on the other hand, it is beneficial to optimizing aberrations and improving the overall resolution of the lens.

[0059] In some embodiments, the true image height IH corresponding to the maximum field angle of the optical lens and the aperture value Fno of the optical lens satisfy: 5.6 mm < IH / Fno < 6.1 mm. Meeting the above conditions can enable the lens to better achieve the balance of large target surface imaging and large aperture performance, make the pixel distribution sparser (i.e., the pixel point size is larger), can reduce noise in a darker environment, and the dynamic range will also be wider, and more details can be retained in the dark part, thereby improving the picture quality.

[0060] In some embodiments, the effective focal length f of the optical lens and the focal length f1 of the first lens satisfy: -25 < f1 / f < -2. Meeting the above conditions can make the first lens have an appropriate negative optical power, which is beneficial to receiving more light into the system and expanding the field angle of the optical lens.

[0061] In some embodiments, the curvature radius R1 of the object side of the first lens, the curvature radius R2 of the image side of the first lens, and the central thickness CT1 of the first lens on the optical axis satisfy: 0.85 < R1 / (R2 + CT1) < 1.3. Meeting the above conditions can make the first lens adopt a design similar to concentric circles, which is beneficial to making the light enter the rear lens gently, reducing the field curvature, correcting the off-axis aberration, and is beneficial to the correction of the aberration of the entire optical lens, improving the imaging quality of the optical lens.

[0062] In some embodiments, the effective focal length f of the optical lens and the focal length f2 of the second lens satisfy: -3.6 < f2 / f < -1.8. The curvature radius R4 of the image side of the second lens and the effective focal length f of the optical lens satisfy: -50 < R4 / f < -1.5. Meeting the above conditions can make the second lens have a large negative optical power, further diverge the incident light, avoid excessive light deflection caused by the overly concentrated optical power of the first lens, and reduce the difficulty of chromatic aberration correction of the optical lens.

[0063] In some embodiments, the effective focal length f of the optical lens and the focal length f3 of the third lens satisfy: 1.3 < f3 / f < 1.8; the effective focal length f of the optical lens and the focal length f4 of the fourth lens satisfy: 0.9 < f4 / f < 1.3. Meeting the above conditions, by setting the third and fourth lenses to have a large positive optical power, the incident light at the front end can be effectively converged, which is beneficial to correcting the aberration and distortion of the edge field caused by the front-end lens, making the lens have a small distortion and providing a high-definition imaging effect.

[0064] In some embodiments, the effective focal length f of the optical lens and the focal length f5 of the fifth lens satisfy: -1.85 < f5 / f < -1.4. Meeting the above conditions can make the fifth lens have an appropriate negative optical power, which is beneficial to increasing the imaging area of the optical lens and improving the imaging quality of the optical lens.

[0065] In some embodiments, the effective focal length f of the optical lens and the focal length f6 of the sixth lens satisfy: 1.2 < f6 / f < 1.7. Meeting the above conditions can make the sixth lens have an appropriate positive optical power, which is beneficial to the smooth transition of light, and at the same time balances the spherical aberration and field curvature of the fifth lens, improving the imaging quality of the optical lens.

[0066] In some embodiments, the effective focal length f of the optical lens and the focal length f7 of the seventh lens satisfy: -10 < f7 / f < -6; the focal length f7 of the seventh lens and the focal length f8 of the eighth lens satisfy: 4 < f7 / f8 < 7. Meeting the above conditions, by reasonably setting the refractive power relationship between the seventh and eighth lenses, the light rays in the marginal field of view can be effectively diverged. At the same time, combined with the curvature of the marginal area of the eighth lens, the exit angle of the light rays in the marginal field of view can be reduced, and the relative illumination of the marginal field of view can be improved.

[0067] In some embodiments, the effective focal length f of the optical lens and the focal length f8 of the eighth lens satisfy: -1.8 < f8 / f < -1.1. Meeting the above conditions, by setting the eighth lens to have a large negative refractive power, the incident light rays can be diverged to a large extent, causing the peripheral light rays and the central light rays to turn upwards and reach a higher imaging position, better realizing the large target surface imaging of the lens and improving the imaging quality.

[0068] [[ID=⑥]]In some embodiments, the central thickness CT1 of the first lens on the optical axis and the edge thickness ET1 of the first lens satisfy: 0.8 < CT1 / ET1 < 1. Meeting the above conditions, on the one hand, the first lens can have a relatively moderate thickness ratio, reducing the processing difficulty. On the other hand, the refractive degree of the light rays in the marginal field of view can be appropriately increased, facilitating more incident light rays to enter the system and realizing the wide viewing angle of the lens.

[0069] In some embodiments, the clear aperture DM11 of the object side of the first lens and the clear aperture DM82 of the image side of the eighth lens satisfy: 1.2 < DM11 / DM82 < 1.5. Meeting the above conditions, the lens can have a large incident aperture. While ensuring that as many light rays as possible enter the system, the area of the light rays entering the imaging surface is increased, which is beneficial to realizing the balance of the large image surface and the large aperture of the lens.

[0070] In some embodiments, the effective focal length f of the optical lens, the maximum field of view FOV of the optical lens, and the true image height IH corresponding to the maximum field of view of the optical lens satisfy: 65° < (f × FOV) / IH < 80°. Meeting the above range can balance the requirements of large-range detection and high-quality imaging and improve the adaptability of the optical lens.

[0071] In some embodiments, the effective focal length f of the optical lens and the true image height IH corresponding to the maximum field of view of the optical lens satisfy: 1.4 < IH / f < 1.85. Meeting the above conditions, the lens can have a large image surface and long focal length performance, and can match a large-size chip to achieve high-definition imaging.

[0072] It should be noted that in the translation of the content of item , the number "⑥" in the original text is likely an incorrect numbering and should be "" for correct processing. The above translation is adjusted accordingly.In some embodiments, the radius of curvature R3 of the object side surface of the second lens and the radius of curvature R4 of the image side surface of the second lens satisfy: 0.01 < R3 / R4 < 0.5. Meeting the above conditions, by reasonably setting the meniscus shape of the second lens, it is beneficial to receive large-angle incident light and control the incident light to enter the optical system more gently, thereby reducing the tolerance sensitivity of the optical system.

[0073] In some embodiments, the radius of curvature R11 of the object side surface of the sixth lens and the radius of curvature R12 of the image side surface of the sixth lens satisfy: -1.5 < R11 / R12 < -0.15. Meeting the above conditions, by reasonably setting the biconvex shape of the sixth lens, it is beneficial to better converge light, shorten the distance for light to reach the next lens, and is beneficial to reducing the total length of the optical lens.

[0074] In some embodiments, the spacing CT78 between the seventh lens and the eighth lens on the optical axis and the central thickness CT8 of the eighth lens on the optical axis satisfy: 1.2 < CT78 / CT8 < 2; the spacing CT78 between the seventh lens and the eighth lens on the optical axis and the central thickness CT7 of the seventh lens on the optical axis satisfy: 1.5 < CT78 / CT7 < 4. Meeting the above conditions is beneficial to the spatial arrangement of the seventh lens and the eighth lens, reduces the processing difficulty, and improves the production yield.

[0075] In some embodiments, the clear aperture DM1 of the first lens, the clear aperture DM2 of the second lens, the clear aperture DM3 of the third lens, and the clear aperture DM4 of the fourth lens satisfy: DM1 > DM2 > DM3 > DM4; the clear aperture DM5 of the fifth lens, the clear aperture DM6 of the sixth lens, the clear aperture DM7 of the seventh lens, and the clear aperture DM8 of the eighth lens satisfy: DM8 > DM7 > DM6 > DM5. Meeting the above conditions can, on the one hand, make the assembly of the lens more convenient, and on the other hand, while ensuring that the lens has a large light flux, it also has a small rear-end volume, better realizing the miniaturization of the lens volume.

[0076] In some embodiments, the combined focal length fa of the front lens group and the effective focal length f of the optical lens satisfy: 0.75 < fa / f < 1; meeting the above conditions, by reasonably distributing the combined focal length of the front-end lens group, it is beneficial to reduce the spherical aberration and field curvature generated by the front-end lens of the optical lens, and improve the imaging quality of the optical lens.

[0077] In some embodiments, the combined focal length fb of the rear lens group and the effective focal length f of the optical lens satisfy: -1.8 < fb / f < -1. Meeting the above conditions can diverge the light entering the system to a certain extent, which is beneficial to increasing the height of the light entering the image plane, and at the same time is beneficial to balancing the distortion and astigmatism generated by the front-end lens of the optical lens, and improving the imaging quality of the optical lens.

[0078] In some embodiments, the optical lens satisfies the conditional expressions: 6.5 mm < f < 8 mm, 18 mm < TTL < 20 mm, 1.9 < Fno < 2.1, 11 mm < IH < 12 mm, 110° < FOV < 120°, where f represents the effective focal length of the optical lens, TTL represents the overall optical length of the optical lens, Fno represents the aperture value of the optical lens, IH represents the true image height corresponding to the maximum field angle of the optical lens, and FOV represents the maximum field angle of the optical lens. Meeting the above conditions indicates that the optical lens provided by the embodiments of the present invention has at least the following advantages: a relatively large aperture value, enabling the lens to achieve high-definition imaging even in a relatively dark environment; a relatively large imaging surface, which can be matched with a relatively large-size chip to achieve high-definition imaging.

[0079] In some embodiments, all eight lenses in the optical lens may be made of plastic lenses or adopt a structure with a combination of glass and plastic materials. Preferably, the optical lens of the present invention adopts a lens structure with a combination of eight glass and plastic materials, which can improve the thermal stability performance. Specifically, the second lens and the third lens may be made of glass lenses, and the first lens, the fourth lens, the fifth lens, the sixth lens, the seventh lens, and the eighth lens are all plastic lenses; adopting a glass-plastic hybrid structure can effectively reduce costs, correct aberrations, reduce the volume, and provide an optical lens product with higher cost performance.

[0080] 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 may adopt spherical lenses or aspherical lenses. Compared with the spherical structure, the aspherical structure can effectively reduce the aberrations 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, in the optical lens provided by the present invention, the second lens and the third lens adopt spherical lenses, and the first lens, the fourth lens, the fifth lens, the sixth lens, the seventh lens, and the eighth lens may adopt aspherical lenses.

[0081] 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:

[0082] ;

[0083] 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 coefficients of the fourth-order, sixth-order, eighth-order, tenth-order, twelfth-order, fourteenth-order, and sixteenth-order surfaces respectively.

[0084] The present invention is further illustrated below with reference to several embodiments. In each embodiment, the thickness, radius of curvature, and material selection of each lens in the optical lens vary; for details, please refer to the parameter tables of each embodiment. The following embodiments are merely preferred embodiments of the present invention, but the present invention is not limited thereto. Any other changes, substitutions, combinations, or simplifications that do not deviate from the novelties of the present invention shall be considered equivalent replacements and are included within the scope of protection of the present invention.

[0085] Example 1

[0086] See also Figure 1 , which is a schematic structural diagram of an optical lens 100 provided in Example 1 of the present invention, wherein the optical lens 100 includes, along the optical axis from the object side to the imaging surface S19, a front optical group having positive optical power, an aperture ST, a rear optical group having negative optical power, and a filter G1;

[0087] The front lens group includes, in order from the object side to the imaging plane along the optical axis: a first lens L1, a second lens L2, a third lens L3, and a fourth lens L4.

[0088] The first lens L1 has negative refractive power, its object-side surface S1 is convex, and its image-side surface S2 is concave;

[0089] The second lens L2 has negative refractive power, its object-side surface S3 is concave, and its image-side surface S4 is convex;

[0090] The third lens L3 has positive refractive power, its object-side surface S5 is convex, and its image-side surface S6 is convex;

[0091] The fourth lens L4 has positive refractive power, its object-side surface S7 is convex, and its image-side surface S8 is concave near the optical axis;

[0092] The rear group includes, in order from the object side to the image plane along the optical axis: a fifth lens L5, a sixth lens L6, a seventh lens L7, and an eighth lens L8.

[0093] The fifth lens L5 has negative refractive power, its object-side surface S9 is convex, and its image-side surface S10 is concave.

[0094] The sixth lens L6 has positive refractive power, its object-side surface S11 is convex, and its image-side surface S12 is convex;

[0095] The seventh lens L7 has negative refractive power, its object-side surface S13 is concave, and its image-side surface S14 is convex;

[0096] The eighth lens L8 has negative refractive power, its object-side surface S15 is convex near the optical axis, and its image-side surface S16 is concave near the optical axis;

[0097] The object-side surface S17 and the image-side surface S18 of the filter G1 are both flat surfaces;

[0098] The imaging surface S19 is a plane.

[0099] The second lens L2 and the third lens L3 are glass spherical lenses; the first lens L1, the fourth lens L4, the fifth lens L5, the sixth lens L6, the seventh lens L7 and the eighth lens L8 are plastic aspherical lenses.

[0100] The relevant parameters of each lens in the optical lens 100 in Example 1 are shown in Table 1-1.

[0101] Table 1-1

[0102]

[0103] The surface parameters of the aspheric lens of the optical lens 100 in Example 1 are shown in Table 1-2.

[0104] Table 1-2

[0105]

[0106] In this embodiment, the astigmatism curve, the axial aberration curve, and the vertical chromatic aberration curve of the optical lens 100 are respectively as follows: Figure 2 、 Figure 3 、 Figure 4 shown.

[0107] Figure 2 The astigmatism curve of the optical lens 100 in this embodiment is shown, which shows the astigmatism of light in the meridional image plane and the sagittal image plane. 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 astigmatism of the meridional image plane and the sagittal image plane is controlled within ±0.1mm, indicating that the optical lens 100 can effectively correct astigmatism.

[0108] Figure 3 The following is a graph showing the axial aberration of the optical lens 100 in this embodiment, which shows the aberration of each wavelength on the optical axis at the imaging plane. The horizontal axis represents the axial aberration value (unit: mm), and the vertical axis represents the normalized pupil radius. As can be seen from the graph, the offset of the axial aberration is controlled within ±0.03mm, indicating that the optical lens 100 is able to effectively correct the axial aberration.

[0109] Figure 4A graph showing the vertical chromatic aberration of the optical lens 100 in this embodiment shows the chromatic aberration of each wavelength relative to the central wavelength (0.555 μm) at different image heights on the imaging plane. The horizontal axis represents the vertical chromatic aberration value of each wavelength relative to the central wavelength (unit: μm), and the vertical axis represents the normalized field of view angle. As can be seen from the graph, the vertical chromatic aberration for the longest and shortest wavelengths is controlled within ±1 μm, indicating that the optical lens 100 is capable of effectively correcting chromatic aberration.

[0110] Example 2

[0111] See also Figure 5 , shown is a schematic structural diagram of the optical lens 200 provided in Example 2 of the present invention. Compared with Example 1, this embodiment has the following main differences: the image-side surface S8 of the fourth lens L4 is convex; the object-side surface S9 of the fifth lens L5 is concave; and the optical parameters such as the curvature radius of each lens surface and the lens thickness are different.

[0112] The relevant parameters of each lens in the optical lens 200 in Example 2 are shown in Table 2-1.

[0113] Table 2-1

[0114]

[0115] The surface parameters of the aspheric lens of the optical lens 200 in Example 2 are shown in Table 2-2.

[0116] Table 2-2

[0117]

[0118] In this embodiment, the astigmatism curve, the axial aberration curve, and the vertical chromatic aberration curve of the optical lens 200 are respectively as follows: Figure 6 、 Figure 7 、 Figure 8 shown.

[0119] from Figure 6 It can be seen from the figure that the astigmatism of the meridional image plane and the sagittal image plane is controlled within ±0.1 mm, indicating that the optical lens 200 can correct the astigmatism well.

[0120] from Figure 7 It can be seen from the figure that the offset of the axial aberration is controlled within ±0.03 mm, indicating that the optical lens 200 can correct the axial aberration well.

[0121] from Figure 8 It can be seen from the figure that the vertical axis chromatic aberration of the longest wavelength and the shortest wavelength is controlled within ±1.5μm, indicating that the optical lens 200 can correct chromatic aberration well.

[0122] Example 3

[0123] See also Figure 9 , shown is a schematic structural diagram of the optical lens 300 provided in Example 3 of the present invention. Compared with Example 1, this embodiment has the following main differences: the image-side surface S8 of the fourth lens L4 is convex; and the optical parameters such as the curvature radius of each lens surface and the lens thickness are different.

[0124] The relevant parameters of each lens in the optical lens 300 in Example 3 are shown in Table 3-1.

[0125] Table 3-1

[0126]

[0127] The surface parameters of the aspheric lens of the optical lens 300 in Example 3 are shown in Table 3-2.

[0128] Table 3-2

[0129]

[0130] In this embodiment, the astigmatism curve, the axial aberration curve, and the vertical chromatic aberration curve of the optical lens 300 are respectively as follows: Figure 10 、 Figure 11 、 Figure 12 shown.

[0131] from Figure 10 It can be seen from the figure that the astigmatism of the meridional image plane and the sagittal image plane is controlled within ±0.1 mm, indicating that the optical lens 300 can correct the astigmatism well.

[0132] from Figure 11 It can be seen from the figure that the offset of the axial aberration is controlled within ±0.02 mm, indicating that the optical lens 300 can correct the axial aberration well.

[0133] from Figure 12 It can be seen from the figure that the vertical axis chromatic aberration of the longest wavelength and the shortest wavelength is controlled within ±2μm, indicating that the optical lens 300 can correct chromatic aberration well.

[0134] Example 4

[0135] See also Figure 13 , shown is a schematic structural diagram of an optical lens 400 provided in Example 4 of the present invention. Compared with Example 1, this embodiment has the following main differences: the image-side surface S8 of the fourth lens L4 is convex; the object-side surface S9 of the fifth lens L5 is concave; and the optical parameters such as the curvature radius of each lens surface and the lens thickness are different.

[0136] The relevant parameters of each lens in the optical lens 400 in Example 4 are shown in Table 4-1.

[0137] Table 4-1

[0138]

[0139] The surface parameters of the aspheric lens of the optical lens 400 in Example 4 are shown in Table 4-2.

[0140] Table 4-2

[0141]

[0142] In this embodiment, the astigmatism curve, the axial aberration curve, and the vertical chromatic aberration curve of the optical lens 400 are respectively as follows: Figure 14 、 Figure 15 、 Figure 16 shown.

[0143] from Figure 14 It can be seen from the figure that the astigmatism of the meridional image plane and the sagittal image plane is controlled within ±0.1 mm, indicating that the optical lens 400 can correct the astigmatism well.

[0144] from Figure 15 It can be seen that the offset of the axial aberration is controlled within ±0.03 mm, indicating that the optical lens 400 can correct the axial aberration well.

[0145] from Figure 16 It can be seen from the figure that the vertical axis chromatic aberration of the longest wavelength and the shortest wavelength is controlled within ±1.5μm, indicating that the optical lens 400 can correct chromatic aberration well.

[0146] Please refer to Table 5, which shows the optical characteristics corresponding to the above embodiments, including the effective focal length f, total optical length TTL, aperture value Fno, real image height IH corresponding to the maximum field of view angle, chief ray incidence angle CRA at the maximum image height, maximum field of view angle FOV, and the numerical value corresponding to each conditional expression in each embodiment.

[0147] Table 5

[0148]

[0149] In summary of the above embodiments, the optical lens provided by the present invention utilizes an eight-piece glass-plastic hybrid structure. Through specific surface configurations and rational optical power distribution, the optical lens is compact, effectively shortening its overall length and facilitating miniaturization. Its large aperture enables high-definition imaging even in dark environments. Furthermore, its large imaging surface allows it to be compatible with larger chips for high-definition imaging. Furthermore, it can rationally correct the overall aberrations of the optical lens, achieving high pixel count and enhancing the imaging quality of the optical lens.

[0150] Throughout this specification, reference to terms such as "one embodiment," "some embodiments," "examples," "specific examples," and "some examples" means that the specific features, structures, materials, or characteristics described in conjunction with that embodiment or example are included in at least one embodiment or example of the present invention. In this specification, schematic representations 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 any one or more embodiments or examples.

[0151] The above-described embodiments merely illustrate several implementations of the present invention, and while their descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the present invention. It should be noted that a person skilled in the art would be able to make numerous variations and improvements without departing from the spirit of the present invention, all of which fall within the scope of protection of the present invention. Therefore, the scope of protection of the present invention shall be determined by the appended claims.

Claims

1. An optical lens, comprising eight lenses, characterized in that: It successively includes from the object side to the imaging surface along the optical axis: a front group with positive optical power and a rear group with negative optical power; The front group successively includes from the object side to the imaging surface along the optical axis: A first lens with negative optical power, whose object side is convex and whose image side is concave; A second lens with negative optical power, whose object side is concave and whose image side is convex; A third lens with positive optical power, whose object side is convex and whose image side is convex; A fourth lens with positive optical power, whose object side is convex; The rear group successively includes from the object side to the imaging surface along the optical axis: A fifth lens with negative optical power, whose image side is concave; A sixth lens with positive optical power, whose object side is convex and whose image side is convex; A seventh lens with negative optical power, whose object side is concave and whose image side is convex; An eighth lens with negative optical power, whose object side is convex near the optical axis and whose image side is concave near the optical axis; Wherein, the total optical length TTL of the optical lens and the effective focal length f of the optical lens satisfy: 2.4 < TTL / f < 3; the total optical length TTL of the optical lens and the true image height IH corresponding to the maximum field angle of the optical lens satisfy: 1.5 < TTL / IH < 1.

7.

2. The optical lens according to claim 1, wherein: The combined focal length fa of the front group and the combined focal length fb of the rear group satisfy: -0.8 < fa / fb < -0.

5.

3. The optical lens according to claim 1, wherein: The true image height IH corresponding to the maximum field angle of the optical lens and the f-number Fno of the optical lens satisfy: 5.6 mm < IH / Fno < 6.1 mm.

4. The optical lens according to claim 1, wherein: The effective focal length f of the optical lens and the focal length f1 of the first lens satisfy: -25 < f1 / f < -2; the object side curvature radius R1 of the first lens, the image side curvature radius R2 of the first lens and the central thickness CT1 of the first lens on the optical axis satisfy: 0.85 < R1 / (R2 + CT1) < 1.

3.

5. The optical lens according to claim 1, wherein: The effective focal length f of the optical lens and the focal length f2 of the second lens satisfy: -3.6 < f2 / f < -1.8; the image side curvature radius R4 of the second lens and the effective focal length f of the optical lens satisfy: -50 < R4 / f < -1.

5.

6. The optical lens according to claim 1, wherein: The effective focal length f of the optical lens and the focal length f3 of the third lens satisfy: 1.3 < f3 / f < 1.8; the effective focal length f of the optical lens and the focal length f4 of the fourth lens satisfy: 0.9 < f4 / f < 1.

3.

7. The optical lens according to claim 1, wherein: The effective focal length f of the optical lens and the focal length f5 of the fifth lens satisfy: -l.85 < f5 / f < -1.4; the effective focal length f of the optical lens and the focal length f6 of the sixth lens satisfy: 1.2 < f6 / f < 1.

7.

8. The optical lens according to claim 1, wherein: The effective focal length f of the optical lens and the focal length f7 of the seventh lens satisfy: -10 < f7 / f < -6; the focal length f7 of the seventh lens and the focal length f8 of the eighth lens satisfy: 4 < f7 / f8 < 7.

9. The optical lens according to claim 1, wherein: The effective focal length f of the optical lens and the focal length f8 of the eighth lens satisfy: -1.8 < f8 / f < -1.1; the central thickness CT1 of the first lens on the optical axis and the edge thickness ET1 of the first lens satisfy: 0.8 < CT1 / ET1 < 1.

10. The optical lens according to claim 1, wherein: The clear aperture DM11 of the object side of the first lens and the clear aperture DM82 of the image side of the eighth lens satisfy: 1.2 < DM11 / DM82 < 1.5.

Images