Optical lens

Abstract

The application provides an optical lens, which has 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, whose object side surface is a convex surface and whose image side surface is a concave surface; a second lens with negative optical power, whose object side surface is a concave surface and whose image side surface is a convex surface; a third lens with positive optical power, whose object side surface is a convex surface and whose image side surface is a plane; a fourth lens with positive optical power, whose object side surface is a convex surface and whose image side surface is a convex surface; a fifth lens with negative optical power, whose object side surface is a convex surface near the optical axis and whose image side surface is a concave surface; a sixth lens with positive optical power, whose object side surface is a concave surface and whose image side surface is a convex surface; a seventh lens with negative optical power, whose object side surface is a convex surface and whose image side surface is a concave surface near the optical axis; and an eighth lens with positive optical power. The optical lens provided by the application 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 particularly to an optical lens. Background Art

[0002] A video lens is an optical lens designed specifically for video communication and is widely used in scenarios such as remote conferencing, online education, live streaming, etc. As an important part of video conferencing equipment, the video lens performs image acquisition and imaging to meet the virtual reality communication during the conference, and its performance directly affects the clarity, smoothness, and stability of video conferencing. With the continuous improvement of the technical index requirements of video conferencing systems, the imaging range of the lens, that is, the size of the chip, is getting larger and the heat generated by the chip is also increasing. The operating temperature of the lens will increase with the operating time of the device. However, for most existing lenses, the imaging quality will significantly decline as the temperature rises. Therefore, how to enable the lens to achieve high-quality imaging at different temperatures is an urgent problem to be solved at present. Summary of the Invention

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

[0004] The present invention provides an optical lens, and the number of lenses with optical power is eight. Along the optical axis from the object side to the imaging surface, it successively includes: 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 flat; A fourth lens with positive optical power, whose object side is convex and whose image side is convex; A fifth lens with negative optical power, whose object side is convex near the optical axis and whose image side is concave; A sixth lens with positive optical power, whose object side is concave and whose image side is convex; A seventh lens with negative optical power, whose object side is convex and whose image side is concave near the optical axis; An eighth lens with positive 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: 3.8 < TTL / f < 4.2; 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: 1.38 < TTL / IH < 1.43.

[0005] Further preferably, the focal length f1 of the first lens and the effective focal length f of the optical lens satisfy: -2.6 < f1 / f < -1.5; the focal length f2 of the second lens and the effective focal length f of the optical lens satisfy: -5.5 < f2 / f < -4.

[0006] Further preferably, the focal length f3 of the third lens and the effective focal length f of the optical lens satisfy: 1.4 < f3 / f < 2.

[0007] Further preferably, the focal length f4 of the fourth lens and the effective focal length f of the optical lens satisfy: 1.1 < f4 / f < 1.5.

[0008] Further preferably, the focal length f5 of the fifth lens and the effective focal length f of the optical lens satisfy: -1.8 < f5 / f < -1.4; the object-side curvature radius R9 of the fifth lens and the effective focal length f of the optical lens satisfy: 1.6 < R9 / f < 1.8.

[0009] Further preferably, the focal length f6 of the sixth lens and the effective focal length f of the optical lens satisfy: 1.3 < f6 / f < 1.7; the object-side curvature radius R11 of the sixth lens and the effective focal length f of the optical lens satisfy: -1.65 < R11 / f < -1.45.

[0010] Further preferably, the focal length f7 of the seventh lens and the effective focal length f of the optical lens satisfy: -2.8 < f7 / f < -2.2.

[0011] Further preferably, the focal length f8 of the eighth lens and the effective focal length f of the optical lens satisfy: 10 < f8 / f < 28; the image-side curvature radius R16 of the sixth lens and the effective focal length f of the optical lens satisfy: 0.8 < R16 / f < 1.2.

[0012] Further preferably, the object-side clear aperture radius DM11 of the first lens and the image-side clear aperture radius DM82 of the eighth lens satisfy: 0.82 < DM11 / DM82 < 0.92.

[0013] Further preferably, the combined focal length f12 of the first lens and the second lens and the effective focal length f of the optical lens satisfy: -1.6 < f12 / f < -1; the combined focal length f67 of the sixth lens and the seventh lens and the effective focal length f of the optical lens satisfy: 2.2 < f67 / f < 3.3.

[0014] Compared with existing technologies, 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, giving the lens one or more advantages such as miniaturization, large target surface, large field of view, small distortion, and high imaging quality. Attached Figure Description

[0015] 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: Figure 1 This is a schematic diagram of the optical lens in Embodiment 1 of the present invention.

[0016] Figure 2 This is a field curvature curve diagram of the optical lens in Embodiment 1 of the present invention.

[0017] Figure 3 This is the F-Tan(θ) distortion curve of the optical lens in Embodiment 1 of the present invention.

[0018] Figure 4 This is a chromatic aberration curve of the optical lens in Embodiment 1 of the present invention.

[0019] Figure 5 This is a relative illumination curve of the optical lens in Embodiment 1 of the present invention.

[0020] Figure 6 This is the MTF curve of the optical lens in Embodiment 1 of the present invention at an operating temperature of 20°C.

[0021] Figure 7 This is a schematic diagram of the optical lens structure in Embodiment 2 of the present invention.

[0022] Figure 8 This is a field curvature curve diagram of the optical lens in Embodiment 2 of the present invention.

[0023] Figure 9 This is the F-Tan(θ) distortion curve of the optical lens in Embodiment 2 of the present invention.

[0024] Figure 10 This is a chromatic aberration curve of the optical lens in Embodiment 2 of the present invention.

[0025] Figure 11 This is a relative illumination curve of the optical lens in Embodiment 2 of the present invention.

[0026] Figure 12 This is the MTF curve of the optical lens in Embodiment 2 of the present invention at an operating temperature of 20°C.

[0027] Figure 13This is a schematic diagram of the optical lens in Embodiment 3 of the present invention.

[0028] Figure 14 This is a field curvature curve diagram of the optical lens in Embodiment 3 of the present invention.

[0029] Figure 15 This is the F-Tan(θ) distortion curve of the optical lens in Embodiment 3 of the present invention.

[0030] Figure 16 This is a chromatic aberration curve of the optical lens in Embodiment 3 of the present invention.

[0031] Figure 17 This is a relative illumination curve of the optical lens in Embodiment 3 of the present invention.

[0032] Figure 18 This is the MTF curve of the optical lens in Embodiment 3 of the present invention at an operating temperature of 20°C.

[0033] The following detailed description, in conjunction with the accompanying drawings, will further illustrate the present invention. Detailed Implementation

[0034] 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.

[0035] 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.

[0036] 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.

[0037] 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.

[0038] 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.

[0039] 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.

[0040] 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.

[0041] The optical lens provided in this embodiment of the invention has eight lenses with optical power, which are arranged sequentially along the optical axis from the object side to the imaging plane as follows: 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.

[0042] In some embodiments, the first lens may have negative optical power, with a convex object-side surface and a concave image-side surface. The second lens may have negative optical power, with a concave object-side surface and a convex image-side surface. The third lens may have positive optical power, with a convex object-side surface and a flat image-side surface. The fourth lens may have positive optical power, with both its object-side and image-side surfaces being convex. The fifth lens may have negative optical power, with a convex object-side surface near the optical axis and a concave image-side surface. The sixth lens may have positive optical power, with a concave object-side surface and a convex image-side surface. The seventh lens may have negative optical power, with a convex object-side surface and a concave image-side surface near the optical axis. The eighth lens may have positive optical power, with a convex object-side surface near the optical axis and a concave image-side surface near the optical axis.

[0043] In some embodiments, the optical lens may also include an aperture stop, which may be located between the third and fourth lenses. 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.

[0044] In some embodiments, the optical lens may further include a filter disposed between the eighth lens and the imaging surface. 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.

[0045] In some embodiments, the total optical length TTL of the optical lens and the effective focal length f of the optical lens satisfy: 3.8 < TTL / f < 4.2. Meeting the above range can effectively limit the length of the lens and better achieve the miniaturization of the optical lens.

[0046] 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: 1.38 < TTL / IH < 1.43. Meeting the above range 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 and can match a larger-sized imaging chip to achieve high-definition imaging.

[0047] In some embodiments, the focal length f1 of the first lens and the effective focal length f of the optical lens satisfy: -2.6 < f1 / f < -1.5; the focal length f2 of the second lens and the effective focal length f of the optical lens satisfy: -5.5 < f2 / f < -4. Meeting the above range, by reasonably setting the negative refractive power combination of the first and second lenses, a large amount of light can be received into the system to a large extent, which is beneficial to increasing the field angle of the optical lens.

[0048] In some embodiments, the focal length f3 of the third lens and the effective focal length f of the optical lens satisfy: 1.4 < f3 / f < 2. Meeting the above range, by setting the third lens to have a large positive refractive power, the light entering the system can be effectively converged, improving the light collection ability of the marginal field and improving the overall imaging quality.

[0049] In some embodiments, the focal length f4 of the fourth lens and the effective focal length f of the optical lens satisfy: 1.1 < f4 / f < 1.5. Meeting the above range, by reasonably setting the refractive power of the fourth lens, it is beneficial to further converge the light, reduce the difficulty of correcting the marginal field distortion, ensure that the lens has a small distortion while achieving a large field angle, and improve the overall imaging quality.

[0050] In some embodiments, the focal length f5 of the fifth lens and the effective focal length f of the optical lens satisfy: -1.8 < f5 / f < -1.4; the curvature radius R9 of the object side surface of the fifth lens and the effective focal length f of the optical lens satisfy: 1.6 < R9 / f < 1.8. Meeting the above range, by reasonably setting the negative refractive power and surface shape of the fifth lens, the light can be appropriately diverged, which is beneficial to increasing the imaging area of the optical lens and improving the imaging quality of the optical lens.

[0051] In some embodiments, the focal length f6 of the sixth lens and the effective focal length f of the optical lens satisfy: 1.3 < f6 / f < 1.7; the object-side curvature radius R11 of the sixth lens and the effective focal length f of the optical lens satisfy: -1.65 < R11 / f < -1.45. Meeting the above ranges, by reasonably setting the positive refractive power and surface shape of the sixth lens, it is beneficial to the smooth transition of light, while balancing the spherical aberration and field curvature of the fifth lens, and improving the imaging quality of the optical lens.

[0052] In some embodiments, the focal length f7 of the seventh lens and the effective focal length f of the optical lens satisfy: -2.8 < f7 / f < -2.2. Meeting the above range, by reasonably setting the negative refractive power of the seventh lens, the light in the marginal field of view can be effectively diverged, increasing the height of the light entering the imaging surface, which is beneficial to achieving large target surface imaging of the lens.

[0053] In some embodiments, the focal length f8 of the eighth lens and the effective focal length f of the optical lens satisfy: 10 < f8 / f < 28; the image-side curvature radius R16 of the sixth lens and the effective focal length f of the optical lens satisfy: 0.8 < R16 / f < 1.2. Meeting the above ranges, by reasonably setting the positive refractive power and surface shape of the eighth lens, the light in the marginal field of view can be effectively converged, reducing the correction difficulty of the marginal field of view, and ensuring that the lens has high imaging quality throughout the imaging range.

[0054] In some embodiments, the clear aperture radius DM11 of the object side of the first lens and the clear aperture radius DM82 of the image side of the eighth lens satisfy: 0.82 < DM11 / DM82 < 0.92. Meeting the above range, by reasonably setting the aperture relationship of the first and last lenses in the lens, both the light incident surface is increased and the light exit height is ensured, which can better achieve the balance of wide-angle imaging and large image surface of the lens.

[0055] In some embodiments, the combined focal length f12 of the first lens and the second lens and the effective focal length f of the optical lens satisfy: -1.6 < f12 / f < -1. Meeting the above range, by reasonably setting the combined focal length of the first and second lenses, the object surface light in the wide field of view can be converged into the lens, which is beneficial to achieving large wide-angle imaging of the lens.

[0056] In some embodiments, the combined focal length f67 of the sixth lens and the seventh lens and the effective focal length f of the optical lens satisfy: 2.2 < f67 / f < 3.3. Meeting the above range, by reasonably setting the combined focal length of the sixth and seventh lenses, it is beneficial to the smooth transition of light and improves the imaging quality of the lens.

[0057] In some embodiments, the effective focal length f of the optical lens, the maximum field angle FOV of the optical lens, and the true image height IH corresponding to the maximum field angle of the optical lens satisfy: 39° < (f × FOV) / IH < 41.5°. Meeting the above range and reasonably setting the relationship between the focal length, field angle, and image height of the optical lens is conducive to achieving the balance between the large field angle and large image plane imaging of the optical lens.

[0058] 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: 2.8 < IH / f < 2.9. Meeting the above range can achieve a larger field angle and imaging range, and can achieve the large image plane characteristic while ensuring the depth of field of the optical lens, thereby improving the imaging quality of the optical system.

[0059] In some embodiments, the focal length f3 of the third lens and the focal length f4 of the fourth lens satisfy: 1.22 < f3 / f4 < 1.32. Meeting the above range can effectively converge the incident light, which is beneficial to correcting the field curvature and distortion of the optical lens and improving the imaging quality of the optical lens.

[0060] In some embodiments, the focal length f5 of the fifth lens and the focal length f6 of the sixth lens satisfy: -1.25 < f5 / f6 < -0.95. Meeting the above range is beneficial to balancing the astigmatism and field curvature of the optical lens and improving the imaging quality of the optical lens.

[0061] In some embodiments, the focal length f7 of the seventh lens and the focal length f8 of the eighth lens satisfy: -0.25 < f7 / f8 < -0.08. Meeting the above range, by reasonably setting the focal length relationship between the seventh and eighth lenses, the light rays in the marginal field can be effectively diverged. At the same time, combined with the bending of the marginal area of the eighth lens, the exit angle of the light rays in the marginal field can be reduced, and the relative illumination of the marginal field can be improved.

[0062] In some embodiments, the object side curvature radius R3 of the second lens and the effective focal length f of the optical lens satisfy: -1.55 < R3 / f < -1.4; the image side curvature radius R4 of the second lens and the effective focal length f of the optical lens satisfy: -3.5 < R4 / f < -3. Meeting the above range and reasonably setting the meniscus shape of the second lens is beneficial to receiving large-angle incident light and controlling the incident light to enter the optical system more gently, thereby reducing the tolerance sensitivity of the optical system.

[0063] In some embodiments, the refractive index Nd3 of the third lens satisfies: 1.75 < Nd3 < 1.95. Meeting the above range, the third lens uses a glass lens with a high refractive index, which is beneficial to the back focal compensation of the system at high and low temperatures, improves the imaging quality of the system at high and low temperatures, and can better achieve the thermal stability of the lens when paired with other plastic lenses.

[0064] In some embodiments, the optical lens satisfies the conditional formula: 4.1 mm < f < 4.2 mm, 16.2 mm < TTL < 17 mm, 2 < Fno < 2.1, 11.5 mm < IH < 12 mm, 112° < FOV < 118°, 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 viewing angle of the optical lens, and FOV represents the maximum viewing angle of the optical lens. Meeting the above conditions indicates that the optical lens provided by the embodiments of the present invention has a relatively large viewing angle, a relatively small overall optical length, and a relatively large imaging surface, and can be matched with a chip of a relatively large size to achieve high-definition imaging.

[0065] 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.

[0066] 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 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, in the optical lens provided by the present invention, the second lens and the third lens may 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.

[0067] In each embodiment of the present invention, when the lens adopts an aspherical lens, the shapes of the aspherical surfaces of the optical lens satisfy the following equation: ; where z is the distance between the curved surface and the vertex of the curved surface in the optical axis direction, h is the distance from the optical axis to the curved surface, c is the curvature of the vertex of the curved surface, K is the 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.

[0068] 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. Example 1

[0069] 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 S19, the following components in sequence: a first lens L1, a second lens L2, a third lens L3, an aperture ST, a fourth lens L4, a fifth lens L5, a sixth lens L6, a seventh lens L7, an eighth lens L8, and a filter G1. Among them, the first lens L1 has negative optical power, its object side S1 is convex, and its image side S2 is concave. The second lens L2 has negative optical power, its object side S3 is concave, and its image side S4 is convex. The third lens L3 has positive optical power, its object side S5 is convex, and its image side S6 is flat. The fourth lens L4 has positive optical power, its object side S7 is convex, and its image side S8 is convex. 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. The sixth lens L6 has positive optical power, its object side S11 is concave, and its image side S12 is convex. The seventh lens L7 has negative optical power, its object side S13 is convex, and its image side S14 is concave near the optical axis. The eighth lens L8 has positive optical power, its object side S15 is convex near the optical axis, and its image side S16 is concave near the optical axis. The object-side surface S17 and the image-side surface S18 of filter G1 are both planar. The imaging plane S19 is a plane.

[0070] 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 all plastic aspherical lenses.

[0071] The relevant parameters of each lens in the optical lens 100 in Example 1 are shown in Table 1-1.

[0072] Table 1-1 The surface profile parameters of the aspherical lens of the optical lens 100 in Example 1 are shown in Table 1-2.

[0073] Table 1-2 In this embodiment, the field curvature curve, F-Tan(θ) distortion curve, transverse chromatic aberration curve, relative illuminance curve, and MTF curve of the optical lens 100 at an operating temperature of 20°C are respectively as follows: Figure 2 , Figure 3 , Figure 4 , Figure 5 , Figure 6 As shown.

[0074] Figure 2 The field curvature curve of Embodiment 1 is shown, which represents the field curvature of light rays in the meridional and sagittal image planes. The horizontal axis represents the offset (unit: mm), and the vertical axis represents the field of view (unit: °). As can be seen from the figure, the field curvature of the meridional and sagittal image planes is controlled within ±0.2 mm, indicating that the optical lens 100 can effectively correct the field curvature.

[0075] Figure 3 The F-Tan(θ) distortion curve of Example 1 is shown, which represents the F-Tan(θ) distortion of light at different image heights on the imaging plane. The horizontal axis represents the distortion value (unit: %), and the vertical axis represents the field of view (unit: °). As can be seen from the figure, the F-Tan(θ) distortion of the optical lens is controlled within -10% to 1%, indicating that the optical lens 100 can correct distortion well.

[0076] 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 field of view (unit: °). As can be seen from the diagram, the transverse chromatic aberration of the longest and shortest wavelengths is controlled within -2 μm to 4 μm, indicating that the optical lens 100 can effectively correct chromatic aberration.

[0077] Figure 5 The relative illumination curves for Example 1 are shown, representing the relative illumination values ​​at different field-of-view angles on the imaging plane. The horizontal axis represents the field-of-view angle (unit: °), and the vertical axis represents the relative illumination (unit: %). As can be seen from the figure, the relative illumination value of the optical lens is still greater than 28% at the maximum half-field-of-view angle, indicating that the optical lens 100 has good relative illumination.

[0078] Figure 6The MTF curve of Example 1 at an operating temperature of 20°C is shown, representing the lens imaging modulation at different spatial frequencies in various fields of view. The horizontal axis represents spatial frequency (unit: lp / mm), and the vertical axis represents MTF value. As can be seen from the figure, the MTF value of this example is above 50% across the entire field of view. Within the range of 0–100 lp / mm, the MTF curve decreases smoothly and uniformly from the center to the edge of the field of view, exhibiting good imaging quality and detail resolution at both low and high frequencies. Example 2

[0079] Please see Figure 7 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 optical parameters such as the radius of curvature and lens thickness of each lens surface are different.

[0080] The relevant parameters of each lens in the optical lens 200 in Example 2 are shown in Table 2-1.

[0081] Table 2-1 The surface profile parameters of the aspherical lens of the optical lens 200 in Example 2 are shown in Table 2-2.

[0082] Table 2-2 In this embodiment, the field curvature curve, F-Tan(θ) distortion curve, transverse chromatic aberration curve, relative illuminance curve, and MTF curve of the optical lens 200 at an operating temperature of 20°C are respectively as follows: Figure 8 , Figure 9 , Figure 10 , Figure 11 , Figure 12 As shown.

[0083] from Figure 8 As can be seen, the field curvature of the meridional and sagittal image planes is controlled within ±0.2mm, indicating that the optical lens 200 can effectively correct the field curvature.

[0084] from Figure 9 As can be seen, the F-Tan(θ) distortion of the optical lens is controlled within -8% to 1%, indicating that the optical lens 200 can correct distortion well.

[0085] from Figure 10 As can be seen, the chromatic aberration of the longest and shortest wavelengths is controlled within -1μm to 3μm, indicating that the optical lens 200 can correct chromatic aberration well.

[0086] from Figure 11As can be seen, the relative illumination value of the optical lens is still greater than 25% at the maximum half field of view, indicating that the optical lens 200 has good relative illumination.

[0087] from Figure 12 As can be seen, the MTF value of this embodiment is above 50% throughout the entire field of view. In the range of 0 to 100 lp / mm, the MTF curve decreases smoothly and evenly from the center to the edge of the field of view. It has good imaging quality and good detail resolution in both low and high frequency conditions. Example 3

[0088] Please see Figure 13 The figure shown is 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 optical parameters such as the radius of curvature and lens thickness of each lens surface are different.

[0089] The relevant parameters of each lens in the optical lens 300 in Example 3 are shown in Table 3-1.

[0090] Table 3-1 The surface profile parameters of the aspherical lens of the optical lens 300 in Example 3 are shown in Table 3-2.

[0091] Table 3-2 In this embodiment, the field curvature curve, F-Tan(θ) distortion curve, transverse chromatic aberration curve, relative illuminance curve, and MTF curve of the optical lens 300 at an operating temperature of 20°C are respectively as follows: Figure 14 , Figure 15 , Figure 16 , Figure 17 , Figure 18 As shown.

[0092] from Figure 14 As can be seen, the field curvature of the meridional and sagittal image planes is controlled within ±0.2mm, indicating that the optical lens 300 can effectively correct the field curvature.

[0093] from Figure 15 As can be seen, the F-Tan(θ) distortion of the optical lens is controlled within -8% to 1%, indicating that the optical lens 300 can correct distortion well.

[0094] from Figure 16 As can be seen, the chromatic aberration of the longest and shortest wavelengths is controlled within -1μm to 3μm, indicating that the optical lens 300 can correct chromatic aberration well.

[0095] from Figure 17As can be seen, the relative illumination value of the optical lens is still greater than 25% at the maximum half field of view, indicating that the optical lens 300 has good relative illumination.

[0096] from Figure 18 As can be seen, the MTF value of this embodiment is above 50% throughout the entire field of view. In the range of 0 to 100 lp / mm, the MTF curve decreases smoothly and evenly from the center to the edge of the field of view. It has good imaging quality and good detail resolution in both low and high frequency conditions.

[0097] 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, true image height IH corresponding to the maximum field of view, maximum field of view FOV, and the numerical values ​​corresponding to each conditional expression in each embodiment.

[0098] Table 4 In summary, the optical lens provided by this invention employs eight lenses with specific optical powers. Through specific surface shape combinations and reasonable optical power allocation, it can improve the imaging quality of the optical lens, reduce aberrations, exhibit low distortion, and enhance the overall image quality. It also features a short overall length, facilitating device miniaturization; a large imaging surface, allowing for matching with larger chips to achieve high-definition imaging; a wide field of view, providing a broader shooting perspective for scenarios such as video conferencing, capturing more image information; and the use of a glass-plastic hybrid design helps reduce weight and cost, improves thermal stability, and minimizes temperature drift.

[0099] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "example," "specific example," and "some examples" 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.

[0100] 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 comprising eight lenses having optical power, characterized in that, It successively includes from the object side to the imaging surface along the optical axis: A first lens with a negative optical power, whose object side is convex and whose image side is concave; A second lens with a negative optical power, whose object side is concave and whose image side is convex; A third lens with a positive optical power, whose object side is convex and whose image side is flat; A fourth lens with a positive optical power, whose object side is convex and whose image side is convex; A fifth lens with a negative optical power, whose object side is convex near the optical axis and whose image side is concave; A sixth lens with a positive optical power, whose object side is concave and whose image side is convex; A seventh lens with a negative optical power, whose object side is convex and whose image side is concave near the optical axis; An eighth lens with a positive 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: 3.8 < TTL / f < 4.2; 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: 1.38 < TTL / IH < 1.

43.

2. The optical lens according to claim 1, characterized in that, The focal length f1 of the first lens and the effective focal length f of the optical lens satisfy: -2.6 < f1 / f < -1.5; the focal length f2 of the second lens and the effective focal length f of the optical lens satisfy: -5.5 < f2 / f < -4.

3. The optical lens according to claim 1, characterized in that, The focal length f3 of the third lens and the effective focal length f of the optical lens satisfy: 1.4 < f3 / f < 2.

4. The optical lens according to claim 1, characterized in that, The focal length f4 of the fourth lens and the effective focal length f of the optical lens satisfy: 1.1 < f4 / f < 1.

5.

5. The optical lens according to claim 1, characterized in that, The focal length f5 of the fifth lens and the effective focal length f of the optical lens satisfy: -1.8 < f5 / f < -1.4; the curvature radius R9 of the object side of the fifth lens and the effective focal length f of the optical lens satisfy: 1.6 < R9 / f < 1.

8.

6. The optical lens according to claim 1, characterized in that, The focal length f6 of the sixth lens and the effective focal length f of the optical lens satisfy: 1.3 < f6 / f < 1.7; the curvature radius R11 of the object side of the sixth lens and the effective focal length f of the optical lens satisfy: -1.65 < R11 / f < -1.

45.

7. The optical lens according to claim 1, characterized in that, The focal length f7 of the seventh lens and the effective focal length f of the optical lens satisfy: -2.8 < f7 / f < -2.

2.

8. The optical lens according to claim 1, characterized in that, The focal length f8 of the eighth lens and the effective focal length f of the optical lens satisfy: 10 < f8 / f < 28; the curvature radius R16 of the image side of the sixth lens and the effective focal length f of the optical lens satisfy: 0.8 < R16 / f < 1.

2.

9. The optical lens according to claim 1, characterized in that, The clear aperture radius DM11 of the object side of the first lens and the clear aperture radius DM82 of the image side of the eighth lens satisfy: 0.82 < DM11 / DM82 < 0.

92.

10. The optical lens according to claim 1, characterized in that, The combined focal length f12 of the first lens and the second lens and the effective focal length f of the optical lens satisfy: -1.6 < f12 / f < -1; the combined focal length f67 of the sixth lens and the seventh lens and the effective focal length f of the optical lens satisfy: 2.2 < f67 / f < 3.3.

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