Optical lens

Abstract

The invention provides an optical lens, which sequentially comprises a first lens with negative focal power from an object side to an imaging surface along an optical axis, a second lens with negative focal power, a third lens with negative focal power and a fourth lens with negative focal power from the object side to the imaging surface, the second lens has negative focal power, the object side surface of the second lens is a concave surface near the optical axis, and the image side surface of the second lens is a concave surface; the third lens has positive focal power, and the object side surface of the third lens is a convex surface near the optical axis; the object side surface of the fourth lens is a concave surface, and the image side surface of the fourth lens is a convex surface; the object side surface of the fifth lens is a convex surface, and the image side surface of the fifth lens is a convex surface; the sixth lens has negative focal power, and the image side surface of the sixth lens is a concave surface; the object side surface of the seventh lens is a convex surface, and the image side surface of the seventh lens is a convex surface; and the object side surface of the eighth lens is a convex surface near the optical axis, and the image side surface of the eighth lens is a concave surface. The imaging quality of the optical lens can be improved, and the optical lens has the advantage of being excellent in 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] With the rapid development of drones, security, automobiles, meteorology, medical treatment, VR, AR and other fields, higher and higher requirements are placed on the field of view of the lenses they carry. Wide-angle lenses introduce barrel distortion to compress the light at the edge of the field of view as much as possible, thereby achieving an ultra-wide-angle lens with a field of view of more than 200°. At present, there are still many problems with ultra-wide-angle lenses. For example, the aperture of common ultra-wide-angle lenses is small, which will cause insufficient light entering the lens and unclear imaging. In addition, aberration correction is difficult and distortion is large. 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, which comprises eight lenses in total, and which includes the following lenses in order from the object side to the imaging surface along the optical axis: The first lens has a negative optical power, the object side surface of which is convex, and the image side surface of which is concave; The second lens has a negative optical power, the object side surface of which is concave at the near optical axis, and the image side surface of which is concave; The third lens has positive power and its object side surface is convex near the optical axis; a fourth lens having positive refractive power, whose object-side surface is concave and whose image-side surface is convex; a fifth lens having positive refractive power, whose object-side surface is convex and whose image-side surface is convex; a sixth lens element having negative optical power, whose image side surface is concave; a seventh lens element having positive refractive power, whose object-side surface is convex and whose image-side surface is convex; The eighth lens has a negative optical power, the object side surface of which is convex at the near optical axis, and the image side surface of which is concave; The total optical length TTL of the optical lens and the aperture value Fno of the optical lens satisfy: 7.8 mm <TTL / Fno<8.5mm。

[0005] Further preferably, the real image height ih corresponding to the maximum half field angle of the optical lens, the effective focal length f of the optical lens and the radian value θ of the maximum half field angle of the optical lens satisfy: 0.96 / rad <ih / (f×θ)<1.04 / rad。

[0006] Further preferably, the true image height ih corresponding to the maximum half field of view angle of the optical lens and the entrance pupil diameter EPD of the optical lens satisfy: 2.6 < ih / EPD < 2.9.

[0007] Further preferably, the effective focal length f of the optical lens and the radian value θ of the maximum half field of view angle of the optical lens satisfy: 0.8 mm / rad < f / θ < 0.87 mm / rad.

[0008] Further preferably, the effective focal length f of the optical lens and the focal length f2 of the second lens satisfy: -3.5 < f2 / f < -2.4.

[0009] Further preferably, the effective focal length f of the optical lens and the combined focal length f1234 of the first lens, the second lens, the third lens and the fourth lens satisfy: 3.2 < f1234 / f < 9.5; the effective focal length f of the optical lens and the combined focal length f5678 of the fifth lens, the sixth lens, the seventh lens and the eighth lens satisfy: 2.2 < f5678 / f < 2.8.

[0010] Further preferably, the combined focal length f1234 of the first lens, the second lens, the third lens and the fourth lens and the combined focal length f5678 of the fifth lens, the sixth lens, the seventh lens and the eighth lens satisfy: 1.2 < f1234 / f5678 < 4.2.

[0011] Further preferably, the curvature radius R15 of the object side surface of the eighth lens and the curvature radius R16 of the image side surface of the eighth lens satisfy: 2.2 < (R15 + R16) / (R15 - R16) < 3.4.

[0012] Further preferably, the clear aperture semi-diameter CSD11 at the object side end of the first lens and the clear aperture semi-diameter CSD81 at the object side end of the eighth lens satisfy: 2.3 < CSD11 / CSD81 < 3.

[0013] Further preferably, the sagitta corresponding to the maximum clear aperture semi-diameter at the image side end of the second lens and the central thickness CT2 of the second lens along the optical axis satisfy: 0.8 < SAGX22 / CT2 < 1.3.

[0014] Compared with the prior art, the optical lens provided by the present invention adopts eight lenses with specific optical powers, and through specific surface shape matching and reasonable optical power distribution, it can improve the imaging quality of the optical lens, reduce aberration, improve the imaging quality of the optical lens, and enable the lens to have one or more advantages such as super wide angle, large aperture, high pixel, large target surface, etc. Description of the Drawings

[0015] The above and / or additional aspects and advantages of the present invention will become apparent and easily understood from the description of the embodiments in conjunction with the following drawings, in which: Figure 1 Schematic diagram of the structure of the optical lens in Example 1 of the present invention.

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

[0017] Figure 3 Graph showing the F-Theta distortion of the optical lens in Example 1 of the present invention.

[0018] Figure 4 Graph showing the axial aberration of the optical lens in Example 1 of the present invention.

[0019] Figure 5 Graph showing the vertical axis chromatic aberration of the optical lens in Example 1 of the present invention.

[0020] Figure 6 Schematic diagram of the structure of the optical lens in Example 2 of the present invention.

[0021] Figure 7 4 is a field curvature curve diagram of the optical lens in Example 2 of the present invention.

[0022] Figure 8 Graph showing the F-Theta distortion of the optical lens in Embodiment 2 of the present invention.

[0023] Fig. 9 Graph showing the axial aberration of the optical lens in Embodiment 2 of the present invention.

[0024] Fig.10 Graph showing the vertical axis chromatic aberration of the optical lens in Example 2 of the present invention.

[0025] Fig.11 Schematic diagram of the structure of the optical lens in Example 3 of the present invention.

[0026] Fig.12 4 is a field curvature curve diagram of the optical lens in Example 3 of the present invention.

[0027] Fig.13 Graph showing the F-Theta distortion of the optical lens in Embodiment 3 of the present invention.

[0028] Fig.14 Graph showing the axial aberration of the optical lens in Embodiment 3 of the present invention.

[0029] Fig.15 Graph showing the vertical axis chromatic aberration of the optical lens in Example 3 of the present invention.

[0030] Fig.16Schematic diagram of the structure of the optical lens in Example 4 of the present invention.

[0031] Fig.17 It is a field curvature curve diagram of the optical lens in Example 4 of the present invention.

[0032] Fig.18 4 is an F-Theta distortion curve of the optical lens in Example 4 of the present invention.

[0033] Fig.19 4 is an axial aberration curve diagram of the optical lens in Example 4 of the present invention.

[0034] Fig. 20 Graph showing the vertical axis chromatic aberration of the optical lens in Example 4 of the present invention.

[0035] The following specific implementation manner will further illustrate the present invention in conjunction with the above-mentioned drawings. DETAILED DESCRIPTION

[0036] In order to better understand the present application, a more detailed description will be made of various aspects of the present application with reference to the accompanying drawings. It should be understood that these detailed descriptions are only descriptions of the 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.

[0037] It should be noted that in this specification, the expressions of first, second, third, etc. are only used to distinguish one feature from another feature, and do not represent any limitation on the features. Therefore, without departing from the teaching of the present invention, the first lens discussed below may also be referred to as the second lens or the third lens.

[0038] In the drawings, the thickness, size and shape of the lenses have been slightly exaggerated for ease of explanation. Specifically, the shapes of the spherical or aspherical surfaces shown in the drawings are shown by way of example. That is, the shapes of the spherical or aspherical surfaces are not limited to the shapes of the spherical or aspherical surfaces shown in the drawings. The drawings are only examples and are not drawn strictly to scale.

[0039] In this article, the paraxial region refers to the region near the optical axis. If the lens surface is convex and the position of the convex surface 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 position of the concave surface 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 object is called the object side of the lens, and the surface of each lens closest to the imaging plane is called the image side of the lens.

[0040] 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 exclude 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 listed 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.

[0041] Unless otherwise defined, all terms (including technical terms and scientific terms) used in this article have the same meaning as commonly understood by ordinary technicians in the field to which this application belongs. It should also be understood that terms (such as terms defined in commonly used dictionaries) should be interpreted as having the same meaning as their meaning in the context of the relevant technology, and will not be interpreted in an idealized or overly formal sense unless explicitly defined in this article.

[0042] It should be noted that, in the absence of conflict, the embodiments and features in the embodiments of the present 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.

[0043] The optical lens provided by the embodiment of the present invention comprises eight lenses in total, and the optical lens comprises, in order from the object side to the imaging surface along the optical axis: a first lens, a second lens, a third lens, a fourth lens, a fifth lens, a sixth lens, a seventh lens and an eighth lens.

[0044] In some embodiments, the first lens may have a negative optical power, and its object side surface is convex, and its image side surface is concave. The second lens may have a negative optical power, and its object side surface is concave at the near optical axis, and its image side surface is concave. The third lens may have a positive optical power, and its object side surface is convex at the near optical axis, and its image side surface may be concave or convex. The fourth lens may have a positive optical power, and its object side surface is concave, and its image side surface is convex. The fifth lens may have a positive optical power, and its object side surface is convex, and its image side surface is convex. The sixth lens may have a negative optical power, and its object side surface may be concave or convex, and its image side surface is concave. The seventh lens may have a positive optical power, and its object side surface is convex, and its image side surface is convex. The eighth lens may have a negative optical power, and its object side surface is convex at the near optical axis, and its image side surface is concave.

[0045] In some embodiments, the optical lens may further include an aperture, and the aperture may be located between the fourth lens and the fifth lens. It is understood that the aperture is used to limit the amount of light entering to change the brightness of the image. When the aperture is located between the fourth lens and the fifth lens, it is convenient to correct the aperture aberration.

[0046] 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.

[0047] In some embodiments, the total optical length TTL of the optical lens and the aperture value Fno of the optical lens satisfy: 7.8mm < TTL / Fno < 8.5mm. By satisfying the above conditional formula and controlling the relationship between the total length and the aperture value of the optical lens, it is ensured that the optical lens can meet the requirements of large aperture and miniaturization design, and provide sufficient light transmission for camera shooting to meet the needs of high-quality and high-definition shooting.

[0048] In some embodiments, the true image height ih corresponding to the maximum half field of view angle of the optical lens, the effective focal length f of the optical lens, and the radian value θ of the maximum half field of view angle of the optical lens satisfy: 0.96 / rad < ih / (f×θ) < 1.04 / rad. By satisfying the above conditional formula, it is possible to control the optical lens to have small distortion and improve the imaging quality of the optical lens.

[0049] In some embodiments, the true image height ih corresponding to the maximum half field of view angle of the optical lens and the entrance pupil diameter EPD of the optical lens satisfy: 2.6 < ih / EPD < 2.9. By satisfying the above conditional formula, the optical lens can have a larger entrance pupil diameter and higher light transmission, thereby increasing the imaging effect when the optical lens works in a dark environment and reducing the aberration of the edge field of view.

[0050] In some embodiments, the effective focal length f of the optical lens and the radian value θ of the maximum half field of view angle of the optical lens satisfy: 0.8mm / rad < f / θ < 0.87mm / rad. By satisfying the above conditional formula, while the optical lens has sufficient focal length, it has a large field of view angle to meet the requirements of the shooting range, which is beneficial to reducing the deflection angle of light, thus better balancing the aberration of the optical lens and being beneficial to compressing the length of the optical lens in the optical axis direction.

[0051] In some embodiments, the effective focal length f of the optical lens and the focal length f2 of the second lens satisfy: -3.5 < f2 / f < -2.4. By satisfying the above conditional formula, the second lens has the effect of diverging light. At the same field of view angle, the light emerging from the image side of the first lens is further diverged, and the central light and the edge light of each field of view can be dispersed. It can enable the rear optical system to have a larger light receiving surface to receive the light emerging from the image side of the second lens, realizing a larger light input, which is beneficial to increasing the relative illumination.

[0052] In some embodiments, the effective focal length f of the optical lens and the combined focal length f1234 of the first lens, the second lens, the third lens, and the fourth lens satisfy: 3.2 < f1234 / f < 9.5. By satisfying the above conditional formula, by setting the front diaphragm lens group to have a large refractive power, it is beneficial for large-angle light to enter the optical lens to achieve a large field of view angle of the optical lens, and it is also beneficial to increase the light flux of the optical lens and better achieve a large aperture of the optical lens.

[0053] In some embodiments, the effective focal length f of the optical lens and the combined focal length f5678 of the fifth lens, the sixth lens, the seventh lens, and the eighth lens satisfy: 2.2 < f5678 / f < 2.8. By satisfying the above conditional formula, by reasonably setting the positive refractive power of the rear diaphragm lens group, it is beneficial to balance the distortion and astigmatism generated by the front-end lens of the optical lens and improve the imaging quality of the optical lens.

[0054] In some embodiments, the combined focal length f1234 of the first lens, the second lens, the third lens, and the fourth lens and the combined focal length f5678 of the fifth lens, the sixth lens, the seventh lens, and the eighth lens satisfy: 1.2 < f1234 / f5678 < 4.2. By satisfying the above conditional formula, by reasonably setting the focal length relationship of each lens group before and after the diaphragm, while the lens has a large field of view angle, various aberrations of the optical lens can be corrected, and the imaging quality of the optical lens can be improved.

[0055] In some embodiments, the object-side curvature radius R15 of the eighth lens and the image-side curvature radius R16 of the eighth lens satisfy: 2.2 < (R15 + R16) / (R15 - R16) < 3.4. By satisfying the above conditional formula, the ability of the eighth lens to converge light is reduced, which can stably irradiate light onto the imaging surface, and at the same time enable more peripheral light to reach the imaging surface, improving the illuminance and light transmission of the optical lens field of view and reducing the sensitivity of the lens.

[0056] In some embodiments, the object-side clear aperture semi-diameter CSD11 of the first lens and the object-side clear aperture semi-diameter CSD81 of the eighth lens satisfy: 2.3 < CSD11 / CSD81 < 3. By satisfying the above conditional formula, the optical lens has a large aperture, which can better collect large-angle light, achieve ultra-wide-angle imaging of the optical lens, and at the same time can increase the imaging area of the optical lens and achieve large-target-surface imaging of the optical lens.

[0057] In some embodiments, the sagitta corresponding to the maximum clear aperture semi-diameter at the image side end of the second lens and the central thickness CT2 of the second lens along the optical axis satisfy: 0.8 < SAGX22 / CT2 < 1.3. By satisfying the above conditional formula, the surface shape of the second lens can be reasonably controlled, which is beneficial to reducing the deflection angle of light in the optical lens, thereby reducing the sensitivity of the marginal light of the optical lens and improving the resolution.

[0058] In some embodiments, the true image height ih corresponding to the maximum half field of view angle of the optical lens and the effective focal length f of the optical lens satisfy: 1.8 < ih / f < 1.9. Satisfying the above conditional formula and controlling the image height and focal length of the optical lens within a reasonable range helps the optical lens to have the characteristic of a large image plane, while improving the resolution of the optical lens and the imaging quality.

[0059] In some embodiments, the sum ∑CT of the central thicknesses of the first lens to the eighth lens along the optical axis and the total optical length TTL of the optical lens satisfy: 0.55 < ΣCT / TTL < 0.65. Satisfying the above conditional formula and reasonably configuring the total optical length of the optical lens and the sum of the thicknesses of each lens helps to achieve the characteristic of high pixels and improve the imaging quality of the optical lens.

[0060] In some embodiments, the central thickness CT7 of the seventh lens along the optical axis and the edge thickness ET7 of the seventh lens satisfy: 2.6 < CT7 / ET7 < 3. Satisfying the above conditional formula and controlling the thickness ratio of the seventh lens within a certain range, the seventh lens will not be locally too thick, which is beneficial to the processing and forming of the lens, thus facilitating the reduction of the assembly difficulty, and the surface curvature change of the seventh lens is reasonable, which can effectively correct the field curvature of the system.

[0061] In some embodiments, the central thickness CT8 of the eighth lens along the optical axis and the edge thickness ET8 of the eighth lens satisfy: 0.4 < CT8 / ET8 < 0.6. Satisfying the above conditional formula and reasonably restricting the central thickness and edge thickness of the eighth lens ensure that the last lens is not easily deformed during the assembly process, which is very helpful for the stability of the field curvature, and the forming and debugging process space is larger, avoiding the risk of stray light caused by appearance problems of the eighth lens, and at the same time, it can better balance the distortion and astigmatism of the entire optical lens.

[0062] In some embodiments, 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: 1.8 < (R1 + R2) / (R1 - R2) < 2.1. Satisfying the above conditional formula can make the object side surface and the image side surface close to a concentric circle structure, reduce the light converging ability of the first lens, and play a role in smoothly transitioning the light.

[0063] In some embodiments, 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: -0.5 < f1 / (R1 + R2) < -0.4. Satisfying the above conditional formula can constrain the surface shapes of the object side surface and the image side surface of the first lens, which is beneficial to reducing the bending degree of the light at the image side surface of the first lens, reducing the astigmatism amount of the optical system, ensuring that the optical lens has a large field of view angle and small distortion, and further improving the imaging quality.

[0064] In some embodiments, the radius of curvature R1 of the object side surface of the first lens and the sagitta SAGX11 corresponding to the maximum clear aperture radius at the object side end of the first lens satisfy: 5.1 < R1 / SAGX11 < 6.3. By satisfying the above conditional formula, the ratio relationship between the radius of curvature of the object side surface of the first lens and the sagitta at the maximum effective aperture can be controlled, providing a negative refractive power for the optical lens, thereby capturing the light rays entering the optical lens at large angles and expanding the field of view angle range of the optical lens.

[0065] In some embodiments, the optical lens satisfies the conditional formula: 1.5 mm < f < 1.6 mm, 210° ≤ FOV ≤ 220°, 1 mm < EPD < 1.2 mm; 1.4 < Fno < 1.6; 2.9 mm < ih < 3 mm; where f represents the effective focal length of the optical lens, TTL represents the total optical length of the optical lens, FOV represents the maximum field of view angle of the optical lens, EPD represents the entrance pupil diameter of the optical lens, Fno represents the f-number of the optical lens, and ih represents the true image height corresponding to the maximum half field of view angle of the optical lens. By satisfying the above conditional formula, the optical lens has at least one or more advantages of ultra-wide angle, large aperture, high pixel, and large target surface characteristics.

[0066] In some embodiments, the eight lenses in the optical lens can all 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. Specifically, the first lens and the fourth lens can be made of glass lenses, and the second lens, the third 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 improve the thermal stability performance, effectively reduce costs, correct aberrations, reduce the volume, and provide an optical lens product with higher cost performance.

[0067] In some example 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, in the optical lens provided by the present invention, the first lens and the fourth lens can adopt spherical lenses, and the second lens, the third lens, the fifth lens, the sixth lens, the seventh lens, and the eighth lens can adopt aspherical lenses.

[0068] In various embodiments 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 equations: ; Among them, 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 surface vertex, K is the quadratic surface coefficient, B, C, D, E, F, G, and H are the fourth-order, sixth-order, eighth-order, tenth-order, twelfth-order, fourteenth-order, and sixteenth-order surface coefficients respectively.

[0069] The present invention is further described below in multiple 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 table of each embodiment. The following embodiments are only preferred embodiments of the present invention, but the embodiments of the present invention are not limited to the following embodiments. Any other changes, substitutions, combinations or simplifications that do not deviate from the innovative points of the present invention should be regarded as equivalent replacement methods and are included in the protection scope of the present invention.

[0070] Example 1 See also Figure 1 , shown is a schematic diagram of the structure of the optical lens 100 provided in Example 1 of the present invention, and the optical lens 100 includes, in sequence from the object side to the imaging surface S19 along the optical axis: a first lens L1, a second lens L2, a third lens L3, a fourth lens L4, an aperture ST, a fifth lens L5, a sixth lens L6, a seventh lens L7, an eighth lens L8 and a filter G1.

[0071] The first lens L1 has negative refractive power, its object side surface S1 is convex, and its image side surface S2 is concave; The second lens L2 has negative refractive power, its object side surface S3 is concave at the near optical axis, and its image side surface S4 is concave; The third lens L3 has positive refractive power, its object side surface S5 is convex at the near optical axis, and its image side surface S6 is concave; The fourth lens L4 has positive refractive power, its object-side surface S7 is concave, and its image-side surface S8 is convex; The fifth lens L5 has positive refractive power, its object-side surface S9 is convex, and its image-side surface S10 is convex; The sixth lens L6 has negative refractive power, its object-side surface S11 is concave, and its image-side surface S12 is concave; The seventh lens L7 has positive refractive power, its object-side surface S13 is convex, and its image-side surface S14 is convex; The eighth lens L8 has negative refractive power, its object-side surface S15 is convex at the near optical axis, and its image-side surface S16 is concave; The object side surface S17 and the image side surface S18 of the filter G1 are both planes; The imaging surface S19 is a plane.

[0072] The first lens L1 and the fourth lens L4 are glass spherical lenses; the second lens L2, the third lens L3, the fifth lens L5, the sixth lens L6, the seventh lens L7 and the eighth lens L8 are plastic aspherical lenses.

[0073] The relevant parameters of each lens in the optical lens 100 in Example 1 are shown in Table 1-1.

[0074] Table 1-1 The surface parameters of the aspheric lens of the optical lens 100 in Example 1 are shown in Table 1-2.

[0075] Table 1-2 In this embodiment, the field curvature curve, F-Theta distortion curve, axial aberration curve, and vertical axis chromatic aberration curve of the optical lens 100 are respectively as follows: Figure 2 , Figure 3 , Figure 4 and Figure 5 shown.

[0076] Figure 2 The field curvature curve in this embodiment is shown, which represents the field curvature of light on 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: °). It can be seen from the figure that the field curvature of the meridional image plane and the sagittal image plane is controlled within ±0.05mm, indicating that the optical lens 100 can well correct the field curvature.

[0077] Figure 3 The F-Theta distortion curve of this embodiment is shown, which represents the distortion of different field angles on the imaging plane, the horizontal axis represents the distortion value (unit: %), and the vertical axis represents the half field angle (unit: °). It can be seen from the figure that the distortion value is controlled within -2%~9%, indicating that the optical lens 100 can correct the distortion well.

[0078] Figure 4 The axial aberration curve in this embodiment is shown, which represents 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. It can be seen from the figure that the offset of the axial aberration is controlled within ±0.02mm, indicating that the optical lens 100 can better correct the axial aberration.

[0079] Figure 5The vertical chromatic aberration curve in this embodiment is shown, which represents the chromatic aberration of each wavelength relative to the central wavelength (0.555 μm) at different image heights on the imaging surface, 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 angle. It can be seen from the figure that the vertical chromatic aberration of the longest wavelength and the shortest wavelength is controlled within 0~4 μm, indicating that the optical lens 100 can well correct the vertical chromatic aberration.

[0080] Example 2 See also Figure 6 , shown is a schematic diagram of the structure of the optical lens 200 provided in Example 2 of the present invention. Compared with Example 1, the main difference between this embodiment and Example 1 is that the optical parameters such as the curvature radius of each lens surface and the lens thickness are different.

[0081] The relevant parameters of each lens in the optical lens 200 in Example 2 are shown in Table 2-1.

[0082] Table 2-1 The surface parameters of the aspheric lens of the optical lens 200 in Example 2 are shown in Table 2-2.

[0083] Table 2-2 In this embodiment, the field curvature curve, F-Theta distortion curve, axial aberration curve, and vertical axis chromatic aberration curve of the optical lens 200 are respectively as follows: Figure 7 , Figure 8 , Fig. 9 and Fig.10 shown.

[0084] from Figure 7 It can be seen that the field curvature of the meridian image plane and the sagittal image plane is controlled within ±0.05mm, indicating that the optical lens 200 can correct the field curvature well.

[0085] from Figure 8 It can be seen that the distortion value is controlled within -4%~10%, indicating that the optical lens 200 can correct the distortion well.

[0086] from Fig. 9 It can be seen that the offset of the axial aberration is controlled within -0.04mm~0.02mm, which means that the optical lens 200 can correct the axial aberration well.

[0087] from Fig.10 It can be seen that the vertical axis chromatic aberration of the longest wavelength and the shortest wavelength is controlled within -2μm~5μm, indicating that the optical lens 200 can correct the vertical axis chromatic aberration well.

[0088] Example 3 See also Fig.11 , shown is a schematic diagram of the structure of the optical lens 300 provided in Example 3 of the present invention. Compared with Example 1, the main differences of this embodiment are: the object side surface S11 of the sixth lens L6 is convex at the near optical axis; the optical parameters such as the curvature radius of each lens surface and the lens thickness 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 parameters of the aspheric 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-Theta distortion curve, axial aberration curve, and vertical chromatic aberration curve of the optical lens 300 are respectively as follows: Fig.12 , Fig.13 , Fig.14 and Fig.15 shown.

[0092] from Fig.12 It can be seen that the field curvature of the meridian image plane and the sagittal image plane is controlled within ±0.05mm, indicating that the optical lens 300 can correct the field curvature well.

[0093] from Fig.13 It can be seen that the distortion value is controlled within -3%~10%, indicating that the optical lens 300 can correct the distortion well.

[0094] from Fig.14 It can be seen that the offset of the axial aberration is controlled within ±0.03 mm, indicating that the optical lens 300 can correct the axial aberration well.

[0095] from Fig.15 It can be seen that the vertical axis chromatic aberration of the longest wavelength and the shortest wavelength is controlled within ±4 μm, indicating that the optical lens 300 can correct the vertical axis chromatic aberration well.

[0096] Example 4 See also Fig.16 , shown is a schematic diagram of the structure of an optical lens 400 provided in Example 4 of the present invention. Compared with Example 1, the main differences of this embodiment are: the image side surface S6 of the third lens L3 is a convex surface; the optical parameters such as the curvature radius of each lens surface and the lens thickness are different.

[0097] The relevant parameters of each lens in the optical lens 400 in Example 4 are shown in Table 4-1.

[0098] Table 4-1 The surface parameters of the aspheric lens of the optical lens 400 in Example 4 are shown in Table 4-2.

[0099] Table 4-2 In this embodiment, the field curvature curve, F-Theta distortion curve, axial aberration curve, and vertical axis chromatic aberration curve of the optical lens 400 are respectively as follows: Fig.17 , Fig.18 , Fig.19 and Fig. 20 shown.

[0100] from Fig.17 It can be seen that the field curvature of the meridian image plane and the sagittal image plane is controlled within ±0.05mm, indicating that the optical lens 400 can correct the field curvature well.

[0101] from Fig.18 It can be seen that the distortion value is controlled within 0~10%, indicating that the optical lens 400 can correct the distortion well.

[0102] from Fig.19 It can be seen that the offset of the axial aberration is controlled within -0.03mm~0.01mm, which means that the optical lens 400 can correct the axial aberration well.

[0103] from Fig. 20 It can be seen that the vertical axis chromatic aberration of the longest wavelength and the shortest wavelength is controlled within 0~4μm, which means that the optical lens 400 can correct the vertical axis chromatic aberration well.

[0104] Please refer to Table 5, which shows the optical characteristics corresponding to the above embodiments, including the effective focal length f of the optical lens, the total optical length TTL, the aperture value Fno, the real image height ih (half image height) corresponding to the maximum half field of view angle, the chief ray incident angle CRA at the maximum image height, the maximum field of view FOV, and the numerical value corresponding to each conditional expression in each embodiment.

[0105] Table 5 Compared with the prior art, the optical lens provided by the present invention has at least the following advantages: (1) The optical lens provided by the present invention has a large aperture through a specific surface shape setting and a reasonable optical focal length distribution, so that high-definition imaging can be achieved even in a dark environment; an ultra-wide angle of the lens can be achieved, thereby obtaining more scene information and meeting the needs of large-range detection of the optical lens.

[0106] (2) The optical lens provided by the present invention has a large image surface, which can be well matched with a large-size chip to ensure good resolution quality; at the same time, it can also reasonably correct the overall aberration of the optical lens, so that the optical lens has small distortion and high pixels, thereby improving the imaging quality of the optical lens.

[0107] (3) The optical lens provided by the present invention adopts a glass-plastic hybrid structure, which not only makes the lens have good thermal stability, improves the stability of the lens under high and low temperature conditions, but also improves the imaging quality. It also greatly reduces the production cost of the lens, reduces the size of the lens, and better realizes the miniaturization of the lens.

[0108] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "examples", "specific examples", or "some examples" means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner.

[0109] The above-mentioned embodiments only express several implementation methods of the present invention, and the description thereof is relatively specific and detailed, but it cannot be understood as limiting the scope of the patent of the present invention. It should be pointed out that, for ordinary technicians in this field, several variations and improvements can be made without departing from the concept of the present invention, which all belong to the protection scope of the present invention. Therefore, the protection scope of the patent of the present invention shall be subject to the attached claims.

Claims

1. An optical lens, comprising eight lenses, characterized in that: From the object side to the imaging plane along the optical axis, it successively includes: 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 near the optical axis and whose image side is concave; A third lens with a positive optical power, whose object side is convex near the optical axis; A fourth lens with a positive optical power, whose object side is concave and whose image side is convex; A fifth lens with a positive optical power, whose object side is convex and whose image side is convex; A sixth lens with a negative optical power, whose image side is concave; A seventh lens with a positive optical power, whose object side is convex and whose image side is convex; An eighth lens with a negative optical power, whose object side is convex near the optical axis and whose image side is concave; Wherein, the total optical length TTL of the optical lens and the aperture value Fno of the optical lens satisfy: 7.8mm < TTL / Fno < 8.5mm.

2. The optical lens according to claim 1, characterized in that: The true image height ih corresponding to the maximum half field of view angle of the optical lens, the effective focal length f of the optical lens and the radian value θ of the maximum half field of view angle of the optical lens satisfy: 0.96 / rad < ih / (f×θ) < 1.04 / rad.

3. The optical lens according to claim 1, characterized in that: The true image height ih corresponding to the maximum half field of view angle of the optical lens and the entrance pupil diameter EPD of the optical lens satisfy: 2.6 < ih / EPD < 2.

9.

4. The optical lens according to claim 1, characterized in that: The effective focal length f of the optical lens and the radian value θ of the maximum half field of view angle of the optical lens satisfy: 0.8mm / rad < f / θ < 0.87mm / rad.

5. The optical lens according to claim 1, characterized in that: The effective focal length f of the optical lens and the focal length f2 of the second lens satisfy: -3.5 < f2 / f < -2.

4.

6. The optical lens according to claim 1, characterized in that: The effective focal length f of the optical lens and the combined focal length f1234 of the first lens, the second lens, the third lens and the fourth lens satisfy: 3.2 < f1234 / f < 9.5; The effective focal length f of the optical lens and the combined focal length f5678 of the fifth lens, the sixth lens, the seventh lens and the eighth lens satisfy: 2.2 < f5678 / f < 2.

8.

7. The optical lens according to claim 1, characterized in that: The combined focal length f1234 of the first lens, the second lens, the third lens and the fourth lens and the combined focal length f5678 of the fifth lens, the sixth lens, the seventh lens and the eighth lens satisfy: 1.2 < f1234 / f5678 < 4.

2.

8. The optical lens according to claim 1, characterized in that: The curvature radius R15 of the object side of the eighth lens and the curvature radius R16 of the image side of the eighth lens satisfy: 2.2 < (R15+R16) / (R15-R16) < 3.

4.

9. The optical lens according to claim 1, characterized in that: The clear aperture semi-diameter CSD11 at the object side end of the first lens and the clear aperture semi-diameter CSD81 at the object side end of the eighth lens satisfy: 2.3 < CSD11 / CSD81 < 3.

10. The optical lens according to claim 1, characterized in that: The sagitta corresponding to the maximum clear aperture semi-diameter at the image side end of the second lens and the central thickness CT2 of the second lens along the optical axis satisfy: 0.8 < SAGX22 / CT2 < 1.3.

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