Optical lens

Abstract

The invention provides an optical lens, which comprises nine lenses from an object side to an imaging surface along an optical axis: a first lens with negative focal power, a second lens with negative focal power, a third lens with negative focal power, a fourth lens with negative focal power, a fifth lens with negative focal power and a sixth lens with negative focal power, the object side surface of the second lens is a convex surface, and the image side surface of the second lens is a concave surface; the object side surface of the third lens is a convex surface, and the image side surface of the third lens is a concave surface; 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; the seventh lens has positive focal power; the eighth lens has negative focal power; and the ninth lens has positive focal power. According to the optical lens provided by the invention, through specific surface shape matching and reasonable focal power distribution, the lens has one or more advantages of short focus, miniaturization, large field angle, large aperture, large target surface, low distortion and low sensitivity.

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, automotive, meteorology, medical, VR, AR and other fields, the requirements for the field of view of the lenses they carry are becoming increasingly higher. Wide-angle lenses introduce barrel distortion to compress the light at the edge of the field of view as much as possible, thus achieving ultra-wide-angle lenses. Currently, ultra-wide-angle lenses still have many problems. For example, the aperture of common ultra-wide-angle lenses is relatively small, resulting in insufficient light entering the lens and unclear images in dark environments. In addition, there are problems such as difficulty in correcting aberrations, large distortion, and loss of focus in high and low temperature environments. 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, comprising nine lenses, which include 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, its object-side surface is convex and its image-side surface is concave; a second lens having positive refractive power, whose object-side surface is convex and whose image-side surface is concave; a third lens element having positive optical power, whose object-side surface is convex and whose image-side surface is concave; a fourth lens element having positive refractive power, whose object-side surface is concave and whose image-side surface is convex; a fifth lens element having positive refractive power, whose object-side surface and image-side surface are convex; a sixth lens element having negative optical power and a concave image-side surface; a seventh lens element having positive refractive power, whose object-side surface and image-side surface are convex; an eighth lens having negative optical power; The ninth lens element has positive refractive power, its object-side surface is convex near the optical axis, and its image-side surface is concave near the optical axis; The total optical length TTL of the optical lens and the aperture value Fno of the optical lens satisfy: 7.5mm <TTL / Fno<9.1mm。

[0005] Further preferably, the total optical length TTL of the optical lens and the effective focal length f of the optical lens satisfy: 5.2 <TTL / f<8.2。

[0006] Further preferably, the focal length f2 of the second lens, the focal length f3 of the third lens, the focal length f4 of the fourth lens, the focal length f5 of the fifth lens and the effective focal length f of the optical lens satisfy: 19<(f2+f3+f4+f5) / f<42.

[0007] Further preferably, the total optical length TTL of the optical lens, the center thickness CT4 of the fourth lens, the center thickness CT5 of the fifth lens and the center thickness CT6 of the sixth lens meet the following conditions: 2.8 <TTL / (CT4+CT5+CT6)<5.4。

[0008] Further preferably, the half-aperture sag height SAG81 of the object side light passing through the eighth lens and the half-aperture sag height SAG82 of the image side light passing through the eighth lens satisfy: -27 <SAG81 / SAG82<-9。

[0009] Further preferably, a curvature radius R1 of the object side surface of the first lens and a curvature radius R2 of the image side surface of the first lens satisfy: 0.6<(R1-R2) / (R1+R2)<0.8.

[0010] Further preferably, the image side light semi-aperture CSD92 of the ninth lens and the image side light semi-aperture sag SAG92 of the ninth lens satisfy: -9.3 <CSD92 / SAG92<-3.5。

[0011] Further preferably, the focal length f1 of the first lens and the effective focal length f of the optical lens satisfy: -2.9 <f1 / f<-2。

[0012] Further preferably, the focal length f6 of the sixth lens and the effective focal length f of the optical lens satisfy: <f6 / f<-1.5。

[0013] Further preferably, the focal length f7 of the seventh lens and the effective focal length f of the optical lens satisfy: 1.6 <f7 / f<2.7。

[0014] Compared with the existing technology, the optical lens provided by the present invention uses nine lenses with specific optical powers. Through specific surface shape matching 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 of short focus, miniaturization, large field of view, large aperture, large target surface, low distortion, and low sensitivity. BRIEF DESCRIPTION OF THE DRAWINGS

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

[0016] Figure 2 Graph showing the F-Theta distortion of the optical lens in Example 1 of the present invention.

[0017] Figure 3 Graph showing the field curvature of the optical lens in Example 1 of the present invention.

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

[0019] Figure 5 Schematic diagram of the structure of the optical lens in Example 2 of the present invention.

[0020] Figure 6 Graph showing the F-Theta distortion of the optical lens in Example 2 of the present invention.

[0021] Figure 7 Graph showing the field curvature of the optical lens in Example 2 of the present invention.

[0022] Figure 8 Graph showing vertical axis chromatic aberration of the optical lens in Example 2 of the present invention.

[0023] Figure 9 Schematic diagram of the structure of the optical lens in Example 3 of the present invention.

[0024] Figure 10 Graph showing the F-Theta distortion of the optical lens in Example 3 of the present invention.

[0025] Figure 11 4 is a field curvature curve diagram of the optical lens in Example 3 of the present invention.

[0026] Figure 12 Graph showing vertical axis chromatic aberration of the optical lens in Example 3 of the present invention.

[0027] The following specific embodiments will further illustrate the present invention in conjunction with the above-mentioned drawings. DETAILED DESCRIPTION

[0028] 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.

[0029] 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.

[0030] 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.

[0031] 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.

[0032] 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.

[0033] 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.

[0034] 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.

[0035] The optical lens provided by the embodiment of the present invention comprises a total of nine lenses. The optical lens sequentially includes: a first lens, a second lens, a third lens, a fourth lens, a fifth lens, a sixth lens, a seventh lens, an eighth lens, and a ninth lens along the optical axis from the object side to the imaging surface.

[0036] In some embodiments, the first lens may have a negative optical power, with its object side being convex and its image side being concave. The second lens may have a positive optical power, with its object side being convex and its image side being concave. The third lens may have a positive optical power, with its object side being convex and its image side being concave. The fourth lens may have a positive optical power, with its object side being concave and its image side being convex. The fifth lens may have a positive optical power, with its object side being convex and its image side being convex. The sixth lens may have a negative optical power, and its object side may be concave or convex, and its image side is concave. The seventh lens may have a positive optical power, with its object side being convex and its image side being convex. The eighth lens may have a negative optical power, and its object side may be concave or convex, and its image side may be concave or convex. The ninth lens may have a positive optical power, with its object side being convex near the optical axis and its image side being concave near the optical axis.

[0037] 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 can be understood that the aperture is used to limit the amount of incident light to change the brightness of the image. When the aperture is located between the fourth lens and the fifth lens, it is convenient for correcting the aperture aberration.

[0038] In some embodiments, the optical lens may further include a filter, and the filter is disposed between the ninth 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.

[0039] In some embodiments, the total optical length TTL of the optical lens and the aperture value Fno of the optical lens satisfy: 7.5mm < TTL / Fno < 9.1mm. By satisfying the above conditional formula, by 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, enabling the optical lens to obtain sufficient light transmission in a dim environment and meet the needs of high-quality and high-definition shooting.

[0040] In some embodiments, the total optical length TTL of the optical lens and the effective focal length f of the optical lens satisfy: 5.2 < TTL / f < 8.2. By satisfying the above conditional formula, the ratio of the total optical length to the effective focal length of the optical lens can be reasonably configured, which is beneficial to the miniaturization design of the optical lens. At the same time, it is also beneficial for the optical lens to have a reasonable field angle range while achieving certain focal length characteristics, thereby meeting the wide-angle design of the optical lens and enabling the optical lens to obtain sufficient object-side space information.

[0041] In some embodiments, the focal length f2 of the second lens, the focal length f3 of the third lens, the focal length f4 of the fourth lens, the focal length f5 of the fifth lens and the effective focal length f of the optical lens satisfy: 19 < (f2 + f3 + f4 + f5) / f < 42. By satisfying the above conditional formula, setting the second lens to the fifth lens to have positive optical power can reduce the light deflection pressure of each lens, enlarge the aperture of the optical lens, and significantly shorten the total length of the optical lens, meeting the miniaturization design requirements; it can also effectively control the depth of field of the optical lens, enabling the optical lens to achieve clear imaging at different object distances.

[0042] In some embodiments, the overall optical length TTL of the optical lens, the central thickness CT4 of the fourth lens, the central thickness CT5 of the fifth lens and the central thickness CT6 of the sixth lens satisfy: 2.8 < TTL / (CT4 + CT5 + CT6) < 5.4. By satisfying the above conditional formula, the relationship between the total length of the optical lens and the image height can be effectively controlled, and it can ensure that the thickness tolerance of the optical lens has a low sensitivity, improving the assembly yield of the optical lens.

[0043] In some embodiments, the object-side clear aperture sag SAG81 and the image-side clear aperture sag SAG82 of the eighth lens satisfy: -27 < SAG81 / SAG82 < -9. By satisfying the above conditional formula, by controlling the ratio of the sags of the object side and the image side of the eighth lens within a reasonable range, the shape of the eighth lens can be better controlled, which is beneficial to minimizing chromatic aberration and spherical aberration to the greatest extent, improving the imaging quality of the optical lens, and is also beneficial to the molding and processing of the eighth lens.

[0044] In some embodiments, the object-side curvature radius R1 and the image-side curvature radius R2 of the first lens satisfy: 0.6 < (R1 - R2) / (R1 + R2) < 0.8. By satisfying the above conditional formula, the surface shape and aperture of the first lens are reasonably configured, which is beneficial to increasing the central thickness of the first lens, and then providing sufficient optical path deflection space for large-angle incident light, facilitating the gentle convergence of the large-angle incident light within the first lens, and thus effectively controlling the generation of spherical aberration.

[0045] In some embodiments, the image-side clear aperture CSD?? and the image-side clear aperture sag SAG92 of the ninth lens satisfy: -9.3 < CSD92 / SAG92 < -3.5. By satisfying the above conditional formula, it is beneficial to control the surface shape of the edge field of the ninth lens, improve the correction ability of various aberrations of the edge field light, and thus improve the imaging quality of the edge field of the optical lens.

[0046] In some embodiments, the focal length f1 of the first lens and the effective focal length f of the optical lens satisfy: -2.9 < f1 / f < -2. By satisfying the above conditional formula, setting the first lens of the optical lens as a lens with a negative optical power can capture the light rays incident on the optical lens at a large angle, expand the field angle range of the optical lens, and at the same time is beneficial to reducing the sensitivity of the optical lens and realizing the miniaturized design of the optical lens.

[0047] In some embodiments, the focal length f6 of the sixth lens and the effective focal length f of the optical lens satisfy: -2 < f6 / f < -1.5. By satisfying the above conditional formula, reasonably controlling the focal length value of the sixth lens can slowly lift the large field light, change the parallel light trend of the light beam into a divergent trend, which is beneficial to controlling the back focal length of the lens and is beneficial to realizing a large target surface and reducing the principal ray angle.

[0048] In some embodiments, the focal length f7 of the seventh lens and the effective focal length f of the optical lens satisfy: 1.6 < f7 / f < 2.7. By satisfying the above conditional formula, reasonably controlling the focal length value of the seventh lens can make the light ray trend gentle, which is beneficial to the divergence of the light rays while realizing the apochromatic function, and is beneficial to ensuring the tolerance performance.

[0049] In some embodiments, the focal length f8 of the eighth lens and the effective focal length f of the optical lens satisfy: -5.3 < f8 / f < -3.7. By satisfying the above conditional formula, it is beneficial to expand the width of the light beam, so that the width of the light beam at a larger angle expands after passing through the first lens to the seventh lens, and the wide light beam fully enters the imaging surface of the optical lens, so that the optical lens has a wider field range and is beneficial to realizing high-pixel imaging.

[0050] In some embodiments, the focal length f9 of the ninth lens and the effective focal length f of the optical lens satisfy: 3 < f9 / f < 4.2. By satisfying the above conditional formula, reasonably controlling the focal length value of the ninth lens can change the divergent trend of the light beam into a focusing trend, reduce the optical path, reduce the aperture of the subsequent lens, and is beneficial to realizing a miniaturized volume and a real-time athermalization function.

[0051] In some embodiments, the maximum field angle FOV of the optical lens and the aperture value Fno of the optical lens satisfy: 85° < FOV / Fno < 135°. By satisfying the above conditional formula, it can ensure that the optical lens meets a certain large field angle, reduce the influence of off-axis aberration on the system, and at the same time ensure the improvement of the imaging surface brightness, thereby improving the imaging quality.

[0052] In some embodiments, the clear aperture semi-diameter CSD11 of the object side surface of the first lens and the clear aperture semi-diameter CSD81 of the object side surface of the eighth lens satisfy: 3.6 < CSD11 / CSD81 < 5.5. Meeting the above conditional formula enables the optical lens to have a relatively large aperture, better achieve large-angle light collection, realize the ultra-wide-angle imaging of the optical lens, and at the same time increase the imaging area of the optical lens to achieve large-format imaging of the optical lens.

[0053] In some embodiments, the radius of curvature R1 of the object side surface of the first lens and the sagittal height SAG11 of the clear aperture semi-diameter of the object side surface of the first lens satisfy: 10 < R1 / SAG11 < 14. Meeting the above conditional formula can control the ratio relationship between the radius of curvature of the object side surface of the first lens and the sagittal height at the maximum effective aperture, provide negative refractive power for the optical lens, thereby capturing the light rays entering the optical lens at large angles and expanding the field angle range of the optical lens.

[0054] In some embodiments, the optical lens satisfies the following conditional formula: 1.7 mm < f < 2.5 mm; 160° < FOV < 210°; 0.9 mm < EPD < 1.6 mm; 12 mm < TTL < 15 mm; 1.5 < Fno < 1.9; 5.1 mm < IH < 6.6 mm; where f represents the effective focal length of the optical lens, FOV represents the maximum field angle of the optical lens, EPD represents the entrance pupil diameter of the optical lens, TTL represents the total optical length of the optical lens, Fno represents the f-number of the optical lens, and IH represents the image height corresponding to the maximum field angle of the optical lens. Meeting the above conditional formula, the optical lens has at least one or more advantages such as short focal length, large field angle, large entrance pupil diameter, short total length, large aperture, large format, low distortion, and low sensitivity.

[0055] In some embodiments, the lens material in the optical lens provided by the present invention can be glass or plastic. When the lens material is plastic, the production cost can be effectively reduced. On the other hand, when the lens material is glass, due to the low dispersion characteristic of glass itself, the geometric chromatic aberration of the optical system can be effectively corrected. The first lens and the fourth lens in the optical lens provided by the present invention can adopt glass materials, and the second lens, the third lens, the fifth lens, the sixth lens, the seventh lens, the eighth lens and the ninth lens can adopt plastic materials. Adopting a glass-plastic hybrid structure can effectively reduce costs, correct aberrations, reduce volume, improve thermal stability performance, and provide an optical lens product with higher cost performance.

[0056] In some embodiments, the first, second, third, fourth, fifth, sixth, seventh, eighth, and ninth lenses may be spherical or aspherical lenses. Compared to spherical lenses, aspherical structures can effectively reduce the aberrations of the optical system, thereby reducing the number and size of lenses and achieving better miniaturization. More specifically, the first and fourth lenses of the present invention are spherical lenses; the second, third, fifth, sixth, seventh, eighth, and ninth lenses are aspherical lenses.

[0057] In various embodiments of the present invention, when the lens is an aspheric lens, the shapes of the aspheric surfaces of the optical lens satisfy the following equations: ; Where z is the distance between the surface and the vertex 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, and B, C, D, E, F, G, H, I, and J are the fourth-order, sixth-order, eighth-order, tenth-order, twelfth-order, fourteenth-order, sixteenth-order, eighteenth-order, and twentieth-order surface coefficients, respectively.

[0058] 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.

[0059] Example 1 See also Figure 1 , shown is a schematic structural diagram of the optical lens 100 provided in Example 1 of the present invention. The optical lens 100 includes, in order from the object side to the imaging surface S21 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, a ninth lens L9 and a filter G1.

[0060] 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 positive refractive power, its object-side surface S3 is convex, and its image-side surface S4 is concave; The third lens L3 has positive refractive power, its object-side surface S5 is convex, 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 concave, and its image-side surface S16 is convex near the optical axis; The ninth lens L9 has positive refractive power, its object-side surface S17 is convex at the near optical axis, and its image-side surface S18 is concave at the near optical axis; The object-side surface S19 and the image-side surface S20 of the filter G1 are both flat surfaces; The imaging surface S21 is a plane.

[0061] 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, the eighth lens L8 and the ninth lens L9 are plastic aspherical lenses.

[0062] The relevant parameters of each lens in the optical lens 100 in Example 1 are shown in Table 1-1.

[0063] Table 1-1 The surface parameters of the aspheric lens of the optical lens 100 in Example 1 are shown in Table 1-2.

[0064] Table 1-2 In this embodiment, the F-Theta distortion curve, field curvature curve, and vertical axis chromatic aberration curve of the optical lens 100 are shown in FIG. Figure 2 、 Figure 3 、 Figure 4 shown.

[0065] Figure 2 The following figure shows the F-Theta distortion curve of the optical lens 100 in this embodiment, which represents the distortion at 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: °). As can be seen from the figure, the distortion value is controlled within ±10%, indicating that the optical lens 100 is able to correct distortion well.

[0066] Figure 3A field curvature graph of the optical lens 100 in this embodiment is shown, showing the field curvature of light in the meridional and sagittal image planes. The horizontal axis represents the offset (unit: mm), and the vertical axis represents the half field angle (unit: degrees). As can be seen from the graph, the field curvature in the meridional and sagittal image planes is controlled within ±0.1mm, indicating that the optical lens 100 can effectively correct field curvature.

[0067] Figure 4 A graph showing 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 both the longest and shortest wavelengths is controlled within a range of -1 μm to 5 μm, demonstrating that the optical lens 100 is capable of effectively correcting vertical chromatic aberration.

[0068] Example 2 See also Figure 5 , shown is a schematic structural diagram of an optical lens 200 provided in Example 2 of the present invention. Compared with Example 1, this embodiment mainly differs in that: the object-side surface S11 of the sixth lens L6 is a convex surface; the object-side surface S15 of the eighth lens L8 is a convex surface; and the image-side surface S16 of the eighth lens L8 is a concave surface; and the optical parameters such as the curvature radius of each lens surface and the lens thickness are different.

[0069] The relevant parameters of each lens in the optical lens 200 in Example 2 are shown in Table 2-1.

[0070] Table 2-1 The surface parameters of the aspheric lens of the optical lens 200 in Example 2 are shown in Table 2-2.

[0071] Table 2-2 In this embodiment, the F-Theta distortion curve, field curvature curve, and vertical axis chromatic aberration curve of the optical lens 200 are shown in FIG. Figure 6 、 Figure 7 、 Figure 8 shown.

[0072] from Figure 6 It can be seen that the distortion value is controlled within -10% to 0, indicating that the optical lens 200 can correct the distortion well.

[0073] from Figure 7 It can be seen from the figure that the field curvature of the meridional image plane and the sagittal image plane is controlled within ±0.05 mm, indicating that the optical lens 200 can correct the field curvature well.

[0074] from Figure 8 It can be seen from the figure that the vertical chromatic aberration of the longest wavelength and the shortest wavelength is controlled within 0~3μm, indicating that the optical lens 200 can better correct the vertical chromatic aberration.

[0075] Example 3 See also Figure 9 , shown is a schematic structural diagram of an optical lens 300 provided in Example 3 of the present invention. Compared with Example 1, this embodiment mainly differs in that: the object-side surface S11 of the sixth lens L6 is a convex surface; the object-side surface S15 of the eighth lens L8 is a convex surface; and the image-side surface S16 of the eighth lens L8 is a concave surface; and the optical parameters such as the curvature radius of each lens surface and the lens thickness are different.

[0076] The relevant parameters of each lens in the optical lens 300 in Example 3 are shown in Table 3-1.

[0077] Table 3-1 The surface parameters of the aspheric lens of the optical lens 300 in Example 3 are shown in Table 3-2.

[0078] Table 3-2 In this embodiment, the F-Theta distortion curve, field curvature curve, and vertical axis chromatic aberration curve of the optical lens 300 are shown in FIG. Figure 10 、 Figure 11 、 Figure 12 shown.

[0079] from Figure 10 It can be seen that the distortion value is controlled within -40% to 0, indicating that the optical lens 300 can correct the distortion well.

[0080] from Figure 11 It can be seen from the figure that the field curvature of the meridional image plane and the sagittal image plane is controlled within ±0.05 mm, indicating that the optical lens 300 can correct the field curvature well.

[0081] 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 -1μm~3μm, indicating that the optical lens 300 can better correct the vertical axis chromatic aberration.

[0082] Please refer to Table 4, 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.

[0083] Table 4 In summary of the above embodiments, the optical lens provided by the present invention uses nine lenses with specific optical powers. Through specific surface shape matching 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 of short focus, miniaturization, large field of view, large aperture, large target surface, low distortion, and low sensitivity.

[0084] Throughout this specification, reference to terms such as "one embodiment," "some embodiments," "examples," "specific examples," or "some examples" means that a specific feature, structure, material, or characteristic described in conjunction with that embodiment or example is 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.

[0085] 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 nine lenses, characterized in that: Along the optical axis from the object side to the imaging surface, it includes: The first lens has a negative optical power, its object-side surface is convex and its image-side surface is concave; a second lens having positive refractive power, whose object-side surface is convex and whose image-side surface is concave; a third lens element having positive optical power, whose object-side surface is convex and whose image-side surface is concave; a fourth lens element having positive refractive power, whose object-side surface is concave and whose image-side surface is convex; a fifth lens element having positive refractive power, whose object-side surface and image-side surface are convex; a sixth lens element having negative optical power and a concave image-side surface; a seventh lens element having positive refractive power, whose object-side surface and image-side surface are convex; an eighth lens having negative optical power; The ninth lens element has positive refractive power, its object-side surface is convex near the optical axis, and its image-side surface is concave near the optical axis; The total optical length TTL of the optical lens and the aperture value Fno of the optical lens satisfy: 7.5mm <TTL / Fno<9.1mm。 2. The optical lens according to claim 1, wherein: The total optical length TTL of the optical lens and the effective focal length f of the optical lens satisfy: 5.2 <TTL / f<8.2。 3. The optical lens according to claim 1, wherein: The focal length f2 of the second lens, the focal length f3 of the third lens, the focal length f4 of the fourth lens, the focal length f5 of the fifth lens and the effective focal length f of the optical lens satisfy: 19<(f2+f3+f4+f5) / f<42.

4. The optical lens according to claim 1, wherein: The total optical length TTL of the optical lens, the center thickness CT4 of the fourth lens, the center thickness CT5 of the fifth lens and the center thickness CT6 of the sixth lens meet the following requirements: 2.8 <TTL / (CT4+CT5+CT6)<5.4。 5. The optical lens according to claim 1, wherein: The half-aperture sag height SAG81 of the object side light of the eighth lens and the half-aperture sag height SAG82 of the image side light of the eighth lens meet the following conditions: -27 <SAG81 / SAG82<-9。 6. The optical lens according to claim 1, wherein: A curvature radius R1 of the object side surface of the first lens and a curvature radius R2 of the image side surface of the first lens satisfy: 0.6<(R1-R2) / (R1+R2)<0.

8.

7. The optical lens according to claim 1, wherein: The image side light semi-aperture CSD92 of the ninth lens and the image side light semi-aperture sag SAG92 of the ninth lens satisfy: -9.3 <CSD92 / SAG92<-3.5。 8. The optical lens according to claim 1, wherein: The focal length f1 of the first lens and the effective focal length f of the optical lens satisfy: -2.9 <f1 / f<-2。 9. The optical lens according to claim 1, wherein: The focal length f6 of the sixth lens and the effective focal length f of the optical lens satisfy: <f6 / f<-1.5。 10. The optical lens according to claim 1, wherein: The focal length f7 of the seventh lens and the effective focal length f of the optical lens satisfy: 1.6 <f7 / f<2.7。

Images