Optical lens

Abstract

The application provides an optical lens, which comprises, in sequence from an object side to an imaging surface along an optical axis, a first lens with negative focal power, wherein the object side of the first lens is a convex surface and the image side of the first lens is a concave surface; a second lens with negative focal power, wherein the object side of the second lens is a convex surface and the image side of the second lens is a concave surface; a third lens with negative focal power, wherein the object side of the third lens is a concave surface and the image side of the third lens is a concave surface; a fourth lens with positive focal power, wherein the object side of the fourth lens is a concave surface and the image side of the fourth lens is a convex surface; a fifth lens with positive focal power, wherein the object side of the fifth lens is a convex surface; a stop; a sixth lens with positive focal power, wherein the object side of the sixth lens is a convex surface; a seventh lens with negative focal power; an eighth lens with positive focal power, wherein the object side of the eighth lens is a convex surface; and a ninth lens with focal power, wherein the image side of the ninth lens is a concave surface; wherein the distance DL between the stop and the imaging surface on the optical axis and the total optical length TTL of the optical lens satisfy the condition: 0.18 < DL / TTL < 0.25. The optical lens provided by the application has the advantages of a large field of view and high imaging quality.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of imaging lens, in particular to an optical lens. BACKGROUND

[0002] With the wide application of electronic products such as mobile phones, tablets, drones and computers in life, the camera lens as an important component has become one of the focuses of people's attention. At the same time, whether the camera lens can shoot high-quality, high-resolution and high-definition images has become a key factor for people to choose electronic products.

[0003] However, the camera lens in the prior art has a small field of view and poor imaging clarity. Therefore, how to realize the wide-angle of the camera lens while considering the good imaging quality has become one of the technical problems that the industry wants to solve urgently. SUMMARY

[0004] In view of the above technical problems, the purpose of the present application is to provide an optical lens which at least has the advantages of large field of view and high imaging quality.

[0005] To achieve the above purpose, the present application provides an optical lens, which is sequentially arranged along the optical axis from the object side to the imaging surface: a first lens with negative focal power, the object side surface of which is convex, and the image side surface of which is concave; a second lens with negative focal power, the object side surface of which is convex, and the image side surface of which is concave; a third lens with negative focal power, the object side surface of which is concave, and the image side surface of which is concave; a fourth lens with positive focal power, the object side surface of which is concave, and the image side surface of which is convex; a fifth lens with positive focal power, the object side surface of which is convex; a stop; a sixth lens with positive focal power, the object side surface of which is convex; a seventh lens with negative focal power; an eighth lens with positive focal power, the object side surface of which is convex; a ninth lens with focal power, the image side surface of which is concave; wherein the distance DL of the stop to the imaging surface on the optical axis and the total optical length TTL of the optical lens satisfy: 0.18 < DL / TTL < 0.25.

[0006] Compared with the prior art, the present application has the following advantages: the optical lens provided by the present application adopts 9 lenses, and by reasonably allocating the focal power of each lens and reasonably setting the surface shape of each lens, as well as reasonably adjusting the thickness of each lens and the distance between each lens, the balance of large field of view and high imaging quality can be realized. BRIEF DESCRIPTION OF DRAWINGS

[0007] Figure 1 The structure diagram of the optical lens of the present application embodiment 1.

[0008] Figure 2 The optical distortion curve of the optical lens in the present application embodiment 1.

[0009] Figure 3 MTF curve of the optical lens in Embodiment 1 of the present application.

[0010] Figure 4 Curvature plot of the lateral chromatic aberration of the optical lens in Embodiment 1 of the present application.

[0011] Figure 5 Structure schematic diagram of the optical lens in Embodiment 2 of the present application.

[0012] Figure 6 Optical distortion curve of the optical lens in Embodiment 2 of the present application.

[0013] Figure 7 MTF curve of the optical lens in Embodiment 2 of the present application.

[0014] Figure 8 Curvature plot of the lateral chromatic aberration of the optical lens in Embodiment 2 of the present application.

[0015] Figure 9 Structure schematic diagram of the optical lens in Embodiment 3 of the present application.

[0016] Figure 10 Optical distortion curve of the optical lens in Embodiment 3 of the present application.

[0017] Figure 11 MTF curve of the optical lens in Embodiment 3 of the present application.

[0018] Figure 12 Curvature plot of the lateral chromatic aberration of the optical lens in Embodiment 3 of the present application. DETAILED DESCRIPTION

[0019] For a better understanding of the present application, various aspects of the present application will be described in more detail below with reference to the accompanying drawings. It is to be understood that the detailed description is merely descriptive of embodiments of the present application and is not intended to limit the scope of the present application in any way. Throughout the specification, like reference numerals refer to like elements. The expression “and / or” includes any and all combinations of one or more of the associated listed items.

[0020] It should be noted that the expressions first, second, third, etc. in the present specification are merely used to distinguish one feature from another feature, and do not represent any limitation on the features. Therefore, the first lens discussed below can also be referred to as the second lens or the third lens without departing from the teachings of the present application.

[0021] In the drawings, the thickness, size, and shape of the lenses have been exaggerated slightly for ease of explanation. Specifically, the shape of the spherical or aspherical surface shown in the drawings is shown by way of example. That is, the shape of the spherical or aspherical surface is not limited to the shape of the spherical or aspherical surface shown in the drawings. The drawings are merely examples and are not drawn to scale.

[0022] In this document, the paraxial region refers to a region near the optical axis. If a lens surface is convex and the position of the convex surface is not specified, it means that the lens surface is convex at least in the paraxial region. If a lens surface is concave and the position of the concave surface is not specified, it means that the lens surface is concave at least in the paraxial region. The surface of each lens closest to the object is referred to as the object side surface of the lens, and the surface of each lens closest to the image plane is referred to as the image side surface of the lens.

[0023] It should also be understood that the use of the terms "including", "including have", "have", "contain" and / or "contain have", when used in this specification, indicates the presence of the stated features, elements and / or components, but does 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 list of features and not the individual elements of the list. In addition, when describing embodiments of the present application, the use of "may" indicates "one or more embodiments of the present application". And the term "exemplary" is intended to refer to an example or illustration.

[0024] Unless otherwise defined, all terms used in this document, including technical terms and scientific terms, have the same meaning as commonly understood by those skilled in the art to which the present application belongs. It should also be understood that terms (such as terms defined in common dictionaries) should be interpreted in accordance with their meanings in the context of the relevant technology, and will not be interpreted in an idealized or overly formal sense, unless otherwise defined herein.

[0025] It should be noted that the embodiments in the present application and the features in the embodiments can be combined with each other without conflict. The present application will be described in detail below with reference to the drawings and in conjunction with embodiments.

[0026] The optical lens according to an embodiment of the present application comprises: a first lens, a second lens, a third lens, a fourth lens, a fifth lens, a diaphragm, a sixth lens, a seventh lens, an eighth lens, a ninth lens and a filter.

[0027] The first lens has negative focal power, the object side surface is a convex surface, and the image side surface is a concave surface; the second lens has negative focal power, the object side surface is a convex surface, and the image side surface is a concave surface; the third lens has negative focal power, the object side surface is a concave surface, and the image side surface is a concave surface; the fourth lens has positive focal power, the object side surface is a concave surface, and the image side surface is a convex surface; the fifth lens has positive focal power, the object side surface is a convex surface, and the image side surface is a convex surface; the sixth lens has positive focal power, the object side surface is a convex surface, and the image side surface is a convex surface; the seventh lens has negative focal power, the object side surface is a concave surface, and the image side surface is a concave surface; the eighth lens has positive focal power, the object side surface is a convex surface, and the image side surface is a convex surface; and the ninth lens has positive focal power or negative focal power, the object side surface is a convex surface, and the image side surface is a concave surface.

[0028] In some embodiments, a diaphragm can be arranged between the fifth lens and the sixth lens to condense the range of light rays exiting the front end of the optical lens and reduce the aperture of the rear end of the optical lens.

[0029] In some embodiments, the sixth lens and the seventh lens can be cemented to form a cemented lens to share chromatic aberration correction of the optical lens, improve the resolution of the optical lens, and make the structure of the optical lens compact, which is conducive to the miniaturization of the optical lens.

[0030] In some embodiments, the maximum field of view FOV of the optical lens satisfies 220°<FOV. Satisfying the above range is conducive to realizing the ultra-wide-angle characteristic, so that more scene information can be obtained, and the demand for large-range detection can be met.

[0031] In some embodiments, the distance DL of the diaphragm to the imaging surface on the optical axis and the total optical length TTL of the optical lens satisfy 0.18<DL / TTL<0.25. Satisfying the above range can reasonably adjust the ratio of the front lens group and the rear lens group of the diaphragm to the total optical length, which is conducive to making the front lens group of the diaphragm better to incident light rays in a large angle range to the rear lens group of the diaphragm, improving the light flux while realizing the balance of the large field of view and the high imaging quality. More preferably, the distance DL of the diaphragm to the imaging surface on the optical axis and the total optical length TTL of the optical lens satisfy 0.20<DL / TTL<0.23.

[0032] In some embodiments, the total optical length TTL of the optical lens and the effective focal length f satisfy 20<TTL / f<24. Satisfying the above range can effectively limit the length and volume of the optical lens, and realize the miniaturization of the optical lens.

[0033] In some embodiments, the effective focal length f of the optical lens and the image height IH corresponding to the maximum field of view satisfy 0.2<f / IH<0.3. Satisfying the above range can realize the wide-angle characteristic to meet the demand for large-range shooting, and also can realize the large image surface characteristic to improve the imaging quality of the optical lens.

[0034] In some embodiments, the maximum field of view FOV of the optical lens and the F-number FNO satisfy: 110 < FOV / FNO. Satisfying the above range is conducive to expanding the field of view of the optical lens and increasing the aperture of the optical lens, achieving the characteristics of wide angle and large aperture.

[0035] In some embodiments, the effective focal length f1 of the first lens and the effective focal length f of the optical lens satisfy: -15.0 < f1 / f < -12.0. Satisfying the above range is conducive to making the refraction angle of the incident light change more gently, avoiding the refraction angle changing too strongly to produce too much aberration, and at the same time helping more light to enter the rear optical system, increasing the illumination, and improving the imaging quality of the optical lens.

[0036] In some embodiments, the combined focal length f123 of the first lens, the second lens and the third lens and the combined focal length f45 of the fourth lens and the fifth lens satisfy: -13.0 < f123 / f45 < -11.0; the combined focal length f45 of the fourth lens and the fifth lens and the effective focal length f of the optical lens satisfy: 5.0 < f45 / f < 8.0. Satisfying the above range can reasonably distribute the refractive power of the front lens group of the stop, which is conducive to making the light smooth and reducing the correction difficulty of aberration, thereby improving the imaging quality of the optical lens.

[0037] In some embodiments, the effective focal length f6 of the sixth lens and the effective focal length f7 of the seventh lens satisfy: -1.8 < f6 / f7 < -1.0. Satisfying the above range can reasonably adjust the refractive power of the sixth lens and the seventh lens, which is conducive to eliminating the chromatic aberration of the optical lens, reducing the correction difficulty of aberration, field curvature, distortion and the like, and improving the imaging quality of the optical lens.

[0038] In some embodiments, the combined focal length f67 of the sixth lens and the seventh lens and the combined focal length f89 of the eighth lens and the ninth lens satisfy: -85.0 < f67 / f89 < -25.0; the combined focal length f89 of the eighth lens and the ninth lens and the effective focal length f of the optical lens satisfy: 4.0 < f89 / f < 7.0. Satisfying the above range can reasonably distribute the refractive power of the rear lens group of the stop, improve the brightness of the imaging surface, correct various aberrations of the optical lens, and improve the imaging quality of the optical lens.

[0039] In some embodiments, the effective focal length f1 of the first lens and the effective focal length f8 of the eighth lens satisfy: -5.0 < f1 / f8 < -2.0. Satisfying the above range can reasonably control the turning trend of the incident light at the edge field of view, reduce the correction difficulty of field curvature, aberration, distortion and the like, and improve the imaging quality of the optical lens.

[0040] In some embodiments, the optical back focal length BFL of the optical lens and the effective focal length f satisfy: 1.3 < BFL / f < 1.6. Satisfying the above range, the optical lens has a longer optical back focal length, which is beneficial to the assembly of the optical lens.

[0041] In some embodiments, the effective focal length f2 of the second lens and the effective focal length f of the optical lens satisfy: -7.0 < f2 / f < -5.0. Satisfying the above range, the light rays are smoothly transitioned, and the aberration caused by the excessive deflection of the light rays through the first lens is corrected, thereby improving the imaging quality of the optical lens.

[0042] In some embodiments, the effective focal length f3 of the third lens and the effective focal length f of the optical lens satisfy: -6.0 < f3 / f < -4.0; and the effective focal length f5 of the fifth lens and the effective focal length f of the optical lens satisfy: 4.0 < f5 / f < 7.0. Satisfying the above range, the central field of view and the edge field of view light rays are converged, which is beneficial to the condensation of the light rays, the compression of the total length of the optical lens, and the correction of the aberration of the optical lens, thereby improving the imaging quality of the optical lens.

[0043] In order to make the system have better optical performance, a plurality of aspherical lenses are used in the lens, and the shape of each aspherical surface of the optical lens satisfies the following equation:

[0044]

[0045] wherein z is the distance of the curved surface from the vertex of the curved surface in the direction of the optical axis, 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 quadratic surface coefficient, and A, B, C, D, E, and F are the second-order, fourth-order, sixth-order, eighth-order, tenth-order, and twelfth-order curved surface coefficients, respectively.

[0046] The application will be further described in the following embodiments. In each embodiment, the thickness, the radius of curvature, and the material selection of each lens in the optical lens are different, and the specific differences can be referred to the parameter table of each embodiment. The following embodiments are only the preferred embodiments of the application, but the embodiments of the application are not limited to the following embodiments only, and any changes, substitutions, combinations, or simplifications made without departing from the innovative points of the application should be regarded as equivalent replacement modes, and are included in the protection scope of the application.

[0047] Embodiment 1

[0048] Please refer to Figure 1Fig. 1 shows a structural schematic diagram of an optical lens 100 provided in Embodiment 1 of the present application, which comprises, along the optical axis from the object side to the imaging surface S20, a first lens L1, a second lens L2, a third lens L3, a fourth lens L4, a fifth lens L5, a diaphragm ST, a sixth lens L6, a seventh lens L7, an eighth lens L8, a ninth lens L9 and a filter G1.

[0049] The first lens L1 has negative focal power, the object side S1 is a convex surface, and the image side S2 is a concave surface; the second lens L2 has negative focal power, the object side S3 is a convex surface, and the image side S4 is a concave surface; the third lens L3 has negative focal power, the object side S5 is a concave surface, and the image side S6 is a concave surface; the fourth lens L4 has positive focal power, the object side S7 is a concave surface, and the image side S8 is a convex surface; the fifth lens L5 has positive focal power, the object side S9 is a convex surface, and the image side S10 is a convex surface; the sixth lens L6 has positive focal power, the object side S11 is a convex surface, and the image side is a convex surface; the seventh lens L7 has negative focal power, the object side is a concave surface, and the image side S13 is a concave surface, and the sixth lens L6 and the seventh lens L7 are cemented to form a cemented lens, and the cemented surface is S12; the eighth lens L8 has positive focal power, the object side S14 is a convex surface, and the image side S15 is a convex surface; the ninth lens L9 has positive focal power, the object side S16 is a convex surface, and the image side S17 is a concave surface; the filter G1 has a flat object side S18 and a flat image side S19.

[0050] The related parameters of the lenses in the optical lens in Embodiment 1 are shown in Table 1-1.

[0051] Table 1-1

[0052]

[0053] The curve coefficients of the aspheric lenses of the optical lens in Embodiment 1 are shown in Table 1-2.

[0054] Table 1-2

[0055]

[0056]

[0057] Figure 2 The optical distortion curve of Embodiment 1 is shown, which represents the distortion at different fields of view on the imaging surface, the horizontal axis represents percentage, and the vertical axis represents half field of view (unit: °). As can be seen from the figure, the optical distortion of the present embodiment is controlled within ±5%, which indicates that the distortion of the optical lens is well corrected.

[0058] Figure 3A modulation transfer function (MTF) curve of the optical lens of Embodiment 1 is shown, which represents the imaging modulation degree of different spatial frequencies under each field 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 the present embodiment is above 0.6 in the full field of view, and has good imaging quality and good detail resolution capability in both low and high frequency cases.

[0059] Figure 4 A curve of the optical lens of Embodiment 1 is shown, which represents the chromatic aberration of different image heights on the imaging surface with respect to the central wavelength (0.55 μm) at each wavelength, the horizontal axis represents the chromatic aberration value of each wavelength relative to the central wavelength (unit: μm), and the vertical axis represents the normalized field angle. As can be seen from the figure, the chromatic aberration of the longest wavelength and the shortest wavelength is controlled within ±1.5 μm, which indicates that the optical lens can very well correct the chromatic aberration of the edge field of view and the secondary spectrum of the entire image surface.

[0060] Embodiment 2

[0061] Please refer to Figure 5 , which is a structural schematic diagram of the optical lens 200 provided in Embodiment 2 of the present application. The optical lens in the present embodiment has substantially the same structure and shape as the optical lens in Embodiment 1, and the main difference is that the ninth lens has a negative focal power, and the curvature radius, central thickness, edge thickness and material of each lens are changed.

[0062] The related parameters of each lens in the optical lens of Embodiment 2 are shown in Table 2-1.

[0063] Table 2-1

[0064]

[0065]

[0066] The curve coefficients of the aspherical lenses of the optical lens of Embodiment 2 are shown in Table 2-2.

[0067] Table 2-2

[0068]

[0069] Figure 6 to Figure 8The distortion curve, the modulation transfer function (MTF) curve and the axial chromatic aberration curve of the optical lens of embodiment 2 are shown in the figures respectively. As can be seen from the figures, the optical distortion is controlled within 4%, which indicates that the distortion of the optical lens is well corrected; the MTF value of the optical lens is above 0.72 in the full field of view, and the optical lens has good imaging quality and good detail resolution ability in both low frequency and high frequency cases; the axial chromatic aberration of the longest wavelength and the shortest wavelength is controlled within ±1 μm, which indicates that the optical lens can well correct the chromatic aberration of the edge field and the secondary spectrum of the whole image plane.

[0070] Embodiment 3

[0071] Please refer to Figure 9 , which is a structural schematic diagram of the optical lens 300 provided in embodiment 3 of the present application. The optical lens in the present embodiment has substantially the same structure and shape as the optical lens in embodiment 1, and the main difference lies in that the ninth lens has a negative focal power, and the curvature radius, the center thickness, the edge thickness and the material of each lens are changed.

[0072] The related parameters of each lens in the optical lens in embodiment 3 are shown in Table 3-1.

[0073] Table 3-1

[0074]

[0075]

[0076] The surface coefficients of the aspherical lenses of the optical lens in embodiment 3 are shown in Table 3-2.

[0077] Table 3-2

[0078]

[0079] Figure 10 to Figure 12 The distortion curve, the modulation transfer function (MTF) curve and the axial chromatic aberration curve of the optical lens of embodiment 3 are shown in the figures respectively. As can be seen from the figures, the optical distortion is controlled within 3%, which indicates that the distortion of the optical lens is well corrected; the MTF value of the optical lens is above 0.67 in the full field of view, and the optical lens has good imaging quality and good detail resolution ability in both low frequency and high frequency cases; the axial chromatic aberration of the longest wavelength and the shortest wavelength is controlled within ±2 μm, which indicates that the optical lens can well correct the chromatic aberration of the edge field and the secondary spectrum of the whole image plane.

[0080] Please refer to Table 4, which is the optical properties corresponding to each of the above embodiments, including the effective focal length f, the maximum field of view FOV, the total optical length TTL, the aperture value FNO, the real image height IH of the optical lens, and the numerical value corresponding to each conditional expression in the embodiment.

[0081] Table 4

[0082]

[0083]

[0084] In the description of the present specification, the description of the terms "one embodiment", "some embodiments", "an example", "a specific example", or "some examples" and the like means that the specific features, structures, materials or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present application. In the present specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Also, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner.

[0085] The above-described embodiments only express several implementation manners of the present application, which are described in a more specific and detailed manner, but cannot be understood as a limitation on the patent scope of the present application. It should be noted that, for those skilled in the art, several modifications and improvements can be made without departing from the concept of the present application, which are all within the protection scope of the present application. Therefore, the patent protection scope of the present application should be subject to the appended claims.

Claims

1. An optical lens, comprising nine pieces of lenses, characterized in that, In order from the object side to the imaging plane along the optical axis are: a first lens with negative refractive power, an object side surface of the first lens being convex, an image side surface of the first lens being concave; a second lens with negative refractive power, an object side surface of the second lens being convex, an image side surface of the second lens being concave; a third lens with negative refractive power, an object side surface of the third lens being concave, an image side surface of the third lens being concave; a fourth lens with positive refractive power, an object side surface of the fourth lens being concave, an image side surface of the fourth lens being convex; a fifth lens with positive refractive power, an object side surface of the fifth lens being convex; a stop; a sixth lens with positive refractive power, an object side surface of the sixth lens being convex; a seventh lens with negative refractive power; an eighth lens with positive refractive power, an object side surface of the eighth lens being convex; a ninth lens with refractive power, an image side surface of the ninth lens being concave; wherein a distance DL on the optical axis from the stop to the imaging plane and a total track length TTL of the optical lens satisfy: 0.18 < DL / TTL < 0.25; a combined focal length f123 of the first lens, the second lens and the third lens and a combined focal length f45 of the fourth lens and the fifth lens satisfy: -13.0 < f123 / f45 < -11.

0.

2. The optical lens of claim 1, wherein, a total track length TTL of the optical lens and an effective focal length f of the optical lens satisfy: 20 < TTL / f < 24.

3. The optical lens of claim 1, wherein, an effective focal length f of the optical lens and an image height IH corresponding to a maximum field angle of the optical lens satisfy: 0.2 < f / IH < 0.

3.

4. The optical lens of claim 1, wherein, a maximum field angle FOV of the optical lens and an F-number FNO of the optical lens satisfy: 110° < FOV / FNO ≤ 120°.

5. The optical lens of claim 1, wherein, an effective focal length f1 of the first lens and an effective focal length f of the optical lens satisfy: -15.0 < f1 / f < -12.

0.

6. The optical lens of claim 1, wherein, a distance DL on the optical axis from the stop to the imaging plane and a total track length TTL of the optical lens satisfy: 0.215 ≤ DL / TTL ≤ 0.216; a combined focal length f123 of the first lens, the second lens and the third lens and a combined focal length f45 of the fourth lens and the fifth lens satisfy: -12.656 ≤ f123 / f45 ≤ -11.

519.

7. The optical lens of claim 1, wherein, an effective focal length f6 of the sixth lens and an effective focal length f7 of the seventh lens satisfy: -1.8 < f6 / f7 < -1.

0.

8. The optical lens of claim 1, wherein, a combined focal length f89 of the eighth lens and the ninth lens and an effective focal length f of the optical lens satisfy: 4.0 < f89 / f < 7.

0.

9. The optical lens of claim 1, wherein, an effective focal length f1 of the first lens and an effective focal length f8 of the eighth lens satisfy: -5.0 < f1 / f8 < -2.

0.

10. The optical lens of claim 1, wherein, an optical back focal length BFL of the optical lens and an effective focal length f of the optical lens satisfy: 1.3 < BFL / f < 1.6.

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