Optical lens

Abstract

The application discloses an optical lens, which comprises, along the optical axis, from the object plane to the imaging plane, a first lens with negative focal length, the object side of which is concave near the optical axis, and the image side is concave; a diaphragm; a second lens with positive focal length, the object side of which is convex, and the image side is convex; a third lens with negative focal length, the image side of which is concave; a fourth lens with positive focal length, the object side of which is concave near the optical axis, and the image side is convex; a fifth lens with positive focal length; a sixth lens with negative focal length, the image side of which is concave near the optical axis; and a filter without focal length. The optical lens of the application adopts six aspheric lenses with focal length and one filter without focal length, and has the advantages of large field of view, short total length and high resolution.

Description

TECHNICAL FIELD

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

[0002] In recent years, with the rapid development of science and technology, consumers have increasingly high requirements for the imaging quality of mobile electronic products such as smart phones, and most of the rear cameras of mobile phones are equipped with at least two lenses, one main camera lens and one wide-angle lens. However, the existing wide-angle lens generally adopts a structure of four to five lenses, which cannot meet the requirements of large field of view and short total length at the same time, and therefore it is necessary to design an optical wide-angle lens with large field of view, short total length and good imaging quality. SUMMARY

[0003] Therefore, the present application aims to provide an optical lens with at least the advantages of large field of view, short total length and high imaging quality.

[0004] The present application provides an optical lens, which comprises, in order from the object side to the imaging surface along the optical axis: a first lens with negative focal power, the object side surface of which is concave near the optical axis and the image side surface of which is concave; a stop; a second lens with positive focal power, the object side surface of which is convex and the image side surface of which is convex; a third lens with negative focal power, the image side surface of which is concave; a fourth lens with positive focal power, the object side surface of which is concave near the optical axis and the image side surface of which is convex; a fifth lens with positive focal power; a sixth lens with negative focal power, the image side surface of which is concave near the optical axis; and a filter without focal power.

[0005] Compared with the prior art, the optical lens provided by the present application has the characteristics of large field of view, short total length and high imaging quality by reasonably allocating the thickness and focal power of the six lenses and reasonably controlling the surface shape of each lens. BRIEF DESCRIPTION OF DRAWINGS

[0006] Figure 1 The structure schematic diagram of the optical lens provided by the first embodiment of the present application is shown in the figure;

[0007] Figure 2 The vertical axis chromatic aberration curve of the optical lens in the first embodiment of the present application is shown in the figure;

[0008] Figure 3 The optical distortion curve of the optical lens in the first embodiment of the present application is shown in the figure;

[0009] Figure 4 The axial aberration curve of the optical lens in the first embodiment of the present application is shown in the figure;

[0010] Figure 5 The structure schematic diagram of the optical lens provided by the second embodiment of the present application is shown in the figure;

[0011] Figure 6 A curve graph of the optical lens in the second embodiment of the present application is shown in FIG. 6.

[0012] Figure 7 A curve graph of the optical lens in the second embodiment of the present application is shown in FIG. 6.

[0013] Figure 8 A curve graph of the optical lens in the second embodiment of the present application is shown in FIG. 6.

[0014] Figure 9 A curve graph of the optical lens in the second embodiment of the present application is shown in FIG. 6.

[0015] Figure 10 A curve graph of the optical lens in the second embodiment of the present application is shown in FIG. 6.

[0016] Figure 11 A curve graph of the optical lens in the second embodiment of the present application is shown in FIG. 6.

[0017] Figure 12 A curve graph of the optical lens in the second embodiment of the present application is shown in FIG. 6.

[0018] Figure 13 A curve graph of the optical lens in the second embodiment of the present application is shown in FIG. 6.

[0019] Figure 14 A curve graph of the optical lens in the second embodiment of the present application is shown in FIG. 6.

[0020] Figure 15 A curve graph of the optical lens in the second embodiment of the present application is shown in FIG. 6.

[0021] Figure 16 A curve graph of the optical lens in the second embodiment of the present application is shown in FIG. 6. DETAILED DESCRIPTION

[0022] In order to facilitate the understanding of the present application, the present application will be described more fully below in connection with the accompanying drawings. The drawings show several embodiments of the present application. However, the present application can be embodied in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided so that the disclosure of the present application will be more thorough and complete.

[0023] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used in the description of the application herein is for describing particular embodiments only and is not intended to be limiting of the application. As used in the description of the application and the appended claims, the singular forms "a", "an", and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise.

[0024] The optical lens comprises, in sequence from an object side to an image plane along an optical axis, a first lens, a diaphragm, a second lens, a third lens, a fourth lens, a fifth lens, a sixth lens, and a filter.

[0025] The first lens has negative optical power, the object side surface of the first lens is concave near the optical axis, and the image side surface of the first lens is concave; the second lens has positive optical power, the object side surface of the second lens is convex, and the image side surface of the second lens is convex; the third lens has negative optical power, and the image side surface of the third lens is concave; the fourth lens has positive optical power, the object side surface of the fourth lens is concave near the optical axis, and the image side surface of the fourth lens is convex; the fifth lens has positive optical power; the sixth lens has negative optical power, and the image side surface of the sixth lens is concave near the optical axis; and the first lens to the sixth lens are all aspherical lenses.

[0026] In some embodiments, the optical lens satisfies the following conditional expression:

[0027] 2 < f5 / f < 6; (1)

[0028] f5 represents the focal length of the fifth lens, and f represents the effective focal length of the optical lens. By reasonably allocating the relationship between the focal length of the fifth lens and the effective focal length of the optical lens, the conditional expression (1) is satisfied, which is conducive to correcting the spherical aberration of the optical lens in the axial field of view and improving the imaging quality of the optical lens.

[0029] In some embodiments, the optical lens satisfies the following conditional expression:

[0030] 1.7 < R41 / R42 < 2.9; (2)

[0031] R41 represents the curvature radius of the object side surface of the fourth lens, and R42 represents the curvature radius of the image side surface of the fourth lens. By reasonably controlling the surface shape of the fourth lens, the conditional expression (2) is satisfied, which is conducive to obtaining a larger image height, correcting the aberration of the off-axis field of view, and improving the imaging quality of the optical system.

[0032] In some embodiments, the optical lens satisfies the following conditional expression:

[0033] -1.5 < R21 / R22 < -0.9; (3)

[0034] 1.7 < CT2 / CT1 < 2.5; (4)

[0035] Wherein, R21 represents the curvature radius of the object side surface of the second lens, R22 represents the curvature radius of the image side surface of the second lens, CT2 represents the center thickness of the second lens, and CT1 represents the center thickness of the first lens. The above conditional expressions (3) and (4) are met, the face type of the second lens and the center thicknesses of the second lens and the first lens are reasonably controlled, the angle between the chief ray of the outer field of view and the optical axis is reduced, the large field of view light is clearly imaged on the image plane, and the field of view angle of the optical lens is increased.

[0036] In some embodiments, the optical lens meets the following conditional expression:

[0037] 0.3 < f4 / f < 0.5; (5)

[0038] Wherein, f4 represents the focal length of the fourth lens, and f represents the effective focal length of the optical lens. The above conditional expression (5) is met, the focal length of the fourth lens is reasonably controlled, the field curvature of the optical lens is corrected, and the imaging quality of the optical lens is improved.

[0039] In some embodiments, the optical lens meets the following conditional expression:

[0040] 0.8 < CT4 / CT5 < 1.1; (6)

[0041] -0.45 < SAG51 / CT5 < -0.25; (7)

[0042] Wherein, CT4 represents the center thickness of the fourth lens, CT5 represents the center thickness of the fifth lens, and SAG51 represents the sag of the object side surface of the fifth lens. The above conditional expressions (6) and (7) are met at the same time, the center thicknesses and the sag of the fourth lens and the fifth lens are reasonably controlled, the coma of the optical lens in the off-axis field of view is corrected, and the imaging quality of the optical lens is improved.

[0043] In some embodiments, the optical lens meets the following conditional expression:

[0044] -0.2 < R62 / R61 < 0.1; (8)

[0045] Wherein, R62 represents the curvature radius of the image side surface of the sixth lens, and R61 represents the curvature radius of the object side surface of the sixth lens. The above conditional expression (8) is met, the face type of the sixth lens is reasonably controlled, the aberrations of different fields of view are corrected respectively, and the imaging quality of the optical lens is improved.

[0046] In some embodiments, the optical lens meets the following conditional expression:

[0047] 0.06 < (CT23 + CT34 + CT45 + CT56) / TTL < 0.08; (9)

[0048] wherein CT23 represents an air gap of the second lens and the third lens on the optical axis, CT34 represents an air gap of the third lens and the fourth lens on the optical axis, CT45 represents an air gap of the fourth lens and the fifth lens on the optical axis, CT56 represents an air gap of the fifth lens and the sixth lens on the optical axis, and TTL represents a distance from a lens object side of the first lens to an imaging plane on the optical axis. The condition formula (9) is satisfied, and by reasonably controlling the proportion of the sum of the air gaps of the second lens to the sixth lens in the total optical length, the distribution of the second lens, the third lens, the fourth lens, the fifth lens and the sixth lens is more compact, the total length of the optical lens is reduced, and the miniaturization of the optical lens is facilitated.

[0049] In some embodiments, the optical lens satisfies the following condition formula:

[0050] -0.5 < (φ32 - φ31) / (φ42 - φ41) < -0.1; (10)

[0051] wherein φ32 represents a refractive power of an image side surface of the third lens, φ31 represents a refractive power of a lens object side surface of the third lens, φ42 represents a refractive power of an image side surface of the fourth lens, and φ41 represents a refractive power of a lens object side surface of the fourth lens. The condition formula (10) is satisfied, and by reasonably controlling the refractive powers of the third lens and the fourth lens, the high-order aberration of the optical lens is corrected, and the imaging quality of the optical lens is improved.

[0052] In some embodiments, the optical lens satisfies the following condition formula:

[0053] 0.21 < FFL / TTL < 0.25; (11)

[0054] wherein FFL represents a distance from an image side surface of the sixth lens to an imaging plane on the optical axis, and TTL represents a distance from a lens object side surface of the first lens to an imaging plane on the optical axis. The condition formula (11) is satisfied, and by reasonably controlling the relationship between the optical back focal length and the total optical length of the optical lens, the risk of interference between the mechanism and the lens is reduced, and the mechanism design of the product is facilitated.

[0055] In some embodiments, the optical lens satisfies the following condition formula:

[0056] -3.5 < (φ61 + φ62) / (φ51 + φ52) < -1.0; (12)

[0057] Wherein, φ61 represents the power of the object side of the sixth lens, φ62 represents the power of the image side of the sixth lens, φ51 represents the power of the object side of the fifth lens, and φ52 represents the power of the image side of the fifth lens. The above condition (12) is met, and by reasonably controlling the powers of the fifth lens and the sixth lens, the spherical aberration of each field of view of the optical lens is corrected, and the imaging quality of the optical lens is improved.

[0058] In some embodiments, the optical lens meets the following condition:

[0059] -0.75 < (f2xf3) / (f4xf5) < -0.25; (13)

[0060] Wherein, f2 represents the focal length of the second lens, f3 represents the focal length of the third lens, f4 represents the focal length of the fourth lens, and f5 represents the focal length of the fifth lens. The above condition (13) is met, and by reasonably controlling the focal lengths of the second lens, the third lens, the fourth lens and the fifth lens, the spherical aberration of the central field of view of the optical lens is corrected, the imaging quality of the optical lens is improved, the effective focal length of the optical lens is controlled, and the field of view angle of the optical lens is increased.

[0061] In some embodiments, the optical lens meets the following condition:

[0062] -2.0 < SAG31 / SAG32 < -0.7; (14)

[0063] 0.5 < (SAG32-SAG31) / CT3 < 0.7; (15)

[0064] Wherein, SAG31 represents the sag of the object side of the third lens, SAG32 represents the sag of the image side of the third lens, and CT3 represents the center thickness of the third lens. The above conditions (14) and (15) are met, and by reasonably controlling the surface shape of the third lens and the relationship with the center thickness of the third lens, the light rays smoothly pass through the third lens, the aberration of the optical lens is corrected, and the imaging quality of the optical lens is improved.

[0065] In some embodiments, the optical lens meets the following condition:

[0066] -0.45 < SAG41 / SAG42 < -0.25; (16)

[0067] Wherein, SAG41 represents the sag of the object side of the fourth lens, and SAG42 represents the sag of the image side of the fourth lens. The above condition (16) is met, and by reasonably controlling the sag of the fourth lens, the aberration of different fields of view is corrected respectively, and the imaging quality of the optical lens is improved.

[0068] In some embodiments, the optical lens satisfies the following conditional expression:

[0069] -5 < SAG51 / CT45 < -2; (17)

[0070] wherein SAG51 represents the sag of the fifth lens on the object side, and CT45 represents the air separation of the fourth lens and the fifth lens on the optical axis. By satisfying the above conditional expression (17), the distribution of the fourth lens and the fifth lens is made more compact, and the total length of the optical lens is reduced, thereby achieving miniaturization of the optical lens, by reasonably controlling the relationship between the sag of the fifth lens on the object side and the air separation of the fourth lens and the fifth lens.

[0071] In some embodiments, the optical lens satisfies the following conditional expression:

[0072] -18 < SAG61 / CT56 < -6; (18)

[0073] 3 < (SAG62-SAG61) / CT56 < 11; (19)

[0074] wherein SAG61 represents the sag of the sixth lens on the object side, SAG62 represents the sag of the sixth lens on the image side, and CT56 represents the air separation of the fifth lens and the sixth lens on the optical axis. By satisfying the above conditional expressions (18) and (19), the distribution of the fifth lens and the sixth lens is made more compact, and the total length of the optical lens is reduced, thereby achieving miniaturization of the optical lens, by reasonably controlling the air separation of the fifth lens and the sixth lens and the sag of the sixth lens.

[0075] In various embodiments of the present application, when the lens is a non-spherical lens, the surface shape of the non-spherical lens satisfies the following equation:

[0076]

[0077] wherein z is the sag of the non-spherical surface at a position of height h along the optical axis, c is the paraxial curvature of the surface, k is the conic coefficient, A 2i is the non-spherical surface type coefficient of the 2i-th order.

[0078] The application will be further described in the following embodiments. In each embodiment, the thickness, the radius of curvature, 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, any changes, substitutions, combinations or simplifications made without departing from the innovative points of the application should be regarded as equivalent replacement, and are included in the protection scope of the application.

[0079] First embodiment

[0080] Please refer to Figure 1 , which is a structural schematic diagram of an optical lens 100 provided in the first embodiment of the application. The optical lens 100 includes, in order from the object side to the imaging surface S15 along the optical axis, a first lens L1, a stop ST, a second lens L2, a third lens L3, a fourth lens L4, a fifth lens L5, a sixth lens L6 and a filter G1.

[0081] Specifically, the first lens L1 has a negative focal power, the object side surface S1 of the first lens is concave at the near optical axis, and the image side surface S2 of the first lens is concave; the second lens L2 has a positive focal power, the object side surface S3 of the second lens is convex, and the image side surface S4 of the second lens is convex; the third lens L3 has a negative focal power, the object side surface S5 of the third lens is convex at the near optical axis, and the image side surface S6 of the third lens is concave; the fourth lens L4 has a positive focal power, the object side surface S7 of the fourth lens is concave at the near optical axis, and the image side surface S8 of the fourth lens is convex; the fifth lens L5 has a positive focal power, the object side surface S9 of the fifth lens is concave, and the image side surface S10 of the fifth lens is convex; the sixth lens L6 has a negative focal power, the object side surface S11 of the sixth lens is concave, and the image side surface S12 of the sixth lens is concave at the near optical axis; the object side surface of the filter G1 is S13, and the image side surface is S14. Among them, the first lens L1 to the sixth lens L6 are plastic aspheric lenses.

[0082] The related parameters of each lens in the optical lens 100 provided in the first embodiment of the application are shown in Table 1.

[0083] Table 1

[0084]

[0085]

[0086] The surface type coefficients of each aspheric surface of the optical lens 100 in the embodiment are shown in Table 2.

[0087] Table 2

[0088]

[0089]

[0090] In the embodiment, the structural diagram, the curve diagram of the axial chromatic aberration, the curve diagram of the optical distortion and the curve diagram of the axial aberration of the optical lens 100 are shown in Figure 1 、 Figure 2 、 Figure 3 and Figure 4 respectively.

[0091] Figure 2 The curve diagram of the axial chromatic aberration of the optical lens 100 in the embodiment is shown, which represents the axial chromatic aberration values at different fields of view, and it can be seen from the diagram that the axial chromatic aberration values at different fields of view are controlled within ±2μm, which indicates that the axial chromatic aberration of the optical lens 100 at different fields of view is well corrected.

[0092] Figure 3 The curve diagram of the optical distortion of the optical lens 100 in the embodiment is shown, which represents the distortion at different fields of view on the imaging plane, and it can be seen from the diagram that the optical distortion is controlled within ±25%, and the optical distortion of the field of view of 0-48° is controlled within ±5%, which indicates that the distortion of the optical lens 100 is well corrected.

[0093] Figure 4 The curve diagram of the axial aberration of the optical lens 100 in the embodiment is shown, which represents the axial aberration of different wavelengths in the optical axis direction on the optical axis, and it can be seen from the diagram that the axial aberration of all wavelengths is controlled within ±0.03mm, which indicates that the axial aberration of the optical lens 100 is well corrected.

[0094] Second Embodiment

[0095] Please refer to Figure 5 , which is a structural schematic diagram of the optical lens 200 provided in the second embodiment of the present application, and the optical lens 200 in the embodiment is basically the same as that in the first embodiment, and the difference lies in that the object side S9 of the fifth lens is a convex surface near the optical axis, and the image side S10 is a concave surface near the optical axis, and other differences are shown in Table 3 and Table 4.

[0096] The related parameters of each lens in the optical lens 200 provided in the second embodiment of the present application are shown in Table 3.

[0097] Table 3

[0098]

[0099]

[0100] The surface type coefficients of the aspheric surfaces of the optical lens 200 in the embodiment are shown in Table 4.

[0101] Table 4

[0102]

[0103] In the embodiment, the structural diagram, the curve graph of the vertical axis chromatic aberration, the optical distortion and the axial aberration of the optical lens 200 are respectively shown in Figure 5 、 Figure 6 、 Figure 7 and Figure 8 . It can be seen from the figures that the vertical axis chromatic aberration is controlled within ±2 μm, which indicates that the vertical axis chromatic aberration of the optical lens 200 is well corrected; the optical distortion is controlled within ±27%, and the optical distortion of the field angle 0-48° is controlled within ±5%, which indicates that the distortion of the optical lens 200 is well corrected; the axial aberration of all wavelengths is controlled within ±0.025 mm, which indicates that the axial aberration of each field of the optical lens 200 is well corrected.

[0104] Third Embodiment

[0105] Please refer to Figure 9 , which is a structural schematic diagram of the optical lens 300 provided in the third embodiment of the present application. The optical lens 300 in the embodiment is generally the same as that in the first embodiment, and the difference lies in that the object side S9 of the fifth lens is a convex surface at the near optical axis, and other differences are shown in Table 5 and Table 6.

[0106] The related parameters of each lens in the optical lens 300 provided in the third embodiment of the present application are shown in Table 5.

[0107] Table 5

[0108]

[0109] The surface type coefficients of each aspheric surface of the optical lens 300 in the embodiment are shown in Table 6.

[0110] Table 6

[0111]

[0112]

[0113] In the embodiment, the structural diagram, the curve graph of the vertical axis chromatic aberration, the optical distortion and the axial aberration of the optical lens 300 are respectively shown in Figure 9 、 Figure 10 、 Figure 11 and Figure 12As shown in the figure, the chromatic aberration along the vertical axis is controlled within ±2μm, indicating that the chromatic aberration along the vertical axis of optical lens 300 is well corrected; optical distortion is controlled within ±25%, and optical distortion in the field of view of 0-48° is controlled within ±5%, indicating that the distortion of optical lens 300 is well corrected; axial aberration of all wavelengths is controlled within ±0.025mm, indicating that the axial aberration of optical lens 300 in each field of view is well corrected.

[0114] Fourth embodiment

[0115] Please see Figure 13 The figure shows a schematic diagram of the structure of the optical lens 400 provided in the fourth embodiment of the present invention. The optical lens 400 in this embodiment is generally the same as that in the first embodiment, except that the object side surface S5 of the third lens is concave and the object side surface S11 of the sixth lens is convex near the optical axis. Other differences are detailed in Tables 7 and 8.

[0116] The relevant parameters of each lens element in the optical lens 400 provided in the fourth embodiment of the present invention are shown in Table 7.

[0117] Table 7

[0118]

[0119]

[0120] The surface coefficients of each aspherical surface of the optical lens 400 in this embodiment are shown in Table 8.

[0121] Table 8

[0122]

[0123] In this embodiment, the structural diagram of the optical lens 400 and the curves of transverse chromatic aberration, optical distortion, and axial aberration are shown as follows: Figure 13 , Figure 14 , Figure 15 and Figure 16 As shown in the figure, the transverse chromatic aberration is controlled within ±2μm, indicating that the transverse chromatic aberration of the optical lens 400 is well corrected; the optical distortion is controlled within ±25%, and the optical distortion of the field of view 0-48° is controlled within ±5%, indicating that the distortion of the optical lens 400 is well corrected; the axial aberration of all wavelengths is controlled within ±0.04mm, indicating that the axial aberration of the optical lens 400 in each field of view is well corrected.

[0124] Table 9 is the optical characteristics of the above four embodiments, mainly including the effective focal length f of the system, the aperture number F#, the optical total length TTL, the maximum field of view angle FOV and the image height IH corresponding to FOV, and the numerical value corresponding to each of the above condition expressions.

[0125] Table 9

[0126]

[0127]

[0128] In summary, the optical lens provided by the present application adopts six aspheric lenses with specific optical powers, and through specific surface shape matching and reasonable optical power distribution, the maximum field of view angle FOV of the optical lens reaches 128°, the imaging range is wide, meanwhile, the six lenses are arranged compactly, the total length of the optical lens is reduced, and the optical lens has the advantages of large field of view angle, short total length and high imaging quality.

[0129] 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 description of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner.

[0130] The above-described embodiments only express several implementation manners of the present application, the description is more specific and detailed, but it cannot be understood as the limitation of the scope of the present application. It should be noted that for ordinary skilled in the art, without departing from the concept of the present application, several modifications and improvements can be made, which belong to the protection scope of the present application. Therefore, the protection scope of the present application should be subject to the appended claims.

Claims

1. An optical lens characterized in that, In order from the object side to the imaging plane along the optical axis, the optical lens comprises in sequence: a first lens, a diaphragm, a second lens, a third lens, a fourth lens, a fifth lens, a sixth lens and a filter; The first lens has negative refractive power, the object side surface of the first lens is concave at the vicinity of the optical axis, and the image side surface of the first lens is concave; The second lens has positive refractive power, the object side surface of the second lens is convex, and the image side surface of the second lens is convex; The third lens has negative refractive power, and the image side surface of the third lens is concave; The fourth lens has positive refractive power, the object side surface of the fourth lens is concave at the vicinity of the optical axis, and the image side surface of the fourth lens is convex; The fifth lens has positive refractive power; The sixth lens has negative refractive power, and the image side surface of the sixth lens is concave at the vicinity of the optical axis; The optical lens satisfies the following conditional expression: 0.3 < f4 / f < 0.5; Wherein, f4 represents the focal length of the fourth lens, and f represents the effective focal length of the optical lens.

2. The optical lens of claim 1, wherein, The optical lens satisfies the following conditional expression: 2 < f5 / f < 6; Wherein, f5 represents the focal length of the fifth lens, and f represents the effective focal length of the optical lens.

3. The optical lens of claim 1, wherein, The optical lens satisfies the following conditional expression: 1.7 < R41 / R42 < 2.9; Wherein, R41 represents the curvature radius of the object side surface of the fourth lens, and R42 represents the curvature radius of the image side surface of the fourth lens.

4. The optical lens of claim 1, wherein, The optical lens satisfies the following conditional expression: -1.5 < R21 / R22 < -0.9; 1.7 < CT2 / CT1 < 2.5; Wherein, R21 represents the curvature radius of the object side surface of the second lens, R22 represents the curvature radius of the image side surface of the second lens, CT2 represents the center thickness of the second lens, and CT1 represents the center thickness of the first lens.

5. The optical lens of claim 1, wherein, The optical lens satisfies the following conditional expression: 0.309 ≤ f4 / f ≤ 0.483; Wherein, f4 represents the focal length of the fourth lens, and f represents the effective focal length of the optical lens.

6. The optical lens of claim 1, wherein, The optical lens satisfies the following conditional expression: 0.8 < CT4 / CT5 < 1.1; -0.45 < SAG51 / CT5 < -0.25; Wherein, CT4 represents the center thickness of the fourth lens, CT5 represents the center thickness of the fifth lens, and SAG51 represents the sag of the object side surface of the fifth lens.

7. The optical lens of claim 1, wherein, The optical lens satisfies the following conditional expression: -0.2 < R62 / R61 < 0.1; Wherein, R62 represents the curvature radius of the image side surface of the sixth lens, and R61 represents the curvature radius of the object side surface of the sixth lens.

8. The optical lens of claim 1, wherein, The optical lens satisfies the following conditional expression: 0.06 < (CT23+CT34+CT45+CT56) / TTL < 0.08; Wherein, CT23 represents an air interval of the second lens and the third lens on the optical axis, CT34 represents an air interval of the third lens and the fourth lens on the optical axis, CT45 represents an air interval of the fourth lens and the fifth lens on the optical axis, CT56 represents an air interval of the fifth lens and the sixth lens on the optical axis, and TTL represents a distance from a lens object side of the first lens to an imaging plane on the optical axis.

9. The optical lens of claim 1, wherein, The optical lens satisfies the following conditional expression: -0.5 < (φ32-φ31) / (φ42-φ41) < -0.1; Wherein, φ32 represents a refractive power of an image side of the third lens, φ31 represents a refractive power of an object side of the third lens, φ42 represents a refractive power of an image side of the fourth lens, and φ41 represents a refractive power of an object side of the fourth lens.

10. The optical lens of claim 1, wherein, The optical lens satisfies the following conditional expression: 0.21 < FFL / TTL < 0.25; Wherein, FFL represents a distance from an image side of the sixth lens to an imaging plane on the optical axis, and TTL represents a distance from an object side of the first lens to an imaging plane on the optical axis.

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