Optical lens

Abstract

The present invention discloses an optical lens, which comprises, in order from the object plane to the image plane along the optical axis: a first lens having negative optical power, whose object side surface is concave at the near optical axis and whose image side surface is concave; an aperture; a second lens having positive optical power, whose object side surface is convex and whose image side surface is convex at the near optical axis; a third lens having negative optical power, whose image side surface is concave; a fourth lens having negative optical power, whose image side surface is concave at the near optical axis; a fifth lens having positive optical power, whose object side surface is convex at the near optical axis and whose image side surface is convex; a sixth lens having negative optical power, whose image side surface is concave at the near optical axis; and a filter having no optical power. The optical lens of the present invention uses six aspherical lenses having optical power and one filter having no optical power, and has at least the advantages of a large field of view, a short total length, and high resolution quality.

Description

Technical Field

[0001] The present invention relates to the technical field of imaging lenses, and in particular to an optical lens. Background Art

[0002] With the rapid advancement of technology in recent years, consumers have increasingly demanded higher image quality from smartphones and other mobile electronic products. Most mobile phone rear cameras are equipped with at least two lenses: a main camera and a wide-angle lens. However, existing wide-angle lenses typically utilize four to five elements, which cannot simultaneously meet the requirements of a wide field of view and a short overall length. Therefore, it is necessary to design an optical wide-angle lens that combines a large field of view with a short overall length and excellent image quality. Summary of the Invention

[0003] Based on this, the object of the present invention is to provide an optical lens having at least the advantages of a large field of view, a short total length and high imaging quality.

[0004] The present invention 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 optical power, whose object side surface is concave at the near optical axis and whose image side surface is also concave; an aperture; a second lens with positive optical power, whose object side surface is convex and whose image side surface is convex at the near optical axis; a third lens with negative optical power, whose image side surface is concave; a fourth lens with negative optical power, whose image side surface is concave at the near optical axis; a fifth lens with positive optical power, whose object side surface is convex at the near optical axis and whose image side surface is convex; a sixth lens with negative optical power, whose image side surface is concave at the near optical axis; and a filter without optical power.

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

[0006] Figure 1 A schematic structural diagram of an optical lens provided in a first embodiment of the present invention;

[0007] Figure 2 is a field curvature curve diagram of the optical lens in the first embodiment of the present invention;

[0008] Figure 3 is an optical distortion curve diagram of the optical lens in the first embodiment of the present invention;

[0009] Figure 4 is an axial aberration curve diagram of the optical lens in the first embodiment of the present invention;

[0010] Figure 5A schematic structural diagram of an optical lens provided in a second embodiment of the present invention;

[0011] Figure 6 is a field curvature curve diagram of the optical lens in the second embodiment of the present invention;

[0012] Figure 7 is an optical distortion curve diagram of the optical lens in the second embodiment of the present invention;

[0013] Figure 8 is an axial aberration curve diagram of the optical lens in the second embodiment of the present invention;

[0014] Figure 9 A schematic structural diagram of an optical lens provided in a third embodiment of the present invention;

[0015] Figure 10 is a field curvature curve diagram of the optical lens in the third embodiment of the present invention;

[0016] Figure 11 is an optical distortion curve diagram of the optical lens in the third embodiment of the present invention;

[0017] Figure 12 is an axial aberration curve diagram of the optical lens in the third embodiment of the present invention;

[0018] Figure 13 A schematic structural diagram of an optical lens provided in a fourth embodiment of the present invention;

[0019] Figure 14 is a field curvature curve diagram of the optical lens in the fourth embodiment of the present invention;

[0020] Figure 15 is an optical distortion curve diagram of the optical lens in the fourth embodiment of the present invention;

[0021] Figure 16 4 is an axial aberration curve diagram of the optical lens in the fourth embodiment of the present invention. DETAILED DESCRIPTION

[0022] To facilitate understanding of the present invention, the present invention will be described more fully below with reference to the accompanying drawings. The drawings illustrate several embodiments of the present invention. However, the present invention may be implemented in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided to provide a more thorough and comprehensive understanding of the present invention.

[0023] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art to which the present invention pertains. The terms used in this specification are for the purpose of describing specific embodiments only and are not intended to limit the present invention. Throughout the specification, the same reference numerals refer to the same elements.

[0024] The present invention provides an optical lens, which includes, along the optical axis from the object side to the imaging surface, a first lens, an aperture, a second lens, a third lens, a fourth lens, a fifth lens, a sixth lens and a filter.

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

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

[0027] 2.2 <CT5 / CT6<2.8; (1)

[0028] Wherein, CT5 represents the center thickness of the fifth lens, and CT6 represents the center thickness of the sixth lens. Satisfying the above conditional equation (1) and reasonably controlling the ratio of the center thickness of the fifth lens to the center thickness of the sixth lens facilitates lens molding processing, reduces lens molding tolerances, and improves the yield rate of the optical lens.

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

[0030] 0.8 <f2 / f<1.0; (2)

[0031] Wherein, f2 represents the focal length of the second lens, and f represents the effective focal length of the optical lens. Satisfying the above conditional equation (2) and rationally controlling the ratio of the focal length of the second lens to the effective focal length of the optical lens is beneficial for converging the light in each field of view, correcting the aberrations in each field of view, and improving the imaging quality of the optical lens.

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

[0033] -32 <CT1 / SAG11<-7; (3)

[0034] Wherein, CT1 represents the center thickness of the first lens, and SAG11 represents the sagittal height of the object side of the first lens. Satisfying the above conditional equation (3) and rationally controlling the ratio of the center thickness of the first lens to the sagittal height of the object side of the first lens can help reduce the incident angle of light entering the aperture, thereby increasing the field of view of the optical lens.

[0035] In some embodiments, the optical lens satisfies the following conditional formula:

[0036] 2.0<(CT2+CT23) / CT3<2.25; (4)

[0037] Wherein, CT2 represents the center thickness of the second lens, CT23 represents the air gap between the second lens and the third lens on the optical axis, and CT3 represents the center thickness of the third lens. Satisfying the above conditional equation (4) and rationally controlling the relationship between the center thickness of the second lens, the air gap between the second lens and the third lens, and the center thickness of the third lens can help make the second and third lenses more compact, reduce the total length of the optical lens, and facilitate miniaturization of the optical lens.

[0038] In some embodiments, the optical lens satisfies the following conditional formula:

[0039] 0.5<(φ41+φ42) / (φ31+φ32)<5.5; (5)

[0040] 0.25<(CT3+CT34+CT4) / CTa<0.35; (6)

[0041] Wherein, φ41 represents the optical power of the object side of the fourth lens, φ42 represents the optical power of the image side of the fourth lens, φ31 represents the optical power of the object side of the third lens, φ32 represents the optical power of the image side of the third lens, CT3 represents the center thickness of the third lens, CT34 represents the air gap between the third lens and the fourth lens on the optical axis, CT4 represents the center thickness of the fourth lens, and CTa represents the sum of the center thicknesses of the first lens to the sixth lens. Simultaneously satisfying the above-mentioned conditional equations (5) and (6), by reasonably controlling the optical power of the third lens and the fourth lens, and the relationship between the distance from the object side of the third lens to the image side of the fourth lens and the sum of the center thicknesses of the first lens to the sixth lens, it is beneficial to make the third lens and the fourth lens more compact, to reduce the total length of the optical lens, and to achieve miniaturization of the optical lens.

[0042] In some embodiments, the optical lens satisfies the following conditional formula:

[0043] 6.0<φ52 / φ51<7.5; (7)

[0044] Wherein, φ52 represents the optical power of the image side surface of the fifth lens, and φ51 represents the optical power of the object side surface of the fifth lens. Satisfying the above conditional equation (7) and rationally controlling the optical power of the fifth lens is beneficial to controlling the effective focal length of the optical lens and increasing the field of view angle of the optical lens.

[0045] In some embodiments, the optical lens satisfies the following conditional formula:

[0046] 0.8 <f6 / f1<1.0; (8)

[0047] Wherein, f6 represents the focal length of the sixth lens, and f1 represents the focal length of the first lens. Satisfying the above conditional equation (8) and rationally controlling the focal length of the sixth lens facilitates correction of field curvature and coma of the off-axis field of view, thereby improving the imaging quality of the optical lens.

[0048] In some embodiments, the optical lens satisfies the following conditional formula:

[0049] 0.4<φ31×R31×φ41×R41<0.5; (9)

[0050] Wherein, φ31 represents the optical power of the object side of the third lens, R31 represents the radius of curvature of the object side of the third lens, φ41 represents the optical power of the object side of the fourth lens, and R41 represents the radius of curvature of the object side of the fourth lens. Satisfying the above conditional equation (9) and rationally controlling the relationship between the optical power and curvature radius of the object side of the third lens and the fourth lens is beneficial for diverging the light of the outer field of view, thereby reducing the total length of the optical lens and facilitating miniaturization of the optical lens.

[0051] In some embodiments, the optical lens satisfies the following conditional formula:

[0052] -0.95<(φ61-φ62) / (φ51-φ52)<-0.70; (10)

[0053] Wherein, φ61 represents the focal power of the object side of the sixth lens, φ62 represents the focal power of the image side of the sixth lens, φ51 represents the focal power of the object side of the fifth lens, and φ52 represents the focal power of the image side of the fifth lens. Satisfying the above conditional equation (10) and rationally controlling the relationship between the focal powers of the fifth and sixth lenses is beneficial for correcting spherical aberration of the optical lens and improving the imaging quality of the optical lens.

[0054] In some embodiments, the optical lens satisfies the following conditional formula:

[0055] -16<(f3×f4) / (f1×f2)<-7; (11)

[0056] Wherein, f3 represents the focal length of the third lens, f4 represents the focal length of the fourth lens, f1 represents the focal length of the first lens, and f2 represents the focal length of the second lens. Satisfying the above conditional equation (11) and rationally controlling the relationship between the focal lengths of the first lens and the fourth lens is beneficial for correcting the spherical aberration of the optical lens and improving the imaging quality of the optical lens.

[0057] In some embodiments, the optical lens satisfies the following conditional formula:

[0058] 0.9<(SAG12-SAG11) / CT1<1.2; (12)

[0059] Wherein, SAG12 represents the sagittal height of the image side surface of the first lens, SAG11 represents the sagittal height of the object side surface of the first lens, and CT1 represents the center thickness of the first lens. Satisfying the above conditional equation (12) and rationally controlling the relationship between the sagittal height and the center thickness of the first lens can help reduce the incident angle of light entering the aperture, thereby increasing the field of view of the optical lens.

[0060] In some embodiments, the optical lens satisfies the following conditional formula:

[0061] -20 <SAG52 / SAG51<-12; (13)

[0062] 0.5<(SAG51-SAG52) / CT5<0.7; (14)

[0063] Wherein, SAG51 represents the sagittal height of the object side surface of the fifth lens, SAG52 represents the sagittal height of the image side surface of the fifth lens, and CT5 represents the center thickness of the fifth lens. Simultaneously satisfying the above-mentioned conditional equations (13) and (14) and rationally controlling the relationship between the sagittal height and the center thickness of the fifth lens facilitates correcting the aberrations of each field of view separately, thereby improving the imaging quality of the optical lens.

[0064] In some embodiments, the optical lens satisfies the following conditional formula:

[0065] 0.8 <SAG61 / SAG62<1.2; (15)

[0066] -0.1<(SAG61-SAG62) / CT6<0.1; (16)

[0067] Wherein, SAG61 represents the sagittal height of the object side surface of the sixth lens, SAG62 represents the sagittal height of the image side surface of the sixth lens, and CT6 represents the center thickness of the sixth lens. Simultaneously satisfying the above-mentioned conditional equations (15) and (16) and rationally controlling the relationship between the sagittal height and the center thickness of the sixth lens is beneficial for correcting the field curvature of the off-axis field of view and improving the imaging quality of the optical lens.

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

[0069] 0.24 <FFL / TTL<0.26; (17)

[0070] Wherein, FFL represents the distance from the image side of the sixth lens to the imaging plane on the optical axis, and TTL represents the distance from the object side of the first lens to the imaging plane on the optical axis. Satisfying the above conditional equation (17) and rationally controlling the relationship between the optical back focus and the total optical length of the optical lens can help reduce the risk of interference between the mechanism and the lens, thereby facilitating the mechanical design of the product.

[0071] In various embodiments of the present invention, when the lens is an aspheric lens, the surface shape of the aspheric lens satisfies the following equation:

[0072]

[0073] Where z is the distance from the aspheric surface vertex to the height h along the optical axis, c is the paraxial curvature of the surface, k is the conic coefficient, A 2i is the 2i-order aspheric surface coefficient.

[0074] 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.

[0075] First embodiment

[0076] See also Figure 1 , shown is a schematic structural diagram of the optical lens 100 provided in the first embodiment of the present invention, wherein the optical lens 100 includes, along the optical axis from the object side to the imaging surface S15, a first lens L1, an aperture 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.

[0077] Specifically, the first lens L1 has 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 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 at the near optical axis; the third lens L3 has 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 negative focal power. The fourth lens has a convex object-side surface S7 near the optical axis, and a concave image-side surface S8 near the optical axis. The fifth lens L5 has positive power, a convex object-side surface S9, and a convex image-side surface S10. The sixth lens L6 has negative power, a concave object-side surface S11, and a concave image-side surface S12 near the optical axis. The filter G1 has an object-side surface S13 and an image-side surface S14. Lenses L1 through L6 are all plastic aspherical lenses.

[0078] Table 1 shows the parameters of each lens in the optical lens 100 provided in the first embodiment of the present invention.

[0079] Table 1

[0080]

[0081]

[0082] The surface coefficients of the aspheric surfaces of the optical lens 100 in this embodiment are shown in Table 2.

[0083] Table 2

[0084]

[0085]

[0086] In this embodiment, the structure diagram, field curvature, optical distortion and axial aberration curves of the optical lens 100 are shown as follows: Figure 1 、 Figure 2 、 Figure 3 and Figure 4 shown.

[0087] Figure 2 The field curvature curve of the optical lens 100 in this embodiment is shown, which represents the field curvature values at different fields of view. It can be seen from the figure that the field curvature value at each field of view is controlled within ±0.15mm, indicating that the field curvature of each field of view of the optical lens 100 is well corrected.

[0088] Figure 3The optical distortion curve of the optical lens 100 of this embodiment is shown, which represents the distortion at different fields of view on the imaging surface. It can be seen from the figure that the optical distortion is controlled within ±25%, indicating that the distortion of the optical lens 100 is well corrected.

[0089] Figure 4 The axial aberration curve of the optical lens 100 in this embodiment is shown, which represents the aberration of different wavelengths in the optical axis direction. It can be seen from the figure that the axial aberration of all wavelengths is controlled within ±0.025mm, indicating that the axial aberration of the optical lens 100 is well corrected.

[0090] Second embodiment

[0091] See also Figure 5 , shown is a schematic structural diagram of the optical lens 200 provided in the second embodiment of the present invention. The optical lens 200 in this embodiment is substantially the same as that in the first embodiment, except that the object-side surface S5 of the third lens is concave. Other differences are detailed in Tables 3 and 4.

[0092] Table 3 shows the parameters of each lens in the optical lens 200 provided in the second embodiment of the present invention.

[0093] Table 3

[0094]

[0095]

[0096] The surface coefficients of the aspheric surfaces of the optical lens 200 in this embodiment are shown in Table 4.

[0097] Table 4

[0098]

[0099] In this embodiment, the structure diagram, field curvature, optical distortion and axial aberration curves of the optical lens 200 are shown in FIG. Figure 5 、 Figure 6 、 Figure 7 and Figure 8 As shown in the figure, it can be seen that the field curvature is controlled within ±0.12mm, indicating that the field curvature of the optical lens 200 is well corrected; the optical distortion is controlled within ±25%, indicating that the distortion of the optical lens 200 is well corrected; and the axial aberration of all wavelengths is controlled within ±0.03mm, indicating that the axial aberration of each field of view of the optical lens 200 is well corrected.

[0100] Third embodiment

[0101] See also Figure 9, shown is a schematic structural diagram of the optical lens 300 provided in the third embodiment of the present invention. The optical lens 300 in this embodiment is substantially the same as that in the first embodiment, except that the object-side surface S7 of the fourth lens is concave at the near optical axis, and the object-side surface S11 of the sixth lens is convex at the near optical axis. Other differences are detailed in Tables 5 and 6.

[0102] Table 5 shows the parameters of each lens in the optical lens 300 provided in the third embodiment of the present invention.

[0103] Table 5

[0104]

[0105] The surface coefficients of the aspheric surfaces of the optical lens 300 in this embodiment are shown in Table 6.

[0106] Table 6

[0107]

[0108]

[0109] In this embodiment, the structure diagram, field curvature, optical distortion and axial aberration curves of the optical lens 300 are shown as follows: Figure 9 、 Figure 10 、 Figure 11 and Figure 12 As shown in the figure, it can be seen that the field curvature is controlled within ±0.15mm, indicating that the field curvature of the optical lens 300 is well corrected; the optical distortion is controlled within ±27%, indicating that the distortion of the optical lens 300 is well corrected; and the axial aberration of all wavelengths is controlled within ±0.032mm, indicating that the axial aberration of each field of view of the optical lens 300 is well corrected.

[0110] Fourth embodiment

[0111] See also Figure 13 , shown is a schematic structural diagram of an optical lens 400 provided in a fourth embodiment of the present invention. The optical lens 400 in this embodiment is substantially the same as that in the first embodiment, except that the object-side surface S7 of the fourth lens is concave at the near optical axis, and the object-side surface S11 of the sixth lens is convex at the near optical axis. For other differences, please see Tables 7 and 8 for details.

[0112] Table 7 shows the parameters of each lens in the optical lens 400 provided in the fourth embodiment of the present invention.

[0113] Table 7

[0114]

[0115]

[0116] The surface coefficients of the aspheric surfaces of the optical lens 400 in this embodiment are shown in Table 8.

[0117] Table 8

[0118]

[0119] In this embodiment, the structure diagram, field curvature, optical distortion and axial aberration curves of the optical lens 400 are shown as follows: Figure 13 、 Figure 14 、 Figure 15 and Figure 16 As shown in the figure, it can be seen that the field curvature is controlled within ±0.15mm, indicating that the field curvature of the optical lens 400 is well corrected; the optical distortion is controlled within ±25%, indicating that the distortion of the optical lens 400 is well corrected; and the axial aberration of all wavelengths is controlled within ±0.032mm, indicating that the axial aberration of each field of view of the optical lens 400 is well corrected.

[0120] Table 9 shows the optical characteristics corresponding to the above four embodiments, mainly including the system's effective focal length f, aperture number F#, total optical length TTL, maximum field of view FOV, image height IH corresponding to FOV, and the numerical values corresponding to each of the above conditional expressions.

[0121] Table 9

[0122]

[0123] In summary, the optical lens provided by the present invention uses six aspheric lenses with specific optical powers. Through the specific surface shape combination and reasonable optical power distribution, the maximum field of view (FOV) of the optical lens reaches 128°, and the imaging range is wide. At the same time, the six lenses are arranged compactly, reducing the overall length of the optical lens. As a result, the optical lens has the advantages of a large field of view, a short total length, and high imaging quality.

[0124] 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.

[0125] The above-described embodiments merely illustrate several embodiments of the present invention, and while the 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 various modifications 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, characterized in that: Along the optical axis, from the object side to the imaging surface, it includes: a first lens, an aperture, a second lens, a third lens, a fourth lens, a fifth lens, a sixth lens, and a filter; The first lens has negative optical power, the object side surface of the first lens is concave at the near 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 near the optical axis; The third lens has negative optical power, and the image side surface of the third lens is concave; The fourth lens has negative optical power, and the image side surface of the fourth lens is concave at the near optical axis; The fifth lens has positive refractive power, the object side surface of the fifth lens is convex at the near optical axis, and the image side surface of the fifth lens is convex; The sixth lens has negative optical power, and the image side surface of the sixth lens is concave at the near optical axis; The optical lens satisfies the following conditional formula: 6.0<φ52 / φ51<7.5; Wherein, φ52 represents the optical power of the image-side surface of the fifth lens, and φ51 represents the optical power of the object-side surface of the fifth lens.

2. The optical lens according to claim 1, wherein: The optical lens satisfies the following conditional formula: 2.2 <CT5 / CT6<2.8; Wherein, CT5 represents the center thickness of the fifth lens, and CT6 represents the center thickness of the sixth lens.

3. The optical lens according to claim 1, wherein: The optical lens satisfies the following conditional formula: 0.8 <f2 / f<1.0; Wherein, f2 represents the focal length of the second lens, and f represents the effective focal length of the optical lens.

4. The optical lens according to claim 1, wherein: The optical lens satisfies the following conditional formula: -32 <CT1 / SAG11<-7; Wherein, CT1 represents the center thickness of the first lens, and SAG11 represents the sag height of the object side of the first lens.

5. The optical lens according to claim 1, wherein: The optical lens satisfies the following conditional formula: 2.0<(CT2+CT23) / CT3<2.25; Wherein, CT2 represents the center thickness of the second lens, CT23 represents the air gap between the second lens and the third lens on the optical axis, and CT3 represents the center thickness of the third lens.

6. The optical lens according to claim 1, wherein: The optical lens satisfies the following conditional formula: 0.5<(φ41+φ42) / (φ31+φ32)<5.5; 0.25<(CT3+CT34+CT4) / CTa<0.35; Wherein, φ41 represents the optical power of the object side surface of the fourth lens, φ42 represents the optical power of the image side surface of the fourth lens, φ31 represents the optical power of the object side surface of the third lens, φ32 represents the optical power of the image side surface of the third lens, CT3 represents the center thickness of the third lens, CT34 represents the air gap between the third lens and the fourth lens on the optical axis, CT4 represents the center thickness of the fourth lens, and CTa represents the sum of the center thicknesses of each lens from the first lens to the sixth lens.

7. The optical lens according to claim 1, wherein: The optical lens satisfies the following conditional formula: -16<(f3×f4) / (f1×f2)<-7; Wherein, f3 represents the focal length of the third lens, f4 represents the focal length of the fourth lens, f1 represents the focal length of the first lens, and f2 represents the focal length of the second lens.

8. The optical lens according to claim 1, wherein: The optical lens satisfies the following conditional formula: 0.8 <f6 / f1<1.0; Wherein, f6 represents the focal length of the sixth lens, and f1 represents the focal length of the first lens.

9. The optical lens according to claim 1, wherein: The optical lens satisfies the following conditional formula: 0.4<φ31×R31×φ41×R41<0.5; Among them, φ31 represents the optical focal length of the third lens objective side, R31 represents the curvature radius of the third lens objective side, φ41 represents the optical focal length of the fourth lens objective side, and R41 represents the curvature radius of the fourth lens objective side.

10. The optical lens according to claim 1, wherein: The optical lens satisfies the following conditional formula: -0.95<(φ61-φ62) / (φ51-φ52)<-0.70; Among them, φ61 represents the optical focal length of the object side of the sixth lens, φ62 represents the optical focal length of the image side of the sixth lens, φ51 represents the optical focal length of the object side of the fifth lens, and φ52 represents the optical focal length of the image side of the fifth lens.

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