An eight-element large aperture imaging lens

Abstract

The present invention relates to an eight-piece large aperture imaging lens, characterized in that it includes a first lens, a second lens, a third lens, a fourth lens, a fifth lens, a sixth lens, a seventh lens, and an eighth lens in order from the object side to the image side, and the eight-piece large aperture imaging lens satisfies the following relationship: TTL / ImgH<0.84; wherein TTL is the distance from the object side of the first lens at the near optical axis to the imaging surface, and ImgH is the length of the diagonal of the effective imaging area of ​​the eight-piece large aperture imaging lens. The imaging quality of the present invention is high, the volume is light and thin, and it has a large aperture and a large field of view.

Description

Technical Field

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

[0002] In recent years, optical imaging lenses have been continuously evolving, and their application scope has become wider. In addition to requiring the lenses to be thin, light and short, the requirements for the imaging quality of the lenses are also getting higher and higher. In order to improve the imaging quality, it is necessary to increase the number of optical lenses to modify problems such as aberrations and dispersion. However, with the increase in the number of optical lenses, the distance from the object side surface of the first lens to the imaging surface on the optical axis will increase, which is not conducive to the thinning of mobile phones, digital cameras and automotive lenses. Therefore, designing a multi-lens optical imaging lens with good imaging quality and thinness has always been the goal of the industry. Although the imaging quality of the existing eight-piece imaging lens is better than that of the general five-piece or six-piece lens, its volume is also relatively large and cannot meet the requirements for lens thinning. In addition, a large aperture is conducive to increasing the light flux, and a large field of view angle has gradually become a market trend. The aperture and field of view angle of the existing eight-piece imaging lens cannot meet the growing market demand. Summary of the invention

[0003] The object of the present invention is to provide an eight-element large aperture imaging lens, which has high imaging quality, is light and thin, and has a large aperture and a large field of view.

[0004] An eight-element large aperture imaging lens, characterized in that it includes, from the object side to the image side, in order: a first lens with positive refractive power, whose object side surface is convex at the near optical axis, and whose image side surface is concave at the near optical axis; a second lens with negative refractive power, whose object side surface is convex at the near optical axis, and whose image side surface is concave at the near optical axis; a third lens with positive refractive power, whose object side surface is convex at the near optical axis, and whose image side surface is concave at the near optical axis; a fourth lens with negative refractive power, whose object side surface is concave at the near optical axis; a fifth lens with negative refractive power, whose image side surface is concave at the near optical axis; a lens having positive refractive power The sixth lens has an object-side surface that is convex at the near optical axis, and an image-side surface that is concave at the near optical axis; the seventh lens has a positive refractive power, and its object-side surface is convex at the near optical axis, and its image-side surface is concave at the near optical axis; the eighth lens has a negative refractive power, and its object-side surface is concave at the near optical axis, and its image-side surface is concave at the near optical axis; the eight-piece large aperture imaging lens satisfies the following relationship: TTL / ImgH<0.84; wherein TTL is the distance from the object side of the first lens at the near optical axis to the imaging plane, and ImgH is the length of the diagonal of the effective imaging area of ​​the eight-piece large aperture imaging lens.

[0005] In the above structure, the object-side surface of the first lens is convex near the optical axis, which can effectively balance the low-order aberrations. The second lens has a negative refractive power, which is beneficial to eliminating the aberrations generated by the first lens. The third lens has a positive refractive power, the fourth lens has a negative refractive power, the fifth lens has a negative refractive power, the sixth lens has a positive refractive power, and the seventh lens has a positive refractive power, which can effectively correct the paraxial spherical aberration and reduce the astigmatism field curvature at the periphery. The eighth lens has a negative refractive power and the image-side surface is concave near the optical axis, which helps to move the principal point of the optical imaging system away from the image-side end, thereby effectively shortening the overall length of the optical imaging system, facilitating the miniaturization of the system, and at the same time correcting the off-axis aberrations to improve the peripheral imaging quality.

[0006] Further, the eight-element large-aperture imaging lens satisfies the relationship: ND2≧1.68, ND1 = ND3 = ND5 = ND6 = ND7; where ND1, ND2, ND3, ND5, ND6, and ND7 are the refractive indices of the first lens, the second lens, the third lens, the fifth lens, the sixth lens, and the seventh lens, respectively. The above refractive index relationship is beneficial to ensuring the imaging quality of the lens.

[0007] Further, the eight-element large-aperture imaging lens satisfies the relationship: -3.3 < R72 / R81 < -2.25; where R72 is the radius of curvature of the image-side surface of the seventh lens, and R81 is the radius of curvature of the object-side surface of the eighth lens. The above ratio range of the radii of curvature can effectively balance astigmatism and coma, making the imaging quality of the lens better.

[0008] Further, the eight-element large-aperture imaging lens satisfies the relationship: 0.22 ≦ T67 / CT1 < 0.26; where T67 is the distance between the sixth lens and the seventh lens on the optical axis, and CT1 is the maximum thickness of the first lens on the optical axis. By controlling the ratio of the distance between the sixth lens and the seventh lens on the optical axis to the maximum thickness of the first lens on the optical axis, the spacing between the lenses can be appropriately allocated, the total length of the camera lens can be reduced, and the assembly difficulty of the camera lens can be lowered, enabling the assembly process to proceed smoothly and simply.

[0009] Further, the eight-element large-aperture imaging lens satisfies the relationship: 0.22 < (f8 - f7) / (f2 - f1) < 0.34; where f1 is the focal length of the first lens, f2 is the focal length of the second lens, f7 is the focal length of the seventh lens, and f8 is the focal length of the eighth lens. By controlling the focal length ratio, the optical imaging lens can have better aberration correction ability.

[0010] Further, the eight-piece large-aperture imaging lens satisfies the relation: 0.65 < CT1 / (CT4 + CT5) ≦ 1.14; where CT1 is the maximum thickness of the first lens on the optical axis, CT4 is the maximum thickness of the fourth lens on the optical axis, and CT5 is the maximum thickness of the fifth lens on the optical axis. The ratio of the maximum thicknesses of the above lenses is conducive to reducing the volume of the lens and achieving miniaturization of the lens.

[0011] Further, the eight-piece large-aperture imaging lens satisfies the relation: -2.88 < f5 / f6 < -0.16; where f5 is the focal length of the fifth lens and f6 is the focal length of the sixth lens. Satisfying the above relation can reasonably distribute the bending force of the lenses, effectively shorten the total length of the camera lens while ensuring the imaging quality.

[0012] Further, the eight-piece large-aperture imaging lens satisfies the relation: 0.51 < f / f1 < 0.84; where f is the effective focal length of the eight-piece large-aperture imaging lens and f1 is the focal length of the first lens. By controlling the ratio of the effective focal length of the entire system to the focal length of the first lens, it is possible to avoid excessive optical power of the first lens, resulting in a low-sensitivity and good-imaging-quality optical imaging lens, and at the same time, the optical imaging lens has a short optical length.

[0013] Further, the eight-piece large-aperture imaging lens satisfies the relation: -4.94 < f4 / f < -3.31; where f is the effective focal length of the eight-piece large-aperture imaging lens and f4 is the focal length of the fourth lens. By controlling the ratio of the focal length of the fourth lens to the effective focal length of the entire system, it is possible to avoid excessive optical power of the fourth lens, resulting in a low-sensitivity and good-imaging-quality optical imaging lens, and at the same time, the optical imaging lens has a short optical length.

[0014] Further, the eight-piece large-aperture imaging lens satisfies the relation: 0.08 < CT5 / TTL < 0.15; where CT5 is the maximum thickness of the fifth lens on the optical axis and TTL is the distance from the object side surface of the first lens at the near optical axis to the imaging surface. Satisfying the above relation is conducive to controlling the thickness of the fifth lens on the optical axis and reducing the sensitivity of the optical imaging lens.

[0015] Further, the eight-piece large-aperture imaging lens satisfies the relation: f / EPD ≦ 1.48; where EPD is the entrance pupil diameter and f is the effective focal length of the eight-piece large-aperture imaging lens. By controlling the above ratio to expand the aperture and increase the light transmission amount, a better imaging effect can be achieved.

[0016] Compared with the prior art, the invention has the following beneficial effects: by adopting an eight-piece lens combination and by reasonably matching the refractive force, the overall length of the lens is effectively shortened while ensuring the high imaging quality of the lens, so that the lens meets the requirements of thinness. The reasonable matching of parameters between the various lenses makes the lens have the characteristics of large aperture and large field of view, meeting people's shooting needs in low light environment and wide angle. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 Schematic diagram of the structure of the first embodiment of the eight-element large aperture imaging lens of the present invention.

[0018] Figure 2 Graph showing astigmatism and distortion of the first embodiment of the eight-element large aperture imaging lens of the present invention.

[0019] Figure 3 Graph showing the spherical aberration of the first embodiment of the eight-element large aperture imaging lens of the present invention.

[0020] Figure 4 Schematic diagram of the structure of the second embodiment of the eight-element large aperture imaging lens of the present invention.

[0021] Figure 5 Graph showing astigmatism and distortion of the second embodiment of the eight-element large aperture imaging lens of the present invention.

[0022] Figure 6 This is a spherical aberration curve diagram of the second embodiment of the eight-element large aperture imaging lens of the present invention.

[0023] Figure 7 Schematic diagram of the structure of the third embodiment of the eight-element large aperture imaging lens of the present invention.

[0024] Figure 8 Graph showing astigmatism and distortion of the third embodiment of the eight-element large aperture imaging lens of the present invention.

[0025] Fig. 9 Graph showing the spherical aberration of the third embodiment of the eight-element large aperture imaging lens system of the present invention.

[0026] Fig.10 Schematic diagram of the structure of a fourth embodiment of an eight-element large aperture imaging lens according to the present invention.

[0027] Fig.11 Graph showing astigmatism and distortion of the fourth embodiment of the eight-element large aperture imaging lens of the present invention.

[0028] Fig.12 Graph showing the spherical aberration of the fourth embodiment of the eight-element large aperture imaging lens system of the present invention.

[0029] Fig.13Schematic diagram of the structure of the fifth embodiment of the eight-element large aperture imaging lens of the present invention.

[0030] Fig.14 Graph showing astigmatism and distortion of the fifth embodiment of the eight-element large aperture imaging lens of the present invention.

[0031] Fig.15 Graph showing the spherical aberration of the fifth embodiment of the eight-element large aperture imaging lens system of the present invention.

[0032] Fig.16 Schematic diagram of the structure of the sixth embodiment of the eight-element large aperture imaging lens of the present invention.

[0033] Fig.17 Graph showing astigmatism and distortion of the sixth embodiment of the eight-element large aperture imaging lens of the present invention.

[0034] Fig.18 Graph showing the spherical aberration of the sixth embodiment of the eight-element large aperture imaging lens system of the present invention. DETAILED DESCRIPTION

[0035] In order to facilitate the understanding of the present invention, the present invention will be described more fully below with reference to the relevant drawings. The drawings show preferred embodiments of the present invention. However, the present invention can be implemented in many different forms and is not limited to the embodiments described herein.

[0036] In the description of the present invention, the object side refers to the side of the lens facing the subject, and the image side refers to the side of the lens facing the imaging surface. When a section is made at any point on the object side surface of the lens, the surface is always located on the image side of the section, and its curvature radius is positive, then the object side surface of the lens is convex; otherwise, the object side surface of the lens is concave, and its curvature radius is negative.

[0037] When a section is made at any point on the image-side surface of the lens, the surface is always on the object side of the section, and its radius of curvature is negative, then the image-side surface of the lens is convex; otherwise, the image-side surface of the lens is concave, and its radius of curvature is positive.

[0038] If a section is made at any point on the object side surface or image side surface of the lens, and the surface has part on the image side and part on the object side of the section, then there is an inflection point on the surface. The above method still applies to judging the convexity of the object side and image side surfaces near the optical axis.

[0039] In addition, the aspheric curve equation of each lens is expressed as follows:

[0040]

[0041] Among them, Z is the distance vector height from the origin of the aspherical surface when the aspherical surface is at a height r along the optical axis direction, c is the paraxial curvature of the aspherical surface (the radius of curvature R = 1 / c, which is the inverse of the curvature); k is the cone coefficient; Ai is the i-th order coefficient of the aspherical surface, and the high-order coefficients used in the present invention are A4, A6, A8, A10, A12, A14, A16, A18, and A20.

[0042] Please refer to Figure 1 In the first embodiment, the eight-lens large aperture imaging lens of the present invention includes, from the object side to the image side, an aperture 10, a first lens 11, a second lens 12, a third lens 13, a fourth lens 14, a fifth lens 15, a sixth lens 16, a seventh lens 17, an eighth lens 18, and a filter 19. There is a spacing distance between two adjacent lenses, and there is no relative movement between the lenses. The object side surface and the image side surface of the first lens 11, the second lens 12, the third lens 13, the fourth lens 14, the fifth lens 15, the sixth lens 16, the seventh lens 17, and the eighth lens 18 are all aspherical surfaces.

[0043] Specifically, the first lens 11 has positive refractive power, its object side surface is convex at the near optical axis, and its image side surface is concave at the near optical axis; the second lens 12 has negative refractive power, its object side surface is convex at the near optical axis, and its image side surface is concave at the near optical axis; the third lens 13 has positive refractive power, its object side surface is convex at the near optical axis, and its image side surface is concave at the near optical axis; the fourth lens 14 has negative refractive power, its object side surface is concave at the near optical axis, and its image side surface can be set to convex or concave near the optical axis according to actual needs. The fifth lens 15 has negative refractive power, its image side surface is concave at the near optical axis, and its object side surface can be set to convex or concave at the near optical axis according to actual needs; the sixth lens 16 has positive refractive power, its object side surface is convex at the near optical axis, and its image side surface is concave at the near optical axis; the seventh lens 17 has positive refractive power, its object side surface is convex at the near optical axis, and its image side surface is concave at the near optical axis; the eighth lens 18 has negative refractive power, its object side surface is concave at the near optical axis, and its image side surface is concave at the near optical axis.

[0044] In the above structure, the object-side surface of the first lens 11 is convex near the optical axis, and its image-side surface is concave near the optical axis, which can effectively balance the low-order aberrations. The second lens 12 has a negative refractive power, which is beneficial to eliminating the aberrations generated by the first lens 11. The third lens 13 has a positive refractive power, the fourth lens 14 has a negative refractive power, the fifth lens 15 has a negative refractive power, the sixth lens 16 has a positive refractive power, and the seventh lens 17 has a positive refractive power. The above combination of refractive powers can effectively correct the paraxial spherical aberration and reduce the astigmatism field curvature at the periphery. The eighth lens 18 has a negative refractive power and its image-side surface is concave near the optical axis, which helps to move the principal point of the optical imaging system away from the image-side end, thereby effectively shortening the overall length of the optical imaging system, being beneficial to the miniaturization of the system, and at the same time can correct the off-axis aberrations to improve the peripheral imaging quality.

[0045] The above eight-element large-aperture imaging lens satisfies the following condition: TTL / ImgH < 0.84, where TTL is the distance from the object-side surface of the first lens 11 near the optical axis to the imaging surface, and ImgH is the length of the diagonal of the effective imaging area of the eight-element large-aperture imaging lens. By controlling the ratio of TTL / ImgH, it can be ensured that the optical imaging lens has the characteristics of a large image plane and thinning.

[0046] Preferably, the above eight-element large-aperture imaging lens satisfies the relationship: ND2 ≧ 1.68, ND1 = ND3 = ND5 = ND6 = ND7; where ND1, ND2, ND3, ND5, ND6, and ND7 are the refractive indices of the first lens 11, the second lens 12, the third lens 13, the fifth lens 15, the sixth lens 16, and the seventh lens 17, respectively. The above relationship of refractive indices is beneficial to ensuring the imaging quality of the lens.

[0047] Preferably, the above eight-element large-aperture imaging lens satisfies the relationship: -3.3 < R72 / R81 < -2.25; where R72 is the radius of curvature of the image-side surface of the seventh lens 17, and R81 is the radius of curvature of the object-side surface of the eighth lens 18. The above range of the ratio of the radii of curvature can effectively balance astigmatism and coma, making the imaging quality of the lens better.

[0048] Preferably, the above eight-element large-aperture imaging lens satisfies the relationship: 0.22 ≦ T67 / CT1 < 0.26; where T67 is the distance between the sixth lens 16 and the seventh lens 17 on the optical axis, and CT1 is the maximum thickness of the first lens 11 on the optical axis. By controlling the ratio of the distance between the sixth lens 16 and the seventh lens 17 on the optical axis to the maximum thickness of the first lens 11 on the optical axis, the distance between the lenses can be appropriately distributed, reducing the total length of the camera lens and the assembly difficulty of the camera lens, and enabling the assembly process to proceed smoothly and simply.

[0049] Preferably, the above eight-element large-aperture imaging lens satisfies the relationship: 0.22 < (f8 - f7) / (f2 - f1) < 0.34; where f1 is the focal length of the first lens 11, f2 is the focal length of the second lens 12, f7 is the focal length of the seventh lens 17, and f8 is the focal length of the eighth lens 18. By controlling the focal length ratio, the optical imaging lens can have better aberration correction ability.

[0050] Preferably, the above eight-element large-aperture imaging lens satisfies the relationship: 0.65 < CT1 / (CT4 + CT5) ≤ 1.14; where CT1 is the maximum thickness of the first lens 11 on the optical axis, CT4 is the maximum thickness of the fourth lens 14 on the optical axis, and CT5 is the maximum thickness of the fifth lens 15 on the optical axis. The maximum thickness ratio of the above lenses is beneficial to reducing the lens volume and achieving the miniaturization of the lens.

[0051] Preferably, the above eight-element large-aperture imaging lens satisfies the relationship: -2.88 < f5 / f6 < -0.16; where f5 is the focal length of the fifth lens 15 and f6 is the focal length of the sixth lens 16. Satisfying the above relationship can reasonably distribute the bending power of the lens, effectively shorten the total length of the camera lens while ensuring the imaging quality.

[0052] Preferably, the above eight-element large-aperture imaging lens satisfies the relationship: 0.51 < f / f1 < 0.84; where f is the effective focal length of the eight-element large-aperture imaging lens and f1 is the focal length of the first lens 11. By controlling the ratio of the effective focal length of the entire system to the focal length of the first lens 11, the excessive optical power of the first lens 11 can be avoided, making the optical imaging lens have low sensitivity and good imaging quality, and at the same time making the optical imaging lens have a shorter optical length.

[0053] Preferably, the above eight-element large-aperture imaging lens satisfies the relationship: -4.94 < f4 / f < -3.31; where f is the effective focal length of the eight-element large-aperture imaging lens and f4 is the focal length of the fourth lens 14. By controlling the ratio of the focal length of the fourth lens 14 to the effective focal length of the entire system, the excessive optical power of the fourth lens 14 can be avoided, making the optical imaging lens have low sensitivity and good imaging quality, and at the same time making the optical imaging lens have a shorter optical length.

[0054] Preferably, the above eight-element large-aperture imaging lens satisfies the relationship: 0.08 < CT5 / TTL < 0.15; where CT5 is the maximum thickness of the fifth lens 15 on the optical axis and TTL is the distance from the object side surface of the first lens 11 near the optical axis to the imaging surface. Satisfying the above relationship is beneficial to controlling the thickness of the fifth lens 15 on the optical axis and is beneficial to reducing the sensitivity of the optical imaging lens.

[0055] Preferably, the eight-element large aperture imaging lens satisfies the relationship: f / EPD≦1.48; wherein EPD is the entrance pupil diameter, and f is the effective focal length of the eight-element large aperture imaging lens. By controlling the above ratio to expand the aperture and increase the amount of light passing, better imaging effects can be achieved.

[0056] The eight-element large aperture imaging lens of the present invention will be described in detail through the following specific embodiments with reference to the accompanying drawings.

[0057] First embodiment

[0058] Please combine Figure 2 and Figure 3 In the first embodiment, the eight-element large aperture imaging lens satisfies Table 1-1, Table 1-2 and Table 1-3.

[0059] Table 1-1 shows the basic parameters of the eight-element large aperture imaging lens of the first embodiment:

[0060]

[0061]

[0062] Table 1-2 shows the aspheric coefficients of each lens in the first embodiment:

[0063]

[0064] Table 1-3 shows the values ​​of the conditional expressions in the first embodiment:

[0065]

[0066] Second embodiment

[0067] Please combine Figures 4 to 6 The eight-lens large aperture imaging lens of this embodiment includes, from the object side to the image side, a first lens 21, a second lens 22, a third lens 23, a fourth lens 24, a fifth lens 25, a sixth lens 26, a seventh lens 27, and an eighth lens 28. In a specific implementation, a stop 20 is provided on the object side surface of the first lens 21, and a filter 29 is provided on the image side surface of the eighth lens 28.

[0068] It should be understood that the eight-element large aperture imaging lens in the second embodiment satisfies the refractive force, surface roughness, and various expressions in the first embodiment, which will not be described in detail here.

[0069] In the second embodiment, the eight-element large aperture imaging lens satisfies Table 2-1, Table 2-2, and Table 2-3.

[0070] Table 2-1 shows the basic parameters of the eight-element large aperture imaging lens of the second embodiment:

[0071]

[0072] Table 2-2 shows the aspheric coefficients of each lens in the second embodiment:

[0073]

[0074]

[0075] Table 2-3 shows the values ​​of the conditional expressions in the second embodiment:

[0076]

[0077] Third embodiment

[0078] Please combine Figures 7 to 9 The eight-lens large aperture imaging lens of this embodiment includes, from the object side to the image side, a first lens 31, a second lens 32, a third lens 33, a fourth lens 34, a fifth lens 35, a sixth lens 36, a seventh lens 37, and an eighth lens 38. In a specific implementation, a stop 30 is provided on the object side surface of the first lens 31, and a filter 39 is provided on the image side surface of the eighth lens 38.

[0079] It should be understood that the eight-element large aperture imaging lens in the third embodiment satisfies the refractive force, surface roughness, and various expressions in the first embodiment, which will not be described in detail here.

[0080] In the third embodiment, the eight-element large aperture imaging lens satisfies Table 3-1, Table 3-2, and Table 3-3.

[0081] Table 3-1 shows the basic parameters of the eight-element large aperture imaging lens of the third embodiment:

[0082]

[0083]

[0084] Table 3-2 shows the aspheric coefficients of each lens in the third embodiment:

[0085]

[0086] Table 3-3 shows the values ​​of the conditional expressions in the third embodiment:

[0087]

[0088] Fourth embodiment

[0089] Please combine Figures 10 to 12The eight-lens large aperture imaging lens of this embodiment includes, from the object side to the image side, a first lens 41, a second lens 42, a third lens 43, a fourth lens 44, a fifth lens 45, a sixth lens 46, a seventh lens 47, and an eighth lens 48. In a specific implementation, a stop 40 is provided on the object side surface of the first lens 41, and a filter 49 is provided on the image side surface of the eighth lens 48.

[0090] It should be understood that the eight-element large aperture imaging lens in the fourth embodiment satisfies the refractive force, surface roughness, and various expressions in the first embodiment, which will not be described in detail here.

[0091] In the fourth embodiment, the eight-element large aperture imaging lens satisfies Table 4-1, Table 4-2 and Table 4-3.

[0092] Table 4-1 shows the basic parameters of the eight-element large aperture imaging lens of the fourth embodiment:

[0093]

[0094]

[0095] Table 4-2 shows the aspheric coefficients of each lens in the fourth embodiment:

[0096]

[0097] Table 4-3 shows the values ​​of the conditional expressions in the fourth embodiment:

[0098]

[0099]

[0100] Fifth embodiment

[0101] Please combine Figures 13 to 15 The eight-lens large aperture imaging lens of this embodiment includes, from the object side to the image side, a first lens 51, a second lens 52, a third lens 53, a fourth lens 54, a fifth lens 55, a sixth lens 56, a seventh lens 57, and an eighth lens 58. In specific implementation, a stop 50 is provided on the object side surface of the first lens 51, and a filter 59 is provided on the image side surface of the eighth lens 58.

[0102] It should be understood that the eight-element large aperture imaging lens in the fifth embodiment satisfies the refractive force, surface roughness, and various expressions in the first embodiment, which will not be described in detail here.

[0103] In the fifth embodiment, the eight-element large aperture imaging lens satisfies Table 5-1, Table 5-2 and Table 5-3.

[0104] Table 5-1 shows the basic parameters of the eight-element large aperture imaging lens of the fifth embodiment:

[0105]

[0106] Table 5-2 shows the aspheric coefficients of each lens in the fifth embodiment:

[0107]

[0108]

[0109] Table 5-3 shows the values ​​of the conditional expressions in the fifth embodiment:

[0110]

[0111] Sixth embodiment

[0112] Please combine Figures 16 to 18 The eight-lens large aperture imaging lens of this embodiment includes, from the object side to the image side, a first lens 61, a second lens 62, a third lens 63, a fourth lens 64, a fifth lens 65, a sixth lens 66, a seventh lens 67, and an eighth lens 68. In specific implementation, a stop 60 is provided on the object side surface of the first lens 61, and a filter 69 is provided on the image side surface of the eighth lens 68.

[0113] It should be understood that the eight-element large aperture imaging lens in the sixth embodiment satisfies the refractive force, surface roughness, and various expressions in the first embodiment described above, which will not be elaborated here.

[0114] In the sixth embodiment, the eight-element large aperture imaging lens satisfies Table 6-1, Table 6-2, and Table 6-3.

[0115] Table 6-1 shows the basic parameters of the eight-element large aperture imaging lens of the sixth embodiment:

[0116]

[0117]

[0118] Table 6-2 shows the aspheric coefficients of each lens in the sixth embodiment:

[0119]

[0120] Table 6-3 shows the values ​​of the conditional expressions in the sixth embodiment:

[0121]

[0122] In order to facilitate comparison of the above six embodiments, the following table summarizes the values ​​obtained by each expression under the corresponding conditions of each embodiment:

[0123]

[0124] The eight-lens large aperture imaging lens in the above embodiment effectively shortens the overall length of the lens while ensuring high imaging quality through reasonable refractive force matching, so that the lens meets the requirements of thinness. Reasonable parameter matching between each lens makes the lens have the characteristics of large aperture and large field of view, meeting people's shooting needs in low light environment and wide angle.

[0125] In the description of the present invention, it is necessary to understand that terms such as "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc., indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention.

[0126] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features. In the description of the present invention, the meaning of "plurality" is two or more, unless otherwise clearly and specifically defined.

[0127] Although the present invention is described in conjunction with the above specific embodiments, it is obvious that those skilled in the art can make many substitutions, modifications and changes according to the above content. Therefore, all such substitutions, improvements and changes are included in the spirit and scope of the appended claims.

Claims

1. An eight-element large aperture imaging lens, characterized in that: In order from the object side to the image side, it includes: A first lens with positive refractive power, whose object-side surface is convex near the optical axis and whose image-side surface is concave near the optical axis; A second lens with negative refractive power, whose object-side surface is convex near the optical axis and whose image-side surface is concave near the optical axis; A third lens with positive refractive power, whose object-side surface is convex near the optical axis and whose image-side surface is concave near the optical axis; A fourth lens with negative refractive power, whose object-side surface is concave near the optical axis; A fifth lens with negative refractive power, whose image-side surface is concave near the optical axis; A sixth lens with positive refractive power, whose object-side surface is convex near the optical axis and whose image-side surface is concave near the optical axis; A seventh lens with positive refractive power, whose object-side surface is convex near the optical axis and whose image-side surface is concave near the optical axis; An eighth lens with negative refractive power, whose object-side surface is concave near the optical axis and whose image-side surface is concave near the optical axis; The eight-element large-aperture imaging lens satisfies the following relationship: TTL / ImgH < 0.84; where TTL is the distance from the object side surface of the first lens at the optical axis to the imaging surface, and ImgH is the length of the diagonal of the effective imaging area of the eight-element large-aperture imaging lens; The object-side surfaces and image-side surfaces of the first lens, second lens, third lens, fourth lens, fifth lens, sixth lens, seventh lens, and eighth lens are all aspherical surfaces; The eight-element large-aperture imaging lens satisfies the relationship: -3.3 < R72 / R81 < -2.25; where R72 is the radius of curvature of the image-side surface of the seventh lens, and R81 is the radius of curvature of the object-side surface of the eighth lens.

2. The eight-element large aperture imaging lens according to claim 1, characterized in that: The eight-element large-aperture imaging lens satisfies the relationship: ND2 ≥ 1.68, ND1 = ND3 = ND5 = ND6 = ND7; where ND1, ND2, ND3, ND5, ND6, and ND7 are the refractive indices of the first lens, second lens, third lens, fifth lens, sixth lens, and seventh lens, respectively.

3. The eight-element large aperture imaging lens according to claim 1, characterized in that: The eight-element large-aperture imaging lens satisfies the relationship: 0.22 ≤ T67 / CT1 < 0.26; where T67 is the distance between the sixth lens and the seventh lens on the optical axis, and CT1 is the maximum thickness of the first lens on the optical axis.

4. The eight-element large aperture imaging lens according to claim 1, characterized in that: The eight-element large-aperture imaging lens satisfies the relationship: 0.22 < (f8 - f7) / (f2 - f1) < 0.34; where f1 is the focal length of the first lens, f2 is the focal length of the second lens, f7 is the focal length of the seventh lens, and f8 is the focal length of the eighth lens.

5. The eight-element large aperture imaging lens according to claim 1, characterized in that: The eight-element large-aperture imaging lens satisfies the relationship: 0.65 < CT1 / (CT4 + CT5) ≤ 1.14; where CT1 is the maximum thickness of the first lens on the optical axis, CT4 is the maximum thickness of the fourth lens on the optical axis, and CT5 is the maximum thickness of the fifth lens on the optical axis.

6. The eight-element large aperture imaging lens according to claim 1, characterized in that: The eight - element large - aperture imaging lens satisfies the relationship: - 2.88 < f5 / f6 < - 0.16; where f5 is the focal length of the fifth lens and f6 is the focal length of the sixth lens.

7. The eight-element large aperture imaging lens according to claim 1, characterized in that: The eight - element large - aperture imaging lens satisfies the relationship: 0.51 < f / f1 < 0.84; where f is the effective focal length of the eight - element large - aperture imaging lens and f1 is the focal length of the first lens.

8. The eight-element large aperture imaging lens according to claim 1, characterized in that: The eight - element large - aperture imaging lens satisfies the relationship: - 4.94 < f4 / f < - 3.31; where f is the effective focal length of the eight - element large - aperture imaging lens and f4 is the focal length of the fourth lens.

9. The eight-element large aperture imaging lens according to claim 1, characterized in that: The eight - element large - aperture imaging lens satisfies the relationship: 0.08 < CT5 / TTL < 0.15; where CT5 is the maximum thickness of the fifth lens on the optical axis and TTL is the distance from the object - side surface of the first lens at the near - optical - axis to the imaging plane.

10. The eight-element large aperture imaging lens according to claim 1, characterized in that: The eight - element large - aperture imaging lens satisfies the relationship: f / EPD ≦ 1.48; where EPD is the entrance pupil diameter and f is the effective focal length of the eight - element large - aperture imaging lens.

Images