Optical imaging lens group

Abstract

The present application discloses an optical imaging lens group, which sequentially includes, from the object side to the image side along the optical axis: a first lens with a focal power, a second lens, a third lens, a fourth lens, a fifth lens, a sixth lens, a seventh lens, and an eighth lens. The first lens has a negative focal power; the fourth lens has a positive focal power; the eighth lens has a negative focal power; at least one of the first lens to the eighth lens has an aspherical mirror surface with non-rotational symmetry; and the maximum TV distortion TDT within the imaging range of the optical imaging lens group satisfies: |TDT| ≤ 3.5%.

Description

Technical Field

[0001] This application relates to the field of optical elements, and specifically, to an optical imaging lens group. Background Art

[0002] In recent years, with the rapid development of technologies in the fields of optics, electronics, materials, etc., various electronic products have gradually entered thousands of households and become an indispensable part of people's lives. Among them, photographic electronic products have blossomed particularly during this period. The photographic works of photographic electronic products have become an important carrier for people to record their personal lives and precious moments. An electronic product with powerful photographic functions will undoubtedly be favored by the majority of consumers.

[0003] However, in an ideal optical imaging system, traditional rotationally symmetric aspherical surfaces can well correct the aberrations in the meridional plane and sagittal plane. But for an actual optical imaging system with wide-beam imaging, as the image plane size increases, off-axis aberrations are very difficult to be corrected equally. Summary of the Invention

[0004] This application provides an optical imaging lens group, which sequentially includes, from the object side to the image side along the optical axis: a first lens with a focal power, a second lens, a third lens, a fourth lens, a fifth lens, a sixth lens, a seventh lens, and an eighth lens; the first lens has a negative focal power; the fourth lens has a positive focal power; the eighth lens has a negative focal power; at least one of the first lens to the eighth lens has a non-rotationally symmetric aspherical mirror surface; and the maximum TV distortion TDT within the imaging range of the optical imaging lens group can satisfy: |TDT| ≤ 3.5%.

[0005] In one embodiment, at least one of the object side surface of the first lens to the image side surface of the eighth lens has a rotationally symmetric aspherical mirror surface.

[0006] In one embodiment, the image height IHx in the X-axis direction of the optical imaging lens group and the image height IHy in the Y-axis direction of the optical imaging lens group can satisfy:

[0007] In one embodiment, the semi-field of view angle Semi-FOVx in the X-axis direction of the optical imaging lens group and the semi-field of view angle FOVy in the Y-axis direction of the optical imaging lens group can satisfy: tan(Semi-FOVy) / tan(Semi-FOVx) < 2.0.

[0008] In one embodiment, among the object side surface of the first lens to the image side surface of the fourth lens, the values of the effective radii of each mirror surface in the Y-axis direction of the optical imaging lens group decrease in sequence; and among the image side surface of the fourth lens to the image side surface of the eighth lens, the values of the effective radii of each mirror surface in the Y-axis direction of the optical imaging lens group increase in sequence.

[0009] In one embodiment, the maximum effective radius DT11 of the object side surface of the first lens in the Y-axis direction of the optical imaging lens group, the maximum effective radius DT42 of the image side surface of the fourth lens in the Y-axis direction of the optical imaging lens group, and the effective radius DT82 of the image side surface of the eighth lens may satisfy: 1 < (DT11 - DT42) / (DT82 - DT42) ≤ 1.2.

[0010] In one embodiment, the refractive index N2 of the second lens in the Y-axis direction of the optical imaging lens group and the refractive index N3 of the third lens in the Y-axis direction of the optical imaging lens group may satisfy: 1.6 < (N2 + N3) / 2 < 1.7.

[0011] In one embodiment, the Abbe number V2 of the second lens in the Y-axis direction of the optical imaging lens group and the Abbe number V3 of the third lens in the Y-axis direction of the optical imaging lens group may satisfy: |V2 - V3| ≤ 20.

[0012] In one embodiment, the Abbe number V6 of the sixth lens in the Y-axis direction of the optical imaging lens group, the Abbe number V7 of the seventh lens in the Y-axis direction of the optical imaging lens group, and the Abbe number V8 of the eighth lens may satisfy: 50 < (V6 + V7 + V8) / 3 < 60.

[0013] In one embodiment, the refractive index N6 of the sixth lens in the Y-axis direction of the optical imaging lens group, the refractive index N7 of the seventh lens in the Y-axis direction of the optical imaging lens group, and the refractive index N8 of the eighth lens in the Y-axis direction of the optical imaging lens group may satisfy: 1.5 < (N6 + N7 + N8) / 3 < 1.6.

[0014] In one embodiment, the effective focal length f1y of the first lens in the Y-axis direction and the total effective focal length fy of the optical imaging lens group in the Y-axis direction may satisfy: -3.0 < f1y / fy < -2.0.

[0015] In one embodiment, the effective focal length f4y of the fourth lens in the Y-axis direction and the effective focal length f6y of the sixth lens in the Y-axis direction may satisfy: 3.5 < f6y / f4y < 5.0.

[0016] In one embodiment, the effective focal length f1y of the first lens in the Y-axis direction and the effective focal length f8y of the eighth lens in the Y-axis direction may satisfy: 3.0 ≤ f1y / f8y < 4.0.

[0017] In one embodiment, the total effective focal length fx of the optical imaging lens group in the X-axis direction and the total effective focal length fy of the optical imaging lens group in the Y-axis direction may satisfy: 1.0 < fx / fy < 1.5.

[0018] The present application provides an optical imaging lens group, which sequentially includes, from the object side to the image side along the optical axis: a first lens with a focal power, a second lens, a third lens, a fourth lens, a fifth lens, a sixth lens, a seventh lens, and an eighth lens; the first lens has a negative focal power; the fourth lens has a positive focal power; the eighth lens has a negative focal power; at least one of the first lens to the eighth lens has an aspherical mirror surface with non-rotational symmetry; and the image height IHx in the X-axis direction of the optical imaging lens group and the image height IHy in the Y-axis direction of the optical imaging lens group can satisfy:

[0019] The present application uses eight lenses. By reasonably distributing the focal power, surface shape, central thickness of each lens, and the on-axis spacing between each lens, etc., the above optical imaging system has at least one beneficial effect such as small distortion, low aberration, and good imaging quality. Description of the Drawings

[0020] By reading the detailed description of the non-limiting embodiments with reference to the following drawings, other features, objectives, and advantages of the present application will become more obvious:

[0021] Figure 1 Fig. shows a schematic structural diagram of the optical imaging lens group according to Embodiment 1 of the present application;

[0022] Figure 2 Fig. shows the situation of the RMS spot diameter of the optical imaging lens group according to Embodiment 1 of the present application in the first quadrant;

[0023] Figure 3 Fig. shows the TV distortion diagram of the optical imaging lens group according to Embodiment 1 of the present application;

[0024] Figure 4 Fig. shows a schematic structural diagram of the optical imaging lens group according to Embodiment 2 of the present application;

[0025] Figure 5 Fig. shows the situation of the RMS spot diameter of the optical imaging lens group according to Embodiment 2 of the present application in the first quadrant; and

[0026] Figure 6 Fig. shows the TV distortion diagram of the optical imaging lens group according to Embodiment 2 of the present application. Detailed Embodiments

[0027] To better understand the present application, various aspects of the present application will be described in more detail with reference to the accompanying drawings. It should be understood that these detailed descriptions are only descriptions of exemplary embodiments of the present application and do not limit the scope of the present application in any way. Throughout the specification, the same reference numerals refer to the same elements. The expression "and / or" includes any and all combinations of one or more of the associated listed items.

[0028] It should be noted that in this specification, the expressions such as first, second, third, etc. are only used to distinguish one feature from another feature and do not represent any limitation on the feature. Therefore, without departing from the teachings of the present application, the first lens discussed below may also be referred to as the second lens or the third lens.

[0029] In the drawings, for the sake of clarity, the thickness, dimensions and shape of the lens have been slightly exaggerated. Specifically, the spherical or aspherical shapes shown in the drawings are shown by way of example. That is, the spherical or aspherical shapes are not limited to the spherical or aspherical shapes shown in the drawings. The drawings are only examples and are not drawn to an exact scale.

[0030] In this document, the paraxial region refers to the region near the optical axis. If the lens surface is convex and the position of the convex surface is not defined, it means that the lens surface is convex at least in the paraxial region; if the lens surface is concave and the position of the concave surface is not defined, it means that the lens surface is concave at least in the paraxial region. The surface of each lens closest to the object to be photographed is called the object side surface of the lens, and the surface of each lens closest to the imaging surface is called the image side surface of the lens.

[0031] In this document, we define the direction parallel to the optical axis as the Z-axis direction, the direction perpendicular to the Z-axis and located in the meridian plane as the Y-axis direction, and the direction perpendicular to the Z-axis and located in the sagittal plane as the X-axis direction. Unless otherwise specified, all parameter symbols in this document other than those related to the field of view (for example, the radius of curvature, etc.) represent the characteristic parameter values in the Y-axis direction of the optical imaging lens group. For example, without special instructions, fx represents the radius of curvature in the X-axis direction of the optical imaging lens group, and fy represents the radius of curvature in the Y-axis direction of the optical imaging lens group.

[0032] It should also be understood that the terms "comprising", "comprises", "having", "includes" and / or "including", when used in this specification, denote the presence of the stated features, elements and / or components, but do not preclude the presence or addition of one or more other features, elements, components and / or combinations thereof. Further, when an expression such as "at least one of..." appears after a list of listed features, it modifies the entire list of listed features rather than individual elements in the list. Further, when describing embodiments of the present application, the use of "may" means "one or more embodiments of the present application". Also, the term "exemplary" is intended to refer to an example or illustration.

[0033] Unless otherwise defined, all terms (including 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. It should also be understood that terms (such as those defined in a common dictionary) should be interpreted as having a meaning consistent with their meaning in the context of the relevant art and will not be interpreted in an idealized or overly formal sense unless expressly so defined herein.

[0034] It should be noted that, without conflict, the embodiments and features in the embodiments of the present application may be combined with each other. The present application will be described in detail below with reference to the drawings and in combination with embodiments.

[0035] The features, principles and other aspects of the present application will be described in detail below.

[0036] The optical imaging lens group according to an exemplary embodiment of the present application may include eight lenses having optical power, namely 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. These eight lenses are arranged in sequence along the optical axis from the object side to the image side. There may be a spacing distance between any two adjacent lenses among the first lens to the eighth lens.

[0037] In an exemplary embodiment, the first lens may have negative optical power; the second lens may have positive optical power or negative optical power; the third lens may have positive optical power or negative optical power; the fourth lens may have positive optical power; the fifth lens may have positive optical power or negative optical power; the sixth lens may have positive optical power or negative optical power; the seventh lens may have positive optical power or negative optical power; the eighth lens may have negative optical power.

[0038] In an exemplary embodiment, the first lens has a negative optical power and diverges light rays, which is beneficial to increasing the field of view angle of the system and enlarging the object-taking space of the system; by mounting a fourth lens with a positive optical power and integrating the second and third lenses, the field curvature of the system can be balanced, the chromatic spherical aberration of the system can be optimized, and at the same time, the light rays can be smoothly transitioned; by mounting the fifth, sixth, and seventh lenses and an eighth lens with a negative optical power, the overall lens structure group can be in a double-Gauss structure, which can comprehensively correct the aberration of the system while ensuring the smooth and stable propagation of light rays.

[0039] In an exemplary embodiment, at least one of the first lens to the eighth lens may have an aspherical surface with non-rotational symmetry. At least one of the first lens to the eighth lens having an aspherical surface structure with non-rotational symmetry can improve the ability of the system to optimize degrees of freedom, which is beneficial to reasonably distributing the optical power in the X-axis direction and the Y-axis direction and correcting the distortion of the system.

[0040] In an exemplary embodiment, the optical imaging lens group according to the present application may satisfy: |TDT| ≤ 3.5%, where TDT is the maximum TV distortion within the imaging range of the optical imaging lens group. Satisfying |TDT| ≤ 3.5% can make the TV distortion smaller than the range where the human eye can distinguish images, which is of great significance for the design of the optical system.

[0041] In an exemplary embodiment, the optical imaging lens group according to the present application may satisfy: where IHx is the image height in the X-axis direction of the optical imaging lens group, and IHy is the image height in the Y-axis direction of the optical imaging lens group. More specifically, IHx and IHy may further satisfy: Satisfying can control the image plane size of the system within a certain range, and further make the structural size of the system have a certain ratio, so as to be easily installed in the lens and facilitate cooperation with the imaging chip.

[0042] In an exemplary embodiment, the optical imaging lens group according to the present application may satisfy: tan(Semi - FOVy) / tan(Semi - FOVx) < 2.0, where Semi - FOVx is the half - field - of - view angle in the X - axis direction of the optical imaging lens group, and FOVy is the half - field - of - view angle in the Y - axis direction of the optical imaging lens group. More specifically, Semi - FOVy and Semi - FOVx may further satisfy: tan(Semi - FOVy) / tan(Semi - FOVx) < 1.8. Satisfying tan(Semi - FOVy) / tan(Semi - FOVx) < 2.0 is beneficial for distributing the optical power in the X - axis and Y - axis directions of the system. By reasonably distributing the optical power of the system, it is beneficial to correct the distortion of the system and make the field - of - view angles in the X - axis and Y - axis directions form a certain compression ratio.

[0043] In an exemplary embodiment, among the object side surface of the first lens to the image side surface of the fourth lens, the values of the effective radii of each mirror surface in the Y - axis direction of the optical imaging lens group decrease in sequence; and among the image side surface of the fourth lens to the image side surface of the eighth lens, the values of the effective radii of each mirror surface in the Y - axis direction of the optical imaging lens group increase in sequence. This is beneficial for the optical imaging lens group to have a symmetric double - Gauss structure, so as to facilitate correcting the aberration of the system.

[0044] In an exemplary embodiment, the optical imaging lens group according to the present application may satisfy: 1 < (DT11 - DT42) / (DT82 - DT42) ≤ 1.2, where DT11 is the maximum effective radius of the object side surface of the first lens in the Y - axis direction of the optical imaging lens group, DT42 is the maximum effective radius of the image side surface of the fourth lens in the Y - axis direction of the optical imaging lens group, and DT82 is the effective radius of the image side surface of the eighth lens. Satisfying 1 < (DT11 - DT42) / (DT82 - DT42) ≤ 1.2 can control the proportional size of the overall optical structure of the system within a certain range and carry other lenses for imaging. Determining the overall optical structure shape of the system is beneficial for optimizing the process performance.

[0045] In an exemplary embodiment, the optical imaging lens group according to the present application may satisfy: 1.6 < (N2 + N3) / 2 < 1.7, where N2 is the refractive index of the second lens in the Y - axis direction of the optical imaging lens group, and N3 is the refractive index of the third lens in the Y - axis direction of the optical imaging lens group. Satisfying 1.6 < (N2 + N3) / 2 < 1.7 is beneficial for ensuring a smooth transition of light rays. On the basis of a certain structure of the second lens and the third lens, by constraining the refractive indices of the second lens and the third lens to distribute the optical power, it is beneficial to correct the spherical aberration of the system.

[0046] In an exemplary embodiment, the optical imaging lens group according to the present application can satisfy: |V2 - V3| ≤ 20, where V2 is the Abbe number of the second lens in the Y-axis direction of the optical imaging lens group, and V3 is the Abbe number of the third lens in the Y-axis direction of the optical imaging lens group. Satisfying |V2 - V3| ≤ 20 is beneficial to eliminating chromatic aberration of the system.

[0047] In an exemplary embodiment, the optical imaging lens group according to the present application can satisfy: 50 < (V6 + V7 + V8) / 3 < 60, where V6 is the Abbe number of the sixth lens in the Y-axis direction of the optical imaging lens group, V7 is the Abbe number of the seventh lens in the Y-axis direction of the optical imaging lens group, and V8 is the Abbe number of the eighth lens in the Y-axis direction of the optical imaging lens group. More specifically, V6, V7, and V8 can further satisfy: 54.6 < (V6 + V7 + V8) / 3 < 58.1. Satisfying 50 < (V6 + V7 + V8) / 3 < 60 can correct chromatic aberration of the system.

[0048] In an exemplary embodiment, the optical imaging lens group according to the present application can satisfy: 1.5 < (N6 + N7 + N8) / 3 < 1.6, where N6 is the refractive index of the sixth lens in the Y-axis direction of the optical imaging lens group, N7 is the refractive index of the seventh lens in the Y-axis direction of the optical imaging lens group, and N8 is the refractive index of the eighth lens in the Y-axis direction of the optical imaging lens group. Satisfying 1.5 < (N6 + N7 + N8) / 3 < 1.6 can reasonably distribute the corresponding optical power and is beneficial to correcting field curvature of the system.

[0049] In an exemplary embodiment, the optical imaging lens group according to the present application can satisfy: -3.0 < f1y / fy < -2.0, where f1y is the effective focal length of the first lens in the Y-axis direction, and fy is the total effective focal length of the optical imaging lens group in the Y-axis direction. More specifically, f1y and fy can further satisfy: -2.8 < f1y / fy < -2.5. Satisfying -3.0 < f1y / fy < -2.0 can change the degree of non-rotation symmetry of the aspherical surface of the first lens, which is beneficial to correcting the distortion in the Y-axis direction that is not fully corrected after the combined imaging of other lenses. In an exemplary embodiment, the optical imaging lens group according to the present application can satisfy: 3.5 < f6y / f4y < 5.0, where f4y is the effective focal length of the fourth lens in the Y-axis direction, and f6y is the effective focal length of the sixth lens in the Y-axis direction. More specifically, f6y and f4y can further satisfy: 3.8 < f6y / f4y < 4.2. Satisfying 3.5 < f6y / f4y < 5.0 can distribute the optical power in the Y-axis direction by optimizing the degree of non-rotation symmetry of the aspherical surfaces of the fourth lens and the sixth lens, thereby reducing the imaging difference between the actual imaging point and the ideal imaging point in the Y-axis direction, and further correcting the aberration in the Y-axis direction.

[0050] In an exemplary embodiment, the optical imaging lens group according to the present application can satisfy: 3.0 ≤ f1y / f8y < 4.0, where f1y is the effective focal length of the first lens in the Y-axis direction, and f8y is the effective focal length of the eighth lens in the Y-axis direction. More specifically, f1y and f8y can further satisfy: 3.0 ≤ f1y / f8y < 3.7. Satisfying 3.0 ≤ f1y / f8y < 4.0 can correct the aberration in the Y-axis direction of the system, and at the same time can make the first lens and the eighth lens have a certain degree of non-rotational symmetry.

[0051] In an exemplary embodiment, the optical imaging lens group according to the present application can satisfy: 1.0 < fx / fy < 1.5, where fx is the total effective focal length of the optical imaging lens group in the X-axis direction, and fy is the total effective focal length of the optical imaging lens group in the Y-axis direction. More specifically, fx and fy can further satisfy: 1.0 < fx / fy < 1.5. Satisfying 1.0 < fx / fy < 1.5 can achieve the ratio difference between the X-axis direction and the Y-axis direction in a specific proportion of the imaging screen, meet the special requirements for stretching or compressing the screen, and achieve a non-rotationally symmetric image quality state.

[0052] In an exemplary embodiment, the optical imaging lens group according to the present application further includes a diaphragm disposed between the fourth lens and the fifth lens. Optionally, the above optical imaging lens group may further include a filter for correcting color deviation and / or a protective glass for protecting the photosensitive element located on the imaging surface.

[0053] The optical imaging lens group according to the above embodiment of the present application can adopt multiple lenses, such as the eight lenses described above. By reasonably distributing the optical power, surface shape, central thickness of each lens, and the on-axis distance between each lens, etc., the volume of the optical imaging lens group can be effectively reduced and the processability of the optical imaging lens group can be improved, making the optical imaging lens group more conducive to production and processing and applicable to portable electronic products. The optical imaging lens group configured as above can have characteristics such as small distortion and good imaging quality.

[0054] In an embodiment of the present application, at least one of the mirror surfaces of each lens is an aspherical mirror surface, that is, at least one of the object-side surface of the first lens to the image-side surface of the eighth lens is an aspherical mirror surface. The characteristic of an aspherical lens is that the curvature changes continuously from the center of the lens to the periphery of the lens. Different from a spherical lens with a constant curvature from the center of the lens to the periphery, an aspherical lens has better curvature radius characteristics and has the advantages of improving distortion aberration and astigmatism aberration. After using an aspherical lens, it is possible to eliminate as much as possible the aberration that appears during imaging, thereby improving the imaging quality. Optionally, at least one of the object-side surface and the image-side surface of each of the first lens, the second lens, the third lens, the fourth lens, the fifth lens, the sixth lens, the seventh lens, and the eighth lens is an aspherical mirror surface. Optionally, both the object-side surface and the image-side surface of each of the first lens, the second lens, the third lens, the fourth lens, the fifth lens, the sixth lens, the seventh lens, and the eighth lens are aspherical mirror surfaces.

[0055] However, those skilled in the art should understand that without departing from the technical solutions claimed in the present application, the number of lenses constituting the optical imaging lens group can be changed to obtain the various results and advantages described in this specification. For example, although eight lenses are described as an example in the embodiment, the optical imaging lens group is not limited to including eight lenses. If necessary, the optical imaging lens group may also include other numbers of lenses.

[0056] The following further describes specific embodiments of the optical imaging lens group applicable to the above embodiments with reference to the accompanying drawings.

[0057] Example 1

[0058] The following refers to Figures 1 to 3 Describe the optical imaging lens group according to Embodiment 1 of the present application. Figure 1 The structural schematic diagram of the optical imaging lens group according to Embodiment 1 of the present application is shown.

[0059] As Figure 1 shown, the optical imaging lens group sequentially includes, from the object side to the image side: a first lens E1, a second lens E2, a third lens E3, a fourth lens E4, a fifth lens E5, a sixth lens E6, a seventh lens E7, an eighth lens E8, a filter E9, and an imaging surface S19.

[0060] The first lens E1 has a negative focal power, with its object side S1 being convex and its image side S2 being concave. The second lens E2 has a positive focal power, with its object side S3 being concave and its image side S4 being convex. The third lens E3 has a positive focal power, with its object side S5 being concave and its image side S6 being convex. The fourth lens E4 has a positive focal power, with its object side S7 being convex and its image side S8 being convex. The fifth lens E5 has a negative focal power, with its object side S9 being convex and its image side S10 being concave. The sixth lens E6 has a positive focal power, with its object side S11 being convex and its image side S12 being convex. The seventh lens E7 has a positive focal power, with its object side S13 being concave and its image side S14 being convex. The eighth lens E8 has a negative focal power, with its object side S15 being concave and its image side S16 being convex. The filter E9 has an object side S17 and an image side S18. Light from the object sequentially passes through the surfaces S1 to S18 and finally forms an image on the imaging surface S19.

[0061] Table 1 shows the basic parameter table of the optical imaging lens group of Example 1. Among them, the units of the radius of curvature Y, the radius of curvature X, the thickness / distance, and the focal length Y are all millimeters (mm).

[0062]

[0063] Table 1

[0064] It should be understood that the "radius of curvature X" and "conic coefficient X" without special markings (blank spaces) in the above table are consistent with the corresponding "radius of curvature Y" and "conic coefficient Y" values. The same is true for the following examples.

[0065] In this example, the total effective focal length fx in the X-axis direction of the optical imaging lens group is 3.95 mm, the total effective focal length fy in the Y-axis direction of the optical imaging lens group is 3.12 mm, and the distance TTL from the object side S1 of the first lens E1 to the imaging surface S19 of the optical imaging lens group on the optical axis is 8.06 mm.

[0066] In Example 1, the object side and the image side of any one of the fourth lens E4 to the eighth lens E8 are rotationally symmetric aspherical surfaces. The surface profile x of each aspherical lens can be defined by, but not limited to, the following aspherical formula:

[0067]

[0068] Wherein, x is the sagitta, the distance from the vertex of the aspheric surface, when the aspheric surface is at a position with a height of h along the optical axis direction; c is the paraxial curvature of the aspheric surface, c = 1 / R (i.e., the paraxial curvature c is the reciprocal of the radius of curvature R in Table 1 above); k is the conic constant; Ai is the correction coefficient of the i-th order of the aspheric surface. Table 2 below gives the higher-order coefficients A4, A6, A8, A 10 、A 12 、A 14 、A 16 、A 18 and A 20 .

[0069] Face number A4 A6 A8 A10 A12 A14 A16 A18 A20 S7 3.7499E-01 -1.0735E-01 -1.3819E-02 4.4854E-03 1.3337E-02 -6.0379E-03 3.5588E-04 0.0000E+00 0.0000E+00 S8 -3.5171E-03 -1.6515E-02 -4.9454E-03 1.0485E-04 -1.4734E-02 -5.2319E-04 3.6646E-03 0.0000E+00 0.0000E+00 S9 7.5192E-02 6.7043E-05 -7.3903E-03 6.3693E-03 -6.1610E-03 -1.1517E-03 3.2592E-03 0.0000E+00 0.0000E+00 S10 -3.4855E-02 1.5745E-02 -8.6938E-03 9.2461E-03 -5.1079E-03 2.0956E-03 -3.9812E-04 0.0000E+00 0.0000E+00 S11 -2.1896E-02 5.0051E-03 1.0048E-02 3.8299E-04 -1.7520E-03 -2.2856E-04 7.4558E-04 0.0000E+00 0.0000E+00 S12 1.2949E-01 -1.7775E-02 1.9866E-02 -1.0396E-03 -7.2364E-03 6.4046E-03 -1.4953E-03 0.0000E+00 0.0000E+00 S13 2.0334E-01 -1.2798E-02 -4.3372E-02 6.0400E-02 -1.1218E-02 -3.1129E-03 7.6038E-04 0.0000E+00 0.0000E+00 S14 -4.4638E-01 -2.8210E-02 5.2939E-02 4.7871E-03 -6.8127E-03 -2.5832E-04 8.6514E-04 7.0743E-05 -2.9254E-05 S15 -8.2922E-01 -3.0767E-01 -1.0654E-01 -3.9401E-02 -1.5922E-02 7.1549E-03 8.3966E-03 6.6668E-03 8.9772E-03 S16 -3.4215E-01 -2.9675E-02 4.0182E-03 1.4430E-03 0.0000E+00 0.0000E+00 0.0000E+00 0.0000E+00 0.0000E+00

[0070] Table 2

[0071] It can also be seen from Table 1 that the object side and the image side of any one of the first lens E1 to the third lens E3 are both aspheric surfaces that are non-rotationally symmetric (i.e., AAS surfaces). The surface profile of the non-rotationally symmetric aspheric surface can be defined by, but not limited to, the following non-rotationally symmetric aspheric surface formula:

[0072]

[0073] Wherein, z is the sagitta of the surface parallel to the Z-axis direction; CUX and CUY are the curvatures of the surface vertex in the X and Y-axis directions respectively (curvature is the reciprocal of the radius of curvature); KX and KY are the conic constants in the X and Y-axis directions respectively; AiX and AiY are the correction coefficients of the i-th order in the rotationally symmetric component of the aspheric surface. Table 3-1 and Table 3-2 below give the 4th, 6th, 8th, 10th, 12th, 14th, 16th, 18th, 20th order coefficients of the rotationally symmetric component AY of the non-rotationally symmetric aspheric surfaces S1 - S6 that can be used in Example 1; and the 4th, 6th, 8th, 10th, 12th, 14th, 16th, 18th, 20th order coefficients of the rotationally symmetric component AX.

[0074]

[0075]

[0076] Table 3-1

[0077] Face number A4X A6X A8X A10X A12X A14X A16X A18X A20X S1 1.9378E-03 -3.9999E-04 2.7199E-05 4.3067E-06 -7.2504E-07 0.0000E+00 0.0000E+00 0.0000E+00 0.0000E+00 S2 2.4933E-03 -5.4417E-04 -6.7545E-07 1.9663E-05 -2.4537E-06 0.0000E+00 0.0000E+00 0.0000E+00 0.0000E+00 S3 0.0000E+00 0.0000E+00 0.0000E+00 0.0000E+00 0.0000E+00 0.0000E+00 0.0000E+00 0.0000E+00 0.0000E+00 S4 0.0000E+00 0.0000E+00 0.0000E+00 0.0000E+00 0.0000E+00 0.0000E+00 0.0000E+00 0.0000E+00 0.0000E+00 S5 0.0000E+00 0.0000E+00 0.0000E+00 0.0000E+00 0.0000E+00 0.0000E+00 0.0000E+00 0.0000E+00 0.0000E+00 S6 0.0000E+00 0.0000E+00 0.0000E+00 0.0000E+00 0.0000E+00 0.0000E+00 0.0000E+00 0.0000E+00 0.0000E+00

[0078] Table 3-2

[0079] Figure 2 Shows the size of the RMS spot diameter of the optical imaging lens group in Example 1 at different image height positions in the first quadrant. Figure 2Shows the relationship between the RMS spot diameter and the true ray height. Figure 2 Among them, both the X true ray height and the Y true ray height are in millimeters (mm). The minimum RMS spot diameter is 0.0018706 mm, the maximum RMS spot diameter is 0.0037517 mm, the average value of the RMS spot diameter is 0.0027628 mm, and the standard deviation of the RMS spot diameter is 0.00038407 mm. Figure 3 Shows the TV distortion diagram of the optical imaging lens group of Embodiment 1, which represents the distortion difference between the actual rays and the paraxial rays in the vertical region and the horizontal region. Among them, the maximum TV distortion in the horizontal region is 3.4532664%, and the maximum TV distortion in the vertical region is 0.64313870%. According to Figure 2 And Figure 3 It can be known that the optical imaging lens group given in Embodiment 1 can achieve good imaging quality.

[0080] Example 2

[0081] The following refers to Figures 4 to 6 Describe the optical imaging lens group according to Embodiment 2 of the present application. In this embodiment and for the sake of brevity, some descriptions similar to those in Embodiment 1 will be omitted. Figure 4 Shows a schematic structural diagram of the optical imaging lens group according to Embodiment 2 of the present application.

[0082] As Figure 4 Shown, the first lens E1, the second lens E2, the third lens E3, the fourth lens E4, the fifth lens E5, the sixth lens E6, the seventh lens E7, the eighth lens E8, the filter E9 and the imaging surface S19.

[0083] The first lens E1 has a negative optical power. Its object side S1 is convex, and its image side S2 is concave. The second lens E2 has a positive optical power. Its object side S3 is concave, and its image side S4 is convex. The third lens E3 has a positive optical power. Its object side S5 is concave, and its image side S6 is convex. The fourth lens E4 has a positive optical power. Its object side S7 is convex, and its image side S8 is convex. The fifth lens E5 has a negative optical power. Its object side S9 is convex, and its image side S10 is concave. The sixth lens E6 has a positive optical power. Its object side S11 is convex, and its image side S12 is convex. The seventh lens E7 has a positive optical power. Its object side S13 is concave, and its image side S14 is convex. The eighth lens E8 has a negative optical power. Its object side S15 is concave, and its image side S16 is convex. The filter E9 has an object side S17 and an image side S18. The light from the object sequentially passes through the surfaces S1 to S18 and finally forms an image on the imaging surface S19.

[0084] In this example, the total effective focal length fx in the X-axis direction of the optical imaging lens group is 3.94 mm, the total effective focal length fy in the Y-axis direction of the optical imaging lens group is 3.00 mm, and the distance TTL on the optical axis from the object side surface S1 of the first lens E1 to the imaging surface S19 of the optical imaging lens group is 8.06 mm.

[0085] Table 4 shows the basic parameter table of the optical imaging lens group of Example 2. Among them, the units of the radius of curvature Y, the radius of curvature X, the thickness / distance, and the focal length Y are all millimeters (mm). Table 5 gives the high-order term coefficients of the aspherical surfaces that can be used for each rotationally symmetric aspherical mirror surface in Example 2. Among them, each rotationally symmetric aspherical surface type can be defined by formula (1) given in the above Example 1. Tables 6-1 and 6-2 respectively give the rotationally symmetric components and the high-order coefficients of the non-rotationally symmetric components of the non-rotationally symmetric aspherical surfaces that can be used in Example 2. Among them, the non-rotationally symmetric aspherical surface type can be defined by formula (2) given in the above Example 1.

[0086]

[0087] Table 4

[0088] Face number A4 A6 A8 A10 A12 A14 A16 A18 A20 S7 3.7487E-01 -1.0753E-01 -1.4102E-02 4.3097E-03 1.3354E-02 -5.8745E-03 3.3337E-04 0.0000E+00 0.0000E+00 S8 -4.1268E-03 -1.7029E-02 -5.7894E-03 -7.2983E-04 -1.5213E-02 -5.2163E-04 3.7521E-03 0.0000E+00 0.0000E+00 S9 7.4965E-02 4.3408E-05 -7.3389E-03 6.3834E-03 -6.2436E-03 -1.2720E-03 3.3075E-03 0.0000E+00 0.0000E+00 S10 -3.4401E-02 1.5932E-02 -8.5949E-03 9.3664E-03 -4.9883E-03 1.9910E-03 -3.3825E-04 0.0000E+00 0.0000E+00 S11 -2.0749E-02 5.2564E-03 1.0073E-02 3.0080E-04 -1.6678E-03 1.1982E-04 5.3049E-04 0.0000E+00 0.0000E+00 S12 1.3118E-01 -1.6774E-02 2.0717E-02 -5.5444E-04 -7.0103E-03 5.8986E-03 -1.3534E-03 0.0000E+00 0.0000E+00 S13 1.9478E-01 -1.4418E-02 -4.0857E-02 6.1619E-02 -1.2459E-02 -2.6767E-03 6.8477E-04 0.0000E+00 0.0000E+00 S14 -4.4358E-01 -2.7162E-02 5.1231E-02 4.6566E-03 -6.7877E-03 -2.8938E-04 8.8063E-04 7.3405E-05 -3.1157E-05 S15 -6.8444E-01 -2.3529E-01 -1.0084E-01 -3.2573E-02 -6.3053E-03 8.4157E-03 6.9194E-03 9.4418E-04 1.1338E-02 S16 3.7072E-01 2.2937E-02 -3.7010E-03 4.4320E-04 -1.7677E-04 1.6630E-05 -2.1581E-06 2.6918E-07 0.0000E+00

[0089] Table 5

[0090] Face number A4Y A6Y A8Y A10Y A12Y A14Y A16Y A18Y A20Y S1 1.3600E-03 1.7632E-04 1.5900E-05 8.1273E-08 -1.6894E-07 -1.6358E-08 5.2428E-09 0.0000E+00 0.0000E+00 S2 1.1234E-03 1.0177E-03 5.9299E-05 4.2664E-06 2.0696E-06 4.5155E-07 -1.5037E-07 0.0000E+00 0.0000E+00 S3 3.7899E-04 4.1575E-05 -1.6678E-05 -7.7658E-07 1.1573E-06 3.6165E-07 -1.4582E-07 0.0000E+00 0.0000E+00 S4 3.2141E-04 8.6195E-04 1.4794E-04 1.2365E-05 2.1385E-07 7.1853E-07 1.2658E-06 0.0000E+00 0.0000E+00 S5 1.9765E-02 7.5986E-03 4.4465E-03 -4.5521E-04 4.6741E-04 4.1128E-04 -2.2487E-04 0.0000E+00 0.0000E+00 S6 4.0852E-03 8.1829E-03 6.1711E-03 4.5349E-03 -4.1290E-03 -9.2514E-04 2.1563E-03 0.0000E+00 0.0000E+00

[0091] Table 6-1

[0092] Face number A4X A6X A8X A10X A12X A14X A16X A18X A20X S1 1.7810E-03 -4.0210E-04 2.6953E-05 4.5549E-06 -6.3359E-07 0.0000E+00 0.0000E+00 0.0000E+00 0.0000E+00 S2 2.2866E-03 -5.4407E-04 2.4236E-06 1.9997E-05 -2.3478E-06 0.0000E+00 0.0000E+00 0.0000E+00 0.0000E+00 S3 0.0000E+00 0.0000E+00 0.0000E+00 0.0000E+00 0.0000E+00 0.0000E+00 0.0000E+00 0.0000E+00 0.0000E+00 S4 0.0000E+00 0.0000E+00 0.0000E+00 0.0000E+00 0.0000E+00 0.0000E+00 0.0000E+00 0.0000E+00 0.0000E+00 S5 0.0000E+00 0.0000E+00 0.0000E+00 0.0000E+00 0.0000E+00 0.0000E+00 0.0000E+00 0.0000E+00 0.0000E+00 S6 0.0000E+00 0.0000E+00 0.0000E+00 0.0000E+00 0.0000E+00 0.0000E+00 0.0000E+00 0.0000E+00 0.0000E+00

[0093] Table 6-2

[0094] Figure 5 Shows the size of the RMS spot diameter of the optical imaging lens group of Example 2 at different image height positions in the first quadrant. Figure 5 Shows the relationship between the RMS spot diameter and the true ray image height. Figure 5 Among them, both the X true ray height and the Y true ray height are in millimeters (mm). The minimum RMS spot diameter is 0.0015864 mm, the maximum RMS spot diameter is 0.0034325 mm, the mean value of the RMS spot diameter is 0.0025729 mm, and the standard deviation of the RMS spot diameter is 0.00043105 mm. Figure 6 Shows the TV distortion diagram of the optical imaging lens group of Example 2, which represents the distortion difference between the actual rays and the paraxial rays in the vertical region and the horizontal region. Among them, the maximum TV distortion in the horizontal region is 3.0114838%, and the maximum TV distortion in the vertical region is 0.50480041%. According to Figure 5 andFigure 6 It can be seen that the optical imaging lens group given in Embodiment 2 can achieve good imaging quality.

[0095] In summary, Embodiment 1 to Embodiment 2 respectively satisfy the relationships shown in Table 7.

[0096]

[0097] Table 7

[0098] This application also provides an imaging device, and its electronic photosensitive element can be a charge-coupled device (CCD) or a complementary metal-oxide-semiconductor element (CMOS). The imaging device can be an independent imaging device such as a digital camera, or an imaging module integrated on a mobile electronic device such as a mobile phone. The imaging device is equipped with the optical imaging lens group described above.

[0099] The above description is only the preferred embodiments of this application and the description of the applied technical principles. Those skilled in the art should understand that the scope of the invention involved in this application is not limited to the technical solutions formed by the specific combination of the above technical features, and should also cover other technical solutions formed by any combination of the above technical features or their equivalent features without departing from the inventive concept. For example, the technical solutions formed by mutually replacing the above features with the (but not limited to) technical features with similar functions disclosed in this application.

Claims

1. An optical imaging lens group, sequentially including from the object side to the image side along the optical axis: 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 having optical powers; characterized in that, The first lens has a negative optical power, its object side is convex, and its image side is concave; The second lens has a positive optical power, its object side is concave, and its image side is convex; The third lens has a positive optical power, its object side is concave, and its image side is convex; The fourth lens has a positive optical power, its object side is convex, and its image side is convex; The fifth lens has a negative optical power, its object side is convex, and its image side is concave; The sixth lens has a positive optical power, its object side is convex, and its image side is convex; The seventh lens has a positive optical power, its object side is concave, and its image side is convex; The eighth lens has a negative optical power, its object side is concave, and its image side is convex; At least one of the first lens to the eighth lens has an aspherical mirror surface with non-rotational symmetry; The number of lenses with optical powers in the optical imaging lens group is eight; and The image height IHx in the X-axis direction of the optical imaging lens group and the image height IHy in the Y-axis direction of the optical imaging lens group satisfy: The effective focal length f1y of the first lens in the Y-axis direction and the effective focal length f8y of the eighth lens in the Y-axis direction satisfy: 3.07 ≤ f1y / f8y ≤ 3.

62.

2. The optical imaging lens group according to claim 1, wherein The semi-field angle Semi-FOVx in the X-axis direction of the optical imaging lens group and the semi-field angle FOVy in the Y-axis direction of the optical imaging lens group satisfy: 1.74 ≤ tan(Semi-FOVy) / tan(Semi-FOVx) < 1.

8.

3. The optical imaging lens group according to claim 1 or 2, characterized in that, Among the object side of the first lens to the image side of the fourth lens, the values of the effective radii of each mirror surface in the Y-axis direction of the optical imaging lens group decrease in sequence; and Among the image side of the fourth lens to the image side of the eighth lens, the values of the effective radii of each mirror surface in the Y-axis direction of the optical imaging lens group increase in sequence.

4. The optical imaging lens group according to claim 1 or 2, characterized in that, The maximum effective radius DT11 of the object side of the first lens in the Y-axis direction of the optical imaging lens group, the maximum effective radius DT42 of the image side of the fourth lens in the Y-axis direction of the optical imaging lens group, and the effective radius DT82 of the image side of the eighth lens satisfy: 1.11 ≤ (DT11 - DT42) / (DT82 - DT42) ≤ 1.

13.

5. The optical imaging lens group according to claim 1 or 2, characterized in that, The refractive index N2 of the second lens in the Y-axis direction of the optical imaging lens group and the refractive index N3 of the third lens in the Y-axis direction of the optical imaging lens group satisfy: 1.65 ≤ (N2 + N3) / 2 < 1.

7.

6. The optical imaging lens group according to claim 1 or 2, characterized in that, The Abbe number V2 of the second lens in the Y-axis direction of the optical imaging lens group and the Abbe number V3 of the third lens in the Y-axis direction of the optical imaging lens group satisfy: 16.57 ≤ |V2 - V3| ≤ 19.

06.

7. The optical imaging lens group according to claim 6, characterized in that, The Abbe number V6 of the sixth lens in the Y-axis direction of the optical imaging lens group, the Abbe number V7 of the seventh lens in the Y-axis direction of the optical imaging lens group, and the Abbe number V8 of the eighth lens satisfy: 54.73 ≤ (V6 + V7 + V8) / 3 ≤ 58.

01.

8. The optical imaging lens group according to claim 7, characterized in that, The refractive index N6 of the sixth lens in the Y-axis direction of the optical imaging lens group, the refractive index N7 of the seventh lens in the Y-axis direction of the optical imaging lens group, and the refractive index N8 of the eighth lens in the Y-axis direction of the optical imaging lens group satisfy: 1.5 < (N6 + N7 + N8) / 3 < 1.

6.

9. The optical imaging lens group according to claim 1, characterized in that, The effective focal length f1y of the first lens in the Y-axis direction and the total effective focal length fy of the optical imaging lens group in the Y-axis direction satisfy: -2.69 ≤ f1y / fy ≤ -2.

61.

10. The optical imaging lens group according to claim 9, wherein, The effective focal length f4y of the fourth lens in the Y-axis direction and the effective focal length f6y of the sixth lens in the Y-axis direction satisfy: 3.90 ≤ f6y / f4y ≤ 4.

13.

11. The optical imaging lens group according to claim 1, wherein, The total effective focal length fx of the optical imaging lens group in the X-axis direction and the total effective focal length fy of the optical imaging lens group in the Y-axis direction satisfy: 1.27 ≤ fx / fy ≤ 1.

31.

12. The optical imaging lens group according to claim 11, characterized in that, The maximum TV distortion TDT within the imaging range of the optical imaging lens group satisfies: |TDT| ≤ 3.5%.

Images