Optical image capturing system

Abstract

The invention provides an optical imaging system. The optical imaging system comprises a lens barrel, a lens group and a spacing element group, wherein the lens group and the spacing element group are arranged in the lens barrel. The lens group is composed of eight lenses. The following conditions are satisfied: 4.50 lt; t45 / CP4lt, T45 / CP4lt; 20.98, 20.98; the following conditions are satisfied: 3.21 lt; d4m / CT5lt; and 4.81. The optical imaging system solves the problems that an eight-piece optical imaging system in the prior art restrains optical parameters of a middle lens to meet the requirement for high optical performance, so that the size of the middle lens is not uniform, the stress is too large after the middle lens is assembled, and the assembling reliability is affected.

Description

Technical Field

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

[0002] With the improvement of optical design and manufacturing technology, major manufacturers have higher and higher requirements for the optical performance and reliability of optical imaging systems. The eight-chip optical imaging system is widely used in mobile phone cameras, high-end cameras, medical imaging, industrial inspection and other fields because of its high optical performance and reliability. In order to meet high optical performance and high reliability, the design of the eight-chip optical imaging system faces many challenges.

[0003] At present, in order to meet the high optical performance requirements, eight-lens optical imaging systems usually need to constrain the optical parameters of the middle lens, especially the center thickness and focal length of the middle lens of the optical imaging system, so as to correct the aberration to ensure the imaging quality of the optical imaging system. However, in this case, the thickness of the middle lens is likely to be uneven, which increases the stress on the middle lens after assembly. The increased stress easily causes the lens to deform, reducing the assembly reliability of the lens and seriously affecting the assembly reliability of the optical imaging system.

[0004] That is to say, the eight-lens optical imaging system in the prior art constrains the optical parameters of the middle lens to meet the requirements of high optical performance, resulting in uneven size of the middle lens, which in turn leads to excessive stress after assembly of the middle lens, affecting assembly reliability. Summary of the invention

[0005] The main purpose of the present invention is to provide an optical imaging system to solve the problem that the optical parameters of the middle lens are constrained in the eight-lens optical imaging system in the prior art to meet the requirements of high optical performance, resulting in uneven size of the middle lens, which in turn leads to excessive stress on the middle lens after assembly, affecting assembly reliability.

[0006] To achieve the above object, according to one aspect of the present invention, an optical imaging system is provided, which includes a lens barrel and a lens group and a spacer element group disposed in the lens barrel. The lens group is composed of eight lenses. The eight lenses are, in order from the object side to the image side, a first lens with a positive or negative optical power, a second lens with a negative optical power, a third lens with a positive optical power, a fourth lens with a negative optical power, a fifth lens with a positive optical power, a sixth lens with a negative optical power, a seventh lens with a positive optical power, and an eighth lens with a negative optical power. Among the first lens to the eighth lens, the fifth lens has the largest central thickness on the optical axis of the optical imaging system. The spacer element group includes a first spacer element disposed between the first lens and the second lens and in partial contact with the image side surface of the first lens, a second spacer element disposed between the second lens and the third lens and in partial contact with the image side surface of the second lens, a third spacer element disposed between the third lens and the fourth lens and in partial contact with the image side surface of the third lens, a fourth spacer element disposed between the fourth lens and the fifth lens and in partial contact with the image side surface of the fourth lens, a fifth spacer element disposed between the fifth lens and the sixth lens and in partial contact with the image side surface of the fifth lens, a sixth spacer element disposed between the sixth lens and the seventh lens and in partial contact with the image side surface of the sixth lens, and a seventh spacer element disposed between the seventh lens and the eighth lens and in partial contact with the image side surface of the seventh lens. Among them, the air gap T45 between the fourth lens and the fifth lens on the optical axis and the maximum axial thickness CP4 of the fourth spacer element satisfy: 4.50 < T45 / CP4 < 20.98; the inner diameter d4m of the image side surface of the fourth spacer element and the central thickness CT5 of the fifth lens on the optical axis satisfy: 3.21 < d4m / CT5 < 4.81.

[0007] According to another aspect of the present invention, there is provided an optical imaging system including a lens barrel and a lens group and a spacer element group disposed in the lens barrel. The lens group is composed of eight lenses. The eight lenses are, in order from the object side to the image side, a first lens having a positive or negative optical power, a second lens having a negative optical power, a third lens having a positive optical power, a fourth lens having a negative optical power, a fifth lens having a positive optical power, a sixth lens having a negative optical power, a seventh lens having a positive optical power, and an eighth lens having a negative optical power. Among the first lens to the eighth lens, the fifth lens has the largest central thickness on the optical axis of the optical imaging system. The spacer element group includes a first spacer element disposed between the first lens and the second lens and in partial contact with the image side surface of the first lens, a second spacer element disposed between the second lens and the third lens and in partial contact with the image side surface of the second lens, a third spacer element disposed between the third lens and the fourth lens and in partial contact with the image side surface of the third lens, a fourth spacer element disposed between the fourth lens and the fifth lens and in partial contact with the image side surface of the fourth lens, a fifth spacer element disposed between the fifth lens and the sixth lens and in partial contact with the image side surface of the fifth lens, a sixth spacer element disposed between the sixth lens and the seventh lens and in partial contact with the image side surface of the sixth lens, and a seventh spacer element disposed between the seventh lens and the eighth lens and in partial contact with the image side surface of the seventh lens. Wherein, the inner diameter d4m of the image side surface of the fourth spacer element and the central thickness CT5 of the fifth lens on the optical axis satisfy: 3.21 < d4m / CT5 < 4.81. The axial distance SAG42 between the intersection point of the image side surface of the fourth lens and the optical axis and the vertex of the effective radius of the image side surface of the fourth lens and the maximum axial thickness CP4 of the fourth spacer element satisfy: 11.71 < SAG42 / CP4 < 22.19.

[0008] According to another aspect of the present invention, there is provided an optical imaging system, including a lens barrel and a lens group and a spacer element group disposed in the lens barrel. The lens group consists of eight lenses. The eight lenses are, in order from the object side to the image side, a first lens having a positive or negative optical power, a second lens having a negative optical power, a third lens having a positive optical power, a fourth lens having a negative optical power, a fifth lens having a positive optical power, a sixth lens having a negative optical power, a seventh lens having a positive optical power, and an eighth lens having a negative optical power; among the first lens to the eighth lens, the fifth lens has the largest central thickness on the optical axis of the optical imaging system; the spacer element group includes a first spacer element disposed between the first lens and the second lens and in partial contact with the image side surface of the first lens, a second spacer element disposed between the second lens and the third lens and in partial contact with the image side surface of the second lens, a third spacer element disposed between the third lens and the fourth lens and in partial contact with the image side surface of the third lens, a fourth spacer element disposed between the fourth lens and the fifth lens and in partial contact with the image side surface of the fourth lens, a fifth spacer element disposed between the fifth lens and the sixth lens and in partial contact with the image side surface of the fifth lens, a sixth spacer element disposed between the sixth lens and the seventh lens and in partial contact with the image side surface of the sixth lens, and a seventh spacer element disposed between the seventh lens and the eighth lens and in partial contact with the image side surface of the seventh lens; wherein, the effective focal length f4 of the fourth lens and the central thickness CT5 of the fifth lens on the optical axis satisfy: 4.90 < f4 / CT5 < 6.30; the inner diameter d4m of the image side surface of the fourth spacer element, the maximum axial thickness CP4 of the fourth spacer element, and the air gap T45 between the fourth lens and the fifth lens on the optical axis satisfy: 10.20 < d4m / (CP4 + T45) < 38.26.

[0009] Further, the effective focal length f4 of the fourth lens and the curvature radius R7 of the object side surface of the fourth lens satisfy: -4.85 < f4 / R7 < -1.62; the effective focal length f4 of the fourth lens and the inner diameter d3m of the image side surface of the third spacer element satisfy: -4.98 < f4 / d3m < -2.27.

[0010] Further, the air gap T67 between the sixth lens and the seventh lens on the optical axis, the air gap T78 between the seventh lens and the eighth lens on the optical axis, and the spacer distance EP67 on the optical axis from the image side surface of the sixth spacer element to the object side surface of the seventh spacer element satisfy: 0.44 < EP67 / (T78 - T67) < 3.11.

[0011] Further, among the adjacent two lenses of the first lens to the eighth lens, the air gap between the seventh lens and the eighth lens on the optical axis is the largest. The inner diameter d7m of the image side surface of the seventh spacer element and the air gap T78 between the seventh lens and the eighth lens on the optical axis satisfy: 5.37 < d7m / T78 < 8.42.

[0012] Further, the following relationships are satisfied between the outer diameter D1s of the object side surface of the first spacer element and the curvature radius R2 of the image side surface of the first lens: 1.65 < D1s / R2 < 2.74; and between the curvature radius R1 of the object side surface of the first lens and the central thickness CT1 of the first lens on the optical axis: 6.85 < R1 / CT1 < 9.49.

[0013] Further, the following relationship is satisfied between the axial distance EP12 on the optical axis from the image side surface of the first spacer element to the object side surface of the second spacer element and the air gap T23 on the optical axis between the second lens and the third lens: 4.05 < EP12 / T23 < 7.21.

[0014] Further, the following relationships are satisfied between the inner diameter d2m of the image side surface of the second spacer element and the central thickness CT3 of the third lens on the optical axis: 7.24 < d2m / CT3 < 9.20; and between the effective focal length f3 of the third lens and the inner diameter d2m of the image side surface of the second spacer element: 1.12 < f3 / d2m < 2.13.

[0015] Further, the following relationship is satisfied between the axial distance EP56 on the optical axis from the image side surface of the fifth spacer element to the object side surface of the sixth spacer element and the central thickness CT6 of the sixth lens on the optical axis: 1.47 < EP56 / CT6 < 4.58.

[0016] Further, the following relationship is satisfied among the effective focal length f5 of the fifth lens, the central thickness CT5 of the fifth lens on the optical axis, and the maximum axial thickness CP5 of the fifth spacer element: 1.82 < f5 / (CT5 + CP5) < 5.30.

[0017] Further, the following relationship is satisfied between the axial distance SAG42 on the optical axis from the intersection point of the image side surface of the fourth lens and the optical axis to the vertex of the effective radius of the image side surface of the fourth lens and the maximum axial thickness CP4 of the fourth spacer element: 11.71 < SAG42 / CP4 < 22.19.

[0018] Further, the following relationships are satisfied between the inner diameter d6s of the object side surface of the sixth spacer element and the central thickness CT6 of the sixth lens on the optical axis: 10.93 < d6s / CT6 < 17.99; and between the effective focal length f6 of the sixth lens and the outer diameter D6s of the object side surface of the sixth spacer element: -3.06 < f6 / D6s < -1.95.

[0019] Further, the central thickness CT7 of the seventh lens on the optical axis and the axial interval distance EP67 from the image side surface of the sixth spacer element to the object side surface of the seventh spacer element on the optical axis satisfy: 0.83 < CT7 / EP67 < 1.71; the effective focal length f7 of the seventh lens and the inner diameter d6m of the image side surface of the sixth spacer element satisfy: 1.37 < f7 / d6m < 3.08.

[0020] Further, the axial distance SAG12 between the intersection point of the image side surface of the first lens and the optical axis and the effective radius vertex of the image side surface of the first lens and the maximum axial thickness CP1 of the first spacer element satisfy: 16.65 < SAG12 / CP1 < 23.19.

[0021] Further, the air interval T78 between the seventh lens and the eighth lens on the optical axis and the central thickness CT8 of the eighth lens on the optical axis satisfy: 1.07 < T78 / CT8 < 3.45; the inner diameter d7m of the image side surface of the seventh spacer element, the air interval T78 between the seventh lens and the eighth lens on the optical axis and the central thickness CT8 of the eighth lens on the optical axis satisfy: 3.58 < d7m / (T78 + CT8) < 4.47.

[0022] Further, the spacer element group further includes an eighth spacer element disposed on the image side of the eighth lens and in partial contact with the image side surface of the eighth lens.

[0023] Further, the spacer element group further includes a fifth auxiliary spacer element disposed on the image side of the fifth spacer element and in partial contact with the image side surface of the fifth spacer element, and the maximum axial thickness CP5 of the fifth spacer element, the maximum axial thickness CP5b of the fifth auxiliary spacer element and the central thickness CT6 of the sixth lens on the optical axis satisfy: 0.82 < (CP5 + CP5b) / CT6 < 3.12.

[0024] Applying the technical solution of the present invention, the optical imaging system of the present application is composed of a lens barrel and eight lenses and multiple spacer elements arranged in the lens barrel. By reasonably arranging the optical powers of the eight lenses and the positions of the first spacer element to the seventh spacer element, and setting the central thickness of the fifth lens located in the middle of the optical imaging system to be the largest on the optical axis, it is ensured that the fifth lens can provide better optical performance, thereby enhancing the ability of the fifth lens to correct aberrations such as spherical aberration and coma. Moreover, the fifth lens has a positive optical power, and its thicker central part can help better control the light path, thereby optimizing the imaging quality of the optical imaging system. However, in this case, it is easy to make the thickness of the middle lens uneven, especially the thickness uniformity of the fourth lens and the fifth lens is poor, which increases the stress on the fourth lens and the fifth lens during assembly. The increase in stress easily causes deformation of the fourth lens and the fifth lens, reducing the assembly reliability of the lenses, and further seriously affecting the assembly reliability of the optical imaging system. Therefore, by restricting 4.50 < T45 / CP4 < 20.98 and 3.21 < d4m / CT5 < 4.81, it can ensure that the air gaps of the fourth lens and the fifth lens on the optical axis and the central thicknesses of the fourth lens and the fifth lens are appropriate, which helps to form a stronger structural support between the fourth lens, the fifth lens and the fourth spacer element, and avoid lens displacement or deformation of the fourth lens and the fifth lens caused by vibration or temperature change, thereby improving the assembly stability of the final optical imaging system and the structural stability. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] The accompanying drawings forming a part of this application are used to provide a further understanding of the present invention. The schematic embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation to the present invention. In the drawings:

[0026] Figure 1 shows the dimension marking diagram of the optical imaging system of an alternative embodiment of the present invention;

[0027] Figure 2 shows the structural schematic diagram of the optical imaging system of Embodiment 1-1 of the present invention;

[0028] Figure 3 shows the structural schematic diagram of the optical imaging system of Embodiment 1-2 of the present invention;

[0029] Figure 4 shows the structural schematic diagram of the optical imaging system of Embodiment 1-3 of the present invention;

[0030] Figures 5 to 7 respectively show the axial chromatic aberration curve, astigmatism curve and lateral chromatic aberration curve of the optical imaging system of Embodiment 1 of the present invention;

[0031] Figure 8A schematic structural diagram of an optical imaging system according to Embodiment 2-1 of the present invention is shown;

[0032] Fig. 9 A schematic structural diagram of an optical imaging system according to Embodiment 2-2 of the present invention is shown;

[0033] Fig.10 A schematic structural diagram of an optical imaging system according to Embodiment 2-3 of the present invention is shown;

[0034] Figures 11 to 13 The axial chromatic aberration curve, the astigmatism curve and the magnification chromatic aberration curve of the optical imaging system of the second embodiment of the present invention are respectively shown;

[0035] Fig.14 A schematic structural diagram of an optical imaging system according to Embodiment 3-1 of the present invention is shown;

[0036] Fig.15 A schematic structural diagram of an optical imaging system according to Embodiment 3-2 of the present invention is shown;

[0037] Fig.16 A schematic structural diagram of an optical imaging system according to Embodiment 3-3 of the present invention is shown;

[0038] Figures 17 to 19 The axial chromatic aberration curve, the astigmatism curve and the magnification chromatic aberration curve of the optical imaging system of the third embodiment of the present invention are respectively shown;

[0039] Fig. 20 and Fig.21 The stress cloud diagram and deformation cloud diagram of the optical imaging system of solution 1 of the present invention are respectively shown when the fifth lens has positive focal power and the center thickness on the optical axis is the largest, T45 / CP4=11.79 and d4m / CT5=3.89;

[0040] Fig. 22 and Fig.23 The stress cloud diagram and deformation cloud diagram of the optical imaging system of Comparative Example 1 are respectively shown when the fifth lens has positive power and the center thickness on the optical axis is the largest, T45 / CP4=1.27 and d4m / CT5=3.14;

[0041] Fig.24 and Fig.25 The stress cloud diagram and deformation cloud diagram of the optical imaging system of Comparative Example 2 are respectively shown when the fifth lens has positive power and the center thickness on the optical axis is the largest, T45 / CP4=23.17 and d4m / CT5=5.47;

[0042] Fig.26 A dimensioned diagram of an optical imaging system is shown according to an alternative embodiment of the present invention.

[0043] The above drawings include the following reference numerals:

[0044] P0, lens barrel; E1, first lens; S1, object side surface of first lens; S2, image side surface of first lens; E2, second lens; S3, object side surface of second lens; S4, image side surface of second lens; E3, third lens; S5, object side surface of third lens; S6, image side surface of third lens; E4, fourth lens; S7, object side surface of fourth lens; S8, image side surface of fourth lens; E5, fifth lens; S9, object side surface of fifth lens; S10, image side surface of fifth lens; E6, sixth lens; S11, object side surface of sixth lens; S12, image side surface of sixth lens; E7, seventh lens ; S13, the object side surface of the seventh lens; S14, the image side surface of the seventh lens; E8, the eighth lens; S15, the object side surface of the eighth lens; S16, the image side surface of the eighth lens; P1, the first spacing element; P2, the second spacing element; P3, the third spacing element; P3b, the third auxiliary spacing element; P3c, the third auxiliary spacing element; P4, the fourth spacing element; P5, the fifth spacing element; P5b, the fifth auxiliary spacing element; P5c, the fifth auxiliary spacing element; P6, the sixth spacing element; P7, the seventh spacing element; P7b, the seventh auxiliary spacing element; P8, the eighth spacing element. DETAILED DESCRIPTION

[0045] It should be noted that, in the absence of conflict, the embodiments and features in the embodiments of the present application can be combined with each other. The present invention will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

[0046] It should be noted that, unless otherwise specified, all technical and scientific terms used in this application have the same meanings as commonly understood by ordinary technicians in the technical field to which this application belongs.

[0047] In the present invention, unless otherwise specified, the directional words used, such as "up, down, top, bottom", usually refer to the directions shown in the drawings, or to the components themselves in the vertical, perpendicular or gravity directions; similarly, for ease of understanding and description, "inside and outside" refer to the inside and outside relative to the outline of each component itself, but the above-mentioned directional words are not used to limit the present invention.

[0048] It should be noted that in this specification, the expressions of first, second, third, etc. are only used to distinguish one feature from another feature, and do not represent any limitation on the features. Therefore, without departing from the teaching of the present application, the first lens discussed below may also be referred to as the second lens or the third lens.

[0049] In the drawings, the thickness, size and shape of the lenses have been slightly exaggerated for ease of illustration. Specifically, the shapes of the spherical or aspherical surfaces shown in the drawings are shown by way of example. That is, the shapes of the spherical or aspherical surfaces are not limited to the shapes of the spherical or aspherical surfaces shown in the drawings. The drawings are for illustration only and are not drawn strictly to scale.

[0050] In this article, the paraxial area refers to the area 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 area; 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 area. The judgment of the surface type in the paraxial area can be based on the judgment method of the general knowledge in this field, and the positive and negative R value (R refers to the radius of curvature of the paraxial area, usually refers to the R value on the lens database (lens data) in the optical software) is used to judge the concave and convex. For the object side, when the R value is positive, it is judged as a convex surface, and when the R value is negative, it is judged as a concave surface; for the image side, when the R value is positive, it is judged as a concave surface, and when the R value is negative, it is judged as a convex surface. In the present application, the left side is the object side and the right side is the image side.

[0051] In order to solve the problem in the prior art that an eight-lens optical imaging system constrains the optical parameters of a middle lens to meet the requirements of high optical performance, resulting in uneven size of the middle lens, which in turn leads to excessive stress on the middle lens after assembly, affecting assembly reliability, the present invention provides an optical imaging system.

[0052] like Figures 1 to 21 , Fig.26As shown, in an alternative embodiment of the present application, an optical imaging system is provided, which includes a lens barrel and a lens group and a spacer element group disposed in the lens barrel. The lens group is composed of eight lenses. The eight lenses are, in order from the object side to the image side, a first lens with a positive or negative optical power, a second lens with a negative optical power, a third lens with a positive optical power, a fourth lens with a negative optical power, a fifth lens with a positive optical power, a sixth lens with a negative optical power, a seventh lens with a positive optical power, and an eighth lens with a negative optical power. Among the first lens to the eighth lens, the fifth lens has the largest central thickness on the optical axis of the optical imaging system. The spacer element group includes a first spacer element disposed between the first lens and the second lens and in partial contact with the image side surface of the first lens, a second spacer element disposed between the second lens and the third lens and in partial contact with the image side surface of the second lens, a third spacer element disposed between the third lens and the fourth lens and in partial contact with the image side surface of the third lens, a fourth spacer element disposed between the fourth lens and the fifth lens and in partial contact with the image side surface of the fourth lens, a fifth spacer element disposed between the fifth lens and the sixth lens and in partial contact with the image side surface of the fifth lens, a sixth spacer element disposed between the sixth lens and the seventh lens and in partial contact with the image side surface of the sixth lens, and a seventh spacer element disposed between the seventh lens and the eighth lens and in partial contact with the image side surface of the seventh lens. Wherein, the air gap T45 between the fourth lens and the fifth lens on the optical axis and the maximum axial thickness CP4 of the fourth spacer element satisfy: 4.50 < T45 / CP4 < 20.98; the inner diameter d4m of the image side surface of the fourth spacer element and the central thickness CT5 of the fifth lens on the optical axis satisfy: 3.21 < d4m / CT5 < 4.81.

[0053] The optical imaging system of the present application consists of a lens barrel and eight lenses and multiple spacer elements disposed in the lens barrel. By reasonably arranging the optical powers of the eight lenses and the positions of the first to seventh spacer elements, and setting the central thickness of the fifth lens located in the middle of the optical imaging system to be the largest on the optical axis, it is ensured that the fifth lens can provide better optical performance, thereby enhancing the ability of the fifth lens to correct aberrations such as spherical aberration and coma. Moreover, the fifth lens has a positive optical power, and its thicker central part can help better control the light path, thereby optimizing the imaging quality of the optical imaging system. However, in this case, it is easy to make the thickness of the middle lenses uneven, especially the thickness uniformity of the fourth and fifth lenses is poor, which increases the stress on the fourth and fifth lenses during assembly. The increase in stress easily causes deformation of the fourth and fifth lenses, reducing the assembly reliability of the lenses, and进而 seriously affecting the assembly reliability of the optical imaging system. Therefore, by restricting 4.50 < T45 / CP4 < 20.98 and 3.21 < d4m / CT5 < 4.81, it can be ensured that the air gaps of the fourth and fifth lenses on the optical axis and the central thicknesses of the fourth and fifth lenses are appropriate, which helps to form a stronger structural support between the fourth lens, the fifth lens, and the fourth spacer element, avoiding lens displacement or deformation of the fourth and fifth lenses caused by vibration or temperature changes, thereby improving the assembly stability of the final optical imaging system and the structural stability.

[0054] In addition, referring to Table 1 below, Figure 20 to Figure 25 as shown, on the premise that the optical imaging system satisfies that the fifth lens has a positive optical power and the central thickness of the fifth lens on the optical axis is the largest, Fig. 20 and Fig.21 respectively show the stress nephogram and deformation nephogram of the optical imaging system of Solution 1 of the present invention when T45 / CP4 = 11.79 and d4m / CT5 = 3.89; Fig. 22 and Fig.23 respectively show the stress nephogram and deformation nephogram of the optical imaging system of Comparative Example 1 when T45 / CP4 = 1.27 and d4m / CT5 = 3.14;

[0055] Fig.24 and Fig.25 respectively show the stress nephogram and deformation nephogram of the optical imaging system of Comparative Example 2 when T45 / CP4 = 23.17 and d4m / CT5 = 5.47.

[0056] From Figure 20 to Figure 25It can be seen that when the optical imaging system satisfies T45 / CP4 = 11.79 and d4m / CT5 = 3.89, under the same assembly pressure, the stresses on the fourth lens and the fifth lens are relatively small, avoiding the risk of deformation or movement of the fourth lens and the fifth lens during assembly, and the overall performance is better. When the optical imaging system satisfies T45 / CP4 = 1.27 and d4m / CT5 = 3.14, the air gap between the fourth lens and the fifth lens on the optical axis is relatively small. During the assembly process, the fourth lens, the fifth lens, and the sixth lens are prone to deformation, which may lead to scratches on the lens surface, and the assembly reliability of the optical imaging system is poor. When the optical imaging system satisfies T45 / CP4 = 23.17 and d4m / CT5 = 5.47, the thickness of the fourth lens is uneven. During the assembly process, stress concentration is likely to occur between the fourth lens and the fifth lens, resulting in poor assembly reliability of the optical imaging system. Thus, it can be seen that when the fifth lens has a positive optical power and the maximum center thickness on the optical axis, T45 / CP4 is in the range of 4.50 to 20.98, and d4m / CT5 is in the range of 3.21 to 4.81, during the assembly process of the optical imaging system, the assembly stresses of the fourth lens and the fifth lens are the smallest, the deformation amount is the smallest, the assembly reliability is the best, and the overall performance is the best. Therefore, by restricting 4.50 < T45 / CP4 < 20.98 and 3.21 < d4m / CT5 < 4.81 in this application, it can ensure that the air gap between the fourth lens and the fifth lens on the optical axis and the center thickness of the fourth lens and the fifth lens are appropriate, which helps to form a stronger structural support between the fourth lens, the fifth lens, and the fourth spacer element, avoiding lens displacement or deformation caused by vibration or temperature changes of the fourth lens and the fifth lens, thereby improving the assembly stability of the final optical imaging system and the stability of the structure.

[0057] Table 1

[0058] Solution 1 of the present invention Comparative Example 1 Comparative Example 2 T45 / CP4 11.79 1.27 23.17 d4m / CT5 3.89 3.14 5.47

[0059] In this embodiment, the spacer element group further includes an eighth spacer element disposed on the image side of the eighth lens and in partial contact with the image side surface of the eighth lens, and a fifth auxiliary spacer element disposed on the image side of the fifth spacer element and in partial contact with the image side surface of the fifth spacer element. By providing multiple spacer elements, additional fixation and support are provided for the first lens to the eighth lens, which helps to prevent the first lens to the eighth lens from displacing or loosening during assembly or use, thereby ensuring the stability and reliability of the entire optical imaging system.

[0060] In this embodiment, the following conditions are satisfied between the effective focal length f4 of the fourth lens and the curvature radius R7 of the object side surface of the fourth lens: -4.85 < f4 / R7 < -1.62; and the following condition is satisfied between the effective focal length f4 of the fourth lens and the inner diameter d3m of the image side surface of the third spacer element: -4.98 < f4 / d3m < -2.27. By controlling these two conditional expressions, the relationship between the effective focal length of the fourth lens, the curvature radius of the object side surface of the fourth lens, and the inner diameter of the image side surface of the third spacer element can be restricted, which helps to optimize the effective focal length of the optical imaging system and the position of the imaging surface, thereby controlling the light path to correct the aberration generated when light passes through the fourth lens, reducing the aberration, and improving the imaging quality of the optical imaging system.

[0061] In this embodiment, the following condition is satisfied among the air gap T67 between the sixth lens and the seventh lens on the optical axis, the air gap T78 between the seventh lens and the eighth lens on the optical axis, and the interval distance EP67 on the optical axis from the image side surface of the sixth spacer element to the object side surface of the seventh spacer element: 0.44 < EP67 / (T78 - T67) < 3.11. By controlling this conditional expression, the difference between the air gap between the seventh lens and the eighth lens on the optical axis and the air gap between the sixth lens and the seventh lens on the optical axis can be restricted within a reasonable range, which helps to ensure that the air gaps between adjacent two of the sixth lens, the seventh lens, and the eighth lens are appropriate, avoiding the situations of too large or too small gaps, thereby enhancing the compactness and stability of the arrangement of the sixth lens, the seventh lens, and the eighth lens in the lens barrel. At the same time, it can also reduce the errors generated during the manufacturing process, achieve high-precision manufacturing and assembly of the optical imaging system, and further improve the overall performance of the optical imaging system.

[0062] In this embodiment, among adjacent two of the first lens to the eighth lens, the air gap between the seventh lens and the eighth lens on the optical axis is the largest. The following condition is satisfied between the inner diameter d7m of the image side surface of the seventh spacer element and the air gap T78 between the seventh lens and the eighth lens on the optical axis: 5.37 < d7m / T78 < 8.42. By reasonably controlling that the air gap between the seventh lens and the eighth lens is the largest and this conditional expression, a doublet lens with an air gap can be formed by the seventh lens and the eighth lens, and the air gap between the seventh lens and the eighth lens on the optical axis can be maintained at the largest, so that this doublet lens can minimize the light transmission wavefront error, spot size, and aberration, ensure the imaging quality of the optical imaging system, and further improve the overall performance of the optical imaging system.

[0063] In this embodiment, the following relationships are satisfied between the outer diameter D1s of the object side surface of the first spacer element and the radius of curvature R2 of the image side surface of the first lens: 1.65 < D1s / R2 < 2.74; and between the radius of curvature R1 of the object side surface of the first lens and the central thickness CT1 of the first lens on the optical axis: 6.85 < R1 / CT1 < 9.49. The radius of curvature of the lens and the central thickness on the optical axis together determine the effective focal length of the lens. By controlling these two conditional expressions, the radius of curvature of the two side surfaces of the first lens and the central thickness of the first lens on the optical axis can be controlled to adjust the effective focal length of the first lens to meet the application requirements of a specific scenario. At the same time, the outer diameter of the object side surface of the first spacer element can be restricted, which is beneficial to controlling the aperture of the first lens, beneficial to controlling the transmission and focusing of light, and ensuring that the light can maintain the required quality, shape, and trend when passing through the optical imaging system.

[0064] In this embodiment, the following relationship is satisfied between the axial distance EP12 from the image side surface of the first spacer element to the object side surface of the second spacer element on the optical axis and the air gap T23 between the second lens and the third lens on the optical axis: 4.05 < EP12 / T23 < 7.21. By controlling this conditional expression, the relationship between the axial distance from the image side surface of the first spacer element to the object side surface of the second spacer element on the optical axis and the air gap between the second lens and the third lens on the optical axis can be controlled, improving the processing feasibility and assembly convenience of the second lens, the third lens, the first spacer element, and the second spacer element. Furthermore, the misalignment amount during the assembly of the second lens and the third lens can be reduced, effectively improving the assembly stability of the optical imaging system, and thus being beneficial to improving the reliability and durability of the optical imaging system.

[0065] In this embodiment, the following relationships are satisfied between the inner diameter d2m of the image side surface of the second spacer element and the central thickness CT3 of the third lens on the optical axis: 7.24 < d2m / CT3 < 9.20; and between the effective focal length f3 of the third lens and the inner diameter d2m of the image side surface of the second spacer element: 1.12 < f3 / d2m < 2.13. By controlling these two conditional expressions, the relationship between the inner diameter of the image side surface of the second spacer element, the central thickness of the third lens on the optical axis, and the effective focal length of the third lens can be controlled, which helps to balance the optical performance and production cost of the optical imaging system, that is, reducing the manufacturing cost and complexity of the optical imaging system while ensuring the imaging quality.

[0066] In this embodiment, the distance EP56 on the optical axis from the image side of the fifth spacer element to the object side of the sixth spacer element satisfies 1.47 < EP56 / CT6 < 4.58 with respect to the central thickness CT6 of the sixth lens on the optical axis. EP56 and CT6 are important parameters affecting the focusing performance and imaging quality of the optical imaging system. EP56 can adjust the path length of light in the optical imaging system, while CT6 can affect the degree of refraction of light by the sixth lens. By controlling this conditional expression, key performance indicators such as the effective focal length, spot size, and light quality of the optical imaging system can be regulated, thereby ensuring the imaging quality of the optical imaging system.

[0067] In this embodiment, the effective focal length f5 of the fifth lens, the central thickness CT5 of the fifth lens on the optical axis, and the maximum axial thickness CP5 of the fifth spacer element satisfy 1.82 < f5 / (CT5 + CP5) < 5.30. CT5 and CP5 can jointly affect the overall optical length and light trend of the optical imaging system. By controlling this conditional expression, the thickness measurement accuracy and positioning accuracy of the fifth lens can be improved, and the risk of reducing the imaging quality of the optical imaging system caused by processing errors or assembly errors of the fifth lens can be avoided.

[0068] In this embodiment, the axial distance SAG42 on the optical axis from the intersection of the image side of the fourth lens and the optical axis to the vertex of the effective radius of the image side of the fourth lens satisfies 11.71 < SAG42 / CP4 < 22.19 with respect to the maximum axial thickness CP4 of the fourth spacer element. SAG42 affects the radius of curvature of the image side of the fourth lens, while CP4 affects the path and length of light. By controlling this conditional expression, the forming stability and assembly stability of the fourth lens can be ensured, and the light collection ability and resolution of the fourth lens can be optimized, thereby improving the light focusing ability and imaging quality of the optical imaging system.

[0069] In this embodiment, the inner diameter d6s of the object side of the sixth spacer element satisfies 10.93 < d6s / CT6 < 17.99 with respect to the central thickness CT6 of the sixth lens on the optical axis; the effective focal length f6 of the sixth lens satisfies -3.06 < f6 / D6s < -1.95 with respect to the outer diameter D6s of the object side of the sixth spacer element. By controlling the ratio of the inner diameter of the object side of the sixth spacer element to the central thickness of the sixth lens on the optical axis, the coma, astigmatism, and other aberrations of the sixth lens can be corrected to a certain extent, thereby improving the imaging quality. At the same time, by restricting the ratio of the effective focal length of the sixth lens to the outer diameter of the object side of the sixth spacer element, the spherical aberration and chromatic aberration generated by the sixth lens can be reduced, optimizing the imaging quality of the optical imaging system.

[0070] In this embodiment, the central thickness CT7 of the seventh lens on the optical axis and the axial distance EP67 on the optical axis from the image side surface of the sixth spacer element to the object side surface of the seventh spacer element satisfy: 0.83 < CT7 / EP67 < 1.71; the effective focal length f7 of the seventh lens and the inner diameter d6m of the image side surface of the sixth spacer element satisfy: 1.37 < f7 / d6m < 3.08. By controlling the ratio of the central thickness of the seventh lens on the optical axis to the axial distance on the optical axis from the image side surface of the sixth spacer element to the object side surface of the seventh spacer element, it helps to optimize the propagation path of light inside the optical imaging system, reduce unnecessary light loss and the generation of aberrations, improve the imaging quality of the optical imaging system. At the same time, by restricting the ratio of the effective focal length of the seventh lens to the inner diameter of the image side surface of the sixth spacer element, the distribution of the effective focal length of the seventh lens in the optical imaging system can be optimized, making the optical imaging system more balanced and efficient.

[0071] In this embodiment, the axial distance SAG12 on the optical axis between the intersection point of the image side surface of the first lens and the optical axis and the vertex of the effective radius of the image side surface of the first lens and the maximum axial thickness CP1 of the first spacer element satisfy: 16.65 < SAG12 / CP1 < 23.19. By controlling this conditional expression, it helps to enhance the stability of the optical imaging system, enabling the optical imaging system to maintain good imaging performance even when the temperature or humidity changes, and improving the reliability of the optical imaging system.

[0072] In this embodiment, the air gap T78 between the seventh lens and the eighth lens on the optical axis and the central thickness CT8 of the eighth lens on the optical axis satisfy: 1.07 < T78 / CT8 < 3.45; the inner diameter d7m of the image side surface of the seventh spacer element, the air gap T78 between the seventh lens and the eighth lens on the optical axis and the central thickness CT8 of the eighth lens on the optical axis satisfy: 3.58 < d7m / (T78 + CT8) < 4.47. By controlling these two conditional expressions, the propagation path and deflection degree of light when passing through the seventh lens and the eighth lens can be adjusted, improving the imaging quality of the optical imaging system. At the same time, it is also beneficial to the molding stability of the injection molding process of the seventh lens and the eighth lens, thereby improving the processability of the optical imaging system.

[0073] In this embodiment, the maximum axial thickness CP5 of the fifth spacer element, the maximum axial thickness CP5b of the fifth auxiliary spacer element and the center thickness CT6 of the sixth lens on the optical axis satisfy: 0.82<(CP5+CP5b) / CT6<3.12. The optical imaging system introduces the fifth auxiliary spacer element. By controlling this conditional expression, the propagation path of light between the fifth lens and the sixth lens can be appropriately adjusted to reduce unnecessary light loss, and aberrations caused by improper air spacing between lenses or mismatched lens thickness can be avoided, which helps to improve the imaging quality of the optical imaging system and make the imaging clearer and sharper.

[0074] In this embodiment, the object side surface of the first lens is convex, and the image side surface of the first lens is concave; the object side surface of the second lens is convex, and the image side surface of the second lens is concave; the object side surface of the third lens is convex; the object side surface of the fourth lens is convex, and the image side surface of the fourth lens is concave; the object side surface of the fifth lens is convex, and the image side surface of the fifth lens is convex; the object side surface of the sixth lens is convex, and the image side surface of the sixth lens is concave; the object side surface of the seventh lens is convex. By rationally planning the surface shape of each lens, it is helpful to regulate the light trend, eliminate aberrations, and ensure imaging quality.

[0075] Optionally, the optical imaging system in the embodiments of the present application can be simulated by software and / or tools such as ZEMAX, CODEV, etc. In the process of simulation using the above software and / or tools, the surface profile of each lens can be simulated and appropriately adjusted according to the surface profile of the software and / or tool used.

[0076] In addition, in another alternative embodiment of the present application, an optical imaging system is further provided, which includes a lens barrel and a lens group and a spacer element group disposed in the lens barrel. The lens group is composed of eight lenses. The eight lenses are, in order from the object side to the image side, a first lens with a positive or negative optical power, a second lens with a negative optical power, a third lens with a positive optical power, a fourth lens with a negative optical power, a fifth lens with a positive optical power, a sixth lens with a negative optical power, a seventh lens with a positive optical power, and an eighth lens with a negative optical power. Among the first lens to the eighth lens, the fifth lens has the largest central thickness on the optical axis of the optical imaging system. The spacer element group includes a first spacer element disposed between the first lens and the second lens and in partial contact with the image side surface of the first lens, a second spacer element disposed between the second lens and the third lens and in partial contact with the image side surface of the second lens, a third spacer element disposed between the third lens and the fourth lens and in partial contact with the image side surface of the third lens, a fourth spacer element disposed between the fourth lens and the fifth lens and in partial contact with the image side surface of the fourth lens, a fifth spacer element disposed between the fifth lens and the sixth lens and in partial contact with the image side surface of the fifth lens, a sixth spacer element disposed between the sixth lens and the seventh lens and in partial contact with the image side surface of the sixth lens, and a seventh spacer element disposed between the seventh lens and the eighth lens and in partial contact with the image side surface of the seventh lens. Among them, the inner diameter d4m of the image side surface of the fourth spacer element and the central thickness CT5 of the fifth lens on the optical axis satisfy: 3.21 < d4m / CT5 < 4.8; the axial distance SAG42 between the intersection point of the image side surface of the fourth lens and the optical axis and the vertex of the effective radius of the image side surface of the fourth lens and the maximum axial thickness CP4 of the fourth spacer element satisfy: 11.71 < SAG42 / CP4 < 22.19.

[0077] The optical imaging system of the present application consists of a lens barrel and eight lenses and multiple spacer elements arranged in the lens barrel. By reasonably arranging the optical powers of the eight lenses and the positions of the first spacer element to the seventh spacer element, and setting the central thickness of the fifth lens located in the middle of the optical imaging system to be the largest on the optical axis, it is ensured that the fifth lens can provide better optical performance, thereby enhancing the ability of the fifth lens to correct aberrations such as spherical aberration and coma. Moreover, the fifth lens has a positive optical power, and its thicker central part can help better control the light path, thus optimizing the imaging quality of the optical imaging system. However, in this case, it is easy to make the thickness of the middle lens uneven, especially the thickness uniformity of the fourth lens and the fifth lens is poor, which increases the stress on the fourth lens and the fifth lens during assembly. The increase in stress easily causes deformation of the fourth lens and the fifth lens, reducing the assembly reliability of the lenses, and further seriously affecting the assembly reliability of the optical imaging system. Therefore, by restricting 3.21 < d4m / CT5 < 4.81 and 11.71 < SAG42 / CP4 < 22.19 in the present application, it helps to form a stronger structural support between the fourth lens, the fifth lens and the fourth spacer element, which can ensure the forming stability and assembly stability of the fourth lens, avoid lens displacement or deformation of the fourth lens and the fifth lens caused by vibration or temperature change, thereby improving the assembly stability and structural stability of the final optical imaging system; it can also optimize the light collection ability and resolution of the fourth lens, and further improve the light focusing ability and imaging quality of the optical imaging system.

[0078] Of course, other parametric forms in the above embodiments may also be included in this embodiment, which will not be elaborated here one by one.

[0079] In addition, in another alternative embodiment of the present application, an optical imaging system is further provided, which includes a lens barrel and a lens group and a spacer element group disposed in the lens barrel. The lens group is composed of eight lenses. The eight lenses are, in order from the object side to the image side, a first lens with a positive or negative optical power, a second lens with a negative optical power, a third lens with a positive optical power, a fourth lens with a negative optical power, a fifth lens with a positive optical power, a sixth lens with a negative optical power, a seventh lens with a positive optical power, and an eighth lens with a negative optical power. Among the first lens to the eighth lens, the fifth lens has the largest central thickness on the optical axis of the optical imaging system. The spacer element group includes a first spacer element disposed between the first lens and the second lens and in partial contact with the image side surface of the first lens, a second spacer element disposed between the second lens and the third lens and in partial contact with the image side surface of the second lens, a third spacer element disposed between the third lens and the fourth lens and in partial contact with the image side surface of the third lens, a fourth spacer element disposed between the fourth lens and the fifth lens and in partial contact with the image side surface of the fourth lens, a fifth spacer element disposed between the fifth lens and the sixth lens and in partial contact with the image side surface of the fifth lens, a sixth spacer element disposed between the sixth lens and the seventh lens and in partial contact with the image side surface of the sixth lens, and a seventh spacer element disposed between the seventh lens and the eighth lens and in partial contact with the image side surface of the seventh lens. Among them, the following relationships are satisfied between the effective focal length f4 of the fourth lens and the central thickness CT5 of the fifth lens on the optical axis: 4.90 < f4 / CT5 < 6.30. The following relationships are satisfied between the inner diameter d4m of the image side surface of the fourth spacer element, the maximum axial thickness CP4 of the fourth spacer element, and the air gap T45 between the fourth lens and the fifth lens on the optical axis: 10.20 < d4m / (CP4 + T45) < 38.26.

[0080] The optical imaging system of the present application consists of a lens barrel and eight lenses and multiple spacer elements arranged in the lens barrel. By reasonably arranging the optical powers of the eight lenses and the positions of the first to seventh spacer elements, and setting the central thickness of the fifth lens located in the middle of the optical imaging system to be the largest on the optical axis, it is ensured that the fifth lens can provide better optical performance, thereby enhancing the ability of the fifth lens to correct aberrations such as spherical aberration and coma. Moreover, the fifth lens has a positive optical power, and its thicker central part can help better control the light path, thus optimizing the imaging quality of the optical imaging system. However, in this case, it is easy to make the thickness of the middle lenses uneven, especially the thickness uniformity of the fourth lens and the fifth lens is poor, which increases the stress on the fourth lens and the fifth lens during assembly. The increase in stress easily causes deformation of the fourth lens and the fifth lens, reducing the assembly reliability of the lenses and seriously affecting the assembly reliability of the optical imaging system. Therefore, in the present application, by restricting 4.90 < f4 / CT5 < 6.30 and 10.20 < d4m / (CP4 + T45) < 38.26, the ratio of the effective focal length of the fourth lens to the central thickness of the fifth lens on the optical axis and the relationship between the inner diameter of the image side of the fourth spacer element, the maximum axial thickness of the fourth spacer element and the air gap between the fourth lens and the fifth lens on the optical axis are controlled. On the basis of ensuring the optical performance of the fourth lens and the fifth lens, it is ensured that the distance between the fourth lens and the fifth lens is appropriate, and at the same time, the rationality of the shapes and sizes of the fourth lens and the fifth lens can be restricted, which is beneficial to reducing the phenomenon of stress concentration between the fourth lens and the fifth lens after assembly, avoiding the risk of deformation of the fourth lens and the fifth lens, and thus improving the assembly stability of the final optical imaging system and the structural stability.

[0081] Of course, other parametric forms in the above embodiments may also be included in this embodiment, which will not be elaborated here one by one.

[0082] Optionally, the above optical imaging system may further include a protective glass for protecting the photosensitive element located on the imaging surface.

[0083] In the optical imaging system of the present application, multiple lenses can be used, such as the eight lenses mentioned above. In the present application, at least one of the lens surfaces of each lens is an aspherical surface. The characteristics of an aspherical lens are 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 the aberrations that occur during imaging as much as possible, thereby improving the imaging quality.

[0084] However, those skilled in the art should understand that, without departing from the technical solution claimed in the present application, the number of lenses constituting the optical imaging system 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 embodiments, the optical imaging system is not limited to including eight lenses. If necessary, the optical imaging system may also include other numbers of lenses.

[0085] Figure 1 and Fig.26 A dimension-marked schematic diagram of an optical imaging system of the present application is shown. Figure 1 Parameters such as D1s, d2m, d3m, d4m, d6s, d6m, D6s, d7m, CP1, EP12, CP4, CP5, EP56, and EP67 are indicated in the figure. Fig.26 SAG12, SAG42 and CP5b are marked in the middle to clearly and intuitively understand the meaning of the parameters. In order to facilitate the description of the optical imaging system and the surface shape of the specific lens, these parameters will no longer be reflected in the drawings when the specific embodiments are described later.

[0086] The following further describes examples of specific surface shapes and parameters of the optical imaging system applicable to the above-mentioned embodiments with reference to the accompanying drawings.

[0087] It should be noted that in the following embodiment 1, there are three examples of embodiment 1-1, embodiment 1-2, and embodiment 1-3; in embodiment 2, there are three examples of embodiment 2-1, embodiment 2-2, and embodiment 2-3; and in embodiment 3, there are three examples of embodiment 3-1, embodiment 3-2, and embodiment 3-3. In the three examples of the same embodiment, the parameters such as the radius of curvature, center thickness, and spacing distance between lenses of the optical imaging system from the first lens to the eighth lens, as well as the coefficients of high-order terms are the same, but the parameters such as the thickness, inner diameter, and outer diameter of the lens barrel, the first spacing element to the eighth spacing element are different. In other words, the main structure for imaging is the same, but the auxiliary structure for imaging is different.

[0088] It should be noted that any one of the following examples 1 to 3 is applicable to all implementation methods of the present application.

[0089] Embodiment 1

[0090] like Figures 2 to 7 As shown, the optical imaging system of embodiment 1 is described. Figure 2 shows a schematic structural diagram of the optical imaging system of Example 1-1, Figure 3 shows a schematic structural diagram of the optical imaging system of Embodiment 1-2, Figure 4 A schematic structural diagram of the optical imaging system of Embodiments 1-3 is shown.

[0091] like Figures 2 to 4 As shown, the optical imaging system includes a lens barrel P0 and a first lens E1, a first spacing element P1, a second lens E2, a second spacing element P2, a third lens E3, a third spacing element P3, a fourth lens E4, a fourth spacing element P4, a fifth lens E5, a fifth spacing element P5, a sixth lens E6, a sixth spacing element P6, a seventh lens E7, a seventh spacing element P7, an eighth lens E8, and an eighth spacing element P8, which are arranged in sequence in the lens barrel P0 from the object side to the image side along the optical axis.

[0092] like Figure 2 As shown, it is a structural schematic diagram of the optical imaging system of Example 1-1. In this example, the object side surface and image side surface of the first spacer element P1 are in partial contact with the image side surface S2 of the first lens and the object side surface S3 of the second lens, respectively. The object side surface and image side surface of the second spacer element P2 are in partial contact with the image side surface S4 of the second lens and the object side surface S5 of the third lens, respectively. The object side surface and image side surface of the third spacer element P3 are in partial contact with the image side surface S6 of the third lens and the object side surface S7 of the fourth lens, respectively. The object side surface and image side surface of the fourth spacer element P4 are in partial contact with the image side surface S8 of the fourth lens and the object side surface S9 of the fifth lens, respectively. The object side surface and image side surface of the fifth spacer element P5 are in partial contact with the image side surface S10 of the fifth lens and the object side surface S11 of the sixth lens, respectively. The object side surface and image side surface of the sixth spacer element P6 are in partial contact with the image side surface S12 of the sixth lens and the object side surface S13 of the seventh lens, respectively. The object side surface and image side surface of the seventh spacer element P7 are in partial contact with the image side surface S14 of the seventh lens and the object side surface S15 of the eighth lens, respectively. The object-side surface of the eighth spacer element P8 is in partial contact with the image-side surface S16 of the eighth lens.

[0093] like Figure 3 FIG. 1 is a schematic diagram of the structure of the optical imaging system of Example 1-2. In this example, the supporting and abutting manner of each spacing element is the same as that of Example 1-1, and the relevant description in Example 1-1 may be referred to, and will not be repeated here.

[0094] like Figure 4As shown, it is a schematic diagram of the structure of the optical imaging system of Example 1-3. In this example, the image side of the fifth spacer element P5 is also provided with a fifth auxiliary spacer element P5b and a fifth auxiliary spacer element P5c in sequence. At this time, the image side surface of the fifth spacer element P5 is in partial contact with the object side surface of the fifth auxiliary spacer element P5b, the image side surface of the fifth auxiliary spacer element P5b is in partial contact with the object side surface of the fifth auxiliary spacer element P5c, and the image side surface of the fifth auxiliary spacer element P5c is in partial contact with the object side surface S11 of the sixth lens. In addition, the supporting and abutting manner of the remaining spacer elements is the same as that of Example 1-1, and the relevant description in Example 1-1 may be referred to, and no further description is given here.

[0095] In summary, the structural parameters of the optical imaging system of Example 1 in Example 1-1, Example 1-2, and Example 1-3 are shown in Table 2 (unit: mm).

[0096] Table 2

[0097] Parameters / Examples 1-1 1-2 1-3 D1s 4.914 5.900 5.910 d2m 4.098 4.054 4.154 d3m 4.059 4.015 4.115 d4m 4.637 4.593 4.493 d6s 5.927 5.883 6.027 d6m 5.927 5.883 5.983 D6s 8.261 8.161 8.206 d7m 6.536 6.492 6.792 CP1 0.020 0.021 0.022 EP12 0.335 0.345 0.357 CP4 0.020 0.021 0.022 CP5 1.076 1.076 0.022 EP56 0.532 0.632 1.586 EP67 0.499 0.509 0.511 CP5b 1.054

[0098] In Embodiment 1, the object side surface S1 of the first lens is a convex surface, and the image side surface S2 of the first lens is a concave surface. The object side surface S3 of the second lens is a convex surface, and the image side surface S4 of the second lens is a concave surface. The object side surface S5 of the third lens is a convex surface, and the image side surface S6 of the third lens is a convex surface. The object side surface S7 of the fourth lens is a convex surface, and the image side surface S8 of the fourth lens is a concave surface. The object side surface S9 of the fifth lens is a convex surface, and the image side surface S10 of the fifth lens is a convex surface. The object side surface S11 of the sixth lens is a convex surface, and the image side surface S12 of the sixth lens is a concave surface. The object side surface S13 of the seventh lens is a convex surface, and the image side surface S14 of the seventh lens is a convex surface. The object side surface S15 of the eighth lens is a concave surface, and the image side surface S16 of the eighth lens is a convex surface.

[0099] In Example 1, the effective focal length f of the optical imaging system is 5.97 mm, the effective focal length f1 of the first lens is 52.46 mm, the effective focal length f2 of the second lens is -11.39 mm, the effective focal length f3 of the third lens is 4.86 mm, the effective focal length f4 of the fourth lens is -9.60 mm, the effective focal length f5 of the fifth lens is 5.24 mm, the effective focal length f6 of the sixth lens is -16.51 mm, the effective focal length f7 of the seventh lens is 8.46 mm, the effective focal length f8 of the eighth lens is -4.83 mm, the axial distance SAG12 from the intersection of the image side surface of the first lens and the optical axis to the vertex of the effective radius of the image side surface of the first lens is 0.46 mm, and the axial distance SAG42 from the intersection of the image side surface of the fourth lens and the optical axis to the vertex of the effective radius of the image side surface of the fourth lens is 0.44 mm.

[0100] Table 3 shows a basic structural parameter table of the optical imaging system of Example 1, wherein the units of the radius of curvature and thickness / distance are all millimeters.

[0101] Table 3

[0102]

[0103]

[0104] In the first embodiment, the object-side surface and the image-side surface of the first lens E1 to the eighth lens E8 are all aspherical surfaces, and the surface shape of each aspherical lens can be defined by but not limited to the following aspherical surface formula:

[0105]

[0106] Wherein, x is the distance vector height from the vertex of the aspheric surface when the aspheric surface is at a height of h along the optical axis; c is the paraxial curvature of the aspheric surface, c=1 / R, that is, the paraxial curvature c is the reciprocal of the curvature radius R in the above Table 3; k is the cone coefficient; Ai is the correction coefficient of the i-th order of the aspheric surface. The following Table 4 gives the high-order coefficients A4, A6, A8, A10, A12, A14, A16 and A18 that can be used for each aspheric mirror surface S1-S16 in Example 1.

[0107] Table 4

[0108]

[0109]

[0110] Figure 5 The axial chromatic aberration curve of the optical imaging system of the first embodiment is shown, which indicates the deviation of the focal point of light of different wavelengths after passing through the light imaging system. Figure 6 The astigmatism curve of the optical imaging system of the first embodiment is shown, which represents the meridional image plane curvature and the sagittal image plane curvature. Figure 7 The magnification chromatic aberration curve of the optical imaging system of the first embodiment is shown, which represents the deviation of different image heights on the imaging surface after the light passes through the optical imaging system.

[0111] according to Figures 5 to 7 It can be seen that the optical imaging system provided in the first embodiment can achieve good imaging quality.

[0112] Embodiment 2

[0113] like Figures 8 to 13 As shown, the optical imaging system of the second embodiment is described. Figure 8 shows a schematic structural diagram of the optical imaging system of Example 2-1, Fig. 9 shows a schematic structural diagram of the optical imaging system of Example 2-2, Fig.10 A schematic structural diagram of the optical imaging system of Example 2-3 is shown.

[0114] like Figures 8 to 10 As shown, the optical imaging system includes a lens barrel P0 and a first lens E1, a first spacing element P1, a second lens E2, a second spacing element P2, a third lens E3, a third spacing element P3, a fourth lens E4, a fourth spacing element P4, a fifth lens E5, a fifth spacing element P5, a sixth lens E6, a sixth spacing element P6, a seventh lens E7, a seventh spacing element P7, an eighth lens E8, and an eighth spacing element P8, which are arranged in sequence in the lens barrel P0 from the object side to the image side along the optical axis.

[0115] like Figure 8 As shown, it is a structural schematic diagram of the optical imaging system of Example 2-1. In this example, the object side surface and image side surface of the first spacer element P1 are in partial contact with the image side surface S2 of the first lens and the object side surface S3 of the second lens, respectively. The object side surface and image side surface of the second spacer element P2 are in partial contact with the image side surface S4 of the second lens and the object side surface S5 of the third lens, respectively. The object side surface and image side surface of the third spacer element P3 are in partial contact with the image side surface S6 of the third lens and the object side surface S7 of the fourth lens, respectively. The object side surface and image side surface of the fourth spacer element P4 are in partial contact with the image side surface S8 of the fourth lens and the object side surface S9 of the fifth lens, respectively. The object side surface and image side surface of the fifth spacer element P5 are in partial contact with the image side surface S10 of the fifth lens and the object side surface S11 of the sixth lens, respectively. The object side surface and image side surface of the sixth spacer element P6 are in partial contact with the image side surface S12 of the sixth lens and the object side surface S13 of the seventh lens, respectively. The object side surface and image side surface of the seventh spacer element P7 are in partial contact with the image side surface S14 of the seventh lens and the object side surface S15 of the eighth lens, respectively. The object-side surface of the eighth spacer element P8 is in partial contact with the image-side surface S16 of the eighth lens.

[0116] like Fig. 9As shown, it is a schematic diagram of the structure of the optical imaging system of Example 2-2. In this example, the image side of the third spacer element P3 is also provided with a third auxiliary spacer element P3b and a third auxiliary spacer element P3c in sequence, and the image side of the fifth spacer element P5 is also provided with a fifth auxiliary spacer element P5b. The image side surface of the third spacer element P3 is in partial contact with the object side surface of the third auxiliary spacer element P3b, the image side surface of the third auxiliary spacer element P3b is in partial contact with the object side surface of the third auxiliary spacer element P3c, and the image side surface of the third auxiliary spacer element P3c is in partial contact with the object side surface S7 of the fourth lens. The image side surface of the fifth spacer element P5 is in partial contact with the object side surface of the fifth auxiliary spacer element P5b, and the image side surface of the fifth auxiliary spacer element P5b is in partial contact with the object side surface S11 of the sixth lens. In addition, the bearing and abutting mode of the remaining spacer elements is the same as that of Example 2-1, and the relevant description in Example 2-1 can be referred to, which will not be repeated here.

[0117] like Fig.10 As shown, it is a schematic diagram of the structure of the optical imaging system of Example 2-3. In this example, the image side of the fifth auxiliary spacer element P5b is also provided with a fifth auxiliary spacer element P5c, and the image side of the seventh spacer element P7 is also provided with a seventh auxiliary spacer element P7b. At this time, the image side surface of the fifth auxiliary spacer element P5b is partially in contact with the object side surface of the fifth auxiliary spacer element P5c, and the image side surface of the fifth auxiliary spacer element P5c is partially in contact with the object side surface S11 of the sixth lens. The image side surface of the seventh spacer element P7 is partially in contact with the object side surface of the seventh auxiliary spacer element P7b, and the image side surface of the seventh auxiliary spacer element P7b is partially in contact with the object side surface S15 of the eighth lens. In addition, the bearing and abutting mode of the remaining spacer elements is the same as that of Example 2-2, and the relevant description in Example 2-2 can be referred to, which will not be repeated here.

[0118] In summary, the structural parameters of the optical imaging system of the second embodiment in Embodiment 2-1, Embodiment 2-2, and Embodiment 2-3 are shown in Table 5 (unit: mm).

[0119] Table 5

[0120] Parameters / Examples 2-1 2-2 2-3 D1s 4.723 4.763 4.743 d2m 4.100 4.180 4.080 d3m 4.257 3.878 3.834 d4m 4.391 4.491 4.591 d6s 6.278 6.078 6.178 d6m 6.234 6.034 6.134 D6s 7.797 7.697 7.897 d7m 7.247 7.147 6.582 CP1 0.020 0.021 0.022 EP12 0.297 0.307 0.287 CP4 0.021 0.022 0.020 CP5 0.813 0.021 0.022 EP56 0.780 1.571 1.561 EP67 0.374 0.373 0.363 CP5b 0.791 0.769

[0121] In the second embodiment, the object side surface S1 of the first lens is a convex surface, and the image side surface S2 of the first lens is a concave surface. The object side surface S3 of the second lens is a convex surface, and the image side surface S4 of the second lens is a concave surface. The object side surface S5 of the third lens is a convex surface, and the image side surface S6 of the third lens is a concave surface. The object side surface S7 of the fourth lens is a convex surface, and the image side surface S8 of the fourth lens is a concave surface. The object side surface S9 of the fifth lens is a convex surface, and the image side surface S10 of the fifth lens is a convex surface. The object side surface S11 of the sixth lens is a convex surface, and the image side surface S12 of the sixth lens is a concave surface. The object side surface S13 of the seventh lens is a convex surface, and the image side surface S14 of the seventh lens is a concave surface. The object side surface S15 of the eighth lens is a concave surface, and the image side surface S16 of the eighth lens is a concave surface.

[0122] In Example 2, the effective focal length f of the optical imaging system is 4.95 mm, the effective focal length f1 of the first lens is -34.43 mm, the effective focal length f2 of the second lens is -139.11 mm, the effective focal length f3 of the third lens is 8.48 mm, the effective focal length f4 of the fourth lens is -18.91 mm, the effective focal length f5 of the fifth lens is 4.04 mm, the effective focal length f6 of the sixth lens is -16.03 mm, the effective focal length f7 of the seventh lens is 18.26 mm, the effective focal length f8 of the eighth lens is -5.51 mm, the axial distance SAG12 between the intersection of the image side surface of the first lens and the optical axis to the vertex of the effective radius of the image side surface of the first lens is 0.37 mm, and the axial distance SAG42 between the intersection of the image side surface of the fourth lens and the optical axis to the vertex of the effective radius of the image side surface of the fourth lens is 0.26 mm.

[0123] Table 6 shows a basic structural parameter table of the optical imaging system of Example 2, wherein the units of the radius of curvature and thickness / distance are all millimeters.

[0124] Table 6

[0125]

[0126] Table 7 below lists the high-order coefficients A4, A6, A8, A10, A12, A14, A16 and A18 that can be used for the aspheric mirror surfaces S1-S16 in Example 2. The surface shape of each aspheric lens is defined according to formula (1) in Example 1.

[0127] Table 7

[0128]

[0129]

[0130] Fig.11The axial chromatic aberration curve of the optical imaging system of the second embodiment is shown, which indicates the deviation of the focusing point of light of different wavelengths after passing through the light imaging system. Fig.12 The astigmatism curve of the optical imaging system of the second embodiment is shown, which represents the meridional image plane curvature and the sagittal image plane curvature. Fig.13 The magnification chromatic aberration curve of the optical imaging system of the second embodiment is shown, which represents the deviation of different image heights on the imaging surface after the light passes through the optical imaging system.

[0131] according to Figures 11 to 13 It can be seen that the optical imaging system provided in the second embodiment can achieve good imaging quality.

[0132] Embodiment 3

[0133] like Figures 14 to 19 As shown, the optical imaging system of embodiment 3 is described. Fig.14 A schematic diagram of the structure of the optical imaging system of Example 3-1 is shown, Fig.15 A schematic diagram of the structure of the optical imaging system of Example 3-2 is shown, Fig.16 A schematic structural diagram of the optical imaging system of Example 3-3 is shown.

[0134] like Figures 14 to 16 As shown, the optical imaging system includes a lens barrel P0 and a first lens E1, a first spacing element P1, a second lens E2, a second spacing element P2, a third lens E3, a third spacing element P3, a fourth lens E4, a fourth spacing element P4, a fifth lens E5, a fifth spacing element P5, a fifth auxiliary spacing element P5b, a sixth lens E6, a sixth spacing element P6, a seventh lens E7, a seventh spacing element P7, an eighth lens E8, and an eighth spacing element P8, which are arranged in sequence in the lens barrel P0 from the object side to the image side along the optical axis.

[0135] like Fig.14As shown, it is a structural schematic diagram of the optical imaging system of Example 3-1. In this example, the object side surface and image side surface of the first spacer element P1 are in partial contact with the image side surface S2 of the first lens and the object side surface S3 of the second lens, respectively. The object side surface and image side surface of the second spacer element P2 are in partial contact with the image side surface S4 of the second lens and the object side surface S5 of the third lens, respectively. The object side surface and image side surface of the third spacer element P3 are in partial contact with the image side surface S6 of the third lens and the object side surface S7 of the fourth lens, respectively. The object side surface and image side surface of the fourth spacer element P4 are in partial contact with the image side surface S8 of the fourth lens and the object side surface S9 of the fifth lens, respectively. The object side surface and image side surface of the fifth spacer element P5 are in partial contact with the image side surface S10 of the fifth lens and the object side surface of the fifth auxiliary spacer element P5b, respectively, and the image side surface of the fifth auxiliary spacer element P5b is in partial contact with the object side surface S11 of the sixth lens. The object side surface and image side surface of the sixth spacer element P6 are in partial contact with the image side surface S12 of the sixth lens and the object side surface S13 of the seventh lens, respectively. The object-side surface and image-side surface of the seventh spacer element P7 partially contact the image-side surface S14 of the seventh lens and the object-side surface S15 of the eighth lens, respectively. The object-side surface of the eighth spacer element P8 partially contacts the image-side surface S16 of the eighth lens.

[0136] like Fig.15 FIG. 3 is a schematic diagram of the structure of the optical imaging system of Example 3-2. In this example, the supporting and abutting manner of each spacing element is the same as that of Example 3-1, and the relevant description in Example 3-1 may be referred to, and will not be repeated here.

[0137] like Fig.16 , which is a schematic diagram of the structure of the optical imaging system of Example 3-3. In this example, a fifth auxiliary spacer element P5c is also provided on the image side of the fifth auxiliary spacer element P5b. At this time, the image side surface of the fifth auxiliary spacer element P5b is partially in contact with the object side surface of the fifth auxiliary spacer element P5c, and the image side surface of the fifth auxiliary spacer element P5c is partially in contact with the object side surface S11 of the sixth lens. In addition, the supporting and abutting manner of the remaining spacer elements is the same as that of Example 3-1, and the relevant description in Example 3-1 may be referred to, and no further description is given here.

[0138] In summary, the structural parameters of the optical imaging system of Example 3 in Example 3-1, Example 3-2, and Example 3-3 are shown in Table 8 (unit: mm).

[0139] Table 8

[0140] Parameters / Examples 3-1 3-2 3-3 D1s 5.585 6.610 6.710 d2m 4.159 3.747 3.847 d3m 3.839 3.739 3.939 d4m 4.626 4.526 4.726 d6s 6.588 6.688 6.788 d6m 6.588 6.688 6.788 D6s 9.600 9.700 9.800 d7m 6.338 6.438 6.538 CP1 0.020 0.021 0.022 EP12 0.504 0.428 0.438 CP4 0.020 0.021 0.022 CP5 0.020 0.021 0.022 EP56 1.183 1.173 1.163 EP67 0.805 0.795 0.785 CP5b 0.516 0.516 0.505

[0141] In Embodiment 3, the object side surface S1 of the first lens is a convex surface, and the image side surface S2 of the first lens is a concave surface. The object side surface S3 of the second lens is a convex surface, and the image side surface S4 of the second lens is a concave surface. The object side surface S5 of the third lens is a convex surface, and the image side surface S6 of the third lens is a convex surface. The object side surface S7 of the fourth lens is a convex surface, and the image side surface S8 of the fourth lens is a concave surface. The object side surface S9 of the fifth lens is a convex surface, and the image side surface S10 of the fifth lens is a convex surface. The object side surface S11 of the sixth lens is a convex surface, and the image side surface S12 of the sixth lens is a concave surface. The object side surface S13 of the seventh lens is a convex surface, and the image side surface S14 of the seventh lens is a convex surface. The object side surface S15 of the eighth lens is a convex surface, and the image side surface S16 of the eighth lens is a concave surface.

[0142] In Example 3, the effective focal length f of the optical imaging system is 5.44 mm, the effective focal length f1 of the first lens is -102.96 mm, the effective focal length f2 of the second lens is -42.97 mm, the effective focal length f3 of the third lens is 6.31 mm, the effective focal length f4 of the fourth lens is -9.13 mm, the effective focal length f5 of the fifth lens is 5.34 mm, the effective focal length f6 of the sixth lens is -28.91 mm, the effective focal length f7 of the seventh lens is 9.68 mm, the effective focal length f8 of the eighth lens is -5.53 mm, the axial distance SAG12 from the intersection of the image side surface of the first lens and the optical axis to the vertex of the effective radius of the image side surface of the first lens is 0.42 mm, and the axial distance SAG42 from the intersection of the image side surface of the fourth lens and the optical axis to the vertex of the effective radius of the image side surface of the fourth lens is 0.36 mm.

[0143] Table 9 shows a basic structural parameter table of the optical imaging system of Example 3, wherein the units of the radius of curvature and thickness / distance are all millimeters.

[0144] Table 9

[0145]

[0146] Table 10 below lists the high-order coefficients A4, A6, A8, A10, A12, A14, A16 and A18 that can be used for each aspheric mirror surface S1-S16 in Example 3. The surface shape of each aspheric lens is defined according to formula (1) in Example 1.

[0147] Table 10

[0148] Face number A4 A6 A8 A10 A12 A14 A16 A18 S1 -1.0105E-02 -2.8920E-03 -9.2176E-03 1.2112E-02 -7.8934E-03 2.9708E-03 -6.5393E-04 7.8572E-05 S2 -7.2427E-04 -2.0445E-02 2.7300E-04 8.6742E-03 -6.7530E-03 2.2326E-03 -3.2654E-04 1.4155E-05 S3 -8.8107E-03 -1.6743E-03 -1.1730E-02 1.5128E-02 -8.3285E-03 2.0115E-03 -1.0859E-04 -3.2605E-05 S4 -6.2006E-02 3.5061E-02 -9.2042E-02 1.0222E-01 -5.9492E-02 2.0307E-02 -4.0942E-03 4.5125E-04 S5 -2.8592E-02 3.5532E-02 -9.6582E-02 1.0210E-01 -5.8141E-02 1.9726E-02 -3.9702E-03 4.3644E-04 S6 5.9789E-02 -3.6533E-02 2.6926E-02 -1.7616E-02 6.1138E-03 -8.4157E-04 -4.3604E-05 2.3281E-05 S7 -1.4338E-02 -1.7965E-02 2.1519E-02 -1.3561E-02 4.1005E-03 -2.2719E-04 -1.7784E-04 4.2703E-05 S8 -5.3636E-02 1.3701E-02 -2.8475E-03 -1.4217E-03 1.3951E-03 -4.4122E-04 5.6154E-05 -4.5301E-07 S9 1.8265E-02 -2.1906E-03 -4.1758E-03 4.4621E-03 -2.9897E-03 1.2868E-03 -3.3488E-04 4.7414E-05 S10 2.2480E-02 -8.3924E-03 -6.3800E-04 3.9843E-03 -2.8842E-03 1.0710E-03 -2.2520E-04 2.5301E-05 S11 -1.7730E-02 9.2822E-04 -1.1453E-03 7.5426E-04 -2.9689E-04 7.1197E-05 -9.7248E-06 6.9019E-07 S12 -3.6612E-02 1.4481E-02 -8.4118E-03 3.5018E-03 -1.0200E-03 1.9426E-04 -2.2087E-05 1.3432E-06 S13 3.3908E-03 2.7965E-03 -3.3788E-03 1.7309E-03 -5.1145E-04 8.3830E-05 -7.5313E-06 3.4787E-07 S14 -2.6378E-03 6.0393E-03 -4.0755E-03 1.8375E-03 -4.8317E-04 7.3056E-05 -6.3310E-06 2.9369E-07 S15 -8.6333E-02 1.7746E-02 -2.8877E-03 1.9803E-04 9.4845E-05 -2.8270E-05 3.2644E-06 -1.7797E-07 S16 -8.1465E-02 2.2739E-02 -5.2592E-03 8.8723E-04 -1.0074E-04 7.4327E-06 -3.4015E-07 8.7530E-09

[0149] Fig.17 The axial chromatic aberration curve of the optical imaging system of the third embodiment is shown, which indicates the deviation of the focal point of light of different wavelengths after passing through the light imaging system. Fig.18The astigmatism curve of the optical imaging system of the third embodiment is shown, which represents the meridional image plane curvature and the sagittal image plane curvature. Fig.19 The magnification chromatic aberration curve of the optical imaging system of the third embodiment is shown, which represents the deviation of different image heights on the imaging surface after the light passes through the optical imaging system.

[0150] according to Figures 17 to 19 It can be seen that the optical imaging system provided in the third embodiment can achieve good imaging quality.

[0151] In summary, Embodiment 1 to Embodiment 3 respectively satisfy the relationship shown in Table 11.

[0152] Table 11

[0153] Conditional / Example 1-1 1-2 1-3 2-1 2-2 2-3 3-1 3-2 3-3 T45 / CP4 20.94 19.94 19.03 4.76 4.55 5.00 12.39 11.80 11.26 d4m / CT5 4.76 4.71 4.61 3.25 3.33 3.40 3.98 3.89 4.06 SAG42 / CP4 22.00 20.95 20.00 12.38 11.82 13.00 18.00 17.14 16.36 f4 / R7 -2.17 -2.17 -2.17 -4.81 -4.81 -4.81 -1.66 -1.66 -1.66 f4 / d3m -2.37 -2.39 -2.33 -4.44 -4.88 -4.93 -2.38 -2.44 -2.32 EP67 / (T78-T67) 2.44 2.48 2.49 0.51 0.51 0.49 3.06 3.02 2.98 d7m / T78 5.49 5.45 5.70 5.97 5.89 5.42 8.12 8.25 8.37 D1s / R2 1.75 2.11 2.11 1.70 1.72 1.71 2.24 2.65 2.69 R1 / CT1 7.27 7.27 7.27 9.44 9.44 9.44 6.90 6.90 6.90 SAG12 / CP1 23.00 21.90 20.91 18.50 17.62 16.82 21.00 20.00 19.09 EP12 / T23 6.70 6.90 7.14 4.24 4.39 4.10 7.17 6.09 6.23 d2m / CT3 7.60 7.52 7.70 7.33 7.47 7.29 9.15 8.24 8.46 f3 / d2m 1.19 1.20 1.17 2.07 2.03 2.08 1.52 1.68 1.64 (CP5+CP5b) / CT6 3.07 2.32 2.26 0.89 0.90 0.88 EP56 / CT6 1.52 1.81 4.53 2.23 4.49 4.46 1.97 1.96 1.94 f5 / (CT5+CP5) 2.56 2.56 5.26 1.87 2.95 2.95 4.51 4.51 4.50 d6s / CT6 16.93 16.81 17.22 17.94 17.37 17.65 10.98 11.15 11.31 f6 / D6s -2.00 -2.02 -2.01 -2.06 -2.08 -2.03 -3.01 -2.98 -2.95 CT7 / EP67 1.43 1.40 1.40 1.61 1.62 1.66 0.88 0.89 0.90 f7 / d6m 1.43 1.44 1.41 2.93 3.03 2.98 1.47 1.45 1.43 T78 / CT8 3.40 3.40 3.40 2.02 2.02 2.02 1.12 1.12 1.12 d7m / (T78+CT8) 4.24 4.21 4.41 3.99 3.94 3.63 4.28 4.35 4.42 f4 / CT5 4.99 4.99 4.99 6.29 6.29 6.29 5.42 5.42 5.42 d4m / (CP4+T45) 10.57 10.45 10.2 36.29 36.81 38.26 17.28 16.84 17.52

[0154] Table 12 shows the effective focal length of the optical imaging system of Embodiments 1 to 3, the effective focal length of each lens, and the SAG parameters.

[0155] Table 12

[0156]

[0157]

[0158] The present application also provides an imaging device, whose electronic photosensitive element can be a photosensitive 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 in a mobile electronic device such as a mobile phone. The imaging device is equipped with the optical imaging system described above.

[0159] Obviously, the above-described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work should fall within the scope of protection of the present invention.

[0160] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit the exemplary embodiments according to the present application. As used herein, unless the context clearly indicates otherwise, the singular form is also intended to include the plural form. In addition, it should be understood that when the terms "comprise" and / or "include" are used in this specification, it indicates the presence of features, steps, operations, devices, components and / or combinations thereof.

[0161] It should be noted that the terms "first", "second", etc. in the specification and claims of the present application and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. It should be understood that the numbers used in this way can be interchanged where appropriate, so that the embodiments of the present application described herein can be implemented in an order other than those illustrated or described herein.

[0162] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. An optical imaging system, characterized in that: It includes a lens barrel, a lens group and a spacer element group arranged in the lens barrel. The lens group is composed of eight lenses. The eight lenses are, in order from the object side to the image side, a first lens with a positive or negative optical power, a second lens with a negative optical power, a third lens with a positive optical power, a fourth lens with a negative optical power, a fifth lens with a positive optical power, a sixth lens with a negative optical power, a seventh lens with a positive optical power, and an eighth lens with a negative optical power. Among the first lens to the eighth lens, the fifth lens has the largest central thickness on the optical axis of the optical imaging system. The spacer element group includes a first spacer element placed between the first lens and the second lens and in partial contact with the image side surface of the first lens, a second spacer element placed between the second lens and the third lens and in partial contact with the image side surface of the second lens, a third spacer element placed between the third lens and the fourth lens and in partial contact with the image side surface of the third lens, a fourth spacer element placed between the fourth lens and the fifth lens and in partial contact with the image side surface of the fourth lens, a fifth spacer element placed between the fifth lens and the sixth lens and in partial contact with the image side surface of the fifth lens, a sixth spacer element placed between the sixth lens and the seventh lens and in partial contact with the image side surface of the sixth lens, and a seventh spacer element placed between the seventh lens and the eighth lens and in partial contact with the image side surface of the seventh lens. Among them, the air gap T45 between the fourth lens and the fifth lens on the optical axis and the maximum axial thickness CP4 of the fourth spacer element satisfy: 4.50 < T45 / CP4 < 20.98; the inner diameter d4m of the image side surface of the fourth spacer element and the central thickness CT5 of the fifth lens on the optical axis satisfy: 3.21 < d4m / CT5 < 4.

81.

2. The optical imaging system according to claim 1, characterized in that: The effective focal length f4 of the fourth lens and the curvature radius R7 of the object side surface of the fourth lens satisfy: -4.85 < f4 / R7 < -1.62; the effective focal length f4 of the fourth lens and the inner diameter d3m of the image side surface of the third spacer element satisfy: -4.98 < f4 / d3m < -2.

27.

3. The optical imaging system according to claim 1, characterized in that: The air gap T67 between the sixth lens and the seventh lens on the optical axis, the air gap T78 between the seventh lens and the eighth lens on the optical axis, and the spacer distance EP67 on the optical axis from the image side surface of the sixth spacer element to the object side surface of the seventh spacer element satisfy: 0.44 < EP67 / (T78 - T67) < 3.

11.

4. The optical imaging system according to claim 1, characterized in that: Among the adjacent two lenses of the first lens to the eighth lens, the air gap between the seventh lens and the eighth lens on the optical axis is the largest. The inner diameter d7m of the image side surface of the seventh spacer element and the air gap T78 between the seventh lens and the eighth lens on the optical axis satisfy: 5.37 < d7m / T78 < 8.

42.

5. The optical imaging system according to claim 1, characterized in that: The following conditions are satisfied between the outer diameter D1s of the object side of the first spacer element and the radius of curvature R2 of the image side of the first lens: 1.65 < D1s / R2 < 2.74; the following condition is satisfied between the radius of curvature R1 of the object side of the first lens and the central thickness CT1 of the first lens on the optical axis: 6.85 < R1 / CT1 < 9.

49.

6. The optical imaging system according to claim 1, characterized in that: The following condition is satisfied between the axial distance EP12 on the optical axis from the image side of the first spacer element to the object side of the second spacer element and the air gap T23 on the optical axis between the second lens and the third lens: 4.05 < EP12 / T23 < 7.

21.

7. The optical imaging system according to claim 1, characterized in that: The following condition is satisfied between the inner diameter d2m of the image side of the second spacer element and the central thickness CT3 of the third lens on the optical axis: 7.24 < d2m / CT3 < 9.20; the following condition is satisfied between the effective focal length f3 of the third lens and the inner diameter d2m of the image side of the second spacer element: 1.12 < f3 / d2m < 2.

13.

8. The optical imaging system according to claim 1, characterized in that: The following condition is satisfied between the axial distance EP56 on the optical axis from the image side of the fifth spacer element to the object side of the sixth spacer element and the central thickness CT6 of the sixth lens on the optical axis: 1.47 < EP56 / CT6 < 4.

58.

9. The optical imaging system according to claim 1, characterized in that: The following condition is satisfied among the effective focal length f5 of the fifth lens, the central thickness CT5 of the fifth lens on the optical axis, and the maximum axial thickness CP5 of the fifth spacer element: 1.82 < f5 / (CT5 + CP5) < 5.

30.

10. The optical imaging system according to claim 1, characterized in that: The following condition is satisfied between the on-axis distance SAG42 from the intersection of the image side of the fourth lens and the optical axis to the effective radius vertex of the image side of the fourth lens and the maximum axial thickness CP4 of the fourth spacer element: 11.71 < SAG42 / CP4 < 22.

19.

11. The optical imaging system according to claim 1, characterized in that: The following condition is satisfied between the inner diameter d6s of the object side of the sixth spacer element and the central thickness CT6 of the sixth lens on the optical axis: 10.93 < d6s / CT6 < 17.99; the following condition is satisfied between the effective focal length f6 of the sixth lens and the outer diameter D6s of the object side of the sixth spacer element: -3.06 < f6 / D6s < -1.

95.

12. The optical imaging system according to claim 1, characterized in that: The following condition is satisfied between the central thickness CT7 of the seventh lens on the optical axis and the axial distance EP67 on the optical axis from the image side of the sixth spacer element to the object side of the seventh spacer element: 0.83 < CT7 / EP67 < 1.71; the following condition is satisfied between the effective focal length f7 of the seventh lens and the inner diameter d6m of the image side of the sixth spacer element: 1.37 < f7 / d6m < 3.

08.

13. The optical imaging system according to claim 1, characterized in that: The following condition is satisfied between the on-axis distance SAG12 from the intersection of the image side of the first lens and the optical axis to the effective radius vertex of the image side of the first lens and the maximum axial thickness CP1 of the first spacer element: 16.65 < SAG12 / CP1 < 23.

19.

14. The optical imaging system according to claim 1, characterized in that: The air gap T78 between the seventh lens and the eighth lens on the optical axis and the central thickness CT8 of the eighth lens on the optical axis satisfy: 1.07 < T78 / CT8 < 3.45; the inner diameter d7m of the image side of the seventh spacer element, the air gap T78 between the seventh lens and the eighth lens on the optical axis and the central thickness CT8 of the eighth lens on the optical axis satisfy: 3.58 < d7m / (T78 + CT8) < 4.

47.

15. The optical imaging system according to any one of claims 1 to 14, characterized in that: The spacer element group further includes an eighth spacer element disposed on the image side of the eighth lens and in partial contact with the image side surface of the eighth lens.

16. The optical imaging system according to any one of claims 1 to 14, characterized in that: The spacer element group further includes a fifth auxiliary spacer element disposed on the image side of the fifth spacer element and in partial contact with the image side surface of the fifth spacer element. The maximum axial thickness CP5 of the fifth spacer element, the maximum axial thickness CP5b of the fifth auxiliary spacer element and the central thickness CT6 of the sixth lens on the optical axis satisfy: 0.82 < (CP5 + CP5b) / CT6 < 3.12.

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