Optical image capturing system

Abstract

The utility model discloses an optical imaging system. The optical imaging system comprises a lens cone, an eight-piece lens group and a separator group, wherein the eight-piece lens group and the separator group are arranged in the lens cone; the eight-piece lens group comprises a first lens with positive focal power, a second lens with positive focal power, a third lens with negative focal power, a fourth lens with negative focal power, a fifth lens with focal power and a sixth lens with positive focal power which are sequentially arranged from the object side to the image side along the optical axis; the seventh lens has positive focal power; the eighth lens has negative focal power; the separator group comprises a seventh separator which is arranged on the image side surface of the seventh lens and is in contact with the image side surface of the seventh lens; wherein the curvature radius R16 of the image side surface of the eighth lens and the inner diameter d7m of the image side surface of the seventh isolation piece meet the following conditions: 1.5 lt; d7m / R16lt; 4.2, 4.2; the effective focal length f8 of the eighth lens, the inner diameter d7m of the image side surface of the seventh isolation piece and the outer diameter D7m of the image side surface of the seventh isolation piece meet the following conditions: 0 lt; (D7m-d7m) / f8lt; and 1.40.

Description

Technical Field

[0001] This application relates to the field of optical devices, and particularly to an optical imaging system including eight lenses. Background Art

[0002] In recent years, with the continuous development of science and technology, users have higher and higher requirements for portable electronic devices such as smart phones, especially in terms of the performance of the optical imaging system. For example, while the optical main parameters of the optical imaging system meet the design requirements, higher requirements are put forward for the assembly stability and stray light quality of the optical imaging system.

[0003] Generally speaking, the increase in the number of lenses can improve the imaging quality of the optical imaging system. However, the increase in the number of lenses will also lead to an increase in the difficulty of the stability of the optical imaging system in the assembly stage and the molding stage, and an increase in the number of ghost images related to the lenses and stray light related to the spacers, seriously affecting the imaging quality of the optical imaging system. Summary of the Utility Model

[0004] This application provides an optical imaging system that can at least solve or partially solve at least one problem or other problems existing in the prior art.

[0005] One aspect of this application provides such an optical imaging system, which includes a lens barrel and an eight-piece lens group and a spacer group placed in the lens barrel; the eight-piece lens group includes a first lens with a positive focal power, a second lens with a positive focal power, a third lens with a negative focal power, a fourth lens with a negative focal power, a fifth lens with a focal power, a sixth lens with a positive focal power, a seventh lens with a positive focal power, and an eighth lens with a negative focal power arranged in sequence from the object side to the image side along the optical axis; the spacer group includes a seventh spacer placed on and in contact with the image side of the seventh lens; wherein, the radius of curvature R16 of the image side of the eighth lens and the inner diameter d7m of the image side of the seventh spacer satisfy: 1.5 < d7m / R16 < 4.2; and the effective focal length f8 of the eighth lens, the inner diameter d7m of the image side of the seventh spacer, and the outer diameter D7m of the image side of the seventh spacer satisfy: 0 < (D7m - d7m) / |f8| < 1.40.

[0006] According to an exemplary embodiment of this application, the radius of curvature R16 of the image side of the eighth lens, the inner diameter d7s of the object side of the seventh spacer, and the outer diameter D7s of the object side of the seventh spacer satisfy: 0 ≤ (D7s - d7s) / R16 ≤ 2.5.

[0007] According to an exemplary embodiment of the present application, the maximum length L of the lens barrel along the direction of the optical axis, the maximum value CTmax of the center thickness of each lens of the first lens to the eighth lens on the optical axis, and the maximum value ATmax of the air interval between two adjacent lenses of the first lens to the eighth lens on the optical axis satisfy: 3.90 <L / (CTmax+ATmax)<5.00。

[0008] According to an exemplary embodiment of the present application, the effective focal length f8 of the eighth lens, the refractive index N8 of the eighth lens, the outer diameter D0s of the object side end surface of the lens barrel and the outer diameter D0m of the image side end surface of the lens barrel satisfy: -2.00 <f8×N8 / (D0m-D0s)<-1.00。

[0009] According to an exemplary embodiment of the present application, the inner diameter d0s of the object side end surface of the lens barrel, the inner diameter d0m of the image side end surface of the lens barrel and the total effective focal length f of the optical imaging system satisfy: 1.00<(d0m-d0s) / f<1.60.

[0010] According to an exemplary embodiment of the present application, the spacer group further includes a first spacer disposed on the image side surface of the first lens and in contact with the image side surface of the first lens, wherein the interval EP01 between the object side end surface of the lens barrel and the first spacer along the optical axis, the outer diameter D1s of the object side surface of the first spacer, the center thickness CT1 of the first lens on the optical axis and the maximum effective semi-aperture DT12 of the image side surface of the first lens satisfy: 4.50 <EP01 / CT1+D1s / DT12<6.00。

[0011] According to an exemplary embodiment of the present application, the spacer group further includes a second spacer disposed on the image side of the second lens and in contact with the image side of the second lens, wherein the combined focal length f23 of the second lens and the third lens and the outer diameter D2s of the object side of the second spacer satisfy: -11 <f23 / D2s<11。

[0012] According to an exemplary embodiment of the present application, the isolation member group also includes a second isolation member placed on the image side surface of the second lens and in contact with the image side surface of the second lens, and a third isolation member placed on the image side surface of the third lens and in contact with the image side surface of the third lens, wherein the combined focal length f23 of the second lens and the third lens, the outer diameter D2s of the object side surface of the second isolation member, and the outer diameter D3s of the object side surface of the third isolation member satisfy: -0.30<(D2s+D3s) / f23<0.30.

[0013] According to an exemplary embodiment of the present application, the spacer group further includes a fourth spacer disposed on and in contact with the image side surface of the fourth lens and a fifth spacer disposed on and in contact with the image side surface of the fifth lens. Wherein, the central thickness CT5 of the fifth lens on the optical axis and the maximum thickness CP5 of the fifth spacer along the optical axis direction satisfy: 0 < CP5 / CT5 < 1; the interval EP45 between the fourth spacer and the fifth spacer along the optical axis, the inner diameter d5m of the image side surface of the fifth spacer and the outer diameter D5m of the image side surface of the fifth spacer satisfy: 1.50 < (D5m - d5m) / EP45 < 10.00.

[0014] According to an exemplary embodiment of the present application, the spacer group further includes a fourth spacer disposed on and in contact with the image side surface of the fourth lens and a fifth spacer disposed on and in contact with the image side surface of the fifth lens. Wherein, the interval EP45 between the fourth spacer and the fifth spacer along the optical axis and the axial distance SAGH51 from the intersection of the object side surface of the fifth lens and the optical axis to the vertex of the maximum effective semi-aperture of the object side surface of the fifth lens satisfy: 1.50 < EP45 / SAGH51 < 5.30.

[0015] According to an exemplary embodiment of the present application, the spacer group further includes a fifth spacer disposed on and in contact with the image side surface of the fifth lens. Wherein, the inner diameter d5s of the object side surface of the fifth spacer and the combined focal length f56 of the fifth lens and the sixth lens satisfy: 1.20 < d5s / f56 < 1.50.

[0016] According to an exemplary embodiment of the present application, the spacer group further includes a fifth spacer disposed on and in contact with the image side surface of the fifth lens and a sixth spacer disposed on and in contact with the image side surface of the sixth lens. Wherein, the interval EP56 between the fifth spacer and the sixth spacer along the optical axis, the interval EP67 between the sixth spacer and the seventh spacer along the optical axis, the central thickness CT6 of the sixth lens on the optical axis and the central thickness CT7 of the seventh lens on the optical axis satisfy: 0.30 < (EP56 + EP67) / (CT6 + CT7) < 1.20.

[0017] According to an exemplary embodiment of the present application, the spacer group further includes a fifth spacer disposed on and in contact with the image side surface of the fifth lens and a sixth spacer disposed on and in contact with the image side surface of the sixth lens. Wherein, the interval EP56 between the fifth spacer and the sixth spacer along the optical axis and the axial distance SAGH52 from the intersection of the image side surface of the fifth lens and the optical axis to the vertex of the maximum effective semi-aperture of the image side surface of the fifth lens satisfy: 0.50 < EP56 / SAGH52 < 4.10.

[0018] According to an exemplary embodiment of the present application, the spacer group further includes a sixth spacer disposed on the image side of the sixth lens and in contact with the image side of the sixth lens, wherein the interval EP67 between the sixth spacer and the seventh spacer along the optical axis and the air interval T67 between the sixth lens and the seventh lens on the optical axis satisfy: 0.60 <EP67 / T67<4.00。

[0019] According to an exemplary embodiment of the present application, the isolation member group also includes a sixth isolation member disposed on the image side surface of the sixth lens and in contact with the image side surface of the sixth lens, wherein the effective focal length f7 of the seventh lens, the curvature radius R13 of the object side surface of the seventh lens, the curvature radius R14 of the image side surface of the seventh lens and the outer diameter D6s of the object side surface of the sixth isolation member satisfy: 0.15<|R13 / R14|×(D6s / f7)<1.20.

[0020] The optical imaging system provided by the present application uses eight lenses. By controlling the ratio of the difference between the outer and inner diameters of the image side surface of the seventh spacer and the effective focal length of the eighth lens, the effective focal length of the eighth lens can be constrained within a reasonable range, thereby reducing the sensitivity of the optical imaging system. In addition, since the light passing through the eighth lens is steeper and the inner diameter of the image side surface of the seventh spacer is too large, stray light will be generated. Therefore, by constraining the curvature radius of the image side surface of the eighth lens, it can be ensured that the light passing through the effective aperture of the edge of the eighth lens is smoothly refracted to the image surface. At the same time, by limiting the inner diameter of the image side surface of the seventh spacer to be within a reasonable range, the stray light reflected from the effective aperture of the edge of the seventh lens and the eighth lens can be effectively blocked, thereby improving the imaging quality of the optical imaging system. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Other features, objects and advantages of the present application will become more apparent by reading the detailed description of non-limiting embodiments made with reference to the following drawings, in which:

[0022] Figure 1 shows a parameter annotation diagram of an optical imaging system according to the present application;

[0023] Figure 2A A stray light simulation diagram is shown when the optical imaging system according to the present application satisfies d7m / R16=1.98 and (D7m-d7m) / |f8|=1.28;

[0024] Figure 2B A stray light simulation diagram is shown when the optical imaging system according to the present application satisfies d7m / R16=1.17, (D7m-d7m) / |f8|=1.53;

[0025] Figure 3 A schematic structural diagram of an optical imaging system according to Embodiment 1 of the present application is shown;

[0026] Figure 4 A schematic structural diagram of an optical imaging system according to Embodiment 2 of the present application is shown;

[0027] Figure 5 A schematic structural diagram of an optical imaging system according to Embodiment 3 of the present application is shown;

[0028] FIG. 6A to FIG. 6D The axial chromatic aberration curve, the astigmatism curve, the distortion curve and the magnification chromatic aberration curve of the optical imaging system according to Embodiment 1, 2 or 3 of the present application are respectively shown;

[0029] Figure 7 A schematic structural diagram of an optical imaging system according to Embodiment 4 of the present application is shown;

[0030] Figure 8 A schematic structural diagram of an optical imaging system according to Embodiment 5 of the present application is shown;

[0031] Fig. 9 A schematic structural diagram of an optical imaging system according to Embodiment 6 of the present application is shown;

[0032] FIG. 10A to FIG. 10D The axial chromatic aberration curve, the astigmatism curve, the distortion curve and the magnification chromatic aberration curve of the optical imaging system according to Embodiment 4, 5 or 6 of the present application are respectively shown;

[0033] Fig.11 A schematic structural diagram of an optical imaging system according to Embodiment 7 of the present application is shown;

[0034] Fig.12 A schematic structural diagram of an optical imaging system according to Embodiment 8 of the present application is shown;

[0035] Fig.13 A schematic diagram of the structure of an optical imaging system according to Embodiment 9 of the present application is shown; and

[0036] FIG. 14A to FIG. 14D The axial chromatic aberration curve, astigmatism curve, distortion curve and magnification chromatic aberration curve of the optical imaging system according to Embodiment 7, 8 or 9 of the present application are respectively shown. DETAILED DESCRIPTION

[0037] In order to better understand the present application, a more detailed description will be made of various aspects of the present application with reference to the accompanying drawings. It should be understood that these detailed descriptions are only descriptions of exemplary embodiments of the present application, and do not limit the scope of the present application in any way. Throughout the specification, the same figure numerals refer to the same elements.

[0038] 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.

[0039] 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.

[0040] In this article, the paraxial region refers to the region near the optical axis. If the lens surface is convex and the position of the convex surface is not defined, it means that the lens surface is convex at least in the paraxial region; if the lens surface is concave and the position of the concave surface is not defined, it means that the lens surface is concave at least in the paraxial region. The surface of each lens closest to the object is called the object side of the lens, and the surface of each lens closest to the imaging plane is called the image side of the lens.

[0041] It should also be understood that the terms "including" and / or "having", when used in this specification, indicate the presence of the stated features, elements and / or components, but do not exclude the presence or addition of one or more other features, elements, components and / or combinations thereof. In addition, when describing the embodiments of the present application, the term "may" is used to mean "one or more embodiments of the present application". And, the term "exemplary" is intended to refer to an example or illustration.

[0042] Unless otherwise defined, all terms (including technical terms and scientific terms) used in this article have the same meaning as those commonly understood by ordinary technicians in the field to which this application belongs. It should also be understood that terms (such as terms defined in commonly used dictionaries) should be interpreted as having the same meaning as their meaning in the context of the relevant technology, and will not be interpreted in an idealized or overly formal sense unless explicitly defined in this article.

[0043] 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 application will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

[0044] Figure 1 Schematic diagram of the structural arrangement and some parameters of the optical imaging system according to an exemplary embodiment of the present application. Figure 1, D1s represents the outer diameter of the object side surface of the first isolator, D2s represents the outer diameter of the object side surface of the second isolator, D3s represents the outer diameter of the object side surface of the third isolator, d5s represents the inner diameter of the object side surface of the fifth isolator, d5m represents the inner diameter of the image side surface of the fifth isolator, D5m represents the outer diameter of the image side surface of the fifth isolator, D6s represents the outer diameter of the object side surface of the sixth isolator, d7s represents the inner diameter of the object side surface of the seventh isolator, d7m represents the inner diameter of the image side surface of the seventh isolator, D7s represents the outer diameter of the object side surface of the seventh isolator, D7m represents the outer diameter of the image side surface of the seventh isolator, d 0s represents the inner diameter of the object side end face of the lens barrel, d0m represents the inner diameter of the image side end face of the lens barrel, D0s represents the outer diameter of the object side end face of the lens barrel, D0m represents the outer diameter of the image side end face of the lens barrel, EP01 represents the interval between the object side end face of the lens barrel and the first spacer along the optical axis, EP45 represents the interval between the fourth spacer and the fifth spacer along the optical axis, CP5 represents the maximum thickness of the fifth spacer along the optical axis, EP56 represents the interval between the fifth spacer and the sixth spacer along the optical axis, EP67 represents the interval between the sixth spacer and the seventh spacer along the optical axis, and L represents the maximum length of the lens barrel along the direction of the optical axis.

[0045] refer to Figures 3 to 5 , Figures 7 to 9 as well as Figures 11 to 13 In a first aspect of the present application, an optical imaging system is provided. The optical imaging system may include an eight-piece lens group, and the eight-piece lens group may include a first lens, a second lens, a third lens, a fourth lens, a fifth lens, a sixth lens, a seventh lens, and an eighth lens arranged in sequence from the object side to the image side along the optical axis. Among the first lens to the eighth lens, any two adjacent lenses may have an air gap between them.

[0046] In an exemplary embodiment, the first lens may have positive power. The second lens may have positive power. The third lens may have negative power. The fourth lens may have negative power. The fifth lens may have positive power or negative power. The sixth lens may have positive power. The seventh lens may have positive power. The eighth lens may have negative power.

[0047] In example embodiments, the object-side surface of the first lens may be a convex surface, and the image-side surface may be a concave surface.

[0048] In example embodiments, the object-side surface of the second lens may be a convex surface, and the image-side surface may be a convex surface or a concave surface.

[0049] In example embodiments, the object-side surface of the third lens may be a concave surface, and the image-side surface may be a concave surface.

[0050] In exemplary embodiments, the object-side surface of the fourth lens may be a convex surface or a concave surface, and the image-side surface may be a convex surface or a concave surface.

[0051] In example embodiments, the object-side surface of the fifth lens may be a convex surface or a concave surface, and the image-side surface may be a concave surface.

[0052] In example embodiments, the object-side surface of the sixth lens may be a convex surface, and the image-side surface may be a convex surface.

[0053] In example embodiments, the object-side surface of the seventh lens may be a concave surface, and the image-side surface may be a convex surface.

[0054] In example embodiments, the object-side surface of the eighth lens may be a convex surface or a concave surface, and the image-side surface may be a concave surface.

[0055] In an exemplary embodiment, the optical imaging system may further include a stop disposed between the object side and the first lens.

[0056] In an exemplary embodiment, the optical imaging system may further include an isolator group, which may include one or more of a first isolator, a second isolator, a third isolator, a fourth isolator, a fifth isolator, a sixth isolator, and a seventh isolator. The first isolator may be placed on the image side of the first lens and at least partially contact the image side of the first lens. The second isolator may be placed on the image side of the second lens and at least partially contact the image side of the second lens. The third isolator may be placed on the image side of the third lens and at least partially contact the image side of the third lens. The fourth isolator may be placed on the image side of the fourth lens and at least partially contact the image side of the fourth lens. The fifth isolator may be placed on the image side of the fifth lens and at least partially contact the image side of the fifth lens. The sixth isolator may be placed on the image side of the sixth lens and at least partially contact the image side of the sixth lens. The seventh isolator may be placed on the image side of the seventh lens and at least partially contact the image side of the seventh lens. The reasonable use of isolators can effectively avoid the risk of stray light, reduce interference with image quality, and thus improve the imaging quality of the optical imaging system; at the same time, the bearing stability of the lens can also be ensured.

[0057] In an exemplary embodiment, the optical imaging system may further include a lens barrel, and the eight-piece lens group and the spacer group are placed in the lens barrel. The lens barrel may include an object side end face, an image side end face, an outer annular surface, and an inner annular surface, wherein the end face of the lens barrel closest to the object side is the object side end face of the lens barrel, and the end face of the lens barrel closest to the image side is the image side end face of the lens barrel; in a direction perpendicular to the optical axis, the surface of the lens barrel farthest from the optical axis is the outer annular surface, and the surface of the lens barrel closest to the optical axis is the inner annular surface. The inner annular surface of the lens barrel is stepped, and the inner diameter of the inner annular surface increases from the object side end face to the image side end face.

[0058] In an exemplary embodiment, the radius of curvature R16 of the image side of the eighth lens and the inner diameter d7m of the image side of the seventh spacer may satisfy: 1.5 < d7m / R16 < 4.2; and the effective focal length f8 of the eighth lens, the inner diameter d7m of the image side of the seventh spacer, and the outer diameter D7m of the image side of the seventh spacer may satisfy: 0 < (D7m - d7m) / |f8| < 1.40. By controlling the ratio of the difference between the outer and inner diameters of the image side of the seventh spacer to the effective focal length of the eighth lens, the effective focal length of the eighth lens can be constrained within a reasonable range, reducing the sensitivity of the optical imaging system. Additionally, since the light passing through the eighth lens is relatively steep and excessive inner diameter of the image side of the seventh spacer may generate stray light, by constraining the radius of curvature of the image side of the eighth lens, it can ensure that the light passing through the effective aperture at the edge of the eighth lens is refracted smoothly to the image plane. Meanwhile, by restricting the inner diameter of the image side of the seventh spacer within a reasonable range, it can effectively block the stray light refracted and reflected from the effective apertures at the edges of the seventh and eighth lenses, thereby improving the imaging quality of the optical imaging system.

[0059] Figure 2A FIG. is a simulation diagram of stray light of the optical imaging system when d7m / R16 = 1.98 and (D7m - d7m) / |f8| = 1.28, that is, when 1.5 < d7m / R16 < 4.2 and 0 < (D7m - d7m) / |f8| < 1.40. When the optical imaging system does not satisfy 1.5 < d7m / R16 < 4.2 and 0 < (D7m - d7m) / |f8| < 1.40, for example Figure 2B FIG. is a simulation diagram of stray light of the optical imaging system under the condition of d7m / R16 = 1.17 and (D7m - d7m) / |f8| = 1.53. From Figure 2B it can be seen that there is an obvious stray light phenomenon in the optical imaging system. From Figure 2A it can be seen that the stray light of the optical imaging system is reduced. It can be seen that when the optical imaging system satisfies "1.5 < d7m / R16 < 4.2, 0 < (D7m - d7m) / |f8| < 1.40", it can effectively improve the stray light phenomenon of the optical imaging system, thereby improving the imaging quality of the optical imaging system.

[0060] In an exemplary embodiment, the radius of curvature R16 of the image side of the eighth lens, the inner diameter d7s of the object side of the seventh spacer, and the outer diameter D7s of the object side of the seventh spacer may satisfy: 0 ≤ (D7s - d7s) / R16 ≤ 2.5. By controlling the ratio of the difference between the outer and inner diameters of the object side of the seventh spacer to the radius of curvature of the image side of the eighth lens, the size of the seventh spacer and the outer contour of the eighth lens can be reasonably adjusted, reducing the molding difficulty of the eighth lens and facilitating the molding of the eighth lens.

[0061] In an exemplary embodiment, the maximum length L of the lens barrel in the direction of the optical axis, the maximum value CTmax of the central thickness of each lens among the first lens to the eighth lens on the optical axis, and the maximum value ATmax of the air gap between two adjacent lenses among the first lens to the eighth lens on the optical axis may satisfy: 3.90 < L / (CTmax + ATmax) < 5.00. By controlling the above conditional expression, the maximum length of the lens barrel in the direction of the optical axis and the overall optical length of the optical imaging system can be constrained within a reasonable range, enabling the overall miniaturization of the optical imaging system, reducing the weight of the optical imaging system, and lowering the manufacturing cost of the optical imaging system.

[0062] In an exemplary embodiment, the effective focal length f8 of the eighth lens, the refractive index N8 of the eighth lens, the outer diameter D0s of the object-side end face of the lens barrel, and the outer diameter D0m of the image-side end face of the lens barrel may satisfy: -2.00 < f8×N8 / (D0m - D0s) < -1.00. By controlling the ratio of the product of the effective focal length and the refractive index of the eighth lens to the difference between the outer diameters of the image-side end face and the object-side end face of the lens barrel, the outer diameter size of the lens barrel and the uniformity of the lens barrel wall thickness can be reasonably constrained, avoiding structural interference problems when the lens barrel is配合 with the module. At the same time, the distance between the optical imaging system and the image plane can also be limited, ensuring that the optical imaging system and the chip are配合 within a reasonable range.

[0063] In an exemplary embodiment, the inner diameter d0s of the object-side end face of the lens barrel, the inner diameter d0m of the image-side end face of the lens barrel, and the total effective focal length f of the optical imaging system may satisfy: 1.00 < (d0m - d0s) / f < 1.60. By controlling the ratio of the difference between the inner diameters of the image-side end face and the object-side end face of the lens barrel to the total effective focal length of the optical imaging system, the uniformity of the lens barrel wall thickness can be reasonably constrained, enabling the lens barrel to have sufficient strength and stiffness, improving the forming stability and processing stability of the lens barrel, and at the same time ensuring that the true roundness of the inner diameter of the lens barrel is within the design requirements of the optical imaging system.

[0064] In an exemplary embodiment, the interval EP01 between the object-side end face of the lens barrel and the first spacer along the optical axis, the outer diameter D1s of the object-side surface of the first spacer, the central thickness CT1 of the first lens on the optical axis, and the maximum effective semi-aperture DT12 of the image-side surface of the first lens may satisfy: 4.50 < EP01 / CT1 + D1s / DT12 < 6.00. By controlling the above conditional expression, the head size of the optical imaging system can be reasonably constrained, and the first lens can have a reasonable central thickness and strength, improving the reliability of the optical imaging system; at the same time, the number of incident light rays can also be limited, avoiding more non-imaging light rays from entering the system while the optical imaging system has sufficient light transmittance, and improving the imaging effect and resolution of the optical imaging system.

[0065] In an exemplary embodiment, the combined focal length f23 of the second lens and the third lens and the outer diameter D2s of the object side surface of the second spacer may satisfy: -11 < f23 / D2s < 11. By controlling the ratio of the combined focal length of the second lens and the third lens to the outer diameter of the object side surface of the second spacer, the combined focal length of the second lens and the third lens can be constrained within a reasonable range, reducing the sensitivity of the optical imaging system. At the same time, by cooperating with restricting the outer diameter of the object side surface of the second spacer, the light flux of the optical imaging system can be effectively controlled to ensure that the brightness of the optical imaging system meets the design requirements.

[0066] In an exemplary embodiment, the combined focal length f23 of the second lens and the third lens, the outer diameter D2s of the object side surface of the second spacer, and the outer diameter D3s of the object side surface of the third spacer may satisfy: -0.30 < (D2s + D3s) / f23 < 0.30. By controlling the ratio of the sum of the outer diameters of the object side surfaces of the second spacer and the third spacer to the combined focal length of the second lens and the third lens, the overall field curvature of the optical imaging system can be reasonably constrained. At the same time, by cooperating with restricting the outer diameters of the object side surfaces of the second spacer and the third spacer, the assembly step difference between the second lens, the third lens and the corresponding spacers can be effectively regulated to improve the assembly stability of the optical imaging system.

[0067] In an exemplary embodiment, the central thickness CT5 of the fifth lens on the optical axis and the maximum thickness CP5 of the fifth spacer along the optical axis direction may satisfy: 0 < CP5 / CT5 < 1; the interval EP45 between the fourth spacer and the fifth spacer along the optical axis, the inner diameter d5m of the image side surface of the fifth spacer, and the outer diameter D5m of the image side surface of the fifth spacer may satisfy: 1.50 < (D5m - d5m) / EP45 < 10.00. By controlling the ratio of the central thickness of the fifth lens on the optical axis to the maximum thickness of the fifth spacer along the optical axis direction, the optical power of the fifth lens can be constrained, reducing the sensitivity of the fifth lens. At the same time, by cooperating with restricting the inner and outer diameters of the image side surface of the fifth spacer, an appropriate field of view angle of the optical imaging system can be ensured, so as to ensure that the optical imaging system can capture scenes in a large field of view range.

[0068] In an exemplary embodiment, the interval EP45 between the fourth spacer and the fifth spacer along the optical axis and the axial distance SAGH51 from the intersection of the object side surface of the fifth lens and the optical axis to the vertex of the maximum effective semi-aperture of the object side surface of the fifth lens may satisfy: 1.50 < EP45 / SAGH51 < 5.30. By controlling the above conditional formula, the uniformity of the thickness ratio between the middle thickness of the fifth lens and the edge thickness of the mechanism part (non-effective diameter part) can be reasonably constrained, so that the size of the thinnest part of the fifth lens is kept within a reasonable range, improving the forming processability of the fifth lens.

[0069] In an exemplary embodiment, the inner diameter d5s of the object side surface of the fifth spacer and the combined focal length f56 of the fifth lens and the sixth lens may satisfy: 1.20 < d5s / f56 < 1.50. By controlling the ratio of the inner diameter of the object side surface of the fifth spacer to the combined focal length of the fifth lens and the sixth lens, the difference in the outer diameter dimensions between the fifth lens and the sixth lens can be constrained within a reasonable range, avoiding a large assembly step difference between the fifth lens and the sixth lens caused by an excessive difference in the outer diameter dimensions of the fifth lens and the sixth lens, improving the assembly stability of the optical imaging system, and further reducing the sensitivity of the optical imaging system.

[0070] In an exemplary embodiment, the interval EP56 between the fifth spacer and the sixth spacer along the optical axis, the interval EP67 between the sixth spacer and the seventh spacer along the optical axis, the central thickness CT6 of the sixth lens on the optical axis, and the central thickness CT7 of the seventh lens on the optical axis may satisfy: 0.30 < (EP56 + EP67) / (CT6 + CT7) < 1.20. By controlling the above conditional expression, the ratio of the central thickness of the sixth lens and the seventh lens to the edge thickness of the mechanism part can be constrained within a reasonable range, which is beneficial to ensuring the reasonable shape of the sixth lens and the seventh lens, thereby ensuring that the forming of the sixth lens and the seventh lens does not exceed the processing limit.

[0071] In an exemplary embodiment, the interval EP56 between the fifth spacer and the sixth spacer along the optical axis and the axial distance SAGH52 from the intersection of the image side surface of the fifth lens and the optical axis to the vertex of the maximum effective semi-aperture of the image side surface of the fifth lens may satisfy: 0.50 < EP56 / SAGH52 < 4.10. By controlling the above conditional expression, the uniformity of the ratio of the central thickness of the fifth lens to the edge thickness of the mechanism part can be reasonably constrained, improving the forming processability of the fifth lens. At the same time, the uniformity of the edge thickness of the mechanism parts of the fifth lens and the sixth lens can be further regulated, improving the processability of the mechanism parts of the fifth lens and the sixth lens.

[0072] In an exemplary embodiment, the interval EP67 between the sixth spacer and the seventh spacer along the optical axis and the air gap T67 between the sixth lens and the seventh lens on the optical axis may satisfy: 0.60 < EP67 / T67 < 4.00. By controlling the ratio of the interval between the sixth spacer and the seventh spacer along the optical axis to the air gap between the sixth lens and the seventh lens on the optical axis, the air gap and the edge air gap between the sixth lens and the seventh lens can be effectively constrained. Under external conditions such as high temperature, high humidity, and dropping, the stability of the air gap between the sixth lens and the seventh lens can be improved, so that the imaging effect of the optical imaging system is less affected by external condition interference.

[0073] In an exemplary embodiment, the effective focal length f7 of the seventh lens, the curvature radius R13 of the object side surface of the seventh lens, the curvature radius R14 of the image side surface of the seventh lens, and the outer diameter D6s of the object side surface of the sixth spacer can satisfy: 0.15<|R13 / R14|×(D6s / f7)<1.20. By controlling the above conditional expression, the shape of the seventh lens can be reasonably constrained, and the stability of the molding process of the seventh lens can be improved. At the same time, by limiting the outer diameter of the object side surface of the sixth spacer and the effective focal length of the seventh lens, the sixth spacer can effectively intercept non-imaging light and improve the imaging quality of the optical imaging system.

[0074] The optical imaging system according to the above embodiment of the present application can use eight lenses and at least one spacer. By reasonably allocating the parameters of each lens, each spacer and the lens barrel, it is beneficial to the molding and assembly of the lens, reducing the intensity and quantity of ghost images and stray light of the optical imaging system, and improving the processability, assembly stability and imaging quality of the optical imaging system.

[0075] In an embodiment of the present application, at least one of the surfaces of each lens in the first lens to the eighth lens is an aspherical surface. The characteristic of an aspherical lens is that the curvature changes continuously from the center of the lens to the periphery of the lens. Unlike a spherical lens having a constant curvature from the center of the lens to the periphery of the lens, an aspherical lens has a better curvature radius characteristic, and has the advantages of improving distortion aberration and improving astigmatism aberration. After adopting an aspherical lens, the aberration that occurs during imaging can be eliminated as much as possible, thereby improving the imaging quality. Optionally, the object side surface and the image side surface of each lens in the first lens to the eighth lens are both aspherical surfaces.

[0076] The second aspect of the present application provides such an optical imaging system, which includes a lens barrel and an eight-piece lens group and a spacer group placed in the lens barrel. The eight-piece lens group includes a first lens with positive optical power, a second lens with positive optical power, a third lens with negative optical power, a fourth lens with negative optical power, a fifth lens with optical power, a sixth lens with positive optical power, a seventh lens with positive optical power, and an eighth lens with negative optical power, which are arranged in sequence from the object side to the image side along the optical axis. The object side surface of the first lens may be convex, and the image side surface may be concave. The object side surface of the second lens may be convex. The object side surface of the third lens may be concave, and the image side surface may be concave. The image side surface of the fifth lens may be concave. The object side surface of the sixth lens may be convex, and the image side surface may be convex. The object side surface of the seventh lens may be concave, and the image side surface may be convex. The image side surface of the eighth lens may be concave. The spacer group includes a fourth spacer disposed on and in contact with the image side surface of the fourth lens and a fifth spacer disposed on and in contact with the image side surface of the fifth lens.

[0077] Among them, the central thickness CT5 of the fifth lens on the optical axis and the maximum thickness CP5 of the fifth spacer along the optical axis direction can satisfy: 0 < CP5 / CT5 < 1; the interval EP45 between the fourth spacer and the fifth spacer along the optical axis, the inner diameter d5m of the image side of the fifth spacer and the outer diameter D5m of the image side of the fifth spacer can satisfy: 1.50 < (D5m - d5m) / EP45 < 10.00. By controlling the ratio of the central thickness of the fifth lens on the optical axis to the maximum thickness of the fifth spacer along the optical axis direction, the optical power of the fifth lens can be constrained, the sensitivity of the fifth lens can be reduced, and at the same time, by cooperating with restricting the inner and outer diameters of the image side of the fifth spacer, it can ensure that the optical imaging system has an appropriate field of view angle, thereby ensuring that the optical imaging system can capture scenes with a large field of view range.

[0078] Those skilled in the art should understand that without departing from the technical solutions claimed in this application, the number of lenses and spacers constituting the optical imaging system can be changed to obtain the various results and advantages described in this specification.

[0079] The following further describes specific embodiments of the optical imaging system applicable to the above embodiments with reference to the accompanying drawings.

[0080] Example 1

[0081] The following refers to Figure 3 Describe the optical imaging system according to Embodiment 1 of this application.

[0082] As Figure 3 shown, the optical imaging system includes a lens barrel and an eight-piece lens group and a spacer group disposed in the lens barrel. The eight-piece lens group sequentially includes: a first lens E1, a second lens E2, a third lens E3, a fourth lens E4, a fifth lens E5, a sixth lens E6, a seventh lens E7, and an eighth lens E8 from the object side to the image side along the optical axis. The aperture stop STO can be disposed between the object side and the first lens E1. The spacer group includes a first spacer P1, a second spacer P2, a third spacer P3, a fourth spacer P4, a fifth spacer P5, a sixth spacer P6, and a seventh spacer P7. The spacer can block the excess light in the imaging process from entering the next lens, and at the same time make the lens and the lens barrel better abutted, enhancing the structural stability of the optical imaging system.

[0083] The first lens E1 has positive focal power, and its object side surface S1 is convex, and its image side surface S2 is concave. The second lens E2 has positive focal power, and its object side surface S3 is convex, and its image side surface S4 is convex. The third lens E3 has negative focal power, and its object side surface S5 is concave, and its image side surface S6 is concave. The fourth lens E4 has negative focal power, and its object side surface S7 is convex, and its image side surface S8 is concave. The fifth lens E5 has positive focal power, and its object side surface S9 is convex, and its image side surface S10 is concave. The sixth lens E6 has positive focal power, and its object side surface S11 is convex, and its image side surface S12 is convex. The seventh lens E7 has positive focal power, and its object side surface S13 is concave, and its image side surface S14 is convex. The eighth lens E8 has negative focal power, and its object side surface S15 is concave, and its image side surface S16 is concave. The filter has an object side surface S17 (not shown) and an image side surface S18 (not shown). Light from the object passes through the surfaces S1 to S18 in sequence and is finally imaged on an imaging surface S19 (not shown).

[0084] Table 1 shows a basic parameter table of the optical imaging system of Example 1, wherein the units of the radius of curvature, thickness / distance, and focal length are all millimeters (mm).

[0085]

[0086] Table 1

[0087] In this embodiment, the total effective focal length f of the optical imaging system is 5.30 mm, the aperture number Fno of the optical imaging system is 1.65, and the maximum effective semi-aperture DT12 of the image side surface of the first lens is 1.71 mm.

[0088] In this embodiment, the object side surface and the image side surface of any lens among the first lens E1 to the eighth lens E8 are both aspherical surfaces, and the surface shape x of each aspherical lens can be defined by but not limited to the following aspherical surface formula:

[0089]

[0090] 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 (i.e., the paraxial curvature c is the reciprocal of the curvature radius R in Table 1 above); k is the cone coefficient; Ai is the correction coefficient of the i-th order of the aspheric surface. Table 2 shows the high-order coefficients A4, A6, A8, A9, A10, A11, A12, A13, A14, A15, A16, A17, A18, A19, A20, A21, A22, A23, A24, A25, A26, A27, A28, A29, A30, A31, A32, A33, A34, A35, A36, A37, A38, A39, A 10 , A 12 , A 14 , A 16 , A 18 , A 20 , A 22 , A24 , A 26 and A 28 .

[0091]

[0092] Table 2

[0093] Example 2

[0094] The following reference Figure 4 Describe the optical imaging system according to Example 2 of the present application.

[0095] like Figure 4 As shown, the optical imaging system includes a lens barrel and an eight-piece lens group and a spacer group placed in the lens barrel. The eight-piece lens group includes: a first lens E1, a second lens E2, a third lens E3, a fourth lens E4, a fifth lens E5, a sixth lens E6, a seventh lens E7 and an eighth lens E8 in order from the object side to the image side along the optical axis. The aperture STO can be arranged between the object side and the first lens E1. The spacer group includes a first spacer P1, a second spacer P2, a third spacer P3, a fourth spacer P4, a fifth spacer P5, a sixth spacer P6 and a seventh spacer P7.

[0096] The structure of the lens of this embodiment is the same as that of the lens of Embodiment 1, that is, the basic parameter table of the optical imaging system of this embodiment is the same as Table 1, and the aspheric coefficient table is the same as Table 2. The difference between this embodiment and Embodiment 1 is that the structural dimensions of at least some of the elements in the lens barrel, the first spacer P1, the second spacer P2, the third spacer P3, the fourth spacer P4, the fifth spacer P5, the sixth spacer P6, and the seventh spacer P7 are different.

[0097] Example 3

[0098] The following reference Figure 5 Describe the optical imaging system according to Example 3 of the present application.

[0099] like Figure 5 As shown, the optical imaging system includes a lens barrel and an eight-piece lens group and a spacer group placed in the lens barrel. The eight-piece lens group includes: a first lens E1, a second lens E2, a third lens E3, a fourth lens E4, a fifth lens E5, a sixth lens E6, a seventh lens E7 and an eighth lens E8 in order from the object side to the image side along the optical axis. The aperture STO can be arranged between the object side and the first lens E1. The spacer group includes a first spacer P1, a second spacer P2, a third spacer P3, a fourth spacer P4, a fifth spacer P5, a sixth spacer P6 and a seventh spacer P7.

[0100] The structure of the lens of this embodiment is the same as that of the lens of Embodiment 1, that is, the basic parameter table of the optical imaging system of this embodiment is the same as Table 1, and the aspheric coefficient table is the same as Table 2. The difference between this embodiment and Embodiment 1 is that the structural dimensions of at least some of the elements in the lens barrel, the first spacer P1, the second spacer P2, the third spacer P3, the fourth spacer P4, the fifth spacer P5, the sixth spacer P6, and the seventh spacer P7 are different.

[0101] Fig. 6A The axial chromatic aberration curves of the optical imaging systems of Examples 1, 2, and 3 are shown, which indicate the deviation of the focal point of light of different wavelengths after passing through the optical imaging system. Figure 6B Astigmatism curves of the optical imaging systems of Examples 1, 2, and 3 are shown, which represent the meridional image curvature and sagittal image curvature corresponding to different image heights. Figure 6C The distortion curves of the optical imaging systems of Examples 1, 2, and 3 are shown, which represent the distortion magnitude values ​​corresponding to different image heights. Fig.6D The magnification chromatic aberration curves of the optical imaging systems of Examples 1, 2, and 3 are shown, which represent the deviations of different image heights on the imaging surface after the light passes through the optical imaging system. FIG. 6A to FIG. 6D It can be seen that the optical imaging systems provided in Examples 1, 2, and 3 can achieve good imaging quality.

[0102] Example 4

[0103] The following reference Figure 7 Describe the optical imaging system according to Example 4 of the present application.

[0104] like Figure 7 As shown, the optical imaging system includes a lens barrel and an eight-piece lens group and a spacer group placed in the lens barrel. The eight-piece lens group includes: a first lens E1, a second lens E2, a third lens E3, a fourth lens E4, a fifth lens E5, a sixth lens E6, a seventh lens E7 and an eighth lens E8 in order from the object side to the image side along the optical axis. The aperture STO can be arranged between the object side and the first lens E1. The spacer group includes a first spacer P1, a second spacer P2, a third spacer P3, a fourth spacer P4, a fifth spacer P5, a sixth spacer P6 and a seventh spacer P7. The spacer can block the excess light in the imaging process from entering the next lens, and at the same time make the lens and the lens barrel better supported, thereby enhancing the structural stability of the optical imaging system.

[0105] The first lens E1 has positive focal power, and its object side surface S1 is convex, and its image side surface S2 is concave. The second lens E2 has positive focal power, and its object side surface S3 is convex, and its image side surface S4 is convex. The third lens E3 has negative focal power, and its object side surface S5 is concave, and its image side surface S6 is concave. The fourth lens E4 has negative focal power, and its object side surface S7 is convex, and its image side surface S8 is concave. The fifth lens E5 has negative focal power, and its object side surface S9 is concave, and its image side surface S10 is concave. The sixth lens E6 has positive focal power, and its object side surface S11 is convex, and its image side surface S12 is convex. The seventh lens E7 has positive focal power, and its object side surface S13 is concave, and its image side surface S14 is convex. The eighth lens E8 has negative focal power, and its object side surface S15 is convex, and its image side surface S16 is concave. The filter has an object side surface S17 (not shown) and an image side surface S18 (not shown). Light from the object passes through the surfaces S1 to S18 in sequence and is finally imaged on an imaging surface S19 (not shown).

[0106] Table 3 shows a basic parameter table of the optical imaging system of Example 4, wherein the units of the radius of curvature, thickness / distance, and focal length are all millimeters (mm).

[0107]

[0108] Table 3

[0109] In this embodiment, the total effective focal length f of the optical imaging system is 5.30 mm, the aperture number Fno of the optical imaging system is 1.65, and the maximum effective semi-aperture DT12 of the image side surface of the first lens is 1.73 mm.

[0110] In this embodiment, the object side surface and the image side surface of any lens from the first lens E1 to the eighth lens E8 are both aspherical surfaces. Table 4 lists the high-order coefficients A4, A6, A8, A9, A10, A11, A12, A13, A14, A15, A16, A17, A18, A19, A20, A21, A22, A23, A24, A25, A26, A27, A28, A29, A30, A31, A32, A33, A34, A35, A36, A37, A38, A39, A40, A41, A42, A43, A44, A45, A46, A47, A48, A49, A50, A51, A52, A53, A54, A55, A56, A57, A58, A59, A60, A61, A71, A72, A73, A74, A75 10 , A 12 , A 14 , A 16 , A 18 , A 20 , A 22 , A 24 , A 26 and A 28 .

[0111]

[0112]

[0113] Table 4

[0114] Example 5

[0115] The following reference Figure 8 Describe the optical imaging system according to Example 5 of the present application.

[0116] like Figure 8 As shown, the optical imaging system includes a lens barrel and an eight-piece lens group and a spacer group placed in the lens barrel. The eight-piece lens group includes: a first lens E1, a second lens E2, a third lens E3, a fourth lens E4, a fifth lens E5, a sixth lens E6, a seventh lens E7 and an eighth lens E8 in order from the object side to the image side along the optical axis. The aperture STO can be arranged between the object side and the first lens E1. The spacer group includes a first spacer P1, a second spacer P2, a third spacer P3, a fourth spacer P4, a fifth spacer P5, a sixth spacer P6 and a seventh spacer P7.

[0117] The structure of the lens of this embodiment is the same as that of the lens of Embodiment 4, that is, the basic parameter table of the optical imaging system of this embodiment is the same as Table 3, and the aspheric coefficient table is the same as Table 4. The difference between this embodiment and Embodiment 4 is that the structural dimensions of at least some of the elements in the lens barrel, the first spacer P1, the second spacer P2, the third spacer P3, the fourth spacer P4, the fifth spacer P5, the sixth spacer P6, and the seventh spacer P7 are different.

[0118] Example 6

[0119] The following reference Fig. 9 Describe the optical imaging system according to Example 6 of the present application.

[0120] like Fig. 9 As shown, the optical imaging system includes a lens barrel and an eight-piece lens group and a spacer group placed in the lens barrel. The eight-piece lens group includes: a first lens E1, a second lens E2, a third lens E3, a fourth lens E4, a fifth lens E5, a sixth lens E6, a seventh lens E7 and an eighth lens E8 in order from the object side to the image side along the optical axis. The aperture STO can be arranged between the object side and the first lens E1. The spacer group includes a first spacer P1, a second spacer P2, a third spacer P3, a fourth spacer P4, a fifth spacer P5, a sixth spacer P6 and a seventh spacer P7.

[0121] The structure of the lens of this embodiment is the same as that of the lens of Embodiment 4, that is, the basic parameter table of the optical imaging system of this embodiment is the same as Table 3, and the aspheric coefficient table is the same as Table 4. The difference between this embodiment and Embodiment 4 is that the structural dimensions of at least some of the elements in the lens barrel, the first spacer P1, the second spacer P2, the third spacer P3, the fourth spacer P4, the fifth spacer P5, the sixth spacer P6, and the seventh spacer P7 are different.

[0122] Fig. 10A The axial chromatic aberration curves of the optical imaging systems of Examples 4, 5, and 6 are shown, which indicate the deviation of the focal point of light of different wavelengths after passing through the optical imaging system. Fig. 10B Astigmatism curves of the optical imaging systems of Examples 4, 5, and 6 are shown, which represent the meridional image curvature and sagittal image curvature corresponding to different image heights. Fig. 10C The distortion curves of the optical imaging systems of Examples 4, 5 and 6 are shown, which represent the distortion magnitude values ​​corresponding to different image heights. Fig. 10D The magnification chromatic aberration curves of the optical imaging systems of Examples 4, 5, and 6 are shown, which represent the deviations of different image heights on the imaging surface after the light passes through the optical imaging system. FIG. 10A to FIG. 10D It can be seen that the optical imaging systems provided in Examples 4, 5 and 6 can achieve good imaging quality.

[0123] Example 7

[0124] The following reference Fig.11 Describe the optical imaging system according to Example 7 of the present application.

[0125] like Fig.11 As shown, the optical imaging system includes a lens barrel and an eight-piece lens group and a spacer group placed in the lens barrel. The eight-piece lens group includes: a first lens E1, a second lens E2, a third lens E3, a fourth lens E4, a fifth lens E5, a sixth lens E6, a seventh lens E7 and an eighth lens E8 in order from the object side to the image side along the optical axis. The aperture STO can be arranged between the object side and the first lens E1. The spacer group includes a first spacer P1, a second spacer P2, a third spacer P3, a fourth spacer P4, a fifth spacer P5, a sixth spacer P6 and a seventh spacer P7. The spacer can block the excess light in the imaging process from entering the next lens, and at the same time make the lens and the lens barrel better supported, thereby enhancing the structural stability of the optical imaging system.

[0126] The first lens E1 has positive focal power, and its object side surface S1 is convex, and its image side surface S2 is concave. The second lens E2 has positive focal power, and its object side surface S3 is convex, and its image side surface S4 is concave. The third lens E3 has negative focal power, and its object side surface S5 is concave, and its image side surface S6 is concave. The fourth lens E4 has negative focal power, and its object side surface S7 is concave, and its image side surface S8 is convex. The fifth lens E5 has positive focal power, and its object side surface S9 is convex, and its image side surface S10 is concave. The sixth lens E6 has positive focal power, and its object side surface S11 is convex, and its image side surface S12 is convex. The seventh lens E7 has positive focal power, and its object side surface S13 is concave, and its image side surface S14 is convex. The eighth lens E8 has negative focal power, and its object side surface S15 is convex, and its image side surface S16 is concave. The filter has an object side surface S17 (not shown) and an image side surface S18 (not shown). Light from the object passes through the surfaces S1 to S18 in sequence and is finally imaged on an imaging surface S19 (not shown).

[0127] Table 5 shows a basic parameter table of the optical imaging system of Example 7, wherein the units of the radius of curvature, thickness / distance, and focal length are all millimeters (mm).

[0128]

[0129]

[0130] Table 5

[0131] In this embodiment, the total effective focal length f of the optical imaging system is 5.30 mm, the aperture number Fno of the optical imaging system is 1.65, and the maximum effective semi-aperture DT12 of the image side surface of the first lens is 1.68 mm.

[0132] In this embodiment, the object side surface and the image side surface of any lens from the first lens E1 to the eighth lens E8 are both aspherical surfaces. Table 6 lists the high-order coefficients A4, A6, A8, A9, A10, A11, A12, A13, A14, A15, A16, A17, A18, A19, A20, A21, A22, A23, A24, A25, A26, A27, A28, A29, A30, A31, A32, A33, A34, A35, A36, A37, A38, A39, A40, A41, A42, A43, A44, A45, A46, A47, A48, A49, A50, A51, A52, A53, A54, A55, A56, A57, A58, A5 10 , A 12 , A 14 , A 16 , A 18 , A 20 , A 22 , A 24 , A 26 and A 28 .

[0133]

[0134] Table 6

[0135] Example 8

[0136] The following reference Fig.12 Describe the optical imaging system according to Example 8 of the present application.

[0137] like Fig.12 As shown, the optical imaging system includes a lens barrel and an eight-piece lens group and a spacer group placed in the lens barrel. The eight-piece lens group includes: a first lens E1, a second lens E2, a third lens E3, a fourth lens E4, a fifth lens E5, a sixth lens E6, a seventh lens E7 and an eighth lens E8 in order from the object side to the image side along the optical axis. The aperture STO can be arranged between the object side and the first lens E1. The spacer group includes a first spacer P1, a second spacer P2, a third spacer P3, a fourth spacer P4, a fifth spacer P5, a sixth spacer P6 and a seventh spacer P7.

[0138] The structure of the lens of this embodiment is the same as that of the lens of Embodiment 7, that is, the basic parameter table of the optical imaging system of this embodiment is the same as Table 5, and the aspheric coefficient table is the same as Table 6. The difference between this embodiment and Embodiment 7 is that the structural dimensions of at least some of the elements in the lens barrel, the first spacer P1, the second spacer P2, the third spacer P3, the fourth spacer P4, the fifth spacer P5, the sixth spacer P6, and the seventh spacer P7 are different.

[0139] Example 9

[0140] The following reference Fig.13 Describe the optical imaging system according to Example 9 of the present application.

[0141] like Fig.13 As shown, the optical imaging system includes a lens barrel and an eight-piece lens group and a spacer group placed in the lens barrel. The eight-piece lens group includes: a first lens E1, a second lens E2, a third lens E3, a fourth lens E4, a fifth lens E5, a sixth lens E6, a seventh lens E7 and an eighth lens E8 in order from the object side to the image side along the optical axis. The aperture STO can be arranged between the object side and the first lens E1. The spacer group includes a first spacer P1, a second spacer P2, a third spacer P3, a fourth spacer P4, a fifth spacer P5, a sixth spacer P6 and a seventh spacer P7.

[0142] The structure of the lens of this embodiment is the same as that of the lens of Embodiment 7, that is, the basic parameter table of the optical imaging system of this embodiment is the same as Table 5, and the aspheric coefficient table is the same as Table 6. The difference between this embodiment and Embodiment 7 is that the structural dimensions of at least some of the elements in the lens barrel, the first spacer P1, the second spacer P2, the third spacer P3, the fourth spacer P4, the fifth spacer P5, the sixth spacer P6, and the seventh spacer P7 are different.

[0143] Fig.14A The axial chromatic aberration curves of the optical imaging systems of Examples 7, 8, and 9 are shown, which indicate the deviation of the focal point of light of different wavelengths after passing through the optical imaging system. Fig. 14B The astigmatism curves of the optical imaging systems of Examples 7, 8, and 9 are shown, which represent the meridional image curvature and sagittal image curvature corresponding to different image heights. Fig. 14C The distortion curves of the optical imaging systems of Examples 7, 8 and 9 are shown, which represent the distortion magnitude values ​​corresponding to different image heights. Fig.14D The magnification chromatic aberration curves of the optical imaging systems of Examples 7, 8, and 9 are shown, which represent the deviations of different image heights on the imaging surface after the light passes through the optical imaging system. FIG. 14A to FIG. 14D It can be seen that the optical imaging systems provided in Examples 7, 8 and 9 can achieve good imaging quality.

[0144] Table 7 shows the values ​​of parameters such as D1s, D2s, D3s, d5s, d5m, D5m, D6s, d7s, d7m, D7s, D7m, d0s, d0m, D0s, D0m, EP01, EP45, CP5, EP56, EP67, L, SAGH51 and SAGH52 in each of Examples 1-9. The above parameters can be calculated according to Figure 1 The units of the parameters listed in Table 7 are all mm.

[0145]

[0146]

[0147] Table 7

[0148] Table 8 shows the values ​​of the conditional expressions of each of Examples 1 to 9.

[0149] Conditional / Example 1 2 3 4 5 6 7 8 9 d7m / R16 1.79 1.79 1.79 3.87 3.87 3.90 2.54 2.54 2.54 (D7m-d7m) / |f8| 0.16 0.16 0.43 0.85 0.22 0.91 0.88 0.37 1.32 (D7s-d7s) / R16 0.17 0.17 0.45 2.22 0.59 2.40 1.50 0.63 2.27 CP5 / CT5 0.03 0.92 0.97 0.03 0.03 0.52 0.02 0.02 0.90 (D5m-d5m) / EP45 5.40 1.54 1.67 6.48 6.40 4.03 4.41 9.89 5.22 EP67 / T67 0.79 0.68 0.79 3.62 3.62 3.88 1.60 1.60 1.68 L / (CTmax+ATmax) 3.94 3.94 4.32 4.65 4.65 4.74 4.57 4.57 4.82 EP01 / CT1+D1s / DT12 4.63 5.13 5.92 5.28 4.84 5.54 4.97 4.58 5.32 |R13 / R14|×(D6s / f7) 0.99 1.15 1.15 0.20 0.17 0.20 0.52 0.40 0.39 d5s / f56 1.31 1.31 1.29 1.46 1.46 1.47 1.43 1.42 1.43 f23 / D2s 10.21 8.31 8.13 7.19 8.58 8.18 -8.93 -10.32 -8.11 f8×N8 / (D0m-D0s) -1.53 -1.53 -1.19 -1.27 -1.32 -1.45 -1.21 -1.47 -1.01 (EP56+EP67) / (CT6+CT7) 0.78 0.38 0.39 1.09 1.09 0.92 1.09 1.09 0.66 (d0m-d0s) / f 1.07 1.07 1.48 1.22 1.22 1.22 1.13 1.04 1.55 (D2s+D3s) / f23 0.20 0.25 0.25 0.28 0.23 0.28 -0.23 -0.19 -0.22 EP45 / SAGH51 2.61 2.61 2.61 1.70 1.70 1.76 3.95 3.95 5.14 EP56 / SAGH52 4.06 1.58 1.44 1.38 1.38 0.81 1.91 1.91 0.67

[0150] Table 8

[0151] 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.

[0152] The above description is only a preferred embodiment of the present application and an explanation of the technical principles used. Those skilled in the art should understand that the scope of the utility model involved in the present application is not limited to the technical solution formed by a specific combination of the above technical features, but should also cover other technical solutions formed by any combination of the above technical features or their equivalent features without departing from the inventive concept. For example, the above features are replaced with the technical features with similar functions disclosed in the present application (but not limited to) by each other.

Claims

1. An optical imaging system, characterized in that: Comprising: An eight-piece lens group, including a first lens with a positive focal power, a second lens with a positive focal power, a third lens with a negative focal power, a fourth lens with a negative focal power, a fifth lens with a focal power, a sixth lens with a positive focal power, a seventh lens with a positive focal power, and an eighth lens with a negative focal power, which are arranged in sequence from the object side to the image side along the optical axis; An isolator group, including a seventh isolator placed on and in contact with the image side surface of the seventh lens; And A lens barrel, in which the eight-piece lens group and the isolator group are placed; Wherein, the radius of curvature R16 of the image side surface of the eighth lens and the inner diameter d7m of the image side surface of the seventh isolator satisfy: 1.5 < d7m / R16 < 4.2; and The effective focal length f8 of the eighth lens, the inner diameter d7m of the image side surface of the seventh isolator, and the outer diameter D7m of the image side surface of the seventh isolator satisfy: 0 < (D7m - d7m) / |f8| < 1.

40.

2. The optical imaging system according to claim 1, characterized in that: The radius of curvature R16 of the image side surface of the eighth lens, the inner diameter d7s of the object side surface of the seventh isolator, and the outer diameter D7s of the object side surface of the seventh isolator satisfy: 0 ≤ (D7s - d7s) / R16 ≤ 2.

5.

3. The optical imaging system according to claim 1, characterized in that: The maximum length L of the lens barrel in the direction of the optical axis, the maximum value CTmax of the central thickness of each lens from the first lens to the eighth lens on the optical axis, and the maximum value ATmax of the air gap between adjacent two lenses from the first lens to the eighth lens on the optical axis satisfy: 3.90 < L / (CTmax + ATmax) < 5.

00.

4. The optical imaging system according to claim 1, characterized in that: The effective focal length f8 of the eighth lens, the refractive index N8 of the eighth lens, the outer diameter D0s of the object side end surface of the lens barrel, and the outer diameter D0m of the image side end surface of the lens barrel satisfy: -2.00 < f8×N8 / (D0m - D0s) < -1.

00.

5. The optical imaging system according to claim 1, characterized in that: The inner diameter d0s of the object side end surface of the lens barrel, the inner diameter d0m of the image side end surface of the lens barrel, and the total effective focal length f of the optical imaging system satisfy: 1.00 < (d0m - d0s) / f < 1.

60.

6. The optical imaging system according to any one of claims 1 to 5, characterized in that: The isolator group further includes a first isolator placed on and in contact with the image side surface of the first lens, Wherein, the interval EP01 between the object side end surface of the lens barrel and the first isolator along the optical axis, the outer diameter D1s of the object side surface of the first isolator, the central thickness CT1 of the first lens on the optical axis, and the maximum effective semi-aperture DT12 of the image side surface of the first lens satisfy: 4.50 < EP01 / CT1 + D1s / DT12 < 6.

00.

7. The optical imaging system according to any one of claims 1 to 5, characterized in that: The isolator group further includes a second isolator placed on and in contact with the image side surface of the second lens, Wherein, the combined focal length f23 of the second lens and the third lens and the outer diameter D2s of the object side surface of the second isolator satisfy: -11 < f23 / D2s < 11.

8. The optical imaging system according to any one of claims 1 to 5, characterized in that: The spacer group further includes a second spacer disposed on and in contact with the image side of the second lens and a third spacer disposed on and in contact with the image side of the third lens. Wherein, the combined focal length f23 of the second lens and the third lens, the outer diameter D2s of the object side of the second spacer and the outer diameter D3s of the object side of the third spacer satisfy: -0.30 < (D2s + D3s) / f23 < 0.

30.

9. The optical imaging system according to any one of claims 1 to 5, characterized in that: The spacer group further includes a fourth spacer disposed on and in contact with the image side of the fourth lens and a fifth spacer disposed on and in contact with the image side of the fifth lens. Wherein, the central thickness CT5 of the fifth lens on the optical axis and the maximum thickness CP5 of the fifth spacer along the optical axis direction satisfy: 0 < CP5 / CT5 < 1; the interval EP45 between the fourth spacer and the fifth spacer along the optical axis, the inner diameter d5m of the image side of the fifth spacer and the outer diameter D5m of the image side of the fifth spacer satisfy: 1.50 < (D5m - d5m) / EP45 < 10.

00.

10. The optical imaging system according to any one of claims 1 to 5, characterized in that: The spacer group further includes a fourth spacer disposed on and in contact with the image side of the fourth lens and a fifth spacer disposed on and in contact with the image side of the fifth lens. Wherein, the interval EP45 between the fourth spacer and the fifth spacer along the optical axis and the axial distance SAGH51 from the intersection of the object side of the fifth lens and the optical axis to the vertex of the maximum effective semi-aperture of the object side of the fifth lens satisfy: 1.50 < EP45 / SAGH51 < 5.

30.

11. The optical imaging system according to any one of claims 1 to 5, characterized in that: The spacer group further includes a fifth spacer disposed on and in contact with the image side of the fifth lens. Wherein, the inner diameter d5s of the object side of the fifth spacer and the combined focal length f56 of the fifth lens and the sixth lens satisfy: 1.20 < d5s / f56 < 1.

50.

12. The optical imaging system according to any one of claims 1 to 5, characterized in that: The spacer group further includes a fifth spacer disposed on and in contact with the image side of the fifth lens and a sixth spacer disposed on and in contact with the image side of the sixth lens. Wherein, the interval EP56 between the fifth spacer and the sixth spacer along the optical axis, the interval EP67 between the sixth spacer and the seventh spacer along the optical axis, the central thickness CT6 of the sixth lens on the optical axis and the central thickness CT7 of the seventh lens on the optical axis satisfy: 0.30 < (EP56 + EP67) / (CT6 + CT7) < 1.

20.

13. The optical imaging system according to any one of claims 1 to 5, characterized in that: The spacer group further includes a fifth spacer disposed on and in contact with the image side of the fifth lens and a sixth spacer disposed on and in contact with the image side of the sixth lens. The interval EP56 between the fifth spacer and the sixth spacer along the optical axis and the on-axis distance SAGH52 from the intersection of the image side surface of the fifth lens and the optical axis to the maximum effective semi-aperture vertex of the image side surface of the fifth lens satisfy: 0.50 <EP56 / SAGH52<4.10。 14. The optical imaging system according to any one of claims 1 to 5, characterized in that: The spacer set further includes a sixth spacer disposed on the image side surface of the sixth lens and in contact with the image side surface of the sixth lens. The interval EP67 between the sixth spacer and the seventh spacer along the optical axis and the air interval T67 between the sixth lens and the seventh lens on the optical axis satisfy: 0.60 <EP67 / T67<4.00。 15. The optical imaging system according to any one of claims 1 to 5, characterized in that: The spacer set further includes a sixth spacer disposed on the image side surface of the sixth lens and in contact with the image side surface of the sixth lens. Among them, the effective focal length f7 of the seventh lens, the curvature radius R13 of the object side surface of the seventh lens, the curvature radius R14 of the image side surface of the seventh lens and the outer diameter D6s of the object side surface of the sixth isolation member satisfy: 0.15<|R13 / R14|×(D6s / f7)<1.20.

Images