Optical imaging system

Abstract

The application discloses an optical imaging system, which comprises a lens barrel, an eight-piece lens group and a spacer element group arranged in the lens barrel, the eight-piece lens group comprises 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 along an optical axis from an object side to an image side, wherein the effective focal length of the eighth lens is less than zero, and the curvature radius of the object side surface and the image side surface of the eighth lens is greater than zero; the spacer element group comprises a seventh spacer element abutting against the image side surface of the seventh lens; the inner diameter of the image side surface of the seventh spacer element is d7m, the outer diameter of the image side surface of the seventh spacer element is D7m, the curvature radius of the object side surface of the eighth lens is R15, and the curvature radius of the image side surface of the eighth lens is R16, and the following conditions are met: 5<(d7m+D7m) / (R15‑R16)<32, and the half of the maximum field angle of the optical imaging system Semi-FOV, the total effective focal length f of the optical imaging system, the effective focal length f8 of the eighth lens and the length L of the lens barrel in the direction of the optical axis satisfy the following condition: 0<tan(Semi-FOV)×(f‑f8) / L<8.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of optical devices, in particular to an eight-piece optical imaging system. BACKGROUND

[0002] With the update iteration of mobile electronic devices, higher requirements are put forward for the optical imaging system of the mobile electronic devices, for example, by optical design of the optical imaging system, so that the optical imaging system has a larger field of view angle.

[0003] In order to make the optical imaging system have a larger field of view angle, the optical imaging system is usually arranged in the form of an eight-piece lens structure, and there are more mechanisms and components for bearing and mounting in the optical imaging system, and there are more components that can produce stray light, for example, when the size of the object side end or the image side end of the lens barrel is not reasonable matched with the lens, stray light will be generated, thereby affecting the cleanliness of the imaging of the optical imaging system. At the same time, the optical imaging system cannot meet the requirement of light weight due to its larger shape structure. SUMMARY

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

[0005] An aspect of the present application provides an optical imaging system, which comprises a lens barrel, and an eight-piece lens group and a spacer element group arranged in the lens barrel, the eight-piece lens group comprises 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 order from an object side to an image side along an optical axis, wherein the effective focal length of the eighth lens is less than zero, and the curvature radius of the object side surface and the image side surface of the eighth lens are both greater than zero; the spacer element group comprises a seventh spacer element bearing on the image side surface of the seventh lens; wherein the inner diameter d7m of the image side surface of the seventh spacer element, the outer diameter D7m of the image side surface of the seventh spacer element, the curvature radius R15 of the object side surface of the eighth lens and the curvature radius R16 of the image side surface of the eighth lens satisfy: 5 < (d7m+D7m) / (R15-R16) < 32, and the half of the maximum field of view angle Semi-FOV of the optical imaging system, the total effective focal length f of the optical imaging system, the effective focal length f8 of the eighth lens and the length L of the lens barrel in the direction of the optical axis satisfy: 0 < tan(Semi-FOV)×(f-f8) / L < 8.

[0006] According to one exemplary embodiment of the present application, the effective focal length of the seventh lens is less than zero, and the effective focal length f7 of the seventh lens, the air separation T78 of the seventh lens and the eighth lens on the optical axis, the central thickness CT8 of the eighth lens on the optical axis, the inner diameter d7s of the object side surface of the seventh spacer element, the outer diameter D7s of the object side surface of the seventh spacer element, and the maximum thickness CP7 of the seventh spacer element satisfy: 15 < (d7s / CP7 + D7s / CT8) / f7 x T78 < 65.

[0007] According to one exemplary embodiment of the present application, the radius of curvature R11 of the object side surface of the sixth lens and the radius of curvature R12 of the image side surface of the sixth lens satisfy: 0.5 < R12 / R11 < 4, and the radius of curvature R12 of the image side surface of the sixth lens and the radius of curvature R13 of the object side surface of the seventh lens satisfy: -1.5 < R13 / R12 < 0.

[0008] According to one exemplary embodiment of the present application, the spacer element group further includes a sixth spacer element abutting against the image side surface of the sixth lens, wherein the inner diameter d6s of the object side surface of the sixth spacer element, the radius of curvature R12 of the image side surface of the sixth lens and the radius of curvature R13 of the object side surface of the seventh lens satisfy: -7 < d6s / (R12+R13) < 0, and the outer diameter D6m of the image side surface of the sixth spacer element, the radius of curvature R11 of the object side surface of the sixth lens and the radius of curvature R12 of the image side surface of the sixth lens satisfy: 0 < D6m / (R11-R12) < 7.

[0009] According to one exemplary embodiment of the present application, the spacer element group further includes a sixth spacer element abutting against the image side surface of the sixth lens, wherein the effective focal length f6 of the sixth lens, the effective focal length f7 of the seventh lens, the effective focal length f8 of the eighth lens, the maximum thickness CP6 of the sixth spacer element, the maximum thickness CP7 of the seventh spacer element, and the separation EP67 of the sixth spacer element and the seventh spacer element along the optical axis satisfy: -35 < (f6+f7+f8) / (CP6+EP67+CP7) < -5.

[0010] According to one exemplary embodiment of the present application, the spacer element group further includes a third spacer element abutting against the image side surface of the third lens, wherein the inner diameter d3s of the object side surface of the third spacer element, the outer diameter D3m of the image side surface of the third spacer element, the effective focal length f3 of the third lens, the radius of curvature R7 of the object side surface of the fourth lens and the radius of curvature R8 of the image side surface of the fourth lens satisfy: -32 mm < (R7-R8) x (d3s+D3m) / f3 < -5 mm.

[0011] According to one example embodiment of the present application, the spacer element group further includes a fourth spacer element abutting against the image side surface of the fourth lens, a fifth spacer element abutting against the image side surface of the fifth lens, and a sixth spacer element abutting against the image side surface of the sixth lens, wherein the effective focal length f4 of the fourth lens, the effective focal length f5 of the fifth lens, and the interval EP45 of the fourth and fifth spacer elements along the optical axis satisfy: 0mm < f5 x EP45 / f4 < 6mm, and the effective focal length f5 of the fifth lens, the effective focal length f6 of the sixth lens, and the interval EP56 of the fifth and sixth spacer elements along the optical axis satisfy: 50 < (f5 + f6) / EP56 < 160.

[0012] According to one example embodiment of the present application, the spacer element group further includes a fourth spacer element abutting against the image side surface of the fourth lens, wherein the radius of curvature R7 of the object side surface of the fourth lens, the radius of curvature R9 of the object side surface of the fifth lens, and the inner diameter d4s of the object side surface of the fourth spacer element satisfy: 6 < (R7 + R9) / d4s < 25.

[0013] According to one example embodiment of the present application, the spacer element group further includes a fourth spacer element abutting against the image side surface of the fourth lens and a fifth spacer element abutting against the image side surface of the fifth lens, wherein the radius of curvature R8 of the image side surface of the fourth lens, the radius of curvature R10 of the image side surface of the fifth lens, the inner diameter d4m of the image side surface of the fourth spacer element, and the outer diameter D5m of the image side surface of the fifth spacer element satisfy: -14 < (R8 - R10) / (D5m + d4m) < 0.

[0014] According to one example embodiment of the present application, the spacer element group further includes a fourth spacer element abutting against the image side surface of the fourth lens and a fifth spacer element abutting against the image side surface of the fifth lens, wherein the outer diameter D4s of the object side surface of the fourth spacer element, the outer diameter D4m of the image side surface of the fourth spacer element, the maximum thickness CP4 of the fourth spacer element, the maximum thickness CP5 of the fifth spacer element, and the air interval T45 of the fourth and fifth lenses along the optical axis satisfy: 2 < (D4s + D4m) / (CP4 + T45 + CP5) < 40.

[0015] According to one example embodiment of the present application, the inner diameter d0s of the object side end surface of the lens barrel, the outer diameter D0s of the object side end surface of the lens barrel, the F-number Fno of the optical imaging system, and the effective focal length f1 of the first lens satisfy: 0 < (d0s + D0s) / f1 x Fno < 7.

[0016] According to an example embodiment of the present application, the set of spacer elements further comprises a fourth spacer element abutting the image side surface of the fourth lens, wherein the effective focal length f4 of the fourth lens, the inner diameter d4s of the object side surface of the fourth spacer element, and the outer diameter D4s of the object side surface of the fourth spacer element satisfy: 0 < f4 / (D4s-d4s) < 17.

[0017] According to an example embodiment of the present application, the set of spacer elements further comprises a fifth spacer element abutting the image side surface of the fifth lens, wherein the effective focal length f5 of the fifth lens, the inner diameter d5s of the object side surface of the fifth spacer element, and the outer diameter D5s of the object side surface of the fifth spacer element satisfy: 18 < f5 / (D5s-d5s) < 60.

[0018] According to an example embodiment of the present application, the set of spacer elements further comprises a first spacer element abutting the image side surface of the first lens, wherein the radius of curvature R1 of the object side surface of the first lens, the radius of curvature R2 of the image side surface of the first lens, the outer diameter D1s of the object side surface of the first spacer element, and the inner diameter d1m of the image side surface of the first spacer element satisfy: 2 < (R1+R2) / (D1s-d1m) < 24.

[0019] According to an example embodiment of the present application, the set of spacer elements further comprises a first spacer element abutting the image side surface of the first lens and a second spacer element abutting the image side surface of the second lens, wherein the radius of curvature R3 of the object side surface of the second lens, the radius of curvature R4 of the image side surface of the second lens, the inner diameter d2s of the object side surface of the second spacer element, the outer diameter D2m of the image side surface of the second spacer element, and the interval EP12 of the first spacer element and the second spacer element along the optical axis satisfy: 12 < (R3 / R4) x (D2m+d2s) / EP12 < 40.

[0020] The present application can effectively control the light transmission quality of the optical imaging system, control the edge light to be away from the object side end surface of the lens barrel and the position of the bevel connected with the object side end surface and the position of the exit hole of the tail end of the lens barrel under the premise of ensuring that the optical imaging system has an image height matching the chip, avoid the generation of light source concentric circular arc flare and red arc flare at the two positions respectively, thereby improving the cleanliness of the imaging of the optical imaging system; meanwhile, the present application can also improve the field of view angle of the optical imaging system under the premise of ensuring that the optical imaging system has a shorter lens barrel length, reduce the head size of the optical imaging system, and make the optical imaging system meet the design index of light weight. BRIEF DESCRIPTION OF DRAWINGS

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

[0022] Figure 1A structural diagram of an optical imaging system according to the present application is shown;

[0023] Figure 2 A structural diagram of an optical imaging system according to Embodiment 1 of the first embodiment of the present application is shown;

[0024] Figure 3 A structural diagram of an optical imaging system according to Embodiment 2 of the first embodiment of the present application is shown;

[0025] Figure 4 A structural diagram of an optical imaging system according to Embodiment 3 of the first embodiment of the present application is shown;

[0026] Figures 5A to 5D An on-axis chromatic aberration curve, an astigmatism curve, a distortion curve, and a magnification chromatic aberration curve of the optical imaging system according to the first embodiment of the present application are shown, respectively;

[0027] Figure 6 A structural diagram of an optical imaging system according to Embodiment 1 of the second embodiment of the present application is shown;

[0028] Figure 7 A structural diagram of an optical imaging system according to Embodiment 2 of the second embodiment of the present application is shown;

[0029] Figure 8 A structural diagram of an optical imaging system according to Embodiment 3 of the second embodiment of the present application is shown;

[0030] Figures 9A to 9D An on-axis chromatic aberration curve, an astigmatism curve, a distortion curve, and a magnification chromatic aberration curve of the optical imaging system according to the second embodiment of the present application are shown, respectively;

[0031] Figure 10 A structural diagram of an optical imaging system according to Embodiment 1 of the third embodiment of the present application is shown;

[0032] Figure 11 A structural diagram of an optical imaging system according to Embodiment 2 of the third embodiment of the present application is shown;

[0033] Figure 12 A structural diagram of an optical imaging system according to Embodiment 3 of the third embodiment of the present application is shown; and

[0034] Figures 13A to 13D An on-axis chromatic aberration curve, an astigmatism curve, a distortion curve, and a magnification chromatic aberration curve of the optical imaging system according to the third embodiment of the present application are shown, respectively. DETAILED DESCRIPTION

[0035] For a better understanding of the present application, various aspects of the present application will be presented in more detail by referring to the attached drawings. It should be noted that these detailed description is merely a description of exemplary embodiments of the present application, and does not limit the scope of the present application in any way. Throughout the specification, like drawing reference numerals will be used to refer to like elements throughout the specification.

[0036] It should be noted that the terms first, second, third, etc. in the present specification are merely used to distinguish one feature from another, and do not represent any limitation on the features. Thus, the first lens discussed below can also be referred to as the second lens or the third lens without departing from the teachings of the present application.

[0037] In the drawings, the thickness, size, and shape of the lenses have been slightly exaggerated for ease of explanation. Specifically, the shape of the spherical or aspherical surface shown in the drawings is shown by way of example. That is, the shape of the spherical or aspherical surface is not limited to the shape of the spherical or aspherical surface shown in the drawings. The drawings are merely examples and are not drawn strictly to scale.

[0038] In this context, the paraxial region refers to a 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 side is referred to as the object side surface of the lens, and the surface of each lens closest to the image side is referred to as the image side surface of the lens.

[0039] It should also be understood that the terms "comprise", "comprising", "have", "having", "include" and / or "including" when used in this specification, mean the presence of stated features, elements and / or components but do not preclude the presence or addition of one or more other features, elements, components and / or groups thereof. In addition, when describing the embodiments of the present application, the use of "may" means "one or more embodiments of the present application". Also, the term "exemplary" is intended to mean an example or an illustration.

[0040] Unless otherwise defined, all terms used in this document including technical terms and scientific terms have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. It should also be understood that the terms used in the specification (for example, terms defined in commonly used dictionaries) should be interpreted as having a meaning that is consistent with their meaning in the context of the relevant art and will not be interpreted in an idealized or overly formal sense unless expressly so defined in this document.

[0041] It should be noted that the embodiments in the present application and the features in the embodiments can be combined with each other without conflict. The present application will be described in more detail below with reference to the drawings and in combination with the embodiments.

[0042] The features, principles, and other aspects of the present application are described in detail below.

[0043] As shown in Figures 2 to 4 , Figures 6 to 8 and Figures 10 to 12 , the optical imaging system according to the exemplary embodiment of the present application can include a lens barrel and an eight-piece lens group disposed in the lens barrel, the eight-piece lens group can include, in order from the object side to the image side along the optical axis, a first lens, a second lens, a third lens, a fourth lens, a fifth lens, a sixth lens, a seventh lens, and an eighth lens. Among the first lens to the eighth lens, any two adjacent lenses can have an air gap therebetween. The effective focal length of the eighth lens is less than zero, and the radii of curvature of the object side and the image side of the eighth lens are both greater than zero.

[0044] The optical imaging system can further include a spacer element group disposed in the lens barrel, the spacer element group can include a seventh spacer element abutting against the image side of the seventh lens. In an example, the inner diameter d7m of the image side of the seventh spacer element, the outer diameter D7m of the image side of the seventh spacer element, the radius of curvature R15 of the object side of the eighth lens, and the radius of curvature R16 of the image side of the eighth lens can satisfy: 5 < (d7m + D7m) / (R15 - R16) < 32, and the half of the maximum field of view angle Semi-FOV of the optical imaging system, the total effective focal length f of the optical imaging system, the effective focal length f8 of the eighth lens, and the length L of the lens barrel in the direction of the optical axis can satisfy: 0 < tan(Semi-FOV) x (f - f8) / L < 8. In an example, 10 < (d7m + D7m) / (R15 - R16) < 28, and 1 < tan(Semi-FOV) x (f - f8) / L < 3.5. By controlling the above conditional expressions, the light transmission quality of the optical imaging system can be effectively controlled, the edge light is controlled to be away from the position of the object side end surface of the lens barrel and the bevel connected with the object side end surface and the position of the hole at the tail end of the lens barrel, to avoid the generation of light source concentric circular arc flare and red arc flare at the two positions respectively, thereby improving the cleanliness of the imaging of the optical imaging system; meanwhile, the field of view angle of the optical imaging system can be improved and the head size of the optical imaging system can be reduced under the premise of ensuring that the optical imaging system has a relatively short lens barrel length, so that the optical imaging system meets the design index of light weight, reduces the motor driving load, and improves the focusing efficiency. It can be seen that by controlling the above conditional expressions, the optical imaging system can realize the characteristics of a wide shooting range and a high imaging pixel in a small volume range.

[0045] In other examples, the set of spacer elements can further include one or more of a first spacer element, a second spacer element, a third spacer element, a fourth spacer element, a fifth spacer element, and a sixth spacer element. The first spacer element abuts the image side surface of the first lens; the second spacer element abuts the image side surface of the second lens; the third spacer element abuts the image side surface of the third lens; the fourth spacer element abuts the image side surface of the fourth lens; the fifth spacer element abuts the image side surface of the fifth lens; and the sixth spacer element abuts the image side surface of the sixth lens. Reasonable use of the spacer elements can effectively avoid stray light risks, reduce interference with image quality, and thus improve the imaging quality of the optical imaging system.

[0046] In example embodiments, the effective focal length of the seventh lens is less than zero, and the effective focal length f7 of the seventh lens, the air separation T78 of the seventh lens and the eighth lens on the optical axis, the central thickness CT8 of the eighth lens on the optical axis, the inner diameter d7s of the object side surface of the seventh spacer element, the outer diameter D7s of the object side surface of the seventh spacer element, and the maximum thickness CP7 of the seventh spacer element satisfy: 15 < (d7s / CP7 + D7s / CT8) / f7 x T78 < 65. By controlling the above condition, the central thickness and the edge thickness of the eighth lens can be constrained within a reasonable range, the risk of weld marks of the eighth lens during molding is reduced, and the stray light risk caused by the weld marks is reduced, thereby improving the cleanliness of the optical imaging system. At the same time, the air separation of the seventh lens and the eighth lens on the optical axis can be limited within a certain range to avoid assembly interference of the seventh lens and the eighth lens.

[0047] In example embodiments, the radius of curvature R11 of the object side surface of the sixth lens and the radius of curvature R12 of the image side surface of the sixth lens satisfy: 0.5 < R12 / R11 < 4, and the radius of curvature R12 of the image side surface of the sixth lens and the radius of curvature R13 of the object side surface of the seventh lens satisfy: -1.5 < R13 / R12 < 0. In examples, 1.5 < R12 / R11 < 2.5, and -1 < R13 / R12 < -0.5. By controlling the above conditions, the machining angle of the radii of curvature of the sixth lens and the seventh lens can be reduced, the machining formability of the sixth lens and the seventh lens is improved; the effective focal length of the sixth lens is also constrained, which is beneficial to the field angle design of the optical imaging system; it helps to improve the convergence ability of the optical imaging system, improve the imaging clarity of the optical imaging system, and also improve the matching degree of the edge field of view CRA and the chip CRA of the optical imaging system, and reduce the color cast risk.

[0048] In an example embodiment, the inner diameter d6sof the object side surface of the sixth spacer element, the radius of curvature R12of the image side surface of the sixth lens, and the radius of curvature R13of the object side surface of the seventh lens can satisfy -7 < d6s / (R12+R13) < 0, and the outer diameter D6mof the image side surface of the sixth spacer element, the radius of curvature R11of the object side surface of the sixth lens, and the radius of curvature R12of the image side surface of the sixth lens can satisfy 0 < D6m / (R11-R12) < 7. In an example, -5 < d6s / (R12+R13) < -2, and 2 < D6m / (R11-R12) < 4.5. By controlling the above conditional expressions, the inner diameter of the object side surface of the sixth spacer element and the outer diameter of the image side surface of the sixth spacer element can be constrained under the premise of guaranteeing the radii of curvature of the sixth lens and the seventh lens, stray light paths can be effectively blocked, the risk of stray light of the optical imaging system can be reduced, and the optical element group formed by the sixth lens, the sixth spacer element, and the seventh lens has a relatively stable step difference, while guaranteeing that the optical imaging system realizes small volume and high image quality.

[0049] In an example embodiment, the effective focal length f6of the sixth lens, the effective focal length f7of the seventh lens, the effective focal length f8of the eighth lens, the maximum thickness CP6of the sixth spacer element, the maximum thickness CP7of the seventh spacer element, and the interval EP67of the sixth spacer element and the seventh spacer element along the optical axis can satisfy -35 < (f6+f7+f8) / (CP6+EP67+CP7) < -5. In an example, -30 < (f6+f7+f8) / (CP6+EP67+CP7) < -12. By controlling the above conditional expressions, the smoothness and ease of molding of the effective surface (i.e., the aspherical surface for transmitting effective light rays) of the lens can be improved, it is guaranteed that the sixth lens, the seventh lens, and the eighth lens will not have a surface shape with a large degree of curvature, the assembly stability and imaging quality of the optical imaging system can be improved, and the probability of assembly deformation can be reduced; the maximum thickness of the sixth spacer element and the seventh spacer element can also be constrained while controlling the edge thickness of the seventh lens to improve the processing and molding properties of the seventh lens, assembly interference between adjacent two lenses in the sixth lens to the eighth lens can be avoided, and the field curvature of the optical imaging system can be adjusted.

[0050] In the example implementation, the inner diameter d3s of the object side surface of the third spacer element, the outer diameter D3m of the image side surface of the third spacer element, the effective focal length f3 of the third lens, the radius of curvature R7 of the object side surface of the fourth lens, and the radius of curvature R8 of the image side surface of the fourth lens can satisfy: -32mm < (R7-R8) x (d3s+D3m) / f3 < -5mm. In the example, -25mm < (R7-R8) x (d3s+D3m) / f3 < -14mm. By controlling the above conditional expression, the radii of curvature of the object side surface and the image side surface of the fourth lens and the effective focal length of the third lens can be constrained, so that the third lens and the fourth lens achieve the effect of converging light rays; at the same time, the inner diameter of the object side surface and the outer diameter of the image side surface of the third spacer element can be limited, effectively reducing feather stray light and corner white line stray light reflected by the inner diameter surface of the third spacer element, and making the optical element group formed by the third lens, the third spacer element, and the fourth lens have a relatively stable step, ensuring that the optical imaging system realizes small size and high image quality.

[0051] In the example implementation, the effective focal length f4 of the fourth lens, the effective focal length f5 of the fifth lens, and the interval EP45 of the fourth spacer element and the fifth spacer element along the optical axis can satisfy: 0mm < f5 x EP45 / f4 < 6mm, and the effective focal length f5 of the fifth lens, the effective focal length f6 of the sixth lens, and the interval EP56 of the fifth spacer element and the sixth spacer element along the optical axis can satisfy: 50 < (f5+f6) / EP56 < 160. In the example, 2mm < f5 x EP45 / f4 < 4mm. By controlling the above conditional expression, the effective focal lengths of the fourth lens, the fifth lens, and the sixth lens can be coordinated with the effective focal lengths of other lenses, which is conducive to achieving a relatively stable imaging focal plane position in the optical imaging system, ensuring the imaging stability of the optical imaging system during use; at the same time, the edge thickness of the fifth lens and the sixth lens can be limited, improving the processing and forming properties of the fifth lens and the sixth lens.

[0052] In the example implementation, the radius of curvature R7 of the object side surface of the fourth lens, the radius of curvature R9 of the object side surface of the fifth lens, and the inner diameter d4s of the object side surface of the fourth spacer element can satisfy: 6 < (R7+R9) / d4s < 25. In the example, 8 < (R7+R9) / d4s < 18. By controlling the above conditional expression, the light intake of the optical imaging system can be improved, and under the same light aperture, the relative luminance and the field of view angle of the optical imaging system can be improved; at the same time, the inner diameter of the object side surface of the fourth spacer element can be constrained, reducing cross-shaped stray light and trailing stray light reflected by the inner diameter surface of the fourth spacer element.

[0053] In an example embodiment, the curvature radius R8 of the image side surface of the fourth lens, the curvature radius R10 of the image side surface of the fifth lens, the inner diameter d4m of the image side surface of the fourth spacer element, and the outer diameter D5m of the image side surface of the fifth spacer element can satisfy: -14 < (R8-R10) / (D5m+d4m) < 0. In an example, -9 < (R8-R10) / (D5m+d4m) < -3. By controlling the above conditional expression, the large image surface of the optical imaging system can be realized while ensuring that the optical imaging system has a small volume; meanwhile, the inner diameter of the image side surface of the fourth spacer element and the outer diameter of the image side surface of the fifth spacer element can be constrained, thereby reducing the cross-shaped stray light and trailing stray light reflected by the inner diameter surfaces of the fourth spacer element and the fifth spacer element.

[0054] In an example embodiment, the outer diameter D4s of the object side surface of the fourth spacer element, the outer diameter D4m of the image side surface of the fourth spacer element, the maximum thickness CP4 of the fourth spacer element, the maximum thickness CP5 of the fifth spacer element, and the air gap T45 of the fourth lens and the fifth lens on the optical axis can satisfy: 2 < (D4s+D4m) / (CP4+T45+CP5) < 40. In an example, 9 < (D4s+D4m) / (CP4+T45+CP5) < 32. By controlling the above conditional expression, the central thickness of the fifth lens can be limited to a reasonable range, thereby reducing the risk of weld marks of the fifth lens during molding, and further reducing the stray light risk caused by the weld marks, and improving the cleanliness of the imaging of the optical imaging system; meanwhile, the maximum thickness of the fourth spacer element and the fifth spacer element can be constrained within a certain range, thereby avoiding assembly interference between adjacent two lenses in the fourth lens to the sixth lens, and facilitating adjustment of the field curvature of the optical imaging system, in addition, the overall design of the fourth spacer element can be optimized by controlling the outer diameters of the object side surface and the image side surface of the fourth spacer element.

[0055] In an example embodiment, the inner diameter d0s of the object side end surface of the lens barrel, the outer diameter D0s of the object side end surface of the lens barrel, the aperture number Fno of the optical imaging system, and the effective focal length f1 of the first lens can satisfy: 0 < (d0s+D0s) / f1xFno < 7. In an example, 2 < (d0s+D0s) / f1xFno < 5. By controlling the above conditional expression, the head design of the optical imaging system is facilitated, so that the optical imaging system satisfies the characteristics of a small head; meanwhile, the aperture number design of the optical imaging system can be facilitated, thereby improving the imaging quality of the optical imaging system.

[0056] In the example implementation, the effective focal length f4 of the fourth lens, the inner diameter d4s of the object side surface of the fourth spacer element, and the outer diameter D4s of the object side surface of the fourth spacer element can satisfy: 0 < f4 / (D4s-d4s) < 17. In an example, 4 < f4 / (D4s-d4s) < 14. By controlling the above conditional formula, the smoothness and easy formability of the effective surface (i.e., the aspherical surface for transmitting effective light) of the fourth lens can be improved, the surface shape with a large degree of bending of the fourth lens is ensured, and the imaging quality of the optical imaging system is improved; at the same time, the inner and outer diameters of the object side surface of the fourth spacer element are constrained, which is beneficial to improving the light blocking efficiency of the fourth spacer element and reducing the stray light risk of the optical imaging system.

[0057] In the example implementation, the effective focal length f5 of the fifth lens, the inner diameter d5s of the object side surface of the fifth spacer element, and the outer diameter D5s of the object side surface of the fifth spacer element can satisfy: 18 < f5 / (D5s-d5s) < 60. By controlling the above conditional formula, the surface shape with a large degree of bending of the fifth lens is ensured, the assembly stability of the optical imaging system is improved, and the probability of assembly deformation is reduced; at the same time, the inner and outer diameters of the object side surface of the fifth spacer element are constrained, which is beneficial to improving the light blocking efficiency of the fifth spacer element and reducing the stray light risk of the optical imaging system.

[0058] In the example implementation, the curvature radius R1 of the object side surface of the first lens, the curvature radius R2 of the image side surface of the first lens, the outer diameter D1s of the object side surface of the first spacer element, and the inner diameter d1m of the image side surface of the first spacer element can satisfy: 2 < (R1+R2) / (D1s-d1m) < 24. In an example, 7 < (R1+R2) / (D1s-d1m) < 18.5. By controlling the above conditional formula, the machining opening angle of the curvature radius of the first lens can be reduced, and the machining formability of the first lens is improved; at the same time, the outer diameter of the object side surface of the first spacer element and the inner diameter of the image side surface are constrained, which effectively improves the light blocking efficiency of the first spacer element and reduces the stray light risk of the optical imaging system.

[0059] In the example implementation, the curvature radius R3 of the object side surface of the second lens, the curvature radius R4 of the image side surface of the second lens, the inner diameter d2s of the object side surface of the second spacer element, the outer diameter D2m of the image side surface of the second spacer element, and the interval EP12 of the first spacer element and the second spacer element along the optical axis can satisfy: 12 < (R3 / R4) x (D2m+d2s) / EP12 < 40. By controlling the above conditional formula, the machining opening angle of the curvature radius of the second lens can be reduced, and the machining formability of the second lens is improved; at the same time, the inner diameter of the object side surface of the second spacer element and the outer diameter of the image side surface are constrained, which effectively improves the light blocking efficiency of the second spacer element and reduces the stray light risk of the optical imaging system.

[0060] In the exemplary embodiments, the optical imaging system can further include a diaphragm disposed between the object side and the first lens.

[0061] The optical imaging system according to the above embodiments of the present application can employ eight lenses and multiple spacer elements. By reasonably allocating the parameters of each lens and each spacer element, the risk of stray light of the optical imaging system can be reduced, the cleanliness of the imaging of the optical imaging system can be improved, and the optical imaging system can achieve a wider shooting range and higher imaging pixels in a smaller volume.

[0062] In the embodiments of the present application, at least one of the mirror surfaces of each of the first lens to the eighth lens is a non-spherical mirror surface. The non-spherical lens has the characteristic that the curvature continuously changes from the center of the lens to the periphery of the lens. Unlike the spherical lens which has a constant curvature from the center of the lens to the periphery of the lens, the non-spherical lens has a better curvature radius characteristic, has the advantages of improving the distortion aberration and improving the astigmatism aberration. After using the non-spherical lens, the aberration that occurs during imaging can be eliminated as much as possible, thereby improving the imaging quality. Alternatively, the object side surface and the image side surface of each of the first lens to the eighth lens are non-spherical mirror surfaces.

[0063] However, those skilled in the art should understand that the number of lenses and spacer elements constituting the optical imaging system can be changed without departing from the technical solutions claimed by the present application, to obtain the various results and advantages described in the present specification.

[0064] The specific embodiments of the optical imaging system applicable to the above embodiments are further described below with reference to the accompanying drawings.

[0065] First embodiment

[0066] The following refers to Figures 2 to 5D The optical imaging system according to the first embodiment of the present application is described. Figure 2 A structural schematic diagram of the optical imaging system 110 according to embodiment 1 of the first embodiment of the present application is shown; Figure 3 A structural schematic diagram of the optical imaging system 120 according to embodiment 2 of the first embodiment of the present application is shown; Figure 4 A structural schematic diagram of the optical imaging system 130 according to embodiment 3 of the first embodiment of the present application is shown.

[0067] As Figures 2 to 4As shown, the optical imaging system 110, 120, 130 each includes a lens barrel P0, and an eight-piece lens group and a spacer element group disposed within the lens barrel P0. The eight-piece lens group includes, in order from the object side to the image side, a first lens E1, a second lens E2, a third lens E3, a fourth lens E4, a fifth lens E5, a sixth lens E6, a seventh lens E7, and an eighth lens E8. A stop STO can be disposed between the object side and the first lens E1. The spacer element group includes a first spacer element P1, a second spacer element P2, a third spacer element P3, a fourth spacer element P4, a fifth spacer element P5, a sixth spacer element P6, and a seventh spacer element P7. The spacer elements can block extra light rays during the imaging process from entering the next lens, so that the lens and the lens barrel P0 are better supported, and the structural stability of the optical imaging system is enhanced.

[0068] The first lens E1 has positive refractive power, with a convex object side surface S1 and a concave image side surface S2. The second lens E2 has positive refractive power, with a convex object side surface S3 and a concave image side surface S4. The third lens E3 has negative refractive power, with a convex object side surface S5 and a concave image side surface S6. The fourth lens E4 has positive refractive power, with a convex object side surface S7 and a convex image side surface S8. The fifth lens E5 has positive refractive power, with a convex object side surface S9 and a concave image side surface S10. The sixth lens E6 has negative refractive power, with a concave object side surface S11 and a convex image side surface S12. The seventh lens E7 has positive refractive power, with a convex object side surface S13 and a concave image side surface S14. The eighth lens E8 has negative refractive power, with a convex object side surface S15 and a concave image side surface S16. 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-S18 in order and is ultimately imaged on an image plane S19 (not shown).

[0069] Table 1 shows a basic parameter table of the optical imaging system of the first embodiment, where the units of the radius of curvature, the thickness / distance, and the focal length are all millimeters (mm).

[0070]

[0071]

[0072] Table 1

[0073] In the present embodiment, the total effective focal length f of the optical imaging system has a value of 6.29 mm, the half of the maximum field of view angle Semi-FOV of the optical imaging system has a value of 41.38°, and the F-number Fno of the optical imaging system has a value of 1.83.

[0074] In the first embodiment, the object side surface and the image side surface of any one of the first lens E1 to the eighth lens E8 are aspherical surfaces, and the surface shape x of each aspherical surface can be defined by, but not limited to, the following aspherical surface formula:

[0075]

[0076] wherein x is the sag of the aspherical surface at a position along the optical axis at a height h from the vertex of the aspherical surface; c is the paraxial curvature of the aspherical surface, c = 1 / R (i.e., the paraxial curvature c is the inverse of the curvature radius R in Table 1); k is the conic coefficient; and Ai is the correction coefficient of the i-th order of the aspherical surface. Table 2 gives the high-order coefficients A4, A6, A8, A10 and A12 of the aspherical surfaces S1-S16 that can be used in the first embodiment. 10 12 14 16 18 20 22 24 26 28 30 .

[0077]

[0078]

[0079] Table 2

[0080] Figure 5A Figures 6A, 6B and 6C show the on-axis chromatic aberration curves of the optical imaging systems 110, 120 and 130 of the first embodiment, which represent the deviation of the converging focal points of light rays of different wavelengths via the optical imaging systems 110, 120 and 130. Figure 5B Figures 7A, 7B and 7C show the astigmatism curves of the optical imaging systems 110, 120 and 130 of the first embodiment, which represent the meridional image surface curvature and the sagittal image surface curvature corresponding to different image heights. Figure 5C Figures 8A, 8B and 8C show the distortion curves of the optical imaging systems 110, 120 and 130 of the first embodiment, which represent the distortion size values corresponding to different image heights. Figure 5D Figures 9A, 9B and 9C show the magnification chromatic aberration curves of the optical imaging systems 110, 120 and 130 of the first embodiment, which represent the deviation of the image heights on the imaging plane after the light rays pass through the systems. According to the magnification chromatic aberration curves, the optical imaging systems 110, 120 and 130 of the first embodiment can achieve good imaging quality. Figures 5A to 5D Figures 9A, 9B and 9C show the magnification chromatic aberration curves of the optical imaging systems 110, 120 and 130 of the first embodiment, which represent the deviation of the image heights on the imaging plane after the light rays pass through the systems. According to the magnification chromatic aberration curves, the optical imaging systems 110, 120 and 130 of the first embodiment can achieve good imaging quality.

[0081] Second embodiment

[0082] The following will be described with reference to​​​​​​​​​​Figures 6 to 9D An optical imaging system according to the second embodiment of the present application is described. Figure 6 A structural schematic diagram of the optical imaging system 210 according to the first embodiment of the second embodiment of the present application is shown; Figure 7 A structural schematic diagram of the optical imaging system 220 according to the second embodiment of the present application is shown; Figure 8 A structural schematic diagram of the optical imaging system 230 according to the third embodiment of the second embodiment of the present application is shown.

[0083] As shown in Figures 6 to 8 The optical imaging systems 210, 220, 230 all include a lens barrel P0, and an eight-piece lens group and a spacer element group disposed in the lens barrel P0. The eight-piece lens group includes, in order from the object side to the image side, a first lens E1, a second lens E2, a third lens E3, a fourth lens E4, a fifth lens E5, a sixth lens E6, a seventh lens E7, and an eighth lens E8. A stop STO can be disposed between the object side and the first lens E1. The spacer element group includes a first spacer element P1, a second spacer element P2, a third spacer element P3, a fourth spacer element P4, a fifth spacer element P5, a sixth spacer element P6, and a seventh spacer element P7. The spacer elements can block excess light rays in the imaging process from entering the next lens, so that the lens and the lens barrel P0 are better supported, enhancing the structural stability of the optical imaging system.

[0084] The first lens E1 has positive refractive power, with a convex object side surface S1 and a concave image side surface S2. The second lens E2 has negative refractive power, with a convex object side surface S3 and a concave image side surface S4. The third lens E3 has negative refractive power, with a concave object side surface S5 and a convex image side surface S6. The fourth lens E4 has positive refractive power, with a convex object side surface S7 and a convex image side surface S8. The fifth lens E5 has positive refractive power, with a convex object side surface S9 and a concave image side surface S10. The sixth lens E6 has negative refractive power, with a concave object side surface S11 and a convex image side surface S12. The seventh lens E7 has positive refractive power, with a convex object side surface S13 and a convex image side surface S14. The eighth lens E8 has negative refractive power, with a convex object side surface S15 and a concave image side surface S16. 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 order and is ultimately imaged on an imaging surface S19 (not shown).

[0085] Table 3 shows a table of basic parameters of the optical imaging system of the second embodiment, where the units of the radius of curvature, thickness / distance, and focal length are all millimeters (mm).

[0086]

[0087] Table 3

[0088] In this embodiment, the total effective focal length f of the optical imaging system is 8.14 mm, the value of half of the maximum field of view (Semi-FOV) of the optical imaging system is 40.57°, and the value of the aperture number Fno of the optical imaging system is 1.83.

[0089] In the second embodiment, the object-side surface and image-side surface of any one of the first lens E1 to the eighth lens E8 are aspherical. Table 4 shows the higher-order coefficients A4, A6, A8, and A6 that can be used for each aspherical mirror S1-S16 in the second embodiment. 10 A 12 A 14 A 16 A 18 and A 20 .

[0090]

[0091]

[0092] Table 4

[0093] Figure 9A The on-axis chromatic aberration curves of the optical imaging systems 210, 220 and 230 of the second embodiment are shown, which represent the deflection of the focal point after light of different wavelengths passes through the optical imaging systems 210, 220 and 230. Figure 9B Astigmatism curves of optical imaging systems 210, 220, and 230 according to the second embodiment are shown, which represent the meridional image plane curvature and sagittal image plane curvature corresponding to different image heights. Figure 9C The distortion curves of the optical imaging systems 210, 220 and 230 of the second embodiment are shown, which represent the distortion magnitude values ​​corresponding to different image heights. Figure 9D The magnification chromatic aberration curves of the optical imaging systems 210, 220, and 230 of the second embodiment are shown, representing the deviations in image height at different points on the imaging plane after light passes through the system. According to Figures 9A to 9D It can be seen that the optical imaging systems 210, 220 and 230 of the second embodiment can achieve good imaging quality.

[0094] Third embodiment

[0095] The following is for reference Figures 10 to 13D This application describes an optical imaging system according to a third embodiment. Figure 10 A schematic diagram of the structure of an optical imaging system 310 according to Embodiment 1 of the third embodiment of this application is shown; Figure 11 A schematic diagram of the structure of an optical imaging system 320 according to Embodiment 2 of the third embodiment of this application is shown; Figure 12A structural diagram of the optical imaging system 330 according to Embodiment 3 of the third embodiment of the present application is shown.

[0096] As shown in Figures 10 to 12 , the optical imaging systems 310, 320, and 330 each include a lens barrel P0, and an eight-piece lens group and a spacer element group disposed in the lens barrel P0. The eight-piece lens group includes, in order from the object side to the image side, a first lens E1, a second lens E2, a third lens E3, a fourth lens E4, a fifth lens E5, a sixth lens E6, a seventh lens E7, and an eighth lens E8. A stop STO can be disposed between the object side and the first lens E1. The spacer element group includes a first spacer element P1, a second spacer element P2, a third spacer element P3, a fourth spacer element P4, a fifth spacer element P5, a sixth spacer element P6, and a seventh spacer element P7. The spacer elements can block excess light rays in the imaging process from entering the next lens, so that the lens and the lens barrel P0 are better supported, enhancing the structural stability of the optical imaging system.

[0097] The first lens E1 has positive refractive power, with a convex object side surface S1 and a concave image side surface S2. The second lens E2 has negative refractive power, with a convex object side surface S3 and a concave image side surface S4. The third lens E3 has negative refractive power, with a concave object side surface S5 and a concave image side surface S6. The fourth lens E4 has positive refractive power, with a convex object side surface S7 and a convex image side surface S8. The fifth lens E5 has positive refractive power, with a convex object side surface S9 and a concave image side surface S10. The sixth lens E6 has negative refractive power, with a concave object side surface S11 and a convex image side surface S12. The seventh lens E7 has positive refractive power, with a convex object side surface S13 and a concave image side surface S14. The eighth lens E8 has negative refractive power, with a convex object side surface S15 and a concave image side surface S16. 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 order and is ultimately imaged on an imaging surface S19 (not shown).

[0098] Table 5 shows a table of basic parameters of the optical imaging system of the third embodiment, where the units of the radius of curvature, the thickness / distance, and the focal length are all millimeters (mm).

[0099]

[0100] Table 5

[0101] In this embodiment, the value of the total effective focal length f of the optical imaging system is 8.55 mm, the value of the half of the maximum field of view angle Semi-FOV of the optical imaging system is 37.04°, and the value of the F-number Fno of the optical imaging system is 1.83.

[0102] In the third embodiment, the object-side surface and image-side surface of any one of the first lens E1 to the eighth lens E8 are aspherical. Table 6 gives the higher-order coefficients A4, A6, A8, and A6 that can be used for each aspherical mirror S1-S16 in the third embodiment. 10 A 12 A 14 A 16 A 18 and A 20 .

[0103]

[0104]

[0105] Table 6

[0106] Figure 13A The on-axis chromatic aberration curves of the optical imaging systems 310, 320 and 330 of the third embodiment are shown, which represent the deflection of the focal point after light of different wavelengths passes through the optical imaging systems 310, 320 and 330. Figure 13B Astigmatism curves of optical imaging systems 310, 320, and 330 according to the third embodiment are shown, representing the meridional and sagittal image plane curvatures corresponding to different image heights. Figure 13C The distortion curves of the optical imaging systems 310, 320 and 330 of the third embodiment are shown, which represent the distortion magnitude values ​​corresponding to different image heights. Figure 13D The magnification chromatic aberration curves of the optical imaging systems 310, 320, and 330 of the third embodiment are shown, representing the deviations in image height at different points on the imaging plane after light passes through the system. According to Figures 13A to 13D It can be seen that the optical imaging systems 310, 320 and 330 of the third embodiment can achieve good imaging quality.

[0107] Table 7 lists some basic parameters of the lens barrel P0 and spacer elements in each embodiment from the first to the third embodiment, such as d1m, D1s, d2s, D2m, d3s, D3m, d4s, d4m, D4s, D4m, d5s, D5s, D5m, d6s, D6m, d7s, d7m, D7s, D7m, d0s, D0s, EP12, CP4, EP45, CP5, EP56, CP6, EP67, CP7, and L. The basic parameters listed in Table 7 are... Figure 1 The measurements were obtained using the annotation method shown, and the units of the basic parameters listed in Table 7 are all millimeters (mm).

[0108]

[0109]

[0110] Table 7

[0111] In summary, the conditional expressions of each embodiment in the first to third embodiments satisfy the relationship shown in Table 8.

[0112] Conditional expression / embodiment 1-1 1-2 1-3 2-1 2-2 2-3 3-1 3-2 3-3 (d7m+D7m) / (R15-R16) 27.45 27.29 27.00 10.61 10.47 10.45 12.57 12.76 12.37 tan(Semi-FOV) x (f-f8) / L 3.09 2.98 3.03 1.51 1.47 1.54 1.33 1.29 1.29 (d7s / CP7+D7s / CT8) / f7 x T78 31.95 30.20 21.77 57.35 54.83 49.20 32.49 28.53 29.99 R12 / R11 2.00 2.00 2.00 1.70 1.70 1.70 1.93 1.93 1.93 R13 / R12 -0.62 -0.62 -0.62 -0.76 -0.76 -0.76 -0.63 -0.63 -0.63 d6s / (R12+R13) -2.27 -2.28 -2.33 -4.57 -4.55 -4.50 -2.63 -2.60 -2.64 D6m / (R11-R12) 3.52 3.45 3.41 3.80 3.90 3.91 3.19 3.24 3.22 (f6+f7+f8) / (CP6+EP67+CP7) -29.63 -28.98 -27.01 -12.80 -13.66 -12.40 -11.88 -12.32 -12.25 (R7-R8) x (d3s+D3m) / f3 -19.74 -17.68 -20.18 -23.82 -20.89 -21.23 -15.70 -14.04 -14.71 f5 x EP45 / f4 2.80 3.30 2.63 3.45 3.75 3.32 3.14 3.38 3.01 (f5+f6) / EP56 67.56 73.06 67.76 153.27 148.62 144.18 60.06 58.63 57.07 (R7+R9) / d4s 8.71 8.56 8.04 17.69 17.28 16.52 14.58 14.36 14.56 (R8-R10) / (D5m+d4m) -3.57 -3.53 -3.71 -4.42 -4.36 -4.66 -7.97 -8.10 -8.55 (D4s+D4m) / (CP4+T45+CP5) 9.17 10.64 22.27 13.36 13.89 28.07 16.91 17.62 31.74 (d0s+D0s) / f1 x Fno 2.56 3.06 2.61 3.63 4.04 3.28 3.67 4.10 3.75 f4 / (D4s-d4s) 13.55 6.32 4.44 8.59 9.53 8.33 10.60 12.06 8.66 f5 / (D5s-d5s) 24.46 23.57 21.87 49.03 46.65 44.85 54.47 50.79 51.80 (R1+R2) / (D1s-d1m) 7.83 14.69 7.24 9.09 17.40 14.24 10.67 18.39 13.70 (R3 / R4) x (D2m+d2s) / EP12 19.67 17.95 19.87 35.65 26.31 33.65 32.49 33.76 34.22

[0113] Table 8

[0114] The present application also provides an imaging device, the electronic photosensitive element of which can be a charge-coupled device (CCD) or a complementary metal-oxide-semiconductor device (CMOS). The imaging device can be a stand-alone imaging apparatus such as a digital camera, or an imaging module integrated on a mobile electronic device such as a mobile phone. The imaging device is equipped with the optical imaging system described above.

[0115] The above description is merely preferred embodiments of the present application and a description of the technical principles of the application. It should be understood by those skilled in the art that the scope of the application disclosed in the present application is not limited to the technical solutions formed by the specific combinations of the technical features described above, and should also cover other technical solutions formed by any combinations of the technical features described above or their equivalent features without departing from the inventive concept. For example, the technical solutions formed by the mutual replacement of the above-described features and the technical features disclosed in the present application (but not limited to) having similar functions.

Claims

1. An optical imaging system, characterized in that, include: An eight-element lens group, consisting of the following elements sequentially along the optical axis from the object side to the image side: The first lens has an effective focal length greater than zero, and the radii of curvature of both the object-side and image-side surfaces are greater than zero. The second lens has a radius of curvature greater than zero for both its object-side and image-side surfaces. The third lens has an effective focal length of less than zero; The fourth lens has an effective focal length greater than zero, a radius of curvature of the object side greater than zero, and a radius of curvature of the image side less than zero. The fifth lens has an effective focal length greater than zero, and the radii of curvature of both the object-side and image-side surfaces are greater than zero. The sixth lens has an effective focal length of less than zero, and the radii of curvature of both the object-side and image-side surfaces are less than zero. The seventh lens has an effective focal length greater than zero and a radius of curvature of the object side surface greater than zero. The eighth lens has an effective focal length of less than zero and radii of curvature of both the object-side and image-side surfaces greater than zero. A group of spacers, including a seventh spacer abutting the image-side surface of the seventh lens; and The lens barrel, the eight-element lens group, and the spacer element group are placed inside the lens barrel. The optical imaging system has eight lenses with optical power. The inner diameter d7m of the image-side surface of the seventh spacer element, the outer diameter D7m of the image-side surface of the seventh spacer element, the radius of curvature R15 of the object-side surface of the eighth lens, and the radius of curvature R16 of the image-side surface of the eighth lens satisfy: 10.45≤(d7m+D7m) / (R15-R16)≤27.45, and The maximum field of view (Semi-FOV) of the optical imaging system, the total effective focal length (f) of the optical imaging system, the effective focal length (f8) of the eighth lens, and the length (L) of the lens barrel in the direction of the optical axis satisfy the following condition: 1.29 ≤ tan(Semi-FOV) × (f - f8) / L ≤ 3.

09.

2. The optical imaging system according to claim 1, characterized in that, The effective focal length f7 of the seventh lens, the air gap T78 between the seventh and eighth lenses on the optical axis, the center thickness CT8 of the eighth lens on the optical axis, the inner diameter d7s of the object side surface of the seventh spacer element, the outer diameter D7s of the object side surface of the seventh spacer element, and the maximum thickness CP7 of the seventh spacer element satisfy: 21.77≤(d7s / CP7+D7s / CT8) / f7×T78≤57.

35.

3. The optical imaging system according to claim 1, characterized in that, The radius of curvature R11 of the object side of the sixth lens and the radius of curvature R12 of the image side of the sixth lens satisfy: 1.70≤R12 / R11≤2.00, and the radius of curvature R12 of the image side of the sixth lens and the radius of curvature R13 of the object side of the seventh lens satisfy: -0.76≤R13 / R12≤-0.

62.

4. The optical imaging system according to claim 3, characterized in that, The spacer element group further includes a sixth spacer element that rests against the image side of the sixth lens. Wherein, the inner diameter d6s of the object-side surface of the sixth spacer element, the radius of curvature R12 of the image-side surface of the sixth lens, and the radius of curvature R13 of the object-side surface of the seventh lens satisfy: -4.57≤d6s / (R12+R13)≤-2.27, and The outer diameter D6m of the image side of the sixth spacer element, the radius of curvature R11 of the object side of the sixth lens, and the radius of curvature R12 of the image side of the sixth lens satisfy: 3.19≤D6m / (R11-R12)≤3.

91.

5. The optical imaging system according to claim 1, characterized in that, The spacer element group further includes a sixth spacer element that rests against the image side of the sixth lens. Wherein, the effective focal length f6 of the sixth lens, the effective focal length f7 of the seventh lens, the effective focal length f8 of the eighth lens, the maximum thickness CP6 of the sixth spacer element, the maximum thickness CP7 of the seventh spacer element, and the spacing EP67 of the sixth and seventh spacers along the optical axis satisfy: -29.63≤(f6+f7+f8) / (CP6+EP67+CP7)≤-11.

88.

6. The optical imaging system according to claim 1, characterized in that, The spacer element group further includes a third spacer element that rests against the image-side surface of the third lens. Wherein, the inner diameter d3s of the object side of the third spacer element, the outer diameter D3m of the image side of the third spacer element, the effective focal length f3 of the third lens, the radius of curvature R7 of the object side of the fourth lens, and the radius of curvature R8 of the image side of the fourth lens satisfy: -23.82mm≤(R7-R8)×(d3s+D3m) / f3≤-14.04mm.

7. The optical imaging system according to claim 1, characterized in that, The spacer element group further includes a fourth spacer element resting on the image-side surface of the fourth lens, a fifth spacer element resting on the image-side surface of the fifth lens, and a sixth spacer element resting on the image-side surface of the sixth lens. Wherein, the effective focal length f4 of the fourth lens, the effective focal length f5 of the fifth lens, and the spacing EP45 of the fourth and fifth spacer elements along the optical axis satisfy: 2.63mm ≤ f5 × EP45 / f4 ≤ 3.75mm, and The effective focal length f5 of the fifth lens, the effective focal length f6 of the sixth lens, and the spacing EP56 of the fifth and sixth spacers along the optical axis satisfy: 57.07≤(f5+f6) / EP56≤153.

27.

8. The optical imaging system according to claim 1, characterized in that, The spacer element group further includes a fourth spacer element that rests against the image side of the fourth lens. Wherein, the radius of curvature R7 of the object side surface of the fourth lens, the radius of curvature R9 of the object side surface of the fifth lens, and the inner diameter d4s of the object side surface of the fourth spacer element satisfy: 8<(R7+R9) / d4s≤17.

69.

9. The optical imaging system according to claim 1, characterized in that, The spacer element group further includes a fourth spacer element abutting the image-side surface of the fourth lens and a fifth spacer element abutting the image-side surface of the fifth lens. Wherein, the radius of curvature R8 of the image side of the fourth lens, the radius of curvature R10 of the image side of the fifth lens, the inner diameter d4m of the image side of the fourth spacer element, and the outer diameter D5m of the image side of the fifth spacer element satisfy: -8.55≤(R8-R10) / (D5m+d4m)≤-3.

53.

10. The optical imaging system according to claim 1, characterized in that, The spacer element group further includes a fourth spacer element abutting the image-side surface of the fourth lens and a fifth spacer element abutting the image-side surface of the fifth lens. Wherein, the outer diameter D4s of the object side of the fourth spacer element, the outer diameter D4m of the image side of the fourth spacer element, the maximum thickness CP4 of the fourth spacer element, the maximum thickness CP5 of the fifth spacer element, and the air gap T45 between the fourth lens and the fifth lens on the optical axis satisfy: 9.17≤(D4s+D4m) / (CP4+T45+CP5)≤31.

74.

11. The optical imaging system according to any one of claims 1 to 10, characterized in that, The inner diameter d0s of the object-side end face of the lens barrel, the outer diameter D0s of the object-side end face of the lens barrel, the aperture number Fno of the optical imaging system and the effective focal length f1 of the first lens satisfy: 2.56≤(d0s+D0s) / f1×Fno≤4.

10.

12. The optical imaging system according to any one of claims 1 to 10, characterized in that, The spacer element group further includes a fourth spacer element that rests against the image side of the fourth lens. Wherein, the effective focal length f4 of the fourth lens, the inner diameter d4s of the object side of the fourth spacer element and the outer diameter D4s of the object side of the fourth spacer element satisfy: 4.44≤f4 / (D4s-d4s)≤13.

55.

13. The optical imaging system according to any one of claims 1 to 10, characterized in that, The spacer element group further includes a fifth spacer element that rests against the image-side surface of the fifth lens. Wherein, the effective focal length f5 of the fifth lens, the inner diameter d5s of the object side of the fifth spacer element and the outer diameter D5s of the object side of the fifth spacer element satisfy: 21.87≤f5 / (D5s-d5s)≤54.

47.

14. The optical imaging system according to any one of claims 1 to 10, characterized in that, The spacer element group further includes a first spacer element that rests against the image side of the first lens. Wherein, the radius of curvature R1 of the object side of the first lens, the radius of curvature R2 of the image side of the first lens, the outer diameter D1s of the object side of the first spacer element and the inner diameter d1m of the image side of the first spacer element satisfy: 7.24≤(R1+R2) / (D1s-d1m)≤18.

39.

15. The optical imaging system according to any one of claims 1 to 10, characterized in that, The spacer element group further includes a first spacer element that rests against the image side of the first lens and a second spacer element that rests against the image side of the second lens. Wherein, the radius of curvature R3 of the object side of the second lens, the radius of curvature R4 of the image side of the second lens, the inner diameter d2s of the object side of the second spacer, the outer diameter D2m of the image side of the second spacer, and the spacing EP12 of the first spacer and the second spacer along the optical axis satisfy: 17.95≤(R3 / R4)×(D2m+d2s) / EP12≤35.65.

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