Optical system, camera module and electronic device

Abstract

The present invention relates to an optical system, a camera module and an electronic device. The optical system includes, from the object side to the image side, in sequence: a first lens with positive refractive power, the object side of the lens is convex at the optical axis, and the image side is concave at the optical axis; a second lens with negative refractive power, the object side of the lens is convex at the optical axis, and the image side is concave at the optical axis; a third lens with refractive power; a fourth lens, a fifth lens, and a sixth lens with refractive power; a seventh lens with positive refractive power, the object side of the lens is convex at the optical axis, and the image side is concave at the optical axis; an eighth lens with negative refractive power, the image side of the lens is concave at the optical axis; the optical system satisfies the relationship: 0.2<DL / Imgh<0.5; wherein DL is the aperture size of the diaphragm, and Imgh is the diagonal length of the effective imaging area of ​​the optical system on the imaging plane. The above optical system can effectively improve the shooting quality of the system in a dark light environment.

Description

Technical Field

[0001] The present invention relates to the field of photography, and in particular to an optical system, a photography module and an electronic device. Background Art

[0002] With the widespread use of electronic products such as smartphones, tablets, drones, and computers in our lives, the camera performance of electronic products has become one of the key points that users pay attention to when choosing products. In addition, the performance of photosensitive elements has been improved along with technological progress, which has made it possible to further improve the shooting quality. In particular, with the increasing demand for shooting dark scenes such as night scenes and starry skies, whether the optical system can cooperate with the photosensitive elements to shoot clear pictures in dark environments has become one of the key factors for improving the shooting quality of current cameras. Summary of the invention

[0003] Based on this, it is necessary to provide an optical system, a camera module and an electronic device to improve the shooting quality in a dark environment.

[0004] An optical system, comprising, from the object side to the image side, the following:

[0005] A first lens having positive refractive power, wherein the object side surface of the first lens is convex at the optical axis, and the image side surface of the first lens is concave at the optical axis;

[0006] a second lens having negative refractive power, wherein the object-side surface of the second lens is convex at the optical axis, and the image-side surface of the second lens is concave at the optical axis;

[0007] a third lens having refractive power;

[0008] a fourth lens having a refractive power;

[0009] a fifth lens having refractive power;

[0010] a sixth lens element having negative refractive power;

[0011] a seventh lens having positive refractive power, wherein the object-side surface of the seventh lens is convex at the optical axis, and the image-side surface of the seventh lens is concave at the optical axis;

[0012] an eighth lens having negative refractive power, wherein the image side surface of the eighth lens is concave at the optical axis;

[0013] The optical system satisfies the following relationship:

[0014] 0.2<DL / Imgh<0.5;

[0015] Wherein, DL is the aperture size of the optical system, and Imgh is the diagonal length of the effective imaging area of ​​the optical system on the imaging plane.

[0016] The aperture size of the system determines the amount of light passing through the entire system, while the size of the imaging surface determines the pixel size and picture clarity of the entire system. The reasonable combination of the two can ensure that the system has a reasonable amount of light passing through to ensure the clarity of the shooting. When the optical system satisfies the refractive power, surface shape and conditional relationship of the above-mentioned lens, the light passing through the optical system and the size of the imaging surface can be reasonably configured, thereby effectively improving the shooting quality of the system in a dark light environment. When DL / Imgh>0.5, the system will be overexposed and the brightness will be too high, which will eventually affect the picture quality; when DL / Imgh<0.2, the system will have insufficient light passing through and the relative brightness of the light will be insufficient, resulting in a decrease in picture clarity.

[0017] In one embodiment, the optical system satisfies the following relationship:

[0018] 0<sin(FOV) / TTL<0.2;

[0019] Wherein, FOV is the maximum field of view of the optical system, TTL is the distance from the object side of the first lens to the imaging surface of the optical system on the optical axis, and the unit of TTL is mm. When the above relationship is met, the optical system can simultaneously meet the requirements of miniaturization and shooting of a wide range of scenes, while also meeting the requirements of high-definition shooting. When sin(FOV) / TTL>0.2, the structure of the system is too compact, and it is difficult to correct aberrations, resulting in a decrease in imaging performance; when SIN(FOV) / TTL<0, the structure of the system will be too long, making it difficult to meet the requirements of miniaturization design.

[0020] In one embodiment, the optical system satisfies the following relationship:

[0021] Fno / TTL<0.5;

[0022] Wherein, Fno is the aperture number of the optical system, TTL is the distance from the object side of the first lens to the imaging surface of the optical system on the optical axis, and the unit of TTL is mm. When the above relationship is satisfied, the optical system can take into account the design requirements of large aperture and miniaturization at the same time, provide sufficient light flux for shooting, and meet the needs of high-quality and high-definition shooting. When Fno / TTL>0.5, the system will cause insufficient light flux while taking into account miniaturization, resulting in a decrease in the clarity of the captured image.

[0023] In one embodiment, the optical system satisfies the following relationship:

[0024] 0.1≤BFL / TTL<0.4;

[0025] Wherein, BFL is the shortest distance from the image side of the eighth lens to the imaging plane of the optical system in the direction parallel to the optical axis, and TTL is the distance from the object side of the first lens to the imaging plane of the optical system on the optical axis. When the above relationship is met, it can be ensured that the system has a sufficient focusing range to improve the assembly yield of the module, and at the same time ensure that the system has a large focal depth to obtain more depth information on the object side.

[0026] In one embodiment, the optical system satisfies the following relationship:

[0027] -4<f6 / f7<0;

[0028] Wherein, f6 is the effective focal length of the sixth lens, and f7 is the effective focal length of the seventh lens. The sixth lens provides negative refractive power to diverge the light to meet the image height requirement, while the seventh lens provides positive refractive power to facilitate light convergence. When the above relationship is met, the refractive power of the two will be reasonably distributed, which can not only effectively compress the system volume and achieve the miniaturization design requirements, but also can well correct the aberration and field curvature of the entire optical system.

[0029] In one embodiment, the optical system satisfies the following relationship:

[0030] 0.2<DL / TTL<1;

[0031] Wherein, DL is the aperture size of the optical system, and TTL is the distance from the object side of the first lens to the imaging surface of the optical system on the optical axis. When the above relationship is met, the miniaturized design of the system can be guaranteed, and the amount of light required for the system shooting can be provided to achieve high-quality and high-definition shooting effects. When DL / TTL>1, the aperture of the aperture will be too large when the system meets the miniaturized design, causing the edge light to enter the system, thereby reducing the imaging quality; when DL / TTL<0.2, the aperture of the aperture will be too small when the system meets the miniaturized design, thereby failing to meet the light throughput requirements of the system and failing to achieve high-definition shooting requirements in dark environments.

[0032] In one embodiment, the optical system satisfies the following relationship:

[0033] TTL / Imgh<1;

[0034] Wherein, TTL is the distance from the object side of the first lens to the imaging surface of the optical system on the optical axis, and Imgh is the diagonal length of the effective imaging area of ​​the optical system on the imaging surface. When the above relationship is satisfied, the optical system can take into account both miniaturization design and high-definition shooting. When TTL / Imgh>1, the system cannot guarantee high-definition imaging effect while achieving miniaturization.

[0035] In one embodiment, the optical system satisfies the following relationship:

[0036] 1.0<TTL / f<2.0;

[0037] Wherein, TTL is the distance from the object side of the first lens to the imaging surface of the optical system on the optical axis, and f is the effective focal length of the optical system. When the above relationship is satisfied, the effective focal length and the total optical length of the optical system will be reasonably configured, which can not only realize the miniaturized design, but also ensure that the light is better converged on the imaging surface of the system, thereby helping to improve the imaging quality and ensure the authenticity of the image. When TTL / f≤1.0, the optical length of the system is too short, which will increase the sensitivity of the system and is not conducive to the convergence of light on the imaging surface; when TTL / f≥2, the optical length of the system is too long, which will cause the main light angle when the light enters the imaging surface to be too large, so that the edge light cannot be imaged on the imaging surface, and then the imaging information is incomplete.

[0038] In one embodiment, the optical system satisfies the following relationship:

[0039] 0<R11 / R12<3.5;

[0040] Wherein, R11 is the curvature radius of the object side surface of the sixth lens at the optical axis, and R12 is the curvature radius of the image side surface of the sixth lens at the optical axis. When the above relationship is satisfied, the curvature radii of the object side surface and the image side surface of the sixth lens can be appropriately configured, which is beneficial to reduce the sensitivity of the system and improve the molding yield.

[0041] A camera module comprises a photosensitive element and the optical system described in any one of the above embodiments, wherein the photosensitive element is arranged on the image side of the optical system. By adopting the above optical system, the camera module can have excellent camera quality. By adopting the above optical system, the light flux of the system and the photosensitive surface size of the photosensitive element can be reasonably configured, thereby effectively improving the shooting quality of the module in a dark light environment.

[0042] An electronic device comprises a fixing part and the camera module, wherein the camera module is arranged on the fixing part. By adopting the camera module, the electronic device can have an excellent shooting function. By adopting the camera module, the electronic device can also have excellent shooting quality when shooting dark scenes such as night scenes and starry sky. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] Figure 1 A schematic diagram of an optical system provided in accordance with the first embodiment of the present application;

[0044] Figure 2 : are the longitudinal spherical aberration diagram (mm), astigmatism diagram (mm) and distortion diagram (%) of the optical system in the first embodiment;

[0045] Figure 3 A schematic diagram of an optical system provided for a second embodiment of the present application;

[0046] Figure 4 : are longitudinal spherical aberration diagram (mm), astigmatism diagram (mm) and distortion diagram (%) of the optical system in the second embodiment;

[0047] Figure 5 A schematic diagram of an optical system provided in accordance with a third embodiment of the present application;

[0048] Figure 6 : are longitudinal spherical aberration diagram (mm), astigmatism diagram (mm) and distortion diagram (%) of the optical system in the third embodiment;

[0049] Figure 7 A schematic diagram of an optical system provided in accordance with a fourth embodiment of the present application;

[0050] Figure 8 : are longitudinal spherical aberration diagram (mm), astigmatism diagram (mm) and distortion diagram (%) of the optical system in the fourth embodiment;

[0051] Fig. 9 A schematic diagram of an optical system provided in accordance with a fifth embodiment of the present application;

[0052] Fig.10 : are longitudinal spherical aberration diagram (mm), astigmatism diagram (mm) and distortion diagram (%) of the optical system in the fifth embodiment;

[0053] Fig.11 A schematic diagram of an optical system provided in accordance with a sixth embodiment of the present application;

[0054] Fig.12 : are longitudinal spherical aberration diagram (mm), astigmatism diagram (mm) and distortion diagram (%) of the optical system in the sixth embodiment;

[0055] Fig.13 A schematic diagram of an optical system provided in a seventh embodiment of the present application;

[0056] Fig.14 : are longitudinal spherical aberration diagram (mm), astigmatism diagram (mm) and distortion diagram (%) of the optical system in the seventh embodiment;

[0057] Fig.15 A schematic diagram of a camera module provided in one embodiment of the present application;

[0058] Fig.16 A schematic diagram of an electronic device provided in accordance with an embodiment of the present application. DETAILED DESCRIPTION

[0059] In order to facilitate understanding of the present invention, the present invention will be described more fully below with reference to the relevant drawings. The preferred embodiments of the present invention are shown in the drawings. However, the present invention can be implemented in many different forms and is not limited to the embodiments described herein. On the contrary, the purpose of providing these embodiments is to make the disclosure of the present invention more thorough and comprehensive.

[0060] It should be noted that when an element is referred to as being "fixed to" another original, it may be directly on another element or may also have a centered element. When an element is considered to be "connected" to another original, it may be directly connected to another element or may simultaneously have a centered element. On the contrary, when an element is referred to as being "directly on" another original, there is no intermediate element. The terms "vertical", "horizontal", "left", "right" and similar expressions used herein are only for illustrative purposes.

[0061] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art of the present invention. The terms used in this specification are only for the purpose of describing specific embodiments and are not intended to limit the present invention. The term "and / or" used herein includes any and all combinations of one or more related listed items.

[0062] refer to Figure 1 In some embodiments of the present application, the optical system 10 includes, from the object side to the image side, an aperture STO, a first lens L1, a second lens L2, a third lens L3, a fourth lens L4, a fifth lens L5, a sixth lens L6, a seventh lens L7 and an eighth lens L8, and each of the first lens L1 to the eighth lens L8 contains only one lens. Among them, the first lens L1 has positive refractive power, the second lens L2 has negative refractive power, the third lens L3 has positive refractive power or negative refractive power, the fourth lens L4 has positive refractive power or negative refractive power, the fifth lens L5 has positive refractive power or negative refractive power, the sixth lens L6 has negative refractive power, the seventh lens L7 has positive refractive power, and the eighth lens L8 has negative refractive power. Each lens in the optical system 10 is coaxially arranged with the aperture STO, that is, the optical axis of each lens and the center of the aperture STO are located on the same straight line, and the straight line can be called the optical axis of the optical system 10.

[0063] The first lens L1 includes an object-side surface S1 and an image-side surface S2, the second lens L2 includes an object-side surface S3 and an image-side surface S4, the third lens L3 includes an object-side surface S5 and an image-side surface S6, the fourth lens L4 includes an object-side surface S7 and an image-side surface S8, the fifth lens L5 includes an object-side surface S9 and an image-side surface S10, the sixth lens includes an object-side surface S11 and an image-side surface S12, the seventh lens includes an object-side surface S13 and an image-side surface S14, and the eighth lens includes an object-side surface S15 and an image-side surface S16. In addition, the optical system 10 also has a virtual imaging surface S19, and the imaging surface S19 is located on the image side of the eighth lens. Generally, the imaging surface S19 of the optical system 10 coincides with the photosensitive surface of the photosensitive element. For ease of understanding, the imaging surface S19 can be regarded as the photosensitive surface of the photosensitive element.

[0064] In the above embodiment, the object-side surface S1 of the first lens L1 is convex at the optical axis, and the image-side surface S2 is concave at the optical axis; the object-side surface S3 of the second lens L2 is convex at the optical axis, and the image-side surface S4 is concave at the optical axis; the object-side surface S13 of the seventh lens is convex at the optical axis, and the image-side surface S14 is concave at the optical axis; and the image-side surface S16 of the eighth lens is concave at the optical axis.

[0065] In the above embodiment, the object side and image side of the first lens L1 to the eighth lens L8 are all aspherical surfaces, and the object side S15 and image side S16 of the eighth lens L8 both have inflection points. The aspherical surface setting can further help the optical system 10 eliminate aberrations and solve the problem of field of view distortion, and is also conducive to the miniaturization design of the optical system 10, so that the optical system 10 can have excellent optical effects while maintaining a miniaturized design. Of course, in other embodiments, the object side of any one of the first lens L1 to the eighth lens L8 can be a spherical surface or an aspherical surface; the image side of any one of the first lens L1 to the eighth lens L8 can be a spherical surface or an aspherical surface. The coordination of the spherical surface and the aspherical surface can also effectively eliminate the aberration problem, so that the optical system 10 has an excellent imaging effect, and at the same time improve the flexibility of lens design and assembly. In particular, when the eighth lens L8 is an aspherical lens, it will be beneficial to finally correct the aberrations generated by the front lenses, thereby improving the imaging quality. It should be noted that the shape of the spherical or aspherical surface is not limited to the shape of the spherical or aspherical surface shown in the drawings, which are only for example reference and are not drawn strictly to scale.

[0066] The calculation of the aspheric surface can refer to the aspheric surface formula:

[0067]

[0068] Among them, Z is the distance from the corresponding point on the aspherical surface to the plane tangent to the surface vertex, r is the distance from the corresponding point on the aspherical surface to the optical axis, c is the curvature of the aspherical vertex, k is the cone coefficient, and Ai is the coefficient corresponding to the i-th high-order term in the aspherical surface shape formula.

[0069] On the other hand, in some embodiments, when the object side or image side of a lens is an aspheric surface, the surface may be a structure that is convex as a whole or concave as a whole; or the surface may be designed to have a structure with an inflection point, in which case the surface shape of the surface from the center to the edge will change, for example, the surface is convex at the center and concave at the edge. It should be noted that when the embodiments of the present application describe a side surface of a lens as convex at the optical axis (the central area of ​​the side surface), it can be understood that the area of ​​the side surface of the lens near the optical axis is convex, and therefore the side surface can also be considered to be convex at the near axis; when describing a side surface of a lens as concave at the circumference, it can be understood that the area of ​​the side surface near the maximum effective semi-aperture is concave. For example, when the side surface is convex at the optical axis and is also convex at the circumference, the shape of the side surface from the center (optical axis) to the edge direction may be a pure convex surface; or it may first transition from a convex shape at the center to a concave shape, and then become convex when approaching the maximum effective semi-aperture. This is only an example to illustrate the relationship between the optical axis and the circumference. The various shape structures (concave-convex relationship) of the side are not fully reflected, but other situations can be deduced based on the above examples and should also be regarded as the content recorded in this application.

[0070] In the above embodiments, the material of each lens in the optical system 10 is plastic. Of course, in some embodiments, the material of each lens in the optical system 10 is glass. Plastic lenses can reduce the weight of the optical system 10 and reduce production costs, while glass lenses can withstand higher temperatures and have excellent optical effects. In other embodiments, the material of the first lens L1 is glass, and the materials of the second lens L2 to the eighth lens L8 are all plastic. At this time, since the material of the lens located on the object side in the optical system 10 is glass, these glass lenses located on the object side have a good tolerance effect on extreme environments and are not easily affected by the object side environment and aging, etc., so when the optical system 10 is in an extreme environment such as exposure to high temperature, this structure can better balance the optical performance and cost of the system. Of course, the lens material configuration relationship in the optical system 10 is not limited to the above embodiments, and the material of any lens can be plastic or glass.

[0071] In some embodiments, the optical system 10 includes an infrared cut-off filter L9, which is disposed on the image side of the eighth lens L8 and fixedly disposed relative to each lens in the optical system 10. The infrared cut-off filter L9 includes an object side surface S17 and an image side surface S18. The infrared cut-off filter L9 is used to filter out infrared light to prevent infrared light from reaching the imaging surface S19 of the system, thereby preventing infrared light from interfering with normal imaging. The infrared cut-off filter L9 can be assembled together with each lens as a part of the optical system 10. In other embodiments, the infrared cut-off filter L9 does not belong to the components of the optical system 10. In this case, the infrared cut-off filter L9 can be installed between the optical system 10 and the photosensitive element when the optical system 10 and the photosensitive element are assembled into a camera module. In some embodiments, the infrared cut-off filter L9 can also be disposed on the object side of the first lens L1. In addition, in some embodiments, the infrared cut-off filter L9 may not be disposed, but a filter coating may be disposed on any lens from the first lens L1 to the eighth lens L8 to achieve the effect of filtering out infrared light.

[0072] In some other embodiments, the first lens L1 may also include two or more lenses, wherein the object-side surface of the lens closest to the object side is the object-side surface S1 of the first lens L1, and the image-side surface of the lens closest to the image side is the image-side surface S2 of the first lens L1. Accordingly, in some embodiments, any one of the second lens L2, the third lens L3, the fourth lens L4, the fifth lens L5, the sixth lens L6, the seventh lens L7, and the eighth lens L8 is not limited to the case of including only one lens.

[0073] In some embodiments, the optical system 10 also satisfies the following relationships:

[0074] 0.2<DL / Imgh<0.5; wherein DL is the aperture size of the optical system 10, and Imgh is the diagonal length of the effective imaging area of ​​the optical system 10 on the imaging surface S19. DL / Imgh in some embodiments is 0.30, 0.31, 0.33, 0.35, 0.36 or 0.37. The aperture size of the system's aperture STO determines the light throughput of the entire system, and the size of the imaging surface S19 determines the pixel size and picture clarity of the entire system. A reasonable combination of the two can ensure that the system has a reasonable light throughput to ensure the clarity of the shooting. When the optical system 10 satisfies the above-mentioned lens refractive power, surface shape and conditional relationship, the light throughput of the optical system 10 and the size of the imaging surface S19 can be reasonably configured, thereby effectively improving the shooting quality of the system in a dark light environment. When DL / Imgh>0.5, the system will be overexposed and the brightness will be too high, which will eventually affect the picture quality; when DL / Imgh<0.2, the system will have insufficient light transmittance and the relative brightness of the light will be insufficient, which will cause a decrease in picture clarity.

[0075] 0<sin(FOV) / TTL<0.2; wherein FOV is the maximum field of view of the optical system 10, TTL is the distance from the object side S1 of the first lens L1 to the imaging surface S19 of the optical system 10 on the optical axis, and the unit of TTL is mm. In some embodiments, sin(FOV) / TTL is 0.145, 0.15, 0.155 or 0.16, and the numerical unit is (1 / mm). When the above relationship is met, the optical system 10 can simultaneously meet the effects of miniaturization and shooting of a large range of scenes, while also meeting the requirements of high-definition shooting. When sin(FOV) / TTL>0.2, the structure of the system is too compact and it is difficult to correct aberrations, resulting in a decrease in imaging performance; when SIN(FOV) / TTL<0, the structure of the system will be too long, making it difficult to meet the requirements of miniaturization design.

[0076] Fno / TTL<0.5; wherein Fno is the aperture number of the optical system 10, TTL is the distance from the object side surface S1 of the first lens L1 to the imaging surface S19 of the optical system 10 on the optical axis, and the unit of TTL is mm. In some embodiments, Fno / TTL is 0.23, 0.24, 0.25, 0.26, 0.27, 0.28 or 0.29, and the numerical unit is (1 / mm). When the above relationship is met, the optical system 10 can take into account the design requirements of large aperture and miniaturization at the same time, provide sufficient light throughput for shooting, and meet the needs of high-quality and high-definition shooting. When Fno / TTL>0.5, the system will cause insufficient light throughput while taking into account miniaturization, resulting in a decrease in the clarity of the captured image.

[0077] 0.1≤BFL / TTL<0.4; wherein BFL is the shortest distance from the image side surface S16 of the eighth lens L8 to the imaging surface S19 of the optical system 10 in the direction parallel to the optical axis, and TTL is the distance from the object side surface S1 of the first lens L1 to the imaging surface S19 of the optical system 10 on the optical axis. In some embodiments, BFL / TTL is 0.10, 0.11, 0.12, 0.13 or 0.14. When the above relationship is met, it can be ensured that the system has a sufficient focusing range to improve the assembly yield of the module, and at the same time, it can be ensured that the system has a larger focal depth to obtain more depth information on the object side.

[0078] -4<f6 / f7<0; wherein, f6 is the effective focal length of the sixth lens L6, and f7 is the effective focal length of the seventh lens L7. In some embodiments, f6 / f7 is -3.25, -3.20, -3.10, -3.00, -2.80, -2.60, -2.50, -2.40 or -2.30. The sixth lens L6 provides negative refractive power to diverge the light to meet the image height requirement, while the seventh lens L7 provides positive refractive power to facilitate the convergence of light. When the above relationship is met, the refractive power of the two will be reasonably distributed, which can not only effectively compress the system volume and achieve the miniaturization design requirements, but also can well correct the aberrations and field curvature of the entire optical system 10.

[0079] 0.2<DL / TTL<1; wherein DL is the aperture size of the optical system 10, and TTL is the distance from the object side S1 of the first lens L1 to the imaging surface S19 of the optical system 10 on the optical axis. DL / TTL in some embodiments is 0.42, 0.43, 0.44, 0.45, 0.46, 0.48 or 0.50. When the above relationship is met, the miniaturization design of the system can be guaranteed, and the amount of light required for the system shooting can be provided to achieve high-quality and high-definition shooting effects. When DL / TTL>1, the system will cause the aperture of the aperture STO to be too large when meeting the miniaturization design, causing the edge light to enter the system, thereby reducing the imaging quality; when DL / TTL<0.2, the system will cause the aperture of the aperture STO to be too small when meeting the miniaturization design, thereby failing to meet the light throughput requirements of the system and failing to achieve high-definition shooting requirements in dark light environments.

[0080] TTL / Imgh<1; wherein TTL is the distance on the optical axis from the object side surface S1 of the first lens L1 to the imaging surface S19 of the optical system 10, and Imgh is the diagonal length of the effective imaging area of ​​the optical system 10 on the imaging surface S19. In some embodiments, TTL / Imgh is 0.70, 0.71, 0.72, 0.73 or 0.74. When the above relationship is satisfied, the optical system 10 can take into account both miniaturization design and high-definition shooting. When TTL / Imgh>1, the system cannot guarantee high-definition imaging effect while achieving miniaturization.

[0081] 1.0<TTL / f<2.0; wherein TTL is the distance from the object side surface S1 of the first lens L1 to the imaging surface S19 of the optical system 10 on the optical axis, and f is the effective focal length of the optical system 10. In some embodiments, TTL / f is 1.21, 1.22, 1.24, 1.25, 1.27, 1.29 or 1.30. When the above relationship is satisfied, the effective focal length and the total optical length of the optical system 10 will be reasonably configured, which can not only realize the miniaturized design, but also ensure that the light is better converged on the imaging surface S19 of the system, thereby helping to improve the imaging quality and ensure the authenticity of the image. When TTL / f≤1.0, the optical length of the system is too short, which will increase the sensitivity of the system and is not conducive to the convergence of light on the imaging surface S19; when TTL / f≥2, the optical length of the system is too long, which will cause the main light angle when the light enters the imaging surface S19 to be too large, so that the marginal light cannot be imaged on the imaging surface S19, thereby causing incomplete imaging information.

[0082] 0<R11 / R12<3.5; wherein R11 is the radius of curvature of the object-side surface S11 of the sixth lens L6 at the optical axis, and R12 is the radius of curvature of the image-side surface S12 of the sixth lens L6 at the optical axis. In some embodiments, R11 / R12 is 0.60, 0.70, 0.80, 1.00, 1.20, 1.50, 1.80, 2.00, 2.10, 2.30, 2.50, 2.60 or 2.70. When the above relationship is satisfied, the radius of curvature of the object-side surface S11 and the image-side surface S12 of the sixth lens L6 can be appropriately configured, which is beneficial to reduce the sensitivity of the system and improve the molding yield.

[0083] Next, the optical system 10 of the present application is described with more specific and detailed embodiments:

[0084] First embodiment

[0085] refer to Figure 1 and Figure 2 In the first embodiment, the optical system 10 includes, from the object side to the image side, an aperture stop STO, a first lens L1 with positive refractive power, a second lens L2 with negative refractive power, a third lens L3 with negative refractive power, a fourth lens L4 with positive refractive power, a fifth lens L5 with negative refractive power, a sixth lens L6 with negative refractive power, a seventh lens L7 with positive refractive power, and an eighth lens L8 with negative refractive power. Figure 2 The diagram includes a longitudinal spherical aberration diagram (mm), an astigmatism diagram (mm) and a distortion diagram (%) of the optical system 10 in the first embodiment. The ordinates of the astigmatism diagram and the distortion diagram can be understood as half of the diagonal length of the effective imaging area on the imaging surface S19, in units of mm. In addition, the astigmatism diagram and the distortion diagram are curve diagrams at a wavelength of 555 nm.

[0086] The object-side surface S1 of the first lens L1 is convex at the optical axis, and the image-side surface S2 is concave at the optical axis; the object-side surface S1 is convex at the circumference, and the image-side surface S2 is concave at the circumference.

[0087] The object-side surface S3 of the second lens L2 is convex at the optical axis, and the image-side surface S4 is concave at the optical axis; the object-side surface S3 is convex at the circumference, and the image-side surface S4 is concave at the circumference.

[0088] The object-side surface S5 of the third lens L3 is convex at the optical axis, and the image-side surface S6 is concave at the optical axis; the object-side surface S5 is concave at the circumference, and the image-side surface S6 is convex at the circumference.

[0089] The object-side surface S7 of the fourth lens L4 is convex at the optical axis, and the image-side surface S8 is convex at the optical axis; the object-side surface S7 is convex at the circumference, and the image-side surface S8 is concave at the circumference.

[0090] The object-side surface S9 of the fifth lens L5 is concave at the optical axis, and the image-side surface S10 is convex at the optical axis; the object-side surface S9 is concave at the circumference, and the image-side surface S10 is convex at the circumference.

[0091] The object-side surface S11 of the sixth lens L6 is convex at the optical axis, and the image-side surface S12 is concave at the optical axis; the object-side surface S11 is concave at the circumference, and the image-side surface S12 is convex at the circumference.

[0092] The object-side surface S13 of the seventh lens L7 is convex at the optical axis, and the image-side surface S14 is concave at the optical axis; the object-side surface S13 is concave at the circumference, and the image-side surface S14 is convex at the circumference.

[0093] The object-side surface S15 of the eighth lens L8 is concave at the optical axis, and the image-side surface S16 is concave at the optical axis; the object-side surface S15 is concave at the circumference, and the image-side surface S16 is concave at the circumference.

[0094] The object side and image side of each lens from the first lens L1 to the eighth lens L8 are aspherical, and the object side S15 and image side S16 of the eighth lens L8 both have inflection points. By matching the aspherical surface of each lens in the optical system 10, the problem of visual field distortion of the optical system 10 can be effectively solved, and the lens can also achieve excellent optical effects in a smaller and thinner case, thereby making the optical system 10 have a smaller volume, which is conducive to the miniaturization design of the optical system 10. And the material of each lens in the optical system 10 is plastic. The use of plastic lenses can reduce the manufacturing cost of the optical system 10.

[0095] In the first embodiment, the optical system 10 satisfies the following relationships:

[0096] DL / Imgh=0.37; wherein DL is the aperture size of the optical system 10, and Imgh is the diagonal length of the effective imaging area of ​​the optical system 10 on the imaging surface S19. The aperture size of the system determines the light flux of the entire system, and the size of the imaging surface S19 determines the pixel size and image clarity of the entire system. The reasonable combination of the two can ensure that the system has a reasonable light flux to ensure the clarity of the shooting. When the optical system 10 satisfies the above-mentioned relationship between the refractive power, surface shape and conditional formula of the lens, the light flux of the optical system 10 and the size of the imaging surface S19 can be reasonably configured, thereby effectively improving the shooting quality of the system in a dark light environment.

[0097] sin(FOV) / TTL=0.14(1 / mm); wherein FOV is the maximum field of view of the optical system 10, TTL is the distance from the object side surface S1 of the first lens L1 to the imaging surface S19 of the optical system 10 on the optical axis, and the unit of TTL is mm. When the above relationship is satisfied, the optical system 10 can simultaneously meet the requirements of miniaturization and the effects of shooting a wide range of scenes, and can also meet the requirements of high-definition shooting.

[0098] Fno / TTL=0.24(1 / mm); wherein Fno is the aperture number of the optical system 10, TTL is the distance from the object side surface S1 of the first lens L1 to the imaging surface S19 of the optical system 10 on the optical axis, and the unit of TTL is mm. When the above relationship is satisfied, the optical system 10 can simultaneously take into account the design requirements of large aperture and miniaturization, provide sufficient light transmission for shooting, and meet the needs of high-quality and high-definition shooting.

[0099] BFL / TTL=0.14; wherein BFL is the shortest distance between the image side surface S16 of the eighth lens L8 and the imaging surface S19 of the optical system 10 in the direction parallel to the optical axis, and TTL is the distance between the object side surface S1 of the first lens L1 and the imaging surface S19 of the optical system 10 on the optical axis. When the above relationship is satisfied, it can ensure that the system has a sufficient focusing range to improve the assembly yield of the module, and at the same time ensure that the system has a larger focal depth to obtain more depth information on the object side.

[0100] f6 / f7=-3.08; where f6 is the effective focal length of the sixth lens L6, and f7 is the effective focal length of the seventh lens L7. The sixth lens L6 provides negative refractive power to diverge the light to meet the image height requirement, while the seventh lens L7 provides positive refractive power to facilitate light convergence. When the above relationship is met, the refractive power of the two will be reasonably distributed, which can not only effectively compress the system volume and achieve the miniaturization design requirements, but also can well correct the aberration and field curvature of the entire optical system 10.

[0101] DL / TTL=0.51; wherein DL is the aperture size of the optical system 10, and TTL is the distance on the optical axis from the object side surface S1 of the first lens L1 to the imaging surface S19 of the optical system 10. When the above relationship is satisfied, the miniaturization design of the system can be ensured, and the light flux required for the system shooting can be provided to achieve high-quality and high-definition shooting effects.

[0102] TTL / Imgh=0.73; wherein TTL is the distance on the optical axis from the object side surface S1 of the first lens L1 to the imaging surface S19 of the optical system 10, and Imgh is the diagonal length of the effective imaging area of ​​the optical system 10 on the imaging surface S19. When the above relationship is satisfied, the optical system 10 can take into account both miniaturization design and high-definition photography.

[0103] TTL / f=1.21; wherein TTL is the distance on the optical axis from the object side surface S1 of the first lens L1 to the imaging surface S19 of the optical system 10, and f is the effective focal length of the optical system 10. When the above relationship is satisfied, the effective focal length and the total optical length of the optical system 10 will be reasonably configured, which can not only realize a miniaturized design, but also ensure that the light is better converged on the imaging surface S19 of the system, thereby facilitating the improvement of imaging quality and ensuring the authenticity of the image.

[0104] R11 / R12=2.03; wherein R11 is the radius of curvature of the object side surface S11 of the sixth lens L6 at the optical axis, and R12 is the radius of curvature of the image side surface S12 of the sixth lens L6 at the optical axis. When the above relationship is satisfied, the radius of curvature of the object side surface S11 and the image side surface S12 of the sixth lens L6 can be appropriately configured, which is beneficial to reducing the sensitivity of the system and improving the molding yield.

[0105] In addition, the parameters of each lens of the optical system 10 are given in Table 1 and Table 2. Table 2 shows the aspheric coefficients of each lens in Table 1, where K is the cone coefficient and Ai is the coefficient corresponding to the i-th high-order term in the aspheric surface formula. The components from the object plane to the image plane (imaging surface S19, which can also be understood as the photosensitive surface of the photosensitive element during later assembly) are arranged in the order of the components from top to bottom in Table 1, wherein the subject located on the object plane can form a clear image on the imaging surface S19 of the optical system 10. Surface numbers 1 and 2 respectively represent the object side surface S1 and the image side surface S2 of the first lens L1, that is, in the same lens, the surface with a smaller surface number is the object side surface, and the surface with a larger surface number is the image side surface. The Y radius in Table 1 is the radius of curvature of the object side surface or the image side surface of the corresponding surface number on the optical axis. The first value of the lens in the "thickness" parameter column is the thickness of the lens on the optical axis, and the second value is the distance from the image side surface of the lens to the object side surface of the next optical element on the optical axis. The value of aperture ST0 in the "Thickness" parameter column is the distance from aperture ST0 to the vertex of the object side of the next lens (the vertex refers to the intersection of the lens and the optical axis) on the optical axis. We assume that the direction from the object side of the first lens L1 to the image side of the last lens is the positive direction of the optical axis. When the value is negative, it indicates that the aperture ST0 is set to the right side of the vertex of the object side of the lens. When the "Thickness" parameter of the aperture ST0 is a positive value, the aperture ST0 is on the left side of the vertex of the object side of the lens. The optical axes of the lenses in the embodiments of the present application are on the same straight line, and the straight line serves as the optical axis of the optical system 10. It should be noted that in the following embodiments, the infrared cutoff filter L9 may be used as a component in the optical system 10, or may not be used as a component in the optical system 10.

[0106] In the first embodiment, the effective focal length f of the optical system 10 is 5.55 mm, the aperture number FNO is 1.63, the maximum field angle (ie, the viewing angle in the diagonal direction) FOV is 77.61°, and the total optical length TTL is 6.74 mm.

[0107] In addition, in the following embodiments (the first embodiment to the seventh embodiment), the refractive index, Abbe number and focal length of each lens are all values ​​at a wavelength of 555nm. In addition, the relationship calculation and lens structure of each embodiment shall be based on the lens parameters (such as Table 1, Table 2, Table 3, Table 4, etc.).

[0108] Table 1

[0109]

[0110]

[0111] Table 2

[0112]

[0113]

[0114] Second embodiment

[0115] refer to Figure 3 and Figure 4 In the second embodiment, the optical system 10 includes, from the object side to the image side, an aperture stop STO, a first lens L1 with positive refractive power, a second lens L2 with negative refractive power, a third lens L3 with negative refractive power, a fourth lens L4 with positive refractive power, a fifth lens L5 with positive refractive power, a sixth lens L6 with negative refractive power, a seventh lens L7 with positive refractive power, and an eighth lens L8 with negative refractive power. Figure 4 It includes a longitudinal spherical aberration diagram (mm), an astigmatism diagram (mm) and a distortion diagram (%) of the optical system 10 in the second embodiment, wherein the astigmatism diagram and the distortion diagram are curve diagrams at a wavelength of 555 nm.

[0116] The object-side surface S1 of the first lens L1 is convex at the optical axis, and the image-side surface S2 is concave at the optical axis; the object-side surface S1 is convex at the circumference, and the image-side surface S2 is concave at the circumference.

[0117] The object-side surface S3 of the second lens L2 is convex at the optical axis, and the image-side surface S4 is concave at the optical axis; the object-side surface S3 is convex at the circumference, and the image-side surface S4 is concave at the circumference.

[0118] The object-side surface S5 of the third lens L3 is concave at the optical axis, and the image-side surface S6 is convex at the optical axis; the object-side surface S5 is concave at the circumference, and the image-side surface S6 is convex at the circumference.

[0119] The object-side surface S7 of the fourth lens L4 is convex at the optical axis, and the image-side surface S8 is concave at the optical axis; the object-side surface S7 is convex at the circumference, and the image-side surface S8 is concave at the circumference.

[0120] The object-side surface S9 of the fifth lens L5 is convex at the optical axis, and the image-side surface S10 is convex at the optical axis; the object-side surface S9 is convex at the circumference, and the image-side surface S10 is concave at the circumference.

[0121] The object-side surface S11 of the sixth lens L6 is concave at the optical axis, and the image-side surface S12 is convex at the optical axis; the object-side surface S11 is convex at the circumference, and the image-side surface S12 is convex at the circumference.

[0122] The object-side surface S13 of the seventh lens L7 is convex at the optical axis, and the image-side surface S14 is concave at the optical axis; the object-side surface S13 is concave at the circumference, and the image-side surface S14 is convex at the circumference.

[0123] The object-side surface S15 of the eighth lens L8 is convex at the optical axis, and the image-side surface S16 is concave at the optical axis; the object-side surface S15 is concave at the circumference, and the image-side surface S16 is concave at the circumference.

[0124] In addition, the lens parameters of the optical system 10 in the second embodiment are given in Table 3 and Table 4, wherein the definitions of the structures and parameters can be obtained from the first embodiment and are not described in detail here.

[0125] Table 3

[0126]

[0127]

[0128] Table 4

[0129]

[0130]

[0131] The optical system 10 in this embodiment satisfies the following relationship:

[0132]

[0133] Third embodiment

[0134] refer to Figure 5 and Figure 6 In the third embodiment, the optical system 10 includes, from the object side to the image side, an aperture stop STO, a first lens L1 with positive refractive power, a second lens L2 with negative refractive power, a third lens L3 with negative refractive power, a fourth lens L4 with positive refractive power, a fifth lens L5 with positive refractive power, a sixth lens L6 with negative refractive power, a seventh lens L7 with positive refractive power, and an eighth lens L8 with negative refractive power. Figure 6 It includes a longitudinal spherical aberration diagram (mm), an astigmatism diagram (mm) and a distortion diagram (%) of the optical system 10 in the third embodiment, wherein the astigmatism diagram and the distortion diagram are curve diagrams at a wavelength of 555 nm.

[0135] The object-side surface S1 of the first lens L1 is convex at the optical axis, and the image-side surface S2 is concave at the optical axis; the object-side surface S1 is convex at the circumference, and the image-side surface S2 is concave at the circumference.

[0136] The object-side surface S3 of the second lens L2 is convex at the optical axis, and the image-side surface S4 is concave at the optical axis; the object-side surface S3 is convex at the circumference, and the image-side surface S4 is concave at the circumference.

[0137] The object-side surface S5 of the third lens L3 is convex at the optical axis, and the image-side surface S6 is concave at the optical axis; the object-side surface S5 is concave at the circumference, and the image-side surface S6 is convex at the circumference.

[0138] The object-side surface S7 of the fourth lens L4 is convex at the optical axis, and the image-side surface S8 is convex at the optical axis; the object-side surface S7 is convex at the circumference, and the image-side surface S8 is concave at the circumference.

[0139] The object-side surface S9 of the fifth lens L5 is concave at the optical axis, and the image-side surface S10 is convex at the optical axis; the object-side surface S9 is concave at the circumference, and the image-side surface S10 is convex at the circumference.

[0140] The object-side surface S11 of the sixth lens L6 is convex at the optical axis, and the image-side surface S12 is concave at the optical axis; the object-side surface S11 is concave at the circumference, and the image-side surface S12 is convex at the circumference.

[0141] The object-side surface S13 of the seventh lens L7 is convex at the optical axis, and the image-side surface S14 is concave at the optical axis; the object-side surface S13 is concave at the circumference, and the image-side surface S14 is convex at the circumference.

[0142] The object-side surface S15 of the eighth lens L8 is concave at the optical axis, and the image-side surface S16 is concave at the optical axis; the object-side surface S15 is concave at the circumference, and the image-side surface S16 is concave at the circumference.

[0143] In addition, the lens parameters of the optical system 10 in the third embodiment are given in Table 5 and Table 6, wherein the definitions of the structures and parameters can be obtained from the first embodiment and are not elaborated here.

[0144] Table 5

[0145]

[0146] Table 6

[0147]

[0148]

[0149] The optical system 10 in this embodiment satisfies the following relationship:

[0150]

[0151] Fourth embodiment

[0152] refer to Figure 7 and Figure 8In the fourth embodiment, the optical system 10 includes, from the object side to the image side, an aperture stop STO, a first lens L1 with positive refractive power, a second lens L2 with negative refractive power, a third lens L3 with negative refractive power, a fourth lens L4 with positive refractive power, a fifth lens L5 with positive refractive power, a sixth lens L6 with negative refractive power, a seventh lens L7 with positive refractive power, and an eighth lens L8 with negative refractive power. Figure 8 It includes a longitudinal spherical aberration diagram (mm), an astigmatism diagram (mm) and a distortion diagram (%) of the optical system 10 in the fourth embodiment, wherein the astigmatism diagram and the distortion diagram are curve diagrams at a wavelength of 555 nm.

[0153] The object-side surface S1 of the first lens L1 is convex at the optical axis, and the image-side surface S2 is concave at the optical axis; the object-side surface S1 is convex at the circumference, and the image-side surface S2 is concave at the circumference.

[0154] The object-side surface S3 of the second lens L2 is convex at the optical axis, and the image-side surface S4 is concave at the optical axis; the object-side surface S3 is convex at the circumference, and the image-side surface S4 is concave at the circumference.

[0155] The object-side surface S5 of the third lens L3 is convex at the optical axis, and the image-side surface S6 is concave at the optical axis; the object-side surface S5 is concave at the circumference, and the image-side surface S6 is convex at the circumference.

[0156] The object-side surface S7 of the fourth lens L4 is convex at the optical axis, and the image-side surface S8 is convex at the optical axis; the object-side surface S7 is convex at the circumference, and the image-side surface S8 is concave at the circumference.

[0157] The object-side surface S9 of the fifth lens L5 is concave at the optical axis, and the image-side surface S10 is convex at the optical axis; the object-side surface S9 is concave at the circumference, and the image-side surface S10 is convex at the circumference.

[0158] The object-side surface S11 of the sixth lens L6 is convex at the optical axis, and the image-side surface S12 is concave at the optical axis; the object-side surface S11 is concave at the circumference, and the image-side surface S12 is convex at the circumference.

[0159] The object-side surface S13 of the seventh lens L7 is convex at the optical axis, and the image-side surface S14 is concave at the optical axis; the object-side surface S13 is concave at the circumference, and the image-side surface S14 is convex at the circumference.

[0160] The object-side surface S15 of the eighth lens L8 is concave at the optical axis, and the image-side surface S16 is concave at the optical axis; the object-side surface S15 is convex at the circumference, and the image-side surface S16 is concave at the circumference.

[0161] In addition, the lens parameters of the optical system 10 in the fourth embodiment are given in Table 7 and Table 8, wherein the definitions of the structures and parameters can be obtained from the first embodiment and will not be repeated here.

[0162] Table 7

[0163]

[0164] Table 8

[0165]

[0166] The optical system 10 in this embodiment satisfies the following relationship:

[0167]

[0168]

[0169] Fifth embodiment

[0170] refer to Fig. 9 and Fig.10 In the fifth embodiment, the optical system 10 includes, from the object side to the image side, an aperture stop STO, a first lens L1 with positive refractive power, a second lens L2 with negative refractive power, a third lens L3 with positive refractive power, a fourth lens L4 with negative refractive power, a fifth lens L5 with positive refractive power, a sixth lens L6 with negative refractive power, a seventh lens L7 with positive refractive power, and an eighth lens L8 with negative refractive power. Fig.10 It includes a longitudinal spherical aberration diagram (mm), an astigmatism diagram (mm) and a distortion diagram (%) of the optical system 10 in the fifth embodiment, wherein the astigmatism diagram and the distortion diagram are curve diagrams at a wavelength of 555 nm.

[0171] The object-side surface S1 of the first lens L1 is convex at the optical axis, and the image-side surface S2 is concave at the optical axis; the object-side surface S1 is convex at the circumference, and the image-side surface S2 is concave at the circumference.

[0172] The object-side surface S3 of the second lens L2 is convex at the optical axis, and the image-side surface S4 is concave at the optical axis; the object-side surface S3 is convex at the circumference, and the image-side surface S4 is concave at the circumference.

[0173] The object-side surface S5 of the third lens L3 is concave at the optical axis, and the image-side surface S6 is convex at the optical axis; the object-side surface S5 is concave at the circumference, and the image-side surface S6 is convex at the circumference.

[0174] The object-side surface S7 of the fourth lens L4 is concave at the optical axis, and the image-side surface S8 is concave at the optical axis; the object-side surface S7 is concave at the circumference, and the image-side surface S8 is convex at the circumference.

[0175] The object-side surface S9 of the fifth lens L5 is convex at the optical axis, and the image-side surface S10 is concave at the optical axis; the object-side surface S9 is concave at the circumference, and the image-side surface S10 is concave at the circumference.

[0176] The object-side surface S11 of the sixth lens L6 is concave at the optical axis, and the image-side surface S12 is convex at the optical axis; the object-side surface S11 is convex at the circumference, and the image-side surface S12 is concave at the circumference.

[0177] The object-side surface S13 of the seventh lens L7 is convex at the optical axis, and the image-side surface S14 is concave at the optical axis; the object-side surface S13 is concave at the circumference, and the image-side surface S14 is convex at the circumference.

[0178] The object-side surface S15 of the eighth lens L8 is convex at the optical axis, and the image-side surface S16 is concave at the optical axis; the object-side surface S15 is concave at the circumference, and the image-side surface S16 is concave at the circumference.

[0179] In addition, the lens parameters of the optical system 10 in the fifth embodiment are given in Tables 9 and 10, wherein the definitions of the structures and parameters can be obtained from the first embodiment and will not be elaborated here.

[0180] Table 9

[0181]

[0182]

[0183] Table 10

[0184]

[0185]

[0186] The optical system 10 in this embodiment satisfies the following relationship:

[0187]

[0188] Sixth embodiment

[0189] refer to Fig.11 and Fig.12 In the sixth embodiment, the optical system 10 includes, from the object side to the image side, an aperture stop STO, a first lens L1 with positive refractive power, a second lens L2 with negative refractive power, a third lens L3 with negative refractive power, a fourth lens L4 with positive refractive power, a fifth lens L5 with negative refractive power, a sixth lens L6 with negative refractive power, a seventh lens L7 with positive refractive power, and an eighth lens L8 with negative refractive power. Fig.12 It includes the longitudinal spherical aberration diagram (mm), astigmatism diagram (mm) and distortion diagram (%) of the optical system 10 in the sixth embodiment, wherein the astigmatism diagram and the distortion diagram are curve diagrams at a wavelength of 555nm.

[0190] The object-side surface S1 of the first lens L1 is convex at the optical axis, and the image-side surface S2 is concave at the optical axis; the object-side surface S1 is convex at the circumference, and the image-side surface S2 is concave at the circumference.

[0191] The object-side surface S3 of the second lens L2 is convex at the optical axis, and the image-side surface S4 is concave at the optical axis; the object-side surface S3 is convex at the circumference, and the image-side surface S4 is concave at the circumference.

[0192] The object-side surface S5 of the third lens L3 is convex at the optical axis, and the image-side surface S6 is concave at the optical axis; the object-side surface S5 is concave at the circumference, and the image-side surface S6 is convex at the circumference.

[0193] The object-side surface S7 of the fourth lens L4 is convex at the optical axis, and the image-side surface S8 is convex at the optical axis; the object-side surface S7 is concave at the circumference, and the image-side surface S8 is convex at the circumference.

[0194] The object-side surface S9 of the fifth lens L5 is concave at the optical axis, and the image-side surface S10 is convex at the optical axis; the object-side surface S9 is concave at the circumference, and the image-side surface S10 is convex at the circumference.

[0195] The object-side surface S11 of the sixth lens L6 is convex at the optical axis, and the image-side surface S12 is concave at the optical axis; the object-side surface S11 is concave at the circumference, and the image-side surface S12 is convex at the circumference.

[0196] The object-side surface S13 of the seventh lens L7 is convex at the optical axis, and the image-side surface S14 is concave at the optical axis; the object-side surface S13 is concave at the circumference, and the image-side surface S14 is convex at the circumference.

[0197] The object-side surface S15 of the eighth lens L8 is concave at the optical axis, and the image-side surface S16 is concave at the optical axis; the object-side surface S15 is concave at the circumference, and the image-side surface S16 is convex at the circumference.

[0198] In addition, the lens parameters of the optical system 10 in the sixth embodiment are given in Table 11 and Table 12, wherein the definitions of the structures and parameters can be obtained from the first embodiment and will not be repeated here.

[0199] Table 11

[0200]

[0201]

[0202] Table 12

[0203]

[0204]

[0205] The optical system 10 in this embodiment satisfies the following relationship:

[0206]

[0207] Seventh embodiment

[0208] refer to Fig.13 and Fig.14 In the seventh embodiment, the optical system 10 includes, from the object side to the image side, an aperture stop STO, a first lens L1 with positive refractive power, a second lens L2 with negative refractive power, a third lens L3 with negative refractive power, a fourth lens L4 with positive refractive power, a fifth lens L5 with positive refractive power, a sixth lens L6 with negative refractive power, a seventh lens L7 with positive refractive power, and an eighth lens L8 with negative refractive power. Fig.14 It includes the longitudinal spherical aberration diagram (mm), astigmatism diagram (mm) and distortion diagram (%) of the optical system 10 in the seventh embodiment, wherein the astigmatism diagram and the distortion diagram are curve diagrams at a wavelength of 555nm.

[0209] The object-side surface S1 of the first lens L1 is convex at the optical axis, and the image-side surface S2 is concave at the optical axis; the object-side surface S1 is convex at the circumference, and the image-side surface S2 is concave at the circumference.

[0210] The object-side surface S3 of the second lens L2 is convex at the optical axis, and the image-side surface S4 is concave at the optical axis; the object-side surface S3 is convex at the circumference, and the image-side surface S4 is concave at the circumference.

[0211] The object-side surface S5 of the third lens L3 is convex at the optical axis, and the image-side surface S6 is concave at the optical axis; the object-side surface S5 is concave at the circumference, and the image-side surface S6 is convex at the circumference.

[0212] The object-side surface S7 of the fourth lens L4 is convex at the optical axis, and the image-side surface S8 is convex at the optical axis; the object-side surface S7 is concave at the circumference, and the image-side surface S8 is convex at the circumference.

[0213] The object-side surface S9 of the fifth lens L5 is concave at the optical axis, and the image-side surface S10 is convex at the optical axis; the object-side surface S9 is concave at the circumference, and the image-side surface S10 is convex at the circumference.

[0214] The object-side surface S11 of the sixth lens L6 is convex at the optical axis, and the image-side surface S12 is concave at the optical axis; the object-side surface S11 is concave at the circumference, and the image-side surface S12 is convex at the circumference.

[0215] The object-side surface S13 of the seventh lens L7 is convex at the optical axis, and the image-side surface S14 is concave at the optical axis; the object-side surface S13 is concave at the circumference, and the image-side surface S14 is convex at the circumference.

[0216] The object-side surface S15 of the eighth lens L8 is concave at the optical axis, and the image-side surface S16 is concave at the optical axis; the object-side surface S15 is concave at the circumference, and the image-side surface S16 is convex at the circumference.

[0217] In addition, the lens parameters of the optical system 10 in the seventh embodiment are given in Table 13 and Table 14, wherein the definitions of the structures and parameters can be obtained from the first embodiment and will not be repeated here.

[0218] Table 13

[0219]

[0220] Table 14

[0221]

[0222]

[0223] The optical system 10 in this embodiment satisfies the following relationship:

[0224]

[0225] refer to Fig.15 In one embodiment provided in the present application, the optical system 10 is assembled with a photosensitive element 210 to form a camera module 20, and the photosensitive element 210 is arranged on the image side of the eighth lens L8, that is, on the image side of the optical system 10. Generally, the photosensitive surface of the photosensitive element 210 overlaps with the imaging surface S19 of the optical system 10. An infrared cutoff filter L9 is also arranged between the eighth lens L8 and the photosensitive element 210 in this embodiment. The photosensitive element 210 can be a CCD (Charge Coupled Device) or a CMOS (Complementary Metal Oxide Semiconductor). By adopting the above-mentioned optical system 10, the light throughput of the system and the photosensitive surface size of the photosensitive element 210 can be reasonably configured, thereby effectively improving the shooting quality of the module in a dark light environment.

[0226] In some embodiments, the distance between the photosensitive element 210 and each lens in the optical system 10 is relatively fixed. In this case, the camera module 20 is a fixed focus module. In other embodiments, a driving mechanism such as a voice coil motor can be provided to enable the photosensitive element 210 to move relative to each lens in the optical system 10, thereby achieving a focusing effect. Specifically, a coil electrically connected to a driving chip is provided on the lens barrel on which the above-mentioned lenses are assembled. At the same time, the camera module 20 is also provided with a magnet. The magnetic force between the coil and the magnet after power is applied is used to drive the lens barrel to move relative to the photosensitive element 210, thereby achieving a focusing effect. In other embodiments, a similar driving mechanism can also be provided to drive some lenses in the optical system 10 to move, thereby achieving an optical zoom effect.

[0227] refer to Fig.16 Some embodiments of the present application also provide an electronic device 30, and the camera module 20 is applied to the electronic device 30 so that the electronic device 30 has a camera function. Specifically, the electronic device 30 includes a fixing member 310, and the camera module 20 is installed on the fixing member 310, and the fixing member 310 can be a circuit board, a middle frame and other components. The electronic device 30 can be but not limited to a smart phone, a smart watch, an e-book reader, a vehicle-mounted camera device, a monitoring device, a medical device (such as an endoscope), a tablet computer, a biometric device (such as a fingerprint recognition device or a pupil recognition device, etc.), a PDA (Personal Digital Assistant), a drone, etc. Specifically, in some embodiments, the electronic device 30 is a smart phone, and the smart phone includes a middle frame and a circuit board, and the circuit board is arranged in the middle frame, and the camera module 20 is installed in the middle frame of the smart phone, and the photosensitive element 210 therein is electrically connected to the circuit board. The camera module 20 can be used as a front camera module or a rear camera module of a smart phone. By adopting the camera module 20 provided in the embodiment of the present application, the electronic device 30 can also have excellent shooting quality when shooting dark scenes such as night scenes and starry sky.

[0228] The technical features of the above-described embodiments may be arbitrarily combined. To make the description concise, not all possible combinations of the technical features in the above-described embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0229] The above-mentioned embodiments only express several implementation methods of the present invention, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the invention patent. It should be pointed out that, for ordinary technicians in this field, several variations and improvements can be made without departing from the concept of the present invention, and these all belong to the protection scope of the present invention. Therefore, the protection scope of the patent of the present invention shall be subject to the attached claims.

Claims

1. An optical system, characterized in that: From the object side to the image side, it includes: A first lens having positive refractive power, wherein the object side surface of the first lens is convex at the optical axis, and the image side surface of the first lens is concave at the optical axis; a second lens having negative refractive power, wherein the object-side surface of the second lens is convex at the optical axis, and the image-side surface of the second lens is concave at the optical axis; a third lens having refractive power; a fourth lens having a refractive power; a fifth lens having refractive power; a sixth lens element having negative refractive power; a seventh lens having positive refractive power, wherein the object-side surface of the seventh lens is convex at the optical axis, and the image-side surface of the seventh lens is concave at the optical axis; an eighth lens having negative refractive power, wherein the image side surface of the eighth lens is concave at the optical axis; The optical system satisfies the following relationship: 0.29≤DL / Imgh≤0.33, -3.19≤f6 / f7≤-2.77, 0.42≤DL / TTL≤0.47, TTL / Imgh≤0.70, 1.21≤TTL / f≤1.28, 1.83≤R11 / R12≤2.49; Wherein, DL is the aperture size of the optical system, Imgh is the diagonal length of the effective imaging area of ​​the optical system on the imaging plane, f6 is the effective focal length of the sixth lens, f7 is the effective focal length of the seventh lens, TTL is the distance from the object side surface of the first lens to the imaging plane of the optical system on the optical axis, f is the effective focal length of the optical system, R11 is the curvature radius of the object side surface of the sixth lens at the optical axis, and R12 is the curvature radius of the image side surface of the sixth lens at the optical axis.

2. The optical system according to claim 1, characterized in that The following relations are satisfied: 0.14≤sin(FOV) / TTL<0.2; Wherein, FOV is the maximum field of view of the optical system, and the unit of TTL is mm.

3. The optical system according to claim 1, characterized in that The following relations are satisfied: 0.24≤Fno / TTL<0.5; Wherein, Fno is the aperture number of the optical system, and the unit of TTL is mm.

4. The optical system according to claim 1, characterized in that The following relations are satisfied: 0.1≤BFL / TTL≤0.14; Wherein, BFL is the shortest distance from the image side surface of the eighth lens to the imaging surface of the optical system in a direction parallel to the optical axis.

5. A camera module, characterized in that: The optical system comprises a photosensitive element and any one of claims 1 to 4, wherein the photosensitive element is arranged on the image side of the optical system.

6. An electronic device, characterized in that: It comprises a fixing part and the camera module as claimed in claim 5, wherein the camera module is arranged on the fixing part.

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