Optical system, camera module and electronic device

Abstract

An optical system, a camera module and an electronic device, eight pieces of lenses with refractive power, the optical system comprises in sequence from the object side to the image side along the optical axis: a first lens with positive refractive power, a third lens, a fifth lens, a seventh lens and a second lens, a fourth lens, an eighth lens with negative refractive power; wherein the object side surface of the first lens, the object side surface of the second lens, the object side surface of the third lens, the object side surface of the fifth lens, the object side surface of the sixth lens and the object side surface of the seventh lens are all convex near the optical axis, the image side surface of the first lens, the image side surface of the second lens, the image side surface of the fourth lens, the image side surface of the sixth lens, the image side surface of the seventh lens, the object side surface of the eighth lens and the image side surface of the eighth lens are all concave near the optical axis, through the reasonable design of each lens of the optical system, the optical system is conducive to meeting miniaturization, having good imaging effect and variable aperture characteristics.

Description

Technical Field

[0001] The present invention belongs to the technical field of optical imaging, and particularly relates to an optical system, an imaging module and an electronic device. Background

[0002] In recent years, electronic devices equipped with cameras have developed rapidly, including portable information terminals such as smartphones, digital cameras, notebook computers, and tablet computers, and people's requirements for imaging quality are also increasing day by day. To enable users to have a better photographing experience and realize shooting of the optical system under different scenarios and requirements, the optical system is required to have a variable aperture function and good imaging effect.

[0003] However, the implementation of the variable aperture and the matching of multiple lenses will lead to a relatively large volume of the optical system, which is difficult to meet the development trend of miniaturization. Summary of the Invention

[0004] The objective of the present invention is to provide an optical system, an imaging module and an electronic device, which solve the problem that the optical system needs to satisfy miniaturization, have good imaging effect and a variable aperture.

[0005] To achieve the above objective, the present invention provides the following technical solutions:

[0006] In a first aspect, the present invention provides an optical system, characterized in that there are a total of eight lenses with refractive power, sequentially arranged from the object side to the image side along the optical axis, including: an adjustable aperture, configured to adjust the aperture size; a first lens, having positive refractive power, with its object side surface being convex at the position close to the optical axis, and its image side surface being concave at the position close to the optical axis; a second lens, having negative refractive power, with its object side surface being convex at the position close to the optical axis, and its image side surface being concave at the position close to the optical axis; a third lens, having positive refractive power, with its object side surface being convex at the position close to the optical axis; a fourth lens, having negative refractive power, with its image side surface being concave at the position close to the optical axis; a fifth lens, having positive refractive power, with its object side surface being convex at the position close to the optical axis; a sixth lens, having refractive power, with its object side surface being convex at the position close to the optical axis, and its image side surface being concave at the position close to the optical axis; a seventh lens, having positive refractive power, with its object side surface being convex at the position close to the optical axis, and its image side surface being concave at the position close to the optical axis, and the image side surface of the seventh lens has at least one inflection point; an eighth lens, having negative refractive power, with its object side surface being concave at the position close to the optical axis, and its image side surface being concave at the position close to the optical axis, and the image side surface of the eighth lens has at least one inflection point.

[0007] The optical system satisfies the relational expressions: 73<FOV<95; 1.2<TTL / ImgH<1.6; where TTL is the distance on the optical axis from the object side surface of the first lens to the imaging surface of the optical system, ImgH is half of the image height corresponding to the maximum field of view of the optical system, and FOV is the maximum field of view of the optical system.

[0008] By providing the first lens with positive refractive power, the object-side surface of the first lens being convex at the paraxial region, and the image-side surface of the first lens being concave at the paraxial region, it is beneficial to reduce the incident angle of light on the object-side surface of the first lens, expand the field of view of the optical system, prevent the light from converging too fast when exiting the first lens, transmit the light gently, and contribute to the miniaturization of the optical system; by providing the second lens with negative refractive power, the object-side surface of the second lens being convex at the paraxial region, and the image-side surface of the second lens being concave at the paraxial region, it is beneficial to correct the aberration generated by the first lens and improve the imaging quality; by providing the third lens with positive refractive power, and the object-side surface of the third lens being convex at the paraxial region, the shape of the second lens is adapted to that of the third lens, and aberrations can be corrected again, which is beneficial to transmit light gently and avoid excessive bending of the second lens; by providing the fourth lens with negative refractive power, and the image-side surface of the fourth lens being convex at the paraxial region, it is beneficial to correct distortion, spherical aberration and astigmatism generated by the lenses on the object side of the fourth lens, and reduce the incident angle of gradually expanding light at the fourth lens, so as to improve the light transmittance; by providing the fifth lens with positive refractive power, and the object-side surface of the fifth lens being convex at the paraxial region, it is beneficial to correct distortion, spherical aberration and astigmatism generated by the fourth lens, and reduce the incident angle of gradually expanding light at the fifth lens, so as to improve the light transmittance; the above layout can make the first to fifth lenses as a whole present a quasi-double Gaussian structure, reduce the workload of the sixth to eighth lenses, avoid excessively curved surface profiles, and improve the molding quality of the lenses; the distribution of the sixth lens, the seventh lens and the eighth lens set to negative refractive power, positive refractive power and negative refractive power can effectively eliminate axial chromatic aberration. The surface profile design in which both the object-side surfaces of the sixth lens and the seventh lens are convex at the paraxial region and the image-side surfaces thereof are concave at the paraxial region makes the two surface profiles adapt to each other, avoids mutual interference between the two lenses, reduces the deflection angle of light when transmitting between the two lenses, and improves the transmittance. The design in which both the object-side surface and the image-side surface of the eighth lens are concave at the paraxial region can balance the convergence of light by the sixth lens and the seventh lens, prevent the image from converging too fast, facilitate the formation of off-axis inflection points, and avoid excessively curved lens surface profiles; at least one inflection point is provided on each of the object-side surface and the image-side surface of the seventh lens, and at least one inflection point is provided on each of the object-side surface and the image-side surface of the eighth lens, which is beneficial to correct off-axis aberrations such as field curvature, and suppress the incident angle of light on the imaging surface, thereby improving both the imaging quality and the relative illumination.

[0009] By making the optical system satisfy 1.2<TTL / ImgH<1.6, the ratio of the distance on the optical axis from the object-side surface of the first lens to the imaging surface of the optical system to half of the image height corresponding to the maximum field of view of the optical system is reasonably configured, which is beneficial to improving the resolving power of the optical system in the full field of view and enhancing the imaging quality of the peripheral field of view; at the same time, it is also beneficial to making the optical system have a smaller total optical length and realize the miniaturization feature.

[0010] By making the optical system satisfy 73<FOV<95, the maximum field of view angle of the optical system is controlled within a reasonable range, which can avoid introducing excessive aberrations, and is beneficial to the optical system to achieve the miniaturization characteristic while obtaining a sufficient field of view.

[0011] In a second aspect, the present invention further provides an imaging module, which comprises a photosensitive chip and the optical system according to any one of the implementations of the first aspect, wherein the photosensitive chip is disposed on the image side of the optical system. The photosensitive surface of the photosensitive chip is located on the imaging surface of the optical system, and the light of an object incident on the photosensitive surface through the lens can be converted into an electrical signal of an image. The photosensitive chip may be a Complementary Metal Oxide Semiconductor (CMOS) or a Charge-coupled Device (CCD). The imaging module may be an imaging module integrated on an electronic device, or may be an independent lens. By incorporating the optical system provided by the present invention into the imaging module, the surface shape and refractive power of each lens in the optical system can be reasonably designed, so that the imaging module meets the characteristics of miniaturization, good imaging effect and variable aperture.

[0012] In a third aspect, the present invention further provides an electronic device, which comprises a housing and the imaging module according to the second aspect, wherein the imaging module is disposed inside the housing. The electronic devices include but are not limited to smartphones, computers, smart watches and the like. By incorporating the imaging module provided by the present invention into the electronic device, the electronic device meets the characteristics of miniaturization, good imaging effect and variable aperture. Brief Description of the Drawings

[0013] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required in the description of the embodiments or the prior art. Obviously, the drawings in the following description are only some embodiments of the present invention, and for those of ordinary skill in the art, other drawings can be obtained based on these drawings without any creative effort.

[0014] Figure 1 is a schematic structural diagram of the optical system of the first embodiment in the first aperture state;

[0015] Figure 2 shows Figure 1 the longitudinal spherical aberration curve, astigmatism curve and distortion curve thereof;

[0016] Figure 3 is a schematic structural diagram of the optical system of the first embodiment in the second aperture state;

[0017] Figure 4 It shows Figure 3 Longitudinal spherical aberration curve, astigmatism curve, and distortion curve;

[0018] Figure 5 This is a schematic diagram of the optical system in the third aperture state according to the first embodiment;

[0019] Figure 6 It shows Figure 5 Longitudinal spherical aberration curve, astigmatism curve, and distortion curve;

[0020] Figure 7 This is a schematic diagram of the optical system in the first aperture state according to the second embodiment;

[0021] Figure 8 It shows Figure 7 Longitudinal spherical aberration curve, astigmatism curve, and distortion curve;

[0022] Figure 9 This is a schematic diagram of the optical system in the first aperture state according to the third embodiment;

[0023] Figure 10 It shows Figure 9 Longitudinal spherical aberration curve, astigmatism curve, and distortion curve;

[0024] Figure 11 This is a schematic diagram of the optical system in the first aperture state according to the fourth embodiment;

[0025] Figure 12 It shows Figure 11 Longitudinal spherical aberration curve, astigmatism curve, and distortion curve;

[0026] Figure 13 This is a schematic diagram of the optical system in the first aperture state according to the fifth embodiment;

[0027] Figure 14 It shows Figure 13 Longitudinal spherical aberration curve, astigmatism curve, and distortion curve;

[0028] Figure 15 This is a schematic diagram of the optical system in the first aperture state according to the sixth embodiment;

[0029] Figure 16 It shows Figure 15 Longitudinal spherical aberration curve, astigmatism curve, and distortion curve;

[0030] Figure 17 This is a schematic diagram of the optical system in the first aperture state according to the seventh embodiment;

[0031] Figure 18 It shows Figure 17 Longitudinal spherical aberration curve, astigmatism curve, and distortion curve;

[0032] Figure 19 A schematic diagram of the camera module structure in one embodiment of the present invention is shown;

[0033] Figure 20 A schematic diagram of the structure of an electronic device according to one embodiment of the present invention is shown. Detailed Implementation

[0034] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of them. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0035] In a first aspect, the present invention provides an optical system, characterized in that it comprises eight refractive lenses, sequentially arranged along the optical axis from the object side to the image side: an adjustable aperture for adjusting the aperture size; a first lens having positive refractive power, with its object side convex near the optical axis and its image side concave near the optical axis; a second lens having negative refractive power, with its object side convex near the optical axis and its image side concave near the optical axis; a third lens having positive refractive power, with its object side convex near the optical axis; and a fourth lens having negative refractive power, with its image side convex near the optical axis. The fifth lens has a positive refractive power, and its object-side surface is convex near the optical axis. The sixth lens has a refractive power, and its object-side surface is convex near the optical axis, while its image-side surface is concave near the optical axis. The seventh lens has a positive refractive power, and its object-side surface is convex near the optical axis, while its image-side surface is concave near the optical axis. The image-side surface of the seventh lens has at least one inflection point. The eighth lens has a negative refractive power, and its object-side surface is concave near the optical axis, while its image-side surface is concave near the optical axis. The image-side surface of the eighth lens has at least one inflection point.

[0036] By giving the first lens positive refractive power, and making its object-side surface convex near the optical axis and its image-side surface concave near the optical axis, it is beneficial to reduce the incident angle of light on the object-side surface of the first lens, expand the field of view of the optical system, and prevent light from converging too quickly when exiting the first lens, thus smoothing the light transmission and contributing to the miniaturization of the optical system. By giving the second lens negative refractive power, and making its object-side surface convex near the optical axis and its image-side surface concave near the optical axis, it is beneficial to correct the aberrations generated by the first lens and improve image quality. By giving the third lens positive refractive power, and making its object-side surface convex near the optical axis, the shape of the second lens is adapted to the third lens, and aberrations can be corrected again, which is beneficial to smooth the light transmission and avoid excessive bending of the second lens. By giving the fourth lens negative refractive power, and making its image-side surface convex near the optical axis, it is beneficial to correct the transmission error on the object side of the fourth lens. The first, second, and third lenses are designed to correct distortion, spherical aberration, and astigmatism caused by the fourth lens, and to reduce the incident angle of the gradually expanding light rays at the fourth lens, thereby improving the transmittance. The fifth lens has positive refractive power, and its object-side surface is convex near the optical axis, which helps correct distortion, spherical aberration, and astigmatism caused by the fourth lens, and reduces the incident angle of the gradually expanding light rays at the fifth lens, thus improving transmittance. This arrangement allows the first to fifth lenses to form a near-double Gaussian structure, reducing the workload of the sixth to eighth lenses, avoiding excessively curved surfaces, and improving lens forming quality. The sixth, seventh, and eighth lenses are designed with negative, positive, and negative refractive power distributions, which effectively eliminates on-axis chromatic aberration. The object-side optical axis surfaces of the sixth and seventh lenses are convex, and the image-side optical axis surfaces are concave, ensuring compatibility between the two surfaces, avoiding interference, reducing the deflection angle of light rays during transmission between them, and improving transmittance. The design of the object-side and image-side optical axes of the eighth lens is concave, which balances the convergence of light by the sixth and seventh lenses, prevents the image from converging too quickly, facilitates the formation of off-axis inflection points, and avoids excessive curvature of the lens surface. The seventh lens and the eighth lens both have at least one inflection point on their object-side and image-side surfaces, which helps to correct off-axis aberrations such as field curvature and suppress the incident angle of light on the imaging plane, thereby improving both image quality and relative illumination.

[0037] The optical system satisfies the relational expression: 1.2<TTL / ImgH<1.6, where TTL is the distance on the optical axis from the object side of the first lens to the imaging plane of the optical system, and ImgH is half of the image height corresponding to the maximum field of view of the optical system. Satisfying the above formula enables reasonable configuration of the total length and image height of the optical system, which is beneficial to improving the resolving power of the full field of view of the optical system, enhancing the imaging quality of the marginal field of view, while reducing the total optical length of the optical system to achieve miniaturization. Further, the optical system satisfies the relational expression: 1.24<TTL / ImgH<1.55, for better imaging quality.

[0038] The optical system satisfies the relational expression: 73deg<FOV<95deg, where FOV is the maximum field of view of the optical system. Satisfying the above conditions keeps the maximum field of view of the optical system within a reasonable range, which can avoid introducing excessive aberrations, and is conducive to the optical system achieving sufficient field of view while realizing the miniaturization feature. Further, the optical system satisfies the relational expression: 77deg<FOV<90deg, for better imaging quality.

[0039] In one embodiment, the optical system satisfies the relational expression: 0.8<f1 / f<1.5, where f1 is the effective focal length of the first lens, and f is the effective focal length of the optical system. Satisfying the above relational expression is beneficial to proper matching of the refractive power of the first lens in the optical system, the surface profile design of the first lens is simpler and more flexible, so that the first lens can support a larger field of view and a large aperture; at the same time, it is also beneficial to converge the light incident into the optical system from the first lens, delay the incident angle of the light, reduce aberrations, and simplify the overall aberration correction of the optical system and the balance of imaging quality. Further, the optical system satisfies the relational expression: 0.9<f1 / f<1.4, for better imaging quality.

[0040] In one embodiment, the optical system satisfies the relational expression: f2 / f<-2, where f2 is the effective focal length of the second lens. Satisfying the above relational expression is beneficial to proper matching of the refractive power of the second lens in the optical system, the surface profile design of the second lens is simpler and more flexible, aberrations are reduced, and the overall aberration correction of the optical system and the balance of imaging quality are simplified. Further, the optical system satisfies the relational expression: -11<f2 / f<-2.5, for better imaging quality.

[0041] In one embodiment, the optical system satisfies the relational expression: 3<f3 / f, where f3 is the effective focal length of the third lens. Satisfying the above relational expression is beneficial to proper matching of the refractive power of the third lens in the optical system, the surface profile design of the third lens is simpler and more flexible, aberrations are reduced, and the overall aberration correction of the optical system and the balance of imaging quality are simplified. Further, the optical system satisfies the relational expression: -4<f3 / f, for better imaging quality.

[0042] In one embodiment, the optical system satisfies the relational expression: f4 / f<-1.5, where f4 is the effective focal length of the fourth lens. Satisfying the above relational expression facilitates the fourth lens to cooperate with the aforementioned three lenses to form a Double-Gauss structure, which eliminates aberrations while enabling light to transmit gently to the subsequent lenses. Further, the optical system satisfies the relational expression: -13<f4 / f<-2, which achieves better imaging quality.

[0043] In one embodiment, the optical system satisfies the relational expression: 2<f5 / f, where f5 is the effective focal length of the fifth lens. Satisfying the above relational expression facilitates the fifth lens to gently diffuse the light beam, laying a foundation for subsequent large-image-plane imaging. Further, the optical system satisfies the relational expression: 3<f5 / f<7, which achieves better imaging quality.

[0044] In one embodiment, the optical system satisfies the relational expression: 9<|f6| / f, where f6 is the effective focal length of the sixth lens. Satisfying the above relational expression facilitates the sixth lens to balance the aberrations of the aforementioned lenses and improve the imaging quality. Further, the optical system satisfies the relational expression: 18<|f6| / f, which achieves better imaging quality.

[0045] In one embodiment, the optical system satisfies the relational expression: 1<f7 / f<1.6, where f7 is the effective focal length of the seventh lens. Satisfying the above relational expression facilitates the seventh lens to shorten the back focal length and realize the miniaturized design of the optical system. Further, the optical system satisfies the relational expression: 1.1<f7 / f<1.5, which achieves better imaging quality.

[0046] In one embodiment, the optical system satisfies the relational expression: -1.3<f8 / f<-0.6, where f8 is the effective focal length of the eighth lens. Satisfying the above relational expression facilitates the eighth lens to cooperate with the aforementioned lenses to eliminate chromatic aberration and realize the miniaturized design of the optical system. Further, the optical system satisfies the relational expression: -1.2<f8 / f<-0.7, which achieves better imaging quality.

[0047] Define R 2n-1 as the radius of curvature of the object side of the nth lens at the optical axis, R 2n as the radius of curvature of the image side of the nth lens at the optical axis, where n is any integer from 1 to 8. Specifically, the radius of curvature of the object side of the first lens at the optical axis is R1, the radius of curvature of the image side of the first lens at the optical axis is R2, and so on.

[0048] In one embodiment, the optical system satisfies the relational expression: 0.3<R1 / f<0.7. In one embodiment, the optical system satisfies the relational expression: 1.3<R2 / f<2.6. Satisfying at least one of the above relational expressions is beneficial to keeping the astigmatism of the first lens within a reasonable range, so that the optical system has good imaging quality. Further, the optical system satisfies the relational expression: 0.4<R1 / f<0.55 or 1.45<R2 / f<2.4, which achieves better imaging quality.

[0049] In one embodiment, the optical system satisfies the relational expression: 0.7<R3 / f<2.2. In one embodiment, the optical system satisfies the relational expression: 0.7<R4 / f<1.2. Satisfying at least one of the above relational expressions is beneficial to keeping the astigmatism of the second lens within a reasonable range, and effectively balancing the astigmatism generated by the first lens, so that the optical system has good imaging quality. Further, the optical system satisfies the relational expression: 0.9<R3 / f<2 or 0.8<R4 / f<1, which achieves better imaging quality.

[0050] In one embodiment, the optical system satisfies the relational expression: 2.5<R5 / f<5. In one embodiment, the optical system satisfies the relational expression: 3<|R6| / f. Satisfying at least one of the above relational expressions is beneficial to keeping the surface shape of the third lens within a reasonable range, and effectively balancing the aberrations generated by the first lens and the second lens, so that the optical system has good imaging quality. Further, the optical system satisfies the relational expression: 3<R5 / f<4 or 3.9<|R6| / f, which achieves better imaging quality.

[0051] In one embodiment, the optical system satisfies the relational expression: 2.4<|R7| / f. In one embodiment, the optical system satisfies the relational expression: 1.6<R8 / f<2.5. Satisfying at least one of the above relational expressions is beneficial to keeping the surface shape of the fourth lens within a reasonable range, and facilitates cooperating with the first lens to the third lens to form a Double-Gauss structure, so that the optical system has good imaging quality. Further, the optical system satisfies the relational expression: 2.7<|R7| / f or 1.8<R8 / f<2.3, which achieves better imaging quality.

[0052] In one embodiment, the optical system satisfies the relational expression: 2.3<R9 / f<4. In one embodiment, the optical system satisfies the relational expression: R10 / f<-3. Satisfying at least one of the above relational expressions is beneficial to keeping the refractive power of the fifth lens within a reasonable range, avoiding excessive refractive power of the fifth lens, and gently receiving the light rays from the object side, so that the optical system has good imaging quality. Further, the optical system satisfies the relational expression: 2.6<R9 / f<3.7 or R10 / f<-4, which achieves better imaging quality.

[0053] In one embodiment, the optical system satisfies the relational expression: 1.9<R11 / f<3. In one embodiment, the optical system satisfies the relational expression: 1.7<R12 / f<3. Satisfying at least one of the above relational expressions is beneficial for keeping the surface shape of the sixth lens within a reasonable range, the overall performance is balanced in cooperation with the seventh lens and the eighth lens to correct aberrations, so that the optical system has good imaging quality. Further, the optical system satisfies the relational expression: 2.1<R11 / f<2.8 or 1.9<R12 / f<2.5, which achieves better imaging quality.

[0054] In one embodiment, the optical system satisfies the relational expression: 0.25<R13 / f<0.5. In one embodiment, the optical system satisfies the relational expression: 0.5<R14 / f<1.1. Satisfying at least one of the above relational expressions is beneficial for keeping the surface shape of the seventh lens within a reasonable range, the overall performance is balanced with the sixth lens and the eighth lens to correct aberrations in a matching manner, so that the optical system has good imaging quality. Further, the optical system satisfies the relational expression: 0.3<R13 / f<0.45 or 0.6<R14 / f<0.9, which achieves better imaging quality.

[0055] In one embodiment, the optical system satisfies the relational expression: -7<R15 / f<-2.5. In one embodiment, the optical system satisfies the relational expression: 0.3<R16 / f<0.9. Satisfying at least one of the above relational expressions is beneficial for keeping the surface shape of the eighth lens within a reasonable range, the overall performance is balanced with the sixth lens and the seventh lens to correct aberrations, so that the optical system has good imaging quality. Further, the optical system satisfies the relational expression: -5<R15 / f<-3 or 0.4<R16 / f<0.8, which achieves better imaging quality.

[0056] In one embodiment, the optical system satisfies the relational expression: -10<R15 / R16<-4. Satisfying the above relational expression is beneficial for reasonably configuring the ratio of the curvature radii of the object side and the image side of the eighth lens at the optical axis, so that the difference between the two curvature radii is reasonably set, the refractive power is adjusted within a reasonable range, the deflection angle of full-field light rays in the optical system is reduced, and the generation and correction of aberrations are controlled. Further, the optical system satisfies the relational expression: -8<R15 / R16<-5, which achieves better imaging quality.

[0057] In one embodiment, the optical system satisfies the relational expression: 6<(R11+R12) / (R11-R12). Satisfying the above relational expression is beneficial for effectively correcting the astigmatism of the optical system, the difference between the two surface shapes will not be too large, and the incident angle of light rays on the two surfaces is reduced. Further, the optical system satisfies the relational expression: 9<(R11+R12) / (R11-R12), which achieves better imaging quality.

[0058] In one embodiment, the optical system satisfies the relational expression: 1.15<f12 / f<1.7, where f12 is the combined effective focal length of the first lens and the second lens. Satisfying the above relational expression is beneficial for the mutual regulation of the first lens and the second lens to control aberrations, facilitates receiving light rays incident at a large angle, and controls the incident light rays to enter the optical system gently, thereby reducing the tolerance sensitivity of the optical system. Further, the optical system satisfies the relational expression: 1.35<f12 / f<1.5, which achieves better imaging quality.

[0059] In one embodiment, the optical system satisfies the relational expression: 6<f345 / f, where f345 is the combined effective focal length of the third lens, the fourth lens and the fifth lens. Satisfying the above relational expression is beneficial for the cooperative cooperation from the third lens to the fifth lens to eliminate chromatic aberration step by step, thereby improving the imaging quality. Further, the optical system satisfies the relational expression: 9<f345 / f

[0060] In one embodiment, the optical system satisfies the relational expression: 3<|f678| / f, where f678 is the combined effective focal length of the sixth lens, the seventh lens and the eighth lens. Satisfying the above relational expression is beneficial for the cooperative cooperation from the sixth lens to the eighth lens to eliminate chromatic aberration step by step, and is also beneficial for adjusting the back focal length, and controlling off-axis aberrations and the incident angle of light rays on the imaging plane. Further, the optical system satisfies the relational expression: 3.8<|f678| / f, which achieves better imaging quality.

[0061] In one embodiment, the optical system satisfies the relational expression: 8<FOV / (FNOmax-FNOmin)<37, where FOV is the maximum field of view of the optical system, FNOmax is the maximum F-number of the optical system, and FNOmin is the minimum F-number of the optical system. Satisfying the above relational expression enables the optical system to have a large field of view, and the F-number of the optical system is maintained within a reasonable range, realizing the combined effect of the optical system having a large field of view and a large aperture. The optical system has a reasonable light intake, which improves the overall illuminance of the imaging picture, and makes the optical system suitable for different lighting environments. Further, the optical system satisfies the relational expression: 28<FOV / (FNOmax-FNOmin)<35, which achieves better imaging quality.

[0062] In one embodiment, the optical system satisfies the relational expression: 0.83<DL / TTL<0.92. Wherein, DL is the distance on the optical axis from the object-side surface of the first lens to the image-side surface of the eighth lens, and TTL is the distance on the optical axis from the object-side surface of the first lens to the imaging surface of the optical system. Satisfying the above relational expression is beneficial to a reasonable configuration of the ratio of the distance on the optical axis from the object-side surface of the first lens to the image-side surface of the eighth lens to the distance on the optical axis from the object-side surface of the first lens to the imaging surface of the optical system. On the premise of realizing the miniaturization of the optical system, the distance on the optical axis from the image-side surface of the eighth lens to the imaging surface of the optical system is increased, thereby increasing the layout space at the module structure end. Further, the optical system satisfies the relational expression: 0.85<DL / TTL<0.9, which achieves better imaging quality.

[0063] In one embodiment, the optical system satisfies the relational expression: 1.2<TTL / f<1.32. Satisfying the above relational expression is beneficial to a reasonable configuration of the ratio of the distance on the optical axis from the object-side surface of the first lens to the imaging surface of the optical system to the effective focal length of the optical system, so that the optical system has a smaller total optical length, achieves the miniaturization feature, and also enables the optical system to have a good telephoto effect. Further, the optical system satisfies the relational expression: 1.22<TTL / f<1.3, which achieves better imaging quality.

[0064] In one embodiment, the optical system satisfies the relational expression: 0.7<ImgH / f<1.1. Wherein, ImgH is half of the image height corresponding to the maximum field of view of the optical system. Satisfying the above relational expression makes the refractive power of the optical system for light rays match the size of the image plane, and improves the imaging quality of the optical system. Further, the optical system satisfies the relational expression: 0.82<ImgH / f<1, which achieves better imaging quality.

[0065] In one embodiment, the optical system satisfies the relational expression: 3<f8 / SAG81<7. In one embodiment, the optical system satisfies the relational expression: 3<f8 / SAG82<7; further, the optical system satisfies the relational expression: 3<f8 / SAG82<6.3. Wherein, SAG81 is the sagittal height at the maximum effective aperture of the object-side surface of the eighth lens, and SAG82 is the sagittal height at the maximum effective aperture of the image-side surface of the eighth lens. Satisfying at least one of the above relational expressions enables the effective focal length of the eighth lens and the surface profile of the object-side surface of the eighth lens to be reasonably set, which is beneficial to minimizing chromatic aberration and spherical aberration to the greatest extent and improving the imaging quality of the optical system; at the same time, it is also beneficial to reasonably distribute the refractive power of the eighth lens, enhance the light-gathering capability of the optical system, reduce the total length of the optical system, and realize the miniaturization of the optical system. Further, the optical system satisfies the relational expression: 3.5<f8 / SAG81<5.5, which achieves better imaging quality.

[0066] CTn is defined as the thickness of the n-th lens on the optical axis, where n is any integer from 1 to 8. Specifically, the thickness of the first lens on the optical axis is CT1, the thickness of the second lens on the optical axis is CT2, and so on.

[0067] In one embodiment, the optical system satisfies the relational expression: -7<(SAG81+SAG82) / CT8<-3.5. Satisfying the above relational expression is beneficial to reasonably control the refractive power and thickness of the eighth lens at all positions in the direction perpendicular to the optical axis, avoid the eighth lens being too thick or too thin, reduce the incident angle of light on the object side of the eighth lens, and lower the tolerance sensitivity of the optical system; at the same time, the eighth lens has a plurality of inflection points, which is beneficial to correcting the distortion and field curvature generated by the lens on the object side of the eighth lens, and enabling the refractive power of the plurality of lenses close to the imaging surface of the optical system to be evenly distributed. Further, the optical system satisfies the relational expression: -6.5<(SAG81+SAG82) / CT8<-4, which achieves better imaging quality.

[0068] In one embodiment, the optical system satisfies the relational expression: 0.5<Yc72 / SD72<0.7. Wherein Yc72 is the vertical height from the off-axis vertex of the image side of the seventh lens to the optical axis, and SD72 is the maximum effective aperture of the image side of the seventh lens. Satisfying the above relational expression is beneficial to reasonably control the refractive power and thickness of the seventh lens at all positions in the direction perpendicular to the optical axis, avoid the seventh lens being too thick or too thin, reduce the incident angle of light on the object side of the seventh lens, and lower the tolerance sensitivity of the optical system. Further, the optical system satisfies the relational expression: 0.55<Yc72 / SD72<0.65, which achieves better imaging quality.

[0069] In one embodiment, the optical system satisfies the relational expression: 0.25<Yc82 / SD82<0.45. Wherein Yc82 is the vertical height from the off-axis vertex of the image side of the eighth lens to the optical axis, and SD82 is the maximum effective aperture of the image side of the eighth lens. Satisfying the above relational expression is beneficial to reasonably control the refractive power and thickness of the eighth lens at all positions in the direction perpendicular to the optical axis, avoid the eighth lens being too thick or too thin, reduce the incident angle of light on the object side of the eighth lens, and lower the tolerance sensitivity of the optical system. Further, the optical system satisfies the relational expression: 0.3<Yc82 / SD82<0.4, which achieves better imaging quality.

[0070] In one embodiment, the optical system satisfies the relational expression: 3.5<CT1 / CT2<5.5; satisfying the above relational expression is beneficial to forming a Gauss-like structure. Further, the optical system satisfies the relational expression: 4<CT1 / CT2<5, which achieves better imaging quality.

[0071] In one embodiment, the optical system satisfies the relational expression: 1<CT4 / CT3<1.3. Satisfying the above relational expression is beneficial to forming a Double-Gauss-like structure. Further, the optical system satisfies the relational expression: 1.1<CT4 / CT3<1.2, which achieves better imaging quality.

[0072] In one embodiment, the optical system satisfies the relational expression: 1.5<CT5 / CT4<2.2. Satisfying the above relational expression is beneficial to forming a Double-Gauss-like structure. Further, the optical system satisfies the relational expression: 1.7<CT5 / CT4<2, which achieves better imaging quality.

[0073] In one embodiment, the optical system satisfies the relational expression: 1.15<CT5 / CT6<1.8. Satisfying the above relational expression prevents an excessively large difference in lens sizes, facilitates the gentle transmission of diverging light, avoids introducing excessive aberrations, and is beneficial to the spatial arrangement of the lenses. Further, the optical system satisfies the relational expression: 1.3<CT5 / CT6<1.65, which achieves better imaging quality.

[0074] In one embodiment, the optical system satisfies the relational expression: 0.5<CT8 / CT7<1.1. Satisfying the above relational expression makes the thicknesses of the two lenses compatible, which is beneficial to reducing the overall thickness and avoids a reduction in yield caused by an excessively thin single lens. Further, the optical system satisfies the relational expression: 0.6<CT8 / CT7<0.9, which achieves better imaging quality.

[0075] In one embodiment, the optical system satisfies the relational expression: 0.6<(CT1+CT2) / (CT3+CT4+CT5)<0.9. Satisfying the above relational expression is beneficial to forming a Double-Gauss-like structure. Further, the optical system satisfies the relational expression: 0.7<(CT1+CT2) / (CT3+CT4+CT5)<0.82, which achieves better imaging quality.

[0076] ATnm is defined as the distance on the optical axis between the nth lens and the mth lens, where n is any integer from 1 to 7, and m=n+1. Specifically, the distance on the optical axis between the first lens and the second lens is AT12, and so on.

[0077] In one embodiment, the optical system satisfies the relational expression: 2.1<AT23 / (AT12+AT34)<3.1. Satisfying the above relational expression is beneficial to reasonably controlling the lens gaps, improving the imaging quality and assemblability, and facilitating the formation of a Double-Gauss-like structure. Further, the optical system satisfies the relational expression: 2.3<AT23 / (AT12+AT34)<2.9, which achieves better imaging quality.

[0078] Define ETn as the distance in the optical axis direction from the maximum effective aperture of the object side of the n-th lens to the maximum effective aperture of the image side of the n-th lens, where n is any integer from 1 to 8. Specifically, ET1 is the distance in the optical axis direction from the maximum effective aperture of the object side of the first lens to the maximum effective aperture of the image side of the second lens, and so on.

[0079] In one embodiment, the optical system satisfies the relational expression: 1<ET7 / ET6<1.9. Satisfying the above relational expression is beneficial to the spatial arrangement of the lenses. Further, the optical system satisfies the relational expression: 1.15<ET7 / ET6<1.75, which achieves better imaging quality.

[0080] In one embodiment, the optical system satisfies the relational expression: 1<ET7 / CT7<1.6. Satisfying the above relational expression can avoid an excessively large thickness ratio of the lens. Further, the optical system satisfies the relational expression: 1.1<ET7 / CT7<1.42, which achieves better imaging quality.

[0081] In one embodiment, the optical system satisfies the relational expression: 0.7<AT78 / CT1<1.2. Satisfying the above relational expression is beneficial to improving the space utilization rate and preventing the seventh lens and the eighth lens from being excessively bent. Further, the optical system satisfies the relational expression: 0.85<AT78 / CT1<1, which achieves better imaging quality.

[0082] In some embodiments, the optical system further includes a filter, which may be an infrared cut-off filter or an infrared band-pass filter. The infrared cut-off filter is used to filter out infrared light, and the infrared band-pass filter only allows infrared light to pass through. In the present application, the filter is an infrared cut-off filter, which is arranged to be relatively fixed with each lens in the optical system, and is used to prevent infrared light from reaching the imaging surface of the optical system and interfering with normal imaging. The filter can be assembled together with each lens as a part of the optical system. In other embodiments, the filter may also be an element independent of the optical system, and the filter can be installed between the optical system and the photosensitive chip when the optical system and the photosensitive chip are assembled. It can be understood that the filter may be made of optical glass coated with a film, or made of colored glass, or a filter of other materials. The material of the filter IR may be glass or plastic, which can be selected according to actual needs, and no specific limitation is made in this embodiment. In other embodiments, a filter coating may be provided on at least one of the first lens to the eighth lens to achieve the effect of filtering out infrared light.

[0083] First Embodiment

[0084] Please refer to Figure 1 , Figure 3 and Figure 5 , the optical system 10 sequentially includes along the optical axis 101 direction from the object side to the image side:

[0085] The first lens L1 has positive refractive power, the object side S1 is convex near the optical axis, and the image side S2 is concave near the optical axis.

[0086] The second lens L2 has a negative refractive power, the object-side surface S3 is convex near the optical axis, and the image-side surface S4 is concave near the optical axis.

[0087] The third lens L3 has a positive refractive force, the object-side surface S5 is convex near the optical axis, and the image-side surface S6 is concave near the optical axis.

[0088] The fourth lens L4 has a negative refractive power. The object-side surface S7 is convex near the optical axis, and the image-side surface S8 is convex near the optical axis.

[0089] The fifth lens L5 has positive refractive power, the object side S9 is convex near the optical axis, and the image side S10 is concave near the optical axis.

[0090] The sixth lens L6 has a negative refractive power. The object-side surface S11 is convex near the optical axis, and the image-side surface S12 is concave near the optical axis.

[0091] The seventh lens L7 has positive refractive power. The object-side surface S13 is convex near the optical axis, and the image-side surface S14 is concave near the optical axis.

[0092] The eighth lens L8 has a negative refractive power. The object-side surface S15 is convex near the optical axis, and the image-side surface S16 is concave near the optical axis.

[0093] In addition, the optical system 10 also includes an aperture STO, an IR filter, and an imaging plane IMG, with the aperture STO being a variable aperture.

[0094] In this embodiment, the aperture STO is located on the object-side side of the first lens of the optical system 10 to control the amount of light entering the system. Figure 1 , Figure 3 and Figure 5 Schematic diagrams of the optical system 10 with the aperture STO in three different states are shown. When the aperture STO is in three different states, the optical system 10 can have different aperture numbers. Therefore, for ease of description of the three states of the aperture STO, [the diagrams are then presented]. Figure 1 The aperture STO in the state shown is called the aperture STO of the optical system 10 in the first aperture state. Figure 3 The aperture STO in the state shown is called the aperture STO of the optical system 10 in the second aperture state. Figure 5The aperture STO shown in the diagram is referred to as the aperture STO of the optical system 10 in the third aperture state. It can be understood that the aperture STO includes, but is not limited to, these three states. By adjusting the distance A between the aperture STO and the object side surface S1 of the first lens L1, and the size of the aperture STO opening, the aperture STO can also have other different states, so that the optical system 10 can obtain different aperture numbers.

[0095] An infrared cutoff filter (IR) is positioned between the eighth lens (L8) and the imaging surface (IMG). It includes an object-side surface (S17) and an image-side surface (S18). The IR is an infrared cutoff filter used to filter out infrared light, ensuring that only visible light (wavelength 380nm-780nm) enters the imaging surface (IMG). The IR is made of glass (or plastic), with a coating on its surface. Lenses L1 through L8 are made of plastic (or plastic-glass). The effective pixel area of ​​the image sensor is located on the imaging surface (IMG). The image sensor captures different wavelengths of information about the object for subsequent processing.

[0096] Table 1a shows the parameters of the optical system 10 in this embodiment, with the positive direction from the object side to the image side. The Y-radius is the radius of curvature of the corresponding surface number along the optical axis. In the same lens element, the surface with the smaller surface number is the object side, and vice versa. The value in the "thickness" parameter column is the distance along the optical axis from the current surface to the next surface. The focal length, material refractive index, and Abbe number all use 555.0 nm as the reference wavelength. The units for Y-radius, thickness, and focal length are millimeters (mm).

[0097] Table 1a

[0098]

[0099] Table 1b

[0100] FNO 1.40 2.00 4.00 A -0.38mm 0.38mm 0.38mm

[0101] Where f is the effective focal length of optical system 10, FNO is the aperture number of optical system 10, FOV (°) is the maximum field of view of optical system 10, TTL is the distance from the object side of the first lens to the imaging surface on the optical axis, i.e., the total optical length, and A is the distance from the aperture stop STO to the object side S1 of the first lens L1 in the direction parallel to the optical axis.

[0102] In this embodiment, the object-side surface and image-side surface of the first lens L1 to the eighth lens L8 are both aspherical surfaces. The surface shape x of the aspherical surface can be defined using, but is not limited to, the following aspherical surface formula:

[0103]

[0104] Where x is the distance from the corresponding point on the aspherical surface to the plane tangent to the vertex of the surface, h is the distance from the corresponding point on the aspherical surface to the optical axis, c is the curvature of the vertex of the aspherical surface, k is the conic coefficient, and Ai is the coefficient corresponding to the i-th higher-order term in the aspherical surface shape formula. Table 1c gives the higher-order term coefficients A4, A6, A8, A10, A12, A14, A16, A18, A20, A22, A24, A26, A28, and A30 of the aspherical mirrors S1, S2, S3, S4, S5, S6, S7, S8, S9, S10, S11, S12, S13, S14, S15, and S16 that can be used in the first embodiment.

[0105] Table 1c

[0106]

[0107]

[0108] Figure 2 (First aperture setting) Figure 4 (Second aperture state) and Figure 6 (Third aperture state) shows the longitudinal spherical aberration curve, astigmatism curve, and distortion curve of the optical system 10 in each aperture state in the first embodiment.

[0109] In the longitudinal spherical aberration curve, the horizontal axis represents the focal point offset (mm), which is the distance from the imaging plane to the intersection of the light ray and the optical axis, and the vertical axis represents the normalized field of view. It can be seen that the focal point offset of each wavelength of light in the first embodiment is low, and the blur spots or halos are effectively suppressed, indicating that the optical system 10 in this embodiment has high imaging quality.

[0110] In the astigmatism curve diagram, the horizontal axis represents the focal offset (mm), which is the distance from the imaging plane to the intersection of the ray and the optical axis, and the vertical axis represents the image height (mm). It can be seen that in the first embodiment, the sagittal (S) and meridional (T) converging focal points deviate from the image plane to a low degree, and the difference between the two is small. Astigmatism and field curvature are suppressed, indicating that the optical system 10 in this embodiment has high imaging quality.

[0111] In the distortion curve graph, the horizontal axis represents the distortion (%) and the vertical axis represents the image height (mm). It can be seen that the distortion degree of the reference wavelength light in the first embodiment is low, and the imaging distortion is effectively suppressed, indicating that the imaging quality of the optical system 10 in this embodiment is high.

[0112] Second Embodiment

[0113] Please refer to Figure 7 The overall structure of the optical system 10 in this embodiment is largely the same as that in the first embodiment. For the same content, please refer to Embodiment 1, so it will not be repeated here. Other differences are detailed in the list.

[0114] Table 2a

[0115]

[0116] Table 2b

[0117] FNO 1.40 2.00 4.00 A -0.38mm 0.38mm 0.38mm

[0118] Table 2c gives the higher-order coefficients that can be used for each aspherical mirror in the second embodiment, wherein each aspherical surface shape can be defined by the formula given in the first embodiment.

[0119] Table 2c

[0120]

[0121]

[0122] Figure 8 (In the first aperture state) are shown the longitudinal spherical aberration curve, astigmatism curve, and distortion curve of the optical system 10 of the second embodiment. As can be seen from the figures, the longitudinal spherical aberration, field curvature, and distortion of the optical system 10 are well controlled, thus the optical system 10 of this embodiment has good imaging quality. Considering that reducing the aperture can improve image quality without triggering the diffraction limit, the imaging quality of the optical system 10 of the second embodiment is also excellent in other aperture states.

[0123] Third Embodiment

[0124] Please refer to Figure 9 The overall structure of the optical system 10 in this embodiment is largely the same as that in the first embodiment. For the same content, please refer to Embodiment 1, so it will not be repeated here. Other differences are detailed in the list.

[0125] Table 3a

[0126]

[0127]

[0128] Table 3b

[0129] FNO 1.40 2.00 4.00 A -0.38 0.38 0.38

[0130] Table 3c gives the higher-order coefficients that can be used for each aspherical mirror in the third embodiment, wherein each aspherical surface shape can be defined by the formula given in the first embodiment.

[0131] Table 3c

[0132]

[0133]

[0134] Figure 10 (In the first aperture state) are shown the longitudinal spherical aberration curve, astigmatism curve, and distortion curve of the optical system 10 of the third embodiment. As can be seen from the figures, the longitudinal spherical aberration, field curvature, and distortion of the optical system 10 are well controlled, thus the optical system 10 of this embodiment has good imaging quality. Considering that reducing the aperture can improve image quality without triggering the diffraction limit, the optical system 10 of the third embodiment also has excellent imaging quality in other aperture states.

[0135] Fourth embodiment

[0136] Please refer to Figure 11 The overall structure of the optical system 10 in this embodiment is largely the same as that in the first embodiment. For the same content, please refer to Embodiment 1, so it will not be repeated here. Other differences are detailed in the list.

[0137] Table 4a

[0138]

[0139]

[0140] Table 4b

[0141] FNO 1.40 2.00 4.00 A -0.38 0.38 0.38

[0142] Table 4c gives the higher-order coefficients that can be used for each aspherical mirror in the fourth embodiment, wherein each aspherical surface shape can be defined by the formula given in the first embodiment.

[0143] Table 4c

[0144]

[0145]

[0146] Figure 12 (In the first aperture state) the longitudinal spherical aberration curve, astigmatism curve, and distortion curve of the optical system 10 of the fourth embodiment are shown respectively. As can be seen from the figures, the longitudinal spherical aberration, field curvature, and distortion of the optical system 10 are well controlled, thus the optical system 10 of this embodiment has good imaging quality. Considering that reducing the aperture can improve image quality without triggering the diffraction limit, the imaging quality of the optical system 10 of the fourth embodiment is also excellent in other aperture states.

[0147] Fifth embodiment

[0148] Please refer to Figure 13The overall structure of the optical system 10 in this embodiment is largely the same as that in the first embodiment. For the same content, please refer to Embodiment 1, so it will not be repeated here. Other differences are detailed in the list.

[0149] Table 5a

[0150]

[0151] Table 5b

[0152] FNO 1.40 2.00 4.00 A -0.38 0.38 0.38

[0153] Table 5c gives the higher-order coefficients that can be used for each aspherical mirror in the fifth embodiment, wherein each aspherical surface shape can be defined by the formula given in the first embodiment.

[0154] Table 5c

[0155]

[0156] Figure 14 (In the first aperture state) the longitudinal spherical aberration curve, astigmatism curve, and distortion curve of the optical system 10 of the fifth embodiment are shown respectively. As can be seen from the figures, the longitudinal spherical aberration, field curvature, and distortion of the optical system 10 are well controlled, thus the optical system 10 of this embodiment has good imaging quality. Considering that reducing the aperture can improve image quality without triggering the diffraction limit, the optical system 10 of the fifth embodiment also has excellent imaging quality in other aperture states.

[0157] Sixth Embodiment

[0158] Please refer to Figure 15 The overall structure of the optical system 10 in this embodiment is largely the same as that in the first embodiment. For the same content, please refer to Embodiment 1, so it will not be repeated here. Other differences are detailed in the list.

[0159] Table 6a

[0160]

[0161] Table 6b

[0162] FNO 1.40 2.00 4.00 A -0.38 0.38 0.38

[0163] Table 6c gives the higher-order coefficients that can be used for each aspherical mirror in the sixth embodiment, wherein each aspherical surface shape can be defined by the formula given in the first embodiment.

[0164] Table 6c

[0165]

[0166]

[0167] Figure 16 (In the first aperture state) the longitudinal spherical aberration curve, astigmatism curve, and distortion curve of the optical system 10 of the sixth embodiment are shown respectively. As can be seen from the figures, the longitudinal spherical aberration, field curvature, and distortion of the optical system 10 are well controlled, thus the optical system 10 of this embodiment has good imaging quality. Considering that reducing the aperture can improve image quality without triggering the diffraction limit, the imaging quality of the optical system 10 of the sixth embodiment is also excellent in other aperture states.

[0168] Seventh Embodiment

[0169] Please refer to Figure 17 The overall structure of the optical system 10 in this embodiment is largely the same as that in the first embodiment. For the same content, please refer to Embodiment 1, so it will not be repeated here. Other differences are detailed in the list.

[0170] Table 7a

[0171]

[0172]

[0173] Table 7b

[0174] FNO 1.40 2.00 4.00 A -0.38 0.38 0.38

[0175] Table 7c gives the higher-order coefficients that can be used for each aspherical mirror in the seventh embodiment, wherein each aspherical surface shape can be defined by the formula given in the first embodiment.

[0176] Table 7c

[0177]

[0178]

[0179] Figure 18 (In the first aperture state) The longitudinal spherical aberration, astigmatism, and distortion curves of the optical system 10 of the seventh embodiment are shown respectively. As can be seen from the figures, the longitudinal spherical aberration, field curvature, and distortion of the optical system 10 are well controlled, thus the optical system 10 of this embodiment has good imaging quality. Considering that reducing the aperture can improve image quality without triggering the diffraction limit, the imaging quality of the optical system 10 of the seventh embodiment is also excellent in other aperture states.

[0180] Table 8 shows the values ​​of several relationships in the optical systems of the first to seventh embodiments.

[0181] Table 8

[0182]

[0183]

[0184] Please see Figure 19 The present invention also provides a camera module 20, which includes a photosensitive chip 21 and an optical system 10 as described in any embodiment of the first aspect. The photosensitive chip 21 is disposed on the image side of the optical system 10. The photosensitive surface of the photosensitive chip 21 is located on the imaging surface of the optical system 10, and light rays from an object incident on the photosensitive surface through a lens can be converted into electrical signals for an image. The photosensitive chip 21 can be a complementary metal-oxide-semiconductor (CMOS) or a charge-coupled device (CCD). The camera module 20 can be an imaging module integrated into an electronic device or a standalone lens. By incorporating the optical system 10 provided by the present invention into the camera module 20, the camera module 20 can achieve miniaturization, good imaging performance, and variable aperture characteristics through reasonable design of the surface shape and refractive power of each lens in the optical system 10.

[0185] Please see Figure 20 The present invention also provides an electronic device 30, which includes a housing 31 and the aforementioned camera module 20, wherein the camera module 20 is disposed within the housing 31. This electronic device 30 includes, but is not limited to, smartphones, computers, and smartwatches. By incorporating the camera module 20 provided by the present invention into the electronic device 30, the electronic device 30 achieves miniaturization, good imaging performance, and variable aperture characteristics.

[0186] The above description discloses only some preferred embodiments of the present invention, and should not be construed as limiting the scope of the present invention. Those skilled in the art can understand that implementing all or part of the above embodiments and making equivalent changes in accordance with the claims of the present invention still fall within the scope of the present invention.

Claims

1. An optical system, characterized in that, There are eight lenses with refractive power, arranged in order from the object side to the image side along the optical axis, including: An adjustable aperture stop, capable of adjusting the aperture size; A first lens, having positive refractive power, with its object side surface being convex at the paraxial region, and its image side surface being concave at the paraxial region; A second lens, having negative refractive power, with its object side surface being convex at the paraxial region, and its image side surface being concave at the paraxial region; A third lens, having positive refractive power, with its object side surface being convex at the paraxial region; A fourth lens, having negative refractive power, with its image side surface being concave at the paraxial region; A fifth lens, having positive refractive power, with its object side surface being convex at the paraxial region; A sixth lens, having refractive power, with its object side surface being convex at the paraxial region, and its image side surface being concave at the paraxial region; A seventh lens, having positive refractive power, with its object side surface being convex at the paraxial region, its image side surface being concave at the paraxial region, and the image side surface of the seventh lens having at least one inflection point; An eighth lens, having negative refractive power, with its object side surface being concave at the paraxial region, its image side surface being concave at the paraxial region, and the image side surface of the eighth lens having at least one inflection point; The optical system satisfies the relational expression: 77 deg < FOV < 90 deg ; 1.24 < TTL / ImgH < 1.55; 0.5 < Yc72 / SD72 < 0.7; 0.25 < Yc82 / SD82 < 0.45; 1.15 < f12 / f < 1.7; 6 < f345 / f; 3 < |f678| / f; Wherein, TTL is the distance on the optical axis from the object side surface of the first lens to the image plane of the optical system, ImgH is half of the image height corresponding to the maximum field of view of the optical system, FOV is the maximum field of view of the optical system, Yc72 is the vertical height from the off-axis vertex of the image side surface of the seventh lens to the optical axis, SD72 is the maximum effective aperture of the image side surface of the seventh lens, Yc82 is the vertical height from the off-axis vertex of the image side surface of the eighth lens to the optical axis, SD82 is the maximum effective aperture of the image side surface of the eighth lens, f is the effective focal length of the optical system, f12 is the combined focal length of the first lens and the second lens, f345 is the combined focal length of the third lens, the fourth lens and the fifth lens, and f678 is the combined focal length of the sixth lens, the seventh lens and the eighth lens.

2. The optical system as described in claim 1, characterized in that, The optical system satisfies the relational expression: 0.9 < f1 / f < 1.4, and / or -11 < f2 / f < -2.5, and / or 4.375 ≤ f3 / f , and / or -13 < f4 / f < -2, and / or 3 < f5 / f < 7, and / or 18 < |f6| / f , and / or 1.1 < f7 / f < 1.5, and / or -1.2 < f8 / f < -0.7; where f1 is the effective focal length of the first lens, f2 is the effective focal length of the second lens, f3 is the effective focal length of the third lens, f4 is the effective focal length of the fourth lens, f5 is the effective focal length of the fifth lens, f6 is the effective focal length of the sixth lens, f7 is the effective focal length of the seventh lens, f8 is the effective focal length of the eighth lens, and f is the effective focal length of the optical system.

3. The optical system as described in claim 1, characterized in that, The optical system satisfies the relational expression: 0.4<R1 / f<0.55, and / or 1.45<R2 / f<2.4, and / or 0.9<R3 / f<2, and / or 0.8<R4 / f<1, and / or 3<R5 / f<4, and / or 3.9<|R6| / f , and / or 2.7<|R7| / f , and / or 1.8<R8 / f<2.3, and / or 2.6<R9 / f<3.7, and / or R10 / f<-4, and / or 2.1<R11 / f<2.8, and / or 1.9<R12 / f<2.5, and / or 0.3<R13 / f<0.45, and / or 0.6<R14 / f<0.9, and / or -5<R15 / f<-3, and / or 0.4<R16 / f<0.8, and / or 9<(R11+R12) / (R11-R12), and / or -8<R15 / R16<-5; where R1 is the curvature radius of the object side surface of the first lens at the optical axis, R2 is the curvature radius of the image side surface of the first lens at the optical axis, R3 is the curvature radius of the object side surface of the second lens at the optical axis, R4 is the curvature radius of the image side surface of the second lens at the optical axis, R5 is the curvature radius of the object side surface of the third lens at the optical axis, R6 is the curvature radius of the image side surface of the third lens at the optical axis, R7 is the curvature radius of the object side surface of the fourth lens at the optical axis, R8 is the curvature radius of the image side surface of the fourth lens at the optical axis, R9 is the curvature radius of the object side surface of the fifth lens at the optical axis, R10 is the curvature radius of the image side surface of the fifth lens at the optical axis, R11 is the curvature radius of the object side surface of the sixth lens at the optical axis, R12 is the curvature radius of the image side surface of the sixth lens at the optical axis, R13 is the curvature radius of the object side surface of the seventh lens at the optical axis, R14 is the curvature radius of the image side surface of the seventh lens at the optical axis, R15 is the curvature radius of the object side surface of the eighth lens at the optical axis, R16 is the curvature radius of the image side surface of the eighth lens at the optical axis, and f is the effective focal length of the optical system.

4. The optical system as claimed in claim 1, characterized in that, The optical system satisfies the relational expression: 1.35<f12 / f<1.5, 9<f345 / f, 3.8<|f678| / f.

5. The optical system as claimed in claim 1, characterized in that, The optical system satisfies the relational expression: 28<FOV / (FNOmax-FNOmin)<37, and / or 1.2<TTL / f<1.32, and / or 0.82<ImgH / f<1, and / or 0.83<DL / TTL<0.92; wherein DL is the distance on the optical axis from the object-side surface of the first lens to the image-side surface of the eighth lens, f is the effective focal length of the optical system, FNOmax is the maximum F-number of the optical system, and FNOmin is the minimum F-number of the optical system.

6. The optical system as claimed in claim 1, characterized in that, The optical system satisfies the relational expression: 3.5<f8 / SAG81<5.5, and / or 3<f8 / SAG82<7, and / or -6.5<(SAG81+SAG82) / CT8<-4; wherein f8 is the effective focal length of the eighth lens, SAG81 is the sagittal height at the maximum effective aperture of the object-side surface of the eighth lens, SAG82 is the sagittal height at the maximum effective aperture of the image-side surface of the eighth lens, and CT8 is the thickness of the eighth lens on the optical axis.

7. The optical system as claimed in claim 1, characterized in that, The optical system satisfies the relational expression: 0.55<Yc72 / SD72<0.65; 0.3<Yc82 / SD82<0.

4.

8. The optical system as claimed in claim 1, characterized in that, The optical system satisfies the relational expression: 4<CT1 / CT2<5, and / or 1.1<CT4 / CT3<1.2, and / or 1.7<CT5 / CT4<2, and / or 1.3<CT5 / CT6<1.65, and / or 0.6<CT8 / CT7<0.9, and / or 0.7<(CT1+CT2) / (CT3+CT4+CT5)<0.82, and / or 2.3<AT23 / (AT12+AT34)<2.9, and / or 1.15<ET7 / ET6<1.75, and / or 1.1<ET7 / CT7<1.42, and / or 0.85<AT78 / CT1<1; wherein AT12 is the distance on the optical axis from the image-side surface of the first lens to the object-side surface of the second lens, AT23 is the distance on the optical axis from the image-side surface of the second lens to the object-side surface of the third lens, AT34 is the distance on the optical axis from the image-side surface of the third lens to the object-side surface of the fourth lens, AT78 is the distance on the optical axis from the image-side surface of the seventh lens to the object-side surface of the eighth lens, ET6 is the distance in the optical axis direction from the maximum effective aperture of the object-side surface of the sixth lens to the maximum effective aperture of the image-side surface of the sixth lens, ET7 is the distance in the optical axis direction from the maximum effective aperture of the object-side surface of the seventh lens to the maximum effective aperture of the image-side surface of the seventh lens, CTn is the thickness of the nth lens on the optical axis, n=1,2,3,4,5,6,7,8.

9. A camera module, characterized in that, comprising the optical system according to any one of claims 1 to 8 and a photosensitive chip, wherein the photosensitive chip is located on the image side of the optical system.

10. An electronic device, characterized in that, The electronic device comprises a housing and the camera module according to claim 9, wherein the camera module is disposed in the housing.

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