Optical systems, lens modules and electronic devices

Abstract

An optical system, a lens module, and an electronic device. The optical system is composed of a first lens to an eighth lens in sequence from the object side to the image side. The object side surface and the image side surface of the first lens are convex and concave respectively near the optical axis; the object side surface and the image side surface of the second lens are convex and concave respectively near the optical axis; the object side surface and the image side surface of the third lens are both concave near the optical axis; the object side surface and the image side surface of the fourth lens are both convex near the optical axis; the object side surface and the image side surface of the fifth lens are convex and concave respectively near the optical axis; the object side surface and the image side surface of the sixth lens are convex and concave respectively near the optical axis; the object side surface and the image side surface of the seventh lens are both convex near the optical axis; the object side surface and the image side surface of the eighth lens are convex and concave respectively near the optical axis; the optical system satisfies the following conditional formula: 3.5 < R52 / R51 < 4.5. Through the reasonable design of the eight lenses, the above optical system can correct the aberration of the optical system and improve the imaging quality of the optical system.

Description

Technical Field

[0001] This application relates to the field of optical imaging technology, and particularly relates to an optical system, a lens module and an electronic device. Background Art

[0002] In recent years, with the rise of portable electronic products with photographic functions, the demand for optical systems has been increasing day by day, especially for optical systems applied to action cameras. For traditional optical systems mounted on action cameras, an eight-lens structure is mostly adopted. However, in such an optical system, due to the large number of lenses, when the surface configuration of the lenses is unreasonable, the aberration is likely to be large, resulting in poor imaging quality. Summary of the Invention

[0003] In view of the above, it is necessary to provide an optical system, a lens module and an electronic device to solve the technical problems of large aberration and poor imaging quality when the surface configuration of multiple lenses is unreasonable.

[0004] An embodiment of this application provides an optical system, which is composed of a first lens with negative refractive power, a second lens with negative refractive power, a third lens with negative refractive power, a fourth lens with positive refractive power, a fifth lens with positive refractive power, a sixth lens with refractive power, a seventh lens with positive refractive power and an eighth lens with positive refractive power in sequence from the object side to the image side; the object side surface of the first lens is convex near the optical axis, and the image side surface of the first lens is concave near the optical axis; the object side surface of the second lens is convex near the optical axis, and the image side surface of the second lens is concave near the optical axis; the object side surface of the third lens is concave near the optical axis, and the image side surface of the third lens is concave near the optical axis; the object side surface of the fourth lens is convex near the optical axis, and the image side surface of the fourth lens is convex near the optical axis; the object side surface of the fifth lens is convex near the optical axis, and the image side surface of the fifth lens is concave near the optical axis; the object side surface of the sixth lens is convex near the optical axis, and the image side surface of the sixth lens is concave near the optical axis; the object side surface of the seventh lens is convex near the optical axis, and the image side surface of the seventh lens is convex near the optical axis; the object side surface of the eighth lens is convex near the optical axis, and the image side surface of the eighth lens is concave near the optical axis; the optical system satisfies the following conditional formula: 3.5 < R52 / R51 < 4.5; where, R51 is the curvature radius of the object side surface of the fifth lens at the optical axis, and R52 is the curvature radius of the image side surface of the fifth lens at the optical axis.

[0005] The aforementioned optical system, by setting the first lens to have negative refractive power and making its object-side surface convex near the optical axis, can couple as much light as possible into the optical system and maximize the field of view. By making the image-side surface of the first lens concave near the optical axis, it slows down the entry of light into the optical system, allowing the light to transition more smoothly to the second lens and reducing the sensitivity of the optical system. By setting the second lens to have negative refractive power and making its object-side surface convex near the optical axis, in conjunction with the first lens, it further slows down the entry of light into the optical system and moves the light towards the imaging plane, ensuring a better transition between the light exiting the first lens and the light entering the third lens, reducing the sensitivity of the optical system and improving the assembly yield. By setting the third lens to have negative refractive power, it can be combined with a fourth lens with both positive and negative refractive powers to move the light towards the imaging plane, thereby reducing chromatic aberration and improving the performance of the optical system. By setting the fifth lens to have positive refractive power and making its object-side surface convex near the optical axis and its image-side surface concave near the optical axis, more light can pass through, improving the relative illumination of the optical system. By setting the image-side surface of the sixth lens to be concave near the optical axis and combining it with a seventh lens having positive refractive power, chromatic aberration of the optical system can be further corrected, improving the overall performance of the optical system. By setting the image-side surface of the seventh lens to be convex near the optical axis and combining it with an eighth lens having positive refractive power, the image height of the optical system can be effectively increased, while ensuring the imaging quality of the edge field of view. By setting the image-side surface of the eighth lens to be concave near the optical axis, the incident angle of the principal ray incident on the surface of the photosensitive element, such as the photosensitive chip, can be effectively increased. Furthermore, by making the fifth lens satisfy the above-mentioned relationship, the surface shape of the fifth lens can be prevented from being too flat or excessively curved, which is beneficial for the fifth lens to correct the aberrations of the optical system and improve the imaging quality of the optical system.

[0006] In some embodiments, the optical system satisfies the following condition: 1.6mm < (R12 * SD11) / R1 < 1.9mm; where R11 is the radius of curvature of the object side of the first lens at the optical axis, R12 is the radius of curvature of the image side of the first lens at the optical axis, and SD1 is half of the effective optical diameter of the object side of the first lens.

[0007] In this way, the surface shape and aperture of the first lens are rationally configured, which helps to increase the center thickness of the first lens. This provides sufficient optical path deflection space for large-angle incident light rays, facilitating the smooth convergence of light rays incident at large angles within the first lens, thereby effectively controlling spherical aberration. Furthermore, when the center thickness of the first lens is greater than 1.5mm, the optical system can meet the product evaluation standards in drop tests, impact tests, or other tests while exhibiting good image quality.

[0008] In some embodiments, the optical system satisfies the following conditions: 1.1mm < (R61*R81) / R52 < 1.5mm, 8mm < (F8*R82) / R81 < 20mm; where R61 is the radius of curvature of the object side of the sixth lens at the optical axis, R81 is the radius of curvature of the object side of the eighth lens at the optical axis, R82 is the radius of curvature of the image side of the eighth lens at the optical axis, and F8 is the focal length of the eighth lens.

[0009] In this way, the ghosting generated between these three surfaces and the photosensitive element can be effectively controlled, ensuring that the optical system has good image quality while reducing the risk of ghosting; and the angle of edge light incident on the surface of the photosensitive element can be effectively controlled within a reasonable range, so that the optical system and the photosensitive element have a good match and avoid the risk of color cast in the image.

[0010] In some embodiments, the optical system satisfies the following condition: 1.2 < (V7 - V6) / (V3 - V4) < 1.7; where V3 is the Abbe number of the third lens, V4 is the Abbe number of the fourth lens, V6 is the Abbe number of the sixth lens, and V7 is the Abbe number of the seventh lens.

[0011] In this way, chromatic aberration in the optical system can be effectively controlled, thereby improving the imaging quality of the optical system.

[0012] In some embodiments, the optical system satisfies the following condition: 12mm -1 <R21 / (CT2*ET2)<14mm -1 Where R21 is the radius of curvature of the object side of the second lens at the optical axis, CT2 is the center thickness of the second lens, and ET2 is the distance from the maximum effective aperture of the object side of the second lens to the maximum effective aperture of the image side of the second lens along the optical axis.

[0013] In this way, not only can the field curvature at the edge of the field of view be reduced, but the distortion of the optical system can also be effectively controlled.

[0014] In some embodiments, the optical system satisfies the following conditional formula: -5 mm < F3 / N3 < -4 mm; where N3 is the refractive index of the third lens, and F3 is the focal length of the third lens.

[0015] In this way, the defocus amount of the third lens at high and low temperatures can be effectively controlled, ensuring the imaging quality of the optical system in high and low temperature environments.

[0016] In some embodiments, the optical system satisfies the following relational formula: 0.3 < (CT3 + CT4 + CT5 + CT6 + CT7) / TTL < 0.4; where CT3 is the distance on the optical axis from the object side surface of the third lens to the image side surface of the third lens, CT4 is the distance on the optical axis from the object side surface of the fourth lens to the image side surface of the fourth lens, CT5 is the distance on the optical axis from the object side surface of the fifth lens to the image side surface of the fifth lens, CT6 is the distance on the optical axis from the object side surface of the sixth lens to the image side surface of the sixth lens, CT7 is the distance on the optical axis from the object side surface of the seventh lens to the image side surface of the seventh 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.

[0017] In this way, the relationship between the total length of the optical system and the lens thickness can be effectively controlled, and the thickness tolerance of the optical system can be ensured to have a low sensitivity, improving the assembly yield. When exceeding the upper limit of the relational formula, the optical total length of the optical system is too small, the thickness and spacing of the lenses are too compact, which is not conducive to the assembly of the lenses and reduces the assembly yield of the optical system; when lower than the lower limit of the relational formula, the optical total length of the optical system is too large, which is not conducive to the miniaturization of the optical system.

[0018] In some embodiments, the optical system satisfies the following conditional formula: -1.5 < F / (F2 + F3 + F4 + F5) < -1; where F2 is the focal length of the second lens, F3 is the focal length of the third lens, F4 is the focal length of the fourth lens, F5 is the focal length of the fifth lens, and F is the focal length of the optical system.

[0019] In this way, the depth of field of the optical system can be effectively controlled. It can not only ensure that the optical system can form a clear image when the object distance is greater than 10 m, but also ensure that the optical system can form a clear image when the object distance is less than 0.6 m.

[0020] An embodiment of the present application further provides a lens module, including the optical system and a photosensitive element as described above. The photosensitive element is disposed on the image side of the optical system. The lens module with the above optical system has good imaging quality.

[0021] One embodiment of this application also provides an electronic device, including a lens module and a housing as described above, wherein the lens module is disposed within the housing. The electronic device having the above-described lens module exhibits good image quality. Attached Figure Description

[0022] Figure 1 This is a schematic diagram of the optical system according to the first embodiment of this application.

[0023] Figure 2 This is a schematic diagram of the spherical aberration, astigmatism, and distortion curves of the optical system according to the first embodiment of this application.

[0024] Figure 3 This is a schematic diagram of the optical system according to the second embodiment of this application.

[0025] Figure 4 This is a schematic diagram of the spherical aberration, astigmatism, and distortion curves of the optical system according to the second embodiment of this application.

[0026] Figure 5 This is a schematic diagram of the optical system according to the third embodiment of this application.

[0027] Figure 6 This is a schematic diagram of the spherical aberration, astigmatism, and distortion curves of the optical system according to the third embodiment of this application.

[0028] Figure 7 This is a schematic diagram of the optical system according to the fourth embodiment of this application.

[0029] Figure 8 This is a schematic diagram of the spherical aberration, astigmatism, and distortion curves of the optical system according to the fourth embodiment of this application.

[0030] Figure 9 This is a structural diagram of the optical system according to the fifth embodiment of this application.

[0031] Figure 10 This is a schematic diagram of the spherical aberration, astigmatism, and distortion curves of the optical system according to the fifth embodiment of this application.

[0032] Figure 11 This is a schematic diagram of the structure of a lens module according to an embodiment of this application.

[0033] Figure 12 This is a three-dimensional structural schematic diagram of an electronic device according to an embodiment of this application.

[0034] Explanation of main component symbols

[0035] Optical System 10

[0036] First lens L1

[0037] Second lens L2

[0038] Third lens L3

[0039] Fourth lens L4

[0040] Fifth lens L5

[0041] Sixth lens L6

[0042] Seventh lens L7

[0043] Eighth lens L8

[0044] L9 filter

[0045] STO aperture

[0046] Side surfaces S1, S3, S5, S7, S9, S11, S13, S15, S17

[0047] Like the side views S2, S4, S6, S8, S10, S12, S14, S16, S18

[0048] Imaging plane S19

[0049] Lens tube 20

[0050] Photosensitive element 30

[0051] Lens Module 100

[0052] Casing 200

[0053] 1000 electronic devices Detailed Implementation

[0054] The embodiments of this application are described in detail below. Examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain this application, and should not be construed as limiting this application.

[0055] Please see Figure 1 One embodiment of this application proposes an optical system 10, which consists of 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 in sequence from the object side to the image side along the optical axis.

[0056] The first lens L1 has negative refractive power. Its object-side surface S1 is convex at the optical axis, and its image-side surface S2 is concave at the optical axis. The second lens L2 also has negative refractive power. Its object-side surface S3 is convex at the optical axis, and its image-side surface S4 is concave at the optical axis. The third lens L3 has negative refractive power. Its object-side surface S5 is concave at the optical axis, and its image-side surface S6 is concave at the optical axis. The fourth lens L4 has positive refractive power. Its object-side surface S7 is convex at the optical axis, and its image-side surface S8 is convex at the optical axis. The fifth lens L5 has positive refractive power. Its object-side surface S9 is convex at the optical axis, and its image-side surface S10 is concave at the optical axis. The sixth lens L... Lens L6 has positive or negative refractive power. The object-side surface S11 of the sixth lens L6 is convex at the optical axis, and the image-side surface S12 of the sixth lens L6 is concave at the optical axis. Lens L7 has positive refractive power. The object-side surface S13 of the seventh lens L7 is convex at the optical axis, and the image-side surface S14 of the seventh lens L7 is convex at the optical axis. Lens L8 has positive refractive power. The object-side surface S15 of the eighth lens L8 is convex at the optical axis, and the image-side surface S16 of the eighth lens L8 is concave at the optical axis.

[0057] The above optical system 10 can couple as much light as possible into the optical system 10 by setting the first lens L1 to have a negative refractive power and setting the object surface S1 of the first lens L1 to be convex near the optical axis. At the same time, it can maximize the increase in the field angle of the optical system 10. By setting the image surface S2 of the first lens L1 to be concave near the optical axis, the entry of light into the optical system 10 can be slowed down, making the light transition to the second lens L2 more smoothly and reducing the sensitivity of the optical system 10. By setting the second lens L2 to have a negative refractive power and setting the object surface S3 of the second lens L2 to be convex near the optical axis and cooperating with the first lens L1, the entry of light into the optical system 10 is further slowed down. At the same time, the light is moved towards the imaging surface S19, ensuring a good transition for the light coming out of the first lens L1 and the light entering the third lens L3, reducing the sensitivity of the optical system 10, and improving the assembly yield of the optical system 10. By setting the third lens L3 to have a negative refractive power, it can cooperate with the fourth lens L4 having positive and negative refractive powers to move the light towards the imaging surface S19, thereby reducing the chromatic aberration of the optical system 10 and improving the performance of the optical system 10. By setting the fifth lens L5 to have a positive refractive power and setting the object surface S9 of the fifth lens L5 to be convex near the optical axis and the image surface S10 of the fifth lens L5 to be concave near the optical axis, more light can pass through, improving the relative illumination of the optical system 10. By setting the image surface S12 of the sixth lens L6 to be concave near the optical axis and cooperating with the seventh lens L7 having a positive refractive power, the chromatic aberration of the optical system 10 can be further corrected, improving the overall performance of the optical system 10. By setting the image surface S14 of the seventh lens L7 to be convex near the optical axis and cooperating with the eighth lens L8 having a positive refractive power, the image height of the optical system 10 can be effectively increased, and the imaging quality of the marginal field of view can be ensured. By setting the image surface S16 of the eighth lens L8 to be concave near the optical axis, the incident angle of the chief ray incident on the photosensitive element, such as the surface of the photosensitive chip, can be effectively increased.

[0058] The optical system 10 satisfies the following conditional formula: 3.5 < R52 / R51 < 4.5; where, R51 is the radius of curvature of the object surface S9 of the fifth lens L5 at the optical axis, and R52 is the radius of curvature of the image surface S10 of the fifth lens L5 at the optical axis.

[0059] By making the fifth lens L5 satisfy the above relational formula, the surface shape of the fifth lens L5 can be prevented from being too flat or overly curved, which is beneficial for the fifth lens L5 to correct the aberration of the optical system 10 and improve the imaging quality of the optical system 10.

[0060] In some embodiments, the optical system 10 satisfies the following conditional formula:

[0061] 1.6mm < (R12 * SD11) / R1 < 1.9mm;

[0062] Wherein, R11 is the radius of curvature of the object side surface S1 of the first lens L1 at the optical axis, R12 is the radius of curvature of the image side surface S2 of the first lens L1 at the optical axis, and SD1 is half of the effective optical diameter of the object side surface S1 of the first lens L1.

[0063] In this way, the surface shape and aperture of the first lens L1 are rationally configured, which helps to increase the center thickness of the first lens L1. This provides sufficient optical path deflection space for large-angle incident light rays, facilitating the smooth convergence of light rays incident at large angles within the first lens L1, thereby effectively controlling spherical aberration. Furthermore, when the center thickness of the first lens L1 is greater than 1.5mm, the optical system 10 can meet the product judgment standards in drop tests, impact tests, or other tests while exhibiting good image quality.

[0064] In some embodiments, the optical system 10 satisfies the following condition:

[0065] 1.1mm < (R61*R81) / R52 < 1.5mm;

[0066] Wherein, R61 is the radius of curvature of the object side surface S11 of the sixth lens L6 at the optical axis, and R81 is the radius of curvature of the object side surface S15 of the eighth lens L8 at the optical axis.

[0067] In this way, the ghost images generated between these three surfaces (the image side S10 of the fifth lens L5, the object side S11 of the sixth lens L6, and the object side S15 of the eighth lens L8) and the photosensitive element can be effectively controlled, ensuring that the optical system 10 has good imaging quality while reducing the risk of ghosting.

[0068] In some embodiments, the optical system 10 satisfies the following condition:

[0069] 8mm < (F8*R82) / R81 < 20mm;

[0070] Where R82 is the radius of curvature of the image side surface S16 of the eighth lens L8 at the optical axis, and F8 is the focal length of the eighth lens L8.

[0071] In this way, the angle at which edge light rays are incident on the surface of the photosensitive element can be effectively controlled within a reasonable range, thereby ensuring a good match between the optical system 10 and the photosensitive element and avoiding the risk of color distortion in the image.

[0072] In some embodiments, the optical system 10 satisfies the following condition:

[0073] 1.2 < (V7 - V6) / (V3 - V4) < 1.7;

[0074] Wherein, V3 is the Abbe number of the third lens L3, V4 is the Abbe number of the fourth lens L4, V6 is the Abbe number of the sixth lens L6, and V7 is the Abbe number of the seventh lens L7.

[0075] In this way, the chromatic aberration of the optical system 10 can be effectively controlled, thereby improving the imaging quality of the optical system 10.

[0076] In some embodiments, the optical system 10 satisfies the following condition:

[0077] 12mm -1 <R21 / (CT2*ET2)<14mm -1 ;

[0078] Wherein, R21 is the radius of curvature of the object side surface S3 of the second lens L2 at the optical axis, CT2 is the center thickness of the second lens L2, and ET2 is the distance from the maximum effective aperture of the object side surface S3 of the second lens L2 to the maximum effective aperture of the image side surface S4 of the second lens L2 in the optical axis direction.

[0079] In this way, not only can the field curvature at the edge of the high and low temperature field be reduced, but the distortion of the optical system 10 can also be effectively controlled.

[0080] In some embodiments, the optical system 10 satisfies the following condition:

[0081] -5mm <F3 / N3<-4mm;

[0082] Where N3 is the refractive index of the third lens L3, and F3 is the focal length of the third lens L3.

[0083] In this way, the defocusing amount of the third lens L3 at high and low temperatures can be effectively controlled, ensuring the imaging quality of the optical system 10 under high and low temperature environments.

[0084] In some embodiments, the optical system 10 satisfies the following relationship:

[0085] 0.3<(CT3+CT4+CT5+CT6+CT7) / TTL<0.4;

[0086] Wherein, CT3 is the distance on the optical axis from the object side S5 of the third lens L3 to the image side S6 of the third lens L3; CT4 is the distance on the optical axis from the object side S7 of the fourth lens L4 to the image side S8 of the fourth lens L4; CT5 is the distance on the optical axis from the object side S9 of the fifth lens L5 to the image side S10 of the fifth lens L5; CT6 is the distance on the optical axis from the object side S11 of the sixth lens L6 to the image side S12 of the sixth lens L6; CT7 is the distance on the optical axis from the object side S13 of the seventh lens L7 to the image side S14 of the seventh lens L7; and TTL is the distance on the optical axis from the object side S1 of the first lens L1 to the imaging surface S19 of the optical system 10.

[0087] In this way, the relationship between the total length of the optical system 10 and the lens thickness can be effectively controlled, and the thickness tolerance of the optical system 10 can be kept to a low level, thereby improving the assembly yield. When the upper limit of the relationship is exceeded, the total optical length of the optical system 10 is too small, and the thickness and spacing of the lenses are too compact, which is not conducive to the assembly of the lenses and reduces the assembly yield of the optical system 10; when the lower limit of the relationship is exceeded, the total optical length of the optical system 10 is too large, which is not conducive to the miniaturization of the optical system 10.

[0088] In some embodiments, the optical system 10 satisfies the following condition:

[0089] -1.5 <F / (F2+F3+F4+F5)<-1;

[0090] Wherein, F2 is the focal length of the second lens L2, F3 is the focal length of the third lens L3, F4 is the focal length of the fourth lens L4, F5 is the focal length of the fifth lens L5, and F is the focal length of the optical system 10.

[0091] In this way, the depth of field of the optical system 10 can be effectively controlled, ensuring that the optical system 10 can form a clear image not only when the object distance is greater than 10m, but also when the object distance is less than 0.6m.

[0092] In some embodiments, at least one lens of the optical system 10 has an aspherical surface profile. In one embodiment, both the projection side and the image source side of each lens can be designed aspherical. Aspherical design can help the optical system 10 more effectively eliminate aberrations and improve image quality. In some embodiments, at least one lens in the optical system 10 may also have a spherical surface profile. The spherical surface profile design can reduce the difficulty and cost of lens fabrication. In some embodiments, in order to balance fabrication cost, fabrication difficulty, image quality, assembly difficulty, etc., the surface design of each lens in the optical system 10 can be a combination of aspherical and spherical surface profiles.

[0093] The surface shape of aspherical surfaces can be calculated using the aspherical formula:

[0094]

[0095] Where Z is the distance from the corresponding point on the aspherical surface to the tangent plane of the surface at the optical axis O, r is the distance from the corresponding point on the aspherical surface to the optical axis O, c is the curvature of the aspherical surface at the optical axis O, k is the conic coefficient, and Ai is the coefficient of the higher-order term corresponding to the i-th higher-order term in the aspherical surface shape formula.

[0096] The optical system 10 of this application will be described below through more specific embodiments:

[0097] First Embodiment

[0098] Please see Figure 1 and Figure 2 In the optical system 10 of this embodiment, the first lens L1, 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 are arranged sequentially from the object side to the image side along the optical axis.

[0099] The first lens L1 has negative refractive power. Its object-side surface S1 is convex at the optical axis, and its image-side surface S2 is concave at the optical axis. The second lens L2 has negative refractive power. Its object-side surface S3 is convex at the optical axis, and its image-side surface S4 is concave at the optical axis. The third lens L3 has negative refractive power. Its object-side surface S5 is concave at the optical axis, and its image-side surface S6 is concave at the optical axis. The fourth lens L4 has positive refractive power. Its object-side surface S7 is convex at the optical axis, and its image-side surface S8 is convex at the optical axis. The fifth lens L5 has positive refractive power. Its object-side surface S9 is convex at the optical axis, and its image-side surface S10 is concave at the optical axis. The sixth lens L4... Lens L6 has negative refractive power. The object-side surface S11 of the sixth lens L6 is convex at the optical axis, and the image-side surface S12 of the sixth lens L6 is concave at the optical axis. Lens L7 has positive refractive power. The object-side surface S13 of the seventh lens L7 is convex at the optical axis, and the image-side surface S14 of the seventh lens L7 is convex at the optical axis. Lens L8 has positive refractive power. The object-side surface S15 of the eighth lens L8 is convex at the optical axis, and the image-side surface S16 of the eighth lens L8 is concave at the optical axis.

[0100] In this embodiment, the third lens L3 and the fourth lens L4 are cemented together, so the image-side surface S6 of the third lens L3 coincides with the object-side surface S7 of the fourth lens L4; the sixth lens L6 and the seventh lens L7 are cemented together, so the image-side surface S12 of the sixth lens L6 coincides with the object-side surface S13 of the seventh lens L7.

[0101] In addition, the optical system 10 also includes an aperture stop STO. In this embodiment, the aperture stop STO is placed between the fifth lens L5 and the sixth lens L6. In other embodiments, the aperture stop STO can also be placed between any two lenses or on any lens surface. The optical system 10 also includes a filter L9 and an imaging surface S19. The filter L9 is disposed between the image-side surface S16 of the eighth lens L8 and the imaging surface S19. The filter L9 includes an object-side surface S17 and an image-side surface S18. The filter L9 is used to filter out infrared light. The filter L9 is made of glass and can be coated with a film. The effective pixel area of ​​the photosensitive element 30 is located on the imaging surface S19.

[0102] Table 1a shows the characteristics of the optical system 10 of this embodiment, wherein the focal length, material refractive index and Abbe number are obtained from visible light with a reference wavelength of 555 nm, the Y radius, thickness and focal length are all in millimeters (mm), and the positive and negative values ​​only represent the direction.

[0103] Table 1a

[0104]

[0105] Where F is the focal length of the optical system 10, FNO is the aperture number of the optical system 10, Semi-FOV is half of the maximum field of view 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.

[0106] Table 1b below shows the aspherical coefficients of the corresponding lens surfaces in Table 1a.

[0107] Table 1b

[0108] K A4 A6 A8 A10 A12 A14 A16 S9 6.8133E-01 -1.3519E-03 5.3434E-04 -4.7729E-05 1.4350E-04 0.0000E+00 0.0000E+00 0.0000E+00 S10 -1.1397E+00 3.7190E-02 9.9839E-03 1.3254E-04 5.8136E-04 0.0000E+00 0.0000E+00 0.0000E+00 S14 2.0662E+01 -6.7431E-02 4.3022E-02 -9.9995E-03 4.5123E-03 -6.3195E-04 8.4258E-05 1.8943E-05 S15 2.6156E-01 -9.3854E-02 2.0859E-02 -7.4319E-03 1.3860E-04 3.0982E-04 -2.0687E-06 0.0000E+00 S16 -8.8806E+00 3.5482E-02 -3.9212E-02 1.8269E-02 -5.3323E-03 7.0707E-04 1.3273E-05 -7.3289E-06

[0109] Please see Figure 2 , Figure 2 Figure (a) shows the longitudinal spherical aberration curves of the optical system 10 of the first embodiment at wavelengths of 435 nm, 470 nm, 510 nm, 555 nm, 610 nm, and 656 nm. The horizontal axis along the X-axis represents the focal point shift, and the vertical axis along the Y-axis represents the normalized field of view. The longitudinal spherical aberration curves represent the deviation of the focal point after light of different wavelengths passes through the lenses of the optical system 10. Figure 2 As can be seen from (a), the spherical aberration value of the optical system 10 in the first embodiment is better, indicating that the imaging quality of the optical system 10 in this embodiment is better.

[0110] Figure 2Figure (b) also shows the astigmatism curve of the optical system 10 of the first embodiment at a wavelength of 555 nm, where the horizontal axis along the X-axis represents the focus shift and the vertical axis along the Y-axis represents the field of view angle, both in degrees. The astigmatism curve represents the meridional imaging plane curvature T and the sagittal imaging plane curvature S. Figure 2 As can be seen in (b), the astigmatism of the optical system 10 is well compensated.

[0111] Figure 2 Image (c) also shows the distortion curve of the optical system 10 of the first embodiment at a wavelength of 555 nm. The horizontal axis along the X-axis represents the focus shift, and the vertical axis along the Y-axis represents the field of view, both in degrees. The distortion curve represents the distortion magnitude corresponding to different field of view angles. Figure 2 As can be seen in (c), the distortion of the optical system 10 is well corrected at a wavelength of 555nm.

[0112] Depend on Figure 2 As can be seen from (a), (b) and (c), the optical system 10 of this embodiment has small aberrations, good imaging quality, and excellent imaging performance.

[0113] Please see Figure 3 and Figure 4 The structure of the optical system 10 in the second embodiment is the same as that in the first embodiment, and can be referred to accordingly.

[0114] Table 2a shows the characteristics of the optical system 10 in this embodiment. The focal length, material refractive index and Abbe number are obtained from visible light with a reference wavelength of 555 nm. The units of Y radius, thickness and focal length are millimeters (mm). The positive and negative values ​​only represent the direction. The meanings of the other parameters are the same as those of the parameters in the first embodiment.

[0115] Table 2a

[0116]

[0117]

[0118] Table 2b

[0119] K A4 A6 A8 A10 A12 A14 A16 S9 6.9162E-01 -1.2782E-03 5.9476E-04 -3.1057E-05 1.3808E-04 0.0000E+00 0.0000E+00 0.0000E+00 S10 7.5103E-01 3.6688E-02 9.3052E-04 1.5879E-03 4.5774E-03 0.0000E+00 0.0000E+00 0.0000E+00 S14 7.8940E-01 -5.5610E-02 2.8289E-02 -1.1055E-02 1.7306E-03 -2.0993E-04 -1.4631E-05 8.6940E-06 S15 6.2174E-01 -8.1387E-02 1.2016E-02 -2.8206E-04 -8.1243E-04 3.1551E-04 0.0000E+00 0.0000E+00 S16 -1.2907E+01 3.7823E-02 -4.0476E-02 1.8986E-02 -5.4596E-03 7.1385E-04 9.9833E-06 -6.9995E-06

[0120] Figure 4 The longitudinal spherical aberration curve, astigmatism curve, and distortion curve of the optical system 10 of the second embodiment are shown. The longitudinal spherical aberration curve represents the deviation of the focal point of light rays of different wavelengths after passing through the lenses of the optical system 10; the astigmatism curve represents the curvature of the meridional and sagittal imaging planes; and the distortion curve represents the magnitude of distortion corresponding to different field of view angles. Figure 4As can be seen from the aberration diagram, the longitudinal spherical aberration, field curvature, and distortion of the optical system 10 are all well controlled, thus the optical system 10 of this embodiment has good imaging quality.

[0121] Third Embodiment

[0122] Please see Figure 5 and Figure 6 In the optical system 10 of this embodiment, the first lens L1, 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 are arranged sequentially from the object side to the image side along the optical axis.

[0123] The first lens L1 has negative refractive power. Its object-side surface S1 is convex at the optical axis, and its image-side surface S2 is concave at the optical axis. The second lens L2 has negative refractive power. Its object-side surface S3 is convex at the optical axis, and its image-side surface S4 is concave at the optical axis. The third lens L3 has negative refractive power. Its object-side surface S5 is concave at the optical axis, and its image-side surface S6 is concave at the optical axis. The fourth lens L4 has positive refractive power. Its object-side surface S7 is convex at the optical axis, and its image-side surface S8 is convex at the optical axis. The fifth lens L5 has positive refractive power. Its object-side surface S9 is convex at the optical axis, and its image-side surface S10 is concave at the optical axis. The sixth lens L4... Lens L6 has positive refractive power. The object-side surface S11 of the sixth lens L6 is convex at the optical axis, and the image-side surface S12 of the sixth lens L6 is concave at the optical axis. Lens L7 has positive refractive power. The object-side surface S13 of the seventh lens L7 is convex at the optical axis, and the image-side surface S14 of the seventh lens L7 is convex at the optical axis. Lens L8 has positive refractive power. The object-side surface S15 of the eighth lens L8 is convex at the optical axis, and the image-side surface S16 of the eighth lens L8 is concave at the optical axis.

[0124] In this embodiment, the third lens L3 and the fourth lens L4 are cemented together, so the image-side surface S6 of the third lens L3 coincides with the object-side surface S7 of the fourth lens L4. The sixth lens L6 and the seventh lens L7 are cemented together, so the image-side surface S12 of the sixth lens L6 coincides with the object-side surface S13 of the seventh lens L7.

[0125] The other structures of the third embodiment are the same as those of the first embodiment, and can be referred to accordingly.

[0126] Table 3a shows the characteristics of the optical system 10 in this embodiment. The focal length, material refractive index, and Abbe number are obtained from visible light with a reference wavelength of 555 nm. The units for Y radius, thickness, and focal length are millimeters (mm). The positive and negative values ​​only represent the direction. The meanings of the other parameters are the same as those in the first embodiment.

[0127] Table 3a

[0128]

[0129] Table 3b

[0130] K A4 A6 A8 A10 A12 A14 A16 S9 6.9185E-01 -4.6759E-04 1.7527E-04 1.5203E-04 -4.3048E-05 0.0000E+00 0.0000E+00 0.0000E+00 S10 -7.2906E+00 3.2701E-02 7.1146E-03 1.9894E-03 1.8390E-03 0.0000E+00 0.0000E+00 0.0000E+00 S14 4.8844E+00 -4.3080E-02 2.4457E-02 -8.4832E-03 6.9258E-04 0.0000E+00 0.0000E+00 0.0000E+00 S15 8.3024E-01 -7.9165E-02 9.1476E-03 -2.4286E-03 -1.9780E-04 3.0095E-04 0.0000E+00 0.0000E+00 S16 -1.2696E+01 3.5606E-02 -3.8539E-02 1.8333E-02 -5.4260E-03 7.1388E-04 1.4466E-05 -7.4803E-06

[0131] Figure 6 The longitudinal spherical aberration curve, astigmatism curve, and distortion curve of the optical system 10 of the third embodiment are shown. The longitudinal spherical aberration curve represents the deviation of the focal point of light rays of different wavelengths after passing through the lenses of the optical system 10; the astigmatism curve represents the curvature of the meridional and sagittal imaging planes; and the distortion curve represents the magnitude of distortion corresponding to different field of view angles. Figure 6 As can be seen from the aberration diagram, the longitudinal spherical aberration, field curvature, and distortion of the optical system 10 are all well controlled, thus the optical system 10 of this embodiment has good imaging quality.

[0132] Please see Figure 7 and Figure 8 The structure of the optical system 10 in the fourth embodiment is the same as that in the first embodiment, and can be referred to accordingly.

[0133] Table 4a shows the characteristics of the optical system 10 in this embodiment. The focal length, material refractive index and Abbe number are obtained from visible light with a reference wavelength of 555 nm. The units of Y radius, thickness and focal length are millimeters (mm). The positive and negative values ​​only represent the direction. The meanings of the other parameters are the same as those of the parameters in the first embodiment.

[0134] Table 4a

[0135]

[0136] Table 4b

[0137] K A4 A6 A8 A10 A12 A14 A16 S9 6.8069E-01 -8.8195E-04 7.0833E-04 -7.3506E-05 1.7328E-04 0.0000E+00 0.0000E+00 0.0000E+00 S10 -2.3370E-01 3.6438E-02 8.4814E-03 2.1423E-03 4.0113E-04 0.0000E+00 0.0000E+00 0.0000E+00 S14 1.7508E+00 -6.3714E-02 3.3997E-02 -1.4569E-02 3.1403E-03 -6.3031E-04 8.2965E-05 1.3394E-05 S15 7.1057E-01 -8.8608E-02 1.3335E-02 -3.8867E-04 -7.3000E-04 3.0641E-04 -3.1189E-06 0.0000E+00 S16 -9.2186E+00 3.3376E-02 -3.8596E-02 1.8414E-02 -5.3863E-03 7.0656E-04 1.3134E-05 -7.3121E-06

[0138] Figure 8 The longitudinal spherical aberration curve, astigmatism curve, and distortion curve of the optical system 10 of the fourth embodiment are shown. The longitudinal spherical aberration curve represents the deviation of the focal point of light rays of different wavelengths after passing through the lenses of the optical system 10; the astigmatism curve represents the curvature of the meridional and sagittal imaging planes; and the distortion curve represents the distortion magnitude corresponding to different field of view angles. Figure 8 As can be seen from the aberration diagram, the longitudinal spherical aberration, field curvature, and distortion of the optical system 10 are all well controlled, thus the optical system 10 of this embodiment has good imaging quality.

[0139] Please see Figure 9 and Figure 10 The structure of the optical system 10 in the fifth embodiment is the same as that in the first embodiment, and can be referred to accordingly.

[0140] Table 5a shows the characteristics of the optical system 10 in this embodiment. The focal length, material refractive index and Abbe number are obtained from visible light with a reference wavelength of 555 nm. The units of Y radius, thickness and focal length are millimeters (mm). The positive and negative values ​​only represent the direction. The meanings of the other parameters are the same as those of the parameters in the first embodiment.

[0141] Table 5a

[0142]

[0143] Table 5b

[0144] K A4 A6 A8 A10 A12 A14 A16 S9 6.8069E-01 -8.8195E-04 7.0833E-04 -7.3506E-05 1.7328E-04 0.0000E+00 0.0000E+00 0.0000E+00 S10 -2.3370E-01 3.6438E-02 8.4814E-03 2.1423E-03 4.0113E-04 0.0000E+00 0.0000E+00 0.0000E+00 S14 1.7508E+00 -6.3714E-02 3.3997E-02 -1.4569E-02 3.1403E-03 -6.3031E-04 8.2965E-05 1.3394E-05 S15 7.1057E-01 -8.8608E-02 1.3335E-02 -3.8867E-04 -7.3000E-04 3.0641E-04 -3.1189E-06 0.0000E+00 S16 -9.2186E+00 3.3376E-02 -3.8596E-02 1.8414E-02 -5.3863E-03 7.0656E-04 1.3134E-05 -7.3121E-06

[0145] Figure 10 The longitudinal spherical aberration curve, astigmatism curve, and distortion curve of the optical system 10 of the fifth embodiment are shown. The longitudinal spherical aberration curve represents the deviation of the focal point of light rays of different wavelengths after passing through the lenses of the optical system 10; the astigmatism curve represents the curvature of the meridional and sagittal imaging planes; and the distortion curve represents the distortion magnitude corresponding to different field of view angles. Figure 10 As can be seen from the aberration diagram, the longitudinal spherical aberration, field curvature, and distortion of the optical system 10 are all well controlled, thus the optical system 10 of this embodiment has good imaging quality.

[0146] Table 6 shows the values ​​of R52 / R51, (R12*SD1) / R11, (R61*R81) / R52, (CT3+CT4+CT5+CT6+CT7) / TTL, (F8*R82) / R81, (V7-V6) / (V3-V4), R3 / (CT2*ET2), F3 / N3, and F / (F2+F3+F4+F5) in the optical system 10 of the first to fifth embodiments.

[0147] Table 6

[0148]

[0149]

[0150] In some embodiments, the focal lengths of the first lens L1 to the eighth lens L8 satisfy the formula: -5 < F1 / F < -4, -4 < F2 / F < -3, -6 < F3 / F < -5, 4.5 < F4 / F < 6, 2 < F5 / F < 3, 30 < |F6 / F| < 200, 5.5 < F7 / F < 10, 3 < F8 / F < 10, where F1 is the focal length of the first lens L1, F2 is the focal length of the second lens L2, F3 is the focal length of the third lens L3, F4 is the focal length of the fourth lens L4, F5 is the focal length of the fifth lens L5, F6 is the focal length of the sixth lens L6, F7 is the focal length of the seventh lens L7, F8 is the focal length of the eighth lens L8, and F is the focal length of the optical system 10. By satisfying the above formula, the optical power distribution can be made uniform and reasonable, the aberration is easy to correct, and the image quality is good.

[0151] Table 7 shows the values of -5 < F1 / F < -4, -4 < F2 / F < -3, -6 < F3 / F < -5, 4.5 < F4 / F < 6, 2 < F5 / F < 3, 30 < |F6 / F| < 200, 5.5 < F7 / F < 10, 3 < F8 / F < 10 in the optical system 10 of the first embodiment to the fifth embodiment.

[0152] Relationship / Example First Embodiment Second Embodiment Third Embodiment Fourth embodiment Fifth Embodiment -5<F1 / F<-4 -4.759 -4.692 -4.399 -4.731 -4.759 -4<F2 / F<-3 -3.416 -3.440 -3.246 -3.434 -3.334 -6<F3 / F<-5 -5.167 -5.176 -5.114 -5.314 -5.685 4.5<F4 / F<6 5.338 5.395 4.909 5.339 5.639 2<F5 / F<3 2.525 2.511 2.669 2.557 2.505 30<|F6 / F|<200 41.342 32.171 195.735 55.313 43.445 5.5<F7 / F<10 5.910 8.798 9.404 6.841 7.061 3<F8 / F<10 6.891 9.790 9.662 3.727 7.931

[0153] In this embodiment, by reasonably configuring the surface types of the first lens L1 to the eighth lens L8 and satisfying the above formula, the operating temperature of the optical system 10 can be -40°C to 80°C, the aperture number is between 1.8 and 2, half of the maximum field angle is greater than or equal to 200 degrees, and the total length is less than or equal to 13.5 m.

[0154] Please refer to Figure 11 , an embodiment of the present application further provides a lens module 100, including the optical system 10, a lens barrel 20, and a photosensitive element 30 as described above. The first lens L1 to the eighth lens L8 of the optical system 10 are installed in the lens barrel 20, and the photosensitive element 30 is disposed on the image side of the optical system 10.

[0155] Please refer to Figure 12 , an embodiment of the present application further provides an electronic device 1000, including the lens module 100 and a housing 200 as described above. The lens module 100 is disposed in the housing 200. Optionally, the electronic device 1000 includes, but is not limited to, a sports camera, a mobile phone, etc.

[0156] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present application and are not limitations. Although the present application has been described in detail with reference to the preferred embodiments, those of ordinary skill in the art should understand that the technical solutions of the present application can be modified or equivalently replaced without departing from the spirit and scope of the technical solutions of the present application.

Claims

1. An optical system characterized by, Along the optical axis from the object side to the image side, it consists of a first lens with negative refractive power, a second lens with negative refractive power, a third lens with negative refractive power, a fourth lens with positive refractive power, a fifth lens with positive refractive power, a sixth lens with refractive power, a seventh lens with positive refractive power, and an eighth lens with positive refractive power. The object-side surface of the first lens is convex near the optical axis, and the image-side surface of the first lens is concave near the optical axis. The object-side surface of the second lens is convex near the optical axis, and the image-side surface of the second lens is concave near the optical axis. The object-side surface of the third lens is concave near the optical axis, and the image-side surface of the third lens is concave near the optical axis. The object-side surface of the fourth lens is convex near the optical axis, and the image-side surface of the fourth lens is convex near the optical axis. The object-side surface of the fifth lens is convex near the optical axis, and the image-side surface of the fifth lens is concave near the optical axis. The object-side surface of the sixth lens is convex near the optical axis, and the image-side surface of the sixth lens is concave near the optical axis. The object-side surface of the seventh lens is convex near the optical axis, and the image-side surface of the seventh lens is convex near the optical axis. The object-side surface of the eighth lens is convex near the optical axis, and the image-side surface of the eighth lens is concave near the optical axis. The optical system satisfies the following condition: 3.5 <R52 / R51<4.5; 5.5 <F7 / F<10; Wherein, R51 is the radius of curvature of the object side of the fifth lens at the optical axis, R52 is the radius of curvature of the image side of the fifth lens at the optical axis, F is the focal length of the optical system, and F7 is the focal length of the seventh lens.

2. The optical system of claim 1, wherein, The optical system satisfies the following condition: 1.6mm<(R12*SD1) / R11<1.9mm; Wherein, R11 is the radius of curvature of the object side of the first lens at the optical axis, R12 is the radius of curvature of the image side of the first lens at the optical axis, and SD1 is half of the effective optical diameter of the object side of the first lens.

3. The optical system of claim 2, wherein, The optical system satisfies the following condition: 1.1mm<(R61*R81) / R52<1.5mm, 8mm<(F8*R82) / R81<20mm; Wherein, R61 is the radius of curvature of the object side of the sixth lens at the optical axis, R81 is the radius of curvature of the object side of the eighth lens at the optical axis, R82 is the radius of curvature of the image side of the eighth lens at the optical axis, and F8 is the focal length of the eighth lens.

4. The optical system as claimed in claim 1, characterized in that, The optical system satisfies the following condition: 1.2<(V7-V6) / (V3-V4)<1.7; Wherein, V3 is the Abbe number of the third lens, V4 is the Abbe number of the fourth lens, V6 is the Abbe number of the sixth lens, and V7 is the Abbe number of the seventh lens.

5. The optical system as claimed in claim 1, characterized in that, The optical system satisfies the following condition: 12 mm -1 < R21 / (CT2 * ET2) < 14 mm -1 ; Wherein, R21 is the radius of curvature of the object side of the second lens at the optical axis, CT2 is the center thickness of the second lens, and ET2 is the distance from the maximum effective aperture of the object side of the second lens to the maximum effective aperture of the image side of the second lens along the optical axis.

6. The optical system of claim 1, wherein, The optical system satisfies the following condition: -5mm <F3 / N3<-4mm; Wherein, N3 is the refractive index of the third lens, and F3 is the focal length of the third lens.

7. The optical system of claim 1, wherein, The optical system satisfies the following relationship: 0.3<(CT3+CT4+CT5+CT6+CT7) / TTL<0.4; Wherein, CT3 is the distance on the optical axis from the object side of the third lens to the image side of the third lens, CT4 is the distance on the optical axis from the object side of the fourth lens to the image side of the fourth lens, CT5 is the distance on the optical axis from the object side of the fifth lens to the image side of the fifth lens, CT6 is the distance on the optical axis from the object side of the sixth lens to the image side of the sixth lens, CT7 is the distance on the optical axis from the object side of the seventh lens to the image side of the seventh lens, and TTL is the distance on the optical axis from the object side of the first lens to the imaging surface of the optical system.

8. The optical system of claim 1, wherein, The optical system satisfies the following condition: -1.5 <F / (F2+F3+F4+F5)<-1; Wherein, F2 is the focal length of the second lens, F3 is the focal length of the third lens, F4 is the focal length of the fourth lens, F5 is the focal length of the fifth lens, and F is the focal length of the optical system.

9. A lens module, characterized by, It includes an optical system and a photosensitive element as described in any one of claims 1 to 8, wherein the photosensitive element is disposed on the image side of the optical system.

10. An electronic device, comprising: It includes the lens module and housing as described in claim 9, wherein the lens module is disposed within the housing.

Images