Optical systems, lens modules and electronic devices

Abstract

The present invention provides an optical system, a lens module, and an electronic device. The optical system sequentially includes, from the object side to the image side along the optical axis direction: a first lens with a negative focal power; a second lens with a positive focal power; a third lens with a negative focal power; a fourth lens with a focal power; a fifth lens with a positive focal power, and at least one inflection point is provided on the object side surface of the fifth lens; a sixth lens with a negative focal power, and at least one inflection point is provided on at least one of the object side surface and the image side surface of the sixth lens; the optical system satisfies the conditional formula: -9 < f4 / |f1| < 3.5. By reasonably configuring the surface types and focal powers of the first lens to the sixth lens, the requirements of good imaging, miniaturization, and large viewing angle are met; at the same time, by reasonably setting the value of f4 / |f1|, the lens focal powers are reasonably distributed and the lens shapes are configured, which is beneficial to expanding the system field of view angle.

Description

Technical Field

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

[0002] With the continuous development of smartphone-related technologies, taking photos has become the most important function of smartphones besides communication. With the application of wide-angle optical lenses and optimized software algorithms, portrait selfies are very stunning, bringing consumers an excellent experience. With the advancement of semiconductor process technology, the pixel size of photosensitive elements has been reduced, and the optical system tends to have higher pixels and higher image quality.

[0003] In order to meet this trend, wide-angle lenses need to have a wider angle and miniaturization while achieving high-quality imaging. Currently, although systems designed with four or five optical lens groups can meet the miniaturization requirements, their lens power configuration is unbalanced, which can easily cause excessive off-axis aberrations that are difficult to correct, resulting in poor efficiency in the electronic photosensitive element receiving light emitted by the object, affecting the imaging quality. Summary of the invention

[0004] The object of the present invention is to provide an optical system that meets the requirements of good imaging, miniaturization and wide viewing angle.

[0005] To achieve the purpose of the present invention, the present invention provides the following technical solutions:

[0006] In a first aspect, the present invention provides an optical system, which sequentially includes, from the object side to the image side along the optical axis direction: a first lens with a negative optical power; a second lens with a positive optical power; a third lens with a negative optical power; a fourth lens with an optical power; a fifth lens with a positive optical power, the object side surface of the fifth lens at the optical axis is convex, the object side surface at the circumference is concave, and at least one inflection point is provided on the object side surface of the fifth lens; a sixth lens with a negative optical power, the object side surface of the sixth lens at the optical axis is convex, the object side surface at the circumference is concave, the image side surface of the sixth lens at the optical axis is concave, the image side surface at the circumference is convex, and at least one inflection point is provided on at least one of the object side surface and the image side surface of the sixth lens; the optical system satisfies the conditional formula: -9 < f4 / |f1| < 3.5; where f1 is the effective focal length of the first lens and f4 is the effective focal length of the fourth lens. By reasonably configuring the surface types and optical powers of the first lens to the sixth lens, the requirements of good imaging, miniaturization, and large viewing angle are met. When the fourth lens provides a negative optical power, the viewing angle of the wide-angle lens can be further expanded. When the fourth lens provides a positive optical power, the total length of the wide-angle lens can be further shortened. By reasonably setting the value of f4 / |f1|, reasonably distributing the optical powers of the lenses, and configuring the lens shapes, it is beneficial to expand the viewing angle of the system.

[0007] In an embodiment, the optical system satisfies the conditional formula: 1.7 < tan(HFOV) / SD11 < 2.6; where HFOV is half of the maximum viewing angle of the optical system and SD11 is the effective semi-aperture of the object side surface of the first lens. By reasonably setting the value of tan(HFOV) / SD11, the optical lens exhibits the characteristics of a larger viewing angle and a short total length, maintaining the miniaturization of the system.

[0008] In an embodiment, the optical system satisfies the conditional formula: 0.7 < f2 / f5 < 1.5; where f2 is the effective focal length of the second lens and f5 is the effective focal length of the fifth lens. When f2 / f5 ≤ 0.7, the refractive power of the second lens is insufficient, resulting in difficulty in correcting the coma of the system; when f2 / f5 ≥ 1.5, due to the too strong refractive power of the second lens, the aberration correction of the rear lens group is excessive. Reasonably distributing the optical powers of the second lens and the fifth lens is beneficial to correcting the system aberration, especially reducing the coma of the system and balancing the spherical aberration generated by the negative lens of the system.

[0009] In an embodiment, the optical system satisfies the conditional formula: 0.5 < f1 / f6 < 1.5, where f1 is the effective focal length of the first lens and f6 is the effective focal length of the sixth lens. By reasonably distributing the effective focal lengths of the first lens and the sixth lens, the viewing angle can be further expanded, and the distortion can be effectively corrected.

[0010] In one embodiment, the optical system satisfies the conditional formula: 0.8 < CT2 / (T12 + T23) < 1.6; where CT2 is the thickness of the second lens on the optical axis, T12 is the distance between the first lens and the second lens on the optical axis, and T23 is the distance between the second lens and the third lens on the optical axis. By reasonably setting the value of CT2 / (T12 + T23), there is enough space for the three lenses during assembly, avoiding collisions between the first lens and the second lens or between the second lens and the third lens. In addition, the shortening of CT2, T12, and T23 is beneficial to the thinning of the wide-angle lens and can also prevent the value from being too small, which is not conducive to assembly and increases the sensitivity of the optical system. In one embodiment, the optical system satisfies the conditional formula: 0.5 < vd6 - vd3 < 4.5; where vd6 is the Abbe number of the sixth lens and vd3 is the Abbe number of the third lens. By reasonably selecting the lens materials, the chromatic aberration of the wide-angle lens can be effectively corrected, the imaging clarity of the optical lens can be improved, and thus the imaging quality of the wide-angle lens can be enhanced.

[0011] In one embodiment, the optical system satisfies the conditional formula: 1.2 < R12 / R13 < 2.5; where R12 is the curvature radius of the object side surface of the sixth lens and R13 is the curvature radius of the image side surface of the sixth lens. When R12 / R13 ≤ 1.2, the object side surface of the sixth lens will be overly curved, resulting in poor molding and affecting the manufacturing yield. When R12 / R13 ≥ 2.5, the surface shape of the sixth lens is too smooth, leading to difficulty in correcting aberrations and a relatively low relative brightness in the edge field of view, affecting the imaging quality of the wide-angle lens. By adjusting the curvature radius of the sixth lens, the processing feasibility of the sixth lens can be ensured, and spherical aberration and astigmatism can be effectively corrected, thereby enhancing the imaging quality of the camera.

[0012] In one embodiment, the optical system satisfies the conditional formula: CT5 / |SAG51| > 1; where CT5 is the thickness of the fifth lens on the optical axis and SAG51 is the horizontal displacement on the optical axis from the intersection of the object side surface of the fifth lens on the optical axis to the position of the maximum effective radius of the object side surface of the fifth lens. By reasonably setting the value of CT5 / |SAG51|, the shape of the lens is constrained within an appropriate range, which is beneficial to manufacturing and molding and reduces the defects of poor molding.

[0013] In one embodiment, the optical system satisfies the condition: 0.2<(CT1+CT3+CT4) / TTL<0.3; wherein CT1 is the center thickness of the first lens on the optical axis, CT3 is the center thickness of the third lens on the optical axis, CT4 is the center thickness of the fourth lens on the optical axis, and TTL is the distance from the object side of the first lens to the imaging surface of the optical system on the optical axis. Reasonable configuration of the thickness of the first lens, the third lens, and the fourth lens is conducive to reducing the sensitivity of the system while maintaining the miniaturization of the optical system.

[0014] In a second aspect, the present invention further provides a lens module, comprising a lens barrel and the optical system of the first aspect, wherein the first lens to the sixth lens of the optical system are installed in the lens barrel. By installing the first lens to the sixth lens of the optical system in the lens module, it is ensured that the lens module can meet the requirements of good imaging, miniaturization and wide viewing angle.

[0015] In a third aspect, the present invention further provides an electronic device, comprising a housing, an electronic photosensitive element and the lens module described in the second aspect, wherein the lens module and the electronic photosensitive element are arranged in the housing, and the electronic photosensitive element is arranged on the imaging surface of the optical system, and is used to convert the light of an object incident on the electronic photosensitive element through the first lens to the sixth lens into an electrical signal of an image. By installing the lens module described in the second aspect in the electronic device, the electronic device can be made thin and small, capable of shooting at a large angle and with excellent imaging quality. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0017] Figure 1a is a schematic structural diagram of the optical system of the first embodiment;

[0018] Figure 1b 7 are the longitudinal spherical aberration curve, astigmatism curve and distortion curve of the first embodiment;

[0019] Figure 2a is a schematic structural diagram of an optical system of a second embodiment;

[0020] Figure 2b 7 are the longitudinal spherical aberration curve, astigmatism curve and distortion curve of the second embodiment;

[0021] Figure 3ais a schematic structural diagram of an optical system of a third embodiment;

[0022] Figure 3b 7 are the longitudinal spherical aberration curve, astigmatism curve and distortion curve of the third embodiment;

[0023] Figure 4a is a schematic structural diagram of an optical system of a fourth embodiment;

[0024] Figure 4b 7 are the longitudinal spherical aberration curve, astigmatism curve and distortion curve of the fourth embodiment;

[0025] Figure 5a is a schematic structural diagram of an optical system of a fifth embodiment;

[0026] Figure 5b 7 are the longitudinal spherical aberration curve, astigmatism curve and distortion curve of the fifth embodiment;

[0027] Figure 6a is a schematic structural diagram of an optical system of a sixth embodiment;

[0028] Figure 6b 1 and 2 are the longitudinal spherical aberration curve, astigmatism curve, and distortion curve of the sixth embodiment. DETAILED DESCRIPTION

[0029] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0030] The embodiment of the present invention provides a lens module, including a lens barrel and an optical system provided by the embodiment of the present invention, wherein the first lens to the sixth lens of the optical system are installed in the lens barrel. The lens module can be an independent lens of a digital camera, or an imaging module integrated in an electronic device such as a smart phone. By installing the lenses of the optical system, the lens module has the characteristics of miniaturization and wide-angle shooting.

[0031] The embodiment of the present invention further provides an electronic device, including a housing, an electronic photosensitive element and a lens module provided by the embodiment of the present invention, the lens module and the electronic photosensitive element are arranged in the housing, and the electronic photosensitive element is arranged on the imaging surface of the optical system, and is used to convert the light of the object incident on the electronic photosensitive element through the first lens to the sixth lens into an electrical signal of an image. The electronic photosensitive element can be a complementary metal oxide semiconductor (CMOS) or a charge-coupled device (CCD). The electronic device can be a smart phone, a personal digital assistant (PDA), a tablet computer, a smart watch, a drone, an e-book reader, a driving recorder, a wearable device, etc. By setting the lens module of the present invention, the electronic device can be made thin and small, and can be used for shooting at a large angle.

[0032] The embodiment of the present invention provides an optical system including, for example, six lenses, namely, a first lens, a second lens, a third lens, a fourth lens, a fifth lens and a sixth lens, wherein the first lens to the sixth lens are sequentially arranged from the object side to the image side along the optical axis. Among the first lens to the sixth lens, any two adjacent lenses may have an air gap between them.

[0033] Specifically, the specific shape and structure of the six lenses are as follows:

[0034] The first lens has negative optical power; the second lens has positive optical power; the third lens has negative optical power; the fourth lens has optical power; the fifth lens has positive optical power, the object side surface of the fifth lens at the optical axis is convex, the object side surface at the circumference is concave, and the object side surface of the fifth lens is provided with at least one inflection point; the sixth lens has negative optical power, the object side surface of the sixth lens at the optical axis is convex, the object side surface at the circumference is concave, the image side surface of the sixth lens at the optical axis is concave, the image side surface at the circumference is convex, and at least one of the object side surface and the image side surface of the sixth lens is provided with at least one inflection point;

[0035] The optical system further includes an aperture, which can be arranged at any position between the first lens to the sixth lens, such as between the first lens and the second lens.

[0036] The optical system satisfies the following conditions:

[0037] -9 <f4 / |f1|<3.5;

[0038] Wherein, f1 is the effective focal length of the first lens, and f4 is the effective focal length of the fourth lens.

[0039] Reasonably set the surface shape and optical power of each of the first lens to the sixth lens to ensure that the optical system meets the requirements of miniaturization, good imaging, and large viewing angle. Meeting the above conditions simultaneously can reasonably distribute the optical power of the lenses and configure the lens shapes, which is beneficial to expanding the field of view angle of the system. When the fourth lens provides negative optical power, the field of view angle of the wide-angle lens can be further expanded; when the fourth lens provides positive optical power, the total length of the wide-angle lens can be further shortened.

[0040] In one embodiment, the optical system satisfies the conditional formula: 1.7 < tan(HFOV) / SD11 < 2.6; where HFOV is half of the maximum field of view angle of the optical system, and SD11 is the effective semi-aperture of the object side surface of the first lens. Reasonably configuring the ratio of tan(HFOV) / SD11 can make the optical lens exhibit the characteristics of a larger field of view angle and a short total length, and maintain the miniaturization of the system.

[0041] In one embodiment, the optical system satisfies the conditional formula: 0.7 < f2 / f5 < 1.5; where f2 is the effective focal length of the second lens, and f5 is the effective focal length of the fifth lens. When f2 / f5 ≤ 0.7, the refractive power of the second lens is insufficient, resulting in difficulty in correcting coma of the system; when f2 / f5 ≥ 1.5, due to the too strong refractive power of the second lens, overcorrection of the aberrations of the rear lens group occurs. Reasonably distributing the optical power of the second lens and the fifth lens is beneficial to correcting the system aberrations, especially reducing the coma of the system and balancing the spherical aberration generated by the negative lenses of the system.

[0042] In one embodiment, the optical system satisfies the conditional formula: 0.5 < f1 / f6 < 1.5, where f1 is the effective focal length of the first lens, and f6 is the effective focal length of the sixth lens. Reasonably configuring the ratio of the focal lengths of the first lens and the sixth lens, the wide-angle lens can further expand the field of view angle and effectively correct distortion.

[0043] In one embodiment, the optical system satisfies the conditional formula: 0.8 < CT2 / (T12 + T23) < 1.6; where CT2 is the thickness of the second lens on the optical axis, T12 is the distance between the first lens and the second lens on the optical axis, and T23 is the distance between the second lens and the third lens on the optical axis. Reasonably configuring the value of CT2 / (T12 + T23) can provide enough space for assembling the three lenses, avoiding collisions between the first lens and the second lens or between the second lens and the third lens. In addition, the shortening of CT2, T12, and T23 is beneficial to the thinning of the wide-angle lens, and can also avoid the value being too small and being unfavorable for assembly, increasing the sensitivity of the optical system.

[0044] In an embodiment, the optical system satisfies the conditional formula: 0.5 < vd6 - vd3 < 4.5; where vd6 is the Abbe number of the sixth lens and vd3 is the Abbe number of the third lens. By reasonably selecting the lens material, chromatic aberration of the wide-angle lens can be effectively corrected, the imaging clarity of the optical lens can be improved, and thus the imaging quality of the wide-angle lens can be enhanced.

[0045] In an embodiment, the optical system satisfies the conditional formula: 1.2 < R12 / R13 < 2.5; where R12 is the curvature radius of the object side surface of the sixth lens and R13 is the curvature radius of the image side surface of the sixth lens. By adjusting the curvature radius of the sixth lens, the processing feasibility of the sixth lens can be ensured, and at the same time, spherical aberration and astigmatism can be effectively corrected, improving the imaging quality of the camera. When R12 / R13 ≤ 1.2, the object side surface of the sixth lens will be overly curved, with poor forming, affecting the manufacturing yield. When R12 / R13 ≥ 2.5, the surface shape of the sixth lens is too smooth, resulting in difficulty in correcting aberrations and relatively low relative brightness in the edge field of view, affecting the imaging quality of the wide-angle lens.

[0046] In an embodiment, the optical system satisfies the conditional formula: CT5 / |SAG51| > 1; where CT5 is the thickness of the fifth lens on the optical axis and SAG51 is the horizontal displacement on the optical axis from the intersection of the object side surface of the fifth lens on the optical axis to the position of the maximum effective radius of the object side surface of the fifth lens. By reasonably configuring the value of CT5 / |SAG51|, the lens shape is appropriate, which is beneficial to manufacturing and forming, and reduces the defects of poor forming.

[0047] In an embodiment, the optical system satisfies the conditional formula: 0.2 < (CT1 + CT3 + CT4) / TTL < 0.3; where CT1 is the central thickness of the first lens on the optical axis, CT3 is the central thickness of the third lens on the optical axis, CT4 is the central thickness of the fourth lens on the optical axis, 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. By configuring the thicknesses of the first lens, the third lens, and the fourth lens, it is beneficial to reduce the sensitivity of the system while maintaining the miniaturization of the optical system.

[0048] First Embodiment

[0049] Please refer to Figure 1a and Figure 1b , the optical system of this embodiment sequentially includes, from the object side to the image side along the optical axis direction:

[0050] The first lens L1, having a negative optical power, the object side surface S1 of the first lens L1 is convex, and the image side surface S2 of the first lens L1 is concave;

[0051] The second lens L2, having a positive optical power, the object side surface S3 of the second lens L2 is convex, and the image side surface S4 of the second lens L2 is convex;

[0052] The third lens L3 has negative power. The object-side surface S5 of the third lens L3 at the optical axis is convex, and the object-side surface S5 at the circumference is concave. The image-side surface S6 of the third lens L3 at the optical axis is concave, and the image-side surface S6 at the circumference is convex.

[0053] The fourth lens L4 has negative power. The object-side surface S7 of the third lens L3 at the optical axis is convex, and the object-side surface S7 at the circumference is concave. The image-side surface S8 of the third lens L3 at the optical axis is concave, and the image-side surface S8 at the circumference is convex.

[0054] The fifth lens L5 has positive refractive power. The object-side surface S9 of the fifth lens L5 at the optical axis is convex, and the object-side surface S9 at the circumference is concave. The image-side surface S10 of the fifth lens L5 is convex.

[0055] The sixth lens L6 has negative power. The object-side surface S11 of the sixth lens L5 at the optical axis is convex, and the object-side surface S11 at the circumference is concave. The image-side surface S12 of the sixth lens L5 at the optical axis is concave, and the image-side surface S12 at the circumference is convex.

[0056] The materials of the first lens L1 to the sixth lens L6 are all plastic.

[0057] In addition, the optical system also includes an aperture STO, an infrared cutoff filter L7 and an imaging surface S13. The aperture STO is arranged between the first lens L1 and the second lens L2, and is adjacent to the second lens L2, for controlling the amount of light entering. In other embodiments, the aperture STO can also be arranged between other adjacent lenses. The infrared cutoff filter L7 is arranged on the image side of the sixth lens L6, and includes an object side surface S13 and an image side surface S14. The infrared cutoff filter L7 is used to filter out infrared light, so that the light incident on the imaging surface S15 is visible light, and the wavelength of visible light is 380nm-780nm. The material of the infrared cutoff filter L7 is glass (Glass), and a film can be coated on the glass. The imaging surface S15 is an effective pixel area of ​​the electronic photosensitive element.

[0058] Table 1a shows a table of characteristics of the optical system of this embodiment, wherein the data are obtained using light with a wavelength of 587.6 nm, and the units of Y radius, thickness and focal length are all millimeters (mm).

[0059] Table 1a

[0060]

[0061]

[0062] Wherein, EFL is the effective focal length of the optical system, FNO is the aperture number of the optical system, FOV is the field of view of the optical system, and TTL is the distance from the object side of the first lens to the imaging plane of the optical system on the optical axis.

[0063] In this embodiment, the object side surface and the image side surface of any lens of the first lens L1 to the sixth lens L6 are both aspherical surfaces, and the surface shape x of each aspherical lens can be defined by but not limited to the following aspherical surface formula:

[0064]

[0065] Wherein, x is the distance vector height from the vertex of the aspherical surface when the aspherical surface is at a height of h along the optical axis; c is the paraxial curvature of the aspherical surface, c=1 / R (i.e., the paraxial curvature c is the reciprocal of the Y radius R in the above Table 1a); k is the cone coefficient; Ai is the correction coefficient of the i-th order of the aspherical surface. Table 1b shows the high-order coefficients A4, A6, A8, A10, A12, A14, A16, A18 and A20 that can be used for each aspherical mirror surface S1-S10 in the first embodiment.

[0066] Table 1b

[0067]

[0068]

[0069] Figure 1b The longitudinal spherical aberration curve, astigmatism curve and distortion curve of the optical system of the first embodiment are shown. The longitudinal spherical aberration curve indicates the deviation of the focal point of light of different wavelengths after passing through each lens of the optical system; the astigmatism curve indicates the meridional image curvature and sagittal image curvature; and the distortion curve indicates the distortion magnitude value corresponding to different field angles. Figure 1b It can be seen that the optical system provided in the first embodiment can achieve good imaging quality.

[0070] Second embodiment

[0071] Please refer to Figure 2a and Figure 2b The optical system of this embodiment includes, in order from the object side to the image side along the optical axis:

[0072] The first lens L1 has negative optical power, the object-side surface S1 of the first lens L1 is convex, and the image-side surface S2 of the first lens L1 is concave;

[0073] The second lens L2 has positive refractive power, the object-side surface S3 of the second lens L2 is convex, and the image-side surface S4 of the second lens L2 is convex;

[0074] The third lens L3 has negative power. The object side surface S5 of the third lens L3 is concave. The image side surface S6 of the third lens L3 at the optical axis is concave, and the image side surface S6 at the circumference is convex.

[0075] The fourth lens L4 has negative optical power. The object-side surface S7 of the third lens L3 is convex. The image-side surface S8 of the third lens L3 at the optical axis is concave, and the image-side surface S8 at the circumference is convex.

[0076] The fifth lens L5 has positive refractive power. The object-side surface S9 of the fifth lens L5 at the optical axis is convex, and the object-side surface S9 at the circumference is concave. The image-side surface S10 of the fifth lens L5 is convex.

[0077] The sixth lens L6 has negative power. The object-side surface S11 of the sixth lens L5 at the optical axis is convex, and the object-side surface S11 at the circumference is concave. The image-side surface S12 of the sixth lens L5 at the optical axis is concave, and the image-side surface S12 at the circumference is convex.

[0078] The other structures of the second embodiment are the same as those of the first embodiment, and can be used as a reference.

[0079] Table 2a shows a table of the characteristics of the optical system of this embodiment, wherein the data are obtained using light with a wavelength of 587.6 nm, and the units of the Y radius, thickness and focal length are all millimeters (mm).

[0080] Table 2a

[0081]

[0082] The meanings of the parameters in Table 2a are the same as those in the first embodiment.

[0083] Table 2b gives the coefficients of the higher-order terms that can be used for each aspherical mirror surface in the second embodiment, wherein each aspherical surface shape can be defined by the formula given in the first embodiment.

[0084] Table 2b

[0085]

[0086]

[0087] Figure 2b The longitudinal spherical aberration curve, astigmatism curve and distortion curve of the optical system of the second embodiment are shown. The longitudinal spherical aberration curve indicates the deviation of the convergence point of light of different wavelengths after passing through each lens of the optical system; the astigmatism curve indicates the meridional image curvature and sagittal image curvature; and the distortion curve indicates the distortion magnitude value corresponding to different field angles. Figure 2b It can be seen that the optical system provided in the second embodiment can achieve good imaging quality.

[0088] Third embodiment

[0089] Please refer to Figure 3a and Figure 3b The optical system of this embodiment includes, in order from the object side to the image side along the optical axis:

[0090] The first lens L1 has negative optical power, the object-side surface S1 of the first lens L1 is convex, and the image-side surface S2 of the first lens L1 is concave;

[0091] The second lens L2 has positive refractive power, the object-side surface S3 of the second lens L2 is convex, and the image-side surface S4 of the second lens L2 is convex;

[0092] The third lens L3 has negative power. The object side surface S5 of the third lens L3 is concave. The image side surface S6 of the third lens L3 at the optical axis is concave, and the image side surface S6 at the circumference is convex.

[0093] The fourth lens L4 has positive refractive power. The object-side surface S7 of the third lens L3 at the optical axis is convex, and the object-side surface S7 at the circumference is concave. The image-side surface S8 of the third lens L3 at the optical axis is concave, and the image-side surface S8 at the circumference is convex.

[0094] The fifth lens L5 has positive refractive power. The object-side surface S9 of the fifth lens L5 at the optical axis is convex, and the object-side surface S9 at the circumference is concave. The image-side surface S10 of the fifth lens L5 is convex.

[0095] The sixth lens L6 has negative power. The object-side surface S11 of the sixth lens L5 at the optical axis is convex, and the object-side surface S11 at the circumference is concave. The image-side surface S12 of the sixth lens L5 at the optical axis is concave, and the image-side surface S12 at the circumference is convex.

[0096] The other structures of the third embodiment are the same as those of the first embodiment, and can be used as a reference.

[0097] Table 3a shows a table of the characteristics of the optical system of this embodiment, wherein the data are obtained using light with a wavelength of 587.6 nm, and the units of the Y radius, thickness and focal length are all millimeters (mm).

[0098] Table 3a

[0099]

[0100] The meanings of the parameters in Table 3a are the same as those in the first embodiment.

[0101] Table 3b gives the coefficients of the higher-order terms that can be used for each aspherical mirror surface in the third embodiment, wherein each aspherical surface shape can be defined by the formula given in the first embodiment.

[0102] Table 3b

[0103]

[0104]

[0105] Figure 3b The longitudinal spherical aberration curve, astigmatism curve and distortion curve of the optical system of the third embodiment are shown. The longitudinal spherical aberration curve indicates the deviation of the focal point of light of different wavelengths after passing through each lens of the optical system; the astigmatism curve indicates the meridional image curvature and sagittal image curvature; and the distortion curve indicates the distortion magnitude value corresponding to different field angles. Figure 3b It can be seen that the optical system provided in the third embodiment can achieve good imaging quality.

[0106] Fourth embodiment

[0107] Please refer to Figure 4a and Figure 4b The optical system of this embodiment includes, in order from the object side to the image side along the optical axis:

[0108] The first lens L1 has negative optical power, the object-side surface S1 of the first lens L1 is convex, and the image-side surface S2 of the first lens L1 is concave;

[0109] The second lens L2 has positive refractive power, the object-side surface S3 of the second lens L2 at the optical axis is convex, the object-side surface S3 at the circumference is concave, and the image-side surface S4 of the second lens L2 is convex;

[0110] The third lens L3 has negative optical power, the object-side surface S5 of the third lens L3 at the optical axis is convex, the object-side surface S5 at the circumference is concave, and the image-side surface S6 of the third lens L3 is concave;

[0111] The fourth lens L4 has negative optical power. The object-side surface S7 of the third lens L3 is convex. The image-side surface S8 of the third lens L3 at the optical axis is concave, and the image-side surface S8 at the circumference is convex.

[0112] The fifth lens L5 has positive refractive power. The object-side surface S9 of the fifth lens L5 at the optical axis is convex, and the object-side surface S9 at the circumference is concave. The image-side surface S10 of the fifth lens L5 is convex.

[0113] The sixth lens L6 has negative power. The object-side surface S11 of the sixth lens L5 at the optical axis is convex, and the object-side surface S11 at the circumference is concave. The image-side surface S12 of the sixth lens L5 at the optical axis is concave, and the image-side surface S12 at the circumference is convex.

[0114] The other structures of the fourth embodiment are the same as those of the first embodiment, and can be referred to herein.

[0115] Table 4a shows a table of the characteristics of the optical system of this embodiment, wherein the data are obtained using light with a wavelength of 587.6 nm, and the units of Y radius, thickness and focal length are all millimeters (mm).

[0116] Table 4a

[0117]

[0118] The meanings of the parameters in Table 4a are the same as those in the first embodiment.

[0119] Table 4b gives the coefficients of the higher-order terms that can be used for each aspherical mirror surface in the fourth embodiment, wherein each aspherical surface shape can be defined by the formula given in the first embodiment.

[0120] Table 4b

[0121]

[0122]

[0123] Figure 4b The longitudinal spherical aberration curve, astigmatism curve and distortion curve of the optical system of the fourth embodiment are shown. The longitudinal spherical aberration curve indicates the deviation of the convergence point of light of different wavelengths after passing through each lens of the optical system; the astigmatism curve indicates the meridional image curvature and sagittal image curvature; and the distortion curve indicates the distortion magnitude value corresponding to different field angles. Figure 4b It can be seen that the optical system provided in the fourth embodiment can achieve good imaging quality.

[0124] Fifth embodiment

[0125] Please refer to Figure 5a and Figure 5b The optical system of this embodiment includes, in order from the object side to the image side along the optical axis:

[0126] The first lens L1 has negative refractive power, the object side surface S1 of the first lens L1 at the optical axis is concave, the object side surface S1 at the circumference is convex, and the image side surface S2 of the first lens L1 is concave;

[0127] The second lens L2 has positive refractive power, the object-side surface S3 of the second lens L2 is convex, and the image-side surface S4 of the second lens L2 is convex;

[0128] The third lens L3 has negative optical power, the object-side surface S5 of the third lens L3 at the optical axis is convex, the object-side surface S5 at the circumference is concave, and the image-side surface S6 of the third lens L3 is concave;

[0129] The fourth lens L4 has negative optical power. The object-side surface S7 of the third lens L3 is convex. The image-side surface S8 of the third lens L3 at the optical axis is concave, and the image-side surface S8 at the circumference is convex.

[0130] The fifth lens L5 has positive refractive power. The object-side surface S9 of the fifth lens L5 at the optical axis is convex, and the object-side surface S9 at the circumference is concave. The image-side surface S10 of the fifth lens L5 is convex.

[0131] The sixth lens L6 has negative power. The object-side surface S11 of the sixth lens L5 at the optical axis is convex, and the object-side surface S11 at the circumference is concave. The image-side surface S12 of the sixth lens L5 at the optical axis is concave, and the image-side surface S12 at the circumference is convex.

[0132] The other structures of the fifth embodiment are the same as those of the first embodiment, and can be referred to herein.

[0133] Table 5a shows a table of the characteristics of the optical system of this embodiment, wherein the data are obtained using light with a wavelength of 597.6 nm, and the units of Y radius, thickness and focal length are all millimeters (mm).

[0134] Table 5a

[0135]

[0136] The meanings of the parameters in Table 5a are the same as those in the first embodiment.

[0137] Table 5b gives the coefficients of the higher-order terms that can be used for each aspherical mirror surface in the fifth embodiment, wherein each aspherical surface shape can be defined by the formula given in the first embodiment.

[0138]

[0139]

[0140] Figure 5b The longitudinal spherical aberration curve, astigmatism curve and distortion curve of the optical system of the fifth embodiment are shown. The longitudinal spherical aberration curve indicates the deviation of the convergence point of light of different wavelengths after passing through each lens of the optical system; the astigmatism curve indicates the meridional image curvature and sagittal image curvature; and the distortion curve indicates the distortion magnitude value corresponding to different field angles. Figure 5b It can be seen that the optical system provided in the fifth embodiment can achieve good imaging quality.

[0141] Sixth embodiment

[0142] Please refer to Figure 6a and Figure 6b The optical system of this embodiment includes, in order from the object side to the image side along the optical axis:

[0143] The first lens L1 has negative refractive power, the object side surface S1 of the first lens L1 at the optical axis is concave, the object side surface S1 at the circumference is convex, and the image side surface S2 of the first lens L1 is concave;

[0144] The second lens L2 has positive refractive power, the object-side surface S3 of the second lens L2 is convex, and the image-side surface S4 of the second lens L2 is convex;

[0145] The third lens L3 has negative power. The object-side surface S5 of the third lens L3 at the optical axis is convex, and the object-side surface S5 at the circumference is concave. The image-side surface S6 of the third lens L3 at the optical axis is concave, and the image-side surface S6 at the circumference is convex.

[0146] The fourth lens L4 has positive refractive power. The object-side surface S7 of the third lens L3 at the optical axis is convex, the object-side surface S7 at the circumference is concave, and the image-side surface S8 of the third lens L3 is convex.

[0147] The fifth lens L5 has positive refractive power. The object-side surface S9 of the fifth lens L5 at the optical axis is convex, and the object-side surface S9 at the circumference is concave. The image-side surface S10 of the fifth lens L5 is convex.

[0148] The sixth lens L6 has negative power. The object-side surface S11 of the sixth lens L5 at the optical axis is convex, and the object-side surface S11 at the circumference is concave. The image-side surface S12 of the sixth lens L5 at the optical axis is concave, and the image-side surface S12 at the circumference is convex.

[0149] The other structures of the sixth embodiment are the same as those of the first embodiment, and can be referred to herein.

[0150] Table 6a shows a table of the characteristics of the optical system of this embodiment, wherein the data is obtained using light with a wavelength of 597.6 nm, and the units of Y radius, thickness and focal length are all millimeters (mm).

[0151] Table 6a

[0152]

[0153]

[0154] The meanings of the parameters in Table 6a are the same as those in the first embodiment.

[0155] Table 6b gives the coefficients of the higher-order terms that can be used for each aspherical mirror surface in the sixth embodiment, wherein each aspherical surface shape can be defined by the formula given in the first embodiment.

[0156] Table 6b

[0157]

[0158]

[0159] Figure 6b The longitudinal spherical aberration curve, astigmatism curve and distortion curve of the optical system of the sixth embodiment are shown. The longitudinal spherical aberration curve indicates the deviation of the convergence point of light of different wavelengths after passing through each lens of the optical system; the astigmatism curve indicates the meridional image curvature and sagittal image curvature; and the distortion curve indicates the distortion magnitude value corresponding to different field angles. Figure 6b It can be seen that the optical system provided in the sixth embodiment can achieve good imaging quality.

[0160] Table 7 shows the values ​​of f4 / |f1|, tan(HFOV) / SD11, f2 / f5, f1 / f6, CT2 / (T12+T23), vd6-vd3, R12 / R13, CT5 / |SAG51| and (CT1+CT3+CT4) / TTL of the optical systems of the first to sixth embodiments. It can be concluded from Table 7 that each embodiment satisfies: <f4 / |f1|<3.5、1.7<tan(HFOV) / SD11<2.6、0.7<f2 / f5<1.5、0.5<f1 / f6<1.5、0.8<CT2 / (T12+T23)<1.6、0.5<vd6-vd3<4.5、1.2<R12 / R13<2.5、CT5 / |SAG51|> 1, and 0.2<(CT1+CT3+CT4) / TTL<0.3.

[0161] Table 7

[0162] -9<f4 / |f1|<3.5 1.7<tan(HFOV) / SD11<2.6 0.7<f2 / f5<1.5 First embodiment -1.793 2.247 1.426 Second embodiment -4.594 1.807 1.076 Third embodiment 3.17 2.507 0.952 Fourth embodiment -8.123 2.34 1.029 Fifth embodiment -7.308 2.327 0.831 Sixth embodiment 1.958 2.39 0.842 0.5<f1 / f6<1.5 0.8<CT2 / (T12+T23)<1.6 0.5<vd6-vd3<4.5 First embodiment 1.380 0.92 3.6 Second embodiment 0.764 1.04 1.74 Third embodiment 1.148 1.02 2.89 Fourth embodiment 0.828 1 1.15 Fifth embodiment 0.584 1.59 1.15 Sixth embodiment 0.767 0.94 2.89 1.2<R12 / R13<2.5 CT5 / |SAG51|>1 0.2<(CT1+CT3+CT4) / TTL<0.3 First embodiment 2.20 4.28 0.226 Second embodiment 1.66 31.00 0.248 Third embodiment 2.04 1.82 0.245 Fourth embodiment 1.55 11.38 0.207 Fifth embodiment 1.50 60.90 0.241 Sixth embodiment 1.70 0.85 0.273

[0163] What is disclosed above is only a preferred embodiment of the present invention, and it certainly cannot be used to limit the scope of rights of the present invention. Ordinary technicians in this field can understand that all or part of the processes of implementing the above-mentioned embodiment and making equivalent changes according to the claims of the present invention still fall within the scope of the invention.

Claims

1. An optical system, characterized in that: It consists of six lenses, including: A first lens having negative optical power; The second lens has positive power; A third lens having negative optical power; a fourth lens having optical power; a fifth lens having positive power, wherein the object side surface of the fifth lens at the optical axis is convex, the object side surface at the circumference is concave, and the object side surface of the fifth lens is provided with at least one inflection point; a sixth lens having negative optical power, wherein the object side surface of the sixth lens at the optical axis is convex, and the object side surface at the circumference is concave, the image side surface of the sixth lens at the optical axis is concave, and the image side surface at the circumference is convex, and at least one of the object side surface and the image side surface of the sixth lens is provided with at least one inflection point; The optical system satisfies the condition: -9 <f4 / |f1|<3.5,0.7<f2 / f5<1.5,0.5<f1 / f6<1.5; Among them, f1 is the effective focal length of the first lens, f2 is the effective focal length of the second lens, f4 is the effective focal length of the fourth lens, f5 is the effective focal length of the fifth lens, and f6 is the effective focal length of the sixth lens.

2. The optical system according to claim 1, wherein: The optical system satisfies the condition: 1.7 <tan(HFOV) / SD11<2.6; Wherein, HFOV is half of the maximum field of view of the optical system, and SD11 is the effective semi-aperture of the object side of the first lens.

3. The optical system according to claim 1, wherein: The optical system satisfies the condition: 0.8 <CT2 / (T12+T23)<1.6; Wherein, CT2 is the thickness of the second lens on the optical axis, T12 is the distance between the first lens and the second lens on the optical axis, and T23 is the distance between the second lens and the third lens on the optical axis.

4. The optical system according to claim 1, wherein: The optical system satisfies the condition: 0.5 <vd6-vd3<4.5; Wherein, vd6 is the Abbe number of the sixth lens, and vd3 is the Abbe number of the third lens.

5. The optical system according to claim 1, wherein: The optical system satisfies the condition: 1.2 <R12 / R13<2.5; Among them, R12 is the curvature radius of the object side surface of the sixth lens, and R13 is the curvature radius of the image side surface of the sixth lens.

6. The optical system according to claim 1, wherein: The optical system satisfies the condition: CT5 / |SAG51|>1; Among them, CT5 is the thickness of the fifth lens on the optical axis, and SAG51 is the horizontal displacement of the intersection of the object side surface of the fifth lens on the optical axis to the maximum effective radius position of the object side surface of the fifth lens on the optical axis.

7. The optical system according to claim 1, wherein: The optical system satisfies the condition: 0.2<(CT1+CT3+CT4) / TTL<0.3; Among them, CT1 is the center thickness of the first lens on the optical axis, CT3 is the center thickness of the third lens on the optical axis, CT4 is the center thickness of the fourth lens on the optical axis, and TTL is the distance from the object side of the first lens to the imaging surface of the optical system on the optical axis.

8. A lens module, characterized in that: The optical system comprises a lens barrel and the optical system as claimed in any one of claims 1 to 7, wherein the first lens to the sixth lens of the optical system are installed in the lens barrel.

9. An electronic device, characterized in that: It includes a shell, an electronic photosensitive element and a lens module as described in claim 8, wherein the lens module and the electronic photosensitive element are arranged in the shell, and the electronic photosensitive element is arranged on the imaging surface of the optical system, and is used to convert the light of the object that passes through the first lens to the sixth lens and is incident on the electronic photosensitive element into an electrical signal of an image.

Images