Optical systems, lens modules and electronic equipment

Abstract

The present invention provides an optical system, a lens module and an electronic device. The optical system includes, from the object side to the image side along the optical axis direction: a first lens having positive refractive power, a convex object side surface and a concave image side surface at the near optical axis; a second lens having refractive power, a convex object side surface at the near optical axis and a concave image side surface at the near optical axis; a third lens having refractive power; a fourth lens having positive refractive power; a fifth lens having refractive power; a sixth lens having negative refractive power, a concave image side surface at the near optical axis and a convex surface at the near circumference, 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 object side surface and the image side surface of the third, fourth and fifth lenses are all aspherical surfaces. By reasonably configuring the surface shape and refractive power of each lens from the first to the sixth, the optical system has a higher imaging quality, is adapted to electronic photosensitive chips with higher pixels, and is miniaturized.

Description

Technical Field

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

[0002] As the market demands for high-quality video, telephoto lenses have emerged. Currently, conventional telephoto lenses have a long physical focal length in their optical systems and support low-pixel photosensitive chips, which are difficult to meet market demand.

[0003] Therefore, it is necessary to further improve the imaging quality of the optical system of the telephoto lens, and at the same time adapt it to electronic photosensitive chips with higher pixels. Moreover, on this basis, the physical length of the optical system should be reduced as much as possible to achieve the miniaturization of the telephoto lens. Summary of the invention

[0004] The object of the present invention is to provide an optical system, a lens module and an electronic device, which can have higher imaging quality, can be adapted to electronic photosensitive chips with higher pixels, and can meet the requirements of miniaturization.

[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 comprises, in order from the object side to the image side along the optical axis direction: a first lens having positive refractive power, the object side surface of the first lens being convex, and the image side surface of the first lens being concave near the optical axis; a second lens having refractive power, the object side surface of the second lens being convex near the optical axis, and the image side surface of the second lens being concave near the optical axis; a third lens having refractive power, the object side surface and the image side surface of the third lens being aspherical surfaces; a fourth lens having positive refractive power, the object side surface and the image side surface of the fourth lens being aspherical surfaces; a fifth lens having refractive power, the object side surface and the image side surface of the fifth lens being aspherical surfaces; a sixth lens having negative refractive power, the image side surface of the sixth lens being concave near the optical axis, the image side surface of the sixth lens being convex near the circumference, and at least one of the object side surface and the image side surface of the sixth lens being provided with at least one inflection point. By rationally configuring the surface shape and refractive power of each lens from the first lens to the sixth lens, the optical system described in the present application can have higher imaging quality, while being compatible with electronic photosensitive chips with higher pixels and meeting the requirements of miniaturization.

[0007] In one embodiment, the optical system satisfies the conditional formula: 45.5≤f*43 / ImgH<61.0; wherein f is the effective focal length of the optical system, and ImgH is the diagonal length of the effective imaging area of ​​the optical system on the imaging plane. By reasonably setting the value of f*43 / ImgH, the optical system of the present application can have better telephoto capability, can adapt to larger size and higher pixel electronic photosensitive chips, and better enable distant objects to obtain close-up imaging effects.

[0008] In one embodiment, the optical system satisfies the condition: 0.89≤TTL / f<1.0; wherein TTL is the distance from the object side of the first lens to the imaging surface of the optical system on the optical axis, and f is the effective focal length of the optical system. By reasonably setting the value of TTL / f, the optical system of the present application can provide a higher effective focal length within a certain range, reduce the physical length TTL of the optical system, and make it easier to be implanted in portable devices.

[0009] In one embodiment, the optical system satisfies the condition: 5.5° / mm<FOV / f<8.2° / mm; wherein FOV is the diagonal field of view of the optical system, and f is the effective focal length of the optical system. By reasonably setting the value of FOV / f, the optical system of the present application can obtain a larger field of view FOV at a certain effective focal length, thereby increasing the imaging range of the telephoto lens for distant objects.

[0010] In one embodiment, the optical system satisfies the conditional formula: 1.9<(|R32|+|R42|) / f≤13.44; wherein R32 is the radius of curvature of the image side surface of the third lens at the optical axis, R42 is the radius of curvature of the image side surface of the fourth lens at the optical axis, and f is the effective focal length of the optical system. By reasonably setting the value of (|R32|+|R42|) / f, most of the distortion and coma generated by the front lens can be offset, while the introduction of large spherical aberration and vertical axis chromatic aberration can be effectively avoided, thereby facilitating the reasonable distribution of primary aberrations on each lens and reducing tolerance sensitivity.

[0011] In one embodiment, the optical system satisfies the conditional formula: 3.3≤R51 / CT56<28.7; wherein R51 is the radius of curvature of the object side of the fifth lens at the optical axis, and CT56 is the distance between the image side of the fifth lens and the object side of the sixth lens on the optical axis. By reasonably setting the value of R51 / CT56, the difficulty of molding and assembling the optical system can be effectively reduced.

[0012] In one embodiment, the optical system satisfies the condition: 1.2<(CT1+CT2+CT3) / BF<2.1; wherein CT1 is the thickness of the first lens on the optical axis, CT2 is the thickness of the second lens on the optical axis, CT3 is the thickness of the third lens on the optical axis, and BF is the distance from the image side of the sixth lens to the closest imaging surface along the optical axis. By reasonably setting the value of (CT1+CT2+CT3) / BF, the aberrations generated by the first lens, the second lens, and the third lens are small, thereby reducing the difficulty of balancing the aberrations of the optical system.

[0013] In one embodiment, the optical system satisfies the conditional formula: 1.0<SAG61 / CT6<2.9; wherein SAG61 is the axial distance between the intersection of the object side of the sixth lens and the optical axis and the farthest point of the surface along the optical axis to the imaging surface, and CT6 is the thickness of the sixth lens on the optical axis. By reasonably setting the value of SAG61 / CT6, a good deflection angle is provided for the deflection of light at the edge of the lens, avoiding aberrations that are difficult to correct due to excessive deflection, and at the same time reducing the difficulty of lens molding, thereby improving production yield.

[0014] In one embodiment, the optical system satisfies the condition:

[0015] 19<(|f3|+f4+|f5|) / (CT34+CT45+CT56)<103; wherein, f3 is the effective focal length of the third lens, f4 is the effective focal length of the fourth lens, f5 is the effective focal length of the fifth lens, CT34 is the distance between the image side surface of the third lens and the object side surface of the fourth lens on the optical axis, CT45 is the distance between the image side surface of the fourth lens and the object side surface of the fifth lens on the optical axis, and CT56 is the distance between the image side surface of the fifth lens and the object side surface of the sixth lens on the optical axis. By reasonably setting the value of (|f3|+f4+|f5|) / (CT34+CT45+CT56), the spherical aberration, chromatic aberration, etc. generated by the front lens group can be effectively balanced, thereby improving the overall image quality.

[0016] In one embodiment, the optical system satisfies the condition: 2.7mm<TTL / FNO<3.1mm; wherein TTL is the distance from the object side of the first lens to the imaging surface of the optical system on the optical axis, and FNO is the aperture number of the optical system. By properly setting the value of TTL / FNO, the optical system can have a large aperture effect, and the detail effect of the optical system in telephoto shooting can be improved to a certain extent.

[0017] In a second aspect, the present invention further provides a lens module, the lens module comprising a lens barrel and the optical system in any one of the embodiments of the first aspect, the first lens to the sixth lens of the optical system are installed in the lens barrel, and the electronic photosensitive chip is arranged on the image side 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 chip into an electrical signal of the image. By installing the first lens to the sixth lens of the optical system in the lens module, the lens module of the present application has a higher imaging quality and can be adapted to an electronic photosensitive chip with a higher pixel, and the overall length of the lens module is short, so that miniaturization is achieved.

[0018] In a third aspect, the present invention further provides an electronic device, the electronic device comprising a housing and the lens module of the second aspect, wherein the lens module is arranged in the housing. By arranging the lens module of the second aspect in the electronic device, the electronic device has a higher image quality, and the overall length of the electronic device is shorter, thereby achieving miniaturization. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] 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.

[0020] Figure 1a is a schematic structural diagram of the optical system of the first embodiment;

[0021] Figure 1b 7 are the longitudinal spherical aberration curve, astigmatism curve and distortion curve of the first embodiment;

[0022] Figure 2a is a schematic structural diagram of an optical system of a second embodiment;

[0023] Figure 2b 7 are the longitudinal spherical aberration curve, astigmatism curve and distortion curve of the second embodiment;

[0024] Figure 3a is a schematic structural diagram of an optical system of a third embodiment;

[0025] Figure 3b 7 are the longitudinal spherical aberration curve, astigmatism curve and distortion curve of the third embodiment;

[0026] Figure 4a is a schematic structural diagram of an optical system of a fourth embodiment;

[0027] Figure 4b7 are the longitudinal spherical aberration curve, astigmatism curve and distortion curve of the fourth embodiment;

[0028] Figure 5a is a schematic structural diagram of an optical system of a fifth embodiment;

[0029] Figure 5b 7 are the longitudinal spherical aberration curve, astigmatism curve and distortion curve of the fifth embodiment;

[0030] Figure 6a is a schematic structural diagram of an optical system of a sixth embodiment;

[0031] Figure 6b 1 and 2 are the longitudinal spherical aberration curve, astigmatism curve, and distortion curve of the sixth embodiment.

[0032] Figure 7a is a schematic structural diagram of an optical system of a seventh embodiment;

[0033] Figure 7b 7 are the longitudinal spherical aberration curve, astigmatism curve and distortion curve of the seventh embodiment; DETAILED DESCRIPTION

[0034] 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.

[0035] The embodiment of the present invention provides a lens module, which includes a lens barrel, an electronic photosensitive chip 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, and the electronic photosensitive chip is arranged on the image side of the optical system, and is used to convert the light of the object incident on the electronic photosensitive chip through the first lens to the sixth lens into an electrical signal of an image. The electronic photosensitive chip can be a complementary metal oxide semiconductor (CMOS). 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 first lens to the sixth lens of the optical system in the lens module, the lens module provided by the embodiment of the present application has a higher imaging quality, and can be adapted to an electronic photosensitive chip with a higher pixel, and the overall length of the lens module is small, so as to achieve miniaturization.

[0036] An embodiment of the present invention provides an electronic device, which includes a housing and a lens module provided by an embodiment of the present invention. The lens module and the electronic photosensitive chip are arranged in the housing. 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 second aspect in the electronic device, the electronic device provided by the embodiment of the present application has a higher imaging quality, and the overall length of the electronic device is small, thereby achieving miniaturization.

[0037] An embodiment of the present invention provides an optical system, which includes a first lens, a second lens, a third lens, a fourth lens, a fifth lens and a sixth lens in order 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.

[0038] Specifically, the specific shapes and structures of the six lenses are as follows: the first lens has positive refractive power, the object side surface of the first lens is convex, and the image side surface of the first lens is concave near the optical axis; the second lens has refractive power, 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 third lens has refractive power, and the object side surface and image side surface of the third lens are both aspherical surfaces; the fourth lens has positive refractive power, and the object side surface and image side surface of the fourth lens are both aspherical surfaces; the fifth lens has refractive power, and the object side surface and image side surface of the fifth lens are both aspherical surfaces; the sixth lens has negative refractive power, the image side surface of the sixth lens is concave near the optical axis, and the image side surface of the sixth lens is convex near the circumference, 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 also includes an aperture, which can be set at any position between the first lens to the sixth lens, such as being set on the first lens.

[0039] In one embodiment, the optical system satisfies the conditional formula: 45.5≤f*43 / ImgH<61.0; wherein f is the effective focal length of the optical system, and ImgH is the diagonal length of the effective imaging area of ​​the optical system on the imaging plane. This conditional formula is the equivalent focal length of the optical system calculated based on the full frame. Generally, the equivalent focal length of the optical system is greater than 50mm, that is, it has a certain telephoto capability. When the optical system satisfies the above conditional formula, it means that the lens composed of the optical system provided in the embodiment of the present application has a magnification capability of more than 2 times that of a 25mm imaging lens. It should be noted that if ImgH is larger, the optical system can be adapted to electronic photosensitive chips of larger size and higher pixel. At the same time, reasonable lens size and refractive power configuration can allow distant objects to obtain close-up imaging effects.

[0040] In one embodiment, the optical system satisfies the conditional formula: 0.89≤TTL / f<1.0; wherein TTL is the distance from the object side of the first lens to the imaging surface of the optical system on the optical axis, and f is the effective focal length of the optical system. In a specific embodiment, f is greater than 6 mm, so the optical system can have a certain telephoto capability when combined with an electronic photosensitive chip of a certain size. When the optical system satisfies the above conditional formula, within the range of TTL<6.5 mm, the optical system can provide a higher effective focal length, reduce the physical length TTL of the optical system, and make the optical system easier to implant in portable devices. It should be noted that in the optical system, the use of aspheric lenses makes TTL less than the effective focal length f, which is beneficial for the optical system to balance aberrations such as chromatic aberration, spherical aberration and distortion, thereby obtaining good imaging quality.

[0041] In one embodiment, the optical system satisfies the conditional formula: 5.5° / mm<FOV / f<8.2° / mm; wherein FOV is the diagonal field of view of the optical system, and f is the effective focal length of the optical system. As f increases, the imaging field of view FOV decreases accordingly. When the optical system satisfies the above conditional formula, a larger field of view FOV can be obtained at a certain effective focal length, thereby increasing the imaging range of telephoto for distant objects. In a specific embodiment, the F number of the optical system is less than 2.21, so that the optical system has a higher amount of light input, thereby providing better relative brightness and color control for telephoto shooting.

[0042] In one embodiment, the optical system satisfies the conditional formula: 1.9<(|R32|+|R42|) / f≤13.44; wherein R32 is the radius of curvature of the image side surface of the third lens at the optical axis, R42 is the radius of curvature of the image side surface of the fourth lens at the optical axis, and f is the effective focal length of the optical system. In the optical system, the third lens provides positive or negative refractive power, and the fourth lens provides positive refractive power, then the combination structure of the third lens and the fourth lens can offset most of the distortion and coma produced by the front lens. At the same time, when the optical system satisfies the above conditional formula, a reasonable setting of the radius of curvature can avoid the introduction of large spherical aberration and vertical axis chromatic aberration, which is conducive to the reasonable distribution of primary aberrations on each lens, thereby reducing tolerance sensitivity.

[0043] In one embodiment, the optical system satisfies the conditional formula: 3.3≤R51 / CT56<28.7; wherein R51 is the radius of curvature of the object side of the fifth lens at the near optical axis, and CT56 is the distance between the image side of the fifth lens and the object side of the sixth lens on the optical axis. In the optical system, the fifth lens provides positive or negative refractive power, adjusts the overall refractive power distribution of the lens group, helps to disperse aberrations, and obtain high resolution. At the same time, when the optical system satisfies the above conditional formula, the appropriate curvature change of the edge reduces the deflection angle of each field of view light at the edge; reasonable control of lens curvature and thickness can effectively reduce the difficulty of molding and assembly of the optical system.

[0044] In one embodiment, the optical system satisfies the conditional formula: 1.2<(CT1+CT2+CT3) / BF<2.1; wherein CT1 is the thickness of the first lens on the optical axis, CT2 is the thickness of the second lens on the optical axis, CT3 is the thickness of the third lens on the optical axis, and BF is the distance from the image side of the sixth lens to the closest imaging surface along the optical axis. In a specific embodiment, BF is greater than 0.75. Under this condition, the optical system and the electronic photosensitive chip can form a good matching relationship, and it is also more conducive to the installation of various module components. It can be understood that when the optical system satisfies the above conditional formula, the compact structure of the first lens, the second lens and the third lens helps to reduce TTL. At the same time, the reasonable control of the thickness spacing makes the aberrations produced by the first three lenses very small, thereby reducing the difficulty of balancing the aberrations of the optical system.

[0045] In one embodiment, the optical system satisfies the conditional formula: 1.0<SAG61 / CT6<2.9; wherein SAG61 is the axial distance between the intersection of the object side of the sixth lens and the optical axis and the farthest point of the surface along the optical axis to the imaging surface, and CT6 is the thickness of the sixth lens on the optical axis. By reasonably setting the value of SAG61 / CT6, a good deflection angle is provided for the deflection of light at the edge of the lens, avoiding aberrations that are difficult to correct due to excessive deflection, and at the same time reducing the difficulty of lens molding, thereby improving production yield.

[0046] In one embodiment, the optical system satisfies the condition:

[0047] 19<(|f3|+f4+|f5|) / (CT34+CT45+CT56)<103; where f3 is the effective focal length of the third lens, f4 is the effective focal length of the fourth lens, f5 is the effective focal length of the fifth lens, CT34 is the distance between the image side of the third lens and the object side of the fourth lens on the optical axis, CT45 is the distance between the image side of the fourth lens and the object side of the fifth lens on the optical axis, and CT56 is the distance between the image side of the fifth lens and the object side of the sixth lens on the optical axis. By reasonably setting the value of (|f3|+f4+|f5|) / (CT34+CT45+CT56), the spherical aberration and chromatic aberration generated by the front lens group can be effectively balanced, thereby improving the overall image quality.

[0048] In one embodiment, the optical system satisfies the condition: 2.7mm<TTL / FNO<3.1mm; wherein TTL is the distance from the object side of the first lens to the imaging surface of the optical system on the optical axis, and FNO is the aperture number of the optical system. By properly setting the value of TTL / FNO, the optical system can have a large aperture effect, and the detail effect of the optical system in telephoto shooting can be improved to a certain extent.

[0049] First embodiment

[0050] Please refer to Figure 1a and Figure 1b The optical system of this embodiment includes, in order from the object side to the image side along the optical axis:

[0051] The first lens L1 has positive refractive power, the object side surface S1 of the first lens L1 is convex near the optical axis and near the circumference, the image side surface S2 of the first lens L1 is concave near the optical axis, and the image side surface S2 is convex near the circumference;

[0052] The second lens L2 has a positive refractive power, the object side surface S3 of the second lens L2 is convex near the optical axis, the object side surface S3 is concave near the circumference, and the image side surface S4 of the second lens L2 is concave near the optical axis and near the circumference;

[0053] The third lens L3 has negative refractive power, the object side surface S5 of the third lens L3 is convex near the optical axis and near the circumference, and the image side surface S6 of the third lens L3 is concave near the optical axis and near the circumference;

[0054] The fourth lens L4 has a positive refractive power, the object side surface S7 of the fourth lens L4 is convex near the optical axis, the object side surface S7 is concave near the circumference, and the image side surface S8 of the fourth lens L4 is convex near the optical axis and near the circumference;

[0055] The fifth lens L5 has positive refractive power. The object side surface S9 of the fifth lens L5 is concave near the optical axis and near the circumference. The image side surface S10 of the fifth lens L5 is convex near the optical axis, and the image side surface S10 is concave near the circumference.

[0056] The sixth lens L6 has negative refractive power. The object-side surface S11 of the sixth lens L6 is convex near the optical axis, and the near circumference of the object-side surface S11 is concave. The image-side surface S12 of the sixth lens L6 is concave near the optical axis, and the near circumference of the image-side surface S12 is convex.

[0057] The materials of the first lens L1 to the sixth lens L6 are all plastic.

[0058] In addition, the optical system also includes an aperture STO, an infrared filter L7 and an imaging surface S15. The aperture STO is arranged on the side of the first lens L1 away from the second lens L2, and is used to control the amount of light entering. In other embodiments, the aperture STO can also be arranged between two adjacent lenses, or on other lenses. The infrared filter L7 is arranged on the image side of the sixth lens L6, which includes an object side surface S13 and an image side surface S14. The infrared 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 filter L7 is glass (Glass), and a film can be coated on the glass. The imaging surface S15 is the effective pixel area of ​​the electronic photosensitive chip.

[0059] 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 nm, and the units of Y radius, thickness and focal length are all millimeters (mm).

[0060] Table 1a

[0061]

[0062]

[0063] Wherein, f 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.

[0064] 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:

[0065]

[0066] 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.

[0067] Table 1b

[0068]

[0069]

[0070] 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.

[0071] Second embodiment

[0072] 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:

[0073] The first lens L1 has positive refractive power, the object side surface S1 of the first lens L1 is convex near the optical axis and near the circumference, the image side surface S2 of the first lens L1 is concave near the optical axis, and the image side surface S2 is convex near the circumference;

[0074] The second lens L2 has negative refractive power, the object side surface S3 of the second lens L2 is convex near the optical axis and near the circumference, and the image side surface S4 of the second lens L2 is concave near the optical axis and near the circumference;

[0075] The third lens L3 has negative refractive power, the object side surface S5 of the third lens L3 is convex near the optical axis and near the circumference, and the image side surface S6 of the third lens L3 is concave near the optical axis and near the circumference;

[0076] The fourth lens L4 has a positive refractive power, the object side surface S7 of the fourth lens L4 is concave near the optical axis and near the circumference, and the image side surface S8 of the fourth lens L4 is convex near the optical axis and near the circumference;

[0077] The fifth lens L5 has positive refractive power. The object side surface S9 of the fifth lens L5 is concave near the optical axis and near the circumference. The image side surface S10 of the fifth lens L5 is convex near the optical axis, and the image side surface S10 is concave near the circumference.

[0078] The sixth lens L6 has negative refractive power. The object-side surface S11 of the sixth lens L6 is convex near the optical axis and near the circumference. The image-side surface S12 of the sixth lens L6 is concave near the optical axis, and the image-side surface S12 is convex near the circumference.

[0079] The other structures of the second embodiment are the same as those of the first embodiment, and can be used as a reference.

[0080] 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 nm, and the units of the Y radius, thickness and focal length are all millimeters (mm).

[0081] Table 2a

[0082]

[0083] The meanings of the parameters in Table 2a are the same as those in the first embodiment.

[0084] 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.

[0085] Table 2b

[0086]

[0087]

[0088] Figure 2b The longitudinal spherical aberration curve, astigmatism curve and distortion curve of the optical system of the second embodiment are shown. Figure 2b It can be seen that the optical system provided in the second embodiment can achieve good imaging quality.

[0089] Third embodiment

[0090] 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:

[0091] The first lens L1 has positive refractive power, the object side surface S1 of the first lens L1 is convex near the optical axis and near the circumference, the image side surface S2 of the first lens L1 is concave near the optical axis, and the image side surface S2 is convex near the circumference;

[0092] The second lens L2 has positive refractive power, the object side surface S3 of the second lens L2 is convex near the optical axis and near the circumference, and the image side surface S4 of the second lens L2 is concave near the optical axis and near the circumference;

[0093] The third lens L3 has negative refractive power, the object side surface S5 of the third lens L3 is convex near the optical axis and near the circumference, and the image side surface S6 of the third lens L3 is concave near the optical axis and near the circumference;

[0094] The fourth lens L4 has a positive refractive power, the object side surface S7 of the fourth lens L4 is convex near the optical axis, the object side surface S7 is concave near the circumference, and the image side surface S8 of the fourth lens L4 is convex near the optical axis and near the circumference;

[0095] The fifth lens L5 has negative refractive power. The object side surface S9 of the fifth lens L5 is concave at the near optical axis and near the circumference. The image side surface S10 of the fifth lens L5 is convex at the near optical axis, and the near circumference of the image side surface S10 is concave.

[0096] The sixth lens L6 has negative refractive power. The object-side surface S11 of the sixth lens L6 is convex near the optical axis, and the near circumference of the object-side surface S11 is concave. The image-side surface S12 of the sixth lens L6 is concave near the optical axis, and the near circumference of the image-side surface S12 is convex.

[0097] The other structures of the third embodiment are the same as those of the first embodiment, and can be used as a reference.

[0098] 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 nm, and the units of Y radius, thickness and focal length are all millimeters (mm).

[0099] Table 3a

[0100]

[0101] The meanings of the parameters in Table 3a are the same as those in the first embodiment.

[0102] 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.

[0103] Table 3b

[0104]

[0105] Figure 3b The longitudinal spherical aberration curve, astigmatism curve and distortion curve of the optical system of the third embodiment are shown. 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 positive refractive power, the object side surface S1 of the first lens L1 is convex near the optical axis and near the circumference, the image side surface S2 of the first lens L1 is concave near the optical axis, and the image side surface S2 is convex near the circumference;

[0109] The second lens L2 has negative refractive power. The object side surface S3 of the second lens L2 is convex near the optical axis, and the object side surface S3 is concave near the circumference. The image side surface S4 of the second lens L2 is concave near the optical axis, and the image side surface S4 is convex near the circumference.

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

[0111] The fourth lens L4 has a positive refractive power. The object side surface S7 of the fourth lens L4 is convex near the optical axis and near the circumference. The image side surface S8 of the fourth lens L4 is concave near the optical axis, and the image side surface S8 is convex near the circumference.

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

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

[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 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] Figure 4b The longitudinal spherical aberration curve, astigmatism curve and distortion curve of the optical system of the fourth embodiment are shown. Figure 4b It can be seen that the optical system provided in the fourth embodiment can achieve good imaging quality.

[0123] Fifth embodiment

[0124] 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:

[0125] The first lens L1 has positive refractive power, the object side surface S1 of the first lens L1 is convex near the optical axis and near the circumference, the image side surface S2 of the first lens L1 is concave near the optical axis, and the image side surface S2 is convex near the circumference;

[0126] The second lens L2 has negative refractive power, the object side surface S3 of the second lens L2 is convex near the optical axis and near the circumference, and the image side surface S4 of the second lens L2 is concave near the optical axis and near the circumference;

[0127] The third lens L3 has positive refractive power, the object side surface S5 of the third lens L3 is convex near the optical axis and near the circumference, and the image side surface S6 of the third lens L3 is convex near the optical axis and near the circumference;

[0128] The fourth lens L4 has a positive refractive power, the object side surface S7 of the fourth lens L4 is convex near the optical axis and near the circumference, and the image side surface S8 of the fourth lens L4 is concave near the optical axis and near the circumference;

[0129] The fifth lens L5 has positive refractive power. The object side surface S9 of the fifth lens L5 is convex near the optical axis, and the near circumference of the object side surface S9 is concave. The image side surface S10 of the fifth lens L5 is convex near the optical axis, and the near circumference of the image side surface S10 is concave.

[0130] The sixth lens L6 has negative refractive power. The object side surface S11 of the sixth lens L6 is concave near the optical axis and near the circumference. The image side surface S12 of the sixth lens L6 is concave near the optical axis, and the image side surface S12 is convex near the circumference.

[0131] The other structures of the fifth embodiment are the same as those of the first embodiment, and can be referred to herein.

[0132] 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 587 nm, and the units of Y radius, thickness and focal length are all millimeters (mm).

[0133] Table 5a

[0134]

[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] Table 5b

[0139]

[0140] Figure 5b The longitudinal spherical aberration curve, astigmatism curve and distortion curve of the optical system of the fifth embodiment are shown. 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 positive refractive power, the object side surface S1 of the first lens L1 is convex near the optical axis and near the circumference, the image side surface S2 of the first lens L1 is concave near the optical axis, and the image side surface S2 is convex near the circumference;

[0144] The second lens L2 has negative refractive power, the object side surface S3 of the second lens L2 is convex near the optical axis and near the circumference, and the image side surface S4 of the second lens L2 is concave near the optical axis and near the circumference;

[0145] The third lens L3 has positive refractive power, the object side surface S5 of the third lens L3 is convex near the optical axis and near the circumference, and the image side surface S6 of the third lens L3 is concave near the optical axis and near the circumference;

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

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

[0148] The sixth lens L6 has negative refractive power. The object-side surface S11 of the sixth lens L6 is convex near the optical axis, and the near circumference of the object-side surface S11 is concave. The image-side surface S12 of the sixth lens L6 is concave near the optical axis, and the near circumference of the image-side surface S12 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 are obtained using light with a wavelength of 587 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] Figure 6b The longitudinal spherical aberration curve, astigmatism curve and distortion curve of the optical system of the sixth embodiment are shown. Figure 6b It can be seen that the optical system provided in the sixth embodiment can achieve good imaging quality.

[0159] Seventh embodiment

[0160] Please refer to Figure 7a and Figure 7b The optical system of this embodiment includes, in order from the object side to the image side along the optical axis:

[0161] The first lens L1 has positive refractive power, the object side surface S1 of the first lens L1 is convex near the optical axis and near the circumference, the image side surface S2 of the first lens L1 is concave near the optical axis, and the image side surface S2 is convex near the circumference;

[0162] The second lens L2 has negative refractive power, the object side surface S3 of the second lens L2 is convex near the optical axis and near the circumference, and the image side surface S4 of the second lens L2 is concave near the optical axis and near the circumference;

[0163] The third lens L3 has negative refractive power, the object side surface S5 of the third lens L3 is concave near the optical axis and near the circumference, and the image side surface S6 of the third lens L3 is convex near the optical axis and near the circumference;

[0164] The fourth lens L4 has a positive refractive power, the object side surface S7 of the fourth lens L4 is convex near the optical axis and near the circumference, and the image side surface S8 of the fourth lens L4 is concave near the optical axis and near the circumference;

[0165] The fifth lens L5 has negative refractive power. The object side surface S9 of the fifth lens L5 is concave near the optical axis and near the circumference. The image side surface S10 of the fifth lens L5 is convex near the optical axis, and the image side surface S10 is concave near the circumference.

[0166] The sixth lens L6 has negative refractive power. The object-side surface S11 of the sixth lens L6 is convex near the optical axis, and the near circumference of the object-side surface S11 is concave. The image-side surface S12 of the sixth lens L6 is concave near the optical axis, and the near circumference of the image-side surface S12 is convex.

[0167] The other structures of the seventh embodiment are the same as those of the first embodiment, and can be referred to herein.

[0168] Table 7a 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 nm, and the units of Y radius, thickness and focal length are all millimeters (mm).

[0169] Table 7a

[0170]

[0171]

[0172] The meanings of the parameters in Table 7a are the same as those in the first embodiment.

[0173] Table 7b gives the coefficients of the higher-order terms that can be used for each aspherical mirror surface in the seventh embodiment, wherein each aspherical surface shape can be defined by the formula given in the first embodiment.

[0174] Table 7b

[0175]

[0176] Figure 7b The longitudinal spherical aberration curve, astigmatism curve and distortion curve of the optical system of the seventh embodiment are shown. Figure 7bIt can be seen that the optical system provided in the seventh embodiment can achieve good imaging quality.

[0177] Table 8 shows the values ​​of f*43 / ImgH, TTL / f, FOV / f, (|R32|+|R42|) / f, R51 / CT56, (CT1+CT2+CT3) / BF, SAG61 / CT6, (|f3|+f4+|f5|) / (CT34+CT45+CT56) of the optical systems of the first to seventh embodiments.

[0178] Table 8

[0179]

[0180] It can be seen from Table 8 that all embodiments can satisfy the following conditions: 45.5≤f*43 / ImgH<61.0, 0.89≤TTL / f<1.0, 5.5<FOV / f<8.2, 1.9<(|R32|+|R42|) / f≤13.44, 3.3≤R51 / CT56<28.7, 1.2<(CT1+CT2+CT3) / BF<2.1, 1.0<SAG61 / CT6<2.9, 19<(|f3|+f4+|f5|) / (CT34+CT45+CT56)<103.

[0181] The technical features of the above embodiments may be arbitrarily combined. To make the description concise, all possible combinations of the technical features in the above embodiments are not described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0182] The above embodiments only express several implementation methods of the present invention, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the present invention. It should be pointed out that, for those of ordinary skill in the art, several modifications and improvements can be made without departing from the concept of the present invention, and these all belong to the protection scope of the present invention. Therefore, the protection scope of the present invention shall be subject to the attached claims.

Claims

1. An optical system, characterized in that: There are six lenses with refractive power, including the following from the object side to the image side along the optical axis: A first lens has positive refractive power, the object side surface of the first lens is convex, and the image side surface of the first lens near the optical axis is concave; A second lens has refractive power, wherein 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; A third lens has refractive power, and both the object side surface and the image side surface of the third lens are aspherical surfaces; a fourth lens having positive refractive power, wherein both the object side surface and the image side surface of the fourth lens are aspherical surfaces; a fifth lens having refractive power, wherein both the object side surface and the image side surface of the fifth lens are aspherical surfaces; a sixth lens having negative refractive power, wherein the image side surface of the sixth lens is concave near the optical axis, the image side surface of the sixth lens is convex near the circumference, 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 F number of the optical system is less than or equal to 2.21; The optical system satisfies the condition: 0.89≤TTL / f<1.0; Wherein, TTL is the distance from the object side surface of the first lens to the imaging surface of the optical system on the optical axis, and f is the effective focal length of the optical system.

2. The optical system according to claim 1, characterized in that The optical system satisfies the condition: 45.5≤f*43 / ImgH<61.0; Wherein, f is the effective focal length of the optical system, and ImgH is the diagonal length of the effective imaging area of ​​the optical system on the imaging plane.

3. The optical system according to claim 1, characterized in that The optical system satisfies the condition: 5.5° / mm<FOV / f<8.2° / mm; Wherein, FOV is the diagonal field of view of the optical system, and f is the effective focal length of the optical system.

4. The optical system according to claim 1, characterized in that The optical system satisfies the condition: 1.9<(|R32|+|R42|) / f≤13.44; Wherein, R32 is the curvature radius of the image side surface of the third lens at the optical axis, R42 is the curvature radius of the image side surface of the fourth lens at the optical axis, and f is the effective focal length of the optical system.

5. The optical system according to claim 1, characterized in that The optical system satisfies the condition: 3.3≤R51 / CT56<28.7; Wherein, R51 is the curvature radius of the object side surface of the fifth lens on the optical axis, and CT56 is the distance between the image side surface of the fifth lens and the object side surface of the sixth lens on the optical axis.

6. The optical system according to claim 1, characterized in that The optical system satisfies the condition: 1.2<(CT1+CT2+CT3) / BF<2.1; Among them, CT1 is the thickness of the first lens on the optical axis, CT2 is the thickness of the second lens on the optical axis, CT3 is the thickness of the third lens on the optical axis, and BF is the closest distance from the image side of the sixth lens to the imaging plane along the optical axis.

7. The optical system according to claim 1, characterized in that The optical system satisfies the condition: 1.0<SAG61 / CT6<2.9; Among them, SAG61 is the axial distance between the intersection of the object side surface of the sixth lens and the optical axis and the farthest point of the surface along the optical axis to the imaging surface, and CT6 is the thickness of the sixth lens on the optical axis.

8. The optical system according to claim 1, characterized in that The optical system satisfies the condition: 19<(|f3|+f4+|f5|) / (CT34+CT45+CT56)<103; Among them, f3 is the effective focal length of the third lens, f4 is the effective focal length of the fourth lens, f5 is the effective focal length of the fifth lens, CT34 is the distance between the image side surface of the third lens and the object side surface of the fourth lens on the optical axis, CT45 is the distance between the image side surface of the fourth lens and the object side surface of the fifth lens on the optical axis, and CT56 is the distance between the image side surface of the fifth lens and the object side surface of the sixth lens on the optical axis.

9. The optical system according to claim 1, characterized in that The optical system satisfies the condition: 2.7mm<TTL / FNO<3.1mm; Wherein, TTL is the distance from the object side surface of the first lens to the imaging surface of the optical system on the optical axis, and FNO is the aperture number of the optical system.

10. A lens module, characterized in that: The optical system comprises a lens barrel, an electronic photosensitive chip and the optical system as claimed in any one of claims 1 to 9, wherein the first lens to the sixth lens of the optical system are installed in the lens barrel, and the electronic photosensitive chip is arranged on the image side of the optical system for converting light of an object passing through the first lens to the sixth lens and incident on the electronic photosensitive chip into an electrical signal of an image.

11. An electronic device, characterized in that: It comprises a shell and the lens module as claimed in claim 10, wherein the lens module is arranged in the shell.

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