Optical system

Abstract

An optical system of the present invention, in the direction from the object side to the image side along the optical axis, sequentially includes: a first lens with a positive focal power, a second lens with a positive or negative focal power, a third lens with a negative focal power, a fourth lens with a positive focal power, a fifth lens with a negative focal power, a sixth lens with a positive focal power, and a seventh lens with a negative focal power. The optical system further includes a diaphragm, and the diaphragm is disposed between the third lens and the fourth lens; the first lens is a convex-convex lens in the paraxial region; the image side surface of the third lens is a concave surface in the paraxial region. In the present invention, by reasonably distributing the focal powers of each lens and optimizing the shapes of each lens, the resolution can reach 60 million pixels, the imaging target surface can reach 1 / 1.7", the maximum aperture is FNO1.6, and seven plastic lenses are used, which have the characteristics of small volume, light weight, and low cost. Its CRA can be adapted to various large target surface sensors on the market, with broad application prospects and enhanced market competitiveness.

Description

Technical Field

[0001] The present invention relates to the field of optical imaging, and particularly to an optical system. Background Art

[0002] Optical lenses are widely used in fields such as drone shooting and mobile phone photography. With the continuous development of imaging chip technology and optical materials, the captured videos can be made clearer and the lens specification range can also be made wider. Larger apertures, higher resolution, and lighter weight are the constant themes in lens development. However, lenses that meet these performance requirements generally have higher costs, larger volumes, and increased weights. Therefore, how to reduce costs and decrease the volume while ensuring the lens performance is a technical problem that needs to be solved for mobile phone lenses. Summary of the Invention

[0003] The purpose of the present invention is to solve the above problems and provide an optical system with a large aperture, high resolution, light weight, small volume, and low cost.

[0004] To achieve the above purpose, the present invention provides an optical system, which sequentially includes, along the optical axis from the object side to the image side: a first lens with a positive optical power, a second lens with a positive or negative optical power, a third lens with a negative optical power, a fourth lens with a positive optical power, a fifth lens with a negative optical power, a sixth lens with a positive optical power, and a seventh lens with a negative optical power. The optical system further includes a diaphragm, and the diaphragm is disposed between the third lens and the fourth lens;

[0005] The first lens is a convex-convex lens in the paraxial region;

[0006] The image side surface of the third lens is a concave surface in the paraxial region;

[0007] The sixth lens is a convex-concave lens in the paraxial region.

[0008] According to one aspect of the present invention, along the optical axis from the object side to the image side, the second lens is a convex-concave lens in the paraxial region; the fourth lens is a convex-convex lens in the paraxial region; the seventh lens is a concave-concave lens in the paraxial region;

[0009] The image side surface of the fifth lens is a concave surface in the paraxial region.

[0010] According to one aspect of the present invention, the first lens, the second lens, the third lens, the fourth lens, the fifth lens, the sixth lens, and the seventh lens are aspherical lenses.

[0011] According to one aspect of the present invention, the first lens, the second lens, the third lens, the fourth lens, the fifth lens, the sixth lens, and the seventh lens are plastic lenses.

[0012] According to one aspect of the present invention, the air gap C45 between the fourth lens and the fifth lens and the total lens length TTL of the optical system satisfy the following relationship: 0.003 ≤ C45 / TTL ≤ 0.05.

[0013] According to one aspect of the present invention, the back focal length BFL of the optical system and the distance TL on the optical axis from the object side surface of the first lens to the image side surface of the seventh lens satisfy the following relationship: 0.08 ≤ BFL / TL ≤ 0.15.

[0014] According to one aspect of the present invention, the effective focal length F of the optical system and the total lens length TTL of the optical system satisfy the following relationship: 1.2 ≤ TTL / F ≤ 1.7.

[0015] According to one aspect of the present invention, the combined focal length Fb of the fourth lens, the fifth lens, the sixth lens and the seventh lens and the effective focal length F of the optical system satisfy the following relationship: 0.4 ≤ Fb / F ≤ 0.8.

[0016] According to one aspect of the present invention, the focal length f1 of the first lens and the effective focal length F of the optical system satisfy the following relationship: 0.7 ≤ f1 / F ≤ 1.6.

[0017] According to one aspect of the present invention, the focal length f2 of the second lens and the effective focal length F of the optical system satisfy the following relationship: -228 ≤ f2 / F ≤ 2.4.

[0018] According to one aspect of the present invention, the focal length f3 of the third lens and the effective focal length F of the optical system satisfy the following relationship: -0.9 ≤ f3 / F ≤ -0.4.

[0019] According to one aspect of the present invention, the focal length f4 of the fourth lens and the effective focal length F of the optical system satisfy the following relationship: 0.3 ≤ f4 / F ≤ 0.7.

[0020] According to one aspect of the present invention, the focal length f5 of the fifth lens and the effective focal length F of the optical system satisfy the following relationship: -3.8 ≤ f5 / F ≤ -1.2.

[0021] According to one aspect of the present invention, the focal length f6 of the sixth lens and the effective focal length F of the optical system satisfy the following relationship: 0.6 ≤ f6 / F ≤ 1.4.

[0022] According to one aspect of the present invention, the focal length f7 of the seventh lens and the effective focal length F of the optical system satisfy the following relationship: -0.7 ≤ f7 / F ≤ -0.3.

[0023] According to the concept of the present invention, the optical system of the present invention can achieve high resolution performance of the lens by reasonably distributing the optical power of each lens and optimizing the shape of each lens. The resolution can reach 60 million pixels, the imaging target surface can reach 1 / 1.7", the maximum aperture is FNO1.6, and seven plastic lenses are used, which have the characteristics of small volume, light weight and low cost. Its CRA can be adapted to various large target surface sensors on the market, with broad application prospects and enhanced market competitiveness.

[0024] According to one aspect of the present invention, by optimizing the shape of each lens and reasonably distributing the optical power of each lens, the resolution of the optical system can reach up to 60 million pixels and can be applicable to current mainstream large target surface sensors.

[0025] According to one aspect of the present invention, by setting each lens as a plastic aspheric lens, the production cost is effectively reduced, and it has the advantages of small volume and light weight.

[0026] According to one aspect of the present invention, by reasonably controlling the air gap between the fourth lens and the fifth lens, it is beneficial to the smooth transition of light, improves the production yield of the product, reduces the production cost. At the same time, appropriately restricting the total length of the lens of the optical system is beneficial to ensuring the miniaturization of the lens.

[0027] According to one aspect of the present invention, by reasonably controlling the proportional relationship between the back focal length of the optical system and the length of the lens group of the optical system, the lens CRA can be matched with the current mainstream large target surface sensor, improving the versatility of the lens.

[0028] According to one aspect of the present invention, by reasonably configuring the ratio relationship between the focal length of the lens group behind the aperture STO and the system focal length, the optical system has the characteristic of small volume. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 It is a schematic structural diagram of the optical system of Embodiment 1 in the present invention;

[0030] Figure 2 It is a schematic structural diagram of the optical system of Embodiment 2 in the present invention;

[0031] Figure 3 It is a schematic structural diagram of the optical system of Embodiment 3 in the present invention;

[0032] Figure 4 It is a schematic structural diagram of the optical system of Embodiment 4 in the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0033] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for the embodiments. Obviously, the drawings in the following description are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0034] When describing the embodiments of the present invention, the orientation or positional relationships expressed by the terms "longitudinal", "transverse", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer" are based on the orientation or positional relationships shown in the relevant drawings. It is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation. Therefore, the above terms should not be construed as limiting the present invention.

[0035] The present invention will be described in detail below in conjunction with the drawings and specific embodiments. The embodiments cannot be elaborated one by one here, but the embodiments of the present invention are not limited to the following embodiments.

[0036] Figure 1 is a schematic structural diagram of an optical system showing an embodiment of the present invention. As Figure 1 shown, the optical system of the present invention, in the direction from the object side to the image side along the optical axis, successively includes: a first lens L1 with a positive optical power, a second lens L2 with a positive or negative optical power, a third lens L3 with a negative optical power, a fourth lens L4 with a positive optical power, a fifth lens L5 with a negative optical power, a sixth lens L6 with a positive optical power, and a seventh lens L7 with a negative optical power. The optical system also includes a stop STO, and the stop STO is disposed between the third lens L3 and the fourth lens L4;

[0037] The first lens L1 is a convex-convex lens in the paraxial region;

[0038] The image side surface of the third lens L3 is a concave surface in the paraxial region;

[0039] The sixth lens L6 is a convex-concave lens in the paraxial region.

[0040] In the present invention, in the direction from the object side to the image side along the optical axis, the second lens L2 is a convex-concave lens in the paraxial region; the fourth lens L4 is a convex-convex lens in the paraxial region; the seventh lens L7 is a concave-concave lens in the paraxial region;

[0041] The image side surface of the fifth lens L5 is a concave surface in the paraxial region.

[0042] By optimizing the shapes of the individual lenses and reasonably distributing the optical powers of the lenses, the resolution of the optical system is as high as 60 million pixels and it can be applied to the current mainstream large-format sensors.

[0043] In the present invention, the first lens L1, the second lens L2, the third lens L3, the fourth lens L4, the fifth lens L5, the sixth lens L6 and the seventh lens L7 are aspherical lenses.

[0044] Among them, the aspherical surface satisfies the following formula:

[0045]

[0046] In the formula, z is the axial distance from the vertex of the surface at the position perpendicular to the optical axis with a height of h along the optical axis direction; c represents the curvature at the vertex of the aspherical surface; k is the conic coefficient; A4, A6, A8, A 10 、A 12 、A 14 、A 16 ··· represent the aspherical coefficients of the fourth order, sixth order, eighth order, tenth order, twelfth order, fourteenth order, sixteenth order ··· respectively.

[0047] In the present invention, the first lens L1, the second lens L2, the third lens L3, the fourth lens L4, the fifth lens L5, the sixth lens L6 and the seventh lens L7 are plastic lenses.

[0048] By setting each lens as a plastic aspherical lens, the production cost is effectively reduced, and it has the advantages of small volume and light weight.

[0049] In the present invention, the air gap C45 between the fourth lens L4 and the fifth lens L5 and the total lens length TTL of the optical system satisfy the following relationship: 0.003 ≤ C45 / TTL ≤ 0.05.

[0050] By reasonably controlling the air gap between the fourth lens and the fifth lens, it is beneficial to the smooth transition of light, improves the production yield of the product, reduces the production cost. At the same time, appropriately limiting the total lens length of the optical system is beneficial to ensuring the miniaturization of the lens.

[0051] In the present invention, the back focal length BFL of the optical system and the distance TL on the optical axis from the object side of the first lens L1 to the image side of the seventh lens L7 satisfy the following relationship: 0.08 ≤ BFL / TL ≤ 0.15.

[0052] By reasonably controlling the proportional relationship between the back focal length of the optical system and the length of the lens group of the optical system, the CRA of the lens can match the current mainstream large-format sensor, improving the versatility of the lens.

[0053] In the present invention, the effective focal length F of the optical system and the total lens length TTL of the optical system satisfy the following relationship:

[0054] 1.2 ≤ TTL / F ≤ 1.7.

[0055] In the present invention, the combined focal length Fb of the fourth lens L4, the fifth lens L5, the sixth lens L6 and the seventh lens L7 and the effective focal length F of the optical system satisfy the following relationship: 0.4 ≤ Fb / F ≤ 0.8.

[0056] By reasonably configuring the ratio relationship between the focal length of the lens group behind the aperture STO and the system focal length, the optical system has the characteristic of small volume.

[0057] In the present invention, the focal length f1 of the first lens L1 and the effective focal length F of the optical system satisfy the following relationship: 0.7 ≤ f1 / F ≤ 1.6; the focal length f2 of the second lens L2 and the effective focal length F of the optical system satisfy the following relationship: -228 ≤ f2 / F ≤ 2.4; the focal length f3 of the third lens L3 and the effective focal length F of the optical system satisfy the following relationship: -0.9 ≤ f3 / F ≤ -0.4; the focal length f4 of the fourth lens L4 and the effective focal length F of the optical system satisfy the following relationship: 0.3 ≤ f4 / F ≤ 0.7; the focal length f5 of the fifth lens L5 and the effective focal length F of the optical system satisfy the following relationship: -3.8 ≤ f5 / F ≤ -1.2; the focal length f6 of the sixth lens L6 and the effective focal length F of the optical system satisfy the following relationship: 0.6 ≤ f6 / F ≤ 1.4; the focal length f7 of the seventh lens L7 and the effective focal length F of the optical system satisfy the following relationship: -0.7 ≤ f7 / F ≤ -0.3.

[0058] The following gives four specific embodiments according to the above settings of the present invention to specifically illustrate the optical system according to the present invention. Since the optical system according to the present invention has a total of seven lenses, plus the aperture STO, the protective glass C and the image plane IMA, there are a total of 18 surfaces. For the convenience of description, each surface is numbered S1, S2 to S18.

[0059] The data of the four groups of embodiments are as shown in Table 1 below:

[0060] Conditional Example 1 Example 2 Example 3 Example 4 0.7 ≤ f1 / F ≤ 1.6 1.072 0.882 1.364 1.290 -228 ≤ f2 / F ≤ 2.4 -128.215 -2.537 -226.531 2.251 -0.9 ≤ f3 / F ≤ -0.4 -0.651 -0.710 -0.736 -0.553 0.3 ≤ f4 / F ≤ 0.7 0.487 0.480 0.526 0.585 -3.8 ≤ f5 / F ≤ -1.2 -1.659 -1.357 -2.361 -3.635 0.6 ≤ f6 / F ≤ 1.4 0.852 0.755 0.900 1.256 -0.7 ≤ f7 / F ≤ -0.3 -0.498 -0.472 -0.511 -0.604 0.003 ≤ C45 / TTL ≤ 0.05 0.032 0.019 0.030 0.007 0.08 ≤ BFL / TL ≤ 0.15 0.102 0.094 0.103 0.104 1.2 ≤ TTL / f ≤ 1.7 1.354 1.369 1.549 1.362 0.4 ≤ fb / f ≤ 0.8 0.614 0.625 0.537 0.585

[0061] Table 1

[0062] Example 1:

[0063] Figure 1 It is a schematic structural diagram of the optical system of Example 1 in the present invention.

[0064] In Embodiment 1, the aperture FNO of the optical system is 1.80, and the total length of the lens is 10.55 mm; the second lens L2 has a negative optical power, and the third lens L3 and the fifth lens L5 are plano-concave lenses in the paraxial region.

[0065] The following Table 2 lists the relevant parameters of each lens in this embodiment, including the surface type, the curvature radius R value, the thickness, the refractive index of the material, and the Abbe number:

[0066]

[0067]

[0068] Table 2

[0069] In this embodiment, the aspheric data is shown in Table 3 below, where K is the conic constant of the surface, and A4, A6, A8, A10, A12, A14, A16 are the aspheric coefficients of the fourth, sixth, eighth, tenth, twelfth, fourteenth, and sixteenth orders respectively:

[0070] Surface serial number K A4 A6 A8 A10 A12 A14 A16 S1 5.452 -5.016E-05 1.824E-05 -5.204E-07 1.319E-07 -9.740E-09 0.000E+00 0.000E+00 S2 0.000 5.628E-03 -5.765E-04 5.659E-05 -4.331E-06 1.662E-07 0.000E+00 0.000E+00 S3 -2.515 -2.268E-03 -2.917E-04 8.518E-06 2.972E-06 -1.389E-07 0.000E+00 0.000E+00 S4 -1.567 -1.154E-02 1.149E-03 -8.195E-05 -3.703E-07 7.375E-07 0.000E+00 0.000E+00 S5 -4.068 -3.814E-03 3.838E-04 -3.375E-04 9.911E-06 3.349E-06 -4.387E-08 0.000E+00 S6 -1.604 1.617E-03 4.068E-03 3.644E-04 -1.056E-03 1.288E-04 -8.210E-07 0.000E+00 S8 1.084 -1.050E-02 7.054E-03 -2.574E-03 6.654E-04 -2.092E-04 1.351E-05 9.567E-07 S9 -1.558 -1.887E-02 8.232E-03 -2.534E-03 8.832E-04 -2.696E-05 -2.257E-05 3.059E-07 S10 0.000 -3.559E-02 5.025E-03 1.430E-03 -1.864E-03 4.444E-04 -4.334E-05 2.394E-06 S11 4.152 -2.192E-02 5.049E-03 -1.601E-04 -3.538E-04 1.217E-04 -1.249E-05 -1.391E-07 S12 -7.888 -6.377E-04 -1.777E-03 6.436E-04 -1.347E-04 2.264E-06 -4.854E-06 -4.818E-08 S13 6.759 9.376E-03 -4.974E-03 5.342E-04 7.436E-05 -7.699E-06 -2.769E-07 -1.510E-09 S14 -2.144 -1.206E-02 -6.520E-03 1.905E-03 -8.910E-05 -1.619E-06 -7.417E-08 1.523E-10 S15 4.394 -2.434E-02 2.165E-03 -1.592E-04 4.762E-06 -1.846E-07 4.139E-09 -3.763E-13

[0071] Table 3

[0072] See Figure 1 , in combination with Tables 1 to 3, in this embodiment, the aperture of the optical system can reach 1.8, the resolution can reach 60 million pixels, the imaging target surface can reach 1 / 1.7", the total length of the lens is 10.55 mm, and it has the characteristics of miniaturization, low cost, and high performance.

[0073] Embodiment 2:

[0074] Figure 2 is a schematic structural diagram of the optical system of Embodiment 2 in the present invention.

[0075] In Embodiment 2, the aperture FNO of the optical system is 1.86, and the total length of the lens is 11.95 mm; the second lens has a negative optical power, the third lens L3 is a plano-concave lens in the paraxial region, and the fifth lens L5 is a concave-concave lens in the paraxial region.

[0076] The following Table 4 lists the relevant parameters of each lens in this embodiment, including the surface type, the curvature radius, the thickness, the refractive index of the material, and the Abbe number:

[0077] Surface serial number Surface type R value Thickness Refractive index Abbe number S1 Aspherical surface 5.341 2.674 1.54 60.0 S2 Aspherical surface -15.097 0.060 S3 Aspherical surface 52.731 1.689 1.62 25.8 S4 Aspherical surface 10.708 0.065 S5 Aspherical surface 8.963 0.600 1.57 37.5 S6 Aspherical surface 2.464 0.535 S7(STO) Spherical surface Infinity -0.424 S8 Aspherical surface 2.807 1.086 1.54 60.0 S9 Aspherical surface -10.576 0.224 S10 Aspherical surface -25.181 1.418 1.61 25.6 S11 Aspherical surface 10.461 0.210 S12 Aspherical surface -70.946 1.670 1.57 37.5 S13 Aspherical surface -3.582 0.517 S14 Aspherical surface -3.231 0.600 1.54 60.0 S15 Aspherical surface 8.445 0.500 S16 Spherical surface Infinity 0.21 1.52 64.2 S17 Spherical surface Infinity 0.317 S18(IMA) Spherical surface Infinity - - -

[0078] Table 4

[0079] In this embodiment, the aspherical data is shown in Table 5 below, where K is the conic constant of the surface, and A4, A6, A8, A10, A12, A14, A16 are the aspherical coefficients of the fourth, sixth, eighth, tenth, twelfth, fourteenth, and sixteenth orders respectively:

[0080] Surface serial number K A4 A6 A8 A10 A12 A14 A16 S1 4.117 -3.002E-05 3.939E-05 -4.976E-06 4.088E-07 -1.267E-08 0.000E+00 0.000E+00 S2 0.000 6.378E-03 -7.190E-04 5.442E-05 -3.312E-06 1.193E-07 0.000E+00 0.000E+00 S3 0.000 -1.600E-03 -1.816E-04 -1.283E-06 2.374E-06 -9.586E-08 0.000E+00 0.000E+00 S4 1.088 -1.279E-02 7.599E-04 -1.188E-04 1.006E-05 9.790E-07 0.000E+00 0.000E+00 S5 -3.271 -2.155E-03 -8.570E-04 -4.117E-04 2.848E-05 1.158E-05 -1.125E-06 0.000E+00 S6 -2.035 1.043E-03 5.166E-03 6.822E-04 -1.151E-03 9.367E-05 3.160E-06 0.000E+00 S8 7.368 -1.687E-02 9.332E-03 -1.537E-03 5.858E-04 -3.061E-04 3.115E-05 8.755E-06 S9 -2.810 -2.048E-02 7.072E-03 -1.784E-03 1.002E-03 -7.174E-05 -4.345E-05 1.872E-05 S10 0.000 -2.713E-02 5.236E-03 -5.968E-04 -9.310E-04 9.430E-04 -4.330E-04 6.848E-05 S11 1.781 -9.020E-03 -5.319E-04 1.480E-03 -4.163E-04 -6.954E-07 1.567E-05 -1.860E-06 S12 0.000 -4.846E-04 -2.589E-03 1.381E-03 -2.724E-04 -1.048E-05 1.419E-05 -3.116E-06 S13 1.920 8.649E-03 -4.214E-03 4.049E-04 4.242E-05 -2.763E-06 2.704E-07 -8.482E-08 S14 -3.236 -1.361E-02 -5.040E-03 1.341E-03 -8.287E-05 5.958E-06 3.128E-07 -9.964E-08 S15 5.186 -2.279E-02 1.853E-03 -1.330E-04 2.174E-06 -1.458E-07 4.214E-08 -2.982E-09

[0081] Table 5

[0082] See Figure 2 , in combination with Table 1, Table 4 and Table 5, in this embodiment, the aperture of the optical system can reach 1.86, the resolution can reach 60 million pixels, the imaging target surface can reach 1 / 1.7", the total length of the lens is 11.95 mm, and it has the characteristics of miniaturization, low cost and high performance.

[0083] Embodiment 3:

[0084] Figure 3 is a schematic structural diagram of the optical system of Embodiment 3 in the present invention.

[0085] In Embodiment 3, the aperture FNO of the optical system is 1.60, and the total length of the lens is 10.69 mm; the second lens has a negative optical power, and the third lens L3 and the fifth lens L5 are convex-concave lenses in the paraxial region.

[0086] The following Table 6 lists the relevant parameters of each lens in this embodiment, including the surface type, radius of curvature, thickness, refractive index of the material, and Abbe number:

[0087] Surface serial number Surface type R value Thickness Refractive index Abbe number S1 Aspherical surface 12.389 2.63 1.53 56.3 S2 Aspherical surface -7.629 0.04 S3 Aspherical surface 14.208 1.28 1.67 19.3 S4 Aspherical surface 13.511 0.29 S5 Aspherical surface 26.253 0.51 1.58 30.2 S6 Aspherical surface 2.64 0.61 S7(STO) Spherical surface Infinity -0.47 S8 Aspherical surface 2.736 1.27 1.54 60.0 S9 Aspherical surface -5.98 0.33 S10 Aspherical surface 6.431 0.66 1.64 23.5 S11 Aspherical surface 3.817 0.36 S12 Aspherical surface -19.987 1.09 1.58 30.2 S13 Aspherical surface -3.124 0.74 S14 Aspherical surface -2.925 0.35 1.54 60.0 S15 Aspherical surface 5.856 0.52 S16 Spherical surface Infinity 0.21 1.52 64.2 S17 Spherical surface Infinity 0.27 S18(IMA) Spherical surface Infinity 0

[0088] Table 6

[0089] In this embodiment, the aspherical data is shown in Table 7 below, where K is the conic constant of the surface, and A4, A6, A8, A10, A12, A14, A16 are the aspherical coefficients of the fourth, sixth, eighth, tenth, twelfth, fourteenth, and sixteenth orders respectively:

[0090]

[0091]

[0092] Table 7

[0093] See Figure 3 , in combination with Table 1, Table 6 and Table 7, in this embodiment, the aperture of the optical system can reach 1.6, the resolution can reach 60 million pixels, the imaging target surface can reach 1 / 1.7", the total length of the lens is 10.69 mm, and it has the characteristics of miniaturization, low cost and high performance.

[0094] Embodiment 4:

[0095] Figure 4 This is a schematic structural diagram of the optical system of Embodiment 4 in the present invention.

[0096] In Embodiment 4, the aperture FNO of the optical system is 1.62, and the total lens length is 10.35 mm; the second lens has a positive optical power, the third lens L3 is a plano-concave lens in the paraxial region, and the fifth lens L5 is a convex-concave lens in the paraxial region.

[0097] The following Table 8 lists the relevant parameters of each lens in this embodiment, including surface type, radius of curvature, thickness, refractive index of the material, and Abbe number:

[0098]

[0099]

[0100] Table 8

[0101] In this embodiment, the aspheric data is shown in the following Table 9, where K is the conic constant of the surface, and A4, A6, A8, A10, A12, A14, A16 are the aspheric coefficients of the fourth order, sixth order, eighth order, tenth order, twelfth order, fourteenth order, and sixteenth order respectively:

[0102] Surface serial number K A4 A6 A8 A10 A12 A14 A16 S1 1.548 -4.232E-04 4.293E-05 -1.424E-05 8.507E-07 -5.017E-08 0.000E+00 0.000E+00 S2 1.125 6.818E-03 -6.932E-04 5.728E-05 -2.091E-06 1.357E-08 0.000E+00 0.000E+00 S3 1.792 -3.026E-03 -2.569E-04 -9.089E-05 1.310E-05 5.312E-07 -7.183E-08 0.000E+00 S4 0.000 -5.836E-03 -7.921E-04 1.242E-04 1.245E-05 -2.063E-06 6.686E-08 0.000E+00 S5 0.000 -1.032E-03 4.564E-04 -1.022E-04 1.532E-06 3.355E-06 -3.859E-07 0.000E+00 S6 -5.453 1.313E-02 1.554E-03 1.325E-04 -4.396E-04 9.723E-05 -8.235E-06 0.000E+00 S8 8.816 -5.843E-03 4.754E-03 -1.569E-03 4.605E-04 -2.084E-04 5.449E-05 -5.490E-06 S9 -6.684 -1.349E-02 6.896E-03 -2.699E-03 8.202E-04 -7.957E-05 9.851E-06 -4.409E-06 S10 0.000 -3.091E-02 4.804E-03 -1.631E-03 -3.894E-04 7.439E-04 -2.832E-04 3.482E-05 S11 -4.427 -1.538E-02 -6.478E-04 1.183E-06 4.365E-04 -1.254E-04 -5.611E-06 8.583E-06 S12 0.000 -9.781E-03 -2.234E-03 -1.540E-03 1.543E-03 -8.193E-04 2.156E-04 -1.931E-05 S13 7.925 -2.226E-03 -2.078E-03 4.886E-04 -1.060E-04 4.041E-06 2.510E-06 2.711E-07 S14 5.839 -3.281E-02 2.802E-03 7.285E-04 -2.607E-04 1.875E-05 4.147E-06 -4.349E-07 S15 1.609 -2.875E-02 4.280E-03 -5.406E-04 3.345E-05 -1.973E-07 -1.003E-07 4.305E-09

[0103] Table 9

[0104] See Figure 4 , in combination with Table 1, Table 8 and Table 9, in this embodiment, the aperture of the optical system can reach 1.62, the resolution can reach 60 million pixels, the imaging target surface can reach 1 / 1.7", the total lens length is 10.35 mm, and it has the characteristics of miniaturization, low cost and high performance.

[0105] An optical system of the present invention can achieve high resolution performance of the lens by reasonably distributing the optical power of each lens and optimizing the shape of each lens. The resolution can reach 60 million pixels, the imaging target surface can reach 1 / 1.7", the maximum aperture FNO is 1.6, and seven plastic lenses are used. It has the characteristics of small volume, light weight and low cost. Its CRA can be adapted to various large target surface sensors on the market, with broad application prospects and improved market competitiveness; by reasonably distributing the optical power of each lens, the resolution of the optical system is as high as 60 million pixels and can be applied to the current mainstream large target surface sensors; each lens is set as a plastic aspheric lens, effectively reducing the production cost, and having the advantages of small volume and light weight; reasonably controlling the air gap between the fourth lens and the fifth lens is beneficial to the smooth transition of light, improving the production yield of products and reducing the production cost. At the same time, appropriately limiting the total lens length of the optical system is beneficial to ensuring the miniaturization of the lens.

[0106] The above is only one embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various changes and modifications. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. An optical system, characterized in that, In the direction from the object side to the image side along the optical axis, it successively includes: a first lens (L1) with a positive focal power, a second lens (L2) with a positive or negative focal power, a third lens (L3) with a negative focal power, a fourth lens (L4) with a positive focal power, a fifth lens (L5) with a negative focal power, a sixth lens (L6) with a positive focal power, and a seventh lens (L7) with a negative focal power. There are a total of seven lenses with focal power. The optical system further includes a stop (STO), and the stop (STO) is disposed between the third lens (L3) and the fourth lens (L4); The first lens (L1) is a convex-convex lens in the paraxial region; The image side surface of the third lens (L3) is a concave surface in the paraxial region; The sixth lens (L6) is a convex-concave lens in the paraxial region; The combined focal length Fb of the fourth lens (L4), the fifth lens (L5), the sixth lens (L6), and the seventh lens (L7) and the effective focal length F of the optical system satisfy the following relationship: 0.4 ≤ Fb / F ≤ 0.

8.

2. The optical system according to claim 1, wherein In the direction from the object side to the image side along the optical axis, the second lens (L2) is a convex-concave lens in the paraxial region; the fourth lens (L4) is a convex-convex lens in the paraxial region; the seventh lens (L7) is a concave-concave lens in the paraxial region; The image side surface of the fifth lens (L5) is a concave surface in the paraxial region.

3. The optical system according to claim 1, wherein The first lens (L1), the second lens (L2), the third lens (L3), the fourth lens (L4), the fifth lens (L5), the sixth lens (L6), and the seventh lens (L7) are aspherical lenses.

4. The optical system according to claim 1, characterized in that, The first lens (L1), the second lens (L2), the third lens (L3), the fourth lens (L4), the fifth lens (L5), the sixth lens (L6), and the seventh lens (L7) are plastic lenses.

5. The optical system according to any one of claims 1 to 4, characterized in that The air gap C45 between the fourth lens (L4) and the fifth lens (L5) and the total lens length TTL of the optical system satisfy the following relationship: 0.003 ≤ C45 / TTL ≤ 0.

05.

6. The optical system according to any one of claims 1 to 4, characterized in that, The back focal length BFL of the optical system and the distance TL on the optical axis from the object side surface of the first lens (L1) to the image side surface of the seventh lens (L7) satisfy the following relationship: 0.08 ≤ BFL / TL ≤ 0.

15.

7. The optical system according to any one of claims 1 to 4, characterized in that, The effective focal length F of the optical system and the total lens length TTL of the optical system satisfy the following relationship: 1.2 ≤ TTL / F ≤ 1.

7.

8. The optical system according to any one of claims 1 to 4, characterized in that The focal length f1 of the first lens (L1) and the effective focal length F of the optical system satisfy the following relationship: 0.7 ≤ f1 / F ≤ 1.

6.

9. The optical system according to any one of claims 1 to 4, characterized in that, The focal length f2 of the second lens (L2) and the effective focal length F of the optical system satisfy the following relationship: -228 ≤ f2 / F ≤ 2.

4.

10. The optical system according to any one of claims 1 to 4, characterized in that, The focal length f3 of the third lens (L3) and the effective focal length F of the optical system satisfy the following relationship: -0.9 ≤ f3 / F ≤ -0.

4.

11. The optical system according to any one of claims 1 to 4, characterized in that, The focal length f4 of the fourth lens (L4) and the effective focal length F of the optical system satisfy the following relationship: 0.3 ≤ f4 / F ≤ 0.

7.

12. The optical system according to any one of claims 1 to 4, characterized in that, The focal length f5 of the fifth lens (L5) and the effective focal length F of the optical system satisfy the following relationship: -3.8 ≤ f5 / F ≤ -1.

2.

13. The optical system according to any one of claims 1 to 4, characterized in that, The focal length f6 of the sixth lens (L6) and the effective focal length F of the optical system satisfy the following relationship: 0.6 ≤ f6 / F ≤ 1.

4.

14. The optical system according to any one of claims 1 to 4, characterized in that, The focal length f7 of the seventh lens (L7) and the effective focal length F of the optical system satisfy the following relationship: -0.7 ≤ f7 / F ≤ -0.3.

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