Optical imaging system

Abstract

The present invention provides an optical imaging system. The optical imaging system includes a lens barrel and a lens group and a spacer element group disposed in the lens barrel. The lens group is composed of six lenses. The six lenses are, in order from the object side to the image side, a first lens with a negative optical power, a second lens with a positive optical power, a third lens with a positive optical power, a fourth lens with an optical power, a fifth lens with an optical power, and a sixth lens with an optical power; the spacer element group includes a first spacer element, a second spacer element, and a third spacer element; satisfying: 1 < Tr1r4 / Tr5r12 < 1.2; satisfying: -1.25 ≤ d2s / f12 < -0.5. The present invention solves the problem in the prior art that a six-piece optical imaging system has the problem of increasing the thickness of the front lens to meet a large field of view, resulting in discreteness.

Description

Technical Field

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

[0002] In the field of modern optical imaging technology, with the continuous improvement of the requirements for imaging quality, the design and manufacture of optical imaging systems face many challenges, especially for six-piece optical imaging systems. However, in order to meet the requirements of a large field of view and a large shooting range, the existing six-piece optical imaging systems often achieve this by increasing the thickness of the front lens. However, this design often leads to a more sensitive surface shape of the front lens and a thicker edge thickness, which is likely to cause the occurrence of discrete problems.

[0003] That is to say, the existing six-piece optical imaging systems have the problem of increasing the thickness of the front lens to meet the large field of view, resulting in discrete problems. Summary of the Invention

[0004] The main object of the present invention is to provide an optical imaging system to solve the problem that the existing six-piece optical imaging systems increase the thickness of the front lens to meet the large field of view, resulting in discrete problems.

[0005] To achieve the above object, according to one aspect of the present invention, there is provided an optical imaging system, including a lens barrel and a lens group and a spacer element group disposed in the lens barrel. The lens group is composed of six lenses. The six lenses are, in order from the object side to the image side, a first lens with a negative optical power, a second lens with a positive optical power, a third lens with a positive optical power, a fourth lens with an optical power, a fifth lens with an optical power, and a sixth lens with an optical power. Among them, the object side surface of the first lens is concave, and the image side surface is concave; the image side surface of the second lens is convex; the object side surface of the third lens is convex, and the image side surface is convex; the object side surface of the fourth lens is convex; the image side surface of the fifth lens is convex; there is an air gap between adjacent two of the first lens to the sixth lens; the spacer element group includes a first spacer element disposed between the first lens and the second lens and in partial contact with the image side surface of the first lens, a second spacer element disposed between the second lens and the third lens and in partial contact with the image side surface of the second lens, and a third spacer element disposed between the third lens and the fourth lens and in partial contact with the image side surface of the third lens; the axial distance Tr1r4 from the object side surface of the first lens to the image side surface of the second lens and the axial distance Tr5r12 from the object side surface of the third lens to the image side surface of the sixth lens satisfy: 1 < Tr1r4 / Tr5r12 < 1.2; the object side inner diameter d2s of the second spacer element and the combined focal length f12 of the first lens and the second lens satisfy: -1.25 ≤ d2s / f12 < -0.5.

[0006] According to another aspect of the present invention, there is provided an optical imaging system, comprising a lens barrel and a lens group and a spacer element group disposed in the lens barrel. The lens group is composed of six lenses. The six lenses are, in order from the object side to the image side, a first lens with a negative optical power, a second lens with a positive optical power, a third lens with a positive optical power, a fourth lens with an optical power, a fifth lens with an optical power, and a sixth lens with an optical power. Among them, the object side surface of the first lens is concave, and the image side surface is concave; the image side surface of the second lens is convex; the object side surface of the third lens is convex, and the image side surface is convex; the object side surface of the fourth lens is convex; the image side surface of the fifth lens is convex; there is an air gap between two adjacent lenses among the first lens to the sixth lens; the spacer element group includes a first spacer element disposed between the first lens and the second lens and in partial contact with the image side surface of the first lens, a second spacer element disposed between the second lens and the third lens and in partial contact with the image side surface of the second lens, and a third spacer element disposed between the third lens and the fourth lens and in partial contact with the image side surface of the third lens; the on-axis distance Tr1r4 from the object side surface of the first lens to the image side surface of the second lens and the on-axis distance Tr5r12 from the object side surface of the third lens to the image side surface of the sixth lens satisfy: 1 < Tr1r4 / Tr5r12 < 1.2; the inner diameter d0s of the object side end face of the lens barrel, the inner diameter d1s of the object side of the first spacer element, and the effective focal length f1 of the first lens satisfy: -2.8 < (d0s - d1s) / f1 < -1.8.

[0007] According to another aspect of the present invention, there is provided an optical imaging system, including a lens barrel and a lens group and a spacer element group disposed in the lens barrel. The lens group is composed of six lenses. The six lenses are, in order from the object side to the image side, a first lens with a negative optical power, a second lens with a positive optical power, a third lens with a positive optical power, a fourth lens with an optical power, a fifth lens with an optical power, and a sixth lens with an optical power. Among them, the object side surface of the first lens is concave, and the image side surface is concave; the image side surface of the second lens is convex; the object side surface of the third lens is convex, and the image side surface is convex; the object side surface of the fourth lens is convex; the image side surface of the fifth lens is convex; there is an air gap between adjacent two of the first lens to the sixth lens; the spacer element group includes a first spacer element disposed between the first lens and the second lens and in partial contact with the image side surface of the first lens, a second spacer element disposed between the second lens and the third lens and in partial contact with the image side surface of the second lens, and a third spacer element disposed between the third lens and the fourth lens and in partial contact with the image side surface of the third lens; the object side surface of the second auxiliary spacer element is in partial contact with the image side surface of the second spacer element. The center thickness CP2 of the second spacer element, the center thickness CP2b of the second auxiliary spacer element, and the sum ∑AT of the air gaps on the optical axis between adjacent two of the first lens to the sixth lens satisfy: 0.3 < (CP2 + CP2b) / ∑AT < 0.6; the outer diameter D1m on the image side of the first spacer element, the inner diameter d1m on the image side of the first spacer element, and the curvature radius R3 of the object side surface of the second lens satisfy: -3.7 < R3 / (D1m - d1m) < 16.4.

[0008] Further, the spacer element group further includes a second auxiliary spacer element disposed between the second spacer element and the third lens. The object side surface of the second auxiliary spacer element is in partial contact with the image side surface of the second spacer element. The center thickness CP2 of the second spacer element, the center thickness CP2b of the second auxiliary spacer element, and the axial distance T23 from the image side surface of the second lens to the object side surface of the third lens satisfy: 0.95 ≤ (CP2 + CP2b) / T23 ≤ 1.40.

[0009] Further, the inner diameter d1s on the object side of the first spacer element, the outer diameter D1s on the object side of the first spacer element, and the effective radius DT12 of the image side surface of the first lens satisfy: 3.2 < (D1s - d1s) / DT12 < 4.1.

[0010] Further, the inner diameter d1m on the image side of the first spacer element and the curvature radius R3 of the object side surface of the second lens satisfy: -0.15 < d1m / R3 < 0.15; the inner diameter d2s on the object side of the second spacer element and the curvature radius R4 of the image side surface of the second lens satisfy: -0.7 < d2s / R4 < -0.2.

[0011] Further, the following condition is satisfied between the image-side inner diameter d1m of the first spacer element and the object-side inner diameter d2s of the second spacer element: 0.6 < d1m / d2s < 1.

[0012] Further, the spacer element group further includes a second auxiliary spacer element disposed between the second spacer element and the third lens. The object-side surface of the second auxiliary spacer element is in partial contact with the image-side surface of the second spacer element. The following conditions are satisfied between the object-side inner diameter d2s of the second spacer element and the effective focal length f2 of the second lens: 0 < d2s / f2 < 0.55; and between the image-side inner diameter d2bm of the second auxiliary spacer element and the effective focal length f3 of the third lens: 0.35 ≤ d2bm / f3 < 1.5.

[0013] Further, the following condition is satisfied between the inner diameter d0s of the object-side end face of the lens barrel, the object-side inner diameter d1s of the first spacer element, and the effective focal length f1 of the first lens: -2.8 < (d0s - d1s) / f1 < -1.8.

[0014] Further, the following condition is satisfied between the outer diameter D0s of the object-side end face of the lens barrel, the object-side outer diameter D1s of the first spacer element, the image-side outer diameter D1m of the first spacer element, and the object-side outer diameter D2s of the second spacer element: 0.25 < (D0s - D1s) / (D1m - D2s) ≤ 1.35.

[0015] Further, the spacer element group further includes a second auxiliary spacer element disposed between the second spacer element and the third lens. The object-side surface of the second auxiliary spacer element is in partial contact with the image-side surface of the second spacer element. The following conditions are satisfied between the image-side inner diameter d2bm of the second auxiliary spacer element and the effective focal length f3 of the third lens: 0.35 ≤ d2bm / f3 < 1.5; and between the object-side inner diameter d3s of the third spacer element and the effective focal length f3 of the third lens: 0.45 ≤ d3s / f3 < 0.9.

[0016] Further, the following condition is satisfied between the effective focal length f4 of the fourth lens and the image-side inner diameter d3m of the third spacer element: -0.6 < d3m / f4 < 1.1.

[0017] Further, the following condition is satisfied between the central thickness CT2 of the second lens and the central thickness CT3 of the third lens: 1.3 < CT2 / CT3 < 2.8.

[0018] Further, the following condition is satisfied between the on-axis distance T12 from the image-side surface of the first lens to the object-side surface of the second lens, the on-axis distance T23 from the image-side surface of the second lens to the object-side surface of the third lens, and the sum ∑AT of the air spaces on the optical axis between adjacent two of the first lens to the sixth lens: 0.8 < (T12 + T23) / ∑AT ≤ 0.9.

[0019] Applying the technical solution of the present invention, the optical imaging system of the present application is composed of a lens barrel and six lenses and a plurality of spacer elements arranged in the lens barrel. By reasonably arranging the optical power and surface shape of the six lenses, a first lens with negative optical power, and a second lens with positive optical power, the absolute value of the optical power of the front-end lens is ensured to be close, which can play a complementary role and is conducive to achieving a large field of view. When the positions of the first spacer element to the third spacer element are set and the optical imaging system satisfies 1 < Tr1r4 / Tr5r12 < 1.2, this limitation makes the sum of the thicknesses of the first lens and the second lens equivalent to the sum of the thicknesses of the third lens to the sixth lens, resulting in a relatively thick thickness of the first lens and the second lens at the front end. This will cause the surface shapes of the two lenses to be relatively sensitive and will greatly affect the steepness of the light rays. The steeper the light rays, the worse the field curvature, and discrete problems are likely to occur. Therefore, in the present application, by restricting -1.25 ≤ d2s / f12 < -0.5 and controlling d2s within a reasonable range, the edges of the first two lenses are made as smooth as possible, which is conducive to improving the forming stability, reducing the surface shape sensitivity, and thus solving the discrete problem of the system. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] The accompanying drawings forming a part of this application are used to provide a further understanding of the present invention. The schematic embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation to the present invention. In the drawings:

[0021] Figure 1 The dimension marking diagram of the optical imaging system of an alternative embodiment of the present invention is shown;

[0022] Figure 2 The structural schematic diagram of the optical imaging system of Embodiment 1-1 of the present invention is shown;

[0023] Figure 3 The structural schematic diagram of the optical imaging system of Embodiment 1-2 of the present invention is shown;

[0024] Figure 4 The structural schematic diagram of the optical imaging system of Embodiment 1-3 of the present invention is shown;

[0025] Figures 5 to 7 The axial chromatic aberration curve, astigmatism curve, and distortion curve of the optical imaging system of Embodiment 1 of the present invention are respectively shown;

[0026] Figure 8 The structural schematic diagram of the optical imaging system of Embodiment 2-1 of the present invention is shown;

[0027] Figure 9 The structural schematic diagram of the optical imaging system of Embodiment 2-2 of the present invention is shown;

[0028] Figure 10Shows a schematic structural diagram of the optical imaging system according to Embodiment 2-3 of the present invention;

[0029] Figures 11 to 13 Respectively show the axial chromatic aberration curve, astigmatism curve and distortion curve of the optical imaging system according to Embodiment 2 of the present invention;

[0030] Figure 14 Shows a schematic structural diagram of the optical imaging system according to Embodiment 3-1 of the present invention;

[0031] Figure 15 Shows a schematic structural diagram of the optical imaging system according to Embodiment 3-2 of the present invention;

[0032] Figure 16 Shows a schematic structural diagram of the optical imaging system according to Embodiment 3-3 of the present invention;

[0033] Figures 17 to 19 Respectively show the axial chromatic aberration curve, astigmatism curve and distortion curve of the optical imaging system according to Embodiment 3 of the present invention;

[0034] Figure 20 Shows the MTF defocus curve diagram of the optical imaging system according to an alternative embodiment of the present invention when Tr1r4 / Tr5r12 = 1.03 and d2s / f12 = -0.72;

[0035] Figure 21 Shows the MTF defocus curve diagram of the optical imaging system according to an alternative embodiment of the present invention when Tr1r4 / Tr5r12 = 1.03 and d2s / f12 = -1.32;

[0036] Figure 22 Shows the MTF defocus curve diagram of the optical imaging system according to an alternative embodiment of the present invention when Tr1r4 / Tr5r12 = 1.03 and d2s / f12 = -0.2.

[0037] Among them, the above-mentioned drawings include the following reference numerals:

[0038] P0, lens barrel; E1, first lens; S1, object side surface of the first lens; S2, image side surface of the first lens; E2, second lens; S3, object side surface of the second lens; S4, image side surface of the second lens; E3, third lens; S5, object side surface of the third lens; S6, image side surface of the third lens; E4, fourth lens; S7, object side surface of the fourth lens; S8, image side surface of the fourth lens; E5, fifth lens; S9, object side surface of the fifth lens; S10, image side surface of the fifth lens; E6, sixth lens; S11, object side surface of the sixth lens; S12, image side surface of the sixth lens; P1, first spacer element; P2, second spacer element; P2b, second auxiliary spacer element; P3, third spacer element; P4, fourth spacer element; P5, fifth spacer element. Detailed implementation mode

[0039] It should be noted that, without conflict, the embodiments in this application and the features in the embodiments can be combined with each other. The present invention will be described in detail below with reference to the drawings and in combination with the embodiments.

[0040] It should be pointed out that, unless otherwise specified, all technical and scientific terms used in this application have the same meaning as commonly understood by those of ordinary skill in the technical field to which this application belongs.

[0041] In the present invention, unless otherwise stated, the orientation terms such as "upper, lower, top, bottom" are usually in reference to the direction shown in the drawings, or in reference to the vertical, perpendicular or gravitational direction of the component itself; similarly, for the sake of easy understanding and description, "inner, outer" refer to the inner and outer of the contour of each component itself, but the above orientation terms do not limit the present invention.

[0042] In this article, the paraxial region refers to the region near the optical axis. If the lens surface is convex and the position of the convex surface is not defined, it means that the lens surface is convex at least in the paraxial region; if the lens surface is concave and the position of the concave surface is not defined, it means that the lens surface is concave at least in the paraxial region. The judgment of the surface shape in the paraxial region can be based on the judgment method of those with ordinary knowledge in the field, and the positive and negative of the R value (R refers to the radius of curvature in the paraxial region, usually the R value on the lens database (lens data) in optical software) is used to judge the convexity and concavity. For the object side surface, when the R value is positive, it is judged as a convex surface, and when the R value is negative, it is judged as a concave surface; for the image side surface, when the R value is positive, it is judged as a concave surface, and when the R value is negative, it is judged as a convex surface. In this application, the left side is the object side and the right side is the image side.

[0043] To solve the problem that the six-piece optical imaging system in the prior art has an increased thickness of the front lens to meet a large field of view, resulting in discreteness, the present invention provides an optical imaging system. Here, it should be explained that discreteness is optical distortion, which refers to the difference in imaging quality between the edge and the center during the imaging process due to the physical characteristics and design limitations of the lens. This difference is particularly obvious in an optical imaging system with a large field of view because the marginal rays need to pass through a thicker lens, increasing the degree of light scattering and refraction, resulting in inconsistent imaging quality.

[0044] As Figures 1 to 22 shown, in an optional embodiment of the present application, the optical imaging system includes a lens barrel and a lens group and a spacer element group disposed in the lens barrel. The lens group is composed of six lenses. The six lenses are, in order from the object side to the image side, a first lens with a negative focal power, a second lens with a positive focal power, a third lens with a positive focal power, a fourth lens with a focal power, a fifth lens with a focal power, and a sixth lens with a focal power; wherein, the object side surface of the first lens is concave, and the image side surface is concave; the image side surface of the second lens is convex; the object side surface of the third lens is convex, and the image side surface is convex; the object side surface of the fourth lens is convex; the image side surface of the fifth lens is convex; there is an air gap between any two adjacent lenses among the first lens to the sixth lens; the spacer element group includes a first spacer element disposed between the first lens and the second lens and partially contacting the image side surface of the first lens, a second spacer element disposed between the second lens and the third lens and partially contacting the image side surface of the second lens, and a third spacer element disposed between the third lens and the fourth lens and partially contacting the image side surface of the third lens; the on-axis distance Tr1r4 from the object side surface of the first lens to the image side surface of the second lens and the on-axis distance Tr5r12 from the object side surface of the third lens to the image side surface of the sixth lens satisfy: 1 < Tr1r4 / Tr5r12 < 1.2; the object side inner diameter d2s of the second spacer element and the combined focal length f12 of the first lens and the second lens satisfy: -1.25 ≤ d2s / f12 < -0.5.

[0045] The optical imaging system of the present application consists of a lens barrel, six lenses and multiple spacer elements arranged in the lens barrel. By reasonably arranging the optical power and surface shape of the six lenses, the first lens with negative optical power and the second lens with positive optical power ensure that the absolute value of the optical power of the front-end lenses is close, which can play a complementary role and is beneficial to achieving a large field of view. When the positions of the first spacer element to the third spacer element are set and the optical imaging system satisfies 1 < Tr1r4 / Tr5r12 < 1.2, this limitation makes the sum of the thicknesses of the first lens and the second lens equivalent to the sum of the thicknesses of the third lens to the sixth lens, resulting in relatively thick thicknesses for the first lens and the second lens at the front end. This will cause the surface shapes of the two lenses to be relatively sensitive and will significantly affect the steepness of the light rays. The steeper the light rays, the worse the field curvature, and discrete problems are likely to occur. Therefore, in the present application, by constraining -1.25 ≤ d2s / f12 < -0.5 and controlling d2s within a reasonable range, the edges of the first two lenses are made as gentle as possible, which is beneficial to improving the forming stability and reducing the surface shape sensitivity, thereby solving the discrete problem of the system.

[0046] It should be noted that the on-axis distance Tr1r4 from the object side surface of the first lens to the image side surface of the second lens is equal to the sum of the central thickness of the first lens, the spacing distance on the optical axis between the first lens and the second lens, and the central thickness of the second lens. The on-axis distance Tr5r12 from the object side surface of the third lens to the image side surface of the sixth lens is equal to the sum of the central thickness of the third lens, the spacing distance on the optical axis between the third lens and the fourth lens, the central thickness of the fourth lens, the spacing distance on the optical axis between the fourth lens and the fifth lens, the central thickness of the fifth lens, the spacing distance on the optical axis between the fifth lens and the sixth lens, and the central thickness of the sixth lens.

[0047] In addition, referring to Table 1 below and Figures 20 to 22 as shown, on the premise that the optical imaging system satisfies Tr1r4 / Tr5r12 = 1.03, Figure 20 shows the MTF defocus curve graph when the optical imaging system satisfies d2s / f12 = -0.72, Figure 21 shows the MTF defocus curve graph when the optical imaging system satisfies d2s / f12 = -1.32, Figure 22 shows the MTF defocus curve graph when the optical imaging system satisfies d2s / f12 = -0.2.

[0048] From Figures 20 to 22It can be seen that when d2s / f12 = -0.72 is satisfied, the defocus curve is relatively concentrated and shows better performance. When d2s / f12 = -1.32 is satisfied, the discrete value is larger and the peak value drops significantly, showing poor performance. When d2s / f12 = -0.2 is satisfied, the discrete value is larger and the field curvature is negative, showing poor performance. Thus, when d2s / f12 is in the range of -1.25 to -0.5, the MTF defocus curve of the optical imaging system shows the best performance. Therefore, by constraining -1.25 ≤ d2s / f12 < -0.5 in this application, the front lens can be made as flat as possible, which is beneficial to improving the forming stability and reducing the surface sensitivity. At the same time, it can ensure a reasonable cooperation between the second spacer element and the optical powers of the front and rear lenses, which can effectively play a complementary role, is beneficial to solving the discrete problem, and ensures the imaging quality of the optical imaging system.

[0049] Table 1

[0050]

[0051] In this embodiment, the spacer element group further includes a second auxiliary spacer element disposed between the second spacer element and the third lens, and the object side surface of the second auxiliary spacer element is in partial contact with the image side surface of the second spacer element. In addition, the spacer element group further includes a fourth spacer element disposed between the fourth lens and the fifth lens and in partial contact with the image side surface of the fourth lens, and a fifth spacer element disposed between the fifth lens and the sixth lens and in partial contact with the image side surface of the fifth lens.

[0052] It should be noted that the optical imaging system of this application is an inverted structure. That is to say, each lens and each spacer element are sequentially inserted into the lens barrel from the object side end of the lens barrel, and the first lens to the sixth lens, the first spacer element, and the fifth spacer element are inserted into the lens barrel in sequence from right to left.

[0053] In this embodiment, the center thickness CP2 of the second spacer element, the center thickness CP2b of the second auxiliary spacer element, and the on-axis distance T23 from the image side surface of the second lens to the object side surface of the third lens satisfy: 0.95 ≤ (CP2 + CP2b) / T23 ≤ 1.40. By controlling the second spacer element and the second auxiliary spacer element, the total on-axis height of the optical imaging system can be effectively reduced, which helps to improve the assembly stability; at the same time, the edge thicknesses of the first lens and the second lens can be controlled to reduce internal light reflection and improve the imaging quality.

[0054] In this embodiment, the following relationship is satisfied among the object-side inner diameter d1s of the first spacer element, the object-side outer diameter D1s of the first spacer element, and the effective radius DT12 of the image side surface of the first lens: 3.2 < (D1s - d1s) / DT12 < 4.1. By controlling the relationship between the inner and outer diameters of the first spacer element and the effective radius of the image side surface of the first lens within a reasonable range, the assembly stability of the optical imaging system can be improved; at the same time, the head volume of the optical imaging system can be effectively controlled, which is beneficial to expanding the application range.

[0055] In this embodiment, the following relationship is satisfied between the image-side inner diameter d1m of the first spacer element and the curvature radius R3 of the object side surface of the second lens: -0.15 < d1m / R3 < 0.15; the following relationship is satisfied between the object-side inner diameter d2s of the second spacer element and the curvature radius R4 of the image side surface of the second lens: -0.7 < d2s / R4 < -0.2. By controlling these two conditional expressions, stray light can be effectively intercepted and the imaging quality can be improved; at the same time, controlling the size of the first spacer element can reduce the cost of the optical imaging system.

[0056] In this embodiment, the following relationship is satisfied between the image-side inner diameter d1m of the first spacer element and the object-side inner diameter d2s of the second spacer element: 0.6 < d1m / d2s < 1. By reasonably controlling the ratio of the image-side inner diameter of the first spacer element to the object-side inner diameter of the second spacer element within a reasonable range, the incident light can be in a divergent state from the first lens to the second lens, which can ensure the light transmission amount and the imaging quality; and the first spacer element and the second spacer element are attached to the edge of the chief ray, and stray light can be intercepted as much as possible without affecting the chief ray.

[0057] In this embodiment, the object side surface of the second auxiliary spacer element is in partial contact with the image side surface of the second spacer element. The following relationship is satisfied between the object-side inner diameter d2s of the second spacer element and the effective focal length f2 of the second lens: 0 < d2s / f2 < 0.55; the following relationship is satisfied between the image-side inner diameter d2bm of the second auxiliary spacer element and the effective focal length f3 of the third lens: 0.35 ≤ d2bm / f3 < 1.5. By controlling these two conditional expressions, it is beneficial to control the surface shape rationality of the second lens and the third lens, thereby improving the processing difficulty of the second lens and the third lens and ensuring the processing manufacturability.

[0058] In this embodiment, the following relationship is satisfied among the inner diameter d0s of the object side end surface of the lens barrel, the object-side inner diameter d1s of the first spacer element, and the effective focal length f1 of the first lens: -2.8 < (d0s - d1s) / f1 < -1.8. By controlling this conditional expression, it is beneficial to increase the field of view angle, increase the light transmission amount as much as possible, and improve the imaging quality; at the same time, the head size of the optical imaging system can be controlled within a reasonable range, reducing the risk of dispersion, ensuring the imaging quality, and meeting more usage scenarios.

[0059] In this embodiment, the following relationship is satisfied among the outer diameter D0s of the object-side end face of the lens barrel, the object-side outer diameter D1s of the first spacer element, the image-side outer diameter D1m of the first spacer element, and the object-side outer diameter D2s of the second spacer element: 0.25 < (D0s - D1s) / (D1m - D2s) ≤ 1.35. By controlling this relationship, the incident light can be made to diverge from the first lens to the second lens. At the same time, the first spacer element and the second spacer element can intercept stray light as much as possible, improving the imaging quality while ensuring a large field of view.

[0060] In this embodiment, the object-side surface of the second auxiliary spacer element is in partial contact with the image-side surface of the second spacer element. The following relationship is satisfied between the image-side inner diameter d2bm of the second auxiliary spacer element and the effective focal length f3 of the third lens: 0.35 ≤ d2bm / f3 < 1.5; the following relationship is satisfied between the object-side inner diameter d3s of the third spacer element and the effective focal length f3 of the third lens: 0.45 ≤ d3s / f3 < 0.9. Through these two conditional expressions, the spacer element can be made to closely adhere to the effective light rays for imaging, intercepting more stray light without affecting the passage of the effective light rays, and improving the imaging quality.

[0061] In this embodiment, the following relationship is satisfied between the effective focal length f4 of the fourth lens and the image-side inner diameter d3m of the third spacer element: -0.6 < d3m / f4 < 1.1. Through this relationship, the sizes of the third spacer element and the fourth lens can be effectively controlled, which is beneficial to reducing the size of the optical imaging system, expanding the application scenarios; at the same time, it can also reduce the cost of the optical imaging system.

[0062] In this embodiment, the following relationship is satisfied between the central thickness CT2 of the second lens and the central thickness CT3 of the third lens: 1.3 < CT2 / CT3 < 2.8. By controlling the central thicknesses of the second lens and the third lens, the total axial length of the optical imaging system can be reduced, meeting the design requirements, which is beneficial to reducing costs; at the same time, better assembly stability can be achieved.

[0063] In this embodiment, the following relationship is satisfied among the on-axis distance T12 from the image-side surface of the first lens to the object-side surface of the second lens, the on-axis distance T23 from the image-side surface of the second lens to the object-side surface of the third lens, and the sum ∑AT of the air gaps on the optical axis between any two adjacent lenses among the first lens to the sixth lens: 0.8 < (T12 + T23) / ∑AT ≤ 0.9. It should be noted that ∑AT is the sum of the air gaps on the optical axis between any two adjacent lenses among the first lens to the sixth lens. Such a setting can minimize the total axial length of the optical imaging system and reduce the overall size to meet more usage scenarios.

[0064] Optionally, the optical imaging system in the embodiments of the present application can be simulated by software and / or tools such as ZEMAX, CODEV, etc. During the simulation using the software and / or tools as described above, the surface profiles of the respective lenses can be appropriately adjusted according to the surface profiles provided by the software and / or tools used.

[0065] In addition, in another optional embodiment of the present application, an optical imaging system is further provided, which includes a lens barrel and a lens group and a spacer element group disposed in the lens barrel. The lens group is composed of six lenses. The six lenses are, in order from the object side to the image side, a first lens with a negative optical power, a second lens with a positive optical power, a third lens with a positive optical power, a fourth lens with an optical power, a fifth lens with an optical power, and a sixth lens with an optical power. Among them, the object side surface of the first lens is concave, and the image side surface is concave; the image side surface of the second lens is convex; the object side surface of the third lens is convex, and the image side surface is convex; the object side surface of the fourth lens is convex; the image side surface of the fifth lens is convex; there is an air gap between any two adjacent lenses among the first lens to the sixth lens; the spacer element group includes a first spacer element disposed between the first lens and the second lens and in partial contact with the image side surface of the first lens, a second spacer element disposed between the second lens and the third lens and in partial contact with the image side surface of the second lens, and a third spacer element disposed between the third lens and the fourth lens and in partial contact with the image side surface of the third lens; the on-axis distance Tr1r4 from the object side surface of the first lens to the image side surface of the second lens and the on-axis distance Tr5r12 from the object side surface of the third lens to the image side surface of the sixth lens satisfy: 1 < Tr1r4 / Tr5r12 < 1.2; the inner diameter d0s of the object side end face of the lens barrel, the inner diameter d1s of the object side of the first spacer element, and the effective focal length f1 of the first lens satisfy: -2.8 < (d0s - d1s) / f1 < -1.8.

[0066] The optical imaging system of the present application is composed of a lens barrel, six lenses, and multiple spacer elements disposed in the lens barrel. By reasonably arranging the optical powers and surface profiles of the six lenses, the positions of the first spacer element to the third spacer element, and setting the optical imaging system to satisfy 1 < Tr1r4 / Tr5r12 < 1.2, it is beneficial to achieve a large field of view. However, this limitation makes the sum of the thicknesses of the first lens and the second lens equivalent to the sum of the thicknesses of the third lens to the sixth lens, resulting in relatively thick thicknesses of the front-end first lens and the second lens. This will cause the surface profiles of the two lenses to be more sensitive, and the edge thicknesses are relatively thick, easily resulting in discrete problems. Therefore, by restricting -2.8 < (d0s - d1s) / f1 < -1.8, it is beneficial to increase the field of view angle, increase the light passing amount as much as possible, and improve the imaging quality; at the same time, the head size of the optical imaging system can be controlled within a reasonable range, reducing the discrete risk, ensuring the imaging quality, and meeting more usage scenarios.

[0067] Of course, other parametric expressions in the above embodiments may also be included in this embodiment, which will not be elaborated one by one here.

[0068] In addition, in another alternative embodiment of the present application, an optical imaging system is further provided, which includes a lens barrel and a lens group and a spacer element group disposed in the lens barrel. The lens group is composed of six lenses. The six lenses are, in order from the object side to the image side, a first lens with a negative optical power, a second lens with a positive optical power, a third lens with a positive optical power, a fourth lens with an optical power, a fifth lens with an optical power, and a sixth lens with an optical power; wherein, the object side surface of the first lens is concave, and the image side surface is concave; the image side surface of the second lens is convex; the object side surface of the third lens is convex, and the image side surface is convex; the object side surface of the fourth lens is convex; the image side surface of the fifth lens is convex; there is an air gap between two adjacent lenses among the first lens to the sixth lens; the spacer element group includes a first spacer element disposed between the first lens and the second lens and in partial contact with the image side surface of the first lens, a second spacer element disposed between the second lens and the third lens and in partial contact with the image side surface of the second lens, and a third spacer element disposed between the third lens and the fourth lens and in partial contact with the image side surface of the third lens; the object side surface of the second auxiliary spacer element is in partial contact with the image side surface of the second spacer element, and the center thickness CP2 of the second spacer element, the center thickness CP2b of the second auxiliary spacer element, and the sum ∑AT of the air gaps on the optical axis between two adjacent lenses among the first lens to the sixth lens satisfy: 0.3 < (CP2 + CP2b) / ∑AT < 0.6; the outer diameter D1m on the image side of the first spacer element, the inner diameter d1m on the image side of the first spacer element, and the curvature radius R3 of the object side surface of the second lens: -3.7 < R3 / (D1m - d1m) < 16.4.

[0069] The optical imaging system of the present application is composed of a lens barrel and six lenses and multiple spacer elements disposed in the lens barrel. By reasonably arranging the optical powers and surface types of the six lenses, the positions of the first spacer element to the third spacer element, and setting the optical imaging system to satisfy 0.3 < (CP2 + CP2b) / ∑AT < 0.6 and -3.7 < R3 / (D1m - d1m) < 16.4, it is beneficial to restrict the ratio of the sum of the center thickness of the second spacer element and the center thickness of the second auxiliary spacer element to the total sum ∑AT of the air gaps, beneficial to controlling the air gap and lens spacing to compress the overall size, and at the same time capable of ensuring the stable cooperation between the first spacer element and the second lens, thereby ensuring the assembly stability.

[0070] Of course, other parametric expressions in the above embodiments may also be included in this embodiment, which will not be elaborated one by one here.

[0071] Optionally, the above optical imaging system may further include a protective glass for protecting the photosensitive element located on the imaging surface.

[0072] The optical imaging system in this application may employ multiple lenses, such as the six lenses mentioned above. In this application, at least one of the mirror surfaces of each lens is an aspherical mirror surface. The characteristics of an aspherical lens are that the curvature continuously changes from the center of the lens to the periphery of the lens. Different from a spherical lens with a constant curvature from the center of the lens to the periphery, an aspherical lens has better curvature radius characteristics and has the advantages of improving distortion aberration and astigmatism aberration. After using an aspherical lens, it is possible to eliminate the aberration that appears during imaging as much as possible, thereby improving the imaging quality.

[0073] However, those skilled in the art should understand that without departing from the technical solution claimed in this application, the number of lenses constituting the optical imaging system can be changed to obtain the various results and advantages described in this specification. For example, although six lenses are described as an example in the embodiment, the optical imaging system is not limited to including six lenses. If necessary, the optical imaging system may also include other numbers of lenses.

[0074] Figure 1 A schematic diagram of the dimension marking of an optical imaging system of this application is shown. Figure 1 Parameters such as D0s, d0s, d2m, d2s, D1m, D1s, d1m, d1s, d2bm, d3s, d3m, CP2, CP2b, D2s are marked in it to clearly and intuitively understand the meaning of the parameters. For the convenience of describing the optical imaging system and the surface shape of the specific lens, these parameters will no longer be shown in the drawings when describing specific embodiments later.

[0075] The following further describes, with reference to the drawings, examples of the specific surface shape and parameters of the optical imaging system applicable to the above embodiments.

[0076] It should be noted that in the following Example 1, there are three examples of Embodiment 1-1, Embodiment 1-2, and Embodiment 1-3. In Example 2, there are three examples of Embodiment 2-1, Embodiment 2-2, and Embodiment 2-3. In Example 3, there are three examples of Embodiment 3-1, Embodiment 3-2, and Embodiment 3-3. The curvature radius, center thickness, and other parameters of the first lens to the sixth lens of the optical imaging system under the three examples in the same embodiment, as well as the spacing distance and high-order term coefficients between the lenses, are the same, but the parameters such as the thickness, inner diameter, and outer diameter of the lens barrel, the first spacer element to the third spacer element, or the first spacer element to the fifth spacer element are different. Or rather, the main structures for imaging are the same, while the auxiliary structures for imaging are different.

[0077] It should be noted that any one of the following Examples 1 to 3 is applicable to all embodiments of this application.

[0078] Example 1

[0079] As Figures 2 to 7 shown, the optical imaging system of Example 1 is described. Figure 2 The schematic structural diagram of the optical imaging system of Example 1-1 is shown, Figure 3 The schematic structural diagram of the optical imaging system of Example 1-2 is shown, Figure 4 The schematic structural diagram of the optical imaging system of Example 1-3 is shown.

[0080] As Figures 2 to 4 shown, the optical imaging system includes a lens barrel P0 and a first lens E1, a first spacer element P1, a second lens E2, a second spacer element P2, a second auxiliary spacer element P2b, a third lens E3, a third spacer element P3, a fourth lens E4, a fourth spacer element P4, a fifth lens E5, a fifth spacer element P5, and a sixth lens E6 that are sequentially arranged from the object side to the image side along the optical axis in the lens barrel P0.

[0081] As Figure 2 shown, it is the schematic structural diagram of the optical imaging system of Example 1-1. In this example, the object side surface and the image side surface of the first spacer element P1 are respectively in partial contact with the image side surface S2 of the first lens and the object side surface S3 of the second lens. The object side surface and the image side surface of the second spacer element P2 are respectively in partial contact with the image side surface S4 of the second lens and the object side surface of the second auxiliary spacer element P2b, and the image side surface of the second auxiliary spacer element P2b is in partial contact with the object side surface S5 of the third lens. The object side surface and the image side surface of the third spacer element P3 are respectively in partial contact with the image side surface S6 of the third lens and the object side surface S7 of the fourth lens. The object side surface and the image side surface of the fourth spacer element P4 are respectively in partial contact with the image side surface S8 of the fourth lens and the object side surface S9 of the fifth lens. The object side surface and the image side surface of the fifth spacer element P5 are respectively in partial contact with the image side surface S10 of the fifth lens and the object side surface S11 of the sixth lens.

[0082] As Figure 3 shown, it is the schematic structural diagram of the optical imaging system of Example 1-2. In this example, the abutting and contacting manner of each spacer element is the same as that of Example 1-1, and reference can be made to the relevant description in Example 1-1, which will not be elaborated here.

[0083] As Figure 4 shown, it is the schematic structural diagram of the optical imaging system of Example 1-3. In this example, the abutting and contacting manner of each spacer element is the same as that of Example 1-1, and reference can be made to the relevant description in Example 1-1, which will not be elaborated here.

[0084] ​​In summary, the structural parameters of the optical imaging system in the first embodiment under Embodiment 1-1, Embodiment 1-2, and Embodiment 1-3 are shown in Table 2 below. (Unit: mm)

[0085] Table 2

[0086]

[0087] In the first embodiment, the object side S1 of the first lens is concave, and the image side S2 of the first lens is concave. The object side S3 of the second lens is convex, and the image side S4 of the second lens is convex. The object side S5 of the third lens is convex, and the image side S6 of the third lens is convex. The object side S7 of the fourth lens is convex, and the image side S8 of the fourth lens is convex. The object side S9 of the fifth lens is concave, and the image side S10 of the fifth lens is convex. The object side S11 of the sixth lens is concave, and the image side S12 of the sixth lens is concave.

[0088] In the first embodiment, the effective focal length f1 of the first lens is -1.294 mm, the effective focal length f2 of the second lens is 4.131 mm, the effective focal length f3 of the third lens is 2.922 mm, the effective focal length f4 of the fourth lens is 1.297 mm, the effective focal length f5 of the fifth lens is -2.146 mm, and the effective focal length f6 of the sixth lens is -25.878 mm.

[0089] Table 3 shows the basic structural parameter table of the optical imaging system in the first embodiment, where the units of the radius of curvature and the thickness / distance are both millimeters (mm).

[0090] Table 3

[0091]

[0092] In the first embodiment, the object sides and image sides of the first lens E1 to the sixth lens E6 are all aspherical surfaces, and the surface profiles of each aspherical lens can be defined by, but are not limited to, the following aspherical formula:

[0093] Formula (1)

[0094] where x is the sagitta, the distance from the vertex of the aspherical surface to the position at a height of h along the optical axis direction of the aspherical surface; c is the paraxial curvature of the aspherical surface, c = 1 / R, that is, the paraxial curvature c is the reciprocal of the radius of curvature R in Table 1 above; k is the conic coefficient; Ai is the correction coefficient of the i-th order of the aspherical surface. Table 4 below gives the higher-order term coefficients A4, A6, A8, A10, A12, A14, A16, A18, A20, A22, A24, A26 that can be used for each aspherical mirror surface S1 - S12 in the first embodiment.

[0095] Table 4

[0096]

[0097] Figure 5 Shows the axial chromatic aberration curve of the optical imaging system of Embodiment 1, which represents the deviation of the convergence points of light rays of different wavelengths after passing through the imaging lens. Figure 6 Shows the astigmatism curve of the optical imaging system of Embodiment 1, which represents the curvature of the meridional image plane and the curvature of the sagittal image plane. Figure 7 Shows the distortion curve of the optical imaging system of Embodiment 1, which represents the distortion magnitude values corresponding to different field angles.

[0098] According to Figures 5 to 7 It can be seen that the optical imaging system given in Embodiment 1 can achieve good imaging quality.

[0099] Embodiment 2

[0100] As Figures 8 to 13 shown, the optical imaging system of Embodiment 2 is described. Figure 8 Shows a schematic structural diagram of the optical imaging system of Embodiment 2-1, Figure 9 Shows a schematic structural diagram of the optical imaging system of Embodiment 2-2, Figure 10 Shows a schematic structural diagram of the optical imaging system of Embodiment 2-3.

[0101] As Figures 8 to 10 shown, the optical imaging system includes a lens barrel P0 and a first lens E1, a first spacer element P1, a second lens E2, a second spacer element P2, a second auxiliary spacer element P2b, a third lens E3, a third spacer element P3, a fourth lens E4, a fourth spacer element P4, a fifth lens E5, a fifth spacer element P5, and a sixth lens E6 that are sequentially arranged from the object side to the image side along the optical axis in the lens barrel P0.

[0102] As Figure 8 shown, it is a schematic structural diagram of the optical imaging system of Embodiment 2-1. In this example, the object side surface and the image side surface of the first spacer element P1 are respectively in partial contact with the image side surface S2 of the first lens and the object side surface S3 of the second lens. The object side surface and the image side surface of the second spacer element P2 are respectively in partial contact with the image side surface S4 of the second lens and the object side surface of the second auxiliary spacer element P2b, and the image side surface of the second auxiliary spacer element P2b is in partial contact with the object side surface S5 of the third lens. The object side surface and the image side surface of the third spacer element P3 are respectively in partial contact with the image side surface S6 of the third lens and the object side surface S7 of the fourth lens. The object side surface and the image side surface of the fourth spacer element P4 are respectively in partial contact with the image side surface S8 of the fourth lens and the object side surface S9 of the fifth lens. The object side surface and the image side surface of the fifth spacer element P5 are respectively in partial contact with the image side surface S10 of the fifth lens and the object side surface S11 of the sixth lens.

[0103] As shown Figure 9 in the figure, it is a schematic structural diagram of the optical imaging system of Embodiment 2-2. In this example, the abutting and contacting manners of each spacer element are the same as those in Embodiment 2-1. For the relevant descriptions in Embodiment 2-1, reference can be made, and details will not be elaborated here.

[0104] As shown Figure 10 in the figure, it is a schematic structural diagram of the optical imaging system of Embodiment 2-3. In this example, the abutting and contacting manners of each spacer element are the same as those in Embodiment 2-1. For the relevant descriptions in Embodiment 2-1, reference can be made, and details will not be elaborated here.

[0105] In summary, the structural parameters of the optical imaging system in Embodiment 2 under Embodiments 2-1, 2-2, and 2-3 are shown in Table 5. (Unit: mm)

[0106] Table 5

[0107]

[0108] In Embodiment 2, the object side S1 of the first lens is concave, and the image side S2 of the first lens is concave. The object side S3 of the second lens is convex, and the image side S4 of the second lens is convex. The object side S5 of the third lens is convex, and the image side S6 of the third lens is convex. The object side S7 of the fourth lens is convex, and the image side S8 of the fourth lens is convex. The object side S9 of the fifth lens is concave, and the image side S10 of the fifth lens is convex. The object side S11 of the sixth lens is concave, and the image side S12 of the sixth lens is convex.

[0109] In Embodiment 2, the effective focal length f1 of the first lens is -1.290 mm, the effective focal length f2 of the second lens is 4.301 mm, the effective focal length f3 of the third lens is 2.986 mm, the effective focal length f4 of the fourth lens is 1.286 mm, the effective focal length f5 of the fifth lens is -1.685 mm, and the effective focal length f6 of the sixth lens is 8.022 mm.

[0110] Table 6 shows the basic structural parameter table of the optical imaging system in Embodiment 2, where the units of the radius of curvature and thickness / distance are both millimeters (mm).

[0111] Table 6

[0112]

[0113] The following Table 7 gives the higher-order term coefficients A4, A6, A8, A10, A12, A14, A16, A18, A20, A22, A24, A26 that can be used for each aspherical mirror surface S1 - S12 in Embodiment 2.

[0114] Table 7

[0115]

[0116] Figure 11 The axial chromatic aberration curve of the optical imaging system of the second embodiment is shown, which represents the deviation of the convergence points of light rays of different wavelengths after passing through the imaging lens. Figure 12 The astigmatism curve of the optical imaging system of the second embodiment is shown, which represents the curvature of the meridional image plane and the curvature of the sagittal image plane. Figure 13 The distortion curve of the optical imaging system of the second embodiment is shown, which represents the distortion magnitude values corresponding to different field angles.

[0117] According to Figures 11 to 13 it can be seen that the optical imaging system given in the second embodiment can achieve good imaging quality.

[0118] Embodiment Three

[0119] As Figures 14 to 19 shown, the optical imaging system of the third embodiment is described. Figure 14 The structural schematic diagram of the optical imaging system of Embodiment 3-1 is shown, Figure 15 The structural schematic diagram of the optical imaging system of Embodiment 3-2 is shown, Figure 16 The structural schematic diagram of the optical imaging system of Embodiment 3-3 is shown.

[0120] As Figures 14 to 16 shown, the optical imaging system includes a lens barrel P0 and a first lens E1, a first spacer element P1, a second lens E2, a second spacer element P2, a second auxiliary spacer element P2b, a third lens E3, a third spacer element P3, a fourth lens E4, a fourth spacer element P4, a fifth lens E5, a fifth spacer element P5, and a sixth lens E6 that are sequentially arranged from the object side to the image side along the optical axis in the lens barrel P0.

[0121] As Figure 14 shown, it is the structural schematic diagram of the optical imaging system of Embodiment 3-1. In this example, the object side surface and the image side surface of the first spacer element P1 are respectively in partial contact with the image side surface S2 of the first lens and the object side surface S3 of the second lens. The object side surface and the image side surface of the second spacer element P2 are respectively in partial contact with the image side surface S4 of the second lens and the object side surface of the second auxiliary spacer element P2b, and the image side surface of the second auxiliary spacer element P2b is in partial contact with the object side surface S5 of the third lens. The object side surface and the image side surface of the third spacer element P3 are respectively in partial contact with the image side surface S6 of the third lens and the object side surface S7 of the fourth lens. The object side surface and the image side surface of the fourth spacer element P4 are respectively in partial contact with the image side surface S8 of the fourth lens and the object side surface S9 of the fifth lens. The object side surface and the image side surface of the fifth spacer element P5 are respectively in partial contact with the image side surface S10 of the fifth lens and the object side surface S11 of the sixth lens.

[0122] As shown Figure 15 in the figure, it is a schematic structural diagram of the optical imaging system of Embodiment 3-2. In this example, the abutting and contacting methods of each spacer element are the same as those in Embodiment 3-1. For the relevant descriptions in Embodiment 3-1, please refer to them and will not be elaborated here.

[0123] As shown Figure 16 in the figure, it is a schematic structural diagram of the optical imaging system of Embodiment 3-3. In this example, the abutting and contacting methods of each spacer element are the same as those in Embodiment 3-1. For the relevant descriptions in Embodiment 3-1, please refer to them and will not be elaborated here.

[0124] In summary, the structural parameters of the optical imaging system in Embodiment 3 under Embodiments 3-1, 3-2, and 3-3 are shown in Table 8. (Unit: mm)

[0125] Table 8

[0126]

[0127] In Embodiment 3, the object side S1 of the first lens is concave, and the image side S2 of the first lens is concave. The object side S3 of the second lens is concave, and the image side S4 of the second lens is convex. The object side S5 of the third lens is convex, and the image side S6 of the third lens is convex. The object side S7 of the fourth lens is convex, and the image side S8 of the fourth lens is concave. The object side S9 of the fifth lens is convex, and the image side S10 of the fifth lens is convex. The object side S11 of the sixth lens is convex, and the image side S12 of the sixth lens is concave.

[0128] In Embodiment 3, the effective focal length f1 of the first lens is -1.801 mm, the effective focal length f2 of the second lens is 35.548 mm, the effective focal length f3 of the third lens is 1.889 mm, the effective focal length f4 of the fourth lens is -2.995 mm, the effective focal length f5 of the fifth lens is 1.562 mm, and the effective focal length f6 of the sixth lens is -3.726 mm.

[0129] Table 9 shows the basic structural parameter table of the optical imaging system in Embodiment 3, where the unit of the radius of curvature and the thickness / distance is millimeter (mm).

[0130] Table 9

[0131]

[0132] The following Table 10 gives the high-order term coefficients A4, A6, A8, A10, A12, A14, and A16 of the aspherical mirrors S1-S12 that can be used in Embodiment 3.

[0133] Table 10

[0134]

[0135] Figure 17 Shows the axial chromatic aberration curve of the optical imaging system of Embodiment 3, which represents the deviation of the focusing points of light rays of different wavelengths after passing through the imaging lens. Figure 18 Shows the astigmatism curve of the optical imaging system of Embodiment 3, which represents the curvature of the meridional image plane and the curvature of the sagittal image plane. Figure 19 Shows the distortion curve of the optical imaging system of Embodiment 3, which represents the distortion magnitude values corresponding to different field angles.

[0136] According to Figures 17 to 19 it can be seen that the optical imaging system given in Embodiment 3 can achieve good imaging quality.

[0137] In summary, Embodiments 1 to 3 respectively satisfy the relationships shown in Table 11.

[0138] Table 11

[0139]

[0140] Table 12 shows parameters such as the effective focal lengths of the respective lenses of the optical imaging systems of Embodiments 1 to 3 and the total effective focal length f of the optical imaging system.

[0141] Table 12

[0142]

[0143] This application also provides an imaging device, and its electronic photosensitive element can be a charge-coupled device (CCD) or a complementary metal-oxide-semiconductor element (CMOS). The imaging device can be an independent imaging device such as a digital camera, or an imaging module integrated on a mobile electronic device such as a mobile phone. The imaging device is equipped with the optical imaging system described above.

[0144] Obviously, the above-described embodiments are only some embodiments of the present invention, rather than all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without making creative efforts shall fall within the scope of protection of the present invention.

[0145] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit the exemplary embodiments according to the present application. As used herein, unless the context clearly indicates otherwise, the singular form is also intended to include the plural form. In addition, it should be understood that when the terms "comprise" and / or "include" are used in this specification, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof.

[0146] It should be noted that the terms "first", "second", etc. in the description, claims and above-mentioned drawings of this application are used to distinguish similar objects, and do not necessarily have to be used to describe a specific order or sequence. It should be understood that the data used in this way can be interchanged under appropriate circumstances so that the embodiments of this application described here can be implemented in an order other than those illustrated or described here.

[0147] The above are only the preferred embodiments of the present invention and are not used to limit the present invention. For those skilled in the art, the present invention can have various changes and modifications. Any modifications, equivalent replacements, improvements, 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 imaging system, characterized in that: It includes a lens barrel, and a lens group and a spacer element group disposed in the lens barrel. The lens group is composed of six lenses. The six lenses are, in order from the object side to the image side, a first lens with a negative focal power, a second lens with a positive focal power, a third lens with a positive focal power, a fourth lens with a focal power, a fifth lens with a focal power, and a sixth lens with a focal power. Among them, the object side surface of the first lens is concave, and the image side surface is concave; the image side surface of the second lens is convex; the object side surface of the third lens is convex, and the image side surface is convex; the object side surface of the fourth lens is convex; the image side surface of the fifth lens is convex; there is an air gap between adjacent two of the first lens to the sixth lens. The spacer element group includes a first spacer element disposed between the first lens and the second lens and in partial contact with the image side surface of the first lens, a second spacer element disposed between the second lens and the third lens and in partial contact with the image side surface of the second lens, and a third spacer element disposed between the third lens and the fourth lens and in partial contact with the image side surface of the third lens. The on-axis distance Tr1r4 from the object side surface of the first lens to the image side surface of the second lens and the on-axis distance Tr5r12 from the object side surface of the third lens to the image side surface of the sixth lens satisfy: 1 < Tr1r4 / Tr5r12 < 1.2; the object side inner diameter d2s of the second spacer element and the combined focal length f12 of the first lens and the second lens satisfy: -1.25 ≤ d2s / f12 < -0.

5.

2. The optical imaging system according to claim 1, characterized in that: The spacer element group further includes a second auxiliary spacer element disposed between the second spacer element and the third lens, and the object side surface of the second auxiliary spacer element is in partial contact with the image side surface of the second spacer element. The central thickness CP2 of the second spacer element, the central thickness CP2b of the second auxiliary spacer element, and the on-axis distance T23 from the image side surface of the second lens to the object side surface of the third lens satisfy: 0.95 ≤ (CP2 + CP2b) / T23 ≤ 1.

40.

3. The optical imaging system according to claim 1, characterized in that: The object side inner diameter d1s, the object side outer diameter D1s of the first spacer element, and the effective radius DT12 of the image side surface of the first lens satisfy: 3.2 < (D1s - d1s) / DT12 < 4.

1.

4. The optical imaging system according to claim 1, wherein the image side inner diameter d1m of the first spacer element and the curvature radius R3 of the object side surface of the second lens satisfy: -0.15 < d1m / R3 < 0.15; the object side inner diameter d2s of the second spacer element and the curvature radius R4 of the image side surface of the second lens satisfy: -0.7 < d2s / R4 < -0.

2.

5. The optical imaging system according to claim 1, characterized in that: the image side inner diameter d1m of the first spacer element and the object side inner diameter d2s of the second spacer element satisfy: 0.6 < d1m / d2s < 1.

6. The optical imaging system according to claim 1, characterized in that: The spacer element group further includes a second auxiliary spacer element disposed between the second spacer element and the third lens, wherein the object side surface of the second auxiliary spacer element is in contact with the image side surface of the second spacer element. The object side inner diameter d2s of the second spacer element and the effective focal length f2 of the second lens satisfy: <d2s / f2<0.55; The image-side inner diameter d2bm of the second auxiliary spacer element and the effective focal length f3 of the third lens satisfy the following: 0.35≤d2bm / f3<1.

5.

7. The optical imaging system according to claim 1, characterized in that: The inner diameter d0s of the object-side end surface of the lens barrel, the object-side inner diameter d1s of the first spacer element, and the effective focal length f1 of the first lens satisfy the following: -2.8<(d0s-d1s) / f1<-1.

8.

8. The optical imaging system according to claim 1, characterized in that: The outer diameter D0s of the object side end surface of the lens barrel, the object side outer diameter D1s of the first spacer element, the image side outer diameter D1m of the first spacer element and the object side outer diameter D2s of the second spacer element satisfy: 0.25<(D0s-D1s) / (D1m-D2s)≤1.

35.

9. The optical imaging system according to claim 1, characterized in that: The spacer element group further includes a second auxiliary spacer element disposed between the second spacer element and the third lens, wherein the object side surface of the second auxiliary spacer element is in contact with the image side surface of the second spacer element. The image side inner diameter d2bm of the second auxiliary spacer element and the effective focal length f3 of the third lens satisfy the following relationship: 0.35≤d2bm / f3<1.5; The object-side inner diameter d3s of the third spacing element and the effective focal length f3 of the third lens satisfy the following relationship: 0.45≤d3s / f3<0.

9.

10. The optical imaging system according to claim 1, characterized in that: The effective focal length f4 of the fourth lens and the image side inner diameter d3m of the third spacing element satisfy: -0.6 <d3m / f4<1.1。 11. The optical imaging system according to any one of claims 1 to 10, characterized in that: The center thickness CT2 of the second lens and the center thickness CT3 of the third lens satisfy: 1.3 <CT2 / CT3<2.8。 12. The optical imaging system according to any one of claims 1 to 10, characterized in that: An axial distance T12 from the image side surface of the first lens to the object side surface of the second lens, an axial distance T23 from the image side surface of the second lens to the object side surface of the third lens, and a sum ∑AT of air intervals on the optical axis between two adjacent lenses from the first lens to the sixth lens satisfy the following: 0.8<(T12+T23) / ∑AT≤0.9.

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