Optical image capturing system

Abstract

The utility model discloses an optical imaging system. The optical imaging system comprises a lens barrel, and a six-piece lens group and a spacing element group which are arranged in the lens barrel, the six-piece type lens group comprises a first lens, a second lens, a third lens, a fourth lens, a fifth lens and a sixth lens which are sequentially arranged from the object side to the image side along the optical axis; the first lens, the fourth lens and the sixth lens have negative focal power, and the second lens, the third lens and the fifth lens have positive focal power; the spacing element group comprises a fourth spacing element which is arranged on the image side surface of the fourth lens and is in contact with the image side surface of the fourth lens, and a fifth spacing element which is arranged on the image side surface of the fifth lens and is in contact with the image side surface of the fifth lens; the air interval T56 between the fifth lens and the sixth lens on the optical axis and the center thickness CT6 of the sixth lens on the optical axis meet the following conditions: 1lt; t56 / CT6lt, T56 / CT6lt; 2; the center thickness CT5 of the fifth lens on the optical axis, the maximum thickness CP4 of the fourth spacing element, and the spacing EP45 between the fourth spacing element and the fifth spacing element along the optical axis satisfy: 1.3 lt; (CT5-CP4) / EP45lt, (CT5-CP4 And 2.7.

Description

Technical Field

[0001] The present application relates to the field of optical devices, and particularly to a six-piece optical imaging system. Background Art

[0002] In recent years, with the increasing changes in consumer demands, the requirements for optical imaging systems have gradually become more complex and diverse. In different application scenarios, the performance of optical imaging systems is also different.

[0003] Currently, six-piece optical imaging systems have become mainstream. In such optical imaging systems, the sizes and relative positions of the fifth lens and the sixth lens are likely to be set unreasonably, which easily causes deformation problems of the fifth lens and the sixth lens during the assembly process, seriously affecting the imaging quality of the optical imaging system. Summary of the Utility Model

[0004] The present application provides an optical imaging system that can at least solve or partially solve at least one problem or other problems existing in the prior art.

[0005] A first aspect of the present application provides such an optical imaging system, which includes a lens barrel, a six-piece lens group and a spacer element group disposed in the lens barrel; the six-piece lens group includes a first lens, a second lens, a third lens, a fourth lens, a fifth lens and a sixth lens arranged in sequence from the object side to the image side along the optical axis; the first lens, the fourth lens and the sixth lens have negative optical powers, and the second lens, the third lens and the fifth lens have positive optical powers; the spacer element group includes a fourth spacer element disposed on the image side of the fourth lens and in contact with the image side of the fourth lens, and a fifth spacer element disposed on the image side of the fifth lens and in contact with the image side of the fifth lens; wherein, the air gap T56 between the fifth lens and the sixth lens on the optical axis and the central thickness CT6 of the sixth lens on the optical axis satisfy: 1 < T56 / CT6 < 2; the central thickness CT5 of the fifth lens on the optical axis, the maximum thickness CP4 of the fourth spacer element and the gap EP45 between the fourth spacer element and the fifth spacer element along the optical axis satisfy: 1.3 < (CT5 - CP4) / EP45 < 2.7.

[0006] According to an exemplary embodiment of the present application, the central thickness of the fifth lens on the optical axis is greater than the central thickness of any one of the lenses other than the fifth lens in the six-piece lens group on the optical axis, and the central thickness CT5 of the fifth lens on the optical axis and the gap EP45 between the fourth spacer element and the fifth spacer element along the optical axis satisfy: 1.4 < CT5 / EP45 < 2.6.

[0007] According to an exemplary embodiment of the present application, the interval EP45 between the fourth spacer element and the fifth spacer element along the optical axis, the maximum thickness CP4 of the fourth spacer element, and the maximum thickness CP5 of the fifth spacer element satisfy: 7 < EP45 / (CP4 + CP5) < 14.

[0008] According to an exemplary embodiment of the present application, the radius of curvature R11 of the object side surface of the sixth lens and the radius of curvature R12 of the image side surface of the sixth lens satisfy: -3.5 < R11 / R12 < -0.5, and the effective focal length f6 of the sixth lens, the refractive index N6 of the sixth lens, and the outer diameter D5m of the image side surface of the fifth spacer element satisfy: -4.5 < D5m / f6 × N6 < -1.5.

[0009] According to an exemplary embodiment of the present application, the central thickness CT5 of the fifth lens on the optical axis and the outer diameter D5s of the object side surface of the fifth spacer element satisfy: 3 < D5s / CT5 < 6.

[0010] According to an exemplary embodiment of the present application, the effective focal length f4 of the fourth lens, the outer diameter D4s of the object side surface of the fourth spacer element, and the inner diameter d4m of the image side surface of the fourth spacer element satisfy: -2 < (D4s - d4m) / f4 < 0.

[0011] According to an exemplary embodiment of the present application, the axial distance SAG52 between the intersection of the image side surface of the fifth lens and the optical axis and the vertex of the effective radius of the image side surface of the fifth lens, the axial distance SAG61 between the intersection of the object side surface of the sixth lens and the optical axis and the vertex of the effective radius of the object side surface of the sixth lens, and the interval EP45 between the fourth spacer element and the fifth spacer element along the optical axis satisfy: 1.2 < |SAG61 + SAG52| / EP45 < 2.4.

[0012] According to an exemplary embodiment of the present application, the spacer element group further includes a third spacer element disposed on the image side surface of the third lens and in contact with the image side surface of the third lens. Wherein, the central thickness CT4 of the fourth lens on the optical axis, the interval EP34 between the third spacer element and the fourth spacer element along the optical axis, and the interval EP45 between the fourth spacer element and the fifth spacer element along the optical axis satisfy: 3 < (EP34 + EP45) / CT4 < 6.

[0013] According to an exemplary embodiment of the present application, the spacer element group further includes a third spacer element disposed on the image side surface of the third lens and in contact with the image side surface of the third lens. Wherein, the radius of curvature R5 of the object side surface of the third lens and the radius of curvature R6 of the image side surface of the third lens satisfy: -1.8 < R6 / R5 < -0.5, and the effective focal length f3 of the third lens, the central thickness CT3 of the third lens on the optical axis, and the maximum thickness CP3 of the third spacer element satisfy: 1.5 < f3 / (CP3 + CT3)) < 3.5.

[0014] According to an exemplary embodiment of the present application, the spacer element group further includes a second spacer element disposed on the image side surface of the second lens and in contact with the image side surface of the second lens, and a third spacer element disposed on the image side surface of the third lens and in contact with the image side surface of the third lens, wherein the combined focal length f23 of the second lens and the third lens, the air interval T23 between the second lens and the third lens on the optical axis, and the interval EP23 between the second spacer element and the third spacer element along the optical axis satisfy: 2 <f23 / (EP23+T23)<4.5。

[0015] According to an exemplary embodiment of the present application, the spacer element group also includes a second spacer element placed on the image side surface of the second lens and in contact with the image side surface of the second lens, and a third spacer element placed on the image side surface of the third lens and in contact with the image side surface of the third lens, wherein an inner diameter d2s of the object side surface of the second spacer element, an outer diameter D2s of the object side surface of the second spacer element, an inner diameter d3s of the object side surface of the third spacer element, and an outer diameter D3s of the object side surface of the third spacer element satisfy: 1<(D3s-d3s) / (D2s-d2s)<3.

[0016] According to an exemplary embodiment of the present application, the spacer element group further includes a second spacer element disposed on the image side surface of the second lens and in contact with the image side surface of the second lens, and a third spacer element disposed on the image side surface of the third lens and in contact with the image side surface of the third lens, wherein the maximum thickness CP2 of the second spacer element and the maximum thickness CP3 of the third spacer element satisfy: 16 <CP2 / CP3<23。

[0017] According to an exemplary embodiment of the present application, the spacer element group further includes a first spacer element disposed on the image side surface of the first lens and in contact with the image side surface of the first lens, wherein the inner diameter d1s of the object side surface of the first spacer element satisfies the entrance pupil diameter EPD of the optical imaging system: 1.2 <d1s / EPD<1.8。

[0018] According to an exemplary embodiment of the present application, the spacer element group further includes a second spacer element disposed on the image side surface of the second lens and in contact with the image side surface of the second lens, wherein the maximum thickness of the second spacer element is greater than the maximum thickness of any spacer element in the spacer element group except the second spacer element, and the air gap T12 between the first lens and the second lens on the optical axis and the maximum thickness CP2 of the second spacer element satisfy: 1 <T12 / CP2<2.1。

[0019] According to an exemplary embodiment of the present application, the spacer element group further includes a second spacer element disposed on the image side of the second lens and in contact with the image side of the second lens, and a second auxiliary spacer element disposed on the image side of the second spacer element and in contact with the image side of the second spacer element. Wherein, the effective focal length f2 of the second lens and the outer diameter D2bs of the object side of the second auxiliary spacer element satisfy: 1.2 < f2 / D2bs < 6.8, and the effective focal length f3 of the third lens, the refractive index N3 of the third lens and the inner diameter d2bm of the image side of the second auxiliary spacer element satisfy: 1.3 < f3 / d2bm × N3 < 2.1.

[0020] According to an exemplary embodiment of the present application, half of the maximum field of view angle Semi-FOV of the optical imaging system satisfies: 60° < Semi-FOV < 68°.

[0021] The optical imaging system provided by the present application uses six lenses. By making it satisfy "1 < T56 / CT6 < 2" and "1.3 < (CT5 - CP4) / EP45 < 2.7", the intervals of the fourth spacer element and the fifth spacer element along the optical axis can be constrained within a certain range, which is beneficial to controlling the edge thickness of the fifth lens. At the same time, by cooperating with restricting the air interval between the fifth lens and the sixth lens and the central thicknesses of the fifth lens and the sixth lens, it is beneficial to controlling the overall thickness uniformity and surface profile of the fifth lens and the sixth lens, and further beneficial to the molding of the fifth lens and the sixth lens, improving the assembly stability and imaging quality of the optical imaging system. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Other features, objects and advantages of the present application will become more apparent by reading the detailed description of the non-limiting embodiments with reference to the following drawings. Among them:

[0023] Figure 1 Shows a schematic structural diagram of the optical imaging system according to the present application;

[0024] Figure 2 Shows a schematic structural diagram of the optical imaging system according to Embodiment 1 of the present application;

[0025] Figure 3 Shows a schematic structural diagram of the optical imaging system according to Embodiment 2 of the present application;

[0026] Figure 4 Shows a schematic structural diagram of the optical imaging system according to Embodiment 3 of the present application;

[0027] FIG. 5A to FIG. 5D Respectively show the axial chromatic aberration curve, astigmatism curve, distortion curve and longitudinal chromatic aberration curve of the optical imaging system according to Embodiment 1, 2 or 3 of the present application;

[0028] Figure 6 A schematic structural diagram of an optical imaging system according to Embodiment 4 of the present application is shown;

[0029] Figure 7 A schematic structural diagram of an optical imaging system according to Embodiment 5 of the present application is shown;

[0030] Figure 8 A schematic structural diagram of an optical imaging system according to Embodiment 6 of the present application is shown;

[0031] 9A to 9D The axial chromatic aberration curve, the astigmatism curve, the distortion curve and the magnification chromatic aberration curve of the optical imaging system according to Embodiment 4, 5 or 6 of the present application are respectively shown;

[0032] Fig.10 A schematic structural diagram of an optical imaging system according to Embodiment 7 of the present application is shown;

[0033] Fig.11 A schematic structural diagram of an optical imaging system according to Embodiment 8 of the present application is shown;

[0034] Fig.12 A schematic structural diagram of an optical imaging system according to Embodiment 9 of the present application is shown;

[0035] FIG. 13A to FIG. 13D The axial chromatic aberration curve, the astigmatism curve, the distortion curve and the magnification chromatic aberration curve of the optical imaging system according to Embodiment 7, 8 or 9 of the present application are respectively shown;

[0036] Fig.14A The figure shows the Modulation Transfer Function (MTF) curve when the optical imaging system satisfies the diffraction limit of T56 / CT6=1.26 and (CT5-CP4) / EP45=1.79;

[0037] Fig. 14B The modulation transfer function curve of the optical imaging system limited by the diffraction limit when T56 / CT6=1.33 and (CT5-CP4) / EP45=2.04 is shown;

[0038] Fig. 14C shows a modulation transfer function curve limited by the diffraction limit when the optical imaging system satisfies T56 / CT6=0.01, (CT5-CP4) / EP45=0.001; and

[0039] Fig.14D The modulation transfer function curve is shown when the optical imaging system satisfies the diffraction limit of T56 / CT6=12.2 and (CT5-CP4) / EP45=14. DETAILED DESCRIPTION

[0040] In order to better understand the present application, a more detailed description will be made of various aspects of the present application with reference to the accompanying drawings. It should be understood that these detailed descriptions are only descriptions of exemplary embodiments of the present application, and do not limit the scope of the present application in any way. Throughout the specification, the same figure numerals refer to the same elements.

[0041] It should be noted that in this specification, the expressions of first, second, third, etc. are only used to distinguish one feature from another feature, and do not represent any limitation on the features. Therefore, without departing from the teaching of the present application, the first lens discussed below may also be referred to as the second lens or the third lens.

[0042] In the drawings, the thickness, size and shape of the lenses have been slightly exaggerated for ease of illustration. Specifically, the shapes of the spherical or aspherical surfaces shown in the drawings are shown by way of example. That is, the shapes of the spherical or aspherical surfaces are not limited to the shapes of the spherical or aspherical surfaces shown in the drawings. The drawings are for illustration only and are not drawn strictly to scale.

[0043] 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 surface of each lens closest to the object is called the object side of the lens, and the surface of each lens closest to the imaging plane is called the image side of the lens.

[0044] It should also be understood that the terms "including" and / or "having", when used in this specification, indicate the presence of the stated features, elements and / or components, but do not exclude the presence or addition of one or more other features, elements, components and / or combinations thereof. In addition, when describing the embodiments of the present application, the term "may" is used to mean "one or more embodiments of the present application". And, the term "exemplary" is intended to refer to an example or illustration.

[0045] Unless otherwise defined, all terms (including technical terms and scientific terms) used in this article have the same meaning as those commonly understood by ordinary technicians in the field to which this application belongs. It should also be understood that terms (such as terms defined in commonly used dictionaries) should be interpreted as having the same meaning as their meaning in the context of the relevant technology, and will not be interpreted in an idealized or overly formal sense unless explicitly defined in this article.

[0046] It should be noted that, in the absence of conflict, the embodiments and features in the embodiments of the present application can be combined with each other. The present application will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

[0047] Figure 1 Schematic diagram of the structure arrangement and some parameters of the optical imaging system according to an exemplary embodiment of the present application. Figure 1 , d1s represents the inner diameter of the object side surface of the first spacing element, d2s represents the inner diameter of the object side surface of the second spacing element, D2s represents the outer diameter of the object side surface of the second spacing element, d3s represents the inner diameter of the object side surface of the third spacing element, D3s represents the outer diameter of the object side surface of the third spacing element, d4m represents the inner diameter of the image side surface of the fourth spacing element, D4s represents the outer diameter of the object side surface of the fourth spacing element, D5s represents the outer diameter of the object side surface of the fifth spacing element, D5m represents the outer diameter of the image side surface of the fifth spacing element, d2bm represents the inner diameter of the image side surface of the second auxiliary spacing element, D2bs represents the outer diameter of the object side surface of the second auxiliary spacing element, CP2 represents the maximum thickness of the second spacing element, CP3 represents the maximum thickness of the third spacing element, CP4 represents the maximum thickness of the fourth spacing element, CP5 represents the maximum thickness of the fifth spacing element, EP23 represents the interval between the second spacing element and the third spacing element along the optical axis, EP34 represents the interval between the third spacing element and the fourth spacing element along the optical axis, and EP45 represents the interval between the fourth spacing element and the fifth spacing element along the optical axis.

[0048] refer to Figures 2 to 4 , Figures 6 to 8 as well as Figures 10 to 12 In a first aspect of the present application, an optical imaging system is provided. The optical imaging system may include a six-piece lens group. The six-piece lens group may include a first lens, a second lens, a third lens, a fourth lens, a fifth lens, and a sixth lens arranged in sequence from the object side to the image side along the optical axis. Among the first lens to the sixth lens, any two adjacent lenses may have an air gap between them.

[0049] In an exemplary embodiment, the first lens may have negative optical power, with its object-side surface being convex or concave and its image-side surface being concave.

[0050] In an exemplary embodiment, the second lens may have positive refractive power, with a concave object-side surface and a convex image-side surface.

[0051] In an exemplary embodiment, the third lens may have positive refractive power, with an object-side surface being convex and an image-side surface being convex.

[0052] In example embodiments, the fourth lens may have negative power, with an object-side surface being convex or concave and an image-side surface being concave.

[0053] In example embodiments, the fifth lens may have positive refractive power, with an object-side surface being convex and an image-side surface being convex.

[0054] In an exemplary embodiment, the sixth lens may have a negative optical power, with its object side surface being concave and its image side surface being concave.

[0055] In an exemplary embodiment, the optical imaging system may further include a set of spacer elements, which may include one or more of a first spacer element, a second spacer element, a third spacer element, a fourth spacer element, a fifth spacer element, and a second auxiliary spacer element. The first spacer element may be placed on the image side surface of the first lens and at least partially in contact with the image side surface of the first lens. The second spacer element may be placed on the image side surface of the second lens and at least partially in contact with the image side surface of the second lens. The third spacer element may be placed on the image side surface of the third lens and at least partially in contact with the image side surface of the third lens. The fourth spacer element may be placed on the image side surface of the fourth lens and at least partially in contact with the image side surface of the fourth lens. The fifth spacer element may be placed on the image side surface of the fifth lens and at least partially in contact with the image side surface of the fifth lens. The second auxiliary spacer element may be placed on the image side surface of the second spacer element and at least partially in contact with the image side surface of the second spacer element. Reasonable use of the spacer elements can effectively avoid the risk of stray light, reduce the interference to the image quality, and thus improve the imaging quality of the optical imaging system.

[0056] In an exemplary embodiment, the optical imaging system may further include a lens barrel, and the six-piece lens group and the set of spacer elements are placed inside the lens barrel. The lens barrel may include an object-side end face, an image-side end face, an outer ring face, and an inner ring face. Among them, the end face of the lens barrel closest to the object side is the object-side end face of the lens barrel, and the end face of the lens barrel closest to the image side is the image-side end face of the lens barrel; in the direction perpendicular to the optical axis, the surface of the lens barrel farthest from the optical axis is the outer ring face, and the surface of the lens barrel closest to the optical axis is the inner ring face.

[0057] In an exemplary embodiment, the air gap T56 between the fifth lens and the sixth lens on the optical axis and the central thickness CT6 of the sixth lens on the optical axis may satisfy: 1 < T56 / CT6 < 2; the central thickness CT5 of the fifth lens on the optical axis, the maximum thickness CP4 of the fourth spacer element, and the gap EP45 between the fourth spacer element and the fifth spacer element along the optical axis may satisfy: 1.3 < (CT5 - CP4) / EP45 < 2.7. By making the optical imaging system satisfy "1 < T56 / CT6 < 2" and "1.3 < (CT5 - CP4) / EP45 < 2.7", the gap between the fourth spacer element and the fifth spacer element along the optical axis can be constrained within a certain range, which is beneficial to controlling the edge thickness of the fifth lens. At the same time, by cooperating with restricting the air gap between the fifth lens and the sixth lens and the central thicknesses of the fifth lens and the sixth lens, it is beneficial to controlling the overall thickness uniformity and surface profile of the fifth lens and the sixth lens, and thus beneficial to the molding of the fifth lens and the sixth lens, improving the assembly stability and imaging quality of the optical imaging system.

[0058] Fig.14AThe modulation transfer function curve limited by the diffraction limit when the optical imaging system satisfies T56 / CT6 = 1.26 and (CT5 - CP4) / EP45 = 1.79; Fig. 14B The modulation transfer function curve limited by the diffraction limit when the optical imaging system satisfies T56 / CT6 = 1.33 and (CT5 - CP4) / EP45 = 2.04; Fig. 14C The modulation transfer function curve limited by the diffraction limit when the optical imaging system satisfies T56 / CT6 = 0.01 and (CT5 - CP4) / EP45 = 0.001; Fig.14D The modulation transfer function curve limited by the diffraction limit when the optical imaging system satisfies T56 / CT6 = 12.2 and (CT5 - CP4) / EP45 = 14;

[0059] From Fig.14A and Fig. 14B it can be seen that when the optical imaging system satisfies 1 < T56 / CT6 < 2 and 1.3 < (CT5 - CP4) / EP45 < 2.7, the peak value of the MTF of the optical imaging system is at a defocus position within the range of -0.005 mm to 0.005 mm. From Fig. 14C and Fig.14D it can be seen that when the optical imaging system does not satisfy 1 < T56 / CT6 < 2 and 1.3 < (CT5 - CP4) / EP45 < 2.7, the peak value of the MTF of the optical imaging system is at a defocus position within the range of -0.01 mm to 0.01 mm. It can be seen that by controlling the optical imaging system to satisfy "1 < T56 / CT6 < 2 and 1.3 < (CT5 - CP4) / EP45 < 2.7", it helps to improve the imaging quality of the optical imaging system.

[0060] In an exemplary embodiment, the central thickness of the fifth lens on the optical axis is greater than the central thickness of any one of the lenses in the six - lens group other than the fifth lens on the optical axis, and the central thickness CT5 of the fifth lens on the optical axis and the intervals EP45 of the fourth and fifth spacer elements along the optical axis can satisfy: 1.4 < CT5 / EP45 < 2.6. By controlling the above conditional formula, the central thickness and edge thickness of the fifth lens can be constrained within a reasonable range, improving the overall structural symmetry of the fifth lens, which is beneficial to lens mold processing and lens injection molding, and reducing the AS risk.

[0061] In an exemplary embodiment, the spacing EP45 between the fourth spacer element and the fifth spacer element along the optical axis, the maximum thickness CP4 of the fourth spacer element, and the maximum thickness CP5 of the fifth spacer element may satisfy: 7 < EP45 / (CP4 + CP5) < 14. By controlling the above conditional expression, the edge thickness of the fifth lens and the thicknesses of the fourth spacer element and the fifth spacer element can be constrained within a reasonable range, avoiding problems such as easy generation of stray light caused by too large a thickness of the spacer element or difficulty in machining and forming caused by too small a thickness.

[0062] In an exemplary embodiment, the radius of curvature R11 of the object side surface of the sixth lens and the radius of curvature R12 of the image side surface of the sixth lens may satisfy: -3.5 < R11 / R12 < -0.5, and the effective focal length f6 of the sixth lens, the refractive index N6 of the sixth lens, and the outer diameter D5m of the image side surface of the fifth spacer element may satisfy: -4.5 < D5m / f6 × N6 < -1.5. By controlling the above conditional expressions, the ratio of the radius of curvature of the object side surface and the image side surface of the sixth lens can be constrained within a reasonable range. At the same time, with a reasonable effective focal length and refractive index of the sixth lens, the light can be refracted by the sixth lens and converge on the Gaussian image plane, reducing the influence of spherical aberration on the imaging quality of the optical imaging system and improving the optical performance of the optical imaging system.

[0063] In an exemplary embodiment, the central thickness CT5 of the fifth lens on the optical axis and the outer diameter D5s of the object side surface of the fifth spacer element may satisfy: 3 < D5s / CT5 < 6. By constraining the outer diameter of the object side surface of the fifth spacer element and the central thickness of the fifth lens on the optical axis within a reasonable range, the overall shape and external dimensions of the fifth lens can be effectively constrained, avoiding problems caused by insufficient dimensions in the design of the suction nozzle, coating plate, etc. of the mechanism part (i.e., the non-effective diameter part) of the fifth lens.

[0064] In an exemplary embodiment, the effective focal length f4 of the fourth lens, the outer diameter D4s of the object side surface of the fourth spacer element, and the inner diameter d4m of the image side surface of the fourth spacer element may satisfy: -2 < (D4s - d4m) / f4 < 0. By constraining the ratio of the difference between the outer diameter of the object side surface and the inner diameter of the image side surface of the fourth spacer element to the effective focal length of the fourth lens within a reasonable range, the overall shape of the fourth lens can be constrained, which is beneficial to the machining and forming of the fourth lens. At the same time, the outer diameter of the object side surface and the inner diameter of the image side surface of the fourth spacer element can also be constrained. While effectively controlling the structural dimension step difference between the fourth lens and the fifth lens and improving the assembly stability of the fourth lens and the fifth lens, the fourth spacer element is used to block the ineffective light rays at the edge of the effective diameter of the fourth lens, reducing the stray light risk of the optical imaging system.

[0065] In an exemplary embodiment, the axial distance SAG52 between the intersection point of the image side surface of the fifth lens and the optical axis and the vertex of the effective radius of the image side surface of the fifth lens, the axial distance SAG61 between the intersection point of the object side surface of the sixth lens and the optical axis and the vertex of the effective radius of the object side surface of the sixth lens, and the interval EP45 between the fourth spacer element and the fifth spacer element along the optical axis may satisfy: 1.2 < |SAG61 + SAG52| / EP45 < 2.4. By controlling the above conditional expression, the gap between the optical surface edges of the fifth lens and the sixth lens and the direction of the marginal effective rays can be constrained, which is beneficial to the placement of the spacer element between the fifth lens and the sixth lens and reduces the stray light risk of the optical imaging system.

[0066] In an exemplary embodiment, the central thickness CT4 of the fourth lens on the optical axis, the interval EP34 between the third spacer element and the fourth spacer element along the optical axis, and the interval EP45 between the fourth spacer element and the fifth spacer element along the optical axis may satisfy: 3 < (EP34 + EP45) / CT4 < 6. By controlling the above conditional expression, the interval between the third spacer element and the fourth spacer element along the optical axis and the interval between the fourth spacer element and the fifth spacer element along the optical axis can be respectively restricted within a certain range, which is beneficial to constraining the edge thicknesses of the fourth lens and the fifth lens and improving the processing formability of the fourth lens and the fifth lens; at the same time, the central thickness of the fourth lens can also be restricted within a certain range, which is beneficial to constraining the thickness ratio of the fourth lens, reducing the formed appearance weld line and stray light risk, and improving the appearance and imaging quality.

[0067] In an exemplary embodiment, the radius of curvature R5 of the object side surface of the third lens and the radius of curvature R6 of the image side surface of the third lens may satisfy: -1.8 < R6 / R5 < -0.5, and the effective focal length f3 of the third lens, the central thickness CT3 of the third lens on the optical axis, and the maximum thickness CP3 of the third spacer element may satisfy: 1.5 < f3 / (CP3 + CT3)) < 3.5. By controlling the ratio of the radius of curvature of the image side surface and the object side surface of the third lens, the problem of poor imaging caused by spherical aberration can be improved; at the same time, by matching a reasonable ratio of the effective focal length of the third lens to the sum of the thicknesses of the third spacer element and the third lens, the surface shape and structural dimensions of the third lens can be constrained, which is beneficial to the processing formability of the third lens.

[0068] In an exemplary embodiment, the combined focal length f23 of the second lens and the third lens, the air gap T23 between the second lens and the third lens on the optical axis, and the gap EP23 between the second spacer element and the third spacer element along the optical axis may satisfy: 2 < f23 / (EP23 + T23) < 4.5. By controlling the above conditional expression, the combined focal length of the second lens and the third lens can be constrained within a certain range, which is beneficial to restricting the trend and direction of light rays between the second lens and the third lens and reducing the sensitivity of the lens. At the same time, the air gap between the second lens and the third lens on the optical axis and the gap between the second spacer element and the third spacer element along the optical axis can also be constrained within a certain range, which is beneficial to restricting the shapes of the second lens and the third lens, improving the processability of the second lens and the third lens during processing, and enhancing the assembly stability and imaging quality of the optical imaging system.

[0069] In an exemplary embodiment, the inner diameter d2s of the object side surface of the second spacer element, the outer diameter D2s of the object side surface of the second spacer element, the inner diameter d3s of the object side surface of the third spacer element, and the outer diameter D3s of the object side surface of the third spacer element may satisfy: 1 < (D3s - d3s) / (D2s - d2s) < 3. By controlling the above conditional expression, the inner and outer diameters of the object side surface of the third spacer element can be restricted within a reasonable range, which is beneficial to constraining the bearing position and size between the third spacer element and the third lens and improving the assembly force stability. At the same time, the inner and outer diameters of the object side surface of the second spacer element can also be restricted within a reasonable range, effectively constraining the misalignment amount of the bearing between the second lens and the third lens and reducing the risk of deformation of the third lens caused by excessive assembly step difference between the second lens and the third lens.

[0070] In an exemplary embodiment, the inner diameter d1s of the object side surface of the first spacer element and the entrance pupil diameter EPD of the optical imaging system may satisfy: 1.2 < d1s / EPD < 1.8. By controlling the ratio of the inner diameter of the object side surface of the first spacer element to the entrance pupil diameter of the optical imaging system, it is beneficial to adjust the light passing amount of light rays entering the third lens and reduce the stray light generated after the light rays pass through the third lens. At the same time, the first spacer element can also effectively intercept the invalid light rays at the edge of the optical imaging system, reduce the risk of stray light generated by the reflection of the invalid light rays in the lens group, and avoid blocking the effective light rays, thereby enhancing the illuminance and picture quality of the optical imaging system.

[0071] In an exemplary embodiment, the maximum thickness of the second spacer element is greater than the maximum thickness of any one of the spacer elements other than the second spacer element in the spacer element group, and the air gap T12 between the first lens and the second lens on the optical axis and the maximum thickness CP2 of the second spacer element may satisfy: 1 < T12 / CP2 < 2.1. By making the second spacer element have a larger thickness, it is beneficial to thin the mechanical parts (i.e., non-effective diameter parts) of the second lens and the third lens, and is more conducive to the processing and forming of the second lens and the third lens; at the same time, the air gap between the first lens and the second lens is larger. By controlling the ratio of this air gap to the maximum thickness of the second spacer element, it is beneficial to constrain the thickness of the second spacer element within a reasonable range, and on the basis of making the second spacer element meet the processability requirements, improve the assembly stability of the optical imaging system.

[0072] In an exemplary embodiment, the effective focal length f2 of the second lens and the outer diameter D2bs of the object side surface of the second auxiliary spacer element may satisfy: 1.2 < f2 / D2bs < 6.8, and the effective focal length f3 of the third lens, the refractive index N3 of the third lens and the inner diameter d2bm of the image side surface of the second auxiliary spacer element may satisfy: 1.3 < f3 / d2bm × N3 < 2.1. By controlling the above conditional expressions, the effective focal lengths of the second lens and the third lens and the refractive index of the third lens can be constrained, the overall structures of the second lens and the third lens can be effectively controlled, and the trend of the effective light rays can be constrained, which is beneficial to the main value parameters of the system; at the same time, the outer diameter of the object side surface and the inner diameter of the image side surface of the second auxiliary spacer element can also be constrained, and the second auxiliary spacer element is used to block the marginal ineffective light rays and the structural reflected stray light rays between the second lens and the third lens, reducing the risk of stray light rays entering the third lens, and under the action of the second auxiliary spacer element, it is beneficial to reduce the inner hole size of the second spacer element, further reduce the stray light reflection of the inner hole inclined surface of the second spacer element, and improve the imaging quality of the optical imaging system.

[0073] In an exemplary embodiment, half of the maximum field of view angle Semi-FOV of the optical imaging system may satisfy: 60° < Semi-FOV < 68°. By constraining half of the maximum field of view angle of the optical imaging system within the range of 60° to 68°, the aperture size of the optical imaging system can be controlled, and the light input of the optical imaging system can be ensured.

[0074] In an exemplary embodiment, the maximum thickness CP2 of the second spacer element and the maximum thickness CP3 of the third spacer element may satisfy: 16 < CP2 / CP3 < 23. By controlling the above conditional expression, the thicknesses of the second spacer element and the third spacer element can be constrained within a reasonable range, avoiding the problems of easy generation of stray light caused by too large a thickness of the spacer element or difficult processing and forming caused by too small a thickness.

[0075] In an exemplary embodiment, the optical imaging system further includes a stop disposed between the second lens and the third lens.

[0076] According to the above-mentioned embodiment of the present application, the optical imaging system can use six lenses and at least one spacer element. By reasonably allocating the parameters of each lens and each spacer element, the risk of stray light in the optical imaging system can be reduced, and the processability, assembly stability and imaging quality of the optical imaging system can be improved.

[0077] In an embodiment of the present application, at least one of the surfaces of each lens in the first lens to the sixth lens is an aspherical surface. The characteristic of an aspherical lens is that the curvature changes continuously from the center of the lens to the periphery of the lens. Unlike a spherical lens having a constant curvature from the center of the lens to the periphery of the lens, an aspherical lens has a better curvature radius characteristic, and has the advantages of improving distortion aberration and improving astigmatism aberration. After adopting an aspherical lens, the aberration that occurs during imaging can be eliminated as much as possible, thereby improving the imaging quality. Optionally, the object side surface and the image side surface of each lens in the second lens to the sixth lens are both aspherical surfaces.

[0078] The second aspect of the present application provides an optical imaging system, which includes a lens barrel and a six-piece lens group and a spacer element group placed in the lens barrel. The six-piece lens group includes a first lens, a second lens, a third lens, a fourth lens, a fifth lens and a sixth lens arranged in sequence from the object side to the image side along the optical axis; the first lens, the fourth lens and the sixth lens have negative optical power, and the second lens, the third lens and the fifth lens have positive optical power. The spacer element group includes a second spacer element placed on the image side of the second lens and in contact with the image side of the second lens, and a third spacer element placed on the image side of the third lens and in contact with the image side of the third lens.

[0079] Among them, half of the maximum field of view angle of the optical imaging system, Semi-FOV, satisfies: 60° < Semi-FOV < 68°; the maximum thickness CP2 of the second spacer element and the maximum thickness CP3 of the third spacer element satisfy: 16 < CP2 / CP3 < 23; the combined focal length f23 of the second lens and the third lens, the air gap T23 between the second lens and the third lens on the optical axis, and the gap EP23 between the second spacer element and the third spacer element along the optical axis satisfy: 2 < f23 / (EP23 + T23) < 4.5. By making the optical imaging system satisfy "60° < Semi-FOV < 68°", the aperture size of the optical imaging system can be controlled, and the light input amount of the optical imaging system can be ensured. At the same time, by controlling the optical imaging system to satisfy "16 < CP2 / CP3 < 23" and "2 < f23 / (EP23 + T23) < 4.5", the combined focal length of the second lens and the third lens can be constrained within a certain range, which is beneficial to controlling the trend and direction of light rays between the second lens and the third lens, reducing the sensitivity of the lens, and more beneficial to controlling the overall external dimension of the optical imaging system; it can also constrain the air gap between the second lens and the third lens on the optical axis and the gap between the second spacer element and the third spacer element along the optical axis within a certain range, which is beneficial to controlling the shapes of the second lens and the third lens, improving the processing formability of the second lens and the third lens, and enhancing the assembly stability and imaging quality of the optical imaging system.

[0080] Those skilled in the art should understand that without departing from the technical solutions claimed in this application, the number of lenses and spacer elements constituting the optical imaging system can be changed to obtain the various results and advantages described in this specification.

[0081] The following further describes specific embodiments of the optical imaging system applicable to the above embodiments with reference to the accompanying drawings.

[0082] Example 1

[0083] The following refers to Figure 2 Describe the optical imaging system according to Embodiment 1 of this application.

[0084] As Figure 2As shown, the optical imaging system includes a lens barrel and a six-piece lens group and a spacer element group placed in the lens barrel. The six-piece lens group includes: a first lens E1, a second lens E2, a third lens E3, a fourth lens E4, a fifth lens E5 and a sixth lens E6 in order from the object side to the image side along the optical axis. The aperture STO can be arranged between the second lens E2 and the third lens E3. The spacer element group includes a first spacer element P1, a second spacer element P2, a third spacer element P3, a fourth spacer element P4 and a fifth spacer element P5. The spacer element group also includes a second auxiliary spacer element P2b. The spacer element can block the excess light in the imaging process from entering the next lens, and at the same time make the lens and the lens barrel better supported, thereby enhancing the structural stability of the optical imaging system.

[0085] The first lens E1 has negative optical power, and its object side surface S1 is concave, and its image side surface S2 is concave. The second lens E2 has positive optical power, and its object side surface S3 is concave, and its image side surface S4 is convex. The third lens E3 has positive optical power, and its object side surface S5 is convex, and its image side surface S6 is convex. The fourth lens E4 has negative optical power, and its object side surface S7 is convex, and its image side surface S8 is concave. The fifth lens E5 has positive optical power, and its object side surface S9 is convex, and its image side surface S10 is convex. The sixth lens E6 has negative optical power, and its object side surface S11 is concave, and its image side surface S12 is concave. The filter has an object side surface S13 (not shown) and an image side surface S14 (not shown). The light from the object passes through each surface S1 to S14 in sequence and is finally imaged on the imaging surface S15 (not shown).

[0086] Table 1 shows a basic parameter table of the optical imaging system of Example 1, wherein the units of the radius of curvature, thickness / distance, and focal length are all millimeters (mm).

[0087]

[0088]

[0089] Table 1

[0090] In this embodiment, the object side surface and the image side surface of any lens among the first lens E1 to the sixth lens E6 are both aspherical surfaces, and the surface shape x of each aspherical lens can be defined by but not limited to the following aspherical surface formula:

[0091]

[0092] Wherein, x is the distance vector height from the vertex of the aspheric surface when the aspheric surface is at a height of h along the optical axis; c is the paraxial curvature of the aspheric surface, c=1 / R (i.e., the paraxial curvature c is the reciprocal of the curvature radius R in Table 1 above); k is the cone coefficient; Ai is the correction coefficient of the i-th order of the aspheric surface. Table 2 shows the high-order coefficients A4, A6, A8, A9, A10, A11, A12, A13, A14, A15, A16, A17, A18, A19, A20, A21, A22, A23, A24, A25, A26, A27, A28, A29, A30, A31, A32, A33, A34, A35, A36, A37, A38, A39, A40, A41, A42, A43, A44, A45, A46, A47, A50, A51, A52, A53, A54, A55, A56, A57, A58, A59, A60, A61, A71, A72, A73, A74, A75, A76, A77, A8, A9, A10, A11, A12, A13, A14, A15 10 , A 12 , A 14 , A 16 , A 18 , A 20 , A 22 , A 24 , A 26 and A 28 .

[0093]

[0094]

[0095] Table 2

[0096] Example 2

[0097] The following reference Figure 3 Describe the optical imaging system according to Example 2 of the present application.

[0098] like Figure 3 As shown, the optical imaging system includes a lens barrel and a six-piece lens group and a spacer element group placed in the lens barrel. The six-piece lens group includes: a first lens E1, a second lens E2, a third lens E3, a fourth lens E4, a fifth lens E5 and a sixth lens E6 in order from the object side to the image side along the optical axis. The aperture STO can be arranged between the second lens E2 and the third lens E3. The spacer element group includes a first spacer element P1, a second spacer element P2, a third spacer element P3, a fourth spacer element P4 and a fifth spacer element P5. The spacer element group also includes a second auxiliary spacer element P2b. The spacer element can block the excess light in the imaging process from entering the next lens, and at the same time make the lens and the lens barrel better supported, thereby enhancing the structural stability of the optical imaging system.

[0099] The structure of the lens of this embodiment is the same as that of the lens of embodiment 1, that is, the basic parameter table of the optical imaging system of this embodiment is the same as Table 1, and the aspheric coefficient table is the same as Table 2. The difference between this embodiment and embodiment 1 is that the structural dimensions of the first spacing element P1, the second spacing element P2, the third spacing element P3, the fourth spacing element P4, the fifth spacing element P5 and the second auxiliary spacing element P2b are different. For example, the parameters such as d1s, d2s, D2s, d3s, D3s, d4m, D4s, D5s, D5m, d2bm, D2bs, CP2, CP3, CP4, CP5, EP23, EP34, EP45 are different.

[0100] Example 3

[0101] The following reference Figure 4 Describe the optical imaging system according to Example 3 of the present application.

[0102] like Figure 4 As shown, the optical imaging system includes a lens barrel and a six-piece lens group and a spacer element group placed in the lens barrel. The six-piece lens group includes: a first lens E1, a second lens E2, a third lens E3, a fourth lens E4, a fifth lens E5 and a sixth lens E6 in order from the object side to the image side along the optical axis. The aperture STO can be arranged between the second lens E2 and the third lens E3. The spacer element group includes a first spacer element P1, a second spacer element P2, a third spacer element P3, a fourth spacer element P4 and a fifth spacer element P5. The spacer element group also includes a second auxiliary spacer element P2b. The spacer element can block the excess light in the imaging process from entering the next lens, and at the same time make the lens and the lens barrel better supported, thereby enhancing the structural stability of the optical imaging system.

[0103] The structure of the lens of this embodiment is the same as that of the lens of embodiment 1, that is, the basic parameter table of the optical imaging system of this embodiment is the same as Table 1, and the aspheric coefficient table is the same as Table 2. The difference between this embodiment and embodiment 1 is that the structural dimensions of the first spacing element P1, the second spacing element P2, the third spacing element P3, the fourth spacing element P4, the fifth spacing element P5 and the second auxiliary spacing element P2b are different. For example, the parameters such as d1s, d2s, D2s, d3s, D3s, d4m, D4s, D5s, D5m, d2bm, D2bs, CP2, CP3, CP4, CP5, EP23, EP34, EP45 are different.

[0104] Figure 5A The axial chromatic aberration curves of the optical imaging systems of Examples 1, 2, and 3 are shown, which indicate the deviation of the focal point of light of different wavelengths after passing through the optical imaging system. Figure 5BAstigmatism curves of the optical imaging systems of Examples 1, 2, and 3 are shown, which represent the meridional image plane curvature and sagittal image plane curvature corresponding to different field angles. Figure 5C The distortion curves of the optical imaging systems of Examples 1, 2, and 3 are shown, which represent the distortion magnitude values ​​corresponding to different field angles. Figure 5D The magnification chromatic aberration curves of the optical imaging systems of Examples 1, 2, and 3 are shown, which represent the deviations of different image heights on the imaging surface after the light passes through the system. FIG. 5A to FIG. 5D It can be seen that the optical imaging systems provided in Examples 1, 2, and 3 can achieve good imaging quality.

[0105] Example 4

[0106] The following reference Figure 6 Describe the optical imaging system according to Example 4 of the present application.

[0107] like Figure 6 As shown, the optical imaging system includes a lens barrel and a six-piece lens group and a spacer element group placed in the lens barrel. The six-piece lens group includes: a first lens E1, a second lens E2, a third lens E3, a fourth lens E4, a fifth lens E5 and a sixth lens E6 in order from the object side to the image side along the optical axis. The aperture STO can be arranged between the second lens E2 and the third lens E3. The spacer element group includes a first spacer element P1, a second spacer element P2, a third spacer element P3, a fourth spacer element P4 and a fifth spacer element P5. The spacer element group also includes a second auxiliary spacer element P2b. The spacer element can block the excess light in the imaging process from entering the next lens, and at the same time make the lens and the lens barrel better supported, thereby enhancing the structural stability of the optical imaging system.

[0108] The first lens E1 has negative optical power, and its object side surface S1 is convex, and its image side surface S2 is concave. The second lens E2 has positive optical power, and its object side surface S3 is concave, and its image side surface S4 is convex. The third lens E3 has positive optical power, and its object side surface S5 is convex, and its image side surface S6 is convex. The fourth lens E4 has negative optical power, and its object side surface S7 is concave, and its image side surface S8 is concave. The fifth lens E5 has positive optical power, and its object side surface S9 is convex, and its image side surface S10 is convex. The sixth lens E6 has negative optical power, and its object side surface S11 is concave, and its image side surface S12 is concave. The filter has an object side surface S13 (not shown) and an image side surface S14 (not shown). The light from the object passes through each surface S1 to S14 in sequence and is finally imaged on the imaging surface S15 (not shown).

[0109] Table 3 shows a basic parameter table of the optical imaging system of Example 4, wherein the units of the radius of curvature, thickness / distance, and focal length are all millimeters (mm).

[0110]

[0111]

[0112] Table 3

[0113] In this embodiment, the object side surface and the image side surface of any lens from the first lens E1 to the sixth lens E6 are both aspherical surfaces. Table 4 lists the high-order coefficients A4, A6, A8, A9, A10, A11, A12, A13, A14, A15, A16, A17, A18, A19, A20, A21, A22, A23, A24, A25, A26, A27, A28, A29, A30, A31, A32, A33, A34, A35, A36, A37, A38, A39, A40, A41, A42, A43, A44, A45, A46, A47, A48, A49, A50, A51, A52, A53, A54, A55, A56, A57, A58, A59, A60, A61, A62, A63, A70, A71, A72, A73, A74, A75 10 , A 12 , A 14 , A 16 , A 18 , A 20 , A 22 , A 24 , A 26 and A 28 .

[0114]

[0115] Table 4

[0116] Example 5

[0117] The following reference Figure 7 Describe the optical imaging system according to Example 5 of the present application.

[0118] like Figure 7 As shown, the optical imaging system includes a lens barrel and a six-piece lens group and a spacer element group placed in the lens barrel. The six-piece lens group includes: a first lens E1, a second lens E2, a third lens E3, a fourth lens E4, a fifth lens E5 and a sixth lens E6 in order from the object side to the image side along the optical axis. The aperture STO can be arranged between the second lens E2 and the third lens E3. The spacer element group includes a first spacer element P1, a second spacer element P2, a third spacer element P3, a fourth spacer element P4 and a fifth spacer element P5. The spacer element group also includes a second auxiliary spacer element P2b. The spacer element can block the excess light in the imaging process from entering the next lens, and at the same time make the lens and the lens barrel better supported, thereby enhancing the structural stability of the optical imaging system.

[0119] The structure of the lens of this embodiment is the same as that of the lens of embodiment 4, that is, the basic parameter table of the optical imaging system of this embodiment is the same as Table 3, and the aspheric coefficient table is the same as Table 4. The difference between this embodiment and embodiment 4 is that the structural dimensions of the first spacing element P1, the second spacing element P2, the third spacing element P3, the fourth spacing element P4, the fifth spacing element P5 and the second auxiliary spacing element P2b are different. For example, the parameters such as d1s, d2s, D2s, d3s, D3s, d4m, D4s, D5s, D5m, d2bm, D2bs, CP2, CP3, CP4, CP5, EP23, EP34, EP45 are different.

[0120] Example 6

[0121] The following reference Figure 8 Describe the optical imaging system according to Example 6 of the present application.

[0122] like Figure 8 As shown, the optical imaging system includes a lens barrel and a six-piece lens group and a spacer element group placed in the lens barrel. The six-piece lens group includes: a first lens E1, a second lens E2, a third lens E3, a fourth lens E4, a fifth lens E5 and a sixth lens E6 in order from the object side to the image side along the optical axis. The aperture STO can be arranged between the second lens E2 and the third lens E3. The spacer element group includes a first spacer element P1, a second spacer element P2, a third spacer element P3, a fourth spacer element P4 and a fifth spacer element P5. The spacer element group also includes a second auxiliary spacer element P2b. The spacer element can block the excess light in the imaging process from entering the next lens, and at the same time make the lens and the lens barrel better supported, thereby enhancing the structural stability of the optical imaging system.

[0123] The structure of the lens of this embodiment is the same as that of the lens of embodiment 4, that is, the basic parameter table of the optical imaging system of this embodiment is the same as Table 3, and the aspheric coefficient table is the same as Table 4. The difference between this embodiment and embodiment 4 is that the structural dimensions of the first spacing element P1, the second spacing element P2, the third spacing element P3, the fourth spacing element P4, the fifth spacing element P5 and the second auxiliary spacing element P2b are different. For example, the parameters such as d1s, d2s, D2s, d3s, D3s, d4m, D4s, D5s, D5m, d2bm, D2bs, CP2, CP3, CP4, CP5, EP23, EP34, EP45 are different.

[0124] Fig.9A The axial chromatic aberration curves of the optical imaging systems of Examples 4, 5, and 6 are shown, which indicate the deviation of the focal point of light of different wavelengths after passing through the optical imaging system. Fig. 9BAstigmatism curves of the optical imaging systems of Examples 4, 5, and 6 are shown, which represent the meridional image plane curvature and sagittal image plane curvature corresponding to different field angles. Fig. 9C The distortion curves of the optical imaging systems of Examples 4, 5, and 6 are shown, which represent the distortion magnitude values ​​corresponding to different field of view angles. Fig.9D The magnification chromatic aberration curves of the optical imaging systems of Examples 4, 5, and 6 are shown, which represent the deviations of different image heights on the imaging surface after the light passes through the system. 9A to 9D It can be seen that the optical imaging systems provided in Examples 4, 5 and 6 can achieve good imaging quality.

[0125] Example 7

[0126] The following reference Fig.10 Describe the optical imaging system according to Example 7 of the present application.

[0127] like Fig.10 As shown, the optical imaging system includes a lens barrel and a six-piece lens group and a spacer element group placed in the lens barrel. The six-piece lens group includes: a first lens E1, a second lens E2, a third lens E3, a fourth lens E4, a fifth lens E5 and a sixth lens E6 in order from the object side to the image side along the optical axis. The aperture STO can be arranged between the second lens E2 and the third lens E3. The spacer element group includes a first spacer element P1, a second spacer element P2, a third spacer element P3, a fourth spacer element P4 and a fifth spacer element P5. The spacer element group also includes a second auxiliary spacer element P2b. The spacer element can block the excess light in the imaging process from entering the next lens, and at the same time make the lens and the lens barrel better supported, thereby enhancing the structural stability of the optical imaging system.

[0128] The first lens E1 has negative optical power, and its object side surface S1 is convex, and its image side surface S2 is concave. The second lens E2 has positive optical power, and its object side surface S3 is concave, and its image side surface S4 is convex. The third lens E3 has positive optical power, and its object side surface S5 is convex, and its image side surface S6 is convex. The fourth lens E4 has negative optical power, and its object side surface S7 is concave, and its image side surface S8 is concave. The fifth lens E5 has positive optical power, and its object side surface S9 is convex, and its image side surface S10 is convex. The sixth lens E6 has negative optical power, and its object side surface S11 is concave, and its image side surface S12 is concave. The filter has an object side surface S13 (not shown) and an image side surface S14 (not shown). The light from the object passes through each surface S1 to S14 in sequence and is finally imaged on the imaging surface S15 (not shown).

[0129] Table 5 shows a basic parameter table of the optical imaging system of Example 7, wherein the units of the radius of curvature, thickness / distance, and focal length are all millimeters (mm).

[0130]

[0131] Table 5

[0132] In this embodiment, the object side surface and the image side surface of any lens from the first lens E1 to the sixth lens E6 are both aspherical surfaces. Table 6 lists the high-order coefficients A4, A6, A8, A9, A10, A11, A12, A13, A14, A15, A16, A17, A18, A19, A20, A21, A22, A23, A24, A25, A26, A27, A28, A29, A30, A31, A32, A33, A34, A35, A36, A37, A38, A39, A40, A41, A42, A43, A44, A45, A46, A47, A48, A49, A50, A51, A52, A53, A54, A55, A56, A57, A58, A5 10 , A 12 , A 14 , A 16 , A 18 , A 20 , A 22 , A 24 , A 26 and A 28 .

[0133]

[0134]

[0135] Table 6

[0136] Example 8

[0137] The following reference Fig.11 Describe the optical imaging system according to Example 8 of the present application.

[0138] like Fig.11 As shown, the optical imaging system includes a lens barrel and a six-piece lens group and a spacer element group placed in the lens barrel. The six-piece lens group includes: a first lens E1, a second lens E2, a third lens E3, a fourth lens E4, a fifth lens E5 and a sixth lens E6 in order from the object side to the image side along the optical axis. The aperture STO can be arranged between the second lens E2 and the third lens E3. The spacer element group includes a first spacer element P1, a second spacer element P2, a third spacer element P3, a fourth spacer element P4 and a fifth spacer element P5. The spacer element group also includes a second auxiliary spacer element P2b. The spacer element can block the excess light in the imaging process from entering the next lens, and at the same time make the lens and the lens barrel better supported, thereby enhancing the structural stability of the optical imaging system.

[0139] The structure of the lens of this embodiment is the same as that of the lens of embodiment 7, that is, the basic parameter table of the optical imaging system of this embodiment is the same as Table 5, and the aspheric coefficient table is the same as Table 6. The difference between this embodiment and embodiment 7 is that the structural dimensions of the first spacing element P1, the second spacing element P2, the third spacing element P3, the fourth spacing element P4, the fifth spacing element P5 and the second auxiliary spacing element P2b are different. For example, the parameters such as d1s, d2s, D2s, d3s, D3s, d4m, D4s, D5s, D5m, d2bm, D2bs, CP2, CP3, CP4, CP5, EP23, EP34, EP45 are different.

[0140] Example 9

[0141] The following reference Fig.12 Describe the optical imaging system according to Example 9 of the present application.

[0142] like Fig.12 As shown, the optical imaging system includes a lens barrel and a six-piece lens group and a spacer element group placed in the lens barrel. The six-piece lens group includes: a first lens E1, a second lens E2, a third lens E3, a fourth lens E4, a fifth lens E5 and a sixth lens E6 in order from the object side to the image side along the optical axis. The aperture STO can be arranged between the second lens E2 and the third lens E3. The spacer element group includes a first spacer element P1, a second spacer element P2, a third spacer element P3, a fourth spacer element P4 and a fifth spacer element P5. The spacer element group also includes a second auxiliary spacer element P2b. The spacer element can block the excess light in the imaging process from entering the next lens, and at the same time make the lens and the lens barrel better supported, thereby enhancing the structural stability of the optical imaging system.

[0143] The structure of the lens of this embodiment is the same as that of the lens of embodiment 7, that is, the basic parameter table of the optical imaging system of this embodiment is the same as Table 5, and the aspheric coefficient table is the same as Table 6. The difference between this embodiment and embodiment 7 is that the structural dimensions of the first spacing element P1, the second spacing element P2, the third spacing element P3, the fourth spacing element P4, the fifth spacing element P5 and the second auxiliary spacing element P2b are different. For example, the parameters such as d1s, d2s, D2s, d3s, D3s, d4m, D4s, D5s, D5m, d2bm, D2bs, CP2, CP3, CP4, CP5, EP23, EP34, EP45 are different.

[0144] Fig.13A The axial chromatic aberration curves of the optical imaging systems of Examples 7, 8, and 9 are shown, which indicate the deviation of the focal point of light of different wavelengths after passing through the optical imaging system. Fig. 13BAstigmatism curves of the optical imaging systems of Examples 7, 8, and 9 are shown, which represent the meridional image plane curvature and sagittal image plane curvature corresponding to different field angles. Fig. 13C The distortion curves of the optical imaging systems of Examples 7, 8 and 9 are shown, which represent the distortion magnitude values ​​corresponding to different field of view angles. Fig.13D The magnification chromatic aberration curves of the optical imaging systems of Examples 7, 8, and 9 are shown, which represent the deviations of different image heights on the imaging surface after the light passes through the system. FIG. 13A to FIG. 13D It can be seen that the optical imaging systems provided in Examples 7, 8 and 9 can achieve good imaging quality.

[0145] Table 7 shows the values ​​of parameters such as Semi-FOV, EPD, f, f23, SAG52, SAG61, etc. of each embodiment in Embodiments 1 to 9. The unit of Semi-FOV is °, and the unit of parameters other than Semi-FOV in Table 7 is mm.

[0146] Parameters / Examples 1 2 3 4 5 6 7 8 9 Semi-FOV 61.0000 61.0000 61.0000 61.0000 61.0000 61.0000 66.0000 66.0000 66.0000 EPD 1.2277 1.2277 1.2277 1.2414 1.2414 1.2414 1.2500 1.2500 1.2500 f 2.2260 2.2260 2.2260 2.2415 2.2415 2.2415 2.2574 2.2574 2.2574 f23 1.6248 1.6248 1.6248 1.6313 1.6313 1.6313 1.6211 1.6211 1.6211 SAG52 -0.2598 -0.2598 -0.2598 -0.2577 -0.2577 -0.2577 -0.2980 -0.2980 -0.2980 SAG61 -0.5481 -0.5481 -0.5481 -0.5431 -0.5431 -0.5431 -0.6018 -0.6018 -0.6018

[0147] Table 7

[0148] Table 8 shows the values ​​of parameters such as d1s, d2s, D2s, d3s, D3s, d4m, D4s, D5s, D5m, d2bm, D2bs, CP2, CP3, CP4, CP5, EP23, EP34, EP45, etc. in each embodiment of embodiments 1-9. The above parameters can be calculated according to Figure 1 The marking method shown is measured, and the units of the parameters listed in Table 8 are all mm.

[0149]

[0150]

[0151] Table 8 and Table 9 show the values ​​of the conditional expressions of each embodiment in Embodiments 1 to 9.

[0152] Conditional / Example 1 2 3 4 5 6 7 8 9 T56 / CT6 1.2553 1.2553 1.2553 1.3245 1.3245 1.3245 1.5910 1.5910 1.5910 CT5 / EP45 1.9938 2.2405 2.0947 2.0514 2.0514 2.1990 1.6299 1.6897 1.8381 (CT5-CP4) / EP45 1.9433 2.1838 2.0417 2.0022 2.0022 2.1463 1.5910 1.6494 1.7942 EP45 / (CP4+CP5) 9.9091 8.8182 9.4318 10.1591 10.1591 9.4773 12.8409 12.3864 11.3864 R11 / R12 -2.7216 -2.7216 -2.7216 -2.0821 -2.0821 -2.0821 -1.5206 -1.5206 -1.5206 D5m / f6×N6 -2.8610 -2.9343 -2.3981 -3.7666 -3.8414 -3.8713 -3.0356 -2.2899 -3.1438 D5s / CT5 4.4864 4.6014 3.7605 5.4962 5.6052 5.6489 4.5086 3.4010 4.6693 (D4s-d4m) / f4 -0.8382 -0.8885 -0.4492 -1.2832 -1.3302 -1.3184 -1.0310 -0.5332 -1.1116 (EP34+EP45) / CT4 4.3520 4.0000 4.7960 4.4520 4.4520 4.4520 4.1600 4.0733 4.0833 R6 / R5 -1.2648 -1.2648 -1.2648 -1.2323 -1.2323 -1.2323 -0.9154 -0.9154 -0.9154 f3 / (CP3+CT3) 2.5923 2.5923 2.5923 2.0509 2.0509 2.0509 2.9948 2.9948 2.9948 f23 / (EP23+T23) 2.9420 2.7904 3.6245 2.6875 2.6875 2.6875 3.3035 3.1434 3.7377 (D3s-d3s) / (D2s-d2s) 1.4092 1.4719 1.8968 2.6257 2.6118 1.4199 2.1699 1.3775 2.7174 d1s / EPD 1.6307 1.6519 1.6787 1.5732 1.5732 1.5732 1.4704 1.4704 1.4704 T12 / CP2 1.3182 1.3182 1.3182 1.6618 1.8381 1.7455 1.6315 1.7183 1.5720 f2 / D2bs 3.3776 3.2990 3.2241 6.3646 6.2331 6.1820 1.7647 1.7259 1.7079 f3 / d2bm×N3 1.6946 1.6946 1.6946 1.6266 1.6266 1.6266 1.8957 1.8957 1.8957 CP2 / CP3 21.4091 21.4091 21.4091 18.9545 17.1364 18.0455 18.0000 17.0909 18.6818 |SAG61+SAG52| / EP45 1.8529 2.0821 1.9466 1.7916 1.7916 1.9205 1.5927 1.6511 1.7961

[0153] Table 9

[0154] The present application also provides an imaging device, whose electronic photosensitive element can be a photosensitive coupled device (CCD) or a complementary metal oxide semiconductor device (CMOS). The imaging device can be an independent imaging device such as a digital camera, or an imaging module integrated in a mobile electronic device such as a mobile phone, or a projection device. The imaging device is equipped with the optical imaging system described above.

[0155] The above description is only a preferred embodiment of the present application and an explanation of the technical principles used. Those skilled in the art should understand that the scope of the utility model involved in the present application is not limited to the technical solution formed by a specific combination of the above technical features, but should also cover other technical solutions formed by any combination of the above technical features or their equivalent features without departing from the inventive concept. For example, the above features are replaced with the technical features with similar functions disclosed in the present application (but not limited to) by each other.

Claims

1. An optical imaging system, characterized in that: Comprising: A six - lens group, including a first lens, a second lens, a third lens, a fourth lens, a fifth lens, and a sixth lens arranged in sequence from the object side to the image side along the optical axis; the first lens, the fourth lens, and the sixth lens have negative optical powers, and the second lens, the third lens, and the fifth lens have positive optical powers; An interval element group, including a fourth interval element placed on the image side of the fourth lens and in contact with the image side of the fourth lens, and a fifth interval element placed on the image side of the fifth lens and in contact with the image side of the fifth lens; And A lens barrel, in which the six - lens group and the interval element group are placed; Wherein, the air interval T56 between the fifth lens and the sixth lens on the optical axis and the central thickness CT6 of the sixth lens on the optical axis satisfy: 1 < T56 / CT6 < 2; The central thickness CT5 of the fifth lens on the optical axis, the maximum thickness CP4 of the fourth interval element, and the interval EP45 between the fourth interval element and the fifth interval element along the optical axis satisfy: 1.3 < (CT5 - CP4) / EP45 < 2.

7.

2. The optical imaging system according to claim 1, characterized in that: The central thickness of the fifth lens on the optical axis is greater than the central thickness of any one of the lenses in the six - lens group other than the fifth lens on the optical axis, and the central thickness CT5 of the fifth lens on the optical axis and the interval EP45 between the fourth interval element and the fifth interval element along the optical axis satisfy: 1.4 < CT5 / EP45 < 2.

6.

3. The optical imaging system according to claim 1, characterized in that: The interval EP45 between the fourth interval element and the fifth interval element along the optical axis, the maximum thickness CP4 of the fourth interval element, and the maximum thickness CP5 of the fifth interval element satisfy: 7 < EP45 / (CP4 + CP5) < 14.

4. The optical imaging system according to claim 1, characterized in that: The curvature radius R11 of the object side of the sixth lens and the curvature radius R12 of the image side of the sixth lens satisfy: - 3.5 < R11 / R12 < - 0.5, and the effective focal length f6 of the sixth lens, the refractive index N6 of the sixth lens, and the outer diameter D5m of the image side of the fifth interval element satisfy: - 4.5 < D5m / f6×N6 < - 1.

5.

5. The optical imaging system according to claim 1, characterized in that: The central thickness CT5 of the fifth lens on the optical axis and the outer diameter D5s of the object side of the fifth interval element satisfy: 3 < D5s / CT5 < 6.

6. The optical imaging system according to claim 1, characterized in that: The effective focal length f4 of the fourth lens, the outer diameter D4s of the object side of the fourth interval element, and the inner diameter d4m of the image side of the fourth interval element satisfy: - 2 < (D4s - d4m) / f4 < 0.

7. The optical imaging system according to claim 1, characterized in that: The axial distance SAG52 between the intersection point of the image side of the fifth lens and the optical axis and the vertex of the effective radius of the image side of the fifth lens, the axial distance SAG61 between the intersection point of the object side of the sixth lens and the optical axis and the vertex of the effective radius of the object side of the sixth lens, and the interval EP45 between the fourth interval element and the fifth interval element along the optical axis satisfy: 1.2 < |SAG61 + SAG52| / EP45 < 2.

4.

8. The optical imaging system according to any one of claims 1 to 7, characterized in that: The spacer element group further includes a third spacer element disposed on and in contact with the image side of the third lens. Wherein, the central thickness CT4 of the fourth lens on the optical axis, the interval EP34 between the third spacer element and the fourth spacer element along the optical axis, and the interval EP45 between the fourth spacer element and the fifth spacer element along the optical axis satisfy: 3 < (EP34 + EP45) / CT4 < 6.

9. The optical imaging system according to any one of claims 1 to 7, characterized in that: The spacer element group further includes a third spacer element disposed on and in contact with the image side of the third lens. Wherein, the radius of curvature R5 of the object side of the third lens and the radius of curvature R6 of the image side of the third lens satisfy: -1.8 < R6 / R5 < -0.5, and the effective focal length f3 of the third lens, the central thickness CT3 of the third lens on the optical axis, and the maximum thickness CP3 of the third spacer element satisfy: 1.5 < f3 / (CP3 + CT3)) < 3.

5.

10. The optical imaging system according to any one of claims 1 to 7, characterized in that: The spacer element group further includes a second spacer element disposed on and in contact with the image side of the second lens and a third spacer element disposed on and in contact with the image side of the third lens. Wherein, the combined focal length f23 of the second lens and the third lens, the air interval T23 between the second lens and the third lens on the optical axis, and the interval EP23 between the second spacer element and the third spacer element along the optical axis satisfy: 2 < f23 / (EP23 + T23) < 4.

5.

11. The optical imaging system according to any one of claims 1 to 7, characterized in that: The spacer element group further includes a second spacer element disposed on and in contact with the image side of the second lens and a third spacer element disposed on and in contact with the image side of the third lens. Wherein, the inner diameter d2s of the object side of the second spacer element, the outer diameter D2s of the object side of the second spacer element, the inner diameter d3s of the object side of the third spacer element, and the outer diameter D3s of the object side of the third spacer element satisfy: 1 < (D3s - d3s) / (D2s - d2s) < 3.

12. The optical imaging system according to any one of claims 1 to 7, characterized in that: The spacer element group further includes a second spacer element disposed on and in contact with the image side of the second lens and a third spacer element disposed on and in contact with the image side of the third lens. Wherein, the maximum thickness CP2 of the second spacer element and the maximum thickness CP3 of the third spacer element satisfy: 16 < CP2 / CP3 < 23.

13. The optical imaging system according to any one of claims 1 to 7, characterized in that: The spacer element group further includes a first spacer element disposed on and in contact with the image side of the first lens. Wherein, the inner diameter d1s of the object side of the first spacer element and the entrance pupil diameter EPD of the optical imaging system satisfy: 1.2 < d1s / EPD < 1.

8.

14. The optical imaging system according to any one of claims 1 to 7, characterized in that: The spacer element group further includes a second spacer element disposed on and in contact with the image side of the second lens. Among them, the maximum thickness of the second spacer element is greater than the maximum thickness of any one of the spacer elements in the spacer element group except the second spacer element, and the air gap T12 between the first lens and the second lens on the optical axis and the maximum thickness CP2 of the second spacer element satisfy: 1 < T12 / CP2 < 2.

1.

15. The optical imaging system according to any one of claims 1 to 7, characterized in that: The spacer element group further includes a second spacer element disposed on the image side of the second lens and in contact with the image side of the second lens, and a second auxiliary spacer element disposed on the image side of the second spacer element and in contact with the image side of the second spacer element. Among them, the effective focal length f2 of the second lens and the outer diameter D2bs of the object side surface of the second auxiliary spacer element satisfy: 1.2 < f2 / D2bs < 6.8, and the effective focal length f3 of the third lens, the refractive index N3 of the third lens and the inner diameter d2bm of the image side surface of the second auxiliary spacer element satisfy: 1.3 < f3 / d2bm×N3 < 2.

1.

16. The optical imaging system according to any one of claims 1 to 7, characterized in that: Half of the maximum field of view angle Semi-FOV of the optical imaging system satisfies: 60° < Semi-FOV < 68°.

Images