Optical imaging system

Abstract

The application discloses an optical imaging system, which comprises a lens barrel, a six-piece lens group and a spacer element group arranged in the lens barrel; the six-piece lens group comprises a first lens, a second lens, a third lens, a fourth lens, a fifth lens and a sixth lens arranged in sequence from an object side to an image side along an optical axis; the first lens, the fourth lens and the sixth lens have negative refractive powers, and the second lens, the third lens and the fifth lens have positive refractive powers; the spacer element group comprises a fourth spacer element arranged on and in contact with an image side surface of the fourth lens and a fifth spacer element arranged on and in contact with an image side surface of the fifth lens; wherein an air gap T56 of the fifth lens and the sixth lens on the optical axis and a central thickness CT6 of the sixth lens on the optical axis satisfy 1 < T56 / CT6 < 2; a central thickness CT5 of the fifth lens on the optical axis, a maximum thickness CP4 of the fourth spacer element and a spacing EP45 of the fourth spacer element and the fifth spacer element along the optical axis satisfy 1.3 < (CT5-CP4) / EP45 < 2.7.

Description

Technical Field

[0001] This 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 varies.

[0003] Currently, six-piece optical imaging systems have become the 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 Invention

[0004] This 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] In a first aspect of this application, there is provided such an optical imaging system, which includes a lens barrel, a six-piece lens group and a spacer element group disposed within 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 surface of the fourth lens and in contact with the image side surface of the fourth lens, and a fifth spacer element disposed on the image side surface of the fifth lens and in contact with the image side surface 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 this 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. Among them, 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. Among them, 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 this application, the spacer element group further includes a second spacer element disposed on and in contact with the image-side surface of the second lens, and a third spacer element disposed on and in contact with the image-side surface of the third lens, wherein the combined focal length f23 of the second and third lenses, the air gap T23 between the second and third lenses on the optical axis, and the spacing EP23 between the second and third spacer elements along the optical axis satisfy: 2 <f23 / (EP23+T23)<4.5。

[0015] According to an exemplary embodiment of this 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 third spacer element disposed on the image side of the third lens 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.

[0016] According to an exemplary embodiment of this application, the spacer element group further includes a second spacer element disposed on and in contact with the image-side surface of the second lens, and a third spacer element disposed on 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 this application, the spacer element group further includes a first spacer element disposed on 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 1.2 with the entrance pupil diameter EPD of the optical imaging system. <d1s / EPD<1.8。

[0018] According to an exemplary embodiment of this application, the spacer element group further includes a second spacer element disposed on 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 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 satisfies the following condition: 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 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 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] Figures 5A to 5D Respectively show the axial chromatic aberration curve, astigmatism curve, distortion curve and lateral chromatic aberration curve of the optical imaging system according to Embodiment 1, 2 or 3 of the present application;

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

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

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

[0031] Figures 9A to 9D The on-axis chromatic aberration curve, astigmatism curve, distortion curve, and magnification chromatic aberration curve of the optical imaging system according to Embodiments 4, 5, or 6 of this application are shown respectively.

[0032] Figure 10 A schematic diagram of the structure of an optical imaging system according to Embodiment 7 of this application is shown;

[0033] Figure 11 A schematic diagram of the structure of an optical imaging system according to Embodiment 8 of this application is shown;

[0034] Figure 12 A schematic diagram of the structure of an optical imaging system according to Embodiment 9 of this application is shown;

[0035] Figures 13A to 13D The on-axis chromatic aberration curve, astigmatism curve, distortion curve, and magnification chromatic aberration curve of the optical imaging system according to Embodiments 7, 8, or 9 of this application are shown respectively.

[0036] Figure 14A The modulation transfer function (MTF) curves constrained by the diffraction limit are shown for an optical imaging system that satisfies T56 / CT6=1.26 and (CT5-CP4) / EP45=1.79.

[0037] Figure 14B The modulation transfer function curves constrained by the diffraction limit of the optical imaging system are shown when T56 / CT6=1.33 and (CT5-CP4) / EP45=2.04.

[0038] Figure 14C The modulation transfer function curves constrained by the diffraction limit of the optical imaging system are shown when T56 / CT6 = 0.01 and (CT5-CP4) / EP45 = 0.001; and

[0039] Figure 14D The modulation transfer function curves constrained by the diffraction limit of the optical imaging system are shown when T56 / CT6=12.2 and (CT5-CP4) / EP45=14. Detailed Implementation

[0040] To better understand this application, various aspects of this application will be described in more detail with reference to the accompanying drawings. It should be understood that these detailed descriptions are merely illustrative of exemplary embodiments of this application and are not intended to limit the scope of this application in any way. Throughout the specification, the same reference numerals refer to the same elements.

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

[0042] In the accompanying 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 illustrated by way of example. That is, the shapes of the spherical or aspherical surfaces are not limited to those shown in the drawings. The drawings are for illustrative purposes 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 location of the convexity 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 location of the concaveness 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 subject is called the object-side surface of the lens, and the surface of each lens closest to the imaging plane is called the image-side surface of the lens.

[0044] It should also be understood that the terms "comprising" 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. Furthermore, when describing embodiments of this application, the word "may" is used to mean "one or more embodiments of this application." And the term "exemplary" is intended to refer to an example or illustration.

[0045] Unless otherwise specified, all terms used herein (including technical and scientific terms) shall have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains. It should also be understood that terms (e.g., those defined in common dictionaries) shall be interpreted as having the meaning consistent with their meaning in the context of the relevant art and shall not be interpreted in an idealized or overly formalized sense, unless expressly so specified herein.

[0046] It should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other. This application will now be described in detail with reference to the accompanying drawings and embodiments.

[0047] Figure 1 This is a structural layout diagram and a schematic diagram of some parameters of an optical imaging system according to an exemplary embodiment of this application. (Reference) Figure 1 d1s represents the inner diameter of the object side of the first spacer element, d2s represents the inner diameter of the object side of the second spacer element, D2s represents the outer diameter of the object side of the second spacer element, d3s represents the inner diameter of the object side of the third spacer element, D3s represents the outer diameter of the object side of the third spacer element, d4m represents the inner diameter of the image side of the fourth spacer element, D4s represents the outer diameter of the object side of the fourth spacer element, D5s represents the outer diameter of the object side of the fifth spacer element, D5m represents the outer diameter of the image side of the fifth spacer element, d2bm represents the inner diameter of the image side of the second auxiliary spacer element, D2bs represents the outer diameter of the object side of the second auxiliary spacer element, CP2 represents the maximum thickness of the second spacer element, CP3 represents the maximum thickness of the third spacer element, CP4 represents the maximum thickness of the fourth spacer element, CP5 represents the maximum thickness of the fifth spacer element, EP23 represents the spacing between the second and third spacer elements along the optical axis, EP34 represents the spacing between the third and fourth spacer elements along the optical axis, and EP45 represents the spacing between the fourth and fifth spacer elements along the optical axis.

[0048] refer to Figures 2 to 4 , Figures 6 to 8 as well as Figures 10 to 12 The first aspect of this application provides an optical imaging system that may include a six-lens group, comprising a first lens, a second lens, a third lens, a fourth lens, a fifth lens, and a sixth lens arranged sequentially along the optical axis from the object side to the image side. An air gap may exist between any two adjacent lenses in the first to sixth lenses.

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

[0050] In an exemplary embodiment, the second lens may have positive optical power, with its object side being concave and its image side being convex.

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

[0052] In an exemplary embodiment, the fourth lens may have negative optical power, with its object side being convex or concave and its image side being concave.

[0053] In an exemplary embodiment, the fifth lens may have positive optical power, with its object side being convex and its image side 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 contact 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 contact 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 contact 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 contact 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 contact 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 contact 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 surface, and an inner ring surface. 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 outermost surface of the lens barrel away from the optical axis is the outer ring surface, and the innermost surface of the lens barrel closest to the optical axis is the inner ring surface.

[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 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 is 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] Figure 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; Figure 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; Figure 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; Figure 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 Figure 14A and Figure 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 Figure 14C and Figure 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 other lens in the six-piece lens group except 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 spacer element and the fifth spacer element 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, being 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 and fifth spacer elements can be constrained within a reasonable range, avoiding problems such as easy generation of stray light caused by too large thickness of the spacer element or difficulty in processing and forming due to too small 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. 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 processing 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 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 risk of stray light in the optical imaging system.

[0065] In an exemplary embodiment, 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 may satisfy: 1.2 < |SAG61 + SAG52| / EP45 < 2.4. By controlling the above conditional expression, the gap between the edges of the optical surfaces of the fifth lens and the sixth lens and the direction of the effective marginal 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 intervals between the third spacer element and the fourth spacer element along the optical axis and between the fourth spacer element and the fifth spacer element along the optical axis can be respectively limited within a certain range, which is beneficial to constraining the edge thicknesses of the fourth lens and the fifth lens and improving the processing and molding properties of the fourth lens and the fifth lens; at the same time, the central thickness of the fourth lens can also be limited within a certain range, which is beneficial to constraining the thickness ratio of the fourth lens, reducing the molding appearance joint 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 and molding 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 processing and forming properties of the second lens and the third lens, 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 contact 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 contact 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 in the spacer element group other than 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. 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 it 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 processing 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 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. By controlling the above conditional expressions, it is possible to constrain the effective focal lengths of the second lens and the third lens and the refractive index of the third lens, effectively control the overall structure of the second lens and the third lens, and constrain the trend of the effective light rays, which is beneficial to the main value parameters of the system; at the same time, it is also possible to constrain the outer diameter of the object side surface and the inner diameter of the image side surface of the second auxiliary spacer element, and use the second auxiliary spacer element to block the marginal ineffective light rays and the structural reflected stray light rays between the second lens and the third lens, reduce 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 angle of the optical imaging system, Semi-FOV, satisfies: 60° < Semi-FOV < 68°. By constraining half of the maximum field angle of the optical imaging system within the range of 60° to 68°, it is possible to control the aperture size of the optical imaging system and ensure the light incident amount of the optical imaging system.

[0074] In an exemplary embodiment, the maximum thickness CP2 of the second spacer element and the maximum thickness CP3 of the third spacer element satisfy: 1 < CP2 / CP3 < 23. By controlling the above conditional expressions, it is possible to constrain the thicknesses of the second spacer element and the third spacer element within a reasonable range, and avoid the problems of easy generation of stray light caused by too large thickness of the spacer element or difficult processing and forming caused by too small thickness.

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

[0076] The optical imaging system according to the above embodiments of this application can employ six lenses and at least one spacer element. By rationally allocating the parameters of each lens and each spacer element, the stray light risk of the optical imaging system can be reduced, and the fabrication formability, assembly stability, and imaging quality of the optical imaging system can be improved.

[0077] In embodiments of this application, at least one of the surfaces of the first to sixth lenses is an aspherical surface. An aspherical lens is characterized by a continuously changing curvature from its center to its periphery. Unlike a spherical lens, which has a constant curvature from its center to its periphery, an aspherical lens has superior curvature radius characteristics, offering advantages in improving distortion and astigmatism. By using an aspherical lens, aberrations occurring during imaging can be eliminated as much as possible, thereby improving image quality. Optionally, both the object-side and image-side surfaces of the second to sixth lenses are aspherical surfaces.

[0078] A second aspect of this application provides an optical imaging system comprising a lens barrel and a six-element lens group and a spacer element group disposed within the lens barrel. The six-element lens group includes a first lens, a second lens, a third lens, a fourth lens, a fifth lens, and a sixth lens arranged sequentially along the optical axis from the object side to the image side; the first, fourth, and sixth lenses have negative optical power, and the second, third, and fifth lenses have positive optical power. The spacer element group 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.

[0079] Among them, half of the maximum field angle of view 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 spacer 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 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 between the second lens and the third lens, reducing the sensitivity of the lens, and more beneficial to controlling the overall external dimensions 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 spacer 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 improving 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 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-element lens group and a spacer element group housed within the lens barrel. The six-element lens group, arranged sequentially along the optical axis from the object side to the image side, 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. An aperture stop STO can be positioned 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 elements prevent excess light from entering the next lens during the imaging process, while also ensuring better contact between the lens and the lens barrel, thus enhancing the structural stability of the optical imaging system.

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

[0086] Table 1 shows the basic parameters of the optical imaging system of Example 1, where the units for 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 image-side surface of any one of the first lens E1 to the sixth lens E6 are aspherical surfaces, and the surface shape x of each aspherical lens can be defined using, but is not limited to, the following aspherical formula:

[0091]

[0092] Where x is the distance vector from the vertex of the aspherical surface at a height of h along the optical axis; c is the paraxial curvature of the aspherical surface, c = 1 / R (i.e., the paraxial curvature c is the reciprocal of the radius of curvature R in Table 1 above); k is the conic coefficient; Ai is the i-th order correction coefficient of the aspherical surface. Table 2 gives the higher-order coefficients A4, A6, A8, A12 that can be used for each aspherical surface S1-S12 in Example 1. 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 is for reference Figure 3 An optical imaging system according to Embodiment 2 of this application is described.

[0098] like Figure 3 As shown, the optical imaging system includes a lens barrel and a six-element lens group and a spacer element group housed within the lens barrel. The six-element lens group, arranged sequentially along the optical axis from the object side to the image side, 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. An aperture stop STO can be positioned 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 elements prevent excess light from entering the next lens during the imaging process, while also ensuring better contact between the lens and the lens barrel, thus enhancing the structural stability of the optical imaging system.

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

[0100] Example 3

[0101] The following is for reference Figure 4 An optical imaging system according to Embodiment 3 of this application is described.

[0102] like Figure 4 As shown, the optical imaging system includes a lens barrel and a six-element lens group and a spacer element group housed within the lens barrel. The six-element lens group, arranged sequentially along the optical axis from the object side to the image side, 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. An aperture stop STO can be positioned 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 elements prevent excess light from entering the next lens during the imaging process, while also ensuring better contact between the lens and the lens barrel, thus enhancing the structural stability of the optical imaging system.

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

[0104] Figure 5A The on-axis chromatic aberration curves of the optical imaging systems of Examples 1, 2, and 3 are shown, which represent the deviation of the focal point of light of different wavelengths after passing through the optical imaging system. Figure 5BThe astigmatism 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 of view angles. Figure 5C The distortion curves of the optical imaging systems of Examples 1, 2, and 3 are shown, representing the distortion magnitude values ​​corresponding to different field of view angles. Figure 5D The magnification chromatic aberration curves of the optical imaging systems of Examples 1, 2, and 3 are shown, representing the deviations in image height at different points on the imaging plane after light passes through the system. According to... Figures 5A to 5D It can be seen that the optical imaging systems given in Examples 1, 2, and 3 can achieve good imaging quality.

[0105] Example 4

[0106] The following is for reference Figure 6 An optical imaging system according to Embodiment 4 of this application is described.

[0107] like Figure 6 As shown, the optical imaging system includes a lens barrel and a six-element lens group and a spacer element group housed within the lens barrel. The six-element lens group, arranged sequentially along the optical axis from the object side to the image side, 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. An aperture stop STO can be positioned 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 elements prevent excess light from entering the next lens during the imaging process, while also ensuring better contact between the lens and the lens barrel, thus enhancing the structural stability of the optical imaging system.

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

[0109] Table 3 shows the basic parameters of the optical imaging system of Example 4, where the units for 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 image-side surface of any one of the lenses, from the first lens E1 to the sixth lens E6, are aspherical. Table 4 shows the higher-order coefficients A4, A6, A8, and A6 that can be used for the aspherical surfaces S1-S12 in Embodiment 4. 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 is for reference Figure 7 An optical imaging system according to Embodiment 5 of this application is described.

[0118] like Figure 7 As shown, the optical imaging system includes a lens barrel and a six-element lens group and a spacer element group housed within the lens barrel. The six-element lens group, arranged sequentially along the optical axis from the object side to the image side, 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. An aperture stop STO can be positioned 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 elements prevent excess light from entering the next lens during the imaging process, while also ensuring better contact between the lens and the lens barrel, thus enhancing the structural stability of the optical imaging system.

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

[0120] Example 6

[0121] The following is for reference Figure 8 An optical imaging system according to Embodiment 6 of this application is described.

[0122] like Figure 8 As shown, the optical imaging system includes a lens barrel and a six-element lens group and a spacer element group housed within the lens barrel. The six-element lens group, arranged sequentially along the optical axis from the object side to the image side, 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. An aperture stop STO can be positioned 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 elements prevent excess light from entering the next lens during the imaging process, while also ensuring better contact between the lens and the lens barrel, thus enhancing the structural stability of the optical imaging system.

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

[0124] Figure 9A The on-axis chromatic aberration curves of the optical imaging systems of Examples 4, 5, and 6 are shown, which represent the deviation of the focal point of light of different wavelengths after passing through the optical imaging system. Figure 9BAstigmatism curves of the optical imaging systems of Examples 4, 5, and 6 are shown, representing the meridional and sagittal image plane curvatures corresponding to different field of view angles. Figure 9C The distortion curves of the optical imaging systems of Examples 4, 5, and 6 are shown, representing the distortion magnitude values ​​corresponding to different field of view angles. Figure 9D The magnification chromatic aberration curves of the optical imaging systems of Examples 4, 5, and 6 are shown, representing the deviations in image height at different points on the imaging plane after light passes through the system. According to... Figures 9A to 9D It can be seen that the optical imaging systems given in Examples 4, 5, and 6 can achieve good imaging quality.

[0125] Example 7

[0126] The following is for reference Figure 10 An optical imaging system according to Embodiment 7 of this application is described.

[0127] like Figure 10 As shown, the optical imaging system includes a lens barrel and a six-element lens group and a spacer element group housed within the lens barrel. The six-element lens group, arranged sequentially along the optical axis from the object side to the image side, 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. An aperture stop STO can be positioned 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 elements prevent excess light from entering the next lens during the imaging process, while also ensuring better contact between the lens and the lens barrel, thus enhancing the structural stability of the optical imaging system.

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

[0129] Table 5 shows the basic parameters of the optical imaging system of Example 7, where the units for 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 image-side surface of any one of the lenses, from the first lens E1 to the sixth lens E6, are aspherical. Table 6 shows the higher-order coefficients A4, A6, A8, and A6 that can be used for the aspherical surfaces S1-S12 in Embodiment 7. 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 is for reference Figure 11 An optical imaging system according to Embodiment 8 of this application is described.

[0138] like Figure 11 As shown, the optical imaging system includes a lens barrel and a six-element lens group and a spacer element group housed within the lens barrel. The six-element lens group, arranged sequentially along the optical axis from the object side to the image side, 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. An aperture stop STO can be positioned 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 elements prevent excess light from entering the next lens during the imaging process, while also ensuring better contact between the lens and the lens barrel, thus enhancing the structural stability of the optical imaging system.

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

[0140] Example 9

[0141] The following is for reference Figure 12 An optical imaging system according to Embodiment 9 of this application is described.

[0142] like Figure 12 As shown, the optical imaging system includes a lens barrel and a six-element lens group and a spacer element group housed within the lens barrel. The six-element lens group, arranged sequentially along the optical axis from the object side to the image side, 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. An aperture stop STO can be positioned 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 elements prevent excess light from entering the next lens during the imaging process, while also ensuring better contact between the lens and the lens barrel, thus enhancing the structural stability of the optical imaging system.

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

[0144] Figure 13A The on-axis chromatic aberration curves of the optical imaging systems of Examples 7, 8, and 9 are shown, which represent the deviation of the focal point of light of different wavelengths after passing through the optical imaging system. Figure 13BAstigmatism curves of the optical imaging systems of Examples 7, 8, and 9 are shown, representing the meridional and sagittal image plane curvatures corresponding to different field of view angles. Figure 13C The distortion curves of the optical imaging systems of Examples 7, 8, and 9 are shown, representing the distortion magnitude values ​​corresponding to different field of view angles. Figure 13D The magnification chromatic aberration curves of the optical imaging systems of Examples 7, 8, and 9 are shown, representing the deviations in image height at different points on the imaging plane after light passes through the system. According to... Figures 13A to 13D It can be seen that the optical imaging systems given 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, and SAG61 for each embodiment in Examples 1-9. The unit for Semi-FOV is °, and the units for all parameters in Table 7 other than Semi-FOV are 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 d1s, d2s, D2s, d3s, D3s, d4m, D4s, D5s, D5m, d2bm, D2bs, CP2, CP3, CP4, CP5, EP23, EP34, and EP45 for each embodiment in Examples 1-9. These parameters can be calculated according to... Figure 1 The measurements were obtained using the annotation method shown, and the units of the parameters listed in Table 8 are all in mm.

[0149]

[0150]

[0151] Tables 8 and 9 show the values ​​of the conditional expressions for each of the embodiments in Examples 1-9.

[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] This application also provides an imaging device, whose electronic photosensitive element can be a photocoupled device (CCD) or a complementary metal oxide semiconductor device (CMOS). The imaging device can be a stand-alone imaging device such as a digital camera, an imaging module integrated into 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 merely a preferred embodiment of this application and an explanation of the technical principles employed. Those skilled in the art should understand that the scope of the invention involved in this application is not limited to technical solutions formed by specific combinations of the above-described technical features, but should also cover other technical solutions formed by arbitrary combinations of the above-described technical features or their equivalents without departing from the inventive concept. For example, technical solutions formed by substituting the above features with (but not limited to) technical features with similar functions disclosed in this application.

Claims

1. An optical imaging system, characterized in that, include: A six-element lens group includes a first lens, a second lens, a third lens, a fourth lens, a fifth lens, and a sixth lens arranged sequentially along the optical axis from the object side to the image side; 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 group includes a fourth spacer element disposed on the image-side surface of the fourth lens and in contact with the image-side surface of the fourth lens, and a fifth spacer element disposed on the image-side surface of the fifth lens and in contact with the image-side surface of the fifth lens. as well as The lens barrel, in which the six-element lens group and the spacer element group are placed; Wherein, the air gap 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 satisfy: 1.2553≤T56 / CT6≤1.5910; The center thickness CT5 of the fifth lens on the optical axis, the maximum thickness CP4 of the fourth spacer element, and the spacing EP45 of the fourth and fifth spacers along the optical axis satisfy: 1.5910≤(CT5-CP4) / EP45≤2.1838; The image-side surface of the first lens is concave; The object-side surface of the fifth lens is convex, and the image-side surface is also convex. The object-side surface of the sixth lens is concave, and the image-side surface is also concave. The optical imaging system has six lenses with optical power.

2. The optical imaging system according to claim 1, characterized in that, The center thickness of the fifth lens on the optical axis is greater than the center thickness of any lens in the six-element lens group other than the fifth lens on the optical axis, and the center thickness CT5 of the fifth lens on the optical axis and the spacing EP45 of the fourth spacer element and the fifth spacer element along the optical axis satisfy: 1.6299≤CT5 / EP45≤2.2405.

3. The optical imaging system according to claim 1, characterized in that, The spacing EP45 between the fourth and fifth spacers along the optical axis, the maximum thickness CP4 of the fourth spacer, and the maximum thickness CP5 of the fifth spacer satisfy the following: 8.8182≤EP45 / (CP4+CP5)≤12.8409.

4. The optical imaging system according to claim 1, characterized in that, The radius of curvature R11 of the object side of the sixth lens and the radius of curvature R12 of the image side of the sixth lens satisfy: -2.7216≤R11 / R12≤-1.5206. 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 spacer element satisfy: -3.8713≤D5m / f6×N6≤-2.2899.

5. The optical imaging system according to claim 1, characterized in that, The center thickness CT5 of the fifth lens on the optical axis and the outer diameter D5s of the object side of the fifth spacer element satisfy the following condition: 3.4010≤D5s / CT5≤5.6489.

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 spacer element, and the inner diameter d4m of the image side of the fourth spacer element satisfy: -1.3302≤(D4s-d4m) / f4≤-0.4492.

7. The optical imaging system according to claim 1, characterized in that, 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 spacing EP45 of the fourth spacer element and the fifth spacer element along the optical axis satisfy: 1.5927≤|SAG61+SAG52| / EP45≤2.0821.

8. The optical imaging system according to any one of claims 1-7, characterized in that, The spacer element group further includes a third spacer element disposed on and in contact with the image-side surface of the third lens. Wherein, the center thickness CT4 of the fourth lens on the optical axis, the spacing EP34 of the third and fourth spacers along the optical axis and the spacing EP45 of the fourth and fifth spacers along the optical axis satisfy: 4.0000≤(EP34+EP45) / CT4≤4.7960.

9. The optical imaging system according to any one of claims 1-7, characterized in that, The spacer element group further includes a third spacer element disposed on and in contact with the image-side surface of the third lens. 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: -1.2648≤R6 / R5≤-0.9154. The effective focal length f3 of the third lens, the center thickness CT3 of the third lens on the optical axis and the maximum thickness CP3 of the third spacer element satisfy: 2.0509≤f3 / (CP3+CT3))≤2.9948.

10. The optical imaging system according to any one of claims 1-7, characterized in that, The spacer element group further includes a second spacer element disposed on and in contact with the image-side surface of the second lens, and a third spacer element disposed on 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 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: 2.6875≤f23 / (EP23+T23)≤3.7377.

11. The optical imaging system according to any one of claims 1-7, characterized in that, The spacer element group further includes a second spacer element disposed on and in contact with the image-side surface of the second lens, and a third spacer element disposed on and in contact with the image-side surface 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: 1.3775≤(D3s-d3s) / (D2s-d2s)≤2.7174.

12. The optical imaging system according to any one of claims 1-7, characterized in that, The spacer element group further includes a second spacer element disposed on and in contact with the image-side surface of the second lens, and a third spacer element disposed on and in contact with the image-side surface of the third lens. The maximum thickness CP2 of the second spacer element and the maximum thickness CP3 of the third spacer element satisfy the following condition: 17.0909≤CP2 / CP3≤21.4091.

13. The optical imaging system according to any one of claims 1-7, characterized in that, The spacer element group further includes a first spacer element disposed on and in contact with the image-side surface 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: 1.4704≤d1s / EPD≤1.6787.

14. The optical imaging system according to any one of claims 1-7, characterized in that, The spacer element group further includes a second spacer element disposed on 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 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 satisfies the following condition with respect to the maximum thickness CP2 of the second spacer element: 1.3182≤T12 / CP2≤1.8381.

15. The optical imaging system according to any one of claims 1-7, 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 second auxiliary spacer element disposed on 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: 1.7079≤f2 / D2bs≤6.3646, 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: 1.6266≤f3 / d2bm×N3≤1.8957.

16. The optical imaging system according to any one of claims 1-7, characterized in that, The maximum field of view (Semi-FOV) of the optical imaging system is half of the following: 61.0000°≤Semi-FOV≤66.0000°.

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