Optical imaging system

Abstract

The present application discloses an optical imaging system, which includes, in order from the object side to the image side along the optical axis: a first lens, a second lens, a third lens, a fourth lens, a fifth lens, a sixth lens, and a seventh lens with optical power; the optical imaging system satisfies the following conditions: 1.5<f / EPD<2.0; 3.5<CT6 / CT5<6.0; ‑2.5<R6 / R7<‑1.0; and ‑3.5<SAG71 / SAG31<‑2.5; wherein f is the effective focal length of the optical imaging system, EPD is The entrance pupil diameter of the optical imaging system, CT5 is the center thickness of the fifth lens on the optical axis, CT6 is the center thickness of the sixth lens on the optical axis, R6 is the curvature radius of the image side surface of the third lens, R7 is the curvature radius of the object side surface of the fourth lens, SAG71 is the axial distance from the intersection of the object side surface of the seventh lens and the optical axis to the effective radius vertex of the object side surface of the seventh lens, and SAG31 is the axial distance from the intersection of the object side surface of the third lens and the optical axis to the effective radius vertex of the object side surface of the third lens.

Description

[0001] Divisional application statement

[0002] This application is a divisional application of the Chinese invention patent application with the invention name “Optical Imaging System” and application number 201910808369.8 filed on August 29, 2019. Technical Field

[0003] The present application relates to the field of optical elements, and more particularly, to an optical imaging system including seven lenses. Background Art

[0004] In recent years, with the development of science and technology, portable electronic products have been constantly updated, and the various components therein have been constantly updated. For example, the performance of photosensitive elements has been improved and the size has been reduced. In addition, the image software functions and video software functions on portable electronic products have also been continuously developed. The market demand for optical imaging systems suitable for portable electronic products has gradually increased.

[0005] The market needs an optical imaging system that can achieve both miniaturization and good imaging quality. Summary of the Invention

[0006] The present application provides an optical imaging system that is applicable to portable electronic products and can at least solve or partially solve at least one of the above-mentioned shortcomings in the prior art.

[0007] The present application provides an optical imaging system, which includes, in order from the object side to the image side along the optical axis: a first lens, a second lens, a third lens, a fourth lens, a fifth lens, a sixth lens, and a seventh lens, each having optical power. The optical imaging system can satisfy the following conditions: 1.5<f / EPD<2.0; and 3.5<CT6 / CT5<6.0; wherein f is the effective focal length of the optical imaging system, EPD is the entrance pupil diameter of the optical imaging system, CT5 is the center thickness of the fifth lens on the optical axis, and CT6 is the center thickness of the sixth lens on the optical axis.

[0008] In one embodiment, the optical imaging system may satisfy the condition: -2.5<R6 / R7<-1.0; wherein R6 is the curvature radius of the image side surface of the third lens, and R7 is the curvature radius of the object side surface of the fourth lens.

[0009] In one embodiment, the optical imaging system may satisfy the condition: -3.5<SAG71 / SAG31<-2.5; wherein, SAG71 is the on-axis distance from the intersection of the object side surface of the seventh lens and the optical axis to the vertex of the effective radius of the object side surface of the seventh lens, and SAG31 is the on-axis distance from the intersection of the object side surface of the third lens and the optical axis to the vertex of the effective radius of the object side surface of the third lens.

[0010] In one embodiment, the optical imaging system may satisfy the condition: 1.5<ET7 / (ET3+ET6)<4.0; wherein ET3 is the edge thickness of the third lens, ET6 is the edge thickness of the sixth lens, and ET7 is the edge thickness of the seventh lens.

[0011] In one embodiment, the effective focal length f1 of the first lens and the effective focal length f3 of the third lens may satisfy 1.0<f1 / f3<2.0.

[0012] In one embodiment, the effective focal length f2 of the second lens and the effective focal length f4 of the fourth lens may satisfy 1.0<f4 / f2<1.5.

[0013] In one embodiment, the effective focal length f6 of the sixth lens and the curvature radius R11 of the object-side surface of the sixth lens may satisfy 1.5<f6 / R11<2.5.

[0014] In one embodiment, a center thickness CT1 of the first lens on the optical axis and a center thickness CT2 of the second lens on the optical axis may satisfy 1.5≤CT1 / CT2<2.0.

[0015] In one embodiment, a center thickness CT6 of the sixth lens on the optical axis and a center thickness CT7 of the seventh lens on the optical axis may satisfy 2.0<CT6 / CT7<3.5.

[0016] In one embodiment, a distance T34 between the third lens and the fourth lens on the optical axis and a distance T67 between the sixth lens and the seventh lens on the optical axis may satisfy 2.0≤T67 / T34<4.0.

[0017] In one embodiment, a spacing distance T12 between the first lens and the second lens on the optical axis, a spacing distance T45 between the fourth lens and the fifth lens on the optical axis, and a spacing distance T56 between the fifth lens and the sixth lens on the optical axis may satisfy 2.5<(T45+T56) / T12<3.5.

[0018] In one embodiment, a curvature radius R2 of the image-side surface of the first lens and a curvature radius R3 of the object-side surface of the second lens may satisfy 2.0<(R2+R3) / (R2-R3)<3.5.

[0019] In one embodiment, a curvature radius R11 of the object-side surface of the sixth lens element and a curvature radius R14 of the image-side surface of the seventh lens element may satisfy 1.0<R11 / R14<2.5.

[0020] In one embodiment, a center thickness CT3 of the third lens on the optical axis and a center thickness CT4 of the fourth lens on the optical axis may satisfy 3.0<CT3 / CT4<4.0.

[0021] In one embodiment, the combined focal length f45 of the fourth lens and the fifth lens and the combined focal length f123 of the first lens, the second lens, and the third lens may satisfy -2.5<f45 / f123<-1.5.

[0022] In one embodiment, the refractive index N2 of the second lens element may satisfy N2>1.60, the refractive index N4 of the fourth lens element may satisfy N4>1.60, and the refractive index N5 of the fifth lens element may satisfy N5>1.60.

[0023] In one embodiment, the Abbe number V2 of the second lens may satisfy V2<25.0, the Abbe number V4 of the fourth lens may satisfy V4<25.0, and the Abbe number V5 of the fifth lens may satisfy <25.0.

[0024] In one embodiment, the first lens may have positive optical power, the second lens may have negative optical power, the third lens may have positive optical power, the fourth lens may have negative optical power, the fifth lens may have negative optical power, the sixth lens may have positive optical power, and the seventh lens may have negative optical power.

[0025] In one embodiment, the object-side surface of the first lens may be convex, and the image-side surface may be concave; the object-side surface of the second lens may be convex, and the image-side surface may be concave; the object-side surface of the third lens may be convex, and the image-side surface may be convex; the object-side surface of the fourth lens may be convex, and the image-side surface may be concave; the object-side surface of the fifth lens may be convex, and the image-side surface may be concave; the object-side surface of the sixth lens may be convex; and the image-side surface of the seventh lens may be concave.

[0026] In one embodiment, the number of lenses having optical power in the optical imaging system may be seven.

[0027] This application uses seven lenses. By reasonably allocating the optical focal length, surface shape, center thickness of each lens, and on-axis spacing between lenses, the above-mentioned optical imaging system has at least one beneficial effect of miniaturization, good imaging quality, and easy assembly. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Other features, purposes and advantages of the present application will become more apparent through the following detailed description of non-limiting embodiments in conjunction with the accompanying drawings. In the accompanying drawings:

[0029] Figure 1 1 shows a schematic structural diagram of an optical imaging system according to Example 1 of the present application; Figures 2A to 2C axial chromatic aberration curve, astigmatism curve, and distortion curve of the optical imaging system of Example 1 are respectively shown;

[0030] Figure 31 shows a schematic structural diagram of an optical imaging system according to Example 2 of the present application; Figures 4A to 4C axial chromatic aberration curve, astigmatism curve, and distortion curve of the optical imaging system of Example 2 are respectively shown;

[0031] Figure 5 1 shows a schematic structural diagram of an optical imaging system according to Example 3 of the present application; Figures 6A to 6C axial chromatic aberration curve, astigmatism curve, and distortion curve of the optical imaging system of Example 3 are respectively shown;

[0032] Figure 7 Schematic diagram of the structure of an optical imaging system according to Example 4 of the present application is shown; Figures 8A to 8C axial chromatic aberration curve, astigmatism curve, and distortion curve of the optical imaging system of Example 4 are respectively shown;

[0033] Figure 9 1 shows a schematic structural diagram of an optical imaging system according to Example 5 of the present application; Figures 10A to 10C axial chromatic aberration curve, astigmatism curve, and distortion curve of the optical imaging system of Example 5 are respectively shown;

[0034] Figure 11 1 shows a schematic structural diagram of an optical imaging system according to Example 6 of the present application; 12A to 12C The axial chromatic aberration curve, astigmatism curve, and distortion curve of the optical imaging system of Example 6 are shown respectively. DETAILED DESCRIPTION

[0035] For a better understanding of the present application, various aspects of the present application will be described in more detail with reference to the accompanying drawings. It should be understood that these detailed descriptions are merely descriptions of exemplary embodiments of the present application and are not intended to limit the scope of the present application in any way. Throughout the specification, the same reference numerals refer to the same elements. The expression "and / or" includes any and all combinations of one or more of the associated listed items.

[0036] It should be noted that in this specification, the terms "first," "second," "third," etc., are used solely to distinguish one feature from another and do not limit the features. Thus, the first lens discussed below could also be referred to as the second lens or the third lens without departing from the teachings of this application.

[0037] In the drawings, the thickness, size, and shape of the lenses are slightly exaggerated for ease of illustration. Specifically, the shapes of the spherical and aspherical surfaces shown in the drawings are provided by way of example. That is, the shapes of the spherical and aspherical surfaces are not limited to those shown in the drawings. The drawings are for illustration only and are not drawn strictly to scale.

[0038] In this article, the paraxial region refers to the area near the optical axis. If a lens surface is convex and the location of the convex surface is undefined, it means that the lens surface is convex at least in the paraxial region. If a lens surface is concave and the location of the concave surface is undefined, 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.

[0039] It should also be understood that the terms "comprises," "including," "having," "includes," and / or "comprising," when used in this specification, indicate the presence of the stated features, elements, and / or components, but do not preclude the presence or addition of one or more other features, elements, components, and / or combinations thereof. In addition, when expressions such as "at least one of..." appear after a list of listed features, they modify the entire list of features rather than modifying the individual elements in the list. In addition, when describing embodiments of the present application, "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.

[0040] Unless otherwise defined, all terms used herein (including technical and scientific terms) have the same meaning as commonly understood by those skilled in the art to which this application belongs. It should also be understood that terms (such as those defined in commonly used dictionaries) should be interpreted as having a meaning consistent with their meaning in the context of the relevant technology and will not be interpreted in an idealized or overly formal sense unless expressly defined as such herein.

[0041] It should be noted that, in the absence of conflict, the embodiments and features of the embodiments in this 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.

[0042] The features, principles and other aspects of the present application are described in detail below.

[0043] An optical imaging system according to an exemplary embodiment of the present application may include, for example, seven lenses having optical power: a first lens, a second lens, a third lens, a fourth lens, a fifth lens, a sixth lens, and a seventh lens. These seven lenses are arranged sequentially along the optical axis from the object side to the image side. Among the first through seventh lenses, any two adjacent lenses may have an air gap between them.

[0044] In example embodiments, the first lens may have positive refractive power.

[0045] In an exemplary embodiment, the second lens element may have negative power, the third lens element may have positive power, the fourth lens element may have negative power, the fifth lens element may have negative power, the sixth lens element may have positive power, and the seventh lens element may have negative power. By properly controlling the positive and negative distribution of the power of each component of the system and the lens surface curvature, the low-order aberrations of the system can be effectively balanced. In an exemplary embodiment, the image-side surface of the third lens element may be convex.

[0046] In an exemplary embodiment, the optical imaging system of the present application may satisfy at least one of the following conditional expressions:

[0047] 1.5<f / EPD<2.0 (1);

[0048] 3.5<CT6 / CT5<6.0 (2);

[0049] -2.5<R6 / R7<-1.0 (3);

[0050] -3.5<SAG71 / SAG31<-2.5 (4); and

[0051] 1.5<ET7 / (ET3+ET6)<4.0 (5);

[0052] Among them, f is the effective focal length of the optical imaging system, EPD is the entrance pupil diameter of the optical imaging system, CT5 is the center thickness of the fifth lens on the optical axis, CT6 is the center thickness of the sixth lens on the optical axis, R6 is the radius of curvature of the image side surface of the third lens, R7 is the radius of curvature of the object side surface of the fourth lens, SAG71 is the on-axis distance from the intersection of the object side surface of the seventh lens and the optical axis to the effective radius vertex of the object side surface of the seventh lens (that is, the sag height of the effective radius vertex of the object side surface of the seventh lens), SAG31 is the on-axis distance from the intersection of the object side surface of the third lens and the optical axis to the effective radius vertex of the object side surface of the third lens (that is, the sag height of the effective radius vertex of the object side surface of the third lens), ET3 is the edge thickness of the third lens, ET6 is the edge thickness of the sixth lens, and ET7 is the edge thickness of the seventh lens.

[0053] In an exemplary embodiment, the optical imaging system of the present application may satisfy conditional equation (1). More specifically, the effective focal length f of the optical imaging system and the entrance pupil diameter (EPD) of the optical imaging system may satisfy 1.52 < f / EPD < 1.92. By controlling the ratio of the effective focal length of the optical imaging system to the entrance pupil diameter of the optical imaging system, the amount of light entering the optical imaging system can be controlled, which is beneficial for improving the brightness of the field of view at the imaging surface.

[0054] In an exemplary embodiment, the optical imaging system of the present application may satisfy conditional formula (2). More specifically, the center thickness CT5 of the fifth lens on the optical axis and the center thickness CT6 of the sixth lens on the optical axis may satisfy 3.62<CT6 / CT5<5.58. By controlling the ratio of the center thickness of the fifth lens to the center thickness of the sixth lens, the amount of distortion contributed by the fifth lens and the sixth lens to the optical imaging system can be controlled, which is beneficial for balancing the amount of distortion contributed by each lens to the optical imaging system and for controlling the distortion of each field of view to below 5%, thereby reducing the debugging work of the software used with the optical imaging system. Exemplarily, the optical imaging system also satisfies conditional formula (1), and the optical imaging system has good imaging quality.

[0055] In an exemplary embodiment, the optical imaging system of the present application may satisfy conditional equation (3). More specifically, the curvature radius R6 of the image side surface of the third lens and the curvature radius R7 of the object side surface of the fourth lens may satisfy -2.28<R6 / R7<-1.13. By controlling the ratio of the curvature radius of the image side surface of the third lens to the curvature radius of the object side surface of the fourth lens, it is beneficial to reduce the spherical aberration and astigmatism of the optical imaging system, thereby improving the imaging quality of the optical imaging system. Exemplarily, the optical imaging system also satisfies conditional equations (1) and (2). The optical imaging system has good imaging quality.

[0056] In an exemplary embodiment, the optical imaging system of the present application may satisfy conditional equation (4). More specifically, the on-axis distance SAG71 from the intersection of the object side surface of the seventh lens and the optical axis to the effective radius vertex of the object side surface of the seventh lens and the on-axis distance SAG31 from the intersection of the object side surface of the third lens and the optical axis to the effective radius vertex of the object side surface of the third lens may satisfy -3.05<SAG71 / SAG31<-2.90. By controlling the ratio of the sagittal height of the object side surface of the seventh lens to the sagittal height of the object side surface of the third lens, it is beneficial to reduce the intensity of the ghost image of the optical imaging system and balance the sizes of the various lenses, thereby making the optical imaging system have good assembly processability.

[0057] In an exemplary embodiment, the optical imaging system of the present application may satisfy conditional formula (5). More specifically, the edge thickness ET3 of the third lens, the edge thickness ET6 of the sixth lens, and the edge thickness ET7 of the seventh lens may satisfy 1.53<ET7 / (ET3+ET6)<3.76. By controlling the edge thickness of the third lens, the edge thickness of the sixth lens, and the edge thickness of the seventh lens, the thickness of each lens is made appropriate, which is beneficial to the manufacturing and molding of each lens, and further beneficial to the assembly of an optical imaging system with better quality. When the optical imaging system is in use, there is less stray light in the light beam inside it. Exemplarily, the optical imaging system can also satisfy conditional formula (4), and the optical imaging system has good assembly processability and good imaging quality.

[0058] In an exemplary embodiment, the optical imaging system of the present application can satisfy the conditions (1), (2), (3), (4) and (5), and the third lens, fourth lens, fifth lens, sixth lens and seventh lens of the optical imaging system are matched, so that the optical imaging system is easy to assemble and use and has good imaging quality.

[0059] In an exemplary embodiment, the optical imaging system of the present application may satisfy the conditional equation 1.0 < f1 / f3 < 2.0, where f1 is the effective focal length of the first lens and f3 is the effective focal length of the third lens. More specifically, f1 and f3 may satisfy 1.12 < f1 / f3 < 1.75. By controlling the ratio of the effective focal length of the first lens to the effective focal length of the third lens, the effective focal length of the optical imaging system can be increased while also balancing the field curvature of the optical imaging system.

[0060] In an exemplary embodiment, the optical imaging system of the present application may satisfy the conditional equation 1.0 < f4 / f2 < 1.5, where f2 is the effective focal length of the second lens element and f4 is the effective focal length of the fourth lens element. More specifically, f2 and f4 may satisfy 1.12 < f4 / f2 < 1.38. By controlling the ratio of the effective focal length of the fourth lens element to the effective focal length of the second lens element, distortion in the paraxial region of the imaging plane can be effectively corrected, thereby improving the imaging quality of the optical imaging system.

[0061] In an exemplary embodiment, the optical imaging system of the present application may satisfy the conditional equation 1.5 < f6 / R11 < 2.5, where f6 is the effective focal length of the sixth lens element, and R11 is the radius of curvature of the object-side surface of the sixth lens element. More specifically, f6 and R11 may satisfy 1.58 < f6 / R11 < 2.18. By controlling the ratio of the effective focal length of the sixth lens element to the radius of curvature of the object-side surface of the sixth lens element, the optical imaging system can be optimized to have a large aperture and effectively reduce field curvature and astigmatism.

[0062] In an exemplary embodiment, the optical imaging system of the present application can satisfy the conditional equation 1.5 ≤ CT1 / CT2 < 2.0, where the center thickness CT1 of the first lens on the optical axis and the center thickness CT2 of the second lens on the optical axis satisfy 1.51 ≤ CT1 / CT2 < 1.80. By constraining the ratio of the center thickness of the first lens to the center thickness of the second lens, the distance from the object-side surface of the first lens to the imaging plane of the optical imaging system on the optical axis is constrained, and the first and second lenses are also facilitated to have good machinability.

[0063] In an exemplary embodiment, the optical imaging system of the present application may satisfy the conditional equation 2.0 < CT6 / CT7 < 3.5, where CT6 is the center thickness of the sixth lens on the optical axis, and CT7 is the center thickness of the seventh lens on the optical axis. More specifically, CT6 and CT7 may satisfy 2.03 < CT6 / CT7 < 3.31. Controlling the ratio of the center thickness of the sixth lens to the center thickness of the seventh lens facilitates balancing the sizes of the sixth and seventh lenses, thereby improving assembly stability of the optical imaging system and reducing aberrations in the optical imaging system.

[0064] In an exemplary embodiment, the optical imaging system of the present application may satisfy the conditional equation 2.0 ≤ T67 / T34 < 4.0, where T34 is the distance between the third and fourth lenses on the optical axis, and T67 is the distance between the sixth and seventh lenses on the optical axis. More specifically, T34 and T67 may satisfy 2.42 ≤ T67 / T34 < 3.60. By controlling the air gap between the sixth and fourth lenses, as well as the air gap between the third and fourth lenses, it is beneficial to balance the field curvature produced by the fourth lens and its object-side lens with the field curvature produced by the sixth lens and its image-side lens, thereby providing the optical imaging system with a more balanced field curvature and improving the imaging quality of the optical imaging system.

[0065] In an exemplary embodiment, the optical imaging system of the present application may satisfy the conditional formula 2.5<(T45+T56) / T12<3.5, wherein T12 is the spacing distance between the first lens and the second lens on the optical axis, T45 is the spacing distance between the fourth lens and the fifth lens on the optical axis, and T56 is the spacing distance between the fifth lens and the sixth lens on the optical axis. More specifically, T12, T45, and T56 may satisfy 2.70<(T45+T56) / T12<3.25. By controlling the air spacing between the first lens and the second lens, the air spacing between the fourth lens and the fifth lens, and the air spacing between the fifth lens and the sixth lens, it is beneficial to balance the sizes of the aforementioned lenses, thereby giving the optical imaging system better assembly stability, reducing the aberrations of the optical imaging system, and shortening the total optical length of the optical imaging system.

[0066] In an exemplary embodiment, the optical imaging system of the present application may satisfy the conditional formula 2.0<(R2+R3) / (R2-R3)<3.5, wherein R2 is the radius of curvature of the image side surface of the first lens, and R3 is the radius of curvature of the object side surface of the second lens. More specifically, R2 and R3 may satisfy 2.20<(R2+R3) / (R2-R3)<3.30. By controlling the radius of curvature of the image side surface of the first lens and the radius of curvature of the object side surface of the second lens, the contribution of the image side surface of the first lens and the object side surface of the second lens to the amount of astigmatism of the optical imaging system can be effectively controlled, thereby effectively controlling the image quality of the intermediate field of view and the image quality of the aperture band, so that the optical imaging system has good imaging characteristics.

[0067] In an exemplary embodiment, the optical imaging system of the present application may satisfy the conditional equation 1.0 < R11 / R14 < 2.5, where R11 is the radius of curvature of the object-side surface of the sixth lens element, and R14 is the radius of curvature of the image-side surface of the seventh lens element. More specifically, R11 and R14 may satisfy 1.03 < R11 / R14 < 1.30. By controlling the ratio of the radius of curvature of the object-side surface of the sixth lens element to the radius of curvature of the image-side surface of the seventh lens element, the on-axis aberrations of the optical imaging system can be relatively balanced.

[0068] In an exemplary embodiment, the optical imaging system of the present application can satisfy the conditional equation 3.0 < CT3 / CT4 < 4.0, where CT3 is the center thickness of the third lens on the optical axis, and CT4 is the center thickness of the fourth lens on the optical axis. More specifically, CT3 and CT4 can satisfy 3.05 < CT3 / CT4 < 3.98. By constraining the center thickness of the third and fourth lenses, the thicknesses of the third and fourth lenses can be prevented from being too thin, facilitating the processing of the third and fourth lenses and reducing the difficulty of assembling the third and fourth lenses.

[0069] In an exemplary embodiment, the optical imaging system of the present application may satisfy the conditional equation: -2.5 < f45 / f123 < -1.5, where f45 is the combined focal length of the fourth and fifth lenses, and f123 is the combined focal length of the first, second, and third lenses. More specifically, f45 and f123 may satisfy -2.30 < f45 / f123 < -1.90. By constraining the ratio of the combined focal length of the first, second, and fourth lenses to the combined focal length of the fourth and fifth lenses, the aberrations of the optical imaging system can be effectively controlled, thereby improving the imaging quality of the optical imaging system.

[0070] In an exemplary embodiment, the optical imaging system of the present application can satisfy the following conditions: the refractive index N2 of the second lens element satisfies N2 > 1.60, the refractive index N4 of the fourth lens element satisfies N4 > 1.60, and the refractive index N5 of the fifth lens element satisfies N5 > 1.60. The materials of the second, fourth, and fifth lenses having a refractive index greater than 1.6 facilitate correcting off-axis coma and astigmatism in the optical imaging system, thereby improving image quality in the outer field of view.

[0071] In an exemplary embodiment, the optical imaging system of the present application can satisfy the following conditions: the Abbe number V2 of the second lens element satisfies V2 < 25.0, the Abbe number V4 of the fourth lens element satisfies V4 < 25.0, and the Abbe number V5 of the fifth lens element satisfies V5 < 25.0. By controlling the Abbe numbers of the second lens element, the fourth lens element, and the fifth lens element to be less than 25, the imaging quality of the optical imaging system can be improved.

[0072] In an exemplary embodiment, the optical imaging system may further include at least one aperture. The aperture may be positioned appropriately as needed, for example, between the third and fourth lenses. Optionally, the optical imaging system may further include a filter for correcting color deviation and / or a protective glass for protecting the photosensitive element on the imaging surface.

[0073] The optical imaging system according to the above-described embodiment of the present application can utilize multiple lenses, such as the seven lenses described above. By rationally allocating the focal power, surface shape, center thickness of each lens, and the on-axis spacing between lenses, the imaging system can be effectively reduced in size, its sensitivity can be reduced, and its manufacturability can be improved, making the optical imaging system more amenable to production and processing and suitable for use in portable electronic products. Furthermore, the optical imaging system of the present application also exhibits excellent optical properties, such as miniaturization, good imaging quality, and ease of assembly.

[0074] In an embodiment of the present application, at least one of the mirror surfaces of each lens is an aspherical mirror surface, that is, at least one of the object side surface of the first lens and the image side surface of the seventh lens is an aspherical mirror 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 with a constant curvature from the center of the lens to the periphery of the lens, an aspherical lens has a better curvature radius characteristic, which 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, at least one of the object side surface and the image side surface of each lens in the first lens, the second lens, the third lens, the fourth lens, the fifth lens, the sixth lens and the seventh lens is an aspherical mirror surface. Optionally, the object side surface and the image side surface of each lens in the first lens, the second lens, the third lens, the fourth lens, the fifth lens, the sixth lens and the seventh lens are all aspherical mirror surfaces.

[0075] However, those skilled in the art will appreciate that, without departing from the technical solutions claimed in this application, the number of lenses comprising the optical imaging system can be varied to achieve the various results and advantages described herein. For example, although seven lenses are described as an example in the embodiments, the optical imaging system is not limited to including seven lenses. If desired, the optical imaging system may also include other numbers of lenses.

[0076] Specific embodiments of the optical imaging system applicable to the above-mentioned embodiments will be further described below with reference to the accompanying drawings.

[0077] Example 1

[0078] The following reference Figures 1 to 2C An optical imaging system according to Example 1 of the present application is described. Figure 1 A structural schematic diagram of an optical imaging system according to Example 1 of the present application is shown.

[0079] like Figure 1 As shown, the optical imaging system includes, from the object side to the image side along the optical axis, a first lens E1, a second lens E2, a third lens E3, an aperture STO, a fourth lens E4, a fifth lens E5, a sixth lens E6, a seventh lens E7 and a filter E8.

[0080] The first lens E1 has positive optical power, with its object-side surface S1 being convex and its image-side surface S2 being concave. The second lens E2 has negative optical power, with its object-side surface S3 being convex and its image-side surface S4 being concave. 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 negative optical power, with its object-side surface S9 being convex and its image-side surface S10 being concave. The sixth lens E6 has positive optical power, with its object-side surface S11 being convex and its image-side surface S12 being concave. The seventh lens E7 has negative optical power, with its object-side surface S13 being convex and its image-side surface S14 being concave. The filter E8 has an object-side surface S15 and an image-side surface S16. The optical imaging system has an imaging surface S17 . Light from an object passes through the surfaces S1 to S16 in sequence and is finally imaged on the imaging surface S17 .

[0081] Table 1 shows the basic parameters of the optical imaging system of Example 1, wherein the units of the curvature radius, thickness / distance and focal length are all millimeters (mm).

[0082]

[0083] Table 1

[0084] In Example 1, the effective focal length f of the optical imaging system is 4.00 mm, the on-axis distance TTL from the object-side surface S1 of the first lens E1 to the imaging surface S17 is 5.34 mm, the value ImgH of half the diagonal length of the effective pixel area on the imaging surface S17 is 3.32 mm, and the value Semi-FOV of half the maximum field of view is 40.0°.

[0085] In Example 1, the object-side surface and the image-side surface of any lens among the first lens E1 to the seventh lens E7 are both aspherical surfaces. The surface shape x of each aspherical lens can be defined by, but is not limited to, the following aspherical surface formula:

[0086]

[0087] Wherein, x is the distance vector height of the aspheric surface from the vertex of the aspheric surface 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 conic coefficient; Ai is the correction coefficient of the i-th order of the aspheric surface. Table 2 below 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 10 、A 12 、A 14 、A 16 、A 18 and A 20 .

[0088] Face number A4 A6 A8 A10 A12 A14 A16 A18 A20 S1 -1.5091E-01 -1.9979E-02 1.4944E-02 1.7529E-03 -1.5476E-04 7.0646E-04 4.4171E-04 1.9385E-05 -1.3153E-04 S2 7.7664E-02 -1.8375E-02 6.1924E-03 -1.8615E-03 7.9377E-04 -3.5968E-04 3.5892E-04 -3.9792E-05 -9.6799E-06 S3 -1.2476E-01 4.5932E-03 -5.1256E-03 -5.4093E-04 1.4437E-03 -1.7129E-03 -7.5698E-05 -9.3915E-05 8.7221E-05 S4 -1.0588E-01 9.0697E-03 -9.1181E-03 3.2841E-03 2.7407E-03 -1.7373E-03 -3.4104E-04 9.2400E-05 1.1485E-04 S5 1.7680E-01 1.4829E-02 -4.7129E-03 1.3991E-03 2.4283E-03 2.0100E-04 -7.5520E-05 1.7510E-05 3.0860E-06 S6 -6.6657E-03 5.2543E-03 -1.7804E-04 3.5559E-05 2.0808E-04 8.3100E-05 -5.9707E-06 -4.1594E-05 -8.7266E-06 S7 -1.3269E-01 1.4541E-02 -1.5492E-03 -7.5242E-04 7.5757E-05 -1.6420E-04 -3.3637E-05 -4.4986E-05 -9.2195E-06 S8 -1.8367E-01 1.4226E-02 7.4467E-04 -1.2746E-03 3.6881E-04 -3.4315E-04 -8.8808E-05 -1.0074E-04 1.0201E-05 S9 -2.5591E-02 -2.1561E-02 3.7117E-04 -1.4636E-03 -4.3836E-04 1.4267E-04 4.5500E-05 -1.3030E-05 5.0777E-06 S10 -1.5442E-01 2.2429E-02 -7.2092E-03 1.0727E-03 -1.3133E-03 5.7233E-04 1.8769E-04 5.4682E-05 1.5686E-05 S11 -1.0100E-01 -1.2119E-02 -4.2717E-04 -5.0638E-03 -8.5423E-04 -5.6112E-06 -1.5193E-04 -1.0018E-04 -2.0191E-05 S12 -3.3175E-01 -7.5479E-02 4.0575E-03 -2.1316E-03 -1.6327E-04 -2.9287E-04 -4.3807E-05 -8.5206E-05 4.4836E-05 S13 -1.7745E+00 5.5411E-01 -6.2809E-02 8.7527E-03 -9.4582E-03 2.5590E-03 1.8898E-04 -4.5661E-04 5.1822E-05 S14 -1.4714E+00 2.9569E-01 -1.1470E-02 2.8961E-02 -1.3190E-02 6.0605E-04 3.2071E-05 -2.7290E-04 -1.8202E-04

[0089] Table 2

[0090] Figure 2A The axial chromatic aberration curve of the optical imaging system of Example 1 is shown, which indicates the deviation of the convergent focus of light of different wavelengths after passing through the system. Figure 2B The astigmatism curve of the optical imaging system of Example 1 is shown, which represents the meridional field curvature and the sagittal field curvature. Figure 2C The distortion curve of the optical imaging system of Example 1 is shown, which represents the distortion value corresponding to different field angles. Figures 2A to 2C It can be seen that the optical imaging system provided in Example 1 can achieve good imaging quality.

[0091] Example 2

[0092] The following reference Figures 3 to 4C The optical imaging system according to Example 2 of the present application is described. In this embodiment and the following embodiments, some descriptions similar to Example 1 will be omitted for the sake of brevity. Figure 3 A structural schematic diagram of an optical imaging system according to Example 2 of the present application is shown.

[0093] like Figure 3 As shown, the optical imaging system includes, from the object side to the image side along the optical axis, a first lens E1, a second lens E2, a third lens E3, an aperture STO, a fourth lens E4, a fifth lens E5, a sixth lens E6, a seventh lens E7 and a filter E8.

[0094] The first lens E1 has positive optical power, with its object-side surface S1 being convex and its image-side surface S2 being concave. The second lens E2 has negative optical power, with its object-side surface S3 being convex and its image-side surface S4 being concave. 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 negative optical power, with its object-side surface S9 being convex and its image-side surface S10 being concave. The sixth lens E6 has positive optical power, with its object-side surface S11 being convex and its image-side surface S12 being concave. The seventh lens E7 has negative optical power, with its object-side surface S13 being convex and its image-side surface S14 being concave. The filter E8 has an object-side surface S15 and an image-side surface S16. The optical imaging system has an imaging surface S17 . Light from an object passes through the surfaces S1 to S16 in sequence and is finally imaged on the imaging surface S17 .

[0095] In Example 2, the effective focal length f of the optical imaging system is 4.00 mm, the on-axis distance TTL from the object-side surface S1 of the first lens E1 to the imaging surface S17 is 5.28 mm, the value ImgH of half the diagonal length of the effective pixel area on the imaging surface S17 is 3.28 mm, and the value Semi-FOV of half the maximum field of view is 40.0°.

[0096] Table 3 shows the basic parameters of the optical imaging system of Example 2, where the units of curvature radius, thickness / distance, and focal length are all in millimeters (mm). Table 4 shows the high-order coefficients of each aspheric mirror surface that can be used in Example 2, where the surface shape of each aspheric surface can be defined by formula (6) given in Example 1 above.

[0097]

[0098] Table 3

[0099]

[0100]

[0101] Table 4

[0102] Figure 4A The axial chromatic aberration curve of the optical imaging system of Example 2 is shown, which indicates the deviation of the convergent focus of light of different wavelengths after passing through the system. Figure 4B An astigmatism curve of the optical imaging system of Example 2 is shown, which indicates meridional field curvature and sagittal field curvature. Figure 4C The distortion curve of the optical imaging system of Example 2 is shown, which represents the distortion magnitude values ​​corresponding to different field angles. Figures 4A to 4C It can be seen that the optical imaging system provided in Example 2 can achieve good imaging quality.

[0103] Example 3

[0104] The following reference Figures 5 to 6C An optical imaging system according to Example 3 of the present application is described. Figure 5 A structural schematic diagram of an optical imaging system according to Example 3 of the present application is shown.

[0105] like Figure 5 As shown, the optical imaging system includes, from the object side to the image side along the optical axis, a first lens E1, a second lens E2, a third lens E3, an aperture STO, a fourth lens E4, a fifth lens E5, a sixth lens E6, a seventh lens E7 and a filter E8.

[0106] The first lens E1 has positive optical power, with its object-side surface S1 being convex and its image-side surface S2 being concave. The second lens E2 has negative optical power, with its object-side surface S3 being convex and its image-side surface S4 being concave. 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 negative optical power, with its object-side surface S9 being convex and its image-side surface S10 being concave. The sixth lens E6 has positive optical power, with its object-side surface S11 being convex and its image-side surface S12 being concave. The seventh lens E7 has negative optical power, with its object-side surface S13 being convex and its image-side surface S14 being concave. The filter E8 has an object-side surface S15 and an image-side surface S16. The optical imaging system has an imaging surface S17 . Light from an object passes through the surfaces S1 to S16 in sequence and is finally imaged on the imaging surface S17 .

[0107] In Example 3, the effective focal length f of the optical imaging system is 4.00 mm, the on-axis distance TTL from the object-side surface S1 of the first lens E1 to the imaging surface S17 is 5.31 mm, the value ImgH of half the diagonal length of the effective pixel area on the imaging surface S17 is 3.24 mm, and the value Semi-FOV of half the maximum field of view is 40.0°.

[0108] Table 5 shows the basic parameters of the optical imaging system of Example 3, where the units of curvature radius, thickness / distance, and focal length are all in millimeters (mm). Table 6 shows the high-order coefficients of each aspheric mirror surface that can be used in Example 3, where the surface shape of each aspheric surface can be defined by formula (6) given in Example 1 above.

[0109]

[0110]

[0111] Table 5

[0112] Face number A4 A6 A8 A10 A12 A14 A16 A18 A20 S1 -1.1296E-01 -1.9950E-02 1.0652E-02 1.2965E-03 -1.9621E-04 5.6337E-04 1.8897E-04 -6.4244E-06 -5.4621E-05 S2 6.6905E-02 -1.7940E-02 6.0250E-03 -1.1235E-03 4.3393E-04 4.3043E-04 1.7392E-04 8.9174E-05 -2.1456E-05 S3 -9.2328E-02 4.1681E-03 -5.1888E-03 -1.7122E-03 5.4583E-04 -3.3035E-04 2.3411E-05 1.7690E-04 3.3751E-05 S4 -7.9875E-02 8.2310E-03 -5.6710E-03 6.1828E-04 7.2180E-04 -7.0632E-04 -1.1901E-04 2.1873E-04 9.7900E-05 S5 1.2958E-01 8.4720E-03 -6.2013E-04 1.2430E-03 1.1798E-03 1.0128E-04 -3.1584E-05 5.3723E-05 4.8333E-05 S6 -8.7505E-03 3.4617E-03 2.8623E-04 2.8138E-04 1.6185E-04 4.0683E-05 -2.2882E-05 -2.4263E-05 -1.1293E-05 S7 -1.0011E-01 1.1202E-02 -7.8103E-04 -4.3401E-04 -9.0362E-05 -2.1537E-04 -1.0541E-04 -6.5784E-05 -1.4376E-05 S8 -1.4160E-01 1.0913E-02 1.6907E-03 -2.4802E-04 1.2133E-04 -3.6926E-04 -1.9376E-04 -1.1593E-04 -2.2220E-05 S9 -1.6914E-02 -1.6074E-02 1.8691E-03 -6.7430E-04 -6.1337E-06 1.0987E-04 6.9044E-05 7.5561E-07 4.4699E-08 S10 -1.1604E-01 2.1655E-02 -5.6697E-03 -5.1122E-04 -9.4733E-04 4.6961E-04 2.1015E-04 5.6383E-05 -4.3375E-06 S11 -5.3166E-02 1.2506E-03 -1.7521E-03 -4.0744E-03 -9.1270E-05 -4.7532E-05 -3.8286E-05 -7.8813E-05 -1.0658E-05 S12 -2.1566E-01 -5.8225E-02 2.4376E-03 -1.1647E-03 6.9261E-04 1.8108E-04 2.8142E-04 9.1823E-05 8.2312E-05 S13 -1.4721E+00 3.0318E-01 -2.0860E-02 9.8426E-03 -3.9440E-03 9.6343E-05 4.6877E-04 5.3310E-04 -2.5631E-04 S14 -1.3007E+00 2.2431E-01 -5.0727E-03 3.0311E-02 -8.9709E-03 -8.3584E-04 -8.0529E-04 4.5309E-04 -1.0451E-04

[0113] Table 6

[0114] Figure 6A The axial chromatic aberration curve of the optical imaging system of Example 3 is shown, which indicates the deviation of the convergent focus of light of different wavelengths after passing through the system. Figure 6B An astigmatism curve of the optical imaging system of Example 3 is shown, which indicates meridional field curvature and sagittal field curvature. Figure 6C The distortion curve of the optical imaging system of Example 3 is shown, which represents the distortion value corresponding to different field angles. Figures 6A to 6C It can be seen that the optical imaging system provided in Example 3 can achieve good imaging quality.

[0115] Example 4

[0116] The following reference Figures 7 to 8C An optical imaging system according to Example 4 of the present application is described. Figure 7 A structural schematic diagram of an optical imaging system according to Example 4 of the present application is shown.

[0117] like Figure 7 As shown, the optical imaging system includes, from the object side to the image side along the optical axis, a first lens E1, a second lens E2, a third lens E3, an aperture STO, a fourth lens E4, a fifth lens E5, a sixth lens E6, a seventh lens E7 and a filter E8.

[0118] The first lens E1 has positive focal power, with its object-side surface S1 being convex and its image-side surface S2 being concave. The second lens E2 has negative focal power, with its object-side surface S3 being convex and its image-side surface S4 being concave. The third lens E3 has positive focal power, with its object-side surface S5 being convex and its image-side surface S6 being convex. The fourth lens E4 has negative focal power, with its object-side surface S7 being convex and its image-side surface S8 being concave. The fifth lens E5 has negative focal power, with its object-side surface S9 being convex and its image-side surface S10 being concave. The sixth lens E6 has positive focal power, with its object-side surface S11 being convex and its image-side surface S12 being convex. The seventh lens E7 has negative focal power, with its object-side surface S13 being concave and its image-side surface S14 being concave. The filter E8 has an object-side surface S15 and an image-side surface S16. The optical imaging system has an imaging surface S17 . Light from an object passes through the surfaces S1 to S16 in sequence and is finally imaged on the imaging surface S17 .

[0119] In Example 4, the effective focal length f of the optical imaging system is 4.00 mm, the on-axis distance TTL from the object-side surface S1 of the first lens E1 to the imaging surface S17 is 5.54 mm, the value ImgH of half the diagonal length of the effective pixel area on the imaging surface S17 is 3.31 mm, and the value Semi-FOV of half the maximum field of view is 40.0°.

[0120] Table 7 shows the basic parameters of the optical imaging system of Example 4, where the units of curvature radius, thickness / distance, and focal length are all in millimeters (mm). Table 8 shows the high-order coefficients of each aspheric mirror surface that can be used in Example 4, where the surface shape of each aspheric surface can be defined by formula (6) given in Example 1 above.

[0121]

[0122] Table 7

[0123] Face number A4 A6 A8 A10 A12 A14 A16 A18 A20 S1 -1.6542E-01 -2.3248E-02 1.7902E-02 3.6786E-03 -8.3242E-04 8.7349E-04 5.3031E-04 4.8471E-05 -1.3299E-04 S2 1.1024E-01 -2.1744E-02 8.2575E-03 8.5644E-04 9.7329E-04 5.7933E-04 5.8707E-04 1.3909E-04 1.8923E-05 S3 -1.4053E-01 4.7904E-03 -8.8677E-03 1.9375E-04 2.0962E-03 -1.6995E-03 1.3417E-04 -5.8706E-05 7.2688E-05 S4 -1.1618E-01 8.0597E-03 -1.7965E-02 4.9226E-03 3.5337E-03 -3.4036E-03 -1.1729E-04 3.4746E-04 1.0504E-04 S5 2.4654E-01 1.9018E-02 -9.7312E-03 1.7965E-03 3.2858E-03 -4.9697E-04 -3.2677E-04 4.3579E-05 -7.3554E-05 S6 -8.3388E-03 6.2049E-03 1.7409E-04 -5.8953E-05 3.2733E-04 5.8278E-05 -1.2630E-05 -7.5182E-05 1.0307E-05 S7 -1.7439E-01 1.8691E-02 -2.2611E-03 -1.0361E-03 3.5281E-05 -2.9573E-04 -1.7287E-04 -9.8455E-05 -7.1211E-05 S8 -2.2912E-01 1.3208E-02 -1.0524E-03 -1.8505E-03 2.9023E-04 -1.0487E-03 -4.5044E-04 -2.5306E-04 -5.9013E-05 S9 -1.1116E-02 -2.2601E-02 -7.2725E-04 -6.5379E-04 -1.7812E-04 -3.0860E-04 -2.2747E-04 -3.7115E-05 -4.9422E-05 S10 -1.5351E-01 2.3443E-02 -7.7688E-03 1.4036E-03 -1.4705E-03 8.2009E-05 1.7936E-04 2.3583E-04 6.3826E-05 S11 -1.0441E-01 -2.0037E-02 -3.3338E-03 -3.2957E-03 -7.7277E-04 1.0089E-03 8.1804E-04 3.6046E-04 1.0961E-05 S12 -2.7749E-01 -6.0881E-02 1.3907E-02 2.3665E-03 -7.0235E-04 -1.0895E-03 5.3554E-04 4.9497E-04 3.8913E-04 S13 -1.9013E+00 5.6123E-01 -3.8641E-02 6.8451E-03 -1.5625E-02 1.5314E-03 3.7915E-04 3.5657E-04 -7.4551E-04 S14 -1.7210E+00 4.2421E-01 -5.2028E-02 2.8511E-02 -2.0563E-02 5.7575E-03 -1.5607E-03 2.5443E-04 -5.5333E-04

[0124] Table 8

[0125] Figure 8A The axial chromatic aberration curve of the optical imaging system of Example 4 is shown, which indicates the deviation of the convergent focus of light of different wavelengths after passing through the system. Figure 8B An astigmatism curve of the optical imaging system of Example 4 is shown, which indicates meridional field curvature and sagittal field curvature. Figure 8C The distortion curve of the optical imaging system of Example 4 is shown, which represents the distortion value corresponding to different field angles. Figures 8A to 8C It can be seen that the optical imaging system provided in Example 4 can achieve good imaging quality.

[0126] Example 5

[0127] The following reference Figures 9 to 10C An optical imaging system according to Example 5 of the present application is described. Figure 9 A structural schematic diagram of an optical imaging system according to Example 5 of the present application is shown.

[0128] like Figure 9 As shown, the optical imaging system includes, from the object side to the image side along the optical axis, a first lens E1, a second lens E2, a third lens E3, an aperture STO, a fourth lens E4, a fifth lens E5, a sixth lens E6, a seventh lens E7 and a filter E8.

[0129] The first lens E1 has positive focal power, with its object-side surface S1 being convex and its image-side surface S2 being concave. The second lens E2 has negative focal power, with its object-side surface S3 being convex and its image-side surface S4 being concave. The third lens E3 has positive focal power, with its object-side surface S5 being convex and its image-side surface S6 being convex. The fourth lens E4 has negative focal power, with its object-side surface S7 being convex and its image-side surface S8 being concave. The fifth lens E5 has negative focal power, with its object-side surface S9 being convex and its image-side surface S10 being concave. The sixth lens E6 has positive focal power, with its object-side surface S11 being convex and its image-side surface S12 being concave. The seventh lens E7 has negative focal power, with its object-side surface S13 being concave and its image-side surface S14 being concave. The filter E8 has an object-side surface S15 and an image-side surface S16. The optical imaging system has an imaging surface S17 . Light from an object passes through the surfaces S1 to S16 in sequence and is finally imaged on the imaging surface S17 .

[0130] In Example 5, the effective focal length f of the optical imaging system is 4.00 mm, the on-axis distance TTL from the object-side surface S1 of the first lens E1 to the imaging surface S17 is 5.29 mm, the value ImgH of half the diagonal length of the effective pixel area on the imaging surface S17 is 3.31 mm, and the value Semi-FOV of half the maximum field of view is 40.0°.

[0131] Table 9 shows the basic parameters of the optical imaging system of Example 5, where the units of curvature radius, thickness / distance, and focal length are all in millimeters (mm). Table 10 shows the high-order coefficients of each aspheric mirror surface that can be used in Example 5, where the surface shape of each aspheric surface can be defined by formula (6) given in Example 1 above.

[0132]

[0133] Table 9

[0134]

[0135]

[0136] Table 10

[0137] Figure 10A The axial chromatic aberration curve of the optical imaging system of Example 5 is shown, which indicates the deviation of the convergent focus of light of different wavelengths after passing through the system. Figure 10B An astigmatism curve of the optical imaging system of Example 5 is shown, which indicates meridional field curvature and sagittal field curvature. Figure 10C The distortion curve of the optical imaging system of Example 5 is shown, which represents the distortion magnitude values ​​corresponding to different field angles. Figures 10A to 10C It can be seen that the optical imaging system provided in Example 5 can achieve good imaging quality.

[0138] Example 6

[0139] The following reference Figures 11 to 12C An optical imaging system according to Example 6 of the present application is described. Figure 11 A structural schematic diagram of an optical imaging system according to Example 6 of the present application is shown.

[0140] like Figure 11 As shown, the optical imaging system includes, from the object side to the image side along the optical axis, a first lens E1, a second lens E2, a third lens E3, an aperture STO, a fourth lens E4, a fifth lens E5, a sixth lens E6, a seventh lens E7 and a filter E8.

[0141] The first lens E1 has positive focal power, with its object-side surface S1 being convex and its image-side surface S2 being concave. The second lens E2 has negative focal power, with its object-side surface S3 being convex and its image-side surface S4 being concave. The third lens E3 has positive focal power, with its object-side surface S5 being convex and its image-side surface S6 being convex. The fourth lens E4 has negative focal power, with its object-side surface S7 being convex and its image-side surface S8 being concave. The fifth lens E5 has negative focal power, with its object-side surface S9 being convex and its image-side surface S10 being concave. The sixth lens E6 has positive focal power, with its object-side surface S11 being convex and its image-side surface S12 being convex. The seventh lens E7 has negative focal power, with its object-side surface S13 being concave and its image-side surface S14 being concave. The filter E8 has an object-side surface S15 and an image-side surface S16. The optical imaging system has an imaging surface S17 . Light from an object passes through the surfaces S1 to S16 in sequence and is finally imaged on the imaging surface S17 .

[0142] In Example 6, the effective focal length f of the optical imaging system is 4.00 mm, the on-axis distance TTL from the object-side surface S1 of the first lens E1 to the imaging surface S17 is 5.47 mm, the value ImgH of half the diagonal length of the effective pixel area on the imaging surface S17 is 3.28 mm, and the value Semi-FOV of half the maximum field of view is 40.0°.

[0143] Table 11 shows the basic parameters of the optical imaging system of Example 6, where the units of curvature radius, thickness, and focal length are all in millimeters (mm). Table 12 shows the high-order coefficients of each aspheric mirror surface that can be used in Example 6, where the surface shape of each aspheric surface can be defined by formula (6) given in Example 1 above.

[0144]

[0145]

[0146] Table 11

[0147] Face number A4 A6 A8 A10 A12 A14 A16 A18 A20 S1 -1.4919E-01 -2.5824E-02 1.6304E-02 2.6457E-03 -1.3326E-03 6.4438E-04 7.7486E-04 4.1301E-06 -1.8254E-04 S2 1.0338E-01 -2.1370E-02 8.1790E-03 7.8627E-04 4.1908E-04 8.7243E-04 8.0163E-04 1.2189E-04 -3.5604E-05 S3 -1.1975E-01 6.9013E-03 -7.3295E-03 -4.3038E-04 2.1000E-03 -2.9102E-04 -3.2202E-04 -6.3211E-05 5.3502E-06 S4 -1.0685E-01 1.0260E-02 -1.1209E-02 1.5472E-03 2.7709E-03 -1.2773E-03 -8.5445E-04 2.1610E-04 1.6224E-04 S5 2.0105E-01 1.4730E-02 -3.6372E-03 1.5006E-03 2.5287E-03 4.7478E-04 -3.2679E-04 2.0266E-05 1.9188E-05 S6 -1.1920E-02 5.1040E-03 5.2688E-04 3.5016E-04 3.0601E-04 9.4256E-05 -1.8268E-05 -4.1345E-05 -6.5029E-06 S7 -1.5086E-01 1.7156E-02 -1.3462E-03 -8.4613E-04 1.0901E-04 -2.0503E-04 -7.2798E-05 -3.7880E-05 -2.9908E-05 S8 -1.8905E-01 1.2932E-02 9.5618E-04 -7.5730E-04 9.0028E-04 -2.8976E-04 -1.2156E-04 -9.1644E-05 -3.1971E-05 S9 -2.3041E-02 -2.0432E-02 3.8172E-05 -2.8847E-04 9.1442E-05 2.6621E-04 -8.9785E-05 1.8198E-05 -4.1574E-05 S10 -1.6719E-01 2.4292E-02 -5.9012E-03 1.1716E-03 -1.5430E-03 -2.0735E-05 -1.9890E-04 2.3194E-05 -2.1354E-05 S11 -8.5689E-02 -1.3485E-02 -2.4885E-03 -3.5563E-03 -1.2625E-03 1.3851E-05 -1.5108E-05 4.0593E-05 -6.0853E-05 S12 -3.0544E-01 -7.1837E-02 1.2986E-02 2.1714E-03 -1.8945E-04 -6.2676E-04 5.1335E-04 3.4732E-04 3.1448E-04 S13 -1.8352E+00 4.9806E-01 -2.4008E-02 6.5358E-03 -1.1413E-02 6.9550E-04 1.6192E-03 1.7317E-04 -5.1773E-04 S14 -1.7006E+00 4.1057E-01 -4.6346E-02 2.7679E-02 -1.8590E-02 3.2295E-03 -1.7132E-04 9.1330E-05 -3.7855E-04

[0148] Table 12

[0149] Figure 12A The axial chromatic aberration curve of the optical imaging system of Example 6 is shown, which indicates the deviation of the convergent focus of light of different wavelengths after passing through the system. Figure 12B An astigmatism curve of the optical imaging system of Example 6 is shown, which indicates meridional field curvature and sagittal field curvature. Figure 12C The distortion curve of the optical imaging system of Example 6 is shown, which represents the distortion value corresponding to different field angles. 12A to 12C It can be seen that the optical imaging system provided in Example 6 can achieve good imaging quality.

[0150] In summary, Examples 1 to 6 respectively satisfy the relationships shown in Table 13.

[0151]

[0152]

[0153] Table 13

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

[0155] The above description is merely a preferred embodiment of the present application and an illustration of the technical principles employed. Those skilled in the art should understand that the scope of protection provided in this application is not limited to the technical solutions formed by a specific combination of the above-mentioned technical features, but also encompasses other technical solutions formed by any combination of the above-mentioned technical features or their equivalents without departing from the concept of this application. For example, a technical solution formed by replacing the above-mentioned features with (but not limited to) technical features with similar functions disclosed in this application.

Claims

1. An optical imaging system, characterized in that Along the optical axis from the object side to the image side, they include: The first lens has positive refractive power, its object-side surface is convex and its image-side surface is concave; a second lens having negative optical power, the object-side surface of which is convex and the image-side surface of which is concave; The third lens has positive optical power, its object-side surface is convex, and its image-side surface is convex; a fourth lens element having negative optical power, whose object-side surface is convex and whose image-side surface is concave; a fifth lens element having negative optical power, whose object-side surface is convex and whose image-side surface is concave; a sixth lens element having positive optical power and a convex object-side surface; a seventh lens element having negative optical power and a concave image-side surface; The number of lenses having optical power in the optical imaging system is seven; The optical imaging system satisfies the following conditional formula: 1.55≤f / EPD≤1.90; 3.65≤CT6 / CT5≤5.53; -2.25≤R6 / R7≤-1.15; and -3.03≤SAG71 / SAG31≤-2.91; Among them, f is the effective focal length of the optical imaging system, EPD is the entrance pupil diameter of the optical imaging system, CT5 is the center thickness of the fifth lens on the optical axis, CT6 is the center thickness of the sixth lens on the optical axis, R6 is the radius of curvature of the image side surface of the third lens, R7 is the radius of curvature of the object side surface of the fourth lens, SAG71 is the on-axis distance from the intersection of the object side surface of the seventh lens and the optical axis to the effective radius vertex of the object side surface of the seventh lens, and SAG31 is the on-axis distance from the intersection of the object side surface of the third lens and the optical axis to the effective radius vertex of the object side surface of the third lens.

2. The optical imaging system according to claim 1, wherein: The effective focal length f2 of the second lens and the effective focal length f4 of the fourth lens satisfy 1.14≤f4 / f2≤1.

37.

3. The optical imaging system according to claim 2, wherein: The optical imaging system also satisfies the conditional formula: 1.58≤ET7 / (ET3+ET6)≤3.74; ET3 is the edge thickness of the third lens, ET6 is the edge thickness of the sixth lens, and ET7 is the edge thickness of the seventh lens.

4. The optical imaging system according to claim 1, wherein: The effective focal length f1 of the first lens and the effective focal length f3 of the third lens satisfy 1.16≤f1 / f3≤1.

73.

5. The optical imaging system according to claim 1, wherein: An effective focal length f6 of the sixth lens and a curvature radius R11 of the object-side surface of the sixth lens satisfy 1.59≤f6 / R11≤2.

14.

6. The optical imaging system according to claim 1, wherein: A center thickness CT1 of the first lens on the optical axis and a center thickness CT2 of the second lens on the optical axis satisfy 1.51≤CT1 / CT2≤1.

78.

7. The optical imaging system according to claim 1, wherein: A center thickness CT6 of the sixth lens on the optical axis and a center thickness CT7 of the seventh lens on the optical axis satisfy 2.07≤CT6 / CT7≤3.

29.

8. The optical imaging system according to claim 1, wherein: A distance T34 between the third lens and the fourth lens on the optical axis and a distance T67 between the sixth lens and the seventh lens on the optical axis satisfy 2.45≤T67 / T34≤3.

51.

9. The optical imaging system according to claim 1, wherein: A distance T12 between the first lens and the second lens on the optical axis, a distance T45 between the fourth lens and the fifth lens on the optical axis, and a distance T56 between the fifth lens and the sixth lens on the optical axis satisfy 2.71≤(T45+T56) / T12≤3.

23.

10. The optical imaging system according to claim 1, wherein: A curvature radius R2 of the image-side surface of the first lens and a curvature radius R3 of the object-side surface of the second lens satisfy 2.21≤(R2+R3) / (R2-R3)≤3.

27.

11. The optical imaging system according to claim 1, wherein: A curvature radius R11 of the object-side surface of the sixth lens and a curvature radius R14 of the image-side surface of the seventh lens satisfy 1.05≤R11 / R14≤1.

26.

12. The optical imaging system according to claim 1, wherein: A center thickness CT3 of the third lens on the optical axis and a center thickness CT4 of the fourth lens on the optical axis satisfy 3.08≤CT3 / CT4≤3.

96.

13. The optical imaging system according to claim 1, wherein: A combined focal length f45 of the fourth lens and the fifth lens and a combined focal length f123 of the first lens, the second lens, and the third lens satisfy -2.26≤f45 / f123≤-1.

95.

14. The optical imaging system according to any one of claims 1 to 13, characterized in that: The refractive index N2 of the second lens is greater than 1.60, the refractive index N4 of the fourth lens is greater than 1.60, and the refractive index N5 of the fifth lens is greater than 1.

60.

15. The optical imaging system according to any one of claims 1 to 13, characterized in that: The Abbe number V2 of the second lens is less than 25.0, the Abbe number V4 of the fourth lens is less than 25.0, and the Abbe number V5 of the fifth lens is less than 25.0.

Images