Patent Publication Number: US-2021181484-A1

Title: Optical imaging system

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This application claims benefit of priority to Chinese Patent Application No. 201911295487.X filed on Dec. 16, 2019 before the China National Intellectual Property Administration, the entire disclosure of which is incorporated herein by reference in its entity. 
     TECHNICAL FIELD 
     The present disclosure relates to the field of optical elements, and more specifically, relates to an optical imaging system. 
     BACKGROUND 
     A camera module is usually installed on the portable device, such as mobile phone, so that the mobile phone has camera function. The camera module is usually provided with a Charge-coupled Device (CCD) type image sensor or a Complementary Metal Oxide Semiconductor (CMOS) type image sensor, and is provided with an optical imaging system. The optical imaging system may collect the light on the object side, and the imaging light travels along the optical path of the optical imaging system and illuminates on the image sensor. The image sensor converts the light signal into an electrical signal to form image data. 
     In recent years, with the upgrading of the portable device and the development of image software functions and video software functions on the portable device, the hardware used in the portable device is constantly updated and developed. Also, it is expected that the pixel, image quality, resolution and other performance of the camera module applicable to the portable device will get better and better. For example, with the continuous advancement of CCD image sensor or CMOS image sensor technology, the pixel size on the chip continues to decrease and the number of pixels continues to increase. The performance of the optical imaging system suitable to the image sensor also needs to be higher and higher. Moreover, the user demands for the portable device have become more diverse. In addition to performance, such as high pixels, high resolution, and high relative brightness, the optical imaging system is also required to have a large field-of-view, so that the optical imaging system can clearly image the scene. 
     In order to meet the assembly requirements of the portable device and meet the imaging requirements, an optical imaging system that can simultaneously satisfy the characteristics of wide-angle, large aperture and high image quality, is required. 
     SUMMARY 
     The present disclosure provides an optical imaging system that is applicable to portable electronic products and at least solves or partially solves at least one of the above disadvantages of the prior art. 
     The present disclosure provides an optical imaging system which includes, sequentially from an object side to an image side along an 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 of the first lens to the seventh lens has refractive power. An object-side surface of the first lens is a concave surface, and an image-side surface thereof is a concave surface; an object-side surface of the second lens is a convex surface, and an image-side surface thereof is a convex surface; and an object-side surface of the third lens is a concave surface, and an image-side surface thereof is a convex surface. 
     In one embodiment, the object-side surface of the first lens to an image-side surface of the seventh lens may have at least one aspheric surface. 
     In one embodiment, an effective focal length f4 of the fourth lens and a total effective focal length f of the optical imaging system may satisfy −2.0&lt;f4/f&lt;−1.5. 
     In one embodiment, half of a maximal field-of-view Semi-FOV of the optical imaging system may satisfy Semi-FOV≥55°. 
     In one embodiment, an effective focal length f1 of the first lens and an effective focal length f2 of the second lens may satisfy −2.5&lt;f1/f2&lt;−2.0. 
     In one embodiment, an effective focal length f6 of the sixth lens and an effective focal length f7 of the seventh lens may satisfy −2.5&lt;f7/f6&lt;−1.0. 
     In one embodiment, a radius of curvature R 1  of the object-side surface of the first lens and a radius of curvature R 4  of the image-side surface of the second lens may satisfy 3.5&lt;R 1 /R 4 &lt;4.0. 
     In one embodiment, a radius of curvature R 2  of the image-side surface of the first lens and a radius of curvature R 3  of the object-side surface of the second lens may satisfy 1.0&lt;R 3 /R 2 &lt;1.5. 
     In one embodiment, a radius of curvature R 13  of an object-side surface of the seventh lens and a radius of curvature R 14  of an image-side surface of the seventh lens may satisfy 4.5&lt;(R 13 +R 14 )/(R 13 -R 14 )&lt;6.0. 
     In one embodiment, a radius of curvature R 8  of an image-side surface of the fourth lens, a radius of curvature R 9  of an object-side surface of the fifth lens and a radius of curvature R 11  of an object-side surface of the sixth lens may satisfy 1.0&lt;R 9 /(R 8 +R 11 )&lt;2.0. 
     In one embodiment, a center thickness CT 3  of the third lens along the optical axis, a center thickness CT 4  of the fourth lens along the optical axis and a center thickness CT 5  of the fifth lens along the optical axis may satisfy 1.5&lt;CT 5 /(CT 3 +CT 4 )&lt;2.0. 
     In one embodiment, a sum of center thicknesses ΣCT of the first lens to the seventh lens along the optical axis and a center thickness CT 2  of the second lens along the optical axis may satisfy 3.5&lt;ΣCT/CT 2 &lt;4.0. 
     In one embodiment, a sum of spaced intervals ΣAT between each two adjacent lenses of the first lens to the seventh lens along the optical axis and a spaced interval T 12  between the first lens and the second lens along the optical axis may satisfy 1.0&lt;ΣAT/T 12 &lt;2.0. 
     In one embodiment, a center thickness CT 6  of the sixth lens along the optical axis and a spaced interval T 67  between the sixth lens and the seventh lens along the optical axis may satisfy 1.0&lt;CT 6 /T 67 &lt;2.5. 
     In one embodiment, a refractive index N 3  of the third lens may satisfy N 3 &gt;1.60, a refractive index N 4  of the fourth lens may satisfy N 4 &gt;1.60, and a refractive index N 4  of the seventh lens may satisfy N 7 &gt;1.60. 
     In one embodiment, an Abbe number V3 of the third lens may satisfy V3&lt;25.0, and an Abbe number V4 of the fourth lens may satisfy V4&lt;25.0. 
     The present disclosure employs seven lenses, and the optical imaging system has at least one beneficial effect, such as wide angle, large aperture, and high image quality and the like, by rationally configuring the refractive power, the surface shape, the center thickness of each lens, and the on-axis spaced interval between the lenses and the like. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Other features, objects, and advantages of the present disclosure will become more apparent from the following detailed description of the non-limiting embodiments with reference to the accompanying drawings. In the drawings: 
         FIG. 1  illustrates a schematic structural view of an optical imaging system according to example 1 of the present disclosure; and  FIGS. 2A to 2C  illustrate a longitudinal aberration curve, an astigmatic curve, and a lateral color curve of the optical imaging system of the example 1, respectively. 
         FIG. 3  illustrates a schematic structural view of an optical imaging system according to example 2 of the present disclosure; and  FIGS. 4A to 4C  illustrate a longitudinal aberration curve, an astigmatic curve, and a lateral color curve of the optical imaging system of the example 2, respectively. 
         FIG. 5  illustrates a schematic structural view of an optical imaging system according to example 3 of the present disclosure; and  FIGS. 6A to 6C  illustrate a longitudinal aberration curve, an astigmatic curve, and a lateral color curve of the optical imaging system of the example 3, respectively. 
         FIG. 7  illustrates a schematic structural view of an optical imaging system according to example 4 of the present disclosure; and  FIGS. 8A to 8C  illustrate a longitudinal aberration curve, an astigmatic curve, and a lateral color curve of the optical imaging system of the example 4, respectively. 
         FIG. 9  illustrates a schematic structural view of an optical imaging system according to example 5 of the present disclosure; and  FIGS. 10A to 10C  illustrate a longitudinal aberration curve, an astigmatic curve, and a lateral color curve of the optical imaging system of the example 5, respectively. 
         FIG. 11  illustrates a schematic structural view of an optical imaging system according to example 6 of the present disclosure; and  FIGS. 12A to 12C  illustrate a longitudinal aberration curve, an astigmatic curve, and a lateral color curve of the optical imaging system of the example 6, respectively. 
         FIG. 13  illustrates a schematic structural view of an optical imaging system according to example 7 of the present disclosure; and  FIGS. 14A to 14C  illustrate a longitudinal aberration curve, an astigmatic curve, and a lateral color curve of the optical imaging system of the example 7, respectively. 
         FIG. 15  illustrates a schematic structural view of an optical imaging system according to example 8 of the present disclosure; and  FIGS. 16A to 16C  illustrate a longitudinal aberration curve, an astigmatic curve, and a lateral color curve of the optical imaging system of the example 8, respectively. 
     
    
    
     DETAILED DESCRIPTION OF EMBODIMENTS 
     For a better understanding of the present disclosure, various aspects of the present disclosure will be described in more detail with reference to the accompanying drawings. It should be understood that the detailed description is merely illustrative of the exemplary embodiments of the present disclosure and is not intended to limit the scope of the present disclosure 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. 
     It should be noted that in the present specification, the expressions such as first, second, third are used merely for distinguishing one feature from another, without indicating any limitation on the features. Thus, a first lens discussed below may also be referred to as a second lens or a third lens without departing from the teachings of the present disclosure. 
     In the accompanying drawings, the thickness, size and shape of the lens have been somewhat exaggerated for the convenience of explanation. In particular, shapes of spherical surfaces or aspheric surfaces shown in the accompanying drawings are shown by way of example. That is, shapes of the spherical surfaces or the aspheric surfaces are not limited to the shapes of the spherical surfaces or the aspheric surfaces shown in the accompanying drawings. The accompanying drawings are merely illustrative and not strictly drawn to scale. 
     Herein, the paraxial area refers to an area near the optical axis. If a surface of a lens is a convex surface and the position of the convex is not defined, it indicates that the surface of the lens is convex at least in the paraxial region; and if a surface of a lens is a concave surface and the position of the concave is not defined, it indicates that the surface of the lens is concave at least in the paraxial region. In each lens, the surface closest to the object is referred to as an object-side surface of the lens, and the surface closest to the imaging plane is referred to as an image-side surface of the lens. 
     It should be further understood that the terms “comprising,” “including,” “having,” “containing” and/or “contain,” when used in the specification, specify the presence of stated features, elements and/or components, but do not exclude the presence or addition of one or more other features, elements, components and/or combinations thereof. In addition, expressions, such as “at least one of,” when preceding a list of features, modify the entire list of features rather than an individual element in the list. Further, the use of “may,” when describing embodiments of the present disclosure, refers to “one or more embodiments of the present disclosure.” Also, the term “exemplary” is intended to refer to an example or illustration. 
     Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by those of ordinary skill in the art to which the present disclosure belongs. It will be further understood that terms, such as those defined in commonly used dictionaries, should be interpreted as having a meaning that is consistent with the meaning in the context of the relevant art and will not be interpreted in an idealized or overly formal sense, unless expressly so defined herein. 
     It should also be noted that, the examples in the present disclosure and the features in the examples may be combined with each other on a non-conflict basis. The present disclosure will be described in detail below with reference to the accompanying drawings and in combination with the examples. 
     The features, principles, and other aspects of the present disclosure are described in detail below. 
     An optical imaging system according to an exemplary embodiment of the present disclosure may include seven lenses having refractive power, which are a first lens, a second lens, a third lens, a fourth lens, a fifth lens, a sixth lens and a seventh lens. The seven lenses are arranged sequentially from an object side to an image side along an optical axis. Among the first lens to the seventh lens, there may be an air interval between each two adjacent lenses. 
     In an exemplary embodiment, the first lens has positive or negative refractive power, an object-side surface thereof may be a concave surface, and an image-side surface thereof may be a concave surface; the second lens has positive or negative refractive power, an object-side surface thereof may be a convex surface, and an image-side surface thereof may be a convex surface; the third lens has positive or negative refractive power, an object-side surface thereof may be a concave surface, and an image-side surface thereof may be a convex surface; the fourth lens has positive or negative refractive power; the fifth lens has positive or negative refractive power; the sixth lens has positive or negative refractive power; and the seventh lens has positive or negative refractive power. The low-order aberrations of the system are effectively compensated by rationally controlling the positive or negative distribution of the refractive power and the surface curvature of each component in the system. By rationally configuring the shape of the first lens, it is possible to ensure that the first lens has good workability and enable the optical imaging system to have a relative large field-of-view. By rationally configuring the shape of the second lens, the tolerance sensitivity of the optical imaging system may be effectively reduced. By rationally configuring the shape of the third lens, it is beneficial to reduce the astigmatic of the optical imaging system. 
     In an exemplary embodiment, a refractive index N 3  of the third lens may satisfy N 3 &gt;1.60, a refractive index N 4  of the fourth lens may satisfy N 4 &gt;1.60, and a refractive index N 7  of the seventh lens may satisfy N 7 &gt;1.60. More specifically, the refractive index N 3  of the third lens, the refractive index N 4  of the fourth lens, and the refractive index N 7  of the seventh lens may be greater than 1.62, respectively. The third lens, the fourth lens and the seventh lens are made of materials with high refractive index, which is beneficial to correct the off-axis coma and astigmatic of the optical imaging system, and improve the image quality in the external field-of-view. 
     In an exemplary embodiment, an Abbe number V3 of the third lens may satisfy V3&lt;25.0, and an Abbe number V4 of the fourth lens may satisfy V4&lt;25.0. More specifically, the Abbe number V3 of the third lens and the Abbe number V4 of the fourth lens may be less than 22, respectively. By limiting the Abbe number of the third lens and the Abbe number of the fourth lens satisfy the aforementioned conditional expressions, it is beneficial to correct the off-axis coma and astigmatic of the optical imaging system, thereby improving the image quality in the external field-of-view. 
     In an exemplary embodiment, the optical imaging system according to the present disclosure may satisfy: Semi-FOV≥55°, where Semi-FOV is half of a maximal field-of-view of the optical imaging system. More specifically, Semi-FOV may satisfy: 55≤Semi-FOV≤85°. By properly configuring the maximal field-of-view of the optical imaging system, the optical imaging system may obtain a larger field-of-view and improve the ability of the optical imaging system to collect the information at the object side. 
     In an exemplary embodiment, the optical imaging system according to the present disclosure may satisfy: −2.0&lt;f4/f&lt;−1.5, where f4 is an effective focal length of the fourth lens, and f is a total effective focal length of the optical imaging system. More specifically, f4 and f may satisfy: −1.80&lt;f4/f&lt;−1.65. By setting the fourth lens to have negative refractive power and controlling its magnitude, the fourth lens assumes the negative refractive power required by the optical imaging system. Moreover, by controlling the ratio of the effective focal length of the fourth lens to the total effective focal length, it is beneficial to control the spherical aberration contributed by the fourth lens in an appropriate range, so as to ensure that the lenses on the image side of the fourth lens may properly correct the negative spherical aberration contributed by the fourth lens, and thus the on-axis field of the optical imaging system may stably have better image quality. 
     In an exemplary embodiment, the optical imaging system according to the present disclosure may satisfy: −2.5&lt;f1/f2&lt;−2.0, where f1 is an effective focal length of the first lens, and f2 is an effective focal length of the second lens. More specifically, f1 and f2 may satisfy: −2.20&lt;f1/f2&lt;−2.05. By controlling the ratio of the effective focal length of the first lens to the effective focal length of the second lens, it is beneficial to make the refractive power of the first lens and the refractive power of the second lens cooperate with each other, and thus to compensate the off-axis aberrations of the optical imaging system. 
     In an exemplary embodiment, the optical imaging system according to the present disclosure may satisfy: −2.5&lt;f7/f6&lt;−1.0, where f6 is an effective focal length of the sixth lens, and f7 is an effective focal length of the seventh lens. More specifically, f6 and f7 may satisfy: −2.10&lt;f7/f6&lt;−1.20. By reasonably limiting the refractive power of the sixth lens and the refractive power of the seventh lens, it is beneficial to compensate the off-axis aberrations of the optical imaging system. 
     In an exemplary embodiment, the optical imaging system according to the present disclosure may satisfy: 3.5&lt;R 1 /R 4 &lt;4.0, where R 1  is a radius of curvature of the object-side surface of the first lens, and R 4  is a radius of curvature of the image-side surface of the second lens. More specifically, R 1  and R 4  may satisfy: 3.55&lt;R 1 /R 4 &lt;0. By controlling the ratio of the radius of curvature of the object-side surface of the first lens to the radius of curvature of the image-side surface of the second lens, the optical imaging system may better achieve the deflection of the optical path. 
     In an exemplary embodiment, the optical imaging system according to the present disclosure may satisfy: 1.0&lt;R 3 /R 2 &lt;5, where R 2  is a radius of curvature of the image-side surface of the first lens, and R 3  is a radius of curvature of the object-side surface of the second lens. More specifically, R 2  and R 3  may satisfy: 1.01&lt;R 3 /R 2 &lt;1.10. By controlling the ratio of the radius of curvature of the object-side surface of the second lens to the radius of curvature of the image-side surface of the first lens, it is beneficial to better control the total deflection angle of the edge field at the two surfaces in the desired range, and effectively reduce the sensitivity of the optical imaging system. When the four surfaces of the first lens and the second lens are defined at the same time, it is beneficial to better deflect the optical path. 
     In an exemplary embodiment, the optical imaging system according to the present disclosure may satisfy: 4.5&lt;(R 13 +R 14 )/(R 13 -R 14 )&lt;6.0, where R 13  is a radius of curvature of an object-side surface of the seventh lens, and R 14  is a radius of curvature of an image-side surface of the seventh lens. More specifically, R 13  and R 14  may satisfy: 4.65&lt;(R 13 +R 14 )/(R 13 −R 14 )&lt;5.80. The coordination of the object-side surface of the seventh lens and the image-side surface of the seventh lens is beneficial to reducing the coma in the on-axis field of the optical imaging system and the coma in the off-axis field of the optical imaging system, thereby enabling the optical imaging system to have good image quality. 
     In an exemplary embodiment, the optical imaging system according to the present disclosure may satisfy: 1.0&lt;R 9 /(R 8 +R 11 )&lt;2.0, where R 8  is a radius of curvature of an image-side surface of the fourth lens, R 9  is a radius of curvature of an object-side surface of the fifth lens, and R 11  is a radius of curvature of an object-side surface of the sixth lens. More specifically, R 8 , R 9  and R 11  may satisfy: 1.20&lt;R 9 /(R 8 +R 11 )&lt;1.75. By rationally configuring the radius of curvature of the image-side surface of the fourth lens, the radius of curvature of the object-side surface of the fifth lens and the radius of curvature of the object-side surface of the sixth lens, it is possible to ensure that the chief ray angle (CRA) of the optical imaging system matches the photosensitive chip. In addition, the field curvature of the optical imaging system may be corrected, and each field-of-view of the optical imaging system may have better image clarity. 
     In an exemplary embodiment, the optical imaging system according to the present disclosure may satisfy: 1.5&lt;CT 5 /(CT 3 +CT 4 )&lt;2.0, where CT 3  is a center thickness of the third lens along the optical axis, CT 4  is a center thickness of the fourth lens along the optical axis, and CT 5  is a center thickness of the fifth lens along the optical axis. More specifically, CT 3 , CT 4  and CT 5  may satisfy: 1.80&lt;CT 5 /(CT 3 +CT 4 )&lt;1.90. By rationally configuring the center thickness of the third lens, the center thickness of the fourth lens and the center thickness of the fifth lens, the three lenses may be easily obtained by injection molding, so as to improve the workability of the optical imaging system. In addition, the better image quality of the optical imaging system is ensured. 
     In an exemplary embodiment, the optical imaging system according to the present disclosure may satisfy: 3.5&lt;ΣCT/CT 2 &lt;4.0, where ΣCT is a sum of center thicknesses of the first lens to the seventh lens along the optical axis, and CT 2  is a center thickness of the second lens along the optical axis. As an example, ΣCT=CT 1 +CT 2 +CT 3 +CT 4 +CT 5 +CT 6 +CT 7 . More specifically, ΣCT and CT 2  may satisfy: 3.52&lt;ΣCT/CT 2 &lt;3.76. By properly controlling the relationship between the thickness of the second lens and the sum of the thicknesses of the lenses of the optical imaging system, the shape of the second lens may be effectively restricted, and the range of residual distortion after compensation may be better controlled, so that the optical imaging system has a good distortion performance. 
     In an exemplary embodiment, the optical imaging system according to the present disclosure may satisfy: 1.0&lt;ΣAT/T 12 &lt;2.0, where ΣAT is a sum of spaced intervals between each two adjacent lenses of the first lens to the seventh lens along the optical axis, and T 12  is a spaced interval between the first lens and the second lens along the optical axis. As an example, ΣAT=T 12 +T 23 +T 34 +T 45 +T 56 +T 67 . More specifically, ΣAT and T 12  may satisfy: 1.20&lt;ΣAT/T 12 &lt;1.85. By properly controlling the ratio of the sum of air intervals between each two adjacent lenses from the first lens to the lens closest to the imaging plane of the optical imaging system to the air interval between the first lens and the second lens, the interval sensitivity of the optical imaging system may be effectively reduced, and the field curvature of the optical imaging system may be corrected. 
     In an exemplary embodiment, the optical imaging system according to the present disclosure may satisfy: 1.0&lt;CT 6 /T 67 &lt;2.5, where CT 6  is a center thickness of the sixth lens along the optical axis, and T 67  is a spaced interval between the sixth lens and the seventh lens along the optical axis. More specifically, CT 6  and T 67  may satisfy: 1.40&lt;CT 6 /T 67 &lt;2.20. By constraining the center thickness of the sixth lens along the optical axis and the air interval at the image side of the sixth lens, the field curvature and distortion of the optical imaging system may be effectively controlled, thereby improving the image quality of the optical imaging system. 
     In an exemplary embodiment, the above optical imaging system may further include a stop. The stop may be disposed at an appropriate position as required, for example, between the object side and the first lens or between the first lens and the second lens. Optionally, the above optical imaging system may further include an optical filter for correcting the color deviation and/or a protective glass for protecting the photosensitive element located on an imaging plane. 
     The optical imaging system according to the above embodiments of the present disclosure may employ a plurality of lenses, such as seven lenses as described above. By properly configuring the refractive power of each lens, the surface shape, the center thickness of each lens, and spaced intervals along the optical axis between the lenses, the size and the sensitivity of the imaging system may be effectively reduced, and the workability of the imaging system may be improved, such that the optical imaging system is more advantageous for production processing and may be applied to portable electronic products. At the same time, the optical imaging system of the present disclosure also has excellent optical performances, such as wide angle, large aperture, high resolution, and high image quality. 
     In the embodiments of the present disclosure, at least one of the surfaces of lenses is aspheric, that is, at least one of the object-side surface of the first lens to the image-side surface of the seventh lens is aspheric. The aspheric lens is characterized by a continuous change in curvature from the center of the lens to the periphery of the lens. Unlike a spherical lens having a constant curvature from the center of the lens to the periphery of the lens, the aspheric lens has a better curvature radius characteristic, and has the advantages of improving distortion aberration and improving astigmatic aberration. With aspheric lens, the aberrations that occur during imaging may be eliminated as much as possible, and thus improving the image quality. Optionally, at least one of the object-side surface and the image-side surface of each of the first lens, the second lens, the third lens, the fourth lens, the fifth lens, the sixth lens and the seventh lens is aspheric. Optionally, the surfaces of the first lens and the second lens are aspheric. Optionally, the object-side surface and the image-side surface of each of the first lens, the second lens, the third lens, the fourth lens, the fifth lens, the sixth lens and the seventh lens are aspheric. 
     However, it will be understood by those skilled in the art that the number of lenses constituting the optical imaging system may be varied to achieve the various results and advantages described in this specification without departing from the technical solution claimed by the present disclosure. For example, although the embodiment is described by taking seven lenses as an example, the optical imaging system is not limited to include seven lenses. The optical imaging system may also include other numbers of lenses if desired. 
     Some specific examples of an optical imaging system applicable to the above embodiment will be further described below with reference to the accompanying drawings. 
     EXAMPLE 1 
     An optical imaging system according to example 1 of the present disclosure is described below with reference to  FIG. 1  to  FIG. 2C .  FIG. 1  shows a schematic structural view of the optical imaging system according to example 1 of the present disclosure. 
     As shown in  FIG. 1 , the optical imaging system includes a first lens E 1 , a stop STO, a second lens E 2 , a third lens E 3 , a fourth lens E 4 , a fifth lens E 5 , a sixth lens E 6 , a seventh lens E 7  and an optical filter E 8 , which are sequentially arranged from an object side to an image side along an optical axis. 
     The first lens E 1  has negative refractive power, an object-side surface S 1  thereof is a concave surface, and an image-side surface S 2  thereof is a concave surface. The second lens E 2  has positive refractive power, an object-side surface S 3  thereof is a convex surface, and an image-side surface S 4  thereof is a convex surface. The third lens E 3  has negative refractive power, an object-side surface S 5  thereof is a concave surface, and an image-side surface S 6  thereof is a convex surface. The fourth lens E 4  has negative refractive power, an object-side surface S 7  thereof is a convex surface, and an image-side surface S 8  thereof is a concave surface. The fifth lens E 5  has positive refractive power, an object-side surface S 9  thereof is a convex surface, and an image-side surface S 10  thereof is a convex surface. The sixth lens E 6  has positive refractive power, an object-side surface S 11  thereof is a convex surface, and an image-side surface S 12  thereof is a convex surface. The seventh lens E 7  has negative refractive power, an object-side surface S 13  thereof is a convex surface, and an image-side surface S 14  thereof is a concave surface. The optical filter E 8  has an object-side surface S 15  and an image-side surface S 16 . The optical imaging system has an imaging plane S 17 , and light from an object sequentially passes through the respective surfaces S 1  to S 16  and is finally imaged on the imaging plane S 17 . 
     Table 1 is a table illustrating basic parameters of the optical imaging system of example 1, wherein the units for the radius of curvature, the thickness/distance and the focal length are millimeter (mm). 
     
       
         
           
               
               
               
             
               
                   
                 TABLE 1 
               
             
            
               
                   
                   
               
               
                   
                 Material 
                   
               
            
           
           
               
               
               
               
               
               
               
               
            
               
                 Surface 
                 Surface 
                 Radius of 
                 Thickness/ 
                 Refractive 
                 Abbe 
                 Focal 
                 Conic 
               
               
                 number 
                 type 
                 curvature 
                 Distance 
                 index 
                 number 
                 length 
                 coefficient 
               
               
                   
               
            
           
           
               
               
               
               
               
               
               
               
            
               
                 OBJ 
                 Spherical 
                 Infinite 
                 400.0000 
                   
                   
                   
                   
               
               
                 S1 
                 Aspheric 
                 −4.4618 
                 0.4631 
                 1.55 
                 56.1 
                 −3.98 
                 −48.8831 
               
               
                 S2 
                 Aspheric 
                 4.3816 
                 1.0129 
                   
                   
                   
                 −17.8267 
               
               
                 STO 
                 Spherical 
                 Infinite 
                 −0.0353 
               
               
                 S3 
                 Aspheric 
                 4.6075 
                 1.0597 
                 1.55 
                 56.1 
                 1.88 
                 26.1063 
               
               
                 S4 
                 Aspheric 
                 −1.2154 
                 0.0500 
                   
                   
                   
                 −1.5694 
               
               
                 S5 
                 Aspheric 
                 −10.3178 
                 0.2500 
                 1.68 
                 19.2 
                 −95.20 
                 89.7670 
               
               
                 S6 
                 Aspheric 
                 −12.4026 
                 0.0350 
                   
                   
                   
                 90.0000 
               
               
                 S7 
                 Aspheric 
                 8.5633 
                 0.2300 
                 1.67 
                 20.4 
                 −3.42 
                 34.4847 
               
               
                 S8 
                 Aspheric 
                 1.7818 
                 0.1168 
                   
                   
                   
                 −18.1974 
               
               
                 S9 
                 Aspheric 
                 6.2242 
                 0.8846 
                 1.55 
                 56.1 
                 8.06 
                 10.9489 
               
               
                 S10 
                 Aspheric 
                 −14.2444 
                 0.2227 
                   
                   
                   
                 90.0000 
               
               
                 S11 
                 Aspheric 
                 2.8762 
                 0.5565 
                 1.55 
                 56.1 
                 4.13 
                 −2.4443 
               
               
                 S12 
                 Aspheric 
                 −9.7207 
                 0.3036 
                   
                   
                   
                 −35.3621 
               
               
                 S13 
                 Aspheric 
                 1.1003 
                 0.4000 
                 1.64 
                 56.1 
                 −5.39 
                 −7.3940 
               
               
                 S14 
                 Aspheric 
                 0.7167 
                 0.4105 
                   
                   
                   
                 −3.6067 
               
               
                 S15 
                 Spherical 
                 Infinite 
                 0.1106 
                 1.62 
                 64.2 
               
               
                 S16 
                 Spherical 
                 Infinite 
                 0.3320 
               
               
                 S17 
                 Spherical 
                 Infinite 
               
               
                   
               
            
           
         
       
     
     In example 1, a total effective focal length f of the optical imaging system is 1.97 mm, an aperture number Fno of the optical imaging system is 1.70, an on-axis distance TTL from the object-side surface S 1  of the first lens E 1  to the imaging plane S 17  is 6.40 mm, half of a diagonal length ImgH of an effective pixel area on the imaging plane S 17  is 3.07 mm, and half of a maximal field-of-view Semi-FOV is 80.0°. 
     In example 1, the object-side surface and the image-side surface of any one of the first lens E 1  to the seventh lens E 7  are aspheric. The surface shape x of each aspheric lens may be defined by using, but not limited to, the following aspheric formula: 
     
       
         
           
             
               
                 
                   x 
                   = 
                   
                     
                       
                         ch 
                         2 
                       
                       
                         1 
                         + 
                         
                           
                             1 
                             - 
                             
                               
                                 ( 
                                 
                                   k 
                                   + 
                                   1 
                                 
                                 ) 
                               
                                
                               
                                 c 
                                 2 
                               
                                
                               
                                 h 
                                 2 
                               
                             
                           
                         
                       
                     
                     + 
                     
                       Σ 
                        
                       
                           
                       
                        
                       
                         Aih 
                         i 
                       
                     
                   
                 
               
               
                 
                   ( 
                   1 
                   ) 
                 
               
             
           
         
       
     
     Where, x is the sag—the axis-component of the displacement of the surface from the aspheric vertex, when the surface is at height h from the optical axis; c is a paraxial curvature of the aspheric surface, c=1/R (that is, the paraxial curvature c is reciprocal of the radius of curvature R in the above Table 1); k is a conic coefficient; Ai is a correction coefficient for the i-th order of the aspheric surface. Table 2 below shows high-order coefficients A 4 , A 6 , A 8 , A 10 , A 12 , A 14 , A 16 , A 18  and A 20  applicable to each aspheric surface S 1  to S 14  in example 1. 
     
       
         
           
               
               
               
               
               
               
             
               
                 TABLE 2 
               
               
                   
               
             
            
               
                 Surface 
                   
                   
                   
                   
                   
               
               
                 number 
                 A4 
                 A6 
                 A8 
                 A10 
                 A12 
               
               
                   
               
               
                 S1 
                  5.1470E−01 
                 −9.6605E−02 
                 1.3971E−02 
                 −4.3960E−03 
                 1.7240E−03 
               
               
                 S2 
                  2.9078E−01 
                 −4.5473E−04 
                 3.0262E−03 
                 −1.0892E−04 
                 −4.7303E−06  
               
               
                 S3 
                 −3.8998E−02 
                 −5.3589E−03 
                 −9.1690E−04  
                 −1.5765E−04 
                 −3.7133E−05  
               
               
                 S4 
                 −1.7346E−02 
                 −1.1575E−02 
                 2.0257E−03 
                 −8.9401E−04 
                 3.4000E−04 
               
               
                 S5 
                 −2.4607E−02 
                 −5.3346E−03 
                 9.1647E−03 
                 −5.1080E−04 
                 4.5896E−04 
               
               
                 S6 
                 −8.4000E−03 
                 −9.6300E−03 
                 9.8461E−03 
                  4.4490E−05 
                 2.7024E−04 
               
               
                 S7 
                 −1.0360E−01 
                  9.6232E−03 
                 4.0024E−03 
                 −1.1988E−04 
                 −3.0032E−04  
               
               
                 S8 
                  1.5713E−02 
                 −6.6345E−03 
                 1.7486E−03 
                 −1.6779E−03 
                 3.5531E−04 
               
               
                 S9 
                  4.1373E−03 
                 −8.5409E−03 
                 2.7910E−03 
                 −1.2411E−05 
                 2.1686E−04 
               
               
                 S10 
                 −3.2035E−01 
                  3.7432E−02 
                 1.0568E−02 
                  3.2219E−03 
                 4.9027E−03 
               
               
                 S11 
                  4.9713E−01 
                 −7.6347E−02 
                 1.7302E−02 
                 −4.9401E−03 
                 5.1302E−03 
               
               
                 S12 
                 −1.3020E−01 
                  4.5125E−02 
                 2.3628E−02 
                 −1.4560E−03 
                 7.8283E−05 
               
               
                 S13 
                 −1.4545E+00 
                  3.0626E−01 
                 −6.7329E−04  
                 −6.6878E−04 
                 −9.0549E−03  
               
               
                 S14 
                 −1.2567E+00 
                  2.1685E−01 
                 −7.3456E−02  
                  3.2497E−02 
                 −8.7027E−03  
               
               
                   
               
            
           
           
               
               
               
               
               
               
            
               
                   
                 Surface 
                   
                   
                   
                   
               
               
                   
                 number 
                 A14 
                 A16 
                 A18 
                 A20 
               
               
                   
                   
               
               
                   
                 S1 
                 −4.0231E−04 
                 1.3085E−04 
                 −5.5374E−05 
                 1.0130E−05 
               
               
                   
                 S2 
                  6.0360E−05 
                 −1.2500E−05  
                  2.7057E−05 
                 −3.5131E−06  
               
               
                   
                 S3 
                 −1.3026E−05 
                 −9.6888E−06  
                 −2.1428E−06 
                 −3.1395E−06  
               
               
                   
                 S4 
                 −1.5208E−04 
                 5.4205E−05 
                 −1.2023E−05 
                 9.9513E−07 
               
               
                   
                 S5 
                 −3.8529E−04 
                 1.4995E−04 
                 −2.6945E−05 
                 1.7052E−05 
               
               
                   
                 S6 
                 −3.1343E−04 
                 5.0128E−05 
                 −6.8059E−06 
                 2.5375E−06 
               
               
                   
                 S7 
                 −1.6811E−04 
                 4.8081E−05 
                  1.3673E−05 
                 −5.7853E−06  
               
               
                   
                 S8 
                 −2.0914E−04 
                 1.8276E−05 
                 −1.5210E−05 
                 1.3625E−06 
               
               
                   
                 S9 
                 −3.9256E−05 
                 −1.1288E−06  
                  4.2687E−05 
                 2.1941E−06 
               
               
                   
                 S10 
                  9.9641E−04 
                 6.3392E−04 
                  1.7663E−04 
                 7.8348E−05 
               
               
                   
                 S11 
                  1.8246E−03 
                 −3.9832E−04  
                 −5.2298E−04 
                 5.3113E−05 
               
               
                   
                 S12 
                  2.7784E−03 
                 4.3598E−03 
                  5.9953E−04 
                 1.7862E−04 
               
               
                   
                 S13 
                  1.0724E−03 
                 −5.7523E−04  
                 −6.7920E−04 
                 5.3074E−04 
               
               
                   
                 S14 
                  3.7867E−03 
                 −1.4719E−03  
                  3.0681E−04 
                 −3.1088E−05  
               
               
                   
                   
               
            
           
         
       
     
       FIG. 2A  illustrates a longitudinal aberration curve of the optical imaging system according to example 1, representing deviations of focal points converged by light of different wavelengths after passing through the system.  FIG. 2B  illustrates an astigmatic curve of the optical imaging system according to example 1, representing a curvature of a tangential plane and a curvature of a sagittal plane.  FIG. 2C  illustrates a lateral color curve of the optical imaging system according to example 1, representing deviations of different image heights on an imaging plane after light passes through the system. It can be seen from  FIG. 2A  to  FIG. 2C  that the optical imaging system provided in example 1 may achieve good image quality. 
     EXAMPLE 2 
     An optical imaging system according to example 2 of the present disclosure is described below with reference to  FIG. 3  to  FIG. 4C . In this example and the following examples, for the purpose of brevity, the description of parts similar to those in example 1 will be omitted.  FIG. 3  shows a schematic structural view of the optical imaging system according to example 2 of the present disclosure. 
     As shown in  FIG. 3 , the optical imaging system includes a first lens E 1 , a stop STO, a second lens E 2 , a third lens E 3 , a fourth lens E 4 , a fifth lens E 5 , a sixth lens E 6 , a seventh lens E 7  and an optical filter E 8 , which are sequentially arranged from an object side to an image side along an optical axis. 
     The first lens E 1  has negative refractive power, an object-side surface S 1  thereof is a concave surface, and an image-side surface S 2  thereof is a concave surface. The second lens E 2  has positive refractive power, an object-side surface S 3  thereof is a convex surface, and an image-side surface S 4  thereof is a convex surface. The third lens E 3  has negative refractive power, an object-side surface S 5  thereof is a concave surface, and an image-side surface S 6  thereof is a convex surface. The fourth lens E 4  has negative refractive power, an object-side surface S 7  thereof is a convex surface, and an image-side surface S 8  thereof is a concave surface. The fifth lens E 5  has positive refractive power, an object-side surface S 9  thereof is a convex surface, and an image-side surface S 10  thereof is a convex surface. The sixth lens E 6  has positive refractive power, an object-side surface S 11  thereof is a convex surface, and an image-side surface S 12  thereof is a convex surface. The seventh lens E 7  has negative refractive power, an object-side surface S 13  thereof is a convex surface, and an image-side surface S 14  thereof is a concave surface. The optical filter E 8  has an object-side surface S 15  and an image-side surface S 16 . The optical imaging system has an imaging plane S 17 , and light from an object sequentially passes through the respective surfaces S 1  to S 16  and is finally imaged on the imaging plane S 17 . 
     In example 2, a total effective focal length f of the optical imaging system is 1.97 mm, an aperture number Fno of the optical imaging system is 1.70, an on-axis distance TTL from the object-side surface S 1  of the first lens E 1  to the imaging plane S 17  is 6.47 mm, half of a diagonal length ImgH of an effective pixel area on the imaging plane S 17  is 3.07 mm, and half of a maximal field-of-view Semi-FOV is 82.4°. 
     Table 3 is a table illustrating basic parameters of the optical imaging system of example 2, wherein the units for the radius of curvature, the thickness/distance and the focal length are millimeter (mm). Table 4 shows high-order coefficients applicable to each aspheric surface in example 2, wherein the surface shape of each aspheric surface may be defined by the formula (1) given in the above example 1. 
     
       
         
           
               
               
               
             
               
                   
                 TABLE 3 
               
             
            
               
                   
                   
               
               
                   
                 Material 
                   
               
            
           
           
               
               
               
               
               
               
               
               
            
               
                 Surface 
                 Surface 
                 Radius of 
                 Thickness/ 
                 Refractive 
                 Abbe 
                 Focal 
                 Conic 
               
               
                 number 
                 type 
                 curvature 
                 Distance 
                 index 
                 number 
                 length 
                 coefficient 
               
               
                   
               
            
           
           
               
               
               
               
               
               
               
               
            
               
                 OBJ 
                 Spherical 
                 Infinite 
                 400.0000 
                   
                   
                   
                   
               
               
                 S1 
                 Aspheric 
                 −4.4348 
                 0.4631 
                 1.55 
                 56.1 
                 −3.99 
                 −48.8831 
               
               
                 S2 
                 Aspheric 
                 4.4301 
                 1.0180 
                   
                   
                   
                 −13.3282 
               
               
                 STO 
                 Spherical 
                 Infinite 
                 −0.0370 
               
               
                 S3 
                 Aspheric 
                 4.6306 
                 1.0443 
                 1.55 
                 56.1 
                 1.88 
                 26.1063 
               
               
                 S4 
                 Aspheric 
                 −1.2146 
                 0.0500 
                   
                   
                   
                 −1.7000 
               
               
                 S5 
                 Aspheric 
                 −10.3114 
                 0.2596 
                 1.68 
                 19.2 
                 −91.39 
                 89.8576 
               
               
                 S6 
                 Aspheric 
                 −12.4974 
                 0.0350 
                   
                   
                   
                 90.0000 
               
               
                 S7 
                 Aspheric 
                 −65.0000 
                 0.2300 
                 1.67 
                 20.4 
                 −3.34 
                 −90.0000 
               
               
                 S8 
                 Aspheric 
                 2.3107 
                 0.1174 
                   
                   
                   
                 −17.9586 
               
               
                 S9 
                 Aspheric 
                 6.2823 
                 0.8890 
                 1.55 
                 56.1 
                 8.14 
                 4.3256 
               
               
                 S10 
                 Aspheric 
                 −14.4064 
                 0.2238 
                   
                   
                   
                 89.5414 
               
               
                 S11 
                 Aspheric 
                 2.8779 
                 0.5565 
                 1.55 
                 56.1 
                 4.13 
                 −1.4337 
               
               
                 S12 
                 Aspheric 
                 −9.7299 
                 0.2869 
                   
                   
                   
                 −62.0929 
               
               
                 S13 
                 Aspheric 
                 1.1675 
                 0.4000 
                 1.64 
                 56.1 
                 −7.08 
                 −5.5851 
               
               
                 S14 
                 Aspheric 
                 0.8048 
                 0.4490 
                   
                   
                   
                 −2.1696 
               
               
                 S15 
                 Spherical 
                 Infinite 
                 0.1106 
                 1.62 
                 64.2 
               
               
                 S16 
                 Spherical 
                 Infinite 
                 0.3703 
               
               
                 S17 
                 Spherical 
                 Infinite 
               
               
                   
               
            
           
         
       
     
     
       
         
           
               
               
               
               
               
               
             
               
                 TABLE 4 
               
               
                   
               
             
            
               
                 Surface 
                   
                   
                   
                   
                   
               
               
                 number 
                 A4 
                 A6 
                 A8 
                 A10 
                 A12 
               
               
                   
               
               
                 S1 
                  5.7456E−01 
                 −1.2191E−01 
                 1.7389E−02 
                 −5.3234E−03 
                 2.4799E−03 
               
               
                 S2 
                  3.4154E−01 
                  1.6972E−04 
                 3.6608E−03 
                 −4.7255E−04 
                 4.3125E−05 
               
               
                 S3 
                 −3.9536E−02 
                 −5.9654E−03 
                 −1.0830E−03  
                 −1.8133E−04 
                 −5.3860E−05  
               
               
                 S4 
                 −3.3172E−02 
                 −2.0378E−02 
                 3.6046E−03 
                 −1.8418E−03 
                 6.9241E−04 
               
               
                 S5 
                 −3.1811E−02 
                 −3.4411E−03 
                 1.3981E−02 
                 −8.8906E−04 
                 8.4288E−04 
               
               
                 S6 
                 −2.4285E−02 
                  6.2839E−03 
                 1.9696E−02 
                 −3.8728E−04 
                 4.7266E−04 
               
               
                 S7 
                 −3.8824E−02 
                  6.4637E−03 
                 7.7709E−03 
                 −2.1135E−03 
                 2.7299E−04 
               
               
                 S8 
                 −7.7131E−03 
                 −2.0225E−02 
                 −5.9482E−03  
                 −5.5324E−03 
                 −7.9399E−04  
               
               
                 S9 
                 −1.0033E−02 
                 −1.3086E−02 
                 8.4086E−03 
                 −1.7949E−03 
                 5.1467E−04 
               
               
                 S10 
                 −3.5708E−01 
                  3.4716E−02 
                 1.4106E−02 
                  6.0758E−03 
                 7.5615E−03 
               
               
                 S11 
                 −5.7024E−01 
                 −6.2517E−02 
                 3.0849E−02 
                  2.0125E−03 
                 6.8722E−03 
               
               
                 S12 
                 −1.5257E−01 
                 −3.2803E−02 
                 4.1440E−02 
                  3.4354E−03 
                 −2.1127E−03  
               
               
                 S13 
                 −1.5113E+00 
                  3.1329E−01 
                 1.9148E−02 
                 −1.1769E−02 
                 −6.2545E−03  
               
               
                 S14 
                 −1.9218E+00 
                  4.0925E−01 
                 −1.1750E−01  
                  5.5666E−02 
                 −1.7290E−02  
               
               
                   
               
            
           
           
               
               
               
               
               
               
            
               
                   
                 Surface 
                   
                   
                   
                   
               
               
                   
                 number 
                 A14 
                 A16 
                 A18 
                 A20 
               
               
                   
                   
               
               
                   
                 S1 
                 −6.7231E−04 
                  1.8659E−04 
                 −9.0643E−05 
                  1.2607E−05 
               
               
                   
                 S2 
                  5.9618E−05 
                  2.0118E−06 
                  2.2773E−05 
                 −4.0860E−06 
               
               
                   
                 S3 
                 −1.9107E−05 
                 −1.2897E−05 
                 −3.6115E−06 
                 −3.7055E−06 
               
               
                   
                 S4 
                 −3.1449E−04 
                  1.0862E−04 
                 −4.4294E−05 
                  8.5810E−06 
               
               
                   
                 S5 
                 −5.5380E−04 
                  1.4669E−04 
                 −7.3990E−07 
                  4.0360E−05 
               
               
                   
                 S6 
                 −5.4877E−04 
                 −4.3661E−04 
                  1.2507E−04 
                 −4.5540E−05 
               
               
                   
                 S7 
                 −6.1478E−04 
                 −3.3902E−04 
                  2.0410E−04 
                 −9.9626E−05 
               
               
                   
                 S8 
                 −1.5421E−03 
                 −2.8833E−05 
                 −1.7942E−04 
                 −6.2314E−06 
               
               
                   
                 S9 
                 −1.4055E−03 
                 −4.0883E−05 
                 −1.5904E−04 
                  2.7485E−05 
               
               
                   
                 S10 
                  2.3467E−03 
                  1.0998E−03 
                  4.0892E−04 
                  1.2003E−04 
               
               
                   
                 S11 
                  1.5020E−03 
                 −1.3740E−03 
                 −4.6117E−04 
                  1.1108E−04 
               
               
                   
                 S12 
                  1.5176E−03 
                 −3.5422E−03 
                  1.4678E−03 
                  2.4375E−04 
               
               
                   
                 S13 
                 −1.5645E−03 
                  1.2598E−03 
                 −2.8705E−05 
                 −5.1463E−05 
               
               
                   
                 S14 
                  4.2182E−03 
                 −1.9620E−03 
                  1.0063E−04 
                 −1.7915E−04 
               
               
                   
                   
               
            
           
         
       
     
       FIG. 4A  illustrates a longitudinal aberration curve of the optical imaging system according to example 2, representing deviations of focal points converged by light of different wavelengths after passing through the system.  FIG. 4B  illustrates an astigmatic curve of the optical imaging system according to example 2, representing a curvature of a tangential plane and a curvature of a sagittal plane.  FIG. 4C  illustrates a lateral color curve of the optical imaging system according to example 2, representing deviations of different image heights on an imaging plane after light passes through the system. It can be seen from  FIG. 4A  to  FIG. 4C  that the optical imaging system provided in example 2 may achieve good image quality. 
     EXAMPLE 3 
     An optical imaging system according to example 3 of the present disclosure is described below with reference to  FIG. 5  to  FIG. 6C .  FIG. 5  shows a schematic structural view of the optical imaging system according to example 3 of the present disclosure. 
     As shown in  FIG. 5 , the optical imaging system includes a first lens E 1 , a stop STO, a second lens E 2 , a third lens E 3 , a fourth lens E 4 , a fifth lens E 5 , a sixth lens E 6 , a seventh lens E 7  and an optical filter E 8 , which are sequentially arranged from an object side to an image side along an optical axis. 
     The first lens E 1  has negative refractive power, an object-side surface S 1  thereof is a concave surface, and an image-side surface S 2  thereof is a concave surface. The second lens E 2  has positive refractive power, an object-side surface S 3  thereof is a convex surface, and an image-side surface S 4  thereof is a convex surface. The third lens E 3  has negative refractive power, an object-side surface S 5  thereof is a concave surface, and an image-side surface S 6  thereof is a convex surface. The fourth lens E 4  has negative refractive power, an object-side surface S 7  thereof is a convex surface, and an image-side surface S 8  thereof is a concave surface. The fifth lens E 5  has positive refractive power, an object-side surface S 9  thereof is a convex surface, and an image-side surface S 10  thereof is a concave surface. The sixth lens E 6  has positive refractive power, an object-side surface S 11  thereof is a convex surface, and an image-side surface S 12  thereof is a convex surface. The seventh lens E 7  has negative refractive power, an object-side surface S 13  thereof is a convex surface, and an image-side surface S 14  thereof is a concave surface. The optical filter E 8  has an object-side surface S 15  and an image-side surface S 16 . The optical imaging system has an imaging plane S 17 , and light from an object sequentially passes through the respective surfaces S 1  to S 16  and is finally imaged on the imaging plane S 17 . 
     In example 3, a total effective focal length f of the optical imaging system is 1.96 mm, an aperture number Fno of the optical imaging system is 1.69, an on-axis distance TTL from the object-side surface S 1  of the first lens E 1  to the imaging plane S 17  is 6.42 mm, half of a diagonal length ImgH of an effective pixel area on the imaging plane S 17  is 3.05 mm, and half of a maximal field-of-view Semi-FOV is 79.0°. 
     Table 5 is a table illustrating basic parameters of the optical imaging system of example 3, wherein the units for the radius of curvature, the thickness/distance and the focal length are millimeter (mm). Table 6 shows high-order coefficients applicable to each aspheric surface in example 3, wherein the surface shape of each aspheric surface may be defined by the formula (1) given in the above example 1. 
     
       
         
           
               
               
               
             
               
                   
                 TABLE 5 
               
             
            
               
                   
                   
               
               
                   
                 Material 
                   
               
            
           
           
               
               
               
               
               
               
               
               
            
               
                 Surface 
                 Surface 
                 Radius of 
                 Thickness/ 
                 Refractive 
                 Abbe 
                 Focal 
                 Conic 
               
               
                 number 
                 type 
                 curvature 
                 Distance 
                 index 
                 number 
                 length 
                 coefficient 
               
               
                   
               
            
           
           
               
               
               
               
               
               
               
               
            
               
                 OBJ 
                 Spherical 
                 Infinite 
                 400.0000 
                   
                   
                   
                   
               
               
                 S1 
                 Aspheric 
                 −4.3964 
                 0.4631 
                 1.55 
                 56.1 
                 −3.98 
                 −48.8831 
               
               
                 S2 
                 Aspheric 
                 4.4466 
                 1.0129 
                   
                   
                   
                 −25.8389 
               
               
                 STO 
                 Spherical 
                 Infinite 
                 −0.0363 
               
               
                 S3 
                 Aspheric 
                 4.6075 
                 1.0635 
                 1.55 
                 56.1 
                 1.89 
                 26.1063 
               
               
                 S4 
                 Aspheric 
                 −1.2227 
                 0.0500 
                   
                   
                   
                 −1.4799 
               
               
                 S5 
                 Aspheric 
                 −10.1660 
                 0.2502 
                 1.68 
                 19.2 
                 −122.33 
                 83.2690 
               
               
                 S6 
                 Aspheric 
                 −11.7023 
                 0.0350 
                   
                   
                   
                 87.6300 
               
               
                 S7 
                 Aspheric 
                 7.2290 
                 0.2300 
                 1.67 
                 20.4 
                 −3.44 
                 26.2456 
               
               
                 S8 
                 Aspheric 
                 1.7203 
                 0.1168 
                   
                   
                   
                 −18.5421 
               
               
                 S9 
                 Aspheric 
                 5.6625 
                 0.8846 
                 1.55 
                 56.1 
                 11.30 
                 11.7006 
               
               
                 S10 
                 Aspheric 
                 65.3421 
                 0.2227 
                   
                   
                   
                 −90.0000 
               
               
                 S11 
                 Aspheric 
                 2.4056 
                 0.5565 
                 1.55 
                 56.1 
                 3.54 
                 −4.2697 
               
               
                 S12 
                 Aspheric 
                 −8.9801 
                 0.3339 
                   
                   
                   
                 −40.1906 
               
               
                 S13 
                 Aspheric 
                 1.1947 
                 0.4000 
                 1.64 
                 56.1 
                 −5.51 
                 −7.9052 
               
               
                 S14 
                 Aspheric 
                 0.7767 
                 0.4003 
                   
                   
                   
                 −3.3030 
               
               
                 S15 
                 Spherical 
                 Infinite 
                 0.1100 
                 1.62 
                 64.2 
               
               
                 S16 
                 Spherical 
                 Infinite 
                 0.3222 
               
               
                 S17 
                 Spherical 
                 Infinite 
               
               
                   
               
            
           
         
       
     
     
       
         
           
               
               
               
               
               
               
             
               
                 TABLE 6 
               
               
                   
               
             
            
               
                 Surface 
                   
                   
                   
                   
                   
               
               
                 number 
                 A4 
                 A6 
                 A8 
                 A10 
                 A12 
               
               
                   
               
               
                 S1 
                  4.9559E−01 
                 −9.4409E−02 
                 1.4034E−02 
                 −4.0000E−03 
                 1.5870E−03 
               
               
                 S2 
                  2.9320E−01 
                 −1.4939E−03 
                 3.1698E−03 
                  3.4443E−05 
                 4.2948E−05 
               
               
                 S3 
                 −3.8422E−02 
                 −5.0907E−03 
                 −8.1034E−04  
                 −1.5765E−04 
                 −3.1008E−05  
               
               
                 S4 
                 −1.4793E−02 
                 −1.1056E−02 
                 1.7892E−03 
                 −8.0196E−04 
                 2.9345E−04 
               
               
                 S5 
                 −9.5978E−03 
                 −2.4235E−03 
                 7.4883E−03 
                 −7.4914E−04 
                 2.7485E−04 
               
               
                 S6 
                 −3.1479E−03 
                 −4.0740E−03 
                 9.4367E−03 
                 −6.8135E−05 
                 1.0207E−04 
               
               
                 S7 
                 −1.1924E−01 
                  9.0272E−03 
                 3.6452E−03 
                  2.0660E−04 
                 −3.9758E−04  
               
               
                 S8 
                  1.4248E−02 
                 −9.8462E−03 
                 1.7981E−03 
                 −1.7093E−03 
                 1.4705E−04 
               
               
                 S9 
                 −1.6836E−02 
                 −3.9648E−03 
                 1.4472E−03 
                  6.9227E−04 
                 −7.5512E−05  
               
               
                 S10 
                 −4.2833E−01 
                  5.1636E−02 
                 7.7022E−03 
                  4.8244E−03 
                 3.6766E−03 
               
               
                 S11 
                 −5.0598E−01 
                 −6.2485E−02 
                 8.4293E−03 
                 −9.7002E−04 
                 4.1917E−03 
               
               
                 S12 
                 −1.1098E−01 
                 −4.0722E−02 
                 1.4776E−02 
                  2.5360E−04 
                 −3.4801E−04  
               
               
                 S13 
                 −1.4397E+00 
                  3.0786E−01 
                 2.0732E−04 
                 −5.2548E−03 
                 −6.2031E−03  
               
               
                 S14 
                 −1.3172E+00 
                  2.3704E−01 
                 −8.0231E−02  
                  3.2362E−02 
                 −7.7553E−03  
               
               
                   
               
            
           
           
               
               
               
               
               
               
            
               
                   
                 Surface 
                   
                   
                   
                   
               
               
                   
                 number 
                 A14 
                 A16 
                 A18 
                 A20 
               
               
                   
                   
               
               
                   
                 S1 
                 −3.7246E−04 
                 9.2426E−05 
                 −3.1859E−05 
                 6.5656E−06 
               
               
                   
                 S2 
                  9.5461E−05 
                 −5.6197E−06  
                  2.8364E−05 
                 −1.6985E−06  
               
               
                   
                 S3 
                 −1.3026E−05 
                 −9.6888E−06  
                 −2.1428E−06 
                 −3.1395E−06  
               
               
                   
                 S4 
                 −1.3102E−04 
                 4.3997E−05 
                 −9.2394E−06 
                 6.4676E−07 
               
               
                   
                 S5 
                 −3.2233E−04 
                 1.2275E−04 
                 −1.0507E−05 
                 2.5695E−06 
               
               
                   
                 S6 
                 −3.2904E−04 
                 4.3731E−05 
                  1.5510E−05 
                 −3.4389E−06  
               
               
                   
                 S7 
                 −1.4937E−04 
                 4.3867E−05 
                  2.5233E−05 
                 −9.8676E−06  
               
               
                   
                 S8 
                 −1.8161E−04 
                 5.5324E−05 
                 −3.4733E−05 
                 7.6043E−06 
               
               
                   
                 S9 
                 −4.0569E−05 
                 −1.1912E−05  
                 −1.9681E−06 
                 2.1420E−06 
               
               
                   
                 S10 
                  1.0549E−03 
                 3.4375E−04 
                  7.7378E−05 
                 6.6220E−06 
               
               
                   
                 S11 
                  2.3446E−03 
                 −2.4846E−04  
                 −3.9279E−04 
                 −3.6509E−05  
               
               
                   
                 S12 
                  1.4238E−03 
                 −3.6551E−03  
                  4.5194E−04 
                 2.1249E−04 
               
               
                   
                 S13 
                 −1.0101E−03 
                 6.9110E−06 
                 −3.3527E−04 
                 3.7215E−04 
               
               
                   
                 S14 
                  3.4215E−03 
                 −1.3877E−03  
                  3.4036E−04 
                 −4.8577E−05  
               
               
                   
                   
               
            
           
         
       
     
       FIG. 6A  illustrates a longitudinal aberration curve of the optical imaging system according to example 3, representing deviations of focal points converged by light of different wavelengths after passing through the system.  FIG. 6B  illustrates an astigmatic curve of the optical imaging system according to example 3, representing a curvature of a tangential plane and a curvature of a sagittal plane.  FIG. 6C  illustrates a lateral color curve of the optical imaging system according to example 3, representing deviations of different image heights on an imaging plane after light passes through the system. It can be seen from  FIG. 6A  to  FIG. 6C  that the optical imaging system provided in example 3 may achieve good image quality. 
     EXAMPLE 4 
     An optical imaging system according to example 4 of the present disclosure is described below with reference to  FIG. 7  to  FIG. 8C .  FIG. 7  shows a schematic structural view of the optical imaging system according to example 4 of the present disclosure. 
     As shown in  FIG. 7 , the optical imaging system includes a first lens E 1 , a stop STO, a second lens E 2 , a third lens E 3 , a fourth lens E 4 , a fifth lens E 5 , a sixth lens E 6 , a seventh lens E 7  and an optical filter E 8 , which are sequentially arranged from an object side to an image side along an optical axis. 
     The first lens E 1  has negative refractive power, an object-side surface S 1  thereof is a concave surface, and an image-side surface S 2  thereof is a concave surface. The second lens E 2  has positive refractive power, an object-side surface S 3  thereof is a convex surface, and an image-side surface S 4  thereof is a convex surface. The third lens E 3  has negative refractive power, an object-side surface S 5  thereof is a concave surface, and an image-side surface S 6  thereof is a convex surface. The fourth lens E 4  has negative refractive power, an object-side surface S 7  thereof is a convex surface, and an image-side surface S 8  thereof is a concave surface. The fifth lens E 5  has negative refractive power, an object-side surface S 9  thereof is a convex surface, and an image-side surface S 10  thereof is a concave surface. The sixth lens E 6  has positive refractive power, an object-side surface S 11  thereof is a convex surface, and an image-side surface S 12  thereof is a convex surface. The seventh lens E 7  has negative refractive power, an object-side surface S 13  thereof is a convex surface, and an image-side surface S 14  thereof is a concave surface. The optical filter E 8  has an object-side surface S 15  and an image-side surface S 16 . The optical imaging system has an imaging plane S 17 , and light from an object sequentially passes through the respective surfaces S 1  to S 16  and is finally imaged on the imaging plane S 17 . 
     In example 4, a total effective focal length f of the optical imaging system is 1.95 mm, an aperture number Fno of the optical imaging system is 1.70, an on-axis distance TTL from the object-side surface S 1  of the first lens E 1  to the imaging plane S 17  is 6.49 mm, half of a diagonal length ImgH of an effective pixel area on the imaging plane S 17  is 3.05 mm, and half of a maximal field-of-view Semi-FOV is 77.6°. 
     Table 7 is a table illustrating basic parameters of the optical imaging system of example 4, wherein the units for the radius of curvature, the thickness/distance and the focal length are millimeter (mm). Table 8 shows high-order coefficients applicable to each aspheric surface in example 4, wherein the surface shape of each aspheric surface may be defined by the formula (1) given in the above example 1. 
     
       
         
           
               
               
               
             
               
                   
                 TABLE 7 
               
             
            
               
                   
                   
               
               
                   
                 Material 
                   
               
            
           
           
               
               
               
               
               
               
               
               
            
               
                 Surface 
                 Surface 
                 Radius of 
                 Thickness/ 
                 Refractive 
                 Abbe 
                 Focal 
                 Conic 
               
               
                 number 
                 type 
                 curvature 
                 Distance 
                 index 
                 number 
                 length 
                 coefficient 
               
               
                   
               
            
           
           
               
               
               
               
               
               
               
               
            
               
                 OBJ 
                 Spherical 
                 Infinite 
                 400.0000 
                   
                   
                   
                   
               
               
                 S1 
                 Aspheric 
                 −4.3964 
                 0.4631 
                 1.55 
                 56.1 
                 −3.98 
                 −48.8831 
               
               
                 S2 
                 Aspheric 
                 4.4466 
                 1.0129 
                   
                   
                   
                 −24.6940 
               
               
                 STO 
                 Spherical 
                 Infinite 
                 −0.0386 
               
               
                 S3 
                 Aspheric 
                 4.6075 
                 1.0945 
                 1.55 
                 56.1 
                 1.90 
                 26.1063 
               
               
                 S4 
                 Aspheric 
                 −1.2256 
                 0.0500 
                   
                   
                   
                 −1.4943 
               
               
                 S5 
                 Aspheric 
                 −10.1942 
                 0.2500 
                 1.68 
                 19.2 
                 −200.00 
                 82.3163 
               
               
                 S6 
                 Aspheric 
                 −11.1326 
                 0.0350 
                   
                   
                   
                 86.8770 
               
               
                 S7 
                 Aspheric 
                 7.9902 
                 0.2300 
                 1.67 
                 20.4 
                 −3.41 
                 26.4324 
               
               
                 S8 
                 Aspheric 
                 1.7519 
                 0.1168 
                   
                   
                   
                 −17.4437 
               
               
                 S9 
                 Aspheric 
                 5.8041 
                 0.8846 
                 1.55 
                 56.1 
                 −108.11 
                 11.5983 
               
               
                 S10 
                 Aspheric 
                 5.0000 
                 0.2227 
                   
                   
                   
                 −89.3859 
               
               
                 S11 
                 Aspheric 
                 1.6656 
                 0.5565 
                 1.55 
                 56.1 
                 2.61 
                 −5.4591 
               
               
                 S12 
                 Aspheric 
                 −8.6457 
                 0.3848 
                   
                   
                   
                 −19.3755 
               
               
                 S13 
                 Aspheric 
                 1.2078 
                 0.4000 
                 1.64 
                 56.1 
                 −5.45 
                 −8.2273 
               
               
                 S14 
                 Aspheric 
                 0.7822 
                 0.3988 
                   
                   
                   
                 −3.4089 
               
               
                 S15 
                 Spherical 
                 Infinite 
                 0.1100 
                 1.62 
                 64.2 
               
               
                 S16 
                 Spherical 
                 Infinite 
                 0.3207 
               
               
                 S17 
                 Spherical 
                 Infinite 
               
               
                   
               
            
           
         
       
     
     
       
         
           
               
               
               
               
               
               
             
               
                 TABLE 8 
               
               
                   
               
             
            
               
                 Surface 
                   
                   
                   
                   
                   
               
               
                 number 
                 A4 
                 A6 
                 A8 
                 A10 
                 A12 
               
               
                   
               
               
                 S1 
                  4.9170E−01 
                 −9.4622E−02 
                 1.3675E−02 
                 −3.6720E−03 
                 1.6128E−03 
               
               
                 S2 
                  2.9135E−01 
                 −2.4624E−03 
                 2.8951E−03 
                 −8.3071E−05 
                 7.3135E−05 
               
               
                 S3 
                 −3.6524E−02 
                 −4.9515E−03 
                 −8.3859E−04  
                 −1.5765E−04 
                 −4.6550E−05  
               
               
                 S4 
                 −1.4447E−02 
                 −1.1249E−02 
                 2.2266E−03 
                 −9.9907E−04 
                 3.5901E−04 
               
               
                 S5 
                 −2.2905E−02 
                 −5.7246E−03 
                 8.5842E−03 
                 −1.2203E−03 
                 3.7272E−04 
               
               
                 S6 
                 −7.5618E−03 
                 −5.3002E−03 
                 9.5212E−03 
                 −7.0716E−05 
                 5.6805E−05 
               
               
                 S7 
                 −1.1857E−01 
                  9.7179E−03 
                 3.3313E−03 
                  2.3635E−04 
                 −3.2078E−04  
               
               
                 S8 
                  1.1699E−02 
                 −8.9390E−03 
                 1.9546E−03 
                 −1.4924E−03 
                 2.9177E−04 
               
               
                 S9 
                 −1.4979E−02 
                 −3.6692E−03 
                 1.2766E−03 
                  7.7352E−04 
                 −1.1699E−04  
               
               
                 S10 
                 −5.0351E−01 
                  6.2196E−02 
                 −1.9921E−03  
                  4.4512E−03 
                 1.5626E−03 
               
               
                 S11 
                 −4.9414E−01 
                 −4.9746E−02 
                 4.2279E−03 
                  9.9522E−04 
                 2.8729E−03 
               
               
                 S12 
                 −4.9909E−02 
                 −3.0220E−02 
                 1.5141E−02 
                  1.2042E−03 
                 −2.4675E−04  
               
               
                 S13 
                 −1.4346E+00 
                  3.0819E−01 
                 3.6116E−03 
                 −2.3629E−03 
                 −7.5139E−03  
               
               
                 S14 
                 −1.3252E+00 
                  2.3658E−01 
                 −8.7312E−02  
                  3.2027E−02 
                 −7.9054E−03  
               
               
                   
               
            
           
           
               
               
               
               
               
               
            
               
                   
                 Surface 
                   
                   
                   
                   
               
               
                   
                 number 
                 A14 
                 A16 
                 A18 
                 A20 
               
               
                   
                   
               
               
                   
                 S1 
                 −3.6274E−04 
                 8.0280E−05 
                 −3.3956E−05 
                 6.1591E−06 
               
               
                   
                 S2 
                  8.4243E−05 
                 6.4205E−06 
                  2.2746E−05 
                 2.5386E−06 
               
               
                   
                 S3 
                 −1.3026E−05 
                 −9.6888E−06  
                 −2.1428E−06 
                 −3.1395E−06  
               
               
                   
                 S4 
                 −1.4005E−04 
                 4.3313E−05 
                 −9.1319E−06 
                 7.5207E−07 
               
               
                   
                 S5 
                 −3.5561E−04 
                 1.2257E−04 
                 −8.7592E−06 
                 4.3086E−06 
               
               
                   
                 S6 
                 −2.8524E−04 
                 2.7169E−05 
                  1.5409E−05 
                 −1.9026E−06  
               
               
                   
                 S7 
                 −1.7053E−04 
                 4.8843E−05 
                  1.8046E−05 
                 −7.0029E−06  
               
               
                   
                 S8 
                 −2.1042E−04 
                 7.8208E−05 
                 −3.4760E−05 
                 6.2030E−06 
               
               
                   
                 S9 
                 −1.3047E−05 
                 −1.0638E−05  
                 −1.1573E−06 
                 1.4840E−06 
               
               
                   
                 S10 
                  9.1070E−04 
                 7.3151E−05 
                  1.1786E−04 
                 −1.3480E−05  
               
               
                   
                 S11 
                  3.0528E−03 
                 −3.7499E−04  
                 −2.5275E−04 
                 −3.5319E−05  
               
               
                   
                 S12 
                  1.6489E−03 
                 −3.3610E−03  
                  6.0160E−04 
                 3.1834E−04 
               
               
                   
                 S13 
                 −1.6751E−03 
                 7.0025E−04 
                 −2.7073E−04 
                 3.6373E−04 
               
               
                   
                 S14 
                  3.9914E−03 
                 −1.0494E−03  
                  2.9261E−04 
                 −1.0087E−04  
               
               
                   
                   
               
            
           
         
       
     
       FIG. 8A  illustrates a longitudinal aberration curve of the optical imaging system according to example 4, representing deviations of focal points converged by light of different wavelengths after passing through the system.  FIG. 8B  illustrates an astigmatic curve of the optical imaging system according to example 4, representing a curvature of a tangential plane and a curvature of a sagittal plane.  FIG. 8C  illustrates a lateral color curve of the optical imaging system according to example 4, representing deviations of different image heights on an imaging plane after light passes through the system. It can be seen from  FIG. 8A  to  FIG. 8C  that the optical imaging system provided in example 4 may achieve good image quality. 
     EXAMPLE 5 
     An optical imaging system according to example 5 of the present disclosure is described below with reference to  FIG. 9  to  FIG. 10C .  FIG. 9  shows a schematic structural view of the optical imaging system according to example 5 of the present disclosure. 
     As shown in  FIG. 9 , the optical imaging system includes a first lens E 1 , a stop STO, a second lens E 2 , a third lens E 3 , a fourth lens E 4 , a fifth lens E 5 , a sixth lens E 6 , a seventh lens E 7  and an optical filter E 8 , which are sequentially arranged from an object side to an image side along an optical axis. 
     The first lens E 1  has negative refractive power, an object-side surface S 1  thereof is a concave surface, and an image-side surface S 2  thereof is a concave surface. The second lens E 2  has positive refractive power, an object-side surface S 3  thereof is a convex surface, and an image-side surface S 4  thereof is a convex surface. The third lens E 3  has positive refractive power, an object-side surface S 5  thereof is a concave surface, and an image-side surface S 6  thereof is a convex surface. The fourth lens E 4  has negative refractive power, an object-side surface S 7  thereof is a convex surface, and an image-side surface S 8  thereof is a concave surface. The fifth lens E 5  has positive refractive power, an object-side surface S 9  thereof is a convex surface, and an image-side surface S 10  thereof is a convex surface. The sixth lens E 6  has positive refractive power, an object-side surface S 11  thereof is a convex surface, and an image-side surface S 12  thereof is a convex surface. The seventh lens E 7  has negative refractive power, an object-side surface S 13  thereof is a convex surface, and an image-side surface S 14  thereof is a concave surface. The optical filter E 8  has an object-side surface S 15  and an image-side surface S 16 . The optical imaging system has an imaging plane S 17 , and light from an object sequentially passes through the respective surfaces S 1  to S 16  and is finally imaged on the imaging plane S 17 . 
     In example 5, a total effective focal length f of the optical imaging system is 1.97 mm, an aperture number Fno of the optical imaging system is 1.70, an on-axis distance TTL from the object-side surface S 1  of the first lens E 1  to the imaging plane S 17  is 6.34 mm, half of a diagonal length ImgH of an effective pixel area on the imaging plane S 17  is 3.05 mm, and half of a maximal field-of-view Semi-FOV is 80.5°. 
     Table 9 is a table illustrating basic parameters of the optical imaging system of example 5, wherein the units for the radius of curvature, the thickness/distance and the focal length are millimeter (mm). Table 10 shows high-order coefficients applicable to each aspheric surface in example 5, wherein the surface shape of each aspheric surface may be defined by the formula (1) given in the above example 1. 
     
       
         
           
               
               
               
             
               
                   
                 TABLE 9 
               
             
            
               
                   
                   
               
               
                   
                 Material 
                   
               
            
           
           
               
               
               
               
               
               
               
               
            
               
                 Surface 
                 Surface 
                 Radius of 
                 Thickness/ 
                 Refractive 
                 Abbe 
                 Focal 
                 Conic 
               
               
                 number 
                 type 
                 curvature 
                 Distance 
                 index 
                 number 
                 length 
                 coefficient 
               
               
                   
               
            
           
           
               
               
               
               
               
               
               
               
            
               
                 OBJ 
                 Spherical 
                 Infinite 
                 400.0000 
                   
                   
                   
                   
               
               
                 S1 
                 Aspheric 
                 −4.4396 
                 0.4607 
                 1.55 
                 56.1 
                 −3.96 
                 −48.8831 
               
               
                 S2 
                 Aspheric 
                 4.3598 
                 1.0079 
                   
                   
                   
                 −16.2570 
               
               
                 STO 
                 Spherical 
                 Infinite 
                 −0.0309 
               
               
                 S3 
                 Aspheric 
                 4.5846 
                 1.0166 
                 1.55 
                 56.1 
                 1.91 
                 26.1063 
               
               
                 S4 
                 Aspheric 
                 −1.2451 
                 0.0500 
                   
                   
                   
                 −1.4040 
               
               
                 S5 
                 Aspheric 
                 −11.5193 
                 0.2546 
                 1.68 
                 19.2 
                 180.00 
                 89.8767 
               
               
                 S6 
                 Aspheric 
                 −10.6192 
                 0.0350 
                   
                   
                   
                 81.6186 
               
               
                 S7 
                 Aspheric 
                 10.2984 
                 0.2300 
                 1.67 
                 20.4 
                 −3.39 
                 57.0269 
               
               
                 S8 
                 Aspheric 
                 1.8390 
                 0.1162 
                   
                   
                   
                 −17.4526 
               
               
                 S9 
                 Aspheric 
                 6.1550 
                 0.8802 
                 1.55 
                 56.1 
                 7.99 
                 10.2660 
               
               
                 S10 
                 Aspheric 
                 −14.2121 
                 0.2216 
                   
                   
                   
                 89.6265 
               
               
                 S11 
                 Aspheric 
                 2.8685 
                 0.5537 
                 1.55 
                 56.1 
                 4.12 
                 −3.8181 
               
               
                 S12 
                 Aspheric 
                 −9.6723 
                 0.2537 
                   
                   
                   
                 9.6846 
               
               
                 S13 
                 Aspheric 
                 1.1118 
                 0.4000 
                 1.64 
                 56.1 
                 −5.36 
                 −6.9172 
               
               
                 S14 
                 Aspheric 
                 0.7224 
                 0.4309 
                   
                   
                   
                 −3.3397 
               
               
                 S15 
                 Spherical 
                 Infinite 
                 0.1100 
                 1.62 
                 64.2 
               
               
                 S16 
                 Spherical 
                 Infinite 
                 0.3528 
               
               
                 S17 
                 Spherical 
                 Infinite 
               
               
                   
               
            
           
         
       
     
     
       
         
           
               
               
               
               
               
               
             
               
                 TABLE 10 
               
               
                   
               
             
            
               
                 Surface 
                   
                   
                   
                   
                   
               
               
                 number 
                 A4 
                 A6 
                 A8 
                 A10 
                 A12 
               
               
                   
               
               
                 S1 
                  5.6067E−01 
                 −1.1635E−01 
                 1.7168E−02 
                 −4.6445E−03 
                 2.1767E−03 
               
               
                 S2 
                  3.0711E−01 
                 −9.5244E−04 
                 3.0149E−03 
                 −1.2173E−04 
                 4.7125E−05 
               
               
                 S3 
                  4.2045E−02 
                 −5.8550E−03 
                 −1.0215E−03  
                 −1.6166E−04 
                 −4.9678E−05  
               
               
                 S4 
                 −3.6197E−02 
                 −1.5591E−02 
                 2.1553E−03 
                 −1.3992E−03 
                 5.0386E−04 
               
               
                 S5 
                 −3.0020E−02 
                 −6.4842E−04 
                 1.1598E−02 
                 −1.9814E−03 
                 4.2709E−04 
               
               
                 S6 
                  1.5999E−02 
                  2.5960E−03 
                 1.9985E−02 
                 −2.2259E−03 
                 4.7339E−04 
               
               
                 S7 
                 −1.1688E−01 
                  1.6822E−02 
                 4.2959E−03 
                 −4.1409E−03 
                 −6.6816E−04  
               
               
                 S8 
                  7.3989E−03 
                 −1.3988E−02 
                 −5.3138E−03  
                 −4.2454E−03 
                 −6.2950E−04  
               
               
                 S9 
                  5.4458E−04 
                 −8.5128E−03 
                 6.9130E−03 
                 −1.8274E−03 
                 1.3796E−04 
               
               
                 S10 
                 −3.3210E−01 
                  3.8816E−02 
                 1.0229E−02 
                  3.5535E−03 
                 3.9503E−03 
               
               
                 S11 
                 −5.2412E−01 
                 −6.1840E−02 
                 2.0916E−02 
                 −5.1761E−03 
                 2.3687E−03 
               
               
                 S12 
                 −1.6150E−01 
                 −2.4327E−02 
                 2.7840E−02 
                 −5.5781E−03 
                 −2.1012E−03  
               
               
                 S13 
                 −1.4956E+00 
                  3.3243E−01 
                 −3.1787E−03  
                 −3.3867E−03 
                 −1.0815E−02  
               
               
                 S14 
                 −1.4013E+00 
                  2.5688E−01 
                 −7.9976E−02  
                  4.1430E−02 
                 −1.2566E−02  
               
               
                   
               
            
           
           
               
               
               
               
               
               
            
               
                   
                 Surface 
                   
                   
                   
                   
               
               
                   
                 number 
                 A14 
                 A16 
                 A18 
                 A20 
               
               
                   
                   
               
               
                   
                 S1 
                 −5.7817E−04 
                 1.4473E−04 
                 −5.9501E−05 
                 1.3598E−05 
               
               
                   
                 S2 
                  9.4750E−05 
                 −3.3483E−06  
                  2.6356E−05 
                 −7.0911E−06  
               
               
                   
                 S3 
                 −1.3956E−05 
                 −1.0167E−05  
                 −2.3793E−06 
                 −3.2212E−06  
               
               
                   
                 S4 
                 −2.4552E−04 
                 8.2932E−05 
                 −2.6538E−05 
                 3.1176E−06 
               
               
                   
                 S5 
                 −5.2637E−04 
                 1.9187E−04 
                 −1.0015E−05 
                 2.7983E−06 
               
               
                   
                 S6 
                 −7.3371E−04 
                 1.3881E−04 
                  5.6060E−05 
                 −1.3990E−05  
               
               
                   
                 S7 
                 −8.2320E−04 
                 1.5595E−04 
                 −1.5299E−04 
                 −8.7570E−05  
               
               
                   
                 S8 
                 −9.9692E−04 
                 3.9495E−05 
                 −1.4550E−04 
                 2.1918E−05 
               
               
                   
                 S9 
                 −6.9760E−04 
                 9.4094E−06 
                 −8.1745E−05 
                 5.8839E−07 
               
               
                   
                 S10 
                  8.5523E−04 
                 4.2081E−04 
                  1.1743E−04 
                 3.5553E−05 
               
               
                   
                 S11 
                  1.6241E−03 
                 1.7850E−04 
                 −1.3383E−04 
                 1.3292E−04 
               
               
                   
                 S12 
                  5.9534E−03 
                 −2.7926E−03  
                  7.5321E−04 
                 −7.0497E−05  
               
               
                   
                 S13 
                  5.3505E−03 
                 5.5741E−04 
                 −1.1081E−03 
                 1.9244E−04 
               
               
                   
                 S14 
                  6.2677E−03 
                 −2.5515E−03  
                  7.9495E−04 
                 −2.8551E−04  
               
               
                   
                   
               
            
           
         
       
     
       FIG. 10A  illustrates a longitudinal aberration curve of the optical imaging system according to example 5, representing deviations of focal points converged by light of different wavelengths after passing through the system.  FIG. 10B  illustrates an astigmatic curve of the optical imaging system according to example 5, representing a curvature of a tangential plane and a curvature of a sagittal plane.  FIG. 10C  illustrates a lateral color curve of the optical imaging system according to example 5, representing deviations of different image heights on an imaging plane after light passes through the system. It can be seen from  FIG. 10A  to  FIG. 10C  that the optical imaging system provided in example 5 may achieve good image quality. 
     EXAMPLE 6 
     An optical imaging system according to example 6 of the present disclosure is described below with reference to  FIG. 11  to  FIG. 12C .  FIG. 11  shows a schematic structural view of the optical imaging system according to example 6 of the present disclosure. 
     As shown in  FIG. 11 , the optical imaging system includes a first lens E 1 , a stop STO, a second lens E 2 , a third lens E 3 , a fourth lens E 4 , a fifth lens E 5 , a sixth lens E 6 , a seventh lens E 7  and an optical filter E 8 , which are sequentially arranged from an object side to an image side along an optical axis. 
     The first lens E 1  has negative refractive power, an object-side surface S 1  thereof is a concave surface, and an image-side surface S 2  thereof is a concave surface. The second lens E 2  has positive refractive power, an object-side surface S 3  thereof is a convex surface, and an image-side surface S 4  thereof is a convex surface. The third lens E 3  has negative refractive power, an object-side surface S 5  thereof is a concave surface, and an image-side surface S 6  thereof is a convex surface. The fourth lens E 4  has negative refractive power, an object-side surface S 7  thereof is a convex surface, and an image-side surface S 8  thereof is a concave surface. The fifth lens E 5  has positive refractive power, an object-side surface S 9  thereof is a convex surface, and an image-side surface S 10  thereof is a convex surface. The sixth lens E 6  has positive refractive power, an object-side surface S 11  thereof is a convex surface, and an image-side surface S 12  thereof is a concave surface. The seventh lens E 7  has negative refractive power, an object-side surface S 13  thereof is a convex surface, and an image-side surface S 14  thereof is a concave surface. The optical filter E 8  has an object-side surface S 15  and an image-side surface S 16 . The optical imaging system has an imaging plane S 17 , and light from an object sequentially passes through the respective surfaces S 1  to S 16  and is finally imaged on the imaging plane S 17 . 
     In example 6, a total effective focal length f of the optical imaging system is 1.98 mm, an aperture number Fno of the optical imaging system is 1.70, an on-axis distance TTL from the object-side surface S 1  of the first lens E 1  to the imaging plane S 17  is 6.42 mm, half of a diagonal length ImgH of an effective pixel area on the imaging plane S 17  is 3.07 mm, and half of a maximal field-of-view Semi-FOV is 78.5°. 
     Table 11 is a table illustrating basic parameters of the optical imaging system of example 6, wherein the units for the radius of curvature, the thickness/distance and the focal length are millimeter (mm). Table 12 shows high-order coefficients applicable to each aspheric surface in example 6, wherein the surface shape of each aspheric surface may be defined by the formula (1) given in the above example 1. 
     
       
         
           
               
               
               
             
               
                   
                 TABLE 11 
               
             
            
               
                   
                   
               
               
                   
                 Material 
                   
               
            
           
           
               
               
               
               
               
               
               
               
            
               
                 Surface 
                 Surface 
                 Radius of 
                 Thickness/ 
                 Refractive 
                 Abbe 
                 Focal 
                 Conic 
               
               
                 number 
                 type 
                 curvature 
                 Distance 
                 index 
                 number 
                 length 
                 coefficient 
               
               
                   
               
            
           
           
               
               
               
               
               
               
               
               
            
               
                 OBJ 
                 Spherical 
                 Infinite 
                 400.0000 
                   
                   
                   
                   
               
               
                 S1 
                 Aspheric 
                 −4.4832 
                 0.4631 
                 1.55 
                 56.1 
                 −3.98 
                 −48.8831 
               
               
                 S2 
                 Aspheric 
                 4.3612 
                 1.0129 
                   
                   
                   
                 −39.4747 
               
               
                 STO 
                 Spherical 
                 Infinite 
                 −0.0266 
               
               
                 S3 
                 Aspheric 
                 4.6075 
                 1.0634 
                 1.55 
                 56.1 
                 1.89 
                 26.1063 
               
               
                 S4 
                 Aspheric 
                 −1.2199 
                 0.0500 
                   
                   
                   
                 −1.5424 
               
               
                 S5 
                 Aspheric 
                 −10.4709 
                 0.2500 
                 1.68 
                 19.2 
                 −118.18 
                 88.9903 
               
               
                 S6 
                 Aspheric 
                 −12.1622 
                 0.0350 
                   
                   
                   
                 90.0000 
               
               
                 S7 
                 Aspheric 
                 9.8620 
                 0.2250 
                 1.67 
                 20.4 
                 −3.41 
                 48.4458 
               
               
                 S8 
                 Aspheric 
                 1.8320 
                 0.1168 
                   
                   
                   
                 −16.5809 
               
               
                 S9 
                 Aspheric 
                 5.8761 
                 0.8846 
                 1.55 
                 56.1 
                 7.76 
                 9.8780 
               
               
                 S10 
                 Aspheric 
                 −14.3993 
                 0.2227 
                   
                   
                   
                 89.3071 
               
               
                 S11 
                 Aspheric 
                 2.6854 
                 0.5565 
                 1.55 
                 56.1 
                 5.05 
                 −3.0633 
               
               
                 S12 
                 Aspheric 
                 99.0000 
                 0.3077 
                   
                   
                   
                 90.0000 
               
               
                 S13 
                 Aspheric 
                 1.0226 
                 0.4000 
                 1.64 
                 56.1 
                 −7.69 
                 −5.8720 
               
               
                 S14 
                 Aspheric 
                 0.7178 
                 0.4142 
                   
                   
                   
                 −3.1208 
               
               
                 S15 
                 Spherical 
                 Infinite 
                 0.1100 
                 1.62 
                 64.2 
               
               
                 S16 
                 Spherical 
                 Infinite 
                 0.3361 
               
               
                 S17 
                 Spherical 
                 Infinite 
               
               
                   
               
            
           
         
       
     
     
       
         
           
               
               
               
               
               
               
             
               
                 TABLE 12 
               
               
                   
               
             
            
               
                 Surface 
                   
                   
                   
                   
                   
               
               
                 number 
                 A4 
                 A6 
                 A8 
                 A10 
                 A12 
               
               
                   
               
               
                 S1 
                  5.4891E−01 
                 −1.0738E−01 
                 1.6424E−02 
                 −4.8712E−03 
                 2.0229E−03 
               
               
                 S2 
                  3.1466E−01 
                 −2.8263E−03 
                 3.5314E−03 
                 −1.8167E−04 
                 1.8540E−05 
               
               
                 S3 
                 −4.1785E−02 
                 −5.8539E−03 
                 −1.0277E−03  
                 −1.8282E−04 
                 −5.2210E−05  
               
               
                 S4 
                 −3.8254E−02 
                 −1.9001E−02 
                 2.9687E−03 
                 −1.8024E−03 
                 6.5313E−04 
               
               
                 S5 
                 −2.7290E−02 
                 −3.6993E−03 
                 1.4044E−02 
                 −1.7994E−03 
                 7.9083E−04 
               
               
                 S6 
                 −5.8998E−03 
                  1.2785E−03 
                 2.1758E−02 
                 −3.3143E−03 
                 8.4457E−04 
               
               
                 S7 
                 −1.1896E−01 
                  1.8898E−02 
                 4.8164E−03 
                 −3.7819E−03 
                 4.9831E−04 
               
               
                 S8 
                  1.1253E−02 
                 −7.8454E−03 
                 −3.0804E−03  
                 −2.9907E−03 
                 1.5999E−04 
               
               
                 S9 
                 −6.8539E−03 
                 −8.9735E−03 
                 7.5201E−03 
                 −1.1912E−03 
                 6.6737E−04 
               
               
                 S10 
                 −3.1298E−01 
                  3.3932E−02 
                 1.0588E−02 
                  2.5579E−03 
                 4.4133E−03 
               
               
                 S11 
                 −4.8121E−01 
                 −6.8147E−02 
                 1.6194E−02 
                 −6.0683E−03 
                 2.1199E−03 
               
               
                 S12 
                 −3.0742E−01 
                 −1.3759E−02 
                 1.3594E−02 
                 −1.8078E−03 
                 −4.0984E−03  
               
               
                 S13 
                 −1.5556E+00 
                  3.3264E−01 
                 −7.7589E−03  
                 −2.8075E−03 
                 −8.6348E−03  
               
               
                 S14 
                 −1.6292E+00 
                  3.3246E−01 
                 −9.4786E−02  
                  5.4738E−02 
                 −1.5896E−02  
               
               
                   
               
            
           
           
               
               
               
               
               
               
            
               
                   
                 Surface 
                   
                   
                   
                   
               
               
                   
                 number 
                 A14 
                 A16 
                 A18 
                 A20 
               
               
                   
                   
               
               
                   
                 S1 
                 −5.3189E−04 
                 1.5290E−04 
                 −5.7767E−05 
                 1.2283E−05 
               
               
                   
                 S2 
                  6.7907E−05 
                 −1.5328E−05  
                  2.5384E−05 
                 −7.0298E−06  
               
               
                   
                 S3 
                 −1.8432E−05 
                 −1.2530E−05  
                 −3.4565E−06 
                 −3.6375E−06  
               
               
                   
                 S4 
                 −3.3060E−04 
                 1.1409E−04 
                 −4.2539E−05 
                 7.2466E−06 
               
               
                   
                 S5 
                 −6.2475E−04 
                 2.3812E−04 
                 −5.5041E−06 
                 2.7222E−05 
               
               
                   
                 S6 
                 −1.0242E−03 
                 9.2747E−05 
                  5.2606E−05 
                 −5.2555E−06  
               
               
                   
                 S7 
                 −8.8747E−04 
                 2.0330E−04 
                 −1.0887E−05 
                 −5.2921E−05  
               
               
                   
                 S8 
                 −8.3239E−04 
                 1.5106E−04 
                 −1.1710E−04 
                 2.7304E−05 
               
               
                   
                 S9 
                 −6.2349E−04 
                 1.4305E−04 
                 −7.5386E−05 
                 1.9243E−05 
               
               
                   
                 S10 
                  7.9872E−04 
                 4.3808E−04 
                  1.3148E−04 
                 4.2643E−05 
               
               
                   
                 S11 
                  1.4660E−03 
                 −3.0995E−05  
                 −1.5708E−04 
                 8.7665E−05 
               
               
                   
                 S12 
                  5.7376E−03 
                 −2.8717E−03  
                  9.2347E−04 
                 −1.5257E−04  
               
               
                   
                 S13 
                  3.7659E−03 
                 1.2150E−03 
                 −1.2527E−03 
                 2.3787E−04 
               
               
                   
                 S14 
                  7.8387E−03 
                 −3.5081E−03  
                  4.8957E−04 
                 −4.8793E−04  
               
               
                   
                   
               
            
           
         
       
     
       FIG. 12A  illustrates a longitudinal aberration curve of the optical imaging system according to example 6, representing deviations of focal points converged by light of different wavelengths after passing through the system.  FIG. 12B  illustrates an astigmatic curve of the optical imaging system according to example 6, representing a curvature of a tangential plane and a curvature of a sagittal plane.  FIG. 12C  illustrates a lateral color curve of the optical imaging system according to example 6, representing deviations of different image heights on an imaging plane after light passes through the system. It can be seen from  FIG. 12A  to  FIG. 12C  that the optical imaging system provided in example 6 may achieve good image quality. 
     EXAMPLE 7 
     An optical imaging system according to example 7 of the present disclosure is described below with reference to  FIG. 13  to  FIG. 14C .  FIG. 13  shows a schematic structural view of the optical imaging system according to example 7 of the present disclosure. 
     As shown in  FIG. 13 , the optical imaging system includes a first lens E 1 , a stop STO, a second lens E 2 , a third lens E 3 , a fourth lens E 4 , a fifth lens E 5 , a sixth lens E 6 , a seventh lens E 7  and an optical filter E 8 , which are sequentially arranged from an object side to an image side along an optical axis. 
     The first lens E 1  has negative refractive power, an object-side surface S 1  thereof is a concave surface, and an image-side surface S 2  thereof is a concave surface. The second lens E 2  has positive refractive power, an object-side surface S 3  thereof is a convex surface, and an image-side surface S 4  thereof is a convex surface. The third lens E 3  has negative refractive power, an object-side surface S 5  thereof is a concave surface, and an image-side surface S 6  thereof is a convex surface. The fourth lens E 4  has negative refractive power, an object-side surface S 7  thereof is a convex surface, and an image-side surface S 8  thereof is a concave surface. The fifth lens E 5  has negative refractive power, an object-side surface S 9  thereof is a convex surface, and an image-side surface S 10  thereof is a convex surface. The sixth lens E 6  has positive refractive power, an object-side surface S 11  thereof is a convex surface, and an image-side surface S 12  thereof is a concave surface. The seventh lens E 7  has negative refractive power, an object-side surface S 13  thereof is a convex surface, and an image-side surface S 14  thereof is a concave surface. The optical filter E 8  has an object-side surface S 15  and an image-side surface S 16 . The optical imaging system has an imaging plane S 17 , and light from an object sequentially passes through the respective surfaces S 1  to S 16  and is finally imaged on the imaging plane S 17 . 
     In example 7, a total effective focal length f of the optical imaging system is 1.95 mm, an aperture number Fno of the optical imaging system is 1.70, an on-axis distance TTL from the object-side surface S 1  of the first lens E 1  to the imaging plane S 17  is 6.49 mm, half of a diagonal length ImgH of an effective pixel area on the imaging plane S 17  is 2.45 mm, and half of a maximal field-of-view Semi-FOV is 55.2°. 
     Table 13 is a table illustrating basic parameters of the optical imaging system of example 7, wherein the units for the radius of curvature, the thickness/distance and the focal length are millimeter (mm). Table 14 shows high-order coefficients applicable to each aspheric surface in example 7, wherein the surface shape of each aspheric surface may be defined by the formula (1) given in the above example 1. 
     
       
         
           
               
               
               
             
               
                   
                 TABLE 13 
               
             
            
               
                   
                   
               
               
                   
                 Material 
                   
               
            
           
           
               
               
               
               
               
               
               
               
            
               
                 Surface 
                 Surface 
                 Radius of 
                 Thickness/ 
                 Refractive 
                 Abbe 
                 Focal 
                 Conic 
               
               
                 number 
                 type 
                 curvature 
                 Distance 
                 index 
                 number 
                 length 
                 coefficient 
               
               
                   
               
            
           
           
               
               
               
               
               
               
               
               
            
               
                 OBJ 
                 Spherical 
                 Infinite 
                 400.0000 
                   
                   
                   
                   
               
               
                 S1 
                 Aspheric 
                 −4.3964 
                 0.4631 
                 1.55 
                 56.1 
                 −3.98 
                 −48.8831 
               
               
                 S2 
                 Aspheric 
                 4.4466 
                 1.0129 
                   
                   
                   
                 −24.6940 
               
               
                 STO 
                 Spherical 
                 Infinite 
                 −0.0386 
               
               
                 S3 
                 Aspheric 
                 4.6075 
                 1.0945 
                 1.55 
                 56.1 
                 1.90 
                 26.1063 
               
               
                 S4 
                 Aspheric 
                 −1.2256 
                 0.0500 
                   
                   
                   
                 −1.4943 
               
               
                 S5 
                 Aspheric 
                 −10.1942 
                 0.2500 
                 1.68 
                 19.2 
                 −200.00 
                 82.3163 
               
               
                 S6 
                 Aspheric 
                 −11.1326 
                 0.0350 
                   
                   
                   
                 86.8770 
               
               
                 S7 
                 Aspheric 
                 7.9902 
                 0.2300 
                 1.67 
                 20.4 
                 −3.41 
                 26.4324 
               
               
                 S8 
                 Aspheric 
                 1.7519 
                 0.1168 
                   
                   
                   
                 −17.4437 
               
               
                 S9 
                 Aspheric 
                 5.8041 
                 0.8846 
                 1.55 
                 56.1 
                 −108.11 
                 11.5983 
               
               
                 S10 
                 Aspheric 
                 5.0000 
                 0.2227 
                   
                   
                   
                 −89.3859 
               
               
                 S11 
                 Aspheric 
                 1.6656 
                 0.5565 
                 1.55 
                 56.1 
                 2.61 
                 −5.4591 
               
               
                 S12 
                 Aspheric 
                 −8.6457 
                 0.3848 
                   
                   
                   
                 −19.3755 
               
               
                 S13 
                 Aspheric 
                 1.2078 
                 0.4000 
                 1.64 
                 56.1 
                 −5.45 
                 −8.2273 
               
               
                 S14 
                 Aspheric 
                 0.7822 
                 0.3988 
                   
                   
                   
                 −3.4089 
               
               
                 S15 
                 Spherical 
                 Infinite 
                 0.1100 
                 1.62 
                 64.2 
               
               
                 S16 
                 Spherical 
                 Infinite 
                 0.3207 
               
               
                 S17 
                 Spherical 
                 Infinite 
               
               
                   
               
            
           
         
       
     
     
       
         
           
               
               
               
               
               
               
             
               
                 TABLE 14 
               
               
                   
               
             
            
               
                 Surface 
                   
                   
                   
                   
                   
               
               
                 number 
                 A4 
                 A6 
                 A8 
                 A10 
                 A12 
               
               
                   
               
               
                 S1 
                  5.4891E−01 
                 −1.0738E−01 
                 1.6424E−02 
                 −4.8712E−03 
                 2.0229E−03 
               
               
                 S2 
                  3.1466E−01 
                 −2.8263E−03 
                 3.5314E−03 
                 −1.8167E−04 
                 1.8540E−05 
               
               
                 S3 
                 −4.1785E−02 
                 −5.8539E−03 
                 −1.0277E−03  
                 −1.8282E−04 
                 −5.2210E−05  
               
               
                 S4 
                 −3.8254E−02 
                 −1.9001E−02 
                 2.9687E−03 
                 −1.8024E−03 
                 6.5313E−04 
               
               
                 S5 
                 −2.7290E−02 
                 −3.6993E−03 
                 1.4044E−02 
                 −1.7994E−03 
                 7.9083E−04 
               
               
                 S6 
                 −5.8998E−03 
                  1.2785E−03 
                 2.1758E−02 
                 −3.3143E−03 
                 8.4457E−04 
               
               
                 S7 
                 −1.1896E−01 
                  1.8898E−02 
                 4.8164E−03 
                 −3.7819E−03 
                 4.9831E−04 
               
               
                 S8 
                  1.1253E−02 
                 −7.8454E−03 
                 −3.0804E−03  
                 −2.9907E−03 
                 1.5999E−04 
               
               
                 S9 
                 −6.8539E−03 
                 −8.9735E−03 
                 7.5201E−03 
                 −1.1912E−03 
                 6.6737E−04 
               
               
                 S10 
                 −3.1298E−01 
                  3.3932E−02 
                 1.0588E−02 
                  2.5579E−03 
                 4.4133E−03 
               
               
                 S11 
                 −4.8121E−01 
                 −6.8147E−02 
                 1.6194E−02 
                 −6.0683E−03 
                 2.1199E−03 
               
               
                 S12 
                 −3.0742E−01 
                 −1.3759E−02 
                 1.3594E−02 
                 −1.8078E−03 
                 −4.0984E−03  
               
               
                 S13 
                 −1.5556E+00 
                  3.3264E−01 
                 −7.7589E−03  
                 −2.8075E−03 
                 −8.6348E−03  
               
               
                 S14 
                 −1.6292E+00 
                  3.3246E−01 
                 −9.4786E−02  
                  5.4738E−02 
                 −1.5896E−02  
               
               
                   
               
            
           
           
               
               
               
               
               
               
            
               
                   
                 Surface 
                   
                   
                   
                   
               
               
                   
                 number 
                 A14 
                 A16 
                 A18 
                 A20 
               
               
                   
                   
               
               
                   
                 S1 
                 −5.3189E−04 
                 1.5290E−04 
                 −5.7767E−05 
                 1.2283E−05 
               
               
                   
                 S2 
                  6.7907E−05 
                 −1.5328E−05  
                  2.5384E−05 
                 −7.0298E−06  
               
               
                   
                 S3 
                 −1.8432E−05 
                 −1.2530E−05  
                 −3.4565E−06 
                 −3.6375E−06  
               
               
                   
                 S4 
                 −3.3060E−04 
                 1.1409E−04 
                 −4.2539E−05 
                 7.2466E−06 
               
               
                   
                 S5 
                 −6.2475E−04 
                 2.3812E−04 
                 −5.5041E−06 
                 2.7222E−05 
               
               
                   
                 S6 
                 −1.0242E−03 
                 9.2747E−05 
                  5.2606E−05 
                 −5.2555E−06  
               
               
                   
                 S7 
                 −8.8747E−04 
                 2.0330E−04 
                 −1.0887E−05 
                 −5.2921E−05  
               
               
                   
                 S8 
                 −8.3239E−04 
                 1.5106E−04 
                 −1.1710E−04 
                 2.7304E−05 
               
               
                   
                 S9 
                 −6.2349E−04 
                 1.4305E−04 
                 −7.5386E−05 
                 1.9243E−05 
               
               
                   
                 S10 
                  7.9872E−04 
                 4.3808E−04 
                  1.3148E−04 
                 4.2643E−05 
               
               
                   
                 S11 
                  1.4660E−03 
                 −3.0995E−05  
                 −1.5708E−04 
                 8.7665E−05 
               
               
                   
                 S12 
                  5.7376E−03 
                 −2.8717E−03  
                  9.2347E−04 
                 −1.5257E−04  
               
               
                   
                 S13 
                  3.7659E−03 
                 1.2150E−03 
                 −1.2527E−03 
                 2.3787E−04 
               
               
                   
                 S14 
                  7.8387E−03 
                 −3.5081E−03  
                  4.8957E−04 
                 −4.8793E−04  
               
               
                   
                   
               
            
           
         
       
     
       FIG. 14A  illustrates a longitudinal aberration curve of the optical imaging system according to example 7, representing deviations of focal points converged by light of different wavelengths after passing through the system.  FIG. 14B  illustrates an astigmatic curve of the optical imaging system according to example 7, representing a curvature of a tangential plane and a curvature of a sagittal plane.  FIG. 14C  illustrates a lateral color curve of the optical imaging system according to example 7, representing deviations of different image heights on an imaging plane after light passes through the system. It can be seen from  FIG. 14A  to  FIG. 14C  that the optical imaging system provided in example 7 may achieve good image quality. 
     EXAMPLE 8 
     An optical imaging system according to example 8 of the present disclosure is described below with reference to  FIG. 15  to  FIG. 16C .  FIG. 15  shows a schematic structural view of the optical imaging system according to example 8 of the present disclosure. 
     As shown in  FIG. 15 , the optical imaging system includes a first lens E 1 , a stop STO, a second lens E 2 , a third lens E 3 , a fourth lens E 4 , a fifth lens E 5 , a sixth lens E 6 , a seventh lens E 7  and an optical filter E 8 , which are sequentially arranged from an object side to an image side along an optical axis. 
     The first lens E 1  has negative refractive power, an object-side surface S 1  thereof is a concave surface, and an image-side surface S 2  thereof is a concave surface. The second lens E 2  has positive refractive power, an object-side surface S 3  thereof is a convex surface, and an image-side surface S 4  thereof is a convex surface. The third lens E 3  has negative refractive power, an object-side surface S 5  thereof is a concave surface, and an image-side surface S 6  thereof is a convex surface. The fourth lens E 4  has negative refractive power, an object-side surface S 7  thereof is a convex surface, and an image-side surface S 8  thereof is a concave surface. The fifth lens E 5  has positive refractive power, an object-side surface S 9  thereof is a convex surface, and an image-side surface S 10  thereof is a concave surface. The sixth lens E 6  has positive refractive power, an object-side surface S 11  thereof is a convex surface, and an image-side surface S 12  thereof is a convex surface. The seventh lens E 7  has negative refractive power, an object-side surface S 13  thereof is a convex surface, and an image-side surface S 14  thereof is a concave surface. The optical filter E 8  has an object-side surface S 15  and an image-side surface S 16 . The optical imaging system has an imaging plane S 17 , and light from an object sequentially passes through the respective surfaces S 1  to S 16  and is finally imaged on the imaging plane S 17 . 
     In example 8, a total effective focal length f of the optical imaging system is 1.98 mm, an aperture number Fno of the optical imaging system is 1.70, an on-axis distance TTL from the object-side surface S 1  of the first lens E 1  to the imaging plane S 17  is 6.42 mm, half of a diagonal length ImgH of an effective pixel area on the imaging plane S 17  is 2.75 mm, and half of a maximal field-of-view Semi-FOV is 65.9°. 
     Table 15 is a table illustrating basic parameters of the optical imaging system of example 8, wherein the units for the radius of curvature, the thickness/distance and the focal length are millimeter (mm). Table 16 shows high-order coefficients applicable to each aspheric surface in example 8, wherein the surface shape of each aspheric surface may be defined by the formula (1) given in the above example 1. 
     
       
         
           
               
               
               
             
               
                   
                 TABLE 15 
               
             
            
               
                   
                   
               
               
                   
                 Material 
                   
               
            
           
           
               
               
               
               
               
               
               
               
            
               
                 Surface 
                 Surface 
                 Radius of 
                 Thickness/ 
                 Refractive 
                 Abbe 
                 Focal 
                 Conic 
               
               
                 number 
                 type 
                 curvature 
                 Distance 
                 index 
                 number 
                 length 
                 coefficient 
               
               
                   
               
            
           
           
               
               
               
               
               
               
               
               
            
               
                 OBJ 
                 Spherical 
                 Infinite 
                 400.0000 
                   
                   
                   
                   
               
               
                 S1 
                 Aspheric 
                 −4.4832 
                 0.4631 
                 1.55 
                 56.1 
                 −3.98 
                 −48.8831 
               
               
                 S2 
                 Aspheric 
                 4.3612 
                 1.0129 
                   
                   
                   
                 −39.4747 
               
               
                 STO 
                 Spherical 
                 Infinite 
                 −0.0266 
               
               
                 S3 
                 Aspheric 
                 4.6075 
                 1.0634 
                 1.55 
                 56.1 
                 1.89 
                 26.1063 
               
               
                 S4 
                 Aspheric 
                 −1.2199 
                 0.0500 
                   
                   
                   
                 −1.5424 
               
               
                 S5 
                 Aspheric 
                 −10.4709 
                 0.2500 
                 1.68 
                 19.2 
                 −118.18 
                 88.9903 
               
               
                 S6 
                 Aspheric 
                 −12.1622 
                 0.0350 
                   
                   
                   
                 90.0000 
               
               
                 S7 
                 Aspheric 
                 9.8620 
                 0.2250 
                 1.67 
                 20.4 
                 −3.41 
                 48.4458 
               
               
                 S8 
                 Aspheric 
                 1.8320 
                 0.1168 
                   
                   
                   
                 −16.5809 
               
               
                 S9 
                 Aspheric 
                 5.8761 
                 0.8846 
                 1.55 
                 56.1 
                 7.76 
                 9.8780 
               
               
                 S10 
                 Aspheric 
                 −14.3993 
                 0.2227 
                   
                   
                   
                 89.3071 
               
               
                 S11 
                 Aspheric 
                 2.6854 
                 0.5565 
                 1.55 
                 56.1 
                 5.05 
                 −3.0633 
               
               
                 S12 
                 Aspheric 
                 99.0000 
                 0.3077 
                   
                   
                   
                 90.0000 
               
               
                 S13 
                 Aspheric 
                 1.0226 
                 0.4000 
                 1.64 
                 56.1 
                 −7.69 
                 −5.8720 
               
               
                 S14 
                 Aspheric 
                 0.7178 
                 0.4142 
                   
                   
                   
                 −3.1208 
               
               
                 S15 
                 Spherical 
                 Infinite 
                 0.1100 
                 1.62 
                 64.2 
               
               
                 S16 
                 Spherical 
                 Infinite 
                 0.3361 
               
               
                 S17 
                 Spherical 
                 Infinite 
               
               
                   
               
            
           
         
       
     
     
       
         
           
               
               
               
               
               
               
             
               
                 TABLE 16 
               
               
                   
               
             
            
               
                 Surface 
                   
                   
                   
                   
                   
               
               
                 number 
                 A4 
                 A6 
                 A8 
                 A10 
                 A12 
               
               
                   
               
               
                 S1 
                  4.9170E−01 
                 −9.4622E−02 
                 1.3675E−02 
                 −3.6720E−03 
                 1.6128E−03 
               
               
                 S2 
                  2.9135E−01 
                 −2.4624E−03 
                 2.8951E−03 
                 −8.3071E−05 
                 7.3135E−05 
               
               
                 S3 
                 −3.6524E−02 
                 −4.9515E−03 
                 −8.3859E−04  
                 −1.5765E−04 
                 −4.6550E−05  
               
               
                 S4 
                 −1.4447E−02 
                 −1.1249E−02 
                 2.2266E−03 
                 −9.9907E−04 
                 3.5901E−04 
               
               
                 S5 
                 −2.2905E−02 
                 −5.7246E−03 
                 8.5842E−03 
                 −1.2203E−03 
                 3.7272E−04 
               
               
                 S6 
                 −7.5618E−03 
                 −5.3002E−03 
                 9.5212E−03 
                 −7.0716E−05 
                 5.6805E−05 
               
               
                 S7 
                 −1.1857E−01 
                  9.7179E−03 
                 3.3313E−03 
                  2.3635E−04 
                 −3.2078E−04  
               
               
                 S8 
                  1.1699E−02 
                 −8.9390E−03 
                 1.9546E−03 
                 −1.4924E−03 
                 2.9177E−04 
               
               
                 S9 
                 −1.4979E−02 
                 −3.6692E−03 
                 1.2766E−03 
                  7.7352E−04 
                 −1.1699E−04  
               
               
                 S10 
                 −5.0351E−01 
                  6.2196E−02 
                 −1.9921E−03  
                  4.4512E−03 
                 1.5626E−03 
               
               
                 S11 
                 −4.9414E−01 
                 −4.9746E−02 
                 4.2279E−03 
                  9.9522E−04 
                 2.8729E−03 
               
               
                 S12 
                 −4.9909E−02 
                 −3.0220E−02 
                 1.5141E−02 
                  1.2042E−03 
                 −2.4675E−04  
               
               
                 S13 
                 −1.4346E+00 
                  3.0819E−01 
                 3.6116E−03 
                 −2.3629E−03 
                 −7.5139E−03  
               
               
                 S14 
                 −1.3252E+00 
                  2.3658E−01 
                 −8.7312E−02  
                  3.2027E−02 
                 −7.9054E−03  
               
               
                   
               
            
           
           
               
               
               
               
               
               
            
               
                   
                 Surface 
                   
                   
                   
                   
               
               
                   
                 number 
                 A14 
                 A16 
                 A18 
                 A20 
               
               
                   
                   
               
               
                   
                 S1 
                 −3.6274E−04 
                 8.0280E−05 
                 −3.3956E−05 
                 6.1591E−06 
               
               
                   
                 S2 
                  8.4243E−05 
                 6.4205E−06 
                  2.2746E−05 
                 2.5386E−06 
               
               
                   
                 S3 
                 −1.3026E−05 
                 −9.6888E−06  
                 −2.1428E−06 
                 −3.1395E−06  
               
               
                   
                 S4 
                 −1.4005E−04 
                 4.3313E−05 
                 −9.1319E−06 
                 7.5207E−07 
               
               
                   
                 S5 
                 −3.5561E−04 
                 1.2257E−04 
                 −8.7592E−06 
                 4.3086E−06 
               
               
                   
                 S6 
                 −2.8524E−04 
                 2.7169E−05 
                  1.5409E−05 
                 −1.9026E−06  
               
               
                   
                 S7 
                 −1.7053E−04 
                 4.8843E−05 
                  1.8046E−05 
                 −7.0029E−06  
               
               
                   
                 S8 
                 −2.1042E−04 
                 7.8208E−05 
                 −3.4760E−05 
                 6.2030E−06 
               
               
                   
                 S9 
                 −1.3047E−05 
                 −1.0638E−05  
                 −1.1573E−06 
                 1.4840E−06 
               
               
                   
                 S10 
                  9.1070E−04 
                 7.3151E−05 
                  1.1786E−04 
                 −1.3480E−05  
               
               
                   
                 S11 
                  3.0528E−03 
                 −3.7499E−04  
                 −2.5275E−04 
                 −3.5319E−05  
               
               
                   
                 S12 
                  1.6489E−03 
                 −3.3610E−03  
                  6.0160E−04 
                 3.1834E−04 
               
               
                   
                 S13 
                 −1.6751E−03 
                 7.0025E−04 
                 −2.7073E−04 
                 3.6373E−04 
               
               
                   
                 S14 
                  3.9914E−03 
                 −1.0494E−03  
                  2.9261E−04 
                 −1.0087E−04  
               
               
                   
                   
               
            
           
         
       
     
       FIG. 16A  illustrates a longitudinal aberration curve of the optical imaging system according to example 8, representing deviations of focal points converged by light of different wavelengths after passing through the system.  FIG. 16B  illustrates an astigmatic curve of the optical imaging system according to example 8, representing a curvature of a tangential plane and a curvature of a sagittal plane.  FIG. 16C  illustrates a lateral color curve of the optical imaging system according to example 8, representing deviations of different image heights on an imaging plane after light passes through the system. It can be seen from  FIG. 16A  to  FIG. 16C  that the optical imaging system provided in example 8 may achieve good image quality. 
     In view of the above, examples 1 to 8 respectively satisfy the relationship shown in Table 17. 
     
       
         
           
               
               
               
               
               
               
               
               
               
             
               
                 TABLE 17 
               
               
                   
               
               
                 Conditional/Example 
                 1 
                 2 
                 3 
                 4 
                 5 
                 6 
                 7 
                 8 
               
               
                   
               
             
            
               
                   
               
            
           
           
               
               
               
               
               
               
               
               
               
            
               
                 f1/f2 
                 −2.11 
                 −2.12 
                 −2.10 
                 −2.09 
                 −2.07 
                 −2.11 
                 −2.09 
                 −2.11 
               
               
                 f4/f 
                 −1.74 
                 −1.70 
                 −1.75 
                 −1.75 
                 −1.72 
                 −1.73 
                 −1.75 
                 −1.73 
               
               
                 f7/f6 
                 −1.31 
                 −1.71 
                 −1.56 
                 −2.09 
                 −1.30 
                 −1.52 
                 −2.09 
                 −1.52 
               
               
                 R1/R4 
                 3.67 
                 3.65 
                 3.60 
                 3.59 
                 3.57 
                 3.68 
                 3.59 
                 3.68 
               
               
                 R3/R2 
                 1.05 
                 1.05 
                 1.04 
                 1.04 
                 1.05 
                 1.06 
                 1.04 
                 1.06 
               
               
                 R9/(R8 + R11) 
                 1.34 
                 1.21 
                 1.37 
                 1.70 
                 1.31 
                 1.30 
                 1.70 
                 1.30 
               
               
                 (R13 + R14)/(R13 − R14) 
                 4.74 
                 5.44 
                 4.72 
                 4.68 
                 4.71 
                 5.71 
                 4.68 
                 5.71 
               
               
                 CT5/(CT3 + CT4) 
                 1.84 
                 1.82 
                 1.84 
                 1.84 
                 1.82 
                 1.86 
                 1.84 
                 1.86 
               
               
                 ΣCT/CT2 
                 3.63 
                 3.68 
                 3.62 
                 3.54 
                 3.73 
                 3.61 
                 3.54 
                 3.61 
               
               
                 ΣAT/T12 
                 1.74 
                 1.73 
                 1.78 
                 1.83 
                 1.69 
                 1.74 
                 1.83 
                 1.74 
               
               
                 CT6/T67 
                 1.83 
                 1.94 
                 1.67 
                 1.45 
                 2.18 
                 1.81 
                 1.45 
                 1.81 
               
               
                   
               
            
           
         
       
     
     The present disclosure further provides an imaging apparatus, which is provided with an electronic photosensitive element for imaging. The electronic photosensitive element may be a photosensitive Charge-Coupled Device (CCD) or a Complementary Metal-Oxide Semiconductor (CMOS). The imaging apparatus may be an independent imaging device such as a digital camera, or may be an imaging module integrated in a mobile electronic device such as a mobile phone. The imaging apparatus is equipped with the optical imaging system described above. 
     The foregoing is only a description of the preferred examples of the present disclosure and the applied technical principles. It should be appreciated by those skilled in the art that the protective scope of the present disclosure is not limited to the technical solutions formed by the particular combinations of the above technical features. The protective scope should also cover other technical solutions formed by any combinations of the above technical features or equivalent features thereof without departing from the concept of the invention, such as, technical solutions formed by replacing the features as disclosed in the present disclosure with (but not limited to), technical features with similar functions.